Patent Description:
Conventionally, <CIT> discloses a rechargeable battery. The rechargeable battery includes an electrode assembly, a case, a cap plate, a first sub-terminal, and a second sub-terminal. The cap plate seals an opening of the case. The first sub-terminal is arranged on one end of the cap plate, and extends adjacent to an outer surface of the case. The second sub-terminal is on the other end of the cap plate, and extends adjacent to another outer surface of the case.

In the rechargeable battery (i.e., the power storage cell) disclosed in <CIT>, in order to reduce the height of the power storage module, the external terminals (i.e., the sub-terminals) of adjacent power storage cells are electrically connected to each other by a bus bar or the like on a side surface of the case. However, it is not easy to arrange the bus bar or the like with respect to the external terminal on the side surface of the case <CIT> discloses a battery module with a plurality of cells wherein the external terminal is disposed on a side surface of the case, and a recessed section id formed on a side surface adjacent to the side surface provided with the external terminal.

The present disclosure has been accomplished in view of the aforementioned problem, and it is therefore an object of the present disclosure to provide a power storage cell and a power storage module which allows an easy arrangement of a component such as a bus bar for connecting power storage cells to each other.

The power storage cell according to the present invention is given in the claims and includes an electrode assembly, a cell case, and an external terminal. The cell case houses an electrode assembly. The external terminal is fixed to the cell case. The external terminal includes a first terminal portion and a second terminal portion. The first terminal portion is arranged above the cell case. The second terminal portion extends from the first terminal portion along the side surface of the cell case. The second terminal portion is provided with a recess. The recess is formed on a surface of the second terminal portion opposite to the other surface thereof that faces the cell case.

A power storage module according to an embodiment of the present invention is also given in the claims and includes two or more power storage cells, a band, and a bus bar. The two or more power storage cells are arranged side by side in the lateral direction. The band surrounds the two or more power storage cells. The bus bar is disposed in the recess of a first power storage cell which is one of the two or more power storage cells and in the recess of a second power storage cell which is another one of the two or more power storage cells and is adjacent to the first power storage cell. The bus bar is provided on a surface of the band that faces the power storage cell.

Embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding members are denoted by the same reference numerals.

<FIG> is a perspective view schematically illustrating a power storage module <NUM> according to an embodiment of the present disclosure. <FIG> is another perspective view schematically illustrating the power storage module <NUM> according to the embodiment of the present disclosure. As illustrated in <FIG>, the power storage module <NUM> according to an embodiment of the present disclosure includes two or more power storage cells <NUM>, a band <NUM>, and one or more bus bars <NUM>.

The two or more power storage cells <NUM> are arranged side by side in the lateral direction. Specifically, two or more power storage cells <NUM> are arranged side by side in the thickness direction of the power storage cell <NUM>. A spacer (not illustrated) may be disposed between a pair of power storage cells <NUM> adjacent to each other.

First, the configuration of the power storage cell <NUM> will be described in detail. <FIG> is a perspective view schematically illustrating the power storage cell according to an embodiment of the present disclosure. <FIG> is a cross-sectional view of the power storage module taken along line IV-IV in <FIG>.

As illustrated in <FIG> and <FIG>, the power storage cell <NUM> includes an electrode assembly <NUM>, a cell case <NUM>, a pair of external terminals <NUM>, a pair of connecting members <NUM>, and an insulating member <NUM>.

<FIG> is a cross-sectional view of the electrode assembly taken along line V-V in <FIG>. As illustrated in <FIG>, the electrode assembly <NUM> includes a plurality of electrodes <NUM> and <NUM>, and a separator <NUM>.

As illustrated in <FIG>, the plurality of electrodes <NUM> and <NUM> are arranged side by side in one direction (the lateral direction in <FIG>). The plurality of electrodes <NUM> and <NUM> include a plurality of positive electrodes <NUM> and a plurality of negative electrodes <NUM>.

Each positive electrode <NUM> is formed in a rectangular shape elongated in a width direction (a direction orthogonal to both the one direction and the vertical direction). Each positive electrode <NUM> includes a positive electrode collector foil <NUM> and a positive electrode active material layer <NUM> provided on both surfaces of the positive electrode collector foil <NUM>. The positive electrode collector foil <NUM> includes a positive electrode tab 112p (see <FIG>) on which the positive electrode active material layer <NUM> is not provided. The positive electrode tab 112p protrudes toward one side of the width direction (a direction orthogonal to the paper surface of <FIG>).

Each negative electrode <NUM> is formed in a rectangular shape elongated in the width direction. Each negative electrode <NUM> includes a negative electrode collector foil <NUM> and a negative electrode active material layer <NUM> provided on both surfaces of the negative electrode collector foil <NUM>. As illustrated in <FIG>, the negative electrode collector foil <NUM> includes a negative electrode tab 122n (see <FIG>) on which the negative electrode active material layer <NUM> is not provided. The negative electrode tab 122n protrudes toward the other side of the width direction.

The separator <NUM> insulates the positive electrode <NUM> and the negative electrode <NUM> from each other. The separator <NUM> is made of an insulating material, and has minute voids that allow ions to pass through. As illustrated in <FIG>, the separator <NUM> is formed in a zigzag shape.

The separator <NUM> has a rectangular shape before being formed in a zigzag shape. The separator <NUM> is formed in a zigzag shape and is arranged between the electrodes <NUM> and <NUM>. The separator <NUM> includes a plurality of intervening portions 132a, a plurality of upper folded portions 132b, a plurality of lower folded portions 132c, and an outermost covering portioning portion 132d.

Each intervening portion 132a is interposed between a pair of electrodes <NUM> and <NUM> adjacent to each other in the one direction. In other words, each intervening portion 132a functions to insulate the positive electrode <NUM> and the negative electrode <NUM> from each other. Each intervening portion 132a is formed in a rectangular shape.

Each upper folded portion 132b connects an upper end of one intervening portion 132a of the plurality of intervening portions 132a to an upper end of another intervening portion 132a of the plurality of intervening portions 132a which is adjacent to the one intervening portion 132a on one side of the one direction. In the present embodiment, the upper folded portion 132b is disposed above the positive electrode <NUM>.

Each lower folded portion 132c connects a lower end of one intervening portion 132a of the plurality of intervening portions 132a to a lower end of another intervening portion 132a of the plurality of intervening portions 132a which is adjacent to the one intervening portion 132a on the other side of the one direction. In the present embodiment, the lower folded portion 132c is disposed below the negative electrode <NUM>. In other words, the negative electrode <NUM> is disposed above the lower folded portion 132c.

The outermost covering portioning portion 132d collectively covers each upper folded portion 132b and each lower folded portion 132c. More specifically, the outermost covering portioning portion 132d collectively covers all of the electrodes <NUM> and <NUM>, all of the intervening portions 132a, all of the upper folded portions 132b and all of the lower folded portions 132c while being wound around a central axis parallel to the width direction. A terminal end 132e of the outermost covering portioning portion 132d is configured not to overlap with the positive electrode active material layer <NUM> and the negative electrode active material layer <NUM> in the one direction. In the present embodiment, the terminal end 132e of the outermost covering portioning portion 132d is provided below each of the electrodes <NUM> and <NUM>. The peripheral surface and bottom surface of the plurality of electrodes <NUM> and <NUM> and the separator <NUM> are covered with an insulating film (not illustrated).

As illustrated in <FIG> and <FIG>, the cell case <NUM> houses the electrode assembly <NUM>. The cell case <NUM> contains an electrolytic solution (not illustrated). The cell case <NUM> is sealed. The cell case <NUM> includes a case body <NUM> and a lid <NUM>.

The case body <NUM> has an opening that opens upward. The case body <NUM> is made of a metal such as aluminum. The case body <NUM> includes a bottom wall <NUM> and a peripheral wall <NUM>. The bottom wall <NUM> is formed in a rectangular flat plate shape. The peripheral wall <NUM> rises from the bottom wall <NUM>. The peripheral wall <NUM> is formed in a quadrangular cylindrical shape. The length of the peripheral wall <NUM> in the width direction is longer than the length of the peripheral wall <NUM> in the thickness direction. The length of the peripheral wall <NUM> in the height direction is longer than the length of the peripheral wall <NUM> in the thickness direction.

The lid <NUM> closes the opening of the case body <NUM>. The lid <NUM> is connected to the opening by welding or the like. The lid <NUM> is formed in a flat plate shape. The lid <NUM> is made of a metal such as aluminum. The lid <NUM> includes a pressure release valve <NUM> and a sealing member <NUM>.

The pressure release valve <NUM> is formed at a central portion of the lid <NUM>. The pressure release valve <NUM> is configured to break when the internal pressure of the cell case <NUM> becomes equal to or higher than a predetermined pressure. When the pressure release valve <NUM> is broken, the gas in the cell case <NUM> is released to the outside of the cell case <NUM> through the pressure release valve <NUM>, which reduces the internal pressure of the cell case <NUM>.

The sealing member <NUM> seals a liquid injection port h formed in the lid <NUM>. The liquid injection port h is a through hole for injecting an electrolytic solution into the cell case <NUM> in the manufacturing process of the power storage cell <NUM>. After the electrolytic solution is injected into the case body <NUM> through the liquid injection port h, the liquid injection port h is sealed by the sealing member <NUM>.

The pair of external terminals <NUM> is fixed to the cell case <NUM>. One of the pair of external terminals <NUM> is a positive external terminal, and the other is a negative external terminal. Each external terminal <NUM> is fixed to an upper surface of the lid <NUM> via an upper insulating portion <NUM> which will be described later. Each external terminal <NUM> is made of a metal such as aluminum.

Each external terminal <NUM> includes a first terminal portion <NUM> and a second terminal portion <NUM>. The first terminal portion <NUM> is arranged above the cell case <NUM>. More specifically, the first terminal portion <NUM> is fixed to the upper surface of the lid <NUM> via the upper insulating portion <NUM>. The first terminal portion <NUM> is formed, for example, in a rectangular parallelepiped shape.

The second terminal portion <NUM> extends from the first terminal portion <NUM> along a side surface of the cell case <NUM>. More specifically, the second terminal portion <NUM> extends along the peripheral wall <NUM> in the thickness direction of the case body <NUM>.

The second terminal portion <NUM> is provided with a recess <NUM>. The recess <NUM> is formed on a surface of the second terminal portion <NUM> opposite to the other surface thereof that faces the cell case <NUM> (the case body <NUM>). The recess <NUM> extends from one end edge <NUM> to the other end edge <NUM> in the lateral direction of the second terminal portion <NUM> when viewed from the direction (i.e., the width direction) in which the second terminal portion <NUM> and the cell case <NUM> (the case body <NUM>) are arranged in line (see <FIG>).

The pair of connecting members <NUM> connects a plurality of electrode tabs 112p and a plurality of electrode tabs 122n to the pair of external terminals <NUM>, respectively. More specifically, one of the pair of connecting members <NUM> connects the plurality of positive electrode tabs 112p to the positive external terminal300, and the other connecting member <NUM> connects the plurality of negative electrode tabs 122n to the negative external terminal <NUM>. Since the pair of connecting members <NUM> have substantially the same structure, only one connecting member <NUM> will be described below.

The connecting member <NUM> includes a collector tab <NUM>, a subtab <NUM>, and a connecting pin <NUM>.

The collector tab <NUM> has a side portion <NUM> and an upper portion <NUM>. The side portion <NUM> is arranged on a side surface of the electrode assembly <NUM> in the width direction. The upper portion <NUM> is arranged above an upper surface of the electrode assembly <NUM>. The upper portion <NUM> extends inward in the width direction from an upper end of the side portion <NUM>.

The subtab <NUM> connects the plurality of positive electrode tabs 112p to the collector tab <NUM>. One end <NUM> of the subtab <NUM> is connected to the plurality of positive electrode tabs 112p by welding or the like, and the other end <NUM> of the subtab <NUM> is connected to the side portion <NUM> of the collector tab <NUM> by welding or the like.

The connecting pin <NUM> connects the collector tab <NUM> to the first terminal portion <NUM> of the external terminal <NUM>. The connecting pin <NUM> connects the upper portion <NUM> to the first terminal portion <NUM> of the external terminal <NUM>. Specifically, the lower end of the connecting pin <NUM> is inserted into a through hole provided on the upper portion <NUM> and is connected to the upper portion <NUM> by welding or the like, and the upper end of the connecting pin <NUM> is inserted into a through hole provided on the first terminal portion <NUM> of the external terminal <NUM> and is connected to the external terminal <NUM> by welding, caulking or the like.

The insulating member <NUM> insulates the cell case <NUM> and the connecting member <NUM> from each other. The insulating member <NUM> includes an upper insulating portion <NUM>, a lateral insulating portion <NUM>, a lower insulating portion <NUM>, an insulating cylinder <NUM>, and an insulating plate <NUM>.

The upper insulating portion <NUM> is fixed to the upper surface of the lid <NUM>. The upper insulating portion <NUM> is disposed between the lid <NUM> and the first terminal portion <NUM> of the external terminal <NUM>. The upper insulating portion <NUM> is provided with an insertion hole through which the connecting pin <NUM> is inserted.

The lateral insulating portion <NUM> is disposed on the peripheral wall <NUM> of the case body <NUM>. The lateral insulating portion <NUM> extends downward from the upper insulating portion <NUM>. The lateral insulating portion <NUM> is disposed between the peripheral wall <NUM> of the case body <NUM> and the second terminal portion <NUM> of the external terminal <NUM>.

The lower insulating portion <NUM> is fixed to the lower surface of the lid <NUM>. The lower insulating portion <NUM> is disposed between the lid <NUM>, and the upper portion <NUM> and a lower portion of the connecting pin <NUM>. The lower insulating portion <NUM> is provided with an insertion hole through which the connecting pin <NUM> is inserted.

The insulating cylinder <NUM> is disposed between the connecting pin <NUM> and the lid <NUM>. The insulating cylinder <NUM> is formed in a cylindrical shape, and is configured to surround the connecting pin <NUM>.

The insulating plate <NUM> is fixed to the lower surface of the upper portion <NUM>. The insulating plate <NUM> is disposed on the electrode assembly <NUM>. A through hole is formed in a portion of the insulating plate <NUM> located below the pressure release valve <NUM> and a portion of the insulating plate <NUM> located below the liquid injection port h.

The insulating member <NUM> insulating one connecting member <NUM> (for example, the connecting member <NUM> electrically connected to the positive tab 112p) of the pair of connecting members <NUM> and the cell case <NUM> may not include the upper insulating section <NUM> and the lateral insulating section <NUM>. In this case, the external terminal <NUM> may be in direct contact with the cell case <NUM>, or a conductive member may be disposed between the external terminal <NUM> and the cell case <NUM> instead of the upper insulating portion <NUM> and the lateral insulating portion <NUM>.

Next, the band <NUM> and the bus bar <NUM> of the power storage module <NUM> will be described. <FIG> is a perspective view schematically illustrating a step of attaching a band to a plurality of power storage cells.

As illustrated in <FIG>, <FIG> and <FIG>, the band <NUM> is configured to surround two or more power storage cells <NUM>. The band <NUM> extends in a circular shape along the lateral direction orthogonal to the vertical direction. The band <NUM> has a belt-like profile.

The band <NUM> is stretchable. The band <NUM> surrounds the power storage cells <NUM> in a stretched state. When the band <NUM> surrounds the power storage cells <NUM>, the band <NUM> restrains two or more power storage cells <NUM> by a contracting force. The band <NUM> is configured to further stretch from the state of surrounding the power storage cells <NUM>. The material of the band <NUM> is not particularly limited. The band <NUM> may be made of an elastic material such as silicone rubber.

In the present embodiment, the band <NUM> is constituted by one band member formed in a circular shape. However, the band <NUM> may be formed in a circular shape by connecting both ends of a belt member to each other. In other words, the band <NUM> may have a connection portion formed by connecting both ends to each other.

The band <NUM> may be constituted by two or more belt members. In this case, the band <NUM> may be formed in a circular shape by connecting the ends of adjacent belt members to each other. In other words, the band <NUM> may have two or more connection portions formed by connecting the ends of two or more belt members to each other.

In the connection portion, the belt members constituting the band <NUM> may be separable from each other. The length of the band <NUM> in the circular direction may be adjustable at the connection portion. This makes it possible to easily modify the design of the band <NUM> when the shape of the power storage cells <NUM> or the number of the power storage cells <NUM> is changed. The connection portion may be configured as a belt buckle which allows to adjust the length of the band <NUM>.

The bus bar <NUM> (the first bus bar 30A) is disposed in the recess <NUM> of a first power storage cell 10A which is one of the two or more power storage cells <NUM> and in the recess <NUM> of a second power storage cell 10B which is another one of the two or more power storage cells <NUM> and is adjacent to the first power storage cell 10A.

The bus bar <NUM> is electrically conductive. Therefore, the bus bar <NUM> electrically connects the external terminal <NUM> of the first power storage cell 10A and the external terminal <NUM> of the second power storage cell 10B. The bus bar <NUM> is made of a metal such as aluminum or an aluminum alloy. The bus bar <NUM> may be connected to the external terminals <NUM> by welding or the like.

In the present embodiment, the two or more power storage cells <NUM> further include a third power storage cell 10C. The one or more bus bars <NUM> further include a second bus bar 30B different from the first bus bar 30A.

The third power storage cell 10C is disposed on one side of the first power storage cell 10A opposite to the side where the second power storage cell 10B is disposed. The third power storage cell 10C is adjacent to the first power storage cell 10A. The second bus bar 30B is disposed in the recess <NUM> provided on the other side surface of the first power storage cell 10A and in the recess <NUM> of the third power storage cell 10C.

The bus bar <NUM> is provided on a surface of the band <NUM> that faces the power storage cell <NUM>. A portion of the bus bar <NUM> is embedded in the band <NUM>.

In the present embodiment, either the first bus bar 30A or the second bus bar 30B is provided on a surface of the band <NUM> that faces the power storage cell <NUM>. More specifically, all the bus bars <NUM> positioned on the inner peripheral side of the band <NUM> are provided on the surface of the band <NUM> that faces the power storage cell <NUM>. These bus bars <NUM> are fixed on the surface of the band <NUM>. The bus bars <NUM> are spaced apart from each other on the surface of the band <NUM>.

As described above, in the power storage cell <NUM> according to the embodiment of the present disclosure, the second terminal portion <NUM> is provided with a recess <NUM>. The recess <NUM> is formed on a surface of the second terminal portion <NUM> opposite to the other surface thereof that faces the cell case <NUM>.

According to the above configuration, the position of the bus bar <NUM> with respect to the external terminal <NUM> may be determined by placing the bus bar <NUM> in the recess <NUM>. Therefore, it is possible to easily determine the position of a component such as the bus bar for connecting the power storage cells <NUM> to each other.

The recess <NUM> extends from one end edge <NUM> to the other end edge <NUM> in the lateral direction of the second terminal portion <NUM> when viewed from the direction in which the second terminal portion <NUM> and the cell case <NUM> are arranged in line.

According to the above configuration, the bus bar <NUM> is slidable in the recess <NUM> in the thickness direction of the cell case <NUM>. Therefore, it is possible to easily adjust the position of a component such as the bus bar <NUM> with respect to the second terminal portion <NUM> in the vertical direction, and it is possible to easily adjust the position of a component such as the bus bar <NUM> with respect to the second terminal portion <NUM> in the lateral direction. Therefore, it is possible to easily connect the power storage cells <NUM> to each other.

The power storage module <NUM> according to an embodiment of the present disclosure includes two or more power storage cells <NUM>, a band <NUM>, and a bus bar <NUM>. The two or more power storage cells <NUM> are arranged side by side in the lateral direction. The band <NUM> surrounds two or more power storage cells <NUM>. The bus bar <NUM> is disposed in the recess <NUM> of the first power storage cell 10A, which is one of the two or more power storage cells <NUM>, and in the recess <NUM> of the second power storage cell 10B, which is another one of the two or more power storage cells <NUM> and is adjacent to the first power storage cell 10A. The bus bar <NUM> is provided on a surface of the band <NUM> that faces the power storage cell <NUM>.

According to the above configuration, it is possible to reduce the height of the power storage module <NUM> as compared with the case where the external terminals <NUM> are connected to each other by the bus bar on the upper surface of the external terminal <NUM>. Further, by attaching the band <NUM> to the plurality of power storage cells <NUM> in the vertical direction (see <FIG>), it is possible to easily dispose the bus bar <NUM> in each recess <NUM>. Therefore, it is possible to easily connect the power storage cells <NUM> to each other.

The band <NUM> is stretchable. According to this configuration, it is possible to restrain the plurality of power storage cells <NUM> by a contracting force of the band <NUM>. Further, by restraining the power storage cell <NUM> with the band <NUM>, it is possible to fix the bus bar <NUM> in the recess <NUM> before welding or without the need of welding the bus bar <NUM> to the external terminal <NUM>. Further, by stretching the band <NUM>, it is possible to easily detach the bus bar <NUM> from the recess <NUM>. Therefore, it is possible to easily connect the power storage cells <NUM> to each other.

Claim 1:
A power storage cell comprising:
an electrode assembly (<NUM>);
a cell case (<NUM>) that houses the electrode assembly (<NUM>); and
an external terminal (<NUM>) that is fixed to the cell case (<NUM>),
wherein the external terminal (<NUM>) includes a first terminal portion (<NUM>) that is arranged above the cell case (<NUM>), and a second terminal portion (<NUM>) that extends from the first terminal portion (<NUM>) along a side surface of the cell case (<NUM>),
the second terminal portion (<NUM>) is provided with a recess (<NUM>) on a surface of the second terminal portion (<NUM>) opposite to the other surface thereof that faces the cell case (<NUM>).