JP7775138B2 - Battery module - Google Patents

Description

The present invention relates to a battery module.

In recent years, various battery modules have been developed that include multiple battery cells. Each battery cell includes a battery element, an exterior material that seals the battery element, and a positive electrode tab and a negative electrode tab that extend from the exterior material.

Patent Document 1 describes an example of a battery module. In this battery module, positive and negative electrode tabs extend from opposite sides of an exterior material. In this battery module, the positive electrode tabs of a single battery cell or multiple battery cells connected in parallel are joined to the negative electrode tabs of a single battery cell or multiple battery cells connected in parallel. The positive and negative electrode tabs are folded back between the battery cell with the positive electrode tab and the battery cell with the negative electrode tab.

Patent Document 2 describes an example of a battery module. In this battery module, multiple tips of multiple positive electrode tabs or multiple negative electrode tabs of multiple battery cells are bent in a direction.

Patent Document 3 describes an example of a battery module. In this battery module, the tips of the positive and negative electrode tabs are bent.

WO 2006/109610 International Publication No. 2016/020999 International Publication No. 2011/027817

For example, as described in Patent Document 1, the positive and negative electrode tabs may be folded back between at least one battery cell and at least one other battery cell. However, in this case, the workability of connecting at least one battery cell in series with at least one other battery cell may be reduced.

One object of the present invention is to improve the ease of connecting at least one battery cell in series with at least one other battery cell. Other objects of the present invention will become apparent from the description of this specification.

One aspect of the present invention is as follows.
[1]
at least one positive electrode tab having a predetermined first tip portion bent in a predetermined direction around a predetermined first bend portion;
at least one negative electrode tab joined to the at least one positive electrode tab, the negative electrode tab having a predetermined second tip portion bent toward the predetermined direction around a predetermined second bend portion;
Equipped with
the first bent portion and the second bent portion are shifted to the opposite side of the predetermined direction with respect to a virtual bisector of a virtual line segment connecting a predetermined first base end of the at least one positive electrode tab and a predetermined second base end of the at least one negative electrode tab.
[2]
The battery module according to [1], further comprising a voltage detection unit joined to at least one of the first end portion and the second end portion.
[3]
a plurality of tab groups each including at least one positive electrode tab and at least one negative electrode tab joined together;
The battery module has a tip end portion of each of the plurality of tab groups bent in the same direction.
[4]
The battery module according to [3], further comprising a plurality of voltage detection units joined to the tip ends of the plurality of tab groups.
[5]
at least one positive electrode tab having a predetermined first tip bent in a predetermined direction;
at least one negative electrode tab joined to the at least one positive electrode tab, with a predetermined second tip bent toward the predetermined direction;
a voltage detection unit joined to at least one of the first tip portion and the second tip portion;
A battery module comprising:

The above-described aspects of the present invention can improve the ease of connecting at least one battery cell in series with at least one other battery cell.

FIG. 2 is a perspective view of a front portion of the battery module according to the embodiment. 2 is a cross-sectional view taken along the line AA' in FIG. FIG. 1 is a top view of a front portion of a first battery cell and a front portion of a second battery cell among a plurality of battery cells according to an embodiment; 5A to 5C are diagrams for explaining a first example of a method for manufacturing a battery module according to an embodiment. 5A to 5C are diagrams for explaining a first example of a manufacturing method for a battery module according to an embodiment. 5A to 5C are diagrams for explaining a first example of a method for manufacturing a battery module according to an embodiment. 10A to 10C are diagrams illustrating a manufacturing method of a battery module according to a comparative example. 10A to 10C are diagrams illustrating a method for manufacturing a battery module according to a comparative example. 10A to 10C are diagrams for explaining a second example of the manufacturing method of the battery module according to the embodiment. 10A to 10C are diagrams for explaining a second example of the manufacturing method of the battery module according to the embodiment. FIG. 10 is a top view of the front portion of the battery module according to Modification 1. FIG. 11 is a top view of the front portion of a battery module according to Modification 2.

Embodiments of the present invention will be described below using the drawings. In all drawings, similar components will be designated by similar reference numerals, and descriptions will be omitted where appropriate.

Figure 1 is a perspective view of the front portion of a battery module 10 according to an embodiment. Figure 2 is a cross-sectional view taken along line A-A' in Figure 1.

For the purpose of explanation, arrows indicating the X, Y, and Z directions are shown in each figure. The X direction indicates the front-to-rear direction of the battery module 10. Unless otherwise specified, the tip of an arrow indicating the X direction will be referred to as the rear side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the X direction will be referred to as the front side of the battery module 10. The Y direction is perpendicular to the X direction. The Y direction indicates the left-to-right direction of the battery module 10. Unless otherwise specified, the tip of an arrow indicating the Y direction will be referred to as the left side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the Y direction will be referred to as the right side of the battery module 10. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the up-down direction of the battery module 10. Unless otherwise specified, the tip of an arrow indicating the Z direction will be referred to as the upper side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the Z direction will be referred to as the lower side of the battery module 10. In Figure 2, the white circle with a black dot indicating the Z direction indicates the upper side of the battery module 10 from the back to the front of the page, and the lower side of the battery module 10 from the front to the back of the page. However, the relationship between the X direction, Y direction, and Z direction and the front-to-back, left-to-right, and up-to-down directions of the battery module 10 is not limited to the example described above. These relationships will vary depending on the actual arrangement of the battery module 10.

The battery module 10 will be described with reference to Figure 1, and, if necessary, Figure 2.

The battery module 10 includes multiple battery cells 100 and a voltage detection unit 200.

In the example shown in Figure 1, four battery cells 100 are illustrated as an example. However, the number of battery cells 100 included in the battery module 10 is not limited to the example shown in Figure 1. The multiple battery cells 100 are stacked in the Y direction. In the example shown in Figure 1, the longitudinal direction of each battery cell 100 is approximately parallel to the X direction. The lateral direction of each battery cell 100 is approximately parallel to the Z direction. The thickness direction of each battery cell 100 is approximately parallel to the Y direction. However, the shape of each battery cell 100 is not limited to the example shown in Figure 1.

As shown in Figures 1 and 2, each battery cell 100 has a battery element 110, an exterior material 120, a positive electrode tab 132, and a negative electrode tab 134.

As shown in FIG. 2, the battery element 110 includes a plurality of positive electrodes 112 and a plurality of negative electrodes 114. The plurality of positive electrodes 112 and a plurality of negative electrodes 114 are stacked alternately in the Y direction. Adjacent positive electrodes 112 and negative electrodes 114 in the Y direction are separated from each other by separators (not shown). However, the structure of the battery element 110 is not limited to this example.

As shown in Figure 2, the exterior material 120 seals the battery element 110 and the electrolyte (not shown).

The positive electrode tab 132 is electrically connected to multiple positive electrodes 112. The electrical connection between the positive electrode tab 132 and multiple positive electrodes 112 will be described with reference to the example shown in FIG. 2. In the example shown in FIG. 2, the positive electrode tab 132 is located in front of the battery element 110. The base end A on the rear end side of the positive electrode tab 132 is located within the area sealed by the exterior material 120. In the example shown in FIG. 2, the positive electrode tab 132 extends diagonally forward and to the right from the base end A when viewed from above. The positive electrode tab 132 is joined to multiple positive electrode current collector foils 112a. In the example shown in FIG. 2, the multiple positive electrode current collector foils 112a are pulled out from the multiple positive electrodes 112 toward the front of the battery element 110 and are bundled together near the base end A of the positive electrode tab 132. This electrically connects the positive electrode tab 132 to the multiple positive electrodes 112. Similar to the example shown in FIG. 2, the negative electrode tab 134 is electrically connected to multiple negative electrodes 114 via multiple negative electrode current collector foils (not shown) that are pulled out from the multiple negative electrodes 114.

In each battery cell 100, the positive electrode tab 132 and the negative electrode tab 134 extend from opposite sides of the exterior material 120 in the X direction. The positive electrode tab 132 is made of, for example, aluminum. The negative electrode tab 134 is made of, for example, copper. In battery cells 100 adjacent to each other in the Y direction, the positive electrode tabs 132 and the negative electrode tabs 134 of each battery cell 100 are staggered in the X direction. As a result, for example, in the example shown in FIG. 1, the leftmost battery cell 100 has a positive electrode tab 132 located in front of the battery cell 100 and a negative electrode tab 134 (not shown) located behind the battery cell 100. In the example shown in FIG. 1, the second battery cell 100 from the left has a negative electrode tab 134 located in front of the battery cell 100 and a positive electrode tab 132 (not shown) located behind the battery cell 100.

Adjacent battery cells 100 in the Y direction have tab groups 130 located in front of or behind the adjacent battery cells 100. Each tab group 130 includes a positive electrode tab 132 and a negative electrode tab 134 joined to each other. Each tab group 130 includes a tip group BG. The tip group BG includes the tip of the positive electrode tab 132 and the tip of the negative electrode tab 134. In the example shown in FIG. 1, all of the multiple tip groups BG located in the front of the battery module 10 are bent in the same direction when viewed from above. This makes the tip group BG approximately parallel to the Y direction. This makes it easy to join the voltage detection unit 200 to the front surface of the tip group BG with the thickness direction of the voltage detection unit 200 approximately parallel to the X direction. The tip group BG has a first joint 150. The positive electrode tabs 132 and negative electrode tabs 134 included in each tab group 130 are joined to each other at the first joint 150. The first joint 150 is formed, for example, by laser welding. However, the method for forming the first joint 150 is not limited to this example.

The plurality of tab groups 130 located in front of the plurality of battery cells 100 and the plurality of tab groups 130 (not shown) located behind the plurality of battery cells 100 are arranged alternately in the Y direction. As a result, adjacent battery cells 100 in the Y direction are connected in series. For example, in the example shown in FIG. 1, the two left-hand battery cells 100 are connected in series via the tab groups 130 located in front of these battery cells 100. In the example shown in FIG. 1, the two center battery cells 100 are connected in series via the tab groups 130 (not shown) located behind these battery cells 100.

Each of the multiple voltage detection units 200 is joined to each of the multiple tip group BGs. Each voltage detection unit 200 is made of a conductor such as metal. In the example shown in FIG. 2, the voltage detection unit 200 is joined to the front surface of the tip group BG located in front of the battery module 10. Each voltage detection unit 200 and each tip group BG are joined to each other at a second joint 250. The second joint 250 is formed, for example, by laser welding. However, the method of forming the second joint 250 is not limited to this example.

Each of the multiple voltage detection units 200 is electrically connected to a respective one of multiple voltage detection lines (not shown). Therefore, it is possible to detect the voltage of each tab group 130 using each voltage detection unit 200 and each voltage detection line.

Figure 3 is a top view of the front portions of the first battery cell 100A and the second battery cell 100B among the plurality of battery cells 100 according to the embodiment.

The first battery cell 100A and the second battery cell 100B are adjacent to each other in the Y direction. When viewed from above, the first battery cell 100A is located to the left of the second battery cell 100B. When viewed from above, the second battery cell 100B is located to the right of the first battery cell 100A.

The first battery cell 100A has a first positive electrode tab 132A. The first positive electrode tab 132A includes a first base end A1, a first tip end B1, and a first bent portion C1. The second battery cell 100B has a second negative electrode tab 134B. The second negative electrode tab 134B includes a second base end A2, a second tip end B2, and a second bent portion C2. The first positive electrode tab 132A and the second negative electrode tab 134B constitute a tab group 130. The first tip end B1 and the second tip end B2 constitute a tip end group BG.

Figure 3 shows the imaginary line segment LS and the imaginary bisector BS. When viewed from above, the imaginary line segment LS connects the first base end A1 and the second base end A2. When viewed from above, the imaginary line segment LS is approximately parallel to the Y direction. When viewed from above, the imaginary bisector BS is the perpendicular bisector of the imaginary line segment LS. When viewed from above, the imaginary bisector BS is approximately parallel to the X direction.

When viewed from above, the first tip B1 is bent leftward around the first bend C1. When viewed from above, the second tip B2 is bent leftward around the second bend C2. When viewed from above, the first bend C1 and the second bend C2 are shifted to the right with respect to the imaginary bisector BS. In other words, the first bend C1 and the second bend C2 are shifted to the opposite side of the imaginary bisector BS from the direction in which the first tip B1 and the second tip B2 are bent.

When viewed from above, the portion between the first base end A1 and the first bend C1 of the first positive electrode tab 132A is inclined at a first angle θ1 with respect to the X direction. When viewed from above, the portion between the second tip end B2 and the second bend C2 of the second negative electrode tab 134B is inclined at a second angle θ2 with respect to the X direction. As described above, when viewed from above, the first bend C1 and the second bend C2 are shifted to the right with respect to the imaginary bisector BS. As a result, the second angle θ2 is smaller than the first angle θ1.

In this embodiment, it is possible to suppress fluctuations in the positions of the first base end A1 and the second base end A2 and fluctuations in the first angle θ1 and the second angle θ2 due to bending of the first positive electrode tab 132A and the second negative electrode tab 134B. This suppresses phenomena such as breakage of the current collecting foil due to fluctuations in the positions of the first base end A1 and the second base end A2 and fluctuations in the first angle θ1 and the second angle θ2. Specifically, when viewed from above, the radius of curvature of the first bent portion C1 of the first positive electrode tab 132A is smaller than the radius of curvature of the second bent portion C2 of the second negative electrode tab 134B. In this embodiment, by shifting the first bent portion C1 toward the second bent portion C2 when viewed from above, it is possible to align the length of the first bent portion C1 and its periphery of the first positive electrode tab 132A with the length of the second bent portion C2 and its periphery of the second negative electrode tab 134B. Therefore, in this embodiment, when viewed from above, the first base end A1 can be prevented from moving rearward by the first bent portion C1 of the first positive electrode tab 132A and the excess length around it. Also, in this embodiment, when viewed from above, the second base end A2 can be prevented from moving forward by the second bent portion C2 of the second negative electrode tab 134B and the insufficient length around it.

In the example shown in FIG. 3, the tip group BG is bent toward the left when viewed from above. However, the tip group BG may also be bent toward the right when viewed from above. In this case, the first bent portion C1 and the second bent portion C2 can be shifted toward the left with respect to the imaginary bisector BS.

Figures 4 to 6 are diagrams illustrating a first example of a method for manufacturing a battery module 10 according to an embodiment. In this first example, the battery module 10 according to an embodiment is manufactured as follows.

First, the first battery cell 100A and the second battery cell 100B are arranged next to each other in the Y direction with the first positive electrode tab 132A and the second negative electrode tab 134B pulled out forward.

The first tip portion B1 and the second tip portion B2 are then joined together to form the first joint portion 150. The first tip portion B1 and the second tip portion B2 are joined by, for example, laser welding. However, the method for joining the first tip portion B1 and the second tip portion B2 is not limited to this example. In the laser welding of the embodiment, the laser can be applied from either the left or right side of the first tip portion B1 and the second tip portion B2. This improves the workability of joining the first tip portion B1 and the second tip portion B2.

Note that the order of the steps for joining the first tip portion B1 and the second negative electrode tab 134B is not limited to the example described above. For example, the first tip portion B1 and the second tip portion B2 may be joined after being bent as described below.

Next, as shown in Figure 4, the first tip B1 and the second tip B2 are clamped by a pair of bending fingers 300A.

Next, as shown in FIG. 5, the pair of bending fingers 300A are rotated clockwise when viewed from above. This causes the first tip portion B1 and the second tip portion B2 to bend toward the left when viewed from above. In the example shown in FIG. 5, the first positive electrode tab 132A and the second negative electrode tab 134B are bent so that the first bent portion C1 and the second bent portion C2 are shifted to the right with respect to the imaginary bisector BS when viewed from above. Therefore, as described above, it is possible to suppress fluctuations in the positions of the first base end A1 and the second base end A2 due to bending of the first positive electrode tab 132A and the second negative electrode tab 134B.

Next, a pair of bending fingers 300A are removed from the tab group 130. In this case, the bending finger 300A located behind the tip group BG can be moved toward the front of the tab group 130 through the space to the left of the tip group BG when viewed from above. In this embodiment, multiple tip groups BG located at the front of the battery module 10 are bent in the same direction. For example, in the example shown in FIG. 1, both tip groups BG of tab groups 130 adjacent in the Y direction are bent toward the left when viewed from above. In this example, the Y-direction width of the space between adjacent tip groups BG can be increased compared to when the left tip group BG shown in FIG. 1 is bent toward the right when viewed from above and the right tip group BG shown in FIG. 1 is bent toward the left when viewed from above. Therefore, in this embodiment, the bending finger 300A located behind the right-hand tip group BG shown in FIG. 1 can be easily removed toward the front of the tab group 130 through the space between the tip group BG adjacent in the Y direction. Therefore, in this embodiment, the workability for removing a pair of bending fingers 300A from the tab group 130 can be improved.

Next, as shown in FIG. 6, with the voltage detection unit 200 positioned in front of the tip group BG, the tip group BG and voltage detection unit 200 are sandwiched between the first laser finger 410A and the second laser finger 420A. The first laser finger 410A is positioned in front of the voltage detection unit 200. The second laser finger 420A is positioned behind the tip group BG. Next, a laser is irradiated toward the front surface of the voltage detection unit 200 through the laser hole 412A provided in the first laser finger 410A. This forms the second bonding portion 250, bonding the voltage detection unit 200 to the tip group BG.

In the example shown in Figure 6, when viewed from above, a space is provided to the left of the tip group BG for passing the second laser finger 420A behind the tip group BG. This allows the second laser finger 420A to be positioned behind the tip group BG without having to move the second laser finger 420A upward or downward. This improves the ease of positioning the second laser finger 420A behind the tip group BG.

Note that the order of the process of joining the voltage detection unit 200 to the tip group BG is not limited to the example described above. For example, the voltage detection unit 200 may be joined to the tip group BG before the tip group BG is bent.

Figures 7 and 8 are diagrams illustrating a method for manufacturing a battery module according to a comparative embodiment. The method for manufacturing the battery module according to the comparative embodiment is the same as the method for manufacturing the battery module 10 according to the embodiment, except for the following points.

First, the first battery cell 100A and the second battery cell 100B are aligned in the X direction with the first tip portion B1 and the second tip portion B2 overlapping in the Y direction.

Next, as shown in FIG. 7, the first tip B1 and second tip B2 are sandwiched between a pair of first bending fingers 310K. The portion of the first positive electrode tab 132A between the first base end A1 and the first tip B1 is sandwiched between a pair of second bending fingers 320K. The portion of the second negative electrode tab 134B between the second base end A2 and the second tip B2 is sandwiched between a pair of third bending fingers 330K.

Next, with the position of the pair of third bending fingers 330K fixed, the pair of first bending fingers 310K and the pair of third bending fingers 330K are rotated clockwise when viewed from above. This causes the portion of the second negative electrode tab 134B between the pair of first bending fingers 310K and the pair of third bending fingers 330K to be bent at approximately a right angle when viewed from above.

Next, as shown in FIG. 8 , while the positions of the pair of first bending fingers 310K and the pair of third bending fingers 330K are fixed, the pair of second bending fingers 320K are rotated clockwise when viewed from above. This causes the portion of the first positive electrode tab 132A between the pair of first bending fingers 310K and the pair of second bending fingers 320K to be folded at a substantially right angle when viewed from above. As a result, the first positive electrode tab 132A and the second negative electrode tab 134B form a folded tab group 130K. The folded tab group 130K is folded between the first base end A1 and the second base end A2.

Next, the voltage detection unit 200 is joined to the front surface of the first tip portion B1.

Compare the embodiment shown in Figures 4 to 6 with the comparative embodiment shown in Figures 7 and 8.

In the comparative embodiment, the shorter the Y-direction distance between the first base end A1 and the second base end A2 of the folded tab group 130K, the thinner the width of the first bending finger 310K, the second bending finger 320K, and the third bending finger 330K located on the inside of the folded tab group 130K in the direction perpendicular to the Z-direction must be. The narrower the width of each finger, the greater the degree to which each finger is likely to bend in the Z-direction. Therefore, in the comparative embodiment, the shorter the Y-direction distance between the first base end A1 and the second base end A2 of the folded tab group 130K, the more difficult it may be to form the folded tab group 130K. In contrast, in the embodiment, the first tip B1 and the second tip B2 can be bent regardless of the Y-direction distance between the first base end A1 and the second base end A2. Therefore, in the embodiment, the workability of bending the tip group BG can be improved compared to the comparative embodiment.

In the comparative embodiment, the first folded finger 310K, the second folded finger 320K, and the third folded finger 330K located inside the folded tab group 130K must be moved upward or downward to remove these fingers. In contrast, in the embodiment, the folded finger 300A located behind the tip group BG can be removed through the space between adjacent tip groups BG in the Y direction. Therefore, in the embodiment, the folded finger 300A located behind the tip group BG can be removed without moving the folded finger 300A upward or downward. Therefore, in the embodiment, the workability for removing the folded finger 300A located behind the tip group BG can be improved compared to the comparative embodiment.

Figures 9 and 10 are diagrams illustrating a second example of a method for manufacturing a battery module 10 according to an embodiment. The second example shown in Figures 9 and 10 is similar to the first example shown in Figures 4 to 6, except for the following points.

As shown in FIG. 9 , the portion between the first tip B1 and first base A1 of the first positive electrode tab 132A and the portion between the second tip B2 and second base A2 of the second negative electrode tab 134B are sandwiched between the first fixed bending finger 312B and the second fixed bending finger 314B. When viewed from above, the first fixed bending finger 312B is positioned on the left side of the first positive electrode tab 132A. When viewed from above, the second fixed bending finger 314B is positioned on the right side of the second negative electrode tab 134B. Next, when viewed from above, the movable bending finger 320B is positioned in front of the second fixed bending finger 314B and to the right of the second tip B2.

Next, as shown in Figure 10, the movable bending finger 320B is rotated clockwise when viewed from above. This causes the tip group BG to bend toward the left when viewed from above.

Figure 11 is a top view of the front portion of the battery module 10A according to Modification 1. The battery module 10A according to Modification 1 is similar to the battery module 10 according to the embodiment, except for the following points.

In Modification 1, when viewed from above, the tip group BG is bent toward the left. The first bent portion C1 and the second bent portion C2 are shifted to the right with respect to the imaginary bisector BS. The portion between the first base end A1 and the first bent portion C1 of the first positive electrode tab 132A is inclined at an angle θ with respect to the X direction. In contrast, the portion between the second base end A2 and the second bent portion C2 of the second negative electrode tab 134B is approximately parallel to the X direction. Even in Modification 1, fluctuations in the positions of the first base end A1 and the second base end A2 due to bending of the first positive electrode tab 132A and the second negative electrode tab 134B can be suppressed.

Figure 12 is a top view of the front portion of the battery module 10B according to Modification 2. The battery module 10B according to Modification 2 is similar to the battery module 10 according to the embodiment, except for the following points.

The battery module 10B according to Modification 2 includes four battery cells 100 as shown in FIG. 12. In the example shown in FIG. 12, the two battery cells 100 on the left side are connected in parallel. In the example shown in FIG. 12, the two battery cells 100 on the right side are connected in parallel. The two battery cells 100 connected in parallel on the left side shown in FIG. 12 and the two battery cells 100 connected in parallel on the right side shown in FIG. 12 are connected in series.

Two positive electrode tabs 132 extend forward from the two battery cells 100 connected in parallel on the left side shown in FIG. 12 . Two negative electrode tabs 134 extend forward from the two battery cells 100 connected in parallel on the right side shown in FIG. 12 . These tabs are joined to each other. Specifically, a tip group BG including the tips of these tabs is bent toward the left when viewed from above. In the tip group BG, the tips of the above-mentioned tabs are joined to each other. In the example shown in FIG. 12 , the voltage detection unit 200 is joined to the front surface of the tip group BG. In the second variant, as in the embodiment, the workability of connecting in series the two battery cells 100 connected in parallel on the left side shown in FIG. 12 and the two battery cells 100 connected in parallel on the right side shown in FIG. 12 can be improved.

In the example shown in Figure 12, a battery cell group including two battery cells 100 connected in parallel is connected in series. However, even when a battery cell group including three or more battery cells 100 connected in parallel is connected in series, a structure similar to the structure described using Figure 12 can be adopted.

The above describes embodiments of the present invention with reference to the drawings, but these are merely examples of the present invention, and various configurations other than those described above can also be adopted.

10, 10A, 10B Battery module 100 Battery cell 100A First battery cell 100B Second battery cell 110 Battery element 112 Positive electrode 112a Positive electrode current collector foil 114 Negative electrode 120 Exterior material 130 Tab group 130K Folded tab group 132 Positive electrode tab 132A First positive electrode tab 134 Negative electrode tab 134B Second negative electrode tab 150 First joint 200 Voltage detection section 250 Second joint 300A Bending finger 310K First bending finger 312B First fixed bending finger 314B Second fixed bending finger 320B Movable bending finger 320K Second bending finger 330K Third bending finger 410A First laser finger 412A Laser hole 420A Second laser finger A Base end A1 First base end A2 Second base end B1 First distal end B2 Second distal end BG Distal end group BS Virtual bisector C1 First bent portion C2 Second bent portion LS Virtual line segment

Claims (5)

at least one positive electrode tab having a first base end, a first tip end, and a first bent portion, the first base end extending from a first base end located closest to the base end of the at least one positive electrode tab to the first bent portion, and the first tip end being bent in a predetermined direction around the first bent portion;
at least one negative electrode tab having a second base end, a second tip end, and a second bent portion, wherein the second base end extends from a second base end located closest to the base end of the at least one negative electrode tab to the second bent portion, the first tip end and the second tip end are joined to each other by laser welding , and the second tip end is bent in the predetermined direction around the second bent portion;
Equipped with
the first base end of the at least one positive electrode tab is inclined with respect to a first imaginary line that passes through the first base end in a direction perpendicular to an imaginary line segment connecting the first base end and the second base end, and the second base end of the at least one negative electrode tab is inclined with respect to a second imaginary line that passes through the second base end in a direction perpendicular to the imaginary line segment,
the first bent portion and the second bent portion are offset to the opposite side of the predetermined direction with respect to a virtual bisector of the virtual line segment. The battery module of claim 1, further comprising a voltage detection unit joined to at least one of the first end portion and the second end portion. a plurality of tab groups each including at least one positive electrode tab and at least one negative electrode tab joined together;
the at least one positive electrode tab has a first base end, a first tip end, and a first bent portion, the first base end extending from a first base end located closest to the base end of the at least one positive electrode tab to the first bent portion, and the first tip end being bent around the first bent portion;
the at least one negative electrode tab has a second base end, a second tip end, and a second bent portion, the second base end extends from a second base end located closest to the base end of the at least one negative electrode tab to the second bent portion, the first tip end and the second tip end are joined to each other by laser welding , and the second tip end is bent around the second bent portion,
the first base end of the at least one positive electrode tab is inclined with respect to a first imaginary line that passes through the first base end in a direction perpendicular to an imaginary line segment connecting the first base end and the second base end, and the second base end of the at least one negative electrode tab is inclined with respect to a second imaginary line that passes through the second base end in a direction perpendicular to the imaginary line segment,
a group of leading ends including the first leading end and the second leading end of each of the plurality of tab groups is bent in the same direction. The battery module of claim 3 further comprises a plurality of voltage detection units joined to at least one of the first end portions and the second end portions of the plurality of tab groups. at least one first battery cell including a first battery element, a first exterior material sealing the first battery element, and a positive electrode tab drawn out from the first exterior material, the positive electrode tab having a first tip portion bent in a predetermined direction;
at least one second battery cell including a second battery element, a second exterior material sealing the second battery element, and a negative electrode tab pulled out from the second exterior material, wherein the negative electrode tab has a second tip portion bent in the predetermined direction, and the first tip portion and the second tip portion are joined to each other by laser welding ;
a voltage detection portion laser-welded to at least one of the first tip portion and the second tip portion;
Equipped with
The voltage detection unit is located on the side of the first end portion and the second end portion opposite to the side where the first battery element and the second battery element are located.