WO2014066817A1 - Solid electrolytic capacitor with high temperature leakage stability - Google Patents
Solid electrolytic capacitor with high temperature leakage stability Download PDFInfo
- Publication number
- WO2014066817A1 WO2014066817A1 PCT/US2013/066913 US2013066913W WO2014066817A1 WO 2014066817 A1 WO2014066817 A1 WO 2014066817A1 US 2013066913 W US2013066913 W US 2013066913W WO 2014066817 A1 WO2014066817 A1 WO 2014066817A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- solid electrolytic
- electrolytic capacitor
- layer
- forming
- cathode
- Prior art date
Links
- 239000003990 capacitor Substances 0.000 title claims abstract description 141
- 239000007787 solid Substances 0.000 title claims abstract description 94
- 238000000034 method Methods 0.000 claims abstract description 49
- 229910052751 metal Inorganic materials 0.000 claims description 79
- 239000002184 metal Substances 0.000 claims description 79
- 230000000903 blocking effect Effects 0.000 claims description 43
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 38
- 230000007704 transition Effects 0.000 claims description 36
- NUJOXMJBOLGQSY-UHFFFAOYSA-N manganese dioxide Chemical compound O=[Mn]=O NUJOXMJBOLGQSY-UHFFFAOYSA-N 0.000 claims description 20
- 229910052759 nickel Inorganic materials 0.000 claims description 19
- 238000007747 plating Methods 0.000 claims description 19
- 239000000463 material Substances 0.000 claims description 18
- 229910052709 silver Inorganic materials 0.000 claims description 18
- 239000004332 silver Substances 0.000 claims description 18
- 229920000642 polymer Polymers 0.000 claims description 11
- 238000005979 thermal decomposition reaction Methods 0.000 claims description 8
- 229910052717 sulfur Inorganic materials 0.000 claims description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 4
- 239000011593 sulfur Substances 0.000 claims description 4
- 239000000919 ceramic Substances 0.000 claims 3
- 239000010410 layer Substances 0.000 description 223
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 59
- 229910052799 carbon Inorganic materials 0.000 description 53
- 239000011248 coating agent Substances 0.000 description 17
- 238000000576 coating method Methods 0.000 description 17
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 15
- 229910052715 tantalum Inorganic materials 0.000 description 15
- 230000002209 hydrophobic effect Effects 0.000 description 13
- 229920001609 Poly(3,4-ethylenedioxythiophene) Polymers 0.000 description 12
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 11
- 229920001940 conductive polymer Polymers 0.000 description 9
- 239000003792 electrolyte Substances 0.000 description 9
- 239000000243 solution Substances 0.000 description 9
- 239000000853 adhesive Substances 0.000 description 8
- 230000001070 adhesive effect Effects 0.000 description 8
- 238000009713 electroplating Methods 0.000 description 8
- -1 polypyrol Polymers 0.000 description 8
- 239000011347 resin Substances 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 230000008901 benefit Effects 0.000 description 6
- 239000011230 binding agent Substances 0.000 description 6
- 239000004020 conductor Substances 0.000 description 6
- 230000036961 partial effect Effects 0.000 description 6
- 239000007784 solid electrolyte Substances 0.000 description 6
- 230000015572 biosynthetic process Effects 0.000 description 5
- 238000007598 dipping method Methods 0.000 description 5
- 239000011888 foil Substances 0.000 description 5
- 239000002245 particle Substances 0.000 description 5
- 229920000767 polyaniline Polymers 0.000 description 5
- 229920000728 polyester Polymers 0.000 description 5
- 238000006116 polymerization reaction Methods 0.000 description 5
- 229920001296 polysiloxane Polymers 0.000 description 5
- 229920000123 polythiophene Polymers 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 4
- 239000002019 doping agent Substances 0.000 description 4
- 238000005530 etching Methods 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 229910021645 metal ion Inorganic materials 0.000 description 4
- 229920000128 polypyrrole Polymers 0.000 description 4
- 238000005507 spraying Methods 0.000 description 4
- 125000004169 (C1-C6) alkyl group Chemical group 0.000 description 3
- 125000006552 (C3-C8) cycloalkyl group Chemical group 0.000 description 3
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 239000004593 Epoxy Chemical class 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid group Chemical class C(C=C)(=O)O NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 3
- 239000012790 adhesive layer Substances 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 125000001797 benzyl group Chemical group [H]C1=C([H])C([H])=C(C([H])=C1[H])C([H])([H])* 0.000 description 3
- 239000006229 carbon black Substances 0.000 description 3
- 239000002322 conducting polymer Substances 0.000 description 3
- 238000010276 construction Methods 0.000 description 3
- 229920001577 copolymer Polymers 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 238000002955 isolation Methods 0.000 description 3
- 230000000670 limiting effect Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 150000002739 metals Chemical class 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 125000001997 phenyl group Chemical group [H]C1=C([H])C([H])=C(*)C([H])=C1[H] 0.000 description 3
- 238000003825 pressing Methods 0.000 description 3
- 229920005573 silicon-containing polymer Polymers 0.000 description 3
- 239000002904 solvent Substances 0.000 description 3
- 150000003481 tantalum Chemical class 0.000 description 3
- 125000004191 (C1-C6) alkoxy group Chemical group 0.000 description 2
- ROLAGNYPWIVYTG-UHFFFAOYSA-N 1,2-bis(4-methoxyphenyl)ethanamine;hydrochloride Chemical compound Cl.C1=CC(OC)=CC=C1CC(N)C1=CC=C(OC)C=C1 ROLAGNYPWIVYTG-UHFFFAOYSA-N 0.000 description 2
- XQUPVDVFXZDTLT-UHFFFAOYSA-N 1-[4-[[4-(2,5-dioxopyrrol-1-yl)phenyl]methyl]phenyl]pyrrole-2,5-dione Chemical compound O=C1C=CC(=O)N1C(C=C1)=CC=C1CC1=CC=C(N2C(C=CC2=O)=O)C=C1 XQUPVDVFXZDTLT-UHFFFAOYSA-N 0.000 description 2
- QOIXLGYJPBDQSK-UHFFFAOYSA-N 3,6-dioxocyclohexa-1,4-diene-1-sulfonic acid Chemical class OS(=O)(=O)C1=CC(=O)C=CC1=O QOIXLGYJPBDQSK-UHFFFAOYSA-N 0.000 description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 description 2
- 239000004642 Polyimide Substances 0.000 description 2
- KAESVJOAVNADME-UHFFFAOYSA-N Pyrrole Chemical compound C=1C=CNC=1 KAESVJOAVNADME-UHFFFAOYSA-N 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 239000002671 adjuvant Substances 0.000 description 2
- 125000004183 alkoxy alkyl group Chemical group 0.000 description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 125000003118 aryl group Chemical group 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 239000001913 cellulose Chemical class 0.000 description 2
- 229920002678 cellulose Chemical class 0.000 description 2
- 229910010293 ceramic material Inorganic materials 0.000 description 2
- 239000011247 coating layer Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000004643 cyanate ester Substances 0.000 description 2
- 238000007772 electroless plating Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000009477 glass transition Effects 0.000 description 2
- 229910052736 halogen Inorganic materials 0.000 description 2
- 150000002367 halogens Chemical group 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- AMWRITDGCCNYAT-UHFFFAOYSA-L hydroxy(oxo)manganese;manganese Chemical compound [Mn].O[Mn]=O.O[Mn]=O AMWRITDGCCNYAT-UHFFFAOYSA-L 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 229910044991 metal oxide Inorganic materials 0.000 description 2
- 150000004706 metal oxides Chemical class 0.000 description 2
- 229910052758 niobium Inorganic materials 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- 239000008188 pellet Substances 0.000 description 2
- ISWSIDIOOBJBQZ-UHFFFAOYSA-N phenol group Chemical class C1(=CC=CC=C1)O ISWSIDIOOBJBQZ-UHFFFAOYSA-N 0.000 description 2
- 125000000951 phenoxy group Chemical class [H]C1=C([H])C([H])=C(O*)C([H])=C1[H] 0.000 description 2
- 239000003880 polar aprotic solvent Substances 0.000 description 2
- 229920003192 poly(bis maleimide) Polymers 0.000 description 2
- 229920001721 polyimide Polymers 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 150000003460 sulfonic acids Chemical class 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229940117958 vinyl acetate Drugs 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 238000009736 wetting Methods 0.000 description 2
- MIOPJNTWMNEORI-GMSGAONNSA-N (S)-camphorsulfonic acid Chemical compound C1C[C@@]2(CS(O)(=O)=O)C(=O)C[C@@H]1C2(C)C MIOPJNTWMNEORI-GMSGAONNSA-N 0.000 description 1
- LBLYYCQCTBFVLH-UHFFFAOYSA-N 2-Methylbenzenesulfonic acid Chemical compound CC1=CC=CC=C1S(O)(=O)=O LBLYYCQCTBFVLH-UHFFFAOYSA-N 0.000 description 1
- WXHLLJAMBQLULT-UHFFFAOYSA-N 2-[[6-[4-(2-hydroxyethyl)piperazin-1-yl]-2-methylpyrimidin-4-yl]amino]-n-(2-methyl-6-sulfanylphenyl)-1,3-thiazole-5-carboxamide;hydrate Chemical compound O.C=1C(N2CCN(CCO)CC2)=NC(C)=NC=1NC(S1)=NC=C1C(=O)NC1=C(C)C=CC=C1S WXHLLJAMBQLULT-UHFFFAOYSA-N 0.000 description 1
- WBIQQQGBSDOWNP-UHFFFAOYSA-N 2-dodecylbenzenesulfonic acid Chemical compound CCCCCCCCCCCCC1=CC=CC=C1S(O)(=O)=O WBIQQQGBSDOWNP-UHFFFAOYSA-N 0.000 description 1
- YZTJKOLMWJNVFH-UHFFFAOYSA-N 2-sulfobenzene-1,3-dicarboxylic acid Chemical compound OC(=O)C1=CC=CC(C(O)=O)=C1S(O)(=O)=O YZTJKOLMWJNVFH-UHFFFAOYSA-N 0.000 description 1
- 125000002373 5 membered heterocyclic group Chemical group 0.000 description 1
- FLDCSPABIQBYKP-UHFFFAOYSA-N 5-chloro-1,2-dimethylbenzimidazole Chemical compound ClC1=CC=C2N(C)C(C)=NC2=C1 FLDCSPABIQBYKP-UHFFFAOYSA-N 0.000 description 1
- 125000004070 6 membered heterocyclic group Chemical group 0.000 description 1
- 125000003341 7 membered heterocyclic group Chemical group 0.000 description 1
- 239000001741 Ammonium adipate Substances 0.000 description 1
- FERIUCNNQQJTOY-UHFFFAOYSA-M Butyrate Chemical compound CCCC([O-])=O FERIUCNNQQJTOY-UHFFFAOYSA-M 0.000 description 1
- FERIUCNNQQJTOY-UHFFFAOYSA-N Butyric acid Natural products CCCC(O)=O FERIUCNNQQJTOY-UHFFFAOYSA-N 0.000 description 1
- 239000004971 Cross linker Substances 0.000 description 1
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 1
- VGGSQFUCUMXWEO-UHFFFAOYSA-N Ethene Chemical compound C=C VGGSQFUCUMXWEO-UHFFFAOYSA-N 0.000 description 1
- 239000005977 Ethylene Substances 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- 239000004962 Polyamide-imide Substances 0.000 description 1
- 239000005062 Polybutadiene Substances 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- 239000004734 Polyphenylene sulfide Substances 0.000 description 1
- 229920000292 Polyquinoline Polymers 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- XTXRWKRVRITETP-UHFFFAOYSA-N Vinyl acetate Chemical compound CC(=O)OC=C XTXRWKRVRITETP-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 125000006307 alkoxy benzyl group Chemical group 0.000 description 1
- 125000005036 alkoxyphenyl group Chemical group 0.000 description 1
- 125000006177 alkyl benzyl group Chemical group 0.000 description 1
- 125000005037 alkyl phenyl group Chemical group 0.000 description 1
- 125000002947 alkylene group Chemical group 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 235000019293 ammonium adipate Nutrition 0.000 description 1
- 239000010405 anode material Substances 0.000 description 1
- ILFFFKFZHRGICY-UHFFFAOYSA-N anthracene-1-sulfonic acid Chemical compound C1=CC=C2C=C3C(S(=O)(=O)O)=CC=CC3=CC2=C1 ILFFFKFZHRGICY-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- MIAUJDCQDVWHEV-UHFFFAOYSA-N benzene-1,2-disulfonic acid Chemical compound OS(=O)(=O)C1=CC=CC=C1S(O)(=O)=O MIAUJDCQDVWHEV-UHFFFAOYSA-N 0.000 description 1
- 229940092714 benzenesulfonic acid Drugs 0.000 description 1
- 150000008107 benzenesulfonic acids Chemical class 0.000 description 1
- 229910021393 carbon nanotube Inorganic materials 0.000 description 1
- 239000002041 carbon nanotube Substances 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 239000010406 cathode material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 150000001860 citric acid derivatives Chemical class 0.000 description 1
- 230000001010 compromised effect Effects 0.000 description 1
- 239000013068 control sample Substances 0.000 description 1
- 238000004132 cross linking Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000001627 detrimental effect Effects 0.000 description 1
- 150000001991 dicarboxylic acids Chemical class 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000002270 dispersing agent Substances 0.000 description 1
- 229940060296 dodecylbenzenesulfonic acid Drugs 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003822 epoxy resin Substances 0.000 description 1
- 238000009422 external insulation Methods 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 229920002313 fluoropolymer Polymers 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 229910052735 hafnium Inorganic materials 0.000 description 1
- 125000006277 halobenzyl group Chemical group 0.000 description 1
- 125000005059 halophenyl group Chemical group 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 229920001600 hydrophobic polymer Polymers 0.000 description 1
- 230000005661 hydrophobic surface Effects 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000011229 interlayer Substances 0.000 description 1
- 229910000464 lead oxide Inorganic materials 0.000 description 1
- IXHBTMCLRNMKHZ-LBPRGKRZSA-N levobunolol Chemical compound O=C1CCCC2=C1C=CC=C2OC[C@@H](O)CNC(C)(C)C IXHBTMCLRNMKHZ-LBPRGKRZSA-N 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- MIVBAHRSNUNMPP-UHFFFAOYSA-N manganese(2+);dinitrate Chemical compound [Mn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O MIVBAHRSNUNMPP-UHFFFAOYSA-N 0.000 description 1
- 239000002923 metal particle Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000012802 nanoclay Substances 0.000 description 1
- PSZYNBSKGUBXEH-UHFFFAOYSA-N naphthalene-1-sulfonic acid Chemical compound C1=CC=C2C(S(=O)(=O)O)=CC=CC2=C1 PSZYNBSKGUBXEH-UHFFFAOYSA-N 0.000 description 1
- BFRGSJVXBIWTCF-UHFFFAOYSA-N niobium monoxide Inorganic materials [Nb]=O BFRGSJVXBIWTCF-UHFFFAOYSA-N 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- YEXPOXQUZXUXJW-UHFFFAOYSA-N oxolead Chemical compound [Pb]=O YEXPOXQUZXUXJW-UHFFFAOYSA-N 0.000 description 1
- 235000021317 phosphate Nutrition 0.000 description 1
- 150000003013 phosphoric acid derivatives Chemical class 0.000 description 1
- 229920003023 plastic Polymers 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 229920000090 poly(aryl ether) Polymers 0.000 description 1
- 229920002492 poly(sulfone) Polymers 0.000 description 1
- 229920000058 polyacrylate Polymers 0.000 description 1
- 229920002239 polyacrylonitrile Polymers 0.000 description 1
- 229920002312 polyamide-imide Polymers 0.000 description 1
- 229920000412 polyarylene Polymers 0.000 description 1
- 229920002480 polybenzimidazole Polymers 0.000 description 1
- 229920002577 polybenzoxazole Polymers 0.000 description 1
- 229920002857 polybutadiene Polymers 0.000 description 1
- 229920000515 polycarbonate Polymers 0.000 description 1
- 239000004417 polycarbonate Substances 0.000 description 1
- 229920000647 polyepoxide Polymers 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920006393 polyether sulfone Polymers 0.000 description 1
- 229920001601 polyetherimide Polymers 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920001195 polyisoprene Polymers 0.000 description 1
- 229920000193 polymethacrylate Polymers 0.000 description 1
- 229920000069 polyphenylene sulfide Polymers 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 229920002689 polyvinyl acetate Polymers 0.000 description 1
- 239000011118 polyvinyl acetate Substances 0.000 description 1
- 229920000915 polyvinyl chloride Polymers 0.000 description 1
- 239000004800 polyvinyl chloride Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 229940100890 silver compound Drugs 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- 150000003871 sulfonates Chemical class 0.000 description 1
- 150000003464 sulfur compounds Chemical class 0.000 description 1
- 239000004094 surface-active agent Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000000930 thermomechanical effect Effects 0.000 description 1
- 229920001187 thermosetting polymer Polymers 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229920002554 vinyl polymer Polymers 0.000 description 1
- 239000011800 void material Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/04—Electrodes or formation of dielectric layers thereon
- H01G9/042—Electrodes or formation of dielectric layers thereon characterised by the material
- H01G9/0425—Electrodes or formation of dielectric layers thereon characterised by the material specially adapted for cathode
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/008—Terminals
- H01G9/012—Terminals specially adapted for solid capacitors
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/004—Details
- H01G9/08—Housing; Encapsulation
- H01G9/10—Sealing, e.g. of lead-in wires
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES, LIGHT-SENSITIVE OR TEMPERATURE-SENSITIVE DEVICES OF THE ELECTROLYTIC TYPE
- H01G9/00—Electrolytic capacitors, rectifiers, detectors, switching devices, light-sensitive or temperature-sensitive devices; Processes of their manufacture
- H01G9/15—Solid electrolytic capacitors
Definitions
- Patent Appl. No. 12/469,786 filed May 21 , 2009 now U.S. Pat. No. 8,310,816 issued Nov. 13, 2012 all of which are incorporated herein.
- the present invention is related to an improved method for preparing solid electrolytic capacitors with high temperature reliability.
- the present invention is related to an improved method of forming a solid electrolyte capacitor and an improved capacitor formed thereby. More specifically, the present invention is related to a capacitor with improved long term leakage performance at 200°C and above.
- valve metal serves as the anode.
- the anode body can be either a porous pellet, formed by pressing and sintering a high purity powder, or a foil which is etched to provide an increased anode surface area.
- An oxide of the valve metal is electrolytically formed to cover all surfaces of the anode and to serve as the dielectric of the capacitor.
- the solid cathode electrolyte is typically chosen from a very limited class of materials, to include manganese dioxide or electrically conductive organic materials such as 7,7,8,8 tetracyanoquinonedimethane (TCNQ) complex salt, or intrinsically conductive polymers, such as polyaniline, polypyrol, polythiophene and their derivatives.
- TCNQ 7,7,8,8 tetracyanoquinonedimethane
- TCNQ 7,7,8,8 tetracyanoquinonedimethane
- intrinsically conductive polymers such as polyaniline, polypyrol, polythiophene and their derivatives.
- the cathodic layer of a solid electrolyte capacitor typically consists of several layers which are external to the anode body.
- these layers typically include: a carbon layer; a cathode conductive layer which may be a layer containing a highly conductive metal, typically silver, bound in a polymer or resin matrix; and a conductive adhesive layer such as silver filled adhesive.
- the layers including the solid cathode electrolyte, conductive adhesive and layers there between are referred to collectively herein as the cathode layer which typically includes multiple layers designed to allow adhesion on one face to the dielectric and on the other face to the cathode lead.
- a highly conductive metal lead frame is used as a cathode lead for negative termination.
- the various layers connect the solid electrolyte to the outside circuit and also serves to protect the dielectric from thermo- mechanical damage that may occur during subsequent processing, board mounting, or customer use.
- the cathodic conductive layer which is typically a silver layer, serves to conduct current from the lead frame to the cathode and around the cathode to the sides not directly connected to the lead frame.
- the critical characteristics of this layer are high conductivity, adhesive strength to the carbon layer, wetting of the carbon layer, and acceptable mechanical properties.
- the oldest, and currently largest, user of high-temperature electronics is the downhole oil and gas industry (Analog Dialogue 46-04, April 2012). In this application, the operating temperature is a function of the underground depth of the well. Worldwide, the typical geothermal gradient is 25°C/km depth, but in some areas, it is greater. In the past, drilling operations have maxed out at
- Temperatures in these hostile wells can exceed 200°C, with pressures greater than 25 kpsi. Active cooling is not practical in this harsh environment, and passive cooling techniques are not effective when the heating is not confined to the electronics.
- the capacitor element is enclosed and hermetically sealed within a housing in the presence of a gaseous atmosphere that contains an inert gas. It is believed that the housing and inert gas atmosphere are capable of limiting the amount of oxygen and moisture supplied to the conductive polymer of the capacitor. In this manner, the solid electrolyte is less likely to undergo a reaction in high temperature environments, thus increasing the thermal stability of the capacitor assembly. Though capable of functioning at temperatures of about 215°C or 230°C this requires the capacitor to be in an environment which is void of moisture and air which is at least impractical if not impossible under typical working environments.
- Another object of the invention is to improve leakage stability of a capacitor at 200°C or above by replacing a silver particle filled layer with a plated metal layer.
- Another object of the invention is to improve leakage stability of a capacitor at 220°C or above by replacing a silver particle filled layer with a plated metal layer.
- Another object of the invention is to prepare solid electrolytic capacitors with an improved dielectric layer and a plated metal layer.
- Another object of the invention is to prepare solid electrolytic capacitors with an carbon layer containing a high glass transition temperature binder and a plated metal layer.
- Another object of the invention is to prepare solid electrolytic capacitors with a plated metal layer and an adhesive with high glass transition temperatures
- a particular advantage is provided by improving ESR stability on exposure to high temperature conditions.
- a solid electrolytic capacitor and a method for forming a solid electrolytic capacitor with high temperature leakage stability.
- the method includes: providing an anode; forming a dielectric on the anode; applying a cathode on the dielectric; applying a transition layer on the cathode wherein the transition layer comprises a blocking layer; plating a metal layer on the transition; and
- a solid electrolytic capacitor and a method for forming a solid electrolytic capacitor comprising: providing an anode; forming a dielectric on the anode; applying a cathode on the dielectric; applying a transition layer on said dielectric wherein said transition layer comprises a blocking layer; plating a metal layer on said transition layer; and electrically connecting a cathode termination to said cathode; wherein said solid electrolytic capacitor has a leakage shift of no more than 50% after 500 hrs at 200°C relative to the leakage after 500 hours at ambient temperature.
- Fig. 1 is a cross-sectional schematic view of a capacitor.
- Fig. 2 is a cross-sectional schematic view of an embodiment of the invention.
- Fig. 3 is a partial cross-sectional schematic view of a preferred transition layer of the present invention.
- Fig. 4 is a partial cross-sectional view of an embodiment of the present invention.
- Fig. 5 is a partial cross-sectional view of an embodiment of the present invention.
- Fig. 6 is a partial cross-sectional view of an embodiment of the present invention.
- Fig. 7 is a partial cross-sectional view of an embodiment of the present invention.
- Fig. 8 is a partial cross-sectional view of an embodiment of the present invention.
- FIG. 9 is a schematic illustration of an embodiment of the present invention.
- the present invention mitigates the deficiencies of the prior art by providing a capacitor with improved leakage current, particularly at high temperature, achieved by plated metal, and particularly plated nickel layers, and other optional layers.
- Fig. 1 illustrates a cross-sectional schematic view of a capacitor generally represented at 10.
- the capacitor comprises an anode, 1 1 , preferably comprising a valve metal as described further herein with an anode wire, 18, extending there from.
- a dielectric layer, 12 is provided on the surface of the anode, 1 1 .
- Coated on the surface of the dielectric layer, 12, is a cathode layer, 13.
- a carbon layer, 14, and plated metal layer, 16 provide electrical conductivity and provide a surface which is more readily adhered to the cathode terminal, 17, than is the cathode layer, 13.
- the layers between the cathode, 13, and plated layer, 16, are referred to collectively herein as the transition layer which typically includes multiple layers designed to allow adhesion on one face to a polymeric cathode and on the other face to the plated layer, 16.
- An adhesive layer, 21 secures the cathode lead to the plated metal layer.
- the anode wire, 18, is electrically connected to the anode terminal, 19, by a connector, 23.
- the anode terminal and connector may be integral to a lead frame.
- the entire element, except for the terminus of the terminals, is then preferably encased in a non-conducting material, 20, such as an epoxy resin to form a hermetic seal.
- the cathode comprises an improved transition layer. Included in the transition layer is a blocking layer, preferably selected from a hydrophobic layer and an insulative layer, which inhibits migration of metals and metal ions towards the dielectric. In a particularly preferred embodiment the blocking layer is between first and second carbon layers.
- a capacitor is illustrated schematically in Fig. 2 at 50.
- the anode, 1 1 ; dielectric, 12; cathode, 13; cathode termination, 17; anode wire, 18; anode termination, 19; and connector, 23, are as illustrated relative to Fig. 1 .
- Layer 16' is a plated layer as will be more fully described herein.
- the transition layer, 30, comprises a blocking layer as will be more fully described herein.
- the transition layer preferably encases the entire underlying structure.
- a second optional transition layer, 30', which preferably comprises a second blocking layer, is preferably disposed on at least a portion of the surface of the underlying monolith from which the anode wire, 18, extends.
- the second blocking layer may be the same as the blocking layer of the transition layer but extended beyond the area of the transition layer.
- the second blocking layer may be a layer which is different from the blocking layer of the transition layer.
- the non-conducting material, 20, can be a non-conducting polymer which is capable of withstanding the operating conditions of intended use or it may be an inert material such as a ceramic material, a plastic material or a metal as exemplified in US 2012/0106031 or combinations thereof.
- the function of blocking layer of the transition layer is to electrically connect the cathode, 13, to the plated metal layer, 16', while inhibiting metal and metal ions from migrating there through.
- One surface of the transition layer must be compatible with the cathode layer and the opposing surface must be compatible with the cathode termination or an adhesion layer attaching the transition layer to the cathode termination.
- the transition layer is typically a multiplicity of layers preferably starting with a carbon based layer, for adhesion directly to the cathode and subsequent adhesion to metal layers, followed by metal layers for adhesion to the carbon and cathode termination or adhesive layer with the blocking layer included therein.
- a preferred transition layer comprises a first carbon layer, 31 , which is formulated to adhere adequately to the cathode while still having adequate conductivity through the layer.
- a blocking layer, 32 is provided which inhibits the metal ion in the electroplating electrolyte from migrating into or through the blocking layer. It is preferred that no metal migrates through the blocking layer. In practice, minute amounts may migrate which is undesirable but acceptable. The blocking layer will be described more thoroughly herein.
- a second carbon layer, 33 is formulated to provide adhesion to the blocking layer and to the plated metal layer, 34.
- the plated metal layer, 34 is the eventual contact point within a circuit and is electrically connected to a cathode lead or to a circuit trace preferably by a
- the blocking layer is preferably between two carbon layers since this provides maximum adhesion.
- the blocking layer could be between a carbon layer and a metal layer or between the cathode and a carbon layer.
- the carbon layer may be a blocking layer.
- the blocking layer is preferably a hydrophobic layer or an electrically insulative layer.
- FIG. 4 An embodiment of the present invention is illustrated schematically in Fig. 4 at 50.
- the anode, 1 1 ; dielectric, 12; cathode, 13; cathode termination, 17; anode wire, 18; anode termination, 19; non-conducting material, 20; and connector, 23, are as illustrated relative to Fig. 1 .
- a metal filled layer, 36 preferably a silver filled layer, is on the transition layer, 30, and a plated metal layer, 34, is on the metal filled layer.
- FIG. 5 An embodiment of the invention is illustrated in Fig. 5 wherein a cross- sectional portion with the cathode, 13, plated metal layer, 34, and layers there between shown in isolation.
- Fig. 5 An embodiment of the invention is illustrated in Fig. 5 wherein a cross- sectional portion with the cathode, 13, plated metal layer, 34, and layers there between shown in isolation.
- a first carbon layer, 35 is in contact with the cathode and the layer is formulated to adhere adequately to the cathode while still having adequate conductivity through the layer.
- a blocking layer, 32 inhibits the metal ion in the electroplating electrolyte from migrating into or through the blocking layer.
- a second carbon layer, 33 is formulated to provide adhesion to the blocking layer and to the optional metal filled layer, 36.
- a plated metal layer, 34 is on the metal filled layer or in the absence thereof the second carbon layer. The plated metal layer, 34, is the eventual contact point within a circuit and is electrically connected to a cathode lead or to a circuit trace preferably by a conductive adhesive. In one embodiment there is no metal filled layer.
- FIG. 6 Another embodiment of the invention is illustrated in Fig. 6 wherein a cross-sectional portion with the cathode, 13, plated metal layer, 34, and layers there between shown in isolation.
- the blocking layer, 32 is between the cathode, 13, and the carbon layer, 35.
- This embodiment has the advantage of requiring one less layer.
- Fig. 7 A related embodiment is illustrated in Fig. 7 wherein the blocking layer, 32, is between the carbon layer, 35, and an optional metal filled layer, 36.
- FIG. 8 Another embodiment of the invention is illustrated in Fig. 8.
- a carbon layer, 35 is on the cathode, 13.
- Optional metal filled layers, 31 sandwich a blocking layer, 32, and a plated metal layer, 34, is on the outermost metal filled layer.
- the cathode layer is a conductive layer preferably comprising conductive polymer, such as polythiophene, polyaniline, polypyrrole or their derivatives;
- a particularly preferred conducting polymer is illustrated in Formula I:
- R 1 and R 2 of Formula 1 are chosen to prohibit polymerization at the ⁇ -site of the ring. It is most preferred that only a-site polymerization be allowed to proceed. Therefore, it is preferred that R 1 and R 2 are not hydrogen. More preferably, R 1 and R 2 are a-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 R 1 and R 2 taken together as -O-(CH 2 )2-O- is most preferred.
- X is S or N and most preferable X is S.
- R 1 and R 2 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 OR 3 ; or R 1 and R 2 , taken together, are linear d-Ce alkylene which is unsubstituted or substituted by C1-C6 alkyl, C1-C6 alkoxy, halogen, C3-C8 cycloalkyl, phenyl, benzyl, Ci-C 4 alkylphenyl, Ci- C 4 alkoxyphenyl, halophenyl, Ci-C 4 alkylbenzyl, Ci-C 4 alkoxybenzyl or halobenzyl, 5- , 6-, or 7- membered heterocyclic structure containing two oxygen elements.
- 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).
- PET 3,4-polyethylene dioxythiophene
- the polymer can be applied by any technique commonly employed in forming layers on a capacitor including dipping, spraying oxidizer dopant and monomer onto the pellet or foil, allowing the
- the polymer can also be applied by electrolytic deposition as well known in the art.
- the manganese dioxide layer is preferably obtained by immersing an anode element in an aqueous manganese nitrate solution.
- the manganese oxide is then formed by thermally decomposing the nitrate at a temperature of from 200 to 350°C in a dry or steam atmosphere.
- the anode may be treated multiple times to insure optimum coverage.
- 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 group, 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.
- Binders and cross-linkers can be also incorporated into the conductive polymer layer if desired.
- Suitable materials include polyvinyl acetate),
- polycarbonate polyvinyl butyrate
- polyacrylates polymethacrylates
- polystyrene polyacrylonitrile
- polyvinyl chloride polybutadiene
- polyisoprene polyethers
- polyesters polystyrene
- silicones polystyrene
- pyrrole/acrylate vinylacetate/acrylate and ethylene/vinyl acetate copolymers.
- the first carbon layer and second carbon layer which may be the same or different, each comprises a conductive composition comprising resin and conductive carbon particles.
- Each carbon layer may individually also comprise adjuvants such as crosslinking additives, surfactants and dispersing agents.
- the resin, conductive carbon particles and adjuvants are preferably dispersed in an organic solvent or water to form a coating solution.
- the solvent and resin for the first conductive carbon layer needs to have good wettability to the semi-conductive cathode surface.
- the blocking layer is most preferably less than two microns thick. Above about two microns the resistivity of the layer exceeds acceptable limits thereby defeating one of the purposes of the transition layers.
- the lower limit of thickness is set by the coating technique with a monolayer on the entire surface being the theoretical limit. This theoretical limit is difficult to reach with most coating
- the blocking layer is a poorly conducting layer its presence necessarily increases resistance between the cathode and cathode lead which is undesirable.
- the increased adhesion provides sufficient interlayer stability to mitigate the detrimental impact of the increased resistance.
- the hydrophobic coating preferably comprises hydrophobic polymers. Silicone and their copolymers, fluorinated polymers and their copolymers are mentioned as being particularly preferred.
- the hydrophobic layer may include fillers such as silica. Nanoclay and related materials modified with a hydrophobic coating is particularly suitable for demonstration of the invention.
- the hydrophobic coating is preferably a thermoset coating with high cross link density. The hydrophobic coating is chosen such that the plating electrolyte has very low wettability to the coated surface. In addition to providing low wettability the high cross link density prevents diffusion of plating electrolyte through this coating layer.
- a second carbon layer is preferably applied over the blocking layer. Since the blocking layer is designed to have low wettability to aqueous based systems, a water based carbon coating has very low adhesion to this surface. A solvent based carbon coating is preferred for this application. The solvent and resin of the carbon coating is chosen such that the coating can adequately wet the blocking layer which is typically a hydrophobic surface. In addition to wetting, the binder of the second carbon coating needs to have strong adhesion to the binder in the blocking layer as well as to the metal layer. The second carbon coating is preferably highly conductive to enable a faster rate of plating of the metal layer. In addition to the carbon particles such as graphite, carbon black, carbon nanotubes, graphene, metal particles can also be added to improve conductivity.
- the carbon particles such as graphite, carbon black, carbon nanotubes, graphene
- metal particles can also be added to improve conductivity.
- Preferred resins for the carbon layers are polymers of materials selected from the group phenolic, phenoxy, epoxy, acrylic, cellulose derivatives, aromatic cyanate esters, diallyl isophthalate, bismaleimide, polyimides, polyamide imides, polysulfones, polyphylenes, polyether sulfones, polyaryl ethers, polyphenylene sulfides, polyarylene ether ketones, polyether imides, polyquinoxalines,
- polyquinolines polybenzimidazoles, polybenzoxazoles, polybenzothiazoles, and silicones such as silicone polyester and silicone epoxy. More preferably the resin is selected from cellulose derivatives, acrylic, polyester, aromatic cyanate ester, epoxy, phenolic, diallyl isophthalate, phenoxy, polyimide and bismaleimide.
- the components of the cathode layer, including the transition layer, preferable has a high thermal decomposition temperature and preferably at least 350°C. More preferably the cathode layer, including the transition layer, preferable has a high thermal decomposition temperature and preferably at least 500°C.
- the plated metal layer may be applied to the second carbon coating.
- Plating can be done with various metallic systems. Nickel is a preferred metal system. Plating can be done either by electroplating or electroless plating.
- Electroplating is preferred due to the lower production cycle time.
- Conductive adhesive is typically used to adhesively attach the metal layer to the lead frame which acts as the cathode lead or to a circuit trace.
- FIG. 9 A preferred process for forming the capacitor is illustrated in Fig. 9.
- the anode is formed, 100, preferably from a valve metal as described further herein.
- the anode is a conductor preferably selected from a valve metal or a conductive metal oxide. More preferably the anode comprises a valve metal, a mixture, alloy or conductive oxide of a valve metal preferably selected from Al, W, Ta, Nb, Ti, Zr and Hf. Most preferably the anode comprises at least one material selected from the group consisting of Al, Ta, Nb and NbO. Conductive polymeric materials may be employed as an anode material. Particularly preferred conductive polymers include polypyrrole, polyaniline and polythiophene. Aluminum is typically employed as a foil while tantalum is typically prepared by pressing tantalum powder and sintering to form a compact. For convenience in handling, the valve metal is typically attached to a carrier thereby allowing large numbers of elements to be processed at the same time.
- the anode is preferably etched to increase the surface area particularly if the anode is a valve metal foil such as aluminum foil. Etching is preferably done by immersing the anode into at least one etching bath. Various etching baths are taught in the art and the method used for etching the anode is not limited herein.
- the anode wire is preferably attached to the anode, particularly when a compact is employed.
- the anode wire can be attached by welding or by embedding into the powder prior to pressing.
- a valve metal is a particularly suitable anode wire and in a preferred embodiment the anode and anode wire are the same material.
- a dielectric is formed, 101 , on the surface of the anode.
- 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 a metal anode due to the simplicity of formation and ease of use.
- the dielectric layer is preferably an oxide of the valve metal as further described herein. It is most desirable that the dielectric layer be an oxide of the anode.
- the dielectric is preferably formed by dipping the anode into an electrolyte solution and applying a positive voltage to the anode. Electrolytes for the oxide formation are not particularly limiting herein but exemplary materials can include ethylene glycol; polyethylene glycol dimethyl ether as described in U.S.
- a conductive layer is formed, 102, on the surface of the dielectric.
- the conductive layer acts as the cathode of the capacitor.
- the cathode is a conductor preferably comprising at least one conductive material selected from manganese dioxide and a conductive polymeric material.
- Particularly preferred conductive polymers include polypyrrole, polyaniline and polythiophene.
- Metals can be employed as a cathode material with valve metals being less preferred.
- a transition layer may be applied, 103, by spraying or dipping.
- a first carbon layer is applied, 104.
- a blocking layer is applied, 105, by spraying or dipping.
- a second carbon layer can be applied, 106, by spraying or dipping.
- a metal plated layer is formed, 107, preferably by electroplating or electroless plating.
- a particularly preferred metal plated layer is nickel.
- the capacitor may be a discrete capacitor or an embedded capacitor. If a discrete capacitor is to be formed, at 108, a conductive adhesive is added, 109, and the metal layer is adhered to a cathode lead, 1 10. The capacitor is finished, 1 1 1 , which may include incorporating anode and cathode terminals, external insulation, testing, packing and the like as known in the art.
- capacitors are to be employed in an embedded application or attached directly to a circuit trace the capacitors are finished, 1 12, which may include testing, packing and the like.
- the capacitor is illustrated herein as a discrete capacitor for convenience and this is a preferred embodiment.
- the anode wire and metal layer, of the transition layer may be in direct electrical contact with a circuit trace wherein elements of the circuit may constitute the cathode lead, anode lead or both.
- the capacitor may be embedded in a substrate or incorporated into an electrical component with additional functionality.
- a metal plated layer comprising nickel is particularly advantageous, with or without a blocking layer.
- the metal plated layer provides a capacitor with a particularly high reliability, particularly at temperatures above 200°C.
- a particularly preferred metal plating layer consists essentially of nickel. It is particularly preferred that the metal plated layer does not contain either sulfur or silver.
- a metal filled layer is defined herein as a layer comprising metal in an organic matrix.
- the present invention provides a solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 200°C. More preferably the solid electrolytic capacitor with a leakage current of no more than 0.05 CV after treatment for 500 hrs at a temperature of at least 200°C. Even more preferably, the solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 200°C. The present invention also provides a solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 220°C.
- Example 1 A series of identical tantalum anodes were prepared. The tantalum was anodized to form a dielectric on the tantalum anode in identical fashion. In one set of samples a manganese dioxide cathode was formed on the dielectric with first carbon layer comprising graphite dispersion in acrylic solution was applied. The capacitors with manganese dioxide cathodes were split into three groups. In a first control group a nickel plated layer was formed on the first carbon. In the second control group a silver layer was formed on the first carbon. In the inventive group a hydrophobic coating comprising silicone polymer solution was applied on the first carbon layer.
- a second carbon layer comprising a mixture of carbon black and graphite dispersion in a polyester binder was applied on the hydrophobic layer.
- a nickel plated layer was formed on the second carbon by electroplating. Both control and inventive samples were dried and electrical properties were measured at room temperature. The results are presented in Table 1 .
- Table 1 clearly illustrates the advantages of the present invention, particularly, with regards to a decrease in leakage current and ESR.
- a polymeric cathode was formed utilizing polyethylenedioxythiophene (PEDT) with carbon layers applied thereto respectively.
- the capacitors with PEDT cathodes were split into three groups.
- a nickel plated layer was formed on a first carbon layer comprising a carbon black and graphite dispersion in a polyester binder solution was applied.
- a carbon and silver layer was applied on a PEDT cathode.
- a hydrophobic coating comprising a silicone polymer solution was applied on the first carbon layer.
- a second carbon layer similar to the second carbon layer of Example 1 was applied on the hydrophobic layer.
- a nickel plated layer was formed on the second carbon by electroplating. Both control and inventive samples were dried and electrical properties were measured at room temperature. The results are provided in Table 2.
- Table 2 clearly illustrates the advantages offered by the present invention, particularly, with regards to leakage current.
- a polymeric cathode was formed utilizing polyethylenedioxythiophene (PEDT) polymers.
- the capacitors with PEDT cathodes were split into three groups. In the first control group a carbon layer was applied on PEDT followed with nickel plating. In a second control group a carbon and silver layer was applied on the PEDT cathode.
- a hydrophobic layer comprising silicone polymer solution was applied on the PEDT cathode. No carbon layer was applied in the inventive group. A nickel plated layer was formed on the hydrophobic layer by electroplating.
- Table 3 clearly illustrates the advantages offered by the present invention, particularly, with regards to leakage current and ESR.
- a series of tantalum anodes (100 microfarad, 16V) using two different sets of anodes was prepared.
- the tantalum was anodized to form a dielectric on the tantalum anode.
- a cathode layer was applied followed by a silver layer.
- Parts thus prepared were exposed to 200°C for several hours to determine the leakage stability at 200°C. After 500 hours at 200°C the comparative examples exhibited a leakage over about 4 CV with average leakage of about 16 CV with leakage of about 100 CV observed.
- Inventive Example 5 [0082] A series of tantalum anodes (100 microfarad, 16V) using two different sets of anodes was prepared. The tantalum was anodized to form a dielectric on the tantalum anode. A MnO2 cathode layer was applied. These parts were plated with Nickel. Parts thus prepared were exposed to 200°C for several hours to determine the leakage stability at 200°C. The leakage was essentially unchanged with treatment for up to 1000 hours.
- a series of tantalum anodes (220 microfarad, 10V) using two different sets of anodes was prepared.
- the tantalum was anodized to form a dielectric on the tantalum anode.
- a MnO2 cathode layer was applied.
- Case dimensions were 7.3mm (length), 4.3 mm (width), and 4.0 mm (height).
- Parts thus prepared were exposed to 220°C for 1000 hrs hours to determine the leakage stability at 220°C as illustrated in Fig. 8. The leakage was unchanged after 1000 hours of treatment which is a leakage shift of less then 50% and less than 20% whereas a control sample exhibited leakages in excess of 500 microamps for a significant portion of the samples tested which is a shift of in excess of 50%.
- CV is defined as the multiplicative product of capacitance and voltage, where capacitance is measured at 120Hz at rated voltage (V).
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Chemical & Material Sciences (AREA)
- Materials Engineering (AREA)
- Electroplating Methods And Accessories (AREA)
Abstract
A solid electrolytic capacitor and method for forming a solid electrolytic capacitor with high temperature leakage stability is described. The solid electrolytic capacitor has improved leakage current and is especially well suited for high temperature environments such as down-hole applications.
Description
SOLID ELECTROLYTIC CAPACITOR WITH HIGH TEMPERATURE LEAKAGE
STABILITY
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority to pending U.S. Provisional Application No. 61/718,847 filed 10/26/2012 which is incorporated herein by reference. The present application is also a continuation-in-part of pending U.S. Pat. Appl. No. 13/863,451 filed April 16, 2013 which is a divisional application of patented U.S. Pat. Appl. No. 12/972,917 filed December 20, 201 1 now US. Pat. No. 8,305,165 issued August 6, 2013 which is, in turn, a continuation-in-part of patented U.S.
Patent Appl. No. 12/469,786 filed May 21 , 2009 now U.S. Pat. No. 8,310,816 issued Nov. 13, 2012 all of which are incorporated herein.
BACKGROUND
[0002] The present invention is related to an improved method for preparing solid electrolytic capacitors with high temperature reliability.
[0003] The present invention is related to an improved method of forming a solid electrolyte capacitor and an improved capacitor formed thereby. More specifically, the present invention is related to a capacitor with improved long term leakage performance at 200°C and above.
[0004] The construction and manufacture of solid electrolyte capacitors is well documented. In the construction of a solid electrolytic capacitor a valve metal serves as the anode. The anode body can be either a porous pellet, formed by pressing and sintering a high purity powder, or a foil which is etched to provide an increased anode surface area. An oxide of the valve metal is electrolytically formed to cover all surfaces of the anode and to serve as the dielectric of the capacitor. The solid
cathode electrolyte is typically chosen from a very limited class of materials, to include manganese dioxide or electrically conductive organic materials such as 7,7,8,8 tetracyanoquinonedimethane (TCNQ) complex salt, or intrinsically conductive polymers, such as polyaniline, polypyrol, polythiophene and their derivatives. The solid cathode electrolyte is applied so that it covers the dielectric surfaces and is in direct intimate contact with the dielectric. In addition to the solid electrolyte, the cathodic layer of a solid electrolyte capacitor typically consists of several layers which are external to the anode body. In the case of surface mount constructions these layers typically include: a carbon layer; a cathode conductive layer which may be a layer containing a highly conductive metal, typically silver, bound in a polymer or resin matrix; and a conductive adhesive layer such as silver filled adhesive. The layers including the solid cathode electrolyte, conductive adhesive and layers there between are referred to collectively herein as the cathode layer which typically includes multiple layers designed to allow adhesion on one face to the dielectric and on the other face to the cathode lead. A highly conductive metal lead frame is used as a cathode lead for negative termination. The various layers connect the solid electrolyte to the outside circuit and also serves to protect the dielectric from thermo- mechanical damage that may occur during subsequent processing, board mounting, or customer use.
[0005] The cathodic conductive layer, which is typically a silver layer, serves to conduct current from the lead frame to the cathode and around the cathode to the sides not directly connected to the lead frame. The critical characteristics of this layer are high conductivity, adhesive strength to the carbon layer, wetting of the carbon layer, and acceptable mechanical properties.
[0006] The oldest, and currently largest, user of high-temperature electronics (>150°C) is the downhole oil and gas industry (Analog Dialogue 46-04, April 2012). In this application, the operating temperature is a function of the underground depth of the well. Worldwide, the typical geothermal gradient is 25°C/km depth, but in some areas, it is greater. In the past, drilling operations have maxed out at
temperatures of 150°C to 175°C, but declining reserves of easily accessible natural resources coupled with advances in technology have motivated the industry to drill deeper, as well as in regions of the world with a higher geothermal gradient.
Temperatures in these hostile wells can exceed 200°C, with pressures greater than 25 kpsi. Active cooling is not practical in this harsh environment, and passive cooling techniques are not effective when the heating is not confined to the electronics.
Besides the oil and gas industries, other applications, such as avionics, are emerging for high-temperature electronics.
[0007] U.S. Pat. No. 7,233, 483, which is incorporated herein by reference, teaches a method for improving high temperature (85°C) performance of capacitors wherein the cathode comprises a silver layer with the silver layer further comprising silver and/or sulfur compounds. The performance is inadequate for higher
temperature applications.
[0008] US 2012/0106031 , which is incorporated herein by reference, claims an improved capacitor assembly for use in high voltage and high temperature
environments wherein the capacitor element is enclosed and hermetically sealed within a housing in the presence of a gaseous atmosphere that contains an inert gas. It is believed that the housing and inert gas atmosphere are capable of limiting the amount of oxygen and moisture supplied to the conductive polymer of the capacitor. In this manner, the solid electrolyte is less likely to undergo a reaction in high
temperature environments, thus increasing the thermal stability of the capacitor assembly. Though capable of functioning at temperatures of about 215°C or 230°C this requires the capacitor to be in an environment which is void of moisture and air which is at least impractical if not impossible under typical working environments.
[0009] The prior art methods do not offer a solution for leakage degradation at high temperature such as 200°C or above typically seen in an oil rig environment.
[0010] Thus there is a need for a solid electrolytic capacitor, and a method of making a solid electrolytic capacitor, which has good reliability when exposed to a temperature of 200°C or above for 1000 hrs or the duration of intended application. A particular need is for a capacitor with a stable leakage and ESR at 200°C or above.
SUMMARY
[0011] It is an object of the invention to provide an improved solid electrolytic capacitor.
[0012] It is an object of the invention to provide an improved method of preparing a solid electrolytic capacitor cathode.
[0013] Another object of the invention is to improve leakage stability of a capacitor at 200°C or above by replacing a silver particle filled layer with a plated metal layer.
[0014] Another object of the invention is to improve leakage stability of a capacitor at 220°C or above by replacing a silver particle filled layer with a plated metal layer.
[0015] Another object of the invention is to prepare solid electrolytic capacitors with an improved dielectric layer and a plated metal layer.
[0016] Another object of the invention is to prepare solid electrolytic capacitors with an carbon layer containing a high glass transition temperature binder and a plated metal layer.
[0017] Another object of the invention is to prepare solid electrolytic capacitors with a plated metal layer and an adhesive with high glass transition temperatures
[0018] A particular advantage is provided by improving ESR stability on exposure to high temperature conditions.
[0019] These and other advantages, as will be realized, are provided in a solid electrolytic capacitor and a method for forming a solid electrolytic capacitor with high temperature leakage stability. The method includes: providing an anode; forming a dielectric on the anode; applying a cathode on the dielectric; applying a transition layer on the cathode wherein the transition layer comprises a blocking layer; plating a metal layer on the transition; and
electrically connecting a cathode termination to the cathode wherein the solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 200°C.
[0020] Yet another embodiment is provided in a solid electrolytic capacitor and a method for forming a solid electrolytic capacitor comprising: providing an anode; forming a dielectric on the anode; applying a cathode on the dielectric; applying a transition layer on said dielectric wherein said transition layer comprises a blocking layer; plating a metal layer on said transition layer; and electrically connecting a cathode termination to said cathode; wherein said solid electrolytic capacitor has a leakage shift of no more than 50% after 500 hrs at 200°C relative to the leakage after 500 hours at ambient temperature.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Fig. 1 is a cross-sectional schematic view of a capacitor.
[0022] Fig. 2 is a cross-sectional schematic view of an embodiment of the invention.
[0023] Fig. 3 is a partial cross-sectional schematic view of a preferred transition layer of the present invention.
[0024] Fig. 4 is a partial cross-sectional view of an embodiment of the present invention.
[0025] Fig. 5 is a partial cross-sectional view of an embodiment of the present invention.
[0026] Fig. 6 is a partial cross-sectional view of an embodiment of the present invention.
[0027] Fig. 7 is a partial cross-sectional view of an embodiment of the present invention.
[0028] Fig. 8 is a partial cross-sectional view of an embodiment of the present invention.
[0029] Fig. 9 is a schematic illustration of an embodiment of the present invention.
DETAILED DESCRIPTION
[0030] It has now been surprisingly found that, significantly improved leakage stability at 200°C and above can be obtained by replacing the polymeric silver coating layer with a plated metal layer or a metal deposited layer.
[0031] The present invention mitigates the deficiencies of the prior art by providing a capacitor with improved leakage current, particularly at high temperature,
achieved by plated metal, and particularly plated nickel layers, and other optional layers.
[0032] The present invention will be described with reference to the various figures which illustrate, without limiting, the invention. Throughout the description similar elements will be numbered accordingly.
[0033] Fig. 1 illustrates a cross-sectional schematic view of a capacitor generally represented at 10. The capacitor comprises an anode, 1 1 , preferably comprising a valve metal as described further herein with an anode wire, 18, extending there from. A dielectric layer, 12, is provided on the surface of the anode, 1 1 . Coated on the surface of the dielectric layer, 12, is a cathode layer, 13. A carbon layer, 14, and plated metal layer, 16, provide electrical conductivity and provide a surface which is more readily adhered to the cathode terminal, 17, than is the cathode layer, 13. The layers between the cathode, 13, and plated layer, 16, are referred to collectively herein as the transition layer which typically includes multiple layers designed to allow adhesion on one face to a polymeric cathode and on the other face to the plated layer, 16. An adhesive layer, 21 , secures the cathode lead to the plated metal layer. The anode wire, 18, is electrically connected to the anode terminal, 19, by a connector, 23. The anode terminal and connector may be integral to a lead frame. The entire element, except for the terminus of the terminals, is then preferably encased in a non-conducting material, 20, such as an epoxy resin to form a hermetic seal.
[0034] In one embodiment the cathode comprises an improved transition layer. Included in the transition layer is a blocking layer, preferably selected from a hydrophobic layer and an insulative layer, which inhibits migration of metals and
metal ions towards the dielectric. In a particularly preferred embodiment the blocking layer is between first and second carbon layers.
[0035] A capacitor is illustrated schematically in Fig. 2 at 50. In Fig. 2 the anode, 1 1 ; dielectric, 12; cathode, 13; cathode termination, 17; anode wire, 18; anode termination, 19; and connector, 23, are as illustrated relative to Fig. 1 . Layer 16' is a plated layer as will be more fully described herein. The transition layer, 30, comprises a blocking layer as will be more fully described herein. The transition layer preferably encases the entire underlying structure. A second optional transition layer, 30', which preferably comprises a second blocking layer, is preferably disposed on at least a portion of the surface of the underlying monolith from which the anode wire, 18, extends. The second blocking layer may be the same as the blocking layer of the transition layer but extended beyond the area of the transition layer. Alternatively, the second blocking layer may be a layer which is different from the blocking layer of the transition layer. The non-conducting material, 20, can be a non-conducting polymer which is capable of withstanding the operating conditions of intended use or it may be an inert material such as a ceramic material, a plastic material or a metal as exemplified in US 2012/0106031 or combinations thereof.
[0036] The function of blocking layer of the transition layer is to electrically connect the cathode, 13, to the plated metal layer, 16', while inhibiting metal and metal ions from migrating there through. One surface of the transition layer must be compatible with the cathode layer and the opposing surface must be compatible with the cathode termination or an adhesion layer attaching the transition layer to the cathode termination. To accomplish these tasks the transition layer is typically a multiplicity of layers preferably starting with a carbon based layer, for adhesion directly to the cathode and subsequent adhesion to metal layers, followed by metal
layers for adhesion to the carbon and cathode termination or adhesive layer with the blocking layer included therein.
[0037] An embodiment of the transition layer is illustrated in Fig. 3 wherein a cross-sectional portion of the transition layer, 30, and plated metal layer, 34, is shown in isolation. A preferred transition layer comprises a first carbon layer, 31 , which is formulated to adhere adequately to the cathode while still having adequate conductivity through the layer. A blocking layer, 32, is provided which inhibits the metal ion in the electroplating electrolyte from migrating into or through the blocking layer. It is preferred that no metal migrates through the blocking layer. In practice, minute amounts may migrate which is undesirable but acceptable. The blocking layer will be described more thoroughly herein. A second carbon layer, 33, is formulated to provide adhesion to the blocking layer and to the plated metal layer, 34. The plated metal layer, 34, is the eventual contact point within a circuit and is electrically connected to a cathode lead or to a circuit trace preferably by a
conductive adhesive. The blocking layer is preferably between two carbon layers since this provides maximum adhesion. The blocking layer could be between a carbon layer and a metal layer or between the cathode and a carbon layer. In an alternative embodiment the carbon layer may be a blocking layer. The blocking layer is preferably a hydrophobic layer or an electrically insulative layer.
[0038] An embodiment of the present invention is illustrated schematically in Fig. 4 at 50. In Fig. 4 the anode, 1 1 ; dielectric, 12; cathode, 13; cathode termination, 17; anode wire, 18; anode termination, 19; non-conducting material, 20; and connector, 23, are as illustrated relative to Fig. 1 . A metal filled layer, 36, preferably a silver filled layer, is on the transition layer, 30, and a plated metal layer, 34, is on the metal filled layer.
[0039] An embodiment of the invention is illustrated in Fig. 5 wherein a cross- sectional portion with the cathode, 13, plated metal layer, 34, and layers there between shown in isolation. In the embodiment of Fig. 5 a first carbon layer, 35, is in contact with the cathode and the layer is formulated to adhere adequately to the cathode while still having adequate conductivity through the layer. A blocking layer, 32, inhibits the metal ion in the electroplating electrolyte from migrating into or through the blocking layer. A second carbon layer, 33, is formulated to provide adhesion to the blocking layer and to the optional metal filled layer, 36. A plated metal layer, 34, is on the metal filled layer or in the absence thereof the second carbon layer. The plated metal layer, 34, is the eventual contact point within a circuit and is electrically connected to a cathode lead or to a circuit trace preferably by a conductive adhesive. In one embodiment there is no metal filled layer.
[0040] Another embodiment of the invention is illustrated in Fig. 6 wherein a cross-sectional portion with the cathode, 13, plated metal layer, 34, and layers there between shown in isolation. In Fig. 6 the blocking layer, 32, is between the cathode, 13, and the carbon layer, 35. This embodiment has the advantage of requiring one less layer. A related embodiment is illustrated in Fig. 7 wherein the blocking layer, 32, is between the carbon layer, 35, and an optional metal filled layer, 36.
[0041] Another embodiment of the invention is illustrated in Fig. 8. In Fig. 8, a carbon layer, 35, is on the cathode, 13. Optional metal filled layers, 31 , sandwich a blocking layer, 32, and a plated metal layer, 34, is on the outermost metal filled layer.
[0042] The cathode layer is a conductive layer preferably comprising conductive polymer, such as polythiophene, polyaniline, polypyrrole or their derivatives;
manganese dioxide, lead oxide or combinations thereof.
FORMULA 1
[0044] R1 and R2 of Formula 1 are chosen to prohibit polymerization at the β-site of the ring. It is most preferred that only a-site polymerization be allowed to proceed. Therefore, it is preferred that R1 and R2 are not hydrogen. More preferably, R1 and R2 are a-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.
[0045] In Formula 1 , X is S or N and most preferable X is S.
[0046] 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 d-Ce alkylene which is unsubstituted or substituted by C1-C6 alkyl, C1-C6 alkoxy, halogen, C3-C8 cycloalkyl, phenyl, benzyl, Ci-C4 alkylphenyl, Ci- C4 alkoxyphenyl, halophenyl, Ci-C4 alkylbenzyl, Ci-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.
[0047] 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 polymer can be applied by any technique commonly employed in forming layers on a capacitor including dipping, spraying oxidizer dopant and monomer onto the pellet or foil, allowing the
polymerization to occur for a set time, and ending the polymerization with a wash. The polymer can also be applied by electrolytic deposition as well known in the art.
[0048] The manganese dioxide layer is preferably obtained by immersing an anode element in an aqueous manganese nitrate solution. The manganese oxide is then formed by thermally decomposing the nitrate at a temperature of from 200 to 350°C in a dry or steam atmosphere. The anode may be treated multiple times to insure optimum coverage.
[0049] 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 group, 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.
[0050] Binders and cross-linkers can be also incorporated into the conductive polymer layer if desired. Suitable materials include polyvinyl acetate),
polycarbonate, polyvinyl butyrate), polyacrylates, polymethacrylates, polystyrene, polyacrylonitrile, polyvinyl chloride), polybutadiene, polyisoprene, polyethers,
polyesters, silicones, and pyrrole/acrylate, vinylacetate/acrylate and ethylene/vinyl acetate copolymers.
[0051] The first carbon layer and second carbon layer, which may be the same or different, each comprises a conductive composition comprising resin and conductive carbon particles. Each carbon layer may individually also comprise adjuvants such as crosslinking additives, surfactants and dispersing agents. The resin, conductive carbon particles and adjuvants are preferably dispersed in an organic solvent or water to form a coating solution. The solvent and resin for the first conductive carbon layer needs to have good wettability to the semi-conductive cathode surface.
[0052] The blocking layer is most preferably less than two microns thick. Above about two microns the resistivity of the layer exceeds acceptable limits thereby defeating one of the purposes of the transition layers. The lower limit of thickness is set by the coating technique with a monolayer on the entire surface being the theoretical limit. This theoretical limit is difficult to reach with most coating
techniques due to the presence of surface vacancies wherein the blocking properties are compromised. Since the blocking layer is a poorly conducting layer its presence necessarily increases resistance between the cathode and cathode lead which is undesirable. Surprisingly, the increased adhesion provides sufficient interlayer stability to mitigate the detrimental impact of the increased resistance.
[0053] The hydrophobic coating preferably comprises hydrophobic polymers. Silicone and their copolymers, fluorinated polymers and their copolymers are mentioned as being particularly preferred. The hydrophobic layer may include fillers such as silica. Nanoclay and related materials modified with a hydrophobic coating is particularly suitable for demonstration of the invention. The hydrophobic coating is preferably a thermoset coating with high cross link density. The hydrophobic coating
is chosen such that the plating electrolyte has very low wettability to the coated surface. In addition to providing low wettability the high cross link density prevents diffusion of plating electrolyte through this coating layer.
[0054] A second carbon layer is preferably applied over the blocking layer. Since the blocking layer is designed to have low wettability to aqueous based systems, a water based carbon coating has very low adhesion to this surface. A solvent based carbon coating is preferred for this application. The solvent and resin of the carbon coating is chosen such that the coating can adequately wet the blocking layer which is typically a hydrophobic surface. In addition to wetting, the binder of the second carbon coating needs to have strong adhesion to the binder in the blocking layer as well as to the metal layer. The second carbon coating is preferably highly conductive to enable a faster rate of plating of the metal layer. In addition to the carbon particles such as graphite, carbon black, carbon nanotubes, graphene, metal particles can also be added to improve conductivity.
[0055] Preferred resins for the carbon layers are polymers of materials selected from the group phenolic, phenoxy, epoxy, acrylic, cellulose derivatives, aromatic cyanate esters, diallyl isophthalate, bismaleimide, polyimides, polyamide imides, polysulfones, polyphylenes, polyether sulfones, polyaryl ethers, polyphenylene sulfides, polyarylene ether ketones, polyether imides, polyquinoxalines,
polyquinolines, polybenzimidazoles, polybenzoxazoles, polybenzothiazoles, and silicones such as silicone polyester and silicone epoxy. More preferably the resin is selected from cellulose derivatives, acrylic, polyester, aromatic cyanate ester, epoxy, phenolic, diallyl isophthalate, phenoxy, polyimide and bismaleimide.
[0056] The components of the cathode layer, including the transition layer, preferable has a high thermal decomposition temperature and preferably at least
350°C. More preferably the cathode layer, including the transition layer, preferable has a high thermal decomposition temperature and preferably at least 500°C.
[0057] The plated metal layer may be applied to the second carbon coating. Plating can be done with various metallic systems. Nickel is a preferred metal system. Plating can be done either by electroplating or electroless plating.
Electroplating is preferred due to the lower production cycle time. Conductive adhesive is typically used to adhesively attach the metal layer to the lead frame which acts as the cathode lead or to a circuit trace.
[0058] A preferred process for forming the capacitor is illustrated in Fig. 9.
[0059] In Fig. 9, the anode is formed, 100, preferably from a valve metal as described further herein.
[0060] The anode is a conductor preferably selected from a valve metal or a conductive metal oxide. More preferably the anode comprises a valve metal, a mixture, alloy or conductive oxide of a valve metal preferably selected from Al, W, Ta, Nb, Ti, Zr and Hf. Most preferably the anode comprises at least one material selected from the group consisting of Al, Ta, Nb and NbO. Conductive polymeric materials may be employed as an anode material. Particularly preferred conductive polymers include polypyrrole, polyaniline and polythiophene. Aluminum is typically employed as a foil while tantalum is typically prepared by pressing tantalum powder and sintering to form a compact. For convenience in handling, the valve metal is typically attached to a carrier thereby allowing large numbers of elements to be processed at the same time.
[0061] The anode is preferably etched to increase the surface area particularly if the anode is a valve metal foil such as aluminum foil. Etching is preferably done by
immersing the anode into at least one etching bath. Various etching baths are taught in the art and the method used for etching the anode is not limited herein.
[0062] The anode wire is preferably attached to the anode, particularly when a compact is employed. The anode wire can be attached by welding or by embedding into the powder prior to pressing. A valve metal is a particularly suitable anode wire and in a preferred embodiment the anode and anode wire are the same material.
[0063] A dielectric is formed, 101 , on the surface of the anode. 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 a metal anode due to the simplicity of formation and ease of use. The dielectric layer is preferably an oxide of the valve metal as further described herein. It is most desirable that the dielectric layer be an oxide of the anode. The dielectric is preferably formed by dipping the anode into an electrolyte solution and applying a positive voltage to the anode. Electrolytes for the oxide formation are not particularly limiting herein but exemplary materials can include ethylene glycol; polyethylene glycol dimethyl ether as described in U.S. Pat. Nos. 5,716,51 1 ; alkanolamines and phosphoric acid, as described in U.S. Pat. Nos. 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. Patent 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 to the dielectric layer.
[0064] A conductive layer is formed, 102, on the surface of the dielectric. The conductive layer acts as the cathode of the capacitor. The cathode is a conductor preferably comprising at least one conductive material selected from manganese dioxide and a conductive polymeric material. Particularly preferred conductive polymers include polypyrrole, polyaniline and polythiophene. Metals can be employed as a cathode material with valve metals being less preferred.
[0065] After conductive cathode layer formation, 102, a transition layer may be applied, 103, by spraying or dipping. In one embodiment a first carbon layer is applied, 104. A blocking layer is applied, 105, by spraying or dipping. After blocking layer formation a second carbon layer can be applied, 106, by spraying or dipping.
[0066] A metal plated layer is formed, 107, preferably by electroplating or electroless plating. A particularly preferred metal plated layer is nickel.
[0067] The capacitor may be a discrete capacitor or an embedded capacitor. If a discrete capacitor is to be formed, at 108, a conductive adhesive is added, 109, and the metal layer is adhered to a cathode lead, 1 10. The capacitor is finished, 1 1 1 , which may include incorporating anode and cathode terminals, external insulation, testing, packing and the like as known in the art.
[0068] If the capacitors are to be employed in an embedded application or attached directly to a circuit trace the capacitors are finished, 1 12, which may include testing, packing and the like.
[0069] The capacitor is illustrated herein as a discrete capacitor for convenience and this is a preferred embodiment. In another preferred embodiment the anode wire and metal layer, of the transition layer, may be in direct electrical contact with a circuit trace wherein elements of the circuit may constitute the cathode lead, anode
lead or both. In another preferred embodiment the capacitor may be embedded in a substrate or incorporated into an electrical component with additional functionality.
[0070] A metal plated layer comprising nickel is particularly advantageous, with or without a blocking layer. The metal plated layer provides a capacitor with a particularly high reliability, particularly at temperatures above 200°C. A particularly preferred metal plating layer consists essentially of nickel. It is particularly preferred that the metal plated layer does not contain either sulfur or silver.
[0071] A metal filled layer is defined herein as a layer comprising metal in an organic matrix.
[0072] The present invention provides a solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 200°C. More preferably the solid electrolytic capacitor with a leakage current of no more than 0.05 CV after treatment for 500 hrs at a temperature of at least 200°C. Even more preferably, the solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 200°C. The present invention also provides a solid electrolytic capacitor with a leakage current of no more than 0.10 CV after treatment for 500 hrs at a temperature of at least 220°C. More preferably the solid electrolytic capacitor with a leakage current of no more than 0.05 CV after treatment for 500 hrs at a temperature of at least 220°C. Even more preferably, the solid electrolytic capacitor with a leakage current of no more than 0.01 CV after treatment for 500 hrs at a temperature of at least 220°C.
EXAMPLES
Example 1 :
[0073] A series of identical tantalum anodes were prepared. The tantalum was anodized to form a dielectric on the tantalum anode in identical fashion. In one set of samples a manganese dioxide cathode was formed on the dielectric with first carbon layer comprising graphite dispersion in acrylic solution was applied. The capacitors with manganese dioxide cathodes were split into three groups. In a first control group a nickel plated layer was formed on the first carbon. In the second control group a silver layer was formed on the first carbon. In the inventive group a hydrophobic coating comprising silicone polymer solution was applied on the first carbon layer. A second carbon layer comprising a mixture of carbon black and graphite dispersion in a polyester binder was applied on the hydrophobic layer. A nickel plated layer was formed on the second carbon by electroplating. Both control and inventive samples were dried and electrical properties were measured at room temperature. The results are presented in Table 1 .
TABLE 1 :
[0074] Table 1 clearly illustrates the advantages of the present invention, particularly, with regards to a decrease in leakage current and ESR.
Example 2:
[0075] On an identical set of samples a polymeric cathode was formed utilizing polyethylenedioxythiophene (PEDT) with carbon layers applied thereto respectively. The capacitors with PEDT cathodes were split into three groups. In a control group
a nickel plated layer was formed on a first carbon layer comprising a carbon black and graphite dispersion in a polyester binder solution was applied. In the second control group, a carbon and silver layer was applied on a PEDT cathode. In the inventive group a hydrophobic coating comprising a silicone polymer solution was applied on the first carbon layer. A second carbon layer similar to the second carbon layer of Example 1 was applied on the hydrophobic layer. A nickel plated layer was formed on the second carbon by electroplating. Both control and inventive samples were dried and electrical properties were measured at room temperature. The results are provided in Table 2.
TABLE 2:
[0076] Table 2 clearly illustrates the advantages offered by the present invention, particularly, with regards to leakage current.
Example 3:
[0077] On an identical set of samples a polymeric cathode was formed utilizing polyethylenedioxythiophene (PEDT) polymers. The capacitors with PEDT cathodes were split into three groups. In the first control group a carbon layer was applied on PEDT followed with nickel plating. In a second control group a carbon and silver layer was applied on the PEDT cathode. In the inventive group, a hydrophobic layer comprising silicone polymer solution was applied on the PEDT cathode. No carbon
layer was applied in the inventive group. A nickel plated layer was formed on the hydrophobic layer by electroplating.
[0078] Both control and inventive samples were dried and electrical properties were measured at room temperature. The results are provided in Table 3.
TABLE 3:
[0079] Table 3 clearly illustrates the advantages offered by the present invention, particularly, with regards to leakage current and ESR.
[0080] The invention has been described with particular emphasis on the preferred embodiments. One of skill in the art would realize additional embodiments, alterations, and advances which, though not enumerated, are within the invention as set forth more specifically in the claims appended hereto.
Comparative Example 4:
[0081] A series of tantalum anodes (100 microfarad, 16V) using two different sets of anodes was prepared. The tantalum was anodized to form a dielectric on the tantalum anode. A cathode layer was applied followed by a silver layer. Parts thus prepared were exposed to 200°C for several hours to determine the leakage stability at 200°C. After 500 hours at 200°C the comparative examples exhibited a leakage over about 4 CV with average leakage of about 16 CV with leakage of about 100 CV observed.
Inventive Example 5:
[0082] A series of tantalum anodes (100 microfarad, 16V) using two different sets of anodes was prepared. The tantalum was anodized to form a dielectric on the tantalum anode. A MnO2 cathode layer was applied. These parts were plated with Nickel. Parts thus prepared were exposed to 200°C for several hours to determine the leakage stability at 200°C. The leakage was essentially unchanged with treatment for up to 1000 hours.
Inventive Example 6:
[0083] A series of tantalum anodes (220 microfarad, 10V) using two different sets of anodes was prepared. The tantalum was anodized to form a dielectric on the tantalum anode. A MnO2 cathode layer was applied. These parts were plated with nickel, assembled and encapsulated. Case dimensions were 7.3mm (length), 4.3 mm (width), and 4.0 mm (height). Parts thus prepared were exposed to 220°C for 1000 hrs hours to determine the leakage stability at 220°C as illustrated in Fig. 8. The leakage was unchanged after 1000 hours of treatment which is a leakage shift of less then 50% and less than 20% whereas a control sample exhibited leakages in excess of 500 microamps for a significant portion of the samples tested which is a shift of in excess of 50%.
[0084] Test Methods: CV is defined as the multiplicative product of capacitance and voltage, where capacitance is measured at 120Hz at rated voltage (V).
Claims
1 . A method for forming a solid electrolytic capacitor with high temperature leakage
stability comprising:
providing an anode;
forming a dielectric on said anode;
applying a cathode on said dielectric;
applying a transition layer on said cathode wherein said transition layer comprises a blocking layer;
plating a metal layer on said transition; and
electrically connecting a cathode termination to said cathode
wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 200°C.
2. The method for forming a solid electrolytic capacitor of claim 1 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 200°C.
3. The method for forming a solid electrolytic capacitor of claim 2 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 200°C.
4. The method for forming a solid electrolytic capacitor of claim 1 wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature of at least 220°C.
5. The method for forming a solid electrolytic capacitor of claim 4 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at temperature of at least 220°C.
6. The method for forming a solid electrolytic capacitor of claim 5 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at temperature of at least 220°C.
7. The method for forming a solid electrolytic capacitor of claim 6 wherein said metal layer does not contain silver or sulfur.
8. The method for forming a solid electrolytic capacitor of claim 1 wherein said plating a metal layer comprises plating a layer comprising nickel.
9. The method for forming a solid electrolytic capacitor of claim 8 wherein said plating comprises plating a layer consisting essentially of nickel.
10. The method for forming a solid electrolytic capacitor of claim 1 wherein said cathode comprises MnO2.
1 1 . The method for forming a solid electrolytic capacitor of claim 1 wherein said cathode layer has a thermal decomposition temperature of greater than 350°C.
12. The method for forming a solid electrolytic capacitor of claim 1 1 wherein said thermal decomposition temperature is greater than 500°C.
13. The method for forming a solid electrolytic capacitor of claim 1 wherein the capacitor is encapsulated.
14. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a material selected from polymer, metal and ceramic.
15. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a hermetic seal.
16. The method for forming a solid electrolytic capacitor of claim 13 wherein said capacitor is encapsulated in a material which does not form a hermetic seal.
17. The method for forming a solid electrolytic capacitor of claim 1 wherein said blocking layer has a thickness of no more than 2 microns.
18. The method for forming a solid electrolytic capacitor of claim 1 wherein said transition layer does not include a metal filled layer.
19. A method for forming a solid electrolytic capacitor comprising: providing an anode;
forming a dielectric on said anode;
applying a cathode on said dielectric;
applying a transition layer on said dielectric wherein said transition layer comprises a blocking layer;
plating a metal layer on said transition layer; and
electrically connecting a cathode termination to said cathode;
wherein said solid electrolytic capacitor has a leakage shift of no more than 50% after 500 hrs at 200°C relative to the leakage after 500 hours at ambient temperature.
20. The method for forming a solid electrolytic capacitor of claim 19 wherein said solid electrolytic capacitor has a leakage shift of no more than 50% after 500 hrs at 220°C relative to the leakage after 500 hours at ambient temperature.
21 . The method for forming a solid electrolytic capacitor of claim 19 wherein the median leakage shift at 200°C for 500 hrs is less than 20% relative to the leakage after 500 hours at ambient temperature.
22. The method for forming a solid electrolytic capacitor of claim 19 wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at a temperature of at least 200°C.
23. The method for forming a solid electrolytic capacitor of claim 19 wherein said capacitor has a leakage of no more than 0.10 CV after 500 hrs at temperature greater than 220°C.
24. The method for forming a solid electrolytic capacitor of claim 19 wherein said metal layer does not contain silver or sulfur.
25. The method for forming a solid electrolytic capacitor of claim 19 wherein said plating a metal layer comprises plating a layer comprising nickel.
26. The method for forming a solid electrolytic capacitor of claim 25 wherein said plating a metal layer comprises plating a layer consisting essentially of nickel.
27. The method for forming a solid electrolytic capacitor of claim 19 wherein said cathode is MnO2.
28. The method for forming a solid electrolytic capacitor of claim 19 wherein said cathode layer has a thermal decomposition temperature of greater than 350°C.
29. The method for forming a solid electrolytic capacitor of claim 28 wherein said thermal decomposition temperature is greater than 500°C.
30. The method for forming a solid electrolytic capacitor of claim 19 wherein said capacitor is encapsulated.
31 . The method for forming a solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a material selected from polymer, metal and ceramic.
32. The method for forming a solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a hermetic seal.
33. The method for forming a solid electrolytic capacitor of claim 30 wherein said capacitor is encapsulated in a material which does not form a hermetic seal.
34. The method for forming a solid electrolytic capacitor of claim 19 wherein said blocking layer has a thickness of less than 2 microns.
35. A solid electrolytic capacitor comprising:
an anode with an anode lead in electrical contact with said anode;
a dielectric on said anode;
a cathode on said dielectric with a cathode lead in electrical contact with said cathode wherein said cathode comprises a conductive layer, a blocking layer and a plated layer comprising nickel; and
wherein said solid electrolytic capacitor has a leakage of 0.10 CV after 500 hrs at temperature of at least 200°C.
36. The solid electrolytic capacitor of claim 35 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at
temperature of at least 200°C.
37. The solid electrolytic capacitor of claim 36 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at
temperature of at least 200°C.
38. The solid electrolytic capacitor of claim 35 wherein said solid electrolytic capacitor has a leakage of no more than 0.10 CV after 500 hrs at
temperature of at least 220°C.
39. The solid electrolytic capacitor of claim 38 wherein said solid electrolytic capacitor has a leakage of no more than 0.05 CV after 500 hrs at
temperature of at least 220°C.
40. The solid electrolytic capacitor of claim 39 wherein said solid electrolytic capacitor has a leakage of no more than 0.01 CV after 500 hrs at
temperature of at least 220°C.
41 . The solid electrolytic capacitor of claim 35 wherein said plated layer does not contain silver or sulfur.
42. The solid electrolytic capacitor of claim 41 wherein said plated layer consisting essentially of nickel.
43. The solid electrolytic capacitor of claim 35 wherein said cathode is MnO2.
44. The solid electrolytic capacitor of claim 35 wherein said cathode layer has a thermal decomposition temperature of greater than 350°C.
45. The solid electrolytic capacitor of claim 44 wherein said cathode layer has a thermal decomposition temperature of greater than 500°C.
46. The solid electrolytic capacitor of claim 35 wherein the capacitor is
encapsulated.
47. The solid electrolytic capacitor of claim 46 wherein said capacitor is
encapsulated in a material selected from polymer, metal and ceramic.
48. The solid electrolytic capacitor of claim 46 wherein said capacitor is
encapsulated in a hermetic seal.
49. The solid electrolytic capacitor of claim 46 wherein said capacitor is
encapsulated in a material which does not form a hermetic seal.
50. The solid electrolytic capacitor of claim 35 wherein said blocking layer has a thickness of less than 2 microns.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP13848241.9A EP2912673A4 (en) | 2012-10-26 | 2013-10-25 | Solid electrolytic capacitor with high temperature leakage stability |
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201261718847P | 2012-10-26 | 2012-10-26 | |
US61/718,847 | 2012-10-26 | ||
US13/863,451 | 2013-04-16 | ||
US13/863,451 US8896985B2 (en) | 2010-12-20 | 2013-04-16 | Solid electrolytic capacitors with improved reliability |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2014066817A1 true WO2014066817A1 (en) | 2014-05-01 |
Family
ID=50545342
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2013/066913 WO2014066817A1 (en) | 2012-10-26 | 2013-10-25 | Solid electrolytic capacitor with high temperature leakage stability |
Country Status (2)
Country | Link |
---|---|
EP (1) | EP2912673A4 (en) |
WO (1) | WO2014066817A1 (en) |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4104704A (en) * | 1974-12-23 | 1978-08-01 | P.R. Mallory & Co. Inc. | Capacitor including an electroplated layer thereover |
US4203194A (en) * | 1978-07-17 | 1980-05-20 | Sprague Electric Company | Batch method for making solid-electrolyte capacitors |
US4571664A (en) * | 1984-11-09 | 1986-02-18 | Mepco/Electra, Inc. | Solid electrolyte capacitor for surface mounting |
US5142452A (en) * | 1990-08-07 | 1992-08-25 | Nec Corporation | Chip-type solid electrolytic capacitors |
US20040212951A1 (en) * | 1999-05-24 | 2004-10-28 | Showa Denko K.K. | Solid electrolytic capacitor and method for producing the same |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8310816B2 (en) * | 2009-05-21 | 2012-11-13 | Kemet Electronics Corporation | Solid electrolytic capacitors with improved reliability |
-
2013
- 2013-10-25 WO PCT/US2013/066913 patent/WO2014066817A1/en active Application Filing
- 2013-10-25 EP EP13848241.9A patent/EP2912673A4/en not_active Withdrawn
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4104704A (en) * | 1974-12-23 | 1978-08-01 | P.R. Mallory & Co. Inc. | Capacitor including an electroplated layer thereover |
US4203194A (en) * | 1978-07-17 | 1980-05-20 | Sprague Electric Company | Batch method for making solid-electrolyte capacitors |
US4571664A (en) * | 1984-11-09 | 1986-02-18 | Mepco/Electra, Inc. | Solid electrolyte capacitor for surface mounting |
US5142452A (en) * | 1990-08-07 | 1992-08-25 | Nec Corporation | Chip-type solid electrolytic capacitors |
US20040212951A1 (en) * | 1999-05-24 | 2004-10-28 | Showa Denko K.K. | Solid electrolytic capacitor and method for producing the same |
Non-Patent Citations (1)
Title |
---|
See also references of EP2912673A4 * |
Also Published As
Publication number | Publication date |
---|---|
EP2912673A4 (en) | 2016-05-18 |
EP2912673A1 (en) | 2015-09-02 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US8310816B2 (en) | Solid electrolytic capacitors with improved reliability | |
US8896985B2 (en) | Solid electrolytic capacitors with improved reliability | |
US7348194B2 (en) | Electrode compositions containing carbon nanotubes for solid electrolyte capacitors | |
US6154358A (en) | Solid electrolytic capacitor using a conducting polymer | |
US8083920B2 (en) | Method for manufacturing solid electrolytic capacitor | |
JP6472388B2 (en) | Low ESR capacitor | |
KR101049431B1 (en) | Capacitor and method of manufacturing the capacitor | |
US8840685B2 (en) | Solid electrolytical capacitors with improved ESR stability | |
JP2012119427A (en) | Solid electrolytic capacitor and method of manufacturing the same | |
US10403443B2 (en) | Solid electrolytic capacitor with high temperature leakage stability | |
US20100246096A1 (en) | Use of conjugated oligomer as additive for forming conductive polymers | |
EP2912673A1 (en) | Solid electrolytic capacitor with high temperature leakage stability | |
KR100753612B1 (en) | Solid Electrolyte Capacitor and Method for Producing the Same | |
JP2853376B2 (en) | Manufacturing method of capacitor | |
JP2005089517A (en) | Conductive polymer and solid electrolytic capacitor using the same |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 13848241 Country of ref document: EP Kind code of ref document: A1 |
|
DPE1 | Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101) | ||
NENP | Non-entry into the national phase |
Ref country code: DE |
|
REEP | Request for entry into the european phase |
Ref document number: 2013848241 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2013848241 Country of ref document: EP |