Battery cell and battery module

Abstract

A battery cell (100A) is provided with a positive electrode tab (110A). The positive electrode tab (110A) has a first base section (111A), a first upper end section (112A), the thickness of which decreases as the distance from the first base section (111A) increases, and a first upper protruding section (114A), which is located between the first base section (111A) and the first upper end section (112A) and which protrudes further outward than the first base section (111A).

Description

Technical Field

[0001] The invention relates to a battery unit and a battery module. Background Art

[0002] In recent years, various battery cells having battery elements such as lithium ion secondary batteries have been developed. The battery elements are sealed by an outer packaging material. Tabs such as positive electrode tabs and negative electrode tabs are drawn out from the outer packaging material.

[0003] An example of a tab of a battery cell is described in Patent Document 1. Both ends of the tab in the width direction are tapered.

[0004] An example of a tab of a battery cell is described in Patent Document 2. The tab includes a copper strip and a nickel plating layer covering the copper strip. The thickness of the nickel plating layer is locally thicker at both ends in the width direction of the copper strip.

[0005] An example of a method for manufacturing a tab of a battery cell is described in Patent Document 3. In this method, a drawn wire is rolled by a roller to form a tab.

[0006] An example of laser welding is described in Patent Document 4. In this method, two members are joined to each other by laser welding in a state where the two members are opposed to each other with a gap therebetween.

[0007] Prior Art Literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent Application Publication No. 2013-243015

[0010] Patent Document 2: Japanese Patent Application Publication No. 2016-134297

[0011] Patent Document 3: Japanese Patent Application Publication No. 2008-204902

[0012] Patent Document 4: Japanese Patent Application Laid-Open No. 59-133985 Summary of the invention

[0013] Problems to be solved by the invention

[0014] Sometimes, the tab of a battery cell is joined to another tab, a bus bar, or other joining object by laser welding. In this case, as described in Patent Document 4, in order to firmly join the tab to the joining object, the laser is sometimes irradiated while the tab and the joining object are facing each other with a gap therebetween. However, if the tab and the joining object are simply facing each other, it is sometimes difficult to form an appropriate gap between the tab and the joining object.

[0015] One example of the purpose of the present invention is to firmly join a tab and a joining object to each other. Other purposes of the present invention will become clear from the description of this specification.

[0016] Means for solving problems

[0017] One embodiment of the present invention is as follows. [1]

[0019] A battery cell includes: a tab having a base; an end portion whose thickness decreases as it moves away from the base; and a protrusion portion located between the base and the end portion and extending outward from the base. [2]

[0021] In the battery cell described in [1], the tab further includes another protrusion that faces the opposite side of the protrusion and extends outward from the base. [3]

[0023] A battery module comprising: a battery cell as described in [1] or [2]; and at least one other battery cell having at least one other electrode tab, wherein the base and the at least one other electrode tab are joined to each other in a state where the protrusion and the at least one other electrode tab are in contact with each other. [4]

[0025] A battery cell includes a tab having a base portion to be joined to a joining object and a protrusion portion extending outward from the base portion and contacting the joining object. [5]

[0027] In the battery cell described in [4], the tab further has another protrusion that faces the opposite side of the protrusion and extends outward from the base. [6]

[0029] A battery module includes the battery cell according to [4] or [5] and at least one other battery cell having at least one other tab as the joining object.

[0030] Effects of the Invention

[0031] According to the above aspect of the present invention, the tab and the object to be joined can be firmly joined to each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a plan view of a portion of the battery module according to the first embodiment.

[0033] Figure 2 yes Figure 1 AA′ cross-sectional view.

[0034] Figure 3 It is a diagram for explaining the joining of the positive electrode tab and the conductor.

[0035] Figure 4 It is a cross-sectional view of a junction between a plurality of positive electrode tabs and a plurality of negative electrode tabs in a battery module according to a modification.

[0036] Figure 5 This is a diagram for explaining an example of a method for manufacturing a positive electrode tab according to the first embodiment.

[0037] Figure 6 It is a cross-sectional view of a junction between a positive electrode tab and a negative electrode tab in a battery module according to a second embodiment.

[0038] Figure 7 It is a cross-sectional view of a junction between a positive electrode tab and a negative electrode tab in a battery module according to a third embodiment. DETAILED DESCRIPTION

[0039] Hereinafter, the embodiment and modification of the present invention will be described using the drawings. In all the drawings, the same components are denoted by the same reference numerals, and the description thereof will be appropriately omitted.

[0040] Figure 1 This is a plan view of a portion of the battery module 10A according to the first embodiment.

[0041] exist Figure 1 In the figure, the X direction, Y direction, and Z direction are marked for the convenience of explanation. The white circle with a black dot indicating the Z direction indicates that the arrow indicating the Z direction extends from the inner side of the paper toward the front. The X direction, Y direction, and Z direction are the front-to-back direction, left-to-right direction, and up-to-down direction of the battery module 10A, respectively. The X direction, Y direction, and Z direction are orthogonal to each other. The arrow indicating the X direction, the arrow indicating the Y direction, and the arrow indicating the Z direction respectively indicate the front direction, the left direction, and the up direction of the battery module 10A. However, the relationship between the X direction, the Y direction, the Z direction, the front-to-back direction, the left-to-right direction, and the up-to-down direction of the battery module 10A is not limited to the above example.

[0042] Hereinafter, a plane perpendicular to the X direction is referred to as a YZ plane as needed. Hereinafter, a plane perpendicular to the Y direction is referred to as a ZX plane as needed. Hereinafter, a plane perpendicular to the Z direction is referred to as an XY plane as needed.

[0043] The battery module 10A includes a plurality of battery cells 100A. The plurality of battery cells 100A are stacked substantially parallel to the Y direction. Each battery cell 100A includes a battery element 102, an exterior material 104, a positive electrode tab 110A, and a negative electrode tab 120A.

[0044] The battery element 102 is in a substantially rectangular parallelepiped shape. The long side direction of the battery element 102 is substantially parallel to the X direction. The short side direction of the battery element 102 is substantially parallel to the Z direction. The thickness direction of the battery element 102 is substantially parallel to the Y direction. In one example, the battery element 102 includes a plurality of positive electrodes and a plurality of negative electrodes (not shown) alternately stacked in the Y direction, and a separator (not shown) located between the positive electrodes and the negative electrodes adjacent in the Y direction. However, the structure of the battery element 102 is not limited to this example.

[0045] The exterior material 104 seals the battery element 102. The exterior material 104 includes, for example, a laminate film.

[0046] The positive electrode tab 110A is led out from the exterior material 104 at one of the front end and the rear end of the battery cell 100A. The front end of the positive electrode tab 110A is bent substantially parallel to the Y direction. The positive electrode tab 110A is electrically connected to the positive electrode (not shown) of the battery element 102. The positive electrode tab 110A contains a metal such as aluminum, for example.

[0047] The negative electrode tab 120A is led out from the outer packaging material 104 at the other of the front end and the rear end of the battery cell 100A. The front end of the negative electrode tab 120A is bent substantially parallel to the Y direction. The negative electrode tab 120A is electrically connected to the negative electrode (not shown) of the battery element 102. The negative electrode tab 120A contains metal such as copper, for example.

[0048] In Embodiment 1, a plurality of battery cells 100A are connected in series. Specifically, in front of or behind adjacent battery cells 100A in the Y direction, the front end of the positive electrode tab 110A of one battery cell 100A overlaps and joins with the front end of the negative electrode tab 120A of another battery cell 100A in a manner substantially parallel to each other in the X direction. The joining portions of the front end of the positive electrode tab 110A and the front end of the negative electrode tab 120A are alternately arranged in front of and behind the battery module 10A. Figure 1 In the example shown, the negative electrode tab 120A is located in front of the positive electrode tab 110A at the front joint of the battery module 10A, and the positive electrode tab 110A is located behind the negative electrode tab 120A at the rear joint of the battery module 10A.

[0049] Figure 2 yes Figure 1 AA' section view. Figure 2 In the figure, a white circle with a black dot indicating the Y direction indicates that an arrow indicating the Y direction extends from the back side of the paper toward the front.

[0050] The following describes the AA′ cross section of the positive electrode tab 110A and the negative electrode tab 120A. That is, the cross section perpendicular to the Y direction of the junction between the front end of the positive electrode tab 110A and the front end of the negative electrode tab 120A is described. The cross section of the front end of the positive electrode tab 110A is also substantially the same as the AA′ cross section in other cross sections perpendicular to the extension direction of the positive electrode tab 110A. Similarly, the cross section of the front end of the negative electrode tab 120A is also substantially the same as the AA′ cross section in other cross sections perpendicular to the extension direction of the negative electrode tab 120A.

[0051] The positive electrode tab 110A includes a first base portion 111A, a first upper end portion 112A, a first lower end portion 113A, a pair of first upper protrusions 114A, and a pair of first lower protrusions 115A.

[0052] The thickness of the first base portion 111A in the X direction is substantially constant regardless of the position in the Z direction. The front and rear surfaces of the first base portion 111A are substantially parallel to the YZ plane. The thickness T1 of the first base portion 111A in the X direction is, for example, not less than 0.15 mm and not more than 1.0 mm.

[0053] The first upper end portion 112A has a substantially tapered shape. Specifically, the thickness of the first upper end portion 112A in the X direction decreases as it moves upward from the first base portion 111A. Figure 2 In the example shown, the front surface of the first upper end portion 112A is inclined toward the rear as it goes upward. The rear surface of the first upper end portion 112A is inclined toward the front as it goes upward. In this case, the first upper end portion 112A can be easily sealed with the exterior material 104, compared with the case where the thickness of the first upper end portion 112A in the X direction is substantially constant regardless of the position in the Z direction. Therefore, in Embodiment 1, the sealing performance of the exterior material 104 can be improved, compared with the case where the thickness of the first upper end portion 112A in the X direction is substantially constant regardless of the position in the Z direction.

[0054] The first lower end portion 113A has a substantially tapered shape. Specifically, the thickness of the first lower end portion 113A in the X direction decreases as it moves downward from the first base portion 111A. Figure 2 In the example shown, the front surface of the first lower end portion 113A is inclined toward the rear as it goes downward. The rear surface of the first lower end portion 113A is inclined toward the front as it goes downward. In this case, the first lower end portion 113A can be easily sealed with the exterior material 104, compared with the case where the thickness of the first lower end portion 113A in the X direction is substantially constant regardless of the position in the Z direction. Therefore, in Embodiment 1, the sealing performance of the exterior material 104 can be improved, compared with the case where the thickness of the first lower end portion 113A in the X direction is substantially constant regardless of the position in the Z direction.

[0055] exist Figure 2 In the example shown, the cross-sectional shape of the first upper end portion 112A and the cross-sectional shape of the first lower end portion 113A are substantially symmetrical. However, the cross-sectional shape of the first upper end portion 112A and the cross-sectional shape of the first lower end portion 113A may be asymmetrical. Alternatively, the width in the X direction of one of the first upper end portion 112A and the first lower end portion 113A may be substantially constant regardless of the position in the Z direction.

[0056] A pair of first upper protrusions 114A are located between the first base 111A and the first upper end 112A in the Z direction. The pair of first upper protrusions 114A extend outward further than the first base 111A in the X direction. Specifically, the first upper protrusion 114A on the front side extends further forward than the front surface of the first base 111A. The first upper protrusion 114A on the front side is bent convexly forward. The first upper protrusion 114A on the rear side extends further backward than the rear surface of the first base 111A. The first upper protrusion 114A on the rear side is bent convexly backward. The maximum thickness T2 in the X direction of the portion of the positive electrode tab 110A where the pair of first upper protrusions 114A are provided is, for example, greater than T1+10μm and less than T1+200μm, and preferably greater than T1+30μm and less than T1+100μm.

[0057] The cross-sectional shape of each first upper protrusion 114A is not limited to this example. Figure 2 In the example shown, the cross-sectional shapes of the pair of first upper protrusions 114A are substantially symmetrical. However, the cross-sectional shapes of the pair of first upper protrusions 114A may be asymmetrical.

[0058] A pair of first lower protrusions 115A are located between the first base 111A and the first lower end 113A in the Z direction. The pair of first lower protrusions 115A extend outward further than the first base 111A in the X direction. Specifically, the first lower protrusion 115A on the front side extends further forward than the front surface of the first base 111A. The first lower protrusion 115A on the front side is bent convexly forward. The first lower protrusion 115A on the rear side extends further backward than the rear surface of the first base 111A. The first lower protrusion 115A on the rear side is bent convexly backward. The maximum thickness in the X direction of the portion of the positive electrode tab 110A where the pair of first lower protrusions 115A are provided may be equal to the above-mentioned maximum thickness T2, or may be different.

[0059] The cross-sectional shape of each first lower protrusion 115A is not limited to this example. Figure 2 In the example shown, the cross-sectional shapes of the pair of first lower protrusions 115A are substantially symmetrical. However, the cross-sectional shapes of the pair of first lower protrusions 115A may be asymmetrical.

[0060] The height Δ of the front end of the first upper protrusion 114A relative to the front surface of the first base 111A in the X direction is, for example, greater than 0 and less than 250 μm. The height of the rear end of the first upper protrusion 114A on the rear side relative to the rear surface of the first base 111A in the X direction may be equal to or different from the height Δ. The height of the front end of the first lower protrusion 115A on the front side relative to the front surface of the first base 111A in the X direction may be equal to or different from the height Δ. The height of the rear end of the first lower protrusion 115A on the rear side relative to the rear surface of the first base 111A in the X direction may be equal to or different from the height Δ.

[0061] The difference T2-T1 between the maximum thickness T2 in the X direction of the portion of the positive electrode tab 110A provided with the pair of first upper protrusions 114A and the thickness T1 in the X direction of the first base portion 111A is, for example, greater than 0 and less than 200 μm, preferably greater than 0 and less than 100 μm. The difference between the thickness in the X direction of the portion of the positive electrode tab 110A provided with the pair of first lower protrusions 115A and the thickness T1 in the X direction of the first base portion 111A may be equal to the difference T2-T1, or may be different.

[0062] The negative electrode tab 120A includes a second base portion 121A, a second upper end portion 122A, a second lower end portion 123A, a pair of second upper protrusions 124A, and a pair of second lower protrusions 125A, similarly to the positive electrode tab 110A. In Embodiment 1, the cross-sectional shape of the negative electrode tab 120A is substantially the same as the cross-sectional shape of the positive electrode tab 110A. However, the cross-sectional shape of the negative electrode tab 120A may be different from the cross-sectional shape of the positive electrode tab 110A.

[0063] The first base portion 111A and the second base portion 121A are joined to each other through a molten portion 130A. The molten portion 130A is formed by laser welding. In the laser welding, a laser is irradiated from the front of the negative electrode tab 120A toward the front surface of the negative electrode tab 120A. Therefore, the laser irradiated portion of the negative electrode tab 120A and the laser irradiated portion of the positive electrode tab 110A are melted to form the molten portion 130A.

[0064] In Embodiment 1, the first upper protrusion 114A on the front side and the second upper protrusion 124A on the rear side are in contact with each other. Similarly, the first lower protrusion 115A on the front side and the second lower protrusion 125A on the rear side are in contact with each other. Therefore, the first base 111A and the second base 121A are joined to each other in a state where the first upper protrusion 114A on the front side and the second upper protrusion 124A on the rear side are in contact with each other and the first lower protrusion 115A on the front side and the second lower protrusion 125A on the rear side are in contact with each other. In a state where the first upper protrusion 114A on the front side and the second upper protrusion 124A on the rear side are in contact with each other and the first lower protrusion 115A on the front side and the second lower protrusion 125A on the rear side are in contact with each other, a gap 150A is formed between the front surface of the first base 111A and the rear surface of the second base 121A. In the gap 150A, a portion of the melting portion 130A extends substantially parallel to the YZ plane. Therefore, compared with a case where the front surface of the first base 111A and the rear surface of the second base 121A are in contact with each other, the bonding area of ​​the melting portion 130A between the front surface of the first base 111A and the rear surface of the second base 121A can be increased by the amount by which the melting portion 130A extends in the gap 150A. Therefore, in Embodiment 1, compared with a case where the front surface of the first base 111A and the rear surface of the second base 121A are in contact with each other, the first base 111A and the second base 121A can be firmly bonded to each other.

[0065] In Embodiment 1, the width of the gap 150A in the X direction can be adjusted by the height of the first upper protrusion 114A and the first lower protrusion 115A on the front side relative to the front surface of the first base 111A in the X direction, and the height of the second upper protrusion 124A and the second lower protrusion 125A on the rear side relative to the rear surface of the second base 121A in the X direction. Therefore, by adjusting the heights of these protrusions, the width of the gap 150A in the X direction can be set to a width appropriate for laser welding.

[0066] In Embodiment 1, a pair of first upper protrusions 114A extend to opposite sides in the Y direction. The same is true for a pair of first lower protrusions 115A, a pair of second upper protrusions 124A, and a pair of second lower protrusions 125A. Therefore, even when the positions of the positive electrode tab 110A and the negative electrode tab 120A are interchanged in the X direction, a gap can be formed between the rear surface of the first base 111A and the front surface of the second base 121A. Depending on the battery module 10A, at the junction of the positive electrode tab 110A and the negative electrode tab 120A, the positive electrode tab 110A is sometimes arranged in front of the negative electrode tab 120A. Therefore, according to the positive electrode tab 110A and the negative electrode tab 120A according to Embodiment 1, the first base portion 111A and the second base portion 121A can be firmly joined to each other regardless of the arrangement of the positive electrode tab 110A and the negative electrode tab 120A in the X direction. Therefore, the assemblability of the battery module 10A can be improved.

[0067] In Embodiment 1, the protrusions of the positive electrode tab 110A are provided on both sides of the first base 111A in the Z direction. Therefore, compared with the case where the protrusions are provided on only one of the two sides of the first base 111A in the Z direction, the width of the gap 150A in the X direction between the positive electrode tab 110A and the negative electrode tab 120A can be stably set. However, the protrusions may be provided on only one side of the first base 111A in the Z direction. The same is true for the protrusions of the negative electrode tab 120A.

[0068] The cross-sectional shape of the positive electrode tab 110A and the cross-sectional shape of the negative electrode tab 120A are not limited to Figure 2 Example shown.

[0069] For example, the rear surface of the positive electrode tab 110A and the front surface of the negative electrode tab 120A may also be substantially parallel to the YZ plane. In this case, the first upper protrusion 114A and the first lower protrusion 115A may also be provided only on the front surface of the positive electrode tab 110A. That is, the first upper protrusion 114A and the first lower protrusion 115A may also be provided only on the surface of the positive electrode tab 110A that is opposite to the negative electrode tab 120A. In contrast, the second upper protrusion 124A and the second lower protrusion 125A may also be provided only on the rear surface of the negative electrode tab 120A. That is, the second upper protrusion 124A and the second lower protrusion 125A may also be provided only on the surface of the negative electrode tab 120A that is opposite to the positive electrode tab 110A. In this case as well, the gap 150A can be formed between the front surface of the first base portion 111A and the rear surface of the second base portion 121A.

[0070] Alternatively, one of the positive electrode tab 110A and the negative electrode tab 120A may not have a protrusion. In this example, the protrusion is provided on the front surface of the positive electrode tab 110A or the rear surface of the negative electrode tab 120A. In other words, the protrusion is provided on one of the surface of the positive electrode tab 110A that faces the negative electrode tab 120A and the surface of the negative electrode tab 120A that faces the positive electrode tab 110A. In this case, a gap 150A can also be formed between the front surface of the first base 111A and the rear surface of the second base 121A.

[0071] Figure 3 It is a diagram for explaining the joining of the positive electrode tab 110A and the conductor 200 .

[0072] exist Figure 2 In the example shown, the negative electrode tab 120A is the object to be joined to the positive electrode tab 110A. However, the object to be joined to the positive electrode tab 110A is not limited to the negative electrode tab 120A. Figure 3 As shown, the object to be joined to the positive electrode tab 110A may be a conductor 200 substantially parallel to the YZ plane. As the conductor 200, for example, a bus bar that connects the battery module 10A to an external battery module (not shown) is exemplified.

[0073] exist Figure 3 In the example shown, the first upper protrusion 114A and the first lower protrusion 115A on the side where the conductor 200 is located are in contact with the conductor 200. Therefore, the first base 111A and the conductor 200 are joined to each other in a state where the first upper protrusion 114A and the first lower protrusion 115A on the side where the conductor 200 is located are in contact with the conductor 200. In a state where the first upper protrusion 114A and the first lower protrusion 115A on the side where the conductor 200 is located are in contact with the conductor 200, a gap 250 is formed between the mutually opposing surfaces of the first base 111A and the conductor 200. In other words, the first base 111A and the conductor 200 are opposed to each other with the gap 250 therebetween. Therefore, when using Figure 2 As described above, the first base portion 111A and the conductor 200 can be more firmly joined to each other by laser welding than in the case where the first base portion 111A and the conductor 200 are in contact with each other.

[0074] exist Figure 3 In the above, the joining of the positive electrode tab 110A and the conductor 200 is described. Figure 3 The matters described above can also be applied similarly to the joining of the negative electrode tab 120A and the conductor 200 .

[0075] Figure 41 is a cross-sectional view of a junction between a plurality of positive electrode tabs 110A and a plurality of negative electrode tabs 120A in a battery module 101A according to a modification. The battery module 10A1 according to the modification is the same as the battery module 10A according to the embodiment except for the following points.

[0076] In a modified example, a plurality of positive electrode tabs 110A led out from a plurality of battery cells 100A connected in parallel are joined to a plurality of negative electrode tabs 120A led out from a plurality of other battery cells 100A connected in parallel. Figure 4 In the example shown, two positive electrode tabs 110A led out from two battery cells 100A connected in parallel and two negative electrode tabs 120A led out from two other battery cells 100A connected in parallel are joined to each other via a fusion zone 130A1. However, three or more positive electrode tabs 110A and three or more negative electrode tabs 120A may be joined to each other.

[0077] Each positive electrode tab 110A includes a pair of first upper protrusions 114A and a pair of first lower protrusions 115A. Each negative electrode tab 120A includes a pair of second upper protrusions 124A and a pair of second lower protrusions 125A. Between the tabs adjacent in the X direction, the protrusions are in contact with each other. Therefore, the tabs adjacent in the X direction are joined to each other in a state where the protrusions are in contact with each other between the tabs adjacent in the X direction. In a state where the protrusions are in contact with each other between the tabs adjacent in the X direction, a gap is formed between the mutually opposing surfaces of the tabs adjacent in the X direction. Therefore, as described in Embodiment 1, compared with the case where the mutually opposing surfaces of the tabs adjacent in the X direction are in contact with each other, the tabs adjacent in the X direction can be firmly joined to each other.

[0078] Figure 5 1 is a diagram for explaining an example of a method for manufacturing the positive electrode tab 110A according to the first embodiment. Figure 5 In FIG. 1 , the arrow indicating the Z direction indicates the upward direction in the vertical direction. The X direction is one of the horizontal directions perpendicular to the Z direction. The Y direction is one of the horizontal directions perpendicular to both the Z direction and the X direction. Figure 5 In the figure, for the purpose of explanation, the positive electrode workpiece 110 is shown through.

[0079] The positive electrode tab 110A is formed by rolling the positive electrode workpiece 110. In the rolling process, a pair of first rollers 502 and a pair of second rollers 504 are used, which are arranged on both sides of the X direction of a given central space 510. Each first roller 502 and each second roller 504 rotates around a rotation axis substantially parallel to the X direction. A pair of first rollers 502 are opposed to each other in the Z direction across the first tapered space 512. The width of the first tapered space 512 in the Z direction decreases as it moves away from the central space 510 in the X direction. A pair of second rollers 504 are opposed to each other in the Z direction across the second tapered space 514. The width of the second tapered space 514 in the Z direction decreases as it moves away from the central space 510 in the X direction.

[0080] The positive electrode workpiece 110 passes through the central space 510, the first tapered space 512, and the second tapered space 514 substantially parallel to the Y direction. The portion of the positive electrode workpiece 110 passing through the central space 510 is formed at the first base 111A. The portion of the positive electrode workpiece 110 passing through the first tapered space 512 is formed at one of the first upper end 112A and the first lower end 113A substantially in accordance with the shape of the first tapered space 512. The portion of the positive electrode workpiece 110 passing through the second tapered space 514 is formed at the other of the first upper end 112A and the first lower end 113A substantially in accordance with the shape of the second tapered space 514.

[0081] exist Figure 5 In the example shown, when one end portion of the positive electrode workpiece 110 in the X direction is compressed by the pair of first rollers 502, the material constituting the one end portion of the positive electrode workpiece 110 in the X direction is pushed out toward the central space 510. As a result, the portion of the positive electrode workpiece 110 located between the central space 510 and the first tapered space 512 partially extends in the Z direction. Therefore, one side of the pair of first upper protrusions 114A and the pair of first lower protrusions 115A is formed. When the other end portion of the positive electrode workpiece 110 in the X direction is also compressed by the pair of second rollers 504, the material constituting the other end portion of the positive electrode workpiece 110 in the X direction is pushed out toward the central space 510. Therefore, for the same reason as the above, the other side of the pair of first upper protrusions 114A and the pair of first lower protrusions 115A is formed.

[0082] exist Figure 5 In the above description, the method for manufacturing the positive electrode tab 110A is described. The method for manufacturing the negative electrode tab 120A can also be the same as the method for manufacturing the positive electrode tab 110A.

[0083] Figure 6It is a cross-sectional view of a junction between a positive electrode tab 110B and a negative electrode tab 120B in a battery module 10B according to Embodiment 2. The battery module 10B according to Embodiment 2 is the same as the battery module 10A according to Embodiment 1 except for the following points.

[0084] The positive electrode tab 110B according to the second embodiment includes a first base 111B, a pair of first upper protrusions 114B, and a pair of first lower protrusions 115B. The pair of first upper protrusions 114B are provided at the upper end of the first base 111B. The pair of first upper protrusions 114B extend further outward than the first base 111B in the X direction. The pair of first lower protrusions 115B are provided at the lower end of the first base 111B. The pair of first lower protrusions 115B extend further outward than the first base 111B in the X direction.

[0085] The negative electrode tab 120B according to the second embodiment includes a second base 121B, a pair of second upper protrusions 124B, and a pair of second lower protrusions 125B. The pair of second upper protrusions 124B are provided at the upper end of the second base 121B. The pair of second lower protrusions 125B extend outwards from the second base 121B in the X direction. The pair of second lower protrusions 125B are provided at the lower end of the second base 121B. The pair of second lower protrusions 125B extend outwards from the second base 121B in the X direction.

[0086] In the second embodiment, similarly to the first embodiment, the first upper protrusion 114B on the front side and the second upper protrusion 124B on the rear side are in contact with each other. Similarly, the first lower protrusion 115B on the front side and the second lower protrusion 125B on the rear side are in contact with each other. Therefore, the first base 111B and the second base 121B are joined to each other in a state where the first upper protrusion 114B on the front side and the second upper protrusion 124B on the rear side are in contact with each other, and the first lower protrusion 115B on the front side and the second lower protrusion 125B on the rear side are in contact with each other. In a state where the first upper protrusion 114B on the front side and the second upper protrusion 124B on the rear side are in contact with each other, and the first lower protrusion 115B on the front side and the second lower protrusion 125B on the rear side are in contact with each other, a gap 150B is formed between the front surface of the first base 111B and the rear surface of the second base 121B. In the gap 150B, a portion of the molten portion 130B extends substantially parallel to the YZ plane. Therefore, as described in Embodiment 1, compared with the case where the front surface of the first base portion 111B and the rear surface of the second base portion 121B are in contact with each other, the first base portion 111B and the second base portion 121B can be firmly joined to each other.

[0087] Figure 7It is a cross-sectional view of a junction between a positive electrode tab 110C and a negative electrode tab 120C in a battery module 10C according to Embodiment 3. The battery module 10C according to Embodiment 2 is the same as the battery module 10A according to Embodiment 1 except for the following points.

[0088] The positive electrode tab 110C involved in the third embodiment includes a first base 111C, a first upper end 112C, a first lower end 113C, a first upper protrusion 114C, and a first lower protrusion 115C. The rear surfaces of the first base 111C, the first upper end 112C, and the first lower end 113C are substantially parallel to and substantially flush with the YZ plane. The first upper protrusion 114C is located between the first base 111C and the first upper end 112C in the Z direction. The first upper protrusion 114C extends further forward than the front surface of the first base 111C. The first lower protrusion 115C is located between the first base 111C and the first lower end 113C in the Z direction. The first lower protrusion 115C extends further forward than the front surface of the first base 111C.

[0089] The negative electrode tab 120C involved in the third embodiment includes a second base 121C, a second upper end 122C, a second lower end 123C, a second upper protrusion 124C, and a second lower protrusion 125C. The front surfaces of the second base 121C, the second upper end 122C, and the second lower end 123C are substantially parallel to and substantially flush with the YZ plane. The second upper protrusion 124C is located between the second base 121C and the second upper end 122C in the Z direction. The second upper protrusion 124C extends further rearward than the rear surface of the second base 121C. The second lower protrusion 125C is located between the second base 121C and the second lower end 123C in the Z direction. The second lower protrusion 125C extends further rearward than the rear surface of the second base 121C.

[0090] In the third embodiment, similarly to the first embodiment, the first upper protrusion 114C and the second upper protrusion 124C are in contact with each other. Similarly, the first lower protrusion 115C and the second lower protrusion 125C are in contact with each other. Therefore, the first base 111C and the second base 121C are joined to each other in a state where the first upper protrusion 114C and the second upper protrusion 124C are in contact with each other and the first lower protrusion 115C and the second lower protrusion 125C are in contact with each other. In a state where the first upper protrusion 114C and the second upper protrusion 124C are in contact with each other and the first lower protrusion 115C and the second lower protrusion 125C are in contact with each other, a gap 150C is formed between the front surface of the first base 111C and the rear surface of the second base 121C. In the gap 150C, a portion of the molten portion 130C extends substantially parallel to the YZ plane. Therefore, as described in Embodiment 1, the first base portion 111C and the second base portion 121C can be more firmly joined to each other than in the case where the front surface of the first base portion 111C and the rear surface of the second base portion 121C are in contact with each other. Figure 7 As shown, even if the rear surface of the positive electrode tab 110C and the front surface of the negative electrode tab 120C are flat, the gap 150C can be formed by the first upper protrusion 114C, the first lower protrusion 115C, the second upper protrusion 124C, and the second lower protrusion 125C.

[0091] As mentioned above, although embodiment and modification of this invention were described with reference to drawings, these are illustrations of this invention, and various structures other than the above-mentioned can also be adopted.

[0092] This application claims the priority based on Japanese patent application No. 2022-160209 filed on October 4, 2022, and incorporates all the disclosure of that application into this application.

[0093] Explanation of symbols

[0094] 10A, 10A1, 10B, 10C battery module; 100A battery cell; 102 battery element; 104 exterior material; 110 positive electrode workpiece; 110A, 110B, 110C positive electrode tab; 111A, 111B, 111C first base; 112A, 112C first upper end; 113A, 113C first lower end; 114A, 114B, 114C first upper protrusion; 115A, 115B, 115C first lower protrusion; 120A, 120B, 120C negative electrode tab; 121A, 121B, 121C second base; 122A, 122C second upper end; 123A, 123C second lower end; 124A, 124B, 124C second upper protrusion; 125A, 125B, 125C second lower protrusion; 130A, 130A1, 130B, 130C melting portion; 150A, 150B, 150C gap; 200 conductor; 250 gap; 502 first roller; 504 second roller; 510 central space; 512 first tapered space; 514 second tapered space.

Claims

1. A battery cell, With ear tips, The tab includes: a base; an end portion whose thickness decreases as it moves away from the base; and a protrusion portion located between the base portion and the end portion and extending outward from the base portion.

2. The battery cell according to claim 1, wherein: The tab further includes another protrusion that faces the opposite side of the protrusion and extends outward from the base.

3. A battery module comprising: The battery cell according to claim 1 or 2; and at least one other battery cell having at least one other tab, The base portion and the at least one other tab are engaged with each other in a state where the protrusion portion and the at least one other tab are in contact with each other.

4. A battery cell, With ear tips, The tab includes: a base portion to be engaged with an object to be engaged; and a protrusion portion extending outward from the base portion and in contact with the object to be engaged.

5. The battery cell according to claim 4, wherein: The tab further includes another protrusion that faces the opposite side of the protrusion and extends outward from the base.

6. A battery module comprising: The battery cell according to claim 4 or 5; and At least one other battery cell has at least one other tab as the joining object.

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