JP7713166B2 - Power storage device - Google Patents

Description

The present invention relates to an energy storage device that includes a plurality of energy storage elements arranged in a predetermined direction, a frame that sandwiches the plurality of energy storage elements in a direction perpendicular to the arrangement direction of the energy storage elements, and adjacent members that are disposed between the energy storage elements and fixed to the frame.

Conventionally, a battery system is known that includes a plurality of storage elements arranged in a first direction and a connecting bar (extension member) arranged along the plurality of storage elements (see, for example, Patent Document 1). Specifically, as shown in FIG. 7, this battery system includes a plurality of stacked battery cells 102, a pair of end plates 140 arranged on both ends of the plurality of battery cells 102, and a connecting bar 143 arranged on both sides of the plurality of battery cells 102. The connecting bar 143 is strip-shaped, and both ends of the connecting bar 143 in a predetermined direction are bent inward to provide bent pieces that are fixed to the end plates 140. This fixes the plurality of battery cells 102 in a stacked state.

However, in recent years, as the energy of energy storage devices has increased, the number of storage elements arranged in the energy storage device has increased, and the dimensions of the storage elements in the stacking direction in the energy storage device have tended to become larger. For this reason, there was a need to further improve the rigidity of the energy storage device.

JP 2009-170258 A

Therefore, the objective of this embodiment is to provide an energy storage device with improved rigidity.

The power storage device of this embodiment is
A plurality of storage elements arranged in a first direction;
A pair of extension members each extending in the first direction and sandwiching the plurality of energy storage elements from both sides in a second direction perpendicular to the first direction;
an adjacent member disposed between adjacent ones of the plurality of energy storage elements and fixed to the pair of extension members;
the adjacent member includes a main body member extending between the adjacent energy storage elements, and a connecting member extending from one of the pair of extension members to the other of the pair of extension members, penetrating the main body member, and connecting the pair of extension members to each other;
The connecting member has a shape that is integral with the body member.

With this configuration, the adjacent members, i.e., the connecting member extending from one extension member to the other extension member, and the main body member integrated with this connecting member connect the pair of extension members together, thereby improving the rigidity of the energy storage device.

In the electricity storage device,
The abutment member has a nut,
The connecting member extends in the second direction, so that at least one end of the connecting member penetrates the extending member and protrudes outside the extending member,
At least one end has male threads that engage with a nut;
In at least a portion of the connecting member penetrating the body member in the second direction, a periphery of a cross section perpendicular to the second direction may be non-circular.

With this configuration, at least a portion of the cross section of the connecting member that penetrates the main body member has a non-circular shape, which makes it possible to restrict co-rotation of the connecting member when fitting the nut onto the thread of the connecting member.

In the electricity storage device,
The portion of the connection member penetrating the body member may have a portion in the second direction that has a different cross-sectional area or cross-sectional shape from other portions.

With this configuration, the difference in cross-sectional area or cross-sectional shape of the connecting member can prevent the connecting member from shifting in the second direction relative to the main body member.

The energy storage device of this embodiment can provide an energy storage device with improved rigidity.

FIG. 1 is a perspective view of an electricity storage device according to an embodiment of the present invention. FIG. 2 is a perspective view of an energy storage element in the energy storage device according to the embodiment. FIG. 3 is an exploded perspective view of the electricity storage device according to the embodiment. FIG. 4 is a perspective view of a connecting member of a second adjacent member of the power storage device according to the embodiment. FIG. 5 is a cross-sectional view of a second adjacent member of the power storage device according to the embodiment. FIG. 6 is a cross-sectional view of a second adjacent member of the power storage device according to the embodiment. FIG. 7 is a perspective view for explaining a conventional electricity storage device.

One embodiment of the present invention will be described below with reference to Figures 1 to 6. Note that the names of the components in this embodiment are those used in this embodiment and may differ from the names of the components in the background art.

As shown in FIG. 1, the energy storage device includes a plurality of energy storage elements 1 arranged in a first direction, a pair of extension members 31 each extending in the first direction and sandwiching the plurality of energy storage elements 1 from both sides in a second direction perpendicular to the first direction, and an adjacent member 2 adjacent to the energy storage elements 10 in the first direction.

The energy storage device further includes a holding member 3 that holds the energy storage element 1 and the adjacent member 2 together, and the extension member 31 is a part of the holding member 3. The holding member 3 is made of a conductive material. The energy storage device also includes an insulator 4 that is disposed between the energy storage element 1 and the holding member 3.

For the sake of convenience, in the following description, each direction is described using an orthogonal coordinate system including the X-axis, Y-axis, and Z-axis directions. The direction in which the energy storage elements 1 are aligned (first direction) is referred to as the X-axis direction. Furthermore, one of the two axial directions perpendicular to the direction in which the energy storage elements 1 are aligned (X-axis direction) (second direction) is referred to as the Y-axis direction, and the remaining direction (third direction) is referred to as the Z-axis direction. Accordingly, each drawing additionally illustrates three orthogonal axes (coordinate axes) corresponding to the X-axis, Y-axis, and Z-axis directions.

As shown in FIG. 2, the energy storage element 1 includes an electrode assembly including a positive electrode and a negative electrode, a case 10 that houses the electrode assembly, and a pair of external terminals 11 arranged on the outer surface of the case 10. The energy storage element 1 has a rectangular shape.

The case 10 has a case body 100 with an opening, and a cover plate 101 that closes the opening of the case body 100, and has a pair of external terminals 11 arranged on its outer surface.

The case body 100 includes a blocking portion 100a and a cylindrical body portion 100b that is connected to the periphery of the blocking portion 100a so as to surround the blocking portion 100a. In this embodiment, the body portion 100b is in the shape of a flattened rectangular tube.

The body 100b has a pair of first walls 100c that face each other with a gap between them, and a pair of second walls 100d that face each other with the pair of first walls 100c in between.

The first wall 100c and the second wall 100d are each formed in a rectangular shape. The body 100b is formed in a square tube shape. One end of the body 100b is closed by a closing portion 100a. In contrast, the other end of the body 100b is open and closed by a cover plate 101.

Each of the multiple energy storage elements 1 is aligned in the X-axis direction (see FIG. 1). In this embodiment, each of the multiple energy storage elements 1 is aligned with the first wall 100c of the case 10 facing the X-axis direction. The energy storage device includes a bus bar that electrically connects the external terminals 11 of two adjacent energy storage elements 1.

The adjacent members 2 are insulating and are arranged between the energy storage elements 1 arranged in the X-axis direction, or between the energy storage element 1 and a member arranged in the X-axis direction relative to the energy storage element 1 (in this embodiment, a part of the holding member 3). In this embodiment, the adjacent members 2 are made of insulating resin.

The energy storage device has a plurality of adjacent members 2. In this embodiment, the plurality of energy storage elements 1 and the plurality of adjacent members 2 are arranged alternately in a first direction, and a flow path through which a temperature-adjusting fluid can flow is formed between adjacent energy storage elements 1 and adjacent members 2.

The adjacent members 2 include a plurality of types of adjacent members, and the adjacent members 2 in this embodiment include a first adjacent member 21 arranged between the energy storage elements 1, a second adjacent member 22 arranged between the energy storage elements 1 and fixed to a pair of extension members 31, and a third adjacent member 23 adjacent to the energy storage element 1 at the outer side of the energy storage element 1 at the end in the X-axis direction. That is, the energy storage device includes the first adjacent member 21, the second adjacent member 22, and the third adjacent member 23 as the adjacent members 2. The energy storage device in this embodiment includes a plurality of first adjacent members 21, one second adjacent member 22, and two (a pair) third adjacent members 23. Each of the plurality of first adjacent members 21 is arranged between each of the energy storage elements 1 except between the energy storage elements 1 between which the second adjacent members 22 are arranged.

The second adjacent member 22 is disposed between adjacent energy storage elements 1 among the multiple energy storage elements 1, and is fixed to a pair of extension members 31. As shown in FIG. 3, the second adjacent member 22 includes a main body member 5 extending between adjacent energy storage elements 1, and a connection member 6 connecting the pair of extension members 31. The second adjacent member 22 further includes a fastening member for fastening (engaging) the second adjacent member 22 to the pair of extension members 31, and the fastening member in this embodiment is, for example, a nut 7. The second adjacent member 22 in this embodiment is disposed in the center of the energy storage device in the X-axis direction.

In this embodiment, the second adjacent member 22 has two connection members 6. The second adjacent member 22 also has four fastening members (in this embodiment, nuts 7).

The main body member 5 is made of a resin such as polypropylene. The connecting member 6 is made of metal. The second adjacent member 22 is insert molded. For example, the connecting member 6 is incorporated into a mold, and then resin is filled in, so that the main body member 5 is formed in a state where it is integrated with the connecting member 6.

The main body member 5 is a member that faces the first wall 100c of the case 10 of the energy storage element 1 with a portion of the wall abutting against it.

Specifically, the main body member 5 has a rectangular shape with a size corresponding to the adjacent energy storage element 1 when viewed from the X-axis direction, for example, a rectangular plate shape.

More specifically, the main body member 5 has two opposing surfaces 52 that extend in a direction perpendicular to the X-axis direction at each of one end and the other end in the X-axis direction and that face the adjacent energy storage element 1 (first wall 100c of case 10), and a plurality of protrusions 53 that protrude from each opposing surface 52. As a result, the main body member 5 cooperates with the adjacent energy storage element 1 to form a flow path through which a temperature-regulating fluid can flow between the main body member 5 and the adjacent energy storage element 1.

The ridges 53 are elongated in the Y-axis direction. The multiple ridges 53 are arranged at equal intervals in the Z-axis direction.

The main body member 5 also has an arrangement region 51 in which the connection member 6 is arranged. In this embodiment, the main body member 5 has multiple arrangement regions 51.

The multiple placement areas 51 are arranged at intervals in the Z-axis direction on the end surface 50 of the main body member 5 in the Y-axis direction. In this embodiment, two placement areas 51 are arranged at intervals in the Z-axis direction on the main body member 5. Each placement area 51 is a columnar space. Furthermore, the placement area 51 extends along the Y-axis direction. In this embodiment, each placement area 51 extends in the Y-axis direction between each end surface 50 of the main body member 5 in the Y-axis direction.

For example, as shown in FIG. 5, each placement region 51 extends in the Y-axis direction and has multiple regions with different cross-sectional areas or shapes. More specifically, each placement region 51 has a first region 511 that is a cylindrical space extending in the Y-axis direction, a second region 512 that is a space extending in the Y-axis direction and has a non-circular cross-sectional shape, and a third region 513 that is a cylindrical space extending in the Y-axis direction and has a smaller cross-sectional area than the first region.

The connecting member 6 is a member that connects the pair of extension members 31 together by being fixed to the pair of extension members 31 by fastening, welding, etc. (see FIG. 3). The connecting member 6 extends from one extension member 31A of the pair of extension members 31 to the other extension member 31B of the pair of extension members 31 and penetrates the main body member 5. Furthermore, the connecting member 6 has a shape that is integrated with the main body member 5. The rigidity of the connecting member 6 is higher than the rigidity of the main body member 5.

The two connection members 6 are arranged, for example, at both ends of the main body member 5 in the Z-axis direction. In this embodiment, each connection member 6 is arranged in an arrangement region 51 provided on the main body member 5.

The connection member 6 is surrounded by the resin of the main body member 5 so that the arrangement area 51 of the main body member 5 has a shape corresponding to the connection member 6 (see FIG. 5). In other words, the connection member 6 is arranged without any gaps in the arrangement area 51 of the main body member 5.

For example, the connection member 6 is a columnar member. The connection member 6 extends along the Y-axis direction. In this embodiment, the connection member 6 is substantially cylindrical and extends in the Y-axis direction. Specifically, the connection member 6 is a metal rod whose dimension in the Y-axis direction is at least longer than the dimension in the Y-axis direction of the main body member 5.

In this embodiment, the connecting member 6 extends in the Y-axis direction, so that at least one end 60 of the connecting member 6 protrudes outside the pair of extension members 31 (one extension member 31A or the other extension member 31B) while penetrating the extension member 31 (see FIG. 1). Specifically, the connecting member 6 extends in the Y-axis direction, so that both end portions 60 of the connecting member 6 protrude outside the pair of extension members 31.

In addition, as shown in FIG. 4, at least one end 60 of the connection member 6 has an engaged portion with which a fastening member or the like engages or screws. This engaged portion is, for example, a male thread with which a nut 7 engages. Specifically, both end portions 60 of the connection member 6 have male threads with which a nut 7 engages.

The connecting member 6 further has a main body portion 61 that connects both ends 60. The portion (main body portion 61) of the connecting member 6 that penetrates the main body member 5 has a portion (first portion 62) in a part in the Y-axis direction that has a different cross-sectional area or cross-sectional shape from other portions (second portion 63 and third portion 64). In this embodiment, the first portion 62 has a different cross-sectional shape from the second portion 63 and the third portion 64 (portions of the main body portion 61 other than the first portion 62).

In this embodiment, the connection member 6 has multiple (e.g., three) first portions 62. The first portions 62 are disposed at an intermediate position (e.g., a central position) in the Y-axis direction of the main body portion 61 and at positions on both sides of this intermediate position. Adjacent first portions 62 in the Y-axis direction are arranged at equal intervals. In addition, the cross-sectional outline of the first portions 62 is circular.

In addition, in this embodiment, the periphery (contour of the cross section) of the cross section perpendicular to the Y-axis direction in at least a portion (in this embodiment, the second portion 63) in the Y-axis direction of the portion (main portion 61) of the connecting member 6 penetrating the main body member 5 is non-circular (a shape having projections and recesses) as shown in FIG. 6. The connecting member 6 has a plurality of (e.g., two) second portions 63. The second portions 63 are disposed over substantially the entire main body portion 61 (see FIG. 4). Specifically, the second portions 63 are separated by the first portions 62. Note that the second portions 63 are not formed on both ends 60 of the connecting member 6 (portions protruding from the main body member 5).

The cross-sectional contour of the second portion 63 has at least one protrusion 630 protruding radially outward from the circumference, for example, a plurality of protrusions 630 (see FIG. 6). In this embodiment, the cross-sectional contour of the second portion 63 is the same at any portion in the Y-axis direction.

Specifically, the multiple protrusions 630 are arranged, for example, in the circumferential direction. Furthermore, the protrusions 630 are arranged at equal intervals in the circumferential direction. The cross-sectional shapes of the protrusions 630 are all the same. Furthermore, the protrusions 630 are ridges 630 that extend in the Y-axis direction (see FIG. 4). Furthermore, the circumferential positions of the protrusions 630 are the same on both sides of the first portion 62, which is located midway in the Y-axis direction.

In this embodiment, the connection member 6 has multiple (e.g., two) third portions 64. The third portions 64 are disposed at both ends of the main body portion 61. The third portions 64 are disposed in the Y-axis direction at positions sandwiching the second portion 63 together with the first portion 62. Furthermore, the cross-sectional contour of the third portion 64 is circular.

The nut 7 is a member that fixes the connection member 6 to the extension member 31 (see FIG. 3). The nut 7 is arranged in a position that sandwiches one extension member 31A or the other extension member 31B together with the main body member 5. The nut 7 is, for example, a nut that fixes the end 60 of the connection member 6 to the extension member 31. In this embodiment, the male thread of the end 60 of the connection member 6 that has penetrated the pair of extension members 31 engages (screws) with the nut, thereby fixing the main body member 5 to the holding member 3.

In this embodiment, each extension member 31 is sandwiched between each end 60 of the connection member 6 and the nut 7. Also, in this embodiment, the connection member 6 is configured not to come off from the main body member 5 in the Y-axis direction, so that the pair of extension members 31 are fixed to the second adjacent member 22 by sandwiching the three members, one extension member 31A, the main body member 5, and the other extension member 31B, between each end 60 of the connection member 6 and the nut 7 engaged with each end 60.

Each of the first adjacent members 21 has a first body portion that extends in a direction perpendicular to the X-axis direction between adjacent energy storage elements 1 in the X-axis direction, and at least one first restricting portion that extends in the X-axis direction from the outer periphery of the first body portion (in this embodiment, the four corners of the rectangular plate-shaped first body portion) and restricts the movement of the energy storage element 1 adjacent to the first body portion relative to the first body portion. Each of the first adjacent members 21 also forms at least one flow path between adjacent energy storage elements 1 through which a temperature adjustment fluid can flow. The thickness in the X-axis direction of the first body portion of the first adjacent member 21 is thinner than, for example, the thickness in the X-axis direction of the body member 5 of the second adjacent member 22.

Each of the two third adjacent members 23 has a third main body portion that extends in a direction perpendicular to the X-axis direction between the adjacent energy storage elements 1 in the X-axis direction and the holding member 3 (more specifically, the terminal member 30), and at least one third restricting portion that extends in the X-axis direction from the outer periphery of the third main body portion (in this embodiment, the four corners of the rectangular plate-shaped third main body portion) and restricts the movement of the adjacent energy storage element 1 relative to the third main body portion. In addition, each of the two third adjacent members 23 forms at least one flow path between the adjacent energy storage elements 1 through which a temperature adjustment fluid can flow.

In this embodiment, the retaining member 3 is made of metal. The retaining member 3 includes a pair of end members 30 arranged at positions adjacent to each of the third adjacent members 23, and a pair of extension members 31 connecting the pair of end members 30.

Each of the pair of end members 30 has a first surface facing the third adjacent member 23 and a second surface opposite the first surface. Each of the pair of end members 30 abuts against the third adjacent member 23.

The end member 30 is made of metal. When viewed from the X-axis direction, the end member 30 has a shape corresponding to that of the energy storage element 1.

Each extension member 31 has a connection portion 310, 311 extending between a pair of end members 30. In this embodiment, each of the pair of extension members 31 has a first connection portion 310 extending in the X-axis direction at a position corresponding to one end of the plurality of energy storage elements 1 in the Z-axis direction, a second connection portion 311 extending in the X-axis direction at a position corresponding to the other end of the plurality of energy storage elements 1 in the Z-axis direction, and a plurality of reinforcing portions 312 extending in the Z-axis direction to connect the first connection portion 310 and the second connection portion 311. In this embodiment, the pair of extension members 31 are frame-shaped (frame-shaped), but may be other shapes such as bar-shaped (belt-shaped) or plate-shaped (plate-shaped).

The first connection portion 310 and the second connection portion 311 are arranged at an interval in the Z-axis direction. Each of the first connection portion 310 and the second connection portion 311 has a first end in the longitudinal direction and a second end opposite the first end.

In addition, each of the first connection portion 310 and the second connection portion 311 is bent along the longitudinal direction. In each of the first connection portions 310, one of the portions bordered by the bent portion is positioned at a position corresponding to the cover plate 101 or the blocking portion 100a of the energy storage element 1. In each of the first connection portion 310 and the second connection portion 311, the other of the portions bordered by the bent portion is positioned at a position corresponding to the second wall 100d of the energy storage element 1.

The multiple reinforcing parts 312 are spaced apart in the X-axis direction. In this embodiment, the multiple reinforcing parts 312 include a pair of first reinforcing parts 313 that connect the ends of the first connecting part 310 and the second connecting part 311 that are spaced apart in the Z-axis direction, and multiple (seven in this embodiment) second reinforcing parts 314 that connect the areas excluding the ends of the first connecting part 310 and the second connecting part 311 that are spaced apart in the Z-axis direction.

The first reinforcing portion 313 is connected to the end member 30.

The second reinforcing portion 314 is provided with a through hole 314a through which the connecting member 6 is inserted. In this embodiment, the second reinforcing portion 314, which is disposed at the center position in the X-axis direction of the first connecting portion 310 and the second connecting portion 311, is provided with the through hole 314a. The number of through holes 314a is the same as the number of connecting members 6. More specifically, the second reinforcing portion 314 is provided with a pair of through holes 314a, which are disposed at each end in the Z-axis direction.

The insulator 4 has a shape corresponding to each extension member 31. The insulator 4 is also disposed between each extension member 31 and the multiple energy storage elements 1 to insulate them from each other.

According to the above-described energy storage device, the second adjacent member 22, i.e., the connecting member 6 extending from one extension member 31A to the other extension member 31B, and the main body member 5 integrated with this connecting member 6 connect the pair of extension members 31 together, thereby improving the rigidity of the energy storage device.

In the energy storage device of this embodiment, at least a portion of the section (main body section 61) of the connection member 6 that penetrates the main body member 5 has a non-circular cross section, so that the rotation of the connection member 6 about the extension direction is restricted, and the co-rotation of the connection member 6 can be restricted when the nuts 7 are fitted into the screws provided at both ends 60 of the connection member 6. Specifically, at least a portion of the main body section 61 of the connection member 6 has a non-circular cross section, and the main body member 5 surrounds the connection member 6 (the second section 63, which is a section having a non-circular cross section) without any gaps, so that the co-rotation of the connection member 6 can be restricted. More specifically, the co-rotation of the connection member 6 can be restricted when the connection member 6 is connected to a pair of extension members 31 by fitting the nuts 7 into the screws provided at both ends 60 of the connection member 6.

In addition, in the energy storage device of this embodiment, the difference in cross-sectional area or cross-sectional shape of the connecting member 6 (in this embodiment, the cross-sectional shape of the first portion 62) can regulate the misalignment of the connecting member 6 in the Y-axis direction relative to the pair of extension members 31. Specifically, the main body portion 61 of the connecting member 6 has portions with different cross-sectional areas and cross-sectional shapes, and the main body member 5 surrounds the connecting member 6 (the portions of the connecting member 6 with different cross-sectional areas and cross-sectional shapes) without any gaps, thereby regulating the prevention of the connecting member 6 from coming loose in the Y-axis direction.

The energy storage device according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

For example, the second adjacent member 22 is not limited to the configuration of the above embodiment. The second adjacent member 22 may include one connecting member 6, or may include three or more connecting members 6. Note that the number of fastening members (e.g., nuts 7 that screw into the male threads of the end 60) that engage with the end 60 of the connecting member 6 may be provided in a number that corresponds to the number of engaging portions of the end 60 of the connecting member 6.

The second adjacent member 22 may not have a nut 7. In this case, the connecting member 6 may not have male threads on both ends 60 of the connecting member 6, and the both ends 60 may be fixed by welding to a pair of extension members 31, respectively.

The connecting member 6 may be rod-shaped with a circular cross section. Specifically, the periphery of the cross section of the entire main body portion 61 in the Y-axis direction may be circular. Furthermore, the cross-sectional area and cross-sectional shape of the entire main body portion 61 in the Y-axis direction may be the same.

Furthermore, the connection member 6 may extend from one extension member 31A to the other extension member 31B and penetrate the main body member 5, and may be a rectangular columnar member as a whole, or a columnar member with a curved intermediate portion in the Y-axis direction. The connection member 6 may also be, for example, a band-shaped member extending in the Y-axis direction. The connection member 6 may also be a member with a plate-shaped intermediate portion in the Y-axis direction and columnar ends at both ends in the Y-axis direction.

The connecting members 6 may be configured such that the intermediate portions of the two connecting members 6 in the Y-axis direction are connected at a portion extending in the Z-axis direction.

Furthermore, a male thread may be provided on only one end 60 of the connection member 6. In this case, the end 60 with the male thread may be fixed to the extension member 31 with a nut 7, and the end 60 without the male thread may be fixed to the extension member 31 by welding.

In addition, in the connection member 6, the cross-sectional area of the first portion 62 may be different from that of a portion of the main body portion 61 other than the first portion 62 (e.g., the second portion 63). In other words, when the main body portion 61 is substantially cylindrical, the diameter of the first portion 62 may be different from the diameter of a portion of the main body portion 61 other than the first portion 62 (e.g., the second portion 63).

The second adjacent member 22 may also be disposed at a position other than the middle position in the X-axis direction of the power storage device. Furthermore, the power storage device may include multiple second adjacent members 22.

1...electricity storage element, 2...adjacent member, 3...holding member, 4...insulator, 5...main body member, 6...connecting member, 7...nut, 10...case, 11...external terminal, 21...first adjacent member, 22...second adjacent member, 23...third adjacent member, 30...termination member, 31...extension member, 31A...one extension member, 31B...other extension member, 50...end surface, 51...arrangement area, 52...opposing surface, 53...ridge, 60...end portion, 61...main body portion, 62...first portion, 63...second portion , 64...third part, 100...case body, 100a...blocking part, 100b...body part, 100c...first wall, 100d...second wall, 101...cover plate, 102...battery cell, 140...end plate, 143...connecting bar, 310...first connection part (connection part), 311...second connection part (connection part), 312...reinforcement part, 313...first reinforcement part, 314...second reinforcement part, 314a...through hole, 511...first region, 512...second region, 513...third region, 630...projection part (projection strip)

Claims (2)

A plurality of storage elements arranged in a first direction;
A pair of extension members each extending in the first direction and sandwiching the plurality of energy storage elements from both sides in a second direction perpendicular to the first direction;
an adjacent member disposed between adjacent ones of the plurality of energy storage elements and fixed to the pair of extension members;
the adjacent member includes a main body member extending between the adjacent energy storage elements, a connecting member extending from one of the pair of extension members to the other of the pair of extension members, penetrating the main body member, and connecting the pair of extension members to each other, and a nut ;
the connecting member has a shape integral with the main body member and extends in the second direction, so that at least one end of the connecting member penetrates the extending member and protrudes outside the extending member;
At least one end has a male thread that engages with the nut;
The power storage device , wherein a periphery of a cross section perpendicular to the second direction in at least a part of the second direction of a portion of the connection member that penetrates the body member is non-circular . The power storage device according to claim 1 , wherein the portion of the connection member penetrating the body member has a portion in the second direction that has a different cross-sectional area or cross-sectional shape from other portions.