JP2005174779A - Lithium ion secondary cell - Google Patents

Lithium ion secondary cell Download PDF

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JP2005174779A
JP2005174779A JP2003414244A JP2003414244A JP2005174779A JP 2005174779 A JP2005174779 A JP 2005174779A JP 2003414244 A JP2003414244 A JP 2003414244A JP 2003414244 A JP2003414244 A JP 2003414244A JP 2005174779 A JP2005174779 A JP 2005174779A
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separator
negative electrode
ion secondary
lithium ion
positive electrode
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Takao Kuromiya
孝雄 黒宮
Kazunori Kubota
和典 久保田
Tetsuya Hayashi
徹也 林
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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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

Abstract

<P>PROBLEM TO BE SOLVED: To improve the lifetime property and reliability of a lithium ion secondary cell. <P>SOLUTION: A power generation element 1 is formed with a belt-like anode 1b formed of a first plied timber layer 21 on both sides of a first collector 20, a belt-like cathode 1a with a second plied timber layer 11 formed on both sides of a second collector 10 and a belt-like separator 1c arranged so that the cathode 1a and the anode 1b do not contact each other onto both sides of the anode 1b or both sides the cathode 1a. In a lithium ion secondary cell having a structure winding the power generation element 1 or laminating a plurality of the power generation elements 1, both two of the first plied timber layers 21 on both sides of the first collector 20 or two of the second plied timber layers 11 on both sides of the second collector 10 are covered with a separator 1c from its one end part A to the other end part B, and furthermore, both of them are adhered with the separator 1c from its one end part A to the other end part B. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、リチウムイオン二次電池に関する。例えば、リチウムイオン二次電池の発電要素の構造に関する。   The present invention relates to a lithium ion secondary battery. For example, the present invention relates to the structure of a power generation element of a lithium ion secondary battery.

従来のリチウムイオン二次電池には、負極の始終端部がはみ出して内部短絡を生じることのないようにセパレータの端部を固着しているものがあった（例えば、特許文献１参照）。図５は、特許文献１に提示されているリチウムイオン二次電池の発電要素１の斜視図を示しており、図６は、その始端部と終端部を含む長手方向の断面図を示している。   In some conventional lithium ion secondary batteries, the end of the separator is fixed so that the start / end of the negative electrode does not protrude and cause an internal short circuit (see, for example, Patent Document 1). FIG. 5 shows a perspective view of the power generation element 1 of the lithium ion secondary battery presented in Patent Document 1, and FIG. 6 shows a longitudinal sectional view including the start end and the end. .

図５および図６で、発電要素１は正極１ａと負極１ｂとセパレータ１ｃ、１ｄで構成されている。２枚のセパレータ１ｃと１ｄは、始端部Ａと終端部Ｂで互いに固着されている。   5 and 6, the power generating element 1 is composed of a positive electrode 1a, a negative electrode 1b, and separators 1c and 1d. The two separators 1c and 1d are fixed to each other at the start end A and the end B.

充放電時の発熱によって正極１ａと負極１ｂは長手方向に伸縮するが、このように２枚のセパレータ１ｃと１ｄの始端部Ａおよび終端部Ｂを固着していることで、負極１ｂが始端部Ａまたは終端部Ｂにおいて正極１ａと短絡することを防止している。
特開平２０００−１７３６４２号公報 The positive electrode 1a and the negative electrode 1b expand and contract in the longitudinal direction due to heat generation during charging and discharging, but the negative electrode 1b becomes the starting end portion by fixing the starting end A and the terminal end B of the two separators 1c and 1d in this way. A or terminal B is prevented from being short-circuited with the positive electrode 1a.
Japanese Patent Laid-Open No. 2000-173642

しかしながら、上記の特許文献１に示される構成では、正極１ａと負極１ｂとの短絡は生じないが、図６に示すようにセパレータ１ｃ、１ｄと負極１ｂは密着していないので、充放電の繰り返しによってセパレータ１ｃ、１ｄと負極１ｂの間隙に金属リチウムが析出してしまう。これによって、リチウムイオン二次電池の寿命特性および信頼性に影響を与えるという課題を有していた。   However, although the short circuit between the positive electrode 1a and the negative electrode 1b does not occur in the configuration shown in Patent Document 1, the separators 1c and 1d and the negative electrode 1b are not in close contact as shown in FIG. As a result, metallic lithium is deposited in the gap between the separators 1c and 1d and the negative electrode 1b. Thus, there is a problem of affecting the life characteristics and reliability of the lithium ion secondary battery.

また、図６に示す発電要素１は、２枚のセパレータ１ｃと１ｄの始終端部が固着されている構成であるが、２枚のセパレータ１ｃと１ｄの始終端部が固着されていない構成であっても、セパレータ１ｃ、１ｄと負極１ｂは密着していないので、セパレータ１ｃ、１ｄと負極１ｂの間隙に金属リチウムが析出するという、同様の課題が生じる。   Further, the power generating element 1 shown in FIG. 6 has a configuration in which the start and end portions of the two separators 1c and 1d are fixed, but the configuration in which the start and end portions of the two separators 1c and 1d are not fixed. Even if it exists, since the separators 1c and 1d and the negative electrode 1b are not closely_contact | adhered, the same subject that metallic lithium precipitates in the gap | interval of the separators 1c and 1d and the negative electrode 1b arises.

本発明は、上記従来の課題を解決するもので、寿命特性および信頼性に優れたリチウムイオン二次電池を提供することを目的とする。   The present invention solves the above-described conventional problems, and an object of the present invention is to provide a lithium ion secondary battery having excellent life characteristics and reliability.

上述した課題を解決するために、第１の本発明は、
第１の集電体の両面に第１の合材層が形成された帯状の負極と、第２の集電体の両面に第２の合材層が形成された帯状の正極と、前記負極の両面または前記正極の両面に前記正極と前記負極が接触しないように配置される帯状のセパレータとで発電要素を形成しており、一の前記発電要素が捲回された構成、または、複数の前記発電要素が積層された構成を有するリチウムイオン二次電池において、
前記第１の集電体の両面の２つの前記第１の合材層または前記第２の集電体の両面の２つの前記第２の合材層は、その一方の端部から他方の端部に至るまで前記セパレータで覆われており、さらに、いずれも、前記一方の端部から前記他方の端部に至るまで前記セパレータと接着している、リチウムイオン二次電池である。 In order to solve the above-described problem, the first aspect of the present invention provides:
A strip-shaped negative electrode in which a first composite material layer is formed on both surfaces of a first current collector, a strip-shaped positive electrode in which a second composite material layer is formed on both surfaces of a second current collector, and the negative electrode A power generation element is formed by a strip-shaped separator disposed so that the positive electrode and the negative electrode do not contact each other on both surfaces of the positive electrode or the positive electrode, and a configuration in which one power generation element is wound, or a plurality of In a lithium ion secondary battery having a configuration in which the power generation elements are stacked,
The two first composite layers on both sides of the first current collector or the two second composite layers on both sides of the second current collector are arranged from one end to the other end. The lithium-ion secondary battery is covered with the separator until reaching the portion, and both are bonded to the separator from the one end to the other end.

第２の本発明は、
前記第１の合材層または前記第２の合材層と接着している部分の前記セパレータの厚さは実質上均一である、第１の本発明のリチウムイオン二次電池である。 The second aspect of the present invention
In the lithium ion secondary battery according to the first aspect of the present invention, the thickness of the separator in the portion bonded to the first composite material layer or the second composite material layer is substantially uniform.

第３の本発明は、
前記セパレータは無機酸化物を含有している、第１または第２の本発明のリチウムイオン二次電池である。 The third aspect of the present invention provides
The separator is the lithium ion secondary battery according to the first or second aspect of the present invention, which contains an inorganic oxide.

第４の本発明は、
前記セパレータの前記無機酸化物の含有量は９０重量％以上である、第３の本発明のリチウムイオン二次電池である。 The fourth invention relates to
The content of the inorganic oxide in the separator is 90% by weight or more, and the lithium ion secondary battery according to the third aspect of the present invention.

第５の本発明は、
前記負極の帯状の両辺部または前記正極の帯状の両辺部は、前記正極と前記負極が接触しないように、前記セパレータで覆われている、第１乃至第４のいずれかの本発明のリチウムイオン二次電池である。 The fifth aspect of the present invention relates to
Either of the strip-shaped side portions of the negative electrode or the strip-shaped side portions of the positive electrode is covered with the separator so that the positive electrode and the negative electrode are not in contact with each other. It is a secondary battery.

第６の本発明は、
前記第１の集電体は、前記帯状の負極の両辺に対する断面形状が湾曲しておらず、かつ、前記第２の集電体は、前記帯状の正極の両辺に対する断面形状が湾曲していない、第１乃至第５のいずれかの本発明のリチウムイオン二次電池である。 The sixth invention relates to
The first current collector is not curved in cross-sectional shape with respect to both sides of the strip-shaped negative electrode, and the second current collector is not curved in cross-sectional shape with respect to both sides of the strip-shaped positive electrode. The lithium ion secondary battery according to any one of the first to fifth aspects of the present invention.

本発明により、寿命特性および信頼性に優れたリチウムイオン二次電池を提供することができる。   According to the present invention, it is possible to provide a lithium ion secondary battery having excellent life characteristics and reliability.

以下に、本発明の実施の形態について、図面を参照しながら説明する。   Embodiments of the present invention will be described below with reference to the drawings.

（実施の形態１）
図１は、本発明の実施の形態１におけるリチウムイオン二次電池の発電要素１の始端Ａおよび終端Ｂを含む方向の断面図である。つまり、従来技術の図５の長手方向の断面、すなわち、従来技術の図６に相当する断面図である。 (Embodiment 1)
FIG. 1 is a cross-sectional view in a direction including the start end A and the end B of the power generation element 1 of the lithium ion secondary battery according to Embodiment 1 of the present invention. That is, it is a sectional view in the longitudinal direction of FIG. 5 of the prior art, that is, a sectional view corresponding to FIG. 6 of the prior art.

図１において、発電要素１は、正極１ａと負極１ｂの間にセパレータ１ｃを介した構造であり、帯状の形状をしている。リチウムイオン二次電池としては、この発電要素１を円筒形または長円筒形（図５に示すような形状）に捲回したもの、または、複数のこの発電要素１を上下に積層したものを用いる。   In FIG. 1, the power generation element 1 has a structure in which a separator 1c is interposed between a positive electrode 1a and a negative electrode 1b, and has a strip shape. As the lithium ion secondary battery, a power generation element 1 wound in a cylindrical shape or a long cylindrical shape (as shown in FIG. 5) or a plurality of power generation elements 1 stacked one above the other is used. .

正極１ａは、例えば、アルミニウム箔等の集電体１０の両面に、コバルト酸リチウム等の活物質と、導電剤、バインダ等の混合物からなる合剤層１１を形成したものである。   In the positive electrode 1a, for example, a mixture layer 11 made of a mixture of an active material such as lithium cobaltate and a conductive agent and a binder is formed on both surfaces of a current collector 10 such as an aluminum foil.

負極１ｂは、例えば、銅箔等の集電体２０の両面に、黒鉛等の活物質と、バインダ等の混合物からなる合剤層２１を形成したものである。   In the negative electrode 1b, for example, a mixture layer 21 made of a mixture of an active material such as graphite and a binder is formed on both surfaces of a current collector 20 such as a copper foil.

なお、正極１ａの集電体１０、合剤層１１は、それぞれ、本発明の第２の集電体、第２の合剤層の一例である。また、負極１ｂの集電体１１、合剤層２１は、それぞれ、本発明の第１の集電体、第１の合剤層の一例である。   The current collector 10 and the mixture layer 11 of the positive electrode 1a are examples of the second current collector and the second mixture layer of the present invention, respectively. The current collector 11 and the mixture layer 21 of the negative electrode 1b are examples of the first current collector and the first mixture layer of the present invention, respectively.

セパレータ１ｃは、多孔体であり、熱による膨張・収縮量の小さい無機酸化物を含有することが好ましい。さらに、他に含有されている有機物等の熱による膨張・収縮によりセパレータ１ｃ全体としての変形量が大きくなることを防止するために、無機酸化物の含有量をセパレータ１ｃの９０重量％以上とすることが望ましい。   The separator 1c is a porous body, and preferably contains an inorganic oxide that has a small amount of expansion / contraction due to heat. Furthermore, in order to prevent the deformation amount of the separator 1c as a whole due to expansion and contraction due to heat of other organic substances contained therein, the content of the inorganic oxide is 90% by weight or more of the separator 1c. It is desirable.

そして、図１に示すように、セパレータ１ｃは負極１ｂの始端部および終端部を被覆しているとともに、負極１ｂの始端部から終端部に至るまで負極合剤層２１表面とセパレータ１ｃが密着している。そして、負極１ｂの始端部から終端部に至るまでの間の負極合剤層２１表面に接している部分のセパレータ１ｃの厚さが均一であることが好ましい。つまり、図１に示すセパレータ１ｃの各部の厚さ、ｔ１、ｔ２、ｔ３、ｔ４が等しいことが好ましい。   As shown in FIG. 1, the separator 1c covers the start and end portions of the negative electrode 1b, and the surface of the negative electrode mixture layer 21 and the separator 1c are in close contact from the start end to the end portion of the negative electrode 1b. ing. And it is preferable that the thickness of the separator 1c of the part which is in contact with the surface of the negative mix layer 21 between the starting end part of the negative electrode 1b and a terminal part is uniform. That is, it is preferable that the thicknesses t1, t2, t3, and t4 of the respective parts of the separator 1c shown in FIG.

なお、負極１ｂの始端部および終端部は、それぞれ、本発明の、一方の端部および他方の端部のいずれかの一例である。   In addition, the start part and termination | terminus part of the negative electrode 1b are examples of either one edge part and the other edge part of this invention, respectively.

次に、本実施の形態１の発電素子１の作製方法について説明する。   Next, a method for manufacturing the power generation element 1 of the first embodiment will be described.

セパレータ１ｃは、例えば、フィラー、バインダ等のセパレータ１ｃを構成する材料を溶媒と混合した塗料を作製し、負極１ｂの表面に、この塗料を塗布、乾燥させることによって形成できる。   The separator 1c can be formed, for example, by preparing a paint in which a material constituting the separator 1c such as a filler and a binder is mixed with a solvent, and applying and drying the paint on the surface of the negative electrode 1b.

このセパレータ１ｃを形成させる塗料の作製には、例えば、プラネタリミキサ、ビーズミル、三本ロールミル、高速回転による遠心力を利用した分散機等を用いることができるが、特に限定されるものではない。   For producing the coating material for forming the separator 1c, for example, a planetary mixer, a bead mill, a three-roll mill, a disperser using a centrifugal force by high-speed rotation, or the like can be used, but is not particularly limited.

また、この塗料を負極１ｂの表面に塗布する方法としては、例えば、スロットダイ、ブレード、フォワードロール、リバースロール、グラビア、スプレー等の塗布方法および装置を用いることができるが、特に限定されるものではない。   Moreover, as a method of applying this paint to the surface of the negative electrode 1b, for example, an application method and apparatus such as slot die, blade, forward roll, reverse roll, gravure, spray and the like can be used, but the method is particularly limited. is not.

また、負極合剤層２１の断面が図１に示すような形状の場合、例えば、スロットダイを用いて、始端部の直前の部分（ｔ１、ｔ２の部分）のみ、塗布膜厚が負極合剤層２１の厚みとセパレータ層１ｃの厚みを加えた厚みとなるように塗布量を変化させることで、図１に示したような厚さが均一なセパレータ１ｃを形成させることができる。   Further, when the cross section of the negative electrode mixture layer 21 has a shape as shown in FIG. 1, for example, using a slot die, the coating thickness of the negative electrode mixture layer is limited to the portion immediately before the start end portion (portions t1 and t2). By changing the coating amount so that the thickness of the layer 21 and the thickness of the separator layer 1c are added, the separator 1c having a uniform thickness as shown in FIG. 1 can be formed.

このような本実施の形態１の構成の発電要素１によれば、セパレータ１ｃが、負極１ｂの始端部および終端部を被覆しているとともに、負極１ｂの始端部から終端部に至るまで負極合剤層２１表面とセパレータ１ｃが密着していることにより、充放電の繰り返しによる金属リチウムの析出がなく、寿命特性および信頼性に優れたリチウムイオン二次電池を実現することができる。   According to the power generating element 1 having the configuration of the first embodiment as described above, the separator 1c covers the starting end portion and the terminal end portion of the negative electrode 1b, and the negative electrode coupling from the starting end portion to the terminal end portion of the negative electrode 1b. Since the surface of the agent layer 21 and the separator 1c are in close contact with each other, there is no precipitation of metallic lithium due to repeated charge / discharge, and a lithium ion secondary battery having excellent life characteristics and reliability can be realized.

さらに、始端部から終端部に至るまでの間の負極合剤層２１表面に接している部分のセパレータ１ｃの厚みを均一にすることで、特に始端部および終端部の近傍において、セパレータ１ｃには露出の危険のある薄肉部や割れやすい厚肉部がなくなり、内部短絡の発生を飛躍的に抑制することができる。   Furthermore, by making the thickness of the separator 1c in the portion in contact with the surface of the negative electrode mixture layer 21 from the start end portion to the end portion uniform, particularly in the vicinity of the start end portion and the end portion, the separator 1c The occurrence of an internal short circuit can be drastically suppressed since there is no thin-walled portion with a risk of exposure or a thick-walled portion that is easily broken.

また、セパレータ１ｃに無機酸化物を含有し、好ましくは、無機酸化物の含有量をセパレータ１ｃの９０重量％以上とすることで、高温時のセパレータ１ｃの収縮が抑制でき、高温時の短絡が生じなくなることから、高温安全性が向上する。   Further, the separator 1c contains an inorganic oxide, and preferably the inorganic oxide content is 90% by weight or more of the separator 1c, so that the shrinkage of the separator 1c at a high temperature can be suppressed, and a short circuit at a high temperature can be prevented. Since it does not occur, high temperature safety is improved.

本実施の形態１において、負極合剤層２１の断面形状は図１の形状に限定されるものではなく、これ以外の形状であってもよい。   In the first embodiment, the cross-sectional shape of the negative electrode mixture layer 21 is not limited to the shape shown in FIG. 1 and may be other shapes.

なお、上記の本実施の形態１の説明では、図１に示すように、負極１ｂの両面をセパレータ１ｃで被覆する構成としたが、セパレータが、負極１ｂではなく正極１ａを被覆する構成であってもよい。   In the above description of the first embodiment, as shown in FIG. 1, the both surfaces of the negative electrode 1b are covered with the separator 1c. However, the separator is not covered with the negative electrode 1b but with the positive electrode 1a. May be.

図２は、正極１ａをセパレータ１ｄで被覆した場合の、本実施の形態１におけるリチウムイオン二次電池の発電要素１の始端Ａおよび終端Ｂを含む方向の断面図である。   FIG. 2 is a cross-sectional view in a direction including the start end A and the end B of the power generation element 1 of the lithium ion secondary battery according to Embodiment 1 when the positive electrode 1a is covered with the separator 1d.

セパレータ１ｄは、図１に示すセパレータ１ｃと同じ材料で形成されている。   Separator 1d is formed of the same material as separator 1c shown in FIG.

図２に示すように、セパレータ１ｄは正極１ａの始端部および終端部を被覆しているとともに、正極１ａの始端部から終端部に至るまで正極合剤層１１表面とセパレータ１ｄが密着している。そして、正極１ａの始端部から終端部に至るまでの間の正極合剤層１１表面に接している部分のセパレータ１ｄの厚さが均一であることが好ましい。   As shown in FIG. 2, the separator 1d covers the start and end portions of the positive electrode 1a, and the surface of the positive electrode mixture layer 11 and the separator 1d are in close contact from the start end to the end portion of the positive electrode 1a. . And it is preferable that the thickness of the separator 1d of the part which is in contact with the surface of the positive mix layer 11 from the start part of the positive electrode 1a to the terminal part is uniform.

また、図２に示す発電要素１の作製方法は、図１で負極１ｂの両面にセパレータ１ｃを形成させたのと同じ方法にて、正極１ａの両面にセパレータ１ｄを形成させて作製する。   The power generation element 1 shown in FIG. 2 is manufactured by forming the separator 1d on both surfaces of the positive electrode 1a in the same manner as the separator 1c is formed on both surfaces of the negative electrode 1b in FIG.

このような図２の構成の発電要素１によれば、セパレータ１ｄが、正極１ａの始端部および終端部を被覆しているとともに、正極１ａの始端部から終端部に至るまで正極合剤層１１表面とセパレータ１ｄが密着していることにより、充放電の繰り返しによる金属リチウムの析出がなく、図１の場合と同様に、寿命特性および信頼性に優れたリチウムイオン二次電池を実現することができる。   According to the power generation element 1 having the configuration shown in FIG. 2, the separator 1 d covers the start end and the end of the positive electrode 1 a, and the positive electrode mixture layer 11 extends from the start end to the end of the positive electrode 1 a. Since the surface and the separator 1d are in close contact with each other, there is no precipitation of metallic lithium due to repeated charge and discharge, and a lithium ion secondary battery having excellent life characteristics and reliability can be realized as in the case of FIG. it can.

（実施の形態２）
図３および図４は、本発明の実施の形態２のリチウムイオン二次電池の発電要素１の側端を含む方向、つまり図１とは垂直な方向の断面図である。つまり、従来技術の図５の始端Ａおよび終端Ｂを含まない、短い側に相当する断面図である。なお、始端Ａおよび終端Ｂを含む方向の断面図は、実施の形態１と同様で、図１の通りである。 (Embodiment 2)
3 and 4 are cross-sectional views in the direction including the side end of the power generation element 1 of the lithium ion secondary battery according to Embodiment 2 of the present invention, that is, in the direction perpendicular to FIG. That is, FIG. 6 is a cross-sectional view corresponding to the short side that does not include the start end A and the end point B of FIG. A cross-sectional view in the direction including the start end A and the end end B is the same as that in the first embodiment and is as shown in FIG.

図３において、発電要素１は、正極１ａと両面をセパレータ１ｃで被覆された負極１ｂが重なった構造であり、帯状の形状をしている。リチウムイオン二次電池としては、この発電要素１を円筒形または長円筒形（図５に示すような形状）に捲回したもの、または、この発電要素１を上下に積層したものを用いる。   In FIG. 3, the power generation element 1 has a structure in which a positive electrode 1a and a negative electrode 1b whose both surfaces are coated with a separator 1c overlap each other, and has a strip shape. As the lithium ion secondary battery, a power generation element 1 wound in a cylindrical or long cylindrical shape (as shown in FIG. 5) or a structure in which the power generation element 1 is stacked vertically is used.

正極１ａは、例えば、アルミニウム箔等の集電体１０の両面に、コバルト酸リチウム等の活物質と、導電剤、バインダ等の混合物からなる合剤層１１を形成したものである。   In the positive electrode 1a, for example, a mixture layer 11 made of a mixture of an active material such as lithium cobaltate and a conductive agent and a binder is formed on both surfaces of a current collector 10 such as an aluminum foil.

負極１ｂは、例えば、銅箔等の集電体２０の両面に、黒鉛等の活物質と、バインダ等の混合物からなる合剤層２１を形成したものである。   In the negative electrode 1b, for example, a mixture layer 21 made of a mixture of an active material such as graphite and a binder is formed on both surfaces of a current collector 20 such as a copper foil.

そして、セパレータ１ｃは、多孔体であり、図３に示すように、負極１ｂの側端部を被覆している。   And the separator 1c is a porous body, and has coat | covered the side edge part of the negative electrode 1b, as shown in FIG.

図４は、図３とは異なる、発電要素１の構成例である。   FIG. 4 is a configuration example of the power generation element 1 different from FIG.

図４において、発電要素１は、正極１ａと負極１ｂの間にセパレータ１ｃを介した構造であり、帯状の形状をしている。リチウムイオン二次電池としては、この発電要素１を円筒形または長円筒形（図５に示すような形状）に捲回したもの、または、この発電要素１を上下に積層したものを用いる。   In FIG. 4, the power generation element 1 has a structure in which a separator 1c is interposed between a positive electrode 1a and a negative electrode 1b, and has a strip shape. As the lithium ion secondary battery, a power generation element 1 wound in a cylindrical or long cylindrical shape (as shown in FIG. 5) or a structure in which the power generation element 1 is stacked vertically is used.

正極１ａは、例えば、アルミニウム箔等の集電体１０の両面に、コバルト酸リチウム等の活物質と、導電剤、バインダ等の混合物からなる合剤層１１を形成したものである。   In the positive electrode 1a, for example, a mixture layer 11 made of a mixture of an active material such as lithium cobaltate and a conductive agent and a binder is formed on both surfaces of a current collector 10 such as an aluminum foil.

負極１ｂは、例えば、銅箔等の集電体２０の両面に、黒鉛等の活物質と、バインダ等の混合物からなる合剤層２１を形成したものである。   In the negative electrode 1b, for example, a mixture layer 21 made of a mixture of an active material such as graphite and a binder is formed on both surfaces of a current collector 20 such as a copper foil.

そして、セパレータ１ｃは、多孔体であり、図４に示すように、正極１ａと負極１ｂの間に配置されている。   And the separator 1c is a porous body, and as shown in FIG. 4, it is arrange | positioned between the positive electrode 1a and the negative electrode 1b.

なお、正極１ａの集電体１０、合剤層１１は、それぞれ、本発明の第２の集電体、第２の合剤層の一例である。また、負極１ｂの集電体１１、合剤層２１は、それぞれ、本発明の第１の集電体、第１の合剤層の一例である。   The current collector 10 and the mixture layer 11 of the positive electrode 1a are examples of the second current collector and the second mixture layer of the present invention, respectively. The current collector 11 and the mixture layer 21 of the negative electrode 1b are examples of the first current collector and the first mixture layer of the present invention, respectively.

なお、本発明の負極の帯状の両辺に対する断面形状とは、本実施の形態２で示した図３、図４で示した断面の形状のことである。   In addition, the cross-sectional shape with respect to both strip-like sides of the negative electrode of the present invention is the cross-sectional shape shown in FIGS. 3 and 4 shown in the second embodiment.

一般に、リチウムイオン二次電池の発電要素１は、広幅で作製された正極および負極を電池の高さの寸法に合わせてスリットして用いられる。しかし、このスリットの方法および条件によって、集電体の側端は隣接するいずれかの合剤層側に反ってしまい、発電要素１の側端を含む方向の断面は、例えば図７に示すような形状になってしまう。このため、側端部において、正極１ａと負極１ｂの短絡が生じやすくなる。なお、図７において、図１と同じ構成要素については同じ符号を用いる。   In general, the power generation element 1 of a lithium ion secondary battery is used by slitting a positive electrode and a negative electrode manufactured in a wide width in accordance with the height of the battery. However, depending on the method and conditions of the slit, the side end of the current collector warps to any adjacent mixture layer side, and the cross section in the direction including the side end of the power generation element 1 is, for example, as shown in FIG. It will become the shape. For this reason, it becomes easy to produce the short circuit of the positive electrode 1a and the negative electrode 1b in a side edge part. In FIG. 7, the same components as those in FIG.

本実施の形態２の発電要素１では、図３に示すように負極１ｂの側端部をセパレータ１ｃで被覆する、あるいは、適切なスリット方法および条件によって図４に示すような断面形状として、集電体２０が隣接するいずれかの合剤層２１側に反らないようにしている。なお、負極１ｂの側端部は、本発明の、負極の帯状の両辺部の一例である。   In the power generating element 1 of the second embodiment, the side end of the negative electrode 1b is covered with the separator 1c as shown in FIG. 3, or the cross-sectional shape as shown in FIG. 4 is collected by an appropriate slitting method and conditions. The electric body 20 is made not to warp to the adjacent mixture layer 21 side. In addition, the side edge part of the negative electrode 1b is an example of the strip | belt-shaped both sides of a negative electrode of this invention.

例えば、発電要素１を図４に示すような集電体２０が反っていない断面形状とするためには、適切なスリットの刃の形状を選定する、または、図７のような断面形状になった負極１ｂを曲げ加工により反りを無くすといった方法がある。発電要素１を図３または図４に示すような、湾曲していない断面形状とするための方法については、特に限定されるものではない。   For example, in order to make the power generating element 1 have a cross-sectional shape in which the current collector 20 is not warped as shown in FIG. 4, an appropriate slit blade shape is selected, or a cross-sectional shape as shown in FIG. There is a method of eliminating warping by bending the negative electrode 1b. The method for making the power generating element 1 into a non-curved cross-sectional shape as shown in FIG. 3 or FIG. 4 is not particularly limited.

このような本実施の形態２の発電要素１の構成によれば、寿命特性および信頼性に優れたリチウムイオン二次電池を実現するとともに、側端部において正極１ａと負極１ｂが接触することがなく、側端部における内部短絡も生じなくなる。   According to such a configuration of the power generation element 1 of the second embodiment, a lithium ion secondary battery having excellent life characteristics and reliability can be realized, and the positive electrode 1a and the negative electrode 1b can be in contact with each other at the side end. No internal short circuit occurs at the side end.

なお、図３に示した本実施の形態２の発電要素１の構成は、負極１ｂの側端部をセパレータ１ｃで被覆する構成としたが、セパレータが、負極１ｂではなく正極１ａの側端部を被覆する構成であってもよい。   In addition, although the structure of the electric power generation element 1 of this Embodiment 2 shown in FIG. 3 was set as the structure which coat | covers the side edge part of the negative electrode 1b with the separator 1c, a separator is not the negative electrode 1b but the side edge part of the positive electrode 1a. The structure which coat | covers may be sufficient.

この場合にも、図３、図４で説明した方法により、正極１ａの断面形状が湾曲しないようにすることで、寿命特性および信頼性に優れたリチウムイオン二次電池を実現するとともに、側端部において正極１ａと負極１ｂが接触することがなく、側端部における内部短絡も生じさせないようにできる。   Also in this case, by making the cross-sectional shape of the positive electrode 1a not curved by the method described with reference to FIGS. 3 and 4, a lithium ion secondary battery having excellent life characteristics and reliability can be realized. This prevents the positive electrode 1a and the negative electrode 1b from coming into contact with each other and prevents an internal short circuit from occurring at the side end.

本発明のリチウムイオン二次電池は、優れた寿命特性および信頼性を有し、固体電解質リチウム二次電池、ニッケル水素電池等のエネルギ貯蔵素子の用途にも適用できる。   The lithium ion secondary battery of the present invention has excellent life characteristics and reliability, and can be applied to uses of energy storage elements such as solid electrolyte lithium secondary batteries and nickel metal hydride batteries.

本発明の実施の形態１におけるリチウムイオン二次電池の発電要素の始端および終端を含む方向の断面図Sectional drawing of the direction containing the start end and termination | terminus of the electric power generation element of the lithium ion secondary battery in Embodiment 1 of this invention 本発明の実施の形態１におけるリチウムイオン二次電池の発電要素の始端および終端を含む方向の断面図Sectional drawing of the direction containing the start end and termination | terminus of the electric power generation element of the lithium ion secondary battery in Embodiment 1 of this invention 本発明の実施の形態２におけるリチウムイオン二次電池の発電要素の側端を含む方向の断面図Sectional drawing of the direction containing the side end of the electric power generation element of the lithium ion secondary battery in Embodiment 2 of this invention 本発明の実施の形態２におけるリチウムイオン二次電池の発電要素の側端を含む方向の断面図Sectional drawing of the direction containing the side end of the electric power generation element of the lithium ion secondary battery in Embodiment 2 of this invention 従来のリチウムイオン二次電池の発電要素の斜視図A perspective view of a power generation element of a conventional lithium ion secondary battery 従来のリチウムイオン二次電池の発電要素の始端および終端を含む方向の断面図Sectional drawing of the direction including the start end and termination | terminus of the electric power generation element of the conventional lithium ion secondary battery 従来のリチウムイオン二次電池の発電要素の側端を含む方向の断面図Sectional drawing of the direction including the side end of the power generation element of the conventional lithium ion secondary battery

符号の説明Explanation of symbols

１ 発電要素
１ａ 正極
１ｂ 負極
１ｃ、１ｄ セパレータ
１０、２０ 集電体
１１、２１ 合材層
Ａ 始端
Ｂ 終端 DESCRIPTION OF SYMBOLS 1 Electric power generation element 1a Positive electrode 1b Negative electrode 1c, 1d Separator 10, 20 Current collector 11, 21 Compound material layer A Start end B End

Claims (6)

第１の集電体の両面に第１の合材層が形成された帯状の負極と、第２の集電体の両面に第２の合材層が形成された帯状の正極と、前記負極の両面または前記正極の両面に前記正極と前記負極が接触しないように配置される帯状のセパレータとで発電要素を形成しており、一の前記発電要素が捲回された構成、または、複数の前記発電要素が積層された構成を有するリチウムイオン二次電池において、
前記第１の集電体の両面の２つの前記第１の合材層または前記第２の集電体の両面の２つの前記第２の合材層は、その一方の端部から他方の端部に至るまで前記セパレータで覆われており、さらに、いずれも、前記一方の端部から前記他方の端部に至るまで前記セパレータと接着している、リチウムイオン二次電池。 A strip-shaped negative electrode in which a first composite material layer is formed on both surfaces of a first current collector, a strip-shaped positive electrode in which a second composite material layer is formed on both surfaces of a second current collector, and the negative electrode A power generation element is formed by a strip-shaped separator disposed so that the positive electrode and the negative electrode do not contact each other on both surfaces of the positive electrode or the positive electrode, and a configuration in which one power generation element is wound, or a plurality of In a lithium ion secondary battery having a configuration in which the power generation elements are stacked,
The two first composite layers on both sides of the first current collector or the two second composite layers on both sides of the second current collector are arranged from one end to the other end. The lithium ion secondary battery is covered with the separator until it reaches the portion, and is further bonded to the separator from the one end to the other end. 前記第１の合材層または前記第２の合材層と接着している部分の前記セパレータの厚さは実質上均一である、請求項１に記載のリチウムイオン二次電池。   2. The lithium ion secondary battery according to claim 1, wherein a thickness of the separator in a portion bonded to the first composite material layer or the second composite material layer is substantially uniform. 前記セパレータは無機酸化物を含有している、請求項１または２に記載のリチウムイオン二次電池。   The lithium ion secondary battery according to claim 1 or 2, wherein the separator contains an inorganic oxide. 前記セパレータの前記無機酸化物の含有量は９０重量％以上である、請求項３に記載のリチウムイオン二次電池。   The lithium ion secondary battery according to claim 3, wherein the content of the inorganic oxide in the separator is 90% by weight or more. 前記負極の帯状の両辺部または前記正極の帯状の両辺部は、前記正極と前記負極が接触しないように、前記セパレータで覆われている、請求項１乃至４のいずれかに記載のリチウムイオン二次電池。   The both sides of the strip of the negative electrode or both sides of the strip of the positive electrode are covered with the separator so that the positive electrode and the negative electrode are not in contact with each other. Next battery. 前記第１の集電体は、前記帯状の負極の両辺に対する断面形状が湾曲しておらず、かつ、前記第２の集電体は、前記帯状の正極の両辺に対する断面形状が湾曲していない、請求項１乃至５のいずれかに記載のリチウムイオン二次電池。
The first current collector is not curved in cross-sectional shape with respect to both sides of the strip-shaped negative electrode, and the second current collector is not curved in cross-sectional shape with respect to both sides of the strip-shaped positive electrode. The lithium ion secondary battery according to any one of claims 1 to 5.
JP2003414244A 2003-12-12 2003-12-12 Lithium ion secondary cell Pending JP2005174779A (en)

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JPWO2017110318A1 (en) * 2015-12-25 2018-10-11 株式会社豊田自動織機 Power storage device and method for manufacturing electrode unit
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