JP7172576B2 - assembled battery - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to an assembled battery, and more particularly to an assembled battery mounted on a vehicle.

An assembled battery is formed by arranging a plurality of unit cells side by side, and electrode terminals of adjacent unit cells are connected to each other by bus bars. The distance between the electrode terminals varies when the unit cell expands or contracts due to charging and discharging with a large current.

In Japanese Patent Application Laid-Open No. 2015-138620 (Patent Document 1), in order to relieve the stress applied to the busbar when the distance between the electrode terminals varies, the busbar bulges away from the unit cell. is provided as follows.

JP 2015-138620 A

In the bus bar disclosed in Patent Literature 1, the joints to be joined to the electrode terminals are provided so as to cover the electrode terminals. Depending on the installation position of the electrode terminal, the area where the busbar and the electrode terminal overlap becomes small, and there may be a case where only a part of the busbar can be joined to the electrode terminal. When the bonding area is reduced in this way, there is concern that the busbar disclosed in Patent Document 1 may not be able to sufficiently disperse the stress.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide an assembled battery capable of dispersing stress applied to bus bars.

An assembled battery based on the present disclosure includes a plurality of unit cells arranged side by side in an arrangement direction, a first electrode terminal of one of the adjacent unit cells, and one of the adjacent unit cells. and a bus bar that electrically connects the second electrode terminal of the other unit cell. The busbar includes a first end and a second end that are both ends of the busbar in a width direction orthogonal to a length direction parallel to the arrangement direction. The first end portion includes a first joint portion joined to the first electrode terminal, a second joint portion joined to the second electrode terminal, the first joint portion and the second joint portion. and a connecting portion for connecting the The connecting portion has a curved portion that is recessed toward the second end portion when viewed from above in a direction orthogonal to the length direction and the width direction.

In the above configuration, for example, when the distance between the cells adjacent to each other increases, force is applied to the busbar along the length direction. At this time, the first end has a curved portion that curves so as to be depressed toward the second end when the connecting portion is viewed from above, so that the force applied along the length direction is reduced to the width. distributed in the direction. Thereby, even when the first end side is connected to the first and second electrode terminals, it is possible to suppress concentration of stress on the first end side.

According to the present disclosure, it is possible to provide an assembled battery capable of relaxing the stress applied to the busbar.

1 is a plan view of an assembled battery according to Embodiment 1. FIG. 2 is an enlarged plan view showing the periphery of the bus bar shown in FIG. 1; FIG. FIG. 2 is a cross-sectional view taken along line III-III shown in FIG. 1; FIG. 4 is an enlarged plan view showing the periphery of a bus bar provided in an assembled battery in a comparative example; FIG. 10 is a diagram showing the distribution of stress applied to the busbar when the distance between adjacent cells increases in the assembled battery of the comparative example. 5 is a diagram showing the distribution of stress applied to the busbar when the distance between adjacent cells increases in the assembled battery according to Embodiment 1. FIG. FIG. 8 is an enlarged plan view showing the periphery of a busbar provided in the assembled battery according to the second embodiment; FIG. 11 is an enlarged plan view showing the periphery of a bus bar provided in the assembled battery according to Embodiment 3; FIG. 11 is an enlarged plan view showing the periphery of a busbar provided in an assembled battery according to Embodiment 4; FIG. 11 is a cross-sectional view of an assembled battery according to Embodiment 5; FIG. 11 is a cross-sectional view of an assembled battery according to Embodiment 6;

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments shown below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

(Embodiment 1)
FIG. 1 is a plan view of an assembled battery according to Embodiment 1. FIG. An assembled battery 1 according to Embodiment 1 will be described with reference to FIG.

The assembled battery 1 is mounted in vehicles such as hybrid vehicles and electric vehicles. As shown in FIG. 1, the assembled battery 1 is configured by connecting a plurality of chargeable/dischargeable single cells 10 in series. In the assembled battery 1 , a plurality of single cells 10 having the same shape are connected in series to form the assembled battery 1 . In addition, the number of cells 10 constituting the assembled battery 1 is not particularly limited.

Each unit cell 10 is arranged in a predetermined arrangement direction (arrow AR direction in FIG. 1) at a distance from each other. A plurality of cells 10 are arranged such that the side surfaces of the cells 10 having the largest area face each other. A cooling plate, a buffer plate, or the like (not shown) is arranged in the gap between the two unit cells 10 adjacent to each other.

The cell 10 has a terminal (electrode terminal) 3 for positive electrode and a terminal (electrode terminal) 4 for negative electrode. The plurality of single cells 10 are reversed one by one so that the respective terminals 3 and terminals 4 are alternately arranged. A plurality of unit cells 10 are arranged such that a terminal 3 of one of two adjacent unit cells 10 and a terminal 4 of the other unit cell 10 are adjacent to each other.

The cell 10 is, for example, a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. A cell has, for example, a rectangular shape. In addition, the single cell is not limited to a square shape, and may be a cylindrical shape. The secondary battery may use a liquid electrolyte or may use a solid electrolyte.

The assembled battery 1 includes bus bars 2 that connect adjacent unit cells 10 to each other. The bus bar 2 includes a terminal 3 (first terminal) of one of the two adjacent cells 10 and a terminal 4 (first terminal) of the other of the two adjacent cells 10. second terminal). Bus bar 2 electrically connects terminal 3 of one cell 10 and terminal 4 of the other cell 10 . Thus, a plurality of single cells 10 are connected in series to construct an assembled battery 1 having a desired voltage.

2 is an enlarged plan view showing the periphery of the bus bar shown in FIG. 1. FIG. FIG. 3 is a cross-sectional view taken along line III-III shown in FIG. A bus bar 2 according to the embodiment will be described with reference to FIGS. 2 and 3. FIG.

As shown in FIGS. 2 and 3, busbar 2 has a plate-like shape. The busbar 2 has a first end 2a and a second end 2b facing each other. The first end portion 2a and the second end portion 2b are both ends of the bus bar 2 in the width direction W orthogonal to the length direction L parallel to the arrangement direction of the cells 10 (arrow AR1 direction in FIG. 1). .

The bus bar 2 is joined to the terminals 3 and 4 on the side of the first end portion 2a. The bus bar 2 is not joined to the terminals 3 and 4 on the side of the second end portion 2b. The bus bar 2 is located at a position where most of the bus bar 2 does not overlap the terminals 3 and 4 in the width direction W. As shown in FIG.

The first end portion 2a includes a first joint portion 2a1 joined to the terminal 3 by welding or the like, a second joint portion 2a2 joined to the terminal 4 by welding or the like, and the first joint portion 2a1 and the second joint portion 2a1. It includes a connection portion 2a3 that connects the portions 2a2.

The first joint portion 2a1 and the second joint portion 2a2 extend in a direction parallel to the length direction L, for example. The connection portion 2a3 has a curved portion that is recessed toward the second end portion 2b when viewed from above in a vertical direction (DR1 direction in FIG. 3) orthogonal to the length direction L and the width direction W.

The second end portion 2b is provided so as to curve away from the first end portion 2a when viewed from above in a vertical direction perpendicular to the length direction L and the width direction W. As shown in FIG.

FIG. 4 is an enlarged plan view showing the periphery of a busbar provided in an assembled battery in a comparative example. The assembled battery 1X in the comparative example will be described with reference to FIG.

As shown in FIG. 4, the assembled battery 1X in the comparative example differs from the assembled battery 1 according to the first embodiment in the shape of the bus bar 2X. Other configurations are substantially the same.

The busbar 2X has a rectangular shape when viewed in the vertical direction. The first end portion 2a and the second end portion 2b of the busbar 2 are parallel to the length direction L and provided linearly. The bus bar 2 is joined to the terminals 3 and 4 on the side of the first end 2a, and is not joined to the terminals 3 and 4 on the side of the second end 2b.

In FIG. 4, when the single cell 10 expands, the distance between the single cells 10 increases mainly in the arrow AR2 direction.

FIG. 5 is a diagram showing the distribution of stress applied to the busbars when the distance between adjacent cells increases in the assembled battery of the comparative example.

As shown in FIG. 5, in the stress distribution applied to bus bar 2X, the stress concentrates on the first end portion 2a side, and a high-stress region R1 is formed on the first end portion 2a side. A slightly high stress region R2 is formed adjacent to the region R1. On the side of the second end portion 2b, a region R3 where the stress is small is formed in the majority of half or more in the width direction. That is, it is difficult to disperse the applied stress in the width direction W in the bus bar 2X of the comparative example.

When the stress is applied with the distribution as described above, the first end 2a side of the bus bar 2X is largely plastically deformed so as to widen along the length direction L. As shown in FIG.

FIG. 6 is a diagram showing the distribution of stress applied to the busbar when the distance between adjacent cells increases in the assembled battery according to the first embodiment.

In the first embodiment, as shown in FIG. 6, in the distribution of stress applied to bus bar 2, the stress is slightly greater at first joint portion 2a1 and second joint portion 2a2, and the stress is slightly greater at first joint portion 2a1 and second joint portion 2a2, and the second The stress decreases toward the end portion 2b side, that is, toward the region R10 from the region R5.

As described above, in the busbar 2 according to the first embodiment, the first end portion 2a has a curved portion 2a3 that is recessed toward the second end portion when viewed from above, thereby providing a long The force applied along the length direction L is also distributed in the width direction W. Accordingly, even when the first end portion 2a side is connected to the terminals 3 and 4, it is possible to suppress concentration of stress on the first end portion 2a side.

(Embodiment 2)
FIG. 7 is an enlarged plan view showing the periphery of a busbar provided in the assembled battery according to the second embodiment. An assembled battery 1A according to Embodiment 2 will be described with reference to FIG.

As shown in FIG. 7, the assembled battery 1A according to the second embodiment differs from the assembled battery 1A according to the first embodiment in that the busbar 2 is provided with an opening 21 . Other configurations are substantially the same.

The opening 21 is provided so as to pass through the busbar 2 in the thickness direction. The opening 21 is provided substantially in the center in the length direction L. As shown in FIG. The opening 21 is provided so that the width of the opening decreases from the second end 2b toward the first end 2a. A single opening 21 may be provided, or a plurality of openings 21 may be provided.

Even with such a configuration, the assembled battery 1A according to the second embodiment can obtain substantially the same effects as those of the first embodiment.

In addition, the rigidity of bus bar 2 can be reduced by providing opening 21 as described above. This makes it easier for the busbars 2 to deform so as to follow the displacement of the distance between the adjacent unit cells.

(Embodiment 3)
FIG. 8 is an enlarged plan view showing the periphery of a busbar provided in the assembled battery according to the third embodiment. An assembled battery 1B according to Embodiment 3 will be described with reference to FIG.

As shown in FIG. 8, the assembled battery 1B according to the third embodiment differs from the assembled battery 1 according to the first embodiment in the shape of the bus bar 2B. Other configurations are substantially the same.

Bus bar 2B is provided in a straight line so that second end 2b is parallel to length direction L, as compared with bus bar 2 according to the first embodiment.

Even with such a configuration, the assembled battery 1B according to the third embodiment can obtain substantially the same effects as those of the first embodiment.

(Embodiment 4)
FIG. 9 is an enlarged plan view showing the periphery of a busbar provided in the assembled battery according to the fourth embodiment. An assembled battery 1C according to Embodiment 4 will be described with reference to FIG.

As shown in FIG. 9, the assembled battery 1C according to the fourth embodiment differs from the assembled battery 1 according to the first embodiment in the shape of the bus bar 2C. Other configurations are substantially the same.

Busbar 2C is provided in a straight line so that second end 2b is parallel to length direction L, unlike busbar 2 according to the first embodiment. Two openings 21 are provided in the busbar 2C. The two openings 21 are provided on both end sides in the length direction L on the second end 2b side. The number of openings 21 is not limited to two, and may be one or three or more. In addition, the position of the openings 21 can be appropriately changed according to the number.

Even with such a configuration, the assembled battery 1C according to the fourth embodiment can obtain substantially the same effects as the assembled battery 1 according to the first embodiment. In addition, the rigidity of bus bar 2 can be reduced by providing opening 21 as described above. This makes it easier for the busbars 2 to deform so as to follow the displacement of the distance between the adjacent unit cells.

(Embodiment 5)
10 is a cross-sectional view of an assembled battery according to Embodiment 5. FIG. 10 is a cross-sectional view of a portion corresponding to FIG. An assembled battery 1D according to Embodiment 5 will be described with reference to FIG.

As shown in FIG. 10, the assembled battery 1D according to the fifth embodiment differs from the assembled battery 1 according to the first embodiment in the shape of the bus bar 2D. Other configurations are substantially the same.

The outer shape of busbar 2D is substantially the same as the outer shape of busbar 2 according to the first embodiment. The busbar 2D is provided so that the central portion in the length direction L is recessed downward.

Even with such a configuration, the assembled battery 1D according to the fifth embodiment can obtain substantially the same effects as the assembled battery 1 according to the first embodiment.

(Embodiment 6)
11 is a cross-sectional view of an assembled battery according to Embodiment 6. FIG. An assembled battery 1E according to Embodiment 6 will be described with reference to FIG.

As shown in FIG. 11, in the assembled battery 1E according to the sixth embodiment, when compared with the assembled battery 1 according to the first embodiment, the outer shape of the busbar 2E is different from the outer shape of the busbar 2 according to the first embodiment. Almost the same. The bus bar 2E is positioned lower on the side of the second end 2b than on the side of the first end 2a. That is, the bus bar 2E is provided with an inclined portion 2c that is inclined so as to approach the cell 10 toward the second end portion 2b side.

Even with such a configuration, the assembled battery 1E according to the sixth embodiment can obtain substantially the same effect as the assembled battery 1 according to the first embodiment.

In the above-described embodiment, the case where the unit cells 10 are electrically connected in series by the busbar has been described as an example, but the present invention is not limited to this. may be connected.

As described above, the embodiments disclosed this time are illustrative in all respects and are not restrictive. The scope of the present invention is indicated by the scope of claims, and includes all modifications within the meaning and scope of equivalence to the scope of claims.

1, 1A, 1B, 1C, 1D, 1E, 1X assembled battery, 2, 2B, 2C, 2D, 2E, 2X busbar, 2a first end, 2a1 first joint, 2a2 second joint, 2a3 connection , 2b second end, 2c inclined portion, 3, 4 terminal, 10 cell, 21 opening.

Claims (1)

a plurality of single cells arranged side by side in the arrangement direction;
a bus bar electrically connecting a first electrode terminal of one of the adjacent cells and a second electrode terminal of the other of the adjacent cells; prepared,
The busbar includes a first end and a second end that are both ends of the busbar in a width direction orthogonal to a length direction parallel to the arrangement direction,
The first end includes a first joint portion joined to the first electrode terminal, a second joint portion joined to the second electrode terminal, the first joint portion and the second joint portion. and a connecting portion for connecting the
The connecting portion has a curved portion that is recessed toward the second end portion when viewed in plan from a direction orthogonal to the length direction and the width direction,
The bus bar is arranged such that a thickness direction orthogonal to the length direction and the width direction is parallel to the height direction, and the thickness in the thickness direction is equal to the length in the length direction and the width direction. Having a plate-like shape shorter than the width in the width direction,
The second end is located at the same height position as the first end or at a position lower than the first end in the height direction ,
A portion of the bus bar located on the second end side is connected to both the first electrode terminal and the second electrode terminal in the height direction from one end to the other end of the bus bar in the length direction. including parts that do not overlap with
The assembled battery , wherein the second end is not joined to the first electrode terminal and the second electrode terminal .

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