JP2006032112A - Electrochemical element - Google Patents

Electrochemical element Download PDF

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JP2006032112A
JP2006032112A JP2004208960A JP2004208960A JP2006032112A JP 2006032112 A JP2006032112 A JP 2006032112A JP 2004208960 A JP2004208960 A JP 2004208960A JP 2004208960 A JP2004208960 A JP 2004208960A JP 2006032112 A JP2006032112 A JP 2006032112A
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current collector
electrode plate
active material
positive electrode
plate
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Naoto Arai
直人 荒井
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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
    • 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
    • Y02E60/13—Energy storage using capacitors
    • 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 an electrochemical element having stable electrical connection between a collector part and a collector plate and capable of sufficiently securing welding strength between a collector body and the collector plate, and of preventing an internal short circuit. <P>SOLUTION: A collector body exposure part 9 without applying an active material thereto is formed on a positive electrode plate 1 composed by applying an active material to a strip-like collector body; a resin coating 13 is formed on the base part of the collector body exposure part 9; a collector body exposure part 12 without applying an active material thereto is formed on a negative electrode plate 2 composed by applying an active material to a strip-like collector body; and a resin coating 14 is formed on the base part of the collector body exposure part 12. The collector body exposure parts 9 and 12 projected on both ends when an electrode plate group 4 is formed by rolling both the electrode plates by disposing a separator between them are pressed to form welding surfaces, and a positive electrode collector plate 10 and a negative electrode collector plate 11 are respectively welded to them. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、電池、電気二重層コンデンサなどの極板を巻回構造に構成した電気化学素子に関するものである。   The present invention relates to an electrochemical element in which an electrode plate such as a battery or an electric double layer capacitor is configured in a wound structure.

電池、電気二重層コンデンサ等の電気化学素子においては、極板を巻回構造に構成したものが広く用いられている。即ち、帯状の集電体に活物質が塗着された正極板と、帯状の集電体に活物質が塗着された負極板との間に帯状のセパレータを配して渦巻き状に巻回して極板群に形成している。この極板群が電解質と共に金属容器内に収容され、極板群の上下両端面もしくは一端面から正負何れかの極板の集電体を突出させ、この集電体に集電板が接合され、集電板は正極又は負極の外部接続端子となる部位に接続される。   2. Description of the Related Art Electrochemical elements such as batteries and electric double layer capacitors are widely used in which electrode plates are configured in a wound structure. In other words, a strip-shaped separator is disposed between a positive electrode plate in which an active material is applied to a strip-shaped current collector and a negative electrode plate in which an active material is coated to a strip-shaped current collector, and is wound in a spiral shape. Are formed into electrode plates. The electrode plate group is housed in a metal container together with the electrolyte, and a current collector of either positive or negative electrode plate is projected from both the upper and lower end surfaces or one end surface of the electrode plate group, and the current collector plate is joined to the current collector. The current collector plate is connected to a portion serving as a positive or negative external connection terminal.

集電体と集電板との間の接合は、接合強度を強化させると共に、集電効率を向上させて充放電時の温度上昇を抑制するために、集電体の多点を集電板に接合することが要求されている。また、携帯機器や移動体などのように振動や衝撃が加わる機器に適用すると、極板群が受ける振動や衝撃によって接続部に破断や剥離が生じやすくなるため、集電体から外部接続端子に至る接続強度を向上させた接続構造が求められている。   The junction between the current collector and the current collector plate enhances the joint strength and improves the current collection efficiency and suppresses the temperature rise during charging and discharging. It is required to be bonded to. In addition, when applied to devices that are subject to vibration or impact, such as portable devices or moving objects, the connection part is liable to break or peel off due to vibration or impact received by the electrode plate group. There is a need for a connection structure with improved connection strength.

これを実現する従来技術として、極板群の端部から突出している集電体を押圧して折り曲げ、平坦な溶接面を形成した上に集電板を配し、集電体と集電板との間を平坦な溶接面で溶接するようにした構成が知られている（特許文献１参照）。   As a conventional technique for realizing this, the current collector protruding from the end of the electrode plate group is pressed and bent to form a flat weld surface, and then the current collector is arranged. The current collector and the current collector A configuration is known in which welding is performed with a flat welding surface (see Patent Document 1).

また、極板群の端部から突出させた集電体が互いに重なり合うように折り曲げて平坦な面を形成し、この平坦面に集電板を溶接する構造が提案されている（特許文献２参照）。
特開２０００−２９４２２２号公報 特開２０００−３２３１１７号公報 Further, a structure has been proposed in which current collectors protruding from the ends of the electrode plate group are bent so as to overlap each other to form a flat surface, and the current collector plate is welded to the flat surface (see Patent Document 2). ).
JP 2000-294222 A JP 2000-323117 A

しかしながら、上記従来技術においては、集電体によって形成された平坦面に集電板を接合する際の加圧による変形が考慮されていなかった。即ち、集電体は極めて薄い箔状金属板であるため、溶接時の加圧を受けると座屈が生じやすく、溶接が一定状態になされないばかりでなく、座屈した部分が正極板と負極板との間を隔離するセパレータを突き抜けて異極の極板に接触して内部短絡を発生させる恐れがあった。   However, in the above prior art, deformation due to pressurization when a current collector plate is joined to a flat surface formed by a current collector has not been considered. That is, since the current collector is a very thin foil-like metal plate, buckling is likely to occur when pressure is applied during welding, and not only the welding is not performed in a constant state, but also the buckled portions are the positive electrode plate and the negative electrode. There is a risk of causing an internal short circuit by penetrating a separator that separates from the plate and coming into contact with an electrode plate of a different polarity.

本発明は上記従来技術の課題に鑑みて創案されたもので、その目的とするところは、溶接時の加圧によって集電体に座屈が生じ難く正負極間の絶縁性を向上させる構造を備えた電気化学素子を提供することにある。   The present invention was devised in view of the above-mentioned problems of the prior art, and its object is to provide a structure that improves the insulation between the positive and negative electrodes so that the current collector is unlikely to buckle by pressurization during welding. It is to provide an electrochemical device provided.

上記目的を達成するための本発明は、帯状の集電体に活物質が塗着された正極板と、帯状の集電体に活物質が塗着された負極板とを、正極板及び負極板より大きな幅に形成された帯状のセパレータを介して巻回した極板群に形成し、前記極板群を容器内に収容されてなる電気化学素子であって、前記正極板及び／又は負極板の集電体は、その幅方向の一方端側に活物質が塗着されない集電体露出部が形成され、集電体露出部はその幅方向のセパレータの幅と略同一位置に至るまでの部位が絶縁被覆されてなり、前記極板群に形成したとき端部から突出した集電体露出部を押圧して折り曲げ形成された溶接面に集電板が溶接されてなることを特徴とするものである。   In order to achieve the above object, the present invention provides a positive electrode plate in which an active material is applied to a strip-shaped current collector, and a negative electrode plate in which an active material is applied to a strip-shaped current collector. An electrochemical element formed in an electrode plate group wound through a strip-shaped separator formed to have a larger width than the plate, and the electrode plate group is accommodated in a container, the positive electrode plate and / or the negative electrode The current collector of the plate is formed with a current collector exposed portion not coated with an active material on one end side in the width direction until the current collector exposed portion reaches substantially the same position as the width of the separator in the width direction. And the current collector plate is welded to a welding surface formed by pressing and bending the current collector exposed portion protruding from the end when formed in the electrode plate group. To do.

上記構成によれば、集電体露出部の基部は絶縁被覆によって補強されるので、溶接面を形成する際の押圧や溶接時の加圧、あるいは外部からの振動や衝撃を受けたときに集電体露出部が座屈することが防止できる。集電体露出部に座屈が生じると溶接面が一定高さに形成されないため溶接強度が低下し、座屈した集電体露出部がセパレータを突き抜けて異極に接触して内部短絡を発生させる恐れがあるが、絶縁被覆の形成によって溶接強度及び絶縁性が強化されるので、振動や衝撃を受けやすい携帯機器や移動体などの電池電源に適用することが可能な電気化学素子に構成することができる。   According to the above configuration, the base portion of the current collector exposed portion is reinforced by the insulation coating, so that it collects when it is subjected to pressing during forming the welding surface, pressing during welding, or external vibration or impact. It can prevent that an electric body exposure part buckles. If buckling occurs in the current collector exposed part, the weld surface is not formed at a constant height, so the welding strength decreases, and the buckled current collector exposed part penetrates the separator and contacts a different electrode, causing an internal short circuit. Although the welding strength and insulation are enhanced by the formation of the insulation coating, it is configured as an electrochemical element that can be applied to battery power sources such as portable devices and mobile objects that are susceptible to vibration and impact. be able to.

上記構成において、溶接面は、集電体露出部が絶縁被覆の形成部位の直近位置で折れ曲がるように押圧して形成することにより、溶接面は絶縁被覆及びセパレータの端面で支持される状態となり、溶接面を安定した状態に形成して接合強度を向上させることができ、より座屈が発生し難い構造が得られる。   In the above configuration, the welding surface is pressed and formed so that the current collector exposed portion is bent at a position closest to the insulating coating forming portion, so that the welding surface is supported by the insulating coating and the end face of the separator, The weld surface can be formed in a stable state to improve the joint strength, and a structure in which buckling is less likely to occur can be obtained.

また、絶縁被覆は、活物質の塗着厚さと略同一に形成することにより、集電体露出部はセパレータの間に絶縁被覆により安定して保持される。この絶縁被覆は、絶縁性樹脂の塗布あるいは絶縁性テープの貼着により形成することができる。   Further, the insulating coating is formed to be substantially the same as the thickness of the active material, so that the current collector exposed portion is stably held by the insulating coating between the separators. This insulating coating can be formed by applying an insulating resin or attaching an insulating tape.

本発明によれば、集電板との接合面である溶接面を形成する押圧時や溶接時の加圧、更には外部からの衝撃等によって集電体露出部が座屈し難くなるので、電気的な接続が確実で安定になされ、座屈による内部短絡の発生を抑制できる高品質の電気化学素子を得ることができる。   According to the present invention, the exposed portion of the current collector is less likely to buckle due to pressing or forming pressure during welding to form a weld surface that is a joint surface with the current collector plate, and further due to external impact or the like. Connection can be made reliably and stably, and a high-quality electrochemical device capable of suppressing the occurrence of internal short circuit due to buckling can be obtained.

本実施形態は、電気化学素子の一例であるリチウムイオン二次電池に本発明の構成を適用した例を示すものである。   The present embodiment shows an example in which the configuration of the present invention is applied to a lithium ion secondary battery which is an example of an electrochemical element.

図１において、実施形態に係るリチウムイオン二次電池は、帯状の正極集電体１ａに活物質１ｂが塗布された正極板１と、帯状の負極集電体２ａに活物質２ｂが塗布された負極板２とを微多孔ポリエチレンフィルムから成るセパレータ３を間に配して渦巻き状に巻回して極板群４が構成されている。この極板群４を電解液と共に電池缶６内に収納し、電池缶６の開口部はガスケット８を介して封口板７によって封口される。本構成においては、電池缶６が負極外部接続端子となり、封口板７が正極外部接続端子となっている。   1, the lithium ion secondary battery according to the embodiment has a positive electrode plate 1 in which an active material 1b is applied to a strip-shaped positive electrode current collector 1a, and an active material 2b is applied to a strip-shaped negative electrode current collector 2a. An electrode plate group 4 is configured by winding the negative electrode plate 2 in a spiral shape with a separator 3 made of a microporous polyethylene film interposed therebetween. The electrode plate group 4 is accommodated in the battery can 6 together with the electrolytic solution, and the opening of the battery can 6 is sealed by the sealing plate 7 via the gasket 8. In this configuration, the battery can 6 serves as a negative electrode external connection terminal, and the sealing plate 7 serves as a positive electrode external connection terminal.

正極板１は、図２（ａ）に示すように、アルミニウム箔によって帯状に形成された正極集電体１ａの幅方向の一方端側に集電体露出部９を残して両面に正極活物質１ｂを塗着し、集電体露出部９の活物質塗着面側に樹脂被覆１３を設けて構成されている。また、負極板２は、図２（ｂ）に示すように、銅箔によって帯状に形成された負極集電体２ａの幅方向の他方端側に集電体露出部１２を残して両面に負極活物質２ｂを塗着し、集電体露出部１２の活物質塗着面側に樹脂被覆１４を設けて構成されている。また、セパレータ３は、正極板１及び負極板２の活物質塗着部位より大きな幅の帯状に形成されている。   As shown in FIG. 2 (a), the positive electrode plate 1 has a positive electrode active material on both surfaces, leaving a current collector exposed portion 9 on one end side in the width direction of the positive electrode current collector 1a formed in a strip shape by an aluminum foil. 1b is applied, and the resin coating 13 is provided on the active material application surface side of the current collector exposed portion 9. Further, as shown in FIG. 2 (b), the negative electrode plate 2 has a negative electrode on both surfaces, leaving a current collector exposed portion 12 on the other end side in the width direction of the negative electrode current collector 2a formed of a copper foil in a strip shape. The active material 2b is applied, and the resin coating 14 is provided on the active material application surface side of the current collector exposed portion 12. Further, the separator 3 is formed in a band shape having a width larger than that of the active material application site of the positive electrode plate 1 and the negative electrode plate 2.

より具体的には、正極板１は、電解二酸化マンガン（ＭｎＯ2）と炭酸リチウム（Ｌｉ2ＣＯ3）とをＬｉ／Ｍｎ＝１／２となるように混合し、８００℃で２０時間大気中で焼成したＬｉＭｎ2Ｏ4と、導電剤のアセチレンブラックと、結着剤のポリフッ化ビニリデンとを、それぞれ重量比で９２：３：５の割合で混合したものを正極活物質１ｂとしている。また、正極活物質１ｂをペースト状に混練するため、結着剤としてのポリフッ化ビニリデンは溶媒であるｎ−メチルピロリドン（ＮＭＰ）に溶解した液を用いている。尚、上記混合比率は固形分としての割合である。この正極活物質１ｂのペーストを、厚み１５μｍのアルミニウム箔から成る正極集電体１ａの両面に、一側縁部に幅５ｍｍの非塗布部を残した状態で塗布して正極活物質１ｂ層を形成し、極板寸法は幅５５ｍｍ長さ５７０ｍｍとした。正極活物質１ｂ層の両面の膜厚みは同じで、塗布、乾燥後の両面の膜厚みの総和は２８０μｍとし、正極板１の厚みが２００μｍになるように圧縮成形した。 More specifically, the positive electrode plate 1 is obtained by mixing electrolytic manganese dioxide (MnO 2 ) and lithium carbonate (Li 2 CO 3 ) so that Li / Mn = 1/2, and in the atmosphere at 800 ° C. for 20 hours. The positive electrode active material 1b is obtained by mixing LiMn 2 O 4 baked in Step 1 , acetylene black as a conductive agent, and polyvinylidene fluoride as a binder in a weight ratio of 92: 3: 5, respectively. Further, in order to knead the positive electrode active material 1b in a paste form, polyvinylidene fluoride as a binder is a solution dissolved in n-methylpyrrolidone (NMP) as a solvent. In addition, the said mixing ratio is a ratio as solid content. The positive electrode active material 1b layer was formed by applying the paste of the positive electrode active material 1b on both surfaces of the positive electrode current collector 1a made of an aluminum foil having a thickness of 15 μm, leaving a non-coated portion having a width of 5 mm on one side edge. The electrode plate dimensions were 55 mm wide and 570 mm long. The positive electrode active material 1b layer was compression-molded so that the thickness of both surfaces of the positive electrode active material 1b layer was the same, the total film thickness of both surfaces after coating and drying was 280 μm, and the thickness of the positive electrode plate 1 was 200 μm.

負極板２は、人造黒鉛と結着剤のスチレンブタジエンゴム（ＳＢＲ）とを重量比９７：３の割合で混合したものを負極活物質２ｂとしている。また、負極活物質２ｂをペースト状に混練するため、結着剤としてのスチレンブタジエンゴムは水溶性のディスパージョン液を用いている。尚、上記混合比率は固形分としての割合である。この負極活物質２ｂのペーストを、厚み１４μｍの銅箔から成る負極集電体２ａの両面に、一側縁部に幅３ｍｍの非塗布部を残した状態で塗布して負極活物質２ｂ層を形成し、極板寸法は幅５７ｍｍ長さ６００ｍｍとし、負極板２の厚みが１７０μｍになるように圧縮成形している。   The negative electrode plate 2 is made by mixing artificial graphite and a binder styrene butadiene rubber (SBR) in a weight ratio of 97: 3 as a negative electrode active material 2b. Further, in order to knead the negative electrode active material 2b in a paste form, a water-soluble dispersion liquid is used for the styrene butadiene rubber as a binder. In addition, the said mixing ratio is a ratio as solid content. The negative electrode active material 2b layer was formed by applying the paste of the negative electrode active material 2b on both sides of the negative electrode current collector 2a made of a copper foil having a thickness of 14 μm, leaving a non-coated portion having a width of 3 mm on one side edge. The electrode plate is formed by compression so that the dimensions of the electrode plate are 57 mm wide and 600 mm long, and the thickness of the negative electrode plate 2 is 170 μm.

上記構成になる正極板１及び負極板２は、極板群４に形成したとき、図１に示すように、極板群４の一方端から正極集電体１ａの集電体露出部９が突出し、他方端から負極集電体２ａの集電体露出部１２が突出するようにセパレータ３を介して巻回される。図示するように前記正極板１の樹脂被覆１３及び負極板２の樹脂被覆１４は、活物質塗着層の厚さと同等の厚さで、セパレータ３の幅と略同一の幅方向位置までの幅に形成されている。   When the positive electrode plate 1 and the negative electrode plate 2 configured as described above are formed in the electrode plate group 4, the current collector exposed portion 9 of the positive electrode current collector 1a extends from one end of the electrode plate group 4 as shown in FIG. It protrudes and it winds through the separator 3 so that the collector exposed part 12 of the negative electrode collector 2a may protrude from the other end. As shown in the figure, the resin coating 13 of the positive electrode plate 1 and the resin coating 14 of the negative electrode plate 2 have the same thickness as that of the active material coating layer, and the width to the position in the width direction substantially the same as the width of the separator 3. Is formed.

極板群４の一端から突出した正極板１の集電体露出部９及び他端から突出した負極板２の集電体露出部１２は、それぞれ一定高さになるように押圧されることにより図示するように折り曲げられる。この押圧により折り曲げられた正極板１の集電体露出部９上には、正極集電板１０が超音波溶接され、負極板２の集電体露出部１２上には、負極集電板1１が抵抗溶接される。この正極集電板１０と負極集電板１１を接合した極板群４は電池缶６内に収容され、負極集電板１１と電池缶６の底部との間を抵抗溶接し、正極集電板１０から引き出した正極接続片１０ａを封口板７にレーザ溶接した後に、電池缶６内に電解液を注入して真空含浸させた後、電池缶６の開口部は封口板７によって封口され、リチウムイオン二次電池として完成する。   The current collector exposed portion 9 of the positive electrode plate 1 protruding from one end of the electrode plate group 4 and the current collector exposed portion 12 of the negative electrode plate 2 protruding from the other end are pressed so as to have a constant height, respectively. It is bent as shown. On the current collector exposed portion 9 of the positive electrode plate 1 bent by this pressing, the positive electrode current collector plate 10 is ultrasonically welded, and on the current collector exposed portion 12 of the negative electrode plate 2, the negative electrode current collector plate 11. Is resistance welded. The electrode plate group 4 in which the positive electrode current collector plate 10 and the negative electrode current collector plate 11 are joined is housed in a battery can 6, and resistance welding is performed between the negative electrode current collector plate 11 and the bottom of the battery can 6, thereby collecting the positive electrode current collector. After the positive electrode connection piece 10a pulled out from the plate 10 is laser welded to the sealing plate 7, the electrolyte is poured into the battery can 6 and vacuum impregnated, and then the opening of the battery can 6 is sealed by the sealing plate 7. Completed as a lithium ion secondary battery.

上記構成により、正極板１の集電体露出部９及び負極板２の集電体露出部１２に押圧を加えて正極集電板１０及び負極集電板１１との溶接面を形成するとき、集電体露出部９，１２それぞれの基部に樹脂被覆１３，１４が設けられていることにより集電体露出部９，１２の基部が補強されるので、押圧によって集電体露出部９，１２が基部から座屈することがなく、また、溶接時の加圧によって集電体露出部９，１２が座屈することがないので、座屈して溶接面の高さ位置が不揃いになることや、座屈した集電体露出部９，１２がセパレータ３を突き破って異極極板に接触する内部短絡の発生を防止することができる。また、当該電池を携帯機器や移動体などの電池電源として適用したとき、振動や衝撃を受けることによって集電体露出部９，１２が座屈することがなく、振動や衝撃に対する接合強度を確保した電池とすることができる。   With the above configuration, when the current collector exposed portion 9 of the positive electrode plate 1 and the current collector exposed portion 12 of the negative electrode plate 2 are pressed to form a welded surface between the positive electrode current collector plate 10 and the negative electrode current collector plate 11, Since the base portions of the current collector exposed portions 9 and 12 are reinforced by providing the resin coatings 13 and 14 at the base portions of the current collector exposed portions 9 and 12, respectively, the current collector exposed portions 9 and 12 are pressed by pressing. Is not buckled from the base, and the current collector exposed portions 9 and 12 are not buckled by the pressurization during welding, so that the height position of the weld surface becomes uneven due to buckling, It is possible to prevent the occurrence of an internal short circuit in which the bent current collector exposed portions 9 and 12 break through the separator 3 and contact the different electrode plate. In addition, when the battery is applied as a battery power source for a portable device or a moving body, the current collector exposed portions 9 and 12 are not buckled by receiving vibration or impact, and the bonding strength against vibration or impact is ensured. It can be a battery.

また、上記構成において、集電体露出部９，１２を押圧して折り曲げるとき、折れ曲がる位置が樹脂被覆１３，１４が設けられた集電体露出部９，１２の基部となるように押圧力を加えると、図３に示すように、集電体露出部９，１２は樹脂被覆１３，１４及びセパレータ３上に折り曲げられるので、溶接面がより安定した状態となり、溶接時の加圧によってより座屈が発生しにくい構造が得られる。また、溶接位置が安定してより強固な接合がなされるため、振動や衝撃に対する強度を向上させることができる。   In the above configuration, when the current collector exposed portions 9 and 12 are pressed and bent, a pressing force is applied so that the bent position becomes the base of the current collector exposed portions 9 and 12 provided with the resin coatings 13 and 14. In addition, as shown in FIG. 3, the current collector exposed portions 9 and 12 are bent on the resin coatings 13 and 14 and the separator 3, so that the welding surface becomes more stable and more seated by pressurization during welding. A structure in which bending is unlikely to occur is obtained. In addition, since the welding position is stable and stronger joining is performed, the strength against vibration and impact can be improved.

以上説明した構成における樹脂被覆１３，１４は、絶縁性樹脂を塗布して形成されるが、絶縁性のテープを貼着することによって形成することもできる。   The resin coatings 13 and 14 in the configuration described above are formed by applying an insulating resin, but can also be formed by sticking an insulating tape.

上記構成になるリチウムイオン電池の耐衝撃強度を検証するために落下試験を実施した結果を以下に示す。実施例に係る電池１００個と、比較例とする電池１００個について、高さ７５ｃｍから電池の正立・倒立・側面方向にそれぞれ一回ずつ落下させることを１サイクルとした。尚、比較例とする電池は、集電体露出部９，１２の基部に樹脂被覆１３，１４を形成していないもので、その他の構成は実施例構成と同一とした。   The results of performing a drop test in order to verify the impact strength of the lithium ion battery configured as described above are shown below. One cycle of 100 batteries according to the example and 100 batteries as comparative examples was dropped once from the height of 75 cm in the upright, inverted, and side directions of the battery. In addition, the battery used as the comparative example is one in which the resin coatings 13 and 14 are not formed on the bases of the current collector exposed portions 9 and 12, and the other configurations are the same as those in the embodiment.

検証は、１サイクル毎に電池の開回路電圧値を測定し、集電体露出部９，１２の座屈によってセパレータ３を突き破って異極極板と内部短絡したか否かを判断した。電池の開回路電圧値が降下した時を内部短絡したものと見なし、電池の開回路電圧値が降下した時のサイクル数を比較評価した。また、電池の開回路電圧値が降下した電池については、分解解析することにより、内部短絡個所を確認して内部短絡した電池のみをカウントした。この落下試験の結果を表１に示す。   In the verification, the open circuit voltage value of the battery was measured every cycle, and it was determined whether or not the separator 3 was broken by the buckling of the current collector exposed portions 9 and 12 so as to be internally short-circuited with the heteropolar plate. When the open circuit voltage value of the battery dropped, it was regarded as an internal short circuit, and the number of cycles when the open circuit voltage value of the battery dropped was compared and evaluated. Moreover, about the battery in which the open circuit voltage value of the battery fell, the internal short-circuit location was confirmed by carrying out decomposition | disassembly analysis, and only the battery short-circuited internally was counted. The results of this drop test are shown in Table 1.

Figure 2006032112
表１からわかるように、実施例の電池は７０サイクルで初めて電池の内部抵抗値が上昇したのに対し、比較例の電池では３０サイクルで電池の開回路電圧値が降下が観察された。これは、実施例構造の電池の方が集電体露出部９，１２が座屈し難くなっている構造が寄与していると考えられる。
Figure 2006032112
 As can be seen from Table 1, the internal resistance of the battery of the example increased for the first time at 70 cycles, whereas the open circuit voltage value of the battery decreased at 30 cycles for the battery of the comparative example. This is considered to be due to the structure in which the current collector exposed portions 9 and 12 are less likely to buckle in the battery of the example structure.

尚、上記構成では正極板１及び負極板２の両方に樹脂被覆１３，１４を設けているが、いずれか一方だけでも効果が得られるものである。   In the above configuration, the resin coatings 13 and 14 are provided on both the positive electrode plate 1 and the negative electrode plate 2, but the effect can be obtained by only one of them.

また、リチウムイオン二次電池に適用した例について説明したが、他の種類の電池や電気二重層コンデンサなどの電気化学素子に同様の構成を適用することができる。   Moreover, although the example applied to the lithium ion secondary battery was demonstrated, the same structure can be applied to electrochemical elements, such as another kind of battery and an electric double layer capacitor.

以上説明した通り本発明によれば、集電板を溶接するための溶接面を形成するための加圧時、溶接に必要な加圧時及び外部から受ける振動や衝撃によって集電体露出部が座屈し難く、座屈によって内部短絡を発生させることが抑制されるので、携帯機器や移動体などの電池電源として適用するのに好適な電気化学素子を構成することができる。   As described above, according to the present invention, the collector exposed portion is formed by pressurization for forming a welding surface for welding the current collector plate, pressurization necessary for welding, and vibration or impact received from the outside. Since it is difficult to buckle and the occurrence of an internal short circuit due to buckling is suppressed, an electrochemical element suitable for application as a battery power source for a portable device or a moving body can be configured.

実施形態に係るリチウムイオン二次電池の構成を示す模式図。The schematic diagram which shows the structure of the lithium ion secondary battery which concerns on embodiment. 同上構成における正極板（ａ）及び負極板（ｂ）の構成を示す断面図及び平面図。Sectional drawing and top view which show the structure of the positive electrode plate (a) and negative electrode plate (b) in a structure same as the above. 実施形態に係るリチウムイオン二次電池の変形例構成を示す模式図。The schematic diagram which shows the modification structure of the lithium ion secondary battery which concerns on embodiment.

符号の説明Explanation of symbols

１ 正極板
１ａ 正極集電体
１ｂ 正極活物質
２ 負極板
２ａ 負極集電体
２ｂ 負極活物質
３ セパレータ
４ 極板群
６ 電池缶
９、１２ 集電体露出部
１０ 正極集電板
１１ 負極集電板
１３、１４ 樹脂被覆 DESCRIPTION OF SYMBOLS 1 Positive electrode plate 1a Positive electrode collector 1b Positive electrode active material 2 Negative electrode plate 2a Negative electrode collector 2b Negative electrode active material 3 Separator 4 Electrode plate group 6 Battery can 9, 12 Current collector exposed part 10 Positive electrode current collector 11 Negative electrode current collector Board 13, 14 Resin coating

Claims (5)

帯状の集電体に活物質が塗着された正極板と、帯状の集電体に活物質が塗着された負極板とを、正極板及び負極板より大きな幅に形成された帯状のセパレータを介して巻回した極板群に形成し、前記極板群を容器内に収容してなる電気化学素子であって、
前記正極板及び／又は負極板の集電体は、その幅方向の一方端側に活物質が塗着されない集電体露出部が形成され、集電体露出部はその幅方向の活物質塗着端からセパレータの幅と略同一位置に至るまでの部位が絶縁被覆されてなり、前記極板群に形成したとき端部から突出した集電体露出部を押圧して折り曲げ形成された溶接面に集電板が溶接されてなることを特徴とする電気化学素子。 A strip-shaped separator in which a positive electrode plate in which an active material is coated on a strip-shaped current collector and a negative electrode plate in which an active material is coated on a strip-shaped current collector are formed to have a larger width than the positive electrode plate and the negative electrode plate Formed in an electrode plate group wound through, and an electrochemical element formed by housing the electrode plate group in a container,
In the current collector of the positive electrode plate and / or the negative electrode plate, a current collector exposed portion to which no active material is applied is formed on one end side in the width direction, and the current collector exposed portion is coated with the active material in the width direction. A welded surface formed by insulatingly coating a portion from the landing end to a position substantially the same as the width of the separator, and bending the exposed current collector protruding from the end when formed on the electrode plate group An electrochemical element, wherein a current collector plate is welded to the electrochemical element. 溶接面は、集電体露出部が絶縁被覆の形成部位の直近位置で折れ曲がるように押圧して形成されてなる請求項１に記載の電気化学素子。 The electrochemical device according to claim 1, wherein the welding surface is formed by pressing the current collector exposed portion so that the current collector exposed portion is bent at a position closest to the insulating coating forming portion. 絶縁被覆は、活物質の塗着厚さと略同一に形成されてなる請求項１又は２に記載の電気化学素子。 The electrochemical device according to claim 1, wherein the insulating coating is formed to have substantially the same thickness as that of the active material. 絶縁被覆は、絶縁性樹脂の塗布により形成されてなる請求項１〜３いずれか一項に記載の電気化学素子。 The electrochemical device according to claim 1, wherein the insulating coating is formed by applying an insulating resin. 絶縁被覆は、絶縁性テープの貼着により形成されてなる請求項１〜３いずれか一項に記載の電気化学素子。


The electrochemical device according to any one of claims 1 to 3, wherein the insulating coating is formed by sticking an insulating tape.


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JPWO2021020279A1 (en) * 2019-07-30 2021-02-04
CN114175390A (en) * 2019-07-30 2022-03-11 株式会社村田制作所 Secondary battery, battery pack, electronic device, electric power tool, electric aircraft, and electric vehicle
CN114207906A (en) * 2019-07-30 2022-03-18 株式会社村田制作所 Secondary battery, battery pack, electronic device, electric power tool, electric aircraft, and electric vehicle
JP7363900B2 (en) 2019-07-30 2023-10-18 株式会社村田製作所 Secondary batteries, battery packs, electronic equipment, power tools, electric aircraft and electric vehicles
WO2022168623A1 (en) * 2021-02-02 2022-08-11 株式会社村田製作所 Secondary battery, electronic device, and electric tool
WO2022209112A1 (en) 2021-03-31 2022-10-06 パナソニックＩｐマネジメント株式会社 Secondary battery electrode, secondary battery, and method for producing secondary battery electrode
WO2022209172A1 (en) 2021-03-31 2022-10-06 パナソニックＩｐマネジメント株式会社 Electrode for secondary battery, secondary battery, and method for manufacturing electrode for secondary battery

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