Power storage device

Abstract

A power storage device according to the present embodiment is characterized by comprising a plurality of power storage elements, a stretchable member adjacent to the plurality of power storage elements in a first direction, and an insulating member disposed between the plurality of power storage elements and the stretchable member, wherein: the stretchable member has a first main body part and a first piece part, the first main body part extending in a second direction crossing the first direction and in a third direction crossing both the first direction and the second direction, the first piece part having a first piece section extending in the first direction from an end section of the first main body part in the second direction, and also extending in the third direction, and the first main body part and the first piece part each being disposed along the plurality of power storage elements; the insulating member has a second main body part and a second piece part, the second main body part extending, between the plurality of power storage elements and the first main body part, along the first main body part, and the second piece part being connected to an end section of the second main body part in the second direction between the plurality of power storage elements and the first piece part, and extending along the first piece part; and the first piece part and the second piece part are engaged with each other.

Description

Power storage device

[0001] The present invention relates to an energy storage device including a plurality of energy storage elements.

[0002] A power supply device in which an insulating material is disposed between a plurality of battery cells and a bind bar has been known (see Patent Document 1). As shown in Fig. 12, this power supply device 500 includes a battery stack 502 formed by stacking a plurality of battery cells 501, a pair of end plates 503 disposed at both ends of the battery stack 502 in the stacking direction, and a bind bar 504 fixed to the end plates 503.

[0003] The battery cells 501 have a plate-like outer shape with a thickness thinner than its width, and are stacked in multiple layers with rectangular main surfaces. Specifically, the battery cells 501 have an outer can that forms their outer shape with a rectangular shape with a thickness thinner than their width.

[0004] 13 , a pair of end plates 503 cover both end faces of a battery stack 502, which is made up of battery cells 501 stacked alternately with separators 505 in between. The pair of end plates 503 are secured by bind bars 504 to hold the battery stack 502 in place. Each end plate 503 is made from a single metal plate.

[0005] The bind bar 504 has a main body plate 506 whose ends are fixed to the end plates 503. As shown in Figure 13, this main body plate is arranged on both sides of the battery stack 502, which has end plates 503 stacked on both ends, and has its ends fixed to the pair of end plates 503.

[0006] Specifically, the main plate 506 is formed in a plate shape that extends in the battery stacking direction of the battery stack 502. More specifically, the main plate 506 has a flat main fastening surface 507 that covers the side surface of the battery stack 502, and first, second, third, and fourth bent pieces 508, 509, 510, and 511 as bent pieces formed by bending the edges of the main fastening surface 507.

[0007] The first bent piece 508 is an upper bent piece bent at the top end. The second bent piece 509 is a lower bent piece bent at the bottom end, and they each partially cover the corners of the underside of the battery stack 502. The third bent piece 510 is an end plate fixing piece partially bent at the front end, and the fourth bent piece 511 is an end plate fixing piece partially bent at the rear end.

[0008] The main body plate 506 is manufactured by bending a metal plate, and is fixed to the end plate 503 by means of end plate fixing pieces and screws.

[0009] In the power supply device 500, an insulating structure can be provided between the metal body plate 506 and the battery stack 502 to prevent short circuits between the metal body plate 506 and the outer casing of the battery cell 501. In the example shown in Figure 13, an insulating material 512 is interposed between the metal body plate 506 and the battery stack 502.

[0010] The insulating material 512 is made of a resin sheet or the like. The shape of the insulating material 512 is substantially the same as that of the main plate, and prevents the side surfaces of the battery stack from coming into contact with the main plate. In the example shown in Figure 13, the insulating material 512 is formed in a sheet shape that covers almost the entire inner surface of the main plate 506.

[0011] In the above power supply device, the second bent piece 509 (lower bent piece) and the portion of the insulating material 512 that corresponds to the second bent piece (corresponding portion) simply overlap, so the corresponding portion of the insulating material 512 may become misaligned (i.e., move) relative to the second bent piece 509 due to vibrations during assembly of the power supply device 500 or during use of the power supply device 500. If the corresponding portion of the insulating material 512 moves relative to the second bent piece 509 in this way, there is a concern that sufficient insulation between the battery stack 502 and the main plate 506 may not be achieved.

[0012] Japanese Patent Application Laid-Open No. 2021-26875

[0013] Therefore, an object of this embodiment is to provide an electricity storage device in which the second arm of the insulating member is less likely to move relative to the first arm of the extension member.

[0014] The energy storage device of this embodiment comprises a plurality of energy storage elements; an extension member adjacent to the plurality of energy storage elements; and an insulating member arranged between the plurality of energy storage elements and the extension member, wherein the extension member has: a first main body portion extending in a direction perpendicular to a first direction, which is the arrangement direction of the plurality of energy storage elements; and a first arm portion extending in the first direction from an end of the first body portion in a second direction perpendicular to the first direction and extending in a third direction perpendicular to both the first direction and the second direction, wherein each of the first main body portion and the first arm portion is arranged along the plurality of energy storage elements, and the insulating member has: a second main body portion extending along the first body portion between the plurality of energy storage elements and the first body portion; and a second arm portion connected to the end of the second body portion in the second direction between the plurality of energy storage elements and the first arm portion and extending along the first arm, wherein the first arm portion and the second arm portion are engaged with each other.

[0015] As described above, according to this embodiment, it is possible to provide an electricity storage device in which the second arm of the insulating member is less likely to move relative to the first arm of the extension member.

[0016] FIG. 1 is a perspective view of the power storage device according to this embodiment. FIG. 2 is an exploded perspective view of the power storage device. FIG. 3 is a cross-sectional view of the power storage device. FIG. 4A is an enlarged view at position IV in FIG. 3. FIG. 4B is an enlarged cross-sectional view of a power storage device according to a comparative example. FIG. 5 is a perspective view of an extension member of the power storage device. FIG. 6 is a side view of the extension member. FIG. 7 is a perspective view of an insulating member of the power storage device, and FIG. 8 is an enlarged view at position VIII in FIG. 7. FIG. 9 is a bottom view of the insulating member. FIG. 10 is a cross-sectional view at position X-X in FIG. 9. FIG. 11 is a cross-sectional view at position XI-XI in FIG. 9. FIG. 12 is a perspective view of a conventional power supply device. FIG. 13 is an exploded view of the power supply device.

[0017] (1) An energy storage device of this embodiment includes: a plurality of energy storage elements; an extension member adjacent to the plurality of energy storage elements; and an insulating member arranged between the plurality of energy storage elements and the extension member, wherein the extension member has: a first main body portion extending in a direction perpendicular to a first direction, which is the arrangement direction of the plurality of energy storage elements; and a first arm portion extending in the first direction from an end of the first body portion in a second direction perpendicular to the first direction and extending in a third direction perpendicular to both the first direction and the second direction, wherein the first main body portion and the first arm portion are each arranged along the plurality of energy storage elements, and the insulating member has: a second main body portion extending along the first main body portion between the plurality of energy storage elements and the first body portion; and a second arm portion connected to the end of the second body portion in the second direction between the plurality of energy storage elements and the first arm portion and extending along the first arm portion, wherein the first arm portion and the second arm portion are engaged with each other.

[0018] By engaging the first piece and the second piece in this manner, movement of the second piece relative to the first piece is suppressed.

[0019] (2) In the storage device described in (1) above, in the storage device of this embodiment, the first arm and the second arm may be engaged in an intermediate region excluding each end of the first arm in the first direction and the third direction.

[0020] According to this configuration, movement of the second arm portion is effectively suppressed in the intermediate region of the first arm portion excluding each end portion in the first direction and the third direction.

[0021] (3) In the energy storage device described in (1) or (2) above, in the energy storage device of this embodiment, the first arm has a first surface facing the plurality of energy storage elements in the second direction and a second surface that is the reverse side of the first surface, and the second arm may be arranged between the plurality of energy storage elements and the first arm so as not to extend beyond the second surface in the direction from the second arm toward the first arm.

[0022] With this configuration, the dimensions of the storage device in the second direction can be reduced by the portion that exceeds the second surface (i.e., miniaturization in the second direction) compared to a configuration in which a portion of the second arm extends beyond the second surface of the first arm.

[0023] (4) In the energy storage device described in (1) or (2) above, in the energy storage device of this embodiment, the first arm may have a arm body having the first surface and the second surface, and an engaging portion that protrudes from the arm body in a direction toward the second arm and engages with the second arm.

[0024] This simple configuration, in which the engaging portion protruding from the main body of the arm portion engages with the second arm portion, makes it easy to realize a configuration in which the first arm portion and the second arm portion engage with each other without any part of the second arm portion extending beyond the second surface of the first arm portion.

[0025] An embodiment of the present invention will be described below with reference to Figures 1 to 11. 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.

[0026] 1 and 2 , the energy storage device 1 of this embodiment includes a plurality of energy storage elements 10, extension members 42 adjacent to the plurality of energy storage elements 10, and an insulating member 7 arranged between the plurality of energy storage elements 10 and the extension members 42. Specifically, the energy storage device 1 includes a plurality of energy storage elements 10 arranged in a predetermined direction, a plurality of adjacent members 2 adjacent to the energy storage elements 10 in the predetermined direction, and a holding member 4 having extension members 42 and holding the plurality of energy storage elements 10 and the plurality of adjacent members 2. The energy storage device 1 includes a first fastening member B that fixes at least one adjacent member 2 to the holding member 4, at least one insulating member 7 that insulates between the plurality of energy storage elements 10 and the holding member 4, and a plurality of bus bars 8 that electrically connect different energy storage elements 10 to each other.

[0027] Each of the plurality of energy storage elements 10 is a primary battery, a secondary battery, a capacitor, or the like. The energy storage element 10 of this embodiment is a chargeable and dischargeable non-aqueous electrolyte secondary battery. More specifically, the energy storage element 10 is a lithium ion secondary battery that utilizes electron transfer that occurs with the transfer of lithium ions.

[0028] Specifically, each energy storage element 10 comprises an electrode body, a case 11 that houses the electrode body together with an electrolyte, an external terminal 14 at least a portion of which is exposed to the outside of the case 11, and a current collector that connects the electrode body and the external terminal 14.

[0029] In the electrode assembly, positive electrodes and negative electrodes are alternately stacked with separators interposed therebetween. Lithium ions move between the positive electrodes and negative electrodes in this electrode assembly, thereby charging and discharging the energy storage element 10.

[0030] The case 11 has a case body 12 having an opening, and a plate-like cover plate 13 that closes the opening of the case body 12. The case body 12 has a rectangular tubular shape with one end in the opening direction closed (i.e., a rectangular tubular shape with a bottom), and the case 11 has a rectangular parallelepiped shape (six-sided shape).

[0031] Specifically, the case body 12 includes a plate-shaped closing portion 121 and a cylindrical body portion (peripheral wall) 122 connected to the periphery of the closing portion 121 .

[0032] The closing portion 121 is a plate-like portion that is located at the lower end of the case body 12 when the case body 12 is placed with the opening facing upward (i.e., it forms the bottom wall of the case body 12 when the opening faces upward). The closing portion 121 has a rectangular plate shape when viewed from the normal direction of the closing portion 121.

[0033] The body 122 has a rectangular cylindrical shape, more specifically, a flattened rectangular cylindrical shape. The body 122 has a pair of long wall portions 123 extending from the long sides of the periphery of the closing portion 121, and a pair of short wall portions 124 extending from the short sides of the periphery of the closing portion 121. The long wall portions 123 and the short wall portions 124 are both plate-shaped (specifically, rectangular plate-shaped). In this body 122, the short wall portions 124 connect corresponding ends of the pair of long wall portions 123 to each other, thereby forming the rectangular cylindrical body 122.

[0034] The cover plate 13 is a plate-shaped member that closes the opening of the case body 12. In this embodiment, the cover plate 13 is rectangular. The case 11 is formed by joining the cover plate 13 to the case body 12 with the peripheral edge of the cover plate 13 overlapping the peripheral edge of the opening of the case body 12.

[0035] The case 11 has a flat rectangular parallelepiped shape, and the energy storage elements 10 are arranged in the predetermined direction with the wide surfaces (long wall portions 123) of the case 11 facing each other.

[0036] The external terminals 14 are portions that are electrically connected to external terminals of other energy storage elements or external devices, etc. The external terminals 14 are formed of a conductive material. For example, the external terminals 14 are formed of a metal material with high weldability, such as an aluminum-based metal material such as aluminum or an aluminum alloy, or a copper-based metal material such as copper or a copper alloy. The energy storage element 10 of this embodiment has two external terminals 14, which are arranged at both longitudinal ends of the cover plate 13.

[0037] In the following description, the direction in which the multiple energy storage elements 10 are lined up (predetermined direction, third direction) is defined as the X-axis of a Cartesian coordinate system, the direction in which the short wall portions 124 of the case 11 face each other is defined as the Y-axis (first direction) of the Cartesian coordinate system, and the direction in which the cover plate 13 and the closing portion 121 face each other is defined as the Z-axis (second direction) of the Cartesian coordinate system. The short wall portions 124 extend in the Y-axis direction and the Z-axis direction. The closing portion 121 extends in the X-axis direction and the Y-axis direction.

[0038] Each of the bus bars 8 is a plate-shaped member having electrical conductivity, such as metal. Each bus bar 8 electrically connects the external terminals 14 of the energy storage elements 10 to each other. In this embodiment, the bus bars 8 connect (connect) the energy storage elements 10 included in the energy storage device 1 in series.

[0039] The adjacent members 2 are insulating and are arranged between the energy storage elements 10 lined up in the X-axis direction, or between the energy storage elements 10 and a member (in this embodiment, a part of the holding member 4) lined up in the X-axis direction relative to the energy storage elements 10. The adjacent members 2 in this embodiment are made of resin. The adjacent members 2 form flow paths between adjacent energy storage elements 10 through which a temperature-regulating fluid (in this embodiment, a gas such as air) can flow. The energy storage device 1 in this embodiment includes a plurality of adjacent members 2, and these plurality of adjacent members 2 include a plurality of types of adjacent members 2A, 2B, and 2C.

[0040] Specifically, the multiple adjacent members 2 include a first adjacent member 2A arranged between two adjacent energy storage elements 10, a second adjacent member 2B arranged between the adjacent energy storage elements 10 and fixed to the holding member 4, and a third adjacent member 2C adjacent to the energy storage element 10 between the holding member 4 and the energy storage element 10 at the farthest end in the X-axis direction. That is, the energy storage device 1 includes the first adjacent member 2A, the second adjacent member 2B, and the third adjacent member 2C as adjacent members 2. The energy storage device 1 of this embodiment includes multiple first adjacent members 2A, one second adjacent member 2B, and two (a pair) third adjacent members 2C. Each of these multiple first adjacent members 2A is arranged between each of the energy storage elements 10 except for the space between the energy storage elements 10 where the second adjacent member 2B is arranged. The second adjacent member 2B is fixed to the holding member 4 (specifically, the extension member 42) by a first fastening member B.

[0041] The holding member 4 surrounds the plurality of energy storage elements 10 and the plurality of adjacent members 2, thereby holding the plurality of energy storage elements 10 and the plurality of adjacent members 2 together. The holding member 4 is made of a conductive material such as a metal.

[0042] Specifically, the holding member 4 has a pair of end members 41 arranged on both sides of the multiple energy storage elements 10 (a stack of energy storage elements 10) in the X-axis direction, extension members 42 extending in the X-axis direction along the multiple energy storage elements 10, and connecting members 43 connecting the end members 41 and the extension members 42. More specifically, the holding member 4 of this embodiment has a pair of extension members 42, which are arranged on both sides of the multiple energy storage elements 10 in the Y-axis direction and connect the pair of end members 41. The holding member 4 of this embodiment has a plurality of connecting members 43.

[0043] Each of the pair of end members 41 is arranged so as to sandwich the third adjacent member 2C between itself and the energy storage element 10 arranged at the end (outermost) in the X-axis direction. Each of the pair of end members 41 has a rectangular plate shape whose size corresponds to that of the energy storage element 10. Specifically, each end member 41 has a rectangular shape that is elongated in the Y-axis direction.

[0044] 5 and 6 , each of the pair of extension members 42 has an extension side portion (first main body portion) 44 that extends in a direction perpendicular to the Y-axis direction, which is the arrangement direction of the multiple energy storage elements 10, and an extension bottom surface portion (first piece portion) 45 that extends in the Y-axis direction from an end of the extension side portion 44 in the Z-axis direction, which is perpendicular to the Y-axis direction, and that extends in the X-axis direction, which is perpendicular to both the Y-axis direction and the Z-axis direction. The extension side portion 44 and the extension bottom surface portion 45 are each arranged along the multiple energy storage elements 10 (see FIG. 2 ).

[0045] In the holding member 4 of this embodiment, the extended bottom surface portion 45 extends from one end in the Z direction of the extended side surface portion 44. Each of the pair of extension members 42 has an extended top surface portion 46 that extends in the Y axis direction from an end of the extended side surface portion 44 in the Z axis direction that is perpendicular to the Y axis direction and that extends in the X axis direction that is perpendicular to both the Y axis direction and the Z axis direction, and a pair of extended end surface portions 47 that extend in the Y axis direction along the termination member 41 from each end of the extended side surface portion 44 in the X axis direction and that extend in the Z axis direction.

[0046] The extended side surface portion 44 faces the short wall portion 124 of each energy storage element 10. The extended side surface portion 44 is in the form of a plate that extends along the short wall portion 124 of each energy storage element 10, and has a plurality of through holes 440 that penetrate in the Y-axis direction to allow the temperature adjustment fluid to flow in or out of each flow path.

[0047] The extended bottom surface portion 45 extends from one end of the extended side surface portion 44 in the Z-axis direction along the closed portion 121 of each energy storage element 10 in the Y-axis direction and also in the X-axis direction. The extended bottom surface portion 45 is a long strip in the X-axis direction, and its dimension (width) in the Y-axis direction is constant at each position except for both ends in the X-axis direction. As shown in FIGS. 3 and 4A , the extended bottom surface portion 45 has a first surface 451 that faces the multiple energy storage elements 10 in the Z-axis direction, and a second surface 452 that is the back surface of the first surface 451. In the extension member 42 of this embodiment, the first surface 451 and the second surface 452 of the extended bottom surface portion 45 are both flat surfaces.

[0048] In the energy storage device 1 of this embodiment, the extended bottom surface portion 45 has a half body 453 having a first surface 451 and a second surface 452, and an engaging portion 454 that protrudes from the half body 453 in a direction toward the insulating member 7 (upward in Figure 4A) and engages with the insulating member 7.

[0049] The piece main body 453 extends from one end of the extended side surface portion 44 in the Z-axis direction along the closed portion 121 of each energy storage element 10 in the Y-axis direction and also in the X-axis direction (see FIG. 5).

[0050] The engaging portion 454 is a protruding portion that protrudes toward the energy storage device 10 from an intermediate region 450 excluding each end portion in the X-axis direction and the Y-axis direction of the piece main body 453. The engaging portion 454 extends in the Z-axis direction.

[0051] In the extended bottom portion 45 of this embodiment, the first surface that faces the multiple storage elements 10 in the Z-axis direction of the half body 453 constitutes the first surface 451 of the extended bottom portion 45, and the second surface that is the back surface of the first surface of the half body 453 constitutes the second surface 452 of the extended bottom portion 45.

[0052] In the extended bottom surface portion 45 of this embodiment, multiple engaging portions 454, for example, two engaging portions 454, are provided with a gap between them in the X-axis direction. Note that one engaging portion 454 may be provided on the extended bottom surface portion 45. The engaging portion 454 is a plate-shaped portion (for example, a rectangular plate-shaped portion).

[0053] One end of the engaging portion 454 in the Z-axis direction engages with the insulating member 7. Specifically, the engaging portion 454 has a base portion 455 connected to the piece main body 453, a tip portion 456 that engages with the insulating member 7, and a connecting portion 457 that connects the base portion 455 and the tip portion 456. In this engaging portion 454, the base portion 455, the connecting portion 457, and the tip portion 456 are continuously arranged in order from the side farthest from the energy storage element 10 in the Z-axis direction.

[0054] The base portion 455 and the tip portion 456 are each a flat portion extending in the X-axis direction and the Y-axis direction (see FIG. 6 ). The connection portion 457 is a flat portion extending at an angle relative to the base portion 455 and the tip portion 456. The connection portion 457 is disposed with a gap in the Z-axis direction relative to the piece main body 453.

[0055] The extended top surface portion 46 extends from the other end of the extended side surface portion 44 in the Z-axis direction along the Y-axis direction and the X-axis direction along the cover plate 13 of each energy storage element 10. The extended top surface portion 46 is a long strip in the X-axis direction, and has a constant dimension (width) in the Y-axis direction at each position except for both ends in the X-axis direction. The width of this extended top surface portion 46 is smaller than the width of the extended bottom surface portion 45 (see FIG. 3 ).

[0056] The insulating member 7 has insulating properties. The insulating member 7 is disposed between the extension member 42 and the plurality of energy storage elements 10. The energy storage device 1 of this embodiment includes a pair of insulating members 7, each of which covers at least an area of ​​the extension member 42 that faces the plurality of energy storage elements 10. As a result, each insulating member 7 provides insulation between the extension member 42 and the plurality of energy storage elements 10.

[0057] Specifically, as shown in Figures 2 and 7 to 10, the insulating member 7 has an insulating side portion (second main body portion) 70 that extends along the extended side portion 44 of the extension member 42 between the multiple storage elements 10 and the extended side portion 44, and an insulating bottom portion (second piece portion) 71 that is connected to the end of the insulating side portion 70 in the Z-axis direction and extends along the extended bottom portion 45 between the multiple storage elements 10 and the extended bottom portion 45.

[0058] In the insulating member 7 of this embodiment, the insulating bottom surface portion 71 extends from one end in the Z-axis direction of the insulating side surface portion 70. The insulating member 7 has an insulating top surface portion 72 that extends in the Y-axis direction from the end in the Z-axis direction of the insulating side surface portion 70 that is perpendicular to the Y-axis direction, and also extends in the X-axis direction that is perpendicular to both the Y-axis direction and the Z-axis direction.

[0059] The insulating side surface portion 70 faces the short wall portion 124 of each energy storage element 10. The insulating side surface portion 70 is plate-shaped and extends along the short wall portion 124 of each energy storage element 10, and has through holes 700 of a size and shape corresponding to the through holes 440 of the extended side surface portion 44 at positions corresponding to the through holes 440 of the extended side surface portion 44 of each insulating member 7. The insulating side surface portion 70 is sandwiched between the short wall portion 124 of the energy storage element 10 and the extended side surface portion 44 of the extension member 42 in the Y-axis direction.

[0060] The insulating top surface portion 72 extends from the other end of the insulating side surface portion 70 in the Z-axis direction along the Y-axis direction and the X-axis direction along the cover plate 13 of each energy storage element 10. The insulating top surface portion 72 is a long strip in the X-axis direction, and has a constant dimension (width) in the Y-axis direction at each position except for both ends in the X-axis direction. The width of the insulating top surface portion 72 is smaller than the width of the insulating bottom surface portion 71, as shown in FIG. 11 .

[0061] The insulating top surface portion 72 has a first portion 720 that is continuous with the other end of the insulating side surface portion 70 in the Z-axis direction, a second portion 721 that, together with the first portion 720, covers the front and back surfaces of the extended top surface portion 46, and a third portion 722 that connects the first portion 720 and the second portion 721 and covers the edge of the extended top surface portion 46.

[0062] The insulating bottom surface portion 71 extends in the Y-axis direction and in the X-axis direction from one end of the insulating side surface portion 70 in the Z-axis direction along the blocking portion 121 of each energy storage element 10. The insulating bottom surface portion 71 is strip-shaped and long in the X-axis direction, and has a constant dimension (width) in the Y-axis direction at each position except for both ends in the X-axis direction. The insulating bottom surface portion 71 has a first surface 711 that faces the multiple energy storage elements 10 in the Z-axis direction, and a second surface 712 that is the back surface of the first surface 711.

[0063] In the insulating member 7 of this embodiment, the first surface 711 of the insulating bottom surface portion 71 is a flat surface. The second surface 712 of the insulating bottom surface portion 71 is an uneven surface, as shown in Fig. 9 . Specifically, the insulating bottom surface portion 71 has a rib 7120 that extends in the Y-axis direction and protrudes in a direction away from the energy storage device 10 in the Z-axis direction. A plurality of these ribs 7120 are provided at intervals in the X-axis direction.

[0064] The direction from the piece main body 453 toward the insulating bottom surface portion 71 coincides with the protruding direction (upward in FIG. 4A ) of the engaging portion 454. The insulating bottom surface portion 71 engages with the engaging portion 454.

[0065] The insulating bottom surface portion 71 engages with the extended bottom surface portion 45 (see FIG. 4A ). Specifically, the extended bottom surface portion 45 and the insulating bottom surface portion 71 engage to restrict movement of the extended bottom surface portion 45 and the insulating bottom surface portion 71 away from each other (in the Z-axis direction). In this energy storage device 1, the insulating bottom surface portion 71 engages with the extended bottom surface portion 45 in an intermediate region 450 excluding each end of the extended bottom surface portion 45 in the Y-axis direction and the X-axis direction (see FIG. 5 ). The insulating bottom surface portion 71 engages with the extended bottom surface portion 45 in the intermediate region 450 in the X-axis direction and the Y-axis direction in the region where a stack of multiple energy storage elements 10 and multiple adjacent members 2 is provided. Specifically, when the fixed position of extension member 42 is considered as the reference, insulating bottom portion 71 engages with extended bottom portion 45 in a region excluding each end in the X-axis direction and each end in the Y-axis direction between the position where insulating member 7 and extension member 42 are fixed with first fastening member B and the position where end member 41 and extension member 42 are fixed with connecting member 43. When adjacent member 2 is considered as the reference, insulating bottom portion 71 engages with extended bottom portion 45 in a region excluding each end in the X-axis direction and each end in the Y-axis direction between the position of second adjacent member 2B and the position of third adjacent member 2C.

[0066] Specifically, the insulating bottom surface portion 71 is disposed between the plurality of energy storage elements 10 and the extended bottom surface portion 45 in a state where it does not extend beyond the second surface 452 in a direction from the insulating bottom surface portion 71 toward the extended bottom surface portion 45 (downward in FIG. 4A ) (a state where it is positioned closer to the energy storage elements 10 in the Z-axis direction than the second surface 452). More specifically, the entire insulating bottom surface portion 71 is covered by the extended bottom surface portion 45 from a position far from the energy storage elements 10 in the Z-axis direction. The insulating bottom surface portion 71 is sandwiched in the Z-axis direction between the blocking portion 121 of the energy storage elements 10 and the extended bottom surface portion 45 of the extension member 42.

[0067] In the insulating member 7 of this embodiment, the insulating bottom surface portion 71 has an accommodating portion 710 at its extended end portion that accommodates the tip portion 456 of the engaging portion 454. As shown in FIG. 7 , a plurality of accommodating portions 710, for example, two accommodating portions 710, are arranged at intervals in the X-axis direction.

[0068] The accommodation portion 710 is a bag-shaped portion that covers the engaging portion 454. The dimension of the accommodation portion 710 in the X-axis direction is slightly larger than the dimension of the engaging portion 454 in the X-axis direction. The engaging portion 454 is inserted into the accommodation portion 710 in the Y-axis direction. The accommodation portion 710 of this embodiment has a pair of covering portions 713 that cover the tip portion 456 from both sides in the Z-axis direction, and a connecting rib 714 that connects the pair of covering portions 713 (one covering portion 715 and the other covering portion 716) of the rib 7120 and covers the side surface of the tip portion 456. The accommodation portion 710 has an extension portion 717 that extends from the other covering portion 716 in the Z-axis direction so as to be away from the energy storage device 10.

[0069] One of the pair of covered portions 713, the covered portion 715, is located closer to the energy storage device 10 in the Z-axis direction. The other of the pair of covered portions 713, the covered portion 716, is located farther from the energy storage device 10 in the Z-axis direction. In each housing portion 710, the other covered portions 716 are arranged in pairs with a gap in the X-axis direction. As shown in FIGS. 8 and 10 , the covered portions 716 are composed of two opposing pieces that are arranged so as to approach each other from one tip in the Z-axis direction of two ribs 7120 adjacent in the X-axis direction toward one side and the other side in the X-axis direction. Note that the tips of these two covered portions 716 in the X-axis direction are not in contact with each other but are spaced apart, and a slit-like gap is formed between the two covered portions 716. This prevents shrinkage in the housing portion 710 when the insulating member 7 is molded from a resin material. 4A and 7 to 9, the covering portion 716 is formed from the center of the insulating bottom surface portion 71 in the Y-axis direction to the tip on the side away from the insulating side surface portion 70, but is not formed from the center of the insulating bottom surface portion 71 in the Y-axis direction to the side approaching the insulating side surface portion 70. The tip portion 456 of the engaging portion 454 is inserted into the accommodating portion 710 along the Y-axis direction from the region where the covering portion 716 is not formed.

[0070] The extension portion 717 is adjacent in the Y-axis direction to the piece main body 453 of the extended bottom surface portion 45. The extension portion 717 extends along the periphery of the extended bottom surface portion 45 from one end to the other end in the X-axis direction.

[0071] According to the above-described energy storage device 1, the extended bottom surface portion 45 of the extension member 42 and the insulating bottom surface portion 71 of the insulating member 7 are engaged with each other, thereby suppressing movement of the insulating bottom surface portion 71 relative to the extended bottom surface portion 45. In the energy storage device 1 of this embodiment, the extended bottom surface portion 45 and the insulating bottom surface portion 71 are engaged to restrict movement in the Z-axis direction, thereby suppressing movement of the insulating bottom surface portion 71 in the Z-axis direction relative to the extended bottom surface portion 45. By suppressing movement of the insulating bottom surface portion 71 in the Z-axis direction relative to the extended bottom surface portion 45, it is possible to suppress lifting of the insulating bottom surface portion 71 relative to the extended bottom surface portion 45 during manufacturing of the energy storage device 1.

[0072] In the energy storage device 1 of this embodiment, the engagement between the engaging portion 454 and the accommodation portion 710 cannot prevent relative movement between the extended bottom surface portion 45 and the insulating bottom surface portion 71 in the X-axis direction or the Y-axis direction, but the relative movement in the Y-axis direction is prevented because the extending portion 717 of the insulating bottom surface portion 71 is adjacent to the piece main body 453 of the extended bottom surface portion 45 in the Y-axis direction. The extending portion 717 extends from one end to the other end in the X-axis direction along the periphery of the extended bottom surface portion 45, so the relative movement in the X-axis direction is prevented.

[0073] In the energy storage device 1 of this embodiment, the extended bottom surface portion 45 and the insulating bottom surface portion 71 are engaged in an intermediate region 450 excluding each end portion of the extended bottom surface portion 45 in the Y-axis direction and the X-axis direction, and therefore movement of the insulating bottom surface portion 71 in this intermediate region 450 is effectively suppressed.

[0074] In the energy storage device 1 of this embodiment, the insulating bottom surface portion 71 is arranged between the multiple energy storage elements 10 and the extended bottom surface portion 45 without exceeding the second surface 452 of the extended bottom surface portion 45 in the Z-axis direction. Therefore, compared to the configuration shown in Figure 4B in which a portion of the insulating bottom surface portion 71 exceeds the second surface 452 of the extended bottom surface portion 45, the dimension of the energy storage device 1 in the Z-axis direction can be reduced by the dimension L of the portion exceeding the second surface 452 (i.e., the size can be reduced in the Z-axis direction).

[0075] In the energy storage device 1 of this embodiment, a simple configuration in which the engaging portion 454 protruding from the half body 453 of the extended bottom surface portion 45 engages with the insulating bottom surface portion 71 can easily be realized, allowing the extended bottom surface portion 45 and the insulating bottom surface portion 71 to engage with each other without any portion of the insulating bottom surface portion 71 exceeding the second surface 452 of the extended bottom surface portion 45.

[0076] The energy storage device 1 of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. The configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Part of the configuration of one embodiment can be deleted.

[0077] In the above embodiment, the extended bottom surface portion 45 and the insulating bottom surface portion 71 are engaged in the intermediate region 450 excluding each end portion of the extended bottom surface portion 45 in the Y-axis direction and the X-axis direction, but the extended bottom surface portion 45 and the insulating bottom surface portion 71 may be engaged at each end portion of the extended bottom surface portion 45 in the Y-axis direction and the X-axis direction. In this case, the extended bottom surface portion 45 and the insulating bottom surface portion 71 can be engaged at both end portions of the extended bottom surface portion 45 in the Y-axis direction and both end portions of the extended bottom surface portion 45 in the X-axis direction.

[0078] In the above embodiment, the insulating bottom surface portion 71 was positioned between the multiple storage elements 10 and the extended bottom surface portion 45 so that it did not exceed the second surface 452 of the extended bottom surface portion 45 in the Z-axis direction, but it can also be positioned between the multiple storage elements 10 and the extended bottom surface portion 45 so that a portion of the insulating bottom surface portion 71 exceeds the second surface 452 of the extended bottom surface portion 45.

[0079] In the above embodiment, the engaging portion 454 protruding from the piece main body 453 of the extended bottom surface portion 45 is engaged with the insulating bottom surface portion 71, but the extended bottom surface portion 45 and the insulating bottom surface portion 71 may be engaged with each other in other ways. An engaging portion protruding from the insulating bottom surface portion 71 may also be engaged with the extended bottom surface portion 45.

[0080] In the above embodiment, the insulating bottom surface portion 71 includes a bag-shaped accommodation portion 710 at the extended end portion that accommodates the tip portion 456 of the engagement portion 454. However, instead of the bag-shaped accommodation portion 710, a band-shaped (annular) accommodation portion may be used. While the engagement portion 454 is inserted into the accommodation portion 710 in the Y-axis direction, the engagement portion 454 may be inserted in another direction (such as the X-axis direction). The accommodation portion 710 may be formed without using the rib 7120 (specifically, the connecting rib 714). In the accommodation portion 710, a pair of covering portions 713 may be connected to the rib 7120 by a connecting portion that is separately provided. While a pair of accommodation portions 710 are provided with a gap in the X-axis direction, a single accommodation portion 710 may be provided, or they may be provided consecutively in the Y-axis direction.

[0081] In the above embodiment, the extended bottom surface portion 45 of the extension member 42 engages with the insulating bottom surface portion 71, but instead of the extended bottom surface portion 45, another portion of the extension member 42 (extended top surface portion 46) may engage with another portion of the insulating member 7 (insulating top surface portion 72).

[0082] In the above embodiment, the members adjacent to the plurality of energy storage devices 10 are members (extension members 42) adjacent in the direction perpendicular to the stacking direction of the energy storage devices 10 (the Y-axis direction), but they may also be members adjacent in the stacking direction (axial direction) of the energy storage devices 10 (the termination members 41 in the above embodiment). Specifically, the termination members 41 engage with the insulating member 7. More specifically, the termination members 41 have a rectangular plate shape (a termination main body portion (first main body portion) extending in a direction perpendicular to the Y-axis direction) corresponding to the size of the energy storage devices 10, and a termination bottom surface portion (first piece portion) extending in the Y-axis direction from the end of the termination main body portion in the Z-axis direction and extending in the X-axis direction perpendicular to both the Y-axis direction and the Z-axis direction. The insulating member 7 is disposed between the termination member (the termination main body portion and the insulating bottom surface portion) and the stack of energy storage devices 10, and has a first portion disposed between the termination main body portion and the stack of energy storage devices 10, and a second portion disposed between the termination bottom surface portion and the stack. The bottom end portion and the second portion of the insulating member 7 are engaged with each other.

[0083] In the above embodiment, the energy storage device includes a rectangular cylindrical energy storage element. However, a laminated energy storage element may also be included. A laminated energy storage element includes, instead of a case, a sealed container made of laminate film that houses an electrode assembly together with an electrolyte. The outline of this laminated energy storage element when viewed from the X-axis direction includes a first side extending along the Z-axis direction and a second side adjacent to the first side and extending along the Y-axis direction. This first side, together with the extended side surface portion 44 of the extension member 42, sandwiches the insulating side surface portion 70 of the insulating member 7 in the Y-axis direction. This second side, together with the extended bottom surface portion 45 of the extension member 42, sandwiches the insulating bottom surface portion 71 of the insulating member 7 in the Z-axis direction.

[0084] In the above embodiment, the case where the energy storage element is used as a chargeable and dischargeable non-aqueous electrolyte secondary battery (e.g., a lithium ion secondary battery) has been described, but the type and size (capacity) of the energy storage element are arbitrary. In the above embodiment, a lithium ion secondary battery has been described as an example of the energy storage element, but the present invention is not limited to this. The present invention is also applicable to energy storage elements of various secondary batteries, as well as primary batteries and capacitors such as electric double layer capacitors.

[0085] REFERENCE SIGNS LIST 1...Electricity storage device, 2...Adjacent member, 2A...First adjacent member (adjacent member), 2B...Second adjacent member (adjacent member), 2C...Third adjacent member (adjacent member), 4...Retaining member, 7...Insulating member, 8...Bus bar, 10...Electricity storage element, 11...Case, 12...Case body, 13...Cover plate, 14...External terminal, 41...Termination member, 42...Extension member, 43...Connecting member, 44...Extended side portion (first main body portion), 45...Extended bottom portion (first piece portion), 46...Extended top surface portion, 47...Extended end surface portion, 70...Insulating side portion (second main body portion), 71...Insulating bottom surface portion (second piece portion), 72...Insulating top surface portion, 121...Blocking portion, 122...Body portion (circumferential wall), 123...Long wall portion, 124...Short wall portion, 440...Through hole, 450...Intermediate region, 451 ...First surface, 452...Second surface, 453...Strip main body, 454...Engagement portion, 455...Base portion, 456...Tip portion, 457...Connection portion, 500...Power supply device, 501...Battery cell, 502...Battery stack, 502...Battery cell, 503...End plate, 504...Bind bar, 505...Separator, 506...Main plate, 507...Fastening main surface, 508...First folded piece, 509...Second folded piece, 510...Third folded piece, 511...Fourth folded piece, 512...Insulating material, 700...Through hole, 710...Accommodating portion, 711...First surface, 712...Second surface, 713, 715, 716...Coated portion, 714...Connection rib, 720...First portion, 721...Second portion, 722...Third portion, 7120...Rib, B...First fastening member

Claims

1. A plurality of storage elements; an extension member adjacent to the plurality of energy storage elements in a first direction; an insulating member disposed between the plurality of energy storage elements and the extension member, the extension member has a first body portion and a first piece portion; the first body portion extends in a second direction intersecting the first direction and a third direction intersecting both the first direction and the second direction; the first piece portion extends in the first direction from an end portion of the first main body portion in the second direction and also extends in the third direction; the first body portion and the first arm portion are each disposed along the plurality of energy storage elements, the insulating member has a second body portion and a second piece portion, the second body portion extends along the first body portion between the plurality of energy storage elements and the first body portion, the second arm portion is connected to an end of the second body portion in the second direction between the plurality of energy storage elements and the first arm portion and extends along the first arm portion; The first piece and the second piece are engaged with each other.

2. The power storage device according to claim 1 , wherein the first arm and the second arm are engaged with each other in an intermediate region of the first arm excluding an end portion in the first direction and an end portion in the third direction.

3. the first arm portion has a first surface facing the plurality of energy storage elements in the second direction and a second surface that is a reverse surface of the first surface, The energy storage device according to claim 1 or 2, wherein the second arm is arranged between the plurality of energy storage elements and the first arm so as not to extend beyond the second surface in a direction from the second arm toward the first arm.

4. The first piece includes a piece body having the first surface and the second surface; The power storage device according to claim 3 , further comprising: an engaging portion that protrudes from the arm body in a direction toward the second arm and engages with the second arm.