Power storage device

Abstract

To provide a power storage device that is equipped with a sheath, has a simple structure, and is improved in reliability.SOLUTION: A power storage device 1 is equipped with a sheath 10 that stores a power storage element 20. The sheath 10 has a sheath body 110, and a lid body 120 joined with the sheath body 110. The sheath body 110 has a first wall portion 115 raised along a first direction that is an attaching direction of one of the lid body 120 and the sheath body 110 to the other. The lid body 120 has a groove portion 127 in which the first wall portion 115 is inserted in the first direction, and which is joined with the first wall portion 115 by an adhesive 180. On an opposite surface where one of the first wall portion 115 and the groove portion 127 opposes to the other in a second direction that is a thickness direction of the first wall portion 115, a storage portion 116 for storing the adhesive 180 is provided, which is formed in a recessed shape in a Y-axis direction from the opposite surface.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an electricity storage device including an exterior body. [Background technology]

[0002] Patent Document 1 discloses an electricity storage device including a housing (exterior body). The exterior body has a first member having an opening and a second member, and the first and second members are joined at a joint provided on the periphery of the opening. The joint has a circumferential groove provided on one of the first and second members, a convex edge provided on the other, and an adhesive layer. The tip of the convex edge is positioned in the circumferential groove and is adhered to the inner wall of the circumferential groove by the adhesive layer. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2017 / 115404 Summary of the Invention [Problem to be solved by the invention]

[0004] The exterior of an energy storage device generally has a joint (a joint portion) where two components, such as a main body and a lid, are joined. For example, in the joint portion of the exterior of the conventional energy storage device described above, a convex portion of one of the two components is inserted into a groove of the other component, and the convex portion is fixed to the groove with an adhesive. The joint portion formed in this manner significantly affects, for example, the airtightness, watertightness, or strength of the exterior. Therefore, to improve the reliability of the energy storage device, high joint strength is required. To this end, the conventional energy storage device described above employs a structure in which a claw provided on the convex portion is inserted into a socket formed on the inner surface of the groove. However, this structure has the problem of complex shapes of the convex portion and the groove, and also requires high precision in the position and shape of the claw and the socket. Therefore, increasing the amount of adhesive can be considered to improve the strength of the joint, but this raises the problem of the adhesive easily overflowing from the groove. If the adhesive overflows from the groove, a process of wiping off the adhesive is required to prevent the energy storage device from being deemed a defective product. Furthermore, in order to prevent the adhesive from overflowing, it is necessary to strictly manage and control the amount of adhesive, which makes the manufacturing process of the electricity storage device more complicated.

[0005] The present invention was made by the inventor of the present application by focusing on the above-mentioned problem, and aims to provide an energy storage device having an exterior body, which has a simple configuration and improved reliability. [Means for solving the problem]

[0006] One aspect of the present invention provides an energy storage device that includes an outer casing that houses an energy storage element, wherein the outer casing includes a first member and a second member joined to the first member, the first member having a wall portion that stands along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member having a groove portion into which the wall portion is inserted in the first direction and joined to the wall portion with an adhesive, and a storage portion for storing the adhesive is provided on an opposing surface of one of the wall portion and the groove portion that is the side that faces the other in a second direction that is the thickness direction of the wall portion, the opposing surface being recessed from the opposing surface in the second direction.

[0007] According to this configuration, the first member and the second member are joined with an adhesive while the wall portion of the first member is inserted into the groove portion of the second member. In this joining structure, at least one of the first member and the second member has a recessed accommodation portion. Therefore, the adhesion area (area in close contact with the adhesive) of the first member is larger than when the accommodation portion is not present, resulting in improved joint strength between the first member and the second member. Furthermore, even when a relatively large amount of adhesive is poured into the groove and the wall portion is inserted into the groove, the accommodation portion prevents the adhesive from overflowing from the groove. Therefore, for example, the joint strength between the first member and the second member can be improved with a relatively large amount of adhesive, without the need for strict control of the amount of adhesive or wiping off overflowing adhesive. As such, the energy storage device according to this aspect is an energy storage device with a simple configuration and improved reliability.

[0008] The storage portion may be one of a plurality of inner surfaces that form a storage space for the adhesive, and may have an inner surface that faces the direction of removal of one of the wall portion and groove portion in which the storage portion is provided from the other, and the adhesive may be stored in the storage portion while being in close contact with the inner surface.

[0009] According to this configuration, a portion of the solidified adhesive in the groove is contained in the container, and this portion is in close contact with one of the inner surfaces of the container, which is the inner surface of one of the wall portion having the container and the groove portion facing the direction of removal from the other. In other words, for example, if the wall portion has a container, when attempting to remove the wall portion from the groove, the portion of the solidified adhesive contained in the container functions as a movement restriction for the wall portion in the removal (removal) direction. This further improves the bonding strength between the first member and the second member by the adhesive.

[0010] The first member and the second member may be members that separate the inside and outside of the outer casing, and the storage portion may be provided on the opposing surface of the wall portion that faces the outside of the outer casing, or on the opposing surface of the groove portion that is located closer to the outside of the outer casing than the wall portion.

[0011] With this configuration, when the wall portion is inserted into the groove, the adhesive that is pushed out by the wall portion in the groove and moves to the outside of the exterior body can be contained in the containing portion located in the direction of the movement, thereby more reliably preventing the adhesive from spilling out to the outside of the exterior body.

[0012] The housing portions may be arranged in a plurality in the first direction on the opposing surfaces of the one of the wall portion and the groove portion.

[0013] According to this configuration, the recessed accommodating portions are arranged in a row in the mounting direction (first direction) on the opposing surface, forming an uneven shape on the opposing surface. Therefore, the adhesive solidifies in a state of being in close contact with the uneven shape, further improving the bonding strength between the first member and the second member by the adhesive.

[0014] The wall portion may have an inclined surface provided at the tip of the wall portion in the direction of insertion into the groove portion, and the inclined surface may be inclined so as to move away from the inner bottom surface of the groove portion as it moves from one end of the wall portion in the second direction to the other end.

[0015] A storage device according to one aspect of the present invention is a storage device including an outer casing that houses a storage element, wherein the outer casing has a first member and a second member joined to the first member, the first member having a wall portion erected along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member having a groove portion into which the wall portion is inserted in the first direction and joined to the wall portion with an adhesive, the wall portion having an inclined surface provided at a tip portion of the wall portion in the insertion direction into the groove portion, and the inclined surface being inclined so as to move away from an inner bottom surface of the groove portion as it moves from one end of the wall portion to the other end in a second direction that is a thickness direction of the wall portion.

[0016] These configurations with inclined surfaces allow the inclined surfaces to control the main direction of movement of the adhesive that is pushed out by the wall and moves within the groove when the wall is inserted into the groove. For example, consider a case where it is desired to prevent the adhesive from spilling out in one direction in the thickness direction (second direction) of the wall. In this case, an inclined surface is formed at the tip of the wall, inclined so as to move away from the inner bottom surface of the groove as it moves from one side in the thickness direction to the other. In this case, the inclined surface primarily pushes the adhesive to the other side. As a result, spilling of the adhesive from the joint between the first and second members to the one side is more reliably suppressed.

[0017] A storage device according to one aspect of the present invention is a storage device including an outer casing that houses a storage element, wherein the outer casing has a first member and a second member joined to the first member, the first member has a wall portion that stands along a first direction that is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove portion into which the wall portion is inserted in the first direction and joined to the wall portion with an adhesive, and the wall portion is provided with a storage portion for accommodating the adhesive, the storage portion being formed in a notched shape from a tip portion facing an inner bottom surface of the groove portion.

[0018] According to this configuration, the first member and the second member are joined with an adhesive while the wall portion of the first member is inserted into the groove portion of the second member. In this joining structure, the wall portion of the first member is provided with a notched accommodation portion extending from the tip. Therefore, the adhesive area (area in close contact with the adhesive) of the wall portion is increased compared to when the accommodation portion is not provided, thereby improving the joining strength between the first member and the second member. Furthermore, even when a relatively large amount of adhesive is poured into the groove and the wall portion is inserted into the groove, the accommodation portion prevents the adhesive from spilling out of the groove. Therefore, for example, the joining strength between the first member and the second member can be improved with a relatively large amount of adhesive, and strict control of the amount of adhesive and wiping off spilled adhesive are not required. Thus, the energy storage device according to this aspect is a simple configuration with improved reliability. [Effects of the Invention]

[0019] According to the present invention, it is possible to provide an electricity storage device that includes an exterior body and has a simple configuration and improved reliability. [Brief explanation of the drawings]

[0020] [Figure 1] 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. 2 is a perspective view of an exterior body according to an embodiment. [Figure 4] FIG. 2 is a perspective cross-sectional view of a lid according to the embodiment. [Figure 5] 1 is a perspective cross-sectional view showing the structural relationship between an exterior body and a lid according to an embodiment. FIG. [Figure 6] 1 is a perspective cross-sectional view showing a state in which an exterior body and a lid according to an embodiment are combined together. FIG. [Figure 7] 10 is a perspective cross-sectional view showing a joining portion between an exterior body and a lid in an exterior body according to a first modified example of the embodiment. FIG. [Figure 8]FIG. 10 is a perspective view of an exterior body according to a second modification of the embodiment. [Figure 9] 10 is a perspective cross-sectional view showing a joining portion between an exterior body and a lid in an exterior body according to a second modification of the embodiment. FIG. [Figure 10] FIG. 11 is a perspective view of an exterior body according to a third modified example of the embodiment. [Figure 11] 11 is a perspective cross-sectional view showing a joining portion between an exterior body and a lid in an exterior body according to a third modification of the embodiment. FIG. [Figure 12] 10 is a perspective cross-sectional view showing a joining portion between an exterior body and a lid in an exterior body according to a fourth modification of the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0021] 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). Note that the embodiments described below all show comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection configurations, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are merely examples and are not intended to limit the present invention. Furthermore, in each drawing, dimensions and the like are not strictly illustrated. Furthermore, in each drawing, the same or similar components are assigned the same reference numerals.

[0022] In the following description and drawings, the longitudinal direction of the exterior body of the energy storage device, or the direction in which the short sides of the energy storage elements face each other, is defined as the X-axis direction. The lateral direction of the exterior body of the energy storage device, or the arrangement direction of multiple energy storage elements, is defined as the Y-axis direction. The arrangement direction of the main body and lid of the exterior body of the energy storage device, or the up-down direction, is defined as the Z-axis direction. These X-axis, Y-axis, and Z-axis directions intersect each other (orthogonal in this embodiment). Note that depending on the mode of use, the Z-axis 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.

[0023] In the following description, for example, the positive X-axis direction refers to the direction of the arrow on the X-axis, and the negative X-axis direction refers to the direction opposite to the positive X-axis direction. The same applies to the Y-axis and Z-axis. Furthermore, simply referring to the "X-axis direction" means either or both directions parallel to the X-axis. The same applies to terms related to the Y-axis and Z-axis.

[0024] Furthermore, expressions indicating relative directions or attitudes, such as parallel and perpendicular, also include cases where the directions or attitudes are not strictly those. For example, saying that two directions are perpendicular does not only mean that the two directions are completely perpendicular, but also means that the directions are substantially perpendicular, that is, that there is a difference of, for example, a few percent. Furthermore, simply saying "X-axis direction" means both directions or either direction parallel to the X-axis. The same applies to terms related to the Y-axis and Z-axis. In the following explanation, when we say "insulation," it means "electrical insulation."

[0025] (Embodiment) [1. General description of the power storage device] First, an overall description of an energy storage device 1 according to an embodiment will be given using Figures 1 and 2. Figure 1 is a perspective view showing the appearance of the energy storage device 1 according to an embodiment. Figure 2 is an exploded perspective view of the energy storage device 1 according to an embodiment. Figure 2 illustrates a state in which the cover 120 of the exterior body 10 is separated from the exterior body main body 110, exposing a plurality of energy storage elements 20 (energy storage element units 24).

[0026] The power storage device 1 is a device that can charge with electricity from an external source and discharge electricity to the outside, and in this embodiment, has a substantially rectangular parallelepiped shape. The power storage device 1 is, for example, a battery module (battery assembly) used for power storage or power supply purposes. 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, 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 fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicle. Examples of the electric railway vehicle include a train, a monorail, a linear motor car, and a hybrid train equipped with both a diesel engine and an electric motor. The power storage device 1 can also be used as a stationary battery for home or business use.

[0027] As shown in FIGS. 1 and 2, the energy storage device 1 includes energy storage elements 20 and an exterior body 10 that houses the energy storage elements 20. In this embodiment, four 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 four. The energy storage device 1 may include one or more energy storage elements 20. In this embodiment, one energy storage element unit 24 is configured by four energy storage elements 20 arranged in the Y-axis direction. The energy storage element unit 24 may include a spacer, an insulating film, etc., which are not shown.

[0028] The exterior body 10 has an exterior body main body 110 that houses the energy storage element unit 24, and a lid body 120 that closes an opening (main body opening 111) of the exterior body main body 110. In the present embodiment, the exterior body main body 110 is an example of a first member, and the lid body 120 is an example of a second member. Inside the exterior body 10, above the energy storage element unit 24, bus bars electrically connected to the multiple energy storage elements 20, a bus bar plate that holds the bus bars, a control circuit, and the like are arranged, but illustration and description of these members are omitted.

[0029] The exterior body 10 is a substantially rectangular parallelepiped (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 secures the energy storage element unit 24, the bus bar plate, 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), polyamide (PA), ABS resin, or a composite material thereof, or a metal with an insulating coating.

[0030] The exterior body 110 of the exterior body 10 is a rectangular cylindrical housing with a bottom and a body opening 111 formed therein for accommodating the energy storage element unit 24. The lid 120 is a rectangular member that closes the body opening 111 of the exterior body body 110, 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 multiple energy storage elements 20, 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.

[0031] 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 in this embodiment, four energy storage elements 20 are arranged in the Y-axis direction as described above.

[0032] The energy storage element 20 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 20 may not be a secondary battery, but 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 pouch-type energy storage element. The shape of the energy storage element 20 is not limited to the above-mentioned rectangular shape, but may be other shapes such as a polygonal prism, a cylindrical shape, an elliptical cylindrical shape, or an oblong cylindrical shape.

[0033] 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 Y-axis direction with their long sides 21a facing the Y-axis direction (with their short sides 21b parallel to the Y-axis direction).

[0034] Metallic electrode terminals 22 (positive and negative terminals) are provided on the cover plate 21c of the container 21 and are electrically connected to the electrode body inside the container 21. The electrode terminals 22 are arranged to protrude upward (in the positive direction of the Z axis) from the cover plate 21c of the container 21. The cover plate 21c of the container 21 is further provided with a gas exhaust valve 23 for exhausting internal gas to the outside when the internal pressure of the container 21 rises excessively. In this 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 in the positive direction of the Z axis.

[0035] In the energy storage device 1 having such a basic configuration, the body opening 111 of the exterior body 110 is sealed by the lid 120. Specifically, if the gas exhaust valve 23 of the energy storage element 20 opens and gas is released, for example, to ensure the safety of the user of the energy storage element 20, the gas needs to be guided to a predetermined location through an exhaust port (not shown) provided in the exterior body 10. However, if there is a gap at the joint between the exterior body 110 and the lid 120, or if a gap is created due to gas pressure, gas will leak from an unexpected location, which could cause an unsafe event. Furthermore, the energy storage device 1 may be used in situations exposed to wind and rain, or may be submerged in water due to a natural disaster, for example. Therefore, the joint between the exterior body 110 and the lid 120 may be required to be highly airtight or watertight.

[0036] Therefore, the joint between the exterior body main body 110 and the lid body 120 is an important part from the viewpoint of maintaining or improving the reliability of the energy storage device 1. On the other hand, it is difficult to adopt a complex structure for the joint or a joining method that requires complicated work from the viewpoint of time or economic efficiency in manufacturing the energy storage device 1.

[0037] Therefore, this embodiment employs a simple configuration for more reliably joining exterior body main body 110 and lid body 120. Hereinafter, the joining portion between exterior body main body 110 and lid body 120 according to this embodiment will be described in detail with reference to Figs. 3 to 6.

[0038] [2. Regarding the joint between the exterior body and the lid] FIG. 3 is a perspective view of exterior body main body 110 according to an embodiment. FIG. 3 shows an enlarged view of a portion of first wall portion 115 arranged on the periphery of main body opening 111. FIG. 4 is a perspective cross-sectional view of lid body 120 according to an embodiment. FIG. 4 shows a cross-section of lid body 120 in the YZ plane passing through line IV-IV in FIG. 2. FIG. 5 is a perspective cross-sectional view showing the structural relationship between exterior body main body 110 and lid body 120 according to an embodiment. FIG. 6 is a perspective cross-sectional view showing a state in which exterior body main body 110 and lid body 120 according to an embodiment are combined. The positions of the cross-sections in FIGS. 5 and 6 correspond to the positions of the cross-sections in FIG. 4.

[0039] As shown in the above-described FIG. 2 and FIGS. 3 to 6, the lid 120 is a member that is attached from the opening direction of the main body opening 111 of the exterior body main body 110 (the positive direction of the Z axis) toward the exterior body main body 110. The exterior body main body 110 has a first wall 115 provided on the periphery of the main body opening 111. The lid 120 has a groove 127 into which the first wall 115 of the exterior body main body 110 is inserted. Specifically, as shown in FIGS. 4 to 6, the groove 127 is formed between a pair of second walls 125 and 128 provided on the lid 120.

[0040] First wall portion 115 of exterior body main body 110 and the pair of second wall portions 125 and 128 of lid body 120 are both erected along the mounting direction (Z-axis direction) of one of lid body 120 and exterior body main body 110 relative to the other. This mounting direction (Z-axis direction) is an example of a first direction, and the thickness direction of first wall portion 115 (Y-axis direction in FIGS. 5 and 6 ), which is perpendicular to the mounting direction, is an example of a second direction.

[0041] That is, in the present embodiment, in a state where first wall portion 115 is inserted into groove portion 127 (see FIG. 6), first wall portion 115 is located between opposing surfaces 127a and 127b, which are side surfaces (inner surfaces) of groove portion 127, in the second direction. Specifically, opposing surface 115a, which is one side surface of first wall portion 115 in the second direction, faces opposing surface 127a of groove portion 127. Opposing surface 115b, which is the other side surface of first wall portion 115 in the second direction, faces opposing surface 127b of groove portion 127. That is, at the joint portion between groove portion 127 and first wall portion 115, there are two pairs of opposing surfaces (opposing surface 127a and opposing surface 115a, and opposing surface 127b and opposing surface 115b) that face each other in the second direction.

[0042] The lid 120 and the exterior body main body 110 configured in this manner are joined together with adhesive 180, as shown in FIG. 6 . For example, the lid 120 is turned upside down so that the opening of the groove 127 faces upward, and then adhesive 180 is poured into the groove 127. Furthermore, the first wall 115 of the exterior body main body 110 is inserted into the groove 127 of the lid 120 from above the groove 127 (see FIG. 5 ). The adhesive 180 then solidifies, thereby joining the lid 120 and the exterior body main body 110 together. During this joining operation, when the first wall 115 is inserted into the groove 127, the fluid adhesive 180 before solidifying may overflow from the groove 127. If the adhesive 180 overflows onto the exterior side of the exterior body 10 (the outside of the second wall 125 of the lid 120), for example, it becomes necessary to wipe off the adhesive 180 using a solvent or the like. In other words, if the overflowing adhesive 180 is left as it is, the adhesive 180 will cause defects in appearance, etc. Therefore, it is necessary to prevent the adhesive 180 from overflowing from the groove 127. Of course, the possibility of the adhesive 180 overflowing can be reduced by reducing the amount of adhesive 180 contained in the groove 127, but in this case, the bonding strength between the groove 127 and the first wall 115 will be reduced. Furthermore, strictly managing and controlling the amount of adhesive 180 contained in the groove 127 will complicate the manufacturing process of the energy storage device 1.

[0043] Therefore, exterior body 10 according to the present embodiment is provided with storage portion 116 for using a relatively large amount of adhesive 180 to join lid body 120 and exterior body main body 110, while suppressing overflow of adhesive 180 from groove portion 127. More specifically, storage portion 116 formed in a recessed shape in the second direction is disposed on at least one of two pairs of opposing surfaces that face each other in the second direction in first wall portion 115 and groove portion 127. Part of adhesive 180 poured into groove portion 127 is stored in storage portion 116, thereby suppressing overflow of adhesive 180 from groove portion 127.

[0044] As described above, the energy storage device 1 according to this embodiment includes an exterior body 10 that houses the energy storage elements 20. The exterior body 10 includes an exterior body main body 110 that is an example of a first member, and a lid body 120 that is an example of a second member and is joined to the exterior body main body 110. The exterior body main body 110 has a first wall portion 115 that is erected along a first direction (the Z-axis direction in this embodiment) that is an attachment direction of one of the lid body 120 and the exterior body main body 110 relative to the other. The lid body 120 has a groove portion 127 into which the first wall portion 115 is inserted in the Z-axis direction and joined to the first wall portion 115 with adhesive 180. One of the first wall portion 115 and the groove portion 127 has an opposing surface that is a side surface that faces the other in a second direction (the Y-axis direction in FIG. 6 ) that is the thickness direction of the first wall portion 115, and a storage portion 116 that is recessed from the opposing surface in the Y-axis direction and that stores adhesive 180 is provided. Specifically, as shown in Figures 5 and 6, the storage section 116 in this embodiment is formed in a recessed shape on the opposing surface 115a of the first wall section 115 from the opposing surface 115a in the Y-axis direction (the positive Y-axis direction in Figure 6).

[0045] According to this configuration, exterior body main body 110 and lid body 120 are joined together with adhesive 180 in a state in which first wall portion 115 of exterior body main body 110 is inserted into groove portion 127 of lid body 120. In this joining structure, at least one of exterior body main body 110 and lid body 120 is provided with accommodation portion 116 formed in a recessed shape. Therefore, the adhesion area (area in close contact with adhesive 180) of first wall portion 115 is increased compared to a case in which accommodation portion 116 is not provided, and as a result, the joining strength between exterior body main body 110 and lid body 120 is improved. Furthermore, even if first wall portion 115 is inserted into groove portion 127 with a relatively large amount of adhesive 180 poured into it, overflow of adhesive 180 from groove portion 127 is suppressed by accommodation portion 116 containing adhesive 180. Therefore, for example, the bonding strength between the exterior body main body 110 and the lid body 120 can be improved by using a relatively large amount of adhesive 180, and there is no need to strictly control the amount of adhesive 180 or to wipe off any overflowing adhesive 180. In this way, the energy storage device 1 according to this embodiment is an energy storage device with a simple configuration and improved reliability.

[0046] Furthermore, in this embodiment, the accommodation portion 116 has an inner surface 116a, which is one of a plurality of inner surfaces that form a space for accommodating the adhesive 180, and which faces the direction in which one of the first wall portion 115 and the groove portion 127, in which the accommodation portion 116 is provided, is removed from the other. Specifically, the direction in which the first wall portion 115, in which the accommodation portion 116 is provided, is removed (pulled out) from the groove portion 127 is the negative direction of the Z axis. For example, as shown in FIG. 6, the accommodation portion 116 has an inner surface 116a that faces the negative direction of the Z axis. The adhesive 180 is accommodated in the accommodation portion 116 in a state of being in close contact with the inner surface 116a.

[0047] According to this configuration, a portion of adhesive 180 solidified in groove 127 is accommodated in accommodation portion 116, and this portion is in close contact with inner surface 116a of one of first wall portion 115 having accommodation portion 116 and groove 127, which faces the direction of removal from the other. In other words, in a case where accommodation portion 116 is provided in first wall portion 115, when first wall portion 115 is to be removed from groove 127, the portion of solidified adhesive 180 accommodated in accommodation portion 116 functions as a portion that restricts movement of first wall portion 115 in the removal (removal) direction. This further improves the bonding strength between exterior body 110 and lid 120 by adhesive 180.

[0048] In the present embodiment, the first and second members of exterior body 10 are exterior body main body 110 and lid 120, that is, members that separate the inside and outside of exterior body 10. Storage section 116 is provided on opposing surface 115a of first wall portion 115 that faces the outside of exterior body 10.

[0049] According to this configuration, when first wall portion 115 is inserted into groove portion 127, adhesive 180 that is pushed out by first wall portion 115 in groove portion 127 and moves to the outside of exterior body 10 can be contained in storage portion 116 located in the direction of movement. In other words, adhesive 180 that attempts to overflow from groove portion 127 to the outside of exterior body 10 (the negative Y-axis direction in FIG. 6 ) can be efficiently contained in storage portion 116. This makes it possible to more reliably prevent adhesive 180 from overflowing to the outside of exterior body 10.

[0050] The above has described the energy storage device 1 according to the embodiment, focusing on the joint portion between the exterior body main body 110 and the lid body 120. However, the structure of the joint portion may be different from that shown in Figures 3 to 6. Therefore, below, modifications of the joint portion between the exterior body main body 110 and the lid body 120 will be described, focusing on the differences from the above embodiment.

[0051] [3-1. Variation 1] 7 is a perspective cross-sectional view showing the joint portion between exterior body main body 110 and lid body 120a in exterior body 10a according to Variation 1 of the embodiment. The positions of the cross sections in FIG. 7 and in FIGS. 9, 11, and 12 described below correspond to the positions of the cross sections in FIG. 4.

[0052] 7, exterior body 10a according to this modification has exterior body main body 110 and lid body 120a, and with first wall portion 115 of exterior body main body 110 inserted into groove portion 127 of lid body 120a, first wall portion 115 and groove portion 127 are joined together with adhesive 180. In this configuration, exterior body 10a according to this modification and exterior body 10 according to the embodiment are common.

[0053] This modification differs from the above embodiment in that a storage portion 129 is provided in groove portion 127. Specifically, groove portion 127 has a facing surface 127a that is closer to the outside of exterior body 10a than first wall portion 115, and storage portion 129 is provided in a recessed shape extending from facing surface 127a in the second direction (Y-axis direction).

[0054] In other words, when the internal space of groove 127 is divided into the interior and exterior sides of exterior body 10a by first wall 115, accommodating section 129 is located on the exterior side of exterior body 10a, similar to accommodating section 116 according to the embodiment. Therefore, according to exterior body 10a according to this modification, when first wall 115 is inserted into groove 127, adhesive 180 that is pushed out by first wall 115 in groove 127 and moves to the exterior side of exterior body 10a can be accommodated in accommodating section 129 located in the direction of movement. In other words, adhesive 180 that attempts to overflow from groove 127 to the exterior side of exterior body 10a can be efficiently accommodated in accommodating section 129. This more reliably prevents adhesive 180 from overflowing to the exterior side of exterior body 10a.

[0055] 7, in this modification, in addition to accommodating section 116 provided in first wall section 115, accommodating section 129 provided in groove section 127 (second wall section 125) is also provided at the joint between exterior body main body 110 and lid body 120a. This increases the adhesion area (area in close contact with adhesive 180) of each of exterior body main body 110 and lid body 120a at the joint, thereby improving the bonding strength between exterior body main body 110 and lid body 120a. However, it is not essential to provide two accommodating sections (accommodating sections 116 and 129) at the joint; when accommodating section 129 is provided in groove section 127, accommodating section 116 does not have to be provided in first wall section 115.

[0056] [3-2. Variation 2] Fig. 8 is a perspective view of exterior body main body 110b according to Modification 2 of the embodiment. Fig. 8 shows an enlarged view of a portion of first wall portion 115 arranged on the periphery of main body opening 111. Fig. 9 is a perspective cross-sectional view showing a joining portion between exterior body main body 110b and lid body 120 in exterior body 10b according to Modification 2 of the embodiment.

[0057] 8 and 9, exterior body 10b according to this modification has exterior body main body 110b and lid body 120, and with first wall portion 115 of exterior body main body 110b inserted into groove portion 127 of lid body 120, first wall portion 115 and groove portion 127 are joined together with adhesive 180. In this configuration, exterior body 10b according to this modification and exterior body 10 according to the embodiment are common.

[0058] This modified example differs from the above embodiment in that a plurality of storage sections 216 are provided in the first wall portion 115. Specifically, the storage sections 216 are arranged side by side in the first direction (Z-axis direction) on the opposing surface 115a of the first wall portion 115.

[0059] According to this configuration, a plurality of recessed accommodating sections 216 are arranged side by side on opposing surface 115a in the attachment direction (first direction, Z-axis direction) of one of exterior body main body 110b and lid body 120 relative to the other, thereby forming an uneven shape on opposing surface 115a. Therefore, as shown in Fig. 9, adhesive 180 hardens in a state of being in close contact with this uneven shape, thereby further improving the bonding strength between exterior body main body 110b and lid body 120 by adhesive 180.

[0060] 9, in this modification, three recessed accommodating portions 216 are arranged side by side in the Z-axis direction on opposing surface 115a of first wall portion 115, but the number of accommodating portions 216 arranged side by side in the Z-axis direction may be two or four or more. Furthermore, the multiple accommodating portions 216 arranged side by side in the Z-axis direction may be provided on other opposing surfaces (opposing surfaces 115b, 127a, 127b) instead of or in addition to opposing surface 115a.

[0061] [3-3. Variation 3] Fig. 10 is a perspective view of exterior body main body 110c according to Modification 3 of the embodiment. Fig. 10 shows an enlarged view of a portion of first wall portion 115 arranged on the periphery of main body opening 111. Fig. 11 is a perspective cross-sectional view showing a joining portion between exterior body main body 110c and lid body 120 in exterior body 10c according to Modification 3 of the embodiment.

[0062] 10 and 11, exterior body 10c according to this modification has exterior body main body 110c and lid body 120, and with first wall portion 115 of exterior body main body 110c inserted into groove portion 127 of lid body 120, first wall portion 115 and groove portion 127 are joined together with adhesive 180. This configuration is common to exterior body 10c according to this modification and exterior body 10 according to the embodiment.

[0063] This modification differs from the above embodiment in that a storage portion 217 formed in a notch shape from the tip end in the positive direction of the Z axis is provided in the first wall portion 115. That is, the energy storage device 1 according to this modification will be described as follows.

[0064] The energy storage device 1 includes an exterior body 10c that houses the energy storage element 20. The exterior body 10c includes an exterior body main body 110c and a lid body 120 joined to the exterior body main body 110c. The exterior body main body 110c has a first wall portion 115 that stands along a first direction (the Z-axis direction in this modification) that is the attachment direction of one of the lid body 120 and the exterior body main body 110c relative to the other. The lid body 120 has a groove portion 127 into which the first wall portion 115 is inserted in the Z-axis direction and which is joined to the first wall portion 115 with adhesive 180. The first wall portion 115 is provided with a notched storage portion 217 that is formed from a tip portion facing an inner bottom surface 127c of the groove portion 127 and that houses the adhesive 180.

[0065] According to this configuration, exterior body main body 110c and lid body 120 are joined together with adhesive 180 in a state in which first wall portion 115 of exterior body main body 110c is inserted into groove portion 127 of lid body 120. In this joining structure, first wall portion 115 of exterior body main body 110c is provided with accommodation portion 217 formed in a notch shape from its tip. Therefore, the adhesion area (area in close contact with adhesive 180) of first wall portion 115 is larger than in a case in which accommodation portion 217 is not provided, thereby improving the joining strength between exterior body main body 110c and lid body 120. Furthermore, even if first wall portion 115 is inserted into groove portion 127 after a relatively large amount of adhesive 180 has been poured into groove portion 127, overflow of adhesive 180 from groove portion 127 is suppressed by accommodation portion 217 containing adhesive 180. Therefore, for example, a relatively large amount of adhesive 180 can improve the bonding strength between exterior body main body 110c and lid body 120, and strict control of the amount of adhesive 180 and the need to wipe off overflowing adhesive 180 are not required. Furthermore, since accommodating portion 217 is provided in a notched shape from the tip end in the insertion direction (positive direction of the Z axis) into groove portion 127 of first wall portion 115, adhesive 180 is easily accommodated in accommodating portion 217. In other words, when first wall portion 115 is inserted into groove portion 127, accommodating portion 217 can efficiently accommodate adhesive 180. This also contributes to preventing overflow of adhesive 180 from groove portion 127. In this way, power storage device 1 according to this modification is a power storage device with a simple configuration and improved reliability.

[0066] Furthermore, since the storage section 217 is provided in the form of a notch from the tip of the first wall section 115, the first wall section 115 having the storage section 217 can be molded together with the entire exterior body main body 110c, for example, using the mold used to mold the exterior body main body 110c.

[0067] 10 and 11, the shape of the accommodation portion 217 when viewed from the second direction (the Y-axis direction in FIG. 11) is a simple rectangle that is elongated in the Z-axis direction. However, the shape of the accommodation portion 217 when viewed from the second direction may be various shapes, such as a U-shape or a V-shape. Furthermore, the accommodation portion 217 may be provided without penetrating the first wall portion 115 in the thickness direction (second direction). For example, the accommodation portion 217 may be provided as a groove that is recessed from the opposing surface 115a and opens to the tip of the first wall portion 115 in the positive Z-axis direction.

[0068] [3-4. Variation 4] Fig. 12 is a perspective cross-sectional view showing the joint portion between exterior body main body 110d and lid body 120 in exterior body 10d according to Variation 4 of the embodiment. As shown in Fig. 12, exterior body 10d according to this variation has exterior body main body 110d and lid body 120, and with first wall portion 115 of exterior body main body 110d inserted into groove portion 127 of lid body 120, first wall portion 115 and groove portion 127 are joined together with adhesive 180. In this configuration, exterior body 10d according to this variation and exterior body 10 according to the embodiment are common.

[0069] This modification differs from the above embodiment in that an inclined surface 118 is formed at the tip end portion in the positive Z-axis direction of the first wall portion 115. Specifically, the energy storage device 1 according to this modification will be described as follows.

[0070] The energy storage device 1 includes an exterior body 10d that houses the energy storage element 20. The exterior body 10d includes an exterior body main body 110d and a lid body 120 joined to the exterior body main body 110d. The exterior body main body 110d has a first wall portion 115 that stands along a first direction (the Z-axis direction in this modification) that is the attachment direction of one of the lid body 120 and the exterior body main body 110d relative to the other. The lid body 120 has a groove portion 127 into which the first wall portion 115 is inserted in the Z-axis direction and joined to the first wall portion 115 with adhesive 180. The first wall portion 115 has an inclined surface 118 provided at the tip portion in the insertion direction of the first wall portion 115 into the groove portion 127 (the positive direction of the Z-axis). The inclined surface 118 is inclined so as to move away from the inner bottom surface 127c of the groove portion 127 as it goes from one end of the first wall portion 115 to the other end in the second direction (the Y-axis direction in Figure 12), which is the thickness direction of the first wall portion 115.

[0071] According to this configuration, when the first wall portion 115 is inserted into the groove portion 127, the main movement direction of the adhesive 180, which is pushed out by the first wall portion 115 and moves within the groove portion 127, can be controlled by the inclined surface 118. In this modification, it is necessary to prevent the adhesive 180 from overflowing toward the exterior of the exterior body 10d, i.e., toward the negative Y-axis direction, which is one of the thickness directions (second direction) of the first wall portion 115. In this case, as shown in FIG. 12 , the tip of the first wall portion 115 is formed with an inclined surface 118 that is inclined away from the inner bottom surface 127c of the groove portion 127 as it moves from the negative Y-axis direction to the positive Y-axis direction. In this case, the inclined surface 118 pushes the adhesive 180 mainly toward the positive Y-axis direction, i.e., toward the interior of the exterior body 10d. As a result, overflow of the adhesive 180 from the joint portion between the exterior body main body 110d and the lid 120 toward the exterior of the exterior body 10d is more reliably prevented.

[0072] Note that inclined surface 118 does not need to be a flat surface and may be a curved surface. Furthermore, exterior body 10d according to this modification may further include a storage portion (storage portions 116, 129, 216, etc.) formed in a recessed shape in at least one of facing surfaces 115a and 115b of first wall portion 115 and facing surfaces 127a and 127b of groove portion 127. For example, by providing a storage portion in at least one of facing surfaces 127a and 115a, which is closer to the outside of exterior body 10d, adhesive 180 that flows toward the outside of groove portion 127 of exterior body 10d can be stored in the storage portion. This makes it possible to more reliably prevent adhesive 180 from spilling out of exterior body 10d. Furthermore, for example, by providing a storage portion on at least one of opposing surfaces 115b and 127b that is close to the interior of exterior body 10d, adhesive 180 that is guided by inclined surface 118 within groove portion 127 to the interior side of exterior body 10d can be stored in the storage portion. In other words, inclined surface 118 can prevent adhesive 180 from spilling out of exterior body 10d, while the storage portion can also prevent adhesive 180 from spilling into the interior of exterior body 10d.

[0073] (Other embodiments) Although the energy storage device 1 according to the embodiment of the present invention and its modified examples have been described above, the present invention is not limited to these embodiments and modified examples. In other words, the embodiments disclosed herein are illustrative in all respects and are not restrictive, and the scope of the present invention includes all modifications within the meaning and scope of the claims.

[0074] For example, in the exterior body 110 according to the embodiment, as shown in Fig. 3, the storage sections 116 are provided continuously over the entire area in the extension direction (X-axis direction and Y-axis direction) of the first wall section 115, but the storage sections 116 may be formed intermittently in the extension direction. That is, the storage sections 116 may be arranged in a dispersed manner in a third direction (for example, the X-axis direction in Fig. 6) perpendicular to the first direction and the second direction. In this case, the number, positions, etc. of the storage sections 116 may be determined depending on, for example, the volume of adhesive 180 that can be stored in each storage section 116, etc.

[0075] Furthermore, the cross-sectional shape and size of the accommodation portion 116 do not have to be the cross-sectional shape and size shown in Figures 5 and 6. For example, a groove with a V-shaped cross section may be provided as accommodation portion 116 on an opposing surface such as opposing surface 115a.

[0076] Furthermore, the first member and second member joined by the joining structure shown in Fig. 6 etc. are not limited to the combination of exterior body main body 110 and lid body 120. For example, if exterior body main body 110 includes a member (e.g., referred to as an "inner lid") that separates the space in which energy storage element unit 24 (see Fig. 2) is housed from another space, the joining structure shown in Fig. 6 etc. may be used to join exterior body main body 110, which is the first member, to the inner lid, which is the second member.

[0077] Furthermore, the shape of exterior body 10 does not need to be a substantially rectangular parallelepiped (box-like). For example, a joining structure shown in Fig. 6 or the like may be used to join a cylindrical exterior body main body with one end closed to an exterior body configured with a lid body that is circular in plan view and covers a circular opening.

[0078] Furthermore, embodiments constructed by arbitrarily combining the plurality of components described above are also included within the scope of the present invention. For example, a plurality of storage sections 216 arranged in the Z-axis direction as shown in Fig. 9 may be disposed in the first wall section 115 instead of the storage section 116 shown in Fig. 7. Furthermore, the storage section 217 formed as a notch from the tip of the first wall section 115 as shown in Fig. 11 may be provided in the first wall section 115 having the inclined surface 118 as shown in Fig. 12. In other words, two or more of the configurations of the storage sections and the like described in each of the embodiment and Modifications 1 to 4 may be selected and combined. [Industrial Applicability]

[0079] 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]

[0080] 1. Energy storage device 10, 10a, 10b, 10c, 10d Exterior body 20 Energy storage element 110, 110b, 110c, 110d exterior body 111 Main body opening 115 First wall 115a, 115b, 127a, 127b Opposite surface 116, 129, 216, 217 Storage section 116a Inside surface 118 Slope 120, 120a lid body 125, 128 Second wall section 127 Groove 127c Inner bottom surface 180 Adhesive

Claims

1. An electricity storage device including an exterior body that houses an electricity storage element, the exterior body includes a first member and a second member joined to the first member, the first member has a wall portion erected along a first direction which is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove into which the wall portion is inserted in the first direction and which is joined to the wall portion with an adhesive; an opposing surface of one of the wall portion and the groove portion that faces the other in a second direction that is a thickness direction of the wall portion, the opposing surface having a recess formed in the second direction from the opposing surface, the recess being configured to accommodate the adhesive; the housing portion is disposed on the opposing surface at a position farther from an inner bottom surface of the groove than a tip end of the wall portion in an insertion direction into the groove; Energy storage device.

2. An electricity storage device including an exterior body that houses an electricity storage element, the exterior body includes a first member and a second member joined to the first member, the first member has a wall portion erected along a first direction which is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove into which the wall portion is inserted in the first direction and which is joined to the wall portion with an adhesive; an opposing surface of one of the wall portion and the groove portion that faces the other in a second direction that is a thickness direction of the wall portion, the opposing surface having a recess formed in the second direction from the opposing surface, the recess being configured to accommodate the adhesive; the storage portion is one of a plurality of inner surfaces that form a storage space for the adhesive, and has an inner surface that faces a direction in which one of the wall portion and the groove portion in which the storage portion is provided is removed from the other, The adhesive is accommodated in the accommodation portion in a state of being in close contact with the inner surface. Energy storage device.

3. the first member and the second member are members that separate the inside and the outside of the exterior body, The storage portion is provided on the opposing surface of the wall portion facing the outside of the exterior body, or on the opposing surface of the groove portion located closer to the outside of the exterior body than the wall portion. The electricity storage device according to claim 1 or 2.

4. An electricity storage device including an exterior body that houses an electricity storage element, the exterior body includes a first member and a second member joined to the first member, the first member has a wall portion erected along a first direction which is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove into which the wall portion is inserted in the first direction and which is joined to the wall portion with an adhesive; an opposing surface of one of the wall portion and the groove portion that faces the other in a second direction that is a thickness direction of the wall portion, the opposing surface having a recess formed in the second direction from the opposing surface, the recess being configured to accommodate the adhesive; The accommodating portions are arranged in a plurality in the first direction on the opposing surfaces of the one of the wall portion and the groove portion. Energy storage device.

5. the wall portion has an inclined surface provided at a tip end portion of the wall portion in a direction of insertion into the groove portion, The inclined surface is inclined so as to move away from the inner bottom surface of the groove portion as it goes from one end to the other end of the wall portion in the second direction. The electricity storage device according to any one of claims 1 to 4.

6. An electricity storage device including an exterior body that houses an electricity storage element, the exterior body includes a first member and a second member joined to the first member, the first member has a wall portion erected along a first direction which is an attachment direction of one of the second member and the first member relative to the other, the second member has a groove into which the wall portion is inserted in the first direction and which is joined to the wall portion with an adhesive; The wall portion is provided with a storage portion for storing the adhesive, the storage portion being formed in a notched shape from a tip end portion facing the inner bottom surface of the groove portion. Energy storage device.

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