Energy storage device

Abstract

This method suppresses the increase in the number of components while preventing debris from coming into contact with the cell terminals. [Solution] In the energy storage device 10, the first cell terminal 112 faces the second battery module 200. The first restraining member 120 is provided on the first cell case 111 of each of the multiple first cells 110 so as to apply a restraining load to the multiple first cells 110 in a second direction. The second cell terminal 212 faces the first battery module 100. The second restraining member 220 is provided on the second cell case 211 of each of the multiple second cells 210 so as to apply a restraining load to the multiple second cells 210 in a second direction. The first restraining member 120 and the second restraining member 220 are connected to each other above the first cell terminal 112 of the multiple first cells 110 and above the second cell terminal 212 of the multiple second cells 210 so as to block the space between the multiple first cells 110 and the multiple second cells 210.

Description

Technical Field

[0001] The present disclosure relates to a power storage device.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2020-149934 discloses a conventional battery module. This battery module includes a plurality of secondary batteries and a lower insulating member. The plurality of secondary batteries are arranged in parallel. Each secondary battery has a pressure release valve. The lower insulating member has a partition portion that covers all the pressure release valves arranged in parallel. A smoke exhaust passage is formed between the partition portion and the outer surface of the lid portion of each secondary battery. The smoke exhaust passage is provided to allow the gas discharged from the opened pressure release valve to flow. The plurality of secondary batteries are constrained from both sides in the parallel arrangement direction by a pair of end plates by screwing nuts to through bolts. The through bolts and nuts constitute a restraining member.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In an abnormal mode of a power storage device including a battery module, from the gas discharge location, conductive foreign matter (debris) consisting of fragments of the case of the secondary battery or a part of the contents of the case can scatter along with the exhaust of the gas. In the battery module, it is required to suppress such debris from contacting the terminals of the cells and causing a short circuit. On the other hand, in order to provide a more inexpensive power storage device, it is also required to reduce the number of components of the power storage device.

[0005] This disclosure has been made in view of the above-mentioned problems, and aims to provide an energy storage device that can suppress contact between debris and cell terminals while suppressing an increase in the number of components. [Means for solving the problem]

[0006] An energy storage device according to a certain aspect of the present disclosure comprises a first battery module and a second battery module. The second battery module is located in a first direction perpendicular to the vertical direction with respect to the first battery module. The first battery module includes a plurality of first cells and a first restraining member. The plurality of first cells are arranged in a second direction perpendicular to both the vertical direction and the first direction. Each of the plurality of first cells includes a first cell case and a first cell terminal. The first cell terminal is provided on the first cell case and faces the second battery module. The first restraining member is provided on the first cell case of each of the plurality of first cells to impose a restraining load on the plurality of first cells in the second direction. The second battery module includes a plurality of second cells and a second restraining member. The plurality of second cells are arranged in a second direction. Each of the plurality of second cells includes a second cell case and a second cell terminal. The second cell terminals are provided on the second cell case and face the first battery module. The second restraining member is provided on the second cell case of each of the multiple second cells so as to apply a restraining load to the multiple second cells in the second direction. The first restraining member and the second restraining member are connected to each other above the first cell terminals of the multiple first cells and above the second cell terminals of the multiple second cells, so as to block the space between the multiple first cells and the multiple second cells. [Effects of the Invention]

[0007] According to this disclosure, it is possible to suppress the increase in the number of components while preventing debris from coming into contact with the cell terminals. [Brief explanation of the drawing]

[0008] [Figure 1] This figure schematically shows a vehicle equipped with an energy storage device according to one embodiment of the present disclosure. [Figure 2]This is a perspective view showing the first and second battery modules housed in their cases. [Figure 3] Figure 2 is a cross-sectional view of the first and second battery modules as seen in the direction of the arrow III-III. [Figure 4] This is a cross-sectional view showing a modified energy storage device. [Figure 5] This is a cross-sectional view showing a power storage device relating to another variation. [Modes for carrying out the invention]

[0009] Hereinafter, an energy storage device according to one embodiment of the present disclosure will be described with reference to the drawings. The same or corresponding parts in the drawings are denoted by the same reference numerals, and their descriptions will not be repeated. In addition, each drawing shows the reference numerals "U", "D", and "D1" to "D4", which indicate directions for explaining the configuration of the energy storage device. "U" indicates upward, "D" indicates downward, and "D1", "D2", "D3", and "D4" indicate the first direction, second direction, third direction, and fourth direction, respectively. The first direction is the direction perpendicular to the vertical direction. The second direction is the direction perpendicular to both the vertical direction and the first direction. The third direction is the opposite direction to the first direction. The fourth direction is the opposite direction to the second direction.

[0010] Figure 1 is a schematic diagram showing a vehicle equipped with a power storage device according to one embodiment of the present disclosure. As shown in Figure 1, the vehicle 1 comprises a vehicle frame 5 and a power storage device 10. The power storage device 10 is mounted on the vehicle 1 by being fixed to the vehicle frame 5. The vehicle 1 may be an electric vehicle such as a plug-in hybrid electric vehicle (PHEV) or a battery electric vehicle (BEV). The vehicle 1 is driven by power supplied from the power storage device 10.

[0011] In this embodiment, the first direction in the energy storage device 10 corresponds to the rear of the vehicle 1, but it may correspond to other directions. That is, the first direction in the energy storage device 10 may be the front, left, or right of the vehicle 1.

[0012] An energy storage device 10 according to one embodiment of the present disclosure comprises a case 50, a first battery module 100, a second battery module 200, a third battery module 300, and a fourth battery module 400. The case 50 is fixed to the vehicle frame 5. The case 50 houses the first battery module 100, the second battery module 200, the third battery module 300, and the fourth battery module 400. The case 50 is also called a battery pack.

[0013] From the viewpoint of improving the energy density of the energy storage device 10, it is preferable that the volume ratio occupied by each of the battery modules within the case 50 is large. However, if this volume ratio is large, when debris (details described later) is generated in an abnormal mode of the energy storage device 10, the space in the case 50 where the debris can remain will be smaller. As a result, the debris may more easily reach components of the battery modules located far from where it was generated.

[0014] The second battery module 200 is located in the first direction relative to the first battery module 100. No other battery modules are located between the second battery module 200 and the first battery module 100. The third battery module 300 is located in the third direction relative to the first battery module 100. The fourth battery module 400 is located in the first direction relative to the second battery module 200.

[0015] Details of the first battery module 100 will now be described. Figure 2 is a perspective view showing the first and second battery modules housed in their cases. Figure 3 is a cross-sectional view of the first and second battery modules of Figure 2, viewed in the direction of the arrow III-III.

[0016] As shown in FIGS. 2 and 3, the first battery module 100 includes a plurality of first cells 110, a first end plate 115A, a first other end plate 115B, a first restraint member 120, a first lower restraint member 130, a first other restraint member 140, and a first other lower member restraint member 150.

[0017] The plurality of first cells 110 are arranged in the second direction. Each of the plurality of first cells 110 may be a secondary battery such as a lithium-ion secondary battery or a nickel-metal hydride battery.

[0018] Each of the plurality of first cells 110 includes a first cell case 111, a first cell terminal 112, and a first other cell terminal 113. The first cell case 111 houses an electrode body and an electrolytic solution (both not shown). In the electrode body, a positive electrode and a negative electrode are laminated on each other with a separator interposed therebetween. The first cell case 111 has a substantially rectangular parallelepiped outer shape. Therefore, the first cell 110 is a so-called square cell. A first exhaust valve 111b is formed on the upper surface of the first cell case 111. However, the location where the first exhaust valve 111b is formed is not limited to the upper surface of the first cell case 111.

[0019] The first cell terminal 112 is provided on the first cell case 111 and faces the second battery module 200. The location where the first other cell terminal 113 is provided is not particularly limited. One of the first cell terminal 112 and the first other cell terminal 113 is electrically connected to the positive electrode housed in the first cell case 111, and the other is electrically connected to the negative electrode housed in the first cell case 111.

[0020] The first end plate 115A is located on the tip side in the second direction when viewed from the plurality of first cells 110. The first other end plate 115B is located on the tip side in the fourth direction when viewed from the plurality of first cells 110.

[0021] The first restraint member 120, the first lower restraint member 130, the first other restraint member 140, and the first other lower member restraint member 150 are provided on the first cell case 111 of each of the plurality of first cells 110 so as to apply a restraint load in the second direction. Specifically, the first restraint member 120, the first lower restraint member 130, the first other restraint member 140, and the first other lower member restraint member 150 are fastened to the first end plate 115A and the first other end plate 115B, so that the first end plate 115A applies a load to the plurality of first cells 110 in the fourth direction, and the first other end plate 115B may apply a load to the plurality of first cells 110 in the second direction. These restraint members may be formed of metal. These restraint members may be formed substantially only of metal.

[0022] The first restraint member 120 includes a first restraint main body portion 121 and a first rib 122. The first restraint main body portion 121 extends along the surface of the first cell case 111 of the plurality of first cells 110. Specifically, the first restraint main body portion 121 extends along the upper corner portion of the first cell case 111.

[0023] The first rib 122 extends parallel to the first direction from the first restraint main body portion 121. Specifically, the first rib 122 extends from a portion of the first restraint main body portion 121 that is located laterally (the first direction) when viewed from the first cell case 111.

[0024] The first lower restraint member 130 includes a first lower restraint main body portion 131 and a first lower rib 132. The first lower restraint main body portion 131 extends along the surface of the first cell case 111 of the plurality of first cells 110. Specifically, the first lower restraint main body portion 131 extends along the lower corner portion of the first cell case 111.

[0025] The first lower rib 132 extends parallel to the first direction from the first lower restraint main body portion 131. Specifically, the first lower rib 132 extends from a portion of the first lower restraint main body portion 131 that is located laterally (the first direction) when viewed from the first cell case 111.

[0026] The first other restraining member 140 is positioned symmetrically with respect to the first restraining member 120 in the horizontal direction when viewed from the first cell 110. The first other restraining member 140 may have a configuration that is symmetrical with respect to the first restraining member 120 in the horizontal direction when viewed from a plurality of first cells 110.

[0027] The first other lower member restraint member 150 is positioned symmetrically with respect to the first lower member restraint member 130 in the horizontal direction when viewed from the first cell 110. The first other lower member restraint member 150 may have a configuration symmetrical with respect to the first restraint member 120 in the horizontal direction when viewed from a plurality of first cells 110.

[0028] The second battery module 200 includes a plurality of second cells 210, a second end plate 215A, a second other end plate 215B, a second restraining member 220, a second lower restraining member 230, a second other restraining member 240, and a second other lower restraining member 250. Except for some configurations, these have similar configurations to the plurality of first cells 110, the first end plate 115A, the first other end plate 115B, the first restraining member 120, the first lower restraining member 130, the first other restraining member 140, and the first other lower member restraining member 150 in the first battery module 100. For this reason, similar configurations may not be described again.

[0029] Each of the multiple second cells 210 includes a second cell case 211, a second cell terminal 212, and a second other cell terminal 213. These correspond to the multiple first cells 110, the first cell terminal 112, and the first other cell terminal 113 in each of the multiple first cells 110.

[0030] A second exhaust valve 211b is formed on the upper surface of the second cell case 211. However, the location where the first exhaust valve 111b is formed is not limited to the upper surface of the second cell case 211. The second cell terminal 212 faces the first battery module 100.

[0031] The second restraining member 220 includes a second restraining body portion 221 and a second rib 222. The second restraining body portion 221 extends along the surface of the second cell case 211 of a plurality of second cells 210. Specifically, the second restraining body portion 221 extends along the upper corner of the second cell case 211.

[0032] The second rib 222 extends from the second restraint body 221 parallel to the third direction. Specifically, the second rib 222 extends from the portion of the second restraint body 221 that is located laterally (in the third direction) when viewed from the second cell case 211.

[0033] The second lower restraint member 230 includes a second lower restraint body portion 231 and a second lower rib 232. The second lower restraint body portion 231 extends along the surface of the second cell case 211 of the plurality of second cells 210. Specifically, the second lower restraint body portion 231 extends along the lower corner of the second cell case 211.

[0034] The second lower rib 232 extends parallel to the third direction from the second lower restraint body 231. Specifically, the second lower rib 232 extends from the portion of the second lower restraint body 231 that is located laterally (in the third direction) when viewed from the second cell case 211.

[0035] The second restraining member 240 is positioned symmetrically with respect to the second restraining member 220 in the horizontal direction when viewed from the plurality of second cells 210. The second restraining member 240 may have a configuration that is symmetrical with respect to the second restraining member 220 in the horizontal direction when viewed from the plurality of second cells 210.

[0036] The second lower restraint member 250 is positioned symmetrically with respect to the second lower restraint member 230 in the horizontal direction when viewed from the plurality of second cells 210. The second lower restraint member 250 may have a configuration symmetrical with respect to the second restraint member 220 in the horizontal direction when viewed from the plurality of second cells 210.

[0037] Here, the first restraining member 120 and the second restraining member 220 are connected to each other above the first cell terminals 112 of the plurality of first cells 110 and above the second cell terminals 212 of the plurality of second cells 210, so as to block the space between the plurality of first cells 110 and the plurality of second cells 210. In this embodiment, the first rib 122 and the second rib 222 are in contact with each other in the vertical direction between the plurality of first cells 110 and the plurality of second cells 210. The first restraining member 120 and the second restraining member 220 are joined to each other by laser welding or the like. However, the first restraining member 120 and the second restraining member 220 do not have to be joined to each other.

[0038] Furthermore, the first lower restraint member 130 and the second lower restraint member 230 are connected to each other below the first cell terminals 112 of the plurality of first cells 110 and below the second cell terminals 212 of the plurality of second cells 210, so as to block the space between the plurality of first cells 110 and the plurality of second cells 210. In this embodiment, the first lower rib 132 and the second lower rib 232 are in contact with each other in the vertical direction between the plurality of first cells 110 and the plurality of second cells 210. The first lower restraint member 130 and the second lower restraint member 230 are joined to each other by laser welding or the like. However, the first lower restraint member 130 and the second lower restraint member 230 do not necessarily have to be joined to each other.

[0039] The manner in which the first restraining member 120 and the second restraining member 220 are connected, and the manner in which the first lower restraining member 130 and the second lower restraining member 230 are connected, are not limited to those described above.

[0040] Figure 4 is a cross-sectional view showing a modified energy storage device. The cross-sectional view of the modified device shown in Figure 4 corresponds to the cross-sectional view of one embodiment shown in Figure 3.

[0041] As shown in Figure 4, the first rib 122a of the first restraining member 120a and the second rib 222a of the second restraining member 220a may be aligned in the first direction. A gap may be formed between the first rib 122a of the first restraining member 120a and the second rib 222a of the second restraining member 220a, but this gap can be filled with a first filler 500A, which is a different material from the first restraining member 120a and the second restraining member 220a. That is, the first rib 122a of the first restraining member 120a and the second rib 222a of the second restraining member 220a may be connected to each other by the first filler 500A.

[0042] The first lower rib 132a of the first lower restraint member 130a and the second lower rib 232a of the second lower restraint member 230a may be aligned in the first direction. A gap may be formed between the first lower rib 132a of the first lower restraint member 130a and the second lower rib 232a of the second lower restraint member 230a, but this gap may be filled with a second filler 500B which is a different material from the first lower restraint member 130a and the second lower restraint member 230a. That is, the first lower rib 132a of the first lower restraint member 130a and the second lower rib 232a of the second lower restraint member 230a may be connected to each other by the second filler 500B.

[0043] The first filler 500A and the second filler 500B may be, for example, an adhesive or a sealant.

[0044] Figure 5 is a cross-sectional view showing an energy storage device relating to yet another modification. The cross-sectional view of the other modification shown in Figure 5 corresponds to the cross-sectional view of the modification shown in Figure 4. As shown in Figure 5, the first restraining member 120a, the first lower restraining member 130a, the second restraining member 220a, and the second lower restraining member 230a may further include a first covering material 123, a first lower covering material 133, a second covering material 223, and a second lower covering material 233, respectively. The first covering material 123, the first lower covering material 133, the second covering material 223, and the second lower covering material 233 cover the first rib 122a, the first lower rib 132a, the second rib 222a, and the second lower rib 232a, respectively. These covering materials may be electrically insulating.

[0045] As shown in the other modifications, the first covering material 123 and the second covering material 223 may be butted together so that the first rib 122a of the first restraining member 120a and the second rib 222a of the second restraining member 220a are connected to each other. The first lower covering material 133 and the second lower covering material 233 may be butted together so that the first lower rib 132a of the first lower restraining member 130a and the second lower rib 232a of the second lower restraining member 230a are connected to each other.

[0046] As described above, an energy storage device 10 according to one embodiment of the present disclosure comprises a first battery module 100 and a second battery module 200. The second battery module 200 is located in a first direction perpendicular to the vertical direction when viewed from the first battery module 100. The first battery module 100 includes a plurality of first cells 110 and a first restraining member 120. The plurality of first cells 110 are arranged in a second direction perpendicular to both the vertical direction and the first direction. Each of the plurality of first cells 110 includes a first cell case 111 and a first cell terminal 112. The first cell terminal 112 is provided on the first cell case 111 of each of the plurality of first cells 110 so as to apply a restraining load to the plurality of first cells 110 in the second direction. The second battery module 200 includes a plurality of second cells 210 and a second restraining member 220. The plurality of second cells 210 are arranged in a second direction. Each of the plurality of second cells 210 includes a second cell case 211 and a second cell terminal 212. The second cell terminal 212 is provided on the second cell case 211 and faces the first battery module 100. The second restraining member 220 is provided on the second cell case 211 of each of the plurality of second cells 210 so as to apply a restraining load to the plurality of second cells 210 in a second direction. The first restraining member 120 and the second restraining member 220 are connected to each other above the first cell terminals 112 of the plurality of first cells 110 and above the second cell terminals 212 of the plurality of second cells 210, so as to block the space between the plurality of first cells 110 and the plurality of second cells 210.

[0047] In the abnormal mode of the energy storage device 10, when gas is exhausted upward from inside the first cell case 111 or the second cell case 211, conductive foreign matter (debris) consisting of fragments of the case or parts of the contents of the case may be scattered on the upper side of the case along with the exhaust of gas. In Figure 3, examples of the location of debris generation and scattering routes are indicated by the symbols "DL" and "DR," respectively. Here, because the first restraining member 120 and the second restraining member 220 are connected to each other as described above, contact of such debris with the first cell terminal 112 or the second cell terminal 212 is suppressed. Thus, it is possible to suppress contact of debris with the cell terminals while suppressing an increase in the number of components.

[0048] In this embodiment, the first restraint member 120 includes a first restraint body portion 121 and a first rib 122. The first restraint body portion 121 extends along the surface of the first cell case 111 of the plurality of first cells 110. The first rib 122 extends from the first restraint body portion 121 parallel to the first direction. The second restraint member 220 includes a second restraint body portion 221 and a second rib 222. The second restraint body portion 221 extends along the surface of the second cell case 211 of the plurality of second cells 210. The second rib 222 extends from the second restraint body portion 221 parallel to the third direction opposite to the first direction. The first rib 122 and the second rib 222 are in contact with each other in the vertical direction between the plurality of first cells 110 and the plurality of second cells 210.

[0049] According to the above configuration, the first rib 122 extends relatively far in the first direction from the first restraint body portion 121. For example, compared to the above-described modifications, the first rib 122 in this embodiment is longer in the first direction. This further improves the rigidity of the first restraint body portion 121. Similarly, the second rib 222 also extends relatively far in the third direction from the second restraint body portion 221. For example, compared to the above-described modifications, the second rib 222 in this embodiment is longer in the third direction. This further improves the rigidity of the second rib 222.

[0050] Furthermore, in this embodiment, the first battery module 100 further includes a first lower restraint member 130. The first lower restraint member 130 is provided on the first cell case 111 of each of the plurality of first cells 110 so as to apply a restraining load to the plurality of first cells 110 in a second direction. The second battery module 200 further includes a second lower restraint member 230. The second lower restraint member 230 is provided on the second cell case 211 of each of the plurality of second cells 210 so as to apply a restraining load to the plurality of second cells 210 in a second direction. The first lower restraint member 130 and the second lower restraint member 230 are connected to each other so as to block the space between the plurality of first cells 110 and the plurality of second cells 210 below the first cell terminals 112 of the plurality of first cells 110 and below the second cell terminals 212 of the plurality of second cells 210.

[0051] With the above configuration, the first lower restraining member 130 and the second lower restraining member 230 can prevent debris from coming into contact with the first cell terminal 112 or the second cell terminal 212 from below.

[0052] Furthermore, in this embodiment, the first lower restraint member 130 includes a first lower restraint body portion 131 and a first lower rib 132. The first lower restraint body portion 131 extends along the surface of the first cell case 111 of a plurality of first cells 110. The first lower rib 132 extends from the first lower restraint body portion 131 parallel to the first direction. The second lower restraint member 230 includes a second lower restraint body portion 231 and a second lower rib 232. The second lower restraint body portion 231 extends along the surface of the second cell case 211 of a plurality of second cells 210. The second lower rib 232 extends from the second lower restraint body portion 231 parallel to the third direction opposite to the first direction. The first lower rib 132 and the second lower rib 232 are in contact with each other in the vertical direction between the multiple first cells 110 and the multiple second cells 210.

[0053] According to the above configuration, the first lower rib 132 extends relatively far in the first direction from the first lower restraint body 131. For example, compared to the above-described modifications, the first lower rib 132 in this embodiment is longer in the first direction. This further improves the rigidity of the first lower restraint body 131. Similarly, the second lower rib 232 also extends relatively far in the third direction from the second lower restraint body 231. For example, compared to the above-described modifications, the second lower rib 232 in this embodiment is longer in the third direction. This further improves the rigidity of the second lower rib 232.

[0054] Furthermore, in this embodiment, a first exhaust valve 111b is formed on the upper surface of each first cell case 111 of the plurality of first cells 110. A second exhaust valve 211b is formed on the upper surface of each second cell case 211 of the plurality of second cells 210. The first restraining member 120 and the second restraining member 220 are joined to each other.

[0055] In the above configuration, during abnormal mode, the gas inside the first cell case 111 is more easily exhausted from 111b, and the gas inside the second cell case 211 is more easily exhausted from the second exhaust valve 211b. As a result, the possibility of debris scattering above the first restraining member 120 and the second restraining member 220 increases. However, because the first restraining member 120 and the second restraining member 220 are joined to each other, it is possible to further suppress the debris from coming into contact with the first cell terminal 112 or the second cell terminal 212.

[0056] In the above-described embodiment, the combinatable configurations may be combined with each other.

[0057] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended. [Explanation of symbols]

[0058] 1 Vehicle, 5 Vehicle frame, 10 Energy storage device, 50 Case, 100 First battery module, 110 First cell, 111 First cell case, 111b First exhaust valve, 112 First cell terminal, 113 First other cell terminal, 115A First end plate, 115B First other end plate, 120, 120a First restraining member, 121 First restraining body, 122, 122a First rib, 123 First covering material, 130 First lower restraining member, 130a First lower restraining member, 131 First lower restraining body, 132, 132a First lower rib, 133 First lower covering material, 140 First other restraining member, 150 First other lower member restraining member, 200 Second battery module, 210 Multiple second cells, 211 Second cell case, 211b Second exhaust valve, 212 213 Second cell terminal, 215A Second end plate, 215B Second other end plate, 220, 220a Second restraining member, 221 Second restraining body, 222, 222a Second rib, 223 Second covering material, 230, 230a Second lower restraining member, 231 Second lower restraining body, 232, 232a Second lower rib, 233 Second lower covering material, 240 Second other restraining member, 250 Second other lower restraining member, 300 Third battery module, 400 Fourth battery module, 500A First filler, 500B Second filler.

Claims

1. It is an energy storage device, First battery module and It comprises a second battery module, The second battery module is located in a first direction perpendicular to the vertical direction when viewed from the first battery module. The first battery module includes a plurality of first cells and a first restraining member, The plurality of first cells are arranged in a second direction that is perpendicular to both the vertical direction and the first direction. Each of the plurality of first cells includes a first cell case and first cell terminals. The first cell terminal is provided on the first cell case and faces the second battery module. The first restraining member is provided on each of the first cell cases of the plurality of first cells so as to apply a restraining load to the plurality of first cells in the second direction, The second battery module includes a plurality of second cells and a second restraining member, The plurality of second cells are arranged in the second direction, Each of the aforementioned plurality of second cells includes a second cell case and second cell terminals. The second cell terminal is provided on the second cell case and faces the first battery module. The second restraining member is provided on the second cell case of each of the plurality of second cells so as to apply a restraining load to the plurality of second cells in the second direction, An energy storage device in which the first restraining member and the second restraining member are connected to each other above the first cell terminals of the plurality of first cells and above the second cell terminals of the plurality of second cells, so as to block the space between the plurality of first cells and the plurality of second cells.

2. The first restraining member includes a first restraining body and a first rib. The first restraint body extends along the surface of the first cell case of the plurality of first cells, The first rib extends from the first restraint body portion parallel to the first direction, The second restraining member includes a second restraining body and a second rib. The second restraint body extends along the surface of the second cell case of the plurality of second cells, The second rib extends from the second restraint body portion parallel to the third direction opposite to the first direction, The energy storage device according to claim 1, wherein the first rib and the second rib are in contact with each other in the vertical direction between the plurality of first cells and the plurality of second cells.

3. The first battery module further includes a first lower restraining member, The first lower restraining member is provided on each of the first cell cases of the plurality of first cells so as to apply a restraining load to the plurality of first cells in the second direction, The second battery module further includes a second lower restraining member, The second lower restraining member is provided on the second cell case of each of the plurality of second cells so as to apply a restraining load to the plurality of second cells in the second direction, The energy storage device according to claim 1 or claim 2, wherein the first lower restraining member and the second lower restraining member are connected to each other below the first cell terminals of the plurality of first cells and below the second cell terminals of the plurality of second cells, so as to block the space between the plurality of first cells and the plurality of second cells.

4. The first lower restraint member includes a first lower restraint body and a first lower rib. The first lower restraint body extends along the surface of the first cell case of the plurality of first cells, The first lower rib extends parallel to the first direction from the first lower restraint body portion. The second lower restraint member includes a second lower restraint body and a second lower rib. The second lower restraint body extends along the surface of the second cell case of the plurality of second cells, The second lower rib extends from the second lower restraint body portion parallel to the third direction opposite to the first direction, The energy storage device according to claim 3, wherein the first lower rib and the second lower rib are in contact with each other in the vertical direction between the plurality of first cells and the plurality of second cells.

5. A first exhaust valve is formed on the upper surface of the first cell case of each of the plurality of first cells. A second exhaust valve is formed on the upper surface of the second cell case of each of the plurality of second cells. The energy storage device according to claim 1, wherein the first restraining member and the second restraining member are joined to each other.

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