Busbars and energy storage modules

Abstract

To provide a bus bar in which an electrical connection with an electrode terminal is less likely to be damaged.SOLUTION: A plate-shaped bus bar 20 that connects a plurality of power storage elements 11 includes a plurality of connection portions 21 connected to electrode terminals 12A and 12B of the plurality of power storage elements 11, and one or more intermediate portions 22 connecting adjacent connection portions 21, the connection portion 21 is arranged to face the electrode terminals 12A and 12B and includes an electrode welding portion 23 welded to the electrode terminals 12A and 12B, one or more slits 24 are provided in the intermediate portion 22, and the slit 24 is elongated in the direction in which the connection portions 21 are arranged, and has a predetermined dimension in the width direction orthogonal to both of the arrangement direction and the opposing direction in which the electrode welding portion 23 and the electrode terminals 12A and 12B face each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a bus bar and an energy storage module. [Background technology]

[0002] Energy storage modules for electric vehicles, hybrid vehicles, and the like include a large number of stacked energy storage elements, which are electrically connected in series or parallel by bus bars. A conventionally known example of such a bus bar is the laminated bus bar described in Japanese Patent Laid-Open Publication No. 2021-26946 (Patent Document 1 below). This laminated bus bar includes a conductive, plate-like first substrate having a plurality of first through holes arranged in a row at equal intervals, and a second substrate having a plurality of second through holes arranged in a row at equal intervals. The first substrate and the second substrate are stacked and fixed together. Each of the first through holes and each of the second through holes are arranged opposite each other in the stacking direction of the first substrate and the second substrate. The edge of each second through hole has a thin-walled portion that is welded to an electrode terminal of the energy storage element. The laminated bus bar has bent portions between adjacent thin-walled portions. The bent portions are elastically deformable in the direction in which the first through holes are arranged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-26946 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above configuration, the laminated busbar is less likely to deform in a direction (the short side direction of the laminated busbar) perpendicular to both the stacking direction of the first and second base materials and the arrangement direction of the first through holes. Therefore, if the energy storage element is misaligned in the short side direction of the laminated busbar after the laminated busbar is welded to the energy storage element, stress may be applied to the welded portion between the laminated busbar and the electrode terminal, potentially damaging the connection reliability between the laminated busbar and the electrode terminal. [Means for solving the problem]

[0005] The busbar of the present disclosure is a plate-shaped busbar that connects multiple energy storage elements, and includes multiple connection portions that are connected to electrode terminals of the multiple energy storage elements, and one or more intermediate portions that link adjacent connection portions, the connection portions being arranged opposite the electrode terminals and including electrode welds that are welded to the electrode terminals, and one or more slits being provided in the intermediate portions, the slits having a shape that is elongated in the arrangement direction in which the connection portions are arranged, and having a predetermined dimension in a width direction that is perpendicular to both the arrangement direction and the opposing direction in which the electrode welds and the electrode terminals face each other. [Effects of the Invention]

[0006] According to the present disclosure, it is possible to provide a bus bar that is less likely to lose electrical connection with an electrode terminal. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view of the electricity storage module according to the first embodiment. [Figure 2] FIG. 2 is an enlarged plan view of the energy storage module showing the periphery of the bus bar. [Figure 3] FIG. 3 is a plan view of the bus bar. [Figure 4] FIG. 4 is a perspective view of the bus bar. [Figure 5] FIG. 5 is a front view of the bus bar. [Figure 6] FIG. 6 is an enlarged front view of the bus bar showing the periphery of the angled portion. [Figure 7] FIG. 7 is an exploded perspective view of the bus bar. [Figure 8] FIG. 8 is a perspective view of one substrate. [Figure 9] FIG. 9 is a plan view schematically showing the deformation of the bus bar. [Figure 10] FIG. 10 is a plan view schematically showing a modification of a bus bar that does not fall within the scope of the present disclosure and does not have a slit. [Figure 11] FIG. 11 is a plan view of the bus bar according to the second embodiment. [Figure 12] FIG. 12 is a perspective view of a bus bar. [Figure 13] FIG. 13 is a front view of the bus bar according to the third embodiment. [Figure 14] FIG. 14 is a plan view of the bus bar according to the fourth embodiment. [Figure 15] FIG. 15 is a plan view of the bus bar according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Description of the embodiments of the present disclosure] First, embodiments of the present disclosure will be listed and described.

[0009] (1) The busbar disclosed herein is a plate-shaped busbar that connects a plurality of energy storage elements, and includes a plurality of connection portions that are connected to electrode terminals of the plurality of energy storage elements, and one or more intermediate portions that connect adjacent connection portions, the connection portions being arranged opposite the electrode terminals and including electrode welds that are welded to the electrode terminals, and one or more slits being provided in the intermediate portions, the slits having a shape that is elongated in the direction in which the connection portions are arranged, and having a predetermined dimension in a width direction that is perpendicular to both the arrangement direction and the opposing direction in which the electrode welds and the electrode terminals face each other. Here, the "predetermined dimension" is a dimension that is not recognized as substantially zero, for example, a dimension that allows the edge portions of the slit to be recognized as being spaced apart in the width direction.

[0010] With this configuration, the slits make it easier for the bus bar to deform in the width direction. Therefore, if the energy storage element is misaligned in the width direction, the stress applied to the electrode welds welded to the electrode terminals can be reduced. Therefore, the electrical connection between the bus bar and the electrode terminals is less likely to be impaired.

[0011] (2) It is preferable that a plurality of the slits are provided in each of the intermediate portions and are aligned in the width direction.

[0012] With this configuration, the bus bar becomes more likely to deform in the width direction due to the increased number of slits.

[0013] (3) The intermediate portion is preferably a mountain-shaped portion that protrudes from the connection portion in a direction away from the electrode terminal.

[0014] With this configuration, the provision of the angled portions can absorb tolerances in the arrangement direction. Also, since the length of the busbars arranged between adjacent connection portions is increased, the busbars are more susceptible to deformation in the width direction.

[0015] (4) The mountain-shaped portion preferably comprises a ceiling portion parallel to the connection portion and a connecting portion connecting the ceiling portion and the connection portion, and the connecting portion preferably protrudes in the direction from the ceiling portion toward the connection portion in the arrangement direction as it moves from the connection portion side toward the ceiling portion side. Here, "parallel" includes an arrangement that is recognized as being substantially parallel.

[0016] With this configuration, the connecting portion protrudes toward the connecting portion, which increases the length of the bus bar disposed between adjacent connecting portions, making the bus bar more susceptible to deformation in the width direction.

[0017] (5) The bus bar is preferably configured to include a plurality of plate-shaped base materials stacked in the opposing direction.

[0018] With this configuration, the volume of the bus bar can be easily increased, so that heat generation in the bus bar can be suppressed even when the voltage of the energy storage element increases.

[0019] (6) It is preferable that the busbar is configured with a plurality of plate-shaped substrates stacked in the opposing direction, each of the substrates having a convex portion that constitutes the mountain-shaped portion, and a clearance is provided between adjacent convex portions.

[0020] With this configuration, since a clearance is provided between adjacent protrusions, each protrusion can easily deform independently, which makes it easier for the bus bar to deform in the width direction.

[0021] (7) The present disclosure provides an energy storage module including a plurality of energy storage elements and the bus bar described above connected to electrode terminals of the plurality of energy storage elements.

[0022] With this configuration, it is possible to provide an electricity storage module in which the electrical connection between the bus bars and the electrode terminals is less likely to be impaired.

[0023] [Details of the embodiments of the present disclosure] The present disclosure will be described below with reference to exemplary embodiments. The present disclosure is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope of the claims.

[0024] <Embodiment 1> A first embodiment of the present disclosure will be described with reference to FIGS. 1 to 9. As shown in FIG. 1, an energy storage module 10 of this embodiment includes a plurality of energy storage elements 11 and a bus bar 20 that electrically connects adjacent energy storage elements 11. The energy storage module 10 is mounted on a vehicle, such as an electric vehicle or a hybrid vehicle, as a power source for driving the vehicle. In the following description, the direction indicated by arrow Z is defined as upward, the direction indicated by arrow X as forward, and the direction indicated by arrow Y as leftward. Note that, in some cases, when multiple identical components are used, only some of the components will be designated by reference numerals, and the reference numerals for the other components will be omitted.

[0025] [Electricity storage element, electrode terminal] The energy storage element 11 has a flat rectangular parallelepiped shape and accommodates an energy storage element (not shown) inside. Electrode terminals 12A and 12B are provided on the upper surface of the energy storage element 11. One of the electrode terminals 12A and 12B is a positive electrode, and the other is a negative electrode. The energy storage element 11 is not particularly limited and may be a secondary battery or a capacitor. The energy storage element 11 according to this embodiment is a secondary battery. A plurality of energy storage elements 11 (six in this embodiment) are stacked in the left-right direction, and spacers (not shown) are arranged between adjacent energy storage elements 11. In this embodiment, the energy storage elements 11 are arranged such that the electrode terminals 12A and the electrode terminals 12B are alternately connected in the stacking direction of the energy storage elements 11.

[0026] [Busbar] As shown in Fig. 4, bus bar 20 is made of a conductive metal plate. In more detail, as will be described later, bus bar 20 is made by stacking a plurality of plate-shaped base materials 30 in the vertical direction. Examples of metals that make up bus bar 20 include copper, copper alloy, aluminum, aluminum alloy, and stainless steel (SUS). As shown in Figs. 1 and 2, bus bar 20 is attached to the upper surfaces of adjacent energy storage elements 11 to electrically connect electrode terminals 12A, 12B (i.e., positive and negative electrodes) of adjacent energy storage elements 11.

[0027] [Connections, intermediate sections, electrode welds] As shown in FIG. 2 , the bus bar 20 has two connection portions 21 and an intermediate portion 22 connecting the two connection portions 21. The connection portions 21 are flat and overlap the electrode terminals 12A and 12B. Electrode weld portions 23 are provided on the lower surfaces of the left and right connection portions 21 so as to face the upper surfaces of the electrode terminals 12A and 12B. The electrode weld portions 23 are electrically and physically connected to the upper surfaces of the electrode terminals 12A and 12B by welding. In this embodiment, the connection portions 21 are aligned in the left-right direction, and the electrode weld portions 23 and the electrode terminals 12A and 12B face each other in the up-down direction.

[0028] [slit] As shown in FIG. 2, the bus bar 20 has a slit 24 that penetrates the middle portion 22 in the up-down direction. The slit 24 is located at the center of the bus bar 20 in the front-rear direction. As shown in FIG. 3, the slit 24 is elongated in the left-right direction and has a predetermined dimension in the width direction. In this embodiment, the width direction of the slit 24 is the front-rear direction. Here, the predetermined dimension is a dimension that is not recognized as substantially zero, for example, a dimension that allows the hole edges of the slit 24 to be recognized as being spaced apart in the width direction (front-rear direction). In this embodiment, the dimension LW of the slit 24 in the width direction (front-rear direction, short side direction) is approximately 8% of the dimension LL of the slit 24 in the long side direction (left-right direction).

[0029] [Yamagata area] As shown in FIG. 4 , the intermediate portion 22 of this embodiment is a mountain-shaped portion 25 that protrudes upward, i.e., from the connection portion 21 in a direction away from the electrode terminals 12A and 12B. As shown in FIG. 5 , the mountain-shaped portion 25 has an angular inverted U-shape when viewed from the front. The mountain-shaped portion 25 includes a ceiling portion 26 parallel to the connection portion 21 and two connecting portions 27 connecting the ceiling portion 26 to the connection portion 21. Specifically, the left connecting portion 27 connects the right end of the left connection portion 21 to the left end of the ceiling portion 26, and the right connecting portion 27 connects the left end of the right connection portion 21 to the right end of the ceiling portion 26. The connecting portions 27 are disposed perpendicular to the connection portion 21. Note that in this disclosure, "parallel" and "perpendicular" include arrangements that are recognized as being substantially parallel and perpendicular.

[0030] The angled portions 25 elastically deform to accommodate tolerances in the left-right and up-down directions. Furthermore, the provision of the angled portions 25 allows the length of the busbar 20 disposed between the two electrode weld portions 23 to be longer than when the angled portions 25 are not provided (see the flat busbar 320 shown in FIG. 14). In other words, because the angled portions 25 provide the busbar 20 with an excess length, the busbar 20 can easily deform even when the left and right connection portions 21 are misaligned in the front-to-rear direction (as will be described in detail later).

[0031] As shown in FIG. 3 , the slit 24 penetrates the mountain-shaped portion 25 in the up-down direction. Specifically, the left-right dimension LL of the slit 24 is larger than the left-right dimension of the mountain-shaped portion 25, and the right and left ends of the slit 24 are located closer to the mountain-shaped portion 25 of the connecting portion 21. That is, the mountain-shaped portion 25 is divided in the front-rear direction by the slit 24. The portion of the mountain-shaped portion 25 located in front of the slit 24 is defined as a first mountain-shaped portion 25A. The portion of the mountain-shaped portion 25 located behind the slit 24 is defined as a second mountain-shaped portion 25B. The first mountain-shaped portion 25A includes a first ceiling portion 26A that is the front portion of the ceiling portion 26 and two first connecting portions 27A that are front portions of the connecting portion 27. The second mountain-shaped portion 25B includes a second ceiling portion 26B that is the rear portion of the ceiling portion 26 and two second connecting portions 27B that are rear portions of the connecting portion 27.

[0032] [Base material, convex part] As shown in FIG. 7 , the busbar 20 is composed of a plurality of (eight in this embodiment) plate-shaped substrates 30 stacked in the vertical direction. As shown in FIG. 8 , each substrate 30 includes two plate portions 31 and an intermediate plate portion 32 connecting the two plate portions 31. In this embodiment, the intermediate plate portion 32 is a convex portion 35 that protrudes upward from the plate portion 31. The convex portion 35 includes a protruding plate portion 36 parallel to the plate portion 31 and two side plate portions 37 connecting the plate portion 31 and the protruding plate portion 36. More specifically, the left side plate portion 37 connects the right end of the left plate portion 31 to the left end of the protruding plate portion 36, and the right side plate portion 37 connects the left end of the right plate portion 31 to the right end of the protruding plate portion 36. The side plate portions 37 are disposed perpendicular to the plate portions 31. In a plan view, the plurality of substrates 30 are disposed to have substantially the same shape and size.

[0033] As shown in Fig. 8, the base material 30 has an elongated hole 34 that penetrates the intermediate plate portion 32 in the up-down direction. The elongated hole 34 is disposed at the center of the base material 30 in the front-to-rear direction. The elongated hole 34 is elongated in the left-to-right direction and has a predetermined dimension in the front-to-rear direction. The elongated holes 34 of the multiple base materials 30 are formed to have approximately the same shape and size as one another in a plan view.

[0034] The elongated hole 34 penetrates the protrusion 35 in the up-down direction. Specifically, the left-right dimension of the elongated hole 34 is smaller than the left-right dimension of the protrusion 35, and the right and left ends of the elongated hole 34 are located closer to the protrusion 35 of the plate portion 31. In other words, the protrusion 35 is divided in the front-rear direction by the elongated hole 34.

[0035] Busbar 20 is manufactured by stacking multiple base materials 30 in the vertical direction and fixing plate portions 31 together by crimping or the like (see FIGS. 5 to 7). As shown in FIG. 6, connection portion 21, middle portion 22, angled portion 25, ceiling portion 26, and linking portion 27 of busbar 20 are respectively composed of plate portions 31, middle plate portions 32, convex portions 35, protruding plate portions 36, and side plate portions 37 of the stacked multiple base materials 30. As shown in FIG. 4, slits 24 of busbar 20 are formed by connecting elongated hole portions 34 of the multiple base materials 30 in the vertical direction.

[0036] [clearance] 6, a clearance CL is provided between adjacent protruding portions 35 of the busbar 20. More specifically, a clearance CL1 in the up-down direction is provided between adjacent protruding plate portions 36. A clearance CL2 in the left-right direction is provided between adjacent side plate portions 37.

[0037] By providing the clearance CL in this manner, the protrusions 35 are less likely to interfere with each other, and each protrusion 35 can more easily deform independently. This facilitates deformation of the angled portions 25. Furthermore, since no frictional force or the like acts between the protrusions 35, resistance to deformation of the angled portions 25 is reduced. Therefore, the busbar 20 is more likely to deform in the front-rear direction than when there is no clearance CL between adjacent protrusions 35. Furthermore, by providing the clearance CL, it becomes easier to stack a plurality of base materials 30.

[0038] The bus bar 20 of this embodiment has the above-described configuration, and modifications of the bus bar 20 will be described below.

[0039] [Deformation of busbar in left-right and up-down directions] In this embodiment, the left-right direction is the direction in which multiple energy storage elements 11 are stacked (see FIGS. 1 and 2). The up-down direction is the direction in which electrode terminals 12A, 12B and electrode welds 23 of bus bar 20 face each other, and is the direction in which bus bar 20 is assembled to electrode terminals 12A, 12B. Therefore, in the left-right and up-down directions, tolerances due to expansion and contraction of energy storage elements 11, manufacturing tolerances of energy storage elements 11, and assembly tolerances between energy storage elements 11 and bus bar 20 occur, for example. Bus bar 20 has a mountain-shaped portion 25 formed in a substantially inverted U-shape when viewed from the front (see FIGS. 4 and 5). Mountain-shaped portion 25 is elastically deformable in the left-right and up-down directions. Therefore, bus bar 20 can deform in the left-right and up-down directions to absorb tolerances in the left-right and up-down directions.

[0040] [Busbar deformation in the front-to-rear direction] In this embodiment, the front-rear direction is a direction perpendicular to both the stacking direction of the energy storage elements 11 and the direction in which the bus bar 20 is attached to the electrode terminals 12A, 12B (see FIGS. 1 and 2). Depending on the location of the energy storage module 10 and the type of spacers disposed between the energy storage elements 11, horizontally adjacent energy storage elements 11 may be misaligned with each other in the front-rear direction. For example, as shown in FIG. 9, if the right connection portion 21 is misaligned forward by dX relative to the left connection portion 21, the angled portion 25 disposed between the left and right connection portions 21 will be significantly deformed. Note that in FIG. 9, the energy storage elements 11 are not shown, and the amount of misalignment dX and the degree of deformation of the bus bar 20 are exaggerated (the same applies to FIG. 10).

[0041] The mountain-shaped portion 25 is divided into a first mountain-shaped portion 25A and a second mountain-shaped portion 25B by a slit 24 having a predetermined dimension in the width direction, so that the first mountain-shaped portion 25A and the second mountain-shaped portion 25B can deform independently without interfering with each other.

[0042] First, consider the deformation of the first mountain-shaped portion 25A. If the right-side connecting portion 21 is shifted forward by dX relative to the left-side connecting portion 21, the first ceiling portion 26A rotates primarily counterclockwise, and the first linking portion 27A deforms by twisting primarily counterclockwise. This causes stress to concentrate around the front and rear ends of the first linking portion 27A, where deformation is particularly large. As with the first mountain-shaped portion 25A, stress is also concentrated around the front and rear ends of the second connecting portion 27B in the second mountain-shaped portion 25B.

[0043] Next, a modification of busbar 720 that does not have slits 24, unlike the present embodiment, will be described with reference to Fig. 10. Except for the absence of slits 24, busbar 720 is configured in the same manner as busbar 20 of the present embodiment. In busbar 720, the same components as busbar 20 will be assigned the same reference numerals as those in busbar 20.

[0044] The busbar 720 includes two connection portions 21 and a mountain-shaped portion 725 that connects the two connection portions 21. An electrode weld portion 23 is provided on the underside of the connection portion 21. The mountain-shaped portion 725 includes a ceiling portion 726 that is parallel to the connection portions 21 and two connecting portions 727 that connect the ceiling portion 726 and the connection portions 21. If the right-side connection portion 21 is shifted forward by an amount dX relative to the left-side connection portion 21, the ceiling portion 726 rotates primarily counterclockwise, and the connecting portion 727 deforms so as to be twisted primarily counterclockwise. This causes stress to concentrate around the front and rear ends of the connecting portion 727.

[0045] Here, the deformation of busbar 20 and busbar 720 will be compared (see FIGS. 9 and 10). In busbar 20, stress is concentrated around the front and rear ends of first connecting portion 27A and around the front and rear ends of second connecting portion 27B. On the other hand, in busbar 720, stress is concentrated around the front and rear ends of connecting portion 727. Therefore, in busbar 20, stress can be more dispersed than in busbar 720.

[0046] 9 and 10, if the torsional angle of torsional deformation is the same, the front and rear ends of first connecting portion 27A and second connecting portion 27B will deform less than the front and rear ends of connecting portion 727, and the reaction force associated with torsional deformation will be smaller. Therefore, first connecting portion 27A and second connecting portion 27B are more susceptible to torsional deformation than connecting portion 727.

[0047] As described above, the slits 24 provided in the bus bar 20 can reduce stress applied to the electrode welds 23 when the left and right connection portions 21 are misaligned in the front-to-rear direction. This can prevent damage to the welded portions between the electrode welds 23 and the electrode terminals 12A, 12B, making it easier to maintain the reliability of the electrical connection between the bus bar 20 and the electrode terminals 12A, 12B.

[0048] [Effects of the First Embodiment] According to the first embodiment, the following actions and effects are achieved. The busbar 20 of embodiment 1 is a plate-shaped busbar 20 that connects multiple storage elements 11, and includes multiple connection portions 21 that are connected to the electrode terminals 12A, 12B of the multiple storage elements 11, and one or more intermediate portions 22 that connect adjacent connection portions 21. The connection portions 21 are arranged opposite the electrode terminals 12A, 12B, and include electrode welds 23 that are welded to the electrode terminals 12A, 12B. One or more slits 24 are provided in the intermediate portions 22, and the slits 24 are elongated in the arrangement direction (left-right direction) in which the connection portions 21 are arranged, and have a predetermined dimension in the width direction (front-back direction) that is perpendicular to both the arrangement direction and the opposing direction (up-down direction) in which the electrode welds 23 and the electrode terminals 12A, 12B oppose each other.

[0049] With this configuration, slits 24 make bus bar 20 more likely to deform in the width direction. Therefore, if energy storage elements 11 are misaligned in the width direction, stress applied to electrode welds 23 welded to electrode terminals 12A, 12B can be reduced. This makes it less likely that the electrical connection between bus bar 20 and electrode terminals 12A, 12B will be impaired.

[0050] In the first embodiment, the intermediate portion 22 is formed as a mountain-shaped portion 25 that protrudes from the connecting portion 21 in a direction away from the electrode terminals 12A and 12B.

[0051] According to this configuration, the provision of angled portions 25 can absorb tolerances in the arrangement direction. In addition, since the length of busbar 20 arranged between adjacent connection portions 21 increases, busbar 20 becomes more susceptible to deformation in the width direction.

[0052] The bus bar 20 according to the first embodiment is configured to include a plurality of plate-shaped base materials 30 stacked in an opposing direction.

[0053] With this configuration, the volume of bus bar 20 can be easily increased, and therefore heat generation by bus bar 20 can be suppressed even when energy storage elements 11 are at high voltage.

[0054] In the first embodiment, each base material 30 has a protrusion 35 that constitutes the mountain-shaped portion 25, and a clearance CL is provided between adjacent protrusions 35.

[0055] According to this configuration, clearance CL is provided between adjacent protrusions 35, and therefore each protrusion 35 is likely to deform independently, which makes bus bar 20 more likely to deform in the width direction.

[0056] The energy storage module 10 according to the first embodiment includes a plurality of energy storage elements 11 and a bus bar 20 connected to electrode terminals 12A, 12B of the plurality of energy storage elements 11.

[0057] With this configuration, it is possible to provide an electricity storage module 10 in which the electrical connection between the bus bar 20 and the electrode terminals 12A, 12B is less likely to be impaired.

[0058] <Embodiment 2> A second embodiment of the present disclosure will be described with reference to Figures 11 and 12. A busbar 120 according to the second embodiment has the same configuration as the busbar 20 according to the first embodiment, except that it has a plurality of slits 124. Hereinafter, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and a description of the same configurations, functions, and effects as those in the first embodiment will be omitted.

[0059] 11 and 12, the bus bar 120 has a plurality of slits 124 (three in this embodiment) that penetrate the middle portion 22 in the up-down direction. The three slits 124 are aligned in the front-rear direction in the middle portion 22. By providing the three slits 124, the mountain-shaped portion 125 of the bus bar 120 is divided, from the front side, into a first mountain-shaped portion 125A, a second mountain-shaped portion 125B, a third mountain-shaped portion 125C, and a fourth mountain-shaped portion 125D.

[0060] The first mountain-shaped portion 125A, the second mountain-shaped portion 125B, the third mountain-shaped portion 125C, and the fourth mountain-shaped portion 125D are shorter in the front-rear direction than the first mountain-shaped portion 25A and the second mountain-shaped portion 25B of embodiment 1. Therefore, as described above regarding the deformation of the bus bar 20 in the front-rear direction, when the left and right connection portions 21 are misaligned in the front-rear direction, these mountain-shaped portions 125A to 125D are less likely to be subjected to excessive stress and are more likely to deform than the first mountain-shaped portion 25A and the second mountain-shaped portion 25B.

[0061] [Effects of Embodiment 2] According to the second embodiment, the following actions and effects are achieved. In the second embodiment, a plurality of slits 124 are provided per intermediate portion 22 and are aligned in the width direction.

[0062] With this configuration, the number of slits 124 increases, making bus bar 120 more likely to deform in the width direction.

[0063] <Embodiment 3> A third embodiment of the present disclosure will be described with reference to Fig. 13. A busbar 220 according to the third embodiment has the same configuration as the busbar 20 according to the first embodiment, except for a connecting portion 227. Hereinafter, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and a description of the same configurations, functions, and effects as those in the first embodiment will be omitted.

[0064] In the angled portion 225 of the busbar 220, the coupling portion 227 forms an acute angle with the ceiling portion 26 and the connection portion 21 and is not disposed perpendicularly. Specifically, the left coupling portion 227 is positioned further left as it moves upward. The right coupling portion 227 is positioned further right as it moves upward. In other words, the coupling portion 227 protrudes in the arrangement direction (left-right direction) from the ceiling portion 26 toward the connection portion 21 as it moves from the connection portion 21 side toward the ceiling portion 26 side.

[0065] Because the connecting portion 227 of the busbar 220 protrudes toward the connecting portion 21, the length of the busbar 220 included in the angled portion 225 can be made longer than in the first embodiment, in which the connecting portion 27, the ceiling portion 26, and the connecting portion 21 are arranged perpendicularly (see FIG. 5). In other words, the extra length of the busbar 220 that can deform when the busbar 220 deforms in the front-rear direction can be set longer. Therefore, when the left and right connecting portions 21 are misaligned in the front-rear direction, the busbar 220 is more likely to deform than the busbar 20.

[0066] [Effects of the Third Embodiment] According to the third embodiment, the following actions and effects are achieved. In embodiment 3, the mountain-shaped portion 225 comprises a ceiling portion 26 parallel to the connection portion 21, and a connecting portion 227 connecting the ceiling portion 26 and the connection portion 21, and the connecting portion 227 protrudes in the direction from the ceiling portion 26 toward the connection portion 21 in the arrangement direction as it moves from the connection portion 21 side toward the ceiling portion 26 side.

[0067] With this configuration, since the connecting portion 227 protrudes toward the connection portion 21, the length of the bus bar 220 arranged between adjacent connection portions 21 increases, making the bus bar 220 more likely to deform in the width direction.

[0068] <Embodiment 4> A fourth embodiment of the present disclosure will be described with reference to Fig. 14. A busbar 320 according to the fourth embodiment does not include the angled portion 25 of the first embodiment. Hereinafter, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and descriptions of the same configurations, functions, and effects as those in the first embodiment will be omitted.

[0069] Busbar 320 is flat and includes two connection portions 21 and one intermediate portion 322 connecting the two connection portions 21. That is, in busbar 320, connection portions 21 and intermediate portion 322 are configured to be flush with each other. Busbar 320 has slits 24 that pass through intermediate portion 322 in the up-down direction.

[0070] When the left and right connecting portions 21 are misaligned in the front-to-rear direction, the middle portion 322 is primarily deformed. The middle portion 322 is not elastically deformable, and its deformation mode is different from that of the mountain-shaped portion 25 of the first embodiment. However, the provision of the slits 24 is expected to have the effect of making the middle portion 322 more easily deformable, as in the first embodiment. In other words, by dividing the middle portion 322 by the slits 24, it is thought that the stress acting on the middle portion 322 can be dispersed and the reaction force due to the deformation of the middle portion 322 can be reduced compared to when the slits 24 are not provided.

[0071] <Embodiment 5> A fifth embodiment of the present disclosure will be described with reference to Fig. 15. A busbar 420 according to the fifth embodiment is configured similarly to the busbar 20 of the first embodiment, and further includes a positioning hole 428 that penetrates the connection portion 21. Although not shown, the plurality of substrates 30 that make up the busbar 420 also include circular through-holes that form the positioning holes 428. Hereinafter, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and descriptions of the same configurations, functions, and effects as those in the first embodiment will be omitted.

[0072] Positioning hole 428 is provided in approximately the center of connecting portion 21. Although not shown, energy storage element 11 may be provided with cylindrical protrusions (not shown) that protrude upward from the top surfaces of electrode terminals 12A and 12B. In such cases, bus bar 420 can be positioned relative to electrode terminals 12A and 12B by engaging the inner walls of positioning hole 428 with the protrusions.

[0073] Furthermore, when stacking multiple base materials 30 in the manufacturing process of bus bar 420, by inserting pins or the like into the through holes of the multiple base materials 30, the multiple base materials 30 can be easily positioned relative to one another.

[0074] <Other embodiments> (1) In the first embodiment, the bus bar 20 has two connection portions 21 and one intermediate portion 22, and is configured to connect the electrode terminals 12A, 12B of adjacent energy storage elements 11, but this is not limited thereto. The bus bar may have three or more connection portions and one intermediate portion less than the connection portions, and may connect the same number of energy storage elements as the number of connection portions. Furthermore, the polarities of the multiple electrode terminals connected to the bus bar may be the same or some may be different. (2) In the first embodiment, the bus bar 20 is formed by stacking a plurality of base materials 30, but this is not limitative, and the bus bar may be formed by a single base material. (3) In the first embodiment, a clearance CL is provided between adjacent protrusions 35, but this is not limiting, and adjacent protrusions may be stacked without any gaps.

[0075] (4) In the first embodiment, the mountain-shaped portion 25 has an angular inverted U-shape when viewed from the front. However, this is not limited to this, and the mountain-shaped portion may have a rounded inverted U-shape when viewed from the front. (5) In the first embodiment, the busbar 20 is formed by stacking and fixing together a plurality of base materials 30 that have been preformed by punching and bending metal sheets. However, this is not limited to this, and the order of the steps of stacking, fixing, and forming the plurality of base materials can be changed as desired. For example, the plurality of base materials may be preformed by punching metal sheets, stacked, fixed, and then bent. Alternatively, the preformed plurality of base materials may be folded, stacked, welded, and then trimmed. [Explanation of symbols]

[0076] 10: Energy storage module 11: Energy storage element 12A,12B: Electrode terminal 20: Busbar 21: Connection 22: Middle section 23: Electrode welding part 24: Slit 25: Yamagata 25A: First mountain section 25B: Second mountain section 26: Ceiling 26A: 1st ceiling section 26B: Second ceiling section 27: Connection part 27A: 1st connection part 27B: 2nd connection part 30: Base material 31: Board part 32: Intermediate plate 34: Long hole part 35: Convex 36: Projecting plate part 37: Side plate part 120: Busbar 124: Slit 125: Yamagata 125A: First mountain section 125B: Second mountain section 125C: Third mountain section 125D: 4th mountain section 220: Busbar 225: Yamagata 227: Connecting part 320: Busbar 322: Middle section 420: Busbar 428: Positioning hole 720: Busbar 725: Yamagata 726: Ceiling 727: Connecting part CL: Clearance CL1: Vertical clearance CL2: Lateral clearance LL: Dimension of the long side of the slit LW: Dimension in the width direction of the slit dX: The amount of misalignment in the front-to-back direction between the left and right joints

Claims

1. A plate-shaped bus bar that connects a plurality of energy storage elements, a plurality of connection portions connected to the electrode terminals of the plurality of energy storage elements; and one or more intermediate portions connecting adjacent connection portions, the connection portion is disposed to face the electrode terminal and includes an electrode welding portion welded to the electrode terminal, The intermediate portion is provided with one or more slits; the slit has a shape elongated in a direction in which the connection portions are arranged, and has a predetermined dimension in a width direction perpendicular to both the direction in which the connection portions are arranged and a direction in which the electrode welding portion and the electrode terminal face each other; the intermediate portion is a mountain-shaped portion that protrudes from the connection portion in a direction away from the electrode terminal, the bus bar is configured to include a plurality of plate-shaped base materials stacked in the opposing direction, Each of the base materials has a convex portion that constitutes the mountain-shaped portion, the protrusion has a vertical plane extending in the opposing direction and a horizontal plane extending in the arrangement direction, A clearance is provided between adjacent protrusions, The clearances include a first clearance in the opposing direction provided between adjacent horizontal planes, and a second clearance in the arrangement direction provided between adjacent vertical planes.

2. The busbar according to claim 1 , wherein a plurality of the slits are provided in each of the intermediate portions and are aligned in the width direction.

3. the mountain-shaped portion includes a ceiling portion parallel to the connection portion and a connecting portion connecting the ceiling portion and the connection portion, The bus bar according to claim 1 or 2, wherein the coupling portion protrudes in a direction from the ceiling portion toward the connection portion in the arrangement direction as the coupling portion moves from the connection portion toward the ceiling portion.

4. An energy storage module comprising: a plurality of energy storage elements; and the bus bar according to claim 1 or 2 connected to electrode terminals of the plurality of energy storage elements.

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