Energy storage module

Abstract

To provide a power storage module capable of improving positioning accuracy between an external terminal and a bus bar with a simple configuration.SOLUTION: A power storage module 100 includes a first storage cell 21 and a second storage cell 22 having external terminals, a bus bar 30 connecting the external terminal 24 of the first storage cell 21 and the external terminal 23 of the second storage cell 22, the external terminals 24 and 23 are provided with recesses 245 and 235, the external terminals 24 and 23 include inner wall portions 245a and 235a that define the recesses 245 and 235, and outer wall portions 246 and 236 that define the peripheral edges of the external terminals 24 and 23, the bus bar 30 includes engaging portions 313 and 323 that engage with the external terminals, and the engaging portions 313 and 323 include first contact portions 311 and 321 that contact the inner wall portions 245a and 235a, and second contact portions 312 and 322 that contact the outer wall portions 246 and 236.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an energy storage module mounted on a vehicle. [Background technology]

[0002] BACKGROUND ART Conventionally, a power storage module has been developed that includes a plurality of power storage cells each having an external terminal, and a bus bar that connects the external terminals of adjacent power storage cells to each other.

[0003] In JP 2021-068625 A (Patent Document 1), a bus bar is provided with a first engagement portion that hangs down from one end of the bus bar and a second engagement portion that hangs down from the other end of the bus bar. Furthermore, in a first battery and a second battery that are adjacent to each other, a first recess that engages with the first engagement portion is provided in the battery case of the first battery, and a second recess that engages with the second engagement portion is provided in the battery case of the second battery.

[0004] By engaging the first engaging portion with the first recess and the second engaging portion with the second recess, the first battery and the second battery are held between the first engaging portion and the second engaging portion, which makes it possible to prevent the welded portion between the bus bar and the external terminal from weakening even when vibration is transmitted from the outside to the energy storage module. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-068625 Summary of the Invention [Problem to be solved by the invention]

[0006] In the configuration disclosed in Patent Document 1, the external terminal of the energy storage cell is formed by a bolt and includes a protruding portion that protrudes upward, and with the protruding portion passing through a through hole formed in the flat plate portion of the bus bar, the first engaging portion and the second engaging portion engage with the first recessed portion and the second recessed portion. In this case, the bus bar and the external terminal are positioned by passing the protruding portion of the external terminal through the through hole of the bus bar.

[0007] On the other hand, in some cases, the external terminal is configured so that a recess is provided on a substantially flat upper end surface without providing a protrusion, and in such cases, the protrusion cannot be inserted into the through-hole of the bus bar, making it difficult to accurately position the bus bar relative to the external terminal.

[0008] Furthermore, in the configuration of Patent Document 1, it is necessary to provide a first recess or a second recess in the battery case in order to engage the first engaging portion and the second engaging portion, which makes the configuration complicated.

[0009] The present disclosure has been made in consideration of the above-described problems, and an object of the present disclosure is to provide an energy storage module that has a simple configuration and can improve the positioning accuracy between external terminals and bus bars. [Means for solving the problem]

[0010] The energy storage module according to the present disclosure includes a first energy storage cell and a second energy storage cell, each having an external terminal, and a bus bar connecting the external terminal of the first energy storage cell and the external terminal of the second energy storage cell. The external terminal has a recess. The external terminal includes an inner wall portion that defines the recess and an outer wall portion that defines a periphery of the external terminal. The bus bar includes an engaging portion that engages with the external terminal. The engaging portion has a first abutting portion that abuts against the inner wall portion and a second abutting portion that abuts against the outer wall portion.

[0011] According to the above configuration, in an external terminal having a recess, the first engagement portion of the bus bar is engaged with the inner wall portion of the external terminal that defines the recess, and the second engagement portion is engaged with the outer wall portion of the external terminal, thereby improving the positioning accuracy of the external terminal and the bus bar with a simple configuration.

[0012] In the energy storage module according to the present disclosure, the first abutting portion may have a first tip abutting the inner wall portion, and may have a shape that moves away from the inner wall portion and then approaches the inner wall portion again as it moves from the first tip toward an opening end of the recess. Also, the second abutting portion may have a second tip abutting the outer wall portion, and may have a shape that moves away from the outer wall portion and then approaches the outer wall portion again as it moves from the second tip toward the opening end.

[0013] According to the above configuration, since the first contact portion and the second contact portion have the above-described shapes, the external terminal can be gripped by the first contact portion and the second contact portion.

[0014] In the energy storage module based on the present disclosure, the first abutment portion may be provided so as to fit along the inner wall portion, and the second abutment portion may be provided so as to fit along the outer wall portion.

[0015] According to the above configuration, the configurations of the first contact portion and the second contact portion can be simplified.

[0016] In the energy storage module according to the present disclosure, the bus bar may have a cover portion that fits into the recess and covers the recess.

[0017] According to the above configuration, the recessed portion is provided in the cover portion, which prevents liquid such as water from adhering to the recessed portion, thereby making it possible to prevent corrosion of the external terminals.

[0018] In the energy storage module according to the present disclosure, one of the external terminals of the first energy storage cell and the second energy storage cell may have a first metal portion and a second metal portion formed from a metal different from that of the first metal portion, and the second metal portion may be joined to an upper portion of the first metal portion by dissimilar metal bonding. In this case, the second metal portion may be provided with the recess.

[0019] According to the above configuration, the bus bar is accurately positioned relative to the external terminal, which reduces heat input to the dissimilar metal joint when welding the bus bar to the external terminal, thereby suppressing the formation of intermetallic compounds and reducing the strength of the dissimilar metal joint. [Effects of the Invention]

[0020] According to the present disclosure, it is possible to provide an energy storage module that has a simple configuration and can improve the positioning accuracy between external terminals and bus bars. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a schematic plan view of an electricity storage module according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view taken along line II-II shown in FIG. [Figure 3] 3 is a schematic plan view showing the configuration around an external terminal of the energy storage module according to the first embodiment. FIG. [Figure 4] 10 is a schematic cross-sectional view showing an external terminal and a bus bar of an energy storage module according to a comparative example. [Figure 5] FIG. 10 is a schematic plan view showing the configuration around an external terminal of an electricity storage module according to a comparative example. [Figure 6] 10A and 10B are views showing how a bus bar is welded to an external terminal in an energy storage module according to a first modified example. [Figure 7] 10 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an energy storage module according to a second modification. FIG. [Figure 8]10 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an energy storage module according to a third modification. FIG. [Figure 9] 10 is a schematic cross-sectional view showing how a bus bar according to a third modified example prevents liquid from entering a recessed portion. FIG. [Figure 10] 10 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an electricity storage module according to a fourth modification. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the embodiments described below, the same or common parts are denoted by the same reference numerals in the drawings, and the description thereof will not be repeated.

[0023] (Embodiment 1) Fig. 1 is a schematic plan view of the energy storage module according to embodiment 1. Fig. 2 is a schematic cross-sectional view taken along line II-II shown in Fig. 1. The energy storage module 100 according to embodiment 1 will be described with reference to Figs. 1 and 2.

[0024] The power storage module 100 according to the embodiment is mounted on a hybrid vehicle that can run using at least one of the power of a motor and an engine, or an electric vehicle that runs on driving force obtained from electric energy. The power storage module 100 may be mounted below a floor panel of the vehicle, or may be disposed between the floor panel and a seat.

[0025] As shown in FIG. 1, the energy storage module 100 according to the first embodiment includes a plurality of energy storage cells 20, a plurality of bus bars 30, and a pair of end plates 11.

[0026] The plurality of energy storage cells 20 are arranged side by side in a predetermined arrangement direction. A pair of end plates 11 are arranged at both ends in the arrangement direction. The plurality of energy storage cells 20 are sandwiched between the pair of end plates 11 and restrained by restraining members (not shown).

[0027] The plurality of storage cells 20 are, for example, secondary batteries such as nickel-metal hydride batteries or lithium-ion batteries. The single cells have, for example, a rectangular shape. The secondary batteries may use a liquid electrolyte or a solid electrolyte. The storage cells 20 may also be unit capacitors configured to be capable of storing electricity.

[0028] The energy storage cell 20 includes a housing 210 and external terminals 23 and 24. The housing 210 accommodates a battery element 27 and an electrolyte 28. The housing 210 has a main body 211 provided with an opening that opens upward, and a sealing body 212 that seals the opening.

[0029] The external terminals 23 and 24 are provided on the upper surface 210a of the housing 210. The external terminals 23 are arranged on one side in the width direction of the energy storage cells 20 that is perpendicular to the arrangement direction, and the external terminals 24 are arranged on the other side in the width direction.

[0030] The external terminal 23 is, for example, a positive electrode terminal, and is connected to the positive electrode of the battery element 27 by a current collecting member (not shown). The external terminal 23 is insulated from the housing 210 (more specifically, the sealing body 212) by an insulator 25. The external terminal 23 is formed, for example, from an aluminum alloy.

[0031] The external terminal 23 has a recess 235. The external terminal 23 has an upper end surface 23a. The recess 235 is provided in approximately the center of the upper end surface 23a. The external terminal 23 has an inner wall portion 235a that defines the recess 235, and an outer wall portion 236 that defines the periphery of the external terminal 23.

[0032] The external terminal 24 is, for example, a negative electrode terminal, and is connected to the negative electrode of the battery element 27 by a current collecting member (not shown). The external terminal 23 is insulated from the housing 210 (more specifically, the sealing body 212) by an insulator 26.

[0033] The external terminal 24 has a recess 245. The external terminal 24 has an upper end surface 24a. The recess 245 is provided in approximately the center of the upper end surface 24a. The external terminal 24 has an inner wall portion 245a that defines the recess 245, and an outer wall portion 246 that defines the periphery of the external terminal 24.

[0034] The external terminal 24 has a first metal portion 241 and a second metal portion 242 formed from a metal different from that of the first metal portion 241. The first metal portion 241 constitutes the lower portion of the external terminal 24, and the second metal portion 242 constitutes the upper portion of the external terminal 24.

[0035] The first metal portion 241 is formed of, for example, a copper alloy, and the second metal portion 242 is formed of, for example, an aluminum alloy. The second metal portion 242 is dissimilarly metal-joined to the upper portion of the first metal portion 241. By dissimilar metal joining, an effective connection portion 243 where the first metal portion 241 and the second metal portion 242 are joined to each other is formed at the joining surface between the dissimilar metals.

[0036] The second metal portion 242 has an upper surface. The upper surface of the second metal portion 242 constitutes the upper end surface 24a. The second metal portion 242 is provided with the recess 245.

[0037] The dissimilar metals are joined by, for example, friction stir spot welding, ultrasonic welding, or resistance welding. Various welding devices are used for the joining, and recesses 245 are formed at the contact points between the welding device and second metal part 242.

[0038] The plurality of storage cells 20 include a first storage cell 21 and a second storage cell 22 arranged adjacent to each other. The first storage cell 21 and the second storage cell 22 have the same structure as the storage cell 20. The first storage cell 21 and the second storage cell 22 are arranged such that the external terminals 23 and the external terminals 24 are alternately arranged along the arrangement direction.

[0039] The bus bar 30 connects the external terminals of the first storage cell 21 and the second storage cell 22 that are adjacent to each other. More specifically, the bus bar 30 connects the external terminal 24 of the first storage cell 21 and the external terminal 23 of the second storage cell 22 on one side in the width direction. The bus bar 30 also connects the external terminal 23 of the first storage cell 21 and the external terminal 24 of the second storage cell 22 on the other side in the width direction. This allows the multiple storage cells 20 to be connected in series.

[0040] The bus bar 30 has a first portion 31, a second portion 32, and a third portion 33. The first portion 31 is connected to the external terminal 24. The second portion 32 is connected to the external terminal 23. The third portion 33 connects the first portion 31 and the second portion 32. The third portion 33 has a plate-like shape.

[0041] The first portion 31 has a plate-shaped portion 310 and a first engagement portion 313. The plate-shaped portion 310 is placed on the upper end surface 24a of the external terminal 24. The plate-shaped portion 310 has a welded portion 36 welded to the external terminal 24. An opening is provided in the plate-shaped portion 310 so as to face the recess 245, and the plate-shaped portion 310 has a generally frame-like shape. As a result, the plate-shaped portion 310 has an inner end and an outer end.

[0042] The first engagement portion 313 has a first contact portion 311 and a second contact portion 312. The first contact portion 311 is provided on the inner end portion of the plate-shaped portion 310. The first contact portion 311 comes into contact with the inner wall portion 245a of the external terminal 24.

[0043] The first contact portion 311 has a substantially C-shape. Specifically, the first contact portion 311 has a tip portion (first tip portion) that abuts against the inner wall portion 245a, and has a shape that moves away from the tip portion toward the open end of the recess 245 and then approaches the inner wall portion 245a again. A base portion of the first contact portion 311 is connected to the plate-shaped portion 310.

[0044] The second contact portion 312 is provided on the outer end portion of the plate-shaped portion 310. The second contact portion 312 comes into contact with the outer wall portion 246 of the external terminal .

[0045] The second contact portion 312 has a substantially C-shape. Specifically, it has a tip portion (second tip portion) that abuts against the outer wall portion 246, and as it moves from the tip portion toward the open end of the recess 245, it has a shape that moves away from the outer wall portion 246 and then approaches the outer wall portion 246 again. A base portion of the second contact portion 312 is connected to the plate-shaped portion 310.

[0046] The first contact portion 311 and the second contact portion 312 have the shapes described above, so that the first engagement portion 313 can grip the external terminal 24 .

[0047] The second portion 32 has a plate-shaped portion 320 and a second engagement portion 323. The plate-shaped portion 320 is placed on the upper end surface 23a of the external terminal 23. The plate-shaped portion 320 has a welded portion 36 welded to the external terminal 23. An opening is provided in the plate-shaped portion 320 so as to face the recess 235, and the plate-shaped portion 320 has a substantially frame-like shape. As a result, the plate-shaped portion 320 has an inner end and an outer end.

[0048] The second engagement portion 323 has a first contact portion 321 and a second contact portion 322. The first contact portion 321 is provided on the inner end portion of the plate-shaped portion 320. The first contact portion 321 comes into contact with the inner wall portion 235a of the external terminal .

[0049] The first contact portion 321 has a substantially C-shape. Specifically, the first contact portion 321 has a tip portion (second tip portion) that abuts against the inner wall portion 235a, and has a shape that moves away from the tip portion toward the open end of the recess 235 and then approaches the inner wall portion 235a again. A base portion of the second contact portion 322 is connected to the plate-shaped portion 320.

[0050] The second contact portion 322 is provided on the outer end portion of the plate-shaped portion 310. The second contact portion 322 comes into contact with the outer wall portion 236 of the external terminal .

[0051] The second contact portion 322 has a substantially C-shape. Specifically, it has a tip portion (second tip portion) that abuts against the outer wall portion 236, and as it moves from the tip portion toward the open end of the recess 235, it has a shape that moves away from the outer wall portion 236 and then approaches the outer wall portion 236 again. A base portion of the second contact portion 322 is connected to the plate-shaped portion 320.

[0052] The first contact portion 321 and the second contact portion 322 have the shapes described above, so that the second engagement portion 323 can grip the external terminal 23.

[0053] 3 is a schematic plan view showing the configuration of the periphery of the external terminals of the energy storage module according to Embodiment 1. As shown in FIG.

[0054] The FPC 50 is disposed adjacent to the bus bar 30 on one side of the storage cells 20 in the width direction, and is provided to extend along the arrangement direction of the storage cells 20. The FPC 50 includes a wiring portion 51 connected to the bus bar 30.

[0055] Here, the bus bar 30 is assembled to the external terminals 24, 23 by bringing the first contact portions 311, 321 into contact with the inner wall portions 245a, 235a that define the recesses 245, 235, and bringing the second contact portions 312, 322 into contact with the outer wall portions 246, 236. Therefore, with a simple configuration, it is possible to improve the positioning accuracy between the external terminals 24, 23 and the bus bar 30.

[0056] Furthermore, in the assembled state, even if a reaction force from the FPC 50 acts on the busbar 30 as shown by the arrow AR1 in Figure 3, the first engagement portion 313 and the second engagement portion 323 engage with the external terminals 24 and 23, thereby preventing the external terminals 24 and 23 from shifting from the busbar 30.

[0057] This makes it possible to ensure a large overlapping area between the upper end surface 24a of the external terminal 24 and the plate-shaped portion 310, and between the upper end surface 23a of the external terminal 23 and the plate-shaped portion 320. This makes it possible to ensure a large welding area R1, indicated by the dashed dotted line in FIG.

[0058] Furthermore, by accurately positioning the external terminals 24, 23 and the bus bar 30, it is possible to prevent deviation of the laser irradiation position during welding. This prevents the recesses 245, 235 from being irradiated with the laser, and in particular, it is possible to prevent heat input from the laser to the effective connection portion 243 of the dissimilar metal joint. This prevents the generation of an intermetallic compound in the effective connection portion 243 and prevents a decrease in joint strength.

[0059] Generally, when a laser is irradiated onto the recesses 245, 235, sparks are generated, fumes fly, and foreign matter may adhere to the recesses 245, 235. As described above, by suppressing deviation in the laser irradiation position, it is possible to suppress the adhesion of such foreign matter.

[0060] Furthermore, even if a load is transmitted to the busbar 30 due to vehicle vibration or impact, the first engaging portion 313 and the second engaging portion 323 engage with the external terminals 24 and 23, thereby reducing the load on the welded portion 36. This also improves the fatigue strength of the busbar 30.

[0061] Fig. 4 is a schematic cross-sectional view showing the external terminals and bus bars of a power storage module according to a comparative example. Fig. 5 is a schematic plan view showing the configuration around the external terminals of the power storage module according to the comparative example. The power storage module 100X according to the comparative example will be described with reference to Figs. 4 and 5.

[0062] 4 and 5, the energy storage module 100X according to the comparative example differs from the energy storage module 100 according to embodiment 1 in the shape of the busbar 30X. The other configurations are substantially the same.

[0063] Compared to the busbar 30 according to the first embodiment, the busbar 30X does not have the first engagement portion 313 and the second engagement portion 323. That is, the busbar 30X is formed in a flat plate shape as a whole. The first portion 31 is formed by a plate-like portion 310 having an opening 31 a, and the second portion 32 is formed by a plate-like portion 320 having an opening 32 a.

[0064] When welding the bus bar 30X to the external terminals 24, 23, the bus bar 30X is placed on the upper end surfaces 24a, 23a. At this time, if a reaction force from the FPC 50 acts on the bus bar 30X, as indicated by the arrow AR1 in FIG. 5 , the absence of the first engagement portion 313 and the second engagement portion 323 causes the bus bar 30X to shift position. This reduces the overlapping area between the plate-shaped portions 310, 320 and the upper end surfaces 24a, 23a. As a result, the welding area R2 indicated by the dashed-dotted line in FIG. 5 also becomes smaller. Furthermore, the misalignment of the bus bar 30X also causes the laser irradiation position to shift, potentially resulting in heat being input to the effective connection portion 243.

[0065] (First Modification) FIG. 6 is a diagram showing how the bus bars are welded to the external terminals in the energy storage module according to the first modification.

[0066] In the above-described first embodiment, an example is given in which, before welding the bus bar 30, the first abutment portion 311 and the second abutment portion 312 abut against the inner wall portion 245a and the outer wall portion 246, and the first abutment portion 321 and the second abutment portion 322 abut against the inner wall portion 235a and the outer wall portion 236. However, these first abutment portions 311, 321 and second abutment portions 312, 322 may abut against the inner wall portions 245a, 235a and the outer wall portions 246, 236 after welding the bus bar 30.

[0067] In this case, before welding the bus bar 30, as shown by the dashed lines in Figure 6, the first abutment portions 311, 321 and the second abutment portions 312, 322 are spaced a predetermined distance from the inner wall portions 245a, 235a and the outer wall portions 246, 236 in anticipation of thermal contraction of the bus bar 30 by the laser.

[0068] Even when configured in this manner, after welding, the first abutment portion 311 and the second abutment portion 312 abut against the inner wall portion 245a and the outer wall portion 246, and the first abutment portion 321 and the second abutment portion 322 abut against the inner wall portion 235a and the outer wall portion 236, so that the storage module of the first modified example achieves substantially the same effect as the storage module 100 of embodiment 1.

[0069] (Second Modification) 7 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an energy storage module according to Modification 2. Referring to FIG. 7, an energy storage module 100A according to Modification 2 will be described.

[0070] 7, the energy storage module 100A according to the second modification is different from the energy storage module 100 according to the first embodiment in the shape of the busbar 30A. The other configurations are almost the same.

[0071] On the first portion 31A side, the first engagement portion 313 has a first contact portion 311A ​​and a second contact portion 312A. The first contact portion 311A ​​is provided so as to fit along the inner wall portion 245a of the external terminal 24. The second contact portion 312A is provided so as to fit along the outer wall portion 246 of the external terminal 24.

[0072] 7, for convenience, the first portion 31A side of the busbar 30A joined to the external terminal 24 is shown, but the configuration of the second portion side of the busbar 30A joined to the external terminal 23 is substantially the same as that of the first portion 31A side. Although not shown here, on the second portion side as well, the first abutment portion is provided so as to fit along the inner wall portion 235a of the external terminal 23, and the second abutment portion is provided so as to fit along the outer wall portion 236 of the external terminal 23.

[0073] Even when configured in this manner, the energy storage module 100A according to the second modification can achieve substantially the same effects as the energy storage module 100 according to embodiment 1. Furthermore, by forming the first abutment portion 311A ​​and the second abutment portion 312A in a linear shape, the configuration of the busbar 30A can be further simplified.

[0074] (Third Modification) 8 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an energy storage module according to Modification 3. A power storage module 100B according to Modification 3 will be described with reference to FIG.

[0075] 8, the energy storage module 100B according to the third modification is different from the energy storage module 100B according to the first embodiment in the shape of the busbar 30B. The other configurations are almost the same.

[0076] In the third modified example, the plate-shaped portion 310 is provided on the first portion 31B side with a protrusion 315 that fits into the recess 245. When the protrusion 315 is fitted into the recess 245, the protrusion 315 abuts against the inner wall 245a and functions as a first abutment of the first engagement portion 313. The protrusion 315 also fits into the recess 245 and functions as a cover that covers the recess 245. The second abutment 312B of the first engagement portion 313 is provided so as to fit along the outer wall 246 of the external terminal 24 located on the third portion 33 side.

[0077] 8 illustrates the first portion 31B of the busbar 30B joined to the external terminal 24 for convenience, but the configuration of the second portion of the busbar 30B joined to the external terminal 23 is substantially the same as that of the first portion 31B. Although not shown here, the second portion also has a protrusion on the plate-like portion 320 that fits into the recess 235. The second abutment portion of the second engagement portion is provided so as to fit along the outer wall 236 of the external terminal 23 located on the third portion 33 side.

[0078] FIG. 9 is a schematic cross-sectional view showing how the bus bar according to the third modification prevents liquid from entering the recessed portion.

[0079] 9, the recess 245 is covered by the protrusion 315 and is not exposed to the outside. This makes it possible to prevent liquid W such as water from adhering to the recess 245. This makes it possible to prevent corrosion of the external terminal 24.

[0080] Even when configured as described above, the power storage module 100B according to the third modification can achieve substantially the same effects as the power storage module 100 according to embodiment 1. In addition, as described above, corrosion of the external terminals can be suppressed.

[0081] (Fourth Modification) 10 is a schematic cross-sectional view showing an enlarged view of a part of a bus bar and its periphery provided in an energy storage module according to Modification 4. An energy storage module 100C according to Modification 4 will be described with reference to FIG.

[0082] 10, the energy storage module 100C according to the fourth modification is different from the energy storage module 100 according to the first embodiment in the shape of the busbar 30C. The other configurations are almost the same.

[0083] 10, similarly to the second modified example, the first contact portion 311A ​​of the first engagement portion 313 is provided so as to follow the inner wall portion 245a. The second contact portion 312A of the first engagement portion 313 is also provided so as to follow the outer wall portion 246. In this case, the second contact portion 312A is provided on the side where the third portion 33 is located.

[0084] Furthermore, in the fourth modification, busbar 30C has connecting portion 316 that connects first contact portions 311A ​​to each other. Connecting portion 316 is provided so as to cover the bottom portion of recess 245. In this manner, first contact portion 311A ​​and connecting portion 316 function as a covering portion that fits into recess 245 and covers recess 245.

[0085] 10 illustrates the first portion 31C of the busbar 30C joined to the external terminal 24 for convenience, but the configuration of the second portion of the busbar 30C joined to the external terminal 23 is substantially the same as that of the first portion 31C. Although not shown here, a connecting portion that connects the first contact portions is also provided on the second portion, and the first contact portion and the connecting portion function as the covering portion described above.

[0086] Even when configured in this manner, the energy storage module 100C according to the fourth modification example can achieve substantially the same effects as the energy storage module 100 according to embodiment 1. In addition, as described above, the provision of the cover portion can prevent the external terminals from corroding.

[0087] It should be noted that in the above-described first embodiment and the second to fourth modified examples, it was originally planned to appropriately combine the respective characteristic portions of each.

[0088] The embodiments and modifications disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims, and includes all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0089] 11 end plate, 20 energy storage cell, 21 first energy storage cell, 22 second energy storage cell, 23 external terminal, 23a upper end surface, 24 external terminal, 24a upper end surface, 25, 26 insulator, 27 battery element, 28 electrolyte, 30, 30A, 30B, 30C, 30X bus bar, 31, 31A, 31B, 31C first portion, 31a, 32a opening, 32 second portion, 33 third portion, 36 welded portion, 51 wiring portion, 100, 100A, 100B, 100C, 100X energy storage module, 210 housing, 210a upper surface, 211 main body portion, 212 sealing body, 235 recess, 235a inner wall portion, 236 outer wall portion, 241 first metal portion, 242 Second metal portion, 243 effective connection portion, 245 recessed portion, 245a inner wall portion, 246 outer wall portion, 310 plate-shaped portion, 311, 311A ​​first abutment portion, 312, 312A, 312B second abutment portion, 313 first engagement portion, 315 protrusion portion, 316 connection portion, 320 plate-shaped portion, 321 first abutment portion, 322 second abutment portion, 323 second engagement portion.

Claims

1. a first storage cell and a second storage cell each having an external terminal; a bus bar connecting the external terminal of the first storage cell and the external terminal of the second storage cell, The external terminal is provided with a recess, the external terminal includes an inner wall portion that defines the recess and an outer wall portion that defines a periphery of the external terminal; the bus bar includes an engaging portion that engages with the external terminal, the engaging portion has a first contact portion that contacts the inner wall portion and a second contact portion that contacts the outer wall portion, one of the external terminal of the first storage cell and the external terminal of the second storage cell has a first metal portion and a second metal portion formed from a metal different from that of the first metal portion; the second metal portion is joined to an upper portion of the first metal portion by dissimilar metal joining, The recess is provided in the second metal portion.

2. the first abutment portion has a first tip end portion that abuts against the inner wall portion, and has a shape that moves away from the inner wall portion and then approaches the inner wall portion again as it moves from the first tip end portion toward an opening end of the recess, 2. The energy storage module according to claim 1, wherein the second abutment portion has a second tip end that abuts against the outer wall portion, and has a shape that moves away from the outer wall portion and then approaches the outer wall portion again as it moves from the second tip end toward the opening end.

3. the first contact portion is provided along the inner wall portion, The energy storage module according to claim 1 , wherein the second contact portion is provided along the outer wall portion.

4. The energy storage module according to claim 1 , wherein the bus bar has a cover portion that fits into the recess and covers the recess.

5. A first storage cell and a second storage cell, each having an external terminal; a bus bar connecting the external terminal of the first storage cell and the external terminal of the second storage cell, The external terminal is provided with a recess, the external terminal includes an inner wall portion that defines the recess and an outer wall portion that defines a periphery of the external terminal; the bus bar includes an engaging portion that engages with the external terminal, the engaging portion has a first contact portion that contacts the inner wall portion and a second contact portion that contacts the outer wall portion, the first abutment portion has a first tip end portion that abuts against the inner wall portion, and has a shape that moves away from the inner wall portion and then approaches the inner wall portion again as it moves from the first tip end portion toward an opening end of the recess, the second abutment portion has a second tip portion that abuts against the outer wall portion, and has a shape that moves away from the outer wall portion and then approaches the outer wall portion again as it moves from the second tip portion toward the opening end.

Images