Battery module

Abstract

To improve the operability for serially connecting at least one first cell and at least one second cell to each other.SOLUTION: A battery module 10 includes a first positive electrode tab 132A and a second negative electrode tab 134B. A first end part B1 of the first positive electrode tab 132A is bent to a predetermined direction on the basis of a first bending part C1. The second positive electrode tab 134B is joined to the first positive electrode tab 132A. A second end part B2 of the second negative electrode tag 134B is bent to a predetermined direction on the basis of a second bending part C2. The first end part B1 and the second end part B2 are displaced to the other side in the predetermined direction with respect to a virtual bisector BS of a virtual line segment LS which connects a first base end A1 of the first positive electrode tag 132A and a second base end A2 of the second negative electrode tag 134B.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a battery module. [Background technology]

[0002] 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 are pulled out from the exterior material.

[0003] Patent Document 1 describes an example of a battery module. In this battery module, positive and negative electrode tabs are drawn out from opposite sides of an exterior material. In this battery module, the positive electrode tab of a single battery cell or a plurality of battery cells connected in parallel is joined to the negative electrode tab of a single battery cell or a plurality of battery cells connected in parallel. The positive and negative electrode tabs are folded back between the battery cell provided with the positive electrode tab and the battery cell provided with the negative electrode tab.

[0004] Patent Document 2 describes an example of a battery module, in which a plurality of tip portions of a plurality of positive electrode tabs or a plurality of negative electrode tabs of a plurality of battery cells are bent in a direction.

[0005] An example of a battery module is described in Patent Document 3. In this battery module, the tips of the positive electrode tab and the negative electrode tab are bent. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2006 / 109610 [Patent Document 2] International Publication No. 2016 / 020999 [Patent Document 3] International Publication No. 2011 / 027817 Summary of the Invention [Problem to be solved by the invention]

[0007] For example, as described in Patent Document 1, the positive electrode tab and the negative electrode tab may be folded back between at least one battery cell and at least one other battery cell. However, in this case, the workability for connecting at least one battery cell and at least one other battery cell in series may be reduced.

[0008] One example of an object of the present invention is to improve the workability for 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. [Means for solving the problem]

[0009] One aspect of the present invention is as follows. [1] at least one positive electrode tab in which a predetermined first tip portion is 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, with 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 to each other; 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: [Effects of the Invention]

[0010] According to the above-described aspect of the present invention, it is possible to improve the workability for connecting at least one battery cell and at least another battery cell in series. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 2 is a perspective view of a front portion of the battery module according to the embodiment. [Figure 2] 2 is a cross-sectional view along AA' in FIG. [Figure 3] 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; [Figure 4] 5A to 5C are diagrams illustrating a first example of a method for manufacturing a battery module according to an embodiment. [Figure 5] 5A to 5C are diagrams illustrating a first example of a method for manufacturing a battery module according to an embodiment. [Figure 6] 5A to 5C are diagrams illustrating a first example of a method for manufacturing a battery module according to an embodiment. [Figure 7] 10A to 10C are diagrams illustrating a manufacturing method of a battery module according to a comparative example. [Figure 8] 10A to 10C are diagrams illustrating a method for manufacturing a battery module according to a comparative example. [Figure 9]10A and 10B are diagrams illustrating a second example of the method for manufacturing the battery module according to the embodiment. [Figure 10] 10A and 10B are diagrams illustrating a second example of the method for manufacturing the battery module according to the embodiment. [Figure 11] FIG. 10 is a top view of the front portion of the battery module according to Modification 1. [Figure 12] FIG. 10 is a top view of the front portion of a battery module according to Modification 2. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by similar reference numerals, and the description thereof will be omitted as appropriate.

[0013] Fig. 1 is a perspective view of the front part of a battery module 10 according to an embodiment, and Fig. 2 is a cross-sectional view taken along line AA' in Fig. 1.

[0014] For ease 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 refer to the rear side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the X direction will refer to 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 refer to the left side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the Y direction will refer to 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 refer to the upper side of the battery module 10. Unless otherwise specified, the base end of an arrow indicating the Z direction will refer to the lower side of the battery module 10. 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-rear direction, left-right direction, and up-down direction of the battery module 10 is not limited to the above example. These relationships will differ depending on the actual arrangement of the battery module 10.

[0015] The battery module 10 will be described with reference to FIG. 1 and, if necessary, with reference to FIG.

[0016] The battery module 10 includes a plurality of battery cells 100 and a voltage detection unit 200 .

[0017] In the example shown in FIG. 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 FIG. 1. The multiple battery cells 100 are stacked in the Y direction. In the example shown in FIG. 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 FIG. 1.

[0018] As shown in FIGS. 1 and 2, each battery cell 100 includes a battery element 110, an exterior material 120, a positive electrode tab 132, and a negative electrode tab .

[0019] 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 the plurality of negative electrodes 114 are alternately stacked in the Y direction. The positive electrodes 112 and the negative electrodes 114 adjacent to each other in the Y direction are separated from each other by a separator (not shown). However, the structure of the battery element 110 is not limited to this example.

[0020] As shown in FIG. 2, the exterior material 120 seals the battery element 110 and the electrolyte solution (not shown).

[0021] The positive electrode tab 132 is electrically connected to the plurality of positive electrodes 112. The electrical connection between the positive electrode tab 132 and the plurality of 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. A 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 to the right from the base end A when viewed from above. The positive electrode tab 132 is joined to the plurality of positive electrode current collector foils 112a. In the example shown in FIG. 2, the plurality of positive electrode current collector foils 112a are pulled out from the plurality of positive electrodes 112 toward the front of the battery element 110 and are integrally bundled together near the base end A of the positive electrode tab 132. In this way, the positive electrode tab 132 is electrically connected to the plurality of positive electrodes 112. As in the example shown in FIG. 2, the negative electrode tab 134 is electrically connected to the plurality of negative electrodes 114 via a plurality of negative electrode current collecting foils (not shown) drawn out from the plurality of negative electrodes 114 .

[0022] In each battery cell 100, the positive electrode tab 132 and the negative electrode tab 134 are drawn out 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.

[0023] 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 includes a first joint 150. The positive electrode tabs 132 and the negative electrode tabs 134 included in each tab group 130 are joined to each other at the first joint 150. The first joint portion 150 is formed by, for example, laser welding, but the method for forming the first joint portion 150 is not limited to this example.

[0024] A plurality of tab groups 130 located in front of the plurality of battery cells 100 and a 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, the battery cells 100 adjacent to each other 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.

[0025] Each of the multiple voltage detection units 200 is joined to each of the multiple tip group BG. 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 by, for example, laser welding. However, the method of forming the second joint 250 is not limited to this example.

[0026] A plurality of voltage detection lines (not shown) are electrically connected to each of the plurality of voltage detection units 200. Therefore, the voltage of each tab group 130 can be detected by each voltage detection unit 200 and each voltage detection line.

[0027] FIG. 3 is a top view of the front portions of a first battery cell 100A and a second battery cell 100B among the plurality of battery cells 100 according to the embodiment.

[0028] 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.

[0029] 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 portion 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 portion B2, and a second bent portion C2. The first positive electrode tab 132A and the second negative electrode tab 134B form a tab group 130. The first tip portion B1 and the second tip portion B2 form a tip portion group BG.

[0030] FIG. 3 shows an imaginary line segment LS and an 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 a perpendicular bisector of the imaginary line segment LS. When viewed from above, the imaginary bisector BS is approximately parallel to the X direction.

[0031] When viewed from above, the first tip B1 is bent leftward around the first bent portion C1. When viewed from above, the second tip B2 is bent leftward around the second bent portion C2. When viewed from above, the first bent portion C1 and the second bent portion C2 are shifted to the right with respect to the imaginary bisector BS. In other words, the first bent portion C1 and the second bent portion 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.

[0032] When viewed from above, the portion between the first base end A1 and the first bent portion 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 bent portion 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 bent portion C1 and the second bent portion 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.

[0033] In the 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 the 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 of the first positive electrode tab 132A and the length of the second bent portion C2 of the second negative electrode tab 134B and the length of the second bent portion C2 of the second negative electrode tab 134B. For this reason, in the 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 the 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.

[0034] 3, the tip group BG is bent leftward when viewed from above. However, the tip group BG may also be bent rightward when viewed from above. In this case, the first bent portion C1 and the second bent portion C2 can be shifted leftward with respect to the virtual bisector BS.

[0035] 4 to 6 are diagrams illustrating a first example of a method for manufacturing the battery module 10 according to the embodiment. In this first example, the battery module 10 according to the embodiment is manufactured as follows.

[0036] 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.

[0037] Next, the first tip portion B1 and the second tip portion B2 are 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 in the embodiment, a laser can be irradiated 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.

[0038] The order of the steps of joining the first tip portion B1 and the second negative electrode tab 134B is not limited to the above example. For example, the first tip portion B1 and the second tip portion B2 may be joined after being bent as described below.

[0039] Next, as shown in FIG. 4, the first tip portion B1 and the second tip portion B2 are sandwiched between a pair of bending fingers 300A.

[0040] Next, as shown in Fig. 5, the pair of bending fingers 300A are rotated clockwise when viewed from above. As a result, the first tip portion B1 and the second tip portion B2 are bent 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.

[0041] Next, the 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 on the left side of the tip group BG when viewed from above. In this embodiment, the plurality of 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, the tip groups BG of the tab groups 130 adjacent in the Y direction are both bent toward the left when viewed from above. In this example, the width of the space in the Y direction between the tip groups BG adjacent in the Y direction can be made wider than 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. 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 the embodiment, the workability for removing the pair of bent fingers 300A from the tab group 130 can be improved.

[0042] 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 the 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 formed in the first laser finger 410A. This forms the second bonding portion 250, bonding the voltage detection unit 200 to the tip group BG.

[0043] 6, when viewed from above, a space is provided on the left side 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 arranging the second laser finger 420A behind the tip group BG.

[0044] The order of the steps of joining the voltage detection unit 200 to the tip group BG is not limited to the above example. For example, the voltage detection unit 200 may be joined to the tip group BG before the tip group BG is bent.

[0045] 7 and 8 are diagrams for explaining a manufacturing method of a battery module according to a comparative embodiment. The manufacturing method of the battery module according to the comparative embodiment is the same as the manufacturing method of the battery module 10 according to the embodiment, except for the following points.

[0046] First, the first battery cell 100A and the second battery cell 100B are arranged in the X direction with the first tip portion B1 and the second tip portion B2 overlapping in the Y direction.

[0047] 7, the first tip portion B1 and the second tip portion 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 portion 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 portion B2 is sandwiched between a pair of third bending fingers 330K.

[0048] Next, with the positions 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, whereby 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 is bent at a substantially right angle when viewed from above.

[0049] 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 as viewed from above. As a result, 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 is bent at a substantially right angle as 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.

[0050] Next, the voltage detection unit 200 is joined to the front surface of the first tip portion B1.

[0051] The embodiment shown in FIGS. 4 to 6 will be compared with the comparative embodiment shown in FIGS.

[0052] In the comparative example, the shorter the distance in the Y direction between the first base end A1 and the second base end A2 of the folded tab group 130K, the thinner the widths 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 bending tendency of each finger in the Z direction. Therefore, in the comparative example, the shorter the distance in the Y direction 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 portion B1 and the second tip portion B2 can be bent regardless of the distance in the Y direction between the first base end A1 and the second base end A2. Therefore, in the embodiment, the workability of bending the tip portion group BG can be improved compared to the comparative example.

[0053] In the comparative example, the first bending finger 310K, the second bending finger 320K, and the third bending finger 330K located inside the folding tab group 130K must be moved upward or downward to remove these fingers. In contrast, in the embodiment, the bending finger 300A located behind the tip group BG can be removed through the space between the tip group BG adjacent to each other in the Y direction. Therefore, in the embodiment, the bending finger 300A located behind the tip group BG can be removed without moving the bending finger 300A up or downward. Therefore, in the embodiment, the workability for removing the bending finger 300A located behind the tip group BG can be improved compared to the comparative example.

[0054] 9 and 10 are diagrams illustrating a second example of the method for manufacturing the battery module 10 according to the embodiment. The second example shown in Fig. 9 and 10 is similar to the first example shown in Fig. 4 to Fig. 6 except for the following points.

[0055] As shown in FIG. 9 , the portion of the first positive electrode tab 132A between the first tip portion B1 and the first base end A1 and the portion of the second negative electrode tab 134B between the second tip portion B2 and the second base end A2 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 located on the left side of the first positive electrode tab 132A. When viewed from above, the second fixed bending finger 314B is located on the right side of the second negative electrode tab 134B. Next, when viewed from above, the movable bending finger 320B is located in front of the second fixed bending finger 314B and to the right of the second tip portion B2.

[0056] Next, as shown in Figure 10, movable bending finger 320B is rotated clockwise when viewed from above, which causes tip group BG to bend leftward when viewed from above.

[0057] 11 is a top view of the front portion of a 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.

[0058] In Modification 1, when viewed from above, the tip portion 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, 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.

[0059] 12 is a top view of the front portion of a 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.

[0060] A 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.

[0061] 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 , a voltage detection unit 200 is joined to the front surface of the tip group BG. In the second modification, as in the embodiment, the workability for 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.

[0062] In the example shown in Fig. 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 Fig. 12 can be adopted.

[0063] Although the embodiments of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various other configurations can also be adopted. [Explanation of symbols]

[0064] 10, 10A, 10B battery module 100 battery cells 100A 1st battery cell 100B Second Battery Cell 110 Battery element 112 Positive electrode 112a Positive electrode current collector foil 114 Negative electrode 120 Exterior materials 130 Tabs 130K folded tabs 132 Positive electrode tab 132A 1st positive tab 134 Negative electrode tab 134B Second negative electrode tab 150 1st joint 200 Voltage detection unit 250 2nd joint 300A bent finger 310K First bending finger 312B First fixed bending finger 314B Second fixed bending finger 320B Movable bending finger 320K Second bending finger 330K 3rd bending finger 410A First Laser Finger 412A Laser hole 420A Second Laser Finger A proximal end A1 First base end A2 2nd proximal end B1 1st tip B2 2nd tip BG tip group BS Virtual bisector C1 1st bending part C2 2nd bending part LS Virtual Line Segment

Claims

1. 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.

2. The battery module according to claim 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 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.

4. The battery module according to claim 3 , further comprising 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.

5. 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.

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