JP2022026712A - Power storage cell and power storage device - Google Patents

Power storage cell and power storage device Download PDF

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JP2022026712A
JP2022026712A JP2020130305A JP2020130305A JP2022026712A JP 2022026712 A JP2022026712 A JP 2022026712A JP 2020130305 A JP2020130305 A JP 2020130305A JP 2020130305 A JP2020130305 A JP 2020130305A JP 2022026712 A JP2022026712 A JP 2022026712A
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current collector
tubular member
welded
welding
storage cell
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幹也 栗田
Mikiya Kurita
亮太 磯村
Ryota Isomura
亮太 神谷
Ryota Kamiya
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Toyota Industries Corp
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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
    • 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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Abstract

To provide a power storage cell which can inhibit deterioration of sealability, and to provide a power storage device.SOLUTION: A power storage cell 10 includes: a positive electrode having a first collector 20; a negative electrode having a second collector 21; a seal member 14 which is welded to the first collector 20 and the second collector 21 in a lamination direction D; and a cylindrical member 30 which extends penetrating through the seal member 14. The power storage cell 10 has a welded auxiliary member 40 which is adhered to the cylindrical member 30 and welded to the second collector 21 between the cylindrical member 30 and the second collector 21 in the lamination direction D.SELECTED DRAWING: Figure 4

Description

本発明は、蓄電セル及び蓄電装置に関する。 The present invention relates to a power storage cell and a power storage device.

特許文献１に記載の蓄電モジュールは、複数のバイポーラ電極が積層された積層体と、バイポーラ電極の積層方向に延在する積層体の側面において、電極板の縁部を保持するシール部材としての枠体と、を備える。バイポーラ電極は、集電体としての上述の電極板と、電極板の第１面に位置する正極と、電極板の第２面に位置する負極とを含む。枠体は、電極板の縁部を保持する第１樹脂部と、第１樹脂部の周囲に設けられる第２樹脂部と、を備える。枠体は、隣り合うバイポーラ電極の間をシールしている。枠体は、隣り合うバイポーラ電極間の内部空間から電解液の漏れを抑制する。 The power storage module described in Patent Document 1 is a frame as a seal member that holds an edge of an electrode plate on a side surface of a laminate in which a plurality of bipolar electrodes are laminated and a laminate extending in the stacking direction of the bipolar electrodes. Prepare with the body. The bipolar electrode includes the above-mentioned electrode plate as a current collector, a positive electrode located on the first surface of the electrode plate, and a negative electrode located on the second surface of the electrode plate. The frame body includes a first resin portion that holds the edge portion of the electrode plate, and a second resin portion that is provided around the first resin portion. The frame seals between adjacent bipolar electrodes. The frame suppresses leakage of the electrolytic solution from the internal space between adjacent bipolar electrodes.

枠体は、当該枠体内に電解液を注入するための注液口を備える。注液口は、第１樹脂部に設けられた第１開口と、第２樹脂部に設けられた第２開口と、を備える。第１開口は、隣り合うバイポーラ電極間の内部空間及び第２開口と連通する。電解液は、第２開口から第１開口を経由して枠体内に注入される。具体的には、注入装置の供給管の先端を、第２開口を通じて第１開口に位置させ、供給管から第１開口を介して枠体内に電解液を注入する。 The frame body is provided with an injection port for injecting an electrolytic solution into the frame body. The liquid injection port includes a first opening provided in the first resin portion and a second opening provided in the second resin portion. The first opening communicates with the internal space between adjacent bipolar electrodes and the second opening. The electrolytic solution is injected into the frame body from the second opening via the first opening. Specifically, the tip of the supply pipe of the injection device is positioned at the first opening through the second opening, and the electrolytic solution is injected from the supply pipe through the first opening into the frame.

ところが、枠体内に電解液を注入する際、供給管の先端によって枠体が損傷する虞がある。
そこで、発明者は、筒部材を、集電体（電極板）に予め接合しておき、筒部材に電解液の供給管を挿入して電解液の注入を行うことを考えた。筒部材に供給管を挿入することで、枠体に対する直接の供給管の接触が回避され、枠体の損傷が回避される。 However, when the electrolytic solution is injected into the frame body, the frame body may be damaged by the tip of the supply pipe.
Therefore, the inventor considered to join the tubular member to the current collector (electrode plate) in advance and insert the electrolytic solution supply pipe into the tubular member to inject the electrolytic solution. By inserting the supply pipe into the tubular member, direct contact of the supply pipe with the frame body is avoided, and damage to the frame body is avoided.

特開２０１８－１０１４８６号公報Japanese Unexamined Patent Publication No. 2018-101486

しかしながら、集電体に筒部材を接合した構成において、集電体と筒部材との密着性が低いと、集電体と筒部材との接合箇所におけるシール性が低下する虞がある。
本発明は、上記課題を解決するためになされたものであって、その目的は、シール性の低下を抑制することができる蓄電セル及び蓄電装置を提供することにある。 However, in a configuration in which the current collector is joined to the cylinder member, if the adhesion between the current collector and the cylinder member is low, the sealing property at the joint portion between the current collector and the cylinder member may be deteriorated.
The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage cell and a power storage device capable of suppressing deterioration of sealing property.

上記課題を解決する蓄電セルは、第１集電体を有する正極と、第２集電体を有する負極と、前記正極と前記負極とが重なり合う積層方向において前記第１集電体及び前記第２集電体に溶着するシール部材と、前記シール部材を貫通して延びる筒部材と、前記積層方向における前記筒部材と、前記第１集電体及び前記第２集電体のいずれか一方の被溶着集電体と、の間において、前記筒部材に密着し、かつ前記被溶着集電体に溶着している溶着補助部材と、を有する。 The storage cell that solves the above problems includes the first current collector and the second current collector in a stacking direction in which a positive electrode having a first current collector, a negative electrode having a second current collector, and the positive electrode and the negative electrode overlap each other. A seal member welded to the current collector, a tubular member extending through the seal member, the tubular member in the stacking direction, and a cover of either the first current collector or the second current collector. Between the welded current collector, there is a welding auxiliary member that is in close contact with the tubular member and is welded to the welded current collector.

これによれば、溶着補助部材と被溶着集電体とが溶着され、溶着補助部材と被溶着集電体とが密着する。
上記蓄電セルにおいて、前記溶着補助部材は、前記筒部材と前記シール部材との間に介在するとともに前記シール部材に溶着しているとよい。 According to this, the welding assisting member and the welded current collector are welded, and the welding assisting member and the welded current collector are brought into close contact with each other.
In the storage cell, the welding assisting member may be interposed between the tubular member and the sealing member and welded to the sealing member.

これによれば、溶着補助部材とシール部材とが溶着され、溶着補助部材とシール部材とが密着する。
上記蓄電セルにおいて、前記溶着補助部材の材料は、前記シール部材の材料と同じであるとよい。 According to this, the welding assisting member and the sealing member are welded, and the welding assisting member and the sealing member are brought into close contact with each other.
In the storage cell, the material of the welding auxiliary member may be the same as the material of the sealing member.

これによれば、シール部材と溶着補助部材とをより溶着させ易くすることができ、シール部材の材料と溶着補助部材の材料とが異なる場合に比べてシール部材と溶着補助部材とを密着させ易くすることができる。 According to this, it is possible to make it easier to weld the seal member and the welding assisting member, and it is easier to bring the sealing member and the welding assisting member into close contact with each other as compared with the case where the material of the sealing member and the material of the welding assisting member are different. can do.

上記蓄電セルにおいて、前記筒部材は、前記第１集電体と前記第２集電体と前記シール部材とによって画定される空間の外部から当該空間の内部へ電解液を注入するために用いられ、前記筒部材は、前記筒部材の前記空間の外部寄りの端部を閉塞する閉塞部と、前記閉塞部から前記筒部材の軸方向に沿って延びる通路と、を有するとよい。 In the storage cell, the tubular member is used to inject an electrolytic solution from the outside of the space defined by the first current collector, the second current collector, and the seal member into the space. The tubular member may have a closed portion that closes the outer end of the space of the tubular member, and a passage that extends from the closed portion along the axial direction of the tubular member.

これによれば、電解液を空間の内部に注入するために筒部材が用いられるが、閉塞部により、通路を通じて電解液が空間の内部から外部へ洩れ出ることを防止できる。
上記蓄電セルにおいて、前記溶着補助部材は、前記筒部材の軸方向に沿って延びており、前記溶着補助部材の前記積層方向及び前記軸方向と直交する第１方向における寸法は、前記軸方向に沿って前記第１集電体と前記第２集電体と前記シール部材とによって画定される空間の内部から前記空間の外部に近づくに従い変化しているとよい。 According to this, a tubular member is used to inject the electrolytic solution into the space, but the closed portion can prevent the electrolytic solution from leaking from the inside of the space to the outside through the passage.
In the electricity storage cell, the welding assisting member extends along the axial direction of the tubular member, and the dimensions of the welding assisting member in the laminating direction and the first direction orthogonal to the axial direction are in the axial direction. It is preferable that the change is made from the inside of the space defined by the first current collector, the second current collector, and the seal member as it approaches the outside of the space.

例えば、蓄電セルの内圧が上昇し、上昇した内圧が溶着補助部材に作用すると、溶着補助部材が、蓄電セルの外部に向けて押圧される。溶着補助部材を押圧する力は、軸方向に作用する。突出部は、軸方向に直交する第１方向に突出している。そして、突出部の第１方向への寸法は、軸方向に沿って変化する形状である。このため、溶着補助部材とシール部材との界面が、軸方向に沿って延びる場合と比べると界面の長さを長くでき、溶着補助部材とシール部材との界面での応力集中を緩和することができる。 For example, when the internal pressure of the electricity storage cell rises and the increased internal pressure acts on the welding assisting member, the welding assisting member is pressed toward the outside of the electricity storage cell. The force that presses the welding assist member acts in the axial direction. The protruding portion protrudes in the first direction orthogonal to the axial direction. The dimension of the protrusion in the first direction is a shape that changes along the axial direction. Therefore, the length of the interface between the welding assisting member and the sealing member can be made longer than that in the case where the interface extends along the axial direction, and the stress concentration at the interface between the welding assisting member and the sealing member can be relaxed. can.

上記蓄電セルにおいて、前記シール部材は、前記積層方向において前記筒部材と重なる位置に、前記積層方向に沿って前記被溶着集電体から離れるように凹む凹部を有するとよい。 In the storage cell, the seal member may have a recess in the position where it overlaps with the cylinder member in the stacking direction so as to be separated from the welded current collector along the stacking direction.

これによれば、凹部を有しない場合に比べて、積層方向への凹部の寸法の分だけ蓄電セルの厚みが厚くなることを抑制することができる。
上記蓄電セルにおいて、前記積層方向への前記凹部の寸法は、前記積層方向への前記筒部材の寸法と前記積層方向への前記溶着補助部材の寸法との和以上であるとよい。 According to this, it is possible to suppress the thickness of the storage cell from becoming thicker by the size of the recess in the stacking direction as compared with the case where the recess is not provided.
In the storage cell, the dimension of the recess in the stacking direction may be equal to or greater than the sum of the dimension of the tubular member in the stacking direction and the dimension of the welding assisting member in the stacking direction.

これによれば、筒部材及び溶着補助部材を配置した箇所が局所的に厚くなることを抑制することができる。
上記課題を解決する蓄電装置は、積層された複数の蓄電セルを有し、前記複数の前記蓄電セルは、請求項１～請求項７のいずれか一項に記載の前記蓄電セルを含む。 According to this, it is possible to suppress the local thickening of the portion where the tubular member and the welding assist member are arranged.
The power storage device for solving the above problems has a plurality of stacked power storage cells, and the plurality of power storage cells include the power storage cell according to any one of claims 1 to 7.

これによれば、積層された複数の蓄電セルについて、溶着補助部材と被溶着集電体とが溶着され、溶着補助部材と被溶着集電体とが密着する。 According to this, the welding assisting member and the welded current collector are welded to the plurality of stacked storage cells, and the welding assisting member and the welded current collector are brought into close contact with each other.

この発明によれば、シール性の低下を抑制することができる。 According to the present invention, it is possible to suppress a decrease in sealing property.

実施形態における蓄電装置を示す断面図。FIG. 3 is a sectional view showing a power storage device according to an embodiment. 蓄電セルの一部分を示す断面図。Sectional drawing which shows a part of a storage cell. 蓄電セルを示す模式図。The schematic diagram which shows the storage cell. 図２における４－４線断面図。FIG. 2 is a sectional view taken along line 4-4 in FIG. 蓄電セルの一部分を拡大して示す模式図。The schematic diagram which shows the part of the storage cell enlarged. 別の実施形態における蓄電セルの一部分を示す断面図。FIG. 6 is a cross-sectional view showing a part of a storage cell in another embodiment.

以下、蓄電セル及び蓄電装置を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１は、複数の蓄電セル１０を積層したセルスタック２を含んで構成されている。蓄電セル１０が積層される方向を積層方向Ｄとする。蓄電セル１０は、正極１１と、負極１２と、セパレータ１３と、シール部材１４とを備える。正極１１は、第１集電体２０と、第１集電体２０の第１面２０ａに位置する正極活物質層２２と、を有する。正極１１は、例えば矩形状の電極である。負極１２は、第２集電体２１と、第２集電体２１の第１面２１ａに位置する負極活物質層２３と、を有する。負極１２は、例えば矩形状の電極である。正極１１の第１面２０ａと負極１２の第１面２１ａとは積層方向Ｄに対向する。つまり、正極１１と負極１２は重なり合っている。正極１１と負極１２が重なり合う積層方向は、蓄電セル１０の積層方向Ｄと一致する。負極活物質層２３は、セパレータ１３を介して正極活物質層２２と対向するように配置されている。正極活物質層２２及び負極活物質層２３は、それぞれ矩形状に形成されている。負極活物質層２３は、正極活物質層２２よりも一回り大きく形成されている。積層方向Ｄから見た平面視において、正極活物質層２２の形成領域の全体が、負極活物質層２３の形成領域の内側に位置している。 Hereinafter, an embodiment in which the power storage cell and the power storage device are embodied will be described with reference to FIGS. 1 to 5.
As shown in FIG. 1, the power storage device 1 includes a cell stack 2 in which a plurality of power storage cells 10 are stacked. The direction in which the storage cells 10 are stacked is defined as the stacking direction D. The storage cell 10 includes a positive electrode 11, a negative electrode 12, a separator 13, and a sealing member 14. The positive electrode 11 has a first current collector 20 and a positive electrode active material layer 22 located on the first surface 20a of the first current collector 20. The positive electrode 11 is, for example, a rectangular electrode. The negative electrode 12 has a second current collector 21 and a negative electrode active material layer 23 located on the first surface 21a of the second current collector 21. The negative electrode 12 is, for example, a rectangular electrode. The first surface 20a of the positive electrode 11 and the first surface 21a of the negative electrode 12 face each other in the stacking direction D. That is, the positive electrode 11 and the negative electrode 12 overlap each other. The stacking direction in which the positive electrode 11 and the negative electrode 12 overlap with each other coincides with the stacking direction D of the storage cell 10. The negative electrode active material layer 23 is arranged so as to face the positive electrode active material layer 22 via the separator 13. The positive electrode active material layer 22 and the negative electrode active material layer 23 are each formed in a rectangular shape. The negative electrode active material layer 23 is formed to be one size larger than the positive electrode active material layer 22. In a plan view from the stacking direction D, the entire forming region of the positive electrode active material layer 22 is located inside the forming region of the negative electrode active material layer 23.

第１集電体２０は、第１面２０ａとは反対側の面である第２面２０ｂを有する。第２面２０ｂには、正極活物質層２２が形成されていない。第１集電体２０の第２面２０ｂと第２集電体２１の第２面２１ｂとが互いに接するように、蓄電セル１０がスタックされることによってセルスタック２が構成される。これにより、複数の蓄電セル１０が電気的に直列に接続される。セルスタック２では、隣り合う蓄電セル１０により互いに接する第１集電体２０及び第２集電体２１を電極体とする疑似的なバイポーラ電極３が形成される。すなわち、１つのバイポーラ電極３は、第１集電体２０、第２集電体２１、正極活物質層２２、及び負極活物質層２３を含む。 The first current collector 20 has a second surface 20b which is a surface opposite to the first surface 20a. The positive electrode active material layer 22 is not formed on the second surface 20b. The cell stack 2 is formed by stacking the storage cells 10 so that the second surface 20b of the first current collector 20 and the second surface 21b of the second current collector 21 are in contact with each other. As a result, the plurality of storage cells 10 are electrically connected in series. In the cell stack 2, a pseudo bipolar electrode 3 having a first current collector 20 and a second current collector 21 in contact with each other is formed by adjacent storage cells 10. That is, one bipolar electrode 3 includes a first current collector 20, a second current collector 21, a positive electrode active material layer 22, and a negative electrode active material layer 23.

蓄電装置１における積層方向Ｄの第１端部６には、終端電極として第１集電体２０が配置される。蓄電装置１における積層方向Ｄの第２端部７には、終端電極として第２集電体２１が配置される。 A first current collector 20 is arranged as a terminal electrode at the first end 6 of the stacking direction D in the power storage device 1. A second current collector 21 is arranged as a terminal electrode at the second end portion 7 of the stacking direction D in the power storage device 1.

蓄電装置１は、積層方向Ｄにおいてセルスタック２を挟むように配置された、正極通電板６０及び負極通電板７０からなる一対の通電体を備える。正極通電板６０及び負極通電板７０は、それぞれ両導電性材料で構成される。正極通電板６０は、積層方向Ｄの第１端部６において最も外側に配置された第１集電体２０に電気的に接続される。負極通電板７０は、積層方向Ｄの第２端部７において最も外側に配置された第２集電体２１に電気的に接続される。正極通電板６０及び負極通電板７０のそれぞれに設けられた端子を通じて蓄電装置１の充放電が行われる。正極通電板６０及び負極通電板７０のそれぞれを構成する材料としては、第１集電体２０及び第２集電体２１を構成する材料と同じを用いることができる。正極通電板６０及び負極通電板７０のそれぞれは、セルスタック２に用いられた第１集電体２０及び第２集電体２１よりも厚い金属板で構成してもよい。 The power storage device 1 includes a pair of energizing bodies composed of a positive electrode energizing plate 60 and a negative electrode energizing plate 70 arranged so as to sandwich the cell stack 2 in the stacking direction D. The positive electrode energizing plate 60 and the negative electrode energizing plate 70 are each made of both conductive materials. The positive electrode current-carrying plate 60 is electrically connected to the first current collector 20 arranged on the outermost side at the first end portion 6 in the stacking direction D. The negative electrode energizing plate 70 is electrically connected to the second current collector 21 arranged on the outermost side at the second end portion 7 in the stacking direction D. Charging / discharging of the power storage device 1 is performed through terminals provided on each of the positive electrode energizing plate 60 and the negative electrode energizing plate 70. As the material constituting each of the positive electrode energizing plate 60 and the negative electrode energizing plate 70, the same materials as those constituting the first current collector 20 and the second current collector 21 can be used. Each of the positive electrode current-carrying plate 60 and the negative electrode current-carrying plate 70 may be made of a metal plate thicker than the first current collector 20 and the second current collector 21 used in the cell stack 2.

第１集電体２０及び第２集電体２１は、化学的に不活性な電気伝導体である。第１集電体２０及び第２集電体２１を構成する材料としては、例えば、金属材料、導電性樹脂材料、導電性無機材料等を用いることができる。導電性樹脂材料としては、例えば、導電性高分子材料又は非導電性高分子材料に必要に応じて導電性フィラーが添加された樹脂等が挙げられる。第１集電体２０及び第２集電体２１は、前述した金属材料又は導電性樹脂材料を含む１以上の層を含む複数層を備えてもよい。第１集電体２０及び第２集電体２１の表面に、メッキ処理又はスプレーコート等の公知の方法により被覆層を形成してもよい。第１集電体２０及び第２集電体２１は、例えば、板状、箔状、シート状、フィルム状、メッシュ状等の形態に形成されていてもよい。第１集電体２０及び第２集電体２１を金属箔とする場合、例えば、アルミニウム箔、銅箔、ニッケル箔、チタン箔、又はステンレス鋼箔等を用いることができる。第１集電体２０及び第２集電体２１としてステンレス鋼箔を用いる場合、例えばＪＩＳ Ｇ ４３０５：２０１５にて規定されるＳＵＳ３０４、ＳＵＳ３１６、ＳＵＳ３０１、ＳＵＳ３０４等を用いると、第１集電体２０及び第２集電体２１の機械的強度を確保することができる。第１集電体２０及び第２集電体２１は、上記金属の合金箔又はクラッド箔であってもよい。本実施形態において、第１集電体２０はアルミニウム箔であり、第２集電体２１は銅箔である。第１集電体２０及び第２集電体２１は、箔状である場合、厚みを例えば、１μｍ～１００μｍとすればよい。 The first current collector 20 and the second current collector 21 are chemically inert electric conductors. As the material constituting the first current collector 20 and the second current collector 21, for example, a metal material, a conductive resin material, a conductive inorganic material, or the like can be used. Examples of the conductive resin material include a conductive polymer material and a resin obtained by adding a conductive filler to a non-conductive polymer material as needed. The first current collector 20 and the second current collector 21 may include a plurality of layers including one or more layers including the above-mentioned metal material or conductive resin material. A coating layer may be formed on the surfaces of the first current collector 20 and the second current collector 21 by a known method such as plating or spray coating. The first current collector 20 and the second current collector 21 may be formed in, for example, a plate shape, a foil shape, a sheet shape, a film shape, a mesh shape, or the like. When the first current collector 20 and the second current collector 21 are metal foils, for example, aluminum foil, copper foil, nickel foil, titanium foil, stainless steel foil and the like can be used. When stainless steel foil is used as the first current collector 20 and the second current collector 21, for example, when SUS304, SUS316, SUS301, SUS304, etc. specified in JIS G 4305: 2015 are used, the first current collector 20 is used. And the mechanical strength of the second current collector 21 can be ensured. The first current collector 20 and the second current collector 21 may be the alloy foil or the clad foil of the metal. In the present embodiment, the first current collector 20 is an aluminum foil and the second current collector 21 is a copper foil. When the first current collector 20 and the second current collector 21 are foil-shaped, the thickness may be, for example, 1 μm to 100 μm.

正極活物質層２２は、リチウムイオン等の電荷担体を吸蔵及び放出し得る正極活物質を含む。正極活物質としては、層状岩塩構造を有するリチウム複合金属酸化物、スピネル構造の金属酸化物、ポリアニオン系化合物など、リチウムイオン二次電池の正極活物質として使用可能なものを採用すればよい。また、２種以上の正極活物質を併用してもよい。本実施形態において、正極活物質層２２は複合活物質としてのオリビン型リン酸鉄リチウム（ＬｉＦｅＰＯ４）を含む。 The positive electrode active material layer 22 contains a positive electrode active material that can occlude and release charge carriers such as lithium ions. As the positive electrode active material, a material that can be used as a positive electrode active material for a lithium ion secondary battery, such as a lithium composite metal oxide having a layered rock salt structure, a metal oxide having a spinel structure, and a polyanionic compound, may be adopted. Further, two or more kinds of positive electrode active materials may be used in combination. In the present embodiment, the positive electrode active material layer 22 contains olivine-type lithium iron phosphate (LiFePO 4 ) as a composite active material.

負極活物質層２３は、リチウムイオン等の電荷担体を吸蔵及び放出可能である単体、合金、又は、炭素、金属化合物、リチウムと合金化可能な元素もしくはその化合物等が挙げられる。炭素としては天然黒鉛、人造黒鉛、あるいはハードカーボン（難黒鉛化性炭素）又はソフトカーボン（易黒鉛化性炭素）が挙げられる。人造黒鉛としては、高配向性グラファイト、メソカーボンマイクロビーズ等が挙げられる。リチウムと合金化可能な元素の例としては、シリコン（ケイ素）及びスズが挙げられる。本実施形態において、負極活物質層２３は炭素系材料としての黒鉛を含む。 Examples of the negative electrode active material layer 23 include simple substances, alloys, carbon, metal compounds, elements that can be alloyed with lithium, or compounds thereof, which can occlude and release charge carriers such as lithium ions. Examples of carbon include natural graphite, artificial graphite, hard carbon (non-graphitizable carbon) or soft carbon (easy graphitizable carbon). Examples of artificial graphite include highly oriented graphite and mesocarbon microbeads. Examples of elements that can be alloyed with lithium include silicon and tin. In the present embodiment, the negative electrode active material layer 23 contains graphite as a carbon-based material.

正極活物質層２２及び負極活物質層２３のそれぞれは、必要に応じて電気伝導性を高めるための導電助材、結着剤、電解質（ポリマーマトリクス、イオン伝導性ポリマー、電解液等）、イオン伝導性を高めるための電解質支持塩（リチウム塩）等をさらに含み得る。活物質層に含まれる成分又は成分の配合比及び活物質層の厚さは特に限定されず、リチウムイオン二次電池についての公知の知見が適宜参照され得る。活物質層の厚みは、例えば２μｍ～１５０μｍである。第１集電体２０及び第２集電体２１の表面に活物質層を形成させるために、ロールコート法等の公知の方法を用いてもよい。正極１１又は負極１２の熱安定性を向上させるために、第１集電体２０及び第２集電体２１の表面（片面又は両面）又は正極活物質層２２及び負極活物質層２３の表面に耐熱層を設けてもよい。耐熱層は、例えば、無機粒子と結着剤とを含み、その他に増粘剤等の添加剤を含んでもよい。 Each of the positive electrode active material layer 22 and the negative electrode active material layer 23 has a conductive auxiliary material, a binder, an electrolyte (polymer matrix, ionic conductive polymer, electrolytic solution, etc.) and ions for enhancing electrical conductivity as needed. It may further contain an electrolyte-supporting salt (lithium salt) or the like for enhancing conductivity. The components contained in the active material layer or the compounding ratio of the components and the thickness of the active material layer are not particularly limited, and known knowledge about the lithium ion secondary battery can be appropriately referred to. The thickness of the active material layer is, for example, 2 μm to 150 μm. In order to form an active material layer on the surfaces of the first current collector 20 and the second current collector 21, a known method such as a roll coating method may be used. In order to improve the thermal stability of the positive electrode 11 or the negative electrode 12, on the surface (one side or both sides) of the first current collector 20 and the second current collector 21 or on the surface of the positive electrode active material layer 22 and the negative electrode active material layer 23. A heat-resistant layer may be provided. The heat-resistant layer may contain, for example, inorganic particles and a binder, and may also contain an additive such as a thickener.

導電助剤は、正極１１又は負極１２の導電性を高めるために添付される。導電助剤は、例えば、アセチレンブラック、カーボンブラック、グラファイト等である。
結着剤としては、ポリフッ化ビニリデン、ポリテトラフルオロエチレン、フッ化ゴム等の含フッ素樹脂、ポリプロピレン、ポリエチレン等の熱可塑性樹脂、ポリイミド、ポリアミド等のイミド系樹脂、アルコキシシリル基含有樹脂、ポリ（メタ）アクリル酸等のアクリル系樹脂、スチレン―ブタジエンゴム（ＳＢＲ）、カルボキシメチルセルロース、アルギン酸ナトリウム、アルギン酸アンモニウム等のアルギン酸塩、水溶性セルロースエステル架橋体、デンプン―アクリル酸グラフト重合体が挙げられる。これらの結着剤は、単独で又は複数で用いられ得る。溶媒としては、例えば、水、Ｎ―メチル―２―ピロドリン（ＮＭＰ）等が用いられる。 The conductive auxiliary agent is attached to increase the conductivity of the positive electrode 11 or the negative electrode 12. The conductive auxiliary agent is, for example, acetylene black, carbon black, graphite or the like.
Examples of the binder include fluororesins such as polyvinylidene fluoride, polytetrafluoroethylene and rubber fluoride, thermoplastic resins such as polypropylene and polyethylene, imide-based resins such as polyimide and polyamide, resins containing an alkoxysilyl group, and poly (poly). Examples thereof include acrylic resins such as meth) acrylic acid, styrene-butadiene rubber (SBR), carboxymethyl cellulose, sodium alginate, arginate such as ammonium alginate, water-soluble cellulose ester cross-linked products, and starch-acrylic acid graft polymers. These binders can be used alone or in combination. As the solvent, for example, water, N-methyl-2-pyrodrin (NMP) and the like are used.

セパレータ１３は、正極１１と負極１２との間に配置されている。セパレータ１３は、正極１１と負極１２とを隔離することで両極の接触による短絡を防止しつつ、リチウムイオン等の電荷担体を通過させる。 The separator 13 is arranged between the positive electrode 11 and the negative electrode 12. The separator 13 separates the positive electrode 11 and the negative electrode 12 to prevent a short circuit due to contact between the two electrodes, and allows a charge carrier such as lithium ion to pass therethrough.

セパレータ１３は、例えば、電解質を吸収保持するポリマーを含む多孔性シート又は不織布であってもよい。セパレータ１３を構成する材料としては、例えば、ポリプロピレン、ポリエチレン、ポリオレフィン、ポリエステル等が挙げられる。セパレータ１３は、単層構造又は多層構造を有してもよい。多層構造は、例えば、接着層、耐熱層としてのセラミック層等を有してもよい。セパレータ１３には、電解質が含浸されてもよく、セパレータ１３自体を高分子ゲル電解質又は電解質等の電解質で構成してもよい。 The separator 13 may be, for example, a porous sheet or a non-woven fabric containing a polymer that absorbs and retains an electrolyte. Examples of the material constituting the separator 13 include polypropylene, polyethylene, polyolefin, polyester and the like. The separator 13 may have a single-layer structure or a multi-layer structure. The multilayer structure may have, for example, an adhesive layer, a ceramic layer as a heat-resistant layer, and the like. The separator 13 may be impregnated with an electrolyte, or the separator 13 itself may be composed of a polymer gel electrolyte or an electrolyte such as an electrolyte.

セパレータ１３に含浸される電解質としては、例えば、非水溶媒と非水溶媒に溶解した電解質塩とを含む液体電解質（電解液）、又はポリマーマトリックス中に保持された電解質を含む高分子ゲル電解質等が挙げられる。 Examples of the electrolyte impregnated in the separator 13 include a liquid electrolyte (electrolyte solution) containing a non-aqueous solvent and an electrolyte salt dissolved in the non-aqueous solvent, a polymer gel electrolyte containing an electrolyte held in a polymer matrix, and the like. Can be mentioned.

セパレータ１３に電解液が含浸される場合、その電解質塩として、ＬｉＣｌＯ４、ＬｉＡｓＦ６ＬｉＰＦ６、ＬｉＢＦ４、ＬｉＣＦ３ＳＯ３、ＬｉＮ（ＦＳＯ２）２、ＬｉＮ（ＣＦ３ＳＯ２）２、等の公知のリチウム塩を使用できる。また、非水溶媒として、環状カーボネート類、環状エステル類、鎖状カーボネート類、鎖状エステル類、エーテル類等の公知の溶媒を使用できる。なお、これら公知の溶媒材料を二種以上組み合わせて用いてもよい。 When the separator 13 is impregnated with an electrolytic solution, the electrolyte salts thereof include LiClO 4 , LiAsF 6 LiPF 6 , LiBF 4 , LiCF 3 SO 3 , LiN (FSO 2 ) 2 , LiN (CF 3 SO 2 ) 2 , and the like. Known lithium salts can be used. Further, as the non-aqueous solvent, known solvents such as cyclic carbonates, cyclic esters, chain carbonates, chain esters, ethers and the like can be used. In addition, you may use two or more kinds of these known solvent materials in combination.

シール部材１４は、第１集電体２０と第２集電体２１との間に位置する。シール部材１４は、第１集電体２０及び第２集電体２１に溶着される。シール部材１４は、絶縁材料を含み、第１集電体２０と第２集電体２１との間を絶縁することによって短絡を防止する。本実施形態では、シール部材１４の材料は酸変性ポリエチレンである。なお、シール部材１４の材料は、酸変性ポリプロピレンであってもよい。 The seal member 14 is located between the first current collector 20 and the second current collector 21. The seal member 14 is welded to the first current collector 20 and the second current collector 21. The sealing member 14 contains an insulating material and prevents a short circuit by insulating between the first current collector 20 and the second current collector 21. In this embodiment, the material of the sealing member 14 is acid-modified polyethylene. The material of the sealing member 14 may be acid-modified polypropylene.

シール部材１４は、第１集電体２０の縁部２０ｅ及び第２集電体２１の縁部２１ｅに沿って延在する。積層方向Ｄに沿って外側から蓄電セル１０を見た平面視において、シール部材１４は、正極活物質層２２の周囲を取り囲む矩形枠状である。積層方向Ｄにおけるシール部材１４と第１集電体２０との間に、セパレータ１３の縁部が挟み込まれている。 The seal member 14 extends along the edge portion 20e of the first current collector 20 and the edge portion 21e of the second current collector 21. In a plan view of the storage cell 10 viewed from the outside along the stacking direction D, the seal member 14 has a rectangular frame shape that surrounds the periphery of the positive electrode active material layer 22. The edge portion of the separator 13 is sandwiched between the seal member 14 and the first current collector 20 in the stacking direction D.

シール部材１４は、正極１１と負極１２とシール部材１４とによって画定される空間Ｓを封止する。シール部材１４は、空間Ｓに収容された電解液の外部への透過を抑制する。また、シール部材１４は、外部から空間Ｓ内への水分の侵入を抑制する。本実施形態では、各蓄電セル１０に配置されるシール部材１４は、積層方向Ｄにおける第１集電体２０と第２集電体２１との間に配置される部分と、第１集電体２０の縁部２０ｅ及び第２集電体２１の縁部２１ｅよりも外側に延びる部分と、を有する。これにより、積層方向Ｄに隣り合うシール部材１４の外側に延びる部分同士が接合されて一体化している。蓄電セル１０は、複数のシール部材１４が一体化された封止体１４ａを有する。 The seal member 14 seals the space S defined by the positive electrode 11, the negative electrode 12, and the seal member 14. The sealing member 14 suppresses the permeation of the electrolytic solution contained in the space S to the outside. Further, the seal member 14 suppresses the intrusion of moisture from the outside into the space S. In the present embodiment, the seal member 14 arranged in each storage cell 10 is a portion arranged between the first current collector 20 and the second current collector 21 in the stacking direction D, and the first current collector. It has an edge portion 20e of 20 and a portion extending outward from the edge portion 21e of the second current collector 21. As a result, the portions extending to the outside of the seal members 14 adjacent to each other in the stacking direction D are joined and integrated. The storage cell 10 has a sealing body 14a in which a plurality of sealing members 14 are integrated.

図２、図３又は図４に示すように、筒部材３０を軸方向に沿って外側から見た軸方向視において、筒部材３０は偏平形状である。筒部材３０の軸方向視において偏平の長手が延びる方向を第１延在方向Ａとし、第１延在方向Ａと直交する方向を第２延在方向Ｂとする。第２延在方向Ｂは積層方向Ｄと同じ方向である。第１延在方向Ａへの筒部材３０の寸法は、第２延在方向Ｂへの筒部材３０の寸法より長い。 As shown in FIGS. 2, 3 or 4, the tubular member 30 has a flat shape when viewed from the outside along the axial direction. The direction in which the length of the flat surface extends in the axial direction of the tubular member 30 is referred to as the first extending direction A, and the direction orthogonal to the first extending direction A is referred to as the second extending direction B. The second extending direction B is the same direction as the stacking direction D. The dimension of the tubular member 30 in the first extending direction A is longer than the dimension of the tubular member 30 in the second extending direction B.

筒部材３０は、通路３１と、閉塞部３２と、を有する。筒部材３０の軸方向における、空間Ｓの外部寄りの第１端部３０ａは、シール部材１４の外側の端面１４１よりも外側に位置する。筒部材３０の第１端部３０ａは、閉塞部３２によって閉塞されている。なお、閉塞部３２は、筒部材３０の第１端部３０ａが熱によって溶着されることにより形成されている。閉塞部３２は、シール部材１４よりも外部寄りにおいて通路３１を閉塞している。筒部材３０の軸方向における、第１端部３０ａと反対側の第２端部３０ｂは、シール部材１４の内側の端面１４０よりも内側に位置する。筒部材３０の第２端部３０ｂは、空間Ｓに向けて開口している。通路３１は、閉塞部３２から空間Ｓの内部に向かってシール部材１４を第１延在方向Ａ及び第２延在方向Ｂ（積層方向Ｄ）と交差する方向である筒部材３０の軸方向Ｘに貫通して設けられている。すなわち、通路３１は、筒部材３０の軸方向に沿って延びている。 The tubular member 30 has a passage 31 and a closing portion 32. The first end portion 30a of the space S near the outside in the axial direction of the tubular member 30 is located outside the outer end surface 141 of the seal member 14. The first end portion 30a of the tubular member 30 is closed by the closing portion 32. The closing portion 32 is formed by welding the first end portion 30a of the tubular member 30 by heat. The closing portion 32 closes the passage 31 closer to the outside than the sealing member 14. The second end portion 30b opposite to the first end portion 30a in the axial direction of the tubular member 30 is located inside the inner end surface 140 of the seal member 14. The second end portion 30b of the tubular member 30 is open toward the space S. In the passage 31, the axial direction X of the tubular member 30 which is the direction in which the seal member 14 intersects the first extending direction A and the second extending direction B (stacking direction D) from the closing portion 32 toward the inside of the space S. It is provided through the space. That is, the passage 31 extends along the axial direction of the tubular member 30.

筒部材３０の第２端部３０ｂ寄りの一部分は、積層方向Ｄにおける第２集電体２１と第１集電体２０との間に位置する。したがって、筒部材３０の第２端部３０ｂ寄りの一部は、積層方向Ｄから見て第１集電体２０及び第２集電体２１と重なり合う。筒部材３０の第２端部３０ｂは、シール部材１４の内周面において開口している。積層方向Ｄに沿って外側から蓄電セル１０を見た平面視において、筒部材３０の第１端部３０ａ寄りの残りの部分は、蓄電セル１０の外部に位置している。 A part of the tubular member 30 near the second end portion 30b is located between the second current collector 21 and the first current collector 20 in the stacking direction D. Therefore, a part of the tubular member 30 near the second end portion 30b overlaps with the first current collector 20 and the second current collector 21 when viewed from the stacking direction D. The second end portion 30b of the tubular member 30 is open on the inner peripheral surface of the sealing member 14. In a plan view of the storage cell 10 viewed from the outside along the stacking direction D, the remaining portion of the tubular member 30 near the first end portion 30a is located outside the storage cell 10.

蓄電セル１０は、積層方向Ｄにおける筒部材３０と第２集電体２１との間に溶着補助部材４０を有する。蓄電セル１０は軸方向視において筒部材３０を取り囲む態様に溶着補助部材４０を有していてもよい。溶着補助部材４０は、筒部材３０とシール部材１４との間に介在する。シール部材１４と溶着補助部材４０は互いに溶着している。溶着補助部材４０の材料は、シール部材１４の材料と同じであるのが好ましい。したがって、シール部材１４の材料が酸変性ポリエチレンであれば、溶着補助部材４０の材料は酸変性ポリエチレンが用いられ、シール部材１４の材料が酸変性ポリプロピレンであれば、溶着補助部材４０の材料は、酸変性ポリプロピレンが用いられる。 The storage cell 10 has a welding assisting member 40 between the tubular member 30 and the second current collector 21 in the stacking direction D. The storage cell 10 may have a welding assisting member 40 in a manner surrounding the tubular member 30 in the axial direction. The welding assist member 40 is interposed between the tubular member 30 and the seal member 14. The seal member 14 and the welding auxiliary member 40 are welded to each other. The material of the welding auxiliary member 40 is preferably the same as the material of the sealing member 14. Therefore, if the material of the sealing member 14 is acid-modified polyethylene, the material of the welding auxiliary member 40 is acid-modified polyethylene, and if the material of the sealing member 14 is acid-modified polypropylene, the material of the welding auxiliary member 40 is. Acid-modified polypropylene is used.

図４又は図５に示すように、溶着補助部材４０を軸方向Ｘに沿って外側から見た軸方向視において、溶着補助部材４０は偏平形状である。溶着補助部材４０の軸方向視において、筒部材３０の第１延在方向Ａと同じ方向を第１方向Ｙとし、第１方向Ｙに直交する方向を第２方向Ｚとする。第２方向Ｚは、積層方向Ｄと同じ方向である。第１方向Ｙへの溶着補助部材４０の寸法は、第２方向Ｚへの溶着補助部材４０の寸法より長い。 As shown in FIG. 4 or 5, the welding assisting member 40 has a flat shape when viewed from the outside along the axial direction X. In the axial view of the welding assist member 40, the same direction as the first extending direction A of the tubular member 30 is defined as the first direction Y, and the direction orthogonal to the first direction Y is defined as the second direction Z. The second direction Z is the same direction as the stacking direction D. The dimension of the welding assisting member 40 in the first direction Y is longer than the dimension of the welding assisting member 40 in the second direction Z.

溶着補助部材４０は、第１方向Ｙにおいて筒部材３０の外面から突出する突出部４１を有する。なお、溶着補助部材４０は、軸方向視において筒部材３０の外面に沿う延在部４２を有する。延在部４２は、第２方向Ｚに筒部材３０を挟む部位である。突出部４１は、延在部４２の第１方向Ｙ両側から突出する部位である。第１方向Ｙにおける突出部４１の寸法Ｌ１は、空間Ｓの内部から外部に近づくに従い長くなっている。つまり、蓄電セル１０を積層方向Ｄの外側から見た平面視において、溶着補助部材４０は、突出部４１の第１方向Ｙの先端に傾斜している部分を有する。したがって、第１方向Ｙにおける溶着補助部材４０とシール部材１４との界面は、上記平面視において軸方向Ｘに対して傾斜しているといえる。 The welding assisting member 40 has a protruding portion 41 protruding from the outer surface of the tubular member 30 in the first direction Y. The welding assisting member 40 has an extending portion 42 along the outer surface of the tubular member 30 in the axial direction. The extending portion 42 is a portion that sandwiches the tubular member 30 in the second direction Z. The protruding portion 41 is a portion of the extending portion 42 that protrudes from both sides in the first direction Y. The dimension L1 of the protrusion 41 in the first direction Y becomes longer as it approaches the outside from the inside of the space S. That is, when the power storage cell 10 is viewed from the outside in the stacking direction D, the welding assisting member 40 has a portion inclined to the tip of the protrusion 41 in the first direction Y. Therefore, it can be said that the interface between the welding assisting member 40 and the sealing member 14 in the first direction Y is inclined with respect to the axial direction X in the plan view.

図示しないが、溶着補助部材４０は、帯状の前駆体を加熱して形成されている。帯状の前駆体の両端を溶着して無端状にするとともに、前駆体を筒部材３０の外面に溶着して一体化した状態とする。そして、前駆体を第２集電体２１の第１面２１ａに載せ、第２集電体２１と第１集電体２０との間にシール部材１４を介在させた状態で第１集電体２０及び第２集電体２１とシール部材１４とを溶着する際、前駆体の内面は筒部材３０に溶着される。また、前駆体の外面のうち、第２集電体２１の第１面２１ａに対面する部分は第１面２１ａに溶着され、その他の部位はシール部材１４に溶着される。 Although not shown, the welding assist member 40 is formed by heating a strip-shaped precursor. Both ends of the strip-shaped precursor are welded to form an endless shape, and the precursor is welded to the outer surface of the tubular member 30 to be integrated. Then, the precursor is placed on the first surface 21a of the second current collector 21, and the first current collector 14 is interposed between the second current collector 21 and the first current collector 20. When the 20 and the second current collector 21 and the seal member 14 are welded, the inner surface of the precursor is welded to the tubular member 30. Further, of the outer surface of the precursor, the portion of the second current collector 21 facing the first surface 21a is welded to the first surface 21a, and the other portions are welded to the sealing member 14.

したがって、一対の延在部４２の内面は筒部材３０の外面に溶着されている。一対の延在部４２のうち、第２集電体２１の第１面２１ａに対面する一方の延在部４２の外面は第２集電体２１に溶着され、他方の延在部４２の外面はシール部材１４に溶着されている。また、突出部４１において第２方向Ｚに対面する部分は互いに溶着されている。突出部４１において、第２集電体２１の第１面２１ａに対面する外面は第２集電体２１に溶着され、その他の外面はシール部材１４に溶着されている。また、第１方向Ｙにおける突出部４１の外面もシール部材１４に溶着されている。溶着補助部材４０は、筒部材３０と、被溶着集電体としての第２集電体２１と、の間において、筒部材３０に密着し、かつ第２集電体２１に溶着している。 Therefore, the inner surface of the pair of extending portions 42 is welded to the outer surface of the tubular member 30. Of the pair of extending portions 42, the outer surface of one extending portion 42 facing the first surface 21a of the second current collector 21 is welded to the second current collector 21, and the outer surface of the other extending portion 42 is welded. Is welded to the seal member 14. Further, the portions of the protruding portion 41 facing the second direction Z are welded to each other. In the protruding portion 41, the outer surface of the second current collector 21 facing the first surface 21a is welded to the second current collector 21, and the other outer surfaces are welded to the seal member 14. Further, the outer surface of the protrusion 41 in the first direction Y is also welded to the seal member 14. The welding auxiliary member 40 is in close contact with the cylinder member 30 and welded to the second current collector 21 between the cylinder member 30 and the second current collector 21 as a welded current collector.

溶着補助部材４０は、軸方向Ｘにおいて、筒部材３０の第１端部３０ａと第２端部３０ｂとの間に配置されており、シール部材１４の内側の端面１４０から、第２集電体２１の外側の端面２１０にわたって配置されている。筒部材３０及び溶着補助部材４０を配置した箇所における蓄電セル１０の積層方向Ｄの寸法を寸法Ｌ２とする。寸法Ｌ２は、第１集電体２０の最外面２００から第２集電体２１の最外面２１１までの長さを指す。寸法Ｌ２は、筒部材３０及び溶着補助部材４０を配置していない箇所よりも厚くなっている。 The welding assist member 40 is arranged between the first end portion 30a and the second end portion 30b of the tubular member 30 in the axial direction X, and is a second current collector from the inner end surface 140 of the seal member 14. It is arranged over the outer end face 210 of 21. The dimension L2 is the dimension of the storage cell 10 in the stacking direction D at the position where the tubular member 30 and the welding assist member 40 are arranged. The dimension L2 refers to the length from the outermost surface 200 of the first current collector 20 to the outermost surface 211 of the second current collector 21. The dimension L2 is thicker than the portion where the tubular member 30 and the welding assist member 40 are not arranged.

第２延在方向Ｂの筒部材３０の寸法と、第２方向Ｚへの溶着補助部材４０の寸法との和を、積層寸法Ｌ３とする。また、シール部材１４において、筒部材３０及び溶着補助部材４０を配置していない箇所における積層方向Ｄの寸法をシール寸法Ｌ４とする。寸法Ｌ２は、積層寸法Ｌ３とシール寸法Ｌ４の和である。 The sum of the dimension of the tubular member 30 in the second extending direction B and the dimension of the welding assisting member 40 in the second direction Z is defined as the laminated dimension L3. Further, in the seal member 14, the dimension of the stacking direction D at the place where the tubular member 30 and the welding assist member 40 are not arranged is defined as the seal dimension L4. The dimension L2 is the sum of the laminated dimension L3 and the seal dimension L4.

本実施形態では、筒部材３０は、電解液を注入するために用いられる。筒部材３０は、通路３１と、閉塞部３２と、を有している。通路３１は、周壁３１ａにより形成されている。閉塞部３２は、通路３１の第１端部３０ａの開口を閉塞する。 In this embodiment, the tubular member 30 is used for injecting an electrolytic solution. The tubular member 30 has a passage 31 and a closing portion 32. The passage 31 is formed by a peripheral wall 31a. The closing portion 32 closes the opening of the first end portion 30a of the passage 31.

次に、本実施形態の作用について説明する。
蓄電セル１０は、溶着補助部材４０を備える。溶着補助部材４０と第２集電体２１とが溶着されて溶着補助部材４０と第２集電体２１とが密着している。また、溶着補助部材４０は、筒部材３０とシール部材１４との間に介在するとともにシール部材１４に溶着している。 Next, the operation of this embodiment will be described.
The storage cell 10 includes a welding assisting member 40. The welding assisting member 40 and the second current collector 21 are welded together, and the welding assisting member 40 and the second current collector 21 are in close contact with each other. Further, the welding auxiliary member 40 is interposed between the tubular member 30 and the seal member 14 and is welded to the seal member 14.

本実施形態では、以下の効果を得ることができる。
（１）蓄電セル１０は、溶着補助部材４０を備えるため、溶着補助部材４０と第２集電体２１とが溶着され、溶着補助部材４０と第２集電体２１とが密着する。したがって、第２集電体２１に対し、溶着補助部材４０を介して筒部材３０を接合した構成において、当該接合箇所のシール性が低下せず、蓄電セル１０のシール性の低下を抑制することができる。 In this embodiment, the following effects can be obtained.
(1) Since the power storage cell 10 includes a welding assisting member 40, the welding assisting member 40 and the second current collector 21 are welded together, and the welding assisting member 40 and the second current collector 21 are in close contact with each other. Therefore, in the configuration in which the tubular member 30 is joined to the second current collector 21 via the welding assist member 40, the sealing property of the joined portion is not deteriorated, and the deterioration of the sealing property of the storage cell 10 is suppressed. Can be done.

（２）溶着補助部材４０は、筒部材３０を囲むとともに、筒部材３０とシール部材１４との間に介在する。そして、溶着補助部材４０の外面はシール部材１４にも溶着している。このため、溶着補助部材４０とシール部材１４とが密着する。その結果、溶着補助部材４０とシール部材１４との間のシール性の低下を抑制できる。 (2) The welding auxiliary member 40 surrounds the tubular member 30 and is interposed between the tubular member 30 and the seal member 14. The outer surface of the welding assisting member 40 is also welded to the sealing member 14. Therefore, the welding assist member 40 and the seal member 14 are in close contact with each other. As a result, deterioration of the sealing property between the welding assist member 40 and the sealing member 14 can be suppressed.

（３）溶着補助部材４０の材料は、シール部材１４の材料と同じであるため、シール部材１４と溶着補助部材４０とをより溶着させ易くすることができ、シール部材１４の材料と溶着補助部材４０の材料とが異なる場合に比べてシール部材１４と溶着補助部材４０とを密着させ易くすることができる。したがって、蓄電セル１０のシール性の低下をさらに抑制することができる。 (3) Since the material of the welding assisting member 40 is the same as the material of the sealing member 14, the sealing member 14 and the welding assisting member 40 can be more easily welded, and the material of the sealing member 14 and the welding assisting member can be easily welded. Compared with the case where the material of 40 is different, the sealing member 14 and the welding assisting member 40 can be easily brought into close contact with each other. Therefore, it is possible to further suppress the deterioration of the sealing property of the storage cell 10.

（４）筒部材３０は、通路３１と、閉塞部３２と、を有する。閉塞部３２により、通路３１を通じて電解液が空間Ｓの内部から外部へ漏れ出ることを防止できる。
（５）溶着補助部材４０は、第１方向Ｙにおいて筒部材３０から突出する突出部４１を有し、第１方向Ｙへの突出部４１の形状は、突出部４１の寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い長くなる形状である。例えば、蓄電セル１０の内圧が溶着補助部材４０に作用すると、溶着補助部材４０が、蓄電セル１０の外部に向けて押圧される。突出部４１の寸法が軸方向Ｘに沿って変化する形状であることにより、溶着補助部材４０とシール部材１４との界面での応力集中を緩和することができる。したがって、溶着補助部材４０とシール部材１４との界面が裂けることを抑制することができる。 (4) The tubular member 30 has a passage 31 and a closing portion 32. The closing portion 32 can prevent the electrolytic solution from leaking from the inside of the space S to the outside through the passage 31.
(5) The welding auxiliary member 40 has a protruding portion 41 protruding from the tubular member 30 in the first direction Y, and the shape of the protruding portion 41 in the first direction Y is such that the dimension of the protruding portion 41 is the axial direction X. It has a shape that becomes longer as it approaches the outside from the inside of the space S along the space S. For example, when the internal pressure of the storage cell 10 acts on the welding assisting member 40, the welding assisting member 40 is pressed toward the outside of the storage cell 10. Since the dimension of the protrusion 41 changes along the axial direction X, stress concentration at the interface between the welding assist member 40 and the seal member 14 can be relaxed. Therefore, it is possible to prevent the interface between the welding assist member 40 and the seal member 14 from being torn.

なお、上記実施形態は、以下のように変更して実施することができる。上記実施形態及び以下の変更例は、技術的に矛盾しない範囲で互いに組み合わせて実施することができる。 The above embodiment can be modified and implemented as follows. The above embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

○ 図６に示すように、シール部材１４は、積層方向Ｄにおいて筒部材３０と重なる位置に、積層方向Ｄに沿って第２集電体２１から離れるように凹む凹部４３を有してもよい。積層方向Ｄにおける凹部４３の寸法は、第２延在方向Ｂの筒部材３０の寸法と、第２方向Ｚへの溶着補助部材４０の寸法との和と同じである。第２方向Ｚへの溶着補助部材４０の寸法は、第２方向Ｚにおける筒部材３０の両側に位置する延在部４２の第２方向Ｚへの寸法である。これにより、積層方向Ｄへの凹部４３の寸法の分だけ蓄電セル１０の厚みが厚くなることを抑制することができる。また、蓄電セル１０は、積層方向Ｄに筒部材３０及び溶着補助部材４０が重なる位置が局所的に厚くなることを抑制することができる。なお、積層方向Ｄへの凹部４３の寸法は、特に限定されるものではなく、積層方向Ｄへの筒部材３０の寸法と積層方向Ｄへの溶着補助部材４０の寸法との和以上であってもよいし、それ以下であってもよい。例えば、積層方向Ｄへの凹部４３の寸法は、第２延在方向Ｂへの筒部材３０の寸法と同じにしてもよい。 ○ As shown in FIG. 6, the seal member 14 may have a recess 43 recessed along the stacking direction D so as to be separated from the second current collector 21 at a position overlapping the tubular member 30 in the stacking direction D. .. The dimension of the recess 43 in the stacking direction D is the same as the sum of the dimension of the tubular member 30 in the second extending direction B and the dimension of the welding auxiliary member 40 in the second direction Z. The dimension of the welding assisting member 40 in the second direction Z is the dimension of the extending portions 42 located on both sides of the tubular member 30 in the second direction Z in the second direction Z. As a result, it is possible to prevent the storage cell 10 from becoming thicker by the size of the recess 43 in the stacking direction D. Further, the storage cell 10 can prevent the position where the tubular member 30 and the welding assist member 40 overlap in the stacking direction D from becoming thick locally. The size of the recess 43 in the stacking direction D is not particularly limited, and is equal to or greater than the sum of the size of the tubular member 30 in the stacking direction D and the size of the welding assisting member 40 in the stacking direction D. It may be less than that. For example, the dimension of the recess 43 in the stacking direction D may be the same as the dimension of the tubular member 30 in the second extending direction B.

○ 凹部４３を有する一体のシール部材１４を用いる必要はなく、積層方向Ｄへの寸法が異なる複数のシール部材を用いることによって、凹部４３を有するシール部材１４としてもよい。 ○ It is not necessary to use the integrated seal member 14 having the recess 43, and the seal member 14 having the recess 43 may be used by using a plurality of seal members having different dimensions in the stacking direction D.

○ 実施形態において、溶着補助部材４０の突出部４１の形状は、突出部４１の第１方向Ｙへの寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い長くなるように、蓄電セル１０を積層方向Ｄの外側から見た平面視において傾斜する形状であったが、これに限らない。例えば、突出部４１の第１方向Ｙへの寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い短くなるように、蓄電セル１０を積層方向Ｄの外側から見た平面視において傾斜する形状であってもよい。また、突出部４１の第１方向Ｙへの寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い短くなるように、蓄電セル１０を積層方向Ｄの外側から見た平面視において湾曲する形状であってもよい。さらに、突出部４１の第１方向Ｙへの寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い変化するように、蓄電セル１０を積層方向Ｄの外側から見た平面視において複数回傾斜する形状であってもよい。要は、突出部４１の形状は、突出部４１の第１方向Ｙへの寸法が軸方向Ｘに沿って空間Ｓの内部から外部に近づくに従い変化する形状であればよい。 ○ In the embodiment, the shape of the protrusion 41 of the welding assist member 40 is stored so that the dimension of the protrusion 41 in the first direction Y becomes longer as the dimension of the protrusion 41 approaches the outside from the inside of the space S along the axial direction X. The cell 10 has a shape that is inclined in a plan view when viewed from the outside in the stacking direction D, but the shape is not limited to this. For example, the storage cell 10 is tilted in a plan view from the outside of the stacking direction D so that the dimension of the protrusion 41 in the first direction Y becomes shorter as it approaches the outside from the inside of the space S along the axial direction X. It may have a shape to be used. Further, the storage cell 10 is curved in a plan view from the outside of the stacking direction D so that the dimension of the protrusion 41 in the first direction Y becomes shorter as it approaches the outside from the inside of the space S along the axial direction X. It may have a shape to be used. Further, a plurality of storage cells 10 are arranged in a plan view from the outside of the stacking direction D so that the dimension of the protrusion 41 in the first direction Y changes from the inside of the space S toward the outside along the axial direction X. It may have a shape that can be tilted. In short, the shape of the protruding portion 41 may be a shape in which the dimension of the protruding portion 41 in the first direction Y changes from the inside to the outside of the space S along the axial direction X.

○ 溶着補助部材４０は突出部４１を有さなくてもよい。この場合、溶着補助部材４０は筒部材３０を覆う程度に設けられていればよい。
○ 実施形態において、シール部材１４に、セパレータ１３の縁部１３ａが埋設されていてもよい。 ○ The welding assist member 40 does not have to have the protrusion 41. In this case, the welding assist member 40 may be provided so as to cover the tubular member 30.
○ In the embodiment, the edge portion 13a of the separator 13 may be embedded in the seal member 14.

○ 実施形態において、第２集電体２１が、溶着補助部材４０が溶着される被溶着集電体であったが、第１集電体２０が、溶着補助部材４０が溶着される被溶着集電体であってもよい。 ○ In the embodiment, the second current collector 21 is a welded current collector to which the welding assisting member 40 is welded, but the first current collecting body 20 is a welded collecting body to which the welding assisting member 40 is welded. It may be an electric body.

○ 実施形態において、筒部材３０は、電解液を注入するために用いられたが、空間Ｓの内部から外部へ気体を排出するためにも用いられてもよい。
○ 溶着補助部材４０は、筒部材３０を囲んでおらず、シール部材１４に溶着されていなくてもよい。具体的には、溶着補助部材４０は、積層方向Ｄにおける筒部材３０と被接合集電体との間のみに位置していてもよい。この場合、筒部材３０の外面のうち、被接合集電体寄りの外面は溶着補助部材４０に溶着される。また、筒部材３０の外面のうち、溶着補助部材４０に溶着されていない外面は、シール部材１４に溶着される。 ○ In the embodiment, the tubular member 30 is used for injecting the electrolytic solution, but may also be used for discharging the gas from the inside of the space S to the outside.
○ The welding assisting member 40 does not surround the tubular member 30, and may not be welded to the sealing member 14. Specifically, the welding auxiliary member 40 may be located only between the tubular member 30 and the current collector to be joined in the stacking direction D. In this case, of the outer surface of the tubular member 30, the outer surface closer to the current collector to be welded is welded to the welding assist member 40. Further, of the outer surface of the tubular member 30, the outer surface that is not welded to the welding auxiliary member 40 is welded to the seal member 14.

○ 溶着補助部材４０は、シール部材１４の内側の端面１４０からシール部材１４の外側の端面１４１にわたって設けられていてもよい。
○ 実施形態において、筒部材３０の通路３１は、シール部材１４を貫通する長さに形成されているが、シール部材１４を貫通しない長さに形成されていてもよい。例えば、シール部材１４の外側の端面１４１と、筒部材３０の第１端部３０ａ（閉塞部３２の外側の端面）とが一致するように形成され、通路３１はシール部材１４の途中まで貫通するように形成されていてもよい。この場合も、筒部材３０は、シール部材１４を貫通して延びているとともに、通路３１は、筒部材３０の軸方向Ｘに沿って延びている。 ○ The welding assist member 40 may be provided from the inner end surface 140 of the seal member 14 to the outer end surface 141 of the seal member 14.
○ In the embodiment, the passage 31 of the tubular member 30 is formed to have a length that penetrates the seal member 14, but may be formed to have a length that does not penetrate the seal member 14. For example, the outer end surface 141 of the seal member 14 and the first end portion 30a of the tubular member 30 (the outer end surface of the closing portion 32) are formed so as to coincide with each other, and the passage 31 penetrates halfway through the seal member 14. It may be formed as follows. Also in this case, the tubular member 30 extends through the seal member 14, and the passage 31 extends along the axial direction X of the tubular member 30.

１…蓄電装置、１０…蓄電セル、１１…正極、１２…負極、１４…シール部材、１５…、２０…第１集電体、２１…第２集電体、３０…筒部材、３１…通路、３２…閉塞部、４０…溶着補助部材、４１…突出部、４３…凹部、Ｄ…積層方向、Ｌ１…寸法、Ｌ２…寸法、Ｌ３…寸法、Ｌ４…寸法、Ｓ…空間、Ｘ…軸方向、Ｙ…第１方向。 1 ... power storage device, 10 ... power storage cell, 11 ... positive electrode, 12 ... negative electrode, 14 ... seal member, 15 ..., 20 ... first current collector, 21 ... second collector, 30 ... cylinder member, 31 ... passage , 32 ... Closure part, 40 ... Welding auxiliary member, 41 ... Projection part, 43 ... Recession, D ... Lamination direction, L1 ... Dimension, L2 ... Dimension, L3 ... Dimension, L4 ... Dimension, S ... Space, X ... Axial direction , Y ... First direction.

Claims (8)

第１集電体を有する正極と、
第２集電体を有する負極と、
前記正極と前記負極とが重なり合う積層方向において前記第１集電体及び前記第２集電体に溶着するシール部材と、
前記シール部材を貫通して延びる筒部材と、
前記積層方向における前記筒部材と、前記第１集電体及び前記第２集電体のいずれか一方の被溶着集電体と、の間において、前記筒部材に密着し、かつ前記被溶着集電体に溶着している溶着補助部材と、を有することを特徴とする蓄電セル。 A positive electrode with a first current collector and
A negative electrode with a second current collector and
A seal member welded to the first current collector and the second current collector in the stacking direction in which the positive electrode and the negative electrode overlap each other.
A tubular member that extends through the seal member and
Between the tubular member in the stacking direction and the welded current collector of either the first current collector or the second current collector, the tubular member is in close contact with the welded current collector. A storage cell characterized by having a welding auxiliary member welded to an electric body. 前記溶着補助部材は、前記筒部材と前記シール部材との間に介在するとともに前記シール部材に溶着していることを特徴とする請求項１に記載の蓄電セル。 The storage cell according to claim 1, wherein the welding assist member is interposed between the tubular member and the seal member and is welded to the seal member. 前記溶着補助部材の材料は、前記シール部材の材料と同じであることを特徴とする請求項２に記載の蓄電セル。 The storage cell according to claim 2, wherein the material of the welding assist member is the same as the material of the seal member. 前記筒部材は、前記第１集電体と前記第２集電体と前記シール部材とによって画定される空間の外部から当該空間の内部へ電解液を注入するために用いられ、
前記筒部材は、前記筒部材の前記空間の外部寄りの端部を閉塞する閉塞部と、
前記閉塞部から前記筒部材の軸方向に沿って延びる通路と、を有することを特徴とする請求項１～請求項３のいずれか一項に記載の蓄電セル。 The tubular member is used to inject an electrolytic solution from the outside of the space defined by the first current collector, the second current collector, and the seal member into the inside of the space.
The tubular member includes a closed portion that closes an external end portion of the space of the tubular member, and a closed portion.
The storage cell according to any one of claims 1 to 3, further comprising a passage extending from the closed portion along the axial direction of the tubular member. 前記溶着補助部材は、前記筒部材の軸方向に沿って延びており、前記溶着補助部材の前記積層方向及び前記軸方向と直交する第１方向における寸法は、前記軸方向に沿って前記第１集電体と前記第２集電体と前記シール部材とによって画定される空間の内部から前記空間の外部に近づくに従い変化していることを特徴とする請求項１～請求項４のいずれか一項に記載の蓄電セル。 The welding assisting member extends along the axial direction of the tubular member, and the dimensions of the welding assisting member in the stacking direction and the first direction orthogonal to the axial direction are the first along the axial direction. One of claims 1 to 4, wherein the change is made from the inside of the space defined by the current collector, the second current collector, and the seal member toward the outside of the space. The storage cell described in the section. 前記シール部材は、前記積層方向において前記筒部材と重なる位置に、前記積層方向に沿って前記被溶着集電体から離れるように凹む凹部を有することを特徴とする請求項１～請求項５のいずれか一項に記載の蓄電セル。 Claims 1 to 5, wherein the seal member has a recess that is recessed along the stacking direction so as to be separated from the welded current collector at a position overlapping the cylinder member in the stacking direction. The storage cell according to any one of the items. 前記積層方向への前記凹部の寸法は、前記積層方向への前記筒部材の寸法と前記積層方向への前記溶着補助部材の寸法との和以上であることを特徴とする請求項６に記載の蓄電セル。 The sixth aspect of claim 6, wherein the dimension of the recess in the stacking direction is equal to or greater than the sum of the dimension of the tubular member in the stacking direction and the dimension of the welding assisting member in the stacking direction. Energy storage cell. 積層された複数の蓄電セルを有し、
前記複数の前記蓄電セルは、請求項１～請求項７のいずれか一項に記載の前記蓄電セルを含む蓄電装置。 It has multiple storage cells stacked and
The plurality of the storage cells are the storage devices including the storage cells according to any one of claims 1 to 7.
JP2020130305A 2020-07-31 2020-07-31 Power storage cell and power storage device Pending JP2022026712A (en)

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