HK1185714B - Solid electrolytic capacitor with enhanced mechanical stability under extreme conditions - Google Patents

Description

Solid electrolytic capacitor with improved mechanical stability for use in extreme environments

RELATED APPLICATIONS

Priority of U.S. provisional application 61/622,651 filed on day 11, 2012 and U.S. provisional application 61/659,529 filed on day 14, 6, 2012, the entire disclosures of which are incorporated herein by reference.

Background

Electrolytic capacitors, such as tantalum capacitors, are increasingly used in circuit design due to their volumetric efficiency, reliability and process compatibility. For example, one type of capacitor that has been developed is a solid electrolytic capacitor that includes an anode (e.g., tantalum), a dielectric oxide film (e.g., tantalum pentoxide, Ta) formed on the anode₂O₅) A solid electrolyte layer, and a cathode. The solid electrolyte layer may be formed from a conductive polymer, as described in U.S. Pat. Nos. 5,457,862, 5,473,503 and 5,729,428 to Sakata et al and U.S. Pat. No. 5,812,367 to Kudoh et al. Unfortunately, however, such solid electrolytes have poor high temperature stability due to their tendency to transition from a doped state to an undoped state or from an undoped state to a doped state at high temperatures. To address these and other problems, hermetically sealed capacitors have been developed to limit oxygen contact with the conductive polymer during use. For example, U.S. patent publication US2009/0244812 to Rawal et al describes a capacitor assembly comprising a conductive polymer capacitor hermetically sealed within a ceramic housing containing an inert gas. As stated by Rawal et al, the ceramic housing limits the amount of oxygen and moisture supplied to the conductive polymer, thereby reducing the likelihood of oxidation in high temperature environments and thereby improving the thermal stability of the capacitor assembly. However, despite the benefits achieved, problems still remain. For example, capacitors sometimes have poor mechanical stability under extreme conditions (e.g., high temperatures in excess of about 175 ℃ and/or high voltages in excess of about 35 volts), resulting in the capacitor element peeling away from the circuit board and poor electrical performance.

Accordingly, there is a need for a solid electrolytic capacitor assembly having improved performance under extreme conditions.

Disclosure of Invention

According to one embodiment of the present invention, a capacitor assembly is disclosed that includes a capacitor element including an anode formed of an anodized sintered porous anode body and a layer of solid electrolyte coated on the anode. The assembly further includes a housing defining an interior cavity, the electrical component being disposed within the interior cavity and hermetically sealed. The housing includes a surface having a dimension in a longitudinal direction and a dimension in a transverse direction, the surface further defining an outer edge. An anode terminal electrically connected to the anode body, the anode terminal including an external anode termination adjacent to a surface of the housing. A cathode terminal electrically connected to the solid electrolyte, the cathode terminal comprising an external cathode termination portion adjacent to a surface of the housing. The external anode terminal portion, the external cathode terminal portion, or both extend outwardly in a transverse direction a distance beyond an outer edge of the housing surface.

In accordance with another embodiment of the present invention, a capacitor assembly is disclosed that includes a capacitor element including an anode formed of an anodized sintered porous anode body and a layer of solid electrolyte coated on the anode. The assembly further includes a housing defining an interior cavity, the capacitor element being disposed within the interior cavity and hermetically sealed in the presence of an atmosphere comprising an inert gas. The housing includes a lower surface having a dimension in a longitudinal direction and a dimension in a transverse direction, the lower surface further defining an outer edge. An anode terminal electrically connected to the anode body, the anode terminal including an external anode terminal portion adjacent to the lower surface of the case and disposed on a plane parallel to the lower surface of the case. The external anode terminal portion extends outward in a lateral direction beyond an outer edge of the case surface by a first distance. A cathode terminal electrically connected to the solid electrolyte, the cathode terminal comprising an external cathode terminal portion adjacent to and disposed on a plane parallel to the lower surface of the housing. The external cathode terminal portion extends outwardly in a lateral direction a second distance beyond an outer edge of the housing surface.

In accordance with another embodiment of the present invention, a capacitor assembly is disclosed that includes a capacitor element including an anode formed of an anodized sintered porous anode body and a layer of solid electrolyte coated on the anode. The assembly further includes a housing defining an interior cavity, the electrical component being disposed within the interior cavity and hermetically sealed. The housing includes a surface having a dimension in a longitudinal direction and a dimension in a transverse direction, the surface further defining an outer edge. An anode terminal electrically connected to the anode body, the anode terminal including an external anode terminal portion adjacent to the surface of the housing. A cathode terminal electrically connected to the solid electrolyte, the cathode terminal including an external cathode terminal portion adjacent to the surface of the housing. At least one side of the external anode terminal portion, the external cathode terminal portion, or both extends outwardly in a lateral direction a distance beyond an outer edge of the housing surface. A side surface of the external anode terminal portion, a side surface of the external cathode terminal portion, or both of them is folded at an outer edge so that the side surface is adjacent to a wall surface of the case and is perpendicular to the case surface.

Other aspects and features of the present invention will be described in more detail below.

Drawings

A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth more particularly in the detailed description, which makes reference to the appended figures and numerals, in which:

FIG. 1 is a side cross-sectional view of one embodiment of a capacitor assembly of the present invention;

FIG. 2 is a bottom view of the capacitor assembly shown in FIG. 1;

FIG. 3 is a side cross-sectional view of another embodiment of a capacitor assembly of the present invention;

FIG. 4 is a top view of yet another embodiment of a capacitor assembly of the present invention;

FIG. 5 is a bottom view of another embodiment of the capacitor assembly of the present invention;

FIG. 6 is a bottom view of yet another embodiment of the capacitor assembly of the present invention;

FIG. 7(a) is a side cross-sectional view of another embodiment of a capacitor assembly of the present invention;

FIG. 7(b) is a side cross-sectional view of yet another embodiment of a capacitor assembly of the present invention;

FIG. 8(a) is a bottom view of the capacitor assembly shown in FIG. 7 (a);

FIG. 8(b) is a bottom view of the capacitor assembly shown in FIG. 7 (b);

FIG. 9(a) is a bottom view of another embodiment of the capacitor assembly of the present invention; and

fig. 9(b) is a bottom view of yet another embodiment of the capacitor assembly of the present invention.

In the drawings, like reference characters designate like or similar parts of the invention.

Detailed Description

It is to be understood that the following is merely a description of exemplary embodiments of the present invention and is not intended as a limitation on the broader aspects of the present invention, which broader aspects of the present invention are embodied in the exemplary constructions.

In general, the present invention relates to a capacitor assembly having thermal and mechanical stability under extreme conditions. Thermal stability is achieved by enclosing and sealing the capacitor element within a housing in the presence of an atmosphere containing an inert gas, thereby limiting the amount of oxygen and moisture supplied to the capacitor solid electrolyte. In order to provide good mechanical stability, the capacitor assembly further comprises at least one external terminal portion (e.g. an anode and/or cathode terminal) extending beyond the outer edge of the outer shell surface. In the present invention, the extent to which the external terminal portions extend beyond the outer edge of the surface of the housing is selectively controlled with respect to the size of the housing to increase the degree of availability of the surface area for soldering to the circuit board. It is believed that this helps the capacitor assembly better withstand the vibrational forces experienced during use without falling off the circuit board. In this way, the capacitor assembly is able to work better in extreme conditions. A particular advantage of the present invention is that the assembly reduces the likelihood of separation without substantially increasing the surface area occupied by the circuit board. This is because the improved mechanical stability is accomplished by selectively controlling the size of the external terminal portions, rather than increasing the size of the housing and/or the capacitor element.

Various embodiments of the invention will be described in more detail below.

I. Capacitor element

A. Anode

When the capacitor assembly is used in high voltage applications, it is generally desirable that the anode of the capacitor element be formed from a powder having a relatively low specific charge, for example, less than about 70,000 microfarad volts per gram ("μ F V/g"), in some embodiments from about 2,000 μ F V/g to about 65,000 μ F V/g, and in some embodiments, from about 5,000 to about 50,000 μ F V/g. Of course, while it is sometimes desirable to use a powder that is less than electrically charged, this is not meant to require that such be used. That is, the powder may also have a relatively high specific charge of about 70,000 microfarad volts per gram ("μ F V/g") or more, in some embodiments about 80,000 μ F V/g or more, in some embodiments about 90,000 μ F V/g or more, in some embodiments about 100,000 μ F V/g or more, and in some embodiments, from about 120,000 to about 250,000 μ F V/g.

The powder comprises a valve metal (i.e. a metal capable of oxidation) or a compound based on a valve metal, such as tantalum, niobium, aluminium, hafnium, titanium and their respective alloys, oxides, nitrides or the like. For example, the valve metal composition may comprise a conductive oxide of niobium, such as an oxide of niobium having a niobium to oxygen atomic ratio of 1:1.0 ± 1.0, in some embodiments a niobium to oxygen atomic ratio of 1:1.0 ± 0.3, in some embodiments a niobium to oxygen atomic ratio of 1:1.0 ± 0.1, and in some embodiments a niobium to oxygen atomic ratio of 1:1.0 ± 0.05. For example, the oxide of niobium may be NbO_0.7、NbO_1.0、NbO_1.1And NbO₂. Examples of such valve metal oxides are described in Fife, U.S. Pat. No. 6,322,912, Fife et al, U.S. Pat. No. 6,391,275, Fife et al, U.S. Pat. No. 6,416,730, Fife, U.S. Pat. No. 6,527,937, Kimmel et al, U.S. Pat. No. 6,576,099, Fife et al, U.S. Pat. No. 6,592,740, Kimmel et al, U.S. Pat. No. 6,639,787, Kimmel et al, U.S. Pat. No. 7,220,397, Schnitter et al, U.S. patent application 2005/0019581, Schnitter et al, U.S. patent application 2005/0103638, and Thomas et al, U.S. patent application 2005/0013765.

The particles of the powder may be, for example, in the form of flakes, horns, nodules, and mixtures or variations thereof. The particles generally have a sieve size distribution of at least about 60 mesh, in some embodiments from about 60 mesh to about 325 mesh, and in some embodiments, from about 100 mesh to about 200 mesh. Further, the specific surface area is from about 0.1 to about 10.0m²(iv) g, in some embodiments, from about 0.5 to about 5.0m²In some implementations,/gIn examples, from about 1.0 to about 2.0m²(ii) in terms of/g. The term "specific surface area" means a surface area measured by physical gas adsorption (B.E.T.) published by Brunauer, Emmet and Teller, Inc., 60/309 of American Chemical Society, USA, and the adsorbed gas is nitrogen. Also, the bulk (or Scott) density is generally from about 0.1 to about 5.0g/cm³And in some embodiments, from about 0.2 to about 4.0g/cm³And in some embodiments, from about 0.5 to about 3.0g/cm³。

Other components may also be added to the powder to promote the formation of the anode body. For example, a binder (binder) and/or a lubricant may be used to ensure that the particles properly bind to each other when pressed into an anode body. Suitable binders include camphor, stearic acid and other soap fatty acids, polyethylene glycol (Carbowax) (allied carbide), glyphosate (glyphosate) (general electric), polyvinyl alcohol, naphthalene, vegetable waxes and microcrystalline waxes (refined paraffin waxes). The binder may be dissolved or dispersed in a solvent. Typical examples of the solvent include water, alcohol and the like. When used, the binder and/or lubricant may be present in an amount of about 0.1 to about 8 weight percent of the total weight. However, it should be understood that the present invention does not necessarily require the use of binders and lubricants.

The resulting powder may be compacted using any conventional powder press. For example, the die may be a single station press employing a single die and one or more punches. Alternatively, an anvil die using only a single die and a single lower punch may also be employed. There are several basic types of single station presses, such as cam presses, toggle presses/toggle presses and eccentric presses/crank presses with different production capacities, which may be, for example, single-action, double-action, floating-bed presses, movable-bed presses, opposed-ram presses, screw presses, impact presses, hot-pressing presses, impression presses or finishing presses. After pressing, the resulting anode body may be cut into any desired shape, such as square, rectangular, circular, oval, triangular, hexagonal, octagonal, heptagonal, pentagonal, and the like. The anode body may also have a "slot" shape that includes one or more grooves, flutes, depressions or depressions therein to increase the surface area to volume ratio, minimize ESR and extend the frequency response of the capacitor. The anode body will then undergo a heating step to remove most, if not all, of the binder/lubricant. For example, the anode body is typically heated using an oven at a temperature of about 150 ℃ to 500 ℃. Alternatively, the particles may be contacted with an aqueous solution to remove the binder/lubricant, as described in US6,197,252 to Bishop et al.

Once formed, the anode body is sintered. The sintering temperature, atmosphere and time depend on various factors such as anode type, anode size, etc. In general, sintering is carried out at a temperature of from about 800 ℃ to about 1900 ℃, in some embodiments, from about 1000 ℃ to about 1500 ℃, in some embodiments, from about 1100 ℃ to about 1400 ℃, and for a time of from about 5 minutes to about 100 minutes, in some embodiments, from about 30 minutes to about 60 minutes. If desired, sintering may be carried out in an atmosphere that limits the transfer of oxygen atoms to the anode. For example, sintering may be performed in a reducing atmosphere, such as in vacuum, inert gas, hydrogen, and the like. The pressure of the reducing atmosphere is from 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 (e.g., argon or nitrogen) may also be used.

An anode lead may also be connected to the anode body and extend longitudinally therefrom. The anode lead may be in the form of a wire, sheet, etc., and may be formed using a valve metal compound such as tantalum, niobium oxide, etc. The attachment of the lead may be accomplished using known techniques, such as welding the lead to the anode body or embedding the lead into the anode body during anode body formation (e.g., prior to pressing and/or sintering).

The anode is also coated with a dielectric layer. The medium can be such thatForming: the sintered anode is anodized ("anodizing") to form a dielectric layer on and/or within the anode. For example, a tantalum (Ta) anode may be anodized to tantalum pentoxide (Ta)₂O₅). Generally, anodization is performed by first applying a solution to the anode, such as by dipping the anode into an electrolyte. A solvent, such as water (e.g., deionized water), is typically employed. In order to enhance the ion conductivity, a compound that can be dissociated in a solvent to form ions may be used. Examples of such compounds include, for example, acids, as described in the electrolyte section below. For example, the acid (e.g., phosphoric acid) may be present in the anodizing solution in an amount of from about 0.01wt% to about 5wt%, in some embodiments, from about 0.05wt% to about 0.8wt%, and in some embodiments, from about 0.1wt% to about 0.5 wt%. Mixtures of acids may also be employed if desired.

A current is passed through the anodizing solution to form a dielectric layer. The formation voltage value determines the thickness of the dielectric layer. For example, the power supply is initially established in a constant current mode until the desired voltage is reached. The power supply can then be switched to a constant potential mode to ensure that the desired dielectric layer thickness is formed over the entire surface of the anode. Of course, other methods known to those skilled in the art, such as a pulse constant potential method or a step constant potential method, may be used. The voltage at which anodization occurs typically ranges from about 4 to about 250V, in some embodiments, from about 9 to about 200V, and in some embodiments, from about 20 to about 150V. During anodization, the anodization solution is maintained at an elevated temperature, for example, about 30 ℃ or higher, in some embodiments, from about 40 ℃ to about 200 ℃, and in some embodiments, from about 50 ℃ to about 100 ℃. The anodization may also be carried out at room temperature or lower. The resulting dielectric layer may be formed on the surface of the anode and within the anode hole.

B. Solid electrolyte

The capacitor element further comprises a solid electrolyte as the cathode of the capacitor. For example, manganese dioxide solid electrodesThe electrolyte can be manganese nitrate (Mn (NO)₃)₂) And (4) pyrolysis is carried out. Such a technique is described, for example, in U.S. patent US4,945,452 to Sturmer et al. The solid electrolyte may also comprise one or more conductive polymer layers. The conductive polymer in these layers is typically pi-conjugated and is conductive after oxidation or reduction, e.g., has a conductivity of at least about 1 μ S-cm after oxidation^-1. Examples of such pi-conjugated conductive polymers include, for example, polyheterocycles (e.g., polypyrrole; polythiophene, polyaniline, and the like), polyacetylene, poly-p-phenylene, polyphenolates, and the like. Particularly suitable electrically conductive polymers are substituted polythiophenes having the following general structure:

wherein the content of the first and second substances,

t is O or S;

d is optionally substituted C₁-C₅Alkenyl groups (e.g., methylene, vinyl, n-propenyl, n-butenyl, n-pentenyl, etc.);

R₇is linear or branched and optionally C₁-C₁₈Alkyl substituents (e.g., methyl, ethyl, n-or isopropyl, n-butyl, isobutyl, sec-or tert-butyl, n-pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 1-ethylpropyl, 1-dimethylpropyl, 1, 2-dimethylpropyl, 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.); optionally C₅-C₁₂Cycloalkyl substituents (e.g., cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, etc.); optionally C₆-C₁₄Aryl substituents (e.g., phenyl, naphthyl, and the like); optionally C₇-C₁₈Aralkyl substituents (e.g., benzyl, o-, m-, p-tolyl, 2,3-, 2,4-, 2,5-, 2,6, 3,4-, 3, 5-xylyl, trimethylphenyl, etc.); optionally C₁-C₄A hydroxyalkyl substituent or a hydroxy substituent; and

q is an integer from 0 to 8, in some embodiments from 0 to 2, and in some embodiments, 0; and

n is 2 to 5,000, in some embodiments 4 to 2,000, and in some embodiments 5 to 1,000. "D" or "R₇Examples of substituents of "include, for example, alkyl, cycloalkyl, aryl, aralkyl, alkoxy, halo, ether, thioether, disulfide, sulfoxide, sulfone, sulfonate, amino, aldehyde, ketone, carboxylate, carboxylic acid, carbonate, carboxylate, cyano, alkylsilane, and alkoxysilyl, carboxamide groups and the like.

Particularly suitable thiophene polymers are those in which "D" is optionally substituted C₂-C₃An olefin substituted thiophene polymer. For example, the polymer can be an optionally substituted poly (3, 4-ethylenedioxythiophene) having the general structure:

methods of forming conductive polymers such as those described above are well known in the art. For example, U.S. patent application 6,987,663 to Merker et al describes various techniques for forming substituted thiophenes from precursor monomers. For example, the precursor monomer has the following structure:

wherein the content of the first and second substances,

T、D、R₇and q is as defined above. Particularly suitable thiophene monomers are those in which "D" is optionally substituted C₂-C₃An alkenyl thiophene monomer. For example, optionally substituted 3, 4-alkenes having the general structureHydrocarbyl dioxythiophene:

wherein R is₇And q is as defined above. In a particular embodiment, "q" is 0. An example of a commercially suitable 3, 4-vinyldioxythiophene is Heraeus Clevios as Clevios^TMM name product sold. Other suitable monomers are also described in U.S. patent application 5,111,327 to Blohm et al and U.S. patent application 6,635,729 to Groenendaal et al. Derivatives of these monomers, such as dimers or trimers of the above monomers, may also be employed. Higher molecular weight derivatives, such as tetramers, pentamers, etc. of the monomers are also suitable for use in the present invention. The derivatives may consist of identical or different monomer units, and may be used both in pure form and in the form of a mixture with another derivative and/or monomer. Oxidized or reduced forms of these precursor monomers may also be used.

In the presence of an oxidation catalyst, thiophene monomers undergo chemical polymerization. The oxidation catalyst typically comprises a transition metal cation, such as an iron (III), copper (II), chromium (VI), cerium (IV), manganese (VII), ruthenium (III) cation, and the like. Dopants may also be used to provide excess charge to the conducting polymer and to stabilize the conductivity of the polymer. The dopant generally comprises an inorganic or organic anion, such as a sulfonate ion. In certain embodiments, the oxidation catalyst used in the precursor solution includes a cation (e.g., a transition metal) and an anion (e.g., a sulfonic acid) to provide both catalytic and doping functions. For example, the oxidation catalyst can be a transition metal salt, including an iron (III) cation, such as an iron (III) halide (e.g., FeCl)₃) Or iron (III) salts of other mineral acids, e.g. Fe (ClO)₄)₃Or Fe₂(SO₄)₃And Iron (III) salts of organic acids and iron (III) salts of inorganic acids containing organic radicals. Examples of iron (III) salts of inorganic acids having organic groups include, for example, C₁-C₂₀Iron (III) salts of sulfuric monoesters of alkanols (e.g., iron (III) lauryl sulfate). Also, examples of the iron (III) salt of an organic acid include, for example, C₁-C₂₀Iron (iii) alkylsulfonate (e.g., methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, butanesulfonic acid, or dodecylsulfonic acid); an iron (iii) salt of an aliphatic perfluorosulfonic acid (such as trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, or perfluorooctanesulfonic acid); aliphatic C₁-C₂₀Iron (III) carboxylates (e.g., 2-ethylhexylcarboxylic acid); an iron (iii) salt of an aliphatic perfluorocarboxylic acid (such as trifluoroacetic acid or perfluorooctanoic acid); optionally is covered with C₁-C₂₀An iron (iii) salt of an alkyl-substituted aromatic sulfonic acid (e.g., benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid, or dodecylbenzenesulfonic acid); and iron (iii) cycloalkanesulfonate salts (e.g., camphorsulfonic acid), and the like. Mixtures of the above-mentioned iron (III) salts can also be used. Iron (III) p-toluenesulfonate and iron (III) o-toluenesulfonate, and mixtures thereof, are particularly suitable for the present invention. One commercially suitable iron (III) o-toluenesulfonate salt is h.c. starck GmbH under the name Clevios^TMC, the product sold.

The conductive polymer coating layer may be formed using various methods. In one embodiment, the oxidation catalyst and monomer may be applied sequentially or together, such that the polymerization reaction occurs in situ on the part. Suitable coating techniques for forming the conductive polymer coating include screen printing, dipping, electrophoretic coating, spraying, and the like. For example, the monomer may be initially mixed with an oxidation catalyst to form a precursor solution. Once the mixture is formed, it can be coated onto a metal substrate and then allowed to polymerize, thereby forming a conductive coating on the surface. Alternatively, the oxidation catalyst and monomer may be coated sequentially. For example, in one embodiment, the oxidation catalyst may be dissolved in an organic solvent (e.g., butanol) and then applied as an impregnation solution. The part is then dried to remove the solvent from the part. The part is then dipped into a solution containing the monomer.

Depending on the oxidizing agent used and the desired reaction time, the polymerization is conducted at a temperature of from about-10 ℃ to about 250 ℃, and in some embodiments, from about 0 ℃ to about 200 ℃. Suitable polymerization processes, such as those described above, are described in more detail in U.S. Pat. No. 4,7,515,396 to Biler. Other methods of applying such conductive coatings are described in U.S. patent application 5,457,862 to Sakata et al, U.S. patent application 5,473,503 to Sakata et al, U.S. patent application 5,729,428 to Sakata et al, and U.S. patent application 5,812,367 to Kudoh et al.

In addition to in situ coating, the conductive polymer coating may also be applied in the form of a dispersion of conductive polymer particles. Although the particle size may vary, it is generally desirable that the particle size be smaller to increase the surface area available for adhesion to the anode part. For example, the average particle size of the particles is from 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. D of the particles₉₀Value (particle size less than or equal to D)₉₀Particles having a value of 90% of the total volume of all solid particles) is about 15 microns or less, in some embodiments about 10 microns or less, and in some embodiments, from about 1 nanometer to about 8 microns. The diameter of the particles can be determined by well-known methods, such as ultracentrifugation, laser diffraction, and the like.

The use of a separate counterion to neutralize the positive charge carried by the substituted polythiophene can enhance the formation of the conductive polymer into particles. In some cases, the polymer may have positive and negative charges in the structural unit, the positive charge being located on the backbone and the negative charge optionally being located on an "R" substituent, such as a sulfonate or carboxylate group. The anionic groups, which may be present on the radical "R", may saturate some or all of the positive charge on the backbone. In general, polythiophenes may be cationic, neutral or even anionic. However, because the polythiophene backbone is positively charged, they are all considered cationic polythiophenes.

The counterion may be monomeric anionic or polymericA polyanion. The polymeric anion can be, for example, a polycarboxylic anion (e.g., polyacrylic acid, polymethacrylic acid, polymaleic acid, etc.); polysulfonate anions (e.g., polystyrene sulfonic acid ("PSS"), polyvinylsulfonic acid, etc.), and the like. The acid may also be a copolymer, such as copolymers of vinyl carboxylic and vinyl sulfonic acids with other polymerizable monomers, such as acrylates and styrene. Likewise, suitable monomeric anions include, for example, C₁-C₂₀Alkyl sulfonic acid (e.g., dodecyl sulfonic acid) anions; aliphatic perfluorosulfonic acid (such as trifluoromethanesulfonic acid, perfluorobutanesulfonic acid, or perfluorooctanesulfonic acid) anion; aliphatic C₁-C₂₀Carboxylic acid (2-ethylhexyl carboxylic acid) anion; aliphatic perfluorocarboxylic acid (such as trifluoroacetic acid or perfluorooctanoic acid) anions; optionally is covered with C₁-C₂₀Alkyl-substituted aromatic sulfonic acid (e.g., benzenesulfonic acid, o-toluenesulfonic acid, p-toluenesulfonic acid, or dodecylbenzenesulfonic acid) anion; cycloalkanesulfonic acid (e.g., camphorsulfonic acid or tetrafluoroborate, hexafluorophosphate, perchlorate, hexafluoroantimonate, hexafluoroarsenate or hexachloroantimonate) anions, and the like. Particularly suitable counter anions (counterions) are polymeric anions such as polycarboxylic acids or polysulfonic acids such as polystyrene sulfonic acid ("PSS"). The molecular weight of such polymeric anions is generally from about 1,000 to about 2,000,000, and in some embodiments, from about 2,000 to about 500,000.

When employed, the weight ratio of such counterions to substituted polythiophenes in a given coating is generally from about 0.5:1 to about 50:1, in some embodiments from about 1:1 to about 30:1, and in some embodiments, from about 2:1 to about 20: 1. The weight of the substituted polythiophene mentioned in the above reference weight ratio refers to the weight of the monomer fraction used, assuming complete conversion of the monomer during polymerization.

The dispersion may also include one or more binders to further enhance the adhesion of the polymeric layer and also to improve the stability of the particles within the dispersion. The binder may be organic, such as polyvinyl alcohol, polyvinyl pyrrolidone, polyvinyl chloride, polyvinyl acetate, polyvinyl butyrate, polyacrylates, polyacrylamides, polymethacrylates, polymethacrylamides, polyacrylonitrile, styrene/acrylates, vinyl acetate/acrylates and ethylene/vinyl acetate copolymers, polybutadiene, polyisoprene, polystyrene, polyethers, polyesters, polycarbonates, polyurethanes, polyamides, polyimides, polysulfones, melamine-formaldehyde resins, epoxy resins, silicone resins or cellulose. Crosslinkers may also be employed to enhance the adhesive ability of the binder. Such crosslinking agents include, for example, melamine compounds, blocked isocyanates or functional silanes, such as 3-glycidoxypropyltrialkylsilane, tetraethoxysilane and tetraethoxysilane hydrolysates or crosslinkable polymers, such as polyurethanes, polyacrylates or polyolefins, and subsequent crosslinking. Other components, such as dispersing agents (e.g., water), surface active substances, etc., may also be included in the dispersion, as is well known in the art.

If desired, one or more of the coating steps described above may be repeated until the desired coating thickness is achieved. In some embodiments, only a relatively thin coating can be formed at a time. The total target thickness of the coating is generally dependent on the desired performance of the capacitor. Generally, the resulting conductive polymer coating has a thickness of from about 0.2 micrometers ("μm") to about 50 μm, in some embodiments, from about 0.5 μm to about 20 μm, and in some embodiments, from about 1 μm to about 5 μm. It should be understood that the coating thickness need not be the same at all locations on the part. However, the average thickness of the coating on the substrate generally falls within the ranges described above.

The conductive polymer layer may optionally be healed (heal). Healing may be performed after each application of the conductive polymer layer or after the entire conductive polymer coating is applied. In some embodiments, the conductive polymer may be healed by immersing the component in an electrolyte, and then applying a constant voltage to the solution until the current is reduced to a preselected level. This healing can be accomplished in multiple steps, if desired. For example, the electrolyte may be a dilute solution of the monomer, catalyst and dopant in an alcohol solvent (e.g., ethanol). The coating may also be cleaned, if desired, to remove various byproducts, excess reagents, etc.

C. Other Components

The capacitor element may also contain other layers as is well known in the art, if desired. For example, a protective coating layer, such as one formed of a relatively insulating resin material (natural resin or synthetic resin), may optionally be applied between the dielectric layer and the solid electrolyte. Certain resinous materials useful in the present invention include, but are not limited to, polyurethanes, polystyrenes, unsaturated or saturated fatty acid esters (e.g., glycerol esters), and the like. For example, suitable fatty acid esters include, but are not limited to, laurate, myristate, palmitate, stearate, eleostearate, oleate, linoleate, linolenate, lacunate, and the like. These fatty acid esters have been found to be particularly useful when used in relatively complex combinations to form "drying oils" (drying oils) which enable the resulting films to rapidly polymerize to form stable layers. Such drying oils may include mono-, di-and/or triglycerides having a glycerol backbone of one, two and three esterified fatty acyl groups, respectively. For example, some suitable drying oils that may be used include, but are not limited to, olive oil, linseed oil, castor oil, tung oil, soybean oil, and shellac. These and other protective coating materials are described in more detail in U.S. patent US6,674,635 to Fife et al.

The component may also be coated with a carbon layer (e.g., graphite) and a silver layer, respectively, if desired. For example, a silver layer may serve as a solderable conductor, contact layer and/or charge collector for a capacitor, and a carbon layer may limit the silver layer from contacting the solid electrolyte. Such coatings may cover part or the entire solid electrolyte.

Generally, the capacitor element of the present invention is substantially free of a resin (e.g., epoxy resin) encapsulating the capacitor element, which is generally employed in conventional solid electrolytic capacitors. In addition, the packaging of the capacitor element can render it unstable under extreme environmental conditions, such as high temperature (e.g., greater than about 175 ℃) and/or high voltage (e.g., greater than about 35 volts).

II. outer cover

As described above, the capacitor element is sealed in a case. The sealing is typically performed in an atmosphere comprising at least one inert gas to inhibit oxidation of the solid electrolyte during use. The inert gas includes, for example, nitrogen, helium, argon, xenon, neon, krypton, radon, etc., and a mixture thereof may also be used. Generally, the inert gas comprises a majority of the composition of the atmosphere within the enclosure, such as from about 50wt% to about 100wt%, in some embodiments from about 75wt% to about 100wt%, and in some embodiments, from about 90wt% to about 99wt% of the atmosphere. Relatively small amounts of non-inert gases such as carbon dioxide, oxygen, water vapor, etc. may also be employed if desired. In this case, however, the non-inert gas typically comprises 15wt% or less, in some embodiments about 10wt% or less, in some embodiments about 5wt% or less, in some embodiments about 1wt% or less, and in some embodiments, from about 0.01wt% to about 1wt% of the housing atmosphere. For example, the moisture content (expressed as relative humidity) is about 10% or less, in some embodiments about 5% or less, in some embodiments about 1% or less, and in some embodiments, about 0.01-5%.

The housing may be made of a variety of different materials, such as metal, plastic, ceramic, and the like. For example, in one embodiment, the housing includes one or more layers of a metal, such as tantalum, niobium, aluminum, nickel, hafnium, titanium, copper, silver, steel (e.g., stainless steel), alloys thereof (e.g., conductive oxides), composites thereof (e.g., metal coated with conductive oxides), and the like. In another embodiment, the housing may include one or more layers of ceramic materials, such as aluminum nitride, aluminum oxide, silicon oxide, magnesium oxide, calcium oxide, glass, and the like, and combinations thereof.

The housing may be any desired shape, such as cylindrical, D-shaped, rectangular, triangular, prismatic, etc. Referring to fig. 1-2, for example, an embodiment of a capacitor assembly 100 is shown that includes a housing 122 and a capacitor element 120. In this particular embodiment, the housing 122 is substantially rectangular. Generally, the housing and the capacitor element have the same or similar shape so that the capacitor element is easily placed into the interior cavity. For example, in the illustrated embodiment, capacitor element 120 and housing 122 are substantially rectangular.

The capacitor assembly of the present invention can have relatively high volumetric efficiency, if desired. To increase this efficiency, the capacitor element typically occupies a large portion of the internal cavity of the housing. For example, the capacitor element may comprise about 30vol% or more, in some embodiments about 50vol% or more, in some embodiments about 60vol% or more, in some embodiments about 70vol% or more, in some embodiments from about 80vol% to about 98vol%, in some embodiments, from about 85vol% to about 97vol% of the interior cavity of the housing. For this reason, the difference in size between the capacitor element and the internal cavity defined by the housing is typically relatively small.

For example, fig. 1 shows that the length of capacitor element 120 (excluding the length of anode lead 6) is similar to the length of internal cavity 126 defined by casing 122. For example, the ratio of the anode length (-y-direction) to the internal cavity length is from about 0.40 to 1.00, in some embodiments from about 0.50 to about 0.99, in some embodiments from about 0.60 to about 0.99, and in some embodiments, from about 0.70 to about 0.98. The length of capacitor element 120 is about 5mm to about 10 mm and the length of internal cavity 126 is about 6 mm to about 15 mm. Also, the ratio of the height of the capacitor element 120 (-z direction) to the height of the internal cavity 126 is about 0.40-1.00, in some embodiments about 0.50-0.99, in some embodiments about 0.60-0.99, and in some embodiments, about 0.70-0.98. The ratio of the width of capacitor element 120 (in the (-x direction) to the width of internal cavity 126 is about 0.50-1.00, in some embodiments about 0.60-0.99, in some embodiments about 0.70-0.99, in some embodiments about 0.80-0.98, and in some embodiments about 0.85-0.95. For example, the width of capacitor element 120 is from about 2 millimeters to about 10 millimeters, the width of internal cavity 126 is from about 3 millimeters to about 10 millimeters, the width of capacitor element 120 is from about 0.5 millimeters to about 2 millimeters, and the height of internal cavity 126 is from about 0.7 to about 6 millimeters.

Optionally, a polymeric standoff may be in contact with one or more surfaces of the capacitor element, such as the back surface, the front surface, the top surface, the bottom surface, the side surfaces, or any combination thereof. Such polymer fixtures may reduce the likelihood of the capacitor element peeling from the housing. In this regard, the polymer fixture may have some degree of strength to hold the capacitor elements in a relatively fixed position even when the capacitor is subjected to vibrational forces, but not so strong as to cause cracking thereof. For example, the polymer fixture has a tensile strength of about 1 to about 150 megapascals ("MPa"), in some embodiments about 2 to about 100MPa, in some embodiments about 10 to about 80MPa, and in some embodiments about 20 to about 70MPa, measured at a temperature of about 25 ℃. Polymer fixtures are typically required to be non-conductive.

Although any material having the above-described strength may be used, we have found that curable thermosetting resins are particularly suitable for use in the present invention. Examples of such resins include, for example, epoxy resins, polyimides, melamine resins, urea-formaldehyde resins, polyurethanes, silicone polymers, phenolic resins, and the like. For example, in certain embodiments, the polymer fixture may employ one or more polysiloxanes. The silicon-containing organic groups used in these polymers may contain monovalent hydrocarbon groups and/or monovalent halogenated hydrocarbon groups. Such monovalent groups typically contain 1 to about 20 carbon atoms, preferably 1 to 10 carbon atoms. The following are examples of such groups, but are not limited to these example groups: alkyl groups (such as methyl, ethyl, propyl, pentyl, octyl, undecyl, and octadecyl); cycloalkyl (e.g., cyclohexyl); alkenyl groups (such as vinyl, allyl, butenyl, and hexenyl); aryl groups (e.g., phenyl, tolyl, xylyl, benzyl, and 2-phenylethyl); and halogenated hydrocarbon groups (such as 3,3, 3-trifluoropropyl group, 3-chloropropyl group, and dichlorophenyl group). Generally, at least 50%, more preferably at least 80% of the organic groups are methyl groups. Examples of such methylpolysiloxanes include, for example, polydimethylsiloxane ("PDMS"), polymethylhydrosiloxane (polymethylhydrosiloxane), and the like. Other suitable methyl polysiloxanes include dimethyl diphenyl polysiloxane, dimethyl/methylphenyl polysiloxane, polymethylphenylsiloxane, methylphenyl/dimethyl siloxane, vinyldimethyl-terminated polydimethylsiloxane, vinylmethyl/dimethyl polysiloxane, vinyldimethyl-terminated vinylmethyl/dimethyl polysiloxane, divinylmethyl-terminated polydimethylsiloxane, vinylphenylmethyl-terminated polydimethylsiloxane, dimethylhydrogen-terminated polydimethylsiloxane, methylhydro/dimethyl polysiloxane, methylhydro-terminated methyloctyl polysiloxane, methylhydro/phenylmethyl polysiloxane, and the like.

The organopolysiloxane may also contain one or more polar functional group side groups and/or end groups that impart some degree of hydrophilicity to the polymer, such as hydroxyl, epoxy, carboxyl, amino, alkoxy, methacrylate, or mercapto groups. For example, the organopolysiloxane may include at least one hydroxyl group, and optionally an average of at least two silicon-containing hydroxyl groups per molecule (silanol groups). Examples of such organopolysiloxanes include, for example, dihydroxy polydimethylsiloxane, hydroxy-trimethylsiloxy polydimethylsiloxane, and the like. Other examples of hydroxyl-modified organopolysiloxanes are described in Kleyer et al, U.S. patent application publication 2003/0105207. Alkoxy-modified organopolysiloxanes such as dimethoxypolydimethylsiloxane, methoxy-trimethylsiloxy polydimethylsiloxane, diethoxypolydimethylsiloxane, ethoxy-trimethylsiloxy-polydimethylsiloxane, and the like can also be used. Other suitable organopolysiloxanes are those modified with at least one amino function. Examples of such amino-functional polysiloxanes include, for example, polydimethylsiloxanes bearing diamino-functional groups. Other suitable polar functional groups for organopolysiloxanes are also described in U.S. patent application publication US2010/00234517 to Plantenberg et al.

Epoxy resins are also particularly suitable for use as polymer fixtures. Examples of suitable epoxy resins include, for example, glycidyl ether type epoxy resins such as bisphenol a type epoxy resin, bisphenol F type epoxy resin, novolac epoxy resin, o-cresol novolac epoxy resin, brominated epoxy resin, and biphenyl type epoxy resin, alicyclic epoxy resin, glycidyl ester type epoxy resin, glycidyl amine type epoxy resin, cresol novolac epoxy resin, naphthalene type epoxy resin, aralkyl phenol type epoxy resin, cyclopentadiene type epoxy resin, heterocyclic epoxy resin, and the like. Other suitable conductive adhesive resins (conductive adhesives) are described in U.S. patent application publication Nos. US2006/0038304 to Osako et al and U.S. patent No. US7,554,793 to Chacko.

If desired, a curing agent may also be used in the polymer fixture to help promote curing. The curing agent typically comprises from about 0.1wt% to about 20wt% of the polymer fixture. Examples of curing agents include, for example, ammonia, peroxides, anhydrides, phenolic compounds, silanes, anhydride compounds, and combinations thereof. Specific examples of suitable curing agents are dicyandiamide, 1- (2-cyanoethyl) -2-ethyl-4-methylimidazole, 1-benzyl 2-methylimidazole, ethylcyanopropylimidazole, 2-methylimidazole, 2-phenylimidazole, 2-ethyl-4-methylimidazole, 2-undecylimidazole, 1-cyanoethyl-2-methylimidazole, 2, 4-dicyano-6, 2-methylimidazolyl- (1) -ethyl-s-triazine and 2, 4-dicyano-6, 2-undecylimidazolyl- (1) -ethyl-s-triazine, imidazole salts (e.g. 1-cyanoethyl-2-undecyltrimellitate, salts of maleic acid, maleic, 2-methylimidazole isocyanurate, 2-ethyl-4-methylimidazole tetraphenylborate, 2-ethyl-1, 4-dimethylimidazole tetraphenylborate, and the like). Other useful curing agents include phosphine compounds such as tributylphosphine, triphenylphosphine, tris (dimethoxyphenyl) phosphine, tris (hydroxyphenyl) phosphorus and tris (cyanoethyl) phosphine; phosphorus salts such as tetraphenylphosphonium tetraphenylborate, methyltribuylphosphonium tetraphenylborate, and methyltricyanoethylphosphonium tetraphenylborate); amines such as 2,4, 6-tris (dimethylaminomethyl) phenol, methylbenzylamine, tetramethylbutylguanidine, N-methylpiperazine and 2-dimethylamino-1-pyrroline; ammonium salts, such as triethyltetraphenylammonium borate; diazabicyclo compounds, such as 1, 5-diazabicyclo [5,4,0] -7-undecene, 1, 5-diazabicyclo [4,3,0] -5-nonene and 1, 4-diazabicyclo [2,2,2] -octane; salts of diazabicyclic compounds, such as tetraphenylborate, phenoxide, phenonoloxolac, 2-ethylhexanoate; and so on.

Other additives such as photoinitiators, viscosity modifiers, suspension aids, pigments, stress reducers, coupling agents (e.g., silane coupling agents), non-conductive fillers (e.g., clay, silica, alumina, etc.), stabilizers, and the like may also be used. Suitable photoinitiators include, for example, benzoin methyl ether, benzoin ethyl ether, benzoin n-propyl ether, benzoin isobutyl ether, 2 dihydroxy-2-phenylacetophenone, 2-dimethoxy-2-phenylacetophenone, 2-diethoxy-2-phenylacetophenone, 2-diethoxyacetophenone, benzophenone, 4-dialkylaminobenzophenone (dialkylaminobenzophenone), 4-dimethylaminobenzoic acid, alkyl 4-dimethylaminobenzoates, 2-ethylanthraquinone, xanthones, thioxanthones, 2-chlorothioxanthones, and the like. When these additives are employed, they are generally present in an amount of from about 0.1wt% to about 20wt% of the total composition.

Referring again to fig. 1, for example, one embodiment is shown wherein a monolithic polymer fixture 197 is in contact with the upper surface 181 and the back surface 177 of the capacitor element 120. Although a single block polymer fixture is shown in fig. 1, it should be understood that separate polymer fixtures may be used to accomplish the same function. Indeed, more generally, any number of polymer fixtures may be used to contact any desired surface of the capacitor element. When several polymer fixtures are used, they may contact each other or remain physically separated. For example, in one embodiment, a second polymer fixture (not shown) is employed in contact with the upper surface 181 and the front surface 179 of the capacitor element 120. The first polymer fixture 197 and the second polymer fixture (not shown) may or may not contact each other. In yet another embodiment, the polymer fixture is also in contact with lower surface 183 and/or side surfaces of capacitor element 120, while in contact with other surfaces or in lieu of contact with other surfaces.

Regardless of the application, it is often desirable that the polymeric fixture also contact at least one surface of the housing to help further mechanically stabilize the capacitor element. For example, the polymer fixture may be in contact with the inner surface of one or more of the side walls, outer walls, covers, and the like. For example, in fig. 1, the polymer fixture 197 is in contact with the inner surface 107 of the sidewall 124 and the inner surface 109 of the outer wall 123. While in contact with the housing, it is desirable that at least a portion of the interior cavity defined by the housing remain unoccupied to allow the inert gas to flow through the cavity and limit contact of the solid electrolyte with oxygen. For example, at least about 5% of the cavity volume generally remains unoccupied by the capacitor element and the polymer fixture, and in some embodiments, from about 10% to about 50% of the cavity volume is unoccupied.

In some embodiments, a connecting element may be used within the interior cavity of the housing to facilitate connection with external terminal portions, as described in more detail below. For example, referring again to fig. 1, capacitor assembly 100 can include a connecting member 162 formed of a first portion 167 and a second portion 165. The connection member 162 may be made of a conductive material, such as metal. The first portion 167 and the second portion 165 may be integral or separate components that are connected together either directly or through other conductive elements (e.g., metal). In the illustrated embodiment, the second portion 165 is disposed in a plane that is generally parallel to the longitudinal direction in which the leads 6 extend (e.g., -y direction). The first portion 167 is "upright", i.e. it lies in a plane substantially perpendicular to the longitudinal direction in which the leads 6 extend. In this manner, first portion 167 limits movement of lead 6 in a horizontal direction, enhancing use during useSurface contact and mechanical stability. Insulating material 7 (e.g., Teflon) can be used around the leads 6 if desired^TMA shim).

The first portion 167 may have a mounting area (not shown) connected to the anode lead 6. This region is "U-shaped" for further enhancing the surface contact and mechanical stability of the lead 6. The attachment of the mounting area to the lead 6 may be accomplished using any known technique, such as soldering, laser welding, conductive adhesive bonding, and the like. For example, in one embodiment, the mounting area is laser welded to the anode lead 6. Regardless of the method selected, however, the first portion 167 can maintain the anode lead 6 in a generally horizontal alignment to further enhance the dimensional stability of the capacitor assembly 100.

Referring again to fig. 1, an embodiment of the present invention is shown in which connecting element 162 and capacitor element 120 are connected to anode and cathode terminals 127 and 129 and housing 122, as discussed in more detail below. The housing 122 of this embodiment includes an outer wall 123 and two opposing side walls 124 that define a cavity 126 therebetween that houses the capacitor element 120. The outer wall 123 and the side wall 124 may be formed from one or more layers of metal, plastic, or ceramic materials as described above. Although not required, the anode terminal 127 can include an inner portion 127a and an outer portion 127b, wherein the inner portion 127a is disposed within the casing 122 and electrically coupled to the connecting member 162, and the outer portion 127b is disposed outside the casing 122 and provides a mounting surface 201. Likewise, cathode terminal 129 includes an inner portion 129a and an outer portion 129b, wherein inner portion 129a is positioned within housing 122 and is electrically connected to the solid electrolyte of capacitor element 120, and outer portion 129b is positioned outside housing 122 and provides a mounting surface 203. It should be understood that all of the parts need not be entirely inside or outside the housing. It should be understood that the exterior of the terminal may be discarded if desired.

In the illustrated embodiment, the conductive trace 127c extends along the housing outer wall 123 to connect the inner portion (first zone) 127a and the outer portion (second zone) 127 b. Similarly, a conductive trace 129c extends along the housing outer wall 123 to connect the inner portion (first zone) 127a and the outer portion (second zone) 127 b. The conductive traces and/or terminal areas may be separate or integral. The traces may be located elsewhere than through the housing outer wall, such as outside the outer wall. Of course, the present invention is not limited to the use of conductive traces to form the desired terminals. Generally, the connection of the external terminal portions 127 and 129 to the capacitor element 120 can be accomplished using any known technique, such as soldering, laser welding, conductive adhesive, and the like. For example, in one particular embodiment, the second portion 165 of the connecting element 162 is connected to the anode terminal 127 using a conductive adhesive 131. Similarly, the cathode of capacitor element 120 may be connected to cathode terminal 129 using conductive adhesive 133. The conductive adhesive may be formed of conductive metal particles including a resin composition. The metal particles may be silver, copper, gold, platinum, nickel, zinc, bismuth, and the like. The resin composition may include a thermosetting resin (e.g., an epoxy resin), a curing agent (e.g., an acid anhydride), and a coupling agent (e.g., a silane coupling agent). Suitable conductive adhesives are described in U.S. patent application publication 2006/0038304 to Osako et al.

Once connected as desired, the resulting package is sealed as described above. Referring again to fig. 1, for example, housing 122 may further include a cover 125, with cover 125 being placed over the upper surface of side wall 124 after capacitor elements 120 and polymer fixture 197 are placed within housing 122. The cover 125 may be made of ceramic, metal (e.g., iron, copper, nickel, cobalt, etc., and alloys thereof), plastic, etc. If desired, a sealing element 187 may be placed between the lid 125 and the sidewall 124 to help provide a good seal. For example, in one embodiment, the sealing element may comprise a glass-to-metal seal,(Goodfellow Camridge, Ltd.) and the like. The height of side wall 124 is generally such that cover 125 does not contact any surface of capacitor element 120 so that it is not contaminated. The polymer fixture 197 may or may not contact the cover 125. After being placed at the desired position, using known techniquesSuch as welding (e.g., resistance welding, laser welding, etc.), soldering, etc., to seal the cover 125 to the sidewall 124. As noted above, the sealing is typically performed in the presence of an inert gas, such that the resulting assembly is substantially free of reactive gases, such as oxygen or water vapor.

It should be understood that the illustrated embodiments are exemplary only, and that the present invention may be used with other structures for sealing the capacitor element within the housing. Referring to fig. 3, for example, another embodiment of a capacitor assembly 200 is shown wherein the housing 222 includes an outer wall 123 and a cover 225 defining a cavity 126 therebetween, the capacitor element 120 being contained within the cavity 126, and an optional polymer fixture 197. The cover 225 includes an outer wall 223 integral with at least one side wall 224. For example, in the illustrated embodiment, two opposing sidewalls 224 are shown in cross-section. The outer walls 223 and 123 each extend in the longitudinal direction (-y direction), and are substantially parallel to each other and to the longitudinal direction of the anode lead 6. The side wall 224 extends from the outer wall 223 in a direction substantially perpendicular to the outer wall 123. The distal end 500 of the cover 225 is defined by the outer wall 223 and the proximal end 501 is defined by the lip 253 of the side wall 224. The lip 253 extends from the side wall 224 in a longitudinal direction that is generally parallel to the longitudinal direction of the outer wall 123. The angle between the side wall 224 and the lip 253 can vary, but is typically from about 60 ° to about 120 °, in some embodiments, typically from about 70 ° to about 110 °, and in some embodiments, typically from about 80 ° to about 100 ° (e.g., about 90 °). The lip 253 also defines an outer edge 251 generally perpendicular to the longitudinal direction in which the lip 253 and the outer wall 123 extend. Outer edge 251 is located outside the periphery of sidewall 224 and is generally coplanar with edge 151 of sidewall 123. The lip 253 may be sealed to the outer wall 123 using any known technique, such as welding (e.g., resistance or laser welding), brazing, and the like. For example, in the illustrated embodiment, a sealing member 287 (e.g., a glass-to-metal seal, a gasket,Rings, etc.) to facilitate their attachment. In any event, the above description is usedThe lip portions may make the connection between the components more stable and improve the sealing and mechanical stability of the capacitor assembly.

The embodiments discussed above relate to only a single capacitor element. However, it should also be understood that multiple capacitor elements (e.g., 2,3, etc.) may be enclosed within a single housing. The plurality of capacitor elements may be connected to the housing using different techniques. For example, referring to FIG. 4, a specific embodiment of a capacitor assembly 400 comprising two capacitor elements is shown and will be described in greater detail below. More specifically, capacitor assembly 400 includes a first capacitor element 420a and a second capacitor element 420b, which are electrically connected. In this embodiment, the capacitor elements are placed in alignment with their major surfaces in a parallel configuration to each other. That is, the major surface of capacitor element 420a, defined by its width (-x-direction) and length (-y-direction), is adjacent to the corresponding major surface of capacitor element 420 b. Thus, the major surfaces are generally coplanar. Alternatively, the capacitor element may also be arranged such that: i.e., their major surfaces are not coplanar but are perpendicular to each other in a direction, such as in the-z or-x direction. Of course, the capacitor elements do not need to extend in the same direction.

The capacitor elements 420a and 420b are disposed within a housing 422, the housing 422 including an outer wall 423 and sidewalls 424 and 425 that together define a cavity 426. Although not shown, a lid may be used to cover the upper surfaces of sidewalls 424 and 425 and seal assembly 400, as described above. Optionally, a polymer fixture may be employed to help limit vibration of the capacitor element. For example, in fig. 4, separate polymer fixtures 497a and 497b are adjacent to and in contact with capacitor elements 420a and 420b, respectively. The polymer fixtures 497a and 497b may be located in different locations. In addition, one of the polymer fixtures may be omitted, or more polymer fixtures may be employed. For example, in certain embodiments, it may be desirable to use a polymer fixture between the capacitor elements to further improve mechanical stability.

For example, referring again to FIG. 4, the capacitor elements are shown connected in parallel to a common cathode terminal 429. Capacitor assembly 400 also includes connecting elements 427 and 527 connected to anode leads 406a and 406b of capacitor elements 420a and 420b, respectively. More specifically, the connecting element 427 includes an upright portion 465 connected to an anode terminal (not shown) and a planar portion 463. Also, the connection element 527 includes an upright portion 565 and a planar portion 563 connected to an anode terminal (not shown). Of course, it should be understood that a wide range of other types of connection mechanisms are also possible.

III. terminal

Regardless of the specific structure of the housing and/or capacitor element, or the manner in which they are connected, the exterior of one or more terminals (e.g., pads, sheets, plates, frames, etc.) may be formed in a manner that reduces the likelihood that they will fall off the circuit board. More specifically, the outer portion may extend outwardly beyond the outer edge of the housing surface, thereby increasing the degree of surface contact between the capacitor assembly and the circuit board when mounted. For example, in some embodiments, the lower surface of the casing may have an outer edge defined by a length in the longitudinal direction (e.g., the direction in which the anode lead extends) and a width in the transverse direction. In these embodiments, one or more external terminal portions may extend outward in the lateral direction beyond the outer edge of the lower surface of the housing. Alternatively or in addition to the lateral direction, one or more of the external terminal portions may also extend outward in the longitudinal direction beyond the outer edge.

For example, referring again to fig. 1-2, a specific embodiment is shown wherein the housing 222 defines a lower surface 171. The lower surface 171 has an outer edge 400 defined by a length along the-y axis (e.g., longitudinal) and a width along the-x axis (e.g., lateral). As shown, the external anode terminal portion 127b and the external cathode terminal portion 129b are adjacent the lower surface 171 and extend beyond the edge 400 along the-x axis. Of course, the particular direction of extension is not critical, and portions 127b and 129b may extend beyond edge 400 in other multiple directions, such as along the-y axis. Further, it is also understood that the external terminal portions may extend from other surfaces of the housing than the lower surface, such as the upper surface, the rear surface, and the like. However, at least one external terminal portion is generally provided on a plane parallel to the plane of the housing adjacent thereto. For example, in the embodiment shown in fig. 1-2, the external anode terminal portion 127b and the external cathode terminal portion 129b are disposed on a plane that is generally parallel to the lower surface 171 of the casing 222.

As described above, in the present invention, the extent to which the external anode terminal portions and/or the external cathode terminal portions extend beyond the outer edge of the casing surface is selectively controlled to achieve a balance between increased stability and reduced circuit board footprint. For example, referring again to FIG. 2, the outer anode terminal portion 127b extends beyond the edge 400 a first distance "L₁"(e.g., in the-x direction), and the external cathode terminal portion 129b extends beyond the edge 400 by a second distance" L₂"(e.g., in the-x direction). Distance L₁And L₂May be the same or different. Usually, the distance L₁And/or distance L₂Dimension "L" of surface 171 in the same direction as housing 222 (e.g., wide in the-x direction)₃"is generally from about 0.05 to about 3.0, in some embodiments, from about 0.1 to about 2.5, and, in some embodiments, from about 0.15 to about 2.0. Indeed, in some embodiments, it is desirable for distance L to be₁And/or distance L₂Even greater than dimension L₃Thus, the aforementioned "ratio" is greater than 1. E.g. distance L₁And/or distance L₂Can be from about 0.25 to about 50 millimeters, in some embodiments from about 0.5 to about 40 millimeters, in some embodiments from about 1 to about 20 millimeters, and likewise, the dimension L of the housing₃From about 0.5 to about 40 millimeters, in some embodiments, from about 2 to about 30 millimeters, and in some embodiments, from about 5 to about 25 millimeters.

In the embodiment shown in FIG. 2, each side of the external anode terminal portion 127b extends a distance "L" beyond the edge 400₁", and outerEach side of the partial cathode terminal portion 129b extends beyond the edge 400 by a distance "L₂". In this case, L₁And/or L₂The values of (d) may be the same or different on each side of the respective terminals. It should also be understood that only one side of the terminal extends beyond the edge, if desired.

The external terminal portions 127b and 129b also have a size "W₁"and" W₂"(e.g., in the-y direction), each transverse to the dimension L₁And L₂. For example, the transverse dimension may range from about 0.1 to about 10 millimeters, in some embodiments, from about 0.2 to about 8 millimeters, and in some embodiments, from about 0.5 to about 5 millimeters, while the dimension W of the housing₃(e.g., long in the-y direction) may be from about 2 to about 30 millimeters, in some embodiments, from about 3 to about 20 millimeters, and in some embodiments, from about 4 to about 15 millimeters. The thickness of the terminals may also be selected to enhance stability while still minimizing the thickness of the overall capacitor assembly. For example, the thickness ranges from about 0.1 to about 10 millimeters, in some embodiments, from about 0.2 to about 8 millimeters, and in some embodiments, from about 1 to about 5 millimeters. If desired, the surface of each terminal may be plated with nickel, silver, gold, tin, etc., as is known in the art, to ensure that the finished product can be mounted on a circuit board. In one embodiment, the terminals are plated with bright nickel and bright silver, respectively, and the mounting surface is also plated with a tin solder layer. In another embodiment, a thin outer metal layer (e.g., gold) is electroplated over the base metal layer (e.g., copper alloy) of each terminal to further increase conductivity.

In the embodiment shown in fig. 2, generally, the external terminal portions of the anode and cathode are continuous along the entire lateral dimension of the housing surface 171 (e.g., in the-x direction). However, this is not necessary in all embodiments. For example, referring to FIG. 5, an alternative embodiment is illustrated wherein the external anode terminal portion 627 extends beyond an edge 700 of a surface 771 of the outer shell 772 in one direction (e.g., along the-x axis) and the external cathode terminal portion 629 extends beyond the edge 700 in the opposite direction. Therefore, in this specific embodiment, the external terminal portions 627 and 629 are discontinuous in the lateral dimension direction of the housing surface. A similar embodiment is also shown in fig. 6. In this particular embodiment, the external anode terminal portions 727 are shown as discontinuous across the surface 871 of the housing 872, but extending beyond the edge 800 in two opposite directions (e.g., along the-x axis). Likewise, cathode terminal 729 is shown as discontinuous, but extending beyond edge 800 in two opposite directions along the-x axis. This configuration is particularly beneficial for embodiments employing multiple capacitor elements, as shown in fig. 4 and discussed above.

Further, depending on whether the terminals extend beyond the outer edge in the lateral or longitudinal direction, one or more of the external terminal portions may also be folded or bent upward such that the external terminal portions form a "J" or "L" shape such that the terminals are adjacent to the lower surface and adjacent to the outer wall or side wall of the capacitor, as described in more detail below with reference to fig. 7(a) -9 (b).

Referring now to fig. 7(a) through 8(b), for example, one specific embodiment is shown wherein housing 922 defines a lower surface 971. The lower surface 971 has an outer edge 900 defined by a length along the-y axis (e.g., longitudinal) and a width along the-x axis (e.g., transverse). As shown, the external anode terminal portion 127b and the external cathode terminal portion 129b are adjacent to the lower surface 971 and extend beyond the edge 900 along the-y axis of the longitudinal direction. In fig. 7(a) and 8(a), the external terminal portions 127b and 129b are provided on a plane parallel to their adjacent housing surfaces. For example, in the embodiment shown in fig. 7(a), the external anode terminal portion 127b and the external cathode terminal portion 129b are disposed on a plane generally parallel to the lower surface 971 of the housing 922. In fig. 7(b) and 8(b), the external anode terminal portion 127b and the external cathode terminal portion 129b are also folded or bent so that each terminal forms a "J" shape or an "L" shape against both surfaces of the housing 922. Therefore, at least one side of the anode terminal portion 127b or the cathode terminal portion 129b is perpendicular to the lower surface and is adjacent to the side wall 124 of the case 922. For example, in fig. 7(b) and 8(b), the external anode terminal portion 127b and the external cathode terminal portion 129b are adjacent to the lower surface 971 and the side wall 124 of the housing 922. It is believed that the external anode terminal portion 127b and the external cathode terminal portion 129b contribute to the mechanical stability of the capacitor assembly under extreme conditions.

As described above, in the present invention, the extent to which the external anode terminal portions and/or the external cathode terminal portions extend beyond the outer edge of the housing surface is selectively controlled to achieve a balance between increased stability and reduced circuit board footprint. For example, referring again to fig. 7(a), the external anode terminal portion 127b extends beyond the edge 900 in the longitudinal direction by a first distance "L₁"(e.g., in the-y direction), and the outer cathode terminal portion 129b extends beyond the edge 900 in the longitudinal direction by a second distance" L₂"(e.g., in the-y direction). In this case, L₁And/or L₂The values of (d) may be the same or different on each side of the respective terminals. It should also be understood that only one side of the terminal extends beyond the edge, if desired. Usually, the distance L₁And/or distance L₂Dimension "L" of surface 971 in the same direction as housing 922 (e.g., long in the-y direction)₃"is generally from about 0.05 to about 2, in some embodiments, from about 0.10 to about 1.75, and, in some embodiments, from about 0.15 to about 1.5. In certain embodiments, it is desirable for distance L to be₁And/or L₂Even greater than dimension L₃Thus, the aforementioned "ratio" is greater than 1, while in other embodiments, it is desirable that the distance L be greater than 1₁And/or L₂Less than dimension L₃Thus, the aforementioned "ratio" is less than 1. E.g. distance L₁And/or distance L₂Can be from about 0.25 to about 50 millimeters, in some embodiments, from about 0.50 to about 40 millimeters, in some embodiments, from about 1 to about 30 millimeters, and the dimension L of the housing₃From about 0.5 to about 40 millimeters, in some embodiments, from about 2 to about 30 millimeters, and in some embodiments, from largeAbout 5 to about 25 millimeters.

Further, in fig. 7(a) through 8(b), the height dimension H of the side wall 124 of the housing assembly 922 is shown to be perpendicular to the lower surface 971. Regardless of the value of dimension H, it should be understood that distance L₁And/or L₂May be less than, greater than, or equal to dimension H. For example, when both the external anode terminal portion and the external cathode terminal portion are folded on the side wall 124, the distance L₁And/or L₂The ratio to the dimension H of the side wall 124 of the housing 922 may be from about 0.1 to about 2, such as from 0.15 to about 1.5, such as from 0.2 to about 1.0. Therefore, when the external anode terminal portion 127b and the external cathode terminal portion 129b are folded or bent, the distance L is increased₁And L₂The portion or side shown is adjacent to or in contact with the sidewall 124 and perpendicular to the surface 971, as shown in fig. 7(b) and 8(b), and the terminal portion may extend against the sidewall a distance less than the dimension H of the sidewall 124, as shown in fig. 7(b), a distance equal to the dimension H of the sidewall 124, as shown in fig. 8(b), or beyond the dimension of the sidewall 124 (not shown). In any case, the "J" or "L" shaped structure of the external anode terminal portion 127b and the external cathode terminal portion 129b is formed due to at least one side of the external terminal portion being folded or bent against the side wall 124 of the case 922, which improves the mechanical stability of the disclosed capacitor.

Next, as shown in fig. 8(a), the external terminal portions 127b and 129b also have a lateral dimension "W₁"and" W₂"(e.g., in the-x direction), each perpendicular to the dimension L₁And L₂. The transverse dimension may be greater than, equal to, or less than the shell dimension W₃. For example, W₁And W₂In the range of from about 0.1 to about 30 millimeters, in some embodiments, from about 0.2 to about 20 millimeters, and in some embodiments, from about 0.5 to about 15 millimeters, and the dimension W of the housing₃(e.g., long in the-x direction) may be from about 2 to about 30 millimeters, in some embodiments, from about 3 to about 20 millimeters, and in some embodiments, from about 4 to about 15 millimeters.In the embodiment shown in fig. 8(a), the external cathode terminal portion 129b is generally continuous along the entire lateral dimension of the housing surface 971 (e.g., in the-x direction), while the external anode terminal portion 127b is generally discontinuous along the entire lateral dimension of the surface 971. However, it should be understood that the external anode terminal portion and the external cathode terminal portion can be generally continuous in the entire lateral direction. It should also be understood that the external anode terminal portion and the external cathode terminal portion can be generally discontinuous in the entire lateral direction. The bending and folding of the terminal portions 127b and 129b against the side walls 124 improves the stability of the capacitor under extreme conditions, whether or not the terminal portions are continuous in the entire transverse direction.

Referring now to fig. 9(a) and 9(b), there is shown an embodiment of a capacitor assembly similar to that of fig. 2,5 and 6, except that in fig. 9(b), the outer anode terminal portion 127b and the outer cathode terminal portion 129b extending in a transverse direction (e.g., -x direction) beyond the edge 1000 of the capacitor housing 1022 are folded or bent such that the anode and cathode terminals generally have a "J" shape or an "L" shape where the bent or folded portion or side extends in a direction perpendicular to the surface 1071 against the outer wall 123 of the housing 1022. In this way, the capacitor assembly can provide additional mechanical stability under extreme conditions.

Generally, in fig. 9(a) and 9(b), the height of the outer wall 123 of the housing assembly 1022 is shown as dimension H, which is perpendicular to the lower surface 1071. Regardless of the value of dimension H, it should be understood that distance L₁And/or L₂May be less than, greater than, or equal to dimension H. For example, when both the external anode terminal portion and the external cathode terminal portion are folded on the external wall 123, the distance L₁And/or L₂The ratio to the dimension H of the outer wall 123 of the housing 1022 may be from about 0.1 to about 2, such as from about 0.15 to about 1.5, such as from about 0.2 to about 1.0. Therefore, when the external anode terminal portion 127b and the external cathode terminal portion 129b are folded or bent, the distance L is increased₁And L₂Shown as a portion or side adjacent to or in contact with the outer wall 123 and perpendicular to the surface 1071, as shown in fig. 9(b) and 9 (c) ((b))b) The terminal portion may extend against the outer wall a distance less than the dimension H of the outer wall 123, as shown in fig. 9(b), a distance equal to the dimension H of the outer wall 123, as shown in fig. 9(b), or beyond the dimension of the outer wall 123 (not shown). In any case, since at least one side of the external terminal portion is folded or bent against the outer wall 123 of the case 1022, a "J" type or "L" type structure of the external anode terminal portion 127b and the external cathode terminal portion 129b is formed, which improves the mechanical stability of the disclosed capacitor.

The capacitor assembly of the present invention has good stability and excellent electrical properties even when exposed to high temperature and/or high voltage environments. For example, the capacitor assembly has a relatively high "breakdown voltage" (voltage at which the capacitor fails), such as a voltage of about 35V or greater, in some embodiments about 50V or greater, in some embodiments about 60V or greater, and in some embodiments, from about 60V to about 100V, the breakdown voltage being the voltage measured by increasing the applied voltage in 3V increments until the leakage current reaches 1 mA. Also, the capacitor is also capable of withstanding the relatively high inrush currents common in high voltage applications. For example, the surge current peak is about 2 times or more the rated current, such as about 40A or more, in some embodiments about 60A or more, and in some embodiments, about 120A to about 250A.

Also, the capacitance is about 1 millifarad per square centimeter ("mF/cm)²") or higher, and in some embodiments, about 2mF/cm²Or higher, and in some embodiments, from about 5 to about 50mF/cm²And in some embodiments, from about 8 to about 20mF/cm². The capacitance was measured at an operating frequency of 120Hz and a temperature of 25 ℃. In addition, the capacitor assembly also has a relatively high wet capacitance percentage, resulting in only a small loss and/or fluctuation in capacitance under ambient humidity conditions. This property is quantified as a "percent dry-wet capacitance" and is determined by the following equation:

dry-to-wet capacitance ratio = (1- ([ wet capacitance-dry capacitance ]/wet capacitance)) × 100

For example, the percent dry-wet capacitance of the capacitor assembly of the present invention is about 80% or more, in some embodiments, about 85% or more, in some embodiments, about 90% or more, in some embodiments, about 92% to 100%.

The capacitor assembly has an equivalent series resistance ("ESR") of less than about 50 ohms, in some embodiments less than about 25 ohms, in some embodiments, between about 0.01 and about 10 ohms, and in some embodiments, between about 0.05 and about 5 ohms, measured at an operating frequency of 100 kHz. In addition, leakage current, which generally refers to current flowing from one conductor to a nearby conductor through an insulator, can also be kept at a relatively low level. For example, the standard leakage current of the capacitors of the present invention may have a value of less than about 1 μ Α/μ Ρ ν in some embodiments, less than about 0.5 μ Α/μ Ρ ν in some embodiments, less than about 0.1 μ Α/μ Ρ ν, wherein μ Α is microampere and μ Ρ ν is the product of the rated capacitance and the rated voltage.

As described above, the above electrical properties can be maintained even after aging at high temperature for a long time. For example, these values may be maintained for about 100 hours or more, in some embodiments from about 300 hours to about 3000 hours, and in some embodiments, from about 400 hours to about 2500 hours (e.g., 500 hours, 600 hours, 700 hours, 800 hours, 900 hours, 1000 hours, 1100 hours, 1200 hours, or 2000 hours) at a temperature of from about 100 ℃ to about 250 ℃, in some embodiments, from about 100 ℃ to about 225 ℃, and in some embodiments, from about 110 ℃ to about 225 ℃.

The invention will be better understood from the following examples.

Test program

Vibration test was carried out at 23 ℃ and 125 ℃

The vibration test was performed according to IEC 68-2-6. More specifically, the product was initially attached to a printed circuit board by sn96.5-576 (EFD corporation, 85.4-88.3% by weight tin, 2.5-2.9% by weight silver, 0.4-0.5% by weight copper, and the remainder organic rosin and right-click solvent) solder paste. The circuit board is then mechanically mounted to the vibration table and the part is subjected to the entire frequency range of 10Hz to 2.000Hz in 20 minutes and then back to 10 Hz. This cycle was completed 12 times (36 times total) in each of the orthogonal directions with vibration applied for approximately 12 hours. The amplitude is 3.0mm from 10Hz to higher crossover frequencies, then 20g accelerates to 2.000 Hz.

The test was performed using a Derritron VP85/TW6000 instrument at 23 ℃. + -. 2 ℃. The test was performed using an LDSV850 instrument and a high temperature oven (Kittec) at 125 ℃. + -. 5 ℃. Equivalent Series Resistance (ESR)

The equivalent series resistance can be measured using a Keithley3330 precision LCZ tester with Kelvi n leads at 2.2 volts dc bias and 0.5 volts peak-to-peak sinusoidal signal. The working frequency is 100kHz, and the temperature is 23 +/-2 ℃.

Capacitor with a capacitor element

Capacitance can be measured using a Keithley3330 precision LCZ tester with Kelvin leads at 2.2 volts dc bias and 0.5 volts peak-to-peak sinusoidal signal. The working frequency is 120Hz, and the temperature is 23 +/-2 ℃.

Leakage current

The leakage current ("DCL") was measured using a leakage tester at a temperature of 25 ℃ and after reaching the rated voltage for at least 60 seconds.

Examples of the invention

A tantalum anode (4.80 mm. times.5.25 mm. times.2.60 mm) was anodized to 47 μ F in liquid electrolyte at 118V. Then, a conductive coating was formed by immersing the entire anode in an aqueous solution of manganese (II) nitrate having a different specific gravity, followed by decomposition at 250 ℃. The parts were then coated with graphite and silver. And finishing the assembly process by adopting a copper-based lead frame material. A single cathode connection element is connected to the lower surface of the capacitor element using a silver adhesive. The tantalum wire of the capacitor element is then laser welded to the anode connection element. The bottom surface in the ceramic shell is provided with a gold-plated bonding pad. To increase the availability of solder to the surface area of the circuit board, four (4) external copper terminals (13.00 mm long, 2.00mm wide, 0.1mm thick) were connected to each gold plated pad on the housing using solder Ag72 (71.0% -73.0% silver by weight and 27.0% -29.0% copper by weight).

The anode connecting elements of the lead frame were then welded to gold anode terminals and the cathode connecting elements were glued to gold cathode terminals, which were located in a ceramic housing 11.00mm long, 12.00mm wide and 5.40mm thick. The adhesive used for the connection was silver paste (EPO-Tek E3035), and the adhesive was used only between the lead frame portion and the gold-plated pad. After drying at 150 ℃ for 2 hours, (B) polymer immobilizate736 heat resistant sealant) was coated over the anode and cathode portions of the capacitor element and polymerized at 23 c for 24 hours and then dried at 165 c for 1.5 hours. Then put on the top of the containerAnd (7) a cover. The resulting assembly was placed in a welding chamber and purged with nitrogen for 120 minutes, and then seam welding was performed between the seal ring and the lid. 40 parts were made in this manner and then subjected to electrical performance testing (i.e., leakage current, ESR, and capacitance after aging). The median values measured after the vibration tests at 23 ℃ and 125 ℃ are as follows.

These and other modifications and alterations to the invention may be practiced by those skilled in the art, without departing from the spirit and scope of the invention. Additionally, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, it will be appreciated by persons skilled in the art that the present invention has been described by way of example only, and not by way of limitation, as further described in the claims.

Claims (21)

1. A capacitor assembly, comprising:

a capacitor element comprising an anode formed of an anodized sintered porous body and a solid electrolyte coated on the anode;

a housing defining an interior cavity in which the capacitor element is disposed and hermetically sealed, wherein the interior cavity has an atmosphere containing an inert gas, wherein the housing comprises a surface having a dimension in a longitudinal direction and a dimension in a transverse direction, the surface further defining an outer edge;

an anode terminal electrically connected to the anode body, the anode terminal including an external anode terminal portion adjacent to the surface of the case; and

a cathode terminal electrically connected to the solid electrolyte, the cathode terminal including an external cathode terminal portion adjacent to the surface of the housing;

wherein the external anode terminal portion, the external cathode terminal portion, or both extend outward in the lateral direction beyond an outer edge of the can surface by a first distance, wherein a ratio of the first distance to a dimension of the can surface in the lateral direction is from 0.05 to 3.0.

2. The capacitor assembly according to claim 1 wherein the external anode terminal, the external cathode terminal, or both are disposed on a plane substantially parallel to the surface of the case.

3. The capacitor assembly according to claim 1 wherein the outer anode terminal portion extends outwardly beyond an outer edge of the can surface by the first distance.

4. The capacitor assembly according to claim 1 wherein the ratio of the first distance to the dimension of the housing surface in the transverse direction is from 0.10 to 2.5.

5. The capacitor assembly according to claim 1 wherein the first distance is greater than a dimension of the housing in a lateral direction.

6. The capacitor assembly according to claim 1 wherein the first distance is from 0.5 to 40 millimeters and the dimension of the housing surface in the transverse direction is from 2 to 30 millimeters.

7. The capacitor assembly according to claim 1, wherein each side of the external anode terminal portion extends outwardly beyond an outer edge of the case surface.

8. The capacitor assembly according to claim 1 wherein the external cathode terminal portion extends outwardly in a lateral direction a second distance beyond an outer edge of the case surface.

9. The capacitor assembly according to claim 8, wherein the ratio of the second distance to the dimension of the housing surface in the lateral direction is from 0.05 to 3.0, and preferably from 0.10 to 2.5.

10. The capacitor assembly according to claim 8 wherein the second distance is greater than a dimension of the housing in a lateral direction.

11. The capacitor assembly according to claim 8 wherein the second distance is from 0.5 to 40 millimeters and the dimension of the housing surface in the transverse direction is from 2 to 30 millimeters.

12. The capacitor assembly according to claim 8 wherein each side of the external cathode terminal portion extends outwardly beyond an outer edge of the housing surface.

13. The capacitor assembly according to claim 1 wherein the external anode terminal portion and the external cathode terminal portion each extend outwardly beyond an outer edge.

14. The capacitor assembly according to claim 1 wherein the external cathode terminal, the external anode terminal, or both pass through a lateral dimension of the case surface in a discontinuous manner.

15. The capacitor assembly according to claim 1, wherein the porous body is formed of an oxide powder of tantalum or an oxide powder of niobium.

16. The capacitor assembly of claim 1, wherein the inert gas comprises from 50wt% to 100wt% of the gas powder atmosphere.

17. The capacitor assembly of claim 1 wherein the housing is fabricated from metal, plastic, ceramic, or a combination thereof.

18. The capacitor assembly of claim 1, further comprising a lead extending from the anode porous body in the longitudinal direction, wherein the lead is positioned in the internal cavity of the housing.

19. The capacitor assembly according to claim 18 further comprising a connecting member including a first portion substantially perpendicular to the longitudinal direction of the anode lead and connected to the anode lead.

20. The capacitor assembly according to claim 19, wherein the connecting member further comprises a second portion substantially parallel to a longitudinal direction in which the anode lead extends.

21. The capacitor assembly according to claim 20, wherein the second portion is located in the housing and is electrically connected with the external anode terminal portion.