Power storage device

Abstract

A power storage device (1) is provided with: an electrical storage element unit (25) composed of a plurality of electrical storage elements (20) arranged in a first direction; an outer case (10); and a reinforcement member (40) fixed to the outer case (10). The outer case (10) has an outer surface on which outer electrode terminals (91 and 92) electrically connected to the electrical storage element unit (25) are disposed. The reinforcement member (40) is disposed along a bottom wall portion (32) which is a wall portion separating the inside and outside of the outer case (10). The reinforcement member (40) includes a reinforcement body portion (45) and a protruding portion (46). The reinforcement body portion (45) is a plate-like portion sized to cover the electrical storage element unit (25) when the reinforcement member (40) is viewed from a second direction in which the bottom wall portion (32) and the reinforcement member (40) are arranged. The protruding portion (46) is a portion protruding on the outside of the electrical storage element unit (25) when the reinforcement member (40) is viewed from the second direction.

Description

[Technical Field]

[0001] The present invention relates to an energy storage device including an energy storage element unit made up of a plurality of energy storage elements. [Background technology]

[0002] Conventionally, electric storage devices including a plurality of electric storage elements have been known. For example, Patent Document 1 discloses an electric storage device module including an insulating holder that integrates two or more electric storage devices. Patent Document 1 describes that the electric storage device module has an overall shape that is easy to handle and has improved mechanical or structural strength by including the holder. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-81762 Summary of the Invention [Problem to be solved by the invention]

[0004] In an energy storage device, when a holder is provided that surrounds multiple energy storage elements from the sides, as in Patent Document 1, the impact resistance is improved compared to when no holder is provided. However, when an impact is applied to the energy storage elements from the side, the impact load is applied to the wall portion that constitutes the holder in the thickness direction, which makes the holder prone to deformation.

[0005] The present invention was made by the inventor of the present application by focusing on the above-mentioned problem, and aims to provide a storage device having a plurality of storage elements and having improved safety. [Means for solving the problem]

[0006] An energy storage device according to one embodiment of the present invention comprises an energy storage element unit composed of a plurality of energy storage elements arranged in a first direction, an exterior body that houses the energy storage element unit therein and has external electrode terminals on its outer surface that are electrically connected to the energy storage element unit, and a reinforcing member that is arranged along a wall that separates the inside and outside of the exterior body and is fixed to the exterior body, wherein the reinforcing member includes a plate-shaped reinforcing main body portion formed to a size that covers the energy storage element unit when viewed from a second direction that is the alignment direction of the wall portion and the reinforcing member, and a protrusion that protrudes outward beyond the energy storage element unit.

[0007] An energy storage device according to one aspect of the present invention comprises an energy storage element unit composed of a plurality of energy storage elements arranged in a first direction; an exterior body that houses the energy storage element unit therein and has external electrode terminals on its outer surface that are electrically connected to the energy storage element unit; and a reinforcing member that is arranged along a wall that separates the inside and outside of the exterior body and is fixed to the exterior body, wherein the reinforcing member includes a protrusion that protrudes outward beyond the energy storage element unit when viewed from a second direction that is the alignment direction of the wall and the reinforcing member, and is arranged along the outer surface of another wall adjacent to the wall. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a power storage device with improved safety. [Brief explanation of the drawings]

[0009] [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 showing each component of the electricity storage device according to the embodiment. [Figure 3] FIG. 3 is a perspective view showing the inside of an exterior body according to the embodiment. [Figure 4] FIG. 4 is a perspective view of the electricity storage device according to the embodiment as viewed obliquely from below. [Figure 5]FIG. 5 is a bottom view showing the positional and dimensional relationship between the reinforcing member and the energy storage element unit according to the embodiment. [Figure 6] FIG. 6 is a cross-sectional view of a fixing point of a reinforcing member in an exterior body according to an embodiment. [Figure 7] FIG. 7 is a perspective view showing a configuration of a power storage device according to a first modification of the embodiment. [Figure 8] FIG. 8 is a diagram showing a cross-sectional shape of a reinforcing member according to the first modification of the embodiment. [Figure 9] FIG. 9 is a perspective view showing a configuration of a power storage device according to a second modification of the embodiment. [Figure 10] FIG. 10 is a diagram showing a cross-sectional shape of a reinforcing member according to the second modification of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] An energy storage device according to one embodiment of the present invention comprises an energy storage element unit composed of a plurality of energy storage elements arranged in a first direction, an exterior body that houses the energy storage element unit therein and has external electrode terminals on its outer surface that are electrically connected to the energy storage element unit, and a reinforcing member that is arranged along a wall that separates the inside and outside of the exterior body and is fixed to the exterior body, wherein the reinforcing member includes a plate-shaped reinforcing main body portion formed to a size that covers the energy storage element unit when viewed from a second direction that is the alignment direction of the wall portion and the reinforcing member, and a protrusion that protrudes outward beyond the energy storage element unit.

[0011] According to this configuration, the energy storage device has a reinforcing member arranged along the wall of the exterior body, and the reinforcing member has a protruding portion that protrudes (extends out) from the energy storage element unit when viewed from the side of the energy storage element unit. Therefore, if an object collides with the energy storage device from the protruding direction of the protrusion, the protrusion can receive the impact before the energy storage element unit receives the impact, and further, the plate-shaped reinforcing main body can absorb the impact in a direction perpendicular to the plate thickness direction. This allows efficient protection of all of the multiple energy storage elements included in the energy storage element unit. In this way, the energy storage device according to this aspect is an energy storage device with improved safety.

[0012] The protrusion may protrude outward beyond the energy storage element unit in the first direction.

[0013] In a storage element unit, when the storage elements are arranged in a first direction, the long sides of the multiple storage elements are generally arranged facing the first direction. In a storage element unit configured in this manner, the protrusions are arranged to protrude outward from the storage element unit in the first direction. This protects the long sides, which are weaker parts of the storage elements, from impact. Therefore, the safety of the storage device is improved.

[0014] In the exterior body, the wall portion may be a bottom wall portion on an inner surface of which the energy storage element unit is placed.

[0015] According to this configuration, when the reinforcing member is made of a high-strength metal, even if the energy storage device is deformed due to a collision or the like, problems with electrical continuity between the reinforcing member and the bus bars electrically connected to the energy storage element units are unlikely to occur, which is advantageous in improving the safety of the energy storage device.

[0016] The reinforcing member may be arranged within an outer edge of the exterior body when viewed from the second direction.

[0017] According to this configuration, the reinforcing member is provided in a manner that suppresses an increase in the overall size of the exterior body. Therefore, if the exterior body is formed to a size that complies with some standard, the reinforcing member can be contained within that size. Therefore, a power storage device with improved practicality and safety can be obtained.

[0018] The reinforcing member may be disposed along an outer surface of the wall portion.

[0019] According to this configuration, the reinforcing member is disposed on the outside of the exterior body, so that the reinforcing member can be disposed without consuming the volume inside the exterior body. Conduction problems between the metal reinforcing member and the energy storage element unit are also unlikely to occur. It is also possible to retrofit the reinforcing member to the finished energy storage device. This allows the reinforcing member to be selected and disposed on the exterior body in a shape or size that suits the placement position or environment of the energy storage device. Therefore, an energy storage device with improved practicality and safety can be obtained.

[0020] The protrusion may be provided along an outer surface of another wall portion adjacent to the wall portion.

[0021] According to this configuration, the reinforcing member has, for example, a reinforcing main body portion along the bottom wall portion and a protruding portion along the side wall portion, and therefore has, for example, a peripheral edge portion having an L-shaped cross section. This improves the strength of the reinforcing member, thereby improving the safety of the power storage device.

[0022] An energy storage device according to one aspect of the present invention comprises an energy storage element unit composed of a plurality of energy storage elements arranged in a first direction; an exterior body that houses the energy storage element unit therein and has external electrode terminals on its outer surface that are electrically connected to the energy storage element unit; and a reinforcing member that is arranged along a wall that separates the inside and outside of the exterior body and is fixed to the exterior body, wherein the reinforcing member includes a protrusion that protrudes outward beyond the energy storage element unit when viewed from a second direction that is the alignment direction of the wall and the reinforcing member, and is arranged along the outer surface of another wall adjacent to the wall.

[0023] According to this configuration, the reinforcing member has a portion that fits along the wall portion and a protruding portion that fits along the other wall portion, and therefore has a peripheral portion that has, for example, an L-shaped cross section. This improves the strength of the reinforcing member and allows it to be attached so as to cover the outer periphery of the wall portion. In other words, the reinforcing member can be easily attached to the exterior body, thereby improving the safety of the energy storage device.

[0024] The exterior body may be made of resin, and the reinforcing member may be made of metal.

[0025] According to this configuration, since the exterior body is made of resin, it is easy to form it into a shape that suits the installation location or purpose of use of the energy storage device, and it is easy to electrically insulate the internal energy storage elements, etc. from the external conductive member. Since the reinforcing member is made of metal, it is highly effective in protecting or reinforcing the resin exterior body.

[0026] 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 modifications thereof). The embodiments described below all show 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.

[0027] In the following description and drawings, the Y-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 X-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 lid in the exterior body of the energy storage device, the longitudinal direction of the short sides, 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.

[0028] 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. For example, "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., include a difference of, for example, about several percent.

[0029] In the following description, for example, 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.

[0030] (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 showing each component of the power storage device 1 according to an embodiment.

[0031] The power storage device 1 is a device that can be charged with electricity from an external source and can discharge electricity to an external source. Specifically, the power storage device 1 is used as a battery for driving or starting the engine of a mobile object such as an automobile, a motorcycle, a personal watercraft, a snowmobile, agricultural machinery, construction machinery, or a rolling stock for an electric railway. 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 rolling stock for an electric railway include a train, a monorail, and a linear motor car. The power storage device 1 can also be used as a stationary battery for home use or for a power generator, etc.

[0032] As shown in FIGS. 1 and 2 , the energy storage device 1 includes a plurality of energy storage elements 20 and an exterior body 10 that houses the plurality of energy storage elements 20. In this embodiment, four energy storage elements 20 arranged in the Y-axis direction are housed in the exterior body 10, and these four energy storage elements 20 form one energy storage element unit 25. The Y-axis direction is an example of a first direction. The number of energy storage elements 20 included in the energy storage device 1 is not limited to four. The energy storage device 1 may include a plurality of energy storage elements 20.

[0033] The exterior body 10 has an exterior body main body 30 that houses the energy storage element unit 25, and a lid body 11 that closes the opening of the exterior body main body 30 when the energy storage element unit 25 is housed therein. Between the energy storage element unit 25 and the lid body 11, there are arranged bus bars that electrically connect two or more energy storage elements 20, a bus bar plate that holds the multiple bus bars, and a control circuit that is arranged between the bus bar plate and the lid body 11, but these are not shown in the figure.

[0034] 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 unit 25 and the like in predetermined positions and protects them from impacts and the like. The exterior body 10 is formed from an insulating member 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.

[0035] The exterior body main body 30 of the exterior body 10 is a container made up of multiple walls formed from the insulating member described above, and insulates the energy storage element unit 25 and the like from the outside. The multiple walls include a pair of side walls 31 facing each other in the X-axis direction, a pair of side walls 31 facing each other in the Y-axis direction, and a bottom wall 32 located on the negative side in the Z-axis direction. These four side walls 31 and one bottom wall 32 are integrated to form the exterior body main body 30, which is a box-shaped container.

[0036] The lid 11 of the exterior housing 10 is a rectangular member that closes the opening of the exterior housing main body 30 and is fixed to the exterior housing main body 30 by a predetermined method such as welding or adhesive. A top wall 12, which is a part of the lid 11, functions as a wall that separates the interior and exterior of the exterior housing 10, similar to the four side walls 31 and one bottom wall 32 of the exterior housing main body 30. A positive external electrode terminal 91 and a negative external electrode terminal 92 are disposed on the outer surface of the lid 11. The external electrode terminals 91 and 92 are electrically connected to the energy storage element unit 25 via a bus bar or the like, and the energy storage device 1 charges with electricity from the outside and discharges electricity to the outside via these external electrode terminals 91 and 92. The external electrode terminals 91 and 92 are formed of a conductive metal member, for example, aluminum or an aluminum alloy.

[0037] 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 (rectangular) shape and have a pair of opposing long sides 21a and a pair of opposing short sides 21b. In this embodiment, the four energy storage elements 20 are arranged in the Y-axis direction with the long sides 21a facing in the Y-axis direction.

[0038] 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. The energy storage element 20 may also be a battery that uses a solid electrolyte.

[0039] Specifically, the energy storage element 20 includes a metal container 21, and a pair of metal electrode terminals 22 (a positive electrode terminal and a negative electrode terminal) are provided on the lid portion of the container 21. The pair of electrode terminals 22 (a positive electrode terminal and a negative electrode terminal) are arranged to protrude from the lid portion of the container 21 toward the lid body 11 (upward, i.e., toward the positive side in the Z-axis direction). Inside the container 21, electrodes (also referred to as electricity storage elements or power generation elements), current collectors (a positive electrode current collector and a negative electrode current collector), etc. are arranged, and an electrolyte solution (a non-aqueous electrolyte) etc. is sealed inside, but a detailed description thereof will be omitted.

[0040] The four energy storage elements 20 included in the energy storage element unit 25 are connected in series, for example, by three bus bars (not shown). The bus bars are conductive members made of metal, such as copper, copper alloy, aluminum, or aluminum alloy. There are no particular limitations on the manner in which the four energy storage elements 20 are electrically connected, and two sets of energy storage element groups may be formed by connecting two energy storage elements 20 in parallel, and the two sets of energy storage element groups may be connected in series.

[0041] In the energy storage device 1 configured as described above, a reinforcing member 40 is disposed on the exterior body 10. The reinforcing member 40 is a member made of a high-strength material such as iron, and has the function of increasing the impact resistance, etc., of the energy storage device 1. In this embodiment, as shown in FIG. 2, the reinforcing member 40 is disposed along the bottom wall portion 32 of the exterior body 10, and is fixed to the exterior body 10 by four bolts 80. Details of the reinforcing member 40 according to this embodiment will be described below with reference to FIGS. 3 to 6.

[0042] [2. Reinforcement member and its surrounding structure] Fig. 3 is a perspective view showing the inside of the exterior body 10 according to the embodiment. In Fig. 3, the exterior body main body 30 is cut along the YZ plane passing through the line II-II in Fig. 2, and the energy storage device 1 is illustrated in a state in which the energy storage element unit 25 is lifted up, and the lid 11 is not illustrated. Fig. 4 is a perspective view of the energy storage device 1 according to the embodiment when viewed obliquely from below. In Fig. 4, the reinforcing member 40 is illustrated removed from the bottom wall portion 32 of the exterior body 10, and the approximate boundary between the reinforcing main body portion 45 and the protrusion portion 46 is illustrated by a dotted line.

[0043] FIG. 5 is a bottom view showing the positional and sizing relationship between the reinforcing member 40 and the energy storage element unit 25 according to the embodiment. In FIG. 5, the exterior body 10 is not shown, and the outline of the energy storage element unit 25 (four energy storage elements 20) is shown by dotted lines as seen through the reinforcing member 40. Each of the four energy storage elements 20 is represented by a dotted area to make it easy to distinguish from other elements, and the approximate boundary between the reinforcing main body portion 45 and the protrusion portion 46 is shown by a two-dot chain line. FIG. 6 is a cross-sectional view of a fixing location of the reinforcing member 40 in the exterior body 10 according to the embodiment. In FIG. 6, a cross section of a portion of the energy storage device 1 in the YZ plane passing through line VI-VI in FIG. 3 is shown, and the mounting portion 33 on which the energy storage elements 20 are mounted is not shown.

[0044] 3 to 6, the energy storage device 1 includes a reinforcing member 40 arranged along the wall of the exterior body 10. In the present embodiment, the reinforcing member 40 is arranged along the outer surface 32a of the bottom wall 32 of the exterior body 10. "The reinforcing member is arranged along the wall" means that the reinforcing member is arranged parallel to the wall and inside (between the inner surface and outer surface) or in the vicinity of the wall, and also includes the case where the reinforcing member is spaced apart from the wall by approximately several millimeters.

[0045] Specifically, as shown in Figures 4 and 6, the bottom wall 32 of the exterior body 30 is provided with four through holes 32b penetrating the bottom wall 32, and a bolt 80 is disposed in each of the four through holes 32b. The reinforcing member 40 has four mounting holes 41 at positions corresponding to the four through holes 32b, and shanks 81 of the bolts 80 are screwed into each of the four mounting holes 41. This fixes the reinforcing member 40 to the exterior body 10. The energy storage device 1 provided with the reinforcing member 40 is installed on an installation surface 200 (see Figure 6) with the reinforcing member 40 facing the installation surface 200.

[0046] More specifically, a gasket 85 is fitted into each of the four through holes 32b, and when the shank 81 of the bolt 80 is threaded into the mounting hole 41 of the reinforcing member 40, the head 82 of the bolt 80 compresses the gasket 85 in the axial direction. As a result, airtightness is maintained in the through hole 32b. Furthermore, the head 82 of the penetrating member 80 and the gasket 85, which are exposed inside the exterior body 10, may be covered and solidified with an adhesive or the like. This further improves the airtightness of the through hole 32b in the exterior body 10. The bolt 80 is a member made of a metal such as iron, aluminum, or stainless steel, and has relatively high electrical and thermal conductivity. In this embodiment, the mounting hole 41 is an open-headed hole that penetrates the reinforcing member 40, but the mounting hole 41 may also be a blind hole that does not penetrate the reinforcing member 40.

[0047] As shown in FIG. 3 , the bottom wall 32 of the exterior housing 10 has a mounting portion 33 on which the energy storage element unit 25 is placed. The mounting portion 33 is provided as a portion of the bottom wall 32 that protrudes inward from the exterior housing 10, and a recess 33a corresponding to the shape and size of the mounting portion 33 is formed on the outer surface 32a of the bottom wall 32. By placing the energy storage element unit 25 on the mounting portion 33, which is provided in the center of the bottom wall 32 in a top view, interference between the energy storage element unit 25 and the heads 82 of the bolts 80 arranged at the four corners of the bottom wall 32 is avoided. In other words, each of the four bolts 80 can be arranged at a position overlapping the energy storage element unit 25 in a top view, and the metal bolts 80 can be spaced apart from the energy storage element unit 25. A plurality of ribs 35 are arranged inside the recess 33a formed on the back side of the mounting portion 33, thereby improving the mechanical strength of the mounting portion 33. As a result, it is possible to stably or reliably support the energy storage element unit 25 fixed to the mounting portion 33. There are no particular limitations on the method for fixing the energy storage element unit 25 to the mounting portion 33, but for example, the bottom surface of the energy storage element unit 25 is adhered to the mounting portion 33 with an adhesive.

[0048] As described above, the energy storage device 1 according to this embodiment includes an energy storage element unit 25 configured with a plurality of energy storage elements 20 arranged in a first direction (Y-axis direction), an exterior body 10 that houses the energy storage element unit 25 therein, and a reinforcing member 40 fixed to the exterior body 10. The exterior body 10 has external electrode terminals 91 and 92 on its outer surface that are electrically connected to the energy storage element unit 25. The reinforcing member 40 is arranged along a bottom wall portion 32 that is a wall portion that separates the interior and exterior of the exterior body 10.

[0049] 4 to 6, the reinforcing member 40 arranged in this manner includes a reinforcing main body portion 45 and a protruding portion 46. The reinforcing main body portion 45 is a plate-shaped portion formed to a size that covers the energy storage element unit 25 when the reinforcing member 40 is viewed from the second direction (Z-axis direction) that is the alignment direction of the bottom wall portion 32 and the reinforcing member 40. The protruding portion 46 is a portion that protrudes outward beyond the energy storage element unit 25 when the reinforcing member 40 is viewed from the second direction (Z-axis direction).

[0050] As described above, in the present embodiment, the reinforcing member 40 disposed on the exterior body 10 of the energy storage device 1 has a protruding portion 46 that protrudes (extends outward) from the energy storage element unit 25 when viewed from the side of the energy storage element unit 25. Therefore, if an object collides with the energy storage device 1 from the protruding direction of the protruding portion 46, the protruding portion 46 can receive the impact before the energy storage element unit 25 receives the impact. The reinforcing member 40 further has a plate-shaped reinforcing main body portion 45 inside the protruding portion 46, so that the reinforcing main body portion 45 can absorb the impact in a direction perpendicular to the plate thickness direction. This allows efficient protection of the entire plurality of energy storage elements 20 included in the energy storage element unit 25. Not only the energy storage element unit 25, but also the bus bars, control circuit, and the like located inside the reinforcing member 40 when viewed from the second direction (Z-axis direction) can be protected by the reinforcing member 40 when the energy storage device 1 receives an impact. Thus, the energy storage device 1 according to this embodiment is an energy storage device with improved safety.

[0051] According to the above configuration, it is possible to manufacture a plurality of exterior bodies 10 of a predetermined shape and size, and to fix reinforcing members of different sizes or shapes to each of the plurality of exterior bodies 10, or to fix no reinforcing member to each of the plurality of exterior bodies 10. In this case, by accommodating a common energy storage element unit, for example, an energy storage element unit having a plurality of energy storage elements 20 restrained by a restraining member, in each of the plurality of exterior bodies 10, it is possible to obtain a plurality of types of energy storage devices 1 with different specifications for the reinforcing member. In other words, it is easy to manufacture a plurality of energy storage devices 1 that meet a plurality of requirements.

[0052] In the present embodiment, it is possible to integrate a reinforcing member into the bottom wall portion 32 by insert molding, which will be described later, but it is also possible to later fix the reinforcing member to the molded exterior body 10. Insert molding can sometimes increase costs incurred in the manufacturing process, and fixing the reinforcing member to the molded exterior body 10 later can sometimes reduce the manufacturing costs of the energy storage device 1.

[0053] In the present embodiment, protrusions 46 of reinforcing member 40 protrude outward beyond energy storage element units 25 in a first direction (Y-axis direction) that is the direction in which the plurality of energy storage elements 20 are arranged.

[0054] 3, in the energy storage element unit 25, four energy storage elements 20 are arranged in the Y-axis direction with their long side surfaces 21a facing the Y-axis direction. In the energy storage element unit 25 configured in this manner, the protrusion 46 is arranged to protrude outward from the energy storage element unit 25 in the Y-axis direction. This protects the long side surfaces 21a, which are weak parts of the energy storage elements 20, from impact. This improves the safety of the energy storage device 1.

[0055] In the present embodiment, the protrusions 46 are arranged to protrude outward from the energy storage element unit 25 also in the X-axis direction orthogonal to the first direction (Y-axis direction), i.e., in the opposing direction of the short side surfaces 21b of the four energy storage elements 20. This allows the reinforcing member 40 to collectively protect the four energy storage elements 20 included in the energy storage element unit 25 from external impact.

[0056] In exterior body 10 according to the present embodiment, the wall portion on which reinforcing member 40 is arranged is bottom wall portion 32 on the inner surface of which energy storage element unit 25 is placed.

[0057] In this embodiment, the reinforcing member 40 is made of a high-strength metal such as iron. In this case, for example, when the energy storage device 1 is deformed due to a collision accident, the reinforcing member 40 may come into contact with a conductive member inside the exterior body 10, resulting in electrical conduction. However, in this embodiment, the reinforcing member 40 is disposed on the bottom wall portion 32 on the inner surface of which the energy storage element unit 25 is placed. Therefore, problems with electrical conduction between the reinforcing member 40 and a bus bar or the like electrically connected to the energy storage element unit 25 are unlikely to occur. This is advantageous in improving the safety of the energy storage device 1.

[0058] In the present embodiment, the reinforcing member 40 is disposed within the outer edge of the exterior body 10 when viewed from the second direction (Z-axis direction). Specifically, in the present embodiment, the exterior body main body 30 has an outer edge portion 36 provided on the outer periphery of the bottom wall portion 32, as shown in Fig. 6, and the reinforcing member 40 is disposed inside the outer edge portion 36. In other words, the reinforcing member 40 according to the present embodiment is disposed in the exterior body 10 in a state in which it protrudes beyond the energy storage element unit 25 but does not protrude from the exterior body 10 when viewed from the second direction (Z-axis direction).

[0059] In this manner, in the present embodiment, the reinforcing member 40 is provided in a manner that suppresses an increase in the overall size of the exterior body 10. Therefore, if the exterior body 10 is formed to a size that complies with some standard, the reinforcing member 40 can be contained within that size. Therefore, an energy storage device 1 with improved practicality and safety can be obtained.

[0060] The reinforcing member 40 may have a portion that protrudes outward from the outer edge of the exterior body 10 when viewed from the second direction (Z-axis direction). The protruding portion 46 may be provided along the outer surface of the side wall portion 31, which is another wall portion adjacent to the bottom wall portion 32. In this case, the reinforcing member 40 has a reinforcing main body portion 45 that fits along the bottom wall portion 32 and the protruding portion 46 that fits along the side wall portion 31, and therefore has a peripheral portion that is formed with an L-shaped cross section, for example. This improves the strength of the reinforcing member 40, thereby improving the safety of the energy storage device 1. Another example of a reinforcing member having a peripheral portion with an L-shaped cross section will be described later as Modification 1.

[0061] In this embodiment, the reinforcing member 40 is disposed along the outer surface 32 a of the bottom wall portion 32 .

[0062] According to this configuration, the reinforcing member 40 can be placed without consuming the internal volume of the exterior body 10. There is also little risk of problems with electrical continuity between the metallic reinforcing member 40 and the energy storage element unit 25. When a configuration in which bolts are inserted from the outside is used to fasten the reinforcing member 40 to the exterior body 10, it is also possible to attach the reinforcing member 40 to the finished product as the energy storage device 1. This makes it possible to select a reinforcing member 40 of a shape or size that suits the placement position or placement environment of the energy storage device 1 and place it in the exterior body 10. Therefore, an energy storage device 1 with improved practicality and safety can be obtained.

[0063] The energy storage device 1 according to the embodiment has been described above, but the configuration of the reinforcing member disposed in the exterior body 10 may be different from the configurations shown in Figures 2 to 6. Therefore, the following describes energy storage devices including reinforcing members having configurations different from those of the above embodiment as Modifications 1 and 2, focusing on the differences from the above embodiment.

[0064] (Variation 1) Fig. 7 is a perspective view showing the configuration of an energy storage device 1a according to a first modified example of the embodiment. In Fig. 7, reinforcing members 60 and 70 included in the energy storage device 1a are shown removed from the exterior body 10. Fig. 8 is a diagram showing the cross-sectional shape of the reinforcing member 60 according to the first modified example of the embodiment. Fig. 8 shows a cross section of a portion of the energy storage device 1a in an XZ plane passing through line VIII-VIII in Fig. 7.

[0065] The energy storage device 1a according to this modification includes an exterior body 10, and an energy storage element unit 25 (see FIG. 2, for example) is housed inside the exterior body 10. The exterior body 10 includes external electrode terminals 91 and 92 arranged on the outer surface. In these respects, the energy storage device 1a according to this modification is common to the energy storage device 1 according to the embodiment.

[0066] In this modification, reinforcing members 60 and 70 are attached to the exterior body 10, and the reinforcing members 60 and 70 have protrusions with features different from the protrusion 46 according to the embodiment. Specifically, the reinforcing member 60 is arranged along the upper wall 12, which is a wall that separates the inside and outside of the exterior body 10, and has a protrusion 66 that protrudes outward beyond the energy storage element unit 25 when viewed from the second direction (Z-axis direction). The protrusion 66 is arranged along the outer surface of another wall (upper wall 13 in this modification) adjacent to the upper wall 12. The upper wall 13 is a wall that forms the side surface of the lid 11.

[0067] More specifically, the reinforcing member 60 has a reinforcing main body portion 65 arranged along the upper wall portion 12, and a protrusion portion 66 arranged along the upper wall portion 13 adjacent to the upper wall portion 12. In this modification, the reinforcing main body portion 65 is formed in a ring shape along the periphery of the upper wall portion 12, and therefore, with the reinforcing member 60 attached to the exterior body 10, it is possible to attach and detach cables to and from the external electrode terminals 91 and 92, and the like.

[0068] As shown in FIG. 8, the reinforcing member 60 configured in this manner has an L-shaped cross section perpendicular to the extension direction. Therefore, the strength is improved compared to when the protruding portion 66 is not provided. Specifically, the reinforcing main body portion 65 of the reinforcing member 60 has a portion that protrudes beyond the energy storage element unit 25 when viewed from the second direction (Z-axis direction) in which the upper wall portion 12 and the reinforcing member 60 are aligned. Therefore, when an impact is applied to the energy storage device 1a from the side, this protruding portion can receive the impact before the energy storage element unit 25. However, as shown in FIG. 7, the reinforcing main body portion 65 according to this modification is formed in an annular shape with an opening in the center, and is therefore weaker against a force in a direction perpendicular to the thickness direction (a direction parallel to the XY plane) than the plate-shaped reinforcing main body portion 45 without an opening (see FIG. 4). Therefore, in this modification, a protrusion 66 extending in a direction intersecting the reinforcing main body portion 65 is provided on the outer periphery of the reinforcing main body portion 65, thereby improving the strength of the reinforcing member 60 and, as a result, improving the effectiveness of the reinforcing member 60 as a member for improving the safety of the energy storage device 1a. The protrusion 66 is not only a portion erected downward from the periphery of the reinforcing main body portion 65, but may also include a portion of the reinforcing main body portion 65 that protrudes (protrudes) beyond the energy storage element unit 25 when viewed from the second direction (Z-axis direction).

[0069] The energy storage device 1a according to this modification further includes a reinforcing member 70 arranged along the bottom wall 32 of the exterior body 10. The reinforcing member 70 is arranged along the bottom wall 32, which is a wall that separates the inside and outside of the exterior body 10, and has a protruding portion 76 that protrudes outward beyond the energy storage element unit 25 when viewed from the second direction (Z-axis direction). The protruding portion 76 is arranged along the outer surface of another wall portion (the side wall portion 31 in this modification) adjacent to the bottom wall portion 32. Specifically, the reinforcing member 70 has a reinforcing main body portion 75 that faces the bottom wall portion 32, and the protruding portion 76 stands upright from the periphery of the reinforcing main body portion 75. In other words, like the reinforcing member 60, the reinforcing member 70 also has a portion with an L-shaped cross section on the outer periphery, which improves the strength of the reinforcing member 70.

[0070] As described above, each of the reinforcing members 60 and 70 has a peripheral edge portion formed with an L-shaped cross section, which improves strength and allows the reinforcing members 60 and 70 to be attached so as to cover the outer periphery of the bottom wall portion 32 or the top wall portion 12. In other words, the reinforcing members 60 and 70 can be easily attached to the exterior body 10 later, thereby improving the safety of the energy storage device 1a. Each of the reinforcing members 60 and 70 may be fixed to the exterior body 10 with an adhesive or screws, but fixing to the exterior body 10 is not essential. In other words, each of the reinforcing members 60 and 70 may be attached to the exterior body 10 with an engagement force that does not easily detach.

[0071] (Variation 2) Fig. 9 is a perspective view showing the configuration of an energy storage device 1b according to a second modification of the embodiment. In Fig. 9, a reinforcing member 140 included in the energy storage device 1b is shown removed from the exterior body 10, and the energy storage element unit 25 and the lid body 11 are not shown. Fig. 10 is a diagram showing a cross-sectional shape of the reinforcing member 140 according to the second modification of the embodiment. Fig. 10 shows a cross section of a portion of the energy storage device 1b in an XZ plane passing through the XX line in Fig. 9.

[0072] The energy storage device 1b according to this modification includes an exterior body 10 that houses an energy storage element unit 25. A reinforcing member 140 is fixed to the exterior body 10 and is arranged along a bottom wall portion 32 of the exterior body 10. When viewed from a second direction (Z-axis direction) that is the alignment direction of the bottom wall portion 32 and the reinforcing member 140, the reinforcing member 140 includes a plate-shaped reinforcing main body portion 145 formed to a size that covers the energy storage element unit 25, and a protrusion portion 146 that protrudes outward beyond the energy storage element unit 25. In this configuration, the reinforcing member 140 according to this modification and the reinforcing member 40 according to the embodiment are common.

[0073] 9 and 10, the reinforcing member 140 has a flat plate portion 142 that abuts against the installation surface 200, and a connecting portion 143 that is fixed to the flat plate portion 142 and connected to the bolt 80. The flat plate portion 142 and the connecting portion 143 are joined by welding, for example.

[0074] According to this configuration, for example, a relatively thin metal plate can be used as the flat plate portion 142, and the connecting portion 143, which has the mounting hole 141 suitable for connection to the bolt 80, can be fabricated as a separate member from the flat plate portion 142. Therefore, the flat plate portion 142 and the connecting portion 143 can be fabricated from different materials. As shown in FIG. 10 , the tip of the shaft portion 81 of the bolt 80 can protrude downward from the connecting portion 143, so the connecting portion 143 can be fabricated from a relatively thin plate material. In other words, the entire reinforcing member 140 can be fabricated from a relatively thin plate material. It is also possible to fabricate multiple types of reinforcing members with different sizes or shapes of flat plate portions using the connecting portion 143 as a common component. Therefore, the reinforcing member 140 according to this modification can improve the safety of the power storage device 1b and has a high degree of freedom in the materials used for fabrication.

[0075] The connecting portion 143 may be formed so that the portion of the mounting hole 141 that is connected to the bolt 80 is thicker than the other portions. Specifically, the connecting portion 143 may have a nut welded to a bent, plate-shaped connecting portion main body, thereby providing the mounting hole 141 that is connected to the bolt 80. This makes it possible to improve the bonding strength between the connecting portion 143 and the bolt 80 compared to when the mounting hole 141 is provided in the relatively thin connecting portion main body itself.

[0076] In this modified example, a gap is formed between a part of the reinforcing member 140 other than the part connected to the bolt 80 and the outer surface 32a of the bottom wall portion 32 of the outer casing 10 that faces the reinforcing member 140.

[0077] 10 , in the reinforcing member 140, the connecting portion 143 connected to the bolt 80 has a bent shape so as to separate the mounting hole 141 from the flat plate portion 142. As a result, the reinforcing member 140 is fixed to the exterior body 10 with the flat plate portion 142 floating above the outer surface 32a of the bottom wall portion 32. As a result, a clear gap is formed between the flat plate portion 142 and the outer surface 32a of the bottom wall portion 32.

[0078] According to this configuration, the gap between the flat plate portion 142 and the bottom wall portion 32 can be used as a space for bending of the flat plate portion 142 in the thickness direction (Z-axis direction). When an impact is applied to the power storage device 1b from below, the flat plate portion 142 bends (deforms) so as to approach the bottom wall portion 32, thereby suppressing transmission of the impact to the exterior body 10. The gap between the flat plate portion 142 and the bottom wall portion 32 serves as a flow path for a fluid such as air that exchanges heat with the power storage device 1b, thereby improving the heat dissipation efficiency of the power storage device 1b.

[0079] (Other embodiments) 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.

[0080] For example, the material of the reinforcing member 40 does not have to be a metal such as iron. The reinforcing member 40 may be made of a resin that is stronger than the material that forms the exterior body 10. This allows the reinforcing member 40 to be made lighter.

[0081] The wall on which the reinforcing member is arranged is not limited to the bottom wall 32, and the reinforcing member may be arranged along the top wall 12 or the side wall 31. In either case, the reinforcing member has a plate-shaped reinforcing main body sized to cover the energy storage element unit 25 and a protrusion that protrudes outward beyond the energy storage element unit 25, thereby achieving the effect of shock absorption or reduction by the reinforcing member. When the reinforcing member is arranged along one of a pair of side wall portions 31 (see FIG. 2 ) that face each other in the Y-axis direction of the exterior body 10, the arrangement direction (first direction) of the multiple energy storage elements 20 coincides with the arrangement direction (second direction) of the reinforcing member and the wall portion.

[0082] The reinforcing member may be disposed inside the wall (between the outer surface and the inner surface). For example, a reinforcing member integrated with the bottom wall 32 by insert molding may be disposed in the exterior body 10. Alternatively, the reinforcing member may be sandwiched between two layers of a wall divided in the thickness direction. In either case, bolts 80 for fastening the reinforcing member to the exterior body 10 are not required, thereby reducing the number of components or the weight of the energy storage device 1. The reinforcing member may be disposed inside the wall (inside the exterior body 10). For example, the reinforcing member may be disposed between the bottom wall 32 and the energy storage element unit 25. In this case, the reinforcing member and the energy storage element unit 25 can be electrically insulated by disposing an insulating sheet or the like between the reinforcing member and the energy storage element unit 25. Furthermore, the reinforcing member disposed inside the exterior body 10 can be fixed by the bolt 80 by inserting the bolt 80 into the through-hole 32b from the outer surface 32a side of the bottom wall 32.

[0083] The plate-shaped reinforcing main body portion 45 of the reinforcing member 40 does not need to completely cover the energy storage element unit 25 without any gaps when viewed from the arrangement direction (second direction) of the wall portion on which it is placed and the energy storage element unit. For example, the reinforcing main body portion 45 may have an opening (through hole) for fixing the reinforcing member 40 to the installation surface 200 within an area overlapping with the energy storage element unit 25. The reinforcing main body portion 45 may have a plurality of openings (through holes) dispersedly arranged to reduce weight. In other words, the reinforcing main body portion 45 may be provided with openings, through holes, thin-walled portions, or the like to an extent that the function of absorbing the impact received by the protrusion 46 is not lost more than necessary.

[0084] The reinforcing member 40 does not need to have both surfaces in the thickness direction flat, and at least one of the surfaces may have a bent portion or a rib or the like formed thereon to improve strength.

[0085] The various supplementary points regarding the reinforcing member 40 described above may also be applied to the reinforcing members 60, 70, and 140 according to the first and second modifications.

[0086] The energy storage element unit 25 may include elements other than the energy storage elements 20, such as spacers arranged along each of the multiple energy storage elements 20 and / or a bus bar connected to at least one of the energy storage elements 20. Each of the multiple energy storage elements 20 may have an insulating film covering the outer periphery.

[0087] Any combination of the above-described components is also included within the scope of the present invention. [Industrial Applicability]

[0088] 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]

[0089] 1, 1a, 1b Energy storage device 10. Exterior body 11 Lid 12 Upper wall 13 Upper wall 20 Energy storage element 25 Energy storage element unit 30 Exterior body 31 Side wall 32 Bottom wall 32a Exterior 36 outer edge 40, 60, 70, 140 Reinforcement member 41, 141 mounting holes 45, 65, 75, 145 Reinforced body 46, 66, 76, 146 protrusion 80 volts 91, 92 External electrode terminals 200 Installation surface

Claims

1. a storage element unit including a plurality of storage elements arranged in the first direction with their long sides facing the first direction; an exterior housing that houses the energy storage element unit therein and has external electrode terminals on its outer surface that are electrically connected to the energy storage element unit; a reinforcing member disposed near a wall portion that separates the inside and outside of the exterior body and fixed to the exterior body; the reinforcing member includes a plate-shaped reinforcing main body portion formed to a size sufficient to cover the energy storage element unit when viewed from a second direction that is an arrangement direction of the wall portion and the reinforcing member and that intersects with the first direction, and a protrusion portion that protrudes outward beyond the energy storage element unit; the reinforcing member does not have a portion that protrudes from the exterior body when viewed from the second direction, In the exterior housing, the wall portion is a bottom wall portion on an inner surface of which the energy storage element unit is placed. Energy storage device.

2. the protruding portion protrudes outward beyond the energy storage element unit in the first direction; The electricity storage device according to claim 1.

3. The reinforcing member is disposed near the outer surface of the wall portion. The electricity storage device according to claim 1 or 2.

4. The exterior body is formed of resin, The reinforcing member is made of metal. The electricity storage device according to any one of claims 1 to 3.

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