HERMETICALLY CLOSED CAPACITOR FOR IMPLANTABLE MEDICAL DEVICE

专利摘要:
The present invention relates to a wet electrolytic capacitor (10) comprising an anode, anode wire (220), an electrolyte, a housing (12) having a wall that defines an anode wire port (34), and an sealing assembly (300). The seal assembly (300) is connected to the housing (12) at the anode wire port (34), and a portion of the anode wire (220) extends therethrough . The seal assembly (300) includes an insulating tube (306), a metal plate (301), and an elastomeric ring (311). The tube receives the anode wire (220) and has a first portion extending through the anode wire port (34) and a second portion located within an interior of the housing (12). The plate is adjacent to an outer surface (27) of the wall, covers the anode wire port (34), and contains an orifice. The ring is positioned adjacent an inner surface of the wall and contains an orifice.
公开号:FR3028659A1
申请号:FR1560794
申请日:2015-11-12
公开日:2016-05-20
发明作者:Lotfi Djebara；Radek Matousek；Ludek Kubes
申请人:AVX Corp；
IPC主号:

专利说明:

[0001] 1 HERMETICALLY CLOSED CAPACITOR FOR IMPLANTABLE MEDICAL DEVICE High voltage electrolytic capacitors are used as energy storage tanks in a large number of applications, including implantable medical devices. Since it is desirable to minimize the overall size of the implanted device, these capacitors are necessary to have a high energy density. This is particularly true of an implantable cardioverter defibrillator ("ICD"), which is also referred to as an implantable defibrillator, since the high voltage capacitors used to deliver the defibrillation pulse can occupy up to one third of the implantable defibrillator. volume of the DCI. While advances have been made in minimizing the overall size of the capacitors used in ICDs through the use of tantalum planar anodes which have a large internal surface area but a very small thickness for easy incorporation. in ICDs, problems still exist. For example, the flat anodes are anodized and then sealed in a housing containing a highly conductive and generally corrosive liquid electrolyte solution, where an anode wire extends from the housing.
[0002] Unfortunately, these wet capacitors may experience problems when the electrolyte leaks from the housing at the seal around the anode wire. For example, gases (such as hydrogen) can be released during operation, causing pressure build-up within the capacitor. In view of the foregoing, a gastight hermetic seal (eg, a metal-glass-to-metal hermetic seal) is often used, allowing the anode wire to extend safely. However, the metal-glass-metal hermetic seal itself can sometimes become corroded by the liquid electrolyte and leak, and the small thickness of the housing makes it extremely difficult to design a metal-glass-to-metal hermetic seal that can prevent effectively leak the electrolyte. Thus, there is currently a need for a hermetically sealed wet electrolytic capacitor for use in implantable medical devices, such as defibrillators. According to one embodiment of the present invention, a wet electrolytic capacitor for an implantable medical device is disclosed which contains a planar anode, a working electrolyte, a housing, and a sealing assembly. The planar anode comprises a porous anode body coated with a dielectric layer, wherein an anode wire extends from the porous anode body, and the working electrolyte is in electrical contact with the porous anode body. flat anode. The planar anode and working electrolyte are positioned within an interior of the housing, and the housing has a wall that defines an anode wire port.
[0003] The seal assembly is connected to the housing at the anode wire port and includes a metal housing, an elastomeric ring, and a metal plate. The metal housing, which is positioned within the anode wire port and extends into the interior of the housing, defines a cavity in which a portion of the anode wire extends. The elastomeric ring, which is positioned within the cavity, contains an orifice through which a portion of the anode wire extends. The metal plate is also positioned within the cavity, and also contains an orifice through which a portion of the anode wire extends. In addition, a lower surface of the metal plate is in contact with the elastomeric ring within the cavity. According to another embodiment of the present invention, a method of forming an electrolytic capacitor for an implantable medical device is disclosed. The method comprises positioning a planar, porous anode body having anode wire extending therefrom within a housing having a sidewall into which a wire port is located. Anode is formed such that a portion of the anode wire extends through the anode wire port, wherein a seal assembly surrounds the anode wire at the orifice. anode wire. The seal assembly includes a metal housing positioned within the anode wire port and extending into an interior of the housing, wherein the metal housing defines a cavity through which a portion of the wire anode extends; an elastomeric ring positioned within the cavity, wherein the elastomeric ring contains an orifice through which a portion of the anode wire extends; and a metal plate positioned within the cavity, wherein the metal plate contains an orifice through which a portion of the anode wire extends, and wherein a lower surface of the metal plate is in contact with the elastomeric ring inside the cavity. The method further comprises forming a hermetic seal between the seal assembly and the anode wire. Other features and aspects of the present invention are discussed in more detail below. A complete description of the present invention which allows its reproduction, including its best mode, intended for those skilled in the art, is proposed more particularly in the remainder of the specification, which refers to the appended figures in which: FIG. 1 is a perspective view of an embodiment of the wet electrolytic capacitor of the present invention; Fig. 2 is a top view of an embodiment of an anode which may be used in the capacitor of the present invention; Figure 3 is a front view of the anode of Figure 2; Fig. 4 is a perspective view illustrating the entire anode of Fig. 2 in a housing for forming the capacitor shown in Fig. 1; Fig. 5 is an exploded perspective view of the sealing assembly used to hermetically seal the anode wire to the housing at an anode wire port in the housing; Figure 6 is an exploded cross-sectional view of the seal assembly of Figure 5; Figure 7 is an assembled perspective view of the sealing assembly of Figures 5 and 6; Figure 8 is a cross-sectional view of a portion of the housing after sealing the anode wire with the sealing assembly of Figures 5 to 7; Fig. 9 is an assembled perspective view of the sealing assembly of Figs. 5 to 7 showing where the assembly is welded during assembly of the capacitor; Figure 10 is an assembled cross-sectional view of the seal assembly of Figures 5-7 showing where the metal plate is welded to the elastomeric ring; and Fig. 11 is an assembled cross-sectional perspective view of the sealing assembly of Figs. 5 to 7 showing where the metal housing is welded to the housing. The repeated use of reference characters in the present specification and drawings is intended to represent like or similar features or elements of the invention. It will be understood by those skilled in the art that the present discussion is a description of exemplary embodiments only, which is not intended to limit the broader aspects of the present invention, said broader aspects being implemented. in the build example. In general, the present invention relates to a wet electrolytic capacitor for an implantable medical device which contains a planar anode comprising a porous anode body coated with a dielectric layer, an anode wire extending from the body a porous anode, a working electrolyte which is in electrical contact with the planar anode, a housing within which the planar anode and the working electrolyte are positioned and which has a wall which defines an orifice anode wire, and a sealing assembly which is connected to the housing at the anode wire port and through which a portion of the anode extends. In particular, the sealing assembly comprises the metal housing, a metal plate, and an elastomeric ring. The metal housing is positioned within the anode wire port and extends into an interior of the housing and defines a cavity through which a portion of the anode wire extends. However, the elastomeric ring rests within the cavity, like the metal plate, where a lower surface of the metal plates is in contact with the elastomeric ring within the cavity. In some embodiments, the elastomeric ring may have a tapered portion that can be positioned within the cavity, where the cavity has a corresponding taper to receive the elastomeric ring. The seal assembly may optionally include an insulating tube which receives the anode wire and has a first portion extending through the anode wire port and a second portion extending through the anode wire port inside the housing. Such an arrangement of the seal assembly creates a hermetic seal at the anode wire port. The present invention also relates to a method of forming a wet electrolytic capacitor for use in an implantable medical device. The method comprises positioning a planar, porous anode body having anode wire extending therefrom within a housing having a sidewall into which a wire port is located. Anode is formed such that a portion of the anode wire extends through the anode wire port, wherein a seal assembly surrounds the anode wire at the orifice. anode wire. The seal assembly includes a metal housing positioned within the anode wire port and extending into an interior of the housing, wherein the metal housing defines a cavity through which a portion of the wire anode extends; an elastomeric ring positioned within the cavity, wherein the elastomeric ring contains an orifice through which a portion of the anode wire extends; and a metal plate positioned within the cavity, wherein the metal plate contains an orifice through which a portion of the anode wire extends, and wherein a lower surface of the metal plate is in contact with the elastomeric ring inside the cavity. The method further comprises forming a hermetic seal between the seal assembly and the anode wire. The present inventors have found that the particular arrangement of the sealing assembly discussed above and comprising a metal housing, a metal plate, an elastomeric ring, and an optional insulating tube, as well as the sealing method of an anode wire port formed in a capacitor housing using the components of the sealing assembly 10 discussed above, results in a wet electrolytic capacitor having an improved hermetic seal around the anode wire such that that the working electrolyte does not leak from the anode wire port from which the anode wire extends. For example, the components in the resulting elastomer metal seal can prevent fluid leakage at the anode wire port because the components can be made with very large tolerances because of the materials used. Further, as a result of the small size of the seal assembly, the thickness of the condenser housing in which the seal assembly is used can be minimized, the thickness being critical for wet electrolytic capacitors in ICDs 25 because a too thick housing makes it difficult to implant ICDs in the body. On the other hand, glass-on-metal joints generally do not prevent these leaks when used in wet electrolytic capacitors. In addition, without wishing to be bound by theory, it is believed that the inclusion of a metal housing in combination with a metal plate can further enhance the effectiveness of the hermetic seal by protecting the elastomeric ring during assembly. and reducing the amount of contact between the elastomeric ring and the working electrolyte. Various embodiments of the present invention will now be described in more detail. I. Sealing assembly 10 Referring to Figs. 1 and 5 to 11, an embodiment of a seal assembly 300 will now be described in more detail. The seal assembly 300 is connected to the housing 12 of the capacitor 10 and provides a hermetic seal through which the anode wire 220 can extend safely. Specifically, the seal assembly 300 can hermetically seal an anode wire port 34 formed in a side wall 200 of a housing member 14 of the wet electrolytic capacitor 20 and through which the anode lead 220 of the capacitor electrolytic wet extends (see Figure 1). In an embodiment as shown in FIGS. 5 to 11, the sealing assembly 300 comprises a metal plate 301, an elastomeric ring 311, and a metal housing 317, where the metal plate 301 and the elastomeric ring 311 include apertures 325 and 327, respectively, which define a channel through which the anode wire 220 and an optional insulating tube 306 can extend. However, the metal housing 317 includes a cavity 328 in which the elastomeric ring 311 and the metal plate 301 are positioned. Generally, the metal plate 301 is in contact with an upper surface 312 of the elastomeric ring 311 and can serve as a cover for holding the elastomeric ring 311 within the cavity 328. As shown in FIGS. 8, the metal plate 301 has an upper surface 302 and a lower surface 303. The metal plate 301 may also have an inner diameter 304 and an outer diameter 305, the inner diameter 304 defining a metal plate orifice 325 through which the anode wire 220 may extend, the metal plate 301 being positioned in a cavity 328 of the metal housing 317 at the anode wire port 34 formed in the capacitor housing 12. The plate orifice metal 325 as defined by the inner diameter 304 may have a diameter of from about 0.001 millimeter to about 3 millimeters, for example from about 0.005 millimeter to about about 2.5 millimeters, for example from about 0.01 millimeter to about 2 millimeters insofar as the optional insulation tube 306 and the anode wire 220 surrounded by the insulating tube 306 (if applicable) can extend 25 In addition, the inner diameter 304 of the metal plate 301 may be generally constant along the entire length of the metal plate 301 in the y direction to maintain a close contact with the wire of the metal plate 301. anode 220 or 30 the insulating tube 306 surrounding the anode wire 220, if appropriate. However, the outer diameter 305 may be any diameter in that the metal plate 301 can fit tightly within the metal housing 317. For example, the outer diameter may be less than about 8 millimeters, for example from about 0.025 millimeter to about 6.5 millimeters, for example from about 0.05 millimeter to about 5 millimeters, for example from about 0.075 millimeter to about 4 millimeters. Further, although the metal plate 301 is presented as a ring or disk of circular shape, this is not necessary, and the outer dimensions of the metal plate can form any suitable shape, for example oval, square, rectangular, triangular, etc., in that the shape corresponds to the shape of the metal housing 317 in which the metal plate 301 is disposed and with which the metal plate 301 creates a tight fit. In addition, the elastomeric ring 311 of the seal assembly 300 has an upper surface 312 and a lower surface 313. The elastomeric ring 311 has an inner diameter 314, a first outer diameter 315 at its upper surface 312, and a second outer diameter 316 at its lower surface 313, where in some embodiments the second outer diameter 316 may be smaller than the first outer diameter 315.The inner diameter 314 defines an elastomeric ring orifice 327 across which the optional insulation tube 306 and the anode wire 220 which the insulation tube 306 surrounds (if appropriate) can extend. For example, the elastomeric ring orifice 327 as defined by the inner diameter 314 may have a diameter of from about 0.001 millimeter to about 3 millimeters, for example from about 0.005 millimeter to about 2.5 millimeters, for example 0.01 millimeter to about 2 millimeters, since the anode wire 220 and the optional insulation tube 306 can extend through the elastomeric ring hole 327 so that the elastomeric ring 311 maintains a close contact with the insulating tube 306 to ensure a tight seal. Further, the inner diameter 314 of the elastomeric ring 311 is generally constant over the entire length of the elastomeric ring 311 in the y direction to maintain close contact with the insulating tube 306 surrounding the anode wire 220. However, in In some embodiments, the upper surface 312 of the elastomeric ring 311 may have a larger first outer diameter 315 which narrows along the length of the elastomeric ring 311 in the y direction so that the bottom surface 313 has a second diameter. outer 316 lower. Such taper can provide sufficient contact with the metal housing 317 that can support the elastomeric ring 311 and creates a seal with the housing 12 as discussed in more detail below. Then, the metal housing 317 may have an upper surface 318 and a lower surface 319. The metal housing 317 has a first inner diameter 320, a second inner diameter 322, a first outer diameter 321, and a second outer diameter 323. first inner diameter 320 and the second inner diameter 322 define a metal housing cavity 328 through which the anode wire 220 and the insulating tube 306, if present, can extend. The first inner diameter 320 of the metal housing 317 may be larger than the second inner diameter 322 so that it can receive and support the metal plate 301 and the elastomeric ring 311 while creating a tight or narrow fit between the components. Further, the metal housing 317 can shrink from the upper surface 318 to the bottom surface 319 in a manner similar to the elastomeric ring 311 so that contact between the elastomeric ring 311 and the metal housing 317 can increase. to provide a seal when the metal plate 301 is placed above the elastomeric ring 311 to serve as a cover to hold the elastomeric ring 311 firmly in place in the metal housing 317. In other words, the upper surface 318 The metal housing 317 has a larger inner diameter 320 larger and a larger first outer diameter 321 which decrease along the length of the metal housing 317 in the y direction so that the lower surface 319 has a smaller second diameter. 322 interior and a second smaller outer diameter 323. For example, the second inner diameter 322 through which the tub optional insulation 306 and anode wire 220 may be inserted from about 0.001 millimeter to about 3 millimeters, for example from about 0.005 millimeter to about 2.5 millimeters, for example about 3028659, 1 millimeter to about 2 millimeters, insofar as the insulating tube 306 and the surrounding anode wire 220 can extend through the metal housing cavity 328 so that the metal housing 317 maintains contact narrow with the anode wire 220 or the insulating tube 306 to provide a seal. However, the first inner diameter 320 is large enough to accommodate the metal plate 301 and the elastomeric ring 311, while being small enough to provide a seal between the components, for example by laser welding or spot welding. For example, the first inner diameter 320 may generally have a diameter that is the same as the outer diameter 305 of the metal plate 301 and the first outer diameter 315 of the elastomeric ring 311. Thus, the metal housing 317 may have a cavity 333 to receive the elastomeric ring 311 and the metal plate 301, as specifically illustrated in FIGS. 6 and 8. In addition, the optional insulation tube 306, which can isolate the anode wire 220 from the other components of FIG. the sealing assembly 300, like the metal plate 301, as well as the housing 12 of the capacitor 25, has an inside diameter 309, in which the inside diameter 309 defines an insulating tube 326 through which the anode wire 220 can expand. The insulating tube 306 also has an upper end 329 and a lower end 330.
[0004] The insulating tube port 326 as defined by the inner diameter 309 may have a diameter of from about 0.001 millimeter to about 3 millimeters, for example from about 0.005 millimeter to about 2.5 millimeters, for example about 0.01 millimeter to about 2 millimeters, since the anode wire 220 can extend through the insulating tube port 326 and maintain close contact with the insulating tube 306 to provide a seal. In addition, the inner diameter 309 of the insulating tube 306 is generally constant along the entire length of the insulating tube 306 in the y direction to maintain close contact with the anode wire 220 over the entire length of the insulating tube 306. The different The components of the sealing assembly 300 discussed above may be configured to receive the anode wire 220 of the capacitor 10 so as to create a hermetic seal between the anode wire 220 and the housing 12 at the level of the Anode wire port 34. For example, referring to FIGS. 6 and 8, the elastomeric ring 311 can be inserted into the metal housing 317 so that the bottom surface 313 of the elastomeric ring 311 is in contact with the metal housing 317 to its lower surface 319. Then, the metal plate 301 can be inserted into the metal housing 317 such that a lower surface 303 of the metal plate 301 is in contact with an upper surface 312 of the elastomeric ring 311. After this, the seal assembly 300 can be inserted or press fit into the anode wire port 34 in a side wall 14 of the housing (see Fig. 1) from outside the housing 12 or 3028659 16 from inside the housing 13. Next, the anode wire 220 may be inserted through the cavity 328 of the metal housing 317, the elastomeric ring orifice. 327, and the metal plate orifice 325.
[0005] In addition, if an insulating tube 306 is used, the anode wire 220 may be first inserted into the insulating tube hole 326 of the insulating tube 306, where the insulating tube orifice as defined by the diameter Insulating tube interior 309 is just wide enough to fit around the diameter 221 of the anode wire 220 and create a tight fit, after which the anode wire 220 and the insulating tube 306 can be inserted into the cavity 328. metal housing 317, elastomeric ring hole 327, and metal plate hole 325, wherein the insulating tube 306 may have a first portion extending out of the outside of the side wall 20 of the first housing member 12 and a second portion extending into the interior 13 of the housing 12 at the elastomeric ring 311. Alternatively, the insulating tube 306 may be inserted into the orifices of the sealing assembly 300 before insertion of the anode wire 220, after which anode wire 220 may be inserted through cavity 328 of metal housing 317, elastomeric ring port 327, and metal plate port 325 as discussed above. Either way, the anode wire 220 and the optional insulation tube 306 may extend from the outer surface 27 of the side wall such that a first portion of the anode wire 220 and a first part of the insulating tube 306 extend beyond the outer surface 27 of the side wall 20, while a second portion of the anode wire 220 and a second portion of the insulating tube 306 remain within the housing, where the insulating tube 306 can generally act as a sleeve which fits closely around the anode wire 220. Regardless of the particular manner of inserting the seal assembly 300 into the wire port of anode 34, once the sealing assembly 300 is in place and after insertion and proper positioning of the anode wire 220 into the seal assembly 300, the metal plate 301 and the elastomeric ring 311 can be welded together, just like the 301 metal housing and the first housing member 14 to ensure that the anode wire 220 is hermetically sealed at the anode wire port. Referring to FIGS. 9 to 11, the locations of the different soldering points are illustrated. For example, as shown in FIG. 9, the metal plate 301 may be welded, for example by laser welding or spot welding, around its circumference, where the solder at the weld zone 335 effective seal between the metal plate 301 and the elastomeric ring 311 (not shown). Fig. 10 is a cross-sectional perspective view showing a weld zone 335, where the metal plate 301 can be welded to the elastomeric ring 311 to create an effective seal of the anode wire 220 at the port of Anode wire 34. However, the metal housing 317 may be welded, for example by laser welding or spot welding, around its circumference at the weld zone 336 to provide an effective seal between the metal housing 317. and the side wall 20 of the first housing member 14. Fig. 11 is a cross-sectional perspective view showing a weld zone 336, where the metal housing 317 may be welded to the side wall of the first housing member 14 at the an upper surface 27 of the side wall 20. The overall effect of sealing the metal plate 301 to the elastomeric ring 311 and the metal housing 317 to the sidewall 20 is t the creation of a hermetic seal that is generally glass-free and can create a more effective seal compared to glass-on-metal joints.
[0006] The components of the above-mentioned seal assembly 300 may be formed from any material to the extent that an effective hermetic seal can be formed. For example, the metal plate 301 and the optional metal housing 317 may be formed of a conductive material, such as a metal. For example, the metal plate 301 and the optional metal housing 317 may be of tantalum, niobium, aluminum, nickel, hafnium, titanium, copper, silver, steel (eg, stainless), alloys thereof (e.g. electroconductive oxides), composites thereof (e.g., an electroconductive oxide-coated metal), and so on. In a particular embodiment, the metal plate 301 and the metal housing 317 may comprise titanium.
[0007] However, the insulating tube 306 may be of any suitable insulating material. For example, the insulating material may have an electrical resistance of about 1 x 102 ohm-m or greater, in some embodiments of about 1 x 105 ohm-m or more, and in some embodiments, about 1 x 1015 to about 1 x 1025 ohm-m, determined at a temperature of 20 ° C. For example, glass materials may be used as insulating material, such as glass compositions containing CaO, Al 2 O 3, B 2 O 3, SrO, BaO, LiO 2, SiO 2, TiO 2, SiO 2 Na2O, combinations thereof, etc. Barium lanthanoborate glass compositions which contain boron oxide (B2O3), barium oxide (BaO), lanthanum oxide (LiO2) and optionally at least one other oxide , are particularly suitable. These compositions can be described in more detail in U.S. Patent Nos. 5,648,302 and 5,104,738 issued to Brow, et al.
[0008] Still other insulating materials may include polymeric materials, such as fluorinated polymers (for example, polytetrafluoroethylene ("PTFE"), a perfluoroalkyl vinyl ether ("PVE"), a poly (tetrafluoroethylene-co-ether perfluoroalkyl vinyl) ("PFA"), a fluorinated ethylene-propylene copolymer ("FEP"), an ethylene-tetrafluoroethylene copolymer ("ETFE"), polyvinylidene fluoride ("PVDF"), polychlorotrifluoroethylene ("PCTFE"), and copolymers of TFE with VF2 and / or HFP, etc.); polyvinyl chloride ("PVC"), polysulfones (for example, polysulfone, polyethersulfone, etc.); polyimides (for example, polyetherimide); polyolefins (for example, polyethylene, polypropylene, etc.); and so on, as well as the mixtures thereof. In addition, the elastomeric ring 311 may be formed of any suitable elastomer. For example, the elastomeric ring 311 may be formed of any elastomer that is resistant to electrolyte corrosion (discussed below) and has sufficient dielectric strength to withstand the maximum voltage generated by the capacitor. In one embodiment, the elastomer can perform well over a temperature range of about -55 ° C to about 200 ° C without degradation or loss of elasticity. Examples of elastomers that may be used include butyl rubber, chlorobutyl rubber, ethylene propylene rubber (EPR), ethylene propylene diene rubber (EPDM), fluorinated elastomers, such as Vitam ™, polytetrafluoroethylene, polychloropropene rubber , a butadiene rubber, a nitrile rubber, an isoprene rubber, a silicone rubber, and a styrene-butadiene rubber.
[0009] The seal assembly of the present invention, as described above, can generally be incorporated into a wet electrolytic capacitor using any of a variety of techniques known in the art. In this regard, the various additional components of the wet electrolytic capacitor will be discussed in more detail with reference to Figs. 1 to 4. II. Flat Anode The planar anode is typically formed from a valve metal composition. The specific charge of the composition may vary, for example from about 2000 pF * V / g to about 80,000 pF * V / g, in some embodiments from about 5000 pF * V / g to about 40 000 pF * V / g or more, and in some embodiments, from about 10,000 to about 20,000 pF * V / g. The valve metal composition contains a valve metal (in other words, a metal that is capable of oxidation) or a valve metal compound, such as tantalum, niobium, aluminum, hafnium, titanium, alloys thereof, oxides thereof, nitrides thereof, and so on. For example, the valve metal composition may contain an electroconductive niobium oxide, such as niobium oxide having an atomic ratio of niobium to oxygen of 1 / 1.0 ± 1.0, in some embodiments of the invention. 1 / 1.0 ± 0.3, in some embodiments 1 / 1.0 ± 0.1, and in some embodiments, 1 / 1.0 ± 0.05. The niobium oxide can be NbO0.7, NbO0.0, Nb01.1, and NbO2. Examples of such valve metal oxides are disclosed in U.S. Patent Nos. 6,322,912 issued to Fife; 6,391,275 issued to Five et al., 6,416,730 issued to Five et al., 6,527,937 issued to Fife; 6,576,099 issued to Kimmel, et al. ; 6,592,740 issued to Fife, et al. ; and 6,639,787 issued to Kimmel, et al. ; and 7,220,397 issued to Kimmel, and 3028659 22 al., as well as in Patent Application Publication Nos. 2005/0019581 issued to Schnitter; 2005/0103638 issued to Schnitter, et al. ; 2005/0013765 issued to Thomas, et al.
[0010] To form the planar anode, a powder of the valve metal composition is generally used. The powder may contain particles of any of a variety of forms, for example, nodular, angular, lamellar, etc., as well as mixtures thereof. Particularly suitable powders are tantalum powders available from Cabot Corp. (For example, C255 lamellar powder, TU4D lamellar / modular powder, etc.) and H.C. Starck (eg, NH175 nodular powder). The valve metal composition can be formed using techniques known to those skilled in the art. A precursor tantalum powder, for example, may be formed by reducing a tantalum salt (for example, potassium fluotantalate (K2TaF7), sodium fluotantalate (Na2TaF7), tantalum pentachloride (TaC15), etc. .) with a reducing agent (eg, hydrogen, sodium, potassium, magnesium, calcium, etc.). Regardless of the particular method used, the resulting powder may have certain characteristics that enhance its ability to be formed into a capacitor anode. For example, the particles used in the anode may be generally flat. The degree of flatness is generally defined by the "aspect ratio" in other words, the average diameter or the width of the particles divided by the average thickness ("D / T"). For example, the aspect ratio of the particles may be from about 2 to about 100, in some embodiments from about 3 to about 50, in some embodiments, from about 4 to about 30. may also have a specific surface area of from about 0.5 to about 10.0 m 2 / g, in some embodiments from about 0.7 to about 5.0 m 2 / g, and in some embodiments, From about 1.0 to about 4.0 m 2 / g. The term "specific surface area" is defined in more detail above. Apparent density (also known as Scott's density) is also typically from about 0.1 to about 2 grams per cubic centimeter (g / cc), in some embodiments from about 0.2 g / cc to about 1.5 g / cc, and in some embodiments from about 0.4 g / cc to about 1 g / cc. "Bulk density" can be determined using a funnel flow meter and a density cut. More specifically, the sample may be poured through the funnel into the cup until the sample completely fills the cup and covers the periphery, after which the sample will be leveled with a spatula, without shaking, of so that it is at the same level as the top of the cup. The leveled sample is transferred to a scale and weighed to the nearest 0.1 gram to determine the density value. Such an apparatus is available from Alcan Aluminum Corp. Elizabeth, New Jersey. The particles may also have an average size (e.g., width) of from about 0.1 to about 100 micrometers, in some embodiments from about 0.5 to about 70 micrometers, and in some embodiments. from about 1 to about 50 microns. To facilitate the construction of the planar anode, some additional components may also be included in the powder. For example, the powder may optionally be mixed with a binder and / or a lubricant to ensure that the particles adhere to each other as they are compressed to form the planar anode body. Suitable binders may include, for example, polyvinyl butyral, polyvinyl acetate; polyvinyl alcohol; poly (vinyl pyrrolidone); cellulosic polymers, such as carboxymethylcellulose, methylcellulose, ethylcellulose, hydroxyethylcellulose, and methylhydroxyethylcellulose; atactic polypropylene, polyethylene; polyethylene glycol (for example, Carbowax from Dow Chemical Co.); polystyrene, polybutadiene / styrene; polyamides, polyimides, and polyacrylamides, polyl ethers of high molecular weight; copolymers of ethylene oxide and propylene oxide; fluorinated polymers, such as polytetrafluoroethylene, polyvinylidene fluoride, and fluoroolefin copolymers; acrylic polymers, such as sodium polyacrylate, poly (lower alkyl acrylates), poly (lower alkyl methacrylates) and copolymers of lower alkyl acrylates and methacrylates; and fatty acids and waxes, such as stearic and other saponified fatty acids, vegetable wax, microwaxes (purified paraffins), and the like. The binder can be dissolved and dispersed in a solvent. Examples of the solvent may include water, alcohols, and so on. When used, the percentage of binders and / or lubricants can vary from about 0.1% to about 8% by weight of the total mass. It should be understood, however, that binders and / or lubricants are not necessarily required in the present invention. The resulting powder can be compacted to pellet using any conventional powder press device. For example, a press die may be used which is a single station compaction press containing a die and one or more punches. Alternatively, anvil-type compaction press dies can be used that use only a die and a single lower punch. The single station compaction press dies are available in several basic types, for example, cam, toggle and eccentric / crank presses having variable capacities, eg single acting, double acting, floating die, with moving plate, opposed piston, screw, impact, heat compression, stamping or calibration. The powder can be compacted around anode wire, such as anode wire. The anode wire may be formed from any electroconductive material, such as tantalum, niobium, aluminum, hafnium, titanium, etc., as well as electroconductive oxides and / or their nitrides. In addition, the anode wire may have a diameter of about 0.001 millimeter to about 3 millimeters, for example from about 0.005 millimeter to about 2.5 millimeters, for example from about 0.01 millimeter to about 5 millimeters. 2 millimeters. Any binder / lubricant can be removed after compression by heating the pellet under vacuum at a certain temperature (e.g., from about 150 ° C to about 500 ° C) for several minutes. Alternatively, the binder / lubricant may also be removed by contacting the pellet with an aqueous solution, as described in US Patent No. 6,197,252 issued to Bishop, et al. After this, the pellet is sintered to form a porous integral mass. The present inventors have found that certain sintering conditions could result in an increase in the specific charge of the resulting planar anode, as well as an increase in the breakdown voltage of the resulting capacitor. More particularly, the pellet 20 is typically sintered at a temperature of about 800 ° C to about 2000 ° C, in some embodiments from about 1200 ° C to about 1800 ° C, and in some embodiments. from about 1500 ° C to about 1700 ° C for a period of about 25 minutes to about 100 minutes, and in some embodiments from about 8 minutes to about 15 minutes. This can happen in one or more steps. If desired, sintering can occur in an atmosphere that limits the transfer of oxygen atoms to the planar anode. For example, sintering may occur in a reducing atmosphere, for example in a vacuum, an inert gas, hydrogen, etc. The reducing atmosphere may be at a pressure of about 10 Torr to about 2000 Torr in some embodiments from about 100 Torr to about 1000 Torr, and in some embodiments from about 100 Torr to about 930 Torr. Mixtures of hydrogen and other gases (eg, argon or nitrogen) may also be used. When used, the lamellar particles may be better able to withstand the high sintering temperatures and extended sintering times often used in the formation of the planar anode, and to produce a porous sintered body with low shrinkage and a large specific surface area.
[0011] Under the effect of sintering, the pellet shrinks due to the growth of metallurgical bonds between the particles. Since shrinkage generally increases the pellet density, lower ("green") press densities can be used to still achieve the desired target density. For example, the target density of the pellet after sintering is typically from about 5 to about 8 grams per cubic centimeter. As a result of the retraction phenomenon, however, it is not necessary to squeeze the pellet to such densities, but it can instead be squeezed at densities of less than about 6.0 grams per cubic centimeter, and some embodiments, from about 4.5 to about 5.5 per cubic centimeter. Among other things, the ability to use lower green densities can provide significant savings and can increase treatment efficiency. It should be understood that the pressing density may not always be uniform across the base, particularly if the compression occurs in a direction perpendicular to the longitudinal axis of the wire. Precisely, the pressing density is determined by dividing the amount of material by the volume of the compressed pellet. The volume of the pellet is directly proportional to the length compressed in the direction perpendicular to the longitudinal axis of the wire. The density is inversely proportional to the compressed length. Thus, the compressed length is actually less than the locations adjacent to the wire relative to the remaining pellet locations. The pressing density is in the same way greater than those locations adjacent to the wire. For example, the pellet density at these locations adjacent the yarn is typically at least about 10% greater, and in some cases at least about 20% greater than the pellet pressing density at the remaining pellet locations. Referring to FIGS. 2 and 3, for example, an embodiment of a planar anode 200 is provided which contains anode wire 220. The anode wire extends in a longitudinal direction (direction 25 "y") from the anode 200. In order to integrate the anode wire 220 into the planar anode 200, a press die may be partially filled with the powder, and then an anode wire may be inserted into the press matrix. After this, the mold can be filled with powder and the entire assembly can be pressed into a pellet.
[0012] The resulting planar anode may have a small overall thickness compared to its overall length and overall width to improve electrical performance and volumetric efficiency of the resulting capacitor. Referring to FIG. 2, for example, the length "L" represents the total length of the anode 200 from a first end 60 to a second end 62. In some cases, the length "L" of the anode 200 may be in the range of from about 1 millimeter to about 80 millimeters, for example from about 10 millimeters to about 60 millimeters, for example from about 20 millimeters to about 50 millimeters. However, if reference is also made to FIG. 2, the width "W" of the anode 15 may also be from about 0.5 millimeters to about 60 millimeters, for example from about 1 millimeter to about 40 millimeters for example from about 5 millimeters to about 30 millimeters. In addition, referring to Figure 3, typically, the thickness "H" of the anode is about 5 millimeters or less, for example about 0.05 millimeters to about 4 millimeters, for example from about 0.1 millimeter to about 3.5 millimeters, for example from about 0.2 millimeters to about 2 millimeters. Generally, in some embodiments, the ratio of the length "L" of the anode to the thickness "H" of the planar anode may be in the range of about 5 to about 50, in some embodiments. from about 6 to about 40, and in some embodiments, from about 7 to about 30. In addition, the ratio of width "W" of the anode to thickness 3028659 "H" The anode may range from about 4 to about 35, in some embodiments from about 5 to about 25, and in some embodiments from about 6 to about 20.
[0013] In addition, although the planar anode is shown having a "D-shape" in Fig. 2, it should also be understood that the planar anode must have any other desired shape, for example square, rectangular, circular, oval, triangular, etc.
[0014] Polygonal shapes having more than four (4) sides (e.g., hexagon, octagon, heptagon, pentagon, etc.) may be particularly desired because of their relatively high surface area. Further, referring to Figs. 1 and 4, for example, an embodiment of a capacitor 10 is shown which includes the planar anode 200 shown in Figs. 2 and 3. Although only one Plane anode is presented, it should be understood that multiple anodes (eg, a stack) can be used as described, for example, in US Patent No. 7,483,260 issued to Ziarniak et al. Further, regardless of the particular geometry of the planar anode, the planar anode also contains a dielectric formed by anodic oxidation ("anodizing") of the sintered anode so that a dielectric layer is formed on and / or inside the plane anode. For example, a tantalum anode (Ta) may be anodized to tantalum pentoxide (Ta2O5). Typically, the anodization is carried out by initial application of a solution to the anode, for example by immersing the anode in the electrolyte. Aqueous solvents (e.g., water) and / or non-aqueous solvents (e.g., ethylene glycol) can be used. To improve the conductivity, a compound can be used which is capable of dissociating the solvent to form ions. Examples of these compounds include, for example, acids, such as those described below with respect to the electrolyte. For example, an acid (e.g., phosphoric acid) may comprise from about 0.01% by weight to about 5% by weight, in some embodiments from about 0.05% by weight to about 0% by weight. , 8% by weight, and in some embodiments from about 0.1% by weight to about 0.5% by weight of the anodizing solution. If desired, mixtures of acids may also be used. A current is passed through the anodizing solution to form a dielectric layer. The value of the forming voltage determines the thickness of the dielectric layer. For example, the power supply can initially be set to a galvanostatic mode until the required voltage is reached. After this, the power supply can switch to a potentiostatic mode to ensure that the desired dielectric thickness is formed over the entire surface of the anode. Of course, other known methods may also be employed, such as pulse or step potentiostatic methods. The temperature of the anodizing solution may be in the range of about 10 ° C to about 200 ° C, in some embodiments from about 20 ° C to about 150 ° C, and in some embodiments From about 30 ° C to about 100 ° C. The resulting dielectric layer may be formed on a surface of the anode and within its pores. When used, the specific nature of the powder may allow the resulting anode to achieve a high specific charge even at the high forming voltages often used in the present invention. For example, within the ranges noted above, the anode may remain capable of a specific charge of from about 2000 pf * V / g to about 20,000 pF * V / g, in some embodiments. from about 5,000 pF * V / g to about 15,000 pF * V / g or higher, and in some embodiments from about 8,000 to about 12,000 pF * V / g.
[0015] III. Cathode In addition to the sealing assembly and the planar anode, a cathode is also used in the capacitor which can be constructed using any of a variety of techniques. In one embodiment, the cathode contains a metal substrate, which may include any metal, such as tantalum, niobium, aluminum, nickel, hafnium, titanium, copper, silver, steel (eg, stainless), alloys thereof (e.g., electroconductive oxides), composites thereof (e.g., an electroconductive oxide-coated metal), and so forth, which is coated with an electrochemically active material. Titanium and tantalum, as well as their alloys, are particularly suitable for use in the present invention. The geometrical configuration of the substrate can generally vary as known to those skilled in the art, for example in the form of a container, a bottle, an aluminum foil, a sheet, a screen. , a lattice, etc. Although not necessary, in one embodiment, for example, the metal substrate may form the capacitor housing in which the planar anode is disclosed, and such a housing may be D-shaped or otherwise form which generally corresponds to the shape of the planar anode. For example, it should be understood that any geometric configuration can be used in the present invention, for example cylindrical, rectangular, triangular, prismatic, etc.
[0016] The substrate may be roughened to increase its surface area and increase the degree of adhesion of the electrochemically active material thereto. In one embodiment, for example, the surface is chemically etched, for example by applying a solution of a corrosive substance (e.g., hydrochloric acid) to the surface. The surface may also be electrochemically etched, for example by applying a voltage to a solution of the corrosive substance such that it undergoes electrolysis. The voltage can be raised to a high enough level to initiate "sparking" on the surface of the substrate, which is believed to create local surface temperatures high enough to corrode the substrate. This technique is described in more detail in U.S. Patent No. 8,279,585 to Dreissig, et al., To which the reader can refer. In addition to electrochemical and chemical roughening techniques, mechanical roughening can also be used. In one embodiment, for example, the surface of the metal substrate may be abrasive blasted by propelling a stream of abrasive media (eg, sand) against at least a portion of its surface. An electrochemically active material may also be applied to the cathode substrate to inhibit corrosion and act as a thermal barrier in the event of an increase in voltage. The electrochemically active material may be formed from one or more layers. The material used in such a layer (such layers) may vary. Any of a variety of known electrochemically active materials may be generally used. Suitable material is a conductive polymer, such as those with n conjugation and which have electrical conductivity after oxidation or reduction (e.g., electrical conductivity of at least about 1 μS cm -1 after oxidation). Examples of such n-conjugated conductive polymers include, for example, polyheterocycles (e.g., polypyrroles, polythiophenes, polyanilines, etc.), polyacetylenes, poly-p-phenylenes, polyphenolates, and so on. The substituted polythiophenes are particularly suitable for use as conductive polymers in that they exhibit particularly good mechanical strength and electrical performance. Without wishing to be bound by theory, it is believed that charging the capacitor at a high voltage (e.g., greater than the forming voltage) forces the electrolyte ions into the coatings containing these substituted polythiophenes. This causes "swelling" of the conductive polymer and holds the ions near the surface, thereby improving the charge density. Since the polymer is generally amorphous and non-crystalline, it can also dissipate and / or absorb the heat associated with the high voltage. During the discharge, it is also assumed that the polythiophene "loosens" and allows ions in the electrolyte to move out of the coating. By this mechanism of swelling and relaxation, the charge density near the metal substrate can be increased without chemical reaction with the electrolyte. As a result, mechanical strength and good electrical performance can be provided without the need for conventional conductive coatings, such as those made from activated carbon or metal oxides (for example, ruthenium oxide). . In fact, excellent results can be obtained by using the coating as the main material on the metal substrate. In other words, the coating may comprise at least about 90% by weight, in some embodiments at least about 92% by weight, and in some embodiments at least about 95% by weight of the materials) present on the metal substrate. Nevertheless, it should be understood that other conductive coatings may also be used in some embodiments of the present invention.
[0017] In a particular embodiment, the substituted polythiophene has the following general structure: wherein T is 0 or S; D is an optionally substituted (C1-C5) alkylene radical (for example, methylene, ethylene, n-propylene, n-butylene, n-pentylene, etc.); R7 is a linear or branched, optionally substituted C1-C18 alkyl radical (for example methyl, ethyl, n- or iso-propyl, n-, iso-, sec- or tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2-dimethylpropyl, n-hexyl, n-heptyl, n-octyl, 2-ethylhexyl, n-nonyl, n decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-hexadecyl, n-octadecyl, etc.); an optionally substituted C5-C12 cycloalkyl radical (e.g., cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, etc.); an optionally substituted C6-C14 aryl radical (e.g., phenyl, naphthyl, etc.); an optionally substituted C7-C18 aralkyl radical (e.g., benzyl, o-, m-, p-tolyl, 2,3-, 2,4-, 2,5-, 2-6, 3-4- 3,5-xylyl, mesityl, etc.); an optionally substituted C1-C4 hydroxyalkyl radical, or a hydroxyl radical; and q is an integer of 0 to 8, in some embodiments 0 to 2, and in one embodiment 0; and n is from 2 to 5,000, in some embodiments from 4 to 2,000, and in some embodiments from 5 to 1,000. Examples of substituents for radicals "D" or "R7" include, for example, For example, alkyl, cycloalkyl, aryl, aralkyl, alkoxy, halogen, ether, thioether, disulfide, sulfoxide, sulfone, sulfonate, amino, aldehyde, keto, carboxylic acid ester, carboxylic acid, carbonate, carboxylate, cyano alkylsilane and alkoxysilane, carboxylamide, and so on. Particularly suitable thiophene polymers are those in which "D" is an optionally substituted C2 to C3 alkylene radical. For example, the polymer may be optionally substituted with poly (3,4-ethylenedioxythiophene), which has the following general structure: (R7) Processes for forming the conductive polymers, as described above, are well known in the art. For example, U.S. Patent No. 6,987,663 to Merker, et al. describes various techniques for forming substituted polythiophenes from a monomeric precursor. The monomeric precursor may, for example, have the following structure: wherein T, D, R7, and q are defined above. Particularly suitable thiophene monomers are those in which "D" is an optionally substituted C2 to C3 alkylene radical. For example, optionally substituted 3,4-alkylenedioxythiophenes may be used which have the following general structure: ## STR2 ## wherein R 7 and q are as defined above. In a particular embodiment, "q" is 0. A commercially available example of 3,4-ethylenedioxythiophene is available from Heraeus Clevios under the designation Clevios ™ M. Other suitable monomers are also described in US Pat. No. 5,111,327 issued to Blohm, et al. and 6,635,729 issued to Groenendaal, et al. Derivatives of these monomers may also be used which are, for example, dimers or trimers of the aforementioned monomers. Higher molecular derivatives, in other words, tetramers, pentamers, etc. Monomers are suitable for use in the present invention. The derivatives may consist of identical or different monomeric units and used in pure form and in a mixture with each other and / or with the monomers. Oxidized or reduced forms of these precursors may also be used. The thiophene monomers can be chemically polymerized in the presence of an oxidation catalyst. The oxidation catalyst typically comprises a transition metal cation, such as iron (III), copper (II), chromium (VI), cerium (IV), manganese (IV), manganese (VII), 3028659 ruthenium (III), etc. A dopant may also be used to provide excess charge over the conductive polymer and stabilize the conductivity of the polymer. The dopant typically comprises an inorganic or organic anion, such as an ion of a sulfonic acid. In some embodiments, the oxidation catalyst used in the precursor solution has both catalytic and dopant functionality in that it comprises a cation (e.g., a transition metal) and an anion (e.g. sulfonic acid). For example, the oxidation catalyst may be a transition metal salt that includes iron (III) cations, such as iron (III) halides (e.g., FeCl3) or iron (III) salts. and other inorganic acids, such as Fe (C104) 3 or Fe2 (SO4) 3 and iron (III) salts of organic acids and inorganic acids including organic radicals. Examples of the iron (III) salts of inorganic acids with organic radicals include, for example, iron (III) salts of monoesters of sulfuric acid of C 1 -C 20 alkanols (e.g. iron (III) lauryl sulphate). Similarly, examples of iron (III) salts of organic acids include, for example, iron (III) salts of C1-C20 alkane sulfonic acids (eg methane, ethane, propane). butane, or dodecane sulfonic acid); iron (III) salts of perfluorosulfonic aliphatic acids (e.g., trifluoromethanesulfonic acid, perfluorobutane sulfonic acid, or perfluorooctane sulfonic acid); The iron (III) salts of C1 to C20 aliphatic carboxylic acids (for example 2-ethylhexylcarboxylic acid); iron (III) salts of aliphatic perfluorocarboxylic acids (e.g., trifluoroacetic acid or perfluorooctane acid); iron (III) salts of aromatic sulfonic acids optionally substituted with C 1 -C 20 alkyl groups (for example, benzene sulfonic acid, o-toluenesulfonic acid, p-toluene sulfonic acid, or dodecylbenzene sulphonic acid); iron (III) salts of cycloalkanesulphonic acids (e.g., camphorsulfonic acid); And so on. Mixtures of these aforementioned iron (III) salts can also be used. Iron (III) -p-toluene sulfonate, iron (III) -o-toluene sulfonate, and mixtures thereof are particularly suitable. A commercially available example of iron (III) -p-toluene sulfonate is available from Heraeus Clevios as Clevios ™ 20 C. Various methods can be used to form a conductive polymer layer. In one embodiment, the oxidation catalyst and the monomer are applied, sequentially or at the same time, so that the polymerization reaction occurs in situ on the substrate. Suitable application techniques may include screen printing, dipping, electrophoretic coating, and sputtering, and may be used to form a conductive polymer coating. As one example, the monomer may initially be mixed with the oxidation catalyst to form a precursor solution. Once the mixture is formed, it can be applied to the substrate and then allowed to polymerize so that the conductive coating is formed on the surface. Alternatively, the oxidation catalyst and the monomer may be applied sequentially. In one embodiment, for example, the oxidation catalyst is dissolved in an organic solvent (eg, butanol) before being applied as an immersion solution. The substrate can then be dried to remove the solvent therefrom. After this, the substrate may be immersed in a solution containing the monomer. Polymerization is typically carried out at temperatures of about -10 ° C to about 250 ° C, and in some embodiments, from about 0 ° C to about 200 ° C, depending on the oxidizing agent. used and the desired reaction time. Suitable polymerization techniques as described above can be described in more detail in US Patent No. 7,515,396 to Biler. Other methods of applying this conductive coating (s) can be described in US Pat. Nos. 5,457,862 issued to Sakata, et al., 5,473,503 issued to Sakata, et al. , 5,729,428 issued to Sakata, et al., And 5,812,367 issued to Kudoh, et al. In addition to in situ application, a conductive polymer layer may also be applied as a dispersion of conductive polymer particles. Although their size may vary, it is typically desired that the particles have a small diameter to increase the available surface area for adhering to the substrate. For example, the particles may have an average diameter of about 1 to about 500 nanometers, in some embodiments from about 5 to about 400 nanometers, and in some embodiments, from about 10 to about 300 nanometers. The D90 value of the particles (the particles having a diameter less than or equal to the D90 value constituting 90% of the total volume of all solid particles) can be about 10 micrometers or less, in embodiments of about 10 microns or less, and in some embodiments, from about 1 nanometer to about 8 microns. The particle diameter can be determined using known techniques, such as ultracentrifugation, laser diffraction, etc. If desired, one or more of the application steps described above may be repeated until the desired thickness of the coating is reached. In some embodiments, only a relatively thin layer of the coating is formed at a time. The total target thickness of the coating may generally vary depending on the desired properties of the capacitor. Typically, the resultant conductive polymer coating has a thickness of about 0.2 micrometer ("pm") to about 50 pm, in some embodiments from about 0.5 pm to about 20 pm, and in some embodiments of the present invention. from about 1 μm to about 5 μm. It should be understood that the thickness of the coating is not necessarily the same at all locations on the substrate. Nevertheless, the average thickness of the coating on the substrate is generally in the ranges noted above. The conductive polymer layer may optionally be healed. Healing may occur after each application of an entire polymer coating layer. In some embodiments, the conductive polymer may be the embodiment of the conductor-scarred embodiment or may occur after immersion of the portion in an electrolytic solution, followed by application of a constant voltage to the solution until the current is reached. be reduced to a preselected level. If desired, such healing can be accompanied by multiple steps. For example, an electrolytic solution may be a dilute solution of the monomer, catalyst, and dopant in an alcoholic solvent (eg, ethanol). The coating may also be washed if desired to remove various intermediates, excess reactants, and so on.
[0018] IV. Working Electrolyte The capacitor also comprises a working electrolyte (not shown) which can generally be in the form of a liquid, for example a solution (for example, aqueous or non-aqueous), a dispersion, a gel, etc. The working electrolyte is disposed within the housing and is the electrically active material that provides the path of connection between the anode and the cathode 30 planes. If desired, the planar anode may be initially impregnated with an electrolyte (not shown) 3028659 before being positioned within a housing (discussed above). The electrolyte may also be added to the capacitor at a later stage of production. Various suitable electrolytes are disclosed in U.S. Patent Nos. 5,369,547 and 6,594,140 issued to Evans, et al., To which the reader may refer. Typically, the electrolyte is ionically conductive in that it has an ionic conductivity of from about 1 to about 100 milliSiemens per centimeter ("mS / cm"), in some embodiments from about 5 to about 80 mS / cm. cm, in some embodiments from about 15 mS / cm to about 70 mS / cm, and in some embodiments from about 20 to about 60 mS / cm, determined at a temperature of 25 ° C using a conductivity meter (for example, Oakton Con Series 11). Within the ranges noted, the electric field is as strong as the dielectric but it can extend into the electrolyte to a certain length (Debye length) sufficient to result in significant charge separation. This extends the potential energy of the dielectric to the electrolyte so that the resulting capacitor is able to store even more potential energy than is predicted by the thickness of the dielectric. In other words, the capacitor can be charged to a voltage that is close to or higher than the dielectric forming voltage. The ratio of the voltage at which the capacitor may be charged to the forming voltage may, for example, be from about 0.80 to about 2.00, and in some embodiments, about 0, 85 to about 1.50, and in some embodiments, about 0.86 to about 1.20. As an example, the voltage at which the capacitor is charged can be from about 150 volts to about 300 volts, in some embodiments from about 180 volts to about 260 volts, and in some embodiments, about 200 volts at about 240 volts. The forming voltage may similarly be in the range of about 180 volts to about 320 volts, in some embodiments from about 200 volts to about 280 volts, and in some embodiments about 220 volts at about 250 volts. The working electrolyte is also relatively neutral and has a pH value of about 4.5 to about 8.0, in some embodiments from about 5.0 to about 7.5, in some embodiments. from about 5.5 to about 7.0, in some embodiments from about 6.0 to about 6.5. Among other things, such a pH can improve the ability of hydrogen ions present in an aqueous electrolyte to interact with the cathode material to achieve maximum capacitance and thus maximum energy density. The desired ionic conductivity can be achieved by selecting the ionic compound (s) (eg, acids, bases, salts, and so on) with certain concentration ranges. In a particular embodiment, the weak organic acid salts can be effective to obtain the desired conductivity of the electrolyte. The cation of the salt may comprise monoatomic cations, for example alkali metals (e.g., Li +, Na +, K +, Rb +, or Cs +), alkaline earth metals (e.g., Be2 +, Mg2 +, Ca2 +, Sr2 + or Ba2 +), transition metals (eg, Ag +, Fe2 +, Fe2 +, etc.), as well as polyatomic cations, such as NH4. Monovalent ammonium (NHe), sodium (K +), and lithium (LiI are particularly suitable cations for use in the present invention.) The organic acid used to form the salt anion is "weak" in weight. wherein it typically has a first acid dissociation constant (pK, I) of from about 0 to about 11, in some embodiments from about 1 to about 10, and in some embodiments, from about 2 to about 10, determined at 25 ° C. Any suitable weak organic acid can be used in the present invention, for example, carboxylic acids, such as acrylic acid, methacrylic acid, malonic acid, succinic acid, salicylic acid, sulfosalicylic acid, adipic acid, maleic acid, malic acid, oleic acid, gallic acid, tartaric acid (e.g. deototartaric acid, mesotartaric acid, etc.), citric acid, formic acid, acetic acid, glycolic acid, oxalic acid, propionic acid, phthalic acid, isophthalic acid, glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, itaconic acid, trifluoroacetic acid, barbituric acid, cinnamic acid, benzoic acid, 4-hydroxybenzoic acid, aminobenzoic acid, and the like. ; mixtures of these, and so on. The polyprotic acids (e.g., diprotic, triprotic, etc.) are particularly desirable for their use in salt formation, such as adipic acid (pKai of 4.43 and pI, of 5.41). , α-tartaric acid (pKai of 2.98 and μl ", 2 of 4.34), meso-tartaric acid (pKai of 3.22 and pI, of 4.82), oxalic acid (pKai of 1.23 and pI <", 2 of 4.19), lactic acid (pKai of 3.13 and p1, of 2.76 and p1, 3 of 6 , 40), etc.
[0019] While the actual amounts may vary depending on the particular salt used, its solubility in the solvent (s) used in the electrolyte, and the presence of other components, these acid salts The low organic compounds are typically present in the electrolyte in an amount of from about 0.1 to about 40 percent by weight, in some embodiments from about 0.2 to about 35 percent by weight, in some embodiments. from about 0.3 to about 30% by weight, and in some embodiments from about 0.5 to about 25% by weight. The electrolyte is typically aqueous in that it contains an aqueous solvent, such as water (e.g., deionized water). For example, water (e.g., deionized water) may comprise from about 20% by weight to about 95% by weight, in some embodiments from about 30% by weight to about 90% by weight. and in some embodiments from about 40% by weight to about 85% by weight of the electrolyte. A secondary solvent may also be used to form a solvent mixture. Secondary solvents may include, for example, glycols (eg, ethylene glycol, propylene glycol, butylene glycol, triethylene glycol, hexylene glycol, polyethylene glycols, ethoxydiglycol, dipropylene glycol, etc.). ); glycol ethers (e.g., methyl glycol ether, ethyl glycol ether, isopropyl glycol ether, etc.); alcohols (e.g., methanol, ethanol, n-propanol, isopropanol, and butanol); ketones (e.g., acetone, methyl ethyl ketone, and methyl isobutyl ketone); esters (e.g., ethyl acetate, butyl acetate, diethylene glycol ether acetate, methoxypropyl acetate, ethylene carbonate, propylene carbonate, etc.) ; amides (for example, dimethylformamide, dimethylacetamide, dimethylcaprylic / capric fatty acid amide and Nalkylpyrrolidones); sulfoxides or sulfones (for example, dimethylsulfoxide (DMSO) and sulfolane); And so on. These mixtures typically contain water in an amount of from about 40% by weight to about 80% by weight, in some embodiments from about 50% by weight to about 75% by weight, and in some embodiments of the present invention. from about 60% by weight to about 70% by weight of the solvent system and secondary solvents in an amount of about 20% by weight to 60% by weight, in some embodiments about 25% by weight to about 50% by weight, and in some embodiments from about 30% by weight to about 40% by weight of the solvent system. Similarly, when these mixtures are used, water typically constitutes from about 30% by weight to about 70% by weight, in some embodiments from about 35% by weight to about 65% by weight, and in some embodiments, from about 40% by weight to about 60% by weight of the electrolyte and the secondary solvents may comprise from about 5% by weight to about 40% by weight, in some embodiments of the present invention. from about 10% by weight to about 35% by weight, and in some embodiments from about 15% by weight to about 30% by weight of the electrolyte. One or more acids or pH adjusting agents can also be used to help achieve the desired pH and conductivity values. Suitable acids may include, for example, inorganic acids, such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, polyphosphoric acid, boric acid, boronic acid etc. ; organic acids, including carboxylic acids, such as acrylic acid, methacrylic acid, malonic acid, succinic acid, salicylic acid, sulfosalicylic acid, adipic acid, maleic acid, malic acid, oleic acid, gallic acid, tartaric acid, citric acid, formic acid, acetic acid, ethylenediaminetetraacetic acid ("EDTA"), glycolic acid, oxalic acid, propionic acid, phthalic acid, isophthalic acid, glutaric acid, gluconic acid, lactic acid, aspartic acid, glutamic acid, itaconic acid, trifluoroacetic acid, barbituric acid, cinnamic acid, benzoic acid, 4-hydroxybenzoic acid, aminobenzoic acid, and the like. ; sulfonic acids, such as methanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfonic acid, styrenesulfonic acid, naphthalenesulphonic acid, hydroxybenzenesulphonic acid, and the like. ; polymeric acids, such as poly (acrylic acid) or poly (methacrylic acid) and copolymers thereof (e.g., maleic-acrylic, sulfonic-acrylic, and styrene-acrylic copolymers), carrageenic acid, carboxymethyl cellulose, alginic acid, etc. ; And so on. EDTA may be particularly suitable when a gelled electrolyte is used since it can not only reduce the pH value of the electrolyte, but also serve as a sequestering agent for any metallic impurity that may be present in the electrolyte. particles.
[0020] Although the total concentration of acids may vary, these are typically present in an amount of from about 0.01% by weight to about 10% by weight, in some embodiments of about 0.05% by weight. at about 5% by weight, and in some embodiments, from about 0.1% by weight to about 2% by weight of the electrolyte. In a particular embodiment, a mixture of different acids may be used, for example a mixture of an inorganic acid and an organic acid. In these embodiments, the inorganic acids (e.g., phosphoric acid) can be from about 0.005 wt% to about 5 wt%, in some embodiments about 0.01 wt%. from about 0.05% by weight to about 1% by weight of the electrolyte, and organic acids (eg, EDTA) may be in the same way, from about 0.005% by weight to about 5% by weight, in some embodiments from about 0.01% by weight to about 3% by weight, and in some embodiments from about 0.05% by weight to about 1% by weight of the electrolyte. The electrolyte may also contain other components that help improve the electrical performance of the capacitor. For example, a depolarizer may be used in the electrolyte to help inhibit the evolution of hydrogen gas at the cathode of the electrolytic capacitor, which could otherwise result in swelling of the capacitor and eventually failure. When used, the depolarizer is normally from about 1 to about 500 parts per million ("ppm"), in some embodiments from about 10 to about 200 ppm, and in some embodiments, about 20 ppm to about 150 ppm of the electrolyte.
[0021] For example, depolarizers typically comprise from about 0.01% by weight to about 5% by weight, in some embodiments from about 0.05% by weight to about 2% by weight, and in some embodiments from about 0.1% by weight to about 1% by weight of the electrolyte.
[0022] Suitable depolarizers may include nitroaromatic compounds, for example 2-nitrophenol, 3-nitrophenol, 4-nitrophenol, 2-nitrobenzonic acid, 3-nitrobenzonic acid, 4-nitrobenzonic acid, 2-nitrophenol, nitroacetophenone, 3-nitroacetophenone, 4-nitroacetophenone, 2-nitroanisole, 3-nitroanisole, 4-nitroanisole, 2-nitrobenzaldehyde, 3-nitrobenzaldehyde, 4-nitrobenzaldehyde, 2-nitrobenzyl alcohol, 3-nitrobenzyl alcohol, 4-nitrobenzyl alcohol, 2-nitrophthalic acid, 3-nitrophthalic acid, 4-nitrophthalic acid, and so on. Nitroaromatic depolarizers particularly suitable for use in the present invention are nitrobenzoic acids, their anhydrides or salts, substituted with one or more alkyl groups (eg, methyl, ethyl, propyl, butyl, etc.). Specific examples of these alkyl-substituted nitrobenzoic compounds include, for example, 2-methyl-3-nitrobenzoic acid; 2-methyl-6-nitrobenzoic acid; 3-methyl-2-nitrobenzoic acid; 3-methyl-4-nitrobenzoic acid; 3-methyl-6-nitrobenzoic acid; 4-methyl-3-nitrobenzoic acid; their anhydrides or their salts; And so on.
[0023] In a particular embodiment, the working electrolyte may be in the form of a viscoelastic "gel", which is generally defined as a solid or semisolid colloidal suspension which contains a continuous phase and a dispersed phase, at least one of the phases being a solid and at least one of the phases being a liquid. For example, a hydrogel can be formed when the inorganic oxide particles are crosslinked to form a continuous phase and the solvent contains water in the form of a dispersed phase which is trapped within the network. reticle. Regardless of its exact form, the viscoelastic gel inside the capacitor is in the form of a semi-solid or a solid so that it does not flow easily at room temperature. This property can be represented by the viscoelastic phase angle δ, which is the degree to which the sinusoidal variation in time of the stress is out of phase with respect to the sinusoidal variation in time of the shear rate. The phase angle for an ideal elastic solid is 0 ° (in phase) and the phase angle for an ideal viscous liquid is 90 ° (out of phase). In the present invention, the gelled electrolyte typically has a phase angle of from 0 ° to about 20 °, in some embodiments from about 0.1 ° to about 5 °, and in some embodiments from about 0.2 ° to about 2 °. Another parameter that can represent the viscoelastic behavior of the gel is the storage modulus, G ', which is determined by dividing the "in-phase" component of the stress (representing the solid-type behavior) by the maximum strain. Typically, the gel electrolyte of the present invention has a storage module of about 5 kilopascals ("kPa") or more, in embodiments of about 10 kPa or more, and in some embodiments of about 15 to about 50 kPa.
[0024] The phase angle and storage modulus can be determined at room temperature (eg, 25 ° C) by a dynamic oscillatory test (e.g., a frequency of 10 Hz and a pressure of 5 Pa) with a rheometer. having a cone-plate configuration. To achieve the combination of high conductivity and neutral pH value, the gelled working electrolyte may contain a combination of the weak organic acid salt, the solvent system, and the adjusting agent. the pH (acid) discussed above together with the inorganic oxide particles to help achieve the desired viscosity and electrical properties for the capacitor. The amount of inorganic oxide particles in the electrolyte may vary depending on the degree of gelation required, as well as the particular nature and concentration of the other components in the electrolyte. Typically, however, the inorganic oxide particles comprise from about 0.5% by weight to about 20% by weight, in some embodiments from about 1% by weight to about 15% by weight, and in some embodiments embodiments, from about 1.5% by weight to about 10% by weight of the electrolyte.
[0025] The particles may have different shapes, configurations and sizes depending on the desired result. For example, the particles may be in the form of a sphere, a crystal, a stick, a disc, a tube, a string, etc. The average particle size may be less than about 1000 nanometers, in some embodiments from about 1 to about 500 nanometers, in some embodiments from about 2 to about 200 nanometers, and in some embodiments embodiment, from about 4 to about 50 nanometers. As used herein, the average size of a particle refers to its average length, average width, average height, and / or average diameter. The particles also typically have a large specific surface area, e.g. from about 50 square meters per gram (m 2 / g) to about 1000 m 2 / g, in some embodiments from about 100 m 2 / g to about 600 m 2 / g, and in some embodiments, from about 150 m 2 / g to about 400 m 2 / g. The term "specific surface area" generally refers to the surface area as determined by Brunauer's physical gas adsorption (B.E.T.) method, Emmet, and Teller, Journal of the American Chemical Society, Vol. 60, 1938, p. 309, with nitrogen as an adsorption gas. The assay can be performed with a MONOSORB® specific surface area analyzer available from QUANTACHROME Corporation, Syosset, NY, which measures the amount of adsorbed nitrogen gas adsorbed to a solid surface by detecting the conductivity change. A flow mixture of adsorbate and inert carrier gas (eg, helium). In addition, the particles may also be relatively non-porous or solid. In other words, the particles may have a pore volume which is less than about 0.5 milliliters per gram (mL / g), in some embodiments less than about 0.4 milliliters per gram, in some embodiments less than about 0.3 mL / g, and in some embodiments, about 0.2 mL / g to about 0.3 mL / g. Without wishing to be bound by theory, it is believed that particles having a small size, a large surface area, and a solid nature can improve the rate of gelation and improve the uniformity and stability of the suspension obtained. The inorganic oxide particles can be formed from a variety of materials, including, but not limited to, silica, alumina, zirconia, magnesium oxide, titanium dioxide, iron, zinc oxide, copper oxide, etc., as well as combinations thereof. The particles can also be formed using a pyrogenic process, precipitation, etc. Because of their larger surface area and smaller particle size, however, the smoked particles are particularly suitable for use in the present invention. The fumed silica, for example, is amorphous SiO 2 which can be produced by vapor phase hydrolysis of silicon tetrachloride in a hydrogen-oxygen flame. The three-dimensional branched chain aggregates are produced in the flame from the melting of primary particles. During cooling, these aggregates agglomerate into a fine powder having a particle size within the ranges proposed above. The fumed silica has silanol groups which can react under acidic conditions to form a crosslinked network. The siloxane crosslink obtained is a silicon and oxygen compound in which each silicon atom is bonded to four oxygen atoms, forming a tetrahedral structure, in a manner analogous to the carbon to hydrogen bonding. in methane, the bonds having about the same resistance in each case. This structure is found in dioxide and in silicates in general, where SiO4 groups occur in chains or rings. By creating siloxane bonds, a gel is formed which traps the liquid phase of the electrolyte. Commercially available fumed silica particles may, for example, include those available from Cabot Corporation as CAB-0-SILO.
[0026] The working electrolyte components may be combined with each other in a variety of different ways, before and / or after incorporation into the capacitor. In a particular embodiment, the electrolyte can be gelled before being placed in contact with the anode and / or the cathode (discussed below). For example, when the electrolyte components are initially combined with each other, the electrolyte may be in the form of a sol which contains particles in the form of a dispersed phase. However, these soils can be catalyzed to induce gelation by several methods. Examples include adjusting pH and / or soil temperature to a point where gelation occurs. Alternatively, the sol may be subjected to a regulated form of energy (eg, thermal, ultrasound, ultraviolet light, electron beam radiation, etc.) to induce gelation. The use of ultrasonic energy (e.g., ultrasound probes) is particularly desirable since it minimizes the need to change the pH or temperature of the electrolyte. The electrolyte can be incorporated into the capacitor in a variety of different ways. In one embodiment, for example, the electrolyte 10 is simply added to the capacitor after positioning the anode and the cathode in the desired configuration. This can be achieved, for example, by using a fill port. The anode may also be pre-impregnated with the electrolyte, for example by immersing the anode in the electrolyte before placing it in the capacitor. Impregnation of the anode with the electrolyte can further improve the degree of contact between the anode and the electrolyte. In either case, the electrolyte may have a low initial viscosity and a low flowability so that it can be precisely incorporated into the capacitor. For example, when in the form of a gel, the electrolyte may have an initial viscosity (e.g., 1 hour or less after initiation of gelation) in the range of about 1 to about 40 in some embodiments from about 2 to about 30 centipoise, and in some embodiments from about 3 to about 10 centipoise, as determined using a Brookfield LVT viscometer (spindle * 3). at 60 rpm) at a temperature of 25 ° C.
[0027] In the same manner, the gel may have an initial phase angle of about 50 ° to 90 °, in some embodiments from about 60 ° to 90 °, and in some embodiments, from about 80 ° to about 90 °. At 90 °, as well as an initial storage module G 'of about 1 kilopascal or less, in embodiments of about 0.1 kilopascal or less, and in some embodiments, from about 0 to about 0.01 kilopascal. After incorporation into the capacitor, however, gelation of the electrolyte may continue until the viscosity increases, for example to viscosity, phase angle 5, and / or storage module G 'within the target ranges specified above. This "semi-solid" or "solid" transition may occur relatively after the induction of gelation, for example from about 1 to 100 hours, in some embodiments from about 10 to about 80 hours, and some embodiments, from about 20 to about 60 hours. The transition can also occur before and / or after the incorporation of the anode into the capacitor and its contact with the cathode. If desired, a suitable additional "fill" electrolyte may be added to ensure that good electrical contact exists between the impregnated anode and the cathode. This filling electrolyte can be formed according to the present invention, or it can be formed from other known components.
[0028] Regardless of the particular characteristics of the sealing assembly, the planar anode, the cathode, and the working electrolyte, the planar anode 200 and the other components are generally positioned inside the sealing assembly. a housing 12, a part of which may also serve as a cathode for the capacitor. In addition, an electrochemically active material (not shown) may be applied to at least a portion of the housing 12 to inhibit corrosion and also act as a thermal barrier in the event of an increase in voltage. In one embodiment, at least a portion of the housing 12 is generally formed of metal, which may include any metal, such as tantalum, niobium, aluminum, nickel, hafnium, titanium, copper, silver, steel (e.g., stainless), alloys thereof (e.g., electroconductive oxides), composites thereof (e.g., an electroconductive oxide-coated metal), and so on, which is coated with an electrochemically active material (cathode). Titanium and tantalum, as well as their alloys, are particularly suitable for use in the present invention. In other embodiments, a portion of the housing may be formed of a non-metallic material. The geometrical configuration of the substrate may generally vary as known to those skilled in the art, for example in the form of a container, a housing, an aluminum foil, a sheet, a screen, a lattice, etc. In one embodiment, for example, the metal substrate forms a planar housing having a shape of D. It should be understood, however, that any geometric configuration may be used in the present invention, for example square, circular, rectangular, triangular, prismatic, etc. The housing may also include a cover that covers the anode and the electrolyte, which may be formed from the same material as the housing or a different material. Regardless of the particular characteristics of the housing and whether or not it optionally includes the electrochemically active cathode material of the present invention, the particular manner in which the anode is incorporated into the housing can be accomplished using a variety of techniques. . As shown in FIG. 4, the anode 200 may be positioned within the housing 12 consisting of a first housing member 14 and a second housing member 16. The first housing member 14 may have a front wall 18 joined to a peripheral wall 20 having an outer surface 27 and an inner surface 28 extending to an edge 22.
[0029] However, the second housing member 16 may be in the form of a plate and may contain a second front wall 24 having a peripheral edge 26. The housing members 14 and 16 may be hermetically sealed to each other by welding (For example, laser welding) overlapping edges 22 and 26 where they contact each other after incorporation of the anode 200 and the seal assembly 300 into the housing 12 if desired. Regardless of the particular configuration, the housing 12 may have a thickness "H2" of less than about 8 millimeters, for example from about 0.075 millimeter to about 30 millimeters, for example from about 0.1 millimeters to about 6 millimeters. for example from about 0.2 millimeters to about 5 millimeters. Further, the housing members 14 and / or 16 may be analogous to the metal substrate described with reference to the cathode in section III above such that an electrochemically active cathode material, for example a conductive polymer ( not shown), can be placed on the inside of its surface. Alternatively, a separate metal substrate may be adjacent to the housing member 14 and / or 16 and the conductive polymer coating may be applied thereto as a cathode. Nevertheless, prior to welding together the housing members 14 and 16, the anode wire seal assembly 300 is assembled around the anode wire 220 and the side wall 20 of the first housing member 14 to create a seal. at the anode port 34 as discussed in detail above with reference to section I. After assembly of the anode within the housing and sealing (e.g. As discussed above, the working electrolyte may optionally be introduced into the housing 12 through a fill port 120 as shown in FIG. 1, or by any other suitable means. Filling can be accomplished by placing the capacitor 10 in a vacuum chamber so that the fill port 120 extends into a reservoir of the working electrolyte.
[0030] When the chamber is evacuated, the pressure is reduced inside the capacitor 10. When the vacuum is released, the pressure inside the capacitor 10 is rebalanced, and the electrolyte is sucked through the capacitor 10. Filling port 120 in the capacitor 10. In addition to the components discussed above, although not illustrated, one or more separators may be used to help insulate the anode and the conductive polymer-coated cathode. one of the other. Examples of suitable materials for this purpose include, for example, porous polymeric materials (e.g., polypropylene, polyethylene, etc.), porous inorganic materials (e.g., fiberglass mats, porous glass, etc.), ion exchange resin materials, etc. Specific examples include ionic perfluorinated membranes of sulfonic acid polymers (e.g., NafionTM NafionTM from DuPont of Nemeours & Co., fluorocarbon polymer sulfonated membranes, polybenzimidazole (PBI) membranes, and polyether ether membranes). Although it prevents direct contact between the anode and the cathode, the separator 25 allows the flow of the ionic current from the electrolyte to the electrodes, irrespective of its particular configuration, the capacitor of the present invention. The invention can have excellent electrical properties, for example, the capacitor can have a high volumetric efficiency, for example from about 50,000 pF * V / cm3 to about 300,000 pF * V / cm3, in some embodiments. from about 60,000 pF * V / cm3 to about 200,000 pF * V / cm3, and in some embodiments from about 80,000 pF * V / cm3 to about 150,000 pF * V / cm3, determined at a fr quency of 120 Hz at room temperature (e.g., 25 ° C). The volumetric efficiency is determined by multiplying the forming voltage of a portion by dividing the product by, for example, a voltage of 175 volts for a 520 pF portion, which results in a capacitance thereof and then by volume of the part. training can be having a product capacitance of 91,000 pF * V. If the part occupies a volume of about 0.8 cm 3, this results in a volumetric efficiency of about 113,750 PF * V / cm 3. The capacitor may also have a high energy density which makes it suitable for use in high pulse applications. The energy density is generally determined according to the equation E = 1/2 * CV 2, where C is the capacitance in farads (F) and V is the working voltage of the capacitor in volts (V). Capacitance can, for example, be measured using a capacitance meter (for example, the Keithley 3330 Precision LCZ measuring instrument with Kelvin wires, 2 volt polarization and 1 volt signal) at operating frequencies of 10 volts. at 120 Hz (for example, 120 Hz) and at a temperature of 25 ° C. For example, the capacitor may have an energy density of about 2.0 joules per cubic centimeter (J / cm 3) or more, in some embodiments of about 3.0 J / cm 3, in some embodiments. from about 3.5 J / cm 3 to about 10.0 J / cm 3, and in some embodiments, from about 4.0 to about 8.0 J / cm 3. The capacitance can similarly be about 1 millifarad per square centimeter ("mF / cm 2") or more, in some embodiments of about 2 mF / cm 2 or more, in some embodiments of the invention. about 5 to about 50 mF / cm 2, and in some embodiments about 8 to about 20 mF / cm 2. The capacitor may also have a relatively high "breakdown voltage" (voltage at which the capacitor fails), for example about 180 volts or more, in embodiments of about 200 volts or more, and in some embodiments, from about 210 volts to about 10,260 volts. Equivalent series resistance ("ESR") - the degree to which the capacitor acts as a resistor when charging and discharging in an electrical circuit - may also be less than about 15,000 milliohms, in some embodiments less than about 10 000 milliohms, in some embodiments less than about 5,000 milliohms, and in some embodiments, from about 1 to about 4,500 milliohms, measured with a 2 volt bias and a 1 volt signal at a frequency of 120 Hz. In addition, the leakage current, which generally refers to the current flowing from a conductor to an adjacent conductor through an insulator, can be maintained at relatively low levels. For example, the numerical value of the normalized leakage current of a capacitor of the present invention is, in some embodiments, less than about 1 pA / pF * V, in some embodiments less than about 0.5. pA / pF * V, and in some embodiments less than about 0.1 pA / pF * V, where pA is microamperes and pF * V is the product of the capacitance and the nominal voltage. The leakage current can be measured using a leak test instrument (for example, MC 190 Test Leakage, Mantracourt Electronics LTD, UK) at a temperature of 25 ° C and at a certain rated voltage after a charging time of 25 ° C. about 60 to about 300 seconds. Such values of RSE and normalized leakage current can even be maintained after aging for a sensitive time at elevated temperatures. For example, these values may be maintained for about 100 hours or more, in some embodiments for about 300 hours to about 2500 hours, and in some embodiments, for about 400 hours to about 1500 hours (e.g. , 500 hours, 600 hours, 700 hours, 800 hours, 900 hours, 1,000 hours, 1,100 hours, or 1,200 hours) at temperatures in the range of about 100 ° C to about 250 ° C, and in certain embodiments from about 100 ° C to about 200 ° C (e.g., 100 ° C, 125 ° C, 150 ° C, 175 ° C, or 200 ° C) The electrolytic capacitor of the present invention can be used in a variety of applications, including but not limited to medical devices, such as implantable defibrillators, pacemakers, cardiovers, neural stimulators, drug delivery devices, and the like. ; automotive applications, military applications, such as RADAR systems; large-scale electronics, for example radios, televisions, etc. ; And so on. In one embodiment, for example, the capacitor may be used in an implantable medical device configured to provide high voltage therapeutic treatment (e.g., between approximately 500 volts and approximately 850 volts, or desirably between approximately 600 volts. volts and approximately 900 volts) to a patient. The device may contain a container or housing that is hermetically sealed and biologically inert. One or more wires are electrically coupled between the device and the patient's heart via a vein. Cardiac electrodes are provided to detect cardiac activity and / or provide tension to the heart. At least a portion of the wires (e.g., an end portion of the wires) may be provided adjacent or in contact with at least one of a ventricle and atrium of the heart. The device may also contain a capacitor bank that typically contains two or more capacitors connected in series and coupled to a battery that is internal or external to the device and provides power to the capacitor bank. In part because of the high conductivity, the capacitor of the present invention can achieve excellent electrical properties and thus be adapted for use in the capacitor bank of the implantable medical device. Regardless of its particular configuration, the capacitor of the present invention can exhibit excellent electrical properties. For example, the capacitor may have a high volumetric efficiency, for example from about 50,000 pF * V / cm3 to about 300,000 pF * V / cm3, in some embodiments from about 60,000 pF * V / cm3 to about 10,200,000 pF * V / cm3, and in some embodiments, from about 80,000 pF * V / cm3 to about 150,000 pF * V / cm3, determined at a frequency of 120 Hz and at room temperature (by for example, 25 ° C). The volumetric efficiency is determined by multiplying the forming voltage of a portion by its capacitance, and then dividing the product by the volume of the portion. For example, a forming voltage may be 175 volts for a portion having a capacitance of 520 pF, resulting in a product of 91,000 pF * V. If the part occupies a volume of about 0.8 cm 3, this results in a volumetric efficiency of about 113,750 PF * V / cm 3. The capacitor may also have a high energy density which makes it suitable for use in high pulse applications. The energy density is generally determined according to the equation E = 1/2 * CV2, where C is the capacitance in farads (F) and V is the working voltage of the capacitor in volts (V). Capacitance 30 may, for example, be measured using a capacitance meter (for example, the Keithley 3330 Precision LCZ 3028659 Gauge with Kelvin wires, 2 volt polarization and 1 volt signal) at operating frequencies of 30 volts. 10 to 120 Hz (for example, 120 Hz) and at a temperature of 25 ° C. For example, the capacitor may have an energy density of about 2.0 joules per cubic centimeter (J / cm 3) or more, in some embodiments of about 3.0 J / cm 3, in some embodiments of the invention. about 3.5 J / cm3 to about 15.0 J / cm3, and in some embodiments, from about 4.0 to about 12.0 J / cm3. The capacitance can similarly be about 1 millifarad per square centimeter ("mF / cm 2") or more, in some embodiments of about 2 mF / cm 2 or more, in some embodiments of the invention. from about 5 to about 50 mF / cm 2, and in some embodiments from about 8 to about 20 mF / cm 2. The capacitor may also have a relatively high "breakdown voltage" (voltage at which the capacitor becomes faulty), for example about 180 volts or more, in embodiments of about 200 volts or more, and in some embodiments, about 210 volts or more. volts at about 260 volts. Equivalent series resistance ("ESR") - the degree to which the capacitor acts as a resistor when charging and discharging in an electrical circuit - may also be less than about 15,000 milliohms, in some embodiments less than about 10 000 milliohms, in some embodiments less than about 5,000 milliohms, and in some embodiments, from about 1 to about 4,500 milliohms, measured with a 2 volt bias and a 1 volt signal at a In addition, the leakage current, which generally refers to the current flowing from a conductor to an adjacent conductor through an insulator, can be maintained at relatively low levels. For example, the numerical value of the normalized leakage current of a capacitor of the present invention is, in some embodiments, less than about 1 pA / pF * V, in some embodiments less than about 0.5 pA. In some embodiments, less than about 0.1 pA / pF * V, where pA is microamperes and pF * V is the product of the capacitance and the nominal voltage. The leakage current can be measured using a leak test instrument (for example, MC 190 Test Leakage, Mantracourt Electronics LTD, UK) at a temperature of 25 ° C and at a certain nominal voltage after a charging time of 25 ° C. about 60 to about 300 seconds. Such values of RSE and normalized leakage current can even be maintained after aging for a significant time at elevated temperatures. For example, these values may be maintained for about 100 hours or more, in some embodiments for about 300 hours to about 2500 hours, and in some embodiments, for about 400 hours to about 1500 hours (e.g. 500 hours, 600 hours, 700 hours, 800 hours, 900 hours, 1000 hours, 1100 hours, or 1200 hours) at temperatures in the range of about 100 ° C to about 250 ° C, and in some embodiments from about 100 ° C to about 200 ° C (eg, 100 ° C, 125 ° C, 150 ° C, 175 ° C, or 200 ° C) The electrolytic capacitor of the present invention can be used in a variety of applications, including but not limited to medical devices, such as implantable defibrillators, pacemakers, cardiovers, neural stimulators, drug delivery devices, and the like. ; automotive applications, military applications, e.g. RADAR systems; consumer electronics, such as radios, televisions, etc. ; And so on. In one embodiment, for example, the capacitor may be used in an implantable medical device configured to provide high voltage therapeutic treatment (e.g., between approximately 500 volts and approximately 850 volts, or desirably approximately 600 volts. volts and approximately 20 900 volts) to a patient. The device may contain a container or housing that is hermetically sealed and biologically inert. One or more wires are electrically coupled between the device and the patient's heart via a vein. Cardiac electrodes are provided to detect cardiac activity and / or to provide a voltage to the heart. At least a portion of the leads (e.g., an end portion of the leads) may be provided adjacent or in contact with at least one of a ventricle and an atrium of the heart. The device 30 may also contain a capacitor bank which typically contains two or more capacitors connected in series and coupled to a battery which is internal or external to the device and supplies power to the capacitor bank. In part because of the high conductivity, the capacitor of the present invention can achieve excellent electrical properties and thus be suitable for use in the capacitor bank of the implantable medical device. These and other modifications and variations of the present invention may be practiced by those skilled in the art without departing from the spirit and scope of the present invention. Moreover, it should be understood that aspects of the various embodiments may be modified in whole or in part. In addition, those skilled in the art will appreciate that the foregoing description is provided by way of example only, and is not intended to limit the invention further described in the appended claims.

权利要求:
Claims (24)
[0001]
REVENDICATIONS1. A wet electrolytic capacitor (10) for an implantable medical device comprising: a planar anode (200) which comprises a porous anode body coated with a dielectric layer, wherein the anode wire (220) extends from porous anode body; a working electrolyte which is in electrical contact with the planar anode (200); a housing (12) having an interior in which the planar anode (200) and the working electrolyte are positioned, the housing (12) having a wall defining an anode wire port (34); and a sealing assembly (300) which is connected to the housing (12) at the anode wire port (34), the sealing assembly (300) comprising: a metal housing (317) positioned within the anode wire port (34) and extending into the interior of the housing (12), wherein the metal housing (317) defines a cavity 20 through a portion of the wire anode (220) extends; an elastomeric ring (311) positioned within the cavity, wherein the elastomeric ring (311) contains an orifice through which a portion of the anode wire (220) extends; and a metal plate (301) positioned within the cavity, wherein the metal plate (301) contains an orifice through which a portion of the anode wire extends, wherein a bottom surface (319) metal plate (301) 3028659 75 is in contact with the elastomeric ring (311) within the cavity.
[0002]
The wet electrolytic capacitor (10) according to claim 1, wherein the sealing assembly (300) further comprises an insulating tube (306) which receives a portion of the anode wire (220), the insulating tube ( 306) having a first portion extending out of the housing (12) and a second portion extending through the anode wire port (34) into the interior of the housing (12).
[0003]
The wet electrolytic capacitor (10) of claim 2, wherein the insulating tube (306) comprises an insulating material.
[0004]
The wet electrolytic capacitor (10) according to claim 1, wherein the elastomeric ring (311) and the cavity of the metal housing (317) each have a conical portion, wherein the conical portion of the elastomeric ring (311) is located inside the cavity at the conical portion of the cavity.
[0005]
The wet electrolytic capacitor (10) of claim 1, wherein the metal housing (317) comprises titanium or an alloy thereof.
[0006]
The wet electrolytic capacitor (10) of claim 1, wherein the metal plate (301) comprises titanium or an alloy thereof.
[0007]
The wet electrolytic capacitor (10) of claim 1, wherein an electrochemically active cathode material is disposed on at least a portion of the housing (12). 3028659 76
[0008]
The wet electrolytic capacitor (10) of claim 7, wherein the electrochemically active cathode material comprises a conductive polymer. 5
[0009]
The wet electrolytic capacitor (10) of claim 8, wherein the conductive polymer is poly (3,4-ethylenedioxythiophene).
[0010]
The wet electrolytic capacitor (10) of claim 1, wherein the housing (12) comprises titanium or an alloy thereof.
[0011]
The wet electrolytic capacitor (10) according to claim 1, wherein the porous anode body comprises tantalum, niobium, or an electroconductive oxide thereof. 15
[0012]
The wet electrolytic capacitor (10) of claim 1, wherein the anode wire (220) comprises tantalum.
[0013]
The wet electrolytic capacitor (10) of claim 1, further comprising a separator 20 which surrounds at least a portion of the planar anode.
[0014]
The wet electrolytic capacitor (10) of claim 1, wherein the seal assembly (300) provides a hermetic seal at the anode wire port (34).
[0015]
An implantable defibrillator cardioverter comprising the wet electrolytic capacitor (10) of claim 1.
[0016]
16. A method of making a wet electrolytic capacitor (10) for use in an implantable medical device, the method comprising: positioning a planar, porous anode body having anode wire (220) ) extending therefrom into a housing (12) having a side wall into which an anode wire port (34) is formed such that a portion of the wire anode (220) extends through the anode wire port (34), wherein a seal assembly (300) surrounds the anode wire (220) at the wire lead port anode (34), the seal assembly (300) comprising a metal housing (317) positioned within the anode wire port (34) and extending into an interior of the housing ( 12), wherein the metal housing (317) defines a cavity through which a portion of the anode wire (220) extends; an elastomeric ring (311) positioned within the cavity, wherein the elastomeric ring (311) contains an orifice through which a portion of the anode wire (220) extends; and a metal plate (301) positioned within the cavity, wherein the metal plate (301) contains an orifice through which a portion of the anode wire (220) extends, wherein a bottom surface (319) of the metal plate (301) is in contact with the elastomeric ring (311) within the cavity; and forming a hermetic seal between the seal assembly and the anode wire (220).
[0017]
The method of claim 16, wherein the metal plate (301) and the elastomeric ring (311) are welded together to create a hermetic seal. 3028659 78
[0018]
The method of claim 16, further comprising welding the metal housing (317) to the housing (12).
[0019]
19. The method of claim 16, wherein the sealing assembly (300) further comprises an insulating tube (306) which receives a portion of the anode wire (220), the insulating tube (306) having a first portion extending out of the housing (12) and a second portion extending through the anode wire port (34) into the interior of the housing (12).
[0020]
The method of claim 19, wherein the insulating tube (306) comprises an insulating material.
[0021]
21. Process according to the metal housing alloy thereof.
[0022]
22. The method according to the metal plate (301) comprises titanium or an alloy thereof.
[0023]
23. The method of claim 16, wherein at least a portion of the housing (12) is coated with an electrochemically active cathode material.
[0024]
24. The method of claim 16, further comprising introducing a working electrolyte into the housing (12). claim 16, wherein (317) comprises titanium or claim 16, wherein

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同族专利:

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公开号 | 公开日

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US20160141110A1|2016-05-19|

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HK1218806A1|2017-03-10|

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FR3028659B1|2021-07-02|

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US9620293B2|2017-04-11|

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CN105609314A|2016-05-25|

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JP2016100602A|2016-05-30|

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DE102015221050A1|2016-05-19|

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法律状态:
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2021-10-25| PLFP| Fee payment|Year of fee payment: 7 |

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2022-03-04| CD| Change of name or company name|Owner name: KYOCERA AVX COMPONENTS CORPORATION, US Effective date: 20220125 |

优先权:

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申请号 | 申请日 | 专利标题

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US14/542,761|US9620293B2|2014-11-17|2014-11-17|Hermetically sealed capacitor for an implantable medical device|

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