JP2013206724A - Nonaqueous electrolyte secondary battery - Google Patents
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- 239000011255 nonaqueous electrolyte Substances 0.000 title claims abstract description 81
- 239000002904 solvent Substances 0.000 claims abstract description 48
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- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims abstract description 30
- 150000005678 chain carbonates Chemical class 0.000 claims abstract description 29
- 239000003792 electrolyte Substances 0.000 claims abstract description 18
- 150000003839 salts Chemical class 0.000 claims abstract description 15
- FSSPGSAQUIYDCN-UHFFFAOYSA-N 1,3-Propane sultone Chemical compound O=S1(=O)CCCO1 FSSPGSAQUIYDCN-UHFFFAOYSA-N 0.000 claims abstract description 14
- 239000003125 aqueous solvent Substances 0.000 claims description 49
- QHTJSSMHBLGUHV-UHFFFAOYSA-N 2-methylbutan-2-ylbenzene Chemical compound CCC(C)(C)C1=CC=CC=C1 QHTJSSMHBLGUHV-UHFFFAOYSA-N 0.000 claims description 16
- 239000007773 negative electrode material Substances 0.000 claims description 15
- 239000007774 positive electrode material Substances 0.000 claims description 13
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- -1 lithium transition metal Chemical class 0.000 claims description 12
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- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 3
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 3
- 239000002648 laminated material Substances 0.000 claims description 2
- 238000003860 storage Methods 0.000 abstract description 35
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 description 35
- 229910001416 lithium ion Inorganic materials 0.000 description 35
- 229910013870 LiPF 6 Inorganic materials 0.000 description 18
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- 230000000052 comparative effect Effects 0.000 description 14
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- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 4
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- 238000011084 recovery Methods 0.000 description 4
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- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 description 3
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- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
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- 229920000049 Carbon (fiber) Polymers 0.000 description 2
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 2
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- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
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- 229920001778 nylon Polymers 0.000 description 2
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- ZZXUZKXVROWEIF-UHFFFAOYSA-N 1,2-butylene carbonate Chemical compound CCC1COC(=O)O1 ZZXUZKXVROWEIF-UHFFFAOYSA-N 0.000 description 1
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- 229910004089 Li1.10(Ni0.3Co0.4Mn0.3)O2 Inorganic materials 0.000 description 1
- 229910015015 LiAsF 6 Inorganic materials 0.000 description 1
- 229910013063 LiBF 4 Inorganic materials 0.000 description 1
- 229910013684 LiClO 4 Inorganic materials 0.000 description 1
- MUBZPKHOEPUJKR-UHFFFAOYSA-N Oxalic acid Chemical compound OC(=O)C(O)=O MUBZPKHOEPUJKR-UHFFFAOYSA-N 0.000 description 1
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- 150000002148 esters Chemical class 0.000 description 1
- 125000002573 ethenylidene group Chemical group [*]=C=C([H])[H] 0.000 description 1
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- 238000010030 laminating Methods 0.000 description 1
- ACFSQHQYDZIPRL-UHFFFAOYSA-N lithium;bis(1,1,2,2,2-pentafluoroethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)C(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)C(F)(F)F ACFSQHQYDZIPRL-UHFFFAOYSA-N 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
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- XOLBLPGZBRYERU-UHFFFAOYSA-N tin dioxide Chemical compound O=[Sn]=O XOLBLPGZBRYERU-UHFFFAOYSA-N 0.000 description 1
- 229910001887 tin oxide Inorganic materials 0.000 description 1
Classifications
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- 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
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- Sealing Battery Cases Or Jackets (AREA)
- Secondary Cells (AREA)
- Battery Electrode And Active Subsutance (AREA)
Abstract
Description
本発明は、積層型電極体を備えた非水電解質二次電池に関する。 The present invention relates to a nonaqueous electrolyte secondary battery including a laminated electrode body.
近年、携帯電話機、携帯型パーソナルコンピュータ、携帯型音楽プレイヤー等の携帯型電子機器の駆動電源として、リチウムイオン電池に代表される非水電解質二次電池が多く使用されている。更に、原油価格の高騰や環境保護運動の高まりを背景として、非水電解質二次電池を用いた電気自動車（ＥＶ）、ハイブリッド電気自動車（ＨＥＶ）、プラグインハイブリッド電気自動車（ＰＨＥＶ）、電動バイク等の電動車両の開発が活発に行われている。また、深夜電力や太陽光発電の電力を貯蔵することを目的とした大型蓄電システムに用いられる二次電池として中大型の非水電解質二次電池の開発が進められている。 In recent years, non-aqueous electrolyte secondary batteries represented by lithium-ion batteries have been frequently used as driving power sources for portable electronic devices such as cellular phones, portable personal computers, and portable music players. Furthermore, against the backdrop of soaring crude oil prices and increasing environmental protection movements, electric vehicles (EV), hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), electric motorcycles, etc. using non-aqueous electrolyte secondary batteries Electric vehicles are being actively developed. Further, development of medium-sized non-aqueous electrolyte secondary batteries is being promoted as a secondary battery used in a large power storage system for the purpose of storing midnight power or photovoltaic power generation.
このような電動車両や大型蓄電システム等に用いられる非水電解質二次電池については、高容量、高エネルギー密度であると共に、長期間放置しても電池特性の劣化が少ない優れた保存特性を有することが求められる。また、電動車両や大型蓄電システム等に用いられる非水電解質二次電池では、要求される電池寿命は小型携帯機器用の二次電池に比べて長く、充放電サイクルが進んでも電池特性が低下しない優れたサイクル特性が求められる。 Non-aqueous electrolyte secondary batteries used in such electric vehicles and large power storage systems have high capacity and high energy density, and excellent storage characteristics with little deterioration of battery characteristics even when left for a long period of time. Is required. In addition, non-aqueous electrolyte secondary batteries used in electric vehicles, large power storage systems, etc. require a longer battery life than secondary batteries for small portable devices, and the battery characteristics do not deteriorate even if the charge / discharge cycle progresses. Excellent cycle characteristics are required.
高容量、高エネルギー密度の非水電解質二次電池としては、大面積の正極極板及び負極極板をセパレータを介して積層した積層型電極体を備えた非水電解質二次電池が有効である。しかしながら、大面積の正極極板及び負極極板をセパレータを介して積層した積層型電極体を備えた非水電解質二次電池では、電解液の分解等により発生したガスが電極体の内部から外部に抜け難くなる。そのため、充放電反応が不均一となり、充放電サイクルに伴う電池性能の劣化が加速するという課題が生じる。 As a non-aqueous electrolyte secondary battery having a high capacity and a high energy density, a non-aqueous electrolyte secondary battery having a laminated electrode body in which a positive electrode plate and a negative electrode plate having a large area are laminated via a separator is effective. . However, in a non-aqueous electrolyte secondary battery including a laminated electrode body in which a positive electrode plate and a negative electrode plate having a large area are stacked with a separator interposed therebetween, gas generated by decomposition of the electrolytic solution or the like is generated from the inside of the electrode body to the outside. It becomes difficult to come off. As a result, the charge / discharge reaction becomes non-uniform, resulting in a problem that the deterioration of the battery performance accompanying the charge / discharge cycle is accelerated.
長尺状の正極極板及び負極極板をセパレータを介して巻回した巻回型電極体の場合は、充放電に伴う電極体の膨張・収縮により、電極体に緩みや撓みが生じ易く、電極体内部で発生したガスは電極体外部に抜け易い。これに対して、積層型電極体の場合は、各部にかかる構成圧が略均一であるため、充放電により電極体が膨張・収縮しても電極体に緩みや撓みが生じ難く、電極体内部からガスが抜け難い。したがって、大面積の極板からなる積層型電極体を用いた非水電解質二次電池は、巻回型電極体を用いた非水電解質二次電池に比べ、充放電サイクルに伴う電池性能の劣化が顕著である。 In the case of a wound electrode body in which a long positive electrode plate and a negative electrode plate are wound through a separator, the electrode body is likely to loosen or bend due to expansion / contraction of the electrode body accompanying charge / discharge, The gas generated inside the electrode body tends to escape to the outside of the electrode body. On the other hand, in the case of a laminated electrode body, the component pressure applied to each part is substantially uniform. Therefore, even if the electrode body expands or contracts due to charging / discharging, the electrode body is unlikely to loosen or bend. Gas is difficult to escape from. Therefore, the non-aqueous electrolyte secondary battery using a laminated electrode body composed of a large-area electrode plate is deteriorated in battery performance due to the charge / discharge cycle compared to the non-aqueous electrolyte secondary battery using a wound electrode body. Is remarkable.
保存特性やサイクル特性等に優れた非水電解質二次電池を提供するための技術として、下記特許文献１では、正極、負極および非水溶媒に電解質塩が溶解されている非水電解液からなるリチウム二次電池において、正極がリチウム複合酸化物を含む材料であり、負極がグラファイトを含む材料であり、該非水電解液中にシュウ酸ジアルキルを含有し、且つビニレンカーボネートおよび／または１，３−プロパンスルトンを含有することを特徴とするリチウム二次電池が提案されている。また、下記特許文献２では、非水溶媒に電解質塩が溶解されている非水電解液であって、特定のペンタフルオロフェニルオキシ化合物、そしてビニレンカーボネートおよび／または１，３− プロパンスルトンを含むことを特徴とする非水電解液が提案されている。 As a technique for providing a non-aqueous electrolyte secondary battery excellent in storage characteristics, cycle characteristics, etc., in Patent Document 1 below, it comprises a non-aqueous electrolyte solution in which an electrolyte salt is dissolved in a positive electrode, a negative electrode, and a non-aqueous solvent. In the lithium secondary battery, the positive electrode is a material containing a lithium composite oxide, the negative electrode is a material containing graphite, the non-aqueous electrolyte contains dialkyl oxalate, and vinylene carbonate and / or 1,3- A lithium secondary battery characterized by containing propane sultone has been proposed. Further, in Patent Document 2 below, a nonaqueous electrolytic solution in which an electrolyte salt is dissolved in a nonaqueous solvent, which contains a specific pentafluorophenyloxy compound and vinylene carbonate and / or 1,3-propane sultone. Non-aqueous electrolytes characterized by the above have been proposed.
上記特許文献１あるいは２で提案されている技術は、巻回型電極体を備えた非水電解質二次電池においては有効であると考えられる。しかしながら、大面積の正極極板及び負極極板からなる積層型電極体を備えた非水電解質二次電池においては、高温状態での保存中や充放電サイクル中に電極体内部で発生したガスが電極体外部に抜け難いため、上記特許文献１あるいは２で提案されている技術を用いても、高温状態で電池を保存した場合の電池容量の低下や、充放電サイクルに伴う電池容量の低下は十分に抑制できなかった。 The technique proposed in Patent Document 1 or 2 is considered to be effective in a nonaqueous electrolyte secondary battery including a wound electrode body. However, in a non-aqueous electrolyte secondary battery having a laminated electrode body composed of a positive electrode plate and a negative electrode plate having a large area, the gas generated inside the electrode body during storage at a high temperature or during a charge / discharge cycle Since it is difficult to come out of the electrode body, even if the technique proposed in Patent Document 1 or 2 is used, the battery capacity is reduced when the battery is stored in a high temperature state, or the battery capacity is reduced due to the charge / discharge cycle. It was not able to suppress enough.
本発明は上記の課題を解決するものであり、高温保存特性及びサイクル特性に優れた非水電解質二次電池を提供することを目的とする。 The present invention solves the above-described problems, and an object thereof is to provide a non-aqueous electrolyte secondary battery excellent in high-temperature storage characteristics and cycle characteristics.
本発明の非水電解質二次電池は正極芯体の表面に正極活物質層が形成された方形状の正極極板と、負極芯体の表面に負極活物質層が形成された方形状の負極極板とをセパレータを介して積層した積層型電極体を非水電解質と共に外装体に収納した非水電解質二次電池であって、前記正極極板の幅及び高さがそれぞれ１００ｍｍ以上であり、前記負極極板の幅及び高さがそれぞれ１００ｍｍ以上であり、前記積層型電極体は１０枚以上の前記正極極板と１０枚以上の前記負極極板をセパレータを介して積層したものであり、前記非水電解質は非水溶媒、電解質塩、ビニレンカーボネート、及び１，３−プロパンスルトンを含有し、前記非水溶媒中の鎖状カーボネートの割合が前記非水溶媒に対して６５体積％以上であり、前記鎖状カーボネート中のジエチルカーボネートの割合が前記鎖状カーボネートに対して７０体積％以上であり、前記ビニレンカーボネートの含有量が前記非水溶媒の総質量に対して２．０〜５．０質量％であり、前記１，３−プロパンスルトンの含有量が前記非水溶媒の総質量に対して０．１〜２．０質量％であることを特徴とする。 The nonaqueous electrolyte secondary battery of the present invention includes a square positive electrode plate having a positive electrode active material layer formed on the surface of the positive electrode core, and a square negative electrode having a negative electrode active material layer formed on the surface of the negative electrode core. A non-aqueous electrolyte secondary battery in which an electrode body and a laminated electrode body laminated via a separator are housed in an exterior body together with a non-aqueous electrolyte, each of the positive electrode plate having a width and a height of 100 mm or more, The negative electrode plate has a width and height of 100 mm or more, respectively, and the laminated electrode body is obtained by laminating 10 or more positive electrode plates and 10 or more negative electrode plates via a separator, The non-aqueous electrolyte contains a non-aqueous solvent, an electrolyte salt, vinylene carbonate, and 1,3-propane sultone, and the proportion of the chain carbonate in the non-aqueous solvent is 65% by volume or more with respect to the non-aqueous solvent. Yes, the chain carbonate The proportion of diethyl carbonate is 70% by volume or more with respect to the chain carbonate, the content of the vinylene carbonate is 2.0 to 5.0% by mass with respect to the total mass of the non-aqueous solvent, The content of 1,3-propane sultone is 0.1 to 2.0% by mass with respect to the total mass of the nonaqueous solvent.
本発明によると、幅及び高さがそれぞれ１００ｍｍ以上の方形状の正極極板と幅及び高さがそれぞれ１００ｍｍ以上の方形状の負極極板とを、セパレータを介してそれぞれ１０枚以上積層した積層型電極体を備えた、高容量の非水電解質二次電池が得られる。更に、非水電解質が鎖状カーボネートであるジエチルカーボネート、ビニレンカーボネート、及び１，３−プロパンスルトンを含有し、非水溶媒中の鎖状カーボネートの割合を非水溶媒に対して６５体積％以上、鎖状カーボネート中のジエチルカーボネートの割合を鎖状カーボネートに対して７０体積％以上とし、ビニレンカーボネートの含有量を非水溶媒の総質量に対して２．０〜５．０質量％とし、１，３−プロパンスルトンの含有量を非水溶媒の総質量に対して０．１〜２．０質量％とすることにより、大面積の正極極板及び負極極板を用いた積層型電極体を備えた非水電解質二次電池であっても、高温保存特性及びサイクル特性に優れた非水電解質二次電池が得られる。 According to the present invention, a laminate in which 10 or more square positive electrode plates each having a width and a height of 100 mm or more and a square negative electrode plate having a width and a height of 100 mm or more are laminated via a separator. A high-capacity nonaqueous electrolyte secondary battery provided with a mold electrode body is obtained. Furthermore, the nonaqueous electrolyte contains a chain carbonate such as diethyl carbonate, vinylene carbonate, and 1,3-propane sultone, and the proportion of the chain carbonate in the nonaqueous solvent is 65% by volume or more with respect to the nonaqueous solvent. The proportion of diethyl carbonate in the chain carbonate is 70% by volume or more with respect to the chain carbonate, the content of vinylene carbonate is 2.0 to 5.0% by mass with respect to the total mass of the nonaqueous solvent, By setting the content of 3-propane sultone to 0.1 to 2.0% by mass with respect to the total mass of the nonaqueous solvent, a multilayer electrode body using a large-area positive electrode plate and negative electrode plate is provided. Even if it is a nonaqueous electrolyte secondary battery, a nonaqueous electrolyte secondary battery excellent in high-temperature storage characteristics and cycle characteristics can be obtained.
なお、本発明では、各極板において集電タブが設けられた辺の長さを「幅」とし、集電タブが設けられた辺と垂直な辺の長さを「高さ」とする。また、「幅」及び「高さ」は、極板において活物質層が形成されている領域の長さとする。 In the present invention, the length of the side where the current collecting tab is provided in each electrode plate is referred to as “width”, and the length of the side perpendicular to the side where the current collecting tab is provided is referred to as “height”. The “width” and “height” are the lengths of the regions where the active material layer is formed on the electrode plate.
また、本発明では、正極極板と負極極板をそれぞれ１０枚以上積層した積層型電極体を用いることにより、耐変形強度が向上し、衝撃に対して安定な非水電解質二次電池が得られる。 In the present invention, a non-aqueous electrolyte secondary battery having improved deformation resistance and stable against impact is obtained by using a laminated electrode body in which 10 or more positive electrode plates and 10 negative electrode plates are stacked. It is done.
本発明では、鎖状カーボネートとして、ジメチルカーボネート、ジエチルカーボ
ネート、及びメチルエチルカーボネートからなる群から選ばれる少なくとも１種を用いる
ことが好ましい。
In the present invention, it is preferable to use at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate as the chain carbonate.
本発明において、前記正極活物質層は、正極活物質としてＬｉａ(ＮｉｂＣｏｃＭｎｄ）ＭｅＯ２（ここで、１．０５≦ａ≦１．２０、０．３≦ｂ≦０．６、ｂ＋ｃ＋ｄ＝１、０≦ｅ≦０．０５、Ｍ＝Ｔｉ、Ｎｂ、Ｍｏ、Ｚｎ、Ａｌ、Ｓｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｚｒ、Ｗよりなる群から選択される少なくとも１種の元素）で表されるリチウム遷移金属複合酸化物を含有することが好ましい。 In the present invention, the positive active material layer, in Li a (Ni b Co c Mn d) M e O 2 ( wherein as a positive electrode active material, 1.05 ≦ a ≦ 1.20,0.3 ≦ b ≦ 0 .6, b + c + d = 1, 0 ≦ e ≦ 0.05, M = Ti, Nb, Mo, Zn, Al, Sn, Mg, Ca, Sr, Zr, W, at least one element selected from the group It is preferable to contain the lithium transition metal complex oxide represented by this.
正極活物質であるリチウム遷移金属複合酸化物の構造内に過剰Ｌｉが存在すること
で、結晶構造が安定化し、サイクル特性に優れた非水電解質二次電池が得られる。
The presence of excess Li in the structure of the lithium transition metal composite oxide that is the positive electrode active material stabilizes the crystal structure and provides a nonaqueous electrolyte secondary battery with excellent cycle characteristics.
本発明では、正極活物質として、Ｌｉａ(ＮｉｂＣｏｃＭｎｄ）ＭｅＯ２（ここで、１．０５≦ａ≦１．２０、０．３≦ｂ≦０．６、０＜ｃ、０＜ｄ、ｂ＋ｃ＋ｄ＝１、０≦ｅ≦０．０５、Ｍ＝Ｔｉ、Ｎｂ、Ｍｏ、Ｚｎ、Ａｌ、Ｓｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｚｒ、Ｗよりなる群から選択される少なくとも１種の元素）で表されるリチウム遷移金属複合酸化物を用いることがより好ましい。 In the present invention, as the positive electrode active material, Li a (Ni b Co c Mn d) M e O 2 ( wherein, 1.05 ≦ a ≦ 1.20,0.3 ≦ b ≦ 0.6,0 <c , 0 <d, b + c + d = 1, 0 ≦ e ≦ 0.05, M = Ti, Nb, Mo, Zn, Al, Sn, Mg, Ca, Sr, Zr, W, at least one selected from the group It is more preferable to use a lithium transition metal composite oxide represented by
正極活物質であるリチウム遷移金属複合酸化物の構造内に過剰Ｌｉが存在するとともにＣｏ及びＭｎが存在するため、結晶構造が安定化し、サイクル特性がより優れた非水電解質二次電池が得られる。また、リチウム遷移金属複合酸化物の構造内にＴｉ、Ｎｂ、Ｍｏ、Ｚｎ、Ａｌ、Ｓｎ、Ｍｇ、Ｃａ、Ｓｒ、Ｚｒ、Ｗよりなる群から選択される少なくとも１種の元素が存在すると、よりサイクル特性が優れた非水電解質二次電池が得られる。 Since there is excess Li and Co and Mn in the structure of the lithium transition metal composite oxide, which is the positive electrode active material, a non-aqueous electrolyte secondary battery with more stable cycle characteristics can be obtained because the crystal structure is stabilized . Further, when at least one element selected from the group consisting of Ti, Nb, Mo, Zn, Al, Sn, Mg, Ca, Sr, Zr, and W is present in the structure of the lithium transition metal composite oxide, A non-aqueous electrolyte secondary battery having excellent cycle characteristics can be obtained.
本発明では、前記非水電解質がtert−アミルベンゼンを含有し、前記tert−アミルベンゼンの含有量が前記非水溶媒の総質量に対して０．５〜２．０質量％であることが好ましい。 In the present invention, the nonaqueous electrolyte preferably contains tert-amylbenzene, and the content of the tert-amylbenzene is preferably 0.5 to 2.0% by mass with respect to the total mass of the nonaqueous solvent. .
これにより、高温保存特性及びサイクル特性がより優れた非水電解質二次電池が得られる。 Thereby, a nonaqueous electrolyte secondary battery having better high-temperature storage characteristics and cycle characteristics can be obtained.
本発明では、前記非水電解質中における前記電解質塩の濃度が、１．２ｍｏｌ／Ｌ以上であることが好ましい。 In the present invention, the concentration of the electrolyte salt in the non-aqueous electrolyte is preferably 1.2 mol / L or more.
これにより、非水電解質のイオン導電性が向上し、充放電サイクル時の反応が均一となり、サイクル特性がより向上する。 Thereby, the ionic conductivity of the nonaqueous electrolyte is improved, the reaction during the charge / discharge cycle is uniform, and the cycle characteristics are further improved.
本発明では、前記負極活物質層が、ゴム系結着材を含有することが好ましい。 In the present invention, the negative electrode active material layer preferably contains a rubber-based binder.
負極活物質層における結着材としてポリフッ化ビニリデンを用いることも考えられる。しかし、ポリフッ化ビニリデンは、結着性及び膨潤性が低いため、負極活物質層中のポリフッ化ビニリデンの含有量を多くする必要があり、大面積の極板からなる積層型電極体を用いる非水電解質二次電池においては、充放電反応が不均一となり易く、サイクル特性が向上し難い。これに対して、ゴム系結着材は結着性及び膨潤性に優れるため、負極活物質層における結着材としてゴム系結着材を用いることによりサイクル特性に優れた非水電解質二次電池が得られる。ゴム系結着材としては、スチレンブタジエンゴム、ポリアクリレート等を用いることが好ましい。 It is also conceivable to use polyvinylidene fluoride as a binder in the negative electrode active material layer. However, since polyvinylidene fluoride has a low binding property and swelling property, it is necessary to increase the content of polyvinylidene fluoride in the negative electrode active material layer, and a non-layered electrode body composed of a large-area electrode plate is used. In a water electrolyte secondary battery, the charge / discharge reaction tends to be non-uniform, and the cycle characteristics are difficult to improve. On the other hand, since the rubber-based binder is excellent in binding property and swelling property, the non-aqueous electrolyte secondary battery having excellent cycle characteristics by using the rubber-based binder as the binder in the negative electrode active material layer Is obtained. As the rubber-based binder, styrene butadiene rubber, polyacrylate, or the like is preferably used.
本発明では、前記外装体は金属箔の両面に樹脂層が形成されたラミネート材からなり、前記外装体が減圧状態で封止されていることが好ましい。 In this invention, it is preferable that the said exterior body consists of a laminate material in which the resin layer was formed on both surfaces of metal foil, and the said exterior body is sealed by the pressure reduction state.
これにより、積層型電極体が均一に加圧されるため、充放電反応が均一に起こり易くなり、よりサイクル特性に優れた非水電解質二次電池が得られる。 Thereby, since the laminated electrode body is uniformly pressurized, the charge / discharge reaction easily occurs, and a nonaqueous electrolyte secondary battery having more excellent cycle characteristics can be obtained.
以下、本発明の最良の形態を詳細に説明するが、本発明はこの最良の形態になんら限定されるものではなく、その趣旨を変更しない範囲において適宜変更して実施することが可能である。 Hereinafter, the best mode of the present invention will be described in detail. However, the present invention is not limited to this best mode, and can be implemented with appropriate modifications without departing from the spirit of the present invention.
まず、本発明の実施例に係る非水電解質二次電池として、ラミネート外装体を備えたリチウムイオン電池２０を、図１〜図３に基づいて説明する。 First, as a nonaqueous electrolyte secondary battery according to an embodiment of the present invention, a lithium ion battery 20 including a laminate outer package will be described with reference to FIGS.
図１に示すように、リチウムイオン電池２０は、ラミネート外装体１の内部に積層型電極体１０が非水電解液とともに収容され、ラミネート外装体１の溶着封止部１’から、正極集電タブ４及び負極集電タブ５にそれぞれ接続された正極端子６及び負極端子７が突出している。ラミネート外装体１の溶着封止部１’において、正極端子６及び負極端子７とラミネート外装体１の間には、それぞれ正極タブ樹脂８、負極タブ樹脂９が配置されている。 As shown in FIG. 1, a lithium ion battery 20 includes a laminated electrode body 10 in which a laminated electrode body 10 is accommodated together with a non-aqueous electrolyte, and a positive electrode current collector from a welded and sealed portion 1 ′ of the laminate outer body 1. A positive terminal 6 and a negative terminal 7 connected to the tab 4 and the negative current collecting tab 5 respectively protrude. A positive electrode tab resin 8 and a negative electrode tab resin 9 are disposed between the positive electrode terminal 6 and the negative electrode terminal 7 and the laminate outer package 1 in the welded and sealed portion 1 ′ of the laminate outer package 1, respectively.
正極極板２は図２Ａに示すように、正極芯体の両面に正極活物質層２ａが形成されており、一方の端部からは正極活物質層２ａが形成されていない正極芯体が正極集電タブ４として突出している。負極極板３は図２Ｂに示すように、負極芯体の両面に負極活物質層３ａが形成されており、一方の端部からは負極活物質３ａが形成されていない負極芯体が負極集電タブ５として突出している。 As shown in FIG. 2A, the positive electrode plate 2 has a positive electrode active material layer 2a formed on both surfaces of the positive electrode core, and a positive electrode core without the positive electrode active material layer 2a formed from one end is a positive electrode. It protrudes as a current collecting tab 4. As shown in FIG. 2B, the negative electrode plate 3 has a negative electrode active material layer 3a formed on both sides of the negative electrode core, and a negative electrode core on which no negative electrode active material 3a is formed is formed from one end. The electric tab 5 protrudes.
積層型電極体１０は、図３に示すように、正極極板２と負極極板３とがセパレータを介して交互に積層され、最外側両面に負極極板３が配置されている。そして、その外側両面には、さらに絶縁シート１２が配置され、絶縁テープ１１により固定されている。積層型電極体１０では、正極集電タブ４及び負極集電タブ５が同じ方向に突出して、正極集電タブ４及び負極集電タブ５がそれぞれ積層される。積層された正極集電タブ４及び負極集電タブ５は、それぞれ正極端子６及び負極端子７に超音波溶接により接続される。 As shown in FIG. 3, the stacked electrode body 10 includes positive electrode plates 2 and negative electrode plates 3 that are alternately stacked via separators, and the negative electrode plates 3 are disposed on both outermost surfaces. Insulating sheets 12 are further disposed on both outer surfaces of the outer surface and fixed by insulating tape 11. In the stacked electrode body 10, the positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 protrude in the same direction, and the positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 are laminated. The stacked positive electrode current collecting tab 4 and negative electrode current collecting tab 5 are connected to the positive electrode terminal 6 and the negative electrode terminal 7 by ultrasonic welding, respectively.
この積層型電極体１０が、積層型電極体１０を収納できるようにカップ成形されたラミネートフィルムとシート状のラミネートフィルムの間に挿入される。そして、正極集電タブ４及び負極集電タブ５がラミネート外装体１の溶着封止部１’から突出するように周囲３辺が熱溶着される。その後、ラミネート外装体１における熱溶着されていない開口部から非水電解液が注液された後、ラミネート外装体１の開口部が溶着されることによりリチウムイオン電池２０が作製される。 This laminated electrode body 10 is inserted between a laminated film cup-shaped so as to accommodate the laminated electrode body 10 and a sheet-like laminated film. Then, the three surrounding sides are thermally welded so that the positive electrode current collecting tab 4 and the negative electrode current collecting tab 5 protrude from the welded sealing portion 1 ′ of the laminate outer package 1. Thereafter, a non-aqueous electrolyte is injected from an opening portion of the laminate outer package 1 that is not thermally welded, and then the opening portion of the laminate outer package 1 is welded, whereby the lithium ion battery 20 is manufactured.
次に、本発明に係るリチウムイオン電池２０の製造方法を実施例１を用いて説明する。 Next, a method for manufacturing the lithium ion battery 20 according to the present invention will be described using Example 1.
[実施例１]
〔正極極板の作製〕
正極活物質としてのＬｉ１．１０(Ｎｉ０．３Ｃｏ０．４Ｍｎ０．３）Ｏ２を９４質量％と、導電剤としてのカーボンブラックを３質量％と、結着剤としてのポリフッ化ビニリデン（ＰＶｄＦ）を３質量％と、溶剤としてのＮ−メチル−２−ピロリドン（ＮＭＰ）溶液とを混合して正極合剤スラリーを調製した。この正極合剤スラリーを、正極芯体としてのアルミニウム箔（厚み：２０μｍ）の両面にドクターブレード法により塗布した。その後、加熱することにより溶剤を除去し、ローラーで厚み０．２ｍｍにまで圧縮した後、図２Ａに示すように幅Ｌ１＝１５０ｍｍ、高さＬ２＝１５０ｍｍになるように切断して、両面に正極活物質層２ａを有する正極極板２を作製した。この際、正極極板２の端部から幅Ｌ３＝３０ｍｍ、高さＬ４＝２０ｍｍの正極活物質層２ａが形成されていない正極芯体を延出させて正極集電タブ４とした。
[Example 1]
[Preparation of positive electrode plate]
94% by mass of Li 1.10 (Ni 0.3 Co 0.4 Mn 0.3 ) O 2 as a positive electrode active material, 3% by mass of carbon black as a conductive agent, and polyfluorination as a binder A positive electrode mixture slurry was prepared by mixing 3% by mass of vinylidene (PVdF) and an N-methyl-2-pyrrolidone (NMP) solution as a solvent. This positive electrode mixture slurry was applied to both surfaces of an aluminum foil (thickness: 20 μm) as a positive electrode core by a doctor blade method. Thereafter, the solvent is removed by heating, and the roller is compressed to a thickness of 0.2 mm, and then cut to have a width L1 = 150 mm and a height L2 = 150 mm as shown in FIG. A positive electrode plate 2 having an active material layer 2a was produced. At this time, a positive electrode core tab in which the positive electrode active material layer 2 a having a width L 3 = 30 mm and a height L 4 = 20 mm was not formed from the end of the positive electrode plate 2 to form a positive electrode current collecting tab 4.
〔負極極板の作製〕
負極活物質としての黒鉛を９８質量％と、カルボキシメチルセルロース（ＣＭＣ）を１質量％と、スチレンブタジエンゴム（ＳＢＲ）を１質量％と、水とを混合することにより負極合剤スラリーを得た。その後、この負極合剤スラリーを、負極芯体としての銅箔（厚み：１０μｍ）の両面にドクターブレード方により塗布した。その後、加熱することにより水を除去し、ローラーで厚み０．２ｍｍにまで圧縮した後、図２Ｂに示すように、幅Ｌ５＝１５５ｍｍ、高さＬ６＝１５５ｍｍになるように切断して、両面に負極活物質層３ａを有する負極極板３を作製した。この際、負極極板の端部から幅Ｌ７＝３０ｍｍ、高さＬ８＝２０ｍｍの負極活物質層３ａが形成されていない負極芯体を延出させて負極集電タブ５とした。
[Production of negative electrode plate]
A negative electrode mixture slurry was obtained by mixing 98% by mass of graphite as a negative electrode active material, 1% by mass of carboxymethyl cellulose (CMC), 1% by mass of styrene butadiene rubber (SBR), and water. Thereafter, the negative electrode mixture slurry was applied to both surfaces of a copper foil (thickness: 10 μm) as a negative electrode core by a doctor blade. Then, after removing water by heating and compressing to a thickness of 0.2 mm with a roller, as shown in FIG. 2B, it is cut to have a width L5 = 155 mm and a height L6 = 155 mm. A negative electrode plate 3 having a negative electrode active material layer 3a was produced. At this time, the negative electrode current collector tab 5 was formed by extending a negative electrode core body on which the negative electrode active material layer 3a having a width L7 = 30 mm and a height L8 = 20 mm was not formed from the end of the negative electrode plate.
〔非水電解液の調製〕
エチレンカーボネート（ＥＣ）とプロピレンカーボネート（ＰＣ）とジエチルカーボネート（ＤＥＣ）を体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ビニレンカーボネート(ＶＣ)を非水溶媒の総質量に対して３．０質量％、１，３−プロパンスルトン（ＰＳ）を非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加し非水電解液を調整した。本発明における非水溶媒中の各溶媒の体積比は、２５℃、1気圧の条件下における比率である。
(Preparation of non-aqueous electrolyte)
LiPF 6 was dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which ethylene carbonate (EC), propylene carbonate (PC), and diethyl carbonate (DEC) were mixed at a volume ratio of 20: 5: 75. Vinylene carbonate (VC) is 3.0% by mass with respect to the total mass of the nonaqueous solvent, 1,3-propane sultone (PS) is 1.0% by mass with respect to the total mass of the nonaqueous solvent, and tert-amylbenzene. Was added in an amount of 1.5% by mass based on the total mass of the non-aqueous solvent to prepare a non-aqueous electrolyte. The volume ratio of each solvent in the non-aqueous solvent in the present invention is a ratio under conditions of 25 ° C. and 1 atm.
〔積層型電極体の作製〕
上記の方法で作製した正極極板２を２０枚と、上記の方法で作成した負極極板３を２１枚とを、ポリエチレン製微多孔膜セパレータ（１５５ｍｍ×１５５ｍｍ、厚さ２０μｍ）を介して交互に積層し積層型電極体１０を作製した。なお、積層型電極体１０においては、最外側両面に負極極板３を配置し、さらにその外側両面に絶縁シート１２を配置し、絶縁テープ１１により固定した。
[Production of laminated electrode body]
20 positive electrode plates 2 produced by the above method and 21 negative electrode plates 3 produced by the above method are alternately arranged via a polyethylene microporous membrane separator (155 mm × 155 mm, thickness 20 μm). To laminate electrode body 10. In the laminated electrode body 10, the negative electrode plate 3 is disposed on both outermost surfaces, and the insulating sheet 12 is disposed on both outer surfaces, and is fixed by the insulating tape 11.
〔集電端子の溶接〕
各正極極板２の正極集電タブ４を一つに束ね、幅３０ｍｍ、高さ５０ｍｍ、厚み０．４ｍｍのアルミニウム板よりなる正極端子６に超音波溶接法により接合した。また、各負極極板３の負極集電タブ５を一つに束ね、幅３０ｍｍ、長さ５０ｍｍ、厚み０．４ｍｍの銅板よりなる負極端子７に超音波溶接法により接合した。ここで、正極端子６及び負極端子７にはそれぞれ正極タブ樹脂８及び負極タブ樹脂９が接着されている。正極タブ樹脂８及び負極タブ樹脂９は後述するように正極端子６及び負極端子７とラミネート外装体１の間にそれぞれ介在し、正極端子６及び負極端子７とラミネート外装体１の接着性を向上させることにより、ラミネート外装体１の封止性を向上させる。
[Welding of current collector terminal]
The positive electrode current collecting tabs 4 of the respective positive electrode plates 2 were bundled together and joined to the positive electrode terminal 6 made of an aluminum plate having a width of 30 mm, a height of 50 mm, and a thickness of 0.4 mm by an ultrasonic welding method. Moreover, the negative electrode current collection tab 5 of each negative electrode plate 3 was bundled together, and it joined to the negative electrode terminal 7 which consists of a copper plate of width 30mm, length 50mm, and thickness 0.4mm by the ultrasonic welding method. Here, the positive electrode tab resin 8 and the negative electrode tab resin 9 are bonded to the positive electrode terminal 6 and the negative electrode terminal 7, respectively. As will be described later, the positive electrode tab resin 8 and the negative electrode tab resin 9 are interposed between the positive electrode terminal 6 and the negative electrode terminal 7 and the laminate outer package 1, respectively, thereby improving the adhesion between the positive electrode terminal 6 and the negative electrode terminal 7 and the laminate outer package 1. By doing so, the sealing performance of the laminate outer package 1 is improved.
〔外装体への封入〕
あらかじめ電極体が設置できるようにカップ状に成形したラミネート外装体１に、上記
の方法で作製した積層型電極体１０を挿入し、正極端子６及び負極端子７のみがラミネート外装体１より外部に突出するようにして、正極端子６及び負極端子７がある辺を除く３辺のうち１辺を残し、３辺を熱融着した。ここで、正極タブ樹脂８及び負極タブ樹脂９は、正極端子６及び負極端子７とラミネート外装体の間にそれぞれ介在する状態となる。
[Encapsulation in exterior body]
The laminated electrode body 10 produced by the above-described method is inserted into the laminated exterior body 1 formed in a cup shape so that the electrode body can be installed in advance, and only the positive electrode terminal 6 and the negative electrode terminal 7 are outside the laminate exterior body 1. The three sides were heat-sealed, leaving one side out of the three sides excluding the side with the positive electrode terminal 6 and the negative electrode terminal 7 so as to protrude. Here, the positive electrode tab resin 8 and the negative electrode tab resin 9 are respectively interposed between the positive electrode terminal 6 and the negative electrode terminal 7 and the laminate outer package.
〔電解液の封入、密封化〕
上記ラミネート外装体１の熱溶着していない１辺から、上記の方法で調製した非水電解液を注入した。その後、ラミネート外装体１の内部が減圧状態（９０ｋＰａ）になるようにして、ラミネート外装体１における熱溶着していない１辺を熱溶着して、実施例１のリチウムイオン電池とした。
[Encapsulation and sealing of electrolyte]
The non-aqueous electrolyte prepared by the above method was injected from one side of the laminate outer package 1 that was not thermally welded. Then, the inside of the laminate outer package 1 was in a reduced pressure state (90 kPa), and one side of the laminate outer package 1 that was not thermally welded was thermally welded to obtain a lithium ion battery of Example 1.
[実施例２]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．２ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例２のリチウムイオン電池とした。
[Example 2]
LiPF 6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 1.0% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 2 was obtained.
[実施例３]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．０ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例３のリチウムイオン電池とした。
[Example 3]
LiPF 6 is dissolved at a concentration of 1.0 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 1.0% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 3 was obtained.
[実施例４]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．２ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して２．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例４のリチウムイオン電池とした。
[Example 4]
LiPF 6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 2 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 1.0% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 4 was obtained.
[実施例５]
ＥＣとＰＣとＤＥＣを体積比で２０：１５：６５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例５のリチウムイオン電池とした。
[Example 5]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20:15:65, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 1.0% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 5 was obtained.
[実施例６]
ＥＣとＰＣとＤＥＣとＭＥＣを体積比で２０：５：５２．５：２２．５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例６のリチウムイオン電池とした。
[Example 6]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, DEC, and MEC are mixed at a volume ratio of 20: 5: 52.5: 22.5, and VC is non-aqueous. 3.0% by mass with respect to the total mass of the solvent, 1.0% by mass with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent A lithium ion battery was produced in the same manner as in Example 1 except that the non-aqueous electrolyte was used, and a lithium ion battery of Example 6 was obtained.
[実施例７]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、
ＰＳを非水溶媒の総質量に対して０．５質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例７のリチウムイオン電池とした。
[Example 7]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0 mass%,
Except for using nonaqueous electrolytic solution in which PS was added at 0.5% by mass with respect to the total mass of the nonaqueous solvent and tert-amylbenzene was added at 1.5% by mass with respect to the total mass of the nonaqueous solvent. A lithium ion battery was produced in the same manner as in Example 1 to obtain a lithium ion battery of Example 7.
[実施例８]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．５質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例８のリチウムイオン電池とした。
[Example 8]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 1.5% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 8 was obtained.
[実施例９]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して２．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、実施例９のリチウムイオン電池とした。
[Example 9]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. 0.0% by mass, 2.0% by mass of PS with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent were used. Except for this, a lithium ion battery was produced in the same manner as in Example 1, and a lithium ion battery of Example 9 was obtained.
[比較例１]
ＥＣとＰＣとＤＥＣとＭＥＣを体積比で２０：５：２２．５：５２．５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．４ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ＰＳを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、比較例１のリチウムイオン電池とした。
[Comparative Example 1]
LiPF 6 is dissolved at a concentration of 1.4 mol / L in a non-aqueous solvent in which EC, PC, DEC, and MEC are mixed at a volume ratio of 20: 5: 22.5: 52.5, and VC is non-aqueous. 3.0% by mass with respect to the total mass of the solvent, 1.0% by mass with respect to the total mass of the nonaqueous solvent, and 1.5% by mass of tert-amylbenzene with respect to the total mass of the nonaqueous solvent A lithium ion battery was produced in the same manner as in Example 1 except that the nonaqueous electrolyte solution was used, and a lithium ion battery of Comparative Example 1 was obtained.
[比較例２]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．２ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して３．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、比較例２のリチウムイオン電池とした。
[Comparative Example 2]
LiPF 6 is dissolved at a concentration of 1.2 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 3 with respect to the total mass of the non-aqueous solvent. A lithium ion battery was prepared in the same manner as in Example 1 except that a nonaqueous electrolytic solution in which 1.5 mass% of tert-amylbenzene was added by 1.5 mass% with respect to the total mass of the nonaqueous solvent was used. The lithium ion battery of Comparative Example 2 was obtained.
[比較例３]
ＥＣとＰＣとＤＥＣを体積比で２０：５：７５の割合で混合した非水溶媒に、ＬｉＰＦ６を１．０ｍｏｌ／Ｌの濃度で溶解し、ＶＣを非水溶媒の総質量に対して１．０質量％、ｔｅｒｔ−アミルベンゼンを非水溶媒の総質量に対して１．５質量％添加した非水電解液を用いたこと以外は実施例１と同様の方法でリチウムイオン電池を作製し、比較例３のリチウムイオン電池とした。
[Comparative Example 3]
LiPF 6 is dissolved at a concentration of 1.0 mol / L in a non-aqueous solvent in which EC, PC, and DEC are mixed at a volume ratio of 20: 5: 75, and VC is 1 with respect to the total mass of the non-aqueous solvent. A lithium ion battery was prepared in the same manner as in Example 1 except that a nonaqueous electrolytic solution in which 1.5 mass% of tert-amylbenzene was added by 1.5 mass% with respect to the total mass of the nonaqueous solvent was used. The lithium ion battery of Comparative Example 3 was obtained.
[高温保存試験]
実施例１〜９、及び比較例１〜３のリチウムイオン電池について、高温保存試験を行った。高温保存試験の方法は次の通りである。各電池を２５℃の温度条件下で定電流充電(１Ｉｔ、終止電圧４．２Ｖ)‐定電圧充電(電圧４．２Ｖ、終止電流１／５０Ｉｔ)後、電流値１Ｉｔレートで２．７５Ｖまで放電し、この放電容量を保存前容量とした。次に、各電池を定電流充電(１Ｉｔ、終止電圧４．２Ｖ)‐定電圧充電(電圧４．２Ｖ、終止電流１／５０Ｉｔ)で充電した後、各電池を６０℃の温度条件下で２０日間保存した。２０日間保存した各電池を２５℃まで放冷した後、電流値１Ｉｔレートで２．７５Ｖまで放電した。その後、各電池を定電流充電(１Ｉｔ、終止電圧４．２Ｖ)‐定電圧充電(電圧４．２Ｖ、終止電流１／５０Ｉｔ)後、電流値１Ｉｔレートで２．７５Ｖまで放電し、この放電容
量を保存後復帰容量とし、以下の計算式で保存後復帰率を計算した。
保存後復帰率（％）＝（保存後復帰容量／保存前容量）×１００
[High temperature storage test]
About the lithium ion battery of Examples 1-9 and Comparative Examples 1-3, the high temperature storage test was done. The method of the high temperature storage test is as follows. Each battery is charged at constant current (1 It, end voltage 4.2 V)-constant voltage charge (voltage 4.2 V, end current 1/50 It) under a temperature condition of 25 ° C., and then discharged to 2.75 V at a current value 1 It rate. This discharge capacity was defined as the capacity before storage. Next, after charging each battery with constant current charging (1 It, end voltage 4.2 V) -constant voltage charging (voltage 4.2 V, end current 1/50 It), each battery was subjected to 20 ° C. under a temperature condition of 60 ° C. Stored for days. Each battery stored for 20 days was allowed to cool to 25 ° C. and then discharged to 2.75 V at a current value of 1 It rate. Thereafter, each battery is discharged at a constant current charge (1 It, end voltage 4.2 V) -constant voltage charge (voltage 4.2 V, end current 1/50 It) and then discharged to 2.75 V at a current value 1 It rate. Was the return capacity after storage, and the return rate after storage was calculated using the following formula.
Recovery rate after storage (%) = (Restore capacity after storage / capacity before storage) × 100
[サイクル試験]
実施例１〜４、及び比較例２、３のリチウムイオン電池について、サイクル試験を行った。サイクル試験の方法は次の通りである。各電池を２５℃の温度条件下で定電流充電(１Ｉｔ、終止電圧４．２Ｖ)‐定電圧充電(電圧４．２Ｖ、終止電流１／５０Ｉｔ)後、電流値１Ｉｔレートで２．７５Ｖまで放電した。これを１サイクル目の充放電とした。そして、１サイクル目の放電時の放電容量に対して放電容量が８０％となるまで、上記の充放電サイクルを繰り返し、１サイクル目の放電時の放電容量に対して放電容量が８０％となったサイクル数を、維持率８０％到達サイクル数とした。
[Cycle test]
A cycle test was performed on the lithium ion batteries of Examples 1 to 4 and Comparative Examples 2 and 3. The cycle test method is as follows. Each battery is charged at constant current (1 It, end voltage 4.2 V)-constant voltage charge (voltage 4.2 V, end current 1/50 It) under a temperature condition of 25 ° C., and then discharged to 2.75 V at a current value 1 It rate. did. This was defined as charge / discharge of the first cycle. The above charge / discharge cycle is repeated until the discharge capacity reaches 80% of the discharge capacity at the first cycle discharge, and the discharge capacity becomes 80% with respect to the discharge capacity at the first cycle discharge. The number of cycles obtained was defined as the number of cycles that reached a maintenance rate of 80%.
高温保存試験及びサイクル試験の結果を表１に示す。 Table 1 shows the results of the high temperature storage test and the cycle test.
非水溶媒の組成のみ異なる実施例１、実施例６、及び比較例１を比較する。非水溶媒中の鎖状カーボネートに対するＤＥＣの割合が３０体積％である比較例１では、保存後復帰率が８５．１％と低い値となった。これに対し、非水溶媒中の鎖状カーボネートに対するＤＥＣの割合が１００体積％である実施例１、非水溶媒中の鎖状カーボネートに対するＤＥＣの割合が７０体積％である実施例６では、保存後復帰率はそれぞれ９５．０％、９０．８％と高い値となった。これらのことから、非水溶媒中の鎖状カーボネートに対するＤＥＣの割合を７０体積％以上とすることで、高温保存による電池特性の劣化の少ない高温保存特性に優れた非水電解質二次電池となることが分かる。これは、非水溶媒中の鎖状カーボネートに対するＤＥＣの割合を７０体積％以上とすることで、高温保存による電解液の分解が生じ難く、ガス発生を抑制できるためと考えられる。 Example 1, Example 6, and Comparative Example 1 that differ only in the composition of the non-aqueous solvent are compared. In Comparative Example 1 in which the ratio of DEC to the chain carbonate in the non-aqueous solvent was 30% by volume, the recovery rate after storage was a low value of 85.1%. On the other hand, in Example 1 in which the ratio of DEC to the linear carbonate in the non-aqueous solvent is 100% by volume, and in Example 6 in which the ratio of DEC to the linear carbonate in the non-aqueous solvent is 70% by volume, storage is performed. The post-return rates were as high as 95.0% and 90.8%, respectively. From these things, it becomes the nonaqueous electrolyte secondary battery excellent in the high temperature storage characteristic with little deterioration of the battery characteristic by high temperature storage by making the ratio of DEC with respect to the chain carbonate in a nonaqueous solvent 70 volume% or more. I understand that. This is presumably because, when the ratio of DEC to the chain carbonate in the non-aqueous solvent is 70% by volume or more, decomposition of the electrolyte solution due to high-temperature storage hardly occurs and gas generation can be suppressed.
非水溶媒中の鎖状カーボネートの割合は、６５体積％以上とすることが好ましい。非水溶媒中の鎖状カーボネートの割合を６５％体積以上とし、鎖状カーボネート中のジエチルカーボネートを７０体積％以上とすることにより、大面積の正極極板及び負極極板からなる積層型電極体を備えた非水電解質二次電池に最適な粘度を有する非水電解質となる。したがって、非水電解質が電極体に染み込み易く、充放電反応が均一に生じ、サイクル特性に優れた非水電解質二次電池が得られる。また、このような組成の非水溶媒は、電池が高温状態となった場合でも、ガスが発生し難く、高温保存特性に優れた非水電解質二次電池が得られる。なお、非水溶媒中の鎖状カーボネートの割合は、８５体積％以下とすることが好ましい。また、非水溶媒中の鎖状カーボネートをジエチルカーボネートのみとすることもできる。非水溶媒中の鎖状カーボネートの割合が８５体積％より大きくなると、電解質塩が溶解し難くなり、また電解質塩が解離し難くなることで、非水電解質のイオン導電
性が低下するおそれがあり好ましくない。
The proportion of the chain carbonate in the non-aqueous solvent is preferably 65% by volume or more. A laminated electrode body comprising a positive electrode plate and a negative electrode plate having a large area by setting the proportion of the chain carbonate in the non-aqueous solvent to 65% by volume or more and the diethyl carbonate in the chain carbonate to 70% by volume or more. It becomes a nonaqueous electrolyte which has the optimal viscosity for a nonaqueous electrolyte secondary battery provided with. Therefore, the nonaqueous electrolyte can easily penetrate into the electrode body, the charge / discharge reaction occurs uniformly, and a nonaqueous electrolyte secondary battery excellent in cycle characteristics can be obtained. In addition, the nonaqueous solvent having such a composition is unlikely to generate gas even when the battery is in a high temperature state, and a nonaqueous electrolyte secondary battery excellent in high temperature storage characteristics can be obtained. In addition, it is preferable that the ratio of the chain carbonate in a nonaqueous solvent shall be 85 volume% or less. Further, the chain carbonate in the non-aqueous solvent can be only diethyl carbonate. When the proportion of the chain carbonate in the non-aqueous solvent is larger than 85% by volume, the electrolyte salt becomes difficult to dissolve, and the electrolyte salt becomes difficult to dissociate, which may reduce the ionic conductivity of the non-aqueous electrolyte. It is not preferable.
非水電解質中のＶＣの含有量及びＰＳの含有量のみが異なる実施例２、実施例４、及び比較例２を比較する。非水電解質中にＶＣを含有し、ＰＳを含有しない比較例２では、維持率８０％到達サイクル数が多く優れたサイクル特性を有するものの、保存後復帰率は８４．６％と低い値となった。これは、非水電解質中にＰＳが含有されていないため、高温保存時の電解液の分解によるガス発生が抑制できないためと考えられる。これに対して、非水電解質中にＶＣ及びＰＳを含有する実施例２及び実施例４では、維持率８０％到達サイクル数が多く、高い保存後復帰率を示した。このことから、大面積の正極極板及び負極極板からなる積層型電極体を備えた非水電解質二次電池において、優れた高温保存特性及びサイクル特性を得るためには、非水電解質中にＶＣ及びＰＳを含有する必要があることが分かる。なお、ＶＣの含有量は、非水溶媒に対して２．０〜５．０質量％とする必要がある。ＶＣの含有量が非水溶媒に対して２．０質量％未満となると、サイクル特性の改善効果が十分に得られない。また、ＶＣの含有量が非水溶媒に対して５．０質量％よりも多くなると、サイクル特性は改善するものの、高温保存中にガスが発生し易くなり、高温保存特性が低下するという問題が発生する。ＰＳの含有量は、非水溶媒に対して０．１〜２．０質量％とする必要がある。ＰＳの含有量が非水溶媒に対して０．１質量％未満となると、高温保存特性及びサイクル特性の改善効果が十分に得られない。また、ＰＳの含有量が非水溶媒に対して２．０質量％よりも多くなると、負極活物質層上にできる被膜が厚くなりすぎることで、電気抵抗が増大し、サイクル特性が低下するという問題が発生する。 Example 2, Example 4, and Comparative Example 2 that differ only in the content of VC and the content of PS in the nonaqueous electrolyte will be compared. In Comparative Example 2 containing VC and non-PS in the nonaqueous electrolyte, the retention rate was 80% and the number of cycles reached was excellent, but the return rate after storage was as low as 84.6%. It was. This is probably because PS is not contained in the non-aqueous electrolyte, so that gas generation due to decomposition of the electrolyte during high temperature storage cannot be suppressed. On the other hand, in Example 2 and Example 4 containing VC and PS in the nonaqueous electrolyte, the number of cycles reaching the maintenance rate of 80% was large, and a high recovery rate after storage was shown. From this, in order to obtain excellent high-temperature storage characteristics and cycle characteristics in a non-aqueous electrolyte secondary battery having a laminated electrode body composed of a positive electrode plate and a negative electrode plate having a large area, It can be seen that it needs to contain VC and PS. In addition, content of VC needs to be 2.0-5.0 mass% with respect to a non-aqueous solvent. When the content of VC is less than 2.0% by mass with respect to the nonaqueous solvent, the effect of improving the cycle characteristics cannot be sufficiently obtained. Further, when the content of VC is more than 5.0% by mass with respect to the non-aqueous solvent, although the cycle characteristics are improved, there is a problem that gas is easily generated during high-temperature storage and the high-temperature storage characteristics are deteriorated. Occur. The PS content needs to be 0.1 to 2.0 mass% with respect to the non-aqueous solvent. When the PS content is less than 0.1% by mass with respect to the non-aqueous solvent, the effect of improving the high-temperature storage characteristics and the cycle characteristics cannot be sufficiently obtained. Further, when the PS content is more than 2.0% by mass with respect to the non-aqueous solvent, the coating film formed on the negative electrode active material layer becomes too thick, which increases electrical resistance and decreases cycle characteristics. A problem occurs.
非水電解質中のＶＣの含有量及びＰＳの含有量のみが異なる実施例３、及び比較例３を比較する。ＶＣの含有量が１．０質量％であり、ＰＳを含有しない比較例３では、保存後復帰率は９５．９％と高い値であるが、維持率８０％到達サイクル数は低い値となった。これは、ＶＣの含有量が少なく、負極活物質層表面に被膜が十分に形成されず、充放電サイクルに伴うガス発生を抑制できないため、サイクル特性が低下したものと考えられる。このことからも、ＶＣの含有量は、２．０質量％以上とする必要があることが分かる。 Example 3 and Comparative Example 3 in which only the content of VC and the content of PS in the nonaqueous electrolyte are different will be compared. In Comparative Example 3 in which the VC content is 1.0 mass% and PS is not contained, the recovery rate after storage is a high value of 95.9%, but the retention rate of 80% is a low value. It was. This is presumably because the cycle characteristics deteriorated because the content of VC is small, the coating film is not sufficiently formed on the surface of the negative electrode active material layer, and gas generation associated with the charge / discharge cycle cannot be suppressed. This also shows that the content of VC needs to be 2.0% by mass or more.
電解質塩であるＬｉＰＦ６の濃度のみが異なる実施例１〜３より、電解質塩であるＬｉＰＦ６の濃度が高いほど、維持率８０％到達サイクル数が多くサイクル特性に優れることが分かる。これは、電解質塩であるＬｉＰＦ６の濃度が高くなるほど、非水電解質のイオン導電性が向上するためと考えられる。なお、電解質塩であるＬｉＰＦ６の濃度は１．２ｍｏｌ／Ｌ以上とすることが好ましく、２．０ｍｏｌ／Ｌ以下とすることが好ましい。 From Examples 1 to 3 in which only the concentration of LiPF 6 that is an electrolyte salt is different, it can be seen that the higher the concentration of LiPF 6 that is an electrolyte salt, the greater the number of cycles to reach a retention rate of 80% and the better the cycle characteristics. This is considered to be because the ionic conductivity of the non-aqueous electrolyte improves as the concentration of LiPF 6 that is an electrolyte salt increases. The concentration of LiPF 6 that is an electrolyte salt is preferably 1.2 mol / L or more, and more preferably 2.0 mol / L or less.
以上の結果より、非水電解質が鎖状カーボネートであるジエチルカーボネート、ビニレンカーボネート、及び１，３−プロパンスルトンを含有し、非水溶媒中の鎖状カーボネートの割合を非水溶媒に対して６５体積％以上、鎖状カーボネート中のジエチルカーボネートの割合を鎖状カーボネートに対して７０体積％以上とし、ビニレンカーボネートの含有量を非水溶媒の総質量に対して２．０〜５．０質量％とし、１，３−プロパンスルトンの含有量を非水溶媒の総質量に対して０．１〜２．０質量％とすることにより、大面積の正極極板及び負極極板を用いた積層型電極体を備えた非水電解質二次電池であっても、高温保存特性及びサイクル特性に優れた非水電解質二次電池となることが分かる。 From the above results, the non-aqueous electrolyte contains diethyl carbonate, vinylene carbonate, and 1,3-propane sultone, which are chain carbonates, and the proportion of the chain carbonate in the non-aqueous solvent is 65 volumes with respect to the non-aqueous solvent. %, The proportion of diethyl carbonate in the chain carbonate is 70% by volume or more with respect to the chain carbonate, and the content of vinylene carbonate is 2.0 to 5.0% by mass with respect to the total mass of the nonaqueous solvent. The laminated electrode using a large-area positive electrode plate and negative electrode plate by adjusting the content of 1,3-propane sultone to 0.1 to 2.0% by mass relative to the total mass of the nonaqueous solvent Even if it is a nonaqueous electrolyte secondary battery provided with a body, it turns out that it becomes a nonaqueous electrolyte secondary battery excellent in the high temperature storage characteristic and cycling characteristics.
本発明において、負極活物質としては、黒鉛、黒鉛化されたピッチ系炭素繊維、難黒鉛化性炭素、易黒鉛化性炭素、熱分解炭素、ガラス状炭素、有機高分子化合物焼成体、炭素繊維、活性炭、コークス、酸化スズ、珪素、酸化珪素、及びそれらの混合物等、を使用することができる。 In the present invention, as the negative electrode active material, graphite, graphitized pitch-based carbon fiber, non-graphitizable carbon, graphitizable carbon, pyrolytic carbon, glassy carbon, organic polymer compound fired body, carbon fiber , Activated carbon, coke, tin oxide, silicon, silicon oxide, and mixtures thereof can be used.
本発明において、非水電解質の非水溶媒としては、従来から非水電解質二次電池において一般的に使用されているカーボネート類、ラクトン類、エーテル類、ケトン類、エステ
ル類等を使用することができ、これらの非水溶媒の２種類以上を混合して用いることができる。特に、エチレンカーボネート、プロピレンカーボネート、ブチレンカーボネート等の環状カーボネートと、ジメチルカーボネート、エチルメチルカーボネート、ジエチルカーボネート等の鎖状カーボネートを混合して用いることが好ましい。
In the present invention, as the non-aqueous solvent of the non-aqueous electrolyte, carbonates, lactones, ethers, ketones, esters, etc. that have been generally used in non-aqueous electrolyte secondary batteries can be used. It is possible to use a mixture of two or more of these nonaqueous solvents. In particular, it is preferable to use a mixture of a cyclic carbonate such as ethylene carbonate, propylene carbonate, or butylene carbonate and a chain carbonate such as dimethyl carbonate, ethyl methyl carbonate, or diethyl carbonate.
本発明において、非水電解質の電解質塩としては、従来のリチウムイオン電池において電解質塩として一般に使用されているものを用いることができる。例えば、ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＣＦ３ＳＯ２）２、ＬｉＮ（Ｃ２Ｆ５ＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）（Ｃ４Ｆ９ＳＯ２）、ＬｉＣ（ＣＦ３ＳＯ２）３、ＬｉＣ（Ｃ２Ｆ５ＳＯ２）３、ＬｉＡｓＦ６、ＬｉＣｌＯ４、Ｌｉ２Ｂ１０Ｃｌ１０、Ｌｉ２Ｂ１２Ｃｌ１２、ＬｉＢ（Ｃ２Ｏ４）２、ＬｉＢ（Ｃ２Ｏ４）Ｆ２、ＬｉＰ（Ｃ２Ｏ４）３、ＬｉＰ（Ｃ２Ｏ４）２Ｆ２，ＬｉＰ（Ｃ２Ｏ４）Ｆ４等及びそれらの混合物が用いられる。これらの中でも、ＬｉＰＦ６が特に好ましい。 In the present invention, as the electrolyte salt of the nonaqueous electrolyte, those generally used as the electrolyte salt in the conventional lithium ion battery can be used. For example, LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (CF 3 SO 2 ) 2 , LiN (C 2 F 5 SO 2 ) 2 , LiN (CF 3 SO 2 ) (C 4 F 9 SO 2 ), LiC (CF 3 SO 2 ) 3 , LiC (C 2 F 5 SO 2 ) 3 , LiAsF 6 , LiClO 4 , Li 2 B 10 Cl 10 , Li 2 B 12 Cl 12 , LiB (C 2 O 4 ) 2 , LiB ( C 2 O 4 ) F 2 , LiP (C 2 O 4 ) 3 , LiP (C 2 O 4 ) 2 F 2 , LiP (C 2 O 4 ) F 4 and the like and mixtures thereof are used. Among these, LiPF 6 is particularly preferable.
本発明において、外装体としてラミネート外装体以外にも金属製の外装缶を用いることもできる。ラミネート外装体としては、金属シートの表面に樹脂層が形成されたものを使用することができる。例えば、金属シートとしてアルミニウム、アルミニウム合金、ステンレス等を、内層（電池内側）としてポリエチレン、ポリプロピレン等を、外層（電池外側）としてナイロン、ポリエチレンテレフタレート（ＰＥＴ）、ＰＥＴ／ナイロンの積層膜等を、それぞれ用いて構成されるものが挙げられる。 In the present invention, a metal exterior can can be used as the exterior body in addition to the laminate exterior body. As the laminate outer package, a metal sheet having a resin layer formed on the surface thereof can be used. For example, aluminum, aluminum alloy, stainless steel, etc. as the metal sheet, polyethylene, polypropylene, etc. as the inner layer (battery inside), nylon, polyethylene terephthalate (PET), PET / nylon laminated film, etc. as the outer layer (battery outside), respectively What is comprised using is mentioned.
１・・・ラミネート外装体、１’・・・溶着封止部、２・・・正極極板、３・・・負極極板、４・・・正極集電タブ、５・・・負極集電タブ、６・・・正極端子、７・・・負極端子、８・・・正極タブ樹脂、９・・・負極タブ樹脂、１０・・・積層型電極体、１１・・・絶縁テープ、１２・・・絶縁シート
DESCRIPTION OF SYMBOLS 1 ... Laminate exterior body, 1 '... welding sealing part, 2 ... positive electrode plate, 3 ... negative electrode plate, 4 ... positive electrode current collection tab, 5 ... negative electrode current collection Tab, 6 ... Positive electrode terminal, 7 ... Negative electrode terminal, 8 ... Positive electrode tab resin, 9 ... Negative electrode tab resin, 10 ... Multilayer electrode body, 11 ... Insulating tape, 12. ··Insulating sheet
Claims (7)
前記正極極板の幅及び高さがそれぞれ１００ｍｍ以上であり、前記負極極板の幅及び高さがそれぞれ１００ｍｍ以上であり、前記積層型電極体は１０枚以上の前記正極極板と１０枚以上の前記負極極板をセパレータを介して積層したものであり、
前記非水電解質は非水溶媒、電解質塩、ビニレンカーボネート、及び１，３−プロパンスルトンを含有し、前記非水溶媒中の鎖状カーボネートの割合が前記非水溶媒に対して６５体積％以上であり、前記鎖状カーボネート中のジエチルカーボネートの割合が前記鎖状カーボネートに対して７０体積％以上であり、前記ビニレンカーボネートの含有量が前記非水溶媒の総質量に対して２．０〜５．０質量％であり、前記１，３−プロパンスルトンの含有量が前記非水溶媒の総質量に対して０．１〜２．０質量％であることを特徴とする非水電解質二次電池。 A rectangular positive electrode plate having a positive electrode active material layer formed on the surface of the positive electrode core and a square negative electrode plate having a negative electrode active material layer formed on the surface of the negative electrode core were laminated via a separator. A non-aqueous electrolyte secondary battery in which a laminated electrode body is housed in a package together with a non-aqueous electrolyte,
The positive electrode plate has a width and a height of 100 mm or more, the negative electrode plate has a width and a height of 100 mm or more, and the laminated electrode body has 10 or more positive electrode plates and 10 or more. The negative electrode plate is laminated via a separator,
The non-aqueous electrolyte contains a non-aqueous solvent, an electrolyte salt, vinylene carbonate, and 1,3-propane sultone, and the proportion of the chain carbonate in the non-aqueous solvent is 65% by volume or more with respect to the non-aqueous solvent. The ratio of diethyl carbonate in the chain carbonate is 70% by volume or more with respect to the chain carbonate, and the content of the vinylene carbonate is 2.0 to 5.5 with respect to the total mass of the non-aqueous solvent. A nonaqueous electrolyte secondary battery, wherein the content of the 1,3-propane sultone is 0% by mass and the content of the 1,3-propane sultone is 0.1 to 2.0% by mass with respect to the total mass of the nonaqueous solvent.
チルエチルカーボネートからなる群から選ばれる少なくとも１種である請求項１に記載の非水電解質二次電池。 The non-aqueous electrolyte secondary battery according to claim 1, wherein the chain carbonate is at least one selected from the group consisting of dimethyl carbonate, diethyl carbonate, and methyl ethyl carbonate.
The nonaqueous electrolyte secondary battery according to any one of claims 1 to 6, wherein the exterior body is made of a laminate material in which resin layers are formed on both surfaces of a metal sheet, and the exterior body is sealed in a reduced pressure state.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170127002A (en) | 2015-03-25 | 2017-11-20 | 가부시끼가이샤 구레하 | A separator / intermediate layer laminate, a structure for a nonaqueous electrolyte secondary battery, and an aqueous latex |
| WO2018173373A1 (en) | 2017-03-21 | 2018-09-27 | 株式会社クレハ | Resin composition, separator of secondary battery, and secondary battery |
| JP2019164999A (en) * | 2018-03-16 | 2019-09-26 | 三菱ケミカル株式会社 | Nonaqueous electrolyte and energy device using the same |
| US11542382B2 (en) | 2017-03-21 | 2023-01-03 | Kureha Corporation | Gel-like electrolyte having vinylidene fluoride copolymer |
-
2012
- 2012-03-28 JP JP2012074580A patent/JP2013206724A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20170127002A (en) | 2015-03-25 | 2017-11-20 | 가부시끼가이샤 구레하 | A separator / intermediate layer laminate, a structure for a nonaqueous electrolyte secondary battery, and an aqueous latex |
| WO2018173373A1 (en) | 2017-03-21 | 2018-09-27 | 株式会社クレハ | Resin composition, separator of secondary battery, and secondary battery |
| KR20190112095A (en) | 2017-03-21 | 2019-10-02 | 가부시끼가이샤 구레하 | Resin composition, separator of secondary battery, and secondary battery |
| US11542382B2 (en) | 2017-03-21 | 2023-01-03 | Kureha Corporation | Gel-like electrolyte having vinylidene fluoride copolymer |
| JP2019164999A (en) * | 2018-03-16 | 2019-09-26 | 三菱ケミカル株式会社 | Nonaqueous electrolyte and energy device using the same |
| JP7301557B2 (en) | 2018-03-16 | 2023-07-03 | 三菱ケミカル株式会社 | NON-AQUEOUS ELECTROLYTE AND ENERGY DEVICE USING THE SAME |
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