JP7115013B2 - power storage device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a power storage device including one or more power storage elements and end members arranged at ends of the one or more power storage elements.

Conventionally, a power storage device including one or more power storage elements and end members arranged at ends of the one or more power storage elements is widely known. For example, Patent Literature 1 discloses a power supply device (power storage device) in which end plates (end members) are arranged at both ends of a plurality of batteries (power storage elements) to fix the plurality of batteries.

JP 2010-287514 A

However, there is a problem that the end member may be damaged in the power storage device having the conventional structure. For example, when the electric storage element swells, force is applied to the end member, which may cause damage such as deformation of the end member.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a power storage device capable of suppressing damage to an end member.

To achieve the above object, a power storage device according to an aspect of the present invention includes one or more power storage elements, and the end power storage element positioned at the end of the one or more power storage elements on the first direction side. and an end member disposed on one side, wherein the end member includes a first bulging portion that bulges in the first direction, and the first bulging portion a second bulging portion disposed on the central portion side of the end storage element and bulging in the first direction, wherein the second bulging portion extends in a direction crossing the first direction; A second side wall, which is a side wall of the first bulging portion, is arranged to be more inclined with respect to the first direction than the first side wall, which is a side wall of the first bulging portion in a direction crossing the first direction.

According to this, in the electricity storage device, the end member has the first swelling portion and the second swelling portion closer to the central portion of the end energy storage element than the first swelling portion. The second side wall of the bulging portion is arranged to be more inclined than the first side wall of the first bulging portion. When the power storage element tries to swell, force is applied to the end member, which may cause damage such as deformation of the end member. and the second side wall of the second bulging portion on the central side is arranged to be more inclined than the first side wall of the first bulging portion. Accordingly, even if a force is applied to the end member, the force can be suppressed by the first bulging portion and the second bulging portion, so damage such as deformation of the end member can be suppressed. . In addition, since the end storage element swells more easily on the central side, the end member receives a greater force from the end storage element on the center side of the end storage element. On the other hand, if the side wall of the bulging portion is inclined, deformation when force is applied to the bulging portion can be suppressed. Accordingly, by arranging the second side wall of the second bulging portion to be more inclined than the first side wall of the first bulging portion, deformation of the second bulging portion that receives a large force from the end storage element, etc. Since damage can be suppressed, damage such as deformation of the end member can be suppressed.

The second bulging portion is formed to extend in a second direction that intersects with the first direction, and the second side wall is a side wall of the second bulging portion on the second direction side. You can decide.

According to this, in the end member, the second side wall of the second bulging portion is the side wall on the extension direction side of the second bulging portion. In this way, when the second bulging portion is formed to extend, a large force is applied to the side wall in the extending direction of the second bulging portion when receiving force from the end storage element. For this reason, the side wall on the extending direction side of the second bulging portion is inclined as the second side wall. As a result, damage such as deformation of the second bulging portion can be suppressed, so that damage to the end member can be suppressed.

Further, the second bulging portion has a third side wall that is a side wall in a third direction crossing the first direction and the second direction, and the second side wall is more It may be arranged so as to be inclined with respect to the first direction.

According to this, in the second bulging portion of the end member, the second side wall is arranged more inclined than the third side wall in the direction intersecting with the extending direction of the second bulging portion. Here, in the second bulging portion, the third side wall extends in the extending direction of the second bulging portion and is longer than the second side wall. The area of the surface of the end member facing the element is reduced. Therefore, by making the third side wall less inclined than the second side wall, it is possible to secure the area of the surface of the end member facing the end storage element. As a result, the force from the end power storage element can be received over a wider surface, so damage to the end member can be suppressed.

Further, a side member may be provided on the side of the one or more electric storage elements in a direction crossing the first direction, and the first swelling portion may be fixed to the side member.

According to this, the first swelling portion of the end member is fixed to the side member. Here, since the first side wall of the first bulging portion is not inclined as much as the second side wall of the second bulging portion, if the surface area of the end member facing the end storage element is not changed, the second The first bulging portion can have a larger surface area to be fixed to the side member than the bulging portion. Therefore, by fixing the side member to the first bulging portion, the side member can be more firmly fixed to the end member without reducing the area of the surface of the end member facing the end storage element. . As a result, the end member can be reinforced by the side member while receiving the force from the end power storage element over a wider surface, so that damage to the end member can be further suppressed.

Further, the power storage device includes one or more power storage elements, and an end member arranged on the first direction side of the end power storage element positioned at the end of the one or more power storage elements on the first direction side. The end member has a bulging portion that extends in a second direction that intersects with the first direction and bulges in the first direction, and the bulging portion It has a second side wall that is a side wall in two directions, and a third side wall that is a side wall in a third direction that intersects the first direction and the second direction, and the second side wall is the side wall in the third direction. It may be arranged so as to be inclined with respect to the first direction rather than the side wall.

According to this, in the power storage device, the end member has the bulging portion, and the second side wall of the bulging portion on the side of the extension direction is larger than the third side wall on the side intersecting the extension direction. placed at an angle. Here, in the case where the bulging portion is formed to extend, if a force is received from the end storage element, a large force is applied to the side wall in the extending direction of the bulging portion. I want to incline the second side wall on the installation direction side. In addition, since the third side wall is longer than the second side wall, if the third side wall is inclined, the surface area of the end member facing the end storage element becomes smaller. , do not want to slope as much as the second sidewall. For this reason, the second side wall on the extending direction side of the bulging portion is inclined more than the third side wall. As a result, it is possible to secure the area of the surface of the end member facing the end storage element and to receive the force from the end storage element over a wider surface while suppressing damage such as deformation of the bulging portion. , it is possible to suppress the end member from being damaged.

Further, a method for manufacturing a power storage device according to an aspect of the present invention includes: one or more power storage elements; and forming a bulging portion in the end member by hot press forming to bulge in the first direction. The bulging portion forming step includes a heating step of heating a metal member, and after the heating step, pressing the heated metal member with a mold to form the bulging portion on the metal member. and a pressing step to form a

According to this, the method for manufacturing a power storage device includes a bulging portion forming step of forming a bulging portion in an end member by hot press forming, in the bulging portion forming step, the metal member is heated, and then and forming a bulging portion in the metal member by pressing the heated metal member with a mold. In this way, when the electric storage element tries to swell, force is applied to the end member, and the end member may be deformed or otherwise damaged. Here, since hot press forming is superior in formability to cold press forming and the like, hot press forming can easily form a bulging portion having a depth sufficient to suppress damage to the end member. can be formed. Furthermore, in hot press forming, by heating and pressing a metal member, an end member with high strength can be formed. Thus, the inventors of the present application have found that hot press forming is more suitable than conventional cold press forming or the like in order to form end members having a complicated shape and high strength. Therefore, even if force is applied to the end member, it is possible to easily form an end member that is less likely to be damaged by hot press forming, so that the end member can be prevented from being damaged.

Further, in the pressing step, a first bulging portion that bulges in the first direction and a first bulging portion that is arranged closer to the central portion of the end storage element than the first bulging portion and oriented in the first direction A second side wall, which is a side wall of the second bulging portion in a direction intersecting the first direction, intersects the first direction of the first bulging portion. The bulge is formed so as to be inclined with respect to the first direction from the first side wall, which is a side wall on the side of the bulge, or is formed to extend in a second direction intersecting the first direction. The second side wall, which is the side wall on the second direction side, is more inclined with respect to the first direction than the third side wall, which is the side wall on the side of the third direction that intersects the first direction and the second direction. You may decide to form so that it may incline.

According to this, in the method for manufacturing a power storage device, the first swelling portion and the second swelling portion closer to the central portion of the end storage element than the first swelling portion are arranged at the second swelling portion. The two side walls are formed so as to be more inclined than the first side wall of the first bulging portion, or the bulging portion is formed such that the second side wall in the extending direction is the third side wall in the direction intersecting the extending direction. formed to be more inclined than By forming the second side wall of the second bulging portion to be more inclined than the first side wall of the first bulging portion in this way, the second bulging portion receives a large force from the end storage element. Damage such as deformation can be suppressed. Alternatively, by forming the second side wall on the extending direction side of the bulging portion to be more inclined than the third side wall, the area of the surface of the end member facing the end storage element is secured and widened. Damage such as deformation of the bulging portion can be suppressed while receiving the force from the end storage element on the surface. As a result, damage to the end member can be suppressed. In particular, hot press forming is superior in formability to cold press forming and the like. It is possible to easily form the second side wall on the extending direction side of the bulging portion so as to be inclined more than the third side wall.

The present invention can be realized not only as such a power storage device and a method for manufacturing the power storage device, but also as an end member provided in the power storage device or a method for manufacturing the end member.

According to the power storage device of the present invention, damage to the end member can be suppressed.

1 is a perspective view showing an appearance of a power storage device according to an embodiment; FIG. 1 is a perspective view showing a configuration of an electric storage element according to an embodiment; FIG. It is a perspective view which shows the structure of the end member which concerns on embodiment. FIG. 4 is a cross-sectional view showing the positional relationship among the storage element, the end member, the side member, and the inserted member according to the embodiment; FIG. 4 is a cross-sectional view showing the positional relationship among the storage element, the end member, the side member, and the inserted member according to the embodiment; FIG. 4 is a cross-sectional view showing the positional relationship among the storage element, the end member, the side member, and the inserted member according to the embodiment; FIG. 4 is a cross-sectional view showing the positional relationship among a power storage element, an end member, and a side member according to the embodiment;

Power storage devices according to embodiments of the present invention will be described below with reference to the drawings. It should be noted that the embodiments described below represent comprehensive or specific examples. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, manufacturing processes, order of manufacturing processes, and the like shown in the following embodiments are examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in independent claims representing the highest concept will be described as arbitrary constituent elements. Also, in each drawing, dimensions and the like are not strictly illustrated.

Further, in the following description and drawings, the direction in which a pair of electrode terminals are arranged in one storage element, the direction in which a pair of short side portions of a container of one storage element face each other, the direction in which insulators are arranged, the direction in which side members are arranged, Alternatively, the direction in which the insulators and the side members are arranged is defined as the X-axis direction. Further, the direction in which the energy storage elements are arranged, the direction in which the spacers are arranged, the direction in which the end members are arranged, the direction in which the energy storage elements, the spacers, and the end members are arranged, the direction in which the pair of long side portions of the container of one energy storage element face each other, or The thickness direction of the elements, spacers, or end members is defined as the Y-axis direction. Also, the direction in which the container body and the lid of the storage element are arranged, 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 cross each other (perpendicularly in this embodiment). Although the Z-axis direction may not be the vertical direction depending on the mode of use, the Z-axis direction will be described below for convenience of explanation. Further, in the following description, for example, the positive direction of the X-axis indicates the direction of the arrow of the X-axis, and the negative direction of the X-axis indicates the opposite direction to the positive direction of the X-axis. The same applies to the Y-axis direction and the Z-axis direction.

(Embodiment)
[1 General description of power storage device 10]
First, a schematic configuration of the power storage device 10 will be described. FIG. 1 is a perspective view showing the appearance of power storage device 10 according to the present embodiment.

The power storage device 10 is a device that can charge electricity from the outside and discharge electricity to the outside. For example, the power storage device 10 is a battery module (assembled battery) used for power storage or power supply. Specifically, the power storage device 10 is, for example, an electric vehicle (EV), a hybrid electric vehicle (HEV) or a plug-in hybrid electric vehicle (PHEV) such as an automobile, a motorcycle, a watercraft, a snowmobile, an agricultural machine, a construction It is used as a battery for driving a moving object such as a machine or for starting an engine.

As shown in FIG. 1, the power storage device 10 includes a plurality of (12 in the present embodiment) power storage elements 100, a plurality of (13 in the present embodiment) spacers 200, a pair of end members 300, It has a pair of side members 400 , a pair of insulators 500 and two pairs of inserted members 600 . The power storage device 10 also includes a bus bar that electrically connects the electrode terminals of the plurality of power storage elements 100, a bus bar frame that holds the bus bar, external terminals, and the like. Detailed description is also omitted. In addition, the power storage device 10 includes wiring for voltage measurement of the power storage element 100, wiring for temperature measurement, a thermistor, a circuit board for monitoring the charge/discharge state of the power storage element 100, and electrical equipment such as a relay. may be

The storage element 100 is a secondary battery (single battery) capable of charging and discharging electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium ion secondary battery. . Energy storage element 100 has a flat rectangular parallelepiped (square) shape and is arranged adjacent to spacer 200 . That is, each of the plurality of power storage elements 100 is arranged alternately with each of the plurality of spacers 200 and arranged in the Y-axis direction. In the present embodiment, 12 power storage elements 100 are arranged between adjacent spacers 200 out of 13 spacers 200 .

Here, among the plurality of energy storage elements 100, the energy storage element 100 positioned at the end is also referred to as an end energy storage element 100a. That is, in the present embodiment, two end storage elements 100a are arranged at both ends in the Y-axis direction. In other words, the end power storage element 100a is the power storage element 100 located at the end of the plurality of power storage elements 100 on the Y-axis plus direction side or the Y-axis minus direction side (hereinafter also referred to as the first direction side). .

Here, the first direction is the direction from the energy storage elements 100 other than the end energy storage element 100a toward the end energy storage element 100a. Alternatively, the first direction is the direction in which the long side surface portion (long side surface portion 111a described later) of the end storage element 100a side of the storage element 100 faces, or the opposite side of the end storage element 100a to the storage element 100. can also be said to be the direction in which the long side surface portion 111a of . Note that the number of storage elements 100 is not limited to 12, and may be a plurality other than 12, or may be one. , the one or two storage elements 100 become the end storage elements 100a.

Moreover, the shape of the electric storage element 100 is not limited to a rectangular parallelepiped shape, and may be a polygonal prism shape other than a rectangular parallelepiped shape, or may be a laminated electric storage element. Moreover, the storage element 100 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. Also, the storage device 100 may be a primary battery that allows the stored electricity to be used without being charged by the user, instead of a secondary battery. Furthermore, the storage element 100 may be a battery using a solid electrolyte. A detailed description of the configuration of this storage element 100 will be given later.

Spacer 200 is a rectangular plate-shaped spacer that is arranged on the side of power storage element 100 (Y-axis plus direction or Y-axis minus direction) and insulates power storage element 100 from other members. Specifically, the spacer 200 is arranged between two adjacent energy storage elements 100 and between the end energy storage element 100a and the end member 300, and is arranged between the two energy storage elements 100 and between the end energy storage elements 100a. It is a spacer that insulates between the element 100 a and the end member 300 . The spacer 200 is made of an insulating material such as polycarbonate (PC), polypropylene (PP), polyethylene (PE), polyphenylene sulfide resin (PPS), polyethylene terephthalate (PET), ABS resin, or the like.

Note that the spacer 200 may be joined to the storage element 100 and the end member 300 by placing an adhesive, double-sided tape, or the like on both sides in the Y-axis direction. In addition, in the present embodiment, thirteen (thirteen) spacers 200 are arranged corresponding to twelve power storage elements 100, but when the number of power storage elements 100 is other than twelve, spacers 200 is also changed according to the number of storage elements 100 .

The end member 300 and the side member 400 are members that press the storage elements 100 from the outside in the direction in which the plurality of storage elements 100 are arranged (the Y-axis direction). That is, the end members 300 and the side members 400 sandwich the plurality of power storage elements 100 from both sides in the alignment direction, thereby pressing the power storage elements 100 included in the plurality of power storage elements 100 from both sides in the alignment direction.

Specifically, the end members 300 are arranged on both sides of the plurality of energy storage elements 100 in the Y-axis direction, and sandwich the plurality of energy storage elements 100 from both sides in the direction in which the plurality of energy storage elements 100 are arranged (Y-axis direction). It is a plate-like sandwiching member (end plate) that holds. That is, the end member 300 is a plate-like member arranged on the Y-axis plus direction side or the Y-axis minus direction side (first direction side) of the end storage element 100a. The end member 300 is formed of a metal (conductive) member such as steel or stainless steel from the viewpoint of strength. The material of the end member 300 is not particularly limited, and for example, it may be formed of an insulating member having high strength, or may be subjected to an insulating treatment. A detailed description of the configuration of the end member 300 will be given later.

The side member 400 is an elongated plate-shaped restraining member (side plate) having both ends attached to the end members 300 and restraining the plurality of power storage elements 100 . That is, the side member 400 is arranged so as to extend in the Y-axis direction so as to straddle the plurality of power storage elements 100 and the plurality of spacers 200 , and the side members 400 are aligned with respect to the plurality of power storage elements 100 and the plurality of spacers 200 . A constraint force is applied in the direction (Y-axis direction). In the present embodiment, two side members 400 are arranged on both sides of the plurality of power storage elements 100 in the X-axis direction at positions sandwiching the insulator 500 with the power storage elements 100 . Each of the two side members 400 is attached to the X-axis direction end portions of the two end members 300 at both Y-axis direction end portions. As a result, the two side members 400 sandwich and constrain the plurality of power storage elements 100 and the plurality of spacers 200 from both sides in the X-axis direction and both sides in the Y-axis direction.

In this way, the side member 400 is arranged on the X-axis plus direction side or the X-axis minus direction side (the side crossing the first direction; hereinafter also referred to as the second direction side) of the plurality of power storage elements 100 . . Here, the second direction is the direction from the storage element 100 toward the side member 400 . Alternatively, the second direction can also be said to be the direction in which the short side surface portion (short side surface portion 111b described later) of the storage element 100 on the side member 400 side faces.

Specifically, the side member 400 has a side member body portion 410 and a pair of side member extension portions 420 . The side member body portion 410 is arranged on the second direction side (the X-axis plus direction side or the X-axis minus direction side) of the power storage element 100 and is arranged to extend in the first direction (Y-axis direction). It is a flat part. The side member extending portion 420 extends from the end of the side member body portion 410 in the first direction (Y-axis plus direction or Y-axis minus direction) in a direction opposite to the second direction (X-axis minus direction or X-axis plus direction). , and is a flat plate-like portion arranged on the first direction side of the inserted member 600 . In the present embodiment, the side member 400 is formed by bending the side member extension portion 420 in the direction opposite to the second direction with respect to the side member body portion 410 extending in the first direction.

The side member 400 is fixed to the end member 300 at each side member extension portion 420 by two fixing members (not shown) arranged in the Z-axis direction. In this embodiment, the fixing member is a bolt that passes through the through hole 421 of the side member extending portion 420 and is joined to the end member 300 . The attachment of the side member 400 to the end member 300 is not limited to fixing with bolts, and may be joined by welding, adhesion, or the like. Further, like the end member 300, the side member 400 is a conductive member formed of a metal (conductive) member such as steel or stainless steel from the viewpoint of strength. or may be insulated.

The insulators 500 are long flat plate-shaped insulating members arranged on both sides of the plurality of power storage elements 100 in the X-axis direction and extending in the Y-axis direction. That is, the insulator 500 is arranged between the plurality of power storage elements 100 and the plurality of spacers 200 and the side member 400 so as to straddle the plurality of power storage elements 100 and the plurality of spacers 200 . and insulate. The insulator 500 is made of an insulating material such as PC, PP, PE, PPS, PET, and ABS resin.

Inserted member 600 is a cylindrical member into which fixing member 700 (see FIG. 4 and the like) that fixes power storage device 10 to an external member is inserted. Specifically, the inserted member 600 is a cylindrical member (collar) formed with a cylindrical through-hole 610 into which the fixing member 700 is inserted. Here, the external member is, for example, a vehicle body on which power storage device 10 is mounted, a cooling device that cools (for example, water-cooling) power storage device 10, an exterior body of equipment on which power storage device 10 is mounted, and the like. Moreover, the fixing member 700 is a bolt that passes through the through hole 610 of the inserted member 600 and is joined (screwed) to the external member. Note that the fixing member 700 is not limited to bolts, and may have a configuration that can be attached to the external member by caulking, welding, or adhesion, for example. In addition, the inserted member 600 is formed of a metal (conductive) member such as steel or stainless steel from the viewpoint of strength or the like, but may be formed of a high-strength insulating member, for example. .

Further, the inserted member 600 is arranged between the end member 300 and the side member 400 so as to be sandwiched between the end member 300 and the side member 400 . Furthermore, the inserted member 600 is fixed to the side member 400 . Specifically, the inserted member 600 is fixed to the side member extending portion 420 . A detailed description of the structure in which the inserted member 600 is fixed to the side member extending portion 420 will be given later.

[2 Detailed Description of Electricity Storage Element 100]
Next, the configuration of the storage element 100 will be described in detail. FIG. 2 is a perspective view showing the structure of the storage element 100 according to this embodiment.

As shown in FIG. 2 , the storage element 100 includes a container 110 , two electrode terminals 120 (a positive electrode terminal and a negative electrode terminal), two gaskets 121 and an insulating sheet 130 . Further, an electrode body, a current collector (a positive electrode current collector and a negative electrode current collector), an electrolytic solution (non-aqueous electrolyte), and the like are accommodated inside the container 110, but illustration of these is omitted. . There is no particular limitation on the type of the electrolytic solution as long as it does not impair the performance of the storage element 100, and various types can be selected. Gaskets are also arranged between the container 110 (cover 112 to be described later) and the current collector, and spacers are arranged on the sides of the current collector, etc., but illustration of these is omitted.

The container 110 is a rectangular parallelepiped (square) container having a container body 111 with an opening and a lid 112 closing the opening of the container body 111 . The container main body 111 is a rectangular cylindrical member that constitutes the main body of the container 110 and has a bottom. That is, the container body 111 has two rectangular long side portions 111a on both sides in the Y-axis direction, two rectangular short side portions 111b on both sides in the X-axis direction, and a negative Z-axis direction. It has a rectangular bottom portion 111c on the direction side. The lid 112 is a rectangular plate-like member that constitutes the lid of the container 110 , and is arranged on the Z-axis plus direction side of the container body 111 . The lid 112 is also provided with a gas discharge valve 113 that releases the pressure inside the container 110 when the pressure rises, and an injection part 114 for injecting an electrolytic solution into the inside of the container 110. ing.

With such a configuration, the container 110 accommodates the electrode body and the like inside the container main body 111, and then the container main body 111 and the lid 112 are joined by welding or the like to form the joint portion 115, whereby the inner is hermetically sealed. The material of the container 110 (the container body 111 and the lid 112) is not particularly limited, but is preferably a weldable (bondable) metal such as stainless steel, aluminum, aluminum alloy, iron, or plated steel plate.

The electrode terminals 120 are terminals (a positive terminal and a negative terminal) of the power storage element 100, and are electrically connected to the positive plate and the negative plate of the electrode assembly via current collectors. In other words, the electrode terminal 120 is made of metal for leading electricity stored in the electrode body to the external space of the storage element 100 and for introducing electricity into the internal space of the storage element 100 to store the electricity in the electrode body. It is a member made of The electrode terminal 120 is made of aluminum, an aluminum alloy, copper, a copper alloy, or the like.

The electrode assembly is a power storage element (power generation element) formed by laminating a positive electrode plate, a negative electrode plate, and a separator. Here, the positive electrode plate included in the electrode assembly is formed by forming a positive electrode active material layer on a positive electrode base material layer, which is a long belt-shaped collector foil made of a metal such as aluminum or an aluminum alloy. Further, the negative electrode plate is formed by forming a negative electrode active material layer on a negative electrode base material layer, which is a long belt-shaped collector foil made of a metal such as copper or a copper alloy. As the positive electrode active material used for the positive electrode active material layer and the negative electrode active material used for the negative electrode active material layer, known materials can be appropriately used as long as they can intercalate and deintercalate lithium ions.

The current collector is a member (a positive electrode current collector and a negative electrode current collector) having conductivity and rigidity, which is electrically connected to the electrode terminal 120 and the electrode body. The positive electrode current collector is made of aluminum or an aluminum alloy like the positive electrode substrate layer of the positive electrode plate, and the negative electrode current collector is made of copper or a copper alloy like the negative electrode substrate layer of the negative electrode plate. It is

The insulating sheet 130 is an insulating sheet-like member arranged on the outer surface of the container 110 to cover the outer surface of the container 110 . Specifically, the insulating sheet 130 is a single insulating sheet arranged so as to cover the entire surface of the bottom portion 111c of the container 110 and almost the entire surfaces of the long side portion 111a and the short side portion 111b. The material of the insulating sheet 130 is not particularly limited as long as it can ensure the insulation required for the storage element 100. Examples include insulating resins such as PC, PP, PE, PPS, PET, and ABS resin. can do.

[3 Detailed Description of End Member 300]
Next, the configuration of the end member 300 will be described in detail. FIG. 3 is a perspective view showing the configuration of the end member 300 according to this embodiment. Specifically, (a) of FIG. 3 is an enlarged perspective view showing the end member 300 on the Y-axis negative direction side shown in FIG. 1, and (b) of FIG. ) is a perspective view showing the configuration of the end member 300 viewed from the Y-axis plus direction side.

4 to 6 are cross-sectional views showing the positional relationship among the storage element 100, the end member 300, the side member 400 and the inserted member 600 according to the present embodiment. Specifically, FIGS. 4 to 6 show the case where the portion of the power storage device 10 shown in FIG. 2 is a cross-sectional view showing the configuration in FIG. FIG. 7 is a cross-sectional view showing the positional relationship among power storage element 100, end member 300, and side member 400 according to the present embodiment. Specifically, FIG. 7 is a cross-sectional view showing a configuration when a portion of power storage device 10 shown in FIG. 1 on the Y-axis negative direction side is cut along line VII-VII.

As shown in these figures, the end member 300 has an end member body portion 310 and a pair of end member extension portions 312 . The end member main body portion 310 is a plate-like portion that constitutes the main body portion of the end member 300, and is arranged on the first direction side (the Y-axis negative direction side in FIGS. 4 to 7) of the end storage element 100a. be. Specifically, the end member body portion 310 is arranged in contact with the spacer 200 on the first direction side of the spacer 200 arranged in contact with the long side portion 111a on the first direction side of the end energy storage element 100a. be done. Note that the end member main body portion 310 is an example of an end plate main body portion.

The end member extending portion 312 is a flat plate-shaped portion that extends in the second direction from the end portion of the end member body portion 310 on the second direction side (X-axis plus direction side or X-axis minus direction side). It is a part. Thereby, the end member extension portion 312 is arranged to extend from the end member main body portion 310 between the fixing member 700 and the end power storage element 100a. Specifically, the end member extending portion 312 is arranged between the inserted member 600 having the fixing member 700 inserted into the through hole 610 and the end power storage element 100a. More specifically, the end member extension 312 is sandwiched between the inserted member 600 and the spacer 200 arranged on the first direction side of the end storage element 100a. In this way, the end member extending portion 312 is formed separately from the inserted member 600 and arranged in contact with the inserted member 600 . Note that the end member extension portion 312 is an example of an end plate extension portion.

Also, the inserted member 600 is fixed to the side member extending portion 420 . Specifically, the portion of the inserted member 600 on the first direction side and the side member extending portion 420 are joined by welding or the like to form the joint portion 800 . Although the inserted member 600 is a cylindrical member, the surface of the inserted member 600 on the first direction side that contacts the side member extending portion 420 is , are formed in a plane. Similarly, the surface of the inserted member 600 on the opposite side of the first direction that contacts the end member extending portion 312 is also formed flat. As a result, the inserted member 600 is sandwiched between the end member extending portion 312 and the side member extending portion 420 while being in surface contact with each other. The joining of the inserted member 600 and the side member extending portion 420 is not limited to welding, and may be joined by adhesion, welding, crimping, fitting, or the like.

Here, the end member body portion 310 has a flat portion 311 , first swelling portions 320 and 330 , and a second swelling portion 340 . The flat portion 311 is a plate-like portion parallel to the XZ plane, and the surface on the side opposite to the first direction (the Y-axis positive direction side in FIG. 4 and the like) abuts the spacer 200 . The first bulging portions 320 and 330 are portions that bulge from the flat portion 311 in the first direction. That is, the first bulging portions 320 and 330 have a shape in which the surface on the first direction side protrudes and the surface on the opposite side to the first direction is recessed. Specifically, the first bulging portion 320 is a bulging portion disposed on the Z-axis positive direction side, the X-axis positive direction side, and the X-axis negative direction side of the end member main body portion 310. The bulging portion 330 is a bulging portion arranged on the Z-axis negative direction side of the end member main body portion 310 .

More specifically, as shown in FIGS. 4 and 7, the first bulging portion 320 intersects the first direction with a first tip wall 321, which is a wall provided at the tip in the first direction. It has a first side wall 322 which is the direction side wall. The first tip wall 321 is a plate-like portion parallel to the XZ plane, and has a screw hole 321a penetrating in the Y-axis direction in the central portion. The screw hole 321 a is a screw hole for fixing the side member extension portion 420 to the first end wall 321 . In other words, a fixing member (bolt) is inserted into the through hole 421 of the side member extension portion 420, and the fixing member is joined (screwed) to the screw hole 321a of the first tip end wall 321, whereby the side member extension A portion 420 is secured to the first distal wall 321 . Thus, the first swelling portion 320 is fixed to the side member 400 .

The first side wall 322 is a curved side wall provided in the X-axis plus direction, the X-axis minus direction, and the Z-axis minus direction of the first bulging portion 320 . The first side wall 322 is parallel to the first direction or slightly inclined with respect to the first direction. That is, the first side wall 322 is arranged parallel to the Y-axis direction or inclined toward the central portion of the first tip end wall 321 toward the Y-axis minus direction.

Similarly, as shown in FIGS. 5 and 7, the first bulging portion 330 includes a first tip wall 331, which is a wall provided at the tip in the first direction, and a wall in the direction intersecting the first direction. It has a first side wall 332 which is a side wall. The first tip wall 331 is a plate-like portion parallel to the XZ plane, and two screw holes 331a are formed on both sides in the X-axis direction so as to penetrate in the Y-axis direction. The threaded hole 331 a is a threaded hole for fixing the side member extension portion 420 to the first tip wall 331 . The detailed configuration is similar to that of the first swelling portion 320 . In this way, the first swelling portion 330 is also fixed to the side member 400 .

It can also be said that the first bulging portions 320 and 330 are projecting portions of the end member main body portion 310 that project in the first direction. That is, the end member main body portion 310 has a projecting portion that projects in the first direction and that is fixed to the side member 400 .

The first side wall 332 is a curved side wall provided in the X-axis plus direction, the X-axis minus direction, and the Z-axis plus direction of the first bulging portion 330 . The first side wall 332 is parallel to the first direction or slightly inclined with respect to the first direction. That is, the first side wall 332 is arranged parallel to the Y-axis direction, or inclined toward the central portion of the first tip end wall 331 toward the Y-axis minus direction.

The second bulging portion 340 is located closer to the central portion of the end storage element 100a than the first bulging portions 320 and 330, and is a portion that bulges from the flat portion 311 in the first direction. Here, the central side of the end storage element 100a is, for example, the direction from the end to the center of the long side surface 111a of the container 110 of the end storage element 100a. That is, the central portion side of the first bulging portion 320 is the Z-axis negative direction side of the first bulging portion 320, and the central portion side of the first bulging portion 330 is the first It is on the Z-axis plus direction side of the bulging portion 330 .

Thus, the second bulging portion 340 is a bulging portion arranged between the first bulging portion 320 and the first bulging portion 330 . That is, the second bulging portion 340 is arranged in the center of the end member main body portion 310 in the Z-axis direction, and has a shape in which the surface on the first direction side protrudes and the surface on the opposite side to the first direction is recessed. and is formed to extend in a direction (second direction) intersecting the first direction.

More specifically, as shown in FIGS. 6 and 7, the second bulging portion 340 has a second tip wall 341, a second side wall 342, and a third side wall 343. As shown in FIGS. The second tip wall 341 is a plate-like wall provided at the tip in the first direction and extending in the X-axis direction. That is, the second tip wall 341 is a bulging wall of the second bulging portion 340 . In addition, the second tip wall 341 has a bulging portion that bulges in the negative Y-axis direction at the central portion in the X-axis direction. In this way, the second bulging portion 340 has a shape that bulges in two stages, thereby suppressing damage such as deformation of the end member 300 .

The second side wall 342 is a side wall in a direction crossing the first direction, specifically, a side wall in the second direction. That is, the second side wall 342 is a curved side wall provided in the X-axis plus direction and the X-axis minus direction of the second bulging portion 340 . The second side wall 342 is arranged so as to incline toward the center portion of the second tip end wall 341 in the X-axis direction as it goes in the negative Y-axis direction. The third side wall 343 is a side wall on the side of the third direction (Z-axis direction) intersecting the first direction and the second direction. That is, the third side wall 343 is a curved side wall provided in the positive Z-axis direction and the negative Z-axis direction of the second bulging portion 340 . The third side wall 343 is arranged parallel to the Y-axis direction, or inclined toward the Z-axis direction central portion of the second end wall 341 toward the Y-axis minus direction.

Here, the second bulging portion 340 is arranged such that the second side wall 342 is closer to the first direction than the first side walls 322 , 332 , which are the side walls of the first bulging portions 320 , 330 in the direction intersecting the first direction. placed at an angle to the That is, the second side wall 342 is inclined with respect to the Y-axis direction so that the angle formed with the Y-axis direction is larger than that of the first side walls 322 and 332 . The second side wall 342 may be arranged more inclined than at least one of the first side wall 322 and the first side wall 332, but in the present embodiment, both the first side wall 322 and the first side wall 332 placed more inclined than

In the present embodiment, since the second side wall 342 and the first side walls 322 and 332 have different angles with the Y-axis direction, the minimum values of the angles with the Y-axis direction are compared. As the angle formed with the Y-axis direction, an acute angle (0° to 90°) is used, and the acute angles are compared. That is, the second side wall 342 is arranged such that the acute angle of the angle formed with the Y-axis direction is larger than the acute angle of the angle formed between the first side walls 322 and 332 and the Y-axis direction. It is formed to be inclined with respect to the Y-axis direction.

Also, the second side wall 342 is arranged to be more inclined with respect to the first direction than the third side wall 343 . That is, in the second bulging portion 340 , the second side wall 342 is inclined with respect to the Y-axis direction so that the angle formed with the Y-axis direction is larger than that of the third side wall 343 . The details are the same as when comparing the second side wall 342 and the first side walls 322 and 332 .

Next, a method of manufacturing the end member 300 in the method of manufacturing the power storage device 10 will be described. First, as a bulging portion forming step, bulging portions (first bulging portions 320 and 330, second bulging portions 320 and 330, second bulging portions, 340). Specifically, in the bulge portion forming step, the bulge portion is formed on the metal member by pressing the heated metal member with a mold after the heating step of heating the metal member. A forming press step is performed.

That is, in the heating step, the metal member is heated from the ferrite state to the austenite region. In the pressing step, the first bulging portions 320 and 330 bulging in the first direction and the first bulging portions 320 and 330 arranged closer to the central portion of the end storage element 100a than the first bulging portions 320 and 330 are arranged in the first direction. A second bulging portion 340 that bulges toward is formed. Specifically, in the pressing step, the second side wall 342, which is the side wall of the second bulging portion 340 in the direction intersecting the first direction, moves in the direction intersecting the first direction of the first bulging portions 320 and 330. The first side walls 322 and 332, which are the side walls, are inclined with respect to the first direction. In the pressing step, the second bulging portion 340 formed by extending in the second direction intersecting the first direction is formed so that the second side wall 342, which is the side wall on the second direction side, It is formed so as to be more inclined with respect to the first direction than the third side wall 343, which is the side wall on the side of the third direction that intersects the two directions. Then, by rapidly cooling the metal member from the austenite state, the metal member changes to the martensite state. As a result, the end member 300 having a complicated shape and high rigidity can be formed.

As described above, the end member 300 is formed of a metal member having a martensite structure, thereby realizing the end member 300 having a complicated shape and high rigidity.

3 to 7, the portion of power storage device 10 in the negative direction of the Y axis in FIG. 1 has been illustrated and explained. It has a similar configuration.

[4 Explanation of effects]
As described above, according to power storage device 10 according to the present embodiment, end member 300 has first bulging portions 320 and 330 and a central portion of end power storage element 100 a relative to first bulging portions 320 and 330 . It has a second bulging portion 340 on the part side. When the power storage element 100 tries to swell, force is applied to the end member 300, and the end member 300 may be deformed or otherwise damaged. A second swelling portion 340 is formed. As a result, even if a force is applied to the end member 300, the force can be suppressed by the first bulging portions 320, 330 and the second bulging portion 340, so that the end member 300 is not deformed or otherwise damaged. can be suppressed.

Also, the second bulging portion 340 is arranged so that the second side wall 342 is inclined more than the first side walls 322 , 332 of the first bulging portions 320 , 330 . Here, since the end storage element 100a swells more easily in the central portion, in the end member 300, the central portion of the end storage element 100a receives a larger force from the end storage element 100a. On the other hand, if the side walls of the bulging portion are inclined with respect to the direction of the bulging, deformation when force is applied to the bulging portion can be suppressed. In other words, the sidewalls (first sidewalls 322 and 332) forming an angle with the flat portion 311 that is nearly right angle apply a larger force (moment) to the boundary portions (corners) between the flat portion 311 and the sidewalls, resulting in expansion. The protrusions (first protrusions 320 and 330) are easily deformed. Therefore, by arranging the second side wall 342 of the second bulging portion 340 on the central side to be more inclined than the first side walls 322, 332 of the first bulging portions 320, 330, the end power storage element 100a It is possible to suppress damage such as deformation of the second bulging portion 340 which receives a large force from. As a result, damage such as deformation of the end member 300 can be suppressed.

In addition, in the end member 300 , the second side wall 342 of the second bulging portion 340 is the side wall of the second bulging portion 340 on the extending direction side. In this way, when the second bulging portion 340 is formed to extend, when a force is received from the end storage element 100a, a large force is exerted on the side wall of the second bulging portion 340 in the extending direction. It takes. Therefore, the side wall of the second bulging portion 340 on the extending direction side is inclined as the second side wall 342 . As a result, damage such as deformation of the second swelling portion 340 can be suppressed, so that damage to the end member 300 can be suppressed.

In addition, in the second bulging portion 340 of the end member 300, the second side wall 342 is disposed more inclined than the third side wall 343 in the direction intersecting the extending direction of the second bulging portion 340. . Here, in the second bulging portion 340, the third side wall 343 extends in the extension direction of the second bulging portion 340 and is longer than the second side wall 342, so the third side wall 343 is inclined. As a result, the area of the surface of the end member 300 facing the end storage element 100a is reduced. Therefore, by making the third side wall 343 not as inclined as the second side wall 342, the area of the surface of the end member 300 facing the end storage element 100a can be secured. As a result, the force from the end storage element 100a can be received over a wider surface, so damage to the end member 300 can be suppressed.

Moreover, since a large force is applied to the second side wall 342 on the extending direction side in the second bulging portion 340 , the third side wall 343 does not need to be inclined as much as the second side wall 342 . Therefore, when it is difficult to incline the side wall when forming the bulging portion in the end member 300, as in hot press forming, the third side wall 343 is not inclined as much as the second side wall 342. Machining of the end member 300 can be facilitated. Thus, in the end member 300, it is possible to suppress damage while facilitating processing.

Also, the first bulging portions 320 and 330 of the end member 300 are fixed to the side member 400 . Here, since the first sidewalls 322 and 332 of the first swelling portions 320 and 330 are not inclined as much as the second sidewall 342 of the second swelling portion 340, the end member 300 facing the end storage element 100a is inclined. If the surface area is not changed, the first bulging portions 320 and 330 can have a larger surface area to be fixed to the side member 400 than the second bulging portion 340 . Therefore, by fixing the side member 400 to the first swelling portions 320 and 330, the side member 400 can be attached to the end member 300 without reducing the area of the surface of the end member 300 facing the end storage element 100a. It can be fixed more firmly. As a result, the end member 300 can be reinforced by the side member 400 while receiving the force from the end power storage element 100a over a wider surface, so that damage to the end member 300 can be further suppressed.

Further, according to the method for manufacturing power storage device 10 according to the present embodiment, the end member 300 is formed with the bulging portions such as the first bulging portions 320 and 330 and the second bulging portion 340 by hot press molding. It includes a bulging portion forming step for forming. In the bulging portion forming step, the bulging portion is formed in the metal member by heating the metal member and then pressing the heated metal member with a mold. In this way, when the power storage element 100 tries to swell, force is applied to the end member 300, and the end member 300 may be deformed or otherwise damaged. form a part. Here, since hot press forming is superior in formability to cold press forming and the like, hot press forming facilitates formation of a bulging portion having a depth sufficient to suppress damage to the end member 300 . can be formed into Furthermore, in hot press forming, the end member 300 having high strength can be formed by heating and pressing the metal member. Thus, the inventor of the present application found that hot press forming is more suitable than conventional cold press forming or the like in order to form the end member 300 having a complicated shape and high strength. . Therefore, even if force is applied to the end member 300, the end member 300 can be easily formed by hot press forming, so that the end member 300 can be prevented from being damaged. .

More specifically, conventionally, the forming of the end member was usually performed by cold press forming. This is because cold press molding costs less than hot press molding. In addition, since the storage element included in the conventional storage device has a relatively small capacity, the force applied to the end member due to swelling of the storage element or the like is relatively small, and even the end member having a relatively simple shape is less likely to be damaged. be. Therefore, in the electric storage device industry, there has been no concept of forming end members by hot press forming.

However, as the capacity of the storage element increases, the force applied to the end member increases due to the swelling of the storage element. , the inventors of the present application have found that it is necessary to complicate the shape of the end member. Furthermore, the inventors of the present application have found that hot press forming is suitable for forming such shaped end members. In this way, the end member 300 that is less likely to be damaged can be easily formed by hot press forming, so that damage to the end member 300 can be suppressed.

In addition, in the method for manufacturing an electric storage device, the first bulging portions 320 and 330 and the second bulging portion 340 closer to the central portion of the end electric storage element 100a than the first bulging portions 320 and 330 are arranged in the second The second side wall 342 of the bulging portion 340 is formed to be more inclined than the first side walls 322 and 332 of the first bulging portions 320 and 330 . Further, the second bulging portion 340 is formed such that the second side wall 342 on the extending direction side is inclined more than the third side wall 343 on the side crossing the extending direction. In this manner, the second side wall 342 of the second bulging portion 340 is formed to be more inclined than the first side walls 322 and 332 of the first bulging portions 320 and 330, thereby receiving from the end storage element 100a. Damage such as deformation of the second swelling portion 340 with a large force can be suppressed. Alternatively, by forming the second side wall 342 on the extending direction side of the second bulging portion 340 to be more inclined than the third side wall 343, the area of the surface of the end member 300 facing the end storage element 100a is ensured, and damage such as deformation of the second swelling portion 340 can be suppressed while receiving the force from the end storage element 100a over a wider surface. As a result, damage to the end member 300 can be suppressed. In particular, hot press-forming is superior in formability to cold press-forming and the like. It is easy to form the second side wall 342 to be more inclined than the third side wall 343 .

[5 Description of modified example]
Although power storage device 10 according to the present embodiment has been described above, the present invention is not limited to the above embodiment. It should be considered that the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is indicated by the scope of claims, and is intended to include all modifications within the meaning and scope of equivalence to the scope of claims.

For example, in the above embodiment, both the portion on the positive side of the Y-axis and the portion on the negative side of the Y-axis of power storage device 10 in FIG. 1 have the above configuration. However, at least one of the portion on the positive side of the Y-axis and the portion on the negative side of the Y-axis of power storage device 10 in FIG. 1 may have the above configuration.

Moreover, in the above embodiment, the end member 300 is a plate-shaped end plate. However, the end member 300 may be a block-shaped member, a rod-shaped member, or the like.

Moreover, in the above-described embodiment, the side member 400 is a plate-like side plate. However, the side member 400 may be a block-shaped member, a rod-shaped member (restriction bar), or the like.

In the above embodiment, the end member 300 has the first sidewalls 322 and 332 of the first bulging portions 320 and 330 and the second sidewall 342 and third sidewall 343 of the second bulging portion 340. , and the second side wall 342 is arranged more inclined than the other side walls. However, the end member 300 may be arranged so that the second side wall 342 is inclined more than at least one of the other side walls. Alternatively, the third side wall 343 instead of the second side wall 342 may be arranged more inclined than the other side walls.

Further, in the above-described embodiment, the end member 300 is formed with the bulging portion by hot press molding. However, the end member 300 may be formed with a bulging portion by a method other than hot press forming, such as press forming without heating, cutting, casting, or the like.

In the above embodiment, fixing member 700 is inserted into inserted member 600 to fix power storage device 10 to an external member. However, the fixing member 700 may be fixed to an external member without the inserted member 600 being provided. Alternatively, power storage device 10 may be configured not to be fixed by fixing member 700 .

Further, in the above-described embodiment, the inserted member 600 is fixed to the side member extending portion 420 . However, the inserted member 600 may be fixed to the side member body portion 410 or may not be fixed to the side member 400 . Also, the inserted member 600 may be fixed to the end member 300 (the end member extending portion 312 or another location).

Also, in the above embodiment, the end member 300 is fixed to the side member 400 at the first swelling portions 320 and 330 . However, the end member 300 may be fixed to the side member 400 at a portion other than the first swelling portions 320 and 330, or may not be directly fixed to the side member 400. FIG.

In addition, in the above embodiment, the first direction, the second direction and the third direction are directions orthogonal to each other. not.

Moreover, the form constructed by arbitrarily combining each component provided in the above embodiment and its modification is also included in the scope of the present invention.

In addition, the present invention can be realized not only as the power storage device 10 and the method for manufacturing the power storage device 10, but also as the end member 300 included in the power storage device 10 or the method for manufacturing the end member 300. can be done.

INDUSTRIAL APPLICABILITY The present invention can be applied to a power storage device having a power storage element such as a lithium ion secondary battery.

10 power storage device 100 power storage element 100a end power storage element 300 end member 310 end member body portion 312 end member extension portion 320, 330 first swelling portion 322, 332 first side wall 340 second swelling portion 342 second side wall 343 Third side wall 400 Side member 410 Side member body portion 420 Side member extension portion 600 Inserted member 700 Fixed member 800 Joining portion

Claims (6)

An electric storage device comprising one or more electric storage elements, and an end member arranged outside in the first direction of an end electric storage element positioned at an outermost end of the one or more electric storage elements in the first direction. a device,
The end member is
a first bulging portion that bulges in the first direction;
a second bulging portion arranged closer to the central portion of the end storage element than the first bulging portion and bulging in the first direction;
The second bulging portion is a side wall arranged at an end portion in a direction intersecting the first direction, and the second side wall is located at an end portion in the direction intersecting the first direction of the first bulging portion. The power storage device is arranged to be inclined with respect to the first direction with respect to the first side wall, which is the arranged side wall. The second bulging portion is formed extending in a second direction that intersects with the first direction,
The power storage device according to claim 1, wherein the second side wall is a side wall arranged at an end portion of the second bulging portion in the second direction. the second bulging portion has a third sidewall that is a sidewall arranged at an end portion in a third direction that intersects the first direction and the second direction;
The power storage device according to claim 2, wherein the second side wall is arranged more inclined with respect to the first direction than the third side wall. further comprising a side member disposed outside the one or more storage elements in a direction crossing the first direction;
The power storage device according to any one of claims 1 to 3, wherein the first swelling portion is fixed to the side member. An electric storage device comprising one or more electric storage elements, and an end member arranged outside in the first direction of an end electric storage element positioned at an outermost end of the one or more electric storage elements in the first direction. a device,
The end member is formed to extend in a second direction that intersects with the first direction, and has a bulging portion that bulges in the first direction,
The bulging portion includes a second side wall that is a side wall arranged at the end in the second direction, and a side wall that is arranged at the end in a third direction intersecting the first direction and the second direction. a third sidewall;
The power storage device, wherein the second side wall is arranged to be more inclined with respect to the first direction than the third side wall. An electric storage device comprising one or more electric storage elements, and an end member arranged outside in the first direction of an end electric storage element positioned at an outermost end of the one or more electric storage elements in the first direction. A method of manufacturing a device, comprising:
a bulging portion forming step of forming a bulging portion that bulges in the first direction in the end member by hot press forming;
The bulging portion forming step includes:
a heating step of heating the metal member;
After the heating step, a pressing step of forming the bulging portion in the metal member by pressing the heated metal member with a mold ,
In the pressing step,
a first bulging portion that bulges in the first direction; and a second bulging portion that is arranged closer to the central portion of the end storage element than the first bulging portion and bulges in the first direction. A second side wall, which is a side wall disposed at an end of the second bulging portion in a direction crossing the first direction, is a direction crossing the first direction of the first bulging portion or
A second side wall, which is a side wall arranged at an end portion in the second direction of the bulging portion formed to extend in a second direction intersecting the first direction, extends in the first direction and the second direction. Formed so as to be more inclined with respect to the first direction than the third side wall, which is the side wall arranged at the end in the third direction that intersects the two directions.
A method for manufacturing a power storage device.

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