JP2008293999A - Battery - Google Patents
Battery Download PDFInfo
- Publication number
- JP2008293999A JP2008293999A JP2008204310A JP2008204310A JP2008293999A JP 2008293999 A JP2008293999 A JP 2008293999A JP 2008204310 A JP2008204310 A JP 2008204310A JP 2008204310 A JP2008204310 A JP 2008204310A JP 2008293999 A JP2008293999 A JP 2008293999A
- Authority
- JP
- Japan
- Prior art keywords
- battery
- tab
- sealed
- negative electrode
- sealing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000007789 sealing Methods 0.000 claims abstract description 70
- 229910052751 metal Inorganic materials 0.000 claims abstract description 36
- 239000002184 metal Substances 0.000 claims abstract description 36
- 229920005989 resin Polymers 0.000 claims abstract description 23
- 239000011347 resin Substances 0.000 claims abstract description 23
- 239000010408 film Substances 0.000 claims description 27
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 26
- 239000002245 particle Substances 0.000 claims description 14
- 239000010409 thin film Substances 0.000 claims description 14
- 229910002804 graphite Inorganic materials 0.000 claims description 10
- 239000010439 graphite Substances 0.000 claims description 10
- 239000007770 graphite material Substances 0.000 claims description 10
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- 239000003575 carbonaceous material Substances 0.000 description 14
- 239000004020 conductor Substances 0.000 description 14
- -1 polypropylene Polymers 0.000 description 14
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 13
- 229920000642 polymer Polymers 0.000 description 12
- 239000002904 solvent Substances 0.000 description 12
- 239000007773 negative electrode material Substances 0.000 description 11
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 11
- 239000000243 solution Substances 0.000 description 11
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 10
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- 229910052782 aluminium Inorganic materials 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 8
- 238000005452 bending Methods 0.000 description 8
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- 239000000463 material Substances 0.000 description 8
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- 230000000052 comparative effect Effects 0.000 description 7
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- 229910052799 carbon Inorganic materials 0.000 description 6
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- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 4
- 229910013870 LiPF 6 Inorganic materials 0.000 description 4
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
- 239000002033 PVDF binder Substances 0.000 description 4
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- 229920002981 polyvinylidene fluoride Polymers 0.000 description 4
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 3
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- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- 239000004721 Polyphenylene oxide Substances 0.000 description 3
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- 238000002844 melting Methods 0.000 description 3
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- 239000002002 slurry Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 229910001220 stainless steel Inorganic materials 0.000 description 3
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 2
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 2
- IAYPIBMASNFSPL-UHFFFAOYSA-N Ethylene oxide Chemical compound C1CO1 IAYPIBMASNFSPL-UHFFFAOYSA-N 0.000 description 2
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 2
- 229910012851 LiCoO 2 Inorganic materials 0.000 description 2
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 description 2
- 238000001069 Raman spectroscopy Methods 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 229910021383 artificial graphite Inorganic materials 0.000 description 2
- 230000004888 barrier function Effects 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000006229 carbon black Substances 0.000 description 2
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- 238000000605 extraction Methods 0.000 description 2
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- 238000010304 firing Methods 0.000 description 2
- 229910052731 fluorine Inorganic materials 0.000 description 2
- 239000011737 fluorine Substances 0.000 description 2
- GAEKPEKOJKCEMS-UHFFFAOYSA-N gamma-valerolactone Chemical compound CC1CCC(=O)O1 GAEKPEKOJKCEMS-UHFFFAOYSA-N 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- PQXKHYXIUOZZFA-UHFFFAOYSA-M lithium fluoride Chemical compound [Li+].[F-] PQXKHYXIUOZZFA-UHFFFAOYSA-M 0.000 description 2
- MCVFFRWZNYZUIJ-UHFFFAOYSA-M lithium;trifluoromethanesulfonate Chemical compound [Li+].[O-]S(=O)(=O)C(F)(F)F MCVFFRWZNYZUIJ-UHFFFAOYSA-M 0.000 description 2
- TZIHFWKZFHZASV-UHFFFAOYSA-N methyl formate Chemical compound COC=O TZIHFWKZFHZASV-UHFFFAOYSA-N 0.000 description 2
- 239000004570 mortar (masonry) Substances 0.000 description 2
- 150000002894 organic compounds Chemical class 0.000 description 2
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- 238000006116 polymerization reaction Methods 0.000 description 2
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- 238000012719 thermal polymerization Methods 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- 229910052719 titanium Inorganic materials 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- LZDKZFUFMNSQCJ-UHFFFAOYSA-N 1,2-diethoxyethane Chemical compound CCOCCOCC LZDKZFUFMNSQCJ-UHFFFAOYSA-N 0.000 description 1
- RYHBNJHYFVUHQT-UHFFFAOYSA-N 1,4-Dioxane Chemical compound C1COCCO1 RYHBNJHYFVUHQT-UHFFFAOYSA-N 0.000 description 1
- QTWJRLJHJPIABL-UHFFFAOYSA-N 2-methylphenol;3-methylphenol;4-methylphenol Chemical compound CC1=CC=C(O)C=C1.CC1=CC=CC(O)=C1.CC1=CC=CC=C1O QTWJRLJHJPIABL-UHFFFAOYSA-N 0.000 description 1
- JWUJQDFVADABEY-UHFFFAOYSA-N 2-methyltetrahydrofuran Chemical compound CC1CCCO1 JWUJQDFVADABEY-UHFFFAOYSA-N 0.000 description 1
- PPDFQRAASCRJAH-UHFFFAOYSA-N 2-methylthiolane 1,1-dioxide Chemical compound CC1CCCS1(=O)=O PPDFQRAASCRJAH-UHFFFAOYSA-N 0.000 description 1
- 125000003903 2-propenyl group Chemical group [H]C([*])([H])C([H])=C([H])[H] 0.000 description 1
- JZVUAOCDNFNSGQ-UHFFFAOYSA-N 7-methoxy-2-phenyl-1h-quinolin-4-one Chemical compound N=1C2=CC(OC)=CC=C2C(O)=CC=1C1=CC=CC=C1 JZVUAOCDNFNSGQ-UHFFFAOYSA-N 0.000 description 1
- 238000004438 BET method Methods 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- 229910000733 Li alloy Inorganic materials 0.000 description 1
- 229910012722 Li3N-LiI-LiOH Inorganic materials 0.000 description 1
- 229910012716 Li3N-LiI—LiOH Inorganic materials 0.000 description 1
- 229910012734 Li3N—LiI—LiOH Inorganic materials 0.000 description 1
- 229910012850 Li3PO4Li4SiO4 Inorganic materials 0.000 description 1
- 229910010238 LiAlCl 4 Inorganic materials 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910015645 LiMn Inorganic materials 0.000 description 1
- 229910015643 LiMn 2 O 4 Inorganic materials 0.000 description 1
- 229910013290 LiNiO 2 Inorganic materials 0.000 description 1
- 229910012513 LiSbF 6 Inorganic materials 0.000 description 1
- 229910012573 LiSiO Inorganic materials 0.000 description 1
- 229910012346 LiSiO4-LiI-LiOH Inorganic materials 0.000 description 1
- 229910012345 LiSiO4-LiI—LiOH Inorganic materials 0.000 description 1
- 229910012348 LiSiO4—LiI—LiOH Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 1
- VKCLPVFDVVKEKU-UHFFFAOYSA-N S=[P] Chemical class S=[P] VKCLPVFDVVKEKU-UHFFFAOYSA-N 0.000 description 1
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 1
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
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- 229910052786 argon Inorganic materials 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
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- 238000010280 constant potential charging Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
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- 239000011889 copper foil Substances 0.000 description 1
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- 230000001351 cycling effect Effects 0.000 description 1
- 238000002050 diffraction method Methods 0.000 description 1
- GYZLOYUZLJXAJU-UHFFFAOYSA-N diglycidyl ether Chemical class C1OC1COCC1CO1 GYZLOYUZLJXAJU-UHFFFAOYSA-N 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- VUPKGFBOKBGHFZ-UHFFFAOYSA-N dipropyl carbonate Chemical compound CCCOC(=O)OCCC VUPKGFBOKBGHFZ-UHFFFAOYSA-N 0.000 description 1
- 238000010494 dissociation reaction Methods 0.000 description 1
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- 238000004090 dissolution Methods 0.000 description 1
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- KLKFAASOGCDTDT-UHFFFAOYSA-N ethoxymethoxyethane Chemical compound CCOCOCC KLKFAASOGCDTDT-UHFFFAOYSA-N 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
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- 125000000524 functional group Chemical group 0.000 description 1
- 239000007849 furan resin Substances 0.000 description 1
- 150000002240 furans Chemical class 0.000 description 1
- 150000004820 halides Chemical class 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 239000003999 initiator Substances 0.000 description 1
- 229920000554 ionomer Polymers 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
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- 239000011244 liquid electrolyte Substances 0.000 description 1
- 239000001989 lithium alloy Substances 0.000 description 1
- HSZCZNFXUDYRKD-UHFFFAOYSA-M lithium iodide Inorganic materials [Li+].[I-] HSZCZNFXUDYRKD-UHFFFAOYSA-M 0.000 description 1
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical compound [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 description 1
- 239000002931 mesocarbon microbead Substances 0.000 description 1
- 239000011302 mesophase pitch Substances 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
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- 125000005394 methallyl group Chemical group 0.000 description 1
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- 239000011241 protective layer Substances 0.000 description 1
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- 238000007086 side reaction Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- VKJKOXNPYVUXNC-UHFFFAOYSA-K trilithium;trioxido(oxo)-$l^{5}-arsane Chemical compound [Li+].[Li+].[Li+].[O-][As]([O-])([O-])=O VKJKOXNPYVUXNC-UHFFFAOYSA-K 0.000 description 1
- 125000000391 vinyl group Chemical group [H]C([*])=C([H])[H] 0.000 description 1
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Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
Landscapes
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
- Sealing Battery Cases Or Jackets (AREA)
Abstract
Description
本発明は、ラミネート外装体によって封止された電池に関する。更に詳しくは、本発明は、改良された構造の封口部を有する電池に関し、その構造により電池内部への水分の進入を防ぐことができ、その結果電池の信頼性を向上させることができる。 The present invention relates to a battery sealed with a laminate outer package. More specifically, the present invention relates to a battery having a sealing portion having an improved structure, and the structure can prevent moisture from entering the battery, thereby improving the reliability of the battery.
電池にはさまざまな種類があるが、その中でもリチウムイオン電池の普及により、携帯機器の電源としての電池は小型化、軽量化が飛躍的に進んだ。しかしながら、携帯機器のさらなる小型化、薄型化の要求は強く、それに伴って電池の小型化、薄型化が強く望まれている。
従来、電池の外装体には、金属板を用途に応じて、円筒型、角型、コイン型等に成形した電池缶と蓋が用いられてきた。この場合、電池缶と蓋がそれぞれ、正極、負極の端子の機能を兼ね備えている。また、電池の気密性は、電池缶と蓋を、樹脂製のパッキンを挾みかしめ方法、又は両者間をガラスのような封止材を用いてハーメチックシールする方法、レーザーで溶接する方法等によって密閉することにより保たれている。
There are various types of batteries. Among them, with the widespread use of lithium-ion batteries, the battery as a power source for portable devices has been dramatically reduced in size and weight. However, there is a strong demand for further downsizing and thinning of portable devices, and accordingly, downsizing and thinning of batteries are strongly desired.
Conventionally, battery cans and lids in which a metal plate is formed into a cylindrical shape, a square shape, a coin shape, or the like have been used for battery outer bodies depending on the application. In this case, the battery can and the lid each have the functions of a positive electrode terminal and a negative electrode terminal. In addition, the airtightness of the battery is determined by a method in which the battery can and the lid are squeezed with a resin packing, or a hermetic seal between the two using a sealing material such as glass, a method of welding with a laser, or the like. It is kept by sealing.
しかしながら、このような電池缶を用いた電池では、軽量化、薄型化に限界があり、特に薄型化に関しては、厚みの限界は通常４ｍｍ程度である。そこで、さらなる軽量化、薄型化をめざして、電池缶を使用しない電池として、特開昭６０−１００３６２号公報、特開昭６０−６５４４２号公報等に、金属箔と熱融着性樹脂フィルムからなるラミネート外装体に、正極、負極及びイオン伝導体からなる電池素子が封入された電池が提案されている。また、特開平１０−２１４６０６号公報には、ラミネート外装体の封口部が、電池素子の表面で接着されてなる薄型電池が提案されている。
ラミネート外装体は、基本的にはガス遮断性、特に水分の進入を防ための金属薄膜と、熱融着性を付与するための熱融着性樹脂フィルム層からなる。樹脂フィルムはガス遮断性、特に水蒸気に対する遮断効果が十分ではなく、このため金属薄膜は必要不可欠なものである。 The laminate outer package basically comprises a metal thin film for preventing gas from entering, particularly moisture, and a heat-fusible resin film layer for imparting heat-fusibility. The resin film does not have a sufficient gas barrier property, particularly a water barrier effect, and therefore a metal thin film is indispensable.
しかしながら、特開昭６０−１００３６２号公報及び特開昭６０-６５４４２号公報では、封止部を断面方向からみると、電池内部と外気の間には金属箔層が存在せず、熱融着性の樹脂層のみで外気から遮断されている。そのため、気密性を上げるために、封止部の幅を広くする必要があった。特に電池から電気を取り出すための金属製のタブの取り出し部分は、気密性を下げる要因になりやすい。 However, in Japanese Patent Application Laid-Open No. 60-100322 and Japanese Patent Application Laid-Open No. 60-65442, when the sealing portion is viewed from the cross-sectional direction, there is no metal foil layer between the inside of the battery and the outside air. It is shielded from the outside air only by the functional resin layer. Therefore, it is necessary to increase the width of the sealing portion in order to increase the airtightness. In particular, the extraction portion of the metal tab for extracting electricity from the battery tends to be a factor of lowering airtightness.
また、特開平１０-２１４６０６号公報には、ラミネート外装体の封口部を電池素子の表面に設けることにより（図６参照）、封止部の幅を広くすることが提案されている。しかし、封止部全辺を電池素子の表面に設けることは不可能であり、電池素子の表面以外の辺についてはある程度封止部の幅を広くする必要があった。 Japanese Patent Application Laid-Open No. 10-214606 proposes to widen the sealing portion by providing a sealing portion of the laminate outer package on the surface of the battery element (see FIG. 6). However, it is impossible to provide the entire side of the sealing portion on the surface of the battery element, and it is necessary to increase the width of the sealing portion to some extent for the sides other than the surface of the battery element.
上述のように、封口部の信頼性を上げるために、封口部の幅を広くした場合、電池のサイズが大きくなってしまうといった問題点を有していた。つまり、気密信頼性を上げるために、封止部の幅は十分広くしたいが、エネルギー密度を向上させるためには封止部の幅をできる限り狭くしたいといった矛盾が生じることになる。また封止部の幅を広くし、その封止部を電池の裏面（又は表面）に折り返すことによって、電池の投影面積を小さくすることも考えられるが、それでは電池の厚みが大きくなり、薄型電池としての特徴が薄れてしまう。 As described above, when the width of the sealing portion is widened in order to increase the reliability of the sealing portion, there is a problem that the size of the battery becomes large. That is, there is a contradiction that the width of the sealing portion is desired to be sufficiently wide in order to improve hermetic reliability, but the width of the sealing portion is desired to be as narrow as possible in order to improve the energy density. It is also conceivable to reduce the projected area of the battery by widening the width of the sealing part and folding the sealing part back to the back surface (or front surface) of the battery. However, this increases the thickness of the battery and reduces the thickness of the battery. As the feature will fade.
また、タブの引き出し部分の気密信頼性の向上のために、タブに金属の多孔体を用いることが考えられるが、多孔体は金属箔に比べ脆く、かつタブと封口部の境界には応力がかかりやすいため、タブ切れを起こすといった問題があった。
本発明の目的は、電池のサイズ、又は厚みを大きくすることなく気密性が保たれたラミネート外装体により封止された電池を提供することにある。
In order to improve the airtight reliability of the tab lead-out portion, it is conceivable to use a metal porous body for the tab. However, the porous body is more fragile than the metal foil, and stress is applied to the boundary between the tab and the sealing portion. Because it was easy to start, there was a problem of causing tab breaks.
An object of the present invention is to provide a battery sealed with a laminate outer package that maintains hermeticity without increasing the size or thickness of the battery.
かくして本発明によれば、少なくとも金属薄膜と熱融着性樹脂フィルムからなるラミネート外装体に封入された正極、負極及びイオン伝導体からなる電池において、少なくとも封止部の１辺が少なくとも一回折り曲げた状態で熱融着されており、負極が黒鉛粒子の表面に非晶質炭素層を有する黒鉛材料を含むことを特徴とする電池が提供される。 Thus, according to the present invention, in a battery comprising a positive electrode, a negative electrode and an ionic conductor encapsulated in a laminate outer package comprising at least a metal thin film and a heat-fusible resin film, at least one side of the sealing portion is bent at least once. There is provided a battery characterized in that the negative electrode contains a graphite material having an amorphous carbon layer on the surface of the graphite particles.
本発明によれば、封止部を折り曲げることによって電池の面積を大きくすることなく、封口部の幅を広くすることが可能となり、また密閉性が向上するため、気密信頼性を改善できる。その結果、電池の信頼性、特にサイクル特性を向上させることができる。
折り曲げた封止部を、タブ導出部に適用することにより、密閉性の向上効果は大きい。更に、少なくとも一回折り曲げられて封止されてなる辺に直交する辺の封止を、ラミネート外装体の裏と表を熱融着することによって行えば、２回折り曲げる部分がなくなりより信頼性があがる。
According to the present invention, it is possible to increase the width of the sealing portion without increasing the battery area by bending the sealing portion, and the airtight reliability can be improved because the sealing performance is improved. As a result, the reliability of the battery, particularly the cycle characteristics can be improved.
By applying the bent sealing portion to the tab lead-out portion, the effect of improving the sealing performance is great. Furthermore, if the side perpendicular to the side that is bent and sealed once is sealed by heat-sealing the back and front of the laminate outer package, the portion that is bent twice is eliminated and more reliable. Get nervous.
更に、投影面積で考えた場合、封止部の面積を小さくすることが可能で、またラミネートパックの素材は、電池素子に比べ十分に薄いため、折り曲げることによって電池の総厚みより厚くなることがないため、厚みを厚くすることなく、投影面積あたりの容量を大きくすることが可能である。
更に、負極材料にPCGを用いることにより、電解液の分解を抑えることができるので、気密信頼性があがる。またゲル状の電解質の場合には、それと負極活物質の固−固界面が壊れるのを防ぐことができるため、電池の信頼性、特にサイクル特性を向上させることができる。
また、本発明における封止方法と表面非晶質黒鉛（PCG）を負極に用いた場合には、PCを用いても十分な気密信頼性が確保できるため、従来低温特性が弱いとされていたゲル状の電解質を使用した電池においても優れた低温特性が得られる。
Furthermore, when considering the projected area, it is possible to reduce the area of the sealing portion, and the material of the laminate pack is sufficiently thin compared to the battery element, so that it may become thicker than the total thickness of the battery by folding. Therefore, the capacity per projected area can be increased without increasing the thickness.
Furthermore, by using PCG as the negative electrode material, it is possible to suppress the decomposition of the electrolytic solution, thereby improving airtight reliability. In the case of a gel electrolyte, the solid-solid interface between the electrolyte and the negative electrode active material can be prevented from being broken, so that the battery reliability, particularly the cycle characteristics, can be improved.
In addition, when the sealing method and surface amorphous graphite (PCG) in the present invention are used for the negative electrode, sufficient airtight reliability can be ensured even if PC is used, so that low temperature characteristics have been conventionally weak. Excellent low temperature characteristics can be obtained even in a battery using a gel electrolyte.
本発明の電池は、少なくとも金属薄膜と熱融着性樹脂フィルムからなるラミネート外装体に電池素子が封入されてなる電池において、少なくとも封止部の１辺が少なくとも一回折り曲げた状態で熱融着された構成を有することを特徴とする。
このような構造により、電池のサイズを大きくすることなく、封止部の実質的な幅を広げることが可能となり、気密信頼性を向上させることが可能となる。
The battery of the present invention is a battery in which a battery element is encapsulated in a laminate outer package made of at least a metal thin film and a heat-fusible resin film, and is heat-sealed with at least one side of the sealing portion bent at least once. It has the structure comprised.
With such a structure, the substantial width of the sealing portion can be expanded without increasing the size of the battery, and the airtight reliability can be improved.
ラミネート外装体は、少なくとも金属薄膜と熱融着性樹脂フィルムからなるが、その構造は、金属薄膜と熱溶融性樹脂フィルムとの２層、熱溶融性樹脂フィルムで金属薄膜を挟んだ３層、更にそれ以上の積層構造を有していてもよい。更に必要に応じてポリエステルフィルム等からなる金属薄膜の保護層を設けてもよい。この内、ラミネート外装体の最外層には熱溶融性樹脂フィルムが位置していることが好ましい。最外層に熱溶融性樹脂フィルムが位置することにより、熱融着による封止を容易に行うことができる。 The laminate outer package is composed of at least a metal thin film and a heat-fusible resin film, and its structure is composed of two layers of a metal thin film and a heat-meltable resin film, three layers sandwiching the metal thin film with a heat-meltable resin film, Furthermore, you may have the laminated structure beyond it. Furthermore, you may provide the protective layer of the metal thin film which consists of a polyester film etc. as needed. Among these, it is preferable that the heat-meltable resin film is located in the outermost layer of the laminate outer package. When the heat-meltable resin film is located in the outermost layer, sealing by heat-sealing can be easily performed.
本発明に使用できる金属薄膜は、電池内へ水分の進入を防ぐことができさえすれば特に限定されず、公知の材料からなる膜をいずれも使用することができる。金属薄膜としては、アルミニウム、ステンレス、ニッケル、銅等の材料からなる膜が挙げられる。金属薄膜の厚さは、５〜５０μｍ程度が好ましく、更に好ましくは１０〜３０μｍ程度である。金属薄膜が薄すぎると水分の進入を十分に防ぐことができないので好ましくない。また厚すぎると熱融着の際に、樹脂フィルムに十分に熱を伝えることができないので、熱融着後の気密信頼性が下がることとなる。更に、ラミネート外装体自体が厚くなるので、電池のエネルギー密度が低下することとなるため好ましくない。 The metal thin film that can be used in the present invention is not particularly limited as long as moisture can be prevented from entering the battery, and any film made of a known material can be used. Examples of the metal thin film include films made of materials such as aluminum, stainless steel, nickel, and copper. The thickness of the metal thin film is preferably about 5 to 50 μm, more preferably about 10 to 30 μm. If the metal thin film is too thin, it is not preferable because the ingress of moisture cannot be sufficiently prevented. On the other hand, if the thickness is too large, heat cannot be sufficiently transferred to the resin film at the time of heat-sealing, so that the airtight reliability after heat-sealing is lowered. Furthermore, since the laminate outer package itself becomes thick, the energy density of the battery is lowered, which is not preferable.
一方、熱融着性樹脂フィルムは、熱融着により電池を密閉することができさえすれば特に限定されず、公知の材料からなるフィルムをいずれも使用することができる。熱融着性樹脂フィルムとしては、熱融着性に優れたポリプロピレン、ポリエチレン、アイオノマー樹脂等からなるフィルムが挙げられる。熱融着性樹脂フィルムの厚さは、２０〜２５０μｍ程度が好ましく、その種類によっても異なるが、熱融着性、フィルム強度、膜物性の点から８０〜２００μｍの範囲がより好ましい。 On the other hand, the heat-fusible resin film is not particularly limited as long as the battery can be sealed by heat-sealing, and any film made of a known material can be used. Examples of the heat-fusible resin film include films made of polypropylene, polyethylene, ionomer resin, and the like excellent in heat-fusibility. The thickness of the heat-fusible resin film is preferably about 20 to 250 μm, and it varies depending on the type, but is more preferably in the range of 80 to 200 μm from the viewpoint of heat-fusibility, film strength, and film properties.
本発明における封止部の幅は、封止部に垂直方向の電池の幅に対して、折り曲げた状態で、３０％以下であることが好ましく、より好ましくは２０％以下、更に好ましくは１０％以下である。なお、封止部の幅をできるだけ狭くすることが、エネルギー密度の観点から好ましい。
更に、封止部の幅は、折り曲げ回数を増やすことにより適宜調節可能である。折り曲げ回数は、特に限定されないが、折り曲げた封止部の厚みが電池の最も厚い部分の厚みを越えない範囲内に納めるのが好ましい。また、封止部の幅が電池の厚みより小さい場合には、折り曲げた封止部を更に垂直に折り曲げることも可能である。垂直に折り曲げることにより、電池の投影面積を更に小さくすることができる。
In the present invention, the width of the sealing portion is preferably 30% or less, more preferably 20% or less, and still more preferably 10% in a bent state with respect to the width of the battery perpendicular to the sealing portion. It is as follows. In addition, it is preferable from a viewpoint of energy density to make the width | variety of a sealing part as narrow as possible.
Furthermore, the width of the sealing portion can be adjusted as appropriate by increasing the number of bendings. The number of times of folding is not particularly limited, but it is preferable that the thickness of the folded sealing portion is within a range not exceeding the thickness of the thickest portion of the battery. Further, when the width of the sealing portion is smaller than the thickness of the battery, the bent sealing portion can be further bent vertically. By folding vertically, the projected area of the battery can be further reduced.
本発明は封止部にタブが位置する場合に、特に効果を発揮する。タブの位置する封止部は最も気密不良を起こしやすい箇所であるが、本発明では気密信頼性を向上することが可能となる。
なお、封止部にタブが位置する場合、封止性を更に向上させるために、ラミネート外装体の封止部に熱融着性層を更に１層又は複数層積層してもよい。この熱融着性層は、上記熱融着性樹脂フィルムと同じ材料又はその変性樹脂層を使用することができる。
また、図７や８のように、タブの位置する封止部においてラミネート外装体をずらして封口し、タブを保護することも可能である。なお、図７及び８中、１６と１８はラミネート外装体、１７と１９は正極タブをそれぞれ意味している。
The present invention is particularly effective when the tab is located in the sealing portion. Although the sealing portion where the tab is located is the place where the airtight failure is most likely to occur, the present invention can improve the airtight reliability.
In addition, when a tab is located in a sealing part, in order to improve a sealing performance further, you may laminate | stack one layer or multiple layers of heat-fusible layers in the sealing part of a laminate exterior body. For this heat-fusible layer, the same material as the heat-fusible resin film or a modified resin layer thereof can be used.
Further, as shown in FIGS. 7 and 8, it is also possible to protect the tab by shifting and closing the laminate outer package at the sealing portion where the tab is located. 7 and 8,
本発明に使用できるタブは、特に限定されず公知の金属薄膜からなる。ここで、タブの厚さは、３〜２０μｍであることが好ましい。更に、タブの幅は、電池のサイズによっても異なるが、電池の気密性を考慮するとできるだけ狭いことが好ましく、また外部への電気の取り出し効率を考えると、タブ取り出し部分の電池の幅に対する割合が、５〜４０％であることが好ましく、５〜２０％であることがより好ましい。更に、タブは、気密信頼性を向上させるため、多孔体であってもよい。多孔体には、金属膜に穴をあけたパンチングメタル、又は金属膜に切り込みを入れ、引き延ばすことによって穴を作った後、プレスすることによって得られるエキスパンドメタル等を使用することができる。なお、本発明ではタブと封口部の境界に応力がかかりにくくなるので、タブ切れの問題を解消できる。特に、エキスパンドメタルやパンチングメタルのような穴のあいたタブを用いた場合は、箔状のタブに比べ機械的強度が小さいが、本発明ではこのようなタブを用いてもタブ切れを防ぐことができる。
タブは、正極及び負極（又は以下で説明する集電体）のそれぞれに溶接することにより固定することができる。タブの溶接方法は、公知の超音波溶接、抵抗溶接、レーザー溶接等を適宜使用することが可能である。
The tab that can be used in the present invention is not particularly limited and is formed of a known metal thin film. Here, the thickness of the tab is preferably 3 to 20 μm. Furthermore, the width of the tab varies depending on the size of the battery, but it is preferable that the tab is as narrow as possible in consideration of the airtightness of the battery, and considering the efficiency of taking out electricity to the outside, the ratio of the tab extraction portion to the battery width is 5 to 40% is preferable, and 5 to 20% is more preferable. Further, the tab may be a porous body in order to improve hermetic reliability. For the porous body, a punching metal in which a hole is formed in a metal film, or an expanded metal obtained by pressing after forming a hole by cutting and extending the metal film can be used. In the present invention, since it is difficult to apply stress to the boundary between the tab and the sealing portion, the problem of tab breakage can be solved. In particular, when a tab with a hole such as expanded metal or punching metal is used, the mechanical strength is smaller than that of a foil-shaped tab. it can.
The tab can be fixed by welding to each of the positive electrode and the negative electrode (or the current collector described below). As a method for welding the tab, known ultrasonic welding, resistance welding, laser welding, or the like can be used as appropriate.
また、少なくとも一回折り曲げられて封止されてなる辺に直交する辺を、ラミネート外装フィルムの裏と表を熱融着することによって封止すれば（図６参照）、封止部が直交する場所において、気密信頼性をより向上させることができる。図６中、１４はラミネート外装体、１５は電池素子をそれぞれ意味している。
ラミネート外装体により封止される電池素子は、特に限定されず少なくとも正極、イオン伝導体及び負極を有しさえすれば一次及び二次のどのような電池素子でも使用することができる。特に、小型化及び薄型化の要求が強い非水系リチウムイオン二次電池素子を使用することが好ましい。以下、非水系リチウムイオン二次電池素子について説明するが、この説明に本発明は限定されない。
Moreover, if the side orthogonal to the side that is bent and sealed at least once is sealed by thermally fusing the back and front of the laminate exterior film (see FIG. 6), the sealing part is orthogonal. In the place, the airtight reliability can be further improved. In FIG. 6, 14 indicates a laminate outer package, and 15 indicates a battery element.
The battery element to be sealed by the laminate outer package is not particularly limited, and any primary and secondary battery element can be used as long as it has at least a positive electrode, an ionic conductor, and a negative electrode. In particular, it is preferable to use a non-aqueous lithium ion secondary battery element that has a strong demand for downsizing and thinning. Hereinafter, although a non-aqueous lithium ion secondary battery element is demonstrated, this invention is not limited to this description.
正極は、一般的に、正極活物質、導電材及び結着材とからなる。
正極活物質としては、ＬｉＣｏＯ2、ＬｉＮｉＯ2に代表されるＬｉxＭ1yＭ２1-yＯ2（ここでＭ１はＦｅ、Ｃｏ、Ｎｉのいずれかであり、Ｍ２は遷移金属、４Ｂ族、又は５Ｂ族の金属を表す、０＜ｘ≦１、ｙ=０〜１）、ＬｉＭｎ2Ｏ4及びＬｉＭｎ2-ZＭ２ZＯ4（ここでＭ２は上記と同じ、０≦ｚ≦２）等のリチウムを含有したカルコゲン化合物が挙げられる。これ以外に、リチウムを含有しない、MnO2、MoO3、V2O5、V6O13等の酸化物も用いることができる。
The positive electrode is generally composed of a positive electrode active material, a conductive material, and a binder.
As the positive electrode active material, Li x M1 y M2 1-y O 2 typified by LiCoO 2 and LiNiO 2 (where M1 is any one of Fe, Co and Ni, and M2 is a transition metal, group 4B, or Representing a group 5B metal, such as 0 <x ≦ 1, y = 0 to 1, LiMn 2 O 4 and LiMn 2−Z M2 Z O 4 (where M2 is the same as above, 0 ≦ z ≦ 2), etc. Examples include lithium-containing chalcogen compounds. Other than these, oxides such as MnO 2 , MoO 3 , V 2 O 5 , and V 6 O 13 that do not contain lithium can also be used.
リチウムを含有しない酸化物を使用する場合は、負極又は正極にあらかじめリチウムを含有させておく必要がある。一方、リチウムを含有したカルコゲン化合物を用いると、電池素子が放電状態で完成されるため製造工程中の安全性や製造工程の簡略化を考えると、そのような化合物を用いることが好ましい。
導電材には、カーボンブラック（アセチレンブラック、サーマルブラック、チャンネルブラック等）等の炭素類や、グラファイト粉末、金属粉末等を用いることができるが、これに限定されるものではない。
結着材には、ポリテトラフルオロエチレン、ポリフッ化ビニリデン等のフッ素系ポリマー、ポリエチレン、ポリプロピレン等のポリオレフィン系ポリマー、合成ゴム類等を用いることができるが、これに限定されるものではない。
In the case of using an oxide not containing lithium, it is necessary to previously contain lithium in the negative electrode or the positive electrode. On the other hand, when a chalcogen compound containing lithium is used, since the battery element is completed in a discharged state, it is preferable to use such a compound in consideration of safety during the manufacturing process and simplification of the manufacturing process.
As the conductive material, carbons such as carbon black (acetylene black, thermal black, channel black, etc.), graphite powder, metal powder, and the like can be used, but are not limited thereto.
As the binder, fluorine-based polymers such as polytetrafluoroethylene and polyvinylidene fluoride, polyolefin-based polymers such as polyethylene and polypropylene, synthetic rubbers, and the like can be used, but are not limited thereto.
正極活物質、導電材及び結着材の混合比は、活物質１００重量部に対して、導電材を１〜５０重量部、結着材を１〜３０重量部とすることが好ましい。なお、導電材は１〜１０重量部、結着材は３〜１０重量部とすることがより好ましい。導電材が５重量部より小さい、又は結着材が３０重量部より大きいと、電極の内部抵抗又は分極等が大きくなり、電極の放電容量が低くなるため実用的なリチウム二次電池素子が作製できないため好ましくない。導電材が５０重量部より多いと電極内に含まれる活物質量が相対的に減るため、正極としての放電容量が低くなるため好ましくない。結着材が１重量部以上ないと活物質の結着能力がなくなり、活物質の脱落や機械的強度の低下により電池素子の作製が困難であるため好ましくない。結着材が３０重量部より多いと導電材の場合と同様に、電極内に含まれる活物質量が減り、更に、電極の内部抵抗又は分極等が大きくなり放電容量が低くなり実用的ではないため好ましくない。 The mixing ratio of the positive electrode active material, the conductive material and the binder is preferably 1 to 50 parts by weight of the conductive material and 1 to 30 parts by weight of the binder with respect to 100 parts by weight of the active material. More preferably, the conductive material is 1 to 10 parts by weight and the binder is 3 to 10 parts by weight. When the conductive material is smaller than 5 parts by weight or the binder is larger than 30 parts by weight, the internal resistance or polarization of the electrode is increased, and the discharge capacity of the electrode is reduced, so that a practical lithium secondary battery element is manufactured. It is not preferable because it cannot be done. If the amount of the conductive material is more than 50 parts by weight, the amount of active material contained in the electrode is relatively reduced, which is not preferable because the discharge capacity as the positive electrode is reduced. If the binder is not more than 1 part by weight, the binding capacity of the active material is lost, and it is not preferable because it is difficult to produce a battery element due to dropout of the active material or reduction in mechanical strength. If the binder is more than 30 parts by weight, the amount of active material contained in the electrode is reduced, and the internal resistance or polarization of the electrode is increased, resulting in a lower discharge capacity. Therefore, it is not preferable.
正極は、一般的に、正極活物質と導電材を、溶媒に溶解又は分散させた結着剤と混合することでスラリーを作製し、そのスラリーを集電体上に塗布、又は集電体中に充填した後、溶媒を除去することによって作製することができる。
また、正極作製時に、正極活物質及び導電材の集電体への結着性を向上させるために、結着材の融点前後かつ、溶媒の沸点以上の温度で熱処理を行うことが好ましい。
A positive electrode is generally prepared by mixing a positive electrode active material and a conductive material with a binder dissolved or dispersed in a solvent, and applying the slurry onto a current collector, or in a current collector It can be prepared by removing the solvent after filling in.
In addition, during the production of the positive electrode, in order to improve the binding property of the positive electrode active material and the conductive material to the current collector, it is preferable to perform heat treatment at a temperature around the melting point of the binder and at or above the boiling point of the solvent.
負極は、一般的に、負極活物質と、任意に導電材及び結着材とからなる。
負極活物質としては、リチウム金属、リチウム合金、又はリチウムを吸蔵放出可能な炭素材料や金属酸化物等が使用可能である。
The negative electrode is generally composed of a negative electrode active material, and optionally a conductive material and a binder.
As the negative electrode active material, lithium metal, a lithium alloy, a carbon material capable of occluding and releasing lithium, a metal oxide, or the like can be used.
上記負極活物質の内、安全性、サイクル特性の面から炭素材料は有望である。炭素材料としては公知の材料を使用することができ、例えば天然黒鉛、石油コークス、クレゾール樹脂焼成炭素、フラン樹脂焼成炭素、ポリアクリロニトリル焼成炭素、気相成長炭素、メソフェーズピッチ焼成炭素、結晶性の高い黒鉛粒子の表面に非晶質炭素層を形成した黒鉛材料等が挙げられる。それら炭素材料の中でも、結晶性の発達した黒鉛材料は、電池の電圧を平坦にし、エネルギー密度を大きくすることができるので好ましい。更に黒鉛材料のなかでも、黒鉛粒子の表面に非晶質炭素層を有する黒鉛材料は、電解液との副反応が少なく、ラミネート外装体によって封止された電池のように、内圧に対して弱い形状の電池の場合には特に好ましい。 Among the negative electrode active materials, carbon materials are promising in terms of safety and cycle characteristics. Known materials can be used as the carbon material. For example, natural graphite, petroleum coke, cresol resin calcined carbon, furan resin calcined carbon, polyacrylonitrile calcined carbon, vapor grown carbon, mesophase pitch calcined carbon, high crystallinity Examples thereof include a graphite material in which an amorphous carbon layer is formed on the surface of graphite particles. Among these carbon materials, a graphite material with improved crystallinity is preferable because it can flatten the battery voltage and increase the energy density. Further, among graphite materials, graphite materials having an amorphous carbon layer on the surface of graphite particles have few side reactions with the electrolytic solution, and are weak against internal pressure as in a battery sealed with a laminate outer package. It is particularly preferable in the case of a shaped battery.
上述の炭素材料を負極活物質として用いる場合には、炭素粒子と結着材とを混合して負極が形成される。この際、導電性を向上するために導電材を混合してもよい。
結着材としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレン等のフッ素系ポリマー、ポリエチレン、ポリプロピレン等のポリオレフィン系ポリマー、合成ゴム類等を用いることができるが、これに限定されるものではない。
When the above-described carbon material is used as the negative electrode active material, the negative electrode is formed by mixing carbon particles and a binder. At this time, a conductive material may be mixed in order to improve conductivity.
As the binder, fluorine polymers such as polyvinylidene fluoride and polytetrafluoroethylene, polyolefin polymers such as polyethylene and polypropylene, synthetic rubbers, and the like can be used, but are not limited thereto.
炭素材料と結着材の混合比は、重量比で９９：１〜７０：３０とすることが好ましい。結着材の重量比が３０より大きくなると、電極の内部抵抗又は分極等が大きくなり、その結果放電容量が低くなるため、実用的なリチウム二次電池が作製できないため好ましくない。また、結着材の重量比が１より小さくなると、炭素材料自身又は炭素材料と集電体との結着能力が十分でなくなり、炭素材料が脱落したり、機械的強度が低下するので、電池素子の作製が困難となるため好ましくない。 The mixing ratio of the carbon material and the binder is preferably 99: 1 to 70:30 by weight. If the weight ratio of the binder is greater than 30, it is not preferable because the internal resistance or polarization of the electrode is increased, and as a result, the discharge capacity is lowered, so that a practical lithium secondary battery cannot be produced. Further, when the weight ratio of the binder is smaller than 1, the binding capacity between the carbon material itself or the carbon material and the current collector becomes insufficient, and the carbon material falls off or the mechanical strength is lowered. It is not preferable because it is difficult to manufacture the element.
導電材には、特に限定はされないが、カーボンブラック（アセチレンブラック、サーマルブラック、チャンネルブラック等）等の炭素類や、金属粉末等を用いることができる。
負極の作製は、炭素材料を負極活物質として使用する場合、一般的に、負極活物質、溶媒に溶解又は分散させた結着材、必要に応じて導電材とを混合してスラリーを作製する。このスラリーを集電体に塗布、又は充填し、溶媒を除去することによって負極を作製することができる。この場合、結着性を向上させるため及び結着材の溶媒を除去するために、溶媒の沸点以上でかつ結着材の融点前後の温度で真空中、不活性ガス雰囲気中又は空気中で熱処理を行うのが好ましい。
The conductive material is not particularly limited, and carbons such as carbon black (acetylene black, thermal black, channel black, etc.), metal powder, and the like can be used.
In the case of using a carbon material as a negative electrode active material, the negative electrode is generally prepared by mixing a negative electrode active material, a binder dissolved or dispersed in a solvent, and a conductive material as necessary to prepare a slurry. . A negative electrode can be produced by applying or filling this slurry to a current collector and removing the solvent. In this case, in order to improve the binding property and remove the solvent of the binder, heat treatment is performed in a vacuum, in an inert gas atmosphere or in air at a temperature equal to or higher than the boiling point of the solvent and around the melting point of the binder. Is preferably performed.
正極及び負極用の集電体としては、金属単体、合金等を用いることができる。例えば、銅、ニッケル、チタン、アルミニウムやステンレス鋼等が挙げられる。また、銅、アルミニウムやステンレス鋼の表面にチタン、銀を被覆させたもの、これらの材料を酸化したものも用いることができる。集電体の形状は、箔状の他、フィルム、シート、ネット、パンチされた形状、ラス体、多孔質体、発泡体、繊維群の成形体等が用いられる。集電体の厚みは特に限定されないが、強度、導電性、電池を作製した場合のエネルギー密度の観点から１μｍ〜１ｍｍが好ましく、更に１μｍ〜１００μｍが好ましい。 As the current collector for the positive electrode and the negative electrode, a single metal, an alloy, or the like can be used. For example, copper, nickel, titanium, aluminum, stainless steel, etc. are mentioned. Moreover, the thing which coat | covered titanium and silver on the surface of copper, aluminum, and stainless steel, and the thing which oxidized these materials can also be used. As the shape of the current collector, a foil, a film, a sheet, a net, a punched shape, a lath body, a porous body, a foamed body, a molded body of a fiber group, and the like are used. The thickness of the current collector is not particularly limited, but is preferably 1 μm to 1 mm, more preferably 1 μm to 100 μm, from the viewpoints of strength, conductivity, and energy density when a battery is produced.
イオン伝導体は、特に限定はされないが、例えば有機電解液（電解質塩と有機溶媒から成り立っている）、高分子固体電解質、無機固体電解質、溶融塩等を用いることができ、この中でも高分子固体電解質を好適に用いることができる。
高分子固体電解質としては、電解質塩と電解質の解離を行う高分子から構成された物質、高分子にイオン解離基を持たせた物質等が挙げられる。
The ion conductor is not particularly limited. For example, an organic electrolyte (consisting of an electrolyte salt and an organic solvent), a polymer solid electrolyte, an inorganic solid electrolyte, a molten salt, and the like can be used. An electrolyte can be suitably used.
Examples of the polymer solid electrolyte include a substance composed of a polymer that dissociates the electrolyte salt and the electrolyte, a substance obtained by adding an ion dissociation group to the polymer, and the like.
なお、本明細書において、高分子固体電解質は、一般的に電池素子に使用される液状の電解質と区別するために使用されており、その範囲には、高分子と有機溶媒を用いたゲル状の電解質を含むものである。ゲル状の電解質は、液漏れの心配のない固体電解質の特徴と、液体に近いイオン伝導性を併せ持ち、非常に有望である。 In the present specification, the polymer solid electrolyte is generally used to distinguish it from the liquid electrolyte used in the battery element, and the range includes a gel-like material using a polymer and an organic solvent. The electrolyte is included. Gel electrolytes are very promising because they combine the characteristics of a solid electrolyte that does not cause liquid leakage and the ionic conductivity close to that of a liquid.
ゲル状の電解質の骨格となる有機化合物は、電解質の溶媒溶液と親和性があり、重合可能な官能基を有する化合物であれば、特に制限はない。例えばポリエーテル構造及び不飽和二重結合基を有するもの、オリゴエステルアクリレート、ポリエステル、ポリイミン、ポリチオエーテル、ポリサルファン、リン酸エステルポリマー等の単独もしくは二種以上の併用が挙げられる。なお、溶媒との親和性からポリエーテル構造及び不飽和二重結合基を有するものが好ましい。ポリエーテル構造単位としては、例えばエチレンオキシド、プロピレンオキシド、ブチレンオキシド、グリシジルエーテル類等が挙げられ、これらの単独又は二種以上の組み合わせが好適に用いられる。また、二種以上の組み合わせの場合、その形態はブロック、ランダムを問わず適宜選択できる。更に、不飽和二重結合基としては、例えばアリル、メタリル、ビニル、アクロイル、メタロイル基等が挙げられる。 The organic compound serving as the skeleton of the gel electrolyte is not particularly limited as long as it is a compound having an affinity for the solvent solution of the electrolyte and having a polymerizable functional group. Examples thereof include those having a polyether structure and an unsaturated double bond group, oligoester acrylates, polyesters, polyimines, polythioethers, polysulfanes, phosphate ester polymers and the like alone or in combination of two or more. In addition, those having a polyether structure and an unsaturated double bond group are preferred from the viewpoint of affinity with a solvent. Examples of the polyether structural unit include ethylene oxide, propylene oxide, butylene oxide, glycidyl ethers and the like, and these are used alone or in combination of two or more. In the case of a combination of two or more, the form can be selected as appropriate regardless of whether it is a block or random. Furthermore, examples of the unsaturated double bond group include allyl, methallyl, vinyl, acroyl, metalloyl groups and the like.
また、ゲル状の電解質に用いる有機溶媒としては、プロピレンカーボネート（ＰＣ）、エチレンカーボネート（ＥＣ）、ブチレンカーボネート等の環状カーボネート類、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、ジプロピルカーボネート等の鎖状カーボネート類、γ−ブチロラクトン、γ−バレロラクトン等のラクトン類、テトラヒドロフラン、２−メチルテトラヒドロフラン等のフラン類、ジエチルエーテル、１，２−ジメトキシエタン、１，２−ジエトキシエタン、エトキシメトキシエタン、ジオキサン等のエーテル類、ジメチルスルホキシド、スルホラン、メチルスルホラン、アセトニトリル、ギ酸メチル、酢酸メチル等が挙げられる。 Moreover, as an organic solvent used for the gel electrolyte, cyclic carbonates such as propylene carbonate (PC), ethylene carbonate (EC), and butylene carbonate, chain chains such as dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, and dipropyl carbonate are used. Lactones such as carbonates, γ-butyrolactone, γ-valerolactone, furans such as tetrahydrofuran, 2-methyltetrahydrofuran, diethyl ether, 1,2-dimethoxyethane, 1,2-diethoxyethane, ethoxymethoxyethane, dioxane And ethers such as dimethyl sulfoxide, sulfolane, methyl sulfolane, acetonitrile, methyl formate, and methyl acetate.
電解質塩として、過塩素酸リチウム(LiClO4)、ホウフッ化リチウム(LiBF4)、リンフッ化リチウム(LiPF6)、6フッ化砒酸リチウム(LiAsF6)、6フッ化アンチモン酸リチウム(LiSbF6)、トリフルオロメタンスルホン酸リチウム(LiCF3SO3)、トリフルオロ酢酸リチウム(LiCF3COO)、ハロゲン化リチウム、塩化アルミン酸リチウム(LiAlCl4)、トリフルオロメタンスルホン酸イミドリチウム（LiN（CF3SO2）2）等のリチウム塩が挙げられ、これらの１種以上を混合して用いることができる。
As an electrolyte salt, lithium perchlorate (LiClO 4), lithium borofluoride (LiBF 4), Rinfu' lithium (
ゲル状の固体電解質は、前記で選ばれた溶媒に電解質塩を溶解することによって電解液を調製し、上記有機化合物と混合し、重合させることによって得られる。
重合方法は、熱重合、光重合、放射線重合等が挙げられる。熱重合開始剤、光重合開始剤は当業者において公知のものを使用できる。また重合開始剤の量は、組成等によって適宜選択できる。
The gel-like solid electrolyte is obtained by preparing an electrolytic solution by dissolving an electrolyte salt in the solvent selected above, mixing with the organic compound, and polymerizing.
Examples of the polymerization method include thermal polymerization, photopolymerization, and radiation polymerization. As the thermal polymerization initiator and the photopolymerization initiator, those known to those skilled in the art can be used. The amount of the polymerization initiator can be appropriately selected depending on the composition and the like.
ゲル電解質の別の製法として、電解液に膨潤するポリマーを電極中にあらかじめ混合した電極を作製し、後から電解液によって膨潤させることによってゲル状の電解質を作製することも可能である。
また、イオン伝導体には、有機溶媒に電解質塩を溶解した、有機電解液を用いることも可能である。更に、無機固体電解質を使用してもよく、その電解質としては、Liの窒化物、ハロゲン化物、酸素酸塩等が知られている。具体的には、Li3N、LiI、Li3N-LiI-LiOH、LiSiO4、LiSiO4-LiI-LiOH、Li3PO4-Li4SiO4、硫化リン化合物、Li2SiS3等がある。
また、無機固体電解質と有機固体電解質を併用してもよい。
As another method for producing a gel electrolyte, it is also possible to produce an electrode in which a polymer that swells in an electrolytic solution is mixed in advance in the electrode, and later swelled with the electrolytic solution to produce a gel electrolyte.
In addition, an organic electrolyte solution in which an electrolyte salt is dissolved in an organic solvent can be used as the ion conductor. In addition, an inorganic solid electrolyte may be used, and as the electrolyte, Li nitride, halide, oxyacid salt, and the like are known. Specific examples include Li 3 N, LiI, Li 3 N—LiI—LiOH, LiSiO 4 , LiSiO 4 —LiI—LiOH, Li 3 PO 4 —Li 4 SiO 4 , phosphorus sulfide compounds, Li 2 SiS 3 and the like. .
Moreover, you may use together an inorganic solid electrolyte and an organic solid electrolyte.
以下、実施例により本発明を具体的に説明するが、これによって本発明が何ら影響を受けるものではない。なお、以下の実施例において、Ｘ線広角回折法による平均面間隔ｄ(002)又は結晶子の大きさ（Ｌｃ、Ｌａ）を測定する方法は、"炭素材料実験技術１、ｐ．５５〜６３、炭素材料学会編（科学技術社）"に記載された方法を用いた。Ｌｃ、 Ｌａを求めるための形状因子Ｋは０．９を用いた。また、粒子の比表面積はＢＥＴ法により測定し、粒径及び粒度分布はレーザー回折式粒度分布計を用い測定し、粒径は粒度分布におけるピークを平均粒径とした。Ｒ値は５１４．５ｎｍのアルゴンレーザーを用いたラマン分光測定法により観察される２本のピークより、１３６０ｃｍ-1付近のピーク強度Ｉ１３６０と１５８０ｃｍ-1付近のピーク強度Ｉ１５８０の強度比、つまりＲ値＝Ｉ１３６０／Ｉ１５８０として求めた。
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not influenced at all by this. In the following examples, the method of measuring the average interplanar spacing d (002) or crystallite size (Lc, La) by the X-ray wide angle diffraction method is described in “Carbon
ラマン分光測定において、１５８０ｃｍ-1付近のピークは黒鉛構造に起因し、１３６０ｃｍ-1付近のピークは黒鉛構造の乱れによるものであり、そのピークの強度比によって黒鉛の結晶性が評価可能である。ピーク位置は黒鉛の結晶性、原料、焼成条件等によって若干シフトするため、本評価方法の場合はその付近に現れるピークのピークトップの強度を用いてピーク強度比を算出した。 In Raman spectroscopy, the peak around 1580 cm -1 is due to the graphite structure, the peak around 1360 cm -1 is due to disturbance of the graphite structure, the crystallinity of graphite can be evaluated by the intensity ratio of the peak. Since the peak position slightly shifts depending on the crystallinity of graphite, raw materials, firing conditions, etc., in the case of this evaluation method, the peak intensity ratio was calculated using the intensity of the peak top of the peak appearing in the vicinity.
実施例１（参考例）
電極の作製
・正極の作製
正極活物質にコバルト酸リチウム（ＬｉＣｏＯ2）を使用した。結着材としてのポリフッ化ビニリデンを、一旦乳鉢で溶媒としてのＮ−メチル−２−ピロリドンに溶かして結着材溶液を得た。上記正極活物質とアセチレンブラック（導電材）と混合し、これを結着材溶液に分散させ、ペーストを作製した。得られたペーストをアルミニウム箔からなる集電体上に塗布し、これを６０℃で仮乾燥、１５０℃で熱処理後プレスした。電極サイズを3.5×3ｃｍ（塗工部3×3ｃｍ）とし、無塗工部にアルミニウム箔（50μｍ）からなるタブを溶接した。更に水分除去のために１８０℃で減圧乾燥し、これを試験用の正極として用いた。塗布密度は2.9g/ｃｍ3、塗布厚は64μｍであった。
Example 1 (reference example)
Electrode Production / Positive Electrode Production Lithium cobaltate (LiCoO 2 ) was used as the positive electrode active material. Polyvinylidene fluoride as a binder was once dissolved in N-methyl-2-pyrrolidone as a solvent in a mortar to obtain a binder solution. The above positive electrode active material and acetylene black (conductive material) were mixed and dispersed in a binder solution to prepare a paste. The obtained paste was applied onto a current collector made of an aluminum foil, pre-dried at 60 ° C., heat-treated at 150 ° C. and pressed. The electrode size was 3.5 × 3 cm (coated
・負極の作製
負極活物質に人造黒鉛ＭＣＭＢ（粒径12μｍ、d(002)=0.337ｎｍ、R値＝0.4）を用いた。結着材としてのポリフッ化ビニリデンを、一旦乳鉢で溶媒としてのＮ−メチル−２−ピロリドンに溶かして結着材溶液を得た。上記負極活物質を結着材溶液に分散させ、ペーストを作製した。得られたペーストを、２０μｍの厚さの銅箔からなる集電体上に塗布し、これを６０℃で仮乾燥、２４０℃で熱処理後プレスした。電極サイズを3.5×3ｃｍ（塗工部3×3ｃｍ）とし、無塗工部にニッケル箔（50μｍ）のタブを溶接した。更に水分除去のために２００℃で真空乾燥し、これを試験用の負極として用いた。塗布密度は1.4g/ｃｍ3、塗布厚は59μｍであった。
-Manufacture of negative electrode Artificial graphite MCMB (particle size 12 micrometers, d (002) = 0.337 nm, R value = 0.4) was used for the negative electrode active material. Polyvinylidene fluoride as a binder was once dissolved in N-methyl-2-pyrrolidone as a solvent in a mortar to obtain a binder solution. The negative electrode active material was dispersed in a binder solution to prepare a paste. The obtained paste was applied onto a current collector made of a copper foil having a thickness of 20 μm, preliminarily dried at 60 ° C., heat treated at 240 ° C. and pressed. The electrode size was 3.5 × 3 cm (
電池の作製
・ゲル状の電解質をイオン伝導体として使用した電池
1MのLiPF6を溶解したエチレンカーボネート（以下EC）とジエチルカーボネート（以下DEC）の１：１（体積比）からなる溶液５０ｇに、エチレンオキシド・プロピレンオキシド・ジアクリレート共重合体（分子量２０００）１０ｇを溶解し、更に重合開始剤を０．０６ｇ加えた。
この溶液をポリプロピレン製の不織布（厚さ２０μｍ）に含浸させ、ガラス板に挾み、紫外線を照射することによりゲル化させ、ゲル状の電解質を得た。
正極及び負極に、上記溶液を含浸した後、ガラス板に挟み、紫外線を照射することによりゲル化させ、ゲル状の電解質を含む複合電極を得た。このようにして得られた電極及び電解質層を重ね合わせることによって、電池素子を作製した。
Battery fabrication / Battery using gel electrolyte as ionic conductor
To 50 g of a solution consisting of 1: 1 (volume ratio) of ethylene carbonate (hereinafter EC) and diethyl carbonate (hereinafter DEC) in which 1M LiPF 6 is dissolved, 10 g of an ethylene oxide / propylene oxide / diacrylate copolymer (molecular weight 2000). After dissolution, 0.06 g of a polymerization initiator was further added.
This solution was impregnated into a nonwoven fabric made of polypropylene (thickness: 20 μm), rubbed into a glass plate, and gelled by irradiating with ultraviolet rays to obtain a gel electrolyte.
The positive electrode and the negative electrode were impregnated with the above solution, and then sandwiched between glass plates and gelled by irradiation with ultraviolet rays to obtain a composite electrode containing a gel electrolyte. A battery element was produced by superimposing the electrode and the electrolyte layer thus obtained.
得られた電池を図１に示すように、２辺（紙面に対して左右の斜線部）をシールした（シール幅5ｍｍ）ラミネートパックに挿入し、タブ導出部を有する辺を図２に示すように封口し（投影封口幅5ｍｍ、実際の封口幅1ｃｍ）、試験用の封止された電池を得た。ここで使用したラミネートパックを構成するラミネート外装体は、アルミニウム箔をポリエチレンからなる熱融着性樹脂フィルムで挟んだものを使用した。
なお、図１中、１は正極タブ、２は負極タブ、３は封止部を意味する。また、図２は、図１のＸ−Ｘ線の断面図であり、図中、４は正極タブ、５はラミネート外装体を意味している。
As shown in FIG. 1, the obtained battery was inserted into a laminate pack (sealed
In FIG. 1, 1 is a positive electrode tab, 2 is a negative electrode tab, and 3 is a sealing portion. 2 is a cross-sectional view taken along the line XX of FIG. 1, in which 4 indicates a positive electrode tab and 5 indicates a laminate outer package.
・電解液をイオン伝導体として使用した電池
上記正極と負極の間に、セパレータ（ポリプロピレン製２５μｍ）を挟み、この電池素子を図１に示す、２辺をシールしたラミネートパックに挿入した。ラミネートパック内に、電解液として1MのLiPF6／EC：DECを注液した後、タブ導出部を図２に示すように封口し、試験用の電池を得た。
上記製法により、ゲル状の電解質を使用した電池３個、電解液を使用した電池３個を作製した。充電条件を定電流、定電圧充電（電圧値4.1V、電流値1.8ｍA、125時間充電）、放電条件を電流値を1.8ｍA、終止電圧を2.75Vとし、上記電池の充放電サイクル試験を行った。電池の容量（初回、１００サイクル目）、及びサイクル劣化率（１００サイクル目の容量／初回の容量）を表１に示す。
-Battery using electrolytic solution as ion conductor A separator (25 μm made of polypropylene) was sandwiched between the positive electrode and the negative electrode, and this battery element was inserted into a laminate pack having two sides sealed as shown in FIG. After injecting 1M LiPF 6 / EC: DEC as an electrolyte into the laminate pack, the tab lead-out portion was sealed as shown in FIG. 2 to obtain a test battery.
By the above manufacturing method, three batteries using a gel electrolyte and three batteries using an electrolytic solution were produced. Charge / discharge cycle test of the above battery was performed with charging conditions of constant current, constant voltage charging (voltage value 4.1V, current value 1.8mA, charging for 125 hours), discharge conditions of current value 1.8mA and end voltage 2.75V. It was. Table 1 shows the battery capacity (first time, 100th cycle) and the cycle deterioration rate (100th cycle capacity / first time capacity).
比較例１
図３及び４に示すように、タブ導出部を有する辺について、封口部（封口幅5ｍｍ）を折り曲げずに封口したこと以外は実施例１と同様にゲル状の電解質を使用した電池３個、電解液を使用した電池３個を作製し、サイクル試験を行った。電池の容量（初回、１００サイクル目）、及びサイクル劣化率（１００サイクル目の容量／初回の容量）を表１に示す。
なお、図３中、６は正極タブ、７は負極タブ、８は封止部を意味する。また、図４は、図３のＸ−Ｘ線の断面図であり、図中、９はラミネート外装体、１０は正極タブを意味している。
Comparative Example 1
As shown in FIGS. 3 and 4, for the side having the tab lead-out part, three batteries using a gel electrolyte as in Example 1 except that the sealing part (
In FIG. 3, 6 indicates a positive electrode tab, 7 indicates a negative electrode tab, and 8 indicates a sealing portion. FIG. 4 is a cross-sectional view taken along line XX of FIG. 3, in which 9 indicates a laminate outer package and 10 indicates a positive electrode tab.
以上の結果より、タブが導出される封口部を折り曲げることによって、同じシール幅でも実際は封止部の幅を２倍とすることが可能となり、気密信頼性が向上し、良好なサイクル特性が得られることがわかる。また、封口部を折り曲げずに作製した比較例では、極端にサイクル特性が悪い電池がみられ、封止の信頼性が低いことがわかった。これは、気密信頼性が十分ではなく、空気中の水分が電池中に進入してしまったためであると考えられる。 From the above results, it is possible to actually double the width of the sealing portion even with the same seal width by bending the sealing portion from which the tab is led out, improving airtight reliability and obtaining good cycle characteristics. I understand that Moreover, in the comparative example produced without bending a sealing part, the battery with extremely bad cycling characteristics was seen, and it turned out that the reliability of sealing is low. This is considered to be because the airtight reliability is not sufficient and moisture in the air has entered the battery.
実施例２（参考例）
電極の電流取り出し用のタブとして、正極側にはアルミニウムのパンチングメタル（50μｍ、開口率50%）、負極側にはニッケルのパンチングメタル（５０μｍ、開口率50%）を用いた。またゲル状の電解質の溶液として、1MのLiBF4を溶解したECとγ−ブチロラクトン（以下GBL）の1:1（体積比）溶液を用いた。封止部を、図７に示すようしたこと以外は、実施例１と同様にしてゲル状の電解質を使用した電池を作製した。作製した電池について実施例１と同様の試験を行った結果を表２に示す。
なお、図７中、１６はラミネート外装体、１７は正極タブを意味している。
Example 2 (reference example)
An aluminum punching metal (50 μm, opening ratio 50%) was used on the positive electrode side, and a nickel punching metal (50 μm, opening ratio 50%) was used on the negative electrode side as a tab for taking out current from the electrode. As the gel electrolyte solution, a 1: 1 (volume ratio) solution of EC and γ-butyrolactone (hereinafter referred to as GBL) in which 1M LiBF 4 was dissolved was used. A battery using a gel electrolyte was produced in the same manner as in Example 1 except that the sealing portion was as shown in FIG. Table 2 shows the results of the same tests as in Example 1 for the fabricated batteries.
In FIG. 7, 16 denotes a laminate outer package, and 17 denotes a positive electrode tab.
比較例２
電極の電流取り出し用のタブとして、正極側にはアルミニウムのパンチングメタル（50μｍ、開口率50%）、負極側にはニッケルのパンチングメタル（５０μｍ、開口率50%）を用いた。また、ゲル状の電解質の溶液として、1MのLiBF4を溶解したECとGBLの1:1（体積比）溶液を用いた。それ以外は比較例１と同様にしてゲル状の電解質を使用した電池を作製した。作製した電池について実施例１と同様の試験を行った結果を表２に示す。なお、比較例２の電池の内の１つは正極タブが切れてしまい評価できなかった。
Comparative Example 2
An aluminum punching metal (50 μm, opening ratio 50%) was used on the positive electrode side, and a nickel punching metal (50 μm, opening ratio 50%) was used on the negative electrode side as a tab for taking out current from the electrode. As the gel electrolyte solution, a 1: 1 (volume ratio) solution of EC and GBL in which 1M LiBF 4 was dissolved was used. Otherwise, a battery using a gel electrolyte was prepared in the same manner as in Comparative Example 1. Table 2 shows the results of the same tests as in Example 1 for the fabricated batteries. In addition, one of the batteries of Comparative Example 2 could not be evaluated because the positive electrode tab was cut.
以上の結果より、パンチングメタルのようなタブを用いた場合、従来の方法でもある程度気密信頼性は向上し、サイクル特性はよくなる。しかし、本発明のように、封口部を折り曲げることによって更に気密信頼性が向上し、良好なサイクル特性が得られる。また、封止部を折り曲げることにより、タブが封止部、又は電池面と重なった状態になるため、タブの付け根に直接応力がかかりにくくなる。その結果、タブ切れの問題も解消できる。 From the above results, when a tab such as punching metal is used, the hermetic reliability is improved to some extent even with the conventional method, and the cycle characteristics are improved. However, as in the present invention, the hermetic reliability is further improved by bending the sealing portion, and good cycle characteristics can be obtained. Further, since the tab is overlapped with the sealing portion or the battery surface by bending the sealing portion, it is difficult to apply stress directly to the base of the tab. As a result, the problem of tab breaks can be solved.
実施例３
炭素材料として、黒鉛の表面にピッチをコーティングし、焼成することによって非晶質炭素層を形成した黒鉛材料（（粒径15μｍ、d(002)=0.336ｎｍ、R値＝0.38）以下PCG）を用いたこと以外は実施例１と同様に負極を作製した。またゲル状の電解質の溶液に1M濃度でLiPF6を溶解させたプロピレンカーボネート（以下PC）とGBLの1：４（体積比）の溶液を用いた。それ以外は実施例１と同様にして、ゲル状の電解質を使用した電池素子を作製した。そのようにして得られた電池素子を図５及び６に示す、長辺を重ねた状態で封止し、端部を折り曲げ、封止した袋に挿入し、封止部を図８のようにすること以外は実施例１と同様に電池を作製した。
Example 3
As a carbon material, a graphite material ((Granularity 15 μm, d (002) = 0.336 nm, R value = 0.38) or less PCG) in which an amorphous carbon layer is formed by coating pitch on the surface of graphite and firing. A negative electrode was produced in the same manner as in Example 1 except that it was used. A 1: 4 (volume ratio) solution of propylene carbonate (hereinafter PC) and GBL in which LiPF 6 was dissolved at a concentration of 1 M in a gel electrolyte solution was used. Other than that was carried out similarly to Example 1, and produced the battery element which uses a gel-like electrolyte. The battery element thus obtained is sealed with the long sides overlapped as shown in FIGS. 5 and 6, the end is bent and inserted into the sealed bag, and the sealed portion is as shown in FIG. A battery was fabricated in the same manner as in Example 1 except that.
なお、図５中、１１は正極タブ、１２は負極タブ、１３は封止部を意味する。図６は、図５のＹ−Ｙ線の断面図であり、図中１４はラミネート外装体、１５は電池素子を意味する。図８は、図５のＸ−Ｘ線の断面図であり、図中１８はラミネート外装体、１９は正極タブを意味する。
得られた電池について、実施例１と同様に電池の試験を行った。結果を表３に示す。
また、実施例１と実施例３の電池の低温特性（-20℃）を測定した。結果を表４に示す。
In FIG. 5, 11 denotes a positive electrode tab, 12 denotes a negative electrode tab, and 13 denotes a sealing portion. 6 is a cross-sectional view taken along line YY of FIG. 5, in which 14 denotes a laminate outer package, and 15 denotes a battery element. FIG. 8 is a cross-sectional view taken along line XX of FIG. 5, in which 18 denotes a laminate outer package, and 19 denotes a positive electrode tab.
The obtained battery was tested in the same manner as in Example 1. The results are shown in Table 3.
Further, the low temperature characteristics (−20 ° C.) of the batteries of Example 1 and Example 3 were measured. The results are shown in Table 4.
比較例３
炭素材料として、人造黒鉛（TIMCAL社製KS-25、粒径12μｍ、d(002)=0.336ｎｍ、R値＝0.15）を用いたこと以外は実施例１と同様に電池を作製した。
ラミネート外装体の両端（図７の１６及び１７の部分）を折り曲げずに封止したこと以外は実施例３と同様に電池を作製した。そのようにして作製した電池について実施例１と同様に充放電試験を行った。結果を表３に示す。なお、3個作製した電池のうち一つはタブの部分で封口部が開いていたため評価できなかった。
Comparative Example 3
A battery was fabricated in the same manner as in Example 1 except that artificial graphite (KS-25 manufactured by TIMCAL, particle size 12 μm, d (002) = 0.336 nm, R value = 0.15) was used as the carbon material.
A battery was fabricated in the same manner as in Example 3 except that both ends (
以上の比較より、黒鉛材料の表面に非晶質炭素層を形成した黒鉛を使用した場合、従来黒鉛材料を用いた場合におこるPCの分解が抑えられることによってPCが使用可能になることが分かった。
更に、上記黒鉛とＰＣの組み合わせに、本願発明の封止方法を採用することによって、気密信頼性があがるため、高信頼性の電池を得ることができた。
From the above comparison, it is clear that when graphite with an amorphous carbon layer formed on the surface of graphite material is used, PC can be used by suppressing the decomposition of PC that occurs when using conventional graphite material. It was.
Further, by adopting the sealing method of the present invention to the combination of graphite and PC, the airtight reliability is improved, so that a highly reliable battery can be obtained.
一方、負極材料に従来の黒鉛材料を用いた場合、電解液中にPCが存在すると、充放電効率がきわめて低くなり、正極のリチウムが消費され、十分な容量が得られなかった。これはPCの分解によるガス発生によって、固−固界面が壊され、電池の特性が悪くなったためであると考えられる。
また、プロピレンカーボネートはエチレンカーボネートに比べ融点が低いために、実施例３で得られた電池は良好な低温特性が得られた。
On the other hand, when a conventional graphite material is used as the negative electrode material, if PC is present in the electrolyte, the charge / discharge efficiency is extremely low, lithium of the positive electrode is consumed, and sufficient capacity cannot be obtained. This is thought to be because the solid-solid interface was broken by the generation of gas due to the decomposition of the PC, and the characteristics of the battery deteriorated.
In addition, since propylene carbonate has a lower melting point than ethylene carbonate, the battery obtained in Example 3 has good low-temperature characteristics.
１、４、６、１０、１１、１７、１９ 正極タブ
２、７、１２ 負極タブ
３、８、１３ 封止部
５、９、１４、１６、１８ ラミネート外装体
１５ 電池素子
1, 4, 6, 10, 11, 17, 19
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