Power storage device

Abstract

This power storage device comprises: a laminate obtained by stacking a plurality of power storage elements in a first direction; two end members arranged overlapping with two ends of the laminate in the first direction; and a plurality of connecting members attached to the two end members at the two ends of the laminate in the first direction. At least one of the two end members comprises: a plate member arranged at the power storage element side of the end member in the first direction; and a frame member that sandwiches, in the first direction, the plate member between frame member and the power storage elements, that comprises a plurality of attachment sections to which ends of the plurality of connecting members in the first direction are attached, and that comprises a plurality of coupling sections extending in a direction orthogonal to the first direction and coupling the attachment sections together.

Description

Power storage device

[0001] The present invention relates to a power storage device. The present application claims priority based on Japanese Patent Application No. 2025-049507 filed on March 25, 2025, the content of which is incorporated herein by reference.

[0002] Patent Document 1 discloses a power storage device including a stacked body (battery block) formed by stacking a plurality of power storage elements (battery blocks), two end members (end plates), and two side plate members (restraining members).

[0003] Japanese Unexamined Patent Publication No. 2016-046233

[0004] In this type of power storage device, since a plurality of power storage elements are sandwiched between two end members, each end member is required to have a function of receiving the reaction force generated by sandwiching the plurality of power storage elements. For this reason, the end members tend to be thick, resulting in a problem that the power storage device becomes heavy.

[0005] An aspect of the present invention provides a power storage device that can achieve weight reduction.

[0006] A power storage device according to one aspect of the present invention includes: a stacked body in which a plurality of power storage elements are stacked in a first direction; two end members disposed to overlap both ends of the stacked body in the first direction; and a plurality of connecting members each extending in the first direction and attached to the two end members at both ends of the stacked body in the first direction, wherein at least one of the two end members has the first direction as a thickness direction, and includes: a plate member disposed on the power storage element side in the first direction of the end member; and a frame member having a plurality of mounting portions to which ends of the plurality of connecting members in the first direction are attached, and a plurality of connecting portions extending in a direction orthogonal to the first direction to connect the mounting portions to each other, the frame member sandwiching the plate member between itself and the power storage element in the first direction.

[0007] According to an aspect of the present invention, weight reduction of the power storage device can be achieved.

[0008] This is a perspective view of the energy storage device according to the embodiment. This is an exploded perspective view of the energy storage device according to the embodiment. This is a perspective view of the end member according to the embodiment. This is an exploded perspective view of the end member according to the embodiment. This is a schematic plan view of the energy storage element, separator and plate body according to the embodiment as seen from the X direction. This is a schematic side view of the energy storage element, separator and plate body according to the embodiment as seen from the Y direction.

[0009] (1) An energy storage device according to one aspect of the present invention comprises a laminate in which a plurality of energy storage elements are stacked in a first direction, two end members arranged in overlapping positions at both ends of the laminate in the first direction, and a plurality of connecting members each extending in the first direction and attached to the two end members at both ends of the laminate in the first direction, wherein at least one of the two end members has a plate member with the first direction as the thickness direction and positioned on the energy storage element side in the first direction, a plurality of mounting portions to which the ends of the plurality of connecting members in the first direction are attached, and a plurality of connecting portions extending in a direction perpendicular to the first direction and connecting the mounting portions to each other, and a frame member that sandwiches the plate member between itself and the energy storage elements in the first direction.

[0010] According to one aspect of the present invention, the portion of the end member that needs to be reinforced to withstand the reaction force (hereinafter referred to as "laminated body reaction force") generated when the laminate (multiple energy storage elements) is sandwiched can be made solely of a frame member, thus allowing the plate member to be made lightweight. As a result, the end member can be made lightweight, thereby reducing the weight of the energy storage device. Furthermore, by providing a plate member located on the energy storage element side of the end member, the laminate can be stably supported from a first direction by the end member.

[0011] (2) In the energy storage device described in (1) above, the plurality of connecting parts may be formed in the shape of a rod or a strip and connect the mounting parts to each other.

[0012] In the energy storage device described in (2) above, the connecting portion is made rod-shaped or strip-shaped, thereby reducing the weight of the frame members including the connecting portion, while the frame members can withstand the reaction force of the laminate.

[0013] (3) In the energy storage device described in (1) or (2) above, the plate member may have a flat plate body with the first direction as the thickness direction, and ribs that protrude from the plate body in the first direction and extend in a direction perpendicular to the first direction.

[0014] In the energy storage device described in (3) above, the plate body is reinforced by ribs, which suppresses the bending of the plate body in response to the reaction force of the laminate.

[0015] (4) In the energy storage device described in (3) above, the ribs may extend along the periphery of the plate member.

[0016] In the energy storage device described in (4) above, the peripheral portion of the plate body (for example, the entire circumference) is reinforced, thereby suppressing the peripheral portion of the plate body from bending outward in the first direction in response to the reaction force of the laminate.

[0017] (5) In the energy storage device described in (3) or (4) above, the plurality of mounting portions may be arranged at intervals along the periphery of the plate body in the circumferential direction of the plate body when viewed from the first direction, and the ribs may extend along the periphery of the plate body between adjacent mounting portions in the circumferential direction of the plate body when viewed from the first direction.

[0018] According to the energy storage device described in (5) above, the portion of the plate body's periphery where the mounting portion of the frame member is located is reinforced by the mounting portion. In addition, the portion of the plate body's periphery where the mounting portion is not located is reinforced by ribs. By reinforcing the periphery of the plate body in this way, it is possible to suppress the periphery of the plate body from bending outward in the first direction in response to the laminate reaction force, etc.

[0019] (6) In the energy storage device described in any one of (3) to (5) above, the first direction is the thickness direction, and the device further comprises a separator sandwiched between the plate body and the energy storage element in the first direction, wherein the separator is formed to be smaller than the plate body when viewed from the first direction, and is located inside the periphery of the plate body and the energy storage element.

[0020] In the energy storage device described in (6) above, the separator can suppress the expansion of the energy storage element due to charging and discharging by applying a reaction force. In particular, by forming the separator smaller than the plate body, the expansion of the central region of the energy storage element, which is prone to expansion when viewed from the first direction, can be suppressed more effectively.

[0021] (7) In the energy storage device described in any one of (3) to (6) above, the rib may protrude from the plate body toward the outside of the laminate in the first direction.

[0022] In the energy storage device described in (7) above, the ribs do not protrude from the plate body toward the laminate in the first direction. Therefore, the ribs do not obstruct surface contact between the opposing surface of the plate body facing the laminate in the first direction and the energy storage element or separator. Consequently, even if the plate member has ribs, the laminate can be stably supported from the first direction by the end member.

[0023] (8) In the energy storage device described in (7) above, the frame member may be located outside the laminate in the first direction relative to the rib.

[0024] In the energy storage device described in (8) above, the ribs protruding from the plate body toward the outside of the laminate in the first direction do not protrude further outward from the laminate than the frame member. This makes it possible to keep the dimensions of the energy storage device in the first direction small.

[0025] (9) In the energy storage device described in any one of (3) to (8) above, the thickness dimension of the plate body in the first direction may be smaller than the thickness dimension of the frame member in the first direction.

[0026] In the energy storage device described in (9) above, the plate member is even lighter compared to the case where the thickness dimension of the plate body is greater than or equal to the thickness dimension of the frame member, thus further reducing the weight of the energy storage device.

[0027] (10) In the energy storage device described in any one of (1) to (9) above, the connecting portion of the frame member may have a central connecting portion that overlaps with the central region of the plate member when viewed from the first direction.

[0028] In the energy storage device described in (10) above, the central connecting portion of the frame member can suppress or prevent the plate member from bending (flexing) in such a way that the central region of the plate member bulges in response to the reaction force of the laminate.

[0029] [Embodiments] Next, embodiments of the present invention will be described based on the drawings.

[0030] The embodiments described below are all general or specific examples. The shapes, components, arrangement positions of components, and connection configurations shown in the following embodiments are examples only and are not intended to limit the present invention. Dimensions in each figure are not precisely illustrated. In each figure, the same or similar components are denoted by the same reference numerals.

[0031] <Energy Storage Device> Figure 1 is a perspective view of the energy storage device 1. Figure 2 is an exploded perspective view of the energy storage device 1. The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to the outside. The energy storage device 1 is used for power storage or power supply purposes. The energy storage device 1 is used as a battery for driving or starting engines in mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways.

[0032] Examples of the above-mentioned vehicles include electric vehicles (EVs), hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and fossil fuel (gasoline, diesel, liquefied natural gas, etc.) vehicles. Examples of railway vehicles for electric railways include electric trains, monorails, maglev trains, and hybrid trains equipped with both diesel engines and electric motors. The energy storage device 1 can also be used as a stationary battery for household or commercial use, etc.

[0033] As shown in Figures 1 and 2, the energy storage device 1 mainly comprises a laminate 3, two end members 4, a plurality of connecting members 5, 6 (side plate members 5, bind bars 6), and a separator 7. The laminate 3 is constructed by stacking flat rectangular parallelepiped energy storage elements 2 in the thickness direction. The energy storage elements 2 are formed in a rectangular shape when viewed from the thickness direction.

[0034] In the following description, the thickness direction of the energy storage element 2 is referred to as the X direction. The longitudinal direction of the energy storage element 2 when viewed from the thickness direction is referred to as the Y direction. The short direction of the energy storage element 2 when viewed from the thickness direction is referred to as the Z direction. These X, Y, and Z directions are mutually orthogonal directions. The X direction is an example of the "first direction" in this invention. The Y and Z directions are examples of "directions orthogonal to the first direction" in this invention. The Y direction may also be referred to as the left-right direction. The Z direction may also be referred to as the up-down direction. Depending on how the energy storage device 1 is used, the Z direction may not be the up-down direction, but in this embodiment, for the sake of explanation, the Z direction will be described as the up-down direction.

[0035] Expressions indicating relative directions or orientations, such as parallel and orthogonal, can, strictly speaking, include cases where the directions or orientations are not exactly parallel. For example, two directions being parallel does not only mean that these two directions are perfectly parallel, but also that they are substantially parallel, meaning they may have a difference of, for example, a few percent.

[0036] The energy storage element 2 is a secondary battery (single cell) that can charge and discharge electricity. Specifically, the energy storage element 2 is a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. However, the energy storage element 2 may be a secondary battery other than a non-aqueous electrolyte secondary battery, or it may be a capacitor. The energy storage element 2 may be a primary battery instead of a secondary battery. The energy storage element 2 may be a battery using a solid electrolyte. The energy storage element 2 may be a pouch-type battery.

[0037] As shown in Figure 2, each energy storage element 2 has an element body 21 formed in the shape of a flat rectangular parallelepiped, and terminals 22 and a gas discharge valve 23 arranged on the outer surface of the element body 21. Although not shown, the element body 21 is constructed by housing electrode bodies in a flat rectangular parallelepiped case.

[0038] Terminals 22 are arranged one at each end face of the element body 21 in the Y direction. The two terminals 22 are a positive terminal 22 and a negative terminal 22. The gas discharge valve 23 may be arranged on only one end face of the element body 21 in the Y direction, or on both end faces. The gas discharge valve 23 releases the pressure inside the element body 21 when the pressure rises and discharges gas and other waste to the outside of the element body 21 (energy storage element 2).

[0039] In the laminate 3, the terminals 22 of the multiple energy storage elements 2 and the gas discharge valves 23 are arranged sequentially toward one side (downward) in the Z direction on both sides 3c of the laminate 3 in the Y direction. Therefore, the terminals 22 of the multiple energy storage elements 2 are aligned in the X direction in the region on the other side (upper) in the Z direction of both sides 3c of the laminate 3. The gas discharge valves 23 of the multiple energy storage elements 2 are aligned in the X direction in the region on one side (downward) in the Z direction of both sides 3c of the laminate 3. "Side 3c of the laminate 3 in the Y direction" corresponds to the end face of the element body 21 in the Y direction as described above.

[0040] Although not shown in the diagram, the laminate 3 may include spacers in addition to the multiple energy storage elements 2. The spacers are placed between adjacent energy storage elements 2 in the X direction, and between the outermost energy storage element 2 in the X direction and the end member 4.

[0041] As shown in Figures 1 and 2, the stacked body 3 is provided with bus bar plates 8 connected to terminals 22 of the plurality of power storage elements 2. The plurality of power storage elements 2 arranged in the X direction are connected in series or in parallel by the bus bar plates 8. The specific arrangement and the like of the bus bar plates 8 may be arbitrary. In the present embodiment, the bus bar plates 8 are arranged on both sides of the stacked body 3 in the Y direction. The two bus bar plates 8 are arranged on the other side (upper side) in the Z direction of the stacked body 3 so as to correspond to the terminals 22 of the plurality of power storage elements 2, and extend in the X direction. Each bus bar plate 8 includes a plurality of bus bars 81 electrically and physically connected to the terminals 22 of the power storage element 2. The plurality of bus bars 81 are arranged in the X direction on each bus bar plate 8.

[0042] External connection terminals 9 electrically connected to the bus bar plates 8 are provided at both ends of the stacked body 3 in the X direction. When the external connection terminals 9 are electrically connected to an external device (not shown), charging and discharging of the stacked body 3 are enabled. The power storage device 1 may include electric devices such as a circuit board and a relay that monitor or control the charge state, discharge state, and the like of the stacked body 3.

[0043] The two end members and the plurality of connection members 5, 6 are used to constrain the stacked plurality of power storage elements 2 and maintain the stacked state of the stacked body 3.

[0044] The two end members 4 are arranged at both ends of the stacked body 3 in the X direction. Therefore, the two end members 4 sandwich the stacked plurality of power storage elements 2 from the stacking direction (the X direction) thereof. Both of the two end members 4 have a plate-shaped appearance with the X direction as the thickness direction. In the present embodiment, both of the two end members 4 are formed into a rectangular shape having a size corresponding to the outer shape of the power storage element 2 when viewed from the X direction. Details of the end members 4 will be described later.

[0045] The plurality of connecting members 5, 6 each extend in the X direction. Each connecting member 5, 6 is attached to the two end members 4 at both ends of the stacked body 3 in the X direction, and connects the two end members 4. Specific aspects of the connecting members 5 and 6 are not particularly limited. In the present embodiment, the connecting members 5, 6 include two side plate members 5 and two bind bars 6.

[0046] The two side plate members 5 are located on both sides of the stacked body 3 in the Y direction, and each extend in the X direction. Both end portions of the side plate member 5 in the X direction are fixed (physically connected) to the two end members 4 by fastening members such as bolts (not shown). Each side plate member 5 is formed in a plate shape whose thickness direction is mainly the Y direction, and includes a member main body 51 facing the side surface 3c of the stacked body 3 in the Y direction, an upper piece 52 bent and extended from the upper edge of the member main body 51 toward the stacked body 3 side, and a lower piece 53 bent and extended from the lower edge of the member main body 51 toward the stacked body 3 side.

[0047] The member main body 51 is formed to extend in the X direction and overlaps the side surface 3c side of the stacked body 3. When viewed from the Y direction, the member main body 51 overlaps the terminals 22 and gas discharge valves 23 of the plurality of power storage elements 2 arranged in the X direction. The member main body 51 has attachment pieces 55 located at both ends in the X direction. The attachment pieces 55 are fixed to the end member 4 by fastening members such as bolts (not shown).

[0048] As shown in FIG. 1 and FIG. 2, the member main body 51 of the present embodiment includes a plurality of openings 561 penetrating in the Y direction and arranged in the X direction, and a bus bar cover 562 that closes the plurality of openings 561. In the illustrated example, the plurality of openings 561 are arranged at equal intervals in the X direction, but the arrangement is not limited thereto. The bus bar cover 562 is disposed on a surface of the member main body 51 facing the stacked body 3 side, and is formed to extend in the X direction. The plurality of openings 561 and the bus bar cover 562 are positioned so as to overlap the terminals 22 of the plurality of power storage elements 2 arranged in the X direction when viewed from the Y direction. Note that the member main body 51 does not necessarily need to have the plurality of openings 561, for example.

[0049] The upper piece 52 of the side plate member 5 overlaps the upper surface 3a of the laminate 3. The lower piece 53 of the side plate member 5 overlaps the lower surface 3b of the laminate 3. The upper piece 52 and the lower piece 53 each have mounting pieces 57 and 58 located at both ends in the X direction. Each mounting piece 57 and 58 is fixed to the end member 4 by fastening members (not shown) such as bolts.

[0050] The two bind bars 6 are positioned on both sides of the laminate 3 in the Z direction. Each bind bar 6 is located in the center of the laminate 3 in the Y direction. Each bind bar 6 has a strip-shaped bind bar body 61 that extends across the entire laminate 3 in the X direction, and mounting pieces 62 integrally formed at both ends of the bind bar body 61 in the X direction.

[0051] The width dimension of the bind bar body 61 in the Y direction is sufficiently smaller than the width dimension of the laminate 3 in the Y direction. By forming the bind bar body 61 in this manner, the area of ​​the surface (upper surface 3a, lower surface 3b) of the laminate 3 that is exposed on both sides in the Z direction can be increased, thereby improving the heat dissipation performance of the laminate 3.

[0052] Each of the two mounting pieces 62 of each bind bar 6 is formed in an L-shape when viewed from the Y direction. As a result, a portion of each mounting piece 62 overlaps with the outside of the end member 4 in the X direction. The portion of each mounting piece 62 that overlaps in the X direction is fixed to the end member 4 by fastening members (not shown), such as bolts.

[0053] The two bind bars 6 and the two side plate members 5 described above press the two end members 4 toward the laminate 3 in the X direction. As a result, the two end members 4, the two side plate members 5 and the two bind bars 6 restrain the multiple stacked energy storage elements 2, and the stacked state of the laminate 3 is maintained.

[0054] Next, the end member 4 will be described further. As shown in Figures 2 to 4, the end member 4 has the thickness direction in the X direction and comprises a plate member 41 positioned on the energy storage element 2 side in the X direction of the end member 4, and a frame member 42 that sandwiches the plate member 41 between itself and the energy storage element 2 in the X direction. The material constituting the plate member 41 and the frame member 42 may be arbitrary, but in this embodiment it is a metal material such as iron.

[0055] As shown in Figures 3, 4, and 6, the plate member 41 has a flat plate body 43 with the X direction as the thickness direction, and ribs 44 that protrude from the plate body 43 in the X direction.

[0056] As shown in Figure 5, the plate body 43 is formed in a rectangular shape, with a size that mainly corresponds to the outer shape of the energy storage element 2 when viewed from the X direction. In Figure 5, the plate body 43 is shown to be slightly larger than the energy storage element 2, but it may be slightly smaller than the energy storage element 2, or it may be exactly the same size as the energy storage element 2, for example.

[0057] As shown in Figures 3 and 4, a notch 431 is formed on the periphery of the plate body 43 as viewed from the X direction. The notch 431 is formed as a recess inward from the periphery of the plate body 43. The notch 431 has a predetermined length in the circumferential direction of the plate body 43 as viewed from the X direction. The notch 431 is positioned so as to overlap with the second mounting portion 452 of the frame member 42, which will be described later, as viewed from the X direction. The periphery of the plate body 43 is divided at the notch 431. The aforementioned "circumferential direction of the plate body 43 as viewed from the X direction" is an example of the "direction perpendicular to the first direction" in the present invention. In Figure 4, the notch 431 is located at both ends (upper and lower ends) of the plate body 43 in the Z direction and in the center of the plate body 43 in the Y direction. The center of the plate body 43 in the Y direction corresponds to the center of the laminate 3 in the Y direction.

[0058] The ribs 44 extend in a direction perpendicular to the X direction. In this embodiment, the ribs 44 extend along the periphery of the plate body 43 as viewed from the X direction. The ribs 44 are formed over almost the entire periphery of the plate body 43. The ribs 44 are generally divided at the notches 431, similar to the periphery of the plate body 43. As a result, the ribs 44 are spaced apart along the periphery of the plate body 43 as viewed from the X direction. The second mounting portion 452 of the frame member 42, which will be described later, is located between adjacent ribs 44 in the circumferential direction of the plate body 43. In Figure 4, the ribs 44 are spaced apart in the circumferential direction of the plate body 43 with respect to the notches 431 located at the upper end of the plate body 43, but they may be located without spacing from the notches 431 located at the upper end of the plate body 43, for example.

[0059] As shown in Figure 6, in this embodiment, the ribs 44 protrude from the plate body 43 toward the outside of the laminate 3 in the X direction. That is, the ribs 44 protrude from the plate body 43 toward the laminate 3 in the X direction.

[0060] As shown in Figures 3 and 4, the rib 44 of this embodiment has a first rib 441 and a second rib 442 whose protrusion height in the X direction is greater than that of the first rib 441. The second rib 442 is located on a portion of both sides of the notch 431 in the Y direction at the upper end of the plate body 43. The second rib 442 is also located in the middle portion in the Z direction of both ends (side ends) of the plate body 43 in the Y direction. The first rib 441 is located on the peripheral edge of the plate body 43 where the rib 44 is formed, in a portion where the second rib 442 is not formed.

[0061] The frame member 42 has a plurality of mounting portions 45, and a plurality of connecting portions 46 that extend in a direction perpendicular to the X direction and connect the mounting portions 45 to each other.

[0062] As shown in Figure 1, mounting pieces 55, 57, 58, and 62 of the connecting members 5 and 6 are attached to the multiple mounting portions 45. In this embodiment, each mounting portion 45 is fixed to the mounting pieces 55, 57, 58, and 62 of the connecting members 5 and 6 by fastening members (not shown), such as bolts. As shown in Figure 3, each mounting portion 45 is arranged on the peripheral edge of the plate body 43 when viewed from the X direction. The multiple mounting portions 45 are arranged at intervals along the periphery of the plate body 43 in the circumferential direction of the plate body 43 when viewed from the X direction. The mounting portion 45 includes a first mounting portion 451 to which mounting pieces 55, 57, and 58 of the side plate member 5 are attached, and a second mounting portion 452 to which mounting piece 62 of the bind bar 6 is attached.

[0063] As shown in Figures 3 and 4, the first mounting portion 451 is formed in the shape of a plate with its thickness in the direction perpendicular to the X direction. The first mounting portion 451 is located at both ends of the plate body 43 in the Y direction, with one at the upper end, one at the side end, and one at the lower end of the plate body 43. As shown in Figure 1, the first mounting portion 451 located at the side end of the plate body 43 is in the shape of a plate with its thickness in the Y direction and is attached to the mounting piece 55 of the member body 51 of the side plate member 5. The first mounting portion 451 located at the upper end of the plate body 43 is in the shape of a plate with its thickness in the Z direction and is attached to the mounting piece 57 of the upper piece 52 of the side plate member 5. The first mounting portion 451 located at the lower end of the plate body 43 is in the shape of a plate with its thickness in the Z direction and is attached to the mounting piece 58 of the lower piece 53 of the side plate member 5.

[0064] As shown in Figures 1, 3, and 4, the second mounting portions 452 are located at the center of the plate body 43 in the Y direction, with one at the upper end and one at the lower end of the plate body 43. Each second mounting portion 452 is plate-shaped with the X direction as the thickness direction and is attached to the mounting piece 62 of the bind bar 6. Each second mounting portion 452 is positioned so as to overlap with the notch 431 of the plate body 43 as described above, when viewed from the X direction. The length of the second mounting portion 452 in the Y direction (circumferential direction of the plate body 43) corresponds to the length of the notch 431 of the plate body 43 in the Y direction. Also, each second mounting portion 452 does not overlap with the rib 44 of the plate body 43 when viewed from the X direction. As a result, the rib 44 of the plate member 41 extends along the periphery of the plate body 43 between adjacent second mounting portions 452 in the circumferential direction of the plate body 43, when viewed from the X direction. In other words, the rib 44 extends along the periphery of the plate body 43 so as to connect adjacent second mounting portions 452 in the circumferential direction of the plate body 43 when viewed from the X direction.

[0065] As shown in Figures 3 and 4, the connecting portion 46 of this embodiment is formed in a plate shape with the X direction as the thickness direction. The connecting portion 46 has a strip-shaped first connecting portion 461 that extends in the Y direction from the middle of the plate member 41 in the Z direction, and strip-shaped second connecting portions 462 that extend from both ends of the first connecting portion 461 in the Y direction to both sides of the first connecting portion 461 in the Z direction. Note that the first connecting portion 461 and the second connecting portion 462 are not limited to being strip-shaped extending in a direction perpendicular to the X direction, but may also be formed in a rod shape extending in a direction perpendicular to the X direction, for example.

[0066] Of the first connecting portion 461, the central portion in the Y direction (excluding the portions at both ends in the Y direction) is a central connecting portion 463 that overlaps with the central region 432 of the plate member 41 (plate body 43) when viewed from the X direction. The central region 432 of the plate member 41 may be a region of any shape, for example, which has a smaller area than the plate body 43, which is roughly rectangular when viewed from the X direction, but whose geometric center coincides with the plate body 43 when viewed from the X direction. In Figure 4, the shape of the central region 432 is rectangular, but it may be a circle or other polygon.

[0067] The aforementioned second mounting portion 452 is located in a continuous line from the central part of the first connecting portion 461 in the Y direction to both sides of the first connecting portion 461 in the Z direction. The thickness direction of the second mounting portion 452 is the same as the thickness direction of the connecting portion 46 (especially the first connecting portion 461), which is the X direction. The aforementioned first mounting portion 451 is located in a continuous line at both ends of the first connecting portion 461 in the Y direction and at both ends of each second connecting portion 462 in the Z direction. Each first mounting portion 451 is bent relative to the first connecting portion 461 and the second connecting portion 462, and extends outward from the laminate 3 in the X direction (see Figure 2). As a result, the thickness direction of each first mounting portion 451 is different from the thickness direction of the connecting portion 46 (Y direction, Z direction).

[0068] The frame member 42 is positioned overlapping the plate member 41 in the X direction so as to contact the tip of the first rib 441 in the protruding direction (X direction). In this embodiment, the frame member 42 overlaps a portion of the first rib 441 that extends in the circumferential direction of the plate body 43, but does not overlap the remaining portion of the first rib 441 in the circumferential direction. Furthermore, when the frame member 42 is overlapping the plate member 41 in the X direction, it does not contact the tip of the second rib 442 of the plate member 41 in the protruding direction (X direction).

[0069] In this state, with the frame member 42 stacked on the plate member 41, the frame member 42 is positioned outside the laminate 3 in the X direction beyond the ribs 44 of the plate member 41. That is, the ribs 44 of the plate member 41 do not protrude outside the laminate 3 beyond the frame member 42 in the X direction. This point will be explained below. As mentioned above, the connecting portion 46 of the frame member 42 overlaps the tip of the first rib 441 of the plate member 41. Therefore, the first rib 441 does not protrude outside the laminate 3 beyond the connecting portion 46. On the other hand, the second rib 442 of the plate member 41 protrudes outside the laminate 3 beyond the connecting portion 46. However, the frame member 42 includes a first mounting portion 451 that extends outside the laminate 3 in the X direction from the connecting portion 46. The second rib 442 does not protrude outside the laminate 3 beyond the first mounting portion 451. Therefore, the ribs 44 of the plate member 41 do not protrude outside the laminate 3 beyond the frame member 42 in the X direction.

[0070] The thickness dimension of the frame member 42 in the X direction is greater than the thickness dimension of the plate body 43 in the X direction. Therefore, the rigidity of the frame member 42 is higher than that of the plate body 43.

[0071] As shown in Figures 2, 5, and 6, the separator 7 is formed in a plate-like or sheet-like shape with the X direction as the thickness direction. The separator 7 is sandwiched between the plate body 43 of the end member 4 and the energy storage element 2 in the X direction. The separator 7 can suppress the expansion of the energy storage element 2 due to charging and discharging with a reaction force. When viewed from the X direction, the separator 7 is formed to be smaller than the plate body 43 and the energy storage element 2, and is located inside the periphery of the plate body 43 and the energy storage element 2. The energy storage device 1 does not necessarily have to include the separator 7.

[0072] As described above, in the energy storage device 1 of this embodiment, at least one of the two end members 4 has a plate member 41 positioned on the energy storage element 2 side in the X direction, with the X direction being the thickness direction, and a frame member 42 sandwiching the plate member 41 between itself and the energy storage element 2 in the X direction. The frame member 42 has a plurality of mounting portions 45 to which the ends of a plurality of connecting members 5, 6 in the X direction are attached, and a plurality of connecting portions 46 that extend in a direction perpendicular to the X direction and connect the mounting portions 45 to each other.

[0073] In this embodiment of the energy storage device 1, the portion of the end member 4 that needs to be reinforced to withstand the reaction force (hereinafter referred to as "laminated reaction force") generated when the laminated body 3 (multiple energy storage elements 2) is sandwiched can be made solely of the frame member 42, allowing the plate member 41 to be made lightweight. As a result, the entire end member 4 can be made lightweight, thereby reducing the weight of the energy storage device 1. Furthermore, by having the end member 4 equipped with a plate member 41 located on the energy storage element 2 side, the laminated body 3 can be stably supported from the X direction by the end member 4.

[0074] Furthermore, in the energy storage device 1 of this embodiment, the multiple connecting parts 46 are formed in the shape of a rod or a strip and connect the mounting parts 45 to each other. In this energy storage device 1 of this embodiment, by making the connecting parts 46 in the shape of a rod or a strip, the frame member 42 including the connecting parts 46 can be made lighter while the frame member 42 can withstand the reaction force of the laminate.

[0075] Furthermore, in the energy storage device 1 of this embodiment, the plate member 41 has a flat plate body 43 with the X direction as the thickness direction, and ribs 44 that protrude from the plate body 43 in the X direction and extend in a direction perpendicular to the X direction. In the energy storage device 1 of this embodiment, since the plate body 43 is reinforced by the ribs 44, it is possible to suppress the bending of the plate body 43 in response to the reaction force of the laminate.

[0076] Furthermore, in the energy storage device 1 of this embodiment, the rib 44 extends along the periphery of the plate member 41. In this energy storage device 1 of this embodiment, the peripheral portion of the plate body 43 is reinforced, which suppresses the peripheral portion of the plate body 43 from bending outward in the X direction of the laminate 3 in response to the laminate reaction force.

[0077] Furthermore, in the energy storage device 1 of this embodiment, the multiple second mounting portions 452 of the frame member 42 are arranged at intervals along the periphery of the plate body 43 in the circumferential direction of the plate body 43, when viewed from the X direction. The ribs 44 of the plate member 41 extend along the periphery of the plate body 43 between adjacent second mounting portions 452 in the circumferential direction of the plate body 43, when viewed from the X direction. In this energy storage device 1 of this embodiment, the portion of the periphery of the plate body 43 where the second mounting portions 452 of the frame member 42 are located is reinforced by the second mounting portions 452. In addition, the portion of the periphery of the plate body 43 where the second mounting portions 452 are not located is reinforced by the ribs 44. By reinforcing the periphery of the plate body 43 in this way, it is possible to suppress the periphery of the plate body 43 from bending outward in the X direction of the laminate 3 in response to laminate reaction forces, etc.

[0078] Furthermore, the energy storage device 1 of this embodiment includes a separator 7 sandwiched between the plate body 43 and the energy storage element 2 in the X direction, with the X direction being the thickness direction. The separator 7 is formed to be smaller than the plate body 43 when viewed from the X direction, and is located inside the periphery of the plate body 43 and the energy storage element 2. In this energy storage device 1 of this embodiment, the separator 7 can suppress the expansion of the energy storage element 2 due to charging and discharging with a reaction force. In particular, because the separator 7 is formed to be smaller than the plate body 43, the expansion of the central region of the energy storage element 2, which is prone to expansion when viewed from the X direction, can be suppressed more effectively.

[0079] Furthermore, in the energy storage device 1 of this embodiment, the ribs 44 protrude from the plate body 43 toward the outside of the laminate 3 in the X direction. In this energy storage device 1 of this embodiment, the ribs 44 do not protrude from the plate body 43 toward the laminate 3 in the X direction. Therefore, the ribs 44 do not obstruct surface contact between the opposing surface of the plate body 43 facing the laminate 3 in the X direction and the separator 7 or energy storage element 2. Thus, even if the plate member 41 has ribs 44, the laminate 3 can be stably supported from the X direction by the end member 4.

[0080] Furthermore, in the energy storage device 1 of this embodiment, the frame member 42 is located outside the laminated body 3 in the X direction, beyond the ribs 44 that protrude outward from the laminated body 3. In this energy storage device 1 of this embodiment, the ribs 44 of the plate member 41 do not protrude outside the laminated body 3 beyond the frame member 42. This makes it possible to keep the dimensions of the energy storage device 1 in the X direction small.

[0081] Furthermore, in the energy storage device 1 of this embodiment, the thickness dimension of the plate body 43 in the X direction is smaller than the thickness dimension of the frame member 42 in the X direction. In this embodiment of the energy storage device 1, the plate member 41 is even lighter compared to the case where the thickness dimension of the plate body 43 is equal to or greater than the thickness dimension of the frame member 42, thus further reducing the weight of the energy storage device 1.

[0082] Furthermore, in the energy storage device 1 of this embodiment, the connecting portion 46 of the frame member 42 has a central connecting portion 463 that overlaps with the central region 432 of the plate member 41 when viewed from the X direction. In this energy storage device 1 of this embodiment, the central connecting portion 463 of the frame member 42 can suppress or prevent the plate member 41 from bending (flexing) in response to a laminate reaction force or the like, causing the central region 432 of the plate member 41 to bulge.

[0083] [Modifications] The present invention is not limited to the embodiments described above, and includes various modifications to the embodiments described above, without departing from the spirit of the present invention.

[0084] In the present invention, the ribs 44 of the plate member 41 may extend along the periphery of the plate body 43 between adjacent mounting portions 45 (first mounting portion 451, second mounting portion 452) in the circumferential direction of the plate body 43.

[0085] In the present invention, the ribs 44 constituting the plate member 41 of the end member 4 may include, for example, only the first rib 441 of the above embodiment, or only the second rib 442.

[0086] In the present invention, the ribs 44 of the plate member 41 may protrude, for example, from the plate body 43 toward the inside of the laminate 3 in the X direction, that is, they may protrude from the plate body 43 toward the laminate 3.

[0087] In the present invention, the ribs 44 of the plate member 41 may be formed, for example, around the entire periphery (all around) of the plate body 43.

[0088] In the present invention, the ribs 44 of the plate member 41 are not limited to extending along the periphery of the plate body 43, but may also extend in any direction perpendicular to the X direction in a region of the plate body 43 that is inward from the periphery when viewed from the X direction.

[0089] In the present invention, the end member 4 comprising a plate member 41 and a frame member 42 may be at least one of the two end members 4 constituting the energy storage device 1, and the other end member 4 may not include, for example, a plate member 41 and a frame member 42.

[0090] In the present invention, the laminate 3 only needs to be constructed by stacking at least multiple energy storage elements 2 in the X direction, and the specific form of the laminate 3 is not limited to that of the above embodiment. For example, the two terminals 22 and the gas discharge valve 23 constituting the energy storage element 2 may be arranged on one surface of the element body 21 that faces the same direction. For example, the terminals 22 and gas discharge valves 23 of multiple energy storage elements 2 constituting the laminate 3 may all face the same direction.

[0091] The present invention can be applied to various energy storage devices equipped with energy storage elements such as lithium-ion secondary batteries.

[0092] 1...Energy storage device 2...Energy storage element 3...Laminate 4...End members 5,6...Connecting members 7...Separator 41...Plate member 42...Frame member 43...Plate body 44...Rib 45...Mounting part 46...Connecting part 432...Central region 461...First connecting part 462...Second connecting part 463...Central connecting part

Claims

1. An energy storage device comprising: a laminate formed by stacking a plurality of energy storage elements in a first direction; two end members arranged in overlapping positions at both ends of the laminate in the first direction; and a plurality of connecting members each extending in the first direction and attached to the two end members at both ends of the laminate in the first direction, wherein at least one of the two end members has a plate member with the first direction as the thickness direction and positioned on the energy storage element side in the first direction on the end member; a plurality of mounting portions to which the ends of the plurality of connecting members in the first direction are attached; and a plurality of connecting portions extending in a direction perpendicular to the first direction and connecting the mounting portions to each other; and a frame member that sandwiches the plate member between itself and the energy storage elements in the first direction.

2. The energy storage device according to claim 1, wherein the plurality of connecting parts are formed in the shape of a rod or a strip and connect the mounting parts to each other.

3. The energy storage device according to claim 1, wherein the plate member comprises a flat plate body with the first direction as the thickness direction, and ribs protruding from the plate body in the first direction and extending in a direction perpendicular to the first direction.

4. The energy storage device according to claim 3, wherein the rib extends along the periphery of the plate member.

5. The energy storage device according to claim 3, wherein the plurality of mounting portions are arranged at intervals along the periphery of the plate body as viewed from the first direction, and the ribs extend along the periphery of the plate body between adjacent mounting portions as viewed from the first direction.

6. The energy storage device according to any one of claims 3 to 5, wherein the first direction is the thickness direction, and the device further comprises a separator sandwiched between the plate body and the energy storage element in the first direction, wherein the separator is formed to be smaller than the plate body when viewed from the first direction, and is located inside the periphery of the plate body and the energy storage element.

7. The energy storage device according to any one of claims 3 to 5, wherein the ribs protrude from the plate body toward the outside of the laminate in the first direction.

8. The energy storage device according to claim 7, wherein the frame member is located outside the laminate in the first direction relative to the ribs.

9. The energy storage device according to any one of claims 3 to 5, wherein the thickness dimension of the plate body in the first direction is smaller than the thickness dimension of the frame member in the first direction.

10. The connecting portion of the frame member has a central connecting portion that overlaps with the central region of the plate member when viewed from the first direction, according to any one of claims 1 to 4.

Images