JP7367742B2 - Energy storage element - Google Patents

Energy storage element Download PDF

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JP7367742B2
JP7367742B2 JP2021165039A JP2021165039A JP7367742B2 JP 7367742 B2 JP7367742 B2 JP 7367742B2 JP 2021165039 A JP2021165039 A JP 2021165039A JP 2021165039 A JP2021165039 A JP 2021165039A JP 7367742 B2 JP7367742 B2 JP 7367742B2
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tab
active material
electrode sheet
positive electrode
insulating layer
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JP2022023106A (en
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好浩 山本
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GS Yuasa International Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/10—Multiple hybrid or EDL capacitors, e.g. arrays or modules
    • H01G11/12—Stacked hybrid or EDL capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/54—Connection of several leads or tabs of plate-like electrode stacks, e.g. electrode pole straps or bridges
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/10—Primary casings, jackets or wrappings of a single cell or a single battery
    • H01M50/172—Arrangements of electric connectors penetrating the casing
    • H01M50/174—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells
    • H01M50/176—Arrangements of electric connectors penetrating the casing adapted for the shape of the cells for prismatic or rectangular cells
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/74—Terminals, e.g. extensions of current collectors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01G—CAPACITORS; CAPACITORS, RECTIFIERS, DETECTORS, SWITCHING DEVICES OR LIGHT-SENSITIVE DEVICES, OF THE ELECTROLYTIC TYPE
    • H01G11/00—Hybrid capacitors, i.e. capacitors having different positive and negative electrodes; Electric double-layer [EDL] capacitors; Processes for the manufacture thereof or of parts thereof
    • H01G11/74—Terminals, e.g. extensions of current collectors
    • H01G11/76—Terminals, e.g. extensions of current collectors specially adapted for integration in multiple or stacked hybrid or EDL capacitors
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/536—Electrode connections inside a battery casing characterised by the method of fixing the leads to the electrodes, e.g. by welding
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M50/00—Constructional details or processes of manufacture of the non-active parts of electrochemical cells other than fuel cells, e.g. hybrid cells
    • H01M50/50—Current conducting connections for cells or batteries
    • H01M50/531—Electrode connections inside a battery casing
    • H01M50/538—Connection of several leads or tabs of wound or folded electrode stacks
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0585—Construction or manufacture of accumulators having only flat construction elements, i.e. flat positive electrodes, flat negative electrodes and flat separators
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/058—Construction or manufacture
    • H01M10/0587—Construction or manufacture of accumulators having only wound construction elements, i.e. wound positive electrodes, wound negative electrodes and wound separators
    • 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

Description

本発明は、セパレータを介して積層される正極シートおよび負極シートを有する蓄電素子に関する。 The present invention relates to a power storage element having a positive electrode sheet and a negative electrode sheet laminated with a separator interposed therebetween.

リチウムイオン電池のような蓄電素子には、セパレータを介して交互に積層された正極シート及び負極シートを有する電極体が用いられることがある。一般に、正極シート及び負極シートは、金属箔の両面に活物質層が塗工されることで形成される。 BACKGROUND ART In a power storage device such as a lithium ion battery, an electrode body having positive electrode sheets and negative electrode sheets alternately stacked with separators interposed therebetween may be used. Generally, a positive electrode sheet and a negative electrode sheet are formed by coating active material layers on both sides of metal foil.

特許文献１に開示されているように、蓄電素子の正極シート及び負極シートには、該シートの幅方向の一方側における直線状の縁部から幅方向の外側に突出したタブが設けられることがある。タブの少なくとも一部は、活物質層が形成されていない活物質非形成部とされ、該活物質非形成部は、集電体を介して外部端子に電気的に接続される。 As disclosed in Patent Document 1, the positive electrode sheet and the negative electrode sheet of a power storage element may be provided with a tab protruding outward in the width direction from a linear edge on one side in the width direction of the sheet. be. At least a portion of the tab is an active material non-forming portion where no active material layer is formed, and the active material non-forming portion is electrically connected to an external terminal via a current collector.

この種の蓄電素子において、正極シートには、タブだけでなく、該タブ側の縁部に沿った部分にも活物質非形成部が形成されることがある。また、このように正極シートの縁部に沿って形成された活物質非形成部は、セパレータを介して負極シートの活物質層に対向配置されることがある。 In this type of power storage element, the positive electrode sheet may have an active material-free portion formed not only in the tab but also in a portion along the edge on the tab side. Further, the active material-free portion formed along the edge of the positive electrode sheet may be disposed opposite to the active material layer of the negative electrode sheet with a separator interposed therebetween.

特許第５３５４０４２号公報Patent No. 5354042

しかしながら、上記のように正極シートのタブ側の縁部に沿って形成された活物質非形成部がセパレータを介して負極活物質層に対向配置された蓄電素子では、セパレータの位置ずれ、収縮又は破損のような何らかの原因によって、正極活物質非形成部と負極活物質層が直接対向する状態になった場合に、これらの間で短絡が生じる可能性がある。 However, in a power storage element in which the active material-free portion formed along the edge of the tab side of the positive electrode sheet is disposed opposite to the negative electrode active material layer with a separator in between, the separator may be misaligned, shrink, or If the positive electrode active material non-forming portion and the negative electrode active material layer come into a state of directly opposing each other due to some cause such as damage, a short circuit may occur between them.

そこで、本発明は、電極シートのタブ側の縁部に沿って活物質非形成部が設けられた蓄電素子において、前記活物質非形成部における短絡の発生を抑制することを目的とする。 SUMMARY OF THE INVENTION Therefore, an object of the present invention is to suppress the occurrence of short circuits in the active material-free portion in a power storage element in which the active material-free portion is provided along the edge of the electrode sheet on the tab side.

本発明に係る蓄電素子は、第１電極シートと、セパレータを介して前記第１電極シートに積層され、前記第１電極シートとは異なる極性を有する第２電極シートと、を備えた蓄電素子であって、前記第１電極シートは、第１方向に延びる縁部、及び、該縁部から前記第１方向に交差する第２方向に突出した第１タブを有する金属箔と、前記金属箔の表面に形成された活物質層と、前記金属箔の表面に形成された絶縁層と、を備え、前記第２電極シートは、前記第１方向に延びる縁部、及び、該縁部から前記第２方向に延びる第２タブを有し、前記第１タブと前記第２タブは、前記第２方向の同じ側に突出しており、前記金属箔における前記縁部に沿う部分及び前記第１タブは、前記活物質層が形成されていない活物質非形成部とされ、前記絶縁層は、前記活物質非形成部における前記第１タブの基部を含む領域に設けられ、前記第１タブは、前記基部においてアールが付けられており、前記絶縁層は、前記第１タブの前記アールを含む領域に形成されていることを特徴とする。または、本発明に係る蓄電素子は、電極体を備えた蓄電素子であって、前記電極体は、第１電極シートと、前記第１電極シートとは異なる極性を有する第２電極シートと、を有し、前記第１電極シートは、金属箔と、前記金属箔に設けられた活物質層と、前記金属箔に設けられた絶縁層と、を備え、前記金属箔は、前記活物質層が設けられていない活物質非形成部を有し、前記活物質非形成部は、前記金属箔の縁部に沿って延びる第１活物質非形成部と、前記第１活物質非形成部から突出した第１タブと、を有し、前記絶縁層は、前記活物質非形成部における前記第１タブの基部を含む領域に設けられ、前記第２電極シートは、縁部、及び、該縁部から突出した第２タブを有し、前記第１タブと前記第２タブは、前記電極体の同一端面部から突出しており、前記第１タブは、前記基部においてアールが付けられており、前記絶縁層は、前記アールに沿って形成されていることを特徴とする。 The electricity storage element according to the present invention includes a first electrode sheet and a second electrode sheet that is laminated on the first electrode sheet with a separator interposed therebetween and has a polarity different from that of the first electrode sheet. The first electrode sheet includes a metal foil having an edge extending in a first direction and a first tab protruding from the edge in a second direction intersecting the first direction; The second electrode sheet includes an active material layer formed on the surface and an insulating layer formed on the surface of the metal foil, and the second electrode sheet has an edge extending in the first direction, and a It has a second tab extending in two directions, the first tab and the second tab protrude on the same side in the second direction, and a portion of the metal foil along the edge and the first tab are , an active material non-forming part where the active material layer is not formed, the insulating layer is provided in a region including the base of the first tab in the active material non-forming part, and the first tab is A radius is provided at the base, and the insulating layer is formed in a region of the first tab that includes the radius. Alternatively, the electricity storage element according to the present invention is an electricity storage element including an electrode body, and the electrode body includes a first electrode sheet and a second electrode sheet having a polarity different from that of the first electrode sheet. The first electrode sheet includes a metal foil, an active material layer provided on the metal foil, and an insulating layer provided on the metal foil; a first active material non-formed portion extending along an edge of the metal foil and a first active material non-formed portion protruding from the first active material non-formed portion; the insulating layer is provided in a region including the base of the first tab in the active material non-forming part, and the second electrode sheet is provided at an edge and at the edge. a second tab protruding from the electrode body; the first tab and the second tab protrude from the same end face portion of the electrode body; the first tab is rounded at the base; The insulating layer is characterized in that it is formed along the radius.

これにより、セパレータの位置ずれ、収縮又は破損等によって第１電極シートが第２電極シートに直接対向する状態になった場合でも、第１電極シートの活物質非形成部と第２電極シートとの間に絶縁層が介在することで、第１電極シートの活物質非形成部における短絡の発生を抑制できる。 As a result, even if the first electrode sheet directly faces the second electrode sheet due to misalignment, shrinkage, or damage of the separator, the active material non-formed portion of the first electrode sheet and the second electrode sheet By interposing the insulating layer therebetween, it is possible to suppress the occurrence of a short circuit in the active material-free portion of the first electrode sheet.

本発明において、前記絶縁層は、前記活物質非形成部における前記第１タブの基部を含む領域に設けられることが好ましい。これにより、第１タブの基部における短絡の発生を抑制しつつ、該基部を絶縁層によって補強することができる。 In the present invention, it is preferable that the insulating layer is provided in a region including a base of the first tab in the active material non-forming part. This makes it possible to suppress the occurrence of short circuits at the base of the first tab while reinforcing the base with the insulating layer.

本発明において、前記第１タブは、前記基部においてアールが付けられていることが好ましい。これにより、第１タブの基部にかかる応力を分散させて、第１タブの強度を向上させることができる。 In the present invention, it is preferable that the first tab is rounded at the base. Thereby, the stress applied to the base of the first tab can be dispersed, and the strength of the first tab can be improved.

本発明に係る蓄電素子が、前記第１電極シートを外部端子に電気的に接続させる集電体を更に備える場合、前記第１タブは、折り曲げられた状態で前記集電体に接続されてもよい。この場合、折り曲げによって応力が集中する第１タブの基部が絶縁層によって補強されていることで、第１タブの剛性、耐久性の向上を図ることができる。 When the electricity storage element according to the present invention further includes a current collector that electrically connects the first electrode sheet to an external terminal, the first tab may be connected to the current collector in a bent state. good. In this case, the base of the first tab, where stress is concentrated due to bending, is reinforced by the insulating layer, thereby improving the rigidity and durability of the first tab.

本発明において、前記絶縁層における前記第１タブの表面に形成された部分は、前記第２方向において前記セパレータの縁部よりも突出していることが好ましい。これにより、セパレータの位置ずれ、収縮又は破損等によって第１タブがセパレータを介することなく第２電極シートに対向する状態になった場合でも、第１タブの金属箔と第２電極シートとの間に絶縁層が介在することで、第１タブにおける短絡の発生を抑制できる。 In the present invention, it is preferable that a portion of the insulating layer formed on the surface of the first tab protrudes from an edge of the separator in the second direction. As a result, even if the first tab faces the second electrode sheet without intervening the separator due to misalignment, shrinkage, or damage of the separator, there is a gap between the metal foil of the first tab and the second electrode sheet. By interposing the insulating layer in the first tab, it is possible to suppress the occurrence of a short circuit in the first tab.

本発明では、前記活物質非形成部において、前記金属箔の端面にも前記絶縁層が形成されていることが好ましい。これにより、第１電極シートの活物質非形成部における短絡の発生をより効果的に抑制できる。また、第１電極シートの前記縁部の端面が絶縁層で被覆されていることにより、この縁部の端面での短絡の抑制を図りつつ、第１電極シートの縁部よりも第２方向の外側に位置するセパレータの縁部に対して、第１電極シートの縁部を近づけて配置しやすくなる。そのため、第１電極シートを第２方向に拡大することができ、これにより、電池容量の増大を図ることができる。 In the present invention, it is preferable that the insulating layer is also formed on the end face of the metal foil in the active material non-forming part. This makes it possible to more effectively suppress the occurrence of short circuits in the active material non-forming portions of the first electrode sheet. Furthermore, since the end surface of the edge of the first electrode sheet is coated with an insulating layer, short circuits can be suppressed at the end surface of the edge, and the distance in the second direction from the edge of the first electrode sheet can be suppressed. This makes it easier to arrange the edge of the first electrode sheet close to the edge of the separator located on the outside. Therefore, the first electrode sheet can be expanded in the second direction, thereby increasing the battery capacity.

本発明において、前記第２電極シートが、前記第１方向に直線状に延びる縁部、及び、該縁部から前記第２方向に延びる第２タブを有する場合、前記第１タブと前記第２タブは、前記第２方向の同じ側に突出すると共に、前記第１方向に間隔を空けて配置されてもよい。この場合、この種の蓄電素子において上述の効果を得ることができる。 In the present invention, when the second electrode sheet has an edge extending linearly in the first direction and a second tab extending from the edge in the second direction, the first tab and the second The tabs may protrude on the same side in the second direction and be spaced apart in the first direction. In this case, the above-mentioned effects can be obtained in this type of power storage element.

本発明において、前記第１電極シートが、前記第１方向に間隔を空けて配置された複数の前記第１タブを備え、前記第１電極シートと前記第２電極シートが、前記セパレータを介して相互に重ねられながら前記第２方向に平行な軸周りに巻回されることで、巻回体を形成している場合、前記巻回体は、前記複数の第１タブを積層してなる第１タブ束を備えてもよい。この場合、第１タブの基部の剛性が絶縁層によって高められていることにより、第１電極シートを巻回する際に、該第１電極シートの厚み方向に反るような第１タブの撓みが抑制される。そのため、第１電極シートを巻回して複数の第１タブを重ねるときに、第１タブ同士が引っ掛かり難くなり、これにより、各第１タブの折れが抑制される。 In the present invention, the first electrode sheet includes a plurality of the first tabs arranged at intervals in the first direction, and the first electrode sheet and the second electrode sheet are connected to each other through the separator. When a wound body is formed by being wound around an axis parallel to the second direction while being overlapped with each other, the wound body is formed by laminating the plurality of first tabs. One tab bundle may be provided. In this case, since the rigidity of the base of the first tab is increased by the insulating layer, when the first electrode sheet is wound, the first tab is warped in the thickness direction of the first electrode sheet. is suppressed. Therefore, when the first electrode sheet is wound to overlap a plurality of first tabs, the first tabs are less likely to catch each other, thereby suppressing the bending of each first tab.

本発明において、前記巻回体が、前記軸の延びる方向から見て相互に平行な直線状に延びる一対のフラット部と、該一対のフラット部間を繋ぐ一対の湾曲部とを備える場合、前記第１タブ束は、前記フラット部に設けられてもよい。この場合、この種の蓄電素子において上述の効果を得ることができる。 In the present invention, when the wound body includes a pair of flat portions extending linearly parallel to each other when viewed from the direction in which the shaft extends, and a pair of curved portions connecting the pair of flat portions, The first tab bundle may be provided on the flat portion. In this case, the above-mentioned effects can be obtained in this type of power storage element.

本発明に係る蓄電素子が、複数の前記第１電極シートと複数の前記第２電極シートが前記セパレータを介して交互に積層されてなる積層体を備える場合、前記積層体は、前記複数の第１電極シートのそれぞれに設けられた前記第１タブを積層してなる第１タブ束を備えてもよい。この場合、この種の蓄電素子において上述の効果を得ることができる。 When the electricity storage element according to the present invention includes a laminate in which a plurality of first electrode sheets and a plurality of second electrode sheets are alternately laminated with the separator interposed therebetween, the laminate includes A first tab bundle may be provided in which the first tabs provided on each electrode sheet are laminated. In this case, the above-mentioned effects can be obtained in this type of power storage element.

本発明によれば、セパレータの位置ずれ、収縮又は破損等によって第１電極シートが第２電極シートに直接対向する状態になった場合でも、第１電極シートの活物質非形成部と第２電極シートとの間に絶縁層が介在することで、第１電極シートの活物質非形成部における短絡の発生を抑制できる。 According to the present invention, even if the first electrode sheet directly faces the second electrode sheet due to misalignment, shrinkage, or damage of the separator, the active material-free portion of the first electrode sheet and the second electrode By interposing the insulating layer between the first electrode sheet and the first electrode sheet, it is possible to suppress the occurrence of a short circuit in the active material-free portion of the first electrode sheet.

本発明の実施形態に係る蓄電素子を示す斜視図である。FIG. 1 is a perspective view showing a power storage element according to an embodiment of the present invention. 図１のＡ－Ａ線で破断して蓄電素子の内部を示す一部破断斜視図である。FIG. 2 is a partially cutaway perspective view taken along line AA in FIG. 1 and showing the inside of the power storage element. 図１に示す蓄電素子の電極体の斜視図である。FIG. 2 is a perspective view of an electrode body of the electricity storage element shown in FIG. 1. FIG. 図３に示す電極体の展開図である。4 is a developed view of the electrode body shown in FIG. 3. FIG. 正極シートの正極タブ及びその周辺部を示す図４の拡大図である。FIG. 5 is an enlarged view of FIG. 4 showing the positive electrode tab of the positive electrode sheet and its surrounding area. 正極シートの絶縁層の第１絶縁部及びその周辺部を正極シートの長手方向から見た図５のＢ－Ｂ線断面図である。FIG. 6 is a cross-sectional view taken along the line BB in FIG. 5 of the first insulating portion of the insulating layer of the positive electrode sheet and its peripheral portion as seen from the longitudinal direction of the positive electrode sheet. 正極シートの絶縁層の第２絶縁部及びその周辺部を正極シートの長手方向から見た図５のＣ－Ｃ線断面図である。FIG. 6 is a cross-sectional view taken along the line CC in FIG. 5 of the second insulating portion of the insulating layer of the positive electrode sheet and its peripheral portion as seen from the longitudinal direction of the positive electrode sheet. 正極シートの絶縁層の第２絶縁部及びその周辺部を正極タブの突出方向から見た図５のＤ－Ｄ線断面図である。FIG. 6 is a cross-sectional view taken along the line DD in FIG. 5 of the second insulating portion of the insulating layer of the positive electrode sheet and its surrounding area as viewed from the direction in which the positive electrode tab protrudes. 本発明の別の実施形態に係る蓄電素子の電極体を模式的に示す分解斜視図である。FIG. 7 is an exploded perspective view schematically showing an electrode body of a power storage element according to another embodiment of the present invention.

以下、添付図面を参照して本発明の実施形態を説明する。なお、本願明細書において方向を示すために使用される「上」及び「下」を含む用語及びこれらに関連する方向を示す用語は、添付図面に図示された蓄電素子の姿勢における方向を示すものであり、必ずしも実際の使用状態における方向と一致するものでない。 Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that terms including "upper" and "lower" used to indicate directions in the specification of this application and terms indicating directions related thereto indicate the directions in the orientation of the energy storage element illustrated in the attached drawings. This does not necessarily correspond to the direction in actual use.

図１は、本発明の実施形態に係る蓄電素子１を示している。蓄電素子１は、例えばリチウムイオン電池等の非水電解質二次電池である。ただし、本発明は、リチウムイオン電池以外にも、キャパシタを含む種々の蓄電素子に適用できる。 FIG. 1 shows a power storage element 1 according to an embodiment of the present invention. The power storage element 1 is, for example, a nonaqueous electrolyte secondary battery such as a lithium ion battery. However, the present invention can be applied to various power storage elements including capacitors in addition to lithium ion batteries.

図１に示すように、蓄電素子１は、例えば略直方体のケース２を有する。ケース２は、上面開口部を有するケース本体３と、ケース本体３の上面開口部を塞ぐ蓋体４とを有する。 As shown in FIG. 1, the power storage element 1 has a case 2 that is, for example, a substantially rectangular parallelepiped. The case 2 includes a case body 3 having an upper opening, and a lid 4 that closes the upper opening of the case body 3.

ケース本体３の材料には、例えばアルミニウム又はアルミニウム合金等の金属が用いられる。なお、ケース本体３の表面は、例えば樹脂からなる絶縁層（図示せず）で全体的に覆われるようにしてもよい。 The material of the case body 3 is, for example, metal such as aluminum or aluminum alloy. Note that the surface of the case body 3 may be entirely covered with an insulating layer (not shown) made of resin, for example.

蓋体４は例えば矩形の金属板である。蓋体４は、ケース本体３の開口縁部に溶接されている。蓋体４の表面には、正極の外部端子１１と負極の外部端子１２が固定されている。 The lid body 4 is, for example, a rectangular metal plate. The lid body 4 is welded to the opening edge of the case body 3. A positive external terminal 11 and a negative external terminal 12 are fixed to the surface of the lid 4.

各外部端子１１，１２は、蓋体４の上面に上ガスケット１３を介して例えばかしめによって固定されている。外部端子１１，１２の材料には、例えば、アルミニウム、銅、ニッケル等の金属が用いられる。 Each external terminal 11, 12 is fixed to the upper surface of the lid 4 via an upper gasket 13, for example, by caulking. For example, metals such as aluminum, copper, and nickel are used as the material for the external terminals 11 and 12.

また、蓋体４には、ケース本体３内で発生したガスをケース２の外側へ排出するためのガス排出弁８と、注液口（図示せず）が設けられている。注液口は、注液栓１０にて閉鎖されている。 Further, the lid body 4 is provided with a gas discharge valve 8 for discharging gas generated within the case body 3 to the outside of the case 2, and a liquid injection port (not shown). The liquid injection port is closed with a liquid injection stopper 10.

図２に示すように、ケース２には、少なくとも１つの電極体２０（特許請求の範囲の「巻回体」に相当）と、電極体２０を正極及び負極の外部端子１１，１２に電気的に接続する集電体１５と、電解液（図示せず）とが収容される。 As shown in FIG. 2, the case 2 includes at least one electrode body 20 (corresponding to the "wound body" in the claims), and the electrode body 20 is electrically connected to the positive and negative external terminals 11 and 12. A current collector 15 connected to the current collector 15 and an electrolytic solution (not shown) are accommodated therein.

図２に図示された集電体１５は、正極の外部端子１１に接続される正極集電体であり、図２を参照する以下の説明は、正極集電体１５の構成について行われ、負極の外部端子１２に接続される負極集電体の図示及び説明は省略される。 The current collector 15 illustrated in FIG. 2 is a positive electrode current collector connected to the external terminal 11 of the positive electrode, and the following explanation with reference to FIG. The illustration and description of the negative electrode current collector connected to the external terminal 12 will be omitted.

なお、負極集電体は、以下に説明される正極集電体１５と同様に構成されているが、正極集電体１５とは異なる構成を有してもよい。また、正極集電体１５及び負極集電体は互いに異なる材料で構成されてもよい。具体的に、正極集電体１５の材料には、例えば、アルミニウム等の金属が用いられ、負極集電体の材料には、例えば、銅等の金属が用いられる。 Note that the negative electrode current collector has the same configuration as the positive electrode current collector 15 described below, but may have a different configuration from the positive electrode current collector 15. Furthermore, the positive electrode current collector 15 and the negative electrode current collector may be made of different materials. Specifically, the material of the positive electrode current collector 15 is, for example, a metal such as aluminum, and the material of the negative electrode current collector is, for example, a metal such as copper.

集電体１５は、蓋体４の下面に下ガスケット１４を介して例えばかしめによって固定されている。集電体１５は、例えば、蓋体４に固定された第１平板部１５ａと、該第１平板部１５ａの縁部から湾曲しながら下方へ延びる連絡部１５ｂと、該連絡部１５ｂを介して第１平板部１５ａに連なり、該第１平板部１５ａの下方に対向配置される第２平板部１５ｃとを備えている。 The current collector 15 is fixed to the lower surface of the lid 4 via the lower gasket 14, for example, by caulking. The current collector 15 includes, for example, a first flat plate part 15a fixed to the lid 4, a connecting part 15b extending downward while being curved from the edge of the first flat plate part 15a, and a connecting part 15b extending downward through the connecting part 15b. It is provided with a second flat plate part 15c that is continuous with the first flat plate part 15a and is arranged oppositely below the first flat plate part 15a.

第１平板部１５ａは、例えば外部端子１１から下方に延びるリベット部（図示せず）を介して、外部端子１１に電気的に接続されている。第２平板部１５ｃの下面には、電極体２０に設けられた後述のタブ３５が例えば超音波溶接により接合されており、これにより、電極体２０に電気的に接続されている。 The first flat plate portion 15a is electrically connected to the external terminal 11 via, for example, a rivet portion (not shown) extending downward from the external terminal 11. A tab 35, which will be described later and provided on the electrode body 20, is joined to the lower surface of the second flat plate portion 15c by, for example, ultrasonic welding, thereby electrically connecting to the electrode body 20.

図３及び図４を併せて参照すると、電極体２０は、いずれも一定幅の長尺な帯状である正極シート（特許請求の範囲の「第１電極シート」に相当）２１、負極シート２２（特許請求の範囲の「第２電極シート」に相当）及び微多孔性樹脂シートからなる２枚のセパレータ２３，２３を重ね合わせて、概ね高平率の長円状に巻回したものである。正極シート２１の一つの層と、それに隣接する負極シート２２の一つの層との間には、２枚のセパレータ２３，２３のうちのいずれか一方が介在している。セパレータ２３，２３は、正極シート２１及び負極シート２２よりも長尺である。これにより、電極体２０の最外層は、いずれか一方のセパレータ２３で構成されている。 3 and 4, the electrode body 20 includes a positive electrode sheet 21 (corresponding to the "first electrode sheet" in the claims) 21, a negative electrode sheet 22 (corresponding to the "first electrode sheet" in the claims), and a negative electrode sheet 22 (corresponding to the "first electrode sheet" in the claims). Two separators 23, 23 made of a microporous resin sheet (corresponding to the "second electrode sheet" in the claims) and a microporous resin sheet are overlapped and wound into an oval shape with a generally high flatness ratio. One of the two separators 23, 23 is interposed between one layer of the positive electrode sheet 21 and one layer of the negative electrode sheet 22 adjacent thereto. The separators 23 and 23 are longer than the positive electrode sheet 21 and the negative electrode sheet 22. Thereby, the outermost layer of the electrode body 20 is made up of one of the separators 23.

正極シート２１、負極シート２２及び２枚のセパレータ２３，２３の巻回の軸線（巻回軸）は、図３において符号Ｘで概念的に示されている。電極体２０は、巻回軸Ｘが概ね、図１に示すケース本体３の底壁部と上面開口部が対向する方向（図１における上下方向）に延びる姿勢で、ケース本体３内に収容されている。 The winding axes (winding axes) of the positive electrode sheet 21, the negative electrode sheet 22, and the two separators 23, 23 are conceptually indicated by the symbol X in FIG. The electrode body 20 is housed in the case body 3 with the winding axis X generally extending in the direction in which the bottom wall and the top opening of the case body 3 shown in FIG. 1 face each other (vertical direction in FIG. 1). ing.

図３に示すように、巻回軸Ｘの延びる方向における電極体２０の各端部は、正極シート２１、負極シート２２及びセパレータ２３，２３の幅方向（短手方向）の端部が配置された端面部２０ａ，２０ｂとなっている。電極体２０は、巻回軸Ｘを挟んで対向配置され、巻回軸Ｘの延びる方向から見て相互に平行な直線状に延びる一対のフラット部２０ｃ，２０ｃと、巻回軸Ｘの延びる方向から見て半円状に湾曲するように延びて一対のフラット部２０ｃ，２０ｃ間を繋ぐ一対の湾曲部２０ｄ，２０ｄとを有する。 As shown in FIG. 3, each end of the electrode body 20 in the extending direction of the winding axis The end face portions 20a and 20b are formed with a cylindrical shape. The electrode body 20 includes a pair of flat portions 20c, 20c, which are arranged opposite to each other with the winding axis X in between, and extend in a straight line parallel to each other when viewed from the direction in which the winding axis X extends; It has a pair of curved portions 20d, 20d extending in a semicircular shape when viewed from above, and connecting the pair of flat portions 20c, 20c.

なお、フラット部２０ｃは、設計上において直線状に延びる部分である。実際にケース２に電極体２０が収容された状態において、フラット部２０ｃは、完全な直線状に配置されるとは限らず、全体的には直線に近い形状となるように撓んだ状態で配置されることもある。 Note that the flat portion 20c is a portion that extends linearly in design. When the electrode body 20 is actually housed in the case 2, the flat portion 20c is not necessarily arranged in a perfect straight line, but is bent so as to have an overall shape close to a straight line. Sometimes it is placed.

図３及び図４に示すように、正極シート２１は、帯状の正極金属箔２４と、この正極金属箔２４の両面に形成された正極活物質層２５とを備える。正極金属箔２４の幅方向（短手方向）両側の縁部は、正極金属箔２４の長手方向に沿って直線状に延びるように形成されている。正極金属箔２４の幅方向の一方側（図３及び図４において下側）においては、正極金属箔２４の縁部まで正極活物質層２５が設けられている。正極金属箔２４の幅方向の他方側（図３及び図４において上側）の縁部には、正極活物質層２５を設けずに、正極金属箔２４を露出させた第１活物質非形成部３４が設けられている。正極金属箔２４の第１活物質非形成部３４は、後述する絶縁層４０（図５～図８参照）で覆われている。なお、図３においては絶縁層４０の図示が省略されている。 As shown in FIGS. 3 and 4, the positive electrode sheet 21 includes a strip-shaped positive electrode metal foil 24 and positive electrode active material layers 25 formed on both sides of the positive electrode metal foil 24. The edges on both sides in the width direction (short direction) of the positive electrode metal foil 24 are formed to extend linearly along the longitudinal direction of the positive electrode metal foil 24 . On one side of the positive electrode metal foil 24 in the width direction (lower side in FIGS. 3 and 4), a positive electrode active material layer 25 is provided up to the edge of the positive electrode metal foil 24. At the edge of the other widthwise side (the upper side in FIGS. 3 and 4) of the positive electrode metal foil 24, the positive electrode active material layer 25 is not provided, and a first active material non-formed portion is provided where the positive electrode metal foil 24 is exposed. 34 are provided. The first active material non-forming portion 34 of the positive electrode metal foil 24 is covered with an insulating layer 40 (see FIGS. 5 to 8), which will be described later. Note that in FIG. 3, illustration of the insulating layer 40 is omitted.

正極金属箔２４の材料には、例えばアルミニウムが用いられるが、これ以外の金属を用いてもよい。正極活物質としては、例えば、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）、ニッケルコバルトマンガン酸リチウム（ＬｉＮｉｘＣｏｙＭｎ１－ｘ－ｙＯ２）、コバルト酸リチウム（ＬｉＣｏＯ２）、ニッケル酸リチウム（ＬｉＮｉＯ２）、リン酸鉄リチウム（ＬｉＦｅＰＯ４）、リン酸マンガンリチウム（ＬｉＭｎＰＯ４）、これらに置換添加物を用いたもの、又は、これらの混合物などが用いられるが、他のリチウム含有遷移金属酸化物を用いてもよい。 For example, aluminum is used as the material for the positive electrode metal foil 24, but other metals may also be used. Examples of positive electrode active materials include lithium manganate (LiMn2O4), lithium nickel cobalt manganate (LiNixCoyMn1-x-yO2), lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium iron phosphate (LiFePO4), Lithium manganese phosphate (LiMnPO4), substituted additives thereof, or mixtures thereof are used, but other lithium-containing transition metal oxides may also be used.

負極シート２２は、帯状の負極金属箔２６と、この負極金属箔２６の両面に形成された負極活物質層２７とを備える。負極金属箔２６の幅方向（短手方向）両側の縁部は、負極金属箔２６の長手方向に沿って直線状に延びるように形成されている。負極金属箔２６の幅方向の両側（図３及び図４において上側及び下側）において、負極活物質層２７は負極金属箔２６の縁部まで設けられている。これにより、負極金属箔２６の各面の全体が負極活物質層２７で被覆されている。 The negative electrode sheet 22 includes a strip-shaped negative electrode metal foil 26 and negative electrode active material layers 27 formed on both sides of the negative electrode metal foil 26. The edges on both sides in the width direction (short direction) of the negative electrode metal foil 26 are formed to extend linearly along the longitudinal direction of the negative electrode metal foil 26 . The negative electrode active material layer 27 is provided up to the edge of the negative electrode metal foil 26 on both sides of the negative electrode metal foil 26 in the width direction (upper and lower sides in FIGS. 3 and 4). Thereby, each surface of the negative electrode metal foil 26 is entirely covered with the negative electrode active material layer 27.

負極金属箔２６の材料には、例えば銅が用いられるが、これ以外の金属を用いてもよい。負極活物質としては、例えばグラファイトが用いられるが、他の炭素材料、リチウム金属、リチウム合金、チタン酸リチウム（Ｌｉ４Ｔｉ５Ｏ１２）、ケイ素、一酸化ケイ素、スズ等のリチウム吸蔵可能な材料、またはこれらの混合物を用いてもよい。 For example, copper is used as the material for the negative electrode metal foil 26, but other metals may also be used. As the negative electrode active material, for example, graphite is used, but other carbon materials, lithium metal, lithium alloy, lithium titanate (Li4Ti5O12), silicon, silicon monoxide, tin, or other materials capable of occluding lithium, or mixtures thereof may also be used. may also be used.

以下の説明では、正極シート２１、負極シート２２及びセパレータ２３の長手方向（図４～図８における矢印Ｐ方向）を単に「長手方向Ｐ」、正極シート２１、負極シート２２及びセパレータ２３の短手方向（図４～図８における矢印Ｑ方向）を単に「短手方向Ｑ」、正極シート２１、負極シート２２及びセパレータ２３の厚み方向（図５～図８における矢印Ｒ方向）を単に「厚み方向Ｒ」という。なお、長手方向Ｐは、特許請求の範囲の「第１方向」に相当するものである。短手方向Ｑは、特許請求の範囲の「第２方向」に相当するものであり、電極体２０の巻回軸Ｘ（図３参照）に平行な幅方向である。 In the following explanation, the longitudinal direction of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 (the direction of the arrow P in FIGS. 4 to 8) will be simply referred to as the "longitudinal direction P", and the short direction of the positive electrode sheet 21, the negative electrode sheet 22, and the separator 23 will be referred to as the "longitudinal direction P". The direction (direction of arrow Q in FIGS. 4 to 8) is simply referred to as "short direction Q," and the thickness direction (direction of arrow R in FIGS. 5 to 8) of positive electrode sheet 21, negative electrode sheet 22, and separator 23 is simply referred to as "thickness direction." It's called "R". Note that the longitudinal direction P corresponds to the "first direction" in the claims. The lateral direction Q corresponds to the "second direction" in the claims, and is the width direction parallel to the winding axis X (see FIG. 3) of the electrode body 20.

図４に示すように、正極シート２１及び負極シート２２の短手方向Ｑにおいて、負極シート２２の幅は、正極シート２１の幅よりも大きい。負極シート２２は、短手方向Ｑの両側において正極シート２１の縁部よりも外側に突出している。セパレータ２３の幅は、負極シート２２の幅よりも大きい。セパレータ２３は、短手方向Ｑの両側において負極シート２２の縁部よりも外側に突出している。 As shown in FIG. 4, the width of the negative electrode sheet 22 is larger than the width of the positive electrode sheet 21 in the transverse direction Q of the positive electrode sheet 21 and the negative electrode sheet 22. The negative electrode sheet 22 protrudes outward from the edge of the positive electrode sheet 21 on both sides in the transverse direction Q. The width of the separator 23 is larger than the width of the negative electrode sheet 22. The separator 23 protrudes outward from the edge of the negative electrode sheet 22 on both sides in the transverse direction Q.

図３及び図４に示すように、正極金属箔２４には、短手方向Ｑの一方側（図３及び図４における上側）の縁部に沿って直線状に延びる上記の第１活物質非形成部３４から短手方向Ｑ外向きに突出する複数の正極タブ（特許請求の範囲の「第１タブ」に相当）３５が、長手方向Ｐに間隔をあけて設けられている。第１活物質非形成部３４と複数の正極タブ３５は、１枚の正極金属箔２４で構成されており、各正極タブ３５は、第１活物質非形成部３４に一体に連なっている。正極タブ３５は、正極金属箔２４の表面に活物質層が形成されていない第２活物質非形成部とされている。 As shown in FIGS. 3 and 4, the positive electrode metal foil 24 has a non-containing portion of the first active material that extends linearly along one edge of the transverse direction Q (the upper side in FIGS. 3 and 4). A plurality of positive electrode tabs 35 (corresponding to "first tabs" in the claims) projecting outward in the transverse direction Q from the forming portion 34 are provided at intervals in the longitudinal direction P. The first active material non-forming portion 34 and the plurality of positive electrode tabs 35 are made of one sheet of positive electrode metal foil 24, and each positive electrode tab 35 is integrally connected to the first active material non-forming portion 34. The positive electrode tab 35 is a second active material non-forming portion in which no active material layer is formed on the surface of the positive electrode metal foil 24 .

図５に示すように、正極タブ３５の基部３５ａにおいて、長手方向Ｐにおける正極タブ３５の縁部と短手方向Ｑにおける第１活物質非形成部３４の縁部とのコーナ部にアール３５ｆが付けられている。アール３５ｆ，３５ｆは、長手方向Ｐにおける基部３５ａの両縁部に設けられている。これにより、長手方向Ｐにおける基部３５ａの幅は、第１活物質非形成部３４に近づくにつれて次第に大きくなっている。このようなアール３５ｆ，３５ｆが設けられていることにより、正極タブ３５の基部３５ａ、特にコーナ部にかかる応力集中を分散させることができ、基部３５ａでの破断が抑制される。つまり、正極タブ３５の基部３５ａの強度が高められている。 As shown in FIG. 5, in the base 35a of the positive electrode tab 35, a radius 35f is formed at the corner between the edge of the positive electrode tab 35 in the longitudinal direction P and the edge of the first active material non-formed part 34 in the transverse direction Q. It is attached. The radiuses 35f, 35f are provided at both edges of the base 35a in the longitudinal direction P. As a result, the width of the base portion 35a in the longitudinal direction P gradually increases as it approaches the first active material non-forming portion 34. By providing such radiuses 35f, 35f, it is possible to disperse stress concentration on the base 35a of the positive electrode tab 35, particularly on the corner portion, and to suppress breakage at the base 35a. In other words, the strength of the base portion 35a of the positive electrode tab 35 is increased.

図３及び図４に示すように、負極金属箔２６にも、正極タブ３５と同様の複数の負極タブ（特許請求の範囲の「第２タブ」に相当）３７が設けられている。負極タブ３７は、短手方向Ｑにおいて、正極タブ３５と同じ側に突出して設けられている。負極タブ３７における基端部を除く大部分は、負極金属箔２６の表面に活物質層が形成されていない活物質非形成部とされている。 As shown in FIGS. 3 and 4, the negative electrode metal foil 26 is also provided with a plurality of negative electrode tabs 37 (corresponding to "second tabs" in the claims) similar to the positive electrode tabs 35. The negative electrode tab 37 is provided so as to protrude on the same side as the positive electrode tab 35 in the lateral direction Q. Most of the negative electrode tab 37 except for the base end is an active material non-forming portion where no active material layer is formed on the surface of the negative electrode metal foil 26 .

図３に示すように、正極シート２１と負極シート２２がセパレータ２３，２３を介して重ね合わされて巻回されてなる電極体２０は、複数の正極タブ３５を積層してなる正極タブ束（特許請求の範囲の「第１タブ束」に相当）５５を備えている。正極タブ束５５は、電極体２０の一方のフラット部２０ｃに設けられている。 As shown in FIG. 3, the electrode body 20 is formed by stacking a positive electrode sheet 21 and a negative electrode sheet 22 with separators 23, 23 in between and winding them. (corresponding to the "first tab bundle" in the claims) 55. The positive electrode tab bundle 55 is provided on one flat portion 20c of the electrode body 20.

負極タブ３７は、長手方向Ｐにおいて正極タブ３５から間隔を空けて配置されており、正極タブ３５と負極タブ３７が相互に重なり合うことはない。巻回状態の電極体２０において、複数の負極タブ３７は互いに重ね合わされ、これにより、第２タブ束としての負極タブ束５７が形成されている。 The negative electrode tab 37 is spaced from the positive electrode tab 35 in the longitudinal direction P, and the positive electrode tab 35 and the negative electrode tab 37 do not overlap each other. In the wound electrode body 20, the plurality of negative electrode tabs 37 are stacked on top of each other, thereby forming a negative electrode tab bundle 57 as a second tab bundle.

正極タブ束５５と負極タブ束５７は、電極体２０の一方の端面部２０ａ（図３において上側の端面部）から突出している。また、電極体２０の端面部２０ａを巻回軸Ｘの延びる方向から見たときの長手方向の中心線Ｙに対し、一対のフラット部２０ｃ，２０ｃのうちの一方側（図３において手前側）から、正極タブ束５５と負極タブ束５７が突出している。 The positive electrode tab bundle 55 and the negative electrode tab bundle 57 protrude from one end surface 20a (the upper end surface in FIG. 3) of the electrode body 20. Moreover, one side of the pair of flat parts 20c, 20c (the near side in FIG. 3) with respect to the center line Y in the longitudinal direction when the end face part 20a of the electrode body 20 is viewed from the direction in which the winding axis X extends. A positive electrode tab bundle 55 and a negative electrode tab bundle 57 protrude from there.

図２に示すように、電極体２０の一方のフラット部２０ｃから突出した正極タブ束５５は、電極体２０の厚み方向Ｚ（巻回軸Ｘと中心線Ｙに直角な方向）における他方のフラット部２０ｃ側に倒されるように折り曲げられた状態で正極集電体１５に接続されている。 As shown in FIG. 2, the positive electrode tab bundle 55 protruding from one flat part 20c of the electrode body 20 is connected to the other flat part 20c in the thickness direction Z (direction perpendicular to the winding axis X and center line Y) of the electrode body 20. It is connected to the positive electrode current collector 15 in a bent state so as to be tilted toward the portion 20c side.

この状態において、正極タブ束５５を構成する各正極タブ３５は、その基部（基端から中間部に亘る部分）３５ａにおいて湾曲しており、各正極タブ３５の先端側部分（先端３５ｃから中間部に亘る部分）３５ｂは、電極体２０の端面部２０ａの上方に対向すると共に、正極集電体１５の第２平板部１５ｃの下面に沿って配置されている。 In this state, each of the positive electrode tabs 35 constituting the positive electrode tab bundle 55 is curved at its base portion (portion extending from the base end to the intermediate portion) 35a, and the tip side portion (from the tip end 35c to the intermediate portion) of each positive electrode tab 35 is curved. The portion 35b extending over the electrode body 20 is disposed opposite to the upper end surface portion 20a of the electrode body 20 and along the lower surface of the second flat plate portion 15c of the positive electrode current collector 15.

正極タブ束５５は、正極集電体１５の第２平板部１５ｃの下面に例えば超音波溶接により接合されている。これにより、各正極タブ３５は、正極集電体１５を介して正極の外部端子１１に電気的に接続されている。 The positive electrode tab bundle 55 is joined to the lower surface of the second flat plate portion 15c of the positive electrode current collector 15 by, for example, ultrasonic welding. Thereby, each positive electrode tab 35 is electrically connected to the positive electrode external terminal 11 via the positive electrode current collector 15.

図示は省略するが、負極タブ３７も同様に折り曲げられた状態で、負極集電体（図示せず）を介して負極の外部端子１２（図１参照）に電気的に接続されている。 Although not shown, the negative electrode tab 37 is similarly bent and electrically connected to the negative electrode external terminal 12 (see FIG. 1) via a negative electrode current collector (not shown).

以下、図５～図８を参照しながら、正極シート２１の絶縁層４０及びこれに関連する構成について説明する。 The insulating layer 40 of the positive electrode sheet 21 and related structures will be described below with reference to FIGS. 5 to 8.

図５は、正極シート２１の一方の面側から見た正極タブ３５及びその周辺部を示す拡大図、図６は、長手方向Ｐにおいて正極タブ３５からずれた部分における第１活物質非形成部３４及びその周辺部を長手方向Ｐから見た図５のＢ－Ｂ線断面図、図７は、正極タブ３５及びその周辺部を長手方向Ｐから見た図５のＣ－Ｃ線断面図、図８は、正極タブ３５及びその周辺部を正極タブ３５の突出方向（短手方向Ｑ）から見た図５のＤ－Ｄ線断面図である。 FIG. 5 is an enlarged view showing the positive electrode tab 35 and its surrounding area as seen from one side of the positive electrode sheet 21, and FIG. 6 is a portion where the first active material is not formed in a portion shifted from the positive electrode tab 35 in the longitudinal direction P. 5 is a sectional view taken along the line CC of FIG. 5 of the positive electrode tab 35 and its surroundings viewed from the longitudinal direction P, FIG. 7 is a sectional view taken along the line CC of FIG. FIG. 8 is a cross-sectional view taken along the line DD in FIG. 5, showing the positive electrode tab 35 and its surrounding area from the protruding direction (lateral direction Q) of the positive electrode tab 35.

図６及び図７に示すように、短手方向Ｑにおいて、負極活物質層２７は、正極活物質層２５よりも外側に突出して配置されている。これにより、蓄電素子１がリチウムイオン電池である場合、充電時に正極活物質層２５から放出されたリチウムイオンを負極活物質層２７に吸蔵させやすくなっている。 As shown in FIGS. 6 and 7, in the lateral direction Q, the negative electrode active material layer 27 is arranged to protrude outward from the positive electrode active material layer 25. Thereby, when the power storage element 1 is a lithium ion battery, lithium ions released from the positive electrode active material layer 25 during charging can be easily occluded in the negative electrode active material layer 27.

図５～図８に示すように、絶縁層４０は、短手方向Ｑにおける正極活物質層２５の一方の縁部に沿って、正極活物質層２５の縁部に隣接するように、正極金属箔２４の表面に設けられている。絶縁層４０は、正極金属箔２４の両面に設けられている。絶縁層４０は、正極金属箔２４の第１活物質非形成部３４に設けられた第１絶縁層部４１と、第２活物質非形成部である正極タブ３５に設けられた第２絶縁層部４２とを備えている。 As shown in FIGS. 5 to 8, the insulating layer 40 is formed of a cathode metal along one edge of the cathode active material layer 25 in the lateral direction Q so as to be adjacent to the edge of the cathode active material layer 25. It is provided on the surface of the foil 24. The insulating layer 40 is provided on both sides of the positive electrode metal foil 24. The insulating layer 40 includes a first insulating layer section 41 provided in the first active material non-forming part 34 of the positive electrode metal foil 24 and a second insulating layer part 41 provided in the positive electrode tab 35 which is the second active material non-forming part. 42.

図５及び図６に示すように、第１絶縁層部４１は、第１活物質非形成部３４の両側の表面において同様に設けられている。第１活物質非形成部３４の各表面において、第１絶縁層部４１は、短手方向Ｑにおける正極活物質層２５の上縁部に沿って形成されており、該正極活物質層２５の上縁部を覆っている。 As shown in FIGS. 5 and 6, the first insulating layer portions 41 are similarly provided on both surfaces of the first active material non-forming portion 34. As shown in FIGS. On each surface of the first active material non-forming part 34, the first insulating layer part 41 is formed along the upper edge of the positive electrode active material layer 25 in the transverse direction Q. Covers the upper edge.

第１絶縁層部４１は、短手方向Ｑにおいて正極金属箔２４の上端面２４ａよりも突出して形成されており、該上端面２４ａを覆っている。第１絶縁層部４１は、長手方向Ｐにおいて第１活物質非形成部３４の全長に亘って設けられている。これにより、第１活物質非形成部３４の両側の表面及び上端面２４ａは、第１絶縁層部４１によって完全に覆われている。 The first insulating layer portion 41 is formed to protrude from the upper end surface 24a of the positive electrode metal foil 24 in the lateral direction Q, and covers the upper end surface 24a. The first insulating layer section 41 is provided over the entire length of the first active material non-forming section 34 in the longitudinal direction P. As a result, both surfaces and the upper end surface 24a of the first active material non-forming portion 34 are completely covered with the first insulating layer portion 41.

図５に示すように、第２絶縁層部４２は、正極タブ３５の基部３５ａを含む領域に設けられている。より具体的に、第２絶縁層部４２は、正極タブ３５の基端から中間部に亘って設けられている。正極タブ３５の先端側部分３５ｂは、絶縁層４０に覆われることなく露出しており、これにより、先端側部分３５ｂにおける上述の集電体１５との接続が可能となっている。 As shown in FIG. 5, the second insulating layer portion 42 is provided in a region including the base portion 35a of the positive electrode tab 35. As shown in FIG. More specifically, the second insulating layer portion 42 is provided from the base end of the positive electrode tab 35 to the intermediate portion. The tip side portion 35b of the positive electrode tab 35 is exposed without being covered with the insulating layer 40, thereby enabling connection to the above-described current collector 15 at the tip side portion 35b.

図７に示すように、第２絶縁層部４２は、正極タブ３５の両側の表面において同様に設けられている。正極タブ３５の各表面において、第２絶縁層部４２は、短手方向Ｑにおいて第１絶縁層部４１の外側に一体に連なっている。短手方向Ｑにおいて、第２絶縁層部４２の上縁部４２ａは、負極シート２２の上縁部２２ａ及びセパレータ２３の上縁部２３ａよりも外側に位置している。 As shown in FIG. 7, the second insulating layer portions 42 are similarly provided on both surfaces of the positive electrode tab 35. As shown in FIG. On each surface of the positive electrode tab 35, the second insulating layer section 42 is integrally continuous with the outside of the first insulating layer section 41 in the transverse direction Q. In the transverse direction Q, the upper edge 42a of the second insulating layer section 42 is located outside the upper edge 22a of the negative electrode sheet 22 and the upper edge 23a of the separator 23.

このように、正極タブ３５の基部３５ａが絶縁層４０によって被覆されていることにより、短絡の発生を抑制しつつ、該基部３５ａを絶縁層４０によって補強することができる。正極タブ３５は、上述のように集電体１５との接続のために折り曲げられることから（図２参照）、該折り曲げによって湾曲した基部３５ａに応力が集中しやすいが、該基部３５ａが絶縁層４０によって補強されていることで、正極タブ３５の剛性を高め、耐久性の向上を図ることができる。 Since the base 35a of the positive electrode tab 35 is covered with the insulating layer 40 in this manner, the base 35a can be reinforced by the insulating layer 40 while suppressing the occurrence of short circuits. Since the positive electrode tab 35 is bent for connection with the current collector 15 as described above (see FIG. 2), stress tends to concentrate on the curved base 35a due to the bending, but the base 35a is By being reinforced by the positive electrode tab 40, the rigidity of the positive electrode tab 35 can be increased and durability can be improved.

また、正極タブ３５の基部３５ａの剛性が絶縁層４０によって高められていることにより、正極シート２１を巻回する際に、厚み方向Ｒに反るような正極タブ３５の撓みが抑制される。そのため、正極シート２１を巻回して複数の正極タブ３５を重ねるときに、正極タブ３５同士が引っ掛かり難くなり、これにより、各正極タブ３５の折れが抑制される。さらに、上述のように、基部３５ａにアール３５ｆ，３５ｆが付いているため、巻回時に正極シート２１にテンションがかかっても、基部３５ａへの応力集中が緩和され、基部３５ａの強度が更に向上する。 Further, since the rigidity of the base portion 35a of the positive electrode tab 35 is increased by the insulating layer 40, the positive electrode tab 35 is prevented from warping in the thickness direction R when the positive electrode sheet 21 is wound. Therefore, when the positive electrode sheet 21 is wound to stack a plurality of positive electrode tabs 35, the positive electrode tabs 35 are less likely to catch each other, thereby suppressing the bending of each positive electrode tab 35. Furthermore, as described above, since the base portion 35a has the radiuses 35f, 35f, even if tension is applied to the positive electrode sheet 21 during winding, stress concentration on the base portion 35a is alleviated, further improving the strength of the base portion 35a. do.

図８に示すように、絶縁層４０の第２絶縁層部４２は、長手方向Ｐの両側において正極タブ３５よりも外側に突出しており、正極タブ３５の両側の側端面３５ｄ，３５ｅを覆っている。これにより、正極タブ３５の基部３５ａは、正極タブ３５の両側の表面及び両側の側端面３５ｄ，３５ｅが第２絶縁層部４２によって覆われている。 As shown in FIG. 8, the second insulating layer portion 42 of the insulating layer 40 protrudes outward from the positive electrode tab 35 on both sides in the longitudinal direction P, and covers the side end surfaces 35d and 35e on both sides of the positive electrode tab 35. There is. As a result, in the base portion 35a of the positive electrode tab 35, the surfaces on both sides of the positive electrode tab 35 and the side end surfaces 35d and 35e on both sides are covered with the second insulating layer portion 42.

絶縁層４０の材料には、電気抵抗率が高い絶縁材料が用いられる。絶縁層４０の具体的な材料としては、例えば、無機および／または有機の粒子と結着剤とを混合したものが用いられる。無機物粒子としては、例えば、アルミナ（Ａｌ２Ｏ３）、ＳｉＯ２、ＺｒＯ２、ＴｉＯ２、ＭｇＯが用いられ、有機物粒子としては、例えば、ポリイミド粉末が用いられる。結着剤としては、例えば、ポリフッ化ビニリデン（ＰＶＤＦ）、ポリテトラフルオロエチレン（ＰＴＦＥ）、ポリイミド、ポリアミドイミドが用いられる。 As the material of the insulating layer 40, an insulating material with high electrical resistivity is used. As a specific material for the insulating layer 40, for example, a mixture of inorganic and/or organic particles and a binder is used. As the inorganic particles, for example, alumina (Al2O3), SiO2, ZrO2, TiO2, MgO are used, and as the organic particles, for example, polyimide powder is used. As the binder, for example, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyimide, or polyamideimide is used.

図６及び図７に示すように、絶縁層４０は、セパレータ２３を介して負極活物質層２７に対向配置されている。特に、絶縁層４０の第２絶縁層部４２は、短手方向Ｑにおいて、セパレータ２３の上縁部２３ａよりも突出している。そのため、セパレータ２３の位置ずれ、収縮又は破損を含む何らかの原因により正極シート２１における第１活物質非形成部３４及び正極タブ３５の基部３５ａと負極活物質層２７との間にセパレータ２３が介在しない部分が生じて、万一、正極シート２１と負極シート２２が接触しても、正極シート２１の金属部分を覆う絶縁層４０が、第１活物質非形成部３４及び正極タブ３５における金属箔２４と負極活物質層２７との間に介在することにより、短絡の防止が図られる。 As shown in FIGS. 6 and 7, the insulating layer 40 is disposed to face the negative electrode active material layer 27 with the separator 23 in between. In particular, the second insulating layer portion 42 of the insulating layer 40 protrudes beyond the upper edge portion 23a of the separator 23 in the transverse direction Q. Therefore, the separator 23 is not interposed between the first active material non-formed portion 34 in the positive electrode sheet 21 and the base 35a of the positive electrode tab 35 and the negative electrode active material layer 27 due to any cause including misalignment, contraction, or damage of the separator 23. Even if the positive electrode sheet 21 and negative electrode sheet 22 come into contact with each other due to contact between the positive electrode sheet 21 and the negative electrode sheet 22, the insulating layer 40 covering the metal portion of the positive electrode sheet 21 will not touch the metal foil 24 in the first active material non-formed portion 34 and the positive electrode tab 35. By being interposed between the negative electrode active material layer 27 and the negative electrode active material layer 27, short circuits can be prevented.

また、図６及び図８に示すように、絶縁層４０は、第１活物質非形成部３４及び正極タブ３５の基部３５ａの両側の表面だけでなく、これらの端面２４ａ，３５ｄ，３５ｅも被覆しているため、短絡の発生をより効果的に抑制できる。 Further, as shown in FIGS. 6 and 8, the insulating layer 40 covers not only the surfaces on both sides of the first active material non-forming portion 34 and the base portion 35a of the positive electrode tab 35, but also the end surfaces 24a, 35d, and 35e thereof. Therefore, the occurrence of short circuits can be suppressed more effectively.

仮に正極金属箔２４上に、正極電位で溶解する銅のような金属が混入した場合、該金属は、正極金属箔２４上で溶解する。このように溶解した金属が負極シート２２上に析出し、該金属の析出物が成長して正極シート２１に接触すると短絡を引き起こす。 If a metal such as copper that dissolves at the positive electrode potential is mixed onto the positive electrode metal foil 24, the metal will dissolve on the positive electrode metal foil 24. The thus dissolved metal precipitates on the negative electrode sheet 22, and when the metal precipitates grow and come into contact with the positive electrode sheet 21, a short circuit occurs.

しかしながら、本実施形態によれば、図６及び図７に示すように正極金属箔２４が絶縁層４０で覆われていることにより、負極シート２２の近傍に位置する正極金属箔２４上での金属の溶解が防止され、ひいては負極シート２２上での金属の析出を抑制でき、これにより、金属の析出物を起因とする短絡を防止できる。 However, according to the present embodiment, since the positive electrode metal foil 24 is covered with the insulating layer 40 as shown in FIGS. 6 and 7, the metal on the positive electrode metal foil 24 located near the negative electrode sheet 22 is This prevents the metal from dissolving and, in turn, suppresses metal precipitation on the negative electrode sheet 22, thereby preventing short circuits caused by metal precipitates.

さらに、第１活物質非形成部３４の上端面２４ａが絶縁層４０で被覆されることにより、この上端面２４ａでの短絡の抑制を図りつつ、該上端面２４ａよりも短手方向Ｑの外側に位置するセパレータ２３の上縁部２３ａに対して、上端面２４ａを近づけて配置しやすくなる。そのため、正極金属箔２４を短手方向Ｑに拡大することができ、これにより、電池容量の増大を図ることができる。 Further, by covering the upper end surface 24a of the first active material non-forming portion 34 with the insulating layer 40, short circuits at this upper end surface 24a can be suppressed, and the outer side of the upper end surface 24a in the transverse direction Q can be suppressed. It becomes easier to arrange the upper end surface 24a close to the upper edge 23a of the separator 23 located at the upper edge 23a of the separator 23. Therefore, the positive electrode metal foil 24 can be expanded in the lateral direction Q, thereby increasing the battery capacity.

ところで、正極タブ３５は、正極金属箔２４を所定形状にカットすることで形成される。より具体的には、正極金属箔２４における短手方向Ｑの一端部において、正極タブ３５に相当する部分を除いた残りの部分を切除することで、正極タブ３５が形成される。 Incidentally, the positive electrode tab 35 is formed by cutting the positive electrode metal foil 24 into a predetermined shape. More specifically, at one end of the positive electrode metal foil 24 in the transverse direction Q, the positive electrode tab 35 is formed by removing the portion corresponding to the positive electrode tab 35 and cutting off the remaining portion.

このような正極金属箔２４のカットにより、上記の第１活物質非形成部３４の上端面２４ａ及び正極タブ３５の側端面３５ｄ，３５ｅが形成され、その後、絶縁層４０の形成が行われる。このように、絶縁層４０の形成が、正極金属箔２４のカットの後に行われることにより、第１活物質非形成部３４及び正極タブ３５の端面２４ａ，３５ｄ，３５ｅを絶縁層４０によって被覆することができる。 By cutting the positive electrode metal foil 24 in this manner, the upper end surface 24a of the first active material non-forming portion 34 and the side end surfaces 35d and 35e of the positive electrode tab 35 are formed, and then the insulating layer 40 is formed. In this way, by forming the insulating layer 40 after cutting the positive electrode metal foil 24, the end surfaces 24a, 35d, and 35e of the first active material non-forming portion 34 and the positive electrode tab 35 are covered with the insulating layer 40. be able to.

絶縁層４０の形成は、例えばスロットダイ方式によるペースト状材料の塗布によって行われる。ただし、絶縁層４０の形成方法はこれに限定されるものでなく、例えば、静電粉体塗装によって、絶縁層４０を形成するようにしてもよい。 The insulating layer 40 is formed, for example, by applying a paste material using a slot die method. However, the method of forming the insulating layer 40 is not limited to this, and for example, the insulating layer 40 may be formed by electrostatic powder coating.

以上、上述の実施形態を挙げて本発明を説明したが、本発明は上述の実施形態に限定されるものではない。 Although the present invention has been described above with reference to the above-described embodiments, the present invention is not limited to the above-described embodiments.

例えば、上述の実施形態では、いわゆる巻回型の電極体２０を有する蓄電素子１について説明したが、本発明は、例えば図９に示すような所謂スタック型の電極体１２０（特許請求の範囲の「積層体」に相当）を有する蓄電素子にも適用できる。 For example, in the above-described embodiment, the electricity storage element 1 having a so-called wound type electrode body 20 has been described, but the present invention is also applicable to a so-called stacked type electrode body 120 as shown in FIG. It can also be applied to a power storage element having a "laminated body").

図９に示す電極体１２０は、複数の正極シート（特許請求の範囲の「第１電極シート」に相当）１２１と複数の負極シート（特許請求の範囲の「第２電極シート」に相当）１２２がセパレータ１２３を介して交互に積層されてなる積層体である。各正極シートは、上記と同様の第１活物質非形成部３４と第２活物質非形成部である正極タブ３５とを備え、各負極シート１２２は、上記と同様の負極タブ３７を備えている。電極体１２０は、各正極シート１２１に設けられた正極タブ３５を積層してなる正極タブ束と、各負極シート１２２に設けられた負極タブ３７を積層してなる負極タブ束とを備えている。 The electrode body 120 shown in FIG. 9 includes a plurality of positive electrode sheets 121 (corresponding to the "first electrode sheet" in the claims) 121 and a plurality of negative electrode sheets (corresponding to the "second electrode sheet" in the claims) 122. are stacked alternately with separators 123 in between. Each positive electrode sheet includes a first active material non-forming portion 34 similar to the above and a positive electrode tab 35 which is a second active material non-forming portion, and each negative electrode sheet 122 includes a negative electrode tab 37 similar to the above. There is. The electrode body 120 includes a positive electrode tab bundle formed by laminating positive electrode tabs 35 provided on each positive electrode sheet 121 and a negative electrode tab bundle formed by laminating negative electrode tabs 37 provided on each negative electrode sheet 122. .

このようなスタック型の電極体１２０においても、各正極シート１２１の第１活物質非形成部３４及び正極タブ３５に上記と同様の絶縁層４０が形成されることで、正極タブ３５の折り曲げによって応力が集中しやすい該タブ３５の基部を絶縁層によって補強できるなど、上述の実施形態と同様の効果を得ることができる。 In such a stacked electrode body 120 as well, an insulating layer 40 similar to that described above is formed on the first active material non-forming portion 34 and the positive electrode tab 35 of each positive electrode sheet 121, so that when the positive electrode tab 35 is bent, It is possible to obtain the same effects as in the above-described embodiments, such as being able to reinforce the base of the tab 35 where stress tends to concentrate with the insulating layer.

また、上述の実施形態では、第１活物質非形成部３４を構成する正極シート２１の縁部が延びる「第１方向」と、該縁部から正極タブ３５が突出する「第２方向」とが直角である例を説明したが、本発明において、第２方向は、第１方向に直角な方向に対して傾斜していてもよい。 Furthermore, in the above-described embodiment, there is a "first direction" in which the edge of the positive electrode sheet 21 constituting the first active material non-forming portion 34 extends, and a "second direction" in which the positive electrode tab 35 protrudes from the edge. In the present invention, the second direction may be inclined with respect to the direction perpendicular to the first direction.

さらに、上述の実施形態では、絶縁層が設けられる第１電極シートが正極シートである例を説明したが、本発明は、第１電極シートが負極シートである場合にも適用可能である。 Further, in the above-described embodiments, an example has been described in which the first electrode sheet provided with an insulating layer is a positive electrode sheet, but the present invention is also applicable to a case where the first electrode sheet is a negative electrode sheet.

本発明において、第１電極シートの金属箔は、必ずしも金属のみで構成されたものでなくてもよく、樹脂等からなる導電性のコート層（被膜）が金属の表面に形成されたものであってもよい。 In the present invention, the metal foil of the first electrode sheet does not necessarily have to be made of only metal, but may be one in which a conductive coating layer (film) made of resin or the like is formed on the surface of the metal. It's okay.

また、本発明において、第１電極シートの金属箔の表面に形成される絶縁層は、活物質層の縁部の表面に重なって形成されてもよく、或いは、活物質層の表面全体にオーバコートされてもよい。 Furthermore, in the present invention, the insulating layer formed on the surface of the metal foil of the first electrode sheet may be formed to overlap the surface of the edge of the active material layer, or may be formed to overlap the entire surface of the active material layer. May be coated.

さらに、上述の実施形態では、第１電極シートの金属箔の表面だけでなく端面にも絶縁層が形成される例を説明したが、本発明において、絶縁層は、必ずしも金属箔の端面に形成されなくてもよい。金属箔の端面に絶縁層を形成しない場合は、金属箔の表面に絶縁層を形成した後に、第１タブを形成するための第１電極シートのカットを行ってもよい。 Furthermore, in the above-described embodiment, an example was explained in which the insulating layer is formed not only on the surface of the metal foil of the first electrode sheet but also on the end surface. However, in the present invention, the insulating layer is not necessarily formed on the end surface of the metal foil. It doesn't have to be done. When an insulating layer is not formed on the end face of the metal foil, the first electrode sheet may be cut to form the first tab after forming the insulating layer on the surface of the metal foil.

またさらに、上述の実施形態では、第１タブの基部にアールが付けられる例を説明したが、本発明において、第１タブの基部には、必ずしもアールを付けなくてもよい。 Furthermore, in the above-described embodiment, an example in which the base of the first tab is rounded has been described, but in the present invention, the base of the first tab does not necessarily have to be rounded.

１ ：蓄電素子
１１ ：正極外部端子
１５ ：正極集電体
２０ ：電極体（巻回体）
２０ｃ ：フラット部
２０ｄ ：湾曲部
２１ ：正極シート（第１電極シート）
２２ ：負極シート（第２電極シート）
２２ａ ：負極シートの縁部
２３ ：セパレータ
２３ａ ：セパレータの縁部
２４ ：正極金属箔
２４ａ ：正極金属箔の端面
２５ ：正極活物質層
３４ ：第１活物質非形成部
３５ ：正極タブ（第１タブ）（第２活物質非形成部）
３５ａ ：正極タブの基部
３５ｃ ：正極タブの先端
３５ｄ，３５ｅ ：正極タブの側端面
３７ ：負極タブ（第２タブ）
４０ ：絶縁層
４１ ：第１絶縁層部
４２ ：第２絶縁層部
４２ａ ：第２絶縁層部の縁部
５５ ：正極タブ束（第１タブ束）
５７ ：負極タブ束（第２タブ束）
１２０ ：電極体（積層体）
１２１ ：正極シート（第１電極シート）
１２２ ：負極シート（第２電極シート）
１２３ ：セパレータ
Ｐ ：シートの長手方向（第１方向）
Ｑ ：シートの短手方向（第２方向）
Ｘ ：巻回軸 1: Energy storage element 11: Positive electrode external terminal 15: Positive electrode current collector 20: Electrode body (wound body)
20c: Flat part 20d: Curved part 21: Positive electrode sheet (first electrode sheet)
22: Negative electrode sheet (second electrode sheet)
22a: Edge of negative electrode sheet 23: Separator 23a: Edge of separator 24: Positive electrode metal foil 24a: End surface of positive electrode metal foil 25: Positive electrode active material layer 34: First active material non-forming area 35: Positive electrode tab (first tab) (second active material non-forming part)
35a: Base of positive electrode tab 35c: Tip of positive electrode tab 35d, 35e: Side end surface of positive electrode tab 37: Negative electrode tab (second tab)
40: Insulating layer 41: First insulating layer portion 42: Second insulating layer portion 42a: Edge of second insulating layer portion 55: Positive electrode tab bundle (first tab bundle)
57: Negative electrode tab bundle (second tab bundle)
120: Electrode body (laminate)
121: Positive electrode sheet (first electrode sheet)
122: Negative electrode sheet (second electrode sheet)
123: Separator P: Longitudinal direction of sheet (first direction)
Q: Width direction of sheet (second direction)
X: Winding axis

Claims (5)

第１電極シートと、セパレータを介して前記第１電極シートに積層され、前記第１電極シートとは異なる極性を有する第２電極シートと、を備えた蓄電素子であって、
前記第１電極シートは、
第１方向に延びる縁部、及び、該縁部から前記第１方向に交差する第２方向に突出した第１タブを有する金属箔と、
前記金属箔の表面に形成された活物質層と、
前記金属箔の表面に形成された絶縁層と、
を備え、
前記第２電極シートは、前記第１方向に延びる縁部、及び、該縁部から前記第２方向に延びる第２タブを有し、
前記第１タブと前記第２タブは、前記第２方向の同じ側に突出しており、
前記金属箔における前記縁部に沿う部分及び前記第１タブは、前記活物質層が形成されていない活物質非形成部とされ、
前記絶縁層は、前記活物質非形成部における前記縁部に沿う部分及び前記第１タブの基部を含む領域に設けられ、
前記縁部に沿う部分及び前記基部に設けられた前記絶縁層は、前記第２方向において前記活物質層と並んで配置され、かつ、一体に連なっており、
前記第１タブは、前記基部においてアールが付けられており、
前記絶縁層は、前記第１タブの前記アールを含む領域に形成されていることを特徴とする蓄電素子。 A power storage element comprising a first electrode sheet and a second electrode sheet laminated on the first electrode sheet with a separator interposed therebetween and having a polarity different from that of the first electrode sheet,
The first electrode sheet is
a metal foil having an edge extending in a first direction and a first tab protruding from the edge in a second direction intersecting the first direction;
an active material layer formed on the surface of the metal foil;
an insulating layer formed on the surface of the metal foil;
Equipped with
The second electrode sheet has an edge extending in the first direction and a second tab extending from the edge in the second direction,
The first tab and the second tab protrude on the same side in the second direction,
A portion of the metal foil along the edge and the first tab are active material non-formed portions in which the active material layer is not formed,
The insulating layer is provided in a region including a portion along the edge of the active material non-forming portion and a base of the first tab,
The insulating layer provided in the portion along the edge and the base is arranged in line with the active material layer in the second direction, and is continuous with the active material layer,
the first tab is rounded at the base;
The electric storage element is characterized in that the insulating layer is formed in a region of the first tab that includes the radius. 前記絶縁層における前記第１タブの表面に形成された部分は、前記第２方向において前記セパレータの縁部よりも突出していることを特徴とする請求項１に記載の蓄電素子。 The power storage element according to claim 1, wherein a portion of the insulating layer formed on the surface of the first tab protrudes from an edge of the separator in the second direction. 電極体を備えた蓄電素子であって、
前記電極体は、第１電極シートと、前記第１電極シートとは異なる極性を有する第２電極シートと、を有し、
前記第１電極シートは、
金属箔と、
前記金属箔に設けられた活物質層と、
前記金属箔に設けられた絶縁層と、
を備え、
前記金属箔は、前記活物質層が設けられていない活物質非形成部を有し、
前記活物質非形成部は、前記金属箔の所定方向の縁部に沿って延びる第１活物質非形成部と、前記第１活物質非形成部から突出した第１タブと、を有し、
前記絶縁層は、前記活物質非形成部における前記縁部に沿う部分及び前記第１タブの基部を含む領域に設けられ、
前記縁部に沿う部分及び前記基部に設けられた前記絶縁層は、前記所定方向において前記活物質層と並んで配置され、かつ、一体に連なっており、
前記第２電極シートは、縁部、及び、該縁部から突出した第２タブを有し、
前記第１タブと前記第２タブは、前記電極体の同一端面部から突出しており、
前記第１タブは、前記基部においてアールが付けられており、
前記絶縁層は、前記アールに沿って形成されていることを特徴とする蓄電素子。 A power storage element including an electrode body,
The electrode body has a first electrode sheet and a second electrode sheet having a different polarity from the first electrode sheet,
The first electrode sheet is
metal foil and
an active material layer provided on the metal foil;
an insulating layer provided on the metal foil;
Equipped with
The metal foil has an active material non-formed portion where the active material layer is not provided,
The active material non-forming part has a first active material non-forming part extending along an edge of the metal foil in a predetermined direction, and a first tab protruding from the first active material non-forming part,
The insulating layer is provided in a region including a portion along the edge of the active material non-forming portion and a base of the first tab,
The insulating layer provided on the portion along the edge and the base is arranged in line with the active material layer in the predetermined direction, and is continuous with the active material layer,
The second electrode sheet has an edge and a second tab protruding from the edge,
The first tab and the second tab protrude from the same end surface of the electrode body,
the first tab is rounded at the base;
A power storage element, wherein the insulating layer is formed along the radius. 前記絶縁層は、前記活物質層上、及び、前記活物質非形成部における前記第１タブの基部を含む領域に形成されていることを特徴とする請求項１から請求項３のいずれか１項に記載の蓄電素子。 Any one of claims 1 to 3, wherein the insulating layer is formed on the active material layer and in a region including the base of the first tab in the active material non-forming part. The energy storage element described in . 前記第１電極シートを外部端子に電気的に接続させる集電体を更に備え、
前記第１タブは、折り曲げられた状態で前記集電体に接続されていることを特徴とする請求項１から請求項４のいずれか１項に記載の蓄電素子。 further comprising a current collector that electrically connects the first electrode sheet to an external terminal,
The power storage element according to any one of claims 1 to 4, wherein the first tab is connected to the current collector in a bent state.
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