Power storage device

Abstract

To provide a power storage device capable of suppressing reduction of junction quality.SOLUTION: Provided is a power storage device comprising a power storage element, and the power storage device includes a first member 130 and a second member 140 which are joined in a first direction Z. The second member includes a first wall part 143 and a second wall part 144 which are two wall parts extending in a second direction X and a third direction Y which are two directions orthogonal with the first direction. The second wall part is joined with the first member, and the first member includes an opposed portion 131 opposed to a position, where the first wall part and the second wall part are overlapped, and a first adjacent portion 132 which is adjacent with the opposed portion in the second direction and opposed to the first wall part.SELECTED DRAWING: Figure 9

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses a battery module including a battery cell laminate in which a plurality of battery cells are laminated, a lower frame covering the lower surface and both side surfaces of the battery cell laminate, and an upper frame covering the upper surface of the battery cell laminate, wherein the lower frame and the upper frame are joined by laser welding.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] As disclosed in the above Patent Document 1, in a configuration in which two members (the lower frame and the upper frame in Patent Document 1) are joined, a gap may occur between the two members when the two members are joined. When such a gap occurs, there is a risk that the joining quality of the two members deteriorates, such as poor airtightness or a decrease in joining strength between the two members.

[0005] The present invention has been made by the inventors of the present application newly paying attention to the above problems, and an object thereof is to provide a power storage device capable of suppressing a decrease in joining quality.

Means for Solving the Problems

[0006] A power storage device according to an aspect of the present invention is a power storage device including a power storage element, and includes a first member and a second member joined in a first direction. The second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, i.e., a second direction and a third direction. The second wall portion is joined to the first member. The first member includes a facing portion facing a position where the first wall portion and the second wall portion overlap, and a first adjacent portion adjacent to the facing portion in the second direction and facing the first wall portion. The facing portion is thicker than the first adjacent portion in the first direction and protrudes in a direction opposite to the second member with respect to the first adjacent portion.

[0007] A power storage device according to another aspect of the present invention is a power storage device including a power storage element, and includes a first member and a second member joined in a first direction. The second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, i.e., a second direction and a third direction. The second wall portion is joined to the first member. The first member includes a facing portion facing a position where the first wall portion and the second wall portion overlap, a first adjacent portion adjacent to the facing portion in the second direction and facing the first wall portion, and a second adjacent portion adjacent to the facing portion in the third direction and facing the second wall portion. At least one of the first member and the second member is formed with at least one of a first recess in which a surface of the first adjacent portion facing the first wall portion is recessed more than a surface of the second adjacent portion facing the second wall portion, and a second recess in which a surface of the first wall portion facing the first adjacent portion is recessed more than a surface of the second wall portion facing the second adjacent portion.

Advantages of the Invention

[0008] According to the power storage device of the present invention, a decrease in joining quality can be suppressed.

Brief Description of the Drawings

[0009]

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[0010] (1) A power storage device according to one aspect of the present invention is a power storage device including a power storage element, and includes a first member and a second member joined in a first direction. The second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, i.e., a second direction and a third direction. The second wall portion is joined to the first member. The first member includes an opposing portion facing a position where the first wall portion and the second wall portion overlap, and a first adjacent portion adjacent to the opposing portion in the second direction and facing the first wall portion. The opposing portion is thicker than the first adjacent portion in the first direction and protrudes in a direction opposite to the second member from the first adjacent portion.

[0011] According to the power storage device according to one aspect of the present invention, the second wall portion is joined to the first member, and the first member includes an opposing portion facing the position where the first wall portion and the second wall portion overlap, and a first adjacent portion adjacent to the opposing portion and facing the first wall portion. In this configuration, when the second wall portion and the first member are joined, the position where the first wall portion and the second wall portion overlap may be recessed more than other portions of the first wall portion, causing the opposing portion to lift off from the second member. In this case, a gap is generated between the opposing portion and the second member, and there is a risk that the joint quality between the first member and the second member deteriorates, such as airtightness failure or a decrease in joint strength between the first member and the second member. Therefore, according to the power storage device according to one aspect of the present invention, the opposing portion is thicker than the first adjacent portion and protrudes in a direction opposite to the second member from the first adjacent portion. Thereby, since the first member can be pressed against the second member at the position of the opposing portion, it is possible to suppress the opposing portion from lifting off from the second member. Therefore, it is possible to suppress the generation of a gap between the opposing portion and the second member, and thus suppress the deterioration of the joint quality between the first member and the second member due to the generation of the gap.

[0012] (2) In the power storage device according to the above (1), the first member may further include a second adjacent portion adjacent to the opposing portion in the third direction, and the opposing portion may be thicker than the second adjacent portion in the first direction and protrude in a direction opposite to the second member from the second adjacent portion.

[0013] According to the power storage device according to the above (2), in the first member, the opposing portion is thicker than the second adjacent portion and protrudes in a direction opposite to the second member from the second adjacent portion. Thereby, since the first member can be more reliably pressed against the second member at the position of the opposing portion, it is possible to more effectively suppress the opposing portion from lifting off from the second member.

[0014] (3) The power storage device according to another aspect of the present invention is a power storage device including a power storage element, and includes a first member and a second member joined in a first direction. The second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, i.e., a second direction and a third direction. The second wall portion is joined to the first member. The first member includes an opposing portion facing a position where the first wall portion and the second wall portion overlap, a first adjacent portion adjacent to the opposing portion in the second direction and facing the first wall portion, and a second adjacent portion adjacent to the opposing portion in the third direction and facing the second wall portion. At least one of the first member and the second member is formed with at least one of a first recess in which a surface of the first adjacent portion facing the first wall portion is recessed more than a surface of the second adjacent portion facing the second wall portion, and a second recess in which a surface of the first wall portion facing the first adjacent portion is recessed more than a surface of the second wall portion facing the second adjacent portion.

[0015] According to the power storage device according to another aspect of the present invention, the second wall portion is joined to the first member. The first member includes an opposing portion facing a position where the first wall portion and the second wall portion overlap, a first adjacent portion adjacent to the opposing portion and facing the first wall portion, and a second adjacent portion adjacent to the opposing portion and facing the second wall portion. In this configuration, when the second wall portion and the first member are joined, the position where the first wall portion and the second wall portion overlap may be recessed more than other portions of the first wall portion, so that the opposing portion may lift off from the second member. In this case, a gap is generated between the opposing portion and the second member, and there is a risk that the joining quality of the first member and the second member deteriorates, such as airtightness failure or a decrease in joining strength between the first member and the second member. Therefore, according to the power storage device according to another aspect of the present invention, at least one of the first member and the second member is formed with at least one of a first recess in which a surface of the first adjacent portion is recessed more than a surface of the second adjacent portion, and a second recess in which a surface of the first wall portion is recessed more than a surface of the second wall portion. Thereby, since the other can be disposed in at least one of the recesses of the first adjacent portion and the first wall portion, it is possible to suppress the opposing portion from lifting off from the second member. Therefore, it is possible to suppress the generation of a gap between the opposing portion and the second member, and thus it is possible to suppress the deterioration of the joining quality of the first member and the second member due to the generation of the gap.

[0016] (4) In the power storage device according to (3) above, at least one of the first recess and the second recess may be a part of the recess extending in the second direction formed in at least one of the first member and the second member.

[0017] According to the power storage device described in (4) above, at least one of the first recess and the second recess is a part of the recess extending in the second direction formed in at least one of the first member and the second member. As a result, by arranging the other one in the recess extending in the second direction of at least one of the first adjacent portion and the first wall portion, it becomes easier to bring the facing portion closer to the position where the first wall portion and the second wall portion overlap, so that it is possible to more effectively suppress the facing portion from lifting off the second member.

[0018] (5) In the power storage device according to any one of (1) to (4) above, the light transmittance of the first member may be higher than the light transmittance of the second member, and the light absorption rate of the second member may be higher than the light absorption rate of the first member.

[0019] According to the power storage device described in (5) above, since the light transmittance of the first member is higher than the light transmittance of the second member, and the light absorption rate of the second member is higher than the light absorption rate of the first member, light such as laser light can be transmitted through the first member to join the first member and the second member. At this time, when joining the first member and the second wall portion of the second member, the position where the first wall portion and the second wall portion overlap may melt and become recessed compared to other portions of the first wall portion. Even in this case, since the first member can be pressed against the second member at the position of the facing portion, it is possible to suppress the facing portion from lifting off the second member.

[0020] (6) In the power storage device according to any one of (1) to (5) above, the first member and the second member may be two members provided in the case for housing the power storage element.

[0021] According to the power storage device described in (6) above, since the first member and the second member are two members provided in the case that houses the power storage element, it is possible to suppress a decrease in joining quality when manufacturing the case.

[0022] Hereinafter, a power storage device according to an embodiment (including a modified example thereof) of the present invention will be described with reference to the drawings. Each of the embodiments described below shows comprehensive or specific examples. The numerical values, shapes, materials, components, arrangement positions and connection forms of the components, manufacturing processes, order of manufacturing processes, etc. shown in the following embodiments are examples and are not intended to limit the present invention. In each figure, the dimensions and the like are not strictly illustrated. In each figure, the same or similar components are denoted by the same reference numerals.

[0023] In the following description and drawings, the arrangement direction of a plurality of power storage elements, the opposing direction of a pair of long side surfaces in the container of one power storage element, or the thickness direction of the power storage element is defined as the X-axis direction. The arrangement direction of a pair of terminals (positive electrode and negative electrode) of one power storage element, or the opposing direction of a pair of short side surfaces in the container of one power storage element is defined as the Y-axis direction. The arrangement direction of the main body and the lid of the case of the power storage device, the arrangement direction of the main body and the lid of the container of one power storage element, or the vertical direction is defined as the Z-axis direction. These X-axis direction, Y-axis direction and Z-axis direction are directions that intersect (orthogonal in this embodiment) with each other. Although it is conceivable that the Z-axis direction may not be the vertical direction depending on the usage mode, hereinafter, for the sake of convenience of explanation, the Z-axis direction will be described as the vertical direction.

[0024] In the following description, the positive X-axis direction indicates the direction of the arrow on the X-axis, and the negative X-axis direction indicates the direction opposite to the positive X-axis direction. When simply referring to the X-axis direction, it indicates both directions of the positive X-axis direction and the negative X-axis direction or either one of them. When referring to one side and the other side of the X-axis direction, it indicates one and the other of the positive X-axis direction and the negative X-axis direction. The same applies to the Y-axis direction and the Z-axis direction. Hereinafter, the Z-axis direction is also referred to as the first direction, the X-axis direction is also referred to as the second direction, and the Y-axis direction is also referred to as the third direction. Expressions indicating relative directions or postures such as parallel and perpendicular include cases where they are not strictly in that direction or posture. When two directions are parallel (or perpendicular), it means not only that the two directions are completely parallel (or perpendicular), but also that they are substantially parallel (or perpendicular), that is, including a difference of about several percent. In the following description, when expressing "insulation", it means "electrical insulation". A material having insulating properties preferably has a volume resistivity of 1×10 6 Ωm or more, more preferably 1×10 7 Ωm or more, and even more preferably 1×10 10 Ωm or more and is formed of such a material.

[0025] (Embodiment) [1 General description of the power storage device 1] First, a general description of the power storage device 1 in this embodiment will be given. FIG. 1 is a perspective view showing the appearance of the power storage device 1 according to this embodiment. FIG. 2 is an exploded perspective view showing each component when the power storage device 1 according to this embodiment is disassembled.

[0026] The power storage device 1 is a device that can charge electricity from the outside and discharge electricity to the outside. In this embodiment, it has a cuboid shape. A cuboid is a hexahedron in which all faces are composed of rectangles or squares. The power storage device 1 is used for power storage applications, power supply applications, etc. Specifically, the power storage device 1 is used as a battery for driving a moving body such as an automobile, a motorcycle, a watercraft, a ship, a snowmobile, an agricultural machine, a construction machine, an automatic guided vehicle (AGV), or a railway vehicle for electric railways, or for engine starting, etc. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, light oil, liquefied natural gas, etc.) automobiles. Examples of the above-mentioned railway vehicles for electric railways include trains, monorails, linear motor cars, and hybrid trains 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, etc.

[0027] As shown in FIGS. 1 and 2, the power storage device 1 includes a case 10, a plurality of power storage elements 20, a plurality of bus bars 30 and 60, a holding member 40, and a substrate 50. In addition to the above configuration, the power storage device 1 may also include a spacer disposed between the plurality of power storage elements 20, a restraining member (such as a side plate, an end plate, etc.) for restraining the plurality of power storage elements 20.

[0028] [1.1 Explanation of the case 10] The case 10 is a container (module case) having a substantially rectangular parallelepiped shape (box shape) that constitutes the exterior body (housing, outer shell) of the power storage device 1. The case 10 is disposed outside a plurality of power storage elements 20, bus bars 30, 60, holding members 40, a substrate 50, etc., and arranges and houses these power storage elements 20, etc. at predetermined positions to protect them from impacts and the like. The case 10 is formed of 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), polyether sulfone (PES), polyamide (PA), ABS resin, or a composite material thereof. Thereby, the case 10 avoids the power storage elements 20, etc. from coming into contact with external metal members, etc.

[0029] The case 10 includes a case lid 100 that constitutes the lid of the case 10 and a case body 200 that constitutes the main body of the case 10. The case lid 100 is a flat rectangular member that closes the opening of the case body 200. The case body 200 is a bottomed rectangular cylindrical housing (housing) having an opening formed in the +Z-axis direction and houses the power storage elements 20, etc. The case lid 100 and the case body 200 are joined by adhesion with an adhesive or the like, welding such as laser welding, thermal welding, or ultrasonic welding, or mechanical joining such as bolt joining or caulking. Thereby, the case 10 has a structure in which the inside is sealed. The case lid 100 and the case body 200 may be formed of members of the same material or members of different materials.

[0030] The case lid 100 is provided with a pair of external terminals (main terminals) 110 and 120 for connecting to the outside of the power storage device 1 (a positive electrode and a negative electrode). The external terminals 110 and 120 are formed of conductive members made of metal such as aluminum or aluminum alloy. The external terminal 110 is the external terminal of the positive electrode, and the external terminal 120 is the external terminal of the negative electrode. The external terminals 110 and 120 are electrically connected to the power storage element 20, and the power storage device 1 charges electricity from the outside and discharges electricity to the outside via the external terminals 110 and 120.

[0031] The case lid 100 includes a first member 130, a second member 140, a third member 150, an exhaust part 160, and a wiring holding part 161. The second member 140 is a part that constitutes the main body of the case lid 100, and the above-mentioned external terminals 110 and 120 are arranged thereon. Openings (openings 141 and 146 described later) are formed at both ends in the X-axis direction of the central part in the Y-axis direction of the second member 140. The first member 130 and the third member 150 are flat lid members (small lids) that close the above-mentioned openings formed in the second member 140. Specifically, the first member 130 is arranged at the end in the positive X-axis direction of the central part in the Y-axis direction of the second member 140 and closes the opening (opening 141) facing the connecting member or the like from the external terminal 110 to the power storage element 20. The third member 150 is arranged at the end in the negative X-axis direction of the central part in the Y-axis direction of the second member 140 and closes the opening (opening 146) facing the connecting member or the like from the external terminal 120 to the power storage element 20.

[0032] The exhaust portion 160 is an exhaust pipe that extends in the positive X-axis direction from the second member 140 at the end in the positive X-axis direction at the center in the Y-axis direction of the second member 140. The exhaust portion 160 is connected to the exhaust path of the gas discharged from the gas discharge valve 24 of the power storage element 20, and exhausts the gas to the outside of the power storage device 1. The exhaust portion 160 is formed integrally with the second member 140, but may be configured separately from the second member 140. The wiring holding portion 161 is a connector disposed at the end in the negative X-axis direction (inside the opening 146) at the center in the Y-axis direction of the second member 140. The wiring holding portion 161 holds the wiring electrically connected to the power storage element 20 and is connected to an external conductive member (such as external wiring). The wiring holding portion 161 is configured separately from the second member 140, but may be formed integrally with the second member 140.

[0033] The first member 130, the second member 140, the third member 150, the exhaust portion 160, and the wiring holding portion 161 may all be formed of members of the same material, or any of them may be formed of members of different materials. A more detailed description of the configuration of the case lid 100 will be described later.

[0034] [1.2 Description of the power storage element 20] The power storage element 20 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The power storage element 20 has a flat rectangular parallelepiped shape (rectangular or box-shaped) in the X-axis direction. In the present embodiment, 12 power storage elements 20 are arranged side by side in the X-axis direction. The size, shape, and the number of power storage elements 20 to be arranged are not limited, and the power storage element 20 may be a cylindrical shape (cylindrical), an elliptical cylindrical shape, an elliptical columnar shape, a polygonal columnar shape other than a rectangular parallelepiped, or only one power storage element 20 may be arranged. The power 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 (such as a lead storage battery), or may be a capacitor. The power storage element 20 may be a primary battery instead of a secondary battery. The power storage element 20 may be a battery using a solid electrolyte. The power storage element 20 may be a pouch-type power storage element.

[0035] The energy storage element 20 includes a container 21 and a pair of terminals (a positive electrode and a negative electrode) 22. Inside the container 21, an electrode body, a pair of current collectors (a positive electrode and a negative electrode), an electrolytic solution (non-aqueous electrolyte), etc. are accommodated, and a gasket is disposed between the container 21, the terminals 22, and the current collectors, but the illustration thereof is omitted. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the energy storage element 20, and various types can be selected.

[0036] The container 21 is a rectangular parallelepiped-shaped (square or box-shaped) container including a container body 21a having an opening formed therein and a container lid portion 21b closing the opening of the container body 21a. The container body 21a has a pair of long side surfaces on both side surfaces in the X-axis direction, a pair of short side surfaces on both side surfaces in the Y-axis direction, a bottom surface in the negative Z-axis direction, and the container lid portion 21b is disposed in the positive Z-axis direction. The container lid portion 21b is provided with a gas discharge valve 24 for releasing the pressure when the pressure inside the container 21 rises excessively, a liquid injection portion (not shown) for injecting the electrolytic solution into the container 21, and the like. The material of the container 21 is not particularly limited, and it can be a weldable metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but a resin can also be used.

[0037] The terminals 22 are electrode terminals (a positive electrode terminal and a negative electrode terminal) of the energy storage element 20 disposed on the container lid portion 21b. The terminals 22 are disposed to protrude in the positive Z-axis direction from the container lid portion 21b. The terminals 22 are metal members for leading the electricity stored in the electrode body to the external space of the energy storage element 20 and introducing electricity into the internal space of the energy storage element 20 to store electricity in the electrode body. The terminals 22 are formed of aluminum, aluminum alloy, copper, copper alloy, or the like.

[0038] The electrode body is a power storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. The positive electrode plate is formed by forming a positive electrode active material layer on a current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is formed by forming a negative electrode active material layer on a current collector foil made of a metal such as copper or a copper alloy. As the active material used in the positive electrode active material layer and the negative electrode active material layer, any known material can be appropriately used as long as it can occlude and release charge transport ions. As the separator, a microporous sheet or non-woven fabric made of resin can be used. In the present embodiment, the electrode body is formed by laminating electrode plates (positive electrode plate and negative electrode plate) in the X-axis direction. The electrode body may be any form of electrode body, such as a wound type electrode body formed by winding electrode plates (positive electrode plate and negative electrode plate), a laminated type (stack type) electrode body formed by laminating a plurality of flat electrode plates, or a bellows type electrode body formed by folding the electrode plates in a bellows shape.

[0039] The current collector is a conductive current collecting member (positive current collector and negative current collector) that is electrically connected to the terminal 22 and the electrode body. The positive current collector is formed of aluminum or an aluminum alloy, etc., similar to the current collector foil of the positive electrode plate of the electrode body, and the negative current collector is formed of copper or a copper alloy, etc., similar to the current collector foil of the negative electrode plate of the electrode body. The gasket is disposed between the container lid portion 21b, the terminal 22, and the current collector, and insulates and seals between the container lid portion 21b, the terminal 22, and the current collector. The gasket may be formed of any material as long as it has insulating properties.

[0040] [1.3 Explanation of Other Components] The bus bar 30 is a rectangular plate-like member disposed on a plurality of power storage elements 20 and electrically connecting the terminals 22 of the plurality of power storage elements 20 to each other. The bus bar 60 is a rectangular plate-like member disposed on the holding member 40 and electrically connecting the bus bar 30 to the external terminals 110 and 120. The bus bars 30 and 60 are formed of a metal conductive member such as aluminum, an aluminum alloy, copper, a copper alloy, nickel, etc., or a combination thereof, or a conductive member other than metal.

[0041] In this embodiment, among the bus bars 30, the bus bar 31 is connected to the positive terminals 22 of the three power storage elements 20 arranged at the X-axis positive direction end, and the bus bar 32 is connected to the negative terminals 22 of the three power storage elements 20 arranged at the X-axis negative direction end. The bus bar 33 connects the power storage elements 20 in sets of three in parallel to form four sets of power storage element groups, and connects the four sets of power storage element groups in series. Among the bus bars 60, one end of the bus bar 61 is connected to the bus bar 31, and the other end is connected to the external terminal 110. One end of the bus bar 62 is connected to the bus bar 32, and the other end is connected to the external terminal 120. That is, the bus bars 61 and 31 are part of the connection members from the external terminal 110 to the power storage element 20, and the bus bars 62 and 32 are part of the connection members from the external terminal 120 to the power storage element 20. The bus bar 61 is provided with a fuse or a relay or the like in the middle of the conductive path.

[0042] The holding member 40 is a member (such as a bus bar frame) that holds the substrate 50, the bus bar 60, and wirings (not shown). The substrate 50 is placed on the holding member 40 and is a control substrate fixed to the holding member 40. The substrate 50 is connected to a plurality of power storage elements 20 by wirings or the like, and acquires, monitors, and controls the states of the plurality of power storage elements 20.

[0043] [Description of the two-case lid 100] Next, the configuration of the case lid 100 will be described in more detail. FIG. 3 is a perspective view showing the configuration of the case lid 100 of the power storage device 1 according to this embodiment with the first member 130 and the third member 150 removed. FIG. 4 is a plan view showing the configuration of the case lid 100 of the power storage device 1 according to this embodiment with the first member 130 and the third member 150 removed.

[0044] As shown in FIGS. 3 and 4, in the case lid 100, openings 141 and 146 are formed in the second member 140. The openings 141 and 146 are through holes that penetrate the second member 140 in its thickness direction (Z-axis direction). The opening 141 is a through hole disposed at the end in the positive X-axis direction at the center in the Y-axis direction of the second member 140, and the opening 146 is a through hole disposed at the end in the negative X-axis direction at the center in the Y-axis direction of the second member 140.

[0045] The openings 141 and 146 are openings for externally connecting the bus bars 111 and 121 (see FIG. 4) connected to the external terminals 110 and 120 and the bus bars 61 and 62. Specifically, bus bars 111 and 121 connected to the external terminals 110 and 120 are disposed in the second member 140 by insert molding or the like, and the ends of the bus bars 111 and 121 are exposed from the openings 141 and 146. By externally connecting the ends of the bus bars 111 and 121 and the ends of the bus bars 61 and 62 through the openings 141 and 146, the external terminals 110 and 120 and the bus bars 61 and 62 can be easily connected. The opening 141 is also an opening that forms an exhaust path for gas from the power storage element 20 to the exhaust portion 160. The opening 146 is also an opening where the wiring holding portion 161 is disposed.

[0046] The second member 140 includes a wall portion 142 that rises in the Z-axis direction around the opening 141. The wall portion 142 is a plate-like wall member disposed so as to surround the opening 141. The wall portion 142 includes a first wall portion 143 and a second wall portion 144. The first wall portion 143 is a plate-like wall member extending in the X-axis direction, and in the present embodiment, it is disposed to protrude in the negative X-axis direction toward the inside of the opening 141. The second wall portion 144 is a plate-like wall member extending in the Y-axis direction, and in the present embodiment, it is disposed to protrude in the positive Y-axis direction toward the inside of the opening 141. The first wall portion 143 and the second wall portion 144 are arranged to intersect (orthogonal in the present embodiment) with each other. The second member 140 includes a wall portion 147 that rises in the Z-axis direction around the opening 146. The wall portion 147 is a plate-like wall member disposed so as to surround the opening 146.

[0047] In such a configuration, the first member 130 is arranged to close the opening 141, and the third member 150 is arranged to close the opening 146. Specifically, the first member 130 is joined to the wall portion 142 (such as the first wall portion 143 and the second wall portion 144) to be joined to the second member 140 and close the opening 141. The third member 150 is joined to the wall portion 147 to be joined to the second member 140 and close the opening 146.

[0048] Thus, the first member 130 and the second member 140 are two members provided in the case 10 that houses the power storage element 20, and are joined in the Z-axis direction (the first direction). Similarly, the third member 150 and the second member 140 are two members provided in the case 10 that houses the power storage element 20, and are joined in the Z-axis direction (the first direction).

[0049] The first member 130 and the third member 150 and the second member 140 can be joined by welding such as laser welding, thermal welding or ultrasonic welding, adhesion by an adhesive, or mechanical joining such as bolt joining or caulking. In the present embodiment, the first member 130 and the second member 140 (the first wall portion 143 and the second wall portion 144) are joined by laser welding. Hereinafter, the configuration in which the first member 130 and the second member 140 (the first wall portion 143 and the second wall portion 144) are joined will be described in detail.

[0050] [Explanation of the joining configuration between the first member 130 and the second member 140] FIG. 5 is a perspective view showing the first member 130 and the second member 140 according to the present embodiment. Specifically, FIG. 5 is a perspective view showing the configuration at the position where the first wall portion 143 and the second wall portion 144 in the first member 130 and the second member 140 intersect. In FIG. 5, for convenience of explanation, the structures of the first member 130 and the second member 140 (the first wall portion 143 and the second wall portion 144) are schematically shown in a simplified manner. Hereinafter, the description will be made based on the configuration shown in FIG. 5.

[0051] FIG. 6A is a perspective view showing a configuration in a state where the first member 130 according to the present embodiment is overlapped with the second member 140. FIG. 6B is a cross-sectional view showing a configuration in a state where the first member 130 according to the present embodiment is overlapped with the second member 140. FIG. 6B shows a cross-section when the configuration of FIG. 6A is cut by a plane parallel to the XZ plane passing through line VIB-VIB. FIG. 7A is a perspective view showing a configuration in a state where the first member 130 and the second wall portion 144 of the second member 140 according to the present embodiment are joined. FIG. 7B is a cross-sectional view showing a configuration in a state where the first member 130 and the second wall portion 144 of the second member 140 according to the present embodiment are joined. FIG. 7B shows a cross-section when the configuration of FIG. 7A is cut by a plane parallel to the XZ plane passing through line VIIB-VIIB. FIG. 8A is a cross-sectional view showing a configuration in a state before the first wall portion 143 of the first member 130 and the second member 140 according to the present embodiment are joined. FIG. 8B is a cross-sectional view showing a configuration in a state where the first wall portion 143 of the first member 130 and the second member 140 according to the present embodiment are joined. FIGS. 8A and 8B are views corresponding to FIG. 7B. FIG. 9 is a perspective view showing a configuration in a state where the first member 130 and the second member 140 (the first wall portion 143 and the second wall portion 144) according to the present embodiment are joined.

[0052] As shown in FIG. 5, the second member 140 includes a first wall portion 143 and a second wall portion 144, which are two wall portions extending in the X-axis direction (second direction) and the Y-axis direction (third direction), which are two directions orthogonal to the Z-axis direction (first direction). Specifically, the first wall portion 143 is a flat plate-like portion (wall) parallel to the XZ plane and extending in the X-axis direction. The second wall portion 144 is a flat plate-like portion (wall) parallel to the YZ plane and extending in the Y-axis direction. The first wall portion 143 and the second wall portion 144 are arranged to intersect in an X shape. Hereinafter, the portion (overlapping position) where the first wall portion 143 and the second wall portion 144 intersect is referred to as an intersection portion 145. The portion of the first wall portion 143 in the positive X-axis direction with respect to the intersection portion 145 is also referred to as the first wall portion 143a, and the portion of the first wall portion 143 in the negative X-axis direction with respect to the intersection portion 145 is also referred to as the first wall portion 143b. The portion of the second wall portion 144 in the negative Y-axis direction with respect to the intersection portion 145 is also referred to as the second wall portion 144a, and the portion of the second wall portion 144 in the positive Y-axis direction with respect to the intersection portion 145 is also referred to as the second wall portion 144b. That is, the first wall portion 143 includes the intersection portion 145, the first wall portion 143a, and the first wall portion 143b. The second wall portion 144 includes the intersection portion 145, the second wall portion 144a, and the second wall portion 144b.

[0053] The first member 130 includes an opposing portion 131, a first adjacent portion 132, and a second adjacent portion 133. The opposing portion 131 is a portion of the first member 130 that opposes the position where the first wall portion 143 and the second wall portion 144 of the second member 140 overlap. That is, the opposing portion 131 is a portion that opposes the intersection portion 145 of the second member 140.

[0054] The first adjacent portion 132 is a portion of the first member 130 that is adjacent to the opposing portion 131 in the X-axis direction (second direction) and faces the first wall portion 143. The first adjacent portion 132 is a portion that faces a portion of the first wall portion 143 adjacent to the intersection portion 145. Hereinafter, the portion of the first adjacent portion 132 that faces the first wall portion 143a is also referred to as the first adjacent portion 132a, and the portion that faces the first wall portion 143b is also referred to as the first adjacent portion 132b. The first adjacent portion 132a is adjacent to the opposing portion 131 in the positive X-axis direction and faces the negative X-axis direction end portion of the first wall portion 143a. The first adjacent portion 132b is adjacent to the opposing portion 131 in the negative X-axis direction and faces the positive X-axis direction end portion of the first wall portion 143b.

[0055] The second adjacent portion 133 is a portion of the first member 130 that is adjacent to the opposing portion 131 in the Y-axis direction (third direction) and faces the second wall portion 144. The second adjacent portion 133 is a portion that faces a portion of the second wall portion 144 adjacent to the intersection portion 145. Hereinafter, the portion of the second adjacent portion 133 that faces the second wall portion 144a is also referred to as the second adjacent portion 133a, and the portion that faces the second wall portion 144b is also referred to as the second adjacent portion 133b. The second adjacent portion 133a is adjacent to the opposing portion 131 in the negative Y-axis direction and faces the positive Y-axis direction end portion of the second wall portion 144a. The second adjacent portion 133b is adjacent to the opposing portion 131 in the positive Y-axis direction and faces the negative Y-axis direction end portion of the second wall portion 144b.

[0056] The opposing portion 131 is provided with a protruding portion 131a. The protruding portion 131a is a protrusion that protrudes in the +Z-axis direction from the first adjacent portions 132 (132a, 132b) and the second adjacent portions 133 (133a, 133b). The shape of the protruding portion 131a is not particularly limited, but in the present embodiment, it has a circular shape when viewed from the Z-axis direction. The surface of the opposing portion 131 in the -Z-axis direction (the surface opposite to the protruding portion 131a) is a flat surface (plane) (see FIG. 6B). Therefore, the opposing portion 131 is thicker than the first adjacent portion 132 in the Z-axis direction (the first direction) and protrudes in the direction opposite to the second member 140 than the first adjacent portion 132. Further, the opposing portion 131 is thicker than the second adjacent portion 133 in the Z-axis direction (the first direction) and protrudes in the direction opposite to the second member 140 than the second adjacent portion 133.

[0057] The light transmittance of the first member 130 is higher than that of the second member 140. A high light transmittance (also referred to as transmittance) means that when light is irradiated, the ratio of the light passing through is high (it is easy to pass through). In the present embodiment, the light is the laser light used for joining (welding or soldering) the two members (the first member 130 and the second member 140). That is, in the present embodiment, a high light transmittance means that when laser light is irradiated, the ratio of the laser light passing through is high (it is easy to pass through). When the thicknesses of both the first member 130 and the second member 140 are 2 mm, the light transmittance of the first member 130 is preferably 20% or more, more preferably 30% or more, and even more preferably 40% or more. When the thicknesses of both the first member 130 and the second member 140 are 2 mm, the light transmittance of the second member 140 is preferably 30% or less, more preferably 20% or less, and even more preferably 10% or less. The light transmittance is measured by "transmitted energy (W)" / "irradiated energy (W)" × 100 using a power meter corresponding to the wavelength of the irradiated light.

[0058] The light absorption rate of the second member 140 is higher than that of the first member 130. A high light absorption rate (also referred to as absorbance) means that when irradiated with light such as laser light, the proportion of the light absorbed is high. That is, when the first member 130 and the second member 140 are irradiated with light such as laser light, the second member 140 is more likely to melt than the first member 130. When the thicknesses of both the first member 130 and the second member 140 are 2 mm, the light absorption rate of the first member 130 is preferably 80% or less, more preferably 70% or less, and even more preferably 60% or less. When the thicknesses of both the first member 130 and the second member 140 are 2 mm, the light absorption rate of the second member 140 is preferably 70% or more, more preferably 80% or more, and even more preferably 90% or more. The light absorption rate is measured by "absorbed energy (W)" / "irradiated energy (W)" × 100, similar to the transmittance.

[0059] The materials of the first member 130 and the second member 140 are not particularly limited as long as the first member 130 has a higher light transmittance than the second member 140 and the second member 140 has a higher light absorption rate than the first member 130. As described later, as long as light such as laser light passes through the first member 130 and the second member 140 is melted by irradiating the second member 140 with the light, enabling the first member 130 and the second member 140 to be joined, the materials are not particularly limited. The above light may be light other than laser light such as an electron beam. In this case, the materials of the first member 130 and the second member 140 are appropriately changed according to the type of the light.

[0060] In such a configuration, by irradiating the first member 130 with light such as laser light, the first member 130 and the second member 140 are joined in the Z-axis direction (first direction). The joining configuration of the first member 130 and the second member 140 will be described in detail below.

[0061] First, as shown in FIGS. 6A and 6B, the first member 130 is overlapped with the second member 140. Specifically, the first adjacent portions 132 (132a, 132b) and the opposing portion 131 are arranged in contact with the first wall portion 143 (the first wall portions 143a, 143b and the intersection portion 145). The second adjacent portions 133 (133a, 133b) and the opposing portion 131 are arranged in contact with the second wall portion 144 (the second wall portions 144a, 144b and the intersection portion 145).

[0062] Next, as shown in FIGS. 7A and 7B, the second adjacent portions 133 (133a, 133b) and the opposing portion 131 of the first member 130 are joined to the second wall portion 144 (the second wall portions 144a, 144b and the intersection portion 145) of the second member 140. By irradiating the second adjacent portions 133 and the opposing portion 131 with laser light, the second adjacent portions 133 and the opposing portion 131 and the second wall portion 144 are joined by welding, and the joining portions 170 (171 and 172) are formed.

[0063] Specifically, the second adjacent portions 133 and the opposing portion 131 are arranged on the second wall portion 144 and are pressed and brought into close contact with the second wall portion 144 by a jig (not shown). In this state, laser light is irradiated to the second adjacent portions 133 and the opposing portion 131. Since the second adjacent portions 133 and the opposing portion 131 have a higher light transmittance than the second wall portion 144, the laser light passes through the second adjacent portions 133 and the opposing portion 131 and is irradiated to the second wall portion 144. Since the second wall portion 144 has a higher light absorption rate than the second adjacent portions 133 and the opposing portion 131, the irradiated portion is heated and melted when irradiated with laser light. When the second wall portion 144 melts, the heat is transferred and the second adjacent portions 133 and the opposing portion 131 also melt. As a result, a joining portion 171 in which the melted portions of the second adjacent portions 133a and 133b and the second wall portions 144a and 144b are cooled and joined by welding is formed. A joining portion 172 in which the melted portion of the opposing portion 131 and the intersection portion 145 is cooled and joined by welding is formed.

[0064] When the joints 171 and 172 are formed, since the molten part shrinks, the second adjacent parts 133 and the opposing part 131 sink toward the second wall part 144. In contrast, since the first adjacent part 132 (132a and 132b) does not sink toward the first wall part 143 (143a and 143b), as shown in FIG. 7B, the X-axis direction end of the first adjacent part 132 is lifted in a direction away from the first wall part 143. That is, when the joint 172 is formed and the opposing part 131 sinks toward the intersection part 145, the first adjacent parts 132a and 132b are stretched. As a result, the X-axis plus direction end of the first adjacent part 132a is lifted in the Z-axis plus direction, and the X-axis minus direction end of the first adjacent part 132b is lifted in the Z-axis plus direction.

[0065] Therefore, as shown in FIG. 8A, the jig 2 presses and adheres the first adjacent part 132 to the first wall part 143. That is, the jig 2 presses the X-axis plus direction end of the first adjacent part 132a and the X-axis minus direction end of the first adjacent part 132b against the first wall part 143 with a pressing force F1. At this time, since the protruding part 131a is provided on the opposing part 131, the jig 2 presses the protruding part 131a of the opposing part 131 against the intersection part 145 with the pressing force F1. As a result, the jig 2 can press and adhere the first adjacent parts 132a, 132b and the opposing part 131 to the first wall part 143.

[0066] In this state, as shown in FIG. 8B, the first adjacent portion 132 (132a and 132b) of the first member 130 is joined to the first wall portion 143 (143a and 143b) of the second member 140. By irradiating the first adjacent portion 132 with laser light, the first adjacent portion 132 and the first wall portion 143 are joined by welding, and a joint portion 170 (173) is formed. That is, since the first adjacent portion 132 has a higher light transmittance than the first wall portion 143, the laser light passes through (transmits through) the first adjacent portion 132 and is irradiated onto the first wall portion 143. Since the first wall portion 143 has a higher light absorption rate than the first adjacent portion 132, the portion irradiated by the laser light is heated and melted. When the first wall portion 143 melts, its heat is transferred and the first adjacent portion 132 also melts. As a result, a joint portion 173 is formed in which the melted portion of the first adjacent portion 132 and the first wall portion 143 is cooled and joined by welding. When forming the joint portion 173, the joint portion 172 may be irradiated with laser light again to rejoin the opposing portion 131 and the intersecting portion 145.

[0067] In this way, as shown in FIG. 9, the first member 130 (the first adjacent portion 132, the second adjacent portion 133, and the opposing portion 131) and the second member 140 (the second wall portion 144 and the first wall portion 143) are joined, and a joint portion 170 (171 to 173) is formed.

[0068] [Description of Effects] As described above, according to the power storage device 1 according to the embodiment of the present invention, the second wall portion 144 of the second member 140 is joined to the first member 130, and the first member 130 includes an opposing portion 131 that faces the position where the first wall portion 143 and the second wall portion 144 overlap, and a first adjacent portion 132 that is adjacent to the opposing portion 131 and faces the first wall portion 143. In this configuration, when the second wall portion 144 is joined to the first member 130, the position where the first wall portion 143 and the second wall portion 144 overlap may be recessed more than other portions of the first wall portion 143, causing the opposing portion 131 to lift off from the second member 140. This will be described with reference to FIG. 10. FIG. 10 is a diagram for explaining the effects exhibited by the power storage device 1 according to the present embodiment. FIG. 10 corresponds to FIG. 8A and is a cross-sectional view showing the configuration when the protruding portion 131a is not provided on the opposing portion 131 of the first member 130.

[0069] As described with reference to FIG. 7B, when the joint portion 172 is formed and the opposing portion 131 sinks toward the intersection portion 145, the end portion of the first adjacent portion 132a in the positive X-axis direction is lifted in the positive Z-axis direction, and the end portion of the first adjacent portion 132b in the negative X-axis direction is lifted in the positive Z-axis direction. In this state, a restoring force in the positive Z-axis direction is generated in the opposing portion 131, causing the opposing portion 131 to lift off from the second member 140. For this reason, similar to FIG. 8A, it is conceivable to press the end portions of the first adjacent portions 132a and 132b in the X-axis direction against the first wall portion 143 by the jig 2. However, as shown in FIG. 10, when the end portions of the first adjacent portions 132a and 132b in the X-axis direction are pressed against the first wall portion 143 with a pressing force F1 by the jig 2, a restoring force F2 in the positive Z-axis direction is generated in the opposing portion 131. As a result, the opposing portion 131 lifts off from the second member 140. In this case, a gap (whitening phenomenon) is generated between the opposing portion 131 and the second member 140, and there is a risk that the joint quality between the first member 130 and the second member 140 deteriorates, such as an airtightness defect or a decrease in joint strength between the first member 130 and the second member 140.

[0070] Therefore, according to the power storage device 1, the protruding portion 131a is provided on the opposing portion 131. The opposing portion 131 is thicker than the first adjacent portion 132 and protrudes in a direction opposite to the second member 140 with respect to the first adjacent portion 132. As a result, the first member 130 can be pressed against the second member 140 at the position of the opposing portion 131, so that it is possible to suppress the opposing portion 131 from rising from the second member 140 (the restoring force for the opposing portion 131 to separate from the second member 140 is relaxed). Therefore, it is possible to suppress the generation of a gap (whitening phenomenon) between the opposing portion 131 and the second member 140, and thus it is possible to suppress the deterioration of the bonding quality between the first member 130 and the second member 140 due to the generation of the gap. Further, when the joint portion 173 is formed, the first adjacent portion 132 sinks toward the first wall portion 143, so that the restoring force for the opposing portion 131 to separate from the second member 140 is relaxed.

[0071] In the first member 130, the opposing portion 131 is thicker than the second adjacent portion 133 and protrudes in a direction opposite to the second member 140 with respect to the second adjacent portion 133. As a result, the first member 130 can be more reliably pressed against the second member 140 at the position of the opposing portion 131, so that it is possible to more effectively suppress the opposing portion 131 from rising from the second member 140. By forming the second adjacent portion 133 thinner than the opposing portion 131, the joining operation between the second adjacent portion 133 and the second wall portion 144 can be facilitated. By forming the second adjacent portion 133 thinner than the opposing portion 131, space saving can be achieved. By forming the second adjacent portion 133 thinner than the opposing portion 131, the material usage amount of the first member 130 can be reduced.

[0072] Since the light transmittance of the first member 130 is higher than that of the second member 140 and the light absorption rate of the second member 140 is higher than that of the first member 130, light such as laser light can be transmitted through the first member 130 to join the first member 130 and the second member 140. At this time, when the first member 130 and the second wall portion 144 of the second member 140 are joined, the position where the first wall portion 143 and the second wall portion 144 overlap may melt and become concave compared to other portions of the first wall portion 143. Even in this case, since the first member 130 can be pressed against the second member 140 at the position of the facing portion 131, it is possible to suppress the facing portion 131 from lifting off the second member 140.

[0073] Since the first member 130 and the second member 140 are two members included in the case 10 that houses the power storage element 20, it is possible to suppress a decrease in the joining quality when manufacturing the case 10.

[0074] [Description of Modification 5] As described above, the power storage device 1 according to the present embodiment has been described, but the present invention is not limited to the above embodiment. The embodiments disclosed this time are illustrative in all respects and not restrictive, and the scope of the present invention includes all modifications within the meaning and scope equivalent to the claims.

[0075] (Modifications 1 and 2) In the above embodiment, the first wall portion 143 and the second wall portion 144 of the second member 140 intersect in an X shape, but the present invention is not limited to this. FIG. 11A is a perspective view showing the configuration of the first wall portion 143 and the second wall portion 144 included in the second member 140A according to Modification 1 of the present embodiment. FIG. 11B is a perspective view showing the configuration of the first wall portion 143 and the second wall portion 144 included in the second member 140B according to Modification 2 of the present embodiment. FIGS. 11A and 11B are diagrams corresponding to FIG. 9.

[0076] As shown in Fig. 11A, the second wall portion 144 of the second member 140A in Modification 1 does not include the second wall portion 144b. That is, the second wall portion 144 has a configuration that protrudes from one surface of the first wall portion 143. In this way, the first wall portion 143 and the second wall portion 144 of the second member 140A intersect in a T-shape. Since other configurations of this modification are the same as those in the above embodiment, detailed description thereof is omitted.

[0077] As shown in Fig. 11B, the first wall portion 143 of the second member 140B in Modification 2 does not include the first wall portion 143b. That is, the first wall portion 143 has a configuration that protrudes from one surface of the second wall portion 144. In this way, the first wall portion 143 and the second wall portion 144 of the second member 140B intersect in a T-shape. Since other configurations of this modification are the same as those in the above embodiment, detailed description thereof is omitted.

[0078] As described above, according to Modifications 1 and 2, the same effects as those in the above embodiment are achieved. As in Modifications 1 and 2, the first wall portion 143 and the second wall portion 144 only need to have an intersection portion 145 by intersecting (overlapping), and they may intersect (overlap) in any form.

[0079] (Modifications 3 and 4) In the above-described embodiment, the protruding portion 131a is provided on the opposing portion 131 of the first member 130, but the present invention is not limited to this. FIG. 12 is a perspective view showing the first member 130A and the second member 140 according to Modification Example 3 of the present embodiment. FIG. 12 is a figure corresponding to FIG. 5. FIG. 13A is a perspective view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment is overlaid on the second member 140. FIG. 13A is a figure corresponding to FIG. 6A. FIG. 13B is a cross-sectional view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment is overlaid on the second member 140. FIG. 13B shows a cross-section when the configuration of FIG. 13A is cut by a plane parallel to the YZ plane passing through the XIII B-XIII B line. FIG. 14A is a perspective view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment and the second wall portion 144 of the second member 140 are joined. FIG. 14A is a figure corresponding to FIG. 7A. FIG. 14B is a cross-sectional view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment and the second wall portion 144 of the second member 140 are joined. FIG. 14B shows a cross-section when the configuration of FIG. 14A is cut by a plane parallel to the YZ plane passing through the XIV B-XIV B line. FIG. 15A is a perspective view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment and the second member 140 (the first wall portion 143 and the second wall portion 144) are joined. FIG. 15A is a figure corresponding to FIG. 9. FIG. 15B is a cross-sectional view showing a configuration in a state where the first member 130A according to Modification Example 3 of the present embodiment and the second member 140 (the first wall portion 143 and the second wall portion 144) are joined. FIG. 15B shows a cross-section when the configuration of FIG. 15A is cut by a plane parallel to the YZ plane passing through the XV B-XV B line. FIG. 16 is a perspective view showing the first member 130B and the second member 140C according to Modification Example 4 of the present embodiment. FIG. 16 is a figure corresponding to FIG. 12.

[0080] First, with reference to FIGS. 12 to 15B, Modification 3 will be described in detail. As shown in FIG. 12, the second member 140 includes, in the same manner as in the above-described embodiment, a first wall portion 143 and a second wall portion 144, which are two wall portions extending in two directions orthogonal to the Z-axis direction (first direction), namely, the X-axis direction (second direction) and the Y-axis direction (third direction). The first wall portion 143 includes a first wall portion 143a and 143b and an intersection portion 145. The second wall portion 144 includes a second wall portion 144a and 144b and an intersection portion 145. The first member 130A includes, in the same manner as in the above-described embodiment, an opposing portion 131, a first adjacent portion 132 (132a and 132b), and a second adjacent portion 133 (133a and 133b). The opposing portion 131 faces the position (intersection portion 145) where the first wall portion 143 and the second wall portion 144 overlap. The first adjacent portion 132 (132a and 132b) is adjacent to the opposing portion 131 in the X-axis direction (second direction) and faces the first wall portion 143 (143a and 143b). The second adjacent portion 133 (133a and 133b) is adjacent to the opposing portion 131 in the Y-axis direction (third direction) and faces the second wall portion 144 (144a and 144b). The light transmittance of the first member 130A is higher than that of the second member 140. The light absorption rate of the second member 140 is higher than that of the first member 130A.

[0081] In at least one of the first member 130A and the second member 140, at least one of a first concave portion in which the surface of the first adjacent portion 132 facing the first wall portion 143 is recessed more than the surface of the second adjacent portion 133 facing the second wall portion 144, and a second concave portion in which the surface of the first wall portion 143 facing the first adjacent portion 132 is recessed more than the surface of the second wall portion 144 facing the second adjacent portion 133 is formed. At least one of the first concave portion and the second concave portion is a part of a concave portion extending in the X-axis direction (second direction) formed in at least one of the first member 130A and the second member 140. In Modification 3, in the first member 130A, a first concave portion 134b is formed in which the surface of the first adjacent portion 132 facing the first wall portion 143 is recessed more than the surface of the second adjacent portion 133 facing the second wall portion 144. The first concave portion 134b is a part of a concave portion 134 extending in the X-axis direction (second direction) formed in the first member 130A.

[0082] Specifically, the concave portion 134 is disposed at a position facing the first wall portion 143, and is a concave portion in which the surface of the first member 130A in the negative Z-axis direction is recessed in the positive Z-axis direction. The width of the concave portion 134 in the Y-axis direction is larger than the width of the first wall portion 143 in the Y-axis direction. The concave portion disposed at the position of the opposing portion 131 in the concave portion 134 is referred to as the opposing portion concave portion 134a, and the concave portion disposed at the position of the first adjacent portions 132 (132a and 132b) is referred to as the first concave portion 134b. Since other configurations of this modification are the same as those of the above-described embodiment, detailed description thereof will be omitted.

[0083] In such a configuration, when the first member 130A is irradiated with light such as laser light, the first member 130A and the second member 140 are joined in the Z-axis direction (first direction). The joining configuration of the first member 130A and the second member 140 will be described in detail below.

[0084] First, as shown in FIGS. 13A and 13B, the first member 130A is overlaid on the second member 140. Specifically, the second adjacent portions 133 (133a, 133b) are disposed in contact with the second wall portion 144 (144a, 144b). Since the concave portion 134 is formed in the first member 130A, the first wall portion 143 (the first wall portions 143a, 143b, and the intersection portion 145), and the first adjacent portions 132 (132a, 132b) and the opposing portion 131 do not come into contact.

[0085] Next, as shown in FIGS. 14A and 14B, the second adjacent portions 133 (133a, 133b) of the first member 130A are joined to the second wall portion 144 (144a, 144b) of the second member 140. By irradiating the second adjacent portion 133 with laser light, the second adjacent portion 133 and the second wall portion 14 are joined by welding, and a joining portion 170 (174) is formed.

[0086] When the joint portion 174 is formed, since the molten portion shrinks, the second adjacent portion 133 sinks toward the second wall portion 144. As a result, as shown in FIG. 14B, the opposing portion 131 approaches the intersection portion 145. That is, by disposing the first wall portion 143 within the concave portion 134, the opposing portion 131 and the first adjacent portion 132 approach the first wall portion 143. At this time, it is preferable that the opposing portion 131 and the first adjacent portion 132 contact (adhere to) the first wall portion 143. For this reason, the depth (depth in the Z-axis direction) of the concave portion 134 (the opposing portion concave portion 134a, the first concave portion 134b) is preferably the same as or smaller than the distance by which the opposing portion 131 and the first adjacent portion 132 approach the first wall portion 143 when the joint portion 174 is formed.

[0087] Next, as shown in FIGS. 15A and 15B, the first adjacent portion 132 (132a, 132b) and the opposing portion 131 of the first member 130A are joined to the first wall portion 143 (the first wall portions 143a, 143b and the intersection portion 145) of the second member 140. By irradiating the first adjacent portion 132 and the opposing portion 131 with laser light, the first adjacent portion 132 and the opposing portion 131 and the first wall portion 143 are joined by welding, and a joint portion 170 (175) is formed. In this way, the first member 130A (the first adjacent portion 132, the second adjacent portion 133 and the opposing portion 131) and the second member 140 (the second wall portion 144 and the first wall portion 143) are joined, and a joint portion 170 (174 and 175) is formed.

[0088] Next, Modification 4 will be described. As shown in FIG. 16, in Modification 4, no concave portion is formed in the first member 130B, and a concave portion is formed in the second member 140C. Specifically, in the second member 140C, a second concave portion 143c is formed in a surface facing the first adjacent portion 132 of the first wall portion 143 and recessed more than a surface facing the second adjacent portion 133 of the second wall portion 144. The second concave portion 143c is a part of a concave portion 143d extending in the X-axis direction (second direction) formed in the second member 140C. The concave portion 143d is a concave portion formed on the first wall portion 143 because the height of the first wall portion 143 is lower than the height of the second wall portion 144. The concave portion 143d is disposed at a position facing the opposing portion 131 and the first adjacent portion 132 (132a, 132b). Among the concave portion 143d, the concave portion on the intersection portion 145 is referred to as an intersection concave portion 145a, and the concave portion on the first wall portion 143 (143a, 143b) is referred to as a second concave portion 143c. In such a configuration, when the first member 130B is irradiated with light such as laser light, the first member 130B and the second member 140C are joined in the Z-axis direction (first direction). Since other configurations of this modification are the same as those of Modification 3 described above, detailed description thereof is omitted. The joining configuration between the first member 130B and the second member 140C is also the same as that of Modification 3 described above.

[0089] As described above, at least one of the first member and the second member is formed with at least one of the first concave portion 134b in Modification 3 and the second concave portion 143c in Modification 4. At least one of the first concave portion 134b and the second concave portion 143c is a part of a concave portion extending in the X-axis direction (second direction) formed in at least one of the first member and the second member. The first concave portion 134b and the second concave portion 143c may be formed in both the first member and the second member.

[0090] As described above, according to Modifications 3 and 4, the same effects as those of the above-described embodiment are achieved. In Modifications 3 and 4, similar to the above-described embodiment, the second wall portion 144 is joined to the first member. The first member includes an opposing portion 131 that faces the position where the first wall portion 143 and the second wall portion 144 overlap, a first adjacent portion 132 that is adjacent to the opposing portion 131 and faces the first wall portion 143, and a second adjacent portion 133 that is adjacent to the opposing portion 131 and faces the second wall portion 144. In this configuration, when the second wall portion 144 is joined to the first member, the opposing portion 131 may lift off from the second member due to, for example, the position where the first wall portion 143 and the second wall portion 144 overlap being recessed more than other portions of the first wall portion 143. Specifically, it is as described in the above-described embodiment. In this case, a gap is generated between the opposing portion 131 and the second member, and there is a risk that the joining quality between the first member and the second member deteriorates, such as an airtightness defect or a decrease in joining strength between the first member and the second member.

[0091] Therefore, in Modifications 3 and 4, at least one of the first member and the second member is formed with at least one of a first recess 134b in which the surface of the first adjacent portion 132 is recessed more than the surface of the second adjacent portion 133, and a second recess 143c in which the surface of the first wall portion 143 is recessed more than the surface of the second wall portion 144. Thereby, even when the second adjacent portion 133 sinks toward the second wall portion 144 when joining the second adjacent portion 133 and the second wall portion 144, the other can be disposed within at least one of the recesses of the first adjacent portion 132 and the first wall portion 143, so that the opposing portion 131 can be suppressed from lifting off from the second member. Therefore, the generation of a gap (whitening phenomenon) between the opposing portion 131 and the second member can be suppressed, and thus the deterioration of the joining quality between the first member and the second member due to the generation of the gap can be suppressed. Even when the depth (width in the Z-axis direction) of the first recess 134b or the second recess 143c is small, when joining the first adjacent portion 132 and the first wall portion 143, the first adjacent portion 132 sinks toward the first wall portion 143, so that the opposing portion 131 can be suppressed from lifting off from the second member.

[0092] At least one of the first recess 134b and the second recess 143c is a part of a recess extending in the X-axis direction (second direction) formed in at least one of the first member and the second member. Thereby, since the other is disposed in the recess extending in the X-axis direction (second direction) of at least one of the first adjacent portion 132 and the first wall portion 143, it becomes easier to bring the opposing portion 131 closer to the position where the first wall portion 143 and the second wall portion 144 overlap, and thus it is possible to more effectively suppress the opposing portion 131 from lifting off the second member. By forming a recess extending in the X-axis direction (second direction) in the first member or the second member and making a part thereof the first recess 134b or the second recess 143c, the first recess 134b or the second recess 143c can be easily formed.

[0093] In the above Modification 3, it is sufficient that the first recess 134b is formed in the first member 130A, and the opposing portion recess 134a may not be formed. The first recess 134b may be formed only at one of the positions of the first adjacent portions 132a and 132b. In the above Modification 4, it is sufficient that the second recess 143c is formed in the second member 140C, and the intersecting portion recess 145a may not be formed. The second recess 143c may be formed only at one of the positions of the first wall portions 143a and 143b.

[0094] (Other Modifications) In the above embodiment, the small lid of the case lid 100 was described with the first member 130 and the main body of the case lid 100 as the second member 140, but the small lid of the case lid 100 may have the same configuration as the second member 140, and the main body of the case lid 100 may have the same configuration as the first member 130. That is, the small lid of the case lid 100 may include wall portions similar to the first wall portion 143 and the second wall portion 144 and may be joined to a portion having the same configuration as the first member 130 in the main body of the case lid 100.

[0095] In the above embodiment, in the case lid 100, the joint portion between the first member 130 and the second member 140 has the above configuration, but the joint portion between the third member 150 and the second member 140 may have the above configuration.

[0096] In the above embodiment, the case lid 100 is provided with the first member 130 and the second member 140. However, the case body 200 may be provided with a portion having the same configuration as the first member 130 and the second member 140. One of the case lid 100 and the case body 200 may be provided with a portion having the same configuration as the first member 130, and the other may be provided with a portion having the same configuration as the second member 140. That is, when the case 10 is composed of two or more members, any two of the two or more members may be provided with portions having the same configuration as the first member 130 and the second member 140. Alternatively, any two members other than the case 10 included in the power storage device 1 may be provided with portions having the same configuration as the first member 130 and the second member 140. The two members may be the container body 21a and the container lid portion 21b of the container 21 of the power storage element 20, or the spacer between the power storage elements 20 and the case 10, or the spacer and the holding member 40, or the case 10 and the holding member 40, or any other two members. Regarding the material, the two members may be a resin member and a metal member, or a metal member and a resin member, or a metal member and a metal member.

[0097] In the above embodiment, the first member 130 and the second member 140 are joined by irradiating light such as laser light. However, the joining method is not particularly limited. In the above embodiment, the joining portion between the first member 130 and the second wall portion 144 is melted by irradiating light such as laser light, and the opposing portion 131 rises from the second member 140. However, as long as the opposing portion 131 rises from the second member 140, it may be joined by any method. If the first member 130 and the second wall portion 144 are joined by thermal welding or ultrasonic welding or the like and the opposing portion 131 rises from the second member 140, it may be joined by thermal welding or ultrasonic welding or the like. The same applies to other joining methods. In such a case, the light transmittance of the first member 130 does not have to be higher than the light transmittance of the second member 140, and the light absorption rate of the second member 140 does not have to be higher than the light absorption rate of the first member 130.

[0098] In the above embodiment, the first member 130 is joined to the first wall portion 143, but it may not be joined to the first wall portion 143. Even in this case, since the first member 130 is joined to the second wall portion 144, there is a possibility that the facing portion 131 may lift off from the second member 140. Therefore, by pressing the first member 130 against the second member 140 at the position of the facing portion 131, it is possible to suppress the facing portion 131 from lifting off from the second member 140.

[0099] In the above embodiment, the first wall portion 143 and the second wall portion 144 of the second member 140 extend in the second direction and the third direction (X-axis direction and Y-axis direction), which are two orthogonal directions. However, the second direction and the third direction are not limited to being orthogonal, and they may intersect. That is, the first wall portion 143 and the second wall portion 144 may extend in two intersecting directions (two different directions).

[0100] In the above embodiment, the opposing portion 131 is thicker than both the first adjacent portions 132a and 132b in the Z-axis direction and protrudes in the direction opposite to the second member 140 compared to both the first adjacent portions 132a and 132b. However, the present invention is not limited to this. The opposing portion 131 may be thicker than either one of the first adjacent portions 132a and 132b in the Z-axis direction, or may protrude in the direction opposite to the second member 140 compared to either one of the first adjacent portions 132a and 132b. Similarly, the opposing portion 131 may be thicker than either one of the second adjacent portions 133a and 133b in the Z-axis direction, or may protrude in the direction opposite to the second member 140 compared to either one of the second adjacent portions 133a and 133b. Or, the opposing portion 131 may not be thicker than both the second adjacent portions 133a and 133b in the Z-axis direction, or may not protrude in the direction opposite to the second member 140 compared to both the second adjacent portions 133a and 133b. That is, the protruding portion 131a may be a protruding portion extending in the Y-axis direction that straddles the opposing portion 131 and the second adjacent portion 133. Even with these, by pressing the first member 130 against the second member 140 at the position of the opposing portion 131, it is possible to suppress the opposing portion 131 from lifting off the second member 140.

[0101] In the above embodiment, the protruding portion 131a may be a portion that leaves the resin injection port (gate) when the first member 130 is resin-molded without cutting it, or may be any other protruding portion.

[0102] Each modification example of the above embodiment may be applied to the above modification examples 1 to 4. The above modification example 3 or 4 may be applied to the above modification example 1 or 2. In addition, a form constructed by arbitrarily combining the constituent elements included in the above embodiment and its modification examples is also included within the scope of the present invention.

Industrial Applicability

[0103] The present invention can be applied to a power storage device including a power storage element such as a lithium ion secondary battery.

Explanation of Reference Numerals

[0104] 1 Battery device 2 Fixture 10 Case 20 Energy storage element 30, 31, 32, 33, 60, 61, 62, 111, 121 Bus bar 100 Case lid 110, 120 External terminal 130, 130A, 130B First member 131 Opposite part 131a Protrusion 132, 132a, 132b First adjacent part 133, 133a, 133b Second adjacent part 134, 143d Recess 134a Opposite part recess 134b First recess 140, 140A, 140B, 140C Second member 141, 146 Opening 142, 147 Wall part 143, 143a, 143b First wall part 143c Second recess 144, 144a, 144b Second wall part 145 Intersection part 145a Intersection part recess 150 Third member 160 Exhaust part 161 Wiring holding part 170, 171, 172, 173, 174, 175 Joint part 200 Case body

Claims

1. A power storage device including a power storage element, comprising a first member and a second member joined in a first direction, wherein the second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, namely a second direction and a third direction, the second wall portion is joined to the first member, the first member includes a facing portion facing a position where the first wall portion and the second wall portion overlap, and a first adjacent portion adjacent to the facing portion in the second direction and facing the first wall portion, wherein the facing portion is thicker than the first adjacent portion in the first direction and protrudes in a direction opposite to the second member with respect to the first adjacent portion power storage device.

2. The first member further includes a second adjacent portion adjacent to the facing portion in the third direction, wherein the facing portion is thicker than the second adjacent portion in the first direction and protrudes in a direction opposite to the second member with respect to the second adjacent portion The power storage device according to claim 1.

3. A power storage device including a power storage element, comprising a first member and a second member joined in a first direction, wherein the second member includes a first wall portion and a second wall portion which are two wall portions extending in two directions orthogonal to the first direction, namely a second direction and a third direction, the second wall portion is joined to the first member, the first member includes a facing portion facing a position where the first wall portion and the second wall portion overlap, a first adjacent portion adjacent to the facing portion in the second direction and facing the first wall portion, and a second adjacent portion adjacent to the facing portion in the third direction and facing the second wall portion, wherein at least one of the first member and the second member is formed with at least one of a first recess in which a surface of the first adjacent portion facing the first wall portion is recessed more than a surface of the second adjacent portion facing the second wall portion, and a second recess in which a surface of the first wall portion facing the first adjacent portion is recessed more than a surface of the second wall portion facing the second adjacent portion power storage device.

4. At least one of the first recess and the second recess is part of a recess extending in the second direction formed in at least one of the first member and the second member The power storage device according to claim 3.

5. The light transmittance of the first member is higher than the light transmittance of the second member, and the light absorption rate of the second member is higher than the light absorption rate of the first member The power storage device according to any one of claims 1 to 4.

6. The first member and the second member are two members included in a case that houses the power storage element. The power storage device according to any one of claims 1 to 4.

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