JP2012064313A - Battery - Google Patents
Battery Download PDFInfo
- Publication number
- JP2012064313A JP2012064313A JP2010204998A JP2010204998A JP2012064313A JP 2012064313 A JP2012064313 A JP 2012064313A JP 2010204998 A JP2010204998 A JP 2010204998A JP 2010204998 A JP2010204998 A JP 2010204998A JP 2012064313 A JP2012064313 A JP 2012064313A
- Authority
- JP
- Japan
- Prior art keywords
- negative electrode
- main body
- mixture layer
- battery
- current collector
- 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
- 239000000203 mixture Substances 0.000 claims abstract description 104
- 230000002093 peripheral effect Effects 0.000 claims abstract description 36
- 238000007789 sealing Methods 0.000 claims description 28
- 229920005992 thermoplastic resin Polymers 0.000 claims description 11
- 239000008151 electrolyte solution Substances 0.000 claims description 6
- 239000007774 positive electrode material Substances 0.000 claims description 5
- 239000003792 electrolyte Substances 0.000 abstract description 3
- 239000011230 binding agent Substances 0.000 description 20
- 229910052751 metal Inorganic materials 0.000 description 15
- 239000002184 metal Substances 0.000 description 15
- 238000000034 method Methods 0.000 description 13
- 229910052744 lithium Inorganic materials 0.000 description 11
- 238000003466 welding Methods 0.000 description 11
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 10
- 239000007773 negative electrode material Substances 0.000 description 10
- -1 polyethylene terephthalate Polymers 0.000 description 8
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 7
- 238000004519 manufacturing process Methods 0.000 description 7
- 229920005989 resin Polymers 0.000 description 7
- 239000011347 resin Substances 0.000 description 7
- 239000003795 chemical substances by application Substances 0.000 description 6
- 238000004080 punching Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 239000002033 PVDF binder Substances 0.000 description 5
- 239000011888 foil Substances 0.000 description 5
- 229920002981 polyvinylidene fluoride Polymers 0.000 description 5
- 239000002904 solvent Substances 0.000 description 5
- XTHFKEDIFFGKHM-UHFFFAOYSA-N Dimethoxyethane Chemical compound COCCOC XTHFKEDIFFGKHM-UHFFFAOYSA-N 0.000 description 4
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 4
- 239000003575 carbonaceous material Substances 0.000 description 4
- 238000005304 joining Methods 0.000 description 4
- 238000002844 melting Methods 0.000 description 4
- 230000008018 melting Effects 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 3
- 229910000733 Li alloy Inorganic materials 0.000 description 3
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 3
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 3
- 239000004743 Polypropylene Substances 0.000 description 3
- 239000012752 auxiliary agent Substances 0.000 description 3
- 238000010030 laminating Methods 0.000 description 3
- 239000001989 lithium alloy Substances 0.000 description 3
- 229910001416 lithium ion Inorganic materials 0.000 description 3
- 239000002609 medium Substances 0.000 description 3
- 229920001155 polypropylene Polymers 0.000 description 3
- 229920003048 styrene butadiene rubber Polymers 0.000 description 3
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 description 3
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 description 2
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 239000002174 Styrene-butadiene Substances 0.000 description 2
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 239000012736 aqueous medium Substances 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000001768 carboxy methyl cellulose Substances 0.000 description 2
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 2
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 2
- 239000002482 conductive additive Substances 0.000 description 2
- 239000000470 constituent Substances 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 239000010949 copper Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000010438 heat treatment Methods 0.000 description 2
- 239000005001 laminate film Substances 0.000 description 2
- 150000002642 lithium compounds Chemical class 0.000 description 2
- 229910003002 lithium salt Inorganic materials 0.000 description 2
- 159000000002 lithium salts Chemical class 0.000 description 2
- 239000002905 metal composite material Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 229920000139 polyethylene terephthalate Polymers 0.000 description 2
- 239000005020 polyethylene terephthalate Substances 0.000 description 2
- 229920000098 polyolefin Polymers 0.000 description 2
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 2
- 239000004810 polytetrafluoroethylene Substances 0.000 description 2
- 238000000926 separation method Methods 0.000 description 2
- 239000002002 slurry Substances 0.000 description 2
- 239000010936 titanium Substances 0.000 description 2
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 2
- 229910052723 transition metal Inorganic materials 0.000 description 2
- YFNKIDBQEZZDLK-UHFFFAOYSA-N triglyme Chemical compound COCCOCCOCCOC YFNKIDBQEZZDLK-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
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 description 1
- SBASXUCJHJRPEV-UHFFFAOYSA-N 2-(2-methoxyethoxy)ethanol Chemical compound COCCOCCO SBASXUCJHJRPEV-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910018871 CoO 2 Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 229910000881 Cu alloy Inorganic materials 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910013372 LiC 4 Inorganic materials 0.000 description 1
- 229910013684 LiClO 4 Inorganic materials 0.000 description 1
- 229910013870 LiPF 6 Inorganic materials 0.000 description 1
- 229910012513 LiSbF 6 Inorganic materials 0.000 description 1
- 239000004677 Nylon Substances 0.000 description 1
- 239000004642 Polyimide Substances 0.000 description 1
- JFBZPFYRPYOZCQ-UHFFFAOYSA-N [Li].[Al] Chemical compound [Li].[Al] JFBZPFYRPYOZCQ-UHFFFAOYSA-N 0.000 description 1
- 239000006230 acetylene black Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 1
- 239000003830 anthracite Substances 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 229910021383 artificial graphite Inorganic materials 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 239000006229 carbon black Substances 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 239000000571 coke Substances 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- 150000005676 cyclic carbonates Chemical class 0.000 description 1
- SBZXBUIDTXKZTM-UHFFFAOYSA-N diglyme Chemical compound COCCOCCOC SBZXBUIDTXKZTM-UHFFFAOYSA-N 0.000 description 1
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000839 emulsion Substances 0.000 description 1
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- XGZVUEUWXADBQD-UHFFFAOYSA-L lithium carbonate Chemical compound [Li+].[Li+].[O-]C([O-])=O XGZVUEUWXADBQD-UHFFFAOYSA-L 0.000 description 1
- 229910052808 lithium carbonate Inorganic materials 0.000 description 1
- FUJCRWPEOMXPAD-UHFFFAOYSA-N lithium oxide Chemical compound [Li+].[Li+].[O-2] FUJCRWPEOMXPAD-UHFFFAOYSA-N 0.000 description 1
- 229910001947 lithium oxide Inorganic materials 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 229910021382 natural graphite Inorganic materials 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 239000011255 nonaqueous electrolyte Substances 0.000 description 1
- 229920001778 nylon Polymers 0.000 description 1
- 229920001721 polyimide Polymers 0.000 description 1
- 229920000306 polymethylpentene Polymers 0.000 description 1
- 239000011116 polymethylpentene Substances 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 description 1
- 239000010935 stainless steel Substances 0.000 description 1
- 229910001220 stainless steel Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
Landscapes
- Primary Cells (AREA)
- Secondary Cells (AREA)
- Connection Of Batteries Or Terminals (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は、高い信頼性を有し、生産性が良好な電池に関するものである。 The present invention relates to a battery having high reliability and good productivity.
複数の正極と複数の負極とを交互に積層して構成した電極群を有する電池としては、例えば、外装ケースと封口ケースとガスケットにより構成される電池容器を有し、一般にコイン形電池やボタン形電池と称される扁平形の電池が知られている。 As a battery having an electrode group configured by alternately laminating a plurality of positive electrodes and a plurality of negative electrodes, for example, it has a battery container composed of an outer case, a sealing case and a gasket, and is generally a coin-type battery or a button type A flat battery called a battery is known.
前記のような扁平形の電池では、正極および負極に、集電体の片面または両面に正極合剤層や負極合剤層などの負極剤層を形成し、かつ集電体の一部を、正極合剤層や負極合剤層などの負極剤層を形成せずに露出させ、これを集電タブとして利用し、各正極および各負極の集電タブを、それぞれ纏めて溶接などし、これらの纏めた集電タブを、端子を兼ねる外装ケースや封口ケースの内面と溶接などして電気的に接続しているものがある(例えば、特許文献1)。 In the flat battery as described above, a negative electrode layer such as a positive electrode mixture layer or a negative electrode mixture layer is formed on one or both sides of the current collector on the positive electrode and the negative electrode, and a part of the current collector is formed. The negative electrode layer such as the positive electrode mixture layer and the negative electrode mixture layer is exposed without being formed, and this is used as a current collecting tab, and the current collecting tabs of each positive electrode and each negative electrode are collectively welded. The current collecting tabs are electrically connected to the inner surface of an outer case or sealing case that also serves as a terminal (for example, Patent Document 1).
ところで、前記のような電極群を有する電池に係る負極では、負極合剤層を、例えば、負極活物質やバインダを含む負極合剤を媒体に分散または溶解させて調製した負極合剤含有組成物を集電体表面に塗布し、乾燥する工程を経て形成することが一般的である。そして、この場合、生産コストや環境負荷低減の観点から、負極合剤含有組成物には、水系の媒体(水を主成分とする媒体)が使用されることが多い。 By the way, in the negative electrode which concerns on the battery which has the above electrode groups, the negative mix layer prepared by disperse | distributing or dissolving the negative mix layer containing a negative electrode active material and a binder in a medium, for example. Is generally applied to the surface of the current collector and then dried. In this case, an aqueous medium (medium containing water as a main component) is often used for the negative electrode mixture-containing composition from the viewpoint of reducing production costs and environmental burdens.
よって、負極合剤層に使用するバインダには、水系の媒体に良好に分散または溶解し得る性質のものが使用されるが、このようなバインダは、例えば、電池の正極用のバインダとして汎用されているポリフッ化ビニリデン(PVDF)などに比べると結着力が小さい。そのため、特に負極では、電池の製造段階や使用段階において、負極合剤層からの微小片(負極活物質などの微小片)の脱落が生じやすく、これが電池の信頼性や生産性の低下に一因となる虞がある。 Therefore, the binder used for the negative electrode mixture layer is of a property that can be well dispersed or dissolved in an aqueous medium. Such a binder is widely used as a binder for the positive electrode of a battery, for example. Compared with polyvinylidene fluoride (PVDF) and the like, the binding force is small. Therefore, particularly in the negative electrode, minute pieces (small pieces such as the negative electrode active material) are likely to fall off from the negative electrode mixture layer in the battery production stage and use stage, which contributes to a decrease in battery reliability and productivity. There is a risk of this.
このようなことから、負極合剤層に結着力の小さなバインダを使用した場合であっても、負極合剤層からの微小片の脱落を抑制して、電池の信頼性や生産性を高める技術の開発が求められる。 For this reason, even when a binder with a small binding force is used for the negative electrode mixture layer, it is possible to suppress the removal of small pieces from the negative electrode mixture layer, thereby improving battery reliability and productivity. Development is required.
本発明は、前記事情に鑑みてなされたものであり、その目的は、高い信頼性を有し、生産性が良好な電池を提供することにある。 The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a battery having high reliability and good productivity.
前記目的を達成し得た本発明の電池は、複数の正極と複数の負極とがセパレータを介して交互に積層されており、最外部側に位置する電極の少なくとも一方が負極である電極群、および電解液を有する電池であって、前記負極は、本体部と、平面視で、前記本体部から突出した、前記本体部よりも幅の狭い集電タブ部とを有しており、電極群の最外部側の負極以外の負極には、その本体部の両面に負極合剤層が形成されており、その集電タブ部には、集電体に負極合剤層が形成されておらず、電極群の最外部側に位置する2枚の負極には、その本体部における電極群の最外部側とは反対側の面にのみ負極合剤層が形成されており、その本体部における電極群の最外部側の面および集電タブ部には、集電体に負極合剤層が形成されておらず、集電体の外周部が、負極合剤層の端面の少なくとも一部を覆っていることを特徴とするものである。 The battery of the present invention that can achieve the above object is a group of electrodes in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and at least one of the electrodes located on the outermost side is a negative electrode, The negative electrode has a main body portion and a current collecting tab portion that protrudes from the main body portion in a plan view and is narrower than the main body portion. The negative electrode other than the outermost negative electrode has a negative electrode mixture layer formed on both surfaces of the main body, and the current collector tab has no negative electrode mixture layer formed on the current collector. The two negative electrodes located on the outermost side of the electrode group have a negative electrode mixture layer formed only on the surface of the main body portion opposite to the outermost side of the electrode group, and the electrode on the main body portion. On the outermost surface of the group and the current collecting tab portion, the negative electrode mixture layer is not formed on the current collector. The outer peripheral portion of the body, and is characterized in that over at least a portion of the end surface of the negative electrode mixture layer.
本発明によれば、高い信頼性を有し、生産性が良好な電池を提供することができる。 According to the present invention, a battery having high reliability and good productivity can be provided.
図1に、本発明の電池の一例の縦断面図を模式的に示す。図1に示す電池は、電池ケースを構成する外装ケース2と封口ケース3とが、絶縁ガスケット4を介してカシメ封口されて形成された空間内に、電極群および電解液が収容された構造の電池、すなわち、扁平形電池の例である。 In FIG. 1, the longitudinal cross-sectional view of an example of the battery of this invention is typically shown. The battery shown in FIG. 1 has a structure in which an electrode group and an electrolytic solution are accommodated in a space formed by caulking and sealing an exterior case 2 and a sealing case 3 constituting a battery case via an insulating gasket 4. It is an example of a battery, that is, a flat battery.
なお、電池業界においては、高さより径の方が大きい扁平形電池をコイン形電池と呼んだり、ボタン形電池と呼んだりしているが、そのコイン形電池とボタン形電池との間に明確な差はなく、本明細書でいう扁平形電池には、コイン形電池、ボタン形電池のいずれもが含まれる。 In the battery industry, a flat battery with a diameter larger than the height is called a coin-type battery or a button-type battery, but there is a clear gap between the coin-type battery and the button-type battery. There is no difference, and the flat battery referred to in this specification includes both coin-type batteries and button-type batteries.
図1に示す電池は、正極5および負極6を、セパレータ7を介して、それらの平面が電池の扁平面に略平行(平行を含む)となるように積層した積層型の電極群と、電解液(図示しない)とが、外装ケース2、封口ケース3および絶縁ガスケット4により形成される空間(密閉空間)内に収容されている。封口ケース3は、外装ケース2の開口部に絶縁ガスケット4を介して嵌合しており、外装ケース2の開口端部が内方に締め付けられ、これにより絶縁ガスケット4が封口ケース3に当接することで、外装ケース2の開口部が封口されて電池内部が密閉構造となっている。外装ケース2および封口ケース3は、ステンレス鋼などの金属製であり、絶縁ガスケット4は、ナイロンなどの絶縁性を有する樹脂製である。 The battery shown in FIG. 1 includes a positive electrode 5 and a negative electrode 6 stacked via a separator 7 so that their planes are substantially parallel (including parallel) to the flat surface of the battery, Liquid (not shown) is contained in a space (sealed space) formed by the outer case 2, the sealing case 3, and the insulating gasket 4. The sealing case 3 is fitted to the opening of the outer case 2 via an insulating gasket 4, and the opening end of the outer case 2 is tightened inward, whereby the insulating gasket 4 contacts the sealing case 3. Thereby, the opening part of the exterior case 2 is sealed, and the inside of the battery has a sealed structure. The outer case 2 and the sealing case 3 are made of a metal such as stainless steel, and the insulating gasket 4 is made of an insulating resin such as nylon.
図2に負極6の平面図を模式的に示しているが、負極6は、本体部6aと、平面視で、本体部6aから突出した、本体部6aよりも幅(図2中上下方向の長さ)の狭い集電タブ部6bとを有している。 FIG. 2 schematically shows a plan view of the negative electrode 6. The negative electrode 6 has a main body 6a and a width larger than that of the main body 6a projecting from the main body 6a in plan view (in the vertical direction in FIG. 2). And a current collecting tab portion 6b having a narrow length.
図1に示す電池1では、電極群の最外部側に位置する負極6Bの本体部6aでは、集電体62の片面(電池内側の面)にのみ、負極活物質やバインダなどを含有する負極合剤層61が形成されており、それ以外の負極6Aの本体部6aでは、集電体62の両面に負極合剤層が形成されている。更に、負極6A、6Bの集電タブ部6bでは、集電体62表面に負極合剤層61が形成されておらず、集電体が露出している。そして、図1に示す電池では、電極群における図中上側の負極6Bの集電体62の露出面が、封口ケース3の内面と溶接されるか、または溶接されずに直接接することで、電気的に接続している。すなわち、図1に示す電池では、封口ケース3は負極端子を兼ねている。 In the battery 1 shown in FIG. 1, in the main body 6a of the negative electrode 6B located on the outermost side of the electrode group, a negative electrode containing a negative electrode active material, a binder, or the like only on one surface of the current collector 62 (surface inside the battery). The mixture layer 61 is formed, and the negative electrode mixture layer is formed on both surfaces of the current collector 62 in the other main body portion 6a of the negative electrode 6A. Further, in the current collecting tab portion 6b of the negative electrodes 6A and 6B, the negative electrode mixture layer 61 is not formed on the surface of the current collector 62, and the current collector is exposed. In the battery shown in FIG. 1, the exposed surface of the current collector 62 of the upper negative electrode 6 </ b> B in the electrode group is welded to the inner surface of the sealing case 3 or is directly contacted without being welded. Connected. That is, in the battery shown in FIG. 1, the sealing case 3 also serves as a negative electrode terminal.
そして、電極群の有する全ての負極6(集電体62の両面に負極剤層61が形成された負極6Aおよび集電体62の片面に負極剤層61が形成された負極6B)は、それらの集電タブ部6bを介して互いに電気的に接続している。なお、各負極6の集電タブ部6bの接続は、例えば溶接により行うことができる。 And all the negative electrodes 6 (the negative electrode 6A in which the negative electrode agent layer 61 is formed on both surfaces of the current collector 62 and the negative electrode 6B in which the negative electrode agent layer 61 is formed on one surface of the current collector 62) included in the electrode group, Are electrically connected to each other through the current collecting tab portion 6b. In addition, the connection of the current collection tab part 6b of each negative electrode 6 can be performed by welding, for example.
また、図1に示す電池では、各正極5の集電タブ部5bが互いに電気的に接続され、かつ外装ケース2の内面と溶接されるか、または溶接されずに直接接することで、電気的に接続している。すなわち、図1に示す電池では、外装ケース2は正極端子を兼ねている。なお、図1に示す電池では、電極群の最下部に位置する負極6Bと、正極端子を兼ねる外装ケース2とを絶縁する目的で、これらの間にポリエチレンテレフタレート(PET)やポリイミドなどで形成されたテープなどからなる絶縁シール8が配置されている。 Further, in the battery shown in FIG. 1, the current collecting tab portions 5b of the respective positive electrodes 5 are electrically connected to each other and welded to the inner surface of the outer case 2 or directly contacted without being welded. Connected to. That is, in the battery shown in FIG. 1, the outer case 2 also serves as a positive electrode terminal. The battery shown in FIG. 1 is formed of polyethylene terephthalate (PET), polyimide, or the like between them for the purpose of insulating the negative electrode 6B located at the bottom of the electrode group from the outer case 2 that also serves as the positive electrode terminal. An insulating seal 8 made of a tape or the like is disposed.
図3に負極6Aの要部(本体部6a)の断面の拡大図を模式的に示している。集電体62の片面にのみ負極合剤層61を有する負極6Aの本体部6aでは、図3に示すように、集電体62の外周部が、負極合剤層61の端面(図中左端の面)の少なくとも一部を覆っている。 FIG. 3 schematically shows an enlarged view of a cross section of the main part (main body part 6a) of the negative electrode 6A. In the main body portion 6a of the negative electrode 6A having the negative electrode mixture layer 61 only on one side of the current collector 62, the outer peripheral portion of the current collector 62 is the end surface of the negative electrode mixture layer 61 (the left end in the figure) as shown in FIG. Covers at least part of the surface.
負極を作製するにあたっては、例えば、一旦幅広の負極を作製し、これをポンチおよびダイスを用いて打ち抜く方法が採用されるが、この場合、ポンチとダイスとのクリアランスによっては、切断し難く伸びやすい集電体の外周部が、切断しやすい負極合剤層の外縁から突出した形でバリとして残りやすい。 In producing the negative electrode, for example, a method of once producing a wide negative electrode and punching it out using a punch and a die is employed. In this case, depending on the clearance between the punch and the die, it is difficult to cut and easily stretches. The outer peripheral portion of the current collector tends to remain as burrs in a form protruding from the outer edge of the negative electrode mixture layer that is easily cut.
そこで、本発明では、積層型の電極群が使用される電池における負極のなかでも、特に負極合剤層からの微小片の脱落が生じやすい電極群の最外部側に配置される2枚の負極(すなわち、集電体の電池内側の面にのみ負極合剤層を有する負極。図1における負極6B。)において、打ち抜き時に発生しやすいバリによって負極合剤層の端面を覆うことで、負極合剤層からの微小片の脱落を抑えて、例えば、負極において負極合剤層の規定量を満たし得るようにし、容量低下を抑制したり、脱落した微小片によるトラブルの発生を防止したりするなどして、電池の信頼性および生産性を高めている。 Therefore, in the present invention, two negative electrodes disposed on the outermost side of the electrode group in which minute pieces are likely to fall off from the negative electrode mixture layer, among negative electrodes in a battery in which a stacked electrode group is used. (That is, a negative electrode having a negative electrode mixture layer only on the inner surface of the current collector. Negative electrode 6B in FIG. 1). By covering the end surface of the negative electrode mixture layer with burrs that are likely to occur during punching, the negative electrode mixture layer is covered. Suppressing detachment of fine pieces from the agent layer, for example, so that the specified amount of the negative electrode mixture layer can be satisfied in the negative electrode, suppressing a decrease in capacity, preventing troubles caused by the detached fine pieces, etc. This increases the reliability and productivity of the battery.
また、図1に示すように、金属製の外装ケースおよび封口ケースを有する電池では、外装ケースまたは封口ケースのいずれか一方が正極端子を、他方が負極端子を兼ねている。例えば図1に示すように、電極群の最外部側の2枚の電極はいずれも負極にした場合には、正極端子を兼ねる外装ケースまたは封口ケースと、これらのうちの一方の負極とは距離が非常に近く、この負極にバリが生じていると、正極端子を兼ねるケースと電極群の最外部側の負極のバリとが接触する虞がある。 As shown in FIG. 1, in a battery having a metal outer case and a sealing case, either the outer case or the sealing case serves as a positive electrode terminal and the other serves as a negative electrode terminal. For example, as shown in FIG. 1, when the two electrodes on the outermost side of the electrode group are both negative electrodes, the distance between the outer case or sealing case that also serves as the positive electrode terminal and one of these negative electrodes If the negative electrode has burrs, the case that also serves as the positive electrode terminal and the negative electrode burrs on the outermost side of the electrode group may come into contact with each other.
しかしながら、本発明の電池では、電極群の最外部側の負極においては、前記のバリによって集電体の電池内側の面に形成された負極合剤層の端面の少なくとも一部を覆う。そのため、電極群の最外部側の2枚の電極をいずれも負極にした場合には、正極端子を兼ねるケースにより近い負極においては、そのバリの向きが、正極端子を兼ねるケースとは反対側の方向を向いている。よって、本発明の電池において、電極群の最外部側の2枚の電極をいずれも負極とした場合には、正極端子を兼ねる外装ケースまたは封口ケースと、電極群の最外部側の負極のバリとの接触による短絡を抑制することができ、その信頼性を更に高めることができる。 However, in the battery of the present invention, in the negative electrode on the outermost side of the electrode group, at least a part of the end surface of the negative electrode mixture layer formed on the inner surface of the current collector is covered by the burrs. Therefore, when the two electrodes on the outermost side of the electrode group are both negative, in the negative electrode closer to the case that also serves as the positive electrode terminal, the direction of the burr is opposite to the case that also serves as the positive electrode terminal. Facing the direction. Therefore, in the battery of the present invention, when the two electrodes on the outermost side of the electrode group are both negative electrodes, the outer case or the sealing case that also serves as the positive electrode terminal and the variability of the negative electrode on the outermost side of the electrode group. Can be suppressed, and the reliability can be further improved.
電極群の最外部側に位置する負極における負極合剤層の端面では、その全面が集電体の外周部(バリ)により覆われていなくても、負極合剤層からの微小片の脱落を、ある程度抑制できる。具体的には、電極群の最外部側に位置する負極における負極合剤層の端面のうち、集電体の外周部により覆われている領域は、負極合剤層の厚みの30%以上であることが好ましく、これにより、負極合剤層からの微小片の脱落を良好に抑制することができる。電極群の最外周側に位置する負極における負極合剤層の端面のうち、集電体の外周部により覆われている領域は、負極合剤層の厚みの100%(すなわち、負極合剤層の端面の全面)であることが特に好ましい。 At the end face of the negative electrode mixture layer in the negative electrode located on the outermost side of the electrode group, even if the entire surface is not covered by the outer peripheral portion (burr) of the current collector, the fine pieces are removed from the negative electrode mixture layer. To some extent. Specifically, of the end face of the negative electrode mixture layer in the negative electrode located on the outermost side of the electrode group, the region covered by the outer periphery of the current collector is 30% or more of the thickness of the negative electrode mixture layer. It is preferable that it is possible, and thereby it is possible to satisfactorily suppress the dropping of the fine pieces from the negative electrode mixture layer. Of the end face of the negative electrode mixture layer in the negative electrode located on the outermost peripheral side of the electrode group, the region covered by the outer peripheral portion of the current collector is 100% of the thickness of the negative electrode mixture layer (that is, the negative electrode mixture layer) It is particularly preferable that the entire surface of the end face.
また、本発明の電池では、電極群の最外部側に位置する負極以外の負極(図1における負極6A)についても、負極合剤層の端面の少なくとも一部が集電体の外周部で覆われていることが好ましい。ただし、電極群の最外部側に位置する負極以外の負極は、前記の通り、集電体の両面に負極合剤層を有しているため、これらの負極合剤層のいずれか一方の端面の少なくとも一部が集電体の外周部で覆われていることが望ましい。 In the battery of the present invention, at least a part of the end surface of the negative electrode mixture layer is covered with the outer peripheral portion of the current collector also for the negative electrode other than the negative electrode located on the outermost side of the electrode group (negative electrode 6A in FIG. 1). It is preferable that However, since the negative electrode other than the negative electrode located on the outermost side of the electrode group has the negative electrode mixture layer on both surfaces of the current collector as described above, either one of the end surfaces of these negative electrode mixture layers It is desirable that at least a part of is covered with the outer periphery of the current collector.
なお、電極群の最外部側に位置する負極以外の負極においても、集電体の外周部で覆われている負極合剤層では、その覆われている領域は、それによる効果を良好に確保する観点から、負極合剤層の厚みの30%以上であることが好ましく、負極合剤層の厚みの100%であることが特に好ましい。 In addition, even in the negative electrode other than the negative electrode located on the outermost side of the electrode group, in the negative electrode mixture layer covered with the outer peripheral portion of the current collector, the covered region ensures a good effect due thereto. Therefore, the thickness is preferably 30% or more of the thickness of the negative electrode mixture layer, and particularly preferably 100% of the thickness of the negative electrode mixture layer.
負極における負極合剤層の端面の少なくとも一部を集電体の外周部で覆うには、例えば、幅広のシート状負極をポンチおよびダイスを用いて打ち抜いて本体部と集電タブ部とを有する負極とする際に、ポンチとダイスとのクリアランスを調整し、更に、端面を集電体の外周部で覆う負極合剤層を有する面側が、ポンチと接するようにして打ち抜く方法が採用できる。バリとして残る集電体の外周部は、ポンチの移動方向(以下、「打ち抜き方向」という)の反対方向に曲がりやすく、ポンチとダイスとのクリアランスを適切な距離に調整することで、バリの長さを適正な長さに調整しつつ、バリの向きを打ち抜き方向の反対方向に曲げて、負極合剤層の端面を良好に被覆することができる。 In order to cover at least a part of the end face of the negative electrode mixture layer in the negative electrode with the outer periphery of the current collector, for example, a wide sheet-like negative electrode is punched out using a punch and a die and has a main body part and a current collecting tab part When forming the negative electrode, a method of adjusting the clearance between the punch and the die and further punching the surface side having the negative electrode mixture layer covering the end surface with the outer peripheral portion of the current collector so as to be in contact with the punch can be employed. The outer periphery of the current collector remaining as burrs is easy to bend in the direction opposite to the punch movement direction (hereinafter referred to as the “punching direction”). By adjusting the clearance between the punch and the die to an appropriate distance, The end face of the negative electrode mixture layer can be satisfactorily covered by bending the burr direction in the direction opposite to the punching direction while adjusting the thickness to an appropriate length.
幅広の負極を打ち抜くためのポンチとダイスとのクリアランスは、負極の集電体の厚みの10〜65%とすることが好ましい。ポンチとダイスとのクリアランスが小さすぎると、集電体の外周部がバリとして残らなかったり、残っても短すぎて、負極合剤層の端面を良好に覆うことができない場合がある。また、ポンチとダイスとのクリアランスが大きすぎると、バリとして残る集電体の外周部が長くなりすぎて、負極合剤層の端面からはみ出す部分が生じ、正極の集電タブ部などと接触などする虞がある。 The clearance between the punch and the die for punching a wide negative electrode is preferably 10 to 65% of the thickness of the negative electrode current collector. If the clearance between the punch and the die is too small, the outer peripheral portion of the current collector may not remain as burrs or may be too short to cover the end face of the negative electrode mixture layer satisfactorily. Moreover, if the clearance between the punch and the die is too large, the outer peripheral portion of the current collector remaining as burrs becomes too long, resulting in a portion protruding from the end face of the negative electrode mixture layer, contact with the current collector tab portion of the positive electrode, etc. There is a risk of doing.
前記のシート状負極(幅広のシート状負極)は、例えば、負極活物質、バインダおよび必要に応じて導電助剤などを含む負極合剤を、溶剤に分散(バインダは溶解していてもよい)させて調製した負極合剤含有組成物(スラリー、ペーストなど)を、集電体の片面または両面に塗布し、乾燥する工程を経て作製することができる。シート状負極は、他の方法により作製してもよい。 The sheet-like negative electrode (wide sheet-like negative electrode) is, for example, a negative electrode mixture containing a negative electrode active material, a binder and, if necessary, a conductive auxiliary agent, dispersed in a solvent (the binder may be dissolved). The negative electrode mixture-containing composition (slurry, paste, etc.) prepared in such a manner can be produced by applying it on one or both sides of the current collector and drying it. The sheet-like negative electrode may be produced by other methods.
負極の本体部6aは、図2に示すように、平面視で、略円形であることが好ましいが、本発明の電池では、負極の本体部の平面視での面積が180mm2以下のように、小さなサイズの負極を有する場合(すなわち、小サイズの電池の場合)であっても、負極の打ち抜き時を始めとする電池製造時および電池の使用時における負極合剤層からの微小片の脱落を良好に抑制できる。なお、製造上の容易さを考慮すると、負極の本体部の平面視での面積は、20mm2以上であることが好ましい。 As shown in FIG. 2, the negative electrode body 6a is preferably substantially circular in plan view. However, in the battery of the present invention, the area of the negative electrode body in plan view is 180 mm 2 or less. Even when having a small-sized negative electrode (that is, in the case of a small-sized battery), the detachment of small pieces from the negative electrode mixture layer at the time of manufacturing the battery, including when the negative electrode is punched, and during use of the battery Can be suppressed satisfactorily. In view of ease of manufacturing, the area of the negative electrode main body in plan view is preferably 20 mm 2 or more.
図4には、正極5の平面図を模式的に示している。正極5は、図4に示すように、本体部5aと、平面視で、本体部5aから突出した集電タブ部5bとを有するものとすることができる。集電タブ部5bは、通常、図4に示すように、その幅(図4中上下方向の長さ)を本体部5aの幅よりも狭くする。 FIG. 4 schematically shows a plan view of the positive electrode 5. As shown in FIG. 4, the positive electrode 5 can include a main body portion 5 a and a current collecting tab portion 5 b protruding from the main body portion 5 a in plan view. As shown in FIG. 4, the current collecting tab portion 5b usually has a width (length in the vertical direction in FIG. 4) narrower than that of the main body portion 5a.
図1に示す電池1では、正極5の本体部5aは、集電体52の両面に、正極合剤層51が形成されている。そして、正極5の集電タブ部5bは、集電体52表面に正極合剤層51が形成されておらず、集電体52が露出している。なお、図1に示す電池1に係る電極群では、最外部(図中上下両端)の電極がいずれも負極(負極6B)であり、正極5は、全てが両側(両面)でセパレータ7を介して負極6と対向しているために、集電体52の両面に正極合剤層51を有している。 In the battery 1 shown in FIG. 1, the body portion 5 a of the positive electrode 5 has a positive electrode mixture layer 51 formed on both surfaces of a current collector 52. In the current collecting tab portion 5 b of the positive electrode 5, the positive electrode mixture layer 51 is not formed on the surface of the current collector 52, and the current collector 52 is exposed. In the electrode group according to the battery 1 shown in FIG. 1, the outermost electrodes (upper and lower ends in the figure) are all negative electrodes (negative electrode 6B), and the positive electrodes 5 are all on both sides (both sides) with separators 7 interposed therebetween. Therefore, the positive electrode mixture layer 51 is provided on both surfaces of the current collector 52.
なお、図1では、最外部側の2枚の電極がいずれも負極である電極群を用いた態様を示しているが、電極群の最外部側の電極の一方は正極であってもよく、その場合、最外部側の正極は、本体部における集電体の片面(電池内側の面)にのみ正極合剤層を有する構造であってもよい。 In addition, in FIG. 1, although the electrode group in which the two electrodes on the outermost side are both negative electrodes is shown, one of the outermost electrodes in the electrode group may be a positive electrode, In this case, the outermost positive electrode may have a structure in which the positive electrode mixture layer is provided only on one surface (surface inside the battery) of the current collector in the main body.
正極の製法については特に制限はないが、負極と同様の方法により作製することができる。すなわち、例えば、集電体の片面または両面の一部に正極合剤層を有するシート状正極(幅広のシート状正極)を、ポンチおよびダイスを用いて打ち抜き、本体部と集電タブ部とを有する正極を作製することができる。また、前記のシート状正極は、例えば、正極活物質、導電助剤、およびバインダなどを含む正極合剤を、溶剤に分散(バインダは溶解していてもよい)させて調製した正極合剤含有組成物(スラリー、ペーストなど)を、集電体の両面に塗布し、乾燥する工程を経て作製することができる。シート状正極は、他の方法により作製してもよい。 Although there is no restriction | limiting in particular about the manufacturing method of a positive electrode, It can produce by the method similar to a negative electrode. That is, for example, a sheet-like positive electrode (wide sheet-like positive electrode) having a positive electrode mixture layer on one side or a part of both sides of a current collector is punched using a punch and a die, and a main body portion and a current collecting tab portion are formed. The positive electrode which has can be produced. The sheet-like positive electrode contains, for example, a positive electrode mixture prepared by dispersing a positive electrode mixture containing a positive electrode active material, a conductive additive, and a binder in a solvent (the binder may be dissolved). A composition (slurry, paste, etc.) can be produced through a process of applying the composition on both sides of a current collector and drying it. The sheet-like positive electrode may be produced by other methods.
図5および図6に、本発明の電池の他の例を模式的に示す。図5および図6に示す電池1は、正極5(両側が負極6と対向している正極5)の両面に配置された2枚のセパレータ7、7の周縁部に接合部を形成して構成した電極群を有するものであり、図5は、電池の電池ケース(外装ケース2および封口ケース3)および絶縁ガスケット4部分の断面を表す縦断面図であり、図6は図5の要部を拡大し、更に電極群の部分を断面にしたものである。 5 and 6 schematically show another example of the battery of the present invention. The battery 1 shown in FIG. 5 and FIG. 6 is configured by forming joints at the peripheral portions of the two separators 7 and 7 arranged on both sides of the positive electrode 5 (the positive electrode 5 facing both sides of the negative electrode 6). FIG. 5 is a longitudinal sectional view showing a cross section of the battery case (the outer case 2 and the sealing case 3) and the insulating gasket 4 of the battery, and FIG. 6 shows the main part of FIG. This is an enlarged view of the electrode group.
なお、図5では、電極群の最外部側の2枚の負極6B、6Bの負極合剤層の手前側側面全面および左側面全面が、負極集電体61の外周部(バリ)により覆われており、かつ電極群の最外部側の負極6B、6B以外の負極6Aの負極合剤層のうち、図中下側の負極合剤層の手前側側面全面および左側面全面が、負極集電体61の外周部により覆われている様子を示している。 In FIG. 5, the entire front side surface and the entire left side surface of the negative electrode mixture layer of the two negative electrodes 6B and 6B on the outermost side of the electrode group are covered with the outer peripheral portion (burr) of the negative electrode current collector 61. In addition, among the negative electrode mixture layers of the negative electrode 6A other than the negative electrodes 6B and 6B on the outermost side of the electrode group, the entire front side surface and the entire left side surface of the lower negative electrode mixture layer in the drawing are negative electrode current collectors. A state in which the outer periphery of the body 61 is covered is shown.
また、図7に、周縁部の一部に接合部を形成したセパレータの平面図を模式的に示す。なお、図7では、セパレータ7とともに、正極、負極およびセパレータが積層された積層型の電極群とした場合を想定して、セパレータ7の下に配置される正極5を点線で示し、それらの更に下側に配置される負極に係る集電タブ部6bを一点鎖線で示し、電極群に係る各構成要素の位置ずれを抑えるための結束テープ9を二点鎖線で示している。また、図7に示す正極5は、電極群において、その両側(両面)が負極と対向するものであり、図7では図示していないが、電極群とした場合、セパレータ7の上側(図中手前方向)には、少なくとも負極が配置される。 Moreover, the top view of the separator which formed the junction part in FIG. 7 in a part of peripheral part is shown typically. In FIG. 7, assuming the case of a stacked electrode group in which the positive electrode, the negative electrode, and the separator are stacked together with the separator 7, the positive electrode 5 disposed under the separator 7 is indicated by a dotted line. A current collecting tab portion 6b related to the negative electrode disposed on the lower side is indicated by a one-dot chain line, and a binding tape 9 for suppressing positional deviation of each component related to the electrode group is indicated by a two-dot chain line. Moreover, the positive electrode 5 shown in FIG. 7 is an electrode group in which both sides (both sides) are opposed to the negative electrode. Although not shown in FIG. In the forward direction), at least a negative electrode is arranged.
図7に示すセパレータ7は、正極5(図中点線で表示)を介してその下側(図中奥行き方向)に配置される他のセパレータと、その周縁部において互いに溶着した接合部7c(図中、格子模様で表示)を有している。すなわち、セパレータ7と、その下側に配置されたセパレータとは、周縁部で互いに溶着されて袋状となっており、その内部に正極5を収容している。 The separator 7 shown in FIG. 7 is joined to another separator disposed on the lower side (depth direction in the drawing) via the positive electrode 5 (indicated by a dotted line in the drawing), and a joint portion 7 c (FIG. Middle). That is, the separator 7 and the separator disposed below the separator 7 are welded to each other at the peripheral edge to form a bag shape, and the positive electrode 5 is accommodated therein.
なお、図7に示すセパレータ7は、正極5の本体部5a全面を覆う主体部7a(すなわち、正極5の本体部5aよりも平面視での面積が大きな主体部7a)と、主体部7aから突出し、正極5の集電タブ部5bの、本体部5aとの境界部を少なくとも含む部分を覆う張り出し部7bとを有している。そして、セパレータ7の主体部7aの周縁部の少なくとも一部に、正極5の両面に配置された2枚のセパレータ(セパレータ7と、正極5の下側に配置されたセパレータ)同士を互いに溶着した接合部7cを設けている。 7 includes a main body portion 7a (that is, a main body portion 7a having a larger area in plan view than the main body portion 5a of the positive electrode 5) and the main body portion 7a. It has a protruding portion 7b that protrudes and covers at least a portion of the current collecting tab portion 5b of the positive electrode 5 that includes a boundary portion with the main body portion 5a. Then, two separators (the separator 7 and the separator disposed below the positive electrode 5) disposed on both surfaces of the positive electrode 5 were welded to at least a part of the peripheral portion of the main body portion 7 a of the separator 7. A joint 7c is provided.
電池のセパレータには、高温下で熱収縮しやすい熱可塑性樹脂製の微多孔膜が使用されることが一般的であるが、このように、正極の両面に配置された2枚のセパレータにおいて、その周縁部を互いに溶着して接合部を形成することで、例えば、電池内が高温となっても、セパレータの熱収縮が抑制されるため、より安全性の高い電池を構成することができる。 In general, a microporous membrane made of a thermoplastic resin that is easily heat-shrinkable at a high temperature is used as a battery separator. Thus, in the two separators arranged on both sides of the positive electrode, By welding the peripheral portions to each other to form a joint portion, for example, even when the inside of the battery becomes high temperature, thermal contraction of the separator is suppressed, so that a battery with higher safety can be configured.
なお、図7に示すように、主体部と張り出し部とを有するセパレータを使用する場合、正極の両面に配置された2枚のセパレータを接合するための接合部は、セパレータの主体部の周縁部に設ければよいが、セパレータの張り出し部の周縁部(セパレータの張り出し部の周縁部のうち、主体部からの突出方向に沿う部分)にも接合部を設けてもよい。 In addition, as shown in FIG. 7, when using the separator which has a main-body part and an overhang | projection part, the junction part for joining the two separators arrange | positioned on both surfaces of a positive electrode is a peripheral part of the main part of a separator However, a joining portion may also be provided at the peripheral portion of the separator overhanging portion (the portion of the peripheral edge portion of the separator overhanging portion along the protruding direction from the main body portion).
接合部は、2枚のセパレータの周縁部同士を直接溶着して形成してもよいが、2枚のセパレータの間に熱可塑性樹脂で構成される層を介在させ、この層を介して2枚のセパレータを溶着することにより形成してもよい。ただし、後者の場合、セパレータ間に介在させる層を構成する熱可塑性樹脂の種類と、セパレータを構成する熱可塑性樹脂の種類によっては、接合部の強度が小さくなる場合があるため、セパレータ間に介在させる層は、セパレータを構成する熱可塑性樹脂と同種の樹脂で構成されたものを使用することが好ましい。すなわち、セパレータ同士を直接溶着したり、セパレータを構成する熱可塑性樹脂と同種の樹脂で構成される層を介してセパレータ同士を溶着したりした場合には、接合部の強度がセパレータ自身の強度とほぼ同等となるため、例えば、電池の使用時に振動などによって生じる虞のある接合部での剥離が良好に抑制でき、更に信頼性の高い電池とすることができる。 The joining portion may be formed by directly welding the peripheral portions of the two separators, but a layer made of a thermoplastic resin is interposed between the two separators, and two sheets are interposed via this layer. The separator may be formed by welding. However, in the latter case, depending on the type of thermoplastic resin that constitutes the layer interposed between the separators and the type of thermoplastic resin that constitutes the separator, the strength of the joint may be reduced. It is preferable to use the layer made of the same kind of resin as the thermoplastic resin constituting the separator. That is, when the separators are welded directly, or when the separators are welded via a layer composed of the same type of resin as the thermoplastic resin that constitutes the separator, the strength of the joint is determined by the strength of the separator itself. Since they are almost the same, for example, separation at a joint portion that may occur due to vibration or the like when the battery is used can be satisfactorily suppressed, and a battery with higher reliability can be obtained.
なお、図7に示すように主体部と張り出し部とを有するセパレータを使用する場合、セパレータの主体部に係る周縁部は、全てが接合部となっていてもよいが、例えば、図7に示すように、周縁部の一部を、セパレータ同士を溶着せずに非溶着部7d、7dとして残してもよい。2枚のセパレータを溶着して袋状とした後に、その中に正極を収容したり、1枚のセパレータの上に正極を配置し、その正極の上に更にセパレータを配置して、セパレータの周縁部を溶着して袋状としたセパレータの中に正極を収容したりした場合、セパレータ内に空気が残留することがある。しかし、このような正極を用いて電池を製造する場合、外装ケースと封口ケースとをかしめる際に、前記の残留空気が、非溶着部7d、7dを通じてセパレータ外へ良好に排出されるため、セパレータ内の残留空気による問題(発電時の反応が不均一になって容量が低下するなどの問題)の発生を防止できる。 In addition, when using the separator which has a main-body part and an overhang | projection part as shown in FIG. 7, all the peripheral parts which concern on the main-body part of a separator may be a junction part, For example, it shows in FIG. Thus, you may leave a part of peripheral part as the non-welding parts 7d and 7d, without welding separators. After the two separators are welded to form a bag, the positive electrode is accommodated therein, the positive electrode is disposed on one separator, and the separator is further disposed on the positive electrode. When the positive electrode is housed in a separator that is welded to form a bag, air may remain in the separator. However, when manufacturing a battery using such a positive electrode, when the outer case and the sealing case are caulked, the residual air is well discharged outside the separator through the non-welded portions 7d and 7d. Occurrence of problems due to residual air in the separator (problems such as non-uniform reaction during power generation and reduced capacity) can be prevented.
セパレータの周縁部に非溶着部を設ける場合、電池の生産性の低下を抑える観点から、その個数は1〜5個程度とすることが好ましい。また、セパレータの周縁部に非溶着部を設ける場合、セパレータの主体部に係る非溶着部の外縁の長さが、セパレータの主体部に係る外縁の全長さ(張り出し部を除く外縁の全長さ)の15〜60%程度することが好ましい。すなわち、セパレータの主体部においては、その外縁の全長さのうちの40%以上(好ましくは70%以上)が接合部であることが好ましく、これにより、セパレータ同士の接合強度を良好に確保することができる。 When providing a non-welding part in the peripheral part of a separator, it is preferable that the number shall be about 1-5 from a viewpoint of suppressing the productivity fall of a battery. Moreover, when providing a non-welding part in the peripheral part of a separator, the length of the outer edge of the non-welding part related to the main part of the separator is the total length of the outer edge related to the main part of the separator (the total length of the outer edge excluding the overhanging part). Is preferably about 15 to 60%. That is, in the main part of the separator, it is preferable that 40% or more (preferably 70% or more) of the entire length of the outer edge is a joined part, thereby ensuring good joining strength between the separators. Can do.
2枚のセパレータの周縁部に接合部を形成するとともに、これらのセパレータの間に正極を収容するには、2枚のセパレータ同士を直接溶着して接合部を形成する場合では、例えば、1枚のセパレータ上に正極を重ね、更にその上にセパレータを重ねた後、これらのセパレータの周縁部を溶着する方法が採用できる。また、2枚のセパレータを重ね、これらの周縁部を溶着してセパレータ同士を接合し、その後、これらのセパレータ間に正極を挿入する方法を採用することもできる。 In order to form a joint part at the peripheral part of two separators and to accommodate a positive electrode between these separators, when two separators are directly welded together to form a joint part, for example, one sheet It is possible to employ a method in which the positive electrode is overlaid on the separator, the separator is further overlaid thereon, and then the peripheral portions of these separators are welded. It is also possible to adopt a method in which two separators are stacked, the peripheral portions thereof are welded to join the separators, and then the positive electrode is inserted between these separators.
一方、2枚のセパレータ同士の間にセパレータの構成樹脂と同種の樹脂で構成された層を介在させ、これらを溶着して接合部を形成する場合では、例えば、1枚のセパレータ上の接合部となることが予定される箇所に前記層となるフィルムを置き、かつこのセパレータ上に正極を配置し、更にその上にセパレータを重ねた後、これらのセパレータの周縁部を溶着する方法が採用できる。また、1枚のセパレータ上の接合部となることが予定されている箇所に前記層となるフィルムを置き、このセパレータとフィルムとを予め溶着しておき、その後、このセパレータに正極、セパレータの順に重ねて周縁部を溶着する方法や、2枚のセパレータの間に前記層となるフィルムを介在させて溶着して接合部を形成した後に、これらのセパレータ間に正極を挿入する方法を採用することもできる。 On the other hand, when a layer composed of the same kind of resin as the constituent resin of the separator is interposed between the two separators and these are welded to form a joint, for example, the joint on one separator It is possible to adopt a method in which a film to be the layer is placed at a place where the layer is expected to be placed, a positive electrode is disposed on the separator, and a separator is further stacked thereon, and then the peripheral portions of these separators are welded. . In addition, a film to be the layer is placed in a place where it is planned to become a joint portion on one separator, and the separator and the film are previously welded. Adopting a method of laminating the peripheral portion by overlapping, or a method of inserting a positive electrode between these separators after forming a joined portion by interposing a film serving as the layer between two separators. You can also.
セパレータの周縁部の溶着は、例えば、加熱プレスにより行うことができる。この場合、加熱温度は、セパレータを構成する熱可塑性樹脂の融点よりも高い温度であればよいが、例えば、融点より10〜50℃高い温度で行うことが好ましい。また、加熱プレスの時間については、良好に接合部が形成できれば特に制限はないが、通常は、1〜10秒程度とする。 For example, the peripheral edge of the separator can be welded by a hot press. In this case, the heating temperature may be a temperature higher than the melting point of the thermoplastic resin constituting the separator, but for example, the heating temperature is preferably 10 to 50 ° C. higher than the melting point. Moreover, about the time of a hot press, if a junction part can be formed satisfactorily, there will be no restriction | limiting, However, Usually, it shall be about 1 to 10 second.
本発明の電池に係る電極群は、図1や図5、図6に示すように、最外部側の電極(上下両端)の電極を負極としてもよく、前記の通り、最外部側の一方の電極のみを負極(他方を正極)としてもよい。 As shown in FIGS. 1, 5, and 6, the electrode group according to the battery of the present invention may have the outermost electrodes (upper and lower ends) as negative electrodes, and as described above, one of the outermost electrodes. Only the electrode may be a negative electrode (the other is a positive electrode).
そして、例えば、図1や図5、図6に示すように、電池容器に金属製の外装ケースと金属製の封口ケースとを使用する場合には、前記の通り、負極端子を兼ねる外装ケースまたは封口ケースの内面と前記負極に係る負極合剤層を持たない面(集電体の露出面)とを直接接触させたり溶接したりすることで、負極端子と電極群に係る負極との電気的接続に利用することができる。他方、電池容器に金属製の外装ケースと金属製の封口ケースとを使用し、電極群の最外部側の電極のうち、正極端子を兼ねる電池容器(例えば外装ケース)に近い側の電極を正極とした場合、この正極は、集電体の両面に正極合剤層を有し、集電タブ部のみで正極端子を兼ねる電池容器(例えば外装ケース)と接していてもよく、集電体の片面(電池内側となる面)のみに正極合剤層を有し、集電体の露出面が、正極端子を兼ねる電池容器(例えば外装ケース)の内面と溶接されるか、または溶接されずに直接接触することで、電気的に接続していてもよい。 For example, as shown in FIGS. 1, 5, and 6, when using a metal outer case and a metal sealing case for the battery container, as described above, the outer case serving also as the negative electrode terminal or By directly contacting or welding the inner surface of the sealing case and the surface (exposed surface of the current collector) that does not have the negative electrode mixture layer related to the negative electrode, electrical connection between the negative electrode terminal and the negative electrode related to the electrode group Can be used for connection. On the other hand, a metal outer case and a metal sealing case are used for the battery container, and among the outermost electrodes of the electrode group, the electrode near the battery container (for example, the outer case) that also serves as the positive electrode terminal is used as the positive electrode. In this case, the positive electrode may have a positive electrode mixture layer on both sides of the current collector, and may be in contact with a battery container (for example, an outer case) that also serves as a positive electrode terminal only at the current collecting tab portion. The positive electrode mixture layer is provided only on one side (the inner surface of the battery), and the exposed surface of the current collector is welded or not welded to the inner surface of a battery container (for example, an outer case) that also serves as the positive electrode terminal. It may be electrically connected by direct contact.
また、少なくとも両側が負極と対向している正極の両面にはセパレータを配置するが、電極群の最外部側に配置される正極、すなわち片側(片面)のみが負極と対向している正極については、その両面にセパレータを配置してもよく(更に、これらの2枚のセパレータに接合部を形成してもよい)、負極と対向する面にのみセパレータを配置しても構わない。 In addition, separators are disposed on both sides of the positive electrode at least on both sides facing the negative electrode, but the positive electrode disposed on the outermost side of the electrode group, that is, the positive electrode on which only one side (one side) is opposed to the negative electrode In addition, separators may be disposed on both surfaces thereof (joint portions may be formed on these two separators), or separators may be disposed only on the surface facing the negative electrode.
電極群においては、各正極の集電タブ部が、電極群の平面視で同一方向を向くように配置されており、かつ各負極の集電タブ部が、電極群の平面視で同一方向を向くように配置されていることが好ましい。これにより、正極および負極の集電がより容易となる。 In the electrode group, the current collecting tab portion of each positive electrode is arranged so as to face the same direction in a plan view of the electrode group, and the current collecting tab portion of each negative electrode has the same direction in the plan view of the electrode group. It is preferable to arrange so as to face. Thereby, current collection of the positive electrode and the negative electrode becomes easier.
更に、各正極の集電タブ部と、各負極の集電タブ部とは、電極群の平面視で互いに接触しないように配置されていればよいが、これらの接触をより良好に抑制し、かつ電池の生産をより良好にする観点からは、図4に示しているように、各正極の集電タブ部5bと各負極の集電タブ部6bとは、電極群の平面視で互いに対向する位置に配されていることがより好ましい。 Furthermore, the current collecting tab portion of each positive electrode and the current collecting tab portion of each negative electrode only need to be arranged so as not to contact each other in a plan view of the electrode group, but these contacts are better suppressed, And from the viewpoint of making the production of the battery better, as shown in FIG. 4, the current collecting tab portion 5b of each positive electrode and the current collecting tab portion 6b of each negative electrode face each other in a plan view of the electrode group. More preferably, it is arranged at a position where
また、正極、負極およびセパレータを積層して構成した電極群は、図7に示すように、その外周を、耐薬品性を有するポリプロピレンなどで構成された結束テープ9で結束して、各構成要素(セパレータに包まれた正極、および負極)の位置ずれを抑制することが好ましい。 In addition, as shown in FIG. 7, the electrode group formed by laminating the positive electrode, the negative electrode, and the separator is bound to the outer periphery with a binding tape 9 made of polypropylene having chemical resistance, and each component. It is preferable to suppress misalignment of the positive electrode and the negative electrode wrapped in the separator.
電極群に係る正極および負極は、いずれも複数であり、電極の合計層数は、少なくとも4層であるが、それ以上(5層、6層、7層、8層など)とすることも可能である。ただし、正極および負極の積層数をあまり多くすると、扁平状電池としてのメリットが小さくなる虞があることから、通常は、40層以下とすることが好ましい。 There are a plurality of positive electrodes and negative electrodes in the electrode group, and the total number of layers of the electrode is at least 4, but it is also possible to make it more (5 layers, 6 layers, 7 layers, 8 layers, etc.) It is. However, if the number of stacked positive and negative electrodes is increased too much, the merit as a flat battery may be reduced. Therefore, it is usually preferable to have 40 layers or less.
図1、図5および図6では、外装ケースと封口ケースとが絶縁ガスケットを介してカシメ封口される形式の電池容器を示しているが、この他にも、例えば、金属ラミネートフィルムにより構成されるラミネートフィルム外装体や、外装ケースと封口ケースとを溶接する形式の電池容器を用いることもできる。 1, 5, and 6 show a battery container of a type in which an outer case and a sealing case are caulked and sealed through an insulating gasket, but in addition to this, for example, a metal laminate film is used. A laminate film outer package or a battery container of a type in which the outer case and the sealing case are welded can also be used.
なお、各正極の集電タブ部と電池の正極端子(例えば、正極端子を兼ねる外装ケースまたは封口ケース)との電気的接続、および各負極の集電タブ部と電池の負極端子(例えば、負極端子を兼ねる外装ケースまたは封口ケース)との電気的接続には、正極や負極とは別体のリード体(金属箔などで構成されたリード体)を介して行ってもよい。 It should be noted that the current collecting tab portion of each positive electrode and the battery positive electrode terminal (for example, an exterior case or sealing case that also serves as the positive electrode terminal) are electrically connected, and the current collecting tab portion of each negative electrode and the negative electrode terminal of the battery (for example, negative electrode) The electrical connection with the outer case or the sealing case that also serves as a terminal may be made via a lead body (lead body made of metal foil or the like) that is separate from the positive electrode and the negative electrode.
電池の平面形状には特に制限はなく、例えば扁平形電池の場合、従来から知られている扁平形電池の主流である円形の他、角形(四角形)などの多角形状でもよい。なお、本明細書でいう電池の平面形状としての角形などの多角形には、その角が切り落とされた形状や、角を曲線にした形状も包含される。また、正極および負極の本体部の平面形状は、電池の平面形状に応じた形状とすればよく、略円形とする他、長方形や正方形などの四角形などの多角形とすることもできるが、例えば、略円形とする場合には、対極の集電タブ部が配置される箇所に相当する部分は、対極の集電タブ部との接触を防止するために、図2および図3に示すように切り落とした形状としておくことが好ましい。 The planar shape of the battery is not particularly limited. For example, in the case of a flat battery, a polygonal shape such as a square (quadrangle) may be used in addition to a circular shape that is the mainstream of conventionally known flat batteries. In addition, the polygon such as a square as the planar shape of the battery in this specification includes a shape in which the corner is cut off and a shape in which the corner is curved. Moreover, the planar shape of the main body part of the positive electrode and the negative electrode may be a shape corresponding to the planar shape of the battery, and in addition to being substantially circular, it may be a polygon such as a rectangle such as a rectangle or a square. In the case of a substantially circular shape, the portion corresponding to the location where the current collecting tab portion of the counter electrode is disposed is shown in FIGS. 2 and 3 in order to prevent contact with the current collecting tab portion of the counter electrode. It is preferable that the shape is cut off.
図1や図5、図6では、外装ケースを正極ケースとし、封口ケースを負極ケースとした例を示したが、本発明の電池はこれに限定されず、必要に応じて、外装ケースを負極ケースとし、封口ケースを正極ケースとすることもできる。 1, 5, and 6 show examples in which the outer case is a positive electrode case and the sealing case is a negative electrode case, but the battery of the present invention is not limited to this, and the outer case may be a negative electrode as necessary. A case and a sealing case can be used as a positive electrode case.
本発明の電池は、その種類について特に制限はなく、例えば、非水一次電池(リチウムイオン一次電池など)や非水二次電池(リチウムイオン二次電池など)が含まれる。以下には、本発明の電池のうち、特に主要な態様である非水二次電池の場合について、詳細に説明する。 The type of the battery of the present invention is not particularly limited, and examples thereof include a non-aqueous primary battery (such as a lithium ion primary battery) and a non-aqueous secondary battery (such as a lithium ion secondary battery). Below, the case of the non-aqueous secondary battery which is a main aspect among the batteries of this invention is demonstrated in detail.
正極活物質としては、例えば、LixCoO2、LixNiO2、LixMnO2、LixCoyNi1−yO2、LixCoyM1−yO2、LixNi1−yMyO2、LixMnyNizCo1−y−zO2、LixMn2O4、LixMn2−yMyO4などのリチウム遷移金属複合酸化物などが挙げられる(ただし、前記の各リチウム遷移金属複合酸化物において、Mは、Mg、Mn、Fe、Co、Ni、Cu、Zn、AlおよびCrからなる群から選ばれる少なくとも1種の金属元素であり、0≦x≦1.1、0<y<1.0、2.0≦z≦2.2である。)。これらの正極活物質は1種単独で使用してもよく、2種以上を併用しても構わない。 Examples of the positive electrode active material include Li x CoO 2 , Li x NiO 2 , Li x MnO 2 , Li x Co y Ni 1-y O 2 , Li x Co y M 1-y O 2 , and Li x Ni 1-1. like y M y O 2, Li x Mn y Ni z Co 1-y-z O 2, Li x Mn 2 O 4, Li x Mn 2-y M y O 4 lithium-transition metal composite oxides such as (However, in each of the lithium transition metal composite oxides, M is at least one metal element selected from the group consisting of Mg, Mn, Fe, Co, Ni, Cu, Zn, Al, and Cr; ≦ x ≦ 1.1, 0 <y <1.0, 2.0 ≦ z ≦ 2.2.) These positive electrode active materials may be used individually by 1 type, and may use 2 or more types together.
また、正極の導電助剤としては、例えば、カーボンブラック、鱗片状黒鉛、ケッチェンブラック、アセチレンブラック、繊維状炭素などが挙げられる。更に、正極のバインダとしては、例えば、ポリテトラフルオロエチレン(PTFE)、ポリフッ化ビニリデン(PVDF)、カルボキシメチルセルロース(CMC)、スチレンブタジエンラバー(SBR)などが挙げられる。 Moreover, as a conductive support agent of a positive electrode, carbon black, scale-like graphite, ketjen black, acetylene black, fibrous carbon etc. are mentioned, for example. Furthermore, examples of the binder for the positive electrode include polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), carboxymethyl cellulose (CMC), and styrene butadiene rubber (SBR).
正極の組成としては、例えば、正極を構成する正極合剤100質量%中、正極活物質を75〜90質量%、導電助剤を5〜20質量%、バインダを3〜15質量%とすることが好ましい。また、正極合剤層の厚みは、例えば、30〜200μmであることが好ましい。 As a composition of the positive electrode, for example, in 100% by mass of the positive electrode mixture constituting the positive electrode, the positive electrode active material is 75 to 90% by mass, the conductive additive is 5 to 20% by mass, and the binder is 3 to 15% by mass. Is preferred. Moreover, it is preferable that the thickness of a positive mix layer is 30-200 micrometers, for example.
正極の集電体としては、アルミニウムやアルミニウム合金で構成された金属箔、エキスパンドメタル、平織り金網などが挙げられる。なお、正極の総厚みを小さくし、電池内における正極および負極の積層数を増やすことで正極合剤層と負極合剤層との対向面積を大きくして、電池の負荷特性を高める観点からは、集電体には金属箔を使用することが好ましい。また、集電体の厚みは、例えば、8〜20μmであることが好ましい。 Examples of the current collector for the positive electrode include a metal foil made of aluminum or an aluminum alloy, an expanded metal, and a plain weave wire mesh. From the viewpoint of increasing the load characteristics of the battery by reducing the total thickness of the positive electrode and increasing the number of layers of the positive electrode and negative electrode in the battery to increase the facing area between the positive electrode mixture layer and the negative electrode mixture layer. The current collector is preferably a metal foil. Moreover, it is preferable that the thickness of a collector is 8-20 micrometers, for example.
負極活物質としては、リチウム、リチウム合金、リチウムイオンを吸蔵放出可能な炭素材料、チタン酸リチウムなどが挙げられる。 Examples of the negative electrode active material include lithium, a lithium alloy, a carbon material capable of occluding and releasing lithium ions, and lithium titanate.
負極活物質に用い得るリチウム合金としては、例えば、リチウム−アルミニウム、リチウム−ガリウムなどのリチウムと可逆的に合金化するリチウム合金が挙げられ、リチウム含有量が、例えば1〜15原子%であることが好ましい。また、負極活物質に用い得る炭素材料としては、例えば、人造黒鉛、天然黒鉛、低結晶性カーボン、コークス、無煙炭などが挙げられる。 Examples of the lithium alloy that can be used for the negative electrode active material include lithium alloys that reversibly alloy with lithium, such as lithium-aluminum and lithium-gallium, and the lithium content is, for example, 1 to 15 atomic%. Is preferred. Examples of the carbon material that can be used for the negative electrode active material include artificial graphite, natural graphite, low crystalline carbon, coke, and anthracite.
負極活物質に用い得るチタン酸リチウムとしては、一般式LixTiyO4で表され、xとyがそれぞれ、0.8≦x≦1.4、1.6≦y≦2.2の化学量論数を持つチタン酸リチウムが好ましく、特にx=1.33、y=1.67の化学量論数を持つチタン酸リチウムが好ましい。前記一般式LixTiyO4で表されるチタン酸リチウムは、例えば、酸化チタンとリチウム化合物とを760〜1100℃で熱処理することによって得ることができる。前記酸化チタンとしては、アナターゼ型、ルチル型のいずれも使用可能であり、リチウム化合物としては、例えば、水酸化リチウム、炭酸リチウム、酸化リチウムなどが用いられる。 The lithium titanate that can be used for the negative electrode active material is represented by the general formula Li x Ti y O 4 , and x and y are 0.8 ≦ x ≦ 1.4 and 1.6 ≦ y ≦ 2.2, respectively. Lithium titanate having a stoichiometric number is preferable, and lithium titanate having a stoichiometric number of x = 1.33 and y = 1.67 is particularly preferable. The lithium titanate represented by the general formula Li x Ti y O 4 can be obtained, for example, by heat-treating titanium oxide and a lithium compound at 760 to 1100 ° C. As the titanium oxide, either anatase type or rutile type can be used, and examples of the lithium compound include lithium hydroxide, lithium carbonate, and lithium oxide.
負極に係るバインダおよび導電助剤としては、正極に用い得るものとして先に例示した各種バインダおよび導電助剤を用いることができる。ただし、負極合剤含有組成物に用いる溶剤は、環境保護などの観点から、その主成分が水であることが好ましいため、負極に係るバインダには、こうした負極合剤含有組成物の形成に適したもの、例えば、水を媒体とするエマルジョンや水溶液の状態で使用されるSBRやCMCなどが特に好ましい。なお、前記の通り、水系の溶剤を用いた負極合剤含有組成物に適したこれらのバインダは、例えば、正極用のバインダとして汎用されるPVDFなどに比べて結着力が小さいため、SBRやCMCをバインダとして使用した負極合剤層からは微小片が脱落しやすいが、本発明の電池に係る負極では、こうした結着力に劣るバインダを使用しても、負極合剤層からの微小片の脱落を良好に抑制できる。 As the binder and the conductive auxiliary agent related to the negative electrode, various binders and conductive auxiliary agents exemplified above as those that can be used for the positive electrode can be used. However, since the main component of the solvent used in the negative electrode mixture-containing composition is preferably water from the viewpoint of environmental protection, the binder for the negative electrode is suitable for forming such a negative electrode mixture-containing composition. Particularly preferred are, for example, SBR and CMC used in the form of an emulsion or aqueous solution using water as a medium. As described above, these binders suitable for the negative electrode mixture-containing composition using a water-based solvent have a smaller binding force than, for example, PVDF, which is widely used as a binder for positive electrodes, so SBR and CMC In the negative electrode according to the battery of the present invention, even if a binder having inferior binding force is used, the fine pieces are removed from the negative electrode mixture layer. Can be suppressed satisfactorily.
負極活物質に炭素材料を用いる場合の負極の組成としては、例えば、負極を構成する負極合剤100質量%中、炭素材料を80〜95質量%、バインダを3〜15質量%とすることが好ましく、また、導電助剤を併用する場合には、導電助剤を5〜20質量%とすることが好ましい。他方、負極活物質にチタン酸リチウムを用いる場合の負極の組成としては、例えば、負極を構成する負極合剤100質量%中、チタン酸リチウムを75〜90質量%、バインダを3〜15質量%とすることが好ましく、また、導電助剤を併用する場合には、導電助剤を5〜20質量%とすることが好ましい。 The composition of the negative electrode when a carbon material is used as the negative electrode active material is, for example, that the carbon material is 80 to 95% by mass and the binder is 3 to 15% by mass in 100% by mass of the negative electrode mixture constituting the negative electrode. Moreover, when using together a conductive support agent, it is preferable that a conductive support agent shall be 5-20 mass%. On the other hand, the composition of the negative electrode when lithium titanate is used as the negative electrode active material is, for example, 75 to 90% by mass of lithium titanate and 3 to 15% by mass of the binder in 100% by mass of the negative electrode mixture constituting the negative electrode. In addition, when a conductive auxiliary is used in combination, the conductive auxiliary is preferably 5 to 20% by mass.
負極における負極合剤層の厚みは、例えば、40〜200μmであることが好ましい。 The thickness of the negative electrode mixture layer in the negative electrode is preferably 40 to 200 μm, for example.
負極の集電体としては、銅や銅合金で構成された金属箔、エキスパンドメタル、平織り金網などが挙げられる。なお、負極の総厚みを小さくし、電池内における正極および負極の積層数を増やすことで正極合剤層と負極合剤層との対向面積を大きくして、電池の負荷特性を高める観点からは、集電体には金属箔を使用することが好ましい。また、集電体の厚みは、例えば、5〜30μmであることが好ましい。 Examples of the current collector for the negative electrode include a metal foil made of copper or a copper alloy, an expanded metal, and a plain weave wire mesh. From the viewpoint of improving the load characteristics of the battery by reducing the total thickness of the negative electrode and increasing the number of layers of the positive electrode and negative electrode in the battery to increase the facing area between the positive electrode mixture layer and the negative electrode mixture layer. The current collector is preferably a metal foil. Moreover, it is preferable that the thickness of a collector is 5-30 micrometers, for example.
セパレータには、熱可塑性樹脂製の微多孔膜で構成されたものを使用する。セパレータを構成する熱可塑性樹脂としては、例えば、ポリエチレン(PE)、ポリプロピレン(PP)、エチレン−プロピレン共重合体、ポリメチルペンテンなどのポリオレフィンが好ましく、セパレータ同士を溶着したり、セパレータ間にセパレータの構成樹脂と同種の樹脂を配置して溶着したりする観点からは、その融点、すなわち、JIS K 7121の規定に準じて、示差走査熱量計(DSC)を用いて測定される融解温度が、100〜180℃のポリオレフィンがより好ましい。 A separator made of a microporous film made of a thermoplastic resin is used. As the thermoplastic resin constituting the separator, for example, polyolefins such as polyethylene (PE), polypropylene (PP), ethylene-propylene copolymer, polymethylpentene, and the like are preferable. From the viewpoint of arranging and welding the same type of resin as the constituent resin, the melting point, that is, the melting temperature measured using a differential scanning calorimeter (DSC) in accordance with the provisions of JIS K 7121 is 100. A polyolefin of ˜180 ° C. is more preferable.
セパレータを構成する熱可塑性樹脂製の微多孔膜の形態としては、必要な電池特性が得られるだけのイオン伝導度を有していればどのような形態でもよいが、従来から知られている溶剤抽出法、乾式または湿式延伸法などにより形成された孔を多数有するイオン透過性の微多孔膜(電池のセパレータとして汎用されている微多孔フィルム)が好ましい。 The form of the microporous film made of the thermoplastic resin constituting the separator may be any form as long as it has an ionic conductivity sufficient to obtain the required battery characteristics, but is a conventionally known solvent. An ion-permeable microporous film (a microporous film that is widely used as a battery separator) having a large number of pores formed by an extraction method, a dry method or a wet stretching method is preferable.
セパレータの厚みは、例えば、5〜25μmであることが好ましく、また、空孔率は、例えば、30〜70%であることが好ましい。 The thickness of the separator is preferably, for example, 5 to 25 μm, and the porosity is preferably, for example, 30 to 70%.
電池に係る非水電解液としては、例えば、エチレンカーボネート(EC)、プロピレンカーボネート、ブチレンカーボネート、ビニレンカーボネートなどの環状炭酸エステル;ジメチルカーボネート、ジエチルカーボネート(DEC)、メチルエチルカーボネートなどの鎖状炭酸エステル;1,2−ジメトキシエタン、ジグライム(ジエチレングリコールメチルエーテル)、トリグライム(トリエチレングリコールジメチルエーテル)、テトラグライム(テトラエチレングリコールジメチルエーテル)、1,2−ジメトキシエタン、1,2−ジエトキシメタン、テトラヒドロフランなどのエーテル;などの有機溶媒に、電解質(リチウム塩)を0.3〜2.0mol/L程度の濃度に溶解させることによって調製した電解液を用いることができる。前記の有機溶媒は、それぞれ1種単独で用いてもよく、2種以上を併用しても構わない。 Examples of non-aqueous electrolytes for batteries include cyclic carbonates such as ethylene carbonate (EC), propylene carbonate, butylene carbonate, and vinylene carbonate; chain carbonate esters such as dimethyl carbonate, diethyl carbonate (DEC), and methyl ethyl carbonate. 1,2-dimethoxyethane, diglyme (diethylene glycol methyl ether), triglyme (triethylene glycol dimethyl ether), tetraglyme (tetraethylene glycol dimethyl ether), 1,2-dimethoxyethane, 1,2-diethoxymethane, tetrahydrofuran, etc. It is possible to use an electrolytic solution prepared by dissolving an electrolyte (lithium salt) in a concentration of about 0.3 to 2.0 mol / L in an organic solvent such as ether; That. The above organic solvents may be used alone or in combination of two or more.
前記電解質としては、例えば、LiBF4、LiPF6、LiAsF6、LiSbF6、LiClO4、LiCF3SO3、LiC4F9SO3、LiN(CF3SO2)2、LiN(C2F5SO2)2などのリチウム塩が挙げられる。 Examples of the electrolyte include LiBF 4 , LiPF 6 , LiAsF 6 , LiSbF 6 , LiClO 4 , LiCF 3 SO 3 , LiC 4 F 9 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) Lithium salts such as 2 are mentioned.
なお、図2に示す形状の負極と、図3に示す形状の正極と、図7に示す形状のセパレータとを使用し、図5および図6に示す構造の扁平形非水二次電池を製造したところ、信頼性に優れた扁平形非水二次電池を良好に生産することができた。また、この扁平形非水二次電池を分解したところ、負極合剤層からの微小片の脱落は認められなかった。 A flat non-aqueous secondary battery having the structure shown in FIGS. 5 and 6 is manufactured using the negative electrode having the shape shown in FIG. 2, the positive electrode having the shape shown in FIG. 3, and the separator having the shape shown in FIG. As a result, a flat non-aqueous secondary battery excellent in reliability was successfully produced. Further, when the flat non-aqueous secondary battery was disassembled, no minute pieces were removed from the negative electrode mixture layer.
本発明の電池は、非水一次電池や非水二次電池などの従来から知られている電池と同様の用途に適用することができる。 The battery of the present invention can be applied to the same applications as conventionally known batteries such as a non-aqueous primary battery and a non-aqueous secondary battery.
1 電池
2 外装ケース
3 封口ケース
4 絶縁ガスケット
5 正極
5a 正極の本体部
5b 正極の集電タブ部
6 負極
6a 負極の本体部
6b 負極の集電タブ部
7 セパレータ
7a セパレータの主体部
7b セパレータの張り出し部
7c 接合部
61 負極合剤層
62 負極集電体
DESCRIPTION OF SYMBOLS 1 Battery 2 Exterior case 3 Sealing case 4 Insulating gasket 5 Positive electrode 5a Positive electrode main body 5b Positive electrode current collecting tab 6 Negative electrode 6a Negative electrode main body 6b Negative current collecting tab 7 Separator 7a Separator main part 7b Separation of separator Part 7c Bonding part 61 Negative electrode mixture layer 62 Negative electrode current collector
Claims (9)
前記負極は、本体部と、平面視で、前記本体部から突出した、前記本体部よりも幅の狭い集電タブ部とを有しており、
電極群の最外部側の負極以外の負極には、その本体部の両面に負極合剤層が形成されており、その集電タブ部には、集電体に負極合剤層が形成されておらず、
電極群の最外部側に位置する負極には、その本体部における電極群の最外部側とは反対側の面にのみ負極合剤層が形成されており、その本体部における電極群の最外部側の面および集電タブ部には、集電体に負極合剤層が形成されておらず、集電体の外周部が、負極合剤層の端面の少なくとも一部を覆っていることを特徴とする電池。 A battery having an electrode group in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated via separators, and at least one of the electrodes located on the outermost side is a negative electrode, and an electrolyte solution,
The negative electrode has a main body part and a current collecting tab part that protrudes from the main body part in a plan view and is narrower than the main body part,
A negative electrode mixture layer is formed on both surfaces of the main body portion of the negative electrode other than the negative electrode on the outermost side of the electrode group, and a negative electrode mixture layer is formed on the current collector tab portion of the current collector. Not
In the negative electrode located on the outermost side of the electrode group, a negative electrode mixture layer is formed only on the surface of the main body portion opposite to the outermost side of the electrode group, and the outermost electrode group in the main body portion. The negative electrode mixture layer is not formed on the current collector on the side surface and the current collecting tab portion, and the outer peripheral portion of the current collector covers at least a part of the end surface of the negative electrode mixture layer. Battery characterized.
前記正極の本体部では、集電体の片面または両面に正極活物質を含む正極合剤層が形成されている請求項1〜5のいずれかに記載の電池。 The positive electrode has a main body portion and a current collecting tab portion that protrudes from the main body portion in a plan view and is narrower than the main body portion,
The battery according to claim 1, wherein a positive electrode mixture layer containing a positive electrode active material is formed on one side or both sides of a current collector in the main body portion of the positive electrode.
前記2枚のセパレータは、前記正極の本体部全面を覆う主体部と、前記主体部から突出し、前記正極の集電タブ部の、少なくとも本体部との境界部を含む部分を覆う張り出し部とを有しており、かつ前記2枚のセパレータは、その主体部の周縁部の少なくとも一部において、互いに溶着された接合部を有している請求項6に記載の電池。 At least a separator made of a microporous film made of a thermoplastic resin is disposed on both sides of the positive electrode facing both sides of the negative electrode,
The two separators include a main body that covers the entire surface of the main body of the positive electrode, and an overhang that protrudes from the main body and covers at least a portion of the current collecting tab of the positive electrode that includes a boundary with the main body. The battery according to claim 6, wherein the two separators have bonding portions welded to each other at least at a part of the peripheral edge of the main body.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2010204998A JP5495270B2 (en) | 2010-09-14 | 2010-09-14 | battery |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2010204998A JP5495270B2 (en) | 2010-09-14 | 2010-09-14 | battery |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2012064313A true JP2012064313A (en) | 2012-03-29 |
JP5495270B2 JP5495270B2 (en) | 2014-05-21 |
Family
ID=46059849
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2010204998A Active JP5495270B2 (en) | 2010-09-14 | 2010-09-14 | battery |
Country Status (1)
Country | Link |
---|---|
JP (1) | JP5495270B2 (en) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013004458A1 (en) | 2012-03-21 | 2013-09-26 | Hitachi Automotive Systems, Ltd. | Electric power steering device |
CN104253287A (en) * | 2013-06-26 | 2014-12-31 | 东莞市振华新能源科技有限公司 | A positioning method for a Li-ion button cell laminate |
JP2015533013A (en) * | 2012-09-11 | 2015-11-16 | ルートジェイド インコーポレイテッド | Multilayer secondary battery |
WO2018021128A1 (en) * | 2016-07-26 | 2018-02-01 | 日本電気株式会社 | Electrode assembly and manufacturing method therefor |
WO2018021129A1 (en) * | 2016-07-26 | 2018-02-01 | 日本電気株式会社 | Electrode assembly and manufacturing method therefor |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57189464A (en) * | 1981-05-15 | 1982-11-20 | Hitachi Maxell Ltd | Manufacture of organic electrolyte battery |
JPH05290891A (en) * | 1992-04-13 | 1993-11-05 | Hitachi Maxell Ltd | Coin type lithium secondary cell |
JPH11354109A (en) * | 1998-06-10 | 1999-12-24 | Toshiba Battery Co Ltd | Battery electrode blanking device |
JP2009224276A (en) * | 2008-03-18 | 2009-10-01 | Hitachi Maxell Ltd | Flat rectangular battery |
JP2009289695A (en) * | 2008-05-30 | 2009-12-10 | Hitachi Maxell Ltd | Flat battery |
JP2009289621A (en) * | 2008-05-29 | 2009-12-10 | Hitachi Maxell Ltd | Flat battery |
-
2010
- 2010-09-14 JP JP2010204998A patent/JP5495270B2/en active Active
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS57189464A (en) * | 1981-05-15 | 1982-11-20 | Hitachi Maxell Ltd | Manufacture of organic electrolyte battery |
JPH05290891A (en) * | 1992-04-13 | 1993-11-05 | Hitachi Maxell Ltd | Coin type lithium secondary cell |
JPH11354109A (en) * | 1998-06-10 | 1999-12-24 | Toshiba Battery Co Ltd | Battery electrode blanking device |
JP2009224276A (en) * | 2008-03-18 | 2009-10-01 | Hitachi Maxell Ltd | Flat rectangular battery |
JP2009289621A (en) * | 2008-05-29 | 2009-12-10 | Hitachi Maxell Ltd | Flat battery |
JP2009289695A (en) * | 2008-05-30 | 2009-12-10 | Hitachi Maxell Ltd | Flat battery |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102013004458A1 (en) | 2012-03-21 | 2013-09-26 | Hitachi Automotive Systems, Ltd. | Electric power steering device |
JP2015533013A (en) * | 2012-09-11 | 2015-11-16 | ルートジェイド インコーポレイテッド | Multilayer secondary battery |
CN104253287A (en) * | 2013-06-26 | 2014-12-31 | 东莞市振华新能源科技有限公司 | A positioning method for a Li-ion button cell laminate |
WO2018021128A1 (en) * | 2016-07-26 | 2018-02-01 | 日本電気株式会社 | Electrode assembly and manufacturing method therefor |
WO2018021129A1 (en) * | 2016-07-26 | 2018-02-01 | 日本電気株式会社 | Electrode assembly and manufacturing method therefor |
JPWO2018021128A1 (en) * | 2016-07-26 | 2019-05-09 | 日本電気株式会社 | Electrode assembly and method of manufacturing the same |
JPWO2018021129A1 (en) * | 2016-07-26 | 2019-05-09 | 日本電気株式会社 | Electrode assembly and method of manufacturing the same |
US11233296B2 (en) | 2016-07-26 | 2022-01-25 | Nec Corporation | Electrode assembly and manufacturing method therefor |
JP7014164B2 (en) | 2016-07-26 | 2022-02-15 | 日本電気株式会社 | Electrode assembly and its manufacturing method |
JP7020412B2 (en) | 2016-07-26 | 2022-02-16 | 日本電気株式会社 | Electrode assembly and its manufacturing method |
Also Published As
Publication number | Publication date |
---|---|
JP5495270B2 (en) | 2014-05-21 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5735096B2 (en) | Non-aqueous secondary battery manufacturing method and non-aqueous secondary battery manufacturing method | |
EP2495798B1 (en) | Flat nonaqueous secondary battery | |
JP5483587B2 (en) | Battery and manufacturing method thereof | |
JP2011159491A (en) | Flat nonaqueous secondary battery | |
JP6081745B2 (en) | Flat non-aqueous secondary battery | |
JP5495270B2 (en) | battery | |
JP5348720B2 (en) | Flat non-aqueous secondary battery | |
JP2014049371A (en) | Flat type nonaqueous secondary battery and manufacturing method thereof | |
JP5562655B2 (en) | Flat non-aqueous secondary battery | |
JP2012064366A (en) | Flat-shaped nonaqueous secondary battery and manufacturing method thereof | |
JP6283288B2 (en) | Flat non-aqueous secondary battery | |
JP5377249B2 (en) | Flat non-aqueous secondary battery | |
JP2011129330A (en) | Flat type nonaqueous secondary battery | |
JP5528304B2 (en) | Flat non-aqueous secondary battery | |
JP6240265B2 (en) | Method for manufacturing flat non-aqueous secondary battery | |
JP5528305B2 (en) | Flat non-aqueous secondary battery | |
JP5473063B2 (en) | Flat non-aqueous secondary battery and manufacturing method thereof | |
JP5562654B2 (en) | Flat non-aqueous secondary battery | |
JP2011154784A (en) | Flat nonaqueous secondary battery | |
JP5681358B2 (en) | Flat non-aqueous secondary battery | |
JP5566671B2 (en) | Flat non-aqueous secondary battery | |
JP2011187266A (en) | Flat nonaqueous secondary battery | |
JP5377250B2 (en) | Flat non-aqueous secondary battery | |
JP2011187392A (en) | Flat nonaqueous secondary battery | |
JP2009043424A (en) | Flat shape nonaqueous electrolytic liquid secondary battery |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A711 | Notification of change in applicant |
Free format text: JAPANESE INTERMEDIATE CODE: A712 Effective date: 20130121 |
|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20130419 |
|
A977 | Report on retrieval |
Free format text: JAPANESE INTERMEDIATE CODE: A971007 Effective date: 20140129 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20140226 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20140226 |
|
R150 | Certificate of patent or registration of utility model |
Ref document number: 5495270 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |