JP5252535B2 - Non-aqueous electrolyte secondary battery - Google Patents

Non-aqueous electrolyte secondary battery Download PDF

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JP5252535B2
JP5252535B2 JP2007227721A JP2007227721A JP5252535B2 JP 5252535 B2 JP5252535 B2 JP 5252535B2 JP 2007227721 A JP2007227721 A JP 2007227721A JP 2007227721 A JP2007227721 A JP 2007227721A JP 5252535 B2 JP5252535 B2 JP 5252535B2
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woven fabric
fibers
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electrolyte secondary
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JP2009059654A (en
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昌明 木部
勝哉 三谷
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Envision AESC Energy Devices Ltd
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    • 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
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Description

本発明は、非水電解液二次電池に関し、特に炭素を負極活物質として用いる非水電解液二次電池に関するものである。   The present invention relates to a non-aqueous electrolyte secondary battery, and more particularly to a non-aqueous electrolyte secondary battery using carbon as a negative electrode active material.

非水電解液二次電池は様々なものが実用化されており、その一つとしてリチウムイオン二次電池がある。リチウムイオン二次電池は、小型軽量で且つ高容量であることから携帯電子機器や、携帯通信機器、電動アシスト自転車、電動工具などに用いられるようになってきている。   Various non-aqueous electrolyte secondary batteries have been put into practical use, and one of them is a lithium ion secondary battery. Lithium ion secondary batteries are small, light, and have a high capacity, so that they are used in portable electronic devices, portable communication devices, electric assist bicycles, electric tools, and the like.

非水電解液二次電池は正極活物質、正極結着剤、導電助剤を含む正極層を正極集電体上に形成した正極と、負極活物質、負極結着剤を含む負極層を負極集電体上に形成した負極とをセパレータを介して積層あるいは巻回した積層体を金属ケースあるいはラミネート外装体に収納した構造となっている。   The non-aqueous electrolyte secondary battery includes a positive electrode in which a positive electrode layer including a positive electrode active material, a positive electrode binder, and a conductive additive is formed on a positive electrode current collector, and a negative electrode layer including a negative electrode active material and a negative electrode binder. A laminated body obtained by laminating or winding a negative electrode formed on a current collector via a separator is housed in a metal case or a laminated exterior body.

炭素繊維織布はシート形状を有し、また半金属的な導電性を有する。そのため金属箔集電体の代わりに使用することが出来る（特許文献１、特許文献２など）。また活物質として炭素を用いる二次電池用電極においては活物質としても作用するので容量密度の点で有利である。しかし金属集電体を用いた電極と比べて集電性能が劣るため、レート特性の面では不利である。また、特許文献３には炭素繊維織布に電極スラリーを塗布したものを金属箔集電体に摺接させる電極構造が開示されている。   The carbon fiber woven fabric has a sheet shape and has semi-metallic conductivity. Therefore, it can be used instead of the metal foil current collector (Patent Document 1, Patent Document 2, etc.). In addition, a secondary battery electrode using carbon as an active material is advantageous in terms of capacity density because it functions as an active material. However, the current collection performance is inferior to that of an electrode using a metal current collector, which is disadvantageous in terms of rate characteristics. Patent Document 3 discloses an electrode structure in which a carbon fiber woven fabric coated with an electrode slurry is brought into sliding contact with a metal foil current collector.

特開平７−６５８６２号公報Japanese Patent Laid-Open No. 7-65862 特開平８−２１３０４９号公報JP-A-8-213049 特開２００２−６３９３８号公報JP 2002-63938 A

すでに一部説明したように、炭素繊維織布はシート形状を有し、また半金属的な導電性を有する。そのため金属箔集電体の代用として使用することが出来るだけでなく、リチウムイオン二次電池において炭素繊維織布の集電体は活物質としても作用するため容量密度の点で有利である。しかし炭素繊維織布は金属集電体と比較すると電気伝導性が低く集電体性能が劣るため、レート特性の面で不利である。   As already explained in part, the carbon fiber woven fabric has a sheet shape and has semi-metallic conductivity. Therefore, not only can it be used as a substitute for the metal foil current collector, but the current collector of the carbon fiber woven fabric also acts as an active material in a lithium ion secondary battery, which is advantageous in terms of capacity density. However, carbon fiber woven fabrics are disadvantageous in terms of rate characteristics because they have lower electrical conductivity and inferior current collector performance than metal current collectors.

そこで、本発明の課題は、体積エネルギー密度が高く、且つレート特性に優れた非水電解液二次電池を提供することにある。   Accordingly, an object of the present invention is to provide a nonaqueous electrolyte secondary battery having a high volumetric energy density and excellent rate characteristics.

本発明は、前記課題を解決するため、炭素繊維織布にＣｕ繊維を織り込んだ織布を用いることで、集電性能を向上させた。このとき電極層の内部に立体的に張り巡らされたＣｕ繊維が効率的に集電しレート特性の優れた負極が得られることを見出した。   In order to solve the above problems, the present invention improves the current collecting performance by using a woven fabric in which Cu fibers are woven into a carbon fiber woven fabric. At this time, it was found that Cu fibers stretched three-dimensionally inside the electrode layer were efficiently collected to obtain a negative electrode having excellent rate characteristics.

本発明の非水電解液二次電池は、負極および正極をセパレータを介して積層または巻回し外装体に収納した非水電解液二次電池において、負極集電体に炭素繊維とＣｕ繊維からなる織布を用い、前記織布に含まれるＣｕ繊維の比率が織布全体の５質量％以上５０質量％以下であり、前記炭素繊維の（１１０）面が前記繊維の側部表面に露出することを特徴とする。 The non-aqueous electrolyte secondary battery of the present invention is a non-aqueous electrolyte secondary battery in which a negative electrode and a positive electrode are stacked or wound via a separator and housed in an exterior body, and the negative electrode current collector is composed of carbon fibers and Cu fibers. Using a woven fabric, the ratio of Cu fibers contained in the woven fabric is 5% by mass or more and 50% by mass or less of the entire woven fabric, and the (110) surface of the carbon fiber is exposed on the side surface of the fiber. It is characterized by.

前記炭素繊維は、（００２）面内に繊維の長さ方向があるように配向しているとよい。 The carbon fibers are preferably oriented so that the length direction of the fibers is in the (002) plane .

前記織布を用いた負極集電体に黒鉛を主体としてなる電極スラリーを塗布・含浸するとよい。   The negative electrode current collector using the woven fabric may be coated and impregnated with an electrode slurry mainly composed of graphite.

本発明においては、炭素繊維を用いた負極においてＣｕ繊維を共に織り込み、織布の間隙に導電助剤、黒鉛粉末、結着剤からなる混合物を充填することにより、レート特性、体積容量密度に優れた二次電池が得られる。具体的には電極シート内に三次元的に張り巡らされた炭素繊維とＣｕ繊維が効率的に集電し、また織布に織り込まれたＣｕ繊維と導電助剤など、結着剤以外の全てが負極の容量に寄与するため非常に高い体積容量密度の負極が得られる。   In the present invention, Cu fibers are woven together in a negative electrode using carbon fibers, and a mixture of a conductive additive, graphite powder, and a binder is filled in the gap of the woven fabric, so that it has excellent rate characteristics and volume capacity density. A secondary battery is obtained. Specifically, carbon fibers and Cu fibers stretched three-dimensionally within the electrode sheet efficiently collect current, and Cu fibers and conductive aids woven into the woven fabric all other than the binder Contributes to the capacity of the negative electrode, so that a negative electrode having a very high volume capacity density can be obtained.

本発明によれば、負極活物質に炭素を用いた非水電解液二次電池において、負極集電体にはＣｕ繊維を共に織り込んだ炭素繊維織布を用いることで優れたレート特性を実現することができる。また集電体織布を構成する炭素自身が容量に寄与するため体積容量効率の高い負極を有する非水電解液二次電池を提供することができる。   According to the present invention, in a non-aqueous electrolyte secondary battery using carbon as a negative electrode active material, excellent rate characteristics are realized by using a carbon fiber woven fabric in which Cu fibers are woven together as a negative electrode current collector. be able to. Further, since the carbon itself constituting the current collector woven fabric contributes to the capacity, it is possible to provide a non-aqueous electrolyte secondary battery having a negative electrode with high volumetric capacity efficiency.

本発明の非水電解液二次電池は、負極活物質と負極結着剤を含む負極層を炭素繊維・Ｃｕ繊維織布（炭素繊維織布にＣｕ繊維を織り込んだ織布）に塗布、充填した負極と、正極活物質、正極結着剤、導電助剤を含む正極層を正極集電体上に形成した正極とをセパレータを介して積層あるいは巻回した積層体を外装体に収納して非水電解液あるいはポリマー電解質を注入したのち封止して製造する。上記負極において織布を覆う負極層（織布の外側にある負極層）の厚みは６０μｍ以下であることが望ましい。本発明において織布を覆う電極層の厚みが６０μｍを超える場合、Ｃｕ金属から電極表面の活物質までの距離が従来の負極での値を超えレート特性における優位性が失われる。なぜなら、負極層の体積抵抗率が２〜３Ω／ｃｍであるのに対してＣｕは１．７×１０−８Ω／ｃｍと圧倒的に低いため、Ｃｕ金属から負極層表面までの距離が電極抵抗に対して支配的となるからである。 In the non-aqueous electrolyte secondary battery of the present invention, a negative electrode layer containing a negative electrode active material and a negative electrode binder is coated and filled on a carbon fiber / Cu fiber woven fabric (a woven fabric in which Cu fibers are woven into a carbon fiber woven fabric). A laminated body obtained by laminating or winding a negative electrode and a positive electrode in which a positive electrode layer including a positive electrode active material, a positive electrode binder, and a conductive auxiliary agent is formed on a positive electrode current collector through a separator is housed in an outer package. A non-aqueous electrolyte or polymer electrolyte is injected and then sealed. The thickness of the negative electrode layer (negative electrode layer outside the woven fabric) covering the woven fabric in the negative electrode is preferably 60 μm or less. In the present invention, when the thickness of the electrode layer covering the woven fabric exceeds 60 μm, the distance from the Cu metal to the active material on the electrode surface exceeds the value in the conventional negative electrode, and the superiority in rate characteristics is lost. Because the negative electrode layer has a volume resistivity of 2 to 3 Ω / cm, while Cu is overwhelmingly low at 1.7 × 10 −8 Ω / cm, the distance from the Cu metal to the negative electrode layer surface is the electrode This is because it becomes dominant over the resistance.

本発明の非水電解液二次電池において織布を構成する炭素繊維について、図１と図２を参照して説明する。図１は本発明に用いる炭素繊維の例を示す模式図であり、１１は繊維の長さ方向ベクトルである。また、１２は（００２）面内の直交ベクトルであり、繊維の長さ方向を含むように広がる（００２）面を、その面内にある２つのベクトルで示している。さらに、１３は（１１０）面内の直交ベクトルであり、繊維の側部表面に（１１０）面が露出する様子を表している。他方、図２は本発明で使用できない炭素繊維の例を示す模式図であり、２１は（１１０）面内の直交ベクトルであり、繊維長さ方向の端面に（１１０）面が露出する様子を示している。また、２２は（００２）面内の直交ベクトルであり、繊維の側部表面を覆う（００２）面を示している。   The carbon fibers constituting the woven fabric in the nonaqueous electrolyte secondary battery of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram showing an example of a carbon fiber used in the present invention, and 11 is a length direction vector of the fiber. Reference numeral 12 denotes an orthogonal vector in the (002) plane, and the (002) plane spreading so as to include the length direction of the fiber is indicated by two vectors in the plane. Further, 13 is an orthogonal vector in the (110) plane, and represents a state in which the (110) plane is exposed on the side surface of the fiber. On the other hand, FIG. 2 is a schematic diagram showing an example of carbon fiber that cannot be used in the present invention, 21 is an orthogonal vector in the (110) plane, and the state in which the (110) plane is exposed at the end face in the fiber length direction. Show. Reference numeral 22 denotes an orthogonal vector in the (002) plane, which indicates the (002) plane covering the side surface of the fiber.

本発明では、図１のように、繊維の長さ方向に（００２）面の広がった炭素繊維を用いることが出来る。その理由は次のとおりである。炭素は結晶の（００２）面の面内方向に半金属的な電気伝導性を示し、これと垂直な方向については半導体である。（００２）面を繊維の長さ方向に配向させることで織布の面方向における導電性を確保することが出来る。さらに繊維の側部表面には（１１０）面を露出している炭素繊維を用いることが出来る。そうすると、（１１０）面からＬｉの挿入が起こる。   In the present invention, as shown in FIG. 1, a carbon fiber having a (002) plane spread in the length direction of the fiber can be used. The reason is as follows. Carbon exhibits semi-metallic electrical conductivity in the in-plane direction of the (002) plane of the crystal, and is a semiconductor in the direction perpendicular thereto. By orienting the (002) plane in the length direction of the fiber, conductivity in the plane direction of the woven fabric can be ensured. Further, carbon fibers with exposed (110) faces can be used on the side surfaces of the fibers. Then, Li insertion occurs from the (110) plane.

しかし、図２のように、繊維側部表面を（００２）面が完全に覆い長さ方向の端面のみに（１１０）面を露出した炭素繊維は望ましくない。その理由は次のとおりである。リチウムイオン二次電池において炭素へのＬｉの挿入反応を負極反応として利用している。炭素へのＬｉの挿入は（００２）面と垂直な（１１０）面から起こるため織布を構成する炭素繊維が容量に寄与するには繊維表面に（１１０）面を露出していることが望ましいからである。   However, as shown in FIG. 2, a carbon fiber in which the (002) plane completely covers the fiber side surface and the (110) plane is exposed only on the end face in the length direction is not desirable. The reason is as follows. Lithium ion secondary batteries use Li insertion into carbon as a negative electrode reaction. Since insertion of Li into carbon occurs from the (110) plane perpendicular to the (002) plane, it is desirable that the (110) plane is exposed on the fiber surface in order for the carbon fibers constituting the woven fabric to contribute to capacity. Because.

繊維径は５〜５０μｍの炭素繊維を用いることが出来る。Ｃｕ繊維としては径が５〜５０μｍのものを用いることが出来る。Ｃｕ繊維の比率は５質量％以上、５０質量％以下であるとよい。その理由は次のとおりである。５質量％未満であると従来の金属箔集電体上に電極層を形成してなるものと比較してレート特性が劣る。また５０質量％を超える場合、従来の金属箔集電体上に電極層を形成してなるものと比較して体積容量効率が劣るからである。   Carbon fiber having a fiber diameter of 5 to 50 μm can be used. Cu fibers having a diameter of 5 to 50 μm can be used. The ratio of Cu fibers is preferably 5% by mass or more and 50% by mass or less. The reason is as follows. When the content is less than 5% by mass, the rate characteristics are inferior to those obtained by forming an electrode layer on a conventional metal foil current collector. Moreover, when it exceeds 50 mass%, it is because volume capacity efficiency is inferior compared with what forms an electrode layer on the conventional metal foil collector.

負極活物質としては人造黒鉛、天然黒鉛を用いることが出来る。たとえば負極活物質、結着剤、カーボンブラックのような導電助剤をＮＭＰ（Ｎ−メチル−２−ピロリドン）のような溶剤中に分散させ、スラリーを調製し、負極集電体上に直接塗布、乾燥し圧縮することにより負極層を形成する。   Artificial graphite and natural graphite can be used as the negative electrode active material. For example, a conductive additive such as a negative electrode active material, a binder, or carbon black is dispersed in a solvent such as NMP (N-methyl-2-pyrrolidone) to prepare a slurry, which is directly applied onto the negative electrode current collector. The negative electrode layer is formed by drying and compressing.

本発明の非水電解液二次電池で用いることのできる正極活物質として、ＬｉＭＯ２（ただしＭは、少なくとも一つの遷移金属を表す。）を単独あるいは複数種を混合したものを用いることができる。たとえば結着剤、正極活物質、カーボンブラックのような導電助剤をＮＭＰのような溶剤中に分散させ、スラリーを調製し、集電体上に直接塗布、乾燥し圧縮することにより正極層を形成する。 As the positive electrode active material that can be used in the non-aqueous electrolyte secondary battery of the present invention, LiMO 2 (wherein M represents at least one transition metal) can be used alone or a mixture of a plurality of types. . For example, a conductive agent such as a binder, a positive electrode active material, and carbon black is dispersed in a solvent such as NMP to prepare a slurry, which is directly applied onto a current collector, dried and compressed to form a positive electrode layer. Form.

セパレータとしてはポリプロピレン、ポリエチレン等のポリオレフィン樹脂、フッ素樹脂等の多孔性フィルムなどが使用できる。   As the separator, a polyolefin resin such as polypropylene or polyethylene, a porous film such as a fluororesin, or the like can be used.

電解液としては、プロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、ビニレンカーボネート等の環状カーボネート類、ジメチルカーボネート、ジエチルカーボネート、ジメチルカーボネート、エチルメチルカーボネート、ジプロピルカーボネート等の鎖状カーボネート類、ギ酸メチル、酢酸メチル、プロピオン酸エーテル等の脂肪カルボン酸エステル類、γ−ブチロラクトン等のγ−ラクトン類、１，２−ジエトキシエタン、エトキシメトキシエタン等の鎖状エーテル類、テトラヒドロフラン、２−メチルテトラヒドロフラン等の環状エーテル類、ジメチルスルホキシド、１，３−ジオキシラン、ホルムアミド、アセトアミド、ジメチルホルムアミド、ジオキソラン、アセトニトリル、プロピルニトリル、ニトロメタン、エチルモノグライム、リン酸トリエステル、トリメトキシメタン、ジオキソラン誘導体、スルホラン、メチルスルホラン、１，３−ジメチル−２−イミダゾノジノン、３−メチル−２−オキサゾリジノン、プロピレンカーボネート誘導体、テトラヒドロフラン誘導体、ジエチルエーテル等の非プロトン性溶媒一種、あるいは二種以上を混合して使用し、これらの有機溶媒に溶解するリチウム塩を溶解させる。リチウム塩としては、たとえばＬｉＰＦ６、ＬｉＡｓＦ６、ＬｉＡｌＣｌ４、ＬｉＣｌＯ４、ＬｉＢＦ４、ＬｉＳｂＦ６、Ｌｉ（ＣＦ３ＳＯ２）２、ＬｉＢｒ、ＬｉＣｌ、低脂肪酸カルボン酸リチウム、イミド類が挙げられる。また、電解液に代えてポリマー電解質を用いてもよい。 Examples of the electrolyte include cyclic carbonates such as propylene carbonate, ethylene carbonate, butylene carbonate, and vinylene carbonate, chain carbonates such as dimethyl carbonate, diethyl carbonate, dimethyl carbonate, ethyl methyl carbonate, and dipropyl carbonate, methyl formate, and methyl acetate. , Fatty carboxylic acid esters such as propionate ether, γ-lactones such as γ-butyrolactone, chain ethers such as 1,2-diethoxyethane and ethoxymethoxyethane, cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran , Dimethyl sulfoxide, 1,3-dioxirane, formamide, acetamide, dimethylformamide, dioxolane, acetonitrile, propylnitrile, nitromethane , Ethyl monoglyme, phosphoric acid triester, trimethoxymethane, dioxolane derivative, sulfolane, methyl sulfolane, 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidinone, propylene carbonate derivative, tetrahydrofuran derivative, diethyl An aprotic solvent such as ether or a mixture of two or more aprotic solvents is used to dissolve the lithium salt dissolved in these organic solvents. Examples of the lithium salt include LiPF 6 , LiAsF 6 , LiAlCl 4 , LiClO 4 , LiBF 4 , LiSbF 6 , Li (CF 3 SO 2 ) 2 , LiBr, LiCl, low fatty acid carboxylic acid lithium, and imides. Further, a polymer electrolyte may be used instead of the electrolytic solution.

以下、本発明を実施例に基づきさらに具体的に説明する。   Hereinafter, the present invention will be described more specifically based on examples.

（実施例１）
本発明の電極断面を模式的に示す図３を参照しながら説明する。負極活物質として人造黒鉛を９３重量部、導電助剤としてカーボンブラックを２重量部、結着剤としてポリフッ化ビニリデン（以下ＰＶＤＦとする）を５重量部となるように、結着剤を溶解したＮＭＰ溶液に混合してスラリーを調製し、このスラリー（電極スラリー３５）を、厚さ１２０μｍの炭素繊維・Ｃｕ繊維織布（炭素繊維３１、３３とＣｕ繊維３２、３４の織布）の両面から均一に塗布、含浸して負極層を得た。このとき電極の厚みが１３０μｍとなるようにスラリーの塗布量を調整した。ところで、上記織布におけるＣｕ繊維３２、３４の割合、すなわち、炭素繊維とＣｕ繊維の全質量に対するＣｕ繊維の質量の割合は５質量％とした。 Example 1
Description will be made with reference to FIG. 3 schematically showing a cross section of the electrode of the present invention. The binder was dissolved so that 93 parts by weight of artificial graphite as the negative electrode active material, 2 parts by weight of carbon black as the conductive auxiliary, and 5 parts by weight of polyvinylidene fluoride (hereinafter referred to as PVDF) as the binder were used. The slurry (electrode slurry 35) is mixed with the NMP solution, and this slurry (electrode slurry 35) is applied to both sides of a 120 μm thick carbon fiber / Cu fiber woven fabric (woven fabric of carbon fibers 31, 33 and Cu fibers 32, 34). The negative electrode layer was obtained by uniformly applying and impregnating. At this time, the amount of slurry applied was adjusted so that the thickness of the electrode was 130 μm. By the way, the ratio of the Cu fibers 32 and 34 in the woven fabric, that is, the ratio of the mass of the Cu fibers to the total mass of the carbon fibers and the Cu fibers was 5 mass%.

正極活物質としてはＬｉＣｏＯ２を用いた。正極活物質を９５重量部、導電助剤としてカーボンブラックを２重量部、結着剤としてＰＶＤＦを３重量部となるように、結着剤を溶解したＮＭＰ溶液に混合してスラリーを調製し、このスラリーを厚さ１５μｍのアルミ製の集電体の両面に均一に塗布して正極層を形成した。 LiCoO 2 was used as the positive electrode active material. A slurry was prepared by mixing the NMP solution in which the binder was dissolved, so that the positive electrode active material was 95 parts by weight, the carbon black as the conductive auxiliary agent was 2 parts by weight, and the PVDF as the binder was 3 parts by weight. This slurry was uniformly applied on both surfaces of a 15 μm thick aluminum current collector to form a positive electrode layer.

電解液は１モル／ｌの濃度にＬｉＰＦ６を溶解させたエチレンカーボネート（ＥＣ）とジエチルカーボネート（ＤＥＣ）の混合溶媒（混合容積比：ＥＣ／ＤＥＣ＝３０／７０）を用いた。また、セパレータとしては厚さ２０μｍの多孔性ポリエチレンフィルムを用いた。 As the electrolyte, a mixed solvent of ethylene carbonate (EC) and diethyl carbonate (DEC) in which LiPF 6 was dissolved at a concentration of 1 mol / l (mixing volume ratio: EC / DEC = 30/70) was used. As the separator, a porous polyethylene film having a thickness of 20 μm was used.

上述した正極層、負極層、およびセパレータを積層した積層体をラミネート外装体に収納して電解液を注液したのち封止して非水電解液二次電池を組み立てた。   The laminated body in which the positive electrode layer, the negative electrode layer, and the separator described above were stacked was housed in a laminate outer package, poured with an electrolytic solution, and sealed to assemble a non-aqueous electrolyte secondary battery.

また、Ｌｉ金属を対極として上述した負極、セパレータ、電解液を用いて、コイン型電池（ＣＲ２０３２）を組み立てた。   Further, a coin-type battery (CR2032) was assembled using the above-described negative electrode, separator, and electrolytic solution using Li metal as a counter electrode.

（実施例２）
炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率を１０質量％としたほかは実施例１と同様に非水電解液二次電池、コイン型電池を組み立てた。 (Example 2)
A non-aqueous electrolyte secondary battery and a coin-type battery were assembled in the same manner as in Example 1 except that the ratio of the Cu fiber in the carbon fiber / Cu fiber woven fabric was 10% by mass.

（実施例３）
炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率を２０質量％としたほかは実施例１と同様に非水電解液二次電池、コイン型電池を組み立てた。 (Example 3)
A non-aqueous electrolyte secondary battery and a coin-type battery were assembled in the same manner as in Example 1 except that the ratio of the Cu fiber in the carbon fiber / Cu fiber woven fabric was 20% by mass.

（実施例４）
炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率を５０質量％としたほかは実施例１と同様に非水電解液二次電池、コイン型電池を組み立てた。 Example 4
A non-aqueous electrolyte secondary battery and a coin-type battery were assembled in the same manner as in Example 1 except that the ratio of the Cu fibers in the carbon fiber / Cu fiber woven fabric was 50% by mass.

（比較例１）
炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率を０質量％としたほかは実施例１と同様に非水電解液二次電池、コイン型電池を組み立てた。 (Comparative Example 1)
A non-aqueous electrolyte secondary battery and a coin-type battery were assembled in the same manner as in Example 1 except that the ratio of the Cu fibers in the carbon fiber / Cu fiber woven fabric was 0 mass%.

（比較例２）
負極活物質として人造黒鉛を９３重量部、導電助剤としてカーボンブラックを２重量部、結着剤を５重量部となるように、結着剤を溶解したＮＭＰ溶液に混合してスラリーを調製し、このスラリーを厚さ１０μｍの銅製の集電体の両面にドクターブレード法により塗布して負極層を得た。このとき電極の厚みが１３０μｍとなるようにスラリーの塗布量を調整した。そのほかは実施例１と同様に非水電解液二次電池、コイン型電池を組み立てた。 (Comparative Example 2)
A slurry was prepared by mixing the NMP solution in which the binder was dissolved so that 93 parts by weight of artificial graphite as the negative electrode active material, 2 parts by weight of carbon black as the conductive auxiliary agent, and 5 parts by weight of the binder were mixed. The slurry was applied to both sides of a copper current collector having a thickness of 10 μm by the doctor blade method to obtain a negative electrode layer. At this time, the amount of slurry applied was adjusted so that the thickness of the electrode was 130 μm. Other than that, a non-aqueous electrolyte secondary battery and a coin-type battery were assembled in the same manner as in Example 1.

実施例１〜４、比較例１、２で組み立てた非水電解液二次電池について０．２Ｃ、２．０Ｃの放電容量を測定しその比からそれぞれのレート特性を比較した。容量測定は充電電圧４．２Ｖ（充電条件：電流１．０Ｃ、２．５時間、２０℃）、放電電圧３．０Ｖ（放電条件：電流０．２Ｃ、１．０Ｃ、２０℃）にて実施した。また実施例１〜４、比較例１、２で組み立てたコイン型電池については１／４０Ｃ放電容量を測定した。容量測定は充電電圧４．３Ｖ（充電条件：電流１／４０Ｃ、２０℃）、放電電圧０Ｖ（放電条件：電流１／４０Ｃ、２０℃）にて実施した。   The nonaqueous electrolyte secondary batteries assembled in Examples 1 to 4 and Comparative Examples 1 and 2 were measured for discharge capacities of 0.2 C and 2.0 C, and the rate characteristics were compared based on the ratios. Capacity measurement was performed at a charge voltage of 4.2 V (charge condition: current 1.0 C, 2.5 hours, 20 ° C.) and a discharge voltage of 3.0 V (discharge condition: current 0.2 C, 1.0 C, 20 ° C.). did. Moreover, about the coin-type battery assembled in Examples 1-4 and Comparative Examples 1 and 2, 1 / 40C discharge capacity was measured. The capacity measurement was performed at a charging voltage of 4.3 V (charging condition: current 1/40 C, 20 ° C.) and a discharging voltage of 0 V (discharging condition: current 1/40 C, 20 ° C.).

表１に実施例１〜４、比較例１、２で組み立てた非水電解液二次電池について０．２Ｃ放電容量に対する２．０Ｃ放電容量の比率、およびコイン型電池の放電容量から算出した負極の体積容量密度を示す。   The negative electrode calculated from the ratio of the 2.0 C discharge capacity to the 0.2 C discharge capacity and the discharge capacity of the coin type battery for the nonaqueous electrolyte secondary batteries assembled in Examples 1 to 4 and Comparative Examples 1 and 2 in Table 1 The volume capacity density of is shown.

図４に炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率（質量％）を横軸に、レート特性を縦軸にしたグラフを示す。また図５に炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の比率（質量％）を横軸に、負極の体積容量密度（ｍＡｈ／ｃｍ３）を縦軸にしたグラフを示す。 FIG. 4 is a graph in which the horizontal axis represents the ratio (mass%) of Cu fibers in the carbon fiber / Cu fiber woven fabric, and the vertical axis represents rate characteristics. FIG. 5 shows a graph in which the ratio (mass%) of Cu fibers in the carbon fiber / Cu fiber woven fabric is plotted on the horizontal axis and the volume capacity density (mAh / cm 3 ) of the negative electrode is plotted on the vertical axis.

Figure 0005252535
Figure 0005252535

図４から分かるように、織布全体に対するＣｕ繊維の比率が５質量％以上５０質量％以下のときに、比較例１（Ｃｕ繊維を含まないもの）および比較例２（銅製の集電体を用いたもの）を超えるレート特性が得られた。また、図５から分かるように、織布全体に対するＣｕ繊維の比率が５質量％以上５０質量％以下のときに、比較例２を超える体積容量密度が得られた。   As can be seen from FIG. 4, when the ratio of Cu fibers to the entire woven fabric is 5% by mass or more and 50% by mass or less, Comparative Example 1 (without Cu fibers) and Comparative Example 2 (copper collectors) A rate characteristic exceeding that used) was obtained. Further, as can be seen from FIG. 5, a volume capacity density exceeding Comparative Example 2 was obtained when the ratio of Cu fibers to the entire woven fabric was 5 mass% or more and 50 mass% or less.

本発明に用いる炭素繊維の例を示す模式図。The schematic diagram which shows the example of the carbon fiber used for this invention. 本発明では使用できない炭素繊維の例を示す模式図。The schematic diagram which shows the example of the carbon fiber which cannot be used in this invention. 本発明の電極を示す模式的断面図。The typical sectional view showing the electrode of the present invention. レート特性と炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の割合との関係を示す図。The figure which shows the relationship between a rate characteristic and the ratio of Cu fiber in a carbon fiber and Cu fiber woven fabric. 負極の体積容量密度と炭素繊維・Ｃｕ繊維織布におけるＣｕ繊維の割合との関係を示す図。The figure which shows the relationship between the volume capacity density of a negative electrode, and the ratio of Cu fiber in a carbon fiber and Cu fiber woven fabric.

符号の説明Explanation of symbols

１１ 繊維の長さ方向ベクトル
１２、２２ （００２）面内の直交ベクトル
１３ （１１０）面内の直交ベクトル
２１ （１１０）面内の直交ベクトル
３１、３３ 炭素繊維
３２、３４ Ｃｕ繊維
３５ 電極スラリー 11 Fiber length direction vector 12, 22 Orthogonal vector 13 in (002) plane Orthogonal vector 21 in (110) plane Orthogonal vector 31, 33 in (110) plane Carbon fiber 32, 34 Cu fiber 35 Electrode slurry

Claims (3)

負極および正極をセパレータを介して積層または巻回し外装体に収納した非水電解液二次電池において、負極集電体に炭素繊維とＣｕ繊維からなる織布を用い、前記織布に含まれるＣｕ繊維の比率が織布全体の５質量％以上５０質量％以下であり、前記炭素繊維の（１１０）面が前記繊維の側部表面に露出することを特徴とする非水電解液二次電池。 In a non-aqueous electrolyte secondary battery in which a negative electrode and a positive electrode are stacked or wound via a separator and housed in an exterior body, a woven fabric made of carbon fibers and Cu fibers is used for the negative electrode current collector, and Cu contained in the woven fabric The non-aqueous electrolyte secondary battery , wherein a ratio of the fibers is 5% by mass or more and 50% by mass or less of the entire woven fabric, and a (110) surface of the carbon fiber is exposed on a side surface of the fiber . 前記炭素繊維は、（００２）面内に繊維の長さ方向があるように配向していることを特徴とする請求項１記載の非水電解液二次電池。 The non-aqueous electrolyte secondary battery according to claim 1 , wherein the carbon fibers are oriented so that the length direction of the fibers is in a (002) plane . 前記織布を用いた負極集電体に黒鉛を主体としてなる電極スラリーを塗布・含浸したことを特徴とする請求項１または２記載の非水電解液二次電池。   The non-aqueous electrolyte secondary battery according to claim 1 or 2, wherein an electrode slurry mainly composed of graphite is applied and impregnated on the negative electrode current collector using the woven fabric.
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