JP7261911B2

JP7261911B2 - storage cell

Info

Publication number: JP7261911B2
Application number: JP2022007790A
Authority: JP
Inventors: 敦櫻井
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2018-10-18
Filing date: 2022-01-21
Publication date: 2023-04-20
Anticipated expiration: 2038-10-18
Also published as: JP2022046820A

Description

本発明は、蓄電セルに関する。 The present invention relates to storage cells.

ハイブリッドカーや電気自動車等に搭載される蓄電モジュールは、複数の蓄電セルにより構成される。一般に、蓄電セルは、セル缶と呼ばれる金属製の容器の内部に正極及び負極を有する電池要素を電解液と共に収納し、上方の開口部を封口体によって封止することにより構成される。封口体には正負一対の電極端子が突設される。 A power storage module mounted on a hybrid car, an electric vehicle, or the like is composed of a plurality of power storage cells. In general, a storage cell is constructed by housing a battery element having a positive electrode and a negative electrode together with an electrolytic solution inside a metal container called a cell can, and sealing an upper opening with a sealing member. A pair of positive and negative electrode terminals protrude from the sealing member.

ところで、蓄電セル内の電池要素は充放電によって膨張する。電池要素が膨張すると、蓄電セルのセル缶は外側に膨らむように変形する。このため、従来、複数の蓄電セルを積層方向に圧縮してケース内に収納し、蓄電セルを加圧した状態で使用することにより、電池要素の膨張を抑制して電池性能の向上を図ることが知られている（例えば、特許文献１参照）。 By the way, the battery element in the storage cell expands due to charging and discharging. When the battery element expands, the cell can of the storage cell deforms so as to expand outward. For this reason, conventionally, a plurality of storage cells are compressed in the stacking direction and housed in a case, and the storage cells are used in a pressurized state to suppress the expansion of the battery elements and improve the battery performance. is known (see, for example, Patent Document 1).

特開２０１７－１１１８９３号公報JP 2017-111893 A

しかしながら、蓄電セルを加圧しても、電池要素の膨張を完全に抑制することは困難である。電池要素の膨張によりセル缶が変形すると、特にセル缶と封口体との接合部に応力負荷が集中し、場合によっては接合部の破損につながるおそれがある。 However, even if the storage cell is pressurized, it is difficult to completely suppress the expansion of the battery element. When the cell can is deformed due to the expansion of the battery element, the stress load concentrates particularly on the junction between the cell can and the sealing member, which may lead to breakage of the junction in some cases.

そこで、本発明は、電池要素の膨張によるセル缶と封口体との接合部への応力負荷を低
減可能な蓄電セルを提供することを目的とする。 Accordingly, it is an object of the present invention to provide a storage cell capable of reducing the stress load on the junction between the cell can and the sealing body due to expansion of the battery element.

（１）本発明に係る蓄電セルは、セル缶（例えば、後述のセル缶１０）の内部に電池要素（例えば、後述の第１電池要素２Ａ、第２電池要素２Ｂ）が収納され、前記セル缶の上方の開口部（例えば、後述の開口部１０ａ）が封口体（例えば、後述の封口体１１）によって封止された蓄電セル（例えば、蓄電セル１）であって、前記セル缶の内部に、前記電池要素の膨張を受けて圧縮することにより前記電池要素の膨張力を吸収可能なシート状の膨張力吸収体（例えば、後述の膨張力吸収体４）を有し、前記電池要素は、前記膨張力吸収体と前記セル缶の内壁面（例えば、後述の内壁面１０ｂ）との間に配置され、前記膨張力吸収体は、前記電池要素の高さに対応する高さを有すると共に、前記セル缶の高さ方向の中央部よりも前記封口体側の剛性が低い、又は、前記セル缶の高さ方向の中央部よりも前記封口体側の厚さが小さい。 (1) In the storage cell according to the present invention, a battery element (for example, a first battery element 2A and a second battery element 2B described later) is housed inside a cell can (for example, a cell can 10 described later), and the cell A storage cell (for example, a storage cell 1) in which an upper opening (for example, an opening 10a described later) of the can is sealed with a sealing member (for example, a sealing member 11 described later), and the inside of the cell can a sheet-like expansion force absorber (for example, an expansion force absorber 4 described later) capable of absorbing the expansion force of the battery element by compressing the expansion of the battery element; , the expansion force absorber is disposed between the expansion force absorber and an inner wall surface of the cell can (for example, an inner wall surface 10b described later), and the expansion force absorber has a height corresponding to the height of the battery element; , the rigidity of the sealing member side is lower than that of the central portion in the height direction of the cell can, or the thickness of the sealing member side is smaller than that of the central portion of the cell can in the height direction.

上記（１）に記載の蓄電セルによれば、セル缶の内部において電池要素の膨張を膨張力吸収体によって吸収できるため、電池要素がセル缶を外側に膨らませようとする力が低減する。これにより、電池要素が膨張した際のセル缶と封口体との接合部への応力負荷を低減できる。しかも、電池要素は、セル缶の高さ方向の中央部よりも封口体側で膨張力吸収体側に膨張し易くなるため、セル缶と封口体との接合部への応力負荷をより良好に低減できる。 According to the storage cell described in (1) above, the expansion of the battery element can be absorbed by the expansion force absorber inside the cell can, so the force of the battery element to expand the cell can to the outside is reduced. This can reduce the stress load on the junction between the cell can and the sealing member when the battery element expands. Moreover, since the battery element expands more easily toward the expansion force absorber on the side of the sealing member than on the central portion in the height direction of the cell can, the stress load on the junction between the cell can and the sealing member can be reduced more satisfactorily. .

（２）（１）に記載の蓄電セルにおいて、前記膨張力吸収体は、弾性体又は膨潤性を有する構造体からなるものであってもよい。 (2) In the electric storage cell described in (1), the expansion force absorber may be composed of an elastic body or a structure having swelling properties.

上記（２）に記載の蓄電セルによれば、膨張力吸収体は、電池要素に対して密接した状態で、電池要素の膨張を受けて容易に圧縮して電池要素の膨張力を良好に吸収することができる。 According to the storage cell described in (2) above, the expansion force absorber is easily compressed by the expansion of the battery element while being in close contact with the battery element, and absorbs the expansion force of the battery element satisfactorily. can do.

（３）（２）に記載の蓄電セルにおいて、前記弾性体は、発泡体であり、前記膨潤性を有する構造体は、膨潤性樹脂又は樹脂繊維集合体であってもよい。 (3) In the electric storage cell according to (2), the elastic body may be a foam, and the swelling structure may be a swelling resin or a resin fiber assembly.

上記（３）に記載の蓄電セルによれば、軽量化、低コスト化を図ることが可能である。 According to the storage cell described in (3) above, weight reduction and cost reduction can be achieved.

（４）本発明に係る蓄電セルは、セル缶（例えば、後述のセル缶１０）の内部に電池要素（例えば、後述の第１電池要素２Ａ、第２電池要素２Ｂ）と電解液とが収納され、前記セル缶の上方の開口部（例えば、後述の開口部１０ａ）が封口体（例えば、後述の封口体１１）によって封止された蓄電セル（例えば、後述の蓄電セル１）であって、前記セル缶の内部に、前記電池要素の膨張を受けて圧縮することにより前記電池要素の膨張力を吸収可能なシート状の膨張力吸収体（例えば、後述の膨張力吸収体４）を有し、前記電池要素は、前記膨張力吸収体と前記セル缶の内壁面（例えば、後述の内壁面１０ｂ）との間に配置され、前記膨張力吸収体は、不透液性フィルム（例えば、後述の不透液性フィルム５）内に封入されている。 (4) In the storage cell according to the present invention, a battery element (for example, a first battery element 2A and a second battery element 2B, which will be described later) and an electrolyte are housed inside a cell can (for example, a cell can 10, which will be described later). A storage cell (for example, a storage cell 1 described later) in which an opening above the cell can (for example, an opening 10a described later) is sealed with a sealing member (for example, a sealing member 11 described later) a sheet-like expansion force absorber (for example, an expansion force absorber 4 to be described later) capable of absorbing the expansion force of the battery element by compressing the expansion of the battery element inside the cell can; The battery element is arranged between the expansion force absorber and the inner wall surface of the cell can (for example, an inner wall surface 10b described later), and the expansion force absorber is a liquid-impermeable film (for example, It is enclosed in a liquid-impermeable film 5) which will be described later.

上記（４）に記載の蓄電セルによれば、セル缶の内部において電池要素の膨張を膨張力吸収体によって吸収できるため、電池要素がセル缶を外側に膨らませようとする力が低減する。これにより、電池要素が膨張した際のセル缶と封口体との接合部への応力負荷を低減できる。しかも、膨張力吸収体への電解液の接触や滲み込みがなくなり、膨張力吸収体の変質や特性変化が防止されることにより、電池要素の膨張力の吸収作用を長期に安定化させることができる。また、電解液を電池要素の部分に限定して含浸させることができるため、電解液の使用量を削減でき、低コスト化が可能となる。 According to the storage cell described in (4) above, the expansion of the battery element can be absorbed by the expansion force absorber inside the cell can, so the force of the battery element to expand the cell can to the outside is reduced. This can reduce the stress load on the junction between the cell can and the sealing member when the battery element expands. In addition, the electrolyte does not come into contact with or seep into the expansion force absorber, and deterioration and characteristic changes of the expansion force absorber are prevented, so that the expansion force absorbing function of the battery element can be stabilized for a long period of time. can. In addition, since the electrolytic solution can be impregnated only in the portion of the battery element, the amount of electrolytic solution used can be reduced, and the cost can be reduced.

（５）（４）に記載の蓄電セルにおいて、前記膨張力吸収体は、弾性体又は膨潤性を有する構造体からなるものであってもよい。 (5) In the electric storage cell described in (4), the expansion force absorber may be made of an elastic body or a structure having swelling properties.

上記（５）に記載の蓄電セルによれば、膨張力吸収体は、電池要素に対して密接した状態で、電池要素の膨張を受けて容易に圧縮して電池要素の膨張力を良好に吸収することができる。 According to the storage cell described in (5) above, the expansion force absorber is easily compressed by the expansion of the battery element while being in close contact with the battery element, and absorbs the expansion force of the battery element satisfactorily. can do.

（６）（５）に記載の蓄電セルにおいて、前記弾性体は、発泡体であり、前記膨潤性を有する構造体は、膨潤性樹脂又は樹脂繊維集合体であってもよい。 (6) In the electric storage cell according to (5), the elastic body may be a foam, and the swelling structure may be a swelling resin or a resin fiber assembly.

上記（６）に記載の蓄電セルによれば、軽量化、低コスト化を図ることが可能である。 According to the storage cell described in (6) above, weight reduction and cost reduction can be achieved.

（７）（５）又は（６）に記載の蓄電セルにおいて、前記膨潤性を有する構造体は、液体（例えば、後述の液体Ｗ）と共に前記不透液性フィルム内に封入されていてもよい。 (7) In the electric storage cell according to (5) or (6), the swelling structure may be enclosed in the liquid-impermeable film together with a liquid (for example, a liquid W described later). .

上記（７）に記載の蓄電セルによれば、樹脂フィルム内の液体によって膨張力吸収体を膨潤させることができるため、初期から電池要素の膨張力の吸収作用を良好に発揮させることができる。 According to the electric storage cell described in (7) above, the liquid in the resin film can swell the expansion force absorber, so that the expansion force absorption function of the battery element can be satisfactorily exhibited from the initial stage.

（８）（７）に記載の蓄電セルにおいて、前記液体は、前記電解液から添加剤を除去した液体、又は、前記電解液とは別の液体であってもよい。 (8) In the electric storage cell according to (7), the liquid may be a liquid obtained by removing additives from the electrolytic solution, or a liquid different from the electrolytic solution.

上記（８）に記載の蓄電セルによれば、電解液よりも安価な液体を使用することができ、低コスト化が可能である。 According to the electric storage cell described in (8) above, it is possible to use a liquid that is cheaper than the electrolytic solution, and it is possible to reduce the cost.

（９）（１）～（８）のいずれかに記載の蓄電セルにおいて、前記膨張力吸収体は、前記セル缶の内部で厚さ方向に膨張することにより、前記電池要素を前記セル缶の内壁面に押し付けて保持するものであってもよい。 (9) In the storage cell according to any one of (1) to (8), the expansion force absorber expands in the thickness direction inside the cell can, thereby moving the battery element inside the cell can. It may be held by being pressed against the inner wall surface.

上記（９）に記載の蓄電セルによれば、電池要素とセル缶の内壁面との接触熱抵抗が低減し、電池要素の温度上昇も抑制できる。また、電池要素が、酸化物負極材等を適用した膨張が小さい電池要素の場合であっても、電池要素をセル缶の内壁面に対して均一に押し付けて保持することができる。 According to the storage cell described in (9) above, the contact thermal resistance between the battery element and the inner wall surface of the cell can is reduced, and the temperature rise of the battery element can be suppressed. In addition, even when the battery element is a battery element made of an oxide negative electrode material or the like and having a small expansion, the battery element can be uniformly pressed against the inner wall surface of the cell can and held.

（１０）（１）～（９）のいずれかに記載の蓄電セルにおいて、前記セル缶の内部に、２つの前記電池要素が収納され、前記膨張力吸収体は、２つの前記電池要素の間に挟まれているものであってもよい。 (10) In the storage cell according to any one of (1) to (9), two battery elements are housed inside the cell can, and the expansion force absorber is positioned between the two battery elements. It may be sandwiched between.

上記（１０）に記載の蓄電セルによれば、セル缶の両側面を伝熱面として利用することができると共に、膨張力吸収体を２つの電池要素に共通に利用することができるため、セル構造の簡素化及び低コスト化が可能である。 According to the storage cell described in (10) above, both side surfaces of the cell can can be used as heat transfer surfaces, and the expansion force absorber can be commonly used for two battery elements. Simplification of structure and cost reduction are possible.

（１１）（１０）に記載の蓄電セルにおいて、２つの前記電池要素は、前記セル缶の内部で直列接続されているものであってもよい。 (11) In the storage cell according to (10), the two battery elements may be connected in series inside the cell can.

上記（１１）に記載の蓄電セルによれば、膨張力吸収体を２つの電池要素間の絶縁距離として利用することができるため、２つの電池要素間に別途の絶縁部材を設ける必要がなくなり、セル構造の簡素化及び低コスト化が可能である。 According to the storage cell described in (11) above, since the expansion force absorber can be used as an insulating distance between the two battery elements, there is no need to provide a separate insulating member between the two battery elements. It is possible to simplify the cell structure and reduce the cost.

（１２）本発明に係る蓄電セルは、セル缶（例えば、後述のセル缶１０）の内部に電池要素（例えば、第１電池要素２Ａ、第２電池要素２Ｂ）が収納され、前記セル缶の上方の開口部（例えば、後述の開口部１０ａ）が封口体（例えば、後述の封口体１１）によって封止された蓄電セル（例えば、後述の蓄電セル１）の製造方法であって、前記電池要素の膨張を受けて圧縮することにより前記電池要素の膨張力を吸収可能なシート状の膨張力吸収体（例えば、後述の膨張力吸収体４）を、前記電池要素と積層し、前記膨張力吸収体は、前記電池要素の高さに対応する高さを有すると共に、前記セル缶の高さ方向の中央部よりも前記封口体側の剛性が低い、又は、前記セル缶の高さ方向の中央部よりも前記封口体側の厚さが小さいものであり、前記膨張力吸収体を厚さ方向に押し潰した状態で、前記電池要素と共に前記セル缶の内部に挿入し、その後、前記膨張力吸収体の膨張によって、前記電池要素を前記セル缶の内壁面（例えば、後述の内壁面１０ｂ）に押し付けて保持する。 (12) In the storage cell according to the present invention, a battery element (for example, a first battery element 2A and a second battery element 2B) is housed inside a cell can (for example, a cell can 10 described later), and the cell can A method for manufacturing a storage cell (for example, a storage cell 1 described later) in which an upper opening (for example, an opening 10a described later) is sealed with a sealing member (for example, a sealing member 11 described later), A sheet-like expansion force absorber (for example, an expansion force absorber 4 described later) capable of absorbing the expansion force of the battery element by compressing the expansion force of the element is laminated with the battery element, and the expansion force is The absorber has a height corresponding to the height of the battery element, and has lower rigidity on the side of the sealing member than the central portion of the cell can in the height direction, or is located at the center of the cell can in the height direction. The expansion force absorber is inserted into the cell can together with the battery element in a state where the expansion force absorber is crushed in the thickness direction, and then the expansion force absorber is inserted into the cell can. The expansion of the body presses and holds the battery element against the inner wall surface of the cell can (for example, an inner wall surface 10b to be described later).

上記（１２）に記載の蓄電セルの製造方法によれば、セル缶の内部の電池要素を、押し潰された膨張力吸収体自体の膨張力によって、セル缶の内壁面に均一に押し付けて保持することができるため、電池要素とセル缶の内壁面との接触熱抵抗が低減し、電池要素の温度上昇も抑制できる。しかも、電池要素が、酸化物負極材等を適用した膨張が小さい電池要素の場合であっても、電池要素をセル缶の内壁面に対して均一に押し付けて保持することができる。更に、電池要素をセル缶の内部に挿入する際に、膨張力吸収体が押し潰されて変形することにより、容易に挿入できるようになり、蓄電セルの組立て性が向上する。 According to the storage cell manufacturing method described in (12) above, the battery element inside the cell can is uniformly pressed against the inner wall surface of the cell can and held by the expansion force of the crushed expansion force absorber itself. Therefore, the contact thermal resistance between the battery element and the inner wall surface of the cell can is reduced, and the temperature rise of the battery element can be suppressed. Moreover, even if the battery element is made of an oxide negative electrode material or the like and has a small expansion, the battery element can be uniformly pressed and held against the inner wall surface of the cell can. Furthermore, when the battery element is inserted into the cell can, the expansive force absorber is crushed and deformed, thereby facilitating insertion and improving the assembling efficiency of the storage cell.

本発明によれば、本発明は、電池要素の膨張によるセル缶と封口体との接合部への応力負荷を低減可能な蓄電セル及び蓄電セルの製造方法を提供することができる。 According to the present invention, it is possible to provide a storage cell and a storage cell manufacturing method capable of reducing the stress load on the junction between the cell can and the sealing member due to expansion of the battery element.

本発明の一実施形態に係る蓄電セルを示す斜視図である。1 is a perspective view showing a storage cell according to one embodiment of the present invention; FIG. 図１に示す蓄電セルの分解斜視図である。FIG. 2 is an exploded perspective view of the storage cell shown in FIG. 1; 図１中のＸ－Ｘ線に沿う断面図である。FIG. 2 is a cross-sectional view taken along line XX in FIG. 1; 図３に示す蓄電セルの上部を拡大して示す断面図である。FIG. 4 is a cross-sectional view showing an enlarged upper portion of the storage cell shown in FIG. 3 ; 図１に示す蓄電セルの内部を透視して示す斜視図である。FIG. 2 is a perspective view showing through the inside of the storage cell shown in FIG. 1 ; 封口体に接続された電池要素を斜め下から見た図である。FIG. 4 is a diagram of the battery element connected to the sealing body as viewed obliquely from below; 本発明に係る蓄電セルの製造方法を説明する断面図である。It is sectional drawing explaining the manufacturing method of the electrical storage cell which concerns on this invention. 本発明の他の実施形態に係る蓄電セルの断面図である。FIG. 5 is a cross-sectional view of a storage cell according to another embodiment of the present invention; 樹脂フィルム内に封入された膨張力吸収体の一例を示す断面図である。FIG. 4 is a cross-sectional view showing an example of an expansive force absorber enclosed in a resin film; 本発明の更に他の実施形態に係る蓄電セルの断面図である。FIG. 5 is a cross-sectional view of a storage cell according to still another embodiment of the present invention; 本発明の更に他の実施形態に係る蓄電セルの断面図である。FIG. 5 is a cross-sectional view of a storage cell according to still another embodiment of the present invention;

以下、本発明の実施の形態について図面を参照して詳細に説明する。
蓄電セル１は、セル缶１０の内部に、２つの電池要素（第１電池要素２Ａ、第２電池要素２Ｂ）を電解液（図示せず）と共に収納し、封口体１１で封止することにより構成される。なお、各図中に示す方向において、Ｄ１方向は蓄電セル１の長さ方向を示し、Ｄ２方向は蓄電セル１の厚さ方向を示し、Ｄ３方向は蓄電セル１の高さ方向を示す。このＤ３方向の矢印が示す方向は重力方向に沿う上方である。 BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
In the storage cell 1, two battery elements (a first battery element 2A and a second battery element 2B) are housed inside a cell can 10 together with an electrolytic solution (not shown) and sealed with a sealing member 11. Configured. In the directions shown in each figure, the D1 direction indicates the length direction of the storage cell 1, the D2 direction indicates the thickness direction of the storage cell 1, and the D3 direction indicates the height direction of the storage cell 1. The direction indicated by the D3 direction arrow is upward along the direction of gravity.

セル缶１０は、アルミニウムやアルミニウム合金等の金属材により、Ｄ１方向に長い略直方体状に成形された有底箱型の容器である。セル缶１０の上方は開放され、矩形状の開口部１０ａを有する。 The cell can 10 is a bottomed box-shaped container made of a metal material such as aluminum or an aluminum alloy and formed into a substantially rectangular parallelepiped shape elongated in the D1 direction. The top of the cell can 10 is open and has a rectangular opening 10a.

封口体１１は、アルミニウムやアルミニウム合金等の金属材により、セル缶１０の開口部１０ａと同一の矩形状に形成された平板部材からなる。封口体１１は、セル缶１０の開口部１０ａの内周面に嵌合され、溶接やかしめ等によって開口部１０ａの内周面に対して接合される。これにより、セル缶１０の開口部１０ａと封口体１１との間には、開口部１０ａに沿う接合部１００が形成される。 The sealing member 11 is made of a metal material such as aluminum or an aluminum alloy and is a flat plate member formed in the same rectangular shape as the opening 10 a of the cell can 10 . The sealing member 11 is fitted to the inner peripheral surface of the opening 10a of the cell can 10 and joined to the inner peripheral surface of the opening 10a by welding, caulking or the like. As a result, a joint 100 is formed between the opening 10a of the cell can 10 and the sealing member 11 along the opening 10a.

封口体１１は、長さ方向（Ｄ１方向）の両端に離れて配置される正極端子１２と負極端子１３とを有する。正極端子１２及び負極端子１３は、それぞれ封口体１１を貫通して上面に突出している。正極端子１２及び負極端子１３と封口体１１との間は、絶縁材（図示せず）によって電気的に絶縁されている。また、封口体１１は、正極端子１２と負極端子１３との間に、圧力解放弁（安全弁）１４と、電解液の注液口１５とを有する。 The sealing member 11 has a positive electrode terminal 12 and a negative electrode terminal 13 that are spaced apart from each other at both ends in the length direction (D1 direction). The positive electrode terminal 12 and the negative electrode terminal 13 each penetrate the sealing member 11 and protrude upward. An insulating material (not shown) electrically insulates between the positive terminal 12 and the negative terminal 13 and the sealing member 11 . In addition, the sealing member 11 has a pressure release valve (safety valve) 14 and an electrolyte injection port 15 between the positive electrode terminal 12 and the negative electrode terminal 13 .

セル缶１０の内部の第１電池要素２Ａ及び第２電池要素２Ｂは、図４に示すように、複数の正極板２０１と複数の負極板２０２とを、セパレータ２０３を介して交互に積層した積層構造を有する。正極板２０１は、正極箔２０１ａと、その正極箔２０１ａの両面に塗布された正極活物質２０１ｂとで構成される。負極板２０２は、負極箔２０２ａと、その負極箔２０２ａの両面に塗布された負極活物質２０２ｂとで構成される。 The first battery element 2A and the second battery element 2B inside the cell can 10 are, as shown in FIG. have a structure. The positive electrode plate 201 is composed of a positive electrode foil 201a and a positive electrode active material 201b applied on both sides of the positive electrode foil 201a. The negative electrode plate 202 is composed of a negative electrode foil 202a and a negative electrode active material 202b applied to both surfaces of the negative electrode foil 202a.

第１電池要素２Ａは、上部に正極集電部２１Ａと負極集電部２２Ａとを有する。正極集電部２１Ａは、各正極板２０１の正極箔２０１ａの上端が部分的に帯状に延出され、積層されて１つに束ねられている。また、負極集電部２２Ａは、各負極板２０２の負極箔２０２ａの上端が部分的に帯状に延出され、積層されて１つに束ねられている。正極集電部２１Ａ及び負極集電部２２Ａは、それぞれ第１電池要素２Ａの上部において横向きに屈曲され、封口体１１に対して略平行な矩形状の平面を形成している。 The first battery element 2A has a positive electrode current collector 21A and a negative electrode current collector 22A in the upper part. The positive electrode current collecting portion 21A is formed by partially extending the upper end of the positive electrode foil 201a of each positive electrode plate 201 in a belt shape and stacking and bundling them into one. Further, the negative electrode current collecting portion 22A is formed by partially extending the upper ends of the negative electrode foils 202a of the negative electrode plates 202 in a belt shape, and stacking and bundling them into one. The positive electrode current collector 21A and the negative electrode current collector 22A are each bent laterally at the upper portion of the first battery element 2A to form a rectangular plane substantially parallel to the sealing member 11 .

第１電池要素２Ａの正極集電部２１Ａは、第１電池要素２Ａの上部における長さ方向（Ｄ１方向）の一方端部に配置され、各正極板２０１の正極箔２０１ａの一方端部の上端が部分的に帯状に延出されることにより形成される。また、負極集電部２２Ａは、第１電池要素２Ａの上部における長さ方向（Ｄ１方向）の他方端部よりもやや中央寄りにずれて配置され、各負極板２０２の負極箔２０２ａの他方端部よりもやや中央寄りの上端が部分的に帯状に延出されることにより形成される。 The positive current collecting portion 21A of the first battery element 2A is arranged at one end in the length direction (D1 direction) of the upper portion of the first battery element 2A, and the upper end of the one end of the positive electrode foil 201a of each positive electrode plate 201 is partially extended in a strip shape. In addition, the negative electrode current collecting portion 22A is arranged slightly shifted toward the center from the other end portion in the length direction (D1 direction) of the upper portion of the first battery element 2A. The upper end slightly closer to the center than the part is formed by partially extending in a belt shape.

一方、第２電池要素２Ｂも、上部に正極集電部２１Ｂと負極集電部２２Ｂとを有する。正極集電部２１Ｂは、各正極板２０１の正極箔２０１ａの上端が部分的に帯状に延出され、積層されて１つに束ねられている。また、負極集電部２２Ｂは、各負極板２０２の負極箔２０２ａの上端が部分的に帯状に延出され、積層されて１つに束ねられている。正極集電部２１Ｂ及び負極集電部２２Ｂは、それぞれ第２電池要素２Ｂの上部において横向きに屈曲され、封口体１１に対して略平行な矩形状の平面を形成している。 On the other hand, the second battery element 2B also has a positive electrode current collector 21B and a negative electrode current collector 22B on its upper portion. The positive electrode current collecting portion 21B is formed by partially extending the upper end of the positive electrode foil 201a of each positive electrode plate 201 in a belt shape, and stacking and bundling them into one. Further, the negative electrode current collecting portion 22B is formed by partially extending the upper ends of the negative electrode foils 202a of the negative electrode plates 202 in a belt shape, and stacking and bundling them into one. The positive electrode current collector 21B and the negative electrode current collector 22B are each bent laterally at the upper portion of the second battery element 2B to form a rectangular plane substantially parallel to the sealing member 11 .

第２電池要素２Ｂの正極集電部２１Ｂは、第２電池要素２Ｂの上部における長さ方向（Ｄ１方向）の一方端部よりもやや中央寄りにずれて配置され、各正極板２０１の正極箔２０１ａの一方端部よりもやや中央寄りの上端が部分的に帯状に延出されることにより形成される。また、負極集電部２２Ｂは、第２電池要素２Ｂの上部における長さ方向（Ｄ１方向）の他方端部に配置され、各負極板２０２の負極箔２０２ａの他方端部の上端が部分的に帯状に延出されることにより形成される。 The positive electrode current collecting portion 21B of the second battery element 2B is arranged slightly closer to the center than one end in the length direction (D1 direction) of the upper portion of the second battery element 2B. The upper end slightly closer to the center than the one end of 201a is partially extended in a strip shape. In addition, the negative electrode current collector 22B is arranged at the other end in the length direction (D1 direction) of the upper portion of the second battery element 2B, and the upper end of the other end of the negative electrode foil 202a of each negative electrode plate 202 is partially It is formed by extending in a strip shape.

第１電池要素２Ａ及び第２電池要素２Ｂは、図２、図３に示すように、それぞれ絶縁部材３Ａ、３Ｂに個別に収容される。絶縁部材３Ａ、３Ｂは、いずれも絶縁性のシート材により、第１電池要素２Ａ及び第２電池要素２Ｂとほぼ同形状で、上部が開口する袋状に形成される。第１電池要素２Ａ及び第２電池要素２Ｂは、正極集電部２１Ａ、２１Ｂと負極集電部２２Ａ、２２Ｂとが上方に配向されて、絶縁部材３Ａ、３Ｂ内にそれぞれ収容される。なお、以下の説明における第１電池要素２Ａ及び第２電池要素２Ｂは、絶縁部材３Ａ
、３Ｂに収容された状態のものを指すものとする。 The first battery element 2A and the second battery element 2B are individually housed in insulating members 3A and 3B, respectively, as shown in FIGS. Each of the insulating members 3A and 3B is made of an insulating sheet material and has substantially the same shape as the first battery element 2A and the second battery element 2B. The first battery element 2A and the second battery element 2B are accommodated in the insulating members 3A and 3B, respectively, with the positive current collectors 21A and 21B and the negative current collectors 22A and 22B oriented upward. Note that the first battery element 2A and the second battery element 2B in the following description refer to the insulating member 3A.
, 3B.

第１電池要素２Ａ及び第２電池要素２Ｂは、正極板２０１と負極板２０２の積層方向に沿う蓄電セル１の厚さ方向（Ｄ２方向）に並列される。第１電池要素２Ａの正極集電部２１Ａは、図５、図６に示すように、封口体１１の裏面において正極端子１２と電気的に接続される。また、第１電池要素２Ａの負極集電部２２Ａは、負極端子１３寄りの封口体１１の裏面に電気的に接続される。一方、第２電池要素２Ｂの正極集電部２１Ｂは、正極端子１２寄りの封口体１１の裏面に電気的に接続される。また、第２電池要素２Ｂの負極集電部２２Ｂは、封口体１１の裏面において負極端子１３と電気的に接続される。これにより、セル缶１０内の第１電池要素２Ａと第２電池要素２Ｂとは、封口体１１を介して直列接続される。 The first battery element 2A and the second battery element 2B are arranged in parallel in the thickness direction (D2 direction) of the storage cell 1 along the stacking direction of the positive electrode plate 201 and the negative electrode plate 202 . The positive current collecting portion 21A of the first battery element 2A is electrically connected to the positive terminal 12 on the rear surface of the sealing member 11, as shown in FIGS. Further, the negative electrode current collecting portion 22A of the first battery element 2A is electrically connected to the back surface of the sealing member 11 near the negative electrode terminal 13 . On the other hand, the positive electrode collector portion 21B of the second battery element 2B is electrically connected to the rear surface of the sealing member 11 near the positive electrode terminal 12 . Also, the negative electrode current collector 22B of the second battery element 2B is electrically connected to the negative electrode terminal 13 on the back surface of the sealing member 11 . As a result, the first battery element 2A and the second battery element 2B in the cell can 10 are connected in series via the sealing member 11 .

セル缶１０の内部には、電解液（図示せず）と共に、封口体１１を取り付けた第１電池要素２Ａ及び第２電池要素２Ｂと膨張力吸収体４とが収納される。膨張力吸収体４は、セル缶１０内の第１電池要素２Ａ及び第２電池要素２Ｂが膨張した際にその膨張を受けて圧縮することにより、第１電池要素２Ａ及び第２電池要素２Ｂの膨張力を吸収可能なシート状の構造体により構成される。 The cell can 10 accommodates the first battery element 2A and the second battery element 2B with the sealing member 11 attached thereto, and the expansion force absorber 4 together with an electrolytic solution (not shown). When the first battery element 2A and the second battery element 2B in the cell can 10 expand, the expansion force absorber 4 receives the expansion and compresses the first battery element 2A and the second battery element 2B. It is composed of a sheet-like structure capable of absorbing expansion force.

膨張力吸収体４は、図２に示すように、第１電池要素２Ａ及び第２電池要素２Ｂの側面形状（Ｄ２方向に面する側面の形状）と略同一の矩形のシート状に形成されると共に、図３に示すように、第１電池要素２Ａ及び第２電池要素２Ｂの高さに対応する高さを有する。なお、本実施形態に示す膨張力吸収体４は、絶縁性材料の適用もしくは絶縁性フィルム内に収納することにより、絶縁体としても利用することが可能である。 As shown in FIG. 2, the expansion force absorber 4 is formed in a rectangular sheet shape that is substantially the same as the side surface shape (the shape of the side surface facing the direction D2) of the first battery element 2A and the second battery element 2B. In addition, as shown in FIG. 3, it has a height corresponding to the height of the first battery element 2A and the second battery element 2B. The expansive force absorber 4 shown in this embodiment can also be used as an insulator by applying an insulating material or encasing it in an insulating film.

膨張力吸収体４は、図３に示すように、第１電池要素２Ａと第２電池要素２Ｂとの間に挟まれて密接している。第１電池要素２Ａ及び第２電池要素２Ｂは、膨張力吸収体４と接する側と反対側において、セル缶１０の内壁面１０ｂ、１０ｂにそれぞれ密接している。 As shown in FIG. 3, the expansion force absorber 4 is sandwiched between the first battery element 2A and the second battery element 2B and is in close contact therewith. The first battery element 2A and the second battery element 2B are in close contact with the inner wall surfaces 10b, 10b of the cell can 10 on the side opposite to the side in contact with the expansion force absorber 4, respectively.

図２、図３に示す膨張力吸収体４は、高さ方向（Ｄ３方向）に２分割されている。即ち、膨張力吸収体４は、高さ方向の上方（封口体１１側）に配置される第１吸収体４１と、高さ方向の下方（セル缶１０の底部１０ｃ側）に配置される第２吸収体４２とで構成される。第１吸収体４１と第２吸収体４２とは、高さ方向に積み重ねられている。第１吸収体４１は、第２吸収体４２に比べて高さが低い。従って、第１吸収体４１と第２吸収体４２との境界部４ａは、セル缶１０の高さ方向の中央部よりも封口体１１寄りに配置されている。 The expansive force absorber 4 shown in FIGS. 2 and 3 is divided into two in the height direction (D3 direction). That is, the expansive force absorbers 4 are composed of a first absorber 41 arranged above in the height direction (closer to the sealing member 11) and a first absorber 41 arranged below in the height direction (closer to the bottom 10c of the cell can 10). 2 absorber 42 . The first absorbent body 41 and the second absorbent body 42 are stacked in the height direction. The first absorbent body 41 has a lower height than the second absorbent body 42 . Therefore, the boundary part 4a between the first absorbent body 41 and the second absorbent body 42 is arranged closer to the sealing body 11 than the central part of the cell can 10 in the height direction.

第１吸収体４１と第２吸収体４２とは、ほぼ同一厚さを有するが、剛性が異なっている。即ち、第１吸収体４１の剛性の方が、第２吸収体４２の剛性よりも低い。このため、第１電池要素２Ａ及び第２電池要素２Ｂの膨張力を受けた際に、第１吸収体４１は、第２吸収体４２に比較して大きく圧縮可能であり、それだけより多くの膨張力を吸収することができる。 The first absorbent body 41 and the second absorbent body 42 have substantially the same thickness, but differ in rigidity. That is, the rigidity of the first absorbent body 41 is lower than that of the second absorbent body 42 . Therefore, when receiving the expansion forces of the first battery element 2A and the second battery element 2B, the first absorbent body 41 can be compressed more greatly than the second absorbent body 42, and accordingly expands more. It can absorb power.

ここで、第１電池要素２Ａ及び第２電池要素２Ｂが膨張した場合、その膨張力は、セル缶１０の内壁面１０ｂ、１０ｂの全面に略均等に作用する。しかし、セル缶１０は有底であり、セル缶１０の上方は封口体１１によって封止されているため、セル缶１０を高さ方向に見た場合、セル缶１０の高さ方向の中央部が外側に向けて最も大きく膨らむようになる。このとき、セル缶１０の下方は、セル缶１０の底部１０ｃと側部１０ｄとが一体に成形されているため、第１電池要素２Ａ及び第２電池要素２Ｂの膨張力に十分に耐え得る。しかし、セル缶１０の上方は、セル缶１０が膨らんだ際に、セル缶１０の開口部１０ａと封口体１１との接合部１００に応力負荷が集中し、接合部１００の破損につながるおそれがある。 Here, when the first battery element 2A and the second battery element 2B expand, the expansion force acts on the entire surfaces of the inner wall surfaces 10b, 10b of the cell can 10 substantially evenly. However, since the cell can 10 has a bottom and the top of the cell can 10 is sealed by the sealing member 11, when the cell can 10 is viewed in the height direction, the central portion of the cell can 10 in the height direction bulges outward the most. At this time, since the bottom portion 10c and the side portion 10d of the cell can 10 are formed integrally, the lower portion of the cell can 10 can sufficiently withstand the expansion force of the first battery element 2A and the second battery element 2B. However, above the cell can 10, when the cell can 10 swells, the stress load concentrates on the joint 100 between the opening 10a of the cell can 10 and the sealing member 11, which may lead to breakage of the joint 100. be.

これに対し、膨張力吸収体４は、セル缶１０の内部で第１電池要素２Ａ及び第２電池要素２Ｂの膨張を受けて圧縮することにより、その膨張力を吸収する。このとき、封口体１１に近い側に配置される第１吸収体４１は、第２吸収体４２に比較して剛性が低いため、第１電池要素２Ａ及び第２電池要素２Ｂは、セル缶１０の高さ方向の中央部よりも封口体１１側で、内壁面１０ｂ側よりも膨張力吸収体４側に膨張し易くなり、第２吸収体４２よりも大きく圧縮され、より多くの膨張力を吸収する。その結果、図３に示すように、第１吸収体４１に対応するセル缶１０の上方側の内壁面１０ｂ、１０ｂに作用する電池要素の膨張力Ｆ１は、第２吸収体４２に対応するセル缶１０の中央部の内壁面１０ｂ、１０ｂに作用する電池要素の膨張力Ｆ２よりも小さくなる。これにより、接合部１００への応力負荷が低減され、蓄電セル１は耐久性に優れるようになる。 On the other hand, the expansion force absorber 4 absorbs the expansion force by receiving the expansion of the first battery element 2A and the second battery element 2B inside the cell can 10 and compressing it. At this time, since the first absorber 41 arranged on the side closer to the sealing member 11 has lower rigidity than the second absorber 42, the first battery element 2A and the second battery element 2B are arranged in the cell can 10. It becomes easier to expand toward the expansion force absorber 4 side than toward the inner wall surface 10b side, and is compressed more than the second absorber 42, and exerts more expansion force than the second absorber 42. Absorb. As a result, as shown in FIG. 3, the expansion force F1 of the battery element acting on the inner wall surfaces 10b, 10b on the upper side of the cell can 10 corresponding to the first absorber 41 increases the cell corresponding to the second absorber 42. It is smaller than the expansion force F2 of the battery element acting on the inner wall surfaces 10b, 10b in the central portion of the can 10. As a result, the stress load on the joint 100 is reduced, and the storage cell 1 becomes excellent in durability.

膨張力吸収体４としては、シート状に成形可能であり、第１電池要素２Ａ及び第２電池要素２Ｂの膨張力を受けた際に圧縮して膨張力を吸収可能なものであれば特に制限なく使用できるが、弾性体又は膨潤性を有する構造体を好ましく使用することができる。 The expansion force absorber 4 is particularly limited as long as it can be formed into a sheet shape and can be compressed to absorb the expansion force when receiving the expansion force of the first battery element 2A and the second battery element 2B. However, an elastic body or a swellable structure can be preferably used.

弾性体としては、一般的なゴムや樹脂からなる弾性体を使用することができる。中でも、弾性体がゴムや樹脂の発泡体である場合は、蓄電セル１の軽量化及び低コスト化を図ることができる。また、発泡体は、発泡倍率を適宜設定することにより、第１吸収体４１と第２吸収体４２との剛性の高低差を容易に設けることができる。 As the elastic body, an elastic body made of general rubber or resin can be used. Among others, when the elastic body is a rubber or resin foam, the weight and cost of the storage cell 1 can be reduced. Moreover, by appropriately setting the expansion ratio of the foam, it is possible to easily provide a difference in rigidity between the first absorbent body 41 and the second absorbent body 42 .

膨潤性を有する構造体としては、液体（電解液を含む。）を含浸することにより膨潤する膨潤性樹脂や樹脂繊維集合体を使用することができる。これにより、発泡体を使用する場合と同様に、蓄電セル１の軽量化及び低コスト化を図ることができる。具体的な膨潤性樹脂としては、ＰＶＤＦ（ポリフッ化ビニリデン）やシリコーン樹脂が例示される。また、具体的な樹脂繊維集合体としては、ポリオレフィン系樹脂繊維やフェノール樹脂繊維の不織布の積層体が例示される。第１吸収体４１と第２吸収体４２との剛性の高低差は、樹脂や樹脂繊維の密度、種類、径、長さ、形状を適宜調整することにより設けることができる。 As the structure having swelling properties, a swelling resin or a resin fiber aggregate that swells when impregnated with a liquid (including an electrolytic solution) can be used. This makes it possible to reduce the weight and cost of the storage cell 1, as in the case of using foam. Examples of specific swelling resins include PVDF (polyvinylidene fluoride) and silicone resins. Further, as a specific resin fiber assembly, a laminate of nonwoven fabrics of polyolefin resin fibers and phenol resin fibers is exemplified. The difference in rigidity between the first absorbent body 41 and the second absorbent body 42 can be provided by appropriately adjusting the density, type, diameter, length and shape of the resin and resin fibers.

本実施形態に示す第１電池要素２Ａ及び第２電池要素２Ｂは、セル缶１０の内部において、膨張力吸収体４と接する側と反対側の内壁面１０ｂ、１０ｂにそれぞれ密接している。これにより、第１電池要素２Ａ及び第２電池要素２Ｂの熱は、セル缶１０の内壁面１０ｂ、１０ｂからセル缶１０に伝達される。このため、セル缶１０の外側面を伝熱面として利用することができる。また、膨張力吸収体４は第１電池要素２Ａと第２電池要素２Ｂとに共通であるため、セル缶１０内の電池要素の数に対する膨張力吸収体４の数を削減でき、セル構造の簡素化及び低コスト化を図ることができる。 The first battery element 2A and the second battery element 2B shown in this embodiment are in close contact with the inner wall surfaces 10b, 10b on the opposite side of the expansion force absorber 4 inside the cell can 10, respectively. Thereby, the heat of the first battery element 2A and the second battery element 2B is transferred to the cell can 10 from the inner wall surfaces 10b, 10b of the cell can 10. As shown in FIG. Therefore, the outer surface of the cell can 10 can be used as a heat transfer surface. Further, since the expansion force absorber 4 is common to the first battery element 2A and the second battery element 2B, the number of expansion force absorbers 4 can be reduced with respect to the number of battery elements in the cell can 10, and the cell structure can be reduced. Simplification and cost reduction can be achieved.

また、膨張力吸収体４が第１電池要素２Ａと第２電池要素２Ｂとの間に配置されることにより、第１電池要素２Ａと第２電池要素２Ｂとの間に、膨張力吸収体４の厚さに相当する絶縁距離を設けることができる。このため、直列接続される第１電池要素２Ａと第２電池要素２Ｂとの間に、絶縁距離を確保するための別途の絶縁部材を設ける必要がない。従って、更にセル構造の簡素化及び低コスト化を図ることができる。 Further, by arranging the expansion force absorber 4 between the first battery element 2A and the second battery element 2B, the expansion force absorber 4 is placed between the first battery element 2A and the second battery element 2B. An insulation distance corresponding to the thickness of the Therefore, it is not necessary to provide a separate insulating member for securing an insulating distance between the first battery element 2A and the second battery element 2B that are connected in series. Therefore, it is possible to further simplify the cell structure and reduce the cost.

膨張力吸収体４は、セル缶１０の内部において厚さ方向（Ｄ２方向）に沿って膨張することにより、第１電池要素２Ａ及び第２電池要素２Ｂに対して、セル缶１０内壁面１０ｂ、１０ｂに向けて押し付けて、第１電池要素２Ａ及び第２電池要素２Ｂを膨張力吸収体４とセル缶１０の内壁面１０ｂ、１０ｂとの間に保持するようにしてもよい。これにより、第１電池要素２Ａ及び第２電池要素２Ｂとセル缶１０の内壁面１０ｂ、１０ｂとの接触熱抵抗が低減し、第１電池要素２Ａ及び第２電池要素２Ｂの温度上昇を抑制することができる。また、第１電池要素２Ａ及び第２電池要素２Ｂが、ＬＴＯ（チタン酸リチウム）等の酸化物負極材等を適用した膨張が小さい電池要素の場合であっても、第１電池要素２Ａ及び第２電池要素２Ｂをセル缶の内壁面１０ｂ、１０ｂに対して均一に押し付けて保持することができる。 The expansion force absorber 4 expands along the thickness direction (D2 direction) inside the cell can 10, and thereby the inner wall surface 10b of the cell can 10 and the inner wall surface 10b, 10b to hold the first battery element 2A and the second battery element 2B between the expansion force absorber 4 and the inner wall surfaces 10b, 10b of the cell can 10. FIG. As a result, the contact thermal resistance between the first battery element 2A and the second battery element 2B and the inner wall surfaces 10b and 10b of the cell can 10 is reduced, and the temperature rise of the first battery element 2A and the second battery element 2B is suppressed. be able to. Further, even in the case where the first battery element 2A and the second battery element 2B are battery elements that use an oxide negative electrode material such as LTO (lithium titanate) and have a small expansion, the first battery element 2A and the second battery element 2B The two-battery element 2B can be held by being uniformly pressed against the inner wall surfaces 10b, 10b of the cell can.

本実施形態の第１電池要素２Ａ及び第２電池要素２Ｂのように、正極板２０１と負極板２０２とをセパレータ２０３を挟んで積層した積層構造を有する電池要素は、巻回構造からなる電池要素とは異なり、巻回部による変形効果がないため、セル缶１０の内部において内壁面１０ｂ、１０ｂへの押し付け荷重を確保することが困難である。しかし、膨張力吸収体４がセル缶１０内で膨張することにより、積層構造を有する第１電池要素２Ａ及び第２電池要素２Ｂを使用する場合でも、セル缶１０の内壁面１０ｂ、１０ｂへの押し付け荷重を容易に確保することができる。 Like the first battery element 2A and the second battery element 2B of the present embodiment, a battery element having a laminated structure in which a positive electrode plate 201 and a negative electrode plate 202 are laminated with a separator 203 interposed therebetween has a wound structure. Unlike , there is no deformation effect due to the winding portion, so it is difficult to ensure a pressing load against the inner wall surfaces 10b, 10b inside the cell can 10 . However, as the expansion force absorber 4 expands inside the cell can 10, even when the first battery element 2A and the second battery element 2B having a laminated structure are used, the inner wall surfaces 10b, 10b of the cell can 10 will not be affected. A pressing load can be easily ensured.

膨張力吸収体４の膨張は、例えば、膨張力吸収体４が弾性体である場合の弾性復元力や、膨張力吸収体４が膨潤性を有する構造体である場合の膨潤による膨張を利用することができる。但し、この場合の膨張力吸収体４が第１電池要素２Ａ及び第２電池要素２Ｂに対して作用させる膨張力は、第１電池要素２Ａ及び第２電池要素２Ｂが膨張力吸収体４に対して作用させる膨張力よりも小さいものである。このため、膨張力吸収体４自体の膨張力が、第１電池要素２Ａ及び第２電池要素２Ｂの膨張力を吸収する際の障害となることはない。 The expansion of the expansive force absorber 4 uses, for example, elastic restoring force when the expansive force absorber 4 is an elastic body, or expansion due to swelling when the expansive force absorber 4 is a structure having swelling properties. be able to. However, the expansion force that the expansion force absorber 4 exerts on the first battery element 2A and the second battery element 2B in this case is It is smaller than the expansive force exerted by the Therefore, the expansive force of the expansive force absorber 4 itself does not interfere with absorbing the expansive force of the first battery element 2A and the second battery element 2B.

このように膨張力吸収体４が第１電池要素２Ａ及び第２電池要素２Ｂを押し付けて保持する機能を発揮するためには、膨張力吸収体４を押し潰した状態でセル缶１０の内部に収納する方法が採用できる。即ち、図７に示すように、先ず、予め封口体１１が取り付けられた第１電池要素２Ａと第２電池要素２Ｂとの間に、膨張力吸収体４を挟むように積層させる。次いで、第１電池要素２Ａと第２電池要素２Ｂとを厚さ方向（Ｄ２方向）の両側から圧縮することにより、膨張力吸収体４を厚さ方向に押し潰した状態で、第１電池要素２Ａ及び第２電池要素２Ｂと共に膨張力吸収体４をセル缶１０の内部に挿入する。その後、セル缶１０の内部において、膨張力吸収体４が弾性復元力や膨潤によって膨張すると、膨張力吸収体４は、第１電池要素２Ａ及び第２電池要素２Ｂをセル缶１０の内壁面１０ｂ、１０ｂに押し付けて保持する。 In order for the expansion force absorber 4 to exert the function of pressing and holding the first battery element 2A and the second battery element 2B in this manner, the expansion force absorber 4 must be placed inside the cell can 10 in a crushed state. A storage method can be adopted. That is, as shown in FIG. 7, first, the expansion force absorber 4 is laminated between the first battery element 2A and the second battery element 2B, to which the sealing member 11 is attached in advance, so as to sandwich the expansion force absorber 4 therebetween. Next, by compressing the first battery element 2A and the second battery element 2B from both sides in the thickness direction (D2 direction), the expansion force absorber 4 is crushed in the thickness direction, and the first battery element The expansion force absorber 4 is inserted into the cell can 10 together with 2A and the second battery element 2B. After that, when the expansion force absorber 4 expands inside the cell can 10 due to elastic restoring force and swelling, the expansion force absorber 4 moves the first battery element 2A and the second battery element 2B to the inner wall surface 10b of the cell can 10 . , 10b.

なお、この場合のセル缶１０の厚さ方向（Ｄ２方向）の幅は、膨張力吸収体４の膨張による押し付け力を発揮させるため、第１電池要素２Ａ、膨張力吸収体４及び第２電池要素２Ｂからなる積層体の圧縮前の厚さ方向（Ｄ２方向）の幅よりも小さく設定される。しかし、セル缶１０の内部に挿入する際に、膨張力吸収体４が押し潰されて変形するため、第１電池要素２Ａ、膨張力吸収体４及び第２電池要素２Ｂからなる積層体をセル缶１０の内部に容易に挿入でき、蓄電セル１の組立て性が向上する効果が得られる。 In this case, the width of the cell can 10 in the thickness direction (D2 direction) is set to the first battery element 2A, the expansion force absorber 4, and the second battery in order to exert the pressing force due to the expansion of the expansion force absorber 4. It is set smaller than the width in the thickness direction (D2 direction) before compression of the laminate composed of the element 2B. However, since the expansion force absorber 4 is crushed and deformed when it is inserted into the cell can 10, the laminate composed of the first battery element 2A, the expansion force absorber 4, and the second battery element 2B is It can be easily inserted into the can 10, and the effect of improving the assemblability of the storage cell 1 is obtained.

蓄電セル１における第１電池要素２Ａ及び第２電池要素２Ｂは、電解液が不要な全固体電池からなる電池要素とすることもできるが、本実施形態のようにセル缶１０内に電解液が収納される場合、膨張力吸収体４は、図８に示すように、不透液性フィルム５内に封入されていてもよい。これにより、膨張力吸収体４への電解液の接触や滲み込みがなくなるため、膨張力吸収体４の変質や特性変化が防止され、電池要素の膨張力の吸収作用を長期に安定化させることができる。また、セル缶１０内の電解液を第１電池要素２Ａ及び第２電池要素２Ｂの部分に限定して含浸させることができるため、電解液の使用量を削減でき、低コスト化も可能となる。 The first battery element 2A and the second battery element 2B in the storage cell 1 may be battery elements composed of an all-solid battery that does not require electrolyte. When stored, the expansive force absorber 4 may be enclosed in a liquid-impermeable film 5 as shown in FIG. As a result, the electrolytic solution does not come into contact with or seep into the expansion force absorber 4, so that the expansion force absorber 4 is prevented from deteriorating or changing in characteristics, and the expansion force absorbing function of the battery element can be stabilized for a long period of time. can be done. In addition, since the electrolytic solution in the cell can 10 can be impregnated only in the first battery element 2A and the second battery element 2B, the amount of electrolytic solution used can be reduced, and the cost can be reduced. .

不透液性フィルム５としては、不透液性で電解液に侵されない性質を有するフィルムであれば特に制限なく使用することができる。一般には、ポリエチレン等の樹脂フィルムが用いられるが、樹脂と金属とが積層一体化されたラミネートフィルムであってもよい。 As the liquid-impermeable film 5, any film can be used without any particular limitation as long as it is liquid-impermeable and has properties not to be eroded by the electrolytic solution. Generally, a resin film such as polyethylene is used, but a laminate film in which a resin and a metal are laminated and integrated may be used.

膨張力吸収体４が膨潤性を有する構造体である場合は、図９に示すように、膨張力吸収体４を液体Ｗと共に不透液性フィルム５内に封入してもよい。不透液性フィルム５内の液体Ｗによって膨張力吸収体４を膨潤させることができるため、電解液の注液を待たずに、初期から電池要素の膨張力の吸収作用を良好に発揮させることができる。また、液体Ｗの量を適宜調整することにより、膨張力吸収体４の膨潤量を調整することも可能である。なお、液体Ｗは、膨張力吸収体４を膨潤させ得るだけの量で封入されるものであり、膨張力吸収体４の膨張力吸収作用に影響を与えることはない。 When the expansive force absorber 4 is a swellable structure, the expansive force absorber 4 may be sealed together with the liquid W in the liquid-impermeable film 5 as shown in FIG. Since the expansion force absorber 4 can be swollen by the liquid W in the liquid-impermeable film 5, the expansion force absorption function of the battery element can be satisfactorily exhibited from the beginning without waiting for the injection of the electrolytic solution. can be done. Further, by appropriately adjusting the amount of the liquid W, it is also possible to adjust the amount of swelling of the expansive force absorber 4 . The liquid W is enclosed in an amount sufficient to swell the expansive force absorber 4 and does not affect the expansive force absorbing function of the expansive force absorber 4 .

液体Ｗとしては、電解液から添加剤を除去した液体、又は、電解液とは別の液体を使用することができる。電解液よりも安価な液体（例えば有機溶媒）を使用することにより、低コスト化が可能である。また、液体Ｗとして不活性溶媒を使用する場合には、安全性を更に向上させることができる。なお、液体Ｗと共に不透液性フィルム５内に封入された膨潤性を有する膨張力吸収体４は、第１電池要素２Ａ及び第２電池要素２Ｂが全固体電池からなる電池要素である場合にも適用可能である。 As the liquid W, a liquid obtained by removing the additive from the electrolytic solution or a liquid different from the electrolytic solution can be used. Cost reduction is possible by using a liquid (for example, an organic solvent) that is cheaper than the electrolytic solution. Moreover, when an inert solvent is used as the liquid W, the safety can be further improved. Note that the expansion force absorber 4 having a swelling property enclosed in the liquid-impermeable film 5 together with the liquid W can be is also applicable.

膨張力吸収体４は、上述のように第１吸収体４１と第２吸収体４２とで剛性を異ならせることに代えて、図１０に示す膨張力吸収体４のように、第１吸収体４３と第２吸収体４４とで厚さを異ならせてもよい。即ち、封口体１１側に配置される第１吸収体４３の厚さは、第２吸収体４４の厚みに比較して小さく形成される。これにより、第１電池要素２Ａ及び第２電池要素２Ｂは、セル缶１０の高さ方向の中央部よりも封口体１１側で、内壁面１０ｂ側よりも膨張力吸収体４側に膨張し易くなり、剛性を異ならせる場合と同様の効果が得られる。 In the expansive force absorber 4, instead of having the first absorber 41 and the second absorber 42 differ in rigidity as described above, the expansive force absorber 4 has the first absorber 4 as shown in FIG. 43 and the second absorbent body 44 may have different thicknesses. That is, the thickness of the first absorbent body 43 arranged on the sealing body 11 side is formed to be smaller than the thickness of the second absorbent body 44 . As a result, the first battery element 2A and the second battery element 2B are more likely to expand toward the sealing body 11 side than the center portion in the height direction of the cell can 10 and toward the expansion force absorber 4 side rather than the inner wall surface 10b side. , and the same effect as in the case of different rigidity can be obtained.

第１吸収体４３及び第２吸収体４４にも、上述した弾性体や膨潤性を有する構造体を使用することができる。第１吸収体４３と第２吸収体４４とは、厚さが異なるものであれば、同じ材質でも異なる材質でもよいが、厚さを異ならせることによる封口体１１側の膨張力吸収効果を損なうことのないように、第１吸収体４３と第２吸収体４４との剛性は略同一であることが望ましい。 For the first absorbent body 43 and the second absorbent body 44 as well, the above-described elastic bodies and structures having swelling properties can be used. The first absorbent body 43 and the second absorbent body 44 may be made of the same material or different materials as long as they have different thicknesses. It is desirable that the rigidity of the first absorbent body 43 and that of the second absorbent body 44 are substantially the same so as to prevent this.

また、膨張力吸収体４の厚さを異ならせる場合は、図１１に示すように、第１電池要素２Ａ及び第２電池要素２Ｂの高さに対応する高さで一体に形成されたものであってもよい。この場合の膨張力吸収体４は、セル缶１０の高さ方向の中央部よりも封口体１１寄りの部位４ｂよりも上方の厚さを、当該部位４ｂよりも下方の厚さよりも小さく形成される。図１１に示す膨張力吸収体４は、上方側が次第に細くなるテーパー状に形成されているが、特にテーパー状とするものに制限されない。また、このように厚さを異ならせた膨張力吸収体４も、図８及び図９に示した膨張力吸収体４と同様に、不透液性フィルム５内に封入されてもよい。更に、厚さを異ならせた膨張力吸収体４も、押し潰してセル缶１０内に収納することにより、セル缶１０の内部で第１電池要素２Ａ及び第２電池要素２Ｂをセル缶１０の内壁面１０ｂ、１０ｂに押し付けて保持するようにしてもよい。 Moreover, when the thickness of the expansion force absorber 4 is made different, as shown in FIG. There may be. In this case, the expansive force absorber 4 is formed such that the thickness above the portion 4b closer to the sealing member 11 than the central portion in the height direction of the cell can 10 is smaller than the thickness below the portion 4b. be. The expansive force absorber 4 shown in FIG. 11 is formed in a tapered shape that gradually narrows on the upper side, but is not particularly limited to a tapered shape. Moreover, the expansive force absorbers 4 having such different thicknesses may also be enclosed in the liquid-impermeable film 5 in the same manner as the expansive force absorbers 4 shown in FIGS. Furthermore, the expansion force absorbers 4 having different thicknesses are also crushed and accommodated in the cell can 10, so that the first battery element 2A and the second battery element 2B are separated from each other inside the cell can 10. It may be held by being pressed against the inner wall surfaces 10b, 10b.

以上のように構成される蓄電セル１は、通常、厚さ方向（Ｄ２方向）に複数積層されることによりモジュール化される。モジュール化された蓄電セル１は、その側面（Ｄ１方向に面する側面）又は底面を、ヒートシンクや温調デバイスに押し付けるように設置される。この場合、セル缶１０を熱伝導部材として利用できるため、伝熱プレートが不要であり、部品点数を削減できてコストの低減が可能である。 The storage cell 1 configured as described above is usually modularized by stacking a plurality of cells in the thickness direction (D2 direction). The modularized storage cell 1 is installed so that the side surface (the side surface facing the D1 direction) or the bottom surface thereof is pressed against a heat sink or a temperature control device. In this case, since the cell can 10 can be used as a heat-conducting member, a heat-conducting plate is not required, and the number of parts can be reduced, thereby reducing the cost.

分割構造の膨張力吸収体４は、第１吸収体４１、４３と第２吸収体４２、４４とに２分割されるものに制限されない。例えば、膨張力吸収体４は、セル缶１０の高さ方向の中央部と、中央部よりも上方の封口体１１側と、中央部よりも下方の底部１０ｃ側と、に３分割されてもよい。この場合、中央部よりも下方の底部１０ｃ側の吸収体も、封口体１１側の吸収体と同様に、剛性を低く又は厚さを小さくしてもよい。 The expansive force absorber 4 having a split structure is not limited to one that is split into the first absorbers 41 and 43 and the second absorbers 42 and 44 . For example, the expansive force absorber 4 may be divided into three parts: the central portion in the height direction of the cell can 10, the sealing member 11 side above the central portion, and the bottom portion 10c side below the central portion. good. In this case, the absorber on the side of the bottom portion 10c below the central portion may also have low rigidity or a small thickness, like the absorber on the side of the sealing member 11. FIG.

また、セル缶１０内に収納される電池要素は１つだけでもよい。この場合、膨張力吸収体４は、セル缶１０の一方の内壁面１０ｂと電池要素との間に配置される。 Also, only one battery element may be housed in the cell can 10 . In this case, the expansion force absorber 4 is arranged between one inner wall surface 10b of the cell can 10 and the battery element.

１蓄電セル
２Ａ第１電池要素
２Ｂ第２電池要素
４膨張力吸収体
５不透液性フィルム
１０セル缶
１０ａ開口部
１０ｂ内壁面
１１封口体
REFERENCE SIGNS LIST 1 storage cell 2A first battery element 2B second battery element 4 expansion force absorber 5 liquid-impermeable film 10 cell can 10a opening 10b inner wall surface 11 sealing member

Claims

A storage cell in which a battery element and an electrolytic solution are housed inside a cell can, and an upper opening of the cell can is sealed with a sealing member,
a sheet-like expansion force absorber capable of absorbing the expansion force of the battery element by compressing the expansion force of the battery element inside the cell can;
The battery element is a non-wound battery element having a laminated structure in which a positive electrode plate and a negative electrode plate are alternately laminated via a separator. and the inner wall surface of the cell can, respectively ,
The power storage cell, wherein the expansive force absorber is made of an elastic body, which is a foam, or a structural body having swelling properties, and is enclosed in a liquid-impermeable film.

The electric storage cell according to claim 1 , wherein the structure having swelling property is a swelling resin or a resin fiber assembly.

3. The storage cell according to claim 1 , wherein said swellable structure is enclosed in said liquid-impermeable film together with a liquid.

The storage cell according to claim 3 , wherein the liquid is a liquid obtained by removing an additive from the electrolytic solution, or a liquid different from the electrolytic solution.

5. The expansion force absorber according to any one of claims 1 to 4 , wherein the expansion force absorber expands in the thickness direction inside the cell can to press and hold the battery element against the inner wall surface of the cell can. storage cells.

Two battery elements are housed inside the cell can,
The storage cell according to any one of claims 1 to 5 , wherein said expansion force absorber is sandwiched between said two battery elements.

7. The storage cell of claim 6 , wherein two said battery elements are connected in series inside said cell can.