Power storage device

Abstract

An electricity storage device 1 is provided with an outer body 10 accommodating electricity storage elements 20, and a reinforcing member 100. The reinforcing member 100 includes a pair of reinforcing walls 101 disposed in such a way as to sandwich two mutually opposing wall portions 13 (wall portions 13a) of the outer body 10 from the outside, and linking portions 102 linking the pair of reinforcing walls 101. The rigidity of each of the pair of reinforcing walls 101 is greater than the rigidity of the linking portions 102.

Description

[Technical Field]

[0001] The present invention relates to an energy storage device including an energy storage element and an exterior body that houses the energy storage element. [Background technology]

[0002] Patent Document 1 discloses an electricity storage device that includes a main body that houses a storage battery unit including multiple batteries and a reinforcing structure attached to the main body. This reinforcing structure includes a support that protrudes above the main body and a receiving member fixed to the top of the support, so that even if a heavy object falls on the electricity storage device, the reinforcing structure can withstand the load (impact load), thereby preventing deformation and damage to the main body. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2016 / 186139 Summary of the Invention [Problem to be solved by the invention]

[0004] In the conventional energy storage device described above, a reinforcing structure (reinforcing member) is arranged on the main body (exterior body) in preparation for the case where an object collides with the energy storage device. However, forces act on the exterior body of the energy storage device not only from the outside of the exterior body but also from the inside of the exterior body. When gas is released from the energy storage element inside the exterior body, the pressure inside the exterior body (internal pressure) rises suddenly, and the exterior body is subjected to a force (internal pressure) from the inside. This causes the exterior body to deform and bulge outward, which may result in damage to the exterior body, such as cracks. If the exterior body is damaged, an unsafe event may occur, such as gas inside the exterior body leaking from the damaged portion. Therefore, how to prevent malfunctions of the exterior body caused by such forces from the inside is an important issue from the perspective of improving the safety of the energy storage device.

[0005] The present invention was made by the inventors of the present application by focusing on the above-mentioned problem, and has an object to provide a power storage device with improved safety. [Means for solving the problem]

[0006] A storage device according to one embodiment of the present invention comprises an outer casing that houses a storage element, a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a reinforcing member having a connecting portion that connects the pair of reinforcing walls, wherein the rigidity of each of the pair of reinforcing walls is higher than the rigidity of the connecting portion.

[0007] Another aspect of the present invention provides an energy storage device comprising: an outer casing that houses an energy storage element; and a reinforcing member having a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a connecting portion that connects the pair of reinforcing walls, wherein the reinforcing member has a first reinforcing member and a second reinforcing member, each of the first reinforcing member and the second reinforcing member including two plate-shaped portions arranged opposite each other and the connecting portion that connects the two plate-shaped portions, and each of the pair of reinforcing walls is formed by overlapping one of the two plate-shaped portions of the first reinforcing member and one of the two plate-shaped portions of the second reinforcing member.

[0008] Another aspect of the present invention provides an energy storage device comprising an outer casing that houses an energy storage element, a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a reinforcing member having a connecting portion that connects the pair of reinforcing walls, wherein the thickness of each of the pair of reinforcing walls is greater than the thickness of the connecting portion. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a power storage device with improved safety. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 1 is a perspective view showing the appearance of a power storage device according to an embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the electricity storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the configuration of a reinforcing member and its surroundings according to the embodiment. [Figure 4] FIG. 4 is an exploded perspective view of the reinforcing member according to the embodiment. [Figure 5] FIG. 5 is a first cross-sectional view showing the structural relationship between a reinforcing member and an exterior body according to the embodiment. [Figure 6] FIG. 6 is a second cross-sectional view showing the structural relationship between the reinforcing member and the exterior body according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] A storage device according to one embodiment of the present invention comprises an outer casing that houses a storage element, a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a reinforcing member having a connecting portion that connects the pair of reinforcing walls, wherein the rigidity of each of the pair of reinforcing walls is higher than the rigidity of the connecting portion.

[0012] According to this configuration, the pair of reinforcing walls are connected to each other so as to restrict their outward movement. Therefore, when an external force is applied from the inside to the wall portion of the exterior body, the wall portion is prevented from bulging outward. As a result, the occurrence of defects such as damage to the exterior body is suppressed. Because this effect can be achieved by a reinforcing member attached to the exterior body from the outside, the above effect can be achieved without requiring a change in the design of the exterior body. Furthermore, the relatively high rigidity of the reinforcing walls more reliably suppresses bulging of the wall portion of the exterior body. Furthermore, the connecting portion, which does not require as high rigidity as the reinforcing walls, can be made thinner or hollowed out. In other words, deformation of the exterior body (bulging of the wall portion) can be effectively suppressed while reducing the weight or size of the reinforcing member. Thus, the energy storage device according to this aspect can improve safety.

[0013] The pair of reinforcing walls may be connected by the connecting portions disposed on both sides in a width direction intersecting with the opposing direction of the two wall portions.

[0014] With this configuration, the pair of reinforcing walls are connected on both sides in the width direction, and therefore can exert a high restraining force on the exterior body, which improves the effect of suppressing the expansion of the exterior body and contributes to improving the safety of the energy storage device.

[0015] The storage element may comprise a container having a pair of long sides facing each other, and the outer casing may house a plurality of the storage elements arranged side by side with the pair of long sides facing in the opposing directions of the two wall portions.

[0016] When multiple energy storage elements are housed side by side in an exterior body, rectangular energy storage elements are generally arranged with their long sides facing the arrangement direction. Because rectangular energy storage elements tend to bulge at their long sides, an array of energy storage elements consisting of multiple energy storage elements tends to bulge in the arrangement direction. Therefore, the two opposing wall portions tend to bulge outward due to this bulging. In this regard, in the energy storage device of this aspect, the reinforcing members are positioned in a position suitable for restraining the two wall portions, thereby effectively suppressing bulging of the exterior body. In other words, the reinforcing members are positioned to hold down the parts of the exterior body that are prone to bulge, thereby improving the safety of the energy storage device.

[0017] The reinforcing member may have a first reinforcing member and a second reinforcing member, each of the first reinforcing member and the second reinforcing member including two plate-shaped portions arranged opposite each other and the connecting portion connecting the two plate-shaped portions, and each of the pair of reinforcing walls may be formed by overlapping one of the two plate-shaped portions of the first reinforcing member and one of the two plate-shaped portions of the second reinforcing member.

[0018] According to this configuration, a reinforcing member can be constructed by combining two members (first and second reinforcing members) of the same shape. Therefore, a highly rigid reinforcing wall made of two plate-shaped portions can be obtained. By combining the two members so that the connecting portions face each other, a reinforcing member that suppresses bulging of the exterior body in a balanced manner can be obtained. Therefore, a reinforcing member that efficiently suppresses bulging of the exterior body can be obtained with a simple configuration, which contributes to improving the safety of the energy storage device.

[0019] Another aspect of the present invention provides an energy storage device comprising: an outer casing that houses an energy storage element; and a reinforcing member having a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a connecting portion that connects the pair of reinforcing walls, wherein the reinforcing member has a first reinforcing member and a second reinforcing member, each of the first reinforcing member and the second reinforcing member including two plate-shaped portions arranged opposite each other and the connecting portion that connects the two plate-shaped portions, and each of the pair of reinforcing walls is formed by overlapping one of the two plate-shaped portions of the first reinforcing member and one of the two plate-shaped portions of the second reinforcing member.

[0020] According to this configuration, the pair of reinforcing walls are connected to restrict each other's outward movement, thereby suppressing outward bulging of the wall portion of the exterior body. As a result, damage to the exterior body, etc. is suppressed. A reinforcing member can be configured by combining two members (first and second reinforcing members) of the same shape. Therefore, a highly rigid reinforcing wall made of two plate-shaped portions can be obtained. By combining the two members so that the connecting portions face each other, a reinforcing member that suppresses bulging of the exterior body in a balanced manner can also be obtained. Therefore, a reinforcing member that efficiently suppresses bulging of the exterior body can be obtained with a simple configuration. In this way, the energy storage device according to this aspect can improve safety.

[0021] Another aspect of the present invention provides an energy storage device comprising an outer casing that houses an energy storage element, a pair of reinforcing walls arranged to sandwich two opposing wall portions of the outer casing from the outside, and a reinforcing member having a connecting portion that connects the pair of reinforcing walls, wherein the thickness of each of the pair of reinforcing walls is greater than the thickness of the connecting portion.

[0022] According to this configuration, the pair of reinforcing walls are connected to each other so as to restrict their outward movement. Therefore, when an external force is applied from the inside to the wall portion of the exterior body, the wall portion is prevented from bulging outward. As a result, the occurrence of defects such as damage to the exterior body is suppressed. Because this effect can be achieved by a reinforcing member attached to the exterior body from the outside, the above effect can be achieved without requiring a change in the design of the exterior body. Furthermore, the relatively large thickness of the reinforcing walls more reliably suppresses bulging of the wall portion of the exterior body, and the connecting portion, which does not require as much thickness as the reinforcing walls, can be formed relatively thin. In other words, deformation of the exterior body (bulging of the wall portion) can be effectively suppressed while achieving a reduction in the weight or size of the reinforcing member. Thus, the energy storage device according to this aspect can improve safety.

[0023] Hereinafter, with reference to the drawings, a description will be given of an energy storage device according to an embodiment of the present invention (including its modified examples). The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are merely examples and are not intended to limit the present invention. In each drawing, dimensions and the like are not strictly illustrated.

[0024] In the following description and drawings, the X-axis direction is defined as the arrangement direction of multiple energy storage elements, the direction in which the long sides of the containers of the energy storage elements face each other, or the thickness direction of the container. The Y-axis direction is defined as the arrangement direction of the electrode terminals of one energy storage element, or the direction in which the short sides of the containers of the energy storage elements face each other. The Z-axis direction is defined as the arrangement direction of the main body and the lid in the exterior body of the energy storage device, the arrangement direction of the energy storage elements and the bus bars, or the up-down direction. The X-axis direction, Y-axis direction, and Z-axis direction intersect each other (orthogonal in the following embodiments and their modifications). Depending on the usage mode, the Z-axis direction may not be the up-down direction, but for convenience of explanation, the following description will be made assuming that the Z-axis direction is the up-down direction.

[0025] In the following embodiments, expressions indicating relative directions or attitudes, such as "parallel" and "orthogonal," may be used, but these expressions also include cases where the directions or attitudes are not strictly those of the two directions. "Two directions are parallel" does not only mean that the two directions are completely parallel, but also means that the two directions are substantially parallel, i.e., that there is a difference of about a few percent. In the following description, the "positive side of the X-axis direction" refers to the side of the arrow on the X-axis, and the "negative side of the X-axis direction" refers to the side opposite to the "positive side of the X-axis." The same applies to the Y-axis and Z-axis directions.

[0026] (Embodiment) [1. General description of the power storage device] First, an overall description of a power storage device 1 according to an embodiment will be given with reference to Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the power storage device 1 according to an embodiment. Figure 2 is an exploded perspective view of the power storage device 1 according to an embodiment.

[0027] The power storage device 1 is a device that can be charged with electricity from an external source and can discharge electricity to the outside, and in this embodiment has a substantially rectangular parallelepiped shape. The power storage device 1 may be a battery module (battery assembly) used for power storage, power supply, or the like. Specifically, the power storage device 1 may be used as a battery for driving or starting the engine of a mobile object such as an automobile, motorcycle, personal watercraft, ship, snowmobile, agricultural machinery, construction machinery, or electric railway vehicle. Examples of the automobile include an electric vehicle (EV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and a gasoline-powered automobile. Examples of the electric railway vehicle include a train, a monorail, and a linear motor car. The power storage device 1 may also be used as a stationary battery for home use or a power generator, etc.

[0028] As shown in FIGS. 1 and 2 , the energy storage device 1 includes a plurality of energy storage elements 20, an exterior body 10 that houses the plurality of energy storage elements 20, and a reinforcing member 100 attached to the exterior body 10. In this embodiment, eight energy storage elements 20 are housed in the exterior body 10. The number of energy storage elements 20 included in the energy storage device 1 is not limited to eight. The energy storage device 1 may include one or more energy storage elements 20. In this embodiment, one energy storage element row 24 is formed by the plurality of energy storage elements 20 arranged in the X-axis direction. The energy storage element row 24 may include spacers, insulating films, etc., not shown.

[0029] The exterior body 10 has a main body 12 that houses the energy storage element array 24, and a lid 11, and a bus bar plate 17 is arranged between the energy storage element array 24 housed in the main body 12 and the lid 11. The bus bar plate 17 holds a plurality of bus bars 33, which are covered by bus bar covers 70 and 75. A connection unit 80 including a control circuit and the like is arranged between the bus bar plate 17 and the lid 11.

[0030] The exterior body 10 is a rectangular (box-shaped) container (module case) that forms the outer shell of the energy storage device 1. In other words, the exterior body 10 is a member that fixes the energy storage element array 24, the bus bar plate 17, etc. in predetermined positions and protects them from impacts and the like. The exterior body 10 is formed from an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polystyrene (PS), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene-perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof, or a metal with an insulating coating.

[0031] The lid 11 of the exterior housing 10 is a rectangular member that closes the opening 15 of the main body 12, and has a positive electrode external terminal 91 and a negative electrode external terminal 92. The external terminals 91 and 92 are electrically connected to the plurality of energy storage elements 20 via the connection unit 80 and the bus bar 33, and the energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external terminals 91 and 92. The external terminals 91 and 92 are formed of a conductive member made of metal such as aluminum or an aluminum alloy.

[0032] The cover 11 is provided with a ventilation chamber (not shown) through which gas passing from the inside or outside of the exterior body 10 passes, and an exhaust pipe 90 that connects the inside of the ventilation chamber to the outside of the exterior body 10. Gas inside the exterior body 10 is released to the outside of the exterior body 10 via the ventilation chamber and the exhaust pipe 90. More specifically, the ventilation chamber is provided with a valve member that opens when the pressure inside the exterior body 10 (internal pressure) rises to a predetermined value. Therefore, even if foreign matter such as water or dust flows into the ventilation chamber through the exhaust pipe 90 under normal circumstances, the valve member substantially prevents the foreign matter from flowing into the interior of the exterior body 10. When the internal pressure of the exterior body 10 reaches or exceeds a predetermined value due to the discharge of gas from the energy storage element 20, the valve member opens, and the gas inside the exterior body 10 is released from the ventilation chamber to the outside of the exterior body 10 through the exhaust pipe 90.

[0033] The main body 12 of the exterior body 10 is a rectangular cylindrical housing (casing) with a bottom and an opening 15 formed therein for accommodating the energy storage element array 24. With the opening 15 closed by the lid 11, the periphery of the opening 15 and the lid 11 are joined by thermal welding. This ensures airtightness at the opening 15.

[0034] The energy storage elements 20 are secondary batteries (single cells) that can charge and discharge electricity, and more specifically, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries. The energy storage elements 20 have a flattened rectangular parallelepiped (square) shape, and in this embodiment, eight energy storage elements 20 are arranged in the X-axis direction as described above.

[0035] In this embodiment, the energy storage element 20 includes a metal container 21. The container 21 is a rectangular case having a pair of opposing long sides 21a and a pair of opposing short sides 21b. The container 21 contains an electrode assembly, a current collector, an electrolyte, and the like. In this embodiment, the multiple energy storage elements 20 are aligned in a row in the X-axis direction with their long sides 21a facing the X-axis direction (with their short sides 21b parallel to the X-axis direction).

[0036] The cover plate 21c of the container 21 is provided with metal electrode terminals 22 (positive electrode terminal and negative electrode terminal) electrically connected to the electrode body inside the container 21. The cover plate 21c of the container 21 is further provided with a gas exhaust valve 23 for exhausting gas inside the container 21 to the outside. The gas exhaust valve 23 has the function of opening (opening the valve) to exhaust gas inside the container 21 to the outside of the container 21 when the internal pressure of the container 21 increases due to evaporation of the electrolyte inside the container 21. A gas exhaust valve 23 having such a function is provided for each of the multiple energy storage elements 20. In the present embodiment, as shown in FIG. 2, each of the multiple energy storage elements 20 is arranged in an orientation in which the gas exhaust valve 23 faces the positive side in the Z-axis direction.

[0037] The energy storage element 20 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 20 may be a primary battery that allows stored electricity to be used without the user having to charge it. In this embodiment, the energy storage element 20 is illustrated as having a rectangular parallelepiped (cornered) shape, but the shape of the energy storage element 20 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape, a cylindrical shape, an elongated cylindrical shape, or the like other than a rectangular parallelepiped shape. Furthermore, a laminated energy storage element may be provided in the energy storage device 1 as the energy storage element 20.

[0038] The bus bar 33 is a rectangular plate-like member that is held by the bus bar plate 17 and placed on at least two energy storage elements 20 to electrically connect the electrode terminals 22 of the at least two energy storage elements 20. The material of the bus bar 33 is not particularly limited, and the bus bar 33 may be formed of a metal such as aluminum, an aluminum alloy, copper, a copper alloy, or stainless steel, or a combination thereof, or a conductive material other than a metal. In this embodiment, five bus bars 33 are used to connect two energy storage elements 20 in parallel to form four sets of energy storage element groups, and the four sets of energy storage element groups are connected in series. There is no particular limit to the manner in which the eight energy storage elements 20 are electrically connected, and all eight energy storage elements 20 may be connected in series by seven bus bars.

[0039] The connection unit 80 is a unit having a plurality of bus bars and a control board, etc., and electrically connects the energy storage element array 24 to the external terminals 91 and 92. The control board of the connection unit 80 has a plurality of electrical components, and these electrical components form a detection circuit that detects the state of each energy storage element 20, a control circuit that controls charging and discharging, etc. In this embodiment, the connection unit 80 is fixed to the bus bar plate 17.

[0040] Bus bar plate 17 is a resin member that holds bus bars 33. In the present embodiment, bus bar plate 17 is a member that holds multiple bus bars 33, connection unit 80, and other wiring (not shown), and regulates the positions of these members. Bus bar plate 17 is provided with multiple bus bar openings 17a that hold each of the multiple bus bars 33 and expose a portion of each of the multiple bus bars 33 to the side of the multiple energy storage elements 20.

[0041] A path forming portion 19 is provided at the center of the bus bar plate 17 in the Y axis direction, extending in the X axis direction along the arrangement of the gas discharge valves 23 of the multiple energy storage elements 20 and protruding toward the positive side in the Z axis direction. The path forming portion 19 covers all of the gas discharge valves 23 from the positive side in the Z axis direction. As shown in FIG. 2 , path outlets 18 are provided at the longitudinal ends of the path forming portion 19 on both the positive side and the negative side in the X axis direction. Therefore, gas discharged from the energy storage elements 20 mainly passes through the path outlets 18 and is released to the outside of the exterior body 10 via the above-mentioned ventilation chamber and exhaust pipe 90. The bus bar plate 17 configured in this manner is fixed to the main body 12 of the exterior body 10 by a predetermined method such as adhesive bonding or heat welding.

[0042] Each of the bus bar covers 70 and 75 is a resin member that covers the bus bars 33 from above, and serves to electrically insulate the bus bars 33 from the connection unit 80.

[0043] The reinforcing member 100 is a member that reinforces the exterior body 10. In this embodiment, the reinforcing member 100 is disposed to surround the exterior body 10, and can suppress expansion of the exterior body 10 when the interior pressure of the exterior body 10 attempts to expand. As shown in FIGS. 1 and 2 , a plurality of restricting members 200 are fixed to the reinforcing member 100 according to this embodiment, and these restricting members 200 mainly serve to hold down the lid body 11. Each of the restricting members 200 is fixed to the reinforcing member 100 by welding or fastening with bolts or rivets. In this embodiment, three restricting members 200 are fixed to the reinforcing member 100, and in order to distinguish between the three restricting members 200, different reference numerals (210, 220, 230) are used, as shown in FIG. 2 . In the following description, matters related to the "restricting member 200" apply to each of the restricting members 210, 220, and 230. The configuration of the reinforcing member 100 and its surroundings will be further described below with reference to FIGS.

[0044] [2. Reinforcement member and its surrounding structure] FIG. 3 is a perspective view showing a reinforcing member 100 and its surrounding structure according to an embodiment. FIG. 3 illustrates a state in which the reinforcing member 100 and spacers 151 and 152 are separated from the exterior housing 10. FIG. 4 is an exploded perspective view of the reinforcing member 100 according to an embodiment. FIG. 5 is a first cross-sectional view showing the structural relationship between the reinforcing member 100 according to an embodiment and the exterior housing 10. FIG. 5 simply illustrates a cross-section (a cross-section parallel to the XY plane) at the center of the energy storage device 1 in the up-down direction (Z-axis direction), and each energy storage element 20 is shown in a plan view rather than a cross-section. The restricting member 200 and the spacers 151 and 152 are not shown. FIG. 6 is a second cross-sectional view showing the structural relationship between the reinforcing member 100 according to an embodiment and the exterior housing 10. FIG. 6 illustrates the end on the negative side in the X-axis direction in the cross-section VI-VI of FIG. 5.

[0045] As shown in FIG. 3, the reinforcing member 100 is an annular member in a plan view (when viewed from the positive side in the Z-axis direction) that is formed along the four wall portions 13 of the exterior body 10. Specifically, the reinforcing member 100 has a pair of reinforcing walls 101 that are arranged to sandwich the two opposing wall portions 13 from the outside, and a connecting portion 102 that connects the pair of reinforcing walls 101. In the present embodiment, as shown in FIG. 3, the four wall portions 13 of the exterior body 10 are divided into a pair of wall portions 13a that form the short side surfaces of the exterior body 10 and a pair of wall portions 13b that form the long side surfaces of the exterior body 10. In this case, it can be expressed that the pair of reinforcing walls 101 are arranged to sandwich the two opposing wall portions 13a from the outside.

[0046] The reinforcing member 100 is a member made of a metal such as iron or an aluminum alloy, and is fixed to the exterior housing 10 with spacers 151 and 152 interposed between them, as shown in FIG. 3 . The spacers 151 and 152 are members made of mica or resin, and protect the exterior housing 10 from the reinforcing member 100, which has higher rigidity than the exterior housing 10, and electrically insulate the exterior housing 10 from the reinforcing member 100. As these members, a mica molded product or, like the exterior housing 10, an electrically insulating resin such as PP, PC, or PE is used. The material such as resin that forms the spacers 151 and 152 may contain a material that improves strength, durability, heat resistance, or the like, such as glass fiber.

[0047] In this embodiment, the reinforcing member 100 is configured by combining a first reinforcing member 110 and a second reinforcing member 120, as shown in Figures 4 and 5. Specifically, each of the two reinforcing walls 101 of the reinforcing member 100 is configured by overlapping a plate-shaped portion 111 of the first reinforcing member 110 with a plate-shaped portion 121 of the second reinforcing member 120. One of the two connecting portions 102 of the reinforcing member 100 is a portion that connects the two plate-shaped portions 111 of the first reinforcing member 110, and the other is a portion that connects the two plate-shaped portions 111 of the second reinforcing member 120. In this way, the reinforcing member 100 configured from the first reinforcing member 110 and the second reinforcing member 120 is fixed to the exterior body 10 by the following procedure.

[0048] First, the first reinforcing member 110 and the second reinforcing member 120 are placed in the positions shown in Fig. 5 relative to the exterior body 10. Thereafter, pressure is applied to the first reinforcing member 110 and the second reinforcing member 120 from both sides in the Y-axis direction, and while maintaining this state, the plate-shaped portions 111 and 121, which are overlapped in the X-axis direction, are joined by spot welding or the like. As a result, the exterior body 10 is appropriately fastened by the reinforcing member 100, and the reinforcing member 100 is substantially fixed to the exterior body 10.

[0049] The work of attaching such a reinforcing member 100 is performed with the energy storage element array 24, the connection unit 80, etc. housed inside the exterior body 10 and the lid 11 joined to the opening 15 of the main body 12. During the work of attaching the reinforcing member 100, the positions of the first reinforcing member 110 and the second reinforcing member 120 in the up-down direction (Z-axis direction) can be determined by ribs 13e (see FIGS. 3 and 6) provided on the outer surface of the wall 13 of the main body 12. The method of joining the plate-shaped portion 111 and the plate-shaped portion 121 is not limited to welding, and fastening using bolts or rivets may also be adopted as the joining method.

[0050] As described above, in the reinforcing member 100 according to the present embodiment, each of the pair of reinforcing walls 101 arranged opposite to each other is configured by overlapping and joining the plate-like portions 111 and 121. Therefore, it has higher rigidity than the connecting portion 102, which is a single plate-like portion. In terms of thickness, the thickness of the reinforcing walls 101 is greater than the thickness of the connecting portion 102. This allows the connecting portion 102 to exert its restraining function on the two reinforcing walls 101, while also improving the effectiveness of the reinforcing walls 101 in suppressing the expansion of the exterior body 10.

[0051] As described above, the energy storage device 1 according to this embodiment includes an exterior body 10 that houses the energy storage elements 20, and a reinforcing member 100. The reinforcing member 100 has a pair of reinforcing walls 101 that are arranged to sandwich from the outside two opposing wall portions 13 (wall portions 13a) of the exterior body 10, and a connecting portion 102 that connects the pair of reinforcing walls 101. The rigidity of each of the pair of reinforcing walls 101 is higher than the rigidity of the connecting portion 102.

[0052] According to this configuration, the pair of reinforcing walls 101 are connected to each other so as to restrict their outward movement. Therefore, when wall portion 13a of exterior body 10 is subjected to a force from the inside (internal pressure of exterior body 10 or a pressing force due to the expansion of one or more energy storage elements 20), outward bulging of wall portion 13a is suppressed. As a result, the occurrence of defects such as damage to exterior body 10 is suppressed. When an energy storage element 20 inside exterior body 10 opens and gas is discharged, the internal pressure of exterior body 10, which is in an airtight or quasi-airtight state, increases rapidly. In this case, the discharge of gas from exhaust pipe 90 may not keep up with the increase in internal pressure, causing the internal pressure of exterior body 10 to increase or remain high. In this case, damage such as cracks may occur in resin exterior body 10, and gas may leak from the damaged area. In other words, gas may leak from unexpected locations in exterior body 10, which poses a safety issue. However, in the energy storage device 1 according to the present embodiment, the reinforcing member 100 fixed to the exterior body 10 suppresses the expansion of the exterior body 10, thereby reducing the possibility of damage such as cracks occurring in the exterior body 10. Because such an effect can be obtained by the reinforcing member 100 attached to the exterior body 10 from the outside, the above effect can be obtained without, for example, changing the design of the exterior body 10.

[0053] Furthermore, since the reinforcing wall 101 has a relatively high rigidity, it is possible to more reliably suppress bulging of the wall portion 13 of the exterior body 10. Furthermore, it is possible to reduce the thickness of the connecting member 102, which does not require as high rigidity as the reinforcing wall 101, or to provide a lighter portion. As shown in FIG. 3, the connecting member 102 may have four lighter portions (openings) to reduce its weight. That is, in the energy storage device 1 of this embodiment, it is possible to effectively suppress deformation of the exterior body 10 (bulging of the wall portion 13) while achieving a reduction in the weight or size of the reinforcing member 100. In this way, the energy storage device 1 of this embodiment can improve safety.

[0054] The rigidity of the reinforcing walls 101 and the connecting portions 102 is compared by comparing the values of the bending rigidity of each of the reinforcing walls 101 and the connecting portions 102. The bending rigidity of the reinforcing walls 101 refers to the bending rigidity in the arrangement direction (X-axis direction) of the reinforcing walls 101 and the exterior housing 10. The bending rigidity of the connecting portions 102 refers to the bending rigidity in the arrangement direction (Y-axis direction) of the connecting portions 102 and the exterior housing 10. Specifically, in the reinforcing member 100, the pair of reinforcing walls 101 and the connecting portions 102 are cut at their connecting portions to separate the pair of reinforcing walls 101 and the connecting portions 102. Thereafter, the bending rigidity of each of the pair of reinforcing walls 102 and the connecting portions 102 is measured, and the values of the bending rigidity obtained by the measurement are compared. Such a difference in rigidity may be achieved by a difference in thickness between the reinforcing walls 101 and the connecting portions 102, as in the present embodiment, or by a difference in cross-sectional shape (second moment of area) or material between the reinforcing walls 101 and the connecting portions 102.

[0055] In this embodiment, the pair of reinforcing walls 101 are connected by connecting portions 102 arranged on both sides in the width direction (Y-axis direction) that intersects with the opposing direction of the two wall portions 13.

[0056] As described above, in the present embodiment, the pair of reinforcing walls 101 are each oriented parallel to the YZ plane and are connected on both sides in the Y-axis direction, and therefore can exert a high restraining force on the exterior body 10. This improves the effect of suppressing the expansion of the exterior body 10, which contributes to improving the safety of the energy storage device 1.

[0057] In the present embodiment, as shown in FIG. 2, exterior body 10 houses a plurality of energy storage elements 20 arranged side by side in the opposing direction of two wall portions 13 (wall portions 13a).

[0058] Specifically, in the exterior body 10, each of the multiple energy storage elements 20 is a rectangular energy storage element 20, and is arranged with its long side surface 21a (see FIG. 2) facing the arrangement direction. Because the long side surface 21a of these rectangular energy storage elements 20 is prone to bulging, an energy storage element array 24 consisting of the multiple energy storage elements 20 is prone to bulging in the arrangement direction. Therefore, it can be said that the two opposing wall portions 13a are prone to bulging outward due to this bulging. In this regard, in the energy storage device 1 according to this embodiment, the reinforcing member 100 is arranged in a position suitable for restraining the two wall portions 13a, and therefore bulging of the exterior body 10 can be effectively suppressed. In other words, the reinforcing member 100 is arranged to press down on the parts of the exterior body 10 that are prone to bulging, thereby improving the safety of the energy storage device 1.

[0059] In this embodiment, the reinforcing member 100 has a first reinforcing member 110 and a second reinforcing member 120. Each of the first reinforcing member 110 and the second reinforcing member 120 includes two plate-shaped portions 111 or 121 arranged opposite each other and a connecting portion 102 connecting the two plate-shaped portions 111 or 121. Each of the pair of reinforcing walls 101 is formed by overlapping one of the two plate-shaped portions 111 of the first reinforcing member 110 and one of the two plate-shaped portions 121 of the second reinforcing member 120.

[0060] According to this configuration, the reinforcing member 100 can be configured by combining two members (first and second reinforcing members 120) of the same shape. Therefore, a highly rigid reinforcing wall 101 made up of two plate-like portions 111 and 121 can be obtained. By combining the two members so that the connecting portions 102 face each other, it is also possible to obtain a reinforcing member 100 that suppresses bulging of the exterior body 10 in a balanced manner. Therefore, a reinforcing member 100 that efficiently suppresses bulging of the exterior body 10 can be obtained with a simple configuration, which contributes to improving the safety of the energy storage device 1.

[0061] The configuration of the energy storage device 1 according to this embodiment can also be described as follows. That is, the energy storage device 1 includes an exterior housing 10 that houses the energy storage elements 20, and a reinforcing member 100 that has a pair of reinforcing walls 101 and a connecting portion 102. The pair of reinforcing walls 101 are arranged to sandwich two opposing wall portions 13 (wall portions 13a) of the exterior housing 10 from the outside. The connecting portion 102 connects the pair of reinforcing walls 101. The reinforcing member 100 includes a first reinforcing member 110 and a second reinforcing member 120. The first reinforcing member 110 includes two plate-shaped portions 111 arranged opposite to each other and a connecting portion 102 connecting the two plate-shaped portions 111. The second reinforcing member 120 includes two plate-shaped portions 121 arranged opposite to each other and a connecting portion 102 connecting the two plate-shaped portions 121. Each of the pair of reinforcing walls 101 is formed by overlapping one of the two plate-shaped portions 111 of the first reinforcing member 110 and one of the two plate-shaped portions 121 of the second reinforcing member 120.

[0062] According to this configuration, the pair of reinforcing walls 101 are connected to each other in a manner that restricts their outward movement, thereby suppressing outward bulging of the wall portion 13a of the exterior body 10. As a result, damage to the exterior body 10 is suppressed. The reinforcing member 100 can be configured by combining two members (first and second reinforcing members 120) of the same shape. Therefore, a highly rigid reinforcing wall 101 made up of two plate-shaped portions 111 and 121 can be obtained. By combining the first reinforcing member 110 and the second reinforcing member 120 so that the connecting portions 102 face each other, a reinforcing member 100 that suppresses bulging of the exterior body 10 in a balanced manner can be obtained. Therefore, a reinforcing member 100 that efficiently suppresses bulging of the exterior body 10 can be obtained with a simple configuration. Therefore, the energy storage device 1 according to this embodiment can improve safety.

[0063] The configuration of the energy storage device 1 according to this embodiment can also be described as follows. That is, the energy storage device 1 includes an exterior body 10 that houses the energy storage elements 20, and a reinforcing member 100. The reinforcing member 100 has a pair of reinforcing walls 101 that are arranged to sandwich from the outside two opposing wall portions 13 (wall portions 13a) of the exterior body 10, and a connecting portion 102 that connects the pair of reinforcing walls 101. The thickness of each of the pair of reinforcing walls 101 is greater than the thickness of the connecting portion 102.

[0064] According to this configuration, the pair of reinforcing walls 101 are connected to each other so as to restrict their outward movement. This suppresses outward bulging of the wall portion 13a of the exterior body 10 when an external force is applied to the wall portion 13a from the inside. As a result, the occurrence of defects such as damage to the exterior body 10 is suppressed. Because this effect can be achieved by the reinforcing member 100 attached to the exterior body 10 from the outside, the above effect can be achieved without requiring a design change to the exterior body 10. Furthermore, the relatively large thickness of the reinforcing wall 101 more reliably suppresses bulging of the wall portion 13 of the exterior body 10. Furthermore, the connecting portion 102, which does not require a thickness as large as that of the reinforcing wall 101, can be formed relatively thin. In other words, deformation of the exterior body 10 (bulging of the wall portion 13) can be effectively suppressed while achieving a reduction in the weight or size of the reinforcing member 100. Therefore, the energy storage device 1 according to this embodiment can improve safety.

[0065] The thickness of the reinforcing wall 101 is the width of the reinforcing wall 101 in the direction in which the pair of reinforcing walls 101 are aligned. The thickness of the reinforcing wall 101 is the width in the direction in which the reinforcing wall 101 is aligned, of the main part excluding protrusions that protrude in the direction in which the reinforcing wall 101 is aligned, through holes that penetrate the direction in which the reinforcing wall 101 is aligned, and recesses that are recessed in the direction in which the reinforcing wall 101 is aligned. If there is a distribution in the thickness of the reinforcing wall 101 when viewed from the direction in which the reinforcing wall 101 is aligned, the thickness may be the average value or the mode of the thickness in the distribution.

[0066] In the present embodiment, the reinforcing wall 101 that is thicker than the connecting portion 102 is configured by overlapping the plate-like portions 111 and 121, but the reinforcing wall 101 may be configured from a single member. The reinforcing member 100 having the reinforcing wall 101 that is thicker than the connecting portion 102 may be manufactured by using a metal plate in which thick and thin portions are formed by press working.

[0067] In this embodiment, more specifically, the lid 11 and the main body 12 of the exterior body 10 are joined to each other at a joint 14 located on the periphery of the opening 15 (see FIG. 2 ) of the exterior body 10, as shown in FIG. 6 . For example, the joint 14, which is the portion where the lid 11 and the main body 12 are joined to each other, is formed by thermal welding. In this configuration, when the internal pressure of the exterior body 10 increases, the internal pressure acts on the wall 13a in FIG. 6 in a direction that causes the upper end to collapse outward. Therefore, stress is likely to concentrate at the joint 14, which may result in damage to a portion of the joint 14 and cause gas that has filled the interior of the exterior body 10 to leak from that portion of the joint 14. However, in the energy storage device 1 according to this embodiment, as shown in FIG. 6 , a reinforcing member 100 with relatively high rigidity is disposed in a position that presses the wall 13a from the outside, thereby suppressing outward deformation of the wall 13a. As a result, damage such as cracking at the joint 14, which is a portion that is prone to damage due to outward deformation of the wall portion 13a, is suppressed.

[0068] Furthermore, in this embodiment, as shown in Fig. 6, a restricting member 200 is disposed on the outside of the reinforcing member 100. The restricting member 200 has a contact portion 201 that contacts the upper surface of the lid 11 and a fixing portion 202 that is fixed to the reinforcing member 100. The fixing portion 202 is joined to the outer surface of the reinforcing wall 101 of the reinforcing member 100 by welding or the like. Therefore, the restricting member 200 functions as a member that improves the rigidity of the reinforcing wall 101 or a member that increases the thickness of the reinforcing wall 101. In other words, the fixing portion 202 of the restricting member 200 can improve the reinforcing function of the reinforcing member 100.

[0069] Fixing portion 202 of restricting member 200 further has a portion that abuts peripheral wall 11b of lid 11 from the outside. Therefore, if the combination of wall 13a, which is part of main body 12, and peripheral wall 11b of lid 11 is considered to be wall 16 of exterior body 10, and restricting member 200 fixed to reinforcing member 100 by welding or the like is considered to be part of reinforcing member 100, the following can be said: Reinforcing member 100 has a pair of reinforcing walls 101 arranged to sandwich two opposing wall portions 16 of exterior body 10 from the outside, and connecting portion 102 connecting the pair of reinforcing walls 101. In other words, restricting member 200 as part of reinforcing member 100 can function as a member that suppresses outward deformation of peripheral wall 11b of lid 11, which is part of wall 16 of exterior body 10. Specifically, deformation of peripheral wall 11b of lid 11 (tilting of the lower end of peripheral wall 11b so as to open outward) accompanying outward deformation of wall 13a of main body 12 is suppressed by restricting member 200 as part of reinforcing member 100. In this way, reinforcing member 100 according to the present embodiment can suppress bulging of wall 16 formed by main body 12 and lid 11, thereby improving the safety of electricity storage device 1.

[0070] (Variation) The above describes the power storage device according to the present invention based on the embodiment. However, the present invention is not limited to the above embodiment. As long as it does not deviate from the spirit of the present invention, various modifications that a person skilled in the art can make to the above embodiment are also included in the scope of the present invention.

[0071] The two connecting portions 102 of the reinforcing member 100 do not need to be arranged opposite each other. The reinforcing member 100 may have a connecting portion 102 connecting the ends of the pair of reinforcing walls 101 on the negative side in the Y-axis direction, and a connecting portion 102 connecting the ends of the pair of reinforcing walls 101 on the negative side in the Z-axis direction. The number of connecting portions 102 of the reinforcing member 100 may be one, or may be three or more. In other words, the connecting portion 102 only needs to connect the pair of reinforcing walls 101 arranged opposite each other in the X-axis direction so as to restrain the pair of reinforcing walls 101 in the X-axis direction, and there are no particular limitations on the shape, number, arrangement position, etc. of the connecting portion 102.

[0072] The reinforcing member 100 does not have to be configured by combining the first reinforcing member 110 and the second reinforcing member 120. The connecting portion 102 and the reinforcing wall 101 may be fabricated as separate members, and then the connecting portion 102 and the reinforcing wall 101 may be connected by welding, fastening, or the like. In other words, as long as the reinforcing member 100 has a pair of reinforcing walls 101 and at least one connecting portion 102 connecting the pair of reinforcing walls 101, and the stiffness of the reinforcing walls 101 is higher than the stiffness of the connecting portion 102, there are no particular limitations on the number or shape of the components constituting the reinforcing member 100. In this supplementary note, "if the stiffness of the reinforcing walls 101 is higher than the stiffness of the connecting portion 102" may be read as "if the thickness of the reinforcing wall 101 is greater than the thickness of the connecting portion 102." In either case, the reinforcing member 100 can effectively suppress deformation of the exterior body 10 (bulging of the wall portion 13), thereby improving the safety of the energy storage device 1.

[0073] The reinforcing member 100 and the restricting member 200 do not necessarily have to be made of metal, but may be made of a highly rigid non-metallic material such as fiber-reinforced plastic.

[0074] The power storage device 1 does not necessarily have to include the restricting member 200. By including at least the reinforcing member 100 as a member that reinforces the exterior body 10, the power storage device 1 can improve safety as described above.

[0075] Any combination of the above-described components is also included within the scope of the present invention. [Industrial Applicability]

[0076] The present invention can be applied to an electricity storage device including an electricity storage element such as a lithium ion secondary battery. [Explanation of symbols]

[0077] 1. Energy storage device 10. Exterior body 11 Lid 11b Peripheral wall part 12 Main body 13, 13a, 13b, 16 wall section 13e Rib 14 Joint 15 Opening 20 Energy storage element 21 Container 21a long side 100 Reinforcing member 101 Reinforced Wall 102 Connection part 110 First reinforcing member 111, 121 Plate-shaped part 120 Second reinforcing member 200, 210, 220, 230 Regulating member 201 Contact part 202 Fixed part

Claims

1. an exterior body that houses the energy storage element; a pair of reinforcing walls arranged to sandwich two opposing wall portions of the exterior body from the outside, and a reinforcing member having a connecting portion connecting the pair of reinforcing walls, The rigidity of each of the pair of reinforcing walls is higher than the rigidity of the connecting portion, The reinforcing member is made of metal. Energy storage device.

2. The pair of reinforcing walls are connected by the connecting portions disposed on both sides in a width direction intersecting a direction in which the two wall portions face each other. The electricity storage device according to claim 1.

3. The energy storage element includes a container having a pair of long sides facing each other, The exterior housing accommodates a plurality of the energy storage elements arranged side by side such that the pair of long side surfaces face in opposing directions of the two wall portions. The electricity storage device according to claim 1 or 2.

4. the reinforcing member includes a first reinforcing member and a second reinforcing member; each of the first reinforcing member and the second reinforcing member includes two plate-shaped portions arranged opposite to each other and the connecting portion connecting the two plate-shaped portions; Each of the pair of reinforcing walls is formed by overlapping one of the two plate-shaped portions of the first reinforcing member and one of the two plate-shaped portions of the second reinforcing member. The electricity storage device according to any one of claims 1 to 3.

5. an exterior body that houses the energy storage element; a pair of reinforcing walls arranged to sandwich two opposing wall portions of the exterior body from the outside, and a reinforcing member having a connecting portion connecting the pair of reinforcing walls, the reinforcing member includes a first reinforcing member and a second reinforcing member; each of the first reinforcing member and the second reinforcing member includes two plate-shaped portions arranged opposite to each other and the connecting portion connecting the two plate-shaped portions; each of the pair of reinforcing walls is formed by overlapping one of the two plate-shaped portions of the first reinforcing member and one of the two plate-shaped portions of the second reinforcing member, The reinforcing member is made of metal. Energy storage device.

6. an exterior body that houses the energy storage element; a pair of reinforcing walls arranged to sandwich two opposing wall portions of the exterior body from the outside, and a reinforcing member having a connecting portion connecting the pair of reinforcing walls, The thickness of each of the pair of reinforcing walls is greater than the thickness of the connecting portion, The reinforcing member is made of metal. Energy storage device.

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