JP2010080390A - Battery - Google Patents

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JP2010080390A
JP2010080390A JP2008250178A JP2008250178A JP2010080390A JP 2010080390 A JP2010080390 A JP 2010080390A JP 2008250178 A JP2008250178 A JP 2008250178A JP 2008250178 A JP2008250178 A JP 2008250178A JP 2010080390 A JP2010080390 A JP 2010080390A
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battery
positive electrode
active material
separator
negative electrode
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Yasunori Baba
泰憲 馬場
Naoki Imachi
直希 井町
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Sanyo Electric Co Ltd
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Sanyo Electric 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 provide a battery in which contact of a positive electrode and a negative electrode active material layers is suppressed and function of the battery is stopped by promptly lowering the potential of the positive electrode and raising the potential of the negative electrode, when the battery is exposed to an abnormal state, and thereby reliability of the battery is remarkably improved. <P>SOLUTION: The battery has a structure in which a wound electrode body 5 wound around in spiral form is contained in a metallic outer package can, and the metallic outer package can and a negative electrode plate are electrically connected. A positive electrode plate is arranged through a separator 3 in the outermost periphery of the wound electrode body, and a current collector exposed part 1c which projects more than a winding terminal part 3a of the separator 3 and in which the positive electrode active material layer 1b does not exist is installed on the winding terminal side in the outermost periphery of the positive electrode plate, and the battery outside face of this current collector exposed part 1c is covered with a low-density polyethylene film 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

本発明は電池に関し、特に、リチウムイオン電池或いはポリマー電池等の非水電解質二次電池に関するものである。   The present invention relates to a battery, and more particularly to a non-aqueous electrolyte secondary battery such as a lithium ion battery or a polymer battery.

近年、携帯電話、ノートパソコン、ＰＤＡ等の移動情報端末の小型・軽量化が急速に進展しており、その駆動電源としての電池にはさらなる高容量化が要求されている。充放電に伴い、リチウムイオンが正、負極間を移動することにより充放電を行う非水電解質二次電池は、高いエネルギー密度を有し、高容量であるので、上記のような移動情報端末の駆動電源として広く利用されている。   In recent years, mobile information terminals such as mobile phones, notebook personal computers, and PDAs have been rapidly reduced in size and weight, and batteries as drive power sources are required to have higher capacities. A non-aqueous electrolyte secondary battery that performs charge / discharge by moving lithium ions between the positive and negative electrodes along with charge / discharge has a high energy density and a high capacity. Widely used as a drive power source.

ここで、上記移動情報端末は、動画再生機能、ゲーム機能といった機能の充実に伴って、更に消費電力が高まる傾向にあり、その駆動電源であるリチウムイオン電池には長時間再生や出力改善等を目的として、更なる高容量化や高性能化が強く望まれるところである。加えて、非水電解質二次電池は上記用途のみならず、電動工具やアシスト自転車、更にはＨＥＶ等の用途への展開も期待されおり、このような新用途に対応するためにも、更なる高容量化や高性能化を図ると共に、高信頼性化が強く望まれるところである。   Here, the mobile information terminal has a tendency to further increase the power consumption with enhancement of functions such as a video playback function and a game function. As a purpose, further increase in capacity and performance are strongly desired. In addition, non-aqueous electrolyte secondary batteries are expected to be used not only for the above applications, but also for electric tools, assist bicycles, and HEVs. In addition to increasing capacity and performance, high reliability is strongly desired.

ここで、上記非水電解質二次電池のセパレータとして広く用いられているポリオレフィン系の徴多孔膜は、電池温度上昇時に、延伸によって作製された空孔が閉塞されることで発動するシャットダウン機能により、電池信頼性向上のための大きな役割を担っている。しかしながら、電池温度が大きく上昇し、ポリオレフィンの融点を越えると、セパレータが収縮し、正負極活物質層同士が接触することで、短絡を招いてしまう。このような短絡時には、短絡部に大電流が流れ局所的に温度上昇するが、上記の如く正負極活物質層同士が接触している部位で短絡した場合には、正負極活物質および電解液の急激な熱分解反応を引き起こすという問題がある。   Here, the polyolefin-based porous membrane widely used as the separator of the non-aqueous electrolyte secondary battery has a shutdown function that is activated by closing the pores created by stretching when the battery temperature rises. It plays a major role in improving battery reliability. However, when the battery temperature rises greatly and exceeds the melting point of polyolefin, the separator contracts and the positive and negative electrode active material layers come into contact with each other, thereby causing a short circuit. When such a short circuit occurs, a large current flows through the short circuit part and the temperature rises locally. However, when a short circuit occurs at the part where the positive and negative electrode active material layers are in contact with each other as described above, the positive and negative electrode active materials and the electrolyte solution There is a problem of causing a rapid thermal decomposition reaction.

このようなことを考慮して、以下に示す技術が提案されている。
（１）ポリオレフィン系の徴多孔膜と無機微粒子や耐熱性樹脂とを複合することで、セパレータの耐熱性を向上させ（セパレータの収縮を抑制して）、正負極活物質同士の短絡を抑制するような技術。 In consideration of the above, the following techniques have been proposed.
(1) By combining a polyolefin-based porous film, inorganic fine particles, and a heat-resistant resin, the heat resistance of the separator is improved (suppressing the shrinkage of the separator) and the short circuit between the positive and negative electrode active materials is suppressed. Like technology.

（２）非水電解質二次電池のセパレータとして多く用いられているポリオレフィン系の徴多孔膜は、電池温度が上昇した場合、１３０〜１４０℃の温度でシャットダウンが機能するが、このシャットダウンより早期に機能する安全機構を電池内に組み込むことができれば、電池の信頼性をより向上させることが出来る。このような観点から、セパレータよりも融点の低い高分子粒子層をセパレータ表面に設け、セパレータのシャットダウンが生じる前に溶融して、セパレータの空孔を閉塞させる技術（下記特許文献１参照）。 (2) Polyolefin-based porous membranes that are often used as separators for non-aqueous electrolyte secondary batteries, when the battery temperature rises, the shutdown functions at a temperature of 130 to 140 ° C., but earlier than this shutdown If a functioning safety mechanism can be incorporated into the battery, the reliability of the battery can be further improved. From such a viewpoint, a technique in which a polymer particle layer having a melting point lower than that of the separator is provided on the surface of the separator and melted before the separator is shut down to block the pores of the separator (see Patent Document 1 below).

（３）負極板と対向する電池ケースの内面に所定の抵抗率の導電層を備えることにより、高温環境下に電池をおいた場合、セパレータの収縮により、負極板と正極板とが導電層を介して接触する技術（下記特許文献２参照）。 (3) By providing a conductive layer having a predetermined resistivity on the inner surface of the battery case facing the negative electrode plate, when the battery is placed in a high temperature environment, the negative electrode plate and the positive electrode plate become conductive layers due to the shrinkage of the separator. (See Patent Document 2 below).

特開２００８−４１５０４号公報JP 2008-41504 A 特開２００５−２８５５５４号公報JP 2005-285554 A

・上記（１）や（２）に示した技術の課題
上記非水電解質二次電池で用いられている正負両活物質では、充電状態（即ち、正極の電位が高い状態で、負極の電位が低い状態）では、熱的に不安定である。したがって、何らかの要因で電池温度が上昇していくと、正負両活物質の分解や電解液との急激な反応が生じて発熱するため、電池内部は非常に不安定な状態となってしまう。
上記背景技術で示した技術（セパレータの耐熱性を向上させて収縮を抑制する技術や、セパレータのシャットダウン温度を低下させる技術）を用いても、電池温度上昇時に正負両活物質が充電状態に維持されることには変わりないため、正負両活物質の分解や電解液との急激な発熱反応が生じる。この結果、電池の信頼性を充分確保することができない。 -Problems of the technology shown in (1) and (2) In the positive and negative active materials used in the non-aqueous electrolyte secondary battery, the charged state (that is, the positive electrode has a high potential and the negative electrode has a high potential). In the low state, it is thermally unstable. Therefore, when the battery temperature rises for some reason, the inside of the battery becomes very unstable because the positive and negative active materials are decomposed and a rapid reaction with the electrolytic solution occurs to generate heat.
Both positive and negative active materials remain charged when the battery temperature rises, even when using the technologies shown in the above background art (technology that improves the heat resistance of the separator and suppresses shrinkage, and technology that reduces the shutdown temperature of the separator) Therefore, both positive and negative active materials are decomposed and a rapid exothermic reaction with the electrolytic solution occurs. As a result, sufficient battery reliability cannot be ensured.

・上記（３）に示した技術の課題
セパレータとして熱収縮性のものを用いているが、このような構成では、セパレータが熱収縮するまで（即ち、電池が高温となるまで）は正極と負極とが短絡しない。したがって、電池温度が高くなるまで正負両活物質が充電状態に維持されるため、やはり正負両活物質の分解等が生じて、電池の信頼性が低下する。また、負極板と正極板とが導電層を介して接触する際、負極集電体と導電層とが接触するのみならず、負極活物質層と導電層とが接触する。このように、負極活物質が存在する部位にて直接短絡すると、当該部位で急激に温度上昇が生じて活物質の分解等が助長されるため、電池の信頼性が一層低下する。 ・ Problems of the technology shown in (3) The heat-shrinkable separator is used. In such a configuration, the positive electrode and the negative electrode are used until the separator heat-shrinks (that is, until the battery reaches a high temperature). And do not short circuit. Therefore, since both the positive and negative active materials are maintained in the charged state until the battery temperature is increased, the positive and negative active materials are decomposed and the reliability of the battery is lowered. Further, when the negative electrode plate and the positive electrode plate are in contact via the conductive layer, not only the negative electrode current collector and the conductive layer are in contact but also the negative electrode active material layer and the conductive layer are in contact. As described above, when a short circuit occurs directly at the site where the negative electrode active material exists, the temperature rapidly increases at the site and the decomposition of the active material is promoted, so that the reliability of the battery further decreases.

したがって、本発明は、電池が異常状態に曝された場合に、正負極活物質層同士が接触するのを抑制すると共に、早期に正極の電位を下げ且つ負極の電位を上げることで電池の機能を停止させ、これによって、信頼性を格段に向上させることができる電池の提供を目的としている。   Therefore, the present invention suppresses the contact between the positive and negative electrode active material layers when the battery is exposed to an abnormal state, and lowers the positive electrode potential and raises the negative electrode potential at an early stage. This is intended to provide a battery that can significantly improve reliability.

上記目的を達成するために本発明は、正極集電体の表面に正極活物質層が形成された正極板と、負極集電体の表面に負極活物質層が形成された負極板とが、セパレータを介して渦巻状に巻回された巻取電極体を有し、この巻取電極体が金属外装缶内に収納されると共に、この金属外装缶と上記両極板のうち一方の極板とが電気的に接続された構造の電池において、上記巻取電極体の最外周部には、上記セパレータを介して上記金属外装缶とは異なる極性の極板が配置されると共に、当該極板の最外周部における巻回終端側には、上記セパレータの巻回終端部よりも突出し、上記活物質層が存在しない集電体露出部が設けられ、しかも、この集電体露出部の電池外側面が、上記セパレータより低融点で且つ製造段階での乾燥工程における乾燥温度よりも高融点の絶縁性フィルムで覆われていることを特徴とする。   To achieve the above object, the present invention provides a positive electrode plate having a positive electrode active material layer formed on the surface of a positive electrode current collector and a negative electrode plate having a negative electrode current collector formed with a negative electrode active material layer on the surface thereof. A winding electrode body wound in a spiral shape via a separator, and the winding electrode body is housed in a metal outer can, and the metal outer can and one of the two electrode plates; In the battery having a structure in which is electrically connected, an electrode plate having a polarity different from that of the metal outer can is disposed on the outermost peripheral portion of the winding electrode body via the separator. On the winding end side in the outermost peripheral portion, a current collector exposed portion that protrudes from the winding end portion of the separator and does not have the active material layer is provided, and the battery outer surface of the current collector exposed portion Has a lower melting point than the separator and the drying temperature in the drying process in the production stage. Characterized in that it is covered with an insulating film of high melting point than.

上記構成の如く、セパレータより低融点の絶縁性フィルムで覆われた集電体露出部が、金属外装缶とは異なる極性の極板における最外周部に設けられていれば、何らかの要因で電池温度が上昇した場合、セパレータの融点以下で絶縁性フィルムが溶融、収縮する。したがって、セパレータが溶融して正負両活物質層が直接接触して短絡するより前に、金属外装缶とは異なる極性の極板の集電体露出部と金属外装缶とが接触して短絡し、これにより、正極の電位が下がり且つ負極の電位が上がるので、電池が放電状態となる。このように、セパレータの融点以下で短絡が生じ、異常状態の早期に正負両活物質が安定化すれば、電池温度が更に上昇した場合であっても、正負両活物質の熱分解や電解液との急激な発熱反応が生じるのを抑制することができる。また、正負両活物質層が直接接触するような短絡を伴わないため、正負両活物質の局所的な温度上昇なしに電池を安定化させることができる。これらのことから、電池温度上昇時においても、信頼性の高い電池を得ることができる。   If the current collector exposed portion covered with an insulating film having a melting point lower than that of the separator is provided on the outermost peripheral portion of the electrode plate having a polarity different from that of the metal outer can as in the above configuration, the battery temperature is caused by some factor. When rises, the insulating film melts and shrinks below the melting point of the separator. Therefore, before the separator melts and the positive and negative active material layers directly contact and short-circuit, the current collector exposed portion of the electrode plate having a polarity different from that of the metal outer can and the metal outer can contact and short-circuit. As a result, the potential of the positive electrode is lowered and the potential of the negative electrode is raised, so that the battery is discharged. Thus, if a short circuit occurs below the melting point of the separator and the positive and negative active materials are stabilized at an early stage of an abnormal state, even if the battery temperature further increases, the thermal decomposition of the positive and negative active materials and the electrolyte solution The rapid exothermic reaction can be suppressed. In addition, since there is no short circuit in which both the positive and negative active material layers are in direct contact, the battery can be stabilized without a local temperature increase of both the positive and negative active materials. For these reasons, a highly reliable battery can be obtained even when the battery temperature rises.

尚、金属外装缶とは異なる極性の極板の集電体露出部を覆う絶縁性フィルムは、通常の使用状態では溶融しないので、通常状態では、金属外装缶と上記集電体露出部との絶縁性は保持されることになる。   The insulating film covering the current collector exposed portion of the electrode plate having a polarity different from that of the metal outer can is not melted in a normal use state. Therefore, in a normal state, the metal outer can and the current collector exposed portion The insulating property is maintained.

ここで、特開平１０−２６１４２７号公報には、正極端子を兼ねた電池ケースと、最外周に配された負極と電気的に接続された金属箔膜と、電池ケースと金属箔膜とが電気的に非接触状態を保持する絶縁性の保持手段とを備えてなる短絡手段が設けられている旨記載されている。しかしながら、この発明は、過大な応力や加速度を加えて電池を変形させた場合の安全機構であり、本発明のように高温状態での安全性を確保することはできない。なぜなら、上記絶縁性の保持手段としてはセパレータ、紙、或いはセラミックが例示されているに過ぎず、このような物質で保持手段が構成されている場合には、セパレータ等の溶融温度に達するまでは短絡しない。この結果、高温状態となった際、セパレータが溶融する以前に金属同士を短絡させるという本発明の作用効果を発揮できないからである。   Here, in Japanese Patent Laid-Open No. 10-261427, a battery case that also serves as a positive electrode terminal, a metal foil film that is electrically connected to a negative electrode disposed on the outermost periphery, and the battery case and the metal foil film are electrically connected. In addition, it is described that a short-circuit means including an insulating holding means for maintaining a non-contact state is provided. However, the present invention is a safety mechanism when the battery is deformed by applying excessive stress or acceleration, and it is not possible to ensure safety at high temperatures as in the present invention. This is because separators, papers, or ceramics are merely exemplified as the insulating holding means, and when the holding means is constituted by such a substance, until the melting temperature of the separators or the like is reached. Do not short circuit. As a result, when it becomes a high temperature state, it is because the effect of this invention of short-circuiting metals cannot be exhibited before a separator fuse | melts.

上記金属外装缶とは異なる極性の極板において、活物質層の巻回終端側の端部は、上記セパレータで覆われていることが望ましい。
活物質層の巻回終端側の端部とセパレータの端部とが揃っている場合には、絶縁性フィルムが溶融、収縮した場合に、電池の振動や電池の変形等が生じると、金属外装缶と異なる極性の活物質と金属外装缶とが直接接するおそれがある。しかしながら、上記構成の如く、活物質層の巻回終端側の端部がセパレータで覆われていれば、電池の振動や電池の変形等が生じた場合であっても、金属外装缶と異なる極性の活物質と金属外装缶とが直接接するのを抑制できるので、電池の信頼性が一層向上する。 In the electrode plate having a polarity different from that of the metal outer can, it is desirable that the end of the active material layer on the winding end side is covered with the separator.
When the end of the active material layer on the winding end side and the end of the separator are aligned, when the insulating film melts and contracts, if the battery vibrates or deforms, the metal exterior There is a possibility that an active material having a polarity different from that of the can and the metal outer can come into direct contact. However, as in the above configuration, if the end of the active material layer on the winding end side is covered with a separator, even if battery vibration or battery deformation occurs, the polarity is different from that of the metal outer can. Since the direct contact between the active material and the metal outer can can be suppressed, the reliability of the battery is further improved.

上記正極活物質層の活物質及び上記負極活物質層の活物質として、リチウムイオンを挿入脱離できうるものを用いることが望ましい。
このようなリチウムイオン二次電池では、正負両活物質の分解や電解液との急激な発熱反応が顕著であるので、本発明の作用効果が一層発揮される。 It is desirable to use an active material for the positive electrode active material layer and an active material for the negative electrode active material layer that can insert and desorb lithium ions.
In such a lithium ion secondary battery, since the decomposition of both the positive and negative active materials and the rapid exothermic reaction with the electrolytic solution are remarkable, the effects of the present invention are further exhibited.

本発明によれば、電池が異常状態に曝された場合に、正負両活物質同士が接触するのを抑制すると共に、早期に電池を放電状態とすることによって、電池の信頼性を格段に向上させることができるという優れた効果を奏する。   According to the present invention, when the battery is exposed to an abnormal state, the positive and negative active materials are prevented from coming into contact with each other, and the battery is brought into a discharged state at an early stage, thereby significantly improving the reliability of the battery. There is an excellent effect that can be made.

以下、本発明の一例に係る円筒型リチウムイオン二次電池を、以下に説明する。なお、本発明における電池は、下記の形態に示したものに限定されず、その要旨を変更しない範囲において適宜変更して実施できるものである。   Hereinafter, a cylindrical lithium ion secondary battery according to an example of the present invention will be described. In addition, the battery in this invention is not limited to what was shown to the following form, In the range which does not change the summary, it can change suitably and can implement.

円筒型リチウムイオン二次電池は、図１に示すように、上部に開口部を有する有底円筒状の金属外装缶４と、正極板１と負極板２とをポリエチレン製多孔質膜から成るセパレータ３（融点：１３４℃、厚さ：１８μｍ）を介して対向させ渦巻き状に巻回させてなる巻取電極体５と、この巻取電極体５内に含浸された非水電解液と、上記金属外装缶１の開口部を封口する封口蓋６等から構成されている。上記封口蓋６が正極端子、上記金属外装缶１が負極端子となっており、巻取電極体５の上面側に取り付けられている正極集電タブ（図示せず）が封口蓋６と、下面側に取り付けられている負極集電タブ（図示せず）が金属外装缶１と、それぞれ接続され、これによって二次電池としての充電及び放電が可能な構造となっている。上記巻取電極体５の上面及び下面は、上記巻取電極体５と金属外装缶１等とを絶縁するための上部絶縁板９及び下部絶縁板１０で覆われている。また、上記封口蓋６は、絶縁パッキング１１を介して金属外装缶１の開口部にかしめ固定されている。   As shown in FIG. 1, a cylindrical lithium ion secondary battery includes a bottomed cylindrical metal outer can 4 having an opening on the top, a positive electrode plate 1 and a negative electrode plate 2 made of a polyethylene porous membrane. 3 (melting point: 134 ° C., thickness: 18 μm) facing each other through a spirally wound electrode body 5, a non-aqueous electrolyte impregnated in the wound electrode body 5, and the above It is comprised from the sealing lid 6 etc. which seal the opening part of the metal exterior can 1. FIG. The sealing lid 6 is a positive electrode terminal, the metal outer can 1 is a negative electrode terminal, and a positive electrode current collecting tab (not shown) attached to the upper surface side of the winding electrode body 5 is connected to the sealing lid 6 and the lower surface. The negative electrode current collection tab (not shown) attached to the side is each connected with the metal exterior can 1, and it has the structure which can be charged and discharged as a secondary battery by this. The upper and lower surfaces of the winding electrode body 5 are covered with an upper insulating plate 9 and a lower insulating plate 10 for insulating the winding electrode body 5 from the metal outer can 1 and the like. The sealing lid 6 is fixed by caulking to the opening of the metal outer can 1 through an insulating packing 11.

ここで、上記巻取電極体５の最外周部には、セパレータ３を介して正極板１（金属外装缶４とは異なる極性の極板）が配置されており、また、図３に示すように、上記正極板１は、アルミニウム箔から成る正極集電体１ａ（厚さ：１５μｍ）の両面に正極活物質層１ｂ（片面の厚さ：７０μｍ）が形成されるような構造となっている。上記正極板１における巻回終端側には、図２及び図３に示すように、上記正極活物質層１ｂが存在しない正極集電体露出部１ｃが設けられており、また、正極活物質層１ｂの巻回終端側の端部１ｅは、セパレータ３で覆われている。更に、上記正極集電体露出部１ｃの電池外側面１ｄ及びセパレータ３の一部には、セパレータ３より低融点の低密度ポリエチレンフィルム（ＬＤＰＥ、融点：１２０℃）２０が貼り付けられている。尚、上記負極板２は、銅箔から成る負極集電体２ａ（厚さ：８μｍ）の両面に負極活物質層２ｂ（片面の厚さ：６８μｍ）が形成されるような構造となっている。   Here, a positive electrode plate 1 (an electrode plate having a polarity different from that of the metal outer can 4) is disposed on the outermost peripheral portion of the winding electrode body 5 via a separator 3, and as shown in FIG. 3. The positive electrode plate 1 has a structure in which a positive electrode active material layer 1b (thickness on one side: 70 μm) is formed on both surfaces of a positive electrode current collector 1a (thickness: 15 μm) made of aluminum foil. . As shown in FIGS. 2 and 3, a positive electrode current collector exposed portion 1c in which the positive electrode active material layer 1b does not exist is provided on the winding end side of the positive electrode plate 1, and the positive electrode active material layer An end 1 e on the winding end side of 1 b is covered with a separator 3. Furthermore, a low density polyethylene film (LDPE, melting point: 120 ° C.) 20 having a lower melting point than the separator 3 is attached to the battery outer surface 1 d of the positive electrode current collector exposed portion 1 c and a part of the separator 3. The negative electrode plate 2 has a structure in which a negative electrode active material layer 2b (thickness on one side: 68 μm) is formed on both surfaces of a negative electrode current collector 2a (thickness: 8 μm) made of copper foil. .

このように、正極集電体露出部１ｃの電池外側面１ｄに、融点が１２０℃の低密度ポリエチレンフィルム２０が存在することにより、通常使用する温度範囲では、金属外装缶４と正極集電体露出部１ｃとの絶縁性は保持される一方、何らかの要因で電池温度が上昇した場合には、セパレータ３の融点以下で低密度ポリエチレンフィルム２０が溶融、収縮するため、金属外装缶４と正極集電体露出部１ｃとが接触して短絡する。   As described above, the low-density polyethylene film 20 having a melting point of 120 ° C. is present on the battery outer surface 1d of the positive electrode current collector exposed portion 1c, so that the metal outer can 4 and the positive electrode current collector can be used in a normally used temperature range. While the insulation with the exposed portion 1c is maintained, when the battery temperature rises for some reason, the low-density polyethylene film 20 melts and contracts below the melting point of the separator 3, so that the metal outer can 4 and the positive electrode collector A short circuit occurs due to contact with the exposed electrical part 1c.

尚、図３では、正極集電体露出部１ｃが電池外側に変形しなければ、正極集電体露出部１ｃと金属外装缶４とが接触しないようにみえるが、上述したように、正極集電体１ａ、正極活物質層１ｂ、及びセパレータ３の厚さは極めて小さく、しかも電池の充電状態では正負両活物質が膨張しているので、巻取電極体５には金属外装缶４方向に押圧力が加わる。したがって、正極集電体露出部１ｃが変形しなくても、正極集電体露出部１ｃと金属外装缶４とが接触する。   In FIG. 3, it appears that the positive electrode current collector exposed portion 1c and the metal outer can 4 do not contact each other unless the positive electrode current collector exposed portion 1c is deformed to the outside of the battery. Since the thickness of the electric conductor 1a, the positive electrode active material layer 1b, and the separator 3 is extremely small, and both the positive and negative active materials are expanded in the charged state of the battery, the winding electrode body 5 has a metal outer can 4 direction. A pressing force is applied. Therefore, even if the positive electrode current collector exposed portion 1c is not deformed, the positive electrode current collector exposed portion 1c and the metal outer can 4 are in contact with each other.

上記構造の円筒型リチウムイオン二次電池を、以下のようにして作製した。
〔正極板の作製〕
先ず、正極活物質であるコバルト酸リチウムと、炭素導電剤としてのアセチレンブラックと、結着剤としてのＰＶＤＦとを、９５：２．５：２．５の質量比で混合した後、ＮＭＰを溶剤として特殊機化製Ｔ.Ｋ.ＣＯＮＢＩＭＩＸを用いてこれらを攪拌し、正極スラリーを調製した。次に、アルミニウム箔から成る正極集電体の両面に上記正極スラリーを塗布した後、乾燥圧延することにより正極板１を作製した。
尚、上記正極板１を作製する際、正極板端部には正極スラリーの未塗工部を配置することにより正極集電体露出部１ｃを形成した。更に、正極板１の端部にはアルミニウム製の集電タブを溶接した。 A cylindrical lithium ion secondary battery having the above structure was produced as follows.
[Preparation of positive electrode plate]
First, lithium cobaltate as a positive electrode active material, acetylene black as a carbon conductive agent, and PVDF as a binder are mixed at a mass ratio of 95: 2.5: 2.5, and then NMP is used as a solvent. These were stirred using TK CONBIMIX made by Tokushu Kika to prepare a positive electrode slurry. Next, the positive electrode slurry was applied to both surfaces of a positive electrode current collector made of an aluminum foil, and then subjected to dry rolling to prepare a positive electrode plate 1.
When the positive electrode plate 1 was produced, the positive electrode current collector exposed portion 1c was formed by arranging an uncoated portion of the positive electrode slurry at the end portion of the positive electrode plate. Further, an aluminum current collecting tab was welded to the end of the positive electrode plate 1.

〔負極板の作製〕
負極活物質である炭素材料（人造黒鉛）と、ＣＭＣ（カルボキシメチルセルロースナトリウム）と、ＳＢＲ（スチレンブタジエンゴム）とを、質量比で９８：１：１となるように、特殊機化製Ｔ.Ｋ.ＣＯＮＢＩＭＩＸを用いて水溶液中で混合して負極スラリーを作製した後、銅箔から成る負極集電体の両面に上記負極スラリーを塗着し、更に、乾燥、圧延することにより、負極集電体の両面に負極活物質層が形成された負極板２を作製した。
尚、負極板２の端部にはニッケル製の集電タブを溶接した。 (Production of negative electrode plate)
TK manufactured by Tokushu Kika Co., Ltd. has a mass ratio of carbon material (artificial graphite) which is a negative electrode active material, CMC (carboxymethyl cellulose sodium), and SBR (styrene butadiene rubber) to a mass ratio of 98: 1: 1. A negative electrode current collector was prepared by mixing in an aqueous solution using CONBMIX, and then coating the negative electrode slurry on both sides of the negative electrode current collector made of copper foil, followed by drying and rolling. The negative electrode plate 2 in which the negative electrode active material layers were formed on both sides was prepared.
A nickel current collecting tab was welded to the end of the negative electrode plate 2.

〔非水電解液の調製〕
エチレンカーボネート（ＥＣ）とメチルエチルカーボネート（ＭＥＣ）とが容積比で３：７の割合で混合された混合溶媒に、ＬｉＰＦ6を１．０モル／リットルの割合で溶解させて調製した。 (Preparation of non-aqueous electrolyte)
It was prepared by dissolving LiPF 6 at a ratio of 1.0 mol / liter in a mixed solvent in which ethylene carbonate (EC) and methyl ethyl carbonate (MEC) were mixed at a volume ratio of 3: 7.

〔電池の組立〕
正極活物質層１ｂと負極活物質層２ｂとがセパレータ３を介して対向するように、正極板１、セパレータ３及び負極板２を渦巻状に多数回巻取り、巻取電極体５を作製した。このとき、正極活物質層１ｂの端部１ｅはセパレータ３により覆われ、また、正極集電体露出部１ｃは、上記巻取電極体５の最外面に配置されている構造となっている。その後、セパレータ３の巻回終端部３ａから突出した正極集電体露出部１ｃの金属外装缶４側の面１ｄを全て覆うように低密度ポリエチレンフィルム（ＬＤＰＥ）２０を貼り付けた（尚、セパレータ３の一部にも低密度ポリエチレンフィルム２０が貼り付けられている）。 [Battery assembly]
The positive electrode plate 1, the separator 3, and the negative electrode plate 2 were wound many times in a spiral shape so that the positive electrode active material layer 1 b and the negative electrode active material layer 2 b were opposed to each other with the separator 3 therebetween. . At this time, the end 1 e of the positive electrode active material layer 1 b is covered with the separator 3, and the positive electrode current collector exposed portion 1 c is arranged on the outermost surface of the winding electrode body 5. Thereafter, a low-density polyethylene film (LDPE) 20 was attached so as to cover all the surface 1d on the metal outer can 4 side of the positive electrode current collector exposed portion 1c protruding from the winding end portion 3a of the separator 3 (note that the separator 3 is also pasted with a low-density polyethylene film 20).

次に、上記巻取電極体５を金属外装缶４に挿入し、金属外装缶４の底部に負極集電タブをスポット溶接により接合する一方、電池蓋６の底部に同様の方法にて正極集電タブを接合した。最後に、非水電解液を金属外装缶４内の巻取電極体５に注入、含浸させた後、金属外装缶４の開口部に絶縁パッキング１１を介して封口蓋６をかしめ固定することにより円筒型リチウムイオン二次電池を作製した。尚、本電池の設計容量は２５００ｍＡｈである。   Next, the winding electrode body 5 is inserted into the metal outer can 4, and the negative electrode current collecting tab is joined to the bottom of the metal outer can 4 by spot welding, while the positive electrode current collector is collected at the bottom of the battery lid 6 by the same method. The electric tab was joined. Finally, after injecting and impregnating the nonaqueous electrolyte into the winding electrode body 5 in the metal outer can 4, the sealing lid 6 is caulked and fixed to the opening of the metal outer can 4 via the insulating packing 11. A cylindrical lithium ion secondary battery was produced. In addition, the design capacity of this battery is 2500 mAh.

（実施例）
実施例としては、上記最良の形態で示した円筒型リチウムイオン二次電池を用いた。
このようにして作製した電池を、以下、本発明電池Ａと称する。 (Example)
As an example, the cylindrical lithium ion secondary battery shown in the best mode was used.
The battery thus produced is hereinafter referred to as the present invention battery A.

（比較例）
図７に示すように、上記正極集電体露出部１ｃの電池外側面１ｄが全てセパレータ３により覆われている（即ち、低密度ポリエチレンフィルム２０が存在しない）他は、上記実施例と同様にして円筒型リチウムイオン二次電池を作製した。
このようにして作製した電池を、以下、比較電池Ｚと称する。 (Comparative example)
As shown in FIG. 7, the battery outer surface 1d of the positive electrode current collector exposed portion 1c is entirely covered with the separator 3 (that is, the low-density polyethylene film 20 does not exist). Thus, a cylindrical lithium ion secondary battery was produced.
The battery thus manufactured is hereinafter referred to as a comparative battery Z.

（実験）
本発明電池Ａ及び比較電池Ｚのサーマル試験を行なったので、その結果を表１に示す。具体的な実験内容は、上記本発明電池Ａ及び比較電池Ｚを、１．０Ｉｔの電流値で電池電圧が４．２０Ｖとなるまで定電流充電を行なった後、４．２０Ｖの電圧で電流値が１／５Ｉｔになるまで充電した。その後、電気炉内で２５℃から１５０℃まで５℃／ｍｉｎの昇温速度で昇温した後、１５０℃で６０分間保持した場合の電池電圧および電池温度を測定した。 (Experiment)
Table 1 shows the results of thermal tests of the inventive battery A and the comparative battery Z. Specifically, the present invention battery A and comparative battery Z were charged at a constant current until the battery voltage reached 4.20 V at a current value of 1.0 It, and then the current value at a voltage of 4.20 V. The battery was charged until 1/5 It. Then, after raising the temperature from 25 ° C. to 150 ° C. at a rate of 5 ° C./min in an electric furnace, the battery voltage and the battery temperature when held at 150 ° C. for 60 minutes were measured.

具体的な評価は、電池の放電終止電圧である２．７５Ｖ以下に電池電圧が低下するまでの時間と、そのときの温度、及び、電池温度の異常に至った電池数とを調べた。試料数は各電池５個ずつであり、また、サーマル試験の保持温度である１５０℃以上に電池温度が上昇した場合を電池温度の異常と判断した。   Specifically, the time required for the battery voltage to drop to 2.75 V or less, which is the discharge end voltage of the battery, the temperature at that time, and the number of batteries that resulted in abnormal battery temperature were examined. The number of samples was 5 for each battery, and when the battery temperature rose to 150 ° C. or higher which is the holding temperature of the thermal test, it was determined that the battery temperature was abnormal.

尚、通常、電池にはＰＴＣ等の保護素子、保護回路が設置され、異常時の安全性が確保されるように設計されている。また、正極材料や負極材料における信頼性向上のための対策、電解液中の添加剤等、各種安全機構が用いられ、安全性は保護回路無しでも十分に確保されている。但し、今回の試験では、本発明の構成とした場合の安全性の向上を確認する目的であるということから、セパレータのシャットダウン機構を除く安全性に係わる材料／機構を極力排除してサーマル試験を行なった。   Normally, the battery is provided with a protective element such as PTC and a protective circuit, and is designed to ensure safety in the event of an abnormality. In addition, various safety mechanisms such as measures for improving the reliability of the positive electrode material and the negative electrode material and additives in the electrolytic solution are used, and safety is sufficiently ensured even without a protective circuit. However, since the purpose of this test is to confirm the improvement in safety in the case of the configuration of the present invention, the thermal test was conducted by eliminating materials / mechanisms related to safety excluding the separator shutdown mechanism as much as possible. I did it.

Figure 2010080390
Figure 2010080390

表１から明らかなように、比較電池Ｚでは、昇温開始から２９分後、電池温度１４１℃で電池電圧が２．７５Ｖ以下に低下し、昇温後６０分以内に全ての電池で電池温度の異常に至った。これに対して、本発明電池は、昇温開始から２４分後、電池温度１２４℃で電池電圧が２．７５Ｖ以下に低下し、昇温後６０分以内には全く電池温度の異常は認められなかった。   As is clear from Table 1, in Comparative Battery Z, the battery voltage decreased to 2.75 V or less at a battery temperature of 141 ° C. after 29 minutes from the start of the temperature increase, and the battery temperature of all batteries within 60 minutes after the temperature increase. It led to abnormalities. In contrast, in the battery of the present invention, after 24 minutes from the start of temperature increase, the battery voltage dropped to 2.75 V or lower at a battery temperature of 124 ° C., and no abnormality in battery temperature was observed within 60 minutes after temperature increase. There wasn't.

これは、以下に示す理由によるものと考えられる。即ち、比較電池Ｚでは、電池温度がセパレータの融点（１３４℃）に達した後、電池電圧が低下していることから、セパレータの溶融による正負極活物質同士の接触により電圧が低下し、その後、正負極活物質のショート部で局所的な温度上昇が起こり、電池温度の異常に至ったものと考えられる。
これに対して、本発明電池Ａでは、電池温度がセパレータの融点に達する前にショートに至っていることから、巻取電極体の最外周に位置した正極集電体露出部を覆う低密度ポリエチレンの溶融により、正極集電体露出部が金属外装缶（極性は負極）と接触し、ショートしたものと考えられる。このように、正極活物質層でなく、正極集電体露出部分が金属外装缶と接触することにより短絡が生じているため、正極活物質層での局所的な温度上昇は伴わず、早期に電池電圧を低下させることができたものと考えられる。そして、このように電池電圧が低下した場合には（即ち、放電状態の正極活物質及び負極活物質では）、熱的に安定であるため、１５０℃に保持しても熱分解したり、電解液と急激な発熱反応を起こすことはなく、電池温度の異常には至らなかったものと考えられる。 This is considered to be due to the following reasons. That is, in the comparative battery Z, since the battery voltage is lowered after the battery temperature reaches the melting point (134 ° C.) of the separator, the voltage is lowered by contact between the positive and negative electrode active materials due to melting of the separator, and thereafter It is considered that a local temperature rise occurred in the short part of the positive and negative electrode active materials, leading to abnormal battery temperature.
On the other hand, in the present invention battery A, since the battery temperature reaches a short before reaching the melting point of the separator, the low-density polyethylene covering the exposed portion of the positive electrode current collector located on the outermost periphery of the winding electrode body. It is considered that the exposed portion of the positive electrode current collector was brought into contact with the metal outer can (polarity is negative electrode) due to melting and short-circuited. In this way, a short circuit occurs because the exposed portion of the positive electrode current collector, not the positive electrode active material layer, is in contact with the metal outer can, so there is no local temperature rise in the positive electrode active material layer, and early It is considered that the battery voltage could be reduced. When the battery voltage decreases in this way (that is, in the discharged positive electrode active material and negative electrode active material), it is thermally stable, so that it is thermally decomposed or electrolyzed even if kept at 150 ° C. It is considered that there was no sudden exothermic reaction with the liquid and the battery temperature did not become abnormal.

これらの結果から、本発明のように、巻取電極体の最外周部に、集電体露出部が設けられた正極板（金属外装缶とは異なる極性の極板）が配置されると共に、集電体露出部の電池外側面が低密度ポリエチレン（セパレータより低融点の絶縁性フィルム）で覆われている電池構造とすることで、高温下でも信頼性の高い非水電解質二次電池を提供することができることがわかる。   From these results, as in the present invention, a positive electrode plate (electrode plate having a polarity different from that of the metal outer can) provided with a current collector exposed portion is disposed on the outermost peripheral portion of the winding electrode body, Providing a highly reliable non-aqueous electrolyte secondary battery even at high temperatures by adopting a battery structure in which the battery outer surface of the exposed part of the current collector is covered with low-density polyethylene (an insulating film having a lower melting point than the separator). You can see that you can.

〔その他の事項〕
（１）上記実施例では円筒型リチウムイオン二次電池を例にとって説明したが、本発明は、図４及び図５に示すような角型リチウムイオン二次電池にも適用することができる（尚、図４及び図５では、上記図１〜図３と同一の機能を有するものには同一の符号を付している）。但し、当該電池では、金属外装缶４は正極板１に接続される構造となっているため、巻取電極体５の最外面には負極板２を配置し、当該負極板２に負極活物質層２ｂが存在しない集電体露出部２ｃを設け、この集電体露出部２ｃの電池外側面２ｄが低密度ポリエチレンフィルム２０で覆われているような構成となっている。これにより、上述した作用効果と同様の作用効果を得ることができる。 [Other matters]
(1) In the above embodiment, a cylindrical lithium ion secondary battery has been described as an example. However, the present invention can also be applied to a prismatic lithium ion secondary battery as shown in FIGS. 4 and 5, the same reference numerals are given to the components having the same functions as those in FIGS. 1 to 3. However, in the battery, since the metal outer can 4 is connected to the positive electrode plate 1, the negative electrode plate 2 is disposed on the outermost surface of the winding electrode body 5, and the negative electrode active material is disposed on the negative electrode plate 2. A current collector exposed portion 2 c in which the layer 2 b does not exist is provided, and the battery outer surface 2 d of the current collector exposed portion 2 c is covered with the low density polyethylene film 20. Thereby, the effect similar to the effect mentioned above can be acquired.

（２）上記セパレータ３より融点の低い絶縁性フィルムとしては、上記低密度ポリエチレン（融点：１２０℃）に限定するものではなく、使用するセパレータの融点より低く、通常使用する温度領域において絶縁性があり、且つ電解液に対して安定であれば、如何なるものでも良い。但し、電池の製造段階で乾燥工程を有するので、絶縁性フィルムの融点は１１０℃以上であることが望ましい。このようなことを考慮すれば、絶縁性フィルムの融点は、一般的に、１１０〜１３０℃（特に１１０〜１２０℃）であることが望ましい。 (2) The insulating film having a melting point lower than that of the separator 3 is not limited to the low-density polyethylene (melting point: 120 ° C.), but is lower than the melting point of the separator to be used, and has an insulating property in a temperature range usually used. Any material can be used as long as it is stable to the electrolytic solution. However, since the drying process is included in the battery manufacturing stage, the melting point of the insulating film is preferably 110 ° C. or higher. Considering this, it is generally desirable that the insulating film has a melting point of 110 to 130 ° C. (particularly 110 to 120 ° C.).

また、絶縁性フィルムの厚みは通常の電池使用状態で絶縁性が保たれるような厚みであれば足る。尚、絶縁性フィルムの厚みが大きすぎると、本発明の効果が発揮され難くなるとも考えられるが、巻取電極体５と電池缶４との間のデットスペースは極めて狭いので、絶縁性フィルムの厚みを余り大きくすることはできない。このように、絶縁性フィルムの厚みが規制されているので、本発明の作用効果は円滑に発揮される。   Moreover, the thickness of an insulating film should just be a thickness which can maintain insulation in the normal battery use state. In addition, although it is thought that if the thickness of the insulating film is too large, the effect of the present invention is hardly exhibited, but since the dead space between the winding electrode body 5 and the battery can 4 is extremely narrow, The thickness cannot be increased too much. Thus, since the thickness of the insulating film is regulated, the effect of the present invention is exhibited smoothly.

更に、セパレータとしては、ポリエチレン製の微多孔膜に限定するものではなく、他のポリオレフィン系樹脂材料やフッ素系樹脂等、電池の機能を確保できれば、いかなる材料を用いても良い。また、セパレータ表面に、無機微粒子や耐熱性の樹脂を積層し、セパレータの収縮を抑制する加工を施したものを使用しても良い。   Furthermore, the separator is not limited to a polyethylene microporous film, and any material may be used as long as the function of the battery can be ensured, such as other polyolefin resin materials or fluorine resins. Moreover, you may use what laminated | stacked the inorganic fine particle and heat resistant resin on the separator surface, and gave the process which suppresses shrinkage | contraction of a separator.

（３）上記実施例では正極活物質層１ｂの巻回終端側の端部１ｅをセパレータ３で覆っているが、図６に示すように、正極活物質層１ｂの巻回終端側の端部１ｅとセパレータ３の巻回終端部３ａとが面一となり、両端部１ｅ、３ａまで低密度ポリエチレンフィルム２０を延設するような構造であっても良い。但し、この構造では、低密度ポリエチレンフィルム２０が変形した場合に、正極活物質層１ｂと金属外装缶４とが直接接触するおそれがあるので、上記実施例で示した構成とするのが好ましい。 (3) Although the end 1e on the winding end side of the positive electrode active material layer 1b is covered with the separator 3 in the above embodiment, as shown in FIG. 6, the end on the winding end side of the positive electrode active material layer 1b 1e and the winding termination | terminus part 3a of the separator 3 may become flush | planar, and the structure which extends the low density polyethylene film 20 to both ends 1e and 3a may be sufficient. However, in this structure, when the low-density polyethylene film 20 is deformed, the positive electrode active material layer 1b and the metal outer can 4 may be in direct contact with each other. Therefore, the configuration shown in the above embodiment is preferable.

（４）正極活物質としては、上記コバルト酸リチウムに限定するものではなく、ニッケル−コバルト−マンガンのリチウム複合酸化物、ニッケル−マンガン−アルミニウムのリチウム複合酸化物、ニッケル−コバルト−アルミニウムのリチウム複合酸化物等のコバルト或いはマンガンを含むリチウム複合酸化物や、スピネル型マンガン酸リチウム、オリビン型燐酸リチウム等でも良い。また、これらの正極活物質は単独で用いても良く、他の正極活物質と混合されていても良い。更に、正極スラリーの作製方法としては、上述した湿式混合に限定するものではなく、事前に正極活物質と導電剤とを乾式混合した後に、ＰＶＤＦとＮＭＰとを混合、撹絆するような方法を用いても良い。 (4) The positive electrode active material is not limited to the above lithium cobalt oxide, but is nickel-cobalt-manganese lithium composite oxide, nickel-manganese-aluminum lithium composite oxide, nickel-cobalt-aluminum lithium composite. A lithium composite oxide containing cobalt or manganese such as oxide, spinel type lithium manganate, olivine type lithium phosphate, or the like may be used. Moreover, these positive electrode active materials may be used independently and may be mixed with the other positive electrode active material. Furthermore, the method for preparing the positive electrode slurry is not limited to the wet mixing described above, and a method in which the positive electrode active material and the conductive agent are dry mixed in advance, and then PVDF and NMP are mixed and stirred. It may be used.

（５）負極活物質としては、上記人造黒鉛に限定されるものではなく、グラファイト、コークス、酸化スズ、金属リチウム、珪素、及びそれらの混合物等、リチウムイオンを挿入脱離できうるものであればその種類は問わない。 (5) The negative electrode active material is not limited to the above artificial graphite, and may be any material that can insert and desorb lithium ions, such as graphite, coke, tin oxide, metallic lithium, silicon, and a mixture thereof. The kind is not ask | required.

（６）電解液のリチウム塩としては、上記ＬｉＰＦ6に限定されるものではなく、ＬｉＢＦ4、ＬｉＮ（ＳＯ2ＣＦ3）2、ＬｉＮ（ＳＯ2Ｃ2Ｆ5）2、ＬｉＰＦ6-X（ＣnＦ2n+1）X[但し、１＜ｘ＜６、ｎ＝１又は２]等でも良く、これら２種以上を混合して使用することもできる。リチウム塩の濃度は特に限定されないが、電解液１リットル当り０．８〜１．５モルに規制するのが望ましい。また、電解液の溶媒としては上記エチレンカーボネート（ＥＣ）やメチルエチルカーボネート（ＭＥＣ）に限定するものではないが、プロピレンカーボネート（ＰＣ）、ジエチルカーボネート（ＤＥＣ）、γ−ブチロラクトン（ＧＢＬ）、ジメチルカーボネート（ＤＭＣ）等のカーボネート系溶媒が好ましく、更に好ましくは環状カーボネートと鎖状カーボネートの組合せが望ましい。 (6) The lithium salt of the electrolytic solution is not limited to the above LiPF 6 , and LiBF 4 , LiN (SO 2 CF 3 ) 2 , LiN (SO 2 C 2 F 5 ) 2 , LiPF 6-X ( C n F 2n + 1 ) X [where 1 <x <6, n = 1 or 2], etc., or a mixture of two or more of these may be used. The concentration of the lithium salt is not particularly limited, but is preferably regulated to 0.8 to 1.5 mol per liter of the electrolyte. Further, the solvent of the electrolytic solution is not limited to ethylene carbonate (EC) or methyl ethyl carbonate (MEC), but propylene carbonate (PC), diethyl carbonate (DEC), γ-butyrolactone (GBL), dimethyl carbonate. A carbonate-based solvent such as (DMC) is preferable, and a combination of a cyclic carbonate and a chain carbonate is more preferable.

（７）本発明は液系の電池に限定するものではなく、ゲル系のポリマー電池にも適用することができる。この場合のポリマー材料としては、ポリエーテル系固体高分子、ポリカーボネート系固体高分子、ポリアクリロニトリル系固体高分子、オキセタン系ポリマー、エポキシ系ポリマー及びこれらの２種以上からなる共重合体もしくは架橋した高分子若しくはＰＶＤＦが例示され、このポリマー材料とリチウム塩と電解質を組合せてゲル状にした固体電解質を用いることができる。 (7) The present invention is not limited to a liquid battery, but can be applied to a gel polymer battery. Examples of the polymer material in this case include polyether solid polymer, polycarbonate solid polymer, polyacrylonitrile solid polymer, oxetane polymer, epoxy polymer, a copolymer composed of two or more of these, or a crosslinked polymer. A molecule or PVDF is exemplified, and a solid electrolyte in which this polymer material, a lithium salt, and an electrolyte are combined into a gel can be used.

（８）本発明はリチウムイオン二次電池等の非水電解質二次電池に限定されるものではなく、ニッケル−水素蓄電池等、その他の種類の電池にも用いることができる。 (8) The present invention is not limited to non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries, and can be used for other types of batteries such as nickel-hydrogen storage batteries.

本発明は、例えば携帯電話、ノートパソコン、ＰＤＡ等の移動情報端末の駆動電源のみならず、電動工具等のパワーツール電源、電気自動車やハイブリッド自動車の車載用電源等の大型電池にも適用することが出来る。   The present invention is applicable not only to driving power sources for mobile information terminals such as mobile phones, notebook computers, and PDAs, but also to large-sized batteries such as power tool power sources such as electric tools, and in-vehicle power sources for electric vehicles and hybrid vehicles. I can do it.

本発明の一例に係る円筒型リチウムイオン二次電池の半断面斜視図である。It is a half cross-sectional perspective view of the cylindrical lithium ion secondary battery which concerns on an example of this invention. 図１の電池の巻取電極体の斜視図である。It is a perspective view of the winding electrode body of the battery of FIG. 図１の電池の要部断面図である。It is principal part sectional drawing of the battery of FIG. 本発明の一例に係る角型リチウムイオン二次電池の断面図である。It is sectional drawing of the square lithium ion secondary battery which concerns on an example of this invention. 図４の電池の要部断面図である。It is principal part sectional drawing of the battery of FIG. 本発明の変形例を示す要部断面図である。It is principal part sectional drawing which shows the modification of this invention. 比較電池の要部断面図である。It is principal part sectional drawing of a comparative battery.

符号の説明Explanation of symbols

１：正極板
１ａ：正極集電体
１ｂ：正極活物質層
１ｃ：正極集電体露出部
２：負極
３：セパレータ
４：金属外装缶
５：巻取電極体
２０：低密度ポリエチレンフィルム DESCRIPTION OF SYMBOLS 1: Positive electrode plate 1a: Positive electrode collector 1b: Positive electrode active material layer 1c: Positive electrode collector exposed part 2: Negative electrode 3: Separator 4: Metal exterior can 5: Winding electrode body 20: Low density polyethylene film

Claims (3)

正極集電体の表面に正極活物質層が形成された正極板と、負極集電体の表面に負極活物質層が形成された負極板とが、セパレータを介して渦巻状に巻回された巻取電極体を有し、この巻取電極体が金属外装缶内に収納されると共に、この金属外装缶と上記両極板のうち一方の極板とが電気的に接続された構造の電池において、
上記巻取電極体の最外周部には、上記セパレータを介して上記金属外装缶とは異なる極性の極板が配置されると共に、当該極板の最外周部における巻回終端側には、上記セパレータの巻回終端部よりも突出し、上記活物質層が存在しない集電体露出部が設けられ、しかも、この集電体露出部の電池外側面が上記セパレータより低融点で且つ製造段階での乾燥工程における乾燥温度よりも高融点の絶縁性フィルムで覆われていることを特徴とする電池。 A positive electrode plate having a positive electrode active material layer formed on the surface of the positive electrode current collector and a negative electrode plate having a negative electrode active material layer formed on the surface of the negative electrode current collector were spirally wound through a separator. In a battery having a structure having a winding electrode body, the winding electrode body being housed in a metal outer can, and the metal outer can and one of the two electrode plates being electrically connected ,
A pole plate having a polarity different from that of the metal outer can is disposed on the outermost peripheral portion of the winding electrode body via the separator, and on the winding end side in the outermost peripheral portion of the electrode plate, A current collector exposed portion that protrudes beyond the winding end portion of the separator and does not have the active material layer is provided, and the battery outer surface of the current collector exposed portion has a lower melting point than the separator and in the manufacturing stage. A battery characterized by being covered with an insulating film having a melting point higher than the drying temperature in the drying step. 上記金属外装缶とは異なる極性の極板において、活物質層の巻回終端側の端部は、上記セパレータで覆われている、請求項１に記載の電池。   The battery according to claim 1, wherein an end of the active material layer on the winding end side is covered with the separator in an electrode plate having a polarity different from that of the metal outer can. 上記正極活物質層の活物質及び上記負極活物質層の活物質として、リチウムイオンを挿入脱離できうるものを用いる、請求項１又は２に記載の電池。   The battery according to claim 1, wherein a material capable of inserting and extracting lithium ions is used as an active material of the positive electrode active material layer and an active material of the negative electrode active material layer.
JP2008250178A 2008-09-29 2008-09-29 Battery Withdrawn JP2010080390A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010212086A (en) * 2009-03-10 2010-09-24 Sanyo Electric Co Ltd Nonaqueous electrolyte secondary battery
JP2013004195A (en) * 2011-06-13 2013-01-07 Toyota Motor Corp Wound type battery, and manufacturing method of the same

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010212086A (en) * 2009-03-10 2010-09-24 Sanyo Electric Co Ltd Nonaqueous electrolyte secondary battery
JP2013004195A (en) * 2011-06-13 2013-01-07 Toyota Motor Corp Wound type battery, and manufacturing method of the same

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