JP6365055B2 - Power storage device - Google Patents

Power storage device Download PDF

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JP6365055B2
JP6365055B2 JP2014148704A JP2014148704A JP6365055B2 JP 6365055 B2 JP6365055 B2 JP 6365055B2 JP 2014148704 A JP2014148704 A JP 2014148704A JP 2014148704 A JP2014148704 A JP 2014148704A JP 6365055 B2 JP6365055 B2 JP 6365055B2
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positive electrode
separator
welded
electrode
welding
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JP2016024969A (en
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泰有 秋山
泰有 秋山
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Toyota Industries Corp
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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

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  • Secondary Cells (AREA)
  • Electric Double-Layer Capacitors Or The Like (AREA)
  • Cell Separators (AREA)

Description

本発明は、蓄電装置に係り、詳しくは正極タブがセパレータから突出する状態でセパレータに包まれた正極と、負極とが交互に積層された積層型の電極組立体を備える蓄電装置に関する。 The present invention relates to a power storage equipment, and more particularly relates to a power storage equipment include a positive electrode wrapped in a separator in a state where the positive electrode tab protrudes from the separator, an electrode assembly of a laminated type in which a negative electrode are alternately laminated .

二次電池やキャパシタのような蓄電装置は再充電が可能であり、繰り返し使用することができるため電源として広く利用されている。例えば、ＥＶ（Electric Vehicle）やＰＨＶ（Plug-in Hybrid Vehicle）などの車両に搭載される蓄電装置としては、リチウムイオン二次電池や、ニッケル水素二次電池などがよく知られている。そして、蓄電装置は、金属箔に活物質を含有するスラリー状の活物質合剤が塗工されて形成された活物質層を有するシート状の正極及びシート状の負極が、間にセパレータが存在する状態で層をなすように積層あるいは巻回された電極組立体を備えている。   Power storage devices such as secondary batteries and capacitors are widely used as power sources because they can be recharged and can be used repeatedly. For example, as a power storage device mounted on a vehicle such as an EV (Electric Vehicle) or a PHV (Plug-in Hybrid Vehicle), a lithium ion secondary battery, a nickel hydride secondary battery, or the like is well known. The power storage device has a sheet-like positive electrode and a sheet-like negative electrode each having an active material layer formed by coating a metal foil with a slurry-like active material mixture containing an active material, with a separator in between The electrode assembly is stacked or wound so as to form a layer in the state of being.

積層型の電極組立体として、袋状のセパレータに収容された正極と、負極とが交互に積層された構成のものがある。図７（ａ）に示すように、正極４１は、タブ４１ａの一部が袋状のセパレータ４２から突出する状態でセパレータ４２内に収容され、セパレータ４２の溶着部４３は正極４１を囲むように形成されている。セパレータ４２にはイオンの通過を許容する微細孔（図示せず）が形成されており、正極の活物質層と対応する部分の微細孔が潰れると、その部分はイオンが通過できないため、正極の有効面積が小さくなる。そのため、溶着部４３は正極４１の周縁から距離をおいて形成される。また、セパレータ４２のタブ４１ａと対向する部分にも溶着部４３が形成されていない。そのため、正極４１は、セパレータ４２で包まれているが、セパレータ４２の中で正極４１のずれが発生する。   As a stacked electrode assembly, there is a configuration in which a positive electrode and a negative electrode housed in a bag-shaped separator are alternately stacked. As shown in FIG. 7A, the positive electrode 41 is accommodated in the separator 42 with a part of the tab 41 a protruding from the bag-like separator 42, and the welding portion 43 of the separator 42 surrounds the positive electrode 41. Is formed. The separator 42 is formed with micropores (not shown) that allow the passage of ions. When the micropores in a portion corresponding to the active material layer of the positive electrode are crushed, ions cannot pass through the portion. The effective area is reduced. Therefore, the welded portion 43 is formed at a distance from the periphery of the positive electrode 41. Further, the welded portion 43 is not formed on the portion of the separator 42 facing the tab 41a. Therefore, although the positive electrode 41 is wrapped with the separator 42, the positive electrode 41 is displaced in the separator 42.

また、図８に示すように、二つ折りにしたセパレータ４５の側辺４５ｂ，４５ｂの２辺を溶着して袋状に成形して正極４６とセパレータ４５とを一体化するとともに、当該一体化物の表裏両面において、正極タブ４７の取付部を含む正極４６の上縁部４６ａに対面している部分のセパレータ４５を溶融したものが提案されている（特許文献１参照）。正極タブ４７の取付部を含む正極４６の上縁部４６ａに対面している部分のセパレータ４５を溶融するのは、正極４６の上縁部４６ａからの活物質の脱落を抑制して内部短絡を防止するためである。   Further, as shown in FIG. 8, the two sides of the separator 45 that is folded in half are welded and formed into a bag shape to integrate the positive electrode 46 and the separator 45, and On both the front and back surfaces, a melted portion of the separator 45 facing the upper edge portion 46a of the positive electrode 46 including the attachment portion of the positive electrode tab 47 has been proposed (see Patent Document 1). The portion of the separator 45 facing the upper edge portion 46a of the positive electrode 46 including the attachment portion of the positive electrode tab 47 is melted by suppressing the falling off of the active material from the upper edge portion 46a of the positive electrode 46, thereby causing an internal short circuit. This is to prevent it.

特開平１１−４０１４７号公報Japanese Patent Laid-Open No. 11-40147

特許文献１には、正極の上縁部からの活物質の脱落を抑制して内部短絡を防止するために、正極の上縁部と対面する部分のセパレータが溶融されて被膜化しているため、セパレータ内で正極がずれ難くなる。しかし、特許文献１の場合も、セパレータ同士を溶着する部分は、電極から離れた位置に形成されている。これは、正極にかかった部分のセパレータを溶着すると、セパレータの微細孔が潰れるためその分、活物質層を有効に利用することができなくなることを回避するためである。一方、セパレータの溶着部は、強度上かつ製造上、一定以上の幅が必要である。そのため、セパレータ同士を溶着する構成では、図７（ｂ）に示すように、正極４１と溶着部４３との間に隙間４４を設け、その外側に溶着部４３が設けられる構造となる。その結果、電極組立体が同じ大きさの場合、隙間の分だけ有効電極部が減少することになる。   In Patent Document 1, in order to prevent the active material from dropping from the upper edge of the positive electrode and prevent an internal short circuit, the separator in the portion facing the upper edge of the positive electrode is melted to form a film. The positive electrode is difficult to shift in the separator. However, in the case of Patent Document 1, the portion where the separators are welded is formed at a position away from the electrodes. This is for avoiding that the active material layer cannot be effectively used correspondingly because the fine pores of the separator are crushed when the portion of the separator applied to the positive electrode is welded. On the other hand, the welded portion of the separator needs to have a certain width or more in terms of strength and manufacturing. Therefore, in the configuration in which the separators are welded to each other, as shown in FIG. 7B, a gap 44 is provided between the positive electrode 41 and the welded portion 43, and the welded portion 43 is provided outside thereof. As a result, when the electrode assembly is the same size, the effective electrode portion is reduced by the gap.

本発明は、前記の問題に鑑みてなされたものであって、その目的は、セパレータ内での正極のずれを防止するとともに、有効電極部の面積を大きくすることができる蓄電装置を提供することにある。
The present invention was made in view of the above problems, and its object is possible to prevent the deviation of the positive electrode in the separator, providing a power storage equipment capable of increasing the area of the effective electrode portion There is.

上記課題を解決する蓄電装置は、正極タブがセパレータから突出する状態でセパレータに包まれた正極と、負極とが交互に積層された積層型の電極組立体を備える蓄電装置であって、前記セパレータは、相対する一対のシートの縁部同士が溶着された第１の溶着部を有し、少なくとも一辺には前記第１の溶着部と連続した状態で前記正極の周縁部と溶着された第２の溶着部を有する。   A power storage device that solves the above problem is a power storage device including a stacked electrode assembly in which a positive electrode and a negative electrode are alternately stacked with a positive electrode tab protruding from the separator, the separator being the separator. Has a first welded portion in which edges of a pair of opposed sheets are welded to each other, and at least one side is a second welded to the peripheral edge of the positive electrode in a state of being continuous with the first welded portion. It has a welding part.

セパレータの強度を確保するため、溶着部は所定の幅が必要になる。セパレータは、少なくとも一辺に正極の周縁部と溶着された第２の溶着部を有するため、その部分ではセパレータの微細孔が潰れて正極の活物質層に無効な領域ができる。しかし、正極の周縁部に溶着された部分はセパレータのシート同士が溶着された第１の溶着部と連続しているため、正極の活物質層に生じる無効な領域は溶着部と重なる状態になる。セパレータの溶着部は、もともと有効電極部とはならない領域のため、セパレータが同じ大きさの場合、有効電極部と溶着部との間に隙間が無いこの構成では、隙間が無い分、結果として有効電極部の面積が大きくなる。したがって、セパレータ内での正極のずれを防止するとともに、有効電極部の面積を大きくすることができる。   In order to ensure the strength of the separator, the welded portion needs to have a predetermined width. Since the separator has a second welded portion welded to the peripheral edge of the positive electrode on at least one side, the fine pores of the separator are crushed at that portion, and an ineffective region is formed in the active material layer of the positive electrode. However, since the portion welded to the peripheral edge of the positive electrode is continuous with the first welded portion where the separator sheets are welded together, the ineffective region generated in the active material layer of the positive electrode overlaps the welded portion. . Since the welded part of the separator is an area that does not originally become an effective electrode part, when the separator is the same size, there is no gap between the effective electrode part and the welded part. The area of the electrode part increases. Accordingly, it is possible to prevent the positive electrode from shifting in the separator and to increase the area of the effective electrode portion.

前記負極は、前記セパレータの大きさ以上の大きさに形成されていることが好ましい。積層された状態において、負極とセパレータとのずれが発生した場合、負極とセパレータとを同じ大きさにしていると、正極と負極とが対向しない部分が生じる虞がある。しかし、負極をセパレータより大きく形成した場合、ずれが発生しても正極が負極と対向しない部分が生じることを抑制することができる。   It is preferable that the negative electrode is formed in a size larger than the size of the separator. When the negative electrode and the separator are displaced in the stacked state, if the negative electrode and the separator have the same size, a portion where the positive electrode and the negative electrode do not face each other may be generated. However, when the negative electrode is formed larger than the separator, it is possible to suppress the occurrence of a portion in which the positive electrode does not face the negative electrode even if a deviation occurs.

前記セパレータは、全周が前記正極の周縁部と連続して溶着されていることが好ましい。この場合、正極がセパレータ内でずれることが確実に防止される。
上記課題を解決する蓄電装置の製造方法は、正極タブがセパレータから突出する状態でセパレータに包まれた正極と、負極とが交互に積層された積層型の電極組立体を備える蓄電装置の製造方法であって、前記正極を前記セパレータを構成する一対のシートの間に配置した状態で前記一対のシートを溶着する溶着工程は、前記シート同士が溶着される第１の溶着部の溶着を、前記シートが前記正極に溶着される第２の溶着部の溶着と同時に行う。 It is preferable that the separator is continuously welded to the peripheral edge of the positive electrode. In this case, the positive electrode is reliably prevented from shifting in the separator.
A method of manufacturing a power storage device that solves the above problem includes a method of manufacturing a power storage device including a stacked electrode assembly in which a positive electrode and a negative electrode are alternately stacked in a state where a positive electrode tab protrudes from the separator. In the welding step of welding the pair of sheets in a state where the positive electrode is disposed between the pair of sheets constituting the separator, the welding of the first welding portion to which the sheets are welded is performed as described above. This is performed simultaneously with the welding of the second welded portion where the sheet is welded to the positive electrode.

正極を包むセパレータのシートの溶着部が、シート同士が溶着された第１の溶着部と、シートが正極に溶着された第２の溶着部とが連続するように形成する場合、溶着作業をシート同士を溶着する作業と、シートと正極とを溶着する作業との二回に分けて行うことも可能である。しかし、同時に行う方が、作業の手間が簡単になるとともに、第１の溶着部と第２の溶着部が同じ状態で連続するように溶着することができる。   When the welded portion of the separator sheet surrounding the positive electrode is formed so that the first welded portion where the sheets are welded to each other and the second welded portion where the sheet is welded to the positive electrode are continuous, the welding operation is performed. It is also possible to divide the work into two operations, that is, the operation of welding each other and the operation of welding the sheet and the positive electrode. However, it is possible to perform welding simultaneously so that the work is simplified and the first welded portion and the second welded portion are continuous in the same state.

本発明によれば、セパレータ内での正極のずれを防止するとともに、有効電極部の面積を大きくすることができる。   According to the present invention, it is possible to prevent the positive electrode from shifting in the separator and to increase the area of the effective electrode portion.

一実施形態の二次電池の模式断面図。The schematic cross section of the secondary battery of one Embodiment. 電極組立体の模式斜視図。The model perspective view of an electrode assembly. （ａ）はセパレータに包まれた正極の模式図、（ｂ）は溶着部セパレータ、正極の位置関係を示す模式断面図。(A) is a schematic diagram of the positive electrode wrapped in the separator, (b) is a schematic cross-sectional view showing the positional relationship between the welded portion separator and the positive electrode. 溶着工程を説明する模式斜視図。The model perspective view explaining a welding process. 溶着部が形成された状態の模式平面図。The schematic plan view of the state in which the welding part was formed. 別の実施形態を示す模式正面図。The schematic front view which shows another embodiment. （ａ）は従来技術におけるセパレータに包まれた正極の模式図、（ｂ）はその部分断面図。(A) is the schematic diagram of the positive electrode wrapped in the separator in a prior art, (b) is the fragmentary sectional view. 従来技術の正極が一体化されたセパレータの模式図。The schematic diagram of the separator with which the positive electrode of the prior art was integrated.

以下、本発明をリチウムイオン二次電池に具体化した一実施形態を図１〜図５にしたがって説明する。
図１に示すように、蓄電装置としての二次電池１０は、直方体状のケース１１内に、積層型の電極組立体１２が収容されている。ケース１１は、有底四角筒状の金属製（例えば、アルミニウム又はアルミニウム合金製）のケース本体１１ａと、ケース本体１１ａの開口部を塞ぐ蓋体１１ｂとで構成されている。なお、ケース１１内には図示しないが電解液も収容されている。二次電池１０は、リチウムイオン二次電池に具体化されている。 Hereinafter, an embodiment in which the present invention is embodied in a lithium ion secondary battery will be described with reference to FIGS.
As shown in FIG. 1, a secondary battery 10 as a power storage device includes a stacked electrode assembly 12 housed in a rectangular parallelepiped case 11. The case 11 includes a bottomed square cylindrical metal case body 11a (for example, aluminum or aluminum alloy) and a lid body 11b that closes the opening of the case body 11a. In addition, although not illustrated in the case 11, the electrolyte solution is also accommodated. The secondary battery 10 is embodied as a lithium ion secondary battery.

図２に示すように、電極組立体１２は、正極タブ１３ａがセパレータ１４から突出する状態でセパレータ１４に包まれた正極１３と、負極１５とが交互に積層された積層型の電極組立体である。   As shown in FIG. 2, the electrode assembly 12 is a stacked electrode assembly in which the positive electrode 13 and the negative electrode 15 that are wrapped in the separator 14 are alternately stacked with the positive electrode tab 13 a protruding from the separator 14. is there.

図２に示すように、正極１３は、集電体としての金属箔１６の両面に矩形状に形成された活物質層１３ｂを有し、活物質が塗布されていない活物質非塗布部１３ｃが活物質層１３ｂの上側に設けられている。正極タブ１３ａは活物質非塗布部１３ｃから突出形成された状態で、正極１３の左側上部に形成されている。   As shown in FIG. 2, the positive electrode 13 has an active material layer 13 b formed in a rectangular shape on both surfaces of a metal foil 16 as a current collector, and an active material non-applied portion 13 c that is not coated with an active material. It is provided on the upper side of the active material layer 13b. The positive electrode tab 13a is formed on the upper left side of the positive electrode 13 in a state of protruding from the active material non-application portion 13c.

負極１５は、集電体としての金属箔１６の両面に矩形状に形成された活物質層１５ｂを有し、活物質が塗布されていない活物質非塗布部１５ｃが活物質層１５ｂの上側に設けられている。負極タブ１５ａは活物質非塗布部１５ｃから突出形成された状態で、負極１５の右側上部に形成されている。負極１５は、セパレータ１４の大きさ以上の大きさに形成されている。   The negative electrode 15 has an active material layer 15b formed in a rectangular shape on both surfaces of a metal foil 16 as a current collector, and an active material non-applied portion 15c to which no active material is applied is located above the active material layer 15b. Is provided. The negative electrode tab 15a is formed on the upper right side of the negative electrode 15 in a state of protruding from the active material non-application portion 15c. The negative electrode 15 is formed in a size larger than the size of the separator 14.

二次電池１０がリチウムイオン二次電池の場合、正極１３用の金属箔１６はアルミニウム箔が好ましく、負極１５用の金属箔１６は銅箔が好ましい。
図１に示すように、蓋体１１ｂには正極端子１７及び負極端子１８が固定されている。正極端子１７及び負極端子１８は、雄ねじ部１７ａ，１８ａ及び鍔部１７ｂ，１８ｂを有し、蓋体１１ｂに形成された孔（図示せず）を、鍔部１７ｂ，１８ｂがケース１１の内側に位置する状態で貫通して蓋体１１ｂから突出する雄ねじ部１７ａ，１８ａに螺合するナット１９により、蓋体１１ｂに締め付け固定されている。正極端子１７及び負極端子１８は、複数の二次電池１０を電気的に接続するバスバー２０をボルト２１により締め付け固定可能に構成されている。なお、鍔部１７ｂ，１８ｂと蓋体１１ｂとの間及びナット１９と蓋体１１ｂとの間には図示しない電気的絶縁材製のシール部材が介装されている。 When the secondary battery 10 is a lithium ion secondary battery, the metal foil 16 for the positive electrode 13 is preferably an aluminum foil, and the metal foil 16 for the negative electrode 15 is preferably a copper foil.
As shown in FIG. 1, a positive terminal 17 and a negative terminal 18 are fixed to the lid 11b. The positive electrode terminal 17 and the negative electrode terminal 18 have male screw portions 17 a and 18 a and flange portions 17 b and 18 b, and holes (not shown) formed in the lid body 11 b, and the flange portions 17 b and 18 b are formed inside the case 11. It is fastened and fixed to the lid body 11b by a nut 19 that is threadedly engaged with the male threaded portions 17a and 18a that penetrate in a positioned state and protrude from the lid body 11b. The positive terminal 17 and the negative terminal 18 are configured so that a bus bar 20 that electrically connects the plurality of secondary batteries 10 can be fastened and fixed by bolts 21. A sealing member made of an electrically insulating material (not shown) is interposed between the flanges 17b and 18b and the lid body 11b and between the nut 19 and the lid body 11b.

正極端子１７は鍔部１７ｂに接合された導電部材２２を介して電極組立体１２の正極タブ１３ａに電気的に接続されている。負極端子１８は鍔部１８ｂに接合された導電部材２３を介して電極組立体１２の負極タブ１５ａに電気的に接続されている。   The positive electrode terminal 17 is electrically connected to the positive electrode tab 13a of the electrode assembly 12 through a conductive member 22 bonded to the flange portion 17b. The negative electrode terminal 18 is electrically connected to the negative electrode tab 15a of the electrode assembly 12 through a conductive member 23 bonded to the flange portion 18b.

図２及び図３（ｂ）に示すように、セパレータ１４は、相対する一対の樹脂製のシート１４ａの縁部同士が溶着され、かつ一部が正極１３の周縁部と連続して溶着されている。シート１４ａは、例えば、多孔性のポリプロピレン製である。図３（ａ）に示すように、この実施形態では、セパレータ１４は、２枚の樹脂製のシート１４ａが正極１３を挟んだ状態で、その全周が正極１３の周縁部と連続して溶着されている。   As shown in FIGS. 2 and 3 (b), the separator 14 has a pair of opposed resin sheets 14 a welded to each other, and a part of the separator 14 is welded continuously to the peripheral edge of the positive electrode 13. Yes. The sheet 14a is made of, for example, porous polypropylene. As shown in FIG. 3A, in this embodiment, the separator 14 is continuously welded with the peripheral edge of the positive electrode 13 with two resin sheets 14 a sandwiching the positive electrode 13. Has been.

図３（ａ），（ｂ）に示すように、セパレータ１４の溶着部３１は、セパレータ１４を構成する２枚のシート１４ａ同士が溶着された第１の溶着部３１ａと、シート１４ａと正極１３の周縁部とが溶着された第２の溶着部３１ｂとから成り、第１の溶着部３１ａと第２の溶着部３１ｂとが連続している。第１の溶着部３１ａは、図３（ａ）において破線で示す正極１３の外形線の外側の領域になる。また、第２の溶着部３１ｂは、図３（ａ）において二点鎖線で示す矩形の外側で、かつ破線で示す正極１３の外形線の内側の領域になる。   As shown in FIGS. 3A and 3B, the welded portion 31 of the separator 14 includes a first welded portion 31 a in which two sheets 14 a constituting the separator 14 are welded together, the sheet 14 a, and the positive electrode 13. And the second welded portion 31b welded to the peripheral edge portion, and the first welded portion 31a and the second welded portion 31b are continuous. The first welded portion 31a is a region outside the outline of the positive electrode 13 indicated by a broken line in FIG. Moreover, the 2nd welding part 31b becomes an area | region inside the external shape of the positive electrode 13 shown with the broken line outside shown by the dashed-two dotted line in Fig.3 (a).

図３（ｂ）では、金属箔１６、活物質層１３ｂ、シート１４ａを分かり易くするため、模式的に厚さを誇張して図示しているため、第１の溶着部３１ａと第２の溶着部３１ｂとの間に溶着されていない部分が有るように見えるが、１枚の正極１３の厚さは０．１ｍｍ程度であるため、実際は第１の溶着部３１ａと第２の溶着部３１ｂとが連続している。   In FIG. 3B, in order to make the metal foil 16, the active material layer 13b, and the sheet 14a easy to understand, the thickness is schematically exaggerated, so that the first welded portion 31a and the second welded portion are illustrated. Although it seems that there is a portion that is not welded to the portion 31b, since the thickness of one positive electrode 13 is about 0.1 mm, the first welded portion 31a and the second welded portion 31b are actually Is continuous.

二次電池１０の製造方法は、２枚のシート１４ａの間に正極１３を挟んだ状態で、シート１４ａ同士及び正極１３の周囲とシート１４ａとを溶着する溶着工程が従来と異なり、他の工程は従来の工程と基本的に同じため説明を省略する。   The manufacturing method of the secondary battery 10 is different from the conventional method in that the welding process of welding the sheets 14a to each other and the periphery of the positive electrode 13 and the sheet 14a in a state where the positive electrode 13 is sandwiched between the two sheets 14a. Since is basically the same as the conventional process, description thereof is omitted.

溶着工程では、図４に示すように、まず、２枚の帯状のシート１４ａの間に、複数の正極１３を所定間隔を置いて並べて配置し、正極１３をシート１４ａで挟み込む。
次に、図５に示すように、シート１４ａに挟まれた状態の正極１３の周縁部と、シート１４ａの周縁部とを溶着装置の溶着体で同時に押圧して溶着を行う。例えば、溶着を超音波ウェルダーで行う場合は、溶着体はホーンになる。そして、溶着体でセパレータ１４の四辺を順に押圧して溶着が行われる。溶着体は、２枚のシート１４ａのみが重なる部分と、正極１３とシート１４ａとが重なる部分とに跨った状態でシート１４ａ及び正極１３を同時に押圧するため、第１の溶着部３１ａ及び第２の溶着部３１ｂが同時に形成され、溶着部３１は第１の溶着部３１ａと第２の溶着部３１ｂとが連続する状態で形成される。 In the welding step, as shown in FIG. 4, first, a plurality of positive electrodes 13 are arranged at predetermined intervals between two strip-shaped sheets 14a, and the positive electrodes 13 are sandwiched between the sheets 14a.
Next, as shown in FIG. 5, welding is performed by simultaneously pressing the peripheral edge of the positive electrode 13 sandwiched between the sheets 14 a and the peripheral edge of the sheet 14 a with the welding body of the welding apparatus. For example, when welding is performed with an ultrasonic welder, the welded body becomes a horn. Then, welding is performed by sequentially pressing the four sides of the separator 14 with the welded body. Since the welded body presses the sheet 14a and the positive electrode 13 at the same time in a state of straddling the part where only the two sheets 14a overlap and the part where the positive electrode 13 and the sheet 14a overlap, the first welded part 31a and the second welded part The weld portion 31b is formed at the same time, and the weld portion 31 is formed in a state in which the first weld portion 31a and the second weld portion 31b are continuous.

次に前記のように構成された二次電池１０の作用を説明する。
セパレータ１４は、少なくとも一辺が正極１３の周縁部に溶着されるため、その部分ではセパレータ１４の微細孔が潰れて正極１３の活物質層１３ｂに無効な領域ができる。しかし、シート１４ａの正極１３の周縁部に溶着された部分は、セパレータ１４のシート１４ａ同士が溶着された部分と連続しているため、正極１３の活物質層１３ｂに生じる無効な領域は溶着部３１と重なる状態になる。そして、二次電池１０は、セパレータ１４を挟んで正極１３の活物質層１３ｂが形成された部分と、負極１５の活物質層１５ｂが形成された部分とが対向する部分の面積から、第２の溶着部３１ｂ、すなわちシート１４ａと正極１３の周縁部とが溶着されてセパレータ１４の微細孔が潰れた部分の面積を差し引いた面積が有効な電極部となる。正極１３の活物質層１３ｂの面積は負極１５の活物質層１５ｂの面積より小さいため、有効な電極部となる面積は、正極１３の活物質層１３ｂの面積から第２の溶着部３１ｂの面積を差し引いた値となる。この面積は、図３（ａ）において、二点鎖線で囲まれた部分の面積になる。 Next, the operation of the secondary battery 10 configured as described above will be described.
Since at least one side of the separator 14 is welded to the peripheral edge of the positive electrode 13, the fine holes of the separator 14 are crushed at that portion, and an ineffective region is formed in the active material layer 13 b of the positive electrode 13. However, the portion welded to the peripheral edge portion of the positive electrode 13 of the sheet 14a is continuous with the portion where the sheets 14a of the separator 14 are welded to each other. Therefore, an ineffective region generated in the active material layer 13b of the positive electrode 13 is a welded portion. It will be in the state which overlaps 31. Then, the secondary battery 10 has a second area from the area of the portion where the active material layer 13b of the positive electrode 13 and the portion of the negative electrode 15 where the active material layer 15b is formed face each other with the separator 14 in between. An effective electrode part is obtained by subtracting the area of the welded part 31b, that is, the sheet 14a and the peripheral part of the positive electrode 13 to which the fine holes of the separator 14 are crushed. Since the area of the active material layer 13b of the positive electrode 13 is smaller than the area of the active material layer 15b of the negative electrode 15, the area serving as an effective electrode portion is the area of the second welded portion 31b from the area of the active material layer 13b of the positive electrode 13. The value is obtained by subtracting. This area is an area of a portion surrounded by a two-dot chain line in FIG.

一方、従来技術の場合、図７（ａ），（ｂ）に示すように、セパレータ４２の溶着部４３は、正極４１と溶着部４３との間に隙間４４を設けた状態で、正極４１の外側に溶着部４３が設けられている。その結果、電極組立体１２が同じ大きさの場合、即ち、セパレータ４２の大きさが同じ場合、隙間４４の分だけ有効電極部が減少することになる。   On the other hand, in the case of the prior art, as shown in FIGS. 7A and 7B, the welded portion 43 of the separator 42 has a gap 44 provided between the positive electrode 41 and the welded portion 43. A welded portion 43 is provided on the outside. As a result, when the electrode assembly 12 is the same size, that is, when the size of the separator 42 is the same, the effective electrode portion is reduced by the gap 44.

そのため、この実施形態の二次電池１０は、同じ大きさの電極組立体１２を使用した場合、従来技術に比べて高密度化が可能になる。
この実施形態によれば、以下に示す効果を得ることができる。 Therefore, when the secondary battery 10 of this embodiment uses the electrode assembly 12 having the same size, it is possible to increase the density as compared with the prior art.
According to this embodiment, the following effects can be obtained.

（１）二次電池１０は、正極タブ１３ａがセパレータ１４から突出する状態でセパレータ１４に包まれた正極１３と、負極１５とが交互に積層された積層型の電極組立体１２を備える蓄電装置である。そして、セパレータ１４は、相対する一対のシート１４ａの縁部同士が溶着された第１の溶着部３１ａを有し、少なくとも一辺には第１の溶着部３１ａと連続した状態で正極１３の周縁部と溶着された第２の溶着部３１ｂを有する。   (1) The secondary battery 10 includes a stacked electrode assembly 12 in which the positive electrode 13 and the negative electrode 15 that are wrapped in the separator 14 with the positive electrode tab 13a protruding from the separator 14 are alternately stacked. It is. And the separator 14 has the 1st welding part 31a to which the edge part of a pair of opposing sheet | seat 14a was welded, and the peripheral part of the positive electrode 13 in the state which followed the 1st welding part 31a at least on one side. The second welded portion 31b is welded.

シート１４ａが正極１３の周縁部に溶着された第２の溶着部３１ｂは、セパレータ１４のシート１４ａ同士が溶着された第１の溶着部３１ａと連続しているため、正極１３の活物質層１３ｂに生じる無効な領域は溶着部３１と重なる状態になる。セパレータ１４の溶着部３１は、もともと有効電極部とはならない領域のため、セパレータ１４が同じ大きさの場合、有効電極部と溶着部３１との間に隙間が無いこの構成では、隙間が無い分、結果として有効電極部の面積が大きくなる。したがって、セパレータ１４内での正極１３のずれを防止するとともに、有効電極部の面積を大きくすることができる。   Since the second welded portion 31b in which the sheet 14a is welded to the peripheral portion of the positive electrode 13 is continuous with the first welded portion 31a in which the sheets 14a of the separator 14 are welded together, the active material layer 13b of the positive electrode 13 is provided. The invalid region generated in the region overlaps with the welded portion 31. Since the welded portion 31 of the separator 14 is an area that is not originally an effective electrode portion, when the separator 14 is the same size, there is no gap between the effective electrode portion and the welded portion 31 in this configuration. As a result, the effective electrode area increases. Accordingly, it is possible to prevent the positive electrode 13 from shifting in the separator 14 and to increase the area of the effective electrode portion.

（２）負極１５は、セパレータ１４の大きさ以上の大きさに形成されている。積層された状態において、負極１５とセパレータ１４とのずれが発生した場合、負極１５をセパレータ１４の大きさより小さくしていると、正極１３と負極１５とが対向しない部分が生じる虞がある。しかし、負極１５をセパレータ１４の大きさ以上の大きさに形成した場合、ずれが発生しても正極１３が負極１５と対向しない部分が生じることを抑制することができる。   (2) The negative electrode 15 is formed in a size larger than the size of the separator 14. When the negative electrode 15 and the separator 14 are misaligned in the stacked state, if the negative electrode 15 is made smaller than the size of the separator 14, a portion where the positive electrode 13 and the negative electrode 15 do not face each other may be generated. However, when the negative electrode 15 is formed in a size larger than the size of the separator 14, it is possible to suppress the occurrence of a portion where the positive electrode 13 does not face the negative electrode 15 even if a deviation occurs.

（３）セパレータ１４は、全周が正極１３の周縁部と連続して溶着されている。この構成によれば、正極１３がセパレータ１４内でずれることが確実に防止される。
（４）二次電池（蓄電装置）１０の製造方法は、正極タブ１３ａがセパレータ１４から突出する状態でセパレータ１４に包まれた正極１３と、負極１５とが交互に積層された積層型の電極組立体１２を備える蓄電装置の製造方法である。そして、正極１３を、セパレータ１４を構成する一対のシート１４ａの間に配置した状態で一対のシート１４ａを溶着する溶着工程は、一対のシート１４ａのうち正極１３に溶着される部分と連続する状態でシート１４ａ同士が溶着される第１の溶着部３１ａの溶着を、シート１４ａが正極１３に溶着される第２の溶着部３１ｂの溶着と同時に行う。正極１３を包むセパレータ１４のシート１４ａの溶着部３１が、シート１４ａ同士が溶着された第１の溶着部３１ａと、シート１４ａが正極１３に溶着された第２の溶着部３１ｂとが連続するように形成する場合、溶着作業をシート１４ａ同士を溶着する作業と、シート１４ａと正極１３とを溶着する作業との二回に分けて行うことも可能である。しかし、同時に行う方が、作業の手間が簡単になるとともに、第１の溶着部３１ａと第２の溶着部３１ｂが同じ状態で連続するように溶着することができる。 (3) The separator 14 is continuously welded to the peripheral edge portion of the positive electrode 13. According to this configuration, the positive electrode 13 is reliably prevented from shifting in the separator 14.
(4) The manufacturing method of the secondary battery (power storage device) 10 includes a stacked electrode in which the positive electrode 13 and the negative electrode 15 that are wrapped in the separator 14 are alternately stacked with the positive electrode tab 13 a protruding from the separator 14. This is a method for manufacturing a power storage device including the assembly 12. And the welding process which welds a pair of sheet | seat 14a in the state which has arrange | positioned between the pair of sheet | seat 14a which comprises the separator 14 in the state which continues the part welded to the positive electrode 13 among a pair of sheet | seat 14a. Thus, the welding of the first welded portion 31a where the sheets 14a are welded together is performed simultaneously with the welding of the second welded portion 31b where the sheet 14a is welded to the positive electrode 13. The welded portion 31 of the sheet 14 a of the separator 14 that encloses the positive electrode 13 is continuous with the first welded portion 31 a in which the sheets 14 a are welded together and the second welded portion 31 b in which the sheet 14 a is welded to the positive electrode 13. In the case of forming the sheet, the welding operation can be performed in two steps, that is, the operation of welding the sheets 14a to each other and the operation of welding the sheet 14a and the positive electrode 13 together. However, it is possible to perform welding so that the first welding part 31a and the second welding part 31b are continuous in the same state while the work is performed at the same time, and the work is simplified.

実施形態は前記に限定されるものではなく、例えば、次のように具体化してもよい。
○ セパレータ１４は、正極タブ１３ａがセパレータ１４から突出する状態で、相対する一対のシート１４ａの縁部同士が溶着され、かつ少なくとも一辺が正極１３の周縁部と連続して溶着されていればよく、全周が正極１３の周縁部と連続して溶着されている必要はない。例えば、図６に示すように、正極タブ１３ａの突出方向に延びる二辺（図６における左右の二辺）の溶着部３１は、第１の溶着部３１ａ及び第２の溶着部３１ｂで構成され、セパレータ１４の上下の二辺は第１の溶着部３１ａのみで構成してもよい。また、左右の二辺は第１の溶着部３１ａで構成し、上下の二辺を第１の溶着部３１ａ及び第２の溶着部３１ｂで構成してもよい。三辺を第１の溶着部３１ａ及び第２の溶着部３１ｂで構成し、残りの一辺を第１の溶着部３１ａのみで構成してもよい。 The embodiment is not limited to the above, and may be embodied as follows, for example.
○ Separator 14 may be formed by welding the edges of a pair of opposed sheets 14a with the positive electrode tab 13a protruding from the separator 14 and at least one side being continuously welded to the peripheral edge of the positive electrode 13. The entire circumference need not be continuously welded to the peripheral edge of the positive electrode 13. For example, as shown in FIG. 6, the welded portions 31 on two sides (the two sides on the left and right in FIG. 6) extending in the protruding direction of the positive electrode tab 13a are composed of a first welded portion 31a and a second welded portion 31b. The two upper and lower sides of the separator 14 may be constituted only by the first welded portion 31a. Alternatively, the left and right sides may be constituted by the first welded portion 31a, and the upper and lower sides may be constituted by the first welded portion 31a and the second welded portion 31b. Three sides may be configured by the first welded portion 31a and the second welded portion 31b, and the remaining one side may be configured by only the first welded portion 31a.

○ 正極１３及び負極１５は、必ずしも金属箔１６の両面に活物質層１３ｂ，１５ｂが形成された構成に限らず、金属箔１６の片面にのみ活物質層１３ｂ，１５ｂが形成された構成であってもよい。   The positive electrode 13 and the negative electrode 15 are not limited to the configuration in which the active material layers 13b and 15b are formed on both surfaces of the metal foil 16, but the active material layers 13b and 15b are formed only on one surface of the metal foil 16. May be.

○ 金属箔１６の両面に活物質層１３ｂ，１５ｂが形成された正極１３及び負極１５を使用する場合も、積層方向の両端に位置する正極１３及び負極１５に、金属箔１６の片面に活物質層１３ｂ，１５ｂが形成された正極１３及び負極１５を使用してもよい。この場合、不要な活物質層１３ｂ，１５ｂが存在しない分、活物質が無駄にならない。   ○ Even when using the positive electrode 13 and the negative electrode 15 in which the active material layers 13 b and 15 b are formed on both surfaces of the metal foil 16, the active material on one side of the metal foil 16 is applied to the positive electrode 13 and the negative electrode 15 positioned at both ends in the stacking direction. You may use the positive electrode 13 and the negative electrode 15 in which the layers 13b and 15b were formed. In this case, since the unnecessary active material layers 13b and 15b do not exist, the active material is not wasted.

○ 正極タブ１３ａ及び負極タブ１５ａは、金属箔１６の一部を利用して一体形成されたものに限らず、別に形成されたタブ用金属箔を活物質非塗布部１３ｃ，１５ｃに溶接で接合した構成としてもよい。   ○ The positive electrode tab 13a and the negative electrode tab 15a are not limited to those integrally formed by using a part of the metal foil 16, but separately formed tab metal foils are joined to the active material non-applied portions 13c and 15c by welding. It is good also as the structure which carried out.

○ 二次電池１０は、リチウムイオン二次電池に限らず、ニッケル水素二次電池やニッケルカドミウム二次電池等の他の二次電池であってもよい。
○ 蓄電装置は、二次電池１０に限らず、例えば、電気二重層キャパシタやリチウムイオンキャパシタ等のようなキャパシタであってもよい。 The secondary battery 10 is not limited to a lithium ion secondary battery, and may be another secondary battery such as a nickel hydrogen secondary battery or a nickel cadmium secondary battery.
The power storage device is not limited to the secondary battery 10 and may be a capacitor such as an electric double layer capacitor or a lithium ion capacitor.

以下の技術的思想（発明）は前記実施形態から把握できる。
（１）請求項１又は請求項２に記載された前記セパレータの溶着部は、前記一対のシート同士が溶着された第１の溶着部と、シートと正極の周縁部とが溶着された第２の溶着部とから成り、前記第１の溶着部と前記第２の溶着部とが連続している。 The following technical idea (invention) can be understood from the embodiment.
(1) A welding portion of the separator described in claim 1 or claim 2 is a first welding portion where the pair of sheets are welded to each other, and a second welding portion where the sheet and the peripheral edge portion of the positive electrode are welded. The first welded portion and the second welded portion are continuous.

１０…蓄電装置としての二次電池、１２…電極組立体、１３…正極、１３ａ…正極タブ、１４…セパレータ、１４ａ…シート、１５…負極、３１…溶着部、３１ａ…第１の溶着部、３１ｂ…第２の溶着部。   DESCRIPTION OF SYMBOLS 10 ... Secondary battery as an electrical storage device, 12 ... Electrode assembly, 13 ... Positive electrode, 13a ... Positive electrode tab, 14 ... Separator, 14a ... Sheet, 15 ... Negative electrode, 31 ... Welding part, 31a ... First welding part, 31b ... 2nd welding part.

Claims (1)

正極タブがセパレータから突出する状態でセパレータに包まれた正極と、負極とが交互に積層された積層型の電極組立体を備える蓄電装置であって、
前記セパレータは、相対する一対のシートの縁部同士が溶着された第１の溶着部を有し、少なくとも一辺には前記第１の溶着部と連続した状態で前記正極の周縁部と溶着された第２の溶着部を有し、
前記セパレータは、全周が前記正極の周縁部と連続して溶着されていることを特徴とする蓄電装置。 A power storage device including a stacked electrode assembly in which a positive electrode and a negative electrode are alternately stacked in a state where a positive electrode tab protrudes from a separator,
The separator has a first welded portion in which edges of a pair of opposed sheets are welded to each other, and is welded to the peripheral edge of the positive electrode in a state of being continuous with the first welded portion on at least one side. have a second welded portion,
The separator, power storage device all around is characterized that you have been welded continuously with the peripheral edge portion of the positive electrode.
JP2014148704A 2014-07-22 2014-07-22 Power storage device Expired - Fee Related JP6365055B2 (en)

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