Electric energy storage device

Abstract

To provide a power storage device capable of suppressing damage to a power storage element.SOLUTION: A power storage device 10 includes a power storage element 300, and an end plate 400 arranged side by side with the power storage element 300 in the first direction, and an exterior body 11 in which the power storage element 300 and the end plate 400 are accommodated, and the exterior body 11 includes a first wall portion 110 at a position sandwiching the end plate 400 with the power storage element 300, and the first wall portion 110 has one side in a second direction that intersects the first direction, which has a larger distance with the power storage element 300 in the first direction than the other side, the end plate 400 has a second portion 420 having a larger width in the first direction on one side in the second direction than a first portion 410 on the other side in the second direction. The second portion 420 is an integrally formed portion, and has a shape in which a plurality of portions on one side of the end plate 400 in the second direction are overlapped in the first direction, or a shape in which a portion of the end plate 400 on one side in the second direction is bent in the first direction.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a power storage device including a power storage element, an end plate, and an exterior body.

Background Art

[0002] Conventionally, a power storage device including a power storage element and an end plate, with the power storage element and the end plate housed in an exterior body, has been widely known. For example, Patent Document 1 discloses a power storage device in which a pair of end plates are arranged on both sides of a plurality of power storage elements, and these are housed in an exterior body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a power storage device configured as described above in the related art, if a gap is generated between the power storage element and the exterior body, the power storage element may be damaged. For example, when processing the exterior body, a configuration may be formed in which a gap is generated between the exterior body and the power storage element (such as a draft when the exterior body is a resin molded product), or due to the structural relationship with a member outside the power storage device, the exterior body may be intentionally configured to have a gap with the power storage element (such as a design with a narrower bottom). In this case, if an end plate is arranged between the power storage element and the exterior body, a gap may occur between the power storage element or the exterior body and the end plate, that is, in the portion where a gap is generated between the power storage element and the exterior body. When such a gap occurs, the fixing of the power storage element in the exterior body may become insufficient, or the end plate may not sufficiently suppress the swelling of the power storage element, making the power storage element prone to deformation, and there is a risk that the power storage element may be damaged.

[0005] The present invention has been made by the inventors of the present application newly focusing on the above problems, and an object thereof is to provide a power storage device capable of suppressing damage to a power storage element.

Means for Solving the Problems

[0006] In order to achieve the above object, a power storage device according to an aspect of the present invention is a power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, wherein the exterior body has a wall portion at a position where the end plate is sandwiched between the power storage element, and the wall portion has a greater distance from the power storage element in the first direction on one side in a second direction intersecting the first direction than on the other side, the end plate has a second portion on one side in the second direction, the width of which in the first direction is greater than that of a first portion on the other side in the second direction, the second portion is an integrally formed part, and has a shape in which parts of the end plate on one side in the second direction overlap in the first direction, or a shape in which parts of the end plate on one side in the second direction are bent in the first direction.

[0007] According to this, in the power storage device, in the wall portion of the exterior body, the distance from the power storage element in the first direction is greater on one side in the second direction than on the other side, and the end plate has a second portion on one side in the second direction that is wider in the first direction than the first portion on the other side. In this way, by forming the second portion with a larger width on the side where the distance between the power storage element and the wall portion of the exterior body is large in the end plate, the gap in the first direction between the power storage element, the wall portion of the exterior body, and the end plate can be reduced, and the occurrence of such a gap can be suppressed. Thereby, the occurrence of a gap between the power storage element and the wall portion of the exterior body can be suppressed, so that the swelling of the power storage element can be suppressed and the damage of the power storage element can be suppressed. In particular, the second portion is an integrally formed part, and has a shape in which a plurality of portions on one side in the second direction of the end plate overlap or a bent shape. In this way, by making the second portion an integrally formed and simple configuration such as an overlapping or bent shape of a plurality, the second portion can be easily formed on the end plate. By these, in the power storage device, the damage of the power storage element can be easily suppressed.

[0008] The power storage element may have a container, and a joint portion may be formed on one side in the second direction of the container.

[0009] According to this, since the joint portion is formed on one side in the second direction of the container of the power storage element, the joint portion vicinity of the container of the power storage element can be directly or indirectly pressed by the second portion of the end plate. In the power storage element, when the container swells, the joint portion may be damaged, but by pressing the vicinity of the joint portion with the second portion, the joint portion can be reinforced, so that the damage of the joint portion when the container swells can be suppressed. Thereby, the damage of the power storage element can be suppressed.

[0010] The second portion may be arranged in the second direction between the joint portion and the central position of the container, and at a position where the distance from the joint portion is smaller than the distance from the central position of the container.

[0011] According to this, by arranging the second part of the end plate between the joint of the container of the power storage element and the center position of the container, and at a position where the distance from the joint is smaller than the distance from the center position of the container, the second part can press a position closer to the joint on the center side of the container than the joint. As a result, the joint can be further strengthened, so that damage to the joint when the container bulges can be more effectively suppressed.

[0012] The second part may be arranged to protrude toward the power storage element.

[0013] According to this, since the second part of the end plate protrudes toward the power storage element, the second part can effectively press the power storage element, so that the swelling of the power storage element can be effectively suppressed. As a result, damage to the power storage element can be suppressed.

[0014] The first part may be arranged to protrude toward the central part of the power storage element in the second direction.

[0015] According to this, since the first part of the end plate protrudes toward the central part of the power storage element, the central part of the power storage element can be effectively pressed. Generally, the central part of the power storage element bulges, but if the central part of the power storage element can be effectively pressed, the swelling of the central part of the power storage element can be more effectively suppressed. As a result, damage to the power storage element can be suppressed.

[0016] The present invention can be realized not only as such a power storage device, but also as an end plate or a combination of an end plate and an exterior body.

Advantages of the Invention

[0017] According to the power storage device of the present invention, damage to the power storage element can be suppressed.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

MODE FOR CARRYING OUT THE INVENTION

[0019] Hereinafter, with reference to the drawings, a power storage device according to an embodiment (including its modification examples) of the present invention will be described. Note that each of the embodiments described below shows a comprehensive or specific example. 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 merely examples and are not intended to limit the present invention. In each figure, dimensions and the like are not strictly illustrated. In each figure, the same or similar components are denoted by the same reference numerals.

[0020] In the following description and drawings, the arrangement direction of a plurality of power storage elements, the arrangement direction of a pair of end plates, the arrangement direction of a power storage element and an end plate, the facing direction of a pair of long side surfaces in the container of one power storage element, or the thickness direction of a power storage element or an end plate is defined as the X-axis direction. The arrangement direction of a pair of electrode terminals in one power storage element, or the facing 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 of the exterior body and the exterior body lid of the power storage device, the arrangement direction of the main body of the container and the container lid of one power storage element, the arrangement direction of the power storage element and the bus bar, 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 convenience of explanation, the Z-axis direction will be described as the vertical direction.

[0021] In the following description, for example, the X-axis plus direction indicates the arrow direction of the X-axis, and the X-axis minus direction indicates the direction opposite to the X-axis plus direction. The same applies to the Y-axis direction and the Z-axis direction. Hereinafter, the X-axis direction may also be referred to as the first direction, the Z-axis direction may also be referred to as the second direction, the Z-axis plus direction may also be referred to as one side of the second direction, and the Z-axis minus direction may also be referred to as the other side of the second direction. Expressions indicating relative directions or postures such as parallel and orthogonal strictly include cases where they are not in that direction or posture. For example, when two directions are orthogonal, it means not only that the two directions are completely orthogonal, but also that they are substantially orthogonal, that is, for example, including a difference of about several percent. Further, in the following description, when the expression "insulation" is used, it means "electrical insulation".

[0022] (Embodiment) [1 General description of the power storage device 10] First, the configuration of the power storage device 10 will be described. FIG. 1 is a perspective view showing the appearance of the power storage device 10 according to the present embodiment. FIG. 2 is an exploded perspective view showing each component when the power storage device 10 according to the present embodiment is disassembled.

[0023] The power storage device 10 is a device that can charge electricity from the outside and discharge electricity to the outside, and in this embodiment, it has a substantially rectangular parallelepiped shape. For example, the power storage device 10 is a battery module (battery pack) used for power storage applications or power supply applications, etc. Specifically, the power storage device 10 is used, for example, 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, or a railway vehicle for electric railways, or for engine starting. Examples of the above-mentioned automobiles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and gasoline vehicles. 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 10 can also be used as a stationary battery for household or business use, etc.

[0024] As shown in FIG. 1, the power storage device 10 includes an exterior body 11. As shown in FIG. 2, inside the exterior body 11, a plurality of power storage elements 300, a pair of end plates 400, and a plurality of bus bars 500 are accommodated. In addition to the above components, the power storage device 10 may include a bus bar frame for positioning the bus bar 500, a spacer disposed between the power storage elements 300 or between the power storage element 300 and the end plate 400, a circuit board for monitoring the charge state and discharge state of the power storage element 300, and electrical devices such as relays. An adhesive or the like may be disposed between the power storage elements 300 and between the power storage element 300 and the end plate 400 so that they are adhered and fixed.

[0025] The exterior body 11 is a box-shaped (substantially rectangular parallelepiped-shaped) container (module case) that constitutes the housing (outer shell) of the power storage device 10. That is, the exterior body 11 is disposed outside a plurality of power storage elements 300, a pair of end plates 400, and a plurality of bus bars 500, fixes these power storage elements 300, etc. at predetermined positions, and protects them from impacts and the like. The exterior body 11 is formed of an insulating member such as, for example, polycarbonate (PC), polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polyphenylene ether (PPE (including modified PPE)), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyether ether ketone (PEEK), tetrafluoroethylene·perfluoroalkyl vinyl ether (PFA), polytetrafluoroethylene (PTFE), polyethersulfone (PES), ABS resin, or a composite material thereof. Thereby, the exterior body 11 avoids the power storage elements 300, etc. from coming into contact with external metal members, etc. Note that the exterior body 11 may be formed of a conductive member such as metal as long as the insulation of the power storage elements 300, etc. is maintained.

[0026] The exterior body 11 has an exterior body main body 100 that constitutes the main body of the exterior body 11 and an exterior body lid 200 that constitutes the lid of the exterior body 11. The exterior body main body 100 is a bottomed rectangular cylindrical housing (case) in which an opening facing in the positive Z-axis direction is formed, and houses the power storage elements 300, etc. The exterior body main body 100 has a pair of first wall portions 110 facing each other on the side surfaces on both sides in the X-axis direction, a pair of second wall portions 120 facing each other on the side surfaces on both sides in the Y-axis direction, and a third wall portion 130 on the negative Z-axis direction side.

[0027] The first wall portion 110 is a rectangular and flat wall portion (short side wall portion) that forms the short side surface of the exterior body 11, and is arranged to face the end plate 400 in the X-axis direction. That is, the first wall portion 110 is arranged at a position where the end plate 400 is sandwiched between the first wall portion 110 and the power storage element 300. The first wall portion 110 is adjacent to the second wall portion 120 and the third wall portion 130, and has a smaller outer surface area than the second wall portion 120. The second wall portion 120 is a rectangular and flat wall portion (long side wall portion) that forms the long side surface of the exterior body 11, and is arranged to face the short side surface portion 312 of a container 310 (to be described later) of the power storage element 300 in the Y-axis direction. The second wall portion 120 is adjacent to the first wall portion 110 and the third wall portion 130, and has a larger outer surface area than the first wall portion 110. The third wall portion 130 is a rectangular and flat wall portion (bottom wall portion) that forms the bottom surface of the exterior body 11, and is arranged to face the bottom surface portion 313 of the container 310 (to be described later) of the power storage element 300 in the Z-axis direction. The third wall portion 130 is adjacent to the first wall portion 110 and the second wall portion 120. Note that depending on the number, shape, etc. of the power storage elements 300, the first wall portion 110 may be a long side wall portion and the second wall portion 120 may be a short side wall portion.

[0028] The exterior body lid 200 is a flat rectangular member that is joined to the exterior body main body 100 by an adhesive, heat sealing, ultrasonic welding, or the like to close the opening of the exterior body main body 100. A pair of external terminals 210 (a positive electrode external terminal and a negative electrode external terminal) are provided on the exterior body lid 200. The power storage device 10 charges electricity from the outside and discharges electricity to the outside via this pair of external terminals 210. The exterior body main body 100 and the exterior body lid 200 may be formed of members of the same material or members of different materials.

[0029] The energy storage element 300 is a secondary battery (single cell) that can charge and discharge electricity. More specifically, it is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 300 has a flat rectangular parallelepiped shape (rectangular shape). In the present embodiment, eight energy storage elements 300 are arranged side by side in the X-axis direction (first direction). Note that the shape of the energy storage element 300 is not limited to a rectangular parallelepiped shape, and may be an oval cylinder shape, an elliptical cylinder shape, a cylinder shape, or a polygonal prism shape other than a rectangular parallelepiped. The number of energy storage elements 300 to be arranged is not particularly limited, and only one energy storage element 300 may be arranged. The energy storage element 300 is not limited to a non-aqueous electrolyte secondary battery, and may be a secondary battery other than a non-aqueous electrolyte secondary battery, or may be a capacitor. The energy storage element 300 may be a primary battery in which the electricity stored without the user charging can be used instead of a secondary battery. The energy storage element 300 may be a battery using a solid electrolyte. The energy storage element 300 may be a pouch-type energy storage element. A detailed description of the configuration of the energy storage element 300 will be given later.

[0030] The end plate 400 is a flat plate-shaped and rectangular member (clamping member) arranged side by side with the energy storage element 300 in the X-axis direction (first direction). Specifically, a pair of end plates 400 are arranged on both sides in the X-axis direction of a plurality of energy storage elements 300, and the plurality of energy storage elements 300 are sandwiched and held from both sides in the arrangement direction (X-axis direction) of the plurality of energy storage elements 300. Thereby, the pair of end plates 400 compress the plurality of energy storage elements 300 from both sides in their arrangement direction (X-axis direction). The end plate 400 is formed of a metal (conductive) material such as stainless steel, iron, plated steel sheet, aluminum, or aluminum alloy, for example, from the viewpoint of ensuring strength. Note that the material of the end plate 400 is not particularly limited, and it may be formed of, for example, a highly strong insulating material, or may be subjected to an insulation treatment. A detailed description of the configuration of the end plate 400 will be given later.

[0031] The bus bar 500 is a flat and rectangular member that is disposed above the plurality of power storage elements 300 and is connected to electrode terminals 340 (a positive electrode terminal and a negative electrode terminal) of the plurality of power storage elements 300, which will be described later. Thereby, the bus bar 500 connects the electrode terminals 340 of the plurality of power storage elements 300 to each other, and connects the electrode terminal 340 of the power storage element 300 at the end and the external terminal 210 via another bus bar (not shown). The bus bar 500 is formed of a metal conductive member such as, for example, aluminum, an aluminum alloy, copper, or a copper alloy. In the present embodiment, the bus bar 500 connects two power storage elements 300 in parallel to form four sets of power storage element groups, and connects the four sets of power storage element groups in series, but the connection form of the power storage elements 300 is not particularly limited.

[0032] [Description of the two power storage elements 300] Next, the configuration of the power storage element 300 will be described in detail. Since all of the plurality of power storage elements 300 included in the power storage device 10 have the same configuration, the configuration of one power storage element 300 will be described in detail below. FIG. 3 is a perspective view showing the configuration of the power storage element 300 according to the present embodiment. Specifically, FIG. 3 shows the internal configuration of the container 310 of the power storage element 300 in a perspective view through the container 310.

[0033] As shown in FIG. 3, the power storage element 300 includes a container 310 and a pair of electrode terminals 340 (a positive electrode side and a negative electrode side). Inside the container 310, an electrode body 350 and a pair of current collectors 360 (a positive electrode side and a negative electrode side) are accommodated. An electrolytic solution (non-aqueous electrolyte) is also enclosed inside the container 310, and a gasket is disposed between the electrode terminal 340 and the current collector 360 and the container 310 (container lid body 330, which will be described later), but detailed descriptions thereof are omitted. The type of the electrolytic solution is not particularly limited as long as it does not impair the performance of the power storage element 300, and various types can be selected.

[0034] In addition to the above-described components, the energy storage element 300 may have a spacer disposed on the side or below the electrode body 350, and an insulating film or the like that wraps the electrode body 350 and the like. Further, an insulating film (such as a shrink tube) that covers the outer surface of the container 310 may be disposed around the container 310. The material of the insulating film is not particularly limited as long as it can ensure the insulation required for the energy storage element 300. Examples thereof include insulating resins such as PC, PP, PE, PPS, PET, PBT, or ABS resin, epoxy resin, Kapton, Teflon (registered trademark), silicon, polyisoprene, and polyvinyl chloride.

[0035] The container 310 is a rectangular parallelepiped (square or box-shaped) case having a container body 320 with an opening formed therein and a container lid 330 that closes the opening of the container body 320. The container body 320 is a rectangular cylindrical member with a bottom that constitutes the main body of the container 310, and an opening is formed on the +Z-axis direction side. The container lid 330 is a rectangular plate-like member that constitutes the lid portion of the container 310, and is disposed to extend in the Y-axis direction in the +Z-axis direction of the container body 320. The container lid 330 is provided with a gas discharge valve 331 that releases the pressure when the pressure inside the container 310 rises, and a liquid injection portion (not shown) for injecting an electrolytic solution into the container 310. The material of the container 310 (the container body 320 and the container lid 330) is not particularly limited, and can be, for example, a weldable (joinable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel sheet, but a resin can also be used.

[0036] After the electrode body 350 and the like are housed inside the container body 320, the container 310 has a structure in which the container body 320 and the container lid 330 are joined by welding or the like to form a joint portion 310a, and the inside is sealed. For example, laser light is irradiated from the side (X-axis direction and Y-axis direction) of the container 310, and the container body 320 and the container lid 330 are joined by laser welding to form the joint portion 310a. The joint portion 310a is a square annular joint portion formed so as to surround the periphery (entire circumference) of the container 310.

[0037] With such a configuration, the container 310 has a pair of long side portions 311 on the side surfaces on both sides in the X-axis direction, a pair of short side portions 312 on the side surfaces on both sides in the Y-axis direction, and a bottom portion 313 on the Z-axis minus direction side. The long side portion 311 is a rectangular flat portion forming the long side surface of the container 310, and is arranged to face the long side portion 311 of the container 310 of the adjacent power storage elements 300 or the end plate 400 in the X-axis direction. The long side portion 311 is adjacent to the short side portion 312 and the bottom portion 313, and has a larger area than the short side portion 312. The short side portion 312 is a rectangular flat portion forming the short side surface of the container 310, and is arranged to face the second wall portion 120 of the exterior body 11 in the Y-axis direction. The short side portion 312 is adjacent to the long side portion 311 and the bottom portion 313, and has a smaller area than the long side portion 311. The bottom portion 313 is a rectangular flat portion forming the bottom surface of the container 310, and faces the third wall portion 130 of the exterior body 11 in the Z-axis direction and is arranged adjacent to the long side portion 311 and the short side portion 312.

[0038] The electrode terminal 340 is a terminal member (positive electrode terminal and negative electrode terminal) of the power storage element 300 disposed on the container lid 330, and is electrically connected to the positive electrode plate and the negative electrode plate of the electrode body 350 via the current collector 360. That is, the electrode terminal 340 is a metal member for leading out the electricity stored in the electrode body 350 to the external space of the power storage element 300 and introducing electricity into the internal space of the power storage element 300 to store electricity in the electrode body 350. The electrode terminal 340 is formed of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

[0039] The electrode body 350 is a power storage element (power generation element) that can store electricity, and includes a positive electrode plate, a negative electrode plate, and a separator, and is formed by laminating the positive electrode plate, the negative electrode plate, and the separator. The positive electrode plate is an electrode plate in which a positive electrode active material layer is formed on a positive electrode base material layer that is a strip-shaped current collector foil made of a metal such as aluminum or an aluminum alloy. The negative electrode plate is an electrode plate in which a negative electrode active material layer is formed on a negative electrode base material layer that is a strip-shaped current collector foil made of a metal such as copper or a copper alloy. The separator is a microporous sheet made of resin. As the positive electrode active material used in the positive electrode active material layer and the negative electrode active material used in the negative electrode active material layer, any known material can be appropriately used as long as it can occlude and release lithium ions. For the separator as well, any known material can be appropriately used as long as it does not impair the performance of the power storage element 300.

[0040] In the present embodiment, the electrode body 350 is a so-called longitudinally wound wound-type electrode body formed by winding a layered structure in which a separator is sandwiched between a positive electrode plate and a negative electrode plate. Specifically, in the electrode body 350, the positive electrode plate and the negative electrode plate are wound with a shift in the direction of the winding axis (Y-axis direction) via a separator. And the positive electrode plate and the negative electrode plate have a portion (a non-forming portion of the composite material layer) where the composite material is not coated and the base material layer is exposed (the composite material layer is not formed) at the end portions 351 in the shifted directions. The electrode body 350 is electrically and mechanically connected to the current collector 360 at the end portion 351. Note that the electrode body 350 may be a so-called laterally wound wound-type formed by winding the positive electrode plate, the negative electrode plate, and the separator in the lateral direction (winding with a winding axis parallel to the Z-axis direction). Also, the electrode body 350 may be an electrode body of any form such as a laminated type (stack type) electrode body formed by laminating a plurality of flat plate-shaped electrode plates, or a bellows type electrode body in which the electrode plates are folded in a bellows shape.

[0041] The current collector 360 is a member that is disposed between the electrode body 350 and the side wall of the container 310 and has conductivity and rigidity for being electrically connected to the electrode terminal 340 and the electrode body 350. The current collector 360 is joined to the end portion 351 of the electrode body 350 by welding or the like. The current collector 360 on the positive electrode side is formed of aluminum or an aluminum alloy, similar to the positive electrode base material layer of the positive electrode plate of the electrode body 350, and the current collector 360 on the negative electrode side is formed of copper or a copper alloy, similar to the negative electrode base material layer of the negative electrode plate of the electrode body 350.

[0042] [Description of the 3 end plate 400] Next, the configuration of the end plate 400 will be described in detail. FIG. 4 is a side view showing the configuration in a state where the end plate 400 according to the present embodiment is attached to the power storage element 300 and housed in the exterior body main body 100 of the exterior body 11. Note that FIG. 4 shows the configuration when the exterior body main body 100, the power storage element 300, and the end plate 400 are viewed from the negative Y-axis direction, and the exterior body main body 100 shows a cross section cut by a plane parallel to the XZ plane.

[0043] As shown in FIG. 4, in the exterior body 11, the first wall portion 110 of the exterior body main body 100 is formed such that the distance from the power storage element 300 in the X-axis direction (first direction) is larger on the positive Z-axis direction (one side of the second direction intersecting the first direction) than on the negative Z-axis direction (the other side of the second direction). That is, the first wall portion 110 is disposed to be inclined in a direction away from the power storage element 300 as it goes in the positive Z-axis direction. The first wall portion 110 in the positive X-axis direction is inclined in the positive X-axis direction as it goes in the positive Z-axis direction, and the first wall portion 110 in the negative X-axis direction is inclined in the negative X-axis direction as it goes in the positive Z-axis direction. In other words, the exterior body main body 100 is formed such that the interval between the pair of first wall portions 110 increases as it goes in the positive Z-axis direction from the third wall portion 130. For example, when processing the exterior body main body 100, the opening side of the exterior body main body 100 is formed wide by forming a draft for removing the mold or the like.

[0044] The end plate 400 is formed to have the same length as the long side surface portion 311 of the container 310 of the power storage element 300 in the Y-axis direction and the Z-axis direction, and is a member that covers the entire long side surface portion 311. As shown in FIGS. 2 and 4, the end plate 400 has a first portion 410 in the Z-axis minus direction (the other side of the second direction) and a second portion 420 in the Z-axis plus direction (one side of the second direction). The first portion 410 is a flat plate-shaped and rectangular portion parallel to the YZ plane extending in the Y-axis direction and the Z-axis direction. The second portion 420 is a flat plate-shaped and rectangular portion parallel to the YZ plane extending in the Y-axis direction and the Z-axis direction, and has a larger width (the dimension of the width in the X-axis direction) in the X-axis direction (the first direction) than the first portion 410 in the Z-axis minus direction (the other side of the second direction). That is, the second portion 420 is a wide portion with a larger distance between both end edges in the X-axis direction than the first portion 410.

[0045] The width of the second portion 420 in the X-axis direction (the first direction) is the distance in the X-axis direction between the edge most in the X-axis minus direction and the edge most in the X-axis plus direction among the second portion 420. That is, the width of the second portion 420 in the X-axis direction (the first direction) is the dimension in the X-axis direction occupied by the entire second portion 420, and in this embodiment, it is the thickness (plate thickness) of the second portion 420. The same applies to the width of the first portion 410 in the X-axis direction (the first direction).

[0046] Specifically, the second portion 420 has a shape in which the portions of the end plate 400 in the Z-axis plus direction (one side of the second direction) are overlapped in the X-axis direction, or a shape in which the portions of the end plate 400 in the Z-axis plus direction (one side of the second direction) are bent in the X-axis direction. In this embodiment, the second portion 420 has a shape in which the portions of the end plate 400 in the Z-axis plus direction are overlapped in the X-axis direction. The first portion 410 is a non-overlapping portion of the end plate 400. For example, by overlapping two plate-shaped members having the same length in the Y-axis direction and different lengths in the Z-axis direction in the X-axis direction so that the end edges in the Z-axis plus direction are aligned, the thin (non-overlapping) first portion 410 located in the Z-axis minus direction and the thick (overlapping) second portion 420 located in the Z-axis plus direction are formed.

[0047] As a result, the second part 420 has a shape that protrudes from the first part 410 toward the first wall portion 110 of the exterior body main body 100. In the end plate 400 in the positive X-axis direction, the second part 420 protrudes from the first part 410 in the positive X-axis direction, and in the end plate 400 in the negative X-axis direction, the second part 420 protrudes from the first part 410 in the negative X-axis direction. That is, the surface of the end plate 400 facing the power storage element 300 is a flat plane, and the surface facing the first wall portion 110 is a stepped surface where the portion in the positive Z-axis direction protrudes toward the first wall portion 110.

[0048] With such a configuration, in the end plate 400, between the long side surface portion 311 of the container 310 of the power storage element 300 and the first wall portion 110, both the first part 410 and the second part 420 are in contact with the long side surface portion 311, and the second part 420 is in contact with the first wall portion 110. That is, in at least a part of the second part 420, the power storage element 300 and the end plate 400 are in contact, and the end plate 400 and the first wall portion 110 are in contact. In the present embodiment, the end portion of the second part 420 in the negative Z-axis direction is in contact with the first wall portion 110, but by being formed in a shape along the first wall portion 110, it may be in contact with the first wall portion 110 from one end to the other end of the second part 420 in the Z-axis direction. Regarding the first part 410 as well, it may be formed such that the end portion in the negative Z-axis direction or other portions are in contact with the first wall portion 110.

[0049] The second part 420 is an integrally formed part. That is, the two plate-like members are joined (fixed) in a superimposed state to form the integrated second part 420. For example, the two plate-like members are joined by ultrasonic bonding, laser welding or welding such as resistance welding, adhesion by an adhesive or double-sided tape, or mechanical joining such as caulking or bolt fastening, whereby the second part 420 is formed. Thereby, the end plate 400 becomes one member in which the integrated second part 420 and the first part 410 are integrated. Note that an end plate 400 in which a thin integrated first part 410 and a thick integrated second part 420 are integrated may be formed by superimposing and joining (fixing) three or more plate-like members in the X-axis direction.

[0050] As described above, the bonding portion 310a is formed in the +Z-axis direction (one side of the second direction) of the container 310 of the power storage element 300. That is, the bonding portion 310a of the power storage element 300 is formed on the side where the distance between the first wall portion 110 and the power storage element 300 in the exterior body main body 100 is large. At least a part of the second part 420 is arranged in the Z-axis direction (second direction) between the bonding portion 310a and the central position of the container 310, and at a position where the distance from the bonding portion 310a is smaller than the distance from the central position of the container 310. Specifically, the second part 420 is arranged in contact with the long side surface portion 311 from the end portion in the +Z-axis direction of the container 310 of the power storage element 300 to a position closer to the +Z-axis direction in the central portion in the Z-axis direction. Thereby, the second part 420 is arranged across the bonding portion 310a so as to cover the bonding portion 310a on the long side surface portion 311 side.

[0051] [Description of effects] As described above, according to the power storage device 10 according to the present embodiment, in the first wall portion 110 of the exterior body 11, the distance from the power storage element 300 in the first direction (X-axis direction) is formed to be larger on one side (Z-axis positive direction) in the second direction than on the other side (Z-axis negative direction). The end plate 400 has a second portion 420 whose width in the first direction is larger than that of the first portion 410 on the other side in the second direction. For example, when the exterior body 11 is resin-molded, there may be a configuration in which a gap is formed between the exterior body 11 and the power storage element 300 due to a draft or the like. Depending on the structural relationship with members outside the power storage device 10, there may be a case where the exterior body 11 is intentionally configured to have a gap with the power storage element 300, such as by designing the third wall portion 130 (bottom wall portion) of the exterior body 11 to be narrow. Therefore, in the end plate 400, by forming the second portion 420 with a larger width on the side where the distance between the power storage element 300 and the first wall portion 110 of the exterior body 11 is large, the gap in the first direction between the power storage element 300 and the first wall portion 110 of the exterior body 11 and the end plate 400 can be reduced, and the occurrence of such a gap can be suppressed. As a result, the occurrence of a gap between the power storage element 300 and the first wall portion 110 of the exterior body 11 can be suppressed, so that the swelling of the power storage element 300 can be suppressed and the damage to the power storage element 300 can be suppressed. In particular, the second portion 420 is an integrally formed portion and has a shape in which a plurality of portions on one side in the second direction of the end plate 400 overlap. In this way, by making the second portion 420 have a simple configuration of being integrally formed and having a shape in which a plurality of portions overlap, the second portion 420 can be easily formed on the end plate 400. Thus, in the power storage device 10, the damage to the power storage element 300 can be easily suppressed.

[0052] Since the joint portion 310a is formed on one side (the +Z-axis direction) in the second direction of the container 310 of the energy storage element 300, in the second portion 420 of the end plate 400, the joint portion 310a of the container 310 of the energy storage element 300 and the vicinity thereof can be directly or indirectly (directly in this embodiment) pressed. In the energy storage element 300, when the container 310 bulges, the joint portion 310a may be damaged. Specifically, when the container 310 bulges, stress is applied to the joint portion 310a (welded portion), and the joint portion 310a may be peeled off. On the other hand, by pressing the joint portion 310a and the vicinity thereof with the second portion 420, the joint portion 310a can be reinforced, so that damage to the joint portion 310a when the container 310 bulges can be suppressed. Thereby, damage to the energy storage element 300 can be suppressed.

[0053] At least a part of the second portion 420 of the end plate 400 is arranged between the joint portion 310a of the container 310 of the energy storage element 300 and the central position of the container 310, and at a position where the distance from the joint portion 310a is smaller than the distance from the central position of the container 310. Thereby, with the second portion 420, a position closer to the joint portion 310a on the central side of the container 310 than the joint portion 310a can be pressed. Thereby, the joint portion 310a can be further reinforced, so that damage to the joint portion 310a when the container 310 bulges can be more effectively suppressed.

[0054] Note that the power storage device 10 includes a pair of end plates 400 in the +X-axis direction and the -X-axis direction, and the above effects can be said for both of the pair of end plates 400.

[0055] [Description of Modification Example 5] (Modification Example 1) Next, Modification Example 1 of the above embodiment will be described. FIG. 5 is a side view showing the configuration of the end plate 400a according to Modification Example 1 of the present embodiment. Note that FIG. 5 corresponds to the portion at the end in the +X-axis direction of FIG. 4.

[0056] As shown in FIG. 5, in this modified example, instead of the end plate 400 in the above embodiment, an end plate 400a is arranged. The end plate 400a has a second part 420a instead of the second part 420 of the end plate 400. Since the other configurations are the same as those in the above embodiment, detailed descriptions thereof are omitted.

[0057] Similar to the second part 420 in the above embodiment, the second part 420a is a flat and rectangular part parallel to the YZ plane. The parts of the end plate 400a in the positive Z-axis direction overlap in the X-axis direction, so that the width in the X-axis direction is formed to be larger than that of the first part 410. Different from the second part 420 in the above embodiment, the second part 420a is an integrally formed part by bending the parts of the end plate 400a in the positive Z-axis direction. That is, the end plate 400a is a single member in which the first part 410 and the second part 420a are formed by bending and overlapping the parts of a single plate-like member in the positive Z-axis direction by press forming or the like. Note that the overlapping parts in the second part 420a may be joined to each other by welding or the like, or may not be joined only by bending.

[0058] As described above, according to the power storage device according to this modified example, the same effects as those in the above embodiment can be achieved. In particular, in this modified example, since the second part 420a can be formed by bending a single plate-like member, the end plate 400a can be easily manufactured.

[0059] (Modified Example 2) Next, a second modified example of the above embodiment will be described. FIG. 6 is a side view showing the configuration of an end plate 400c according to the second modified example of the present embodiment. Note that FIG. 6 corresponds to the part at the end in the positive X-axis direction of FIG. 4.

[0060] As shown in FIG. 6, in this modified example, an end plate 400c is disposed instead of the end plate 400 in the above-described embodiment. The end plate 400c has a first part 410c and a second part 420c instead of the first part 410 and the second part 420 of the end plate 400. Since the other configurations are the same as those in the above-described embodiment, detailed description thereof will be omitted.

[0061] The first part 410c is a flat and rectangular part that abuts against the first wall part 110 along the first wall part 110 of the exterior body main body 100. The first part 410c occupies most of the end plate 400c. The second part 420c is a part of the end plate 400c other than the first part 410c, and is an end part of the end plate 400c in the +Z axis direction. The second part 420c has a shape in which a part of the end plate 400c in the +Z axis direction (one side of the second direction) is bent in the X axis direction (the first direction), so that the width in the X axis direction (the first direction) is formed to be larger than that of the first part 410c.

[0062] The width of the second part 420c in the X axis direction (the first direction) is the distance in the X axis direction between the edge most in the -X axis direction and the edge most in the +X axis direction of the second part 420c. That is, the width of the second part 420c in the X axis direction (the first direction) is not the plate thickness of the second part 420c, but the dimension in the X axis direction occupied by the entire second part 420c (the dimension including the gap part). The same applies to the width of the first part 410c in the X axis direction (the first direction).

[0063] The second part 420c is a curved plate-shaped part with a semi-circular shape where the end of the end plate 400c in the positive Z-axis direction is curved in the negative X-axis direction, positive Z-axis direction, and positive X-axis direction in order from the first part 410c. The second part 420c is a wide, integrally formed part with a larger distance between both end edges in the X-axis direction than the first part 410c. In this way, the end plate 400c is a single member in which the first part 410c and the second part 420c are integrally formed by bending a single plate-shaped member by press forming or the like. Note that the end plate 400c may be formed in a bent shape by casting or forging instead of being bent.

[0064] As a result, the second part 420c is arranged to protrude toward the power storage element 300. Specifically, the second part 420c is arranged at a position between the joint part 310a and the center position of the container 310 in the Z-axis direction (second direction), and at a position where the distance from the joint part 310a is smaller than the distance from the center position of the container 310. That is, the second part 420c abuts on and presses a part slightly below (negative Z-axis direction) the joint part 310a on the long side surface part 311 of the container 310 of the power storage element 300.

[0065] As described above, according to the power storage device according to this modification example, the same effects as those of the above embodiment can be achieved. In particular, in this modification example, the second part 420c is an integrally formed part, and the part on one side (positive Z-axis direction) of the end plate 400c in the second direction has a bent shape and is arranged to protrude toward the power storage element 300. In this way, by making the second part 420c have a simple structure of being integrally formed and having a bent shape, the second part 420c can be easily formed on the end plate 400c. As a result, in the power storage device, damage to the power storage element 300 can be easily suppressed.

[0066] By disposing the second part 420c between the joint part 310a and the central position of the container 310 and at a position where the distance from the joint part 310a is smaller than the distance from the central position of the container 310, the second part 420c can press a position closer to the joint part 310a on the central side of the container 310 than the joint part 310a. Thereby, since the joint part 310a can be reinforced, it is possible to suppress damage to the joint part 310a when the container 310 bulges. Since the second part 420c is disposed so as to protrude toward the power storage element 300, the second part 420c can effectively press the power storage element 300, so that the bulge of the power storage element 300 can be effectively suppressed.

[0067] (Modification 3) Next, Modification 3 of the above-described embodiment will be described. FIG. 7 is a side view showing the configuration of the end plate 400d according to Modification 3 of the present embodiment. Note that FIG. 7 is a figure corresponding to FIG. 6.

[0068] As shown in FIG. 7, in this modification, an end plate 400d is disposed instead of the end plate 400c in Modification 2. The end plate 400d has a first part 410d instead of the first part 410c of the end plate 400c in Modification 2. Since the other configurations are the same as those in Modification 2, detailed description thereof will be omitted.

[0069] The first part 410d is a part that protrudes toward the central part in the Z-axis direction (second direction) of the power storage element 300. That is, in the first part 410d, the part in the minus Z-axis direction from the second part 420c of the end plate 400d protrudes in a curved shape toward the central part in the Z-axis direction of the long side surface part 311 of the container 310 of the power storage element 300. In the Z-axis direction, both ends of the first part 410d are in contact with the first wall part 110 of the exterior body main body 100, and the central part is in contact with the central part of the long side surface part 311. The second part 420c is formed to have a larger width in the X-axis direction (first direction) than the first part 410d. The definition of the width in the X-axis direction (first direction) of the first part 410d and the second part 420c is the same as that in Modification 2.

[0070] As described above, according to the power storage device according to this modification example, the same effects as those of the above-described embodiment and Modification Example 2 can be obtained. In particular, in this modification example, the first portion 410d is arranged to project toward the central portion of the power storage element 300, so that the central portion of the power storage element 300 can be effectively pressed. Generally, the central portion of the power storage element 300 bulges, but if the central portion of the power storage element 300 can be effectively pressed, the bulging of the central portion of the power storage element 300 can be further suppressed. Thereby, damage to the power storage element 300 can be suppressed.

[0071] (Other Modification Examples) As described above, the power storage device according to the present embodiment (including its modification examples) has been described, but the present invention is not limited to the above-described embodiment. That is, the embodiment disclosed this time is illustrative in all respects and not restrictive, and the scope of the present invention includes all changes within the meaning and scope equivalent to the claims.

[0072] For example, in the above-described embodiment, the end plate 400 (including 400a, 400c, and 400d, the same applies hereinafter) covers the entire long side surface portion 311 of the container 310 of the power storage element 300, but is not limited to covering the entire long side surface portion 311. For example, the end plate 400 may be formed shorter than the long side surface portion 311 in the Y-axis direction, or may be formed shorter than the long side surface portion 311 in the Z-axis direction.

[0073] In the above-described embodiment, the +Z-axis direction is one side of the second direction, and the -Z-axis direction is the other side of the second direction, but the -Z-axis direction may be one side of the second direction, and the +Z-axis direction may be the other side of the second direction. That is, the first wall portion 110 has a larger distance from the power storage element 300 at the portion in the -Z-axis direction than at the portion in the +Z-axis direction, and the second portion 420 (including 420a to 420c, the same applies hereinafter) may be arranged in the -Z-axis direction of the end plate 400.

[0074] In the above embodiment, the joint portion 310a is formed at the end portion of the container 310 of the power storage element 300 in the +Z-axis direction. However, the joint portion 310a may be formed at the end portion of the container 310 in the -Z-axis direction, or may be formed at other positions.

[0075] In the above embodiment, the second portion 420 may be arranged at a position between the joint portion 310a and the central position of the container 310, where the distance from the joint portion 310a is greater than the distance from the central position of the container 310. The second portion 420 may not be arranged between the joint portion 310a and the central position of the container 310. In the above Modifications 2 and 3, the second portion 420c may be arranged to protrude toward the first wall portion 110. In the above Modification 3, the first portion 410d may be arranged to protrude toward the end portion of the power storage element 300, or may be arranged to protrude toward the first wall portion 110. Thus, various shapes can be applied as the end plate 400.

[0076] In the above embodiment, it is assumed that both of the pair of end plates 400 have the above configuration. However, it is not necessary for either one of the end plates 400 to have the above configuration.

[0077] A form constructed by arbitrarily combining the respective components included in the above embodiment and its modifications is also included within the scope of the present invention.

[0078] The present invention can be realized not only as such a power storage device, but also as an end plate, or a combination of an end plate and an exterior body.

Industrial Applicability

[0079] 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

[0080] 10 Power storage device 11 Exterior body 100 Exterior body main body 110 First wall portion 120 Second wall portion 130 Third wall portion 200 Exterior body cover 210 External terminal 300 Energy storage element 310 Container 310a Joint portion 311 Long side face portion 312 Short side face portion 313 Bottom face portion 320 Container body 330 Container cover 331 Gas discharge valve 340 Electrode terminal 350 Electrode body 351 End portion 360 Current collector 400, 400a, 400c, 400d End plate 410, 410c, 410d First part 420, 420a, 420c Second part 500 Bus bar

Claims

1. A power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, wherein the exterior body has a wall portion at a position where the end plate is sandwiched by the power storage element, wherein the distance between the wall portion and the power storage element in the first direction is larger on one side in a second direction intersecting the first direction than on the other side, wherein the end plate has a second portion on one side in the second direction, the width of which in the first direction is larger than that of a first portion on the other side in the second direction, wherein the second portion is an integrally formed part, and a part of the end plate on one side in the second direction has a shape bent in the first direction, a power storage device.

2. A power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, wherein the exterior body has a wall portion at a position where the end plate is sandwiched by the power storage element, wherein the distance between the wall portion and the power storage element in the first direction is larger on one side in a second direction intersecting the first direction than on the other side, wherein the end plate has a second portion on one side in the second direction, the width of which in the first direction is larger than that of a first portion on the other side in the second direction, wherein the second portion is an integrally formed part, and a part of the end plate on one side in the second direction has a shape where a plurality of layers overlap in the first direction, or a shape where a part of the end plate on one side in the second direction is bent in the first direction, wherein the exterior body has a bottom wall portion on the other side in the second direction of the power storage element and the end plate, a power storage device.

3. A power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, wherein the exterior body has a wall portion at a position where the end plate is sandwiched by the power storage element, wherein the distance between the wall portion and the power storage element in the first direction is larger on one side in a second direction intersecting the first direction than on the other side, wherein the end plate has a second portion on one side in the second direction, the width of which in the first direction is larger than that of a first portion on the other side in the second direction, The second part is an integrally formed part, and has a shape in which parts on one side of the end plate in the second direction overlap in the first direction, or a shape in which a part on one side of the end plate in the second direction is bent in the first direction. The power storage element has a container. A joint is formed on one side of the container in the second direction. Power storage device.

4. The second part is arranged in the second direction between the joint and the central position of the container, and at a position where the distance from the joint is smaller than the distance from the central position of the container. The power storage device according to claim 3.

5. A power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, The exterior body has a wall portion at a position where the end plate is sandwiched between the exterior body and the power storage element. On one side in the second direction intersecting the first direction, the wall portion has a greater distance from the power storage element in the first direction than on the other side. The end plate has a second part on one side in the second direction, and the width of the second part in the first direction is greater than that of a first part on the other side in the second direction. The second part is an integrally formed part, and has a shape in which parts on one side of the end plate in the second direction overlap in the first direction, or a shape in which a part on one side of the end plate in the second direction is bent in the first direction. The second part is arranged to protrude toward the power storage element. Power storage device.

6. A power storage device including a power storage element, an end plate arranged side by side with the power storage element in a first direction, and an exterior body that houses the power storage element and the end plate, The exterior body has a wall portion at a position where the end plate is sandwiched between the exterior body and the power storage element. On one side in the second direction intersecting the first direction, the wall portion has a greater distance from the power storage element in the first direction than on the other side. The end plate has a second part on one side in the second direction, and the width of the second part in the first direction is greater than that of a first part on the other side in the second direction. The second part is an integrally formed part, and has a shape in which parts on one side of the end plate in the second direction overlap in the first direction, or a shape in which a part on one side of the end plate in the second direction is bent in the first direction. The first part is disposed to protrude toward the central portion of the power storage element in the second direction. Power storage device.

Images