Patent Application
20160379760
The present invention relates to a wound press fit capacitor. More specifically, the present invention relates to a wound press fit capacitor comprising a spacer thereby eliminating any separation between the body of the capacitor and a printed circuit board with the capacitor mounted thereon.
Wound capacitors are widely used throughout industry and are well known to those of skill in the art. Wound capacitors are typically encased in a housing, typically a cylindrical housing, wherein a deck is engaged with the housing to seal the components within the housing. Press fit pins extend from the deck in an arrangement suitable to mate with sockets of the printed circuit board. The press fit pins include a stand-off and the stand-off prohibits the capacitor body from sitting flush on the printed circuit board. Due to the separation between the capacitor and printed circuit board the capacitor attachment is insecure and may become dislodged.
There have been many efforts to redesign printed circuit boards and wound capacitors to alleviate the problems of dislodging but none have proven satisfactory. Provided herein is a solution which allows the capacitor to be securely mounted while minimizing separation between the capacitor body and printed circuit board thereby providing a stable engagement.
It is an object of the invention to provide an improved capacitor.
It is another object of the invention to provide a wound capacitor encased in a housing wherein a spacer is attached to the housing and the spacer allows the body of the capacitor to be in contact with a printed circuit board when mounted to the printed circuit board.
A particular feature of the claimed invention is the ability to provide an improved capacitor with minimal alteration of manufacturing facilities and processes.
These and other embodiments, as will be realized, are provided in a capacitor comprising a housing and a wound capacitive couple in the housing wherein the wound capacitive couple comprises an anode with a dielectric thereon, a cathode, an electrolyte between the cathode and the dielectric, an anode lead in electrical contact with the anode and a cathode lead in electrical contact with the cathode. A deck is secured to the housing and encases the wound capacitive couple in the housing. An anode press fit pin is on the deck and in electrical contact with the anode lead wherein the anode press fit pin comprises an anode riser and an anode compression pin extending from the anode riser opposite the deck. A cathode press fit pin is on the deck and in electrical contact with the cathode lead wherein the cathode press fit pin comprises a cathode riser and a cathode compression pin extending from the cathode riser opposite the deck. A spacer is attached to the housing wherein the spacer comprises a central void wherein the anode press fit pin and cathode press fit pin extend through the void and wherein said spacer extends away from the deck.
The instant invention is related to an improved capacitor and electronic device comprising the improved capacitor. More specifically, the present invention is related to a wound capacitor contained in a housing wherein the housing can sit flush on a printed circuit board when mounted thereon.
The invention will be described with reference to the figures which form an integral non-limiting component of the disclosure. Throughout the figures similar elements will be numbered accordingly.
The advantage of the invention will be described with reference to
An embodiment of the invention will be illustrated with reference to
An embodiment of the invention is illustrated in bottom perspective schematic view in
An embodiment of the invention will be described with reference to
An embodiment of the invention will be described with reference to
The anode is a conductor, preferably a metal, and more preferably a valve metal, with a dielectric thereon preferably in the form of a foil. While not limited thereto the dielectric is preferably an oxide of the anode metal. Particularly preferred anodes are selected from the group consisting of tantalum, aluminum, niobium, titanium, zirconium, hafnium, alloys of these elements and conductive oxides thereof such as NbO. Most preferably, the anode is aluminum.
The dielectric is a non-conductive layer which is not particularly limited herein. The dielectric may be a metal oxide or a ceramic material. A particularly preferred dielectric is the oxide of the anode material due to the simplicity of formation and ease of use. The dielectric layer is preferably an oxide of a valve metal as further described herein. The dielectric is preferably formed by dipping the anode into an electrolyte solution, referred to as a forming electrolyte, and applying a positive voltage to the anode. Forming electrolytes for the oxide formation are not particularly limited herein but exemplary materials can include ethylene glycol; polyethylene glycol dimethyl ether as described in U.S. Pat. No. 5,716,511; alkanolamines and phosphoric acid, as described in U.S. Pat. No. 6,480,371; polar aprotic solvent solutions of phosphoric acid as described in U.K. Pat. No. GB 2,168,383 and U.S. Pat. No. 5,185,075; complexes of polar aprotic solvents with protonated amines as described in U.S. Pat. No. 4,812,951 or the like. Electrolytes for formation of the dielectric on the anode including aqueous solutions of dicarboxylic acids, such as ammonium adipate, are also known. Other materials may be incorporated into the dielectric such as phosphates, citrates, etc. to impart thermal stability or chemical or hydration resistance.
The cathode is not particularly limited herein and may be in the form of a meal foil or a metal coating in some embodiments. Metals are preferable and, in one embodiment, the cathode foil may comprise the same material as the anode foil except the cathode preferably lacks formed dielectric.
The separator is not particularly limited herein. Exemplary materials for demonstration of the invention include nonwoven fabric containing cellulose, kraft, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, nylon, aromatic polyamide, polyimide, polyamide-imide, polyether imide, rayon, glass and the like.
The electrolyte may comprise a solid electrolyte, a liquid electrolyte or a combination thereof. Particularly preferably solid electrolytes are selected from manganese dioxide and conductive polymer. A particularly preferred conductive polymer is selected from polythiophene, polyaniline, polypyrrole or their derivatives.
A particularly preferred conducting polymer is illustrated in Formula I:
R1 and R2 of Formula 1 are chosen to prohibit polymerization at the β-site of the ring. It is most preferred that only α-site polymerization be allowed to proceed. Therefore, it is preferred that R1 and R2 are not hydrogen. More preferably, R1 and R2 are α-directors. Therefore, ether linkages are preferable over alkyl linkages. It is most preferred that the groups are small to avoid steric interferences. For these reasons R1 and R2 taken together as —O—(CH2)2—O— is most preferred.
In Formula 1, X is S or N and most preferable X is S.
R1 and R2 independently represent linear or branched C1-C16 alkyl or C2-C18 alkoxyalkyl; or are C3-C8 cycloalkyl, phenyl or benzyl which are unsubstituted or substituted by C1-C6 alkyl, C1-C6 alkoxy, halogen or OR3; or R1 and R2, taken together, are linear C1-C6 alkylene which is unsubstituted or substituted by C1-C6 alkyl, C1-C6 alkoxy, halogen, C3-C8 cycloalkyl, phenyl, benzyl, C1-C4 alkylphenyl, C1-C4 alkoxyphenyl, halophenyl, C1-C4 alkylbenzyl, C1-C4 alkoxybenzyl or halobenzyl, 5-, 6-, or 7-membered heterocyclic structure containing two oxygen elements. R3 preferably represents hydrogen, linear or branched C1-C16 alkyl or C2-C18 alkoxyalkyl; or are C3-C8 cycloalkyl, phenyl or benzyl which are unsubstituted or substituted by C1-C6 alkyl.
The conducting polymer is preferably chosen from polypyrroles, polyanilines, polythiophenes and polymers comprising repeating units of Formula I, particularly in combination with organic sulfonates. A particularly preferred polymer is 3,4-polyethylene dioxythiophene (PEDT).
The conducting polymer dispersion preferably comprises polymers with a particle size of no more than 100 nm. Above about 100 nm the film formed on the cathode is not adequate. It is preferable that the particles have a particle size of at least 0.5 nm. Below about 0.5 nm the particles have the potential of entering the interstitial surface into regions of poor dielectric. The particle size is preferably at least 5 to no more than 20 nm.
The solid electrolyte may includes at least one additive selected from fibers, dopants, crosslinkers, binders and nanoparticles wherein the additive comprises the reactive group of the solid electrolyte.
Particularly preferred nanoparticles are functionalized nanoparticles wherein the surface of the nanoparticles has been derivatized to include reactive groups.
The solid electrolyte may include fibers suitable for facilitating absorption of the liquid electrolyte. Particularly suitable fibers are fibers and nanofibers prepared from polymers such as polyacrylonitrile, cellulose, polyethylene oxide, polymethylmethacrylate, polyamide, polyaniline, polyvinyl alcohol, nanofibers derived from cellulose, nanofibers electrolspun from conducting polymers such as polyaniline, polythiophene, polypyrrole, etc. Fibers with a length of no more than 100 nm and diameter of no more than 50 nm are preferred. Microfibers or nanofibers prepared by milling can also be used. Hollow fibers and fibers with higher electrolyte absorption properties are preferred.
As typically employed in the art, various dopants can be incorporated into the polymer during the polymerization process. Dopants can be derived from various acids or salts, including aromatic sulfonic acids, aromatic polysulfonic acids, organic sulfonic acids with hydroxy groups, organic sulfonic acids with carboxylhydroxyl group, alicyclic sulfonic acids and benzoquinone sulfonic acids, benzene disulfonic acid, sulfosalicylic acid, sulfoisophthalic acid, camphorsulfonic acid, benzoquinone sulfonic acid, dodecylbenzenesulfonic acid, toluenesulfonic acid. Other suitable dopants include sulfoquinone, anthracenemonosulfonic acid, substituted naphthalenemonosulfonic acid, substituted benzenesulfonic acid or heterocyclic sulfonic acids as exemplified in U.S. Pat. No. 6,381,121, which is included herein by reference thereto. In one embodiment the dopants comprise a solid electrolyte reactive group.
Binders can be also incorporated into the conductive polymer layer if desired. Suitable binders include poly(vinyl acetate), polycarbonate, poly(vinyl butyrate), polyacrylates, polymethacrylates, polystyrene, polyacrylonitrile, poly(vinyl chloride), polybutadiene, polyisoprene, polyethers, polyesters, silicones, and pyrrole/acrylate, vinylacetate/acrylate and ethylene/vinyl acetate copolymers. In one embodiment the binder comprises a solid electrolyte reactive group.
The conductive polymer, binder, dopants or other components of the solid electrolyte comprise reactive groups such as epoxy, hydroxyl, amino, carboxylic, urethane, phosphate, silane, isocyanate, cyanate, nitro, peroxy, phosphio, phosphono, sulfonic acid, sulfone, nitro, acrylate, imide, amide, carboxyl, carboxylic anhydride, silane, oxazoline, (meth)acrylates, vinyls, maleates and maleimides itaconates, allyl alcohol esters, dicyclo-pentadiene-based unsaturations, unsaturated C12-C22 fatty esters or amides, carboxylic acid salts or quaternary ammonium salts which can be crosslinked with reactive groups on the liquid electrolyte. The liquid electrolyte comprises electrolytes solvents, anions, electrolytes and other additives with reactive groups such as epoxy, hydroxyl, amino, carboxylic, urethane, phosphate, silane, isocyanate, cyanate, nitro, peroxy, phosphio, phosphono, sulfonic acid, sulfone, nitro, acrylate, imide, amide, carboxyl, carboxylic anhydride, silane, oxazoline, (meth)acrylates, vinyls, maleates and maleimides itaconates, allyl alcohol esters, dicyclo-pentadiene-based unsaturations, unsaturated C12-C22 fatty esters or amides, carboxylic acid salts or quaternary ammonium salts which can be crosslinked with the reactive groups of the solid electrolyte. By crosslinking the liquid electrolyte with the solid electrolyte the electrolyte of the liquid electrolyte is still mobile yet the other components of the liquid electrolyte are more difficult to remove from the electrolyte thereby increasing the performance in higher temperatures.
At least one component of the liquid electrolyte comprises components with reactive groups otherwise, any conventionally known electrolytic solution may be employed. Preferably, however, the liquid electrolytic comprises solvents, such as non-aqueous solvents or aprotic solvents, an organic salt, cations, anions, electrolytes and other compounds. Particularly preferred additives for the liquid electrolyte include ethers, amides, oxazolidinones, nitriles, glycols, glymes, glycerols, lactones, carbonates, sulfones or polyols.
In the liquid electrolyte the organic salt refers to a salt in which at least one of the base and the acid that are constituent elements of the salt is organic. Gamma-butyrolactone or sulfolane, or a mixture thereof, are particularly suitable non-aqueous solvents with high reliability and a low specific resistance. Organic amine salts are suitable for demonstration of the invention. Organic amine salt refers to a salt of an organic amine and an organic or inorganic acid. Among organic amine salts, a salt of an organic amine and an organic acid is preferably used, and examples thereof include, triethylamine borodisalicylate, ethyldimethylamine phthalate, mono 1,2,3,4-tetramethylimidazolinium phthalate, mono 1,3-dimethyl-2-ethylimidazolinium phthalate, and a mixture of them.
Particularly preferred additives for the liquid electrolyte include polyols, glycerines, polyethylene glycols, poly(ethylene glycol) diacrylates, tetramethyl ammonium phthalates, γ-butyrolactones, ethylated γ-butyrolactones, propylated γ-butyrolactones, and β-propiolactones, dimethoxyethanes (DME), diglymes (diethylene glycol dimethyl ethers), triglymes (triethylene glycol dimethyl ethers), ethylene glycol diethyl ethers (DEE), and diethylene glycol diethyl ethers, polyethylene glycol dimethyl ethers, and at least one other organic solvent. Other additives include hyperbranched polyglycidol, hyperbranched polyalkylene glycols, poly(allyl glycidyl ether), poly(ethoxy ethyl glycidyl ether), copolymers of methyl glycidyl ether and allyl glycidyl ether, copolymers of methyl glycidyl ether and n-butyl glycidyl ether, hyperbranched copolymers comprising polymerizing glycidol of glycidyl ether monomer such as methyl glycidyl ether, poly(ethylene glycol) methyl ether acrylate, methoxypolyethylene glycol amine, O-(carboxymethyl)-O′-methylpolyethylene glycol, methoxy poly(ethylene glycol), polyethylene glycol monomethyl ether, methoxypolyethylene glycol maleimide, and poly(ethylene glycol) methyl ether methacrylate.
Examplary aprotic solvents in the liquid electrolyte include: ethers, amides, oxazolidinones, lactones, nitriles, carbonates, sulfones, and other organic solvents. Examplary ethers include: monoethers, such as ethylene glycol monobutyl ether, ethylene glycol monophenyl ether, tetrahydrofuran, and 3-methyltetrahydrofuran, etc.; diethers, such as ethylene glycol dimethyl ether, ethylene glycol diethyl ether, diethylene glycol monomethyl ether, and diethylene glycol monoethyl ether, etc.; and triethers, such as diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, etc. Examples amides include: formamides, such as N-methylformamide, N,N-dimethylformamide, N-ethylformamide, and N,N-diethylformamide, etc.; acetamides, such as N-methylacetamide, N,N-dimethylacetamide, N-ethylacetamide, and N,N-diethylacetamide, etc.; propionamides, such as N,N-dimethylpropionamide, etc.; pyrrolidones, such as N-methylpyrrolidone, and N-ethylpyrrolidone, etc.; and hexamethyl phosphoryl amide, etc. Examples oxazolidinones include N-methyl-2-oxazolidinone, 3,5-dimethyl-2-oxazolidinone, etc. Examplary lactones include γ-butyrolactone, α-acetyl-γ-butyrolactone, β-butyrolactone, γ-valerolactone, and δ-valerolactone, etc. Examplary nitriles include: acetonitrile, propionitrile, butyronitrile, acrylonitrile, methacrylonitrile, and benzonitrile, etc. Examplary carbonates include: ethylene carbonate, propylene carbonate, butylene carbonate, dimethyl carbonate, and diethyl carbonate, etc. Examplary sulfones include: sulfolane, and dimethyl sulfone, etc. Examples other organic solvents include: 1,3-dimethyl-2-imidazolidinone, dimethyl sulfoxide, aromatic solvents (toluene, xylene, etc.), and paraffin solvents (normal paraffin, isoparaffin, etc.), etc.
Aprotic solvents may be used alone or in combinations of two or more solvents in the liquid electrolyte. Among them, lactone and sulfone are preferred, γ-butyrolactone and sulfolane are more preferred, and γ-butyrolactone is particularly preferred.
In one embodiment the solvent has a boiling point of higher than 200° C. and a dielectric constant of higher than 35.
The liquid electrolyte may contain a cation represented by Formula II and an anion.
In Formula II, R1 to R3 are each C1-3 alkyl, and R4 to R7 are each C1-3 alkyl or a hydrogen atom. Examples of the C1-3 alkyl include: methyl, ethyl, n-propyl and isopropyl.
Exemplary cations include: 1,2,3,4-tetramethylimidazolinium, 1,3,4-trimethyl-2-ethylimidazolinium, 1,3-dimethyl-2,4-diethylimidazolinium, 1,2-dimethyl-3,4-diethylimidazolinium, 1-methyl-2,3,4-triethylimidazolinium, 1,2,3,4-tetraethyl-imidazolinium, 1,2,3-trimethylimidazolinium, 1,3-dimethyl-2-ethylimidazolinium, 1-ethyl-2,3-dimethylimidazolinium, and 1,2,3-triethylimidazolinium, etc. with 1,2,3,4-tetramethylimidazolinium and 1-ethyl-2,3-dimethylimidazolinium being more preferred.
Exemplary anions in the liquid electrolyte include the anions of various organic acids and/or inorganic acids commonly used in electrolytic solutions. In the case of an organic acid and/or inorganic acid having a valence of two or more, the anion is preferably a monoanion.
The organic acid and inorganic acid are exemplified by carboxylic acids, phenols, mono- and di-alkyl phosphates containing C1-15 alkyl, sulfonic acids, inorganic acids, and others. Exemplary carboxylic acids include: C2-15 polycarboxylic acid having a valence of 2 to 4 including: aliphatic polycarboxylic acids, such as saturated polycarboxylic acids, particularly oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, superic acid, azelaic acid, and sebacic acid, etc., and unsaturated polycarboxylic acids particularly maleic acid, fumaric acid, and itaconic acid, etc., aromatic polycarboxylic acids, such as phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, and pyromellitic acid, etc.; and S-containing polycarboxylic acids, such as thiodibropionic acid, etc; C2-20 hydroxycarboxylic acid including aliphatic hydroxycarboxylic acids, such as glycolic acid, lactic acid, tartaric acid, and castor oil fatty acid, etc.; aromatic hydroxycarboxylic acid, such as salicylic acid; and mandelic acid, etc; C1-30 monocarboxylic acid including aliphatic monocarboxylic acids, such as saturated monocarboxylic acids including formic acid, acetic acid, propionic acid, butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, ularic acid, myristic acid, stearic acid and behenic acid, etc.), unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid and oleic acid, etc.; and aromatic monocarboxylic acids, such as benzoic acid, cinnamic acid, and naphthoic acid, etc. Exemplary phenols include monohydric phenol including phenols and naphthols including phenol, C1-15 alkyl phenols such as cresol, xylenol, ethylphenol, n- or isopropylphenol, and isododecylphenol, etc., methoxyphenols such as eugenol, and guaiacol, etc., α-naphthol, β-naphthol, and cyclohexylphenol, etc., polyhydric phenols including catechol, resorcin, pyrogallol, phloroglucin, bisphenol A, bisphenol F, and bisphenol S, etc. Exemplary Mono- and di-alkyl phosphates containing C1-15 alkyl include mono- and di-methyl phosphates, mono- and di-ethyl phosphates, mono- and di-isopropyl phosphates, mono- and di-butyl phosphates, mono- and di-(2-ethylhexyl) phosphates, mono- and di-isodecyl phosphates, etc. Exemplary sulfonic acids include: C1-15 alkyl benzenesulfonic acid such as p-toluenesulfonic acid, nonylbenzenesulfonic acid, and dodecylbenzenesulfonic acid, etc., sulfosalicylic acid, methanesulfonic acid, and trifluoromethanesulfonic acid, etc. Exemplary inorganic acids include: phosphoric acid, tetrafluoroboric acid, perchloric acid, hexafluorophosphoric acid, hexafluoroantimonic acid, and hexafluoroarsenic acid, etc. Other examples include imide anion of trifluoromethane sulfonylimide or the like, and methide anion of trifluoromethane sulfonylmethide or the like.
The electrolyte in the liquid electrolyte is represented by a combination of the cation and the anion, preferably including one from the following: 1,2,3,4-tetramethylimidazolinium/phthalate monoanion, 1-ethyl-2,3-dimethylimidazolinium/phthalate monoanion, 1,2,3,4-tetramethylimidazolinium/maleate monoanion, 1-ethyl-2,3-dimethylimidazolinium cation/maleate monoanion, 1,2,3,4-tetramethylimidazolinium/diethylphosphate anion, 1-ethyl-2,3-dimethylimidazolinium cation/diethylphosphate anion, 1,2,3,4-tetramethylimidazolinium/dibutylphosphate anion, 1-ethyl-2,3-dimethylimidazolinium cation/dibutylphosphate anion, 1,2,3,4-tetramethylimidazolinium/diisopropylphosphate anion, and 1-ethyl-2,3-dimethylimidazolinium cation/diisopropylphosphate anion and most preferably selected from 1,2,3,4-tetramethylimidazolinium/phthalate monoanion, 1-ethyl-2,3-dimethylimidazolinium/phthalatemonoanion, 1,2,3,4-tetramethylimidazolinium/maleate monoanion, and 1-ethyl-2,3-dimethylimidazolinium cation/maleate monoanion.
The concentration of the organic salt in the non-aqueous solvent is not limited to a particular concentration, and a usually employed concentration may appropriately be employed. The concentration may be for example 5 to 50 wt %.
A crosslinker is a material which forms an intermolecular bond with, or by, the reactive group of the solid electrolyte with a reactive group of the liquid electrolyte. Particularly preferred crosslinkers include silanes such as glycidyl silane and organofunctional silanes, epoxides, ethers such as glycidyl ether, epoxy crosslinkers and hydrophilic coupling agents.
The invention has been described with reference to preferred embodiments without limit thereto. One of skill in the art would realize additional embodiments and improvements which are within the scope of the invention as more specifically set forth in the claims appended hereto.
This application claims the benefit of priority under 35 U.S.C. section 119 to pending U.S. Provisional Patent Application No. 62/183,897 filed on Jun. 24, 2015 which is entirety incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62183897 | Jun 2015 | US |
