Power storage device

Abstract

Provided is a power storage device comprising: a module in which a plurality of rectangular parallelepiped power storage elements having a dimension in a first direction larger than a dimension in a second direction orthogonal to the first direction are stacked in a third direction orthogonal to the first direction and the second direction; a side member disposed facing first surfaces of the power storage elements orthogonal to the first direction; and an end member disposed facing an end surface of the module in the third direction. The side member is formed to be bent so as to straddle the first surfaces of the power storage elements and second surfaces of the power storage elements orthogonal to the second direction. A fixing part connected to a portion of the side member facing the second surfaces and fixed to the end member is positioned closer to a center part side of the power storage elements than an end part, of the portion facing the second surfaces, on the center part side of the power storage elements, in the first direction.

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. 2025-051637 filed in Japan on March 26, 2025, the content of which is incorporated herein by reference.

[0002] For example, Patent Document 1 discloses a battery pack. The battery pack disclosed in Patent Document 1 includes a battery module and a battery case that accommodates the battery module. Further, in Patent Document 1, the battery module includes a pair of end plates provided at both ends of a cell stack and side plates fixed to the end plates.

[0003] For example, Patent Document 2 discloses a battery module. The battery module disclosed in Patent Document 2 includes two end plates that sandwich a plurality of units, and a restraining member that connects the two end plates.

[0004] Japanese Unexamined Patent Application Publication No. 2019-212395, Japanese Unexamined Patent Application Publication No. 2023-74269

[0005] The present invention provides a power storage device capable of improving the holding rigidity of a plurality of stacked power storage elements.

[0006] As a means for solving the above problems, each aspect of the present invention has the following configuration. A power storage device according to one aspect of the present invention comprises: a module in which a plurality of rectangular parallelepiped power storage elements each having a dimension in a first direction larger than a dimension in a second direction orthogonal to the first direction are stacked and arranged in a third direction orthogonal to the first direction and the second direction; a side member arranged to face a first surface of the power storage element that is orthogonal to the first direction; and an end member arranged to face an end surface of the module in the third direction, wherein the side member is bent so as to straddle the first surface of each power storage element and a second surface of the power storage element that is orthogonal to the second direction, and a fixing portion connected to a portion of the side member facing the second surface and fixed to the end member is located closer to a central portion side of the power storage element in the first direction than an end of the portion facing the second surface on the central portion side of the power storage element.

[0007] According to an aspect of the present invention, it is possible to improve the holding rigidity of a plurality of stacked energy storage elements.

[0008] This is an exploded perspective view showing the schematic configuration of the energy storage device according to this embodiment. This is a perspective view of the energy storage unit of the above energy storage device. This is a front view of the energy storage unit of Figure 2. This is a top view of the energy storage unit of Figure 2. This is a bottom view of the energy storage unit of Figure 2. This is a left side view of the energy storage unit of Figure 2. This is a right side view of the energy storage unit of Figure 2. This is a rear view of the energy storage unit of Figure 2. This is a schematic cross-sectional view of the upper corner. This is a schematic cross-sectional view of the upper corner in a modified example of the energy storage device.

[0009] (1) An energy storage device according to one aspect of the present invention comprises a module in which a plurality of rectangular parallelepiped energy storage elements, the dimensions in a first direction being larger than the dimensions in a second direction perpendicular to the first direction, are stacked in a third direction perpendicular to the first and second directions; a side member positioned opposite to the first surface of the energy storage elements perpendicular to the first direction; and an end member positioned opposite to the end face of the module in the third direction, wherein the side member is formed by bending so as to straddle the first surface of each energy storage element and the second surface of the energy storage element perpendicular to the second direction, and the fixing portion connected to the portion of the side member opposite to the second surface and fixed to the end member is located in the first direction, on the central side of the energy storage element, rather than the end portion on the central side of the portion of the energy storage element opposite to the second surface.

[0010] According to the energy storage device described in (1) above, the side member has a portion facing the second surface of the energy storage element. The fixing portion is located on the central side in the first direction of the energy storage element, rather than the end of the portion of the side member facing the second surface of the energy storage element on the central side of the energy storage element. When each energy storage element expands, the module expands in a third direction. At this time, since the fixing portion is located on the central side in the first direction of the energy storage element, when the fixing portion is pulled in the third direction by the expansion of the module in the third direction, a holding force acts on the side member toward the central part in the first direction. For this reason, according to the energy storage device described in (1) above, it is possible to improve the holding rigidity of the stacked plurality of energy storage elements.

[0011] (2) In the energy storage device described in (1) above, the fixed portion is located on the central side of the energy storage element in the second direction, relative to the second surface of the energy storage element.

[0012] According to the energy storage device described in (2) above, since the fixing portion is located on the central side of the energy storage element rather than the second surface of the energy storage element, the portion of the side member facing the second surface of the energy storage element is pressed against the second surface of the energy storage element when the fixing portion is fixed to the end member. Therefore, according to the energy storage device described in (2) above, the side member can press against both the first and second surfaces of the energy storage element, making it possible to further improve the holding rigidity of the stacked energy storage elements.

[0013] (3) In the energy storage device described in (1) or (2) above, the bent portion of the side member is provided with a low-rigidity portion that has lower rigidity compared to other parts of the bent portion.

[0014] According to the energy storage device described in (3) above, the rigidity of the bent portion of the side member is reduced by the low-rigidity portion compared to the case where the low-rigidity portion is not provided. The bent portion of the side member has higher rigidity compared to the portion facing the first surface and the portion facing the second surface of the energy storage element. By reducing the rigidity of the bent portion in this way, the shape of the side member can be flexibly adapted to the change in the shape of the module when the energy storage element expands. Therefore, according to the energy storage device described in (3) above, the holding force of the side member can be maintained even when the energy storage element expands.

[0015] (4) In the energy storage device described in (3) above, the low-rigidity portion is a hole that penetrates the side member and is arranged in multiple locations along the third direction.

[0016] According to the energy storage device described in (4) above, a low-rigidity portion is formed by a hole that penetrates the side member. Therefore, according to the energy storage device described in (4) above, it is possible to suppress the temperature rise of the energy storage element more effectively than when a low-rigidity portion consisting of a recess is formed in the side member.

[0017] (5) In the energy storage device described in (3) above, the low-rigidity portion is a recess that is recessed from the surface of the side member toward the energy storage element, and a plurality of these portions are arranged along the third direction.

[0018] According to the energy storage device described in (5) above, a low-rigidity portion is formed in the recess created by the recess of the side member. Therefore, compared to the case in which a low-rigidity portion is formed by a through hole, the area in which the energy storage element is exposed can be reduced, and the protective area of ​​the energy storage element can be increased.

[0019] (6) In the energy storage device described in any one of (1) to (5) above, the energy storage element is provided with terminals, and the side member is provided with an opening at a position opposite to the terminals.

[0020] According to the energy storage device described in (6) above of the present invention, the portion of the energy storage element facing the terminals is exposed at the opening of the side member. For this reason, for example, welding work between the terminals and the busbar can be performed through the opening.

[0021] (7) In the energy storage device described in any one of (1) to (6) above, the side member has a connecting portion that connects the portion facing the second surface to the fixing portion, and the dimension of the connecting portion in the third direction is 20% or more of the dimension of the module in the third direction.

[0022] According to the energy storage device described in (7) above of the present invention, the force when the fixing part is pulled in the third direction can be transmitted via the connection part to a wide area of ​​the part of the side member facing the second surface of the energy storage element, and the holding force of the side member acting along the first direction is equalized in the third direction.

[0023] (8) The energy storage device according to any one of (1) to (7) above, comprising: a first end member which is the end member disposed opposite to one end face of the module in the third direction; a second end member which is the end member disposed opposite to the other end face of the module in the third direction; and a connecting member which fastens the central portion of the first end member in the first direction and the central portion of the second end member in the second direction.

[0024] According to the energy storage device described in (8) above of the present invention, the module is prevented from expanding in the third direction at the center in the first direction by the connecting member. As a result, the module expands in the third direction at the end position in the first direction. Consequently, as the module expands, the fixing portion is moved toward the center of the energy storage element in the first direction, and the holding force toward the center in the first direction can be further improved. Thus, according to the energy storage device described in (8) above, it is possible to further improve the holding rigidity of the stacked plurality of energy storage elements.

[0025] The following description of an energy storage device according to an embodiment (including its modifications) of the present invention will be given with reference to the drawings. The embodiments described below are all general or specific examples. The numerical values, shapes, materials, components, arrangement and connection configurations of components, manufacturing processes, and the order of manufacturing processes shown in the following embodiments are examples and are not intended to limit the present invention. Dimensions and other specifications are not strictly illustrated in each figure. In each figure, the same or similar components are denoted by the same reference numerals.

[0026] In the following description and drawings, the direction along the long side of the rectangular shape of the flattened energy storage element when viewed from the thickness direction (longitudinal direction) is defined as the X-axis direction (first direction). The X-axis direction may also be referred to as the left-right direction. The thickness direction of the energy storage element and the stacking direction of the multiple energy storage elements in the energy storage unit are defined as the Y-axis direction (third direction). The Y-axis direction may also be referred to as the front-back direction. The direction along the short side of the rectangular shape of the energy storage element (short side direction) is defined as the Z-axis direction (second direction). The Z-axis direction may also be referred to as the up-down direction. These X-axis, Y-axis, and Z-axis directions are mutually orthogonal directions. Depending on the usage, the Z-axis direction may not be the up-down direction, but for the sake of explanation below, the Z-axis direction will be described as the up-down direction.

[0027] In the following descriptions and diagrams, the arrow on the X-axis indicates leftward, and the opposite direction indicates rightward. The term "X-axis direction" simply refers to both left and right. The arrow on the Y-axis indicates forward, and the opposite direction indicates backward. The term "Y-axis direction" simply refers to both forward and backward. The arrow on the Z-axis indicates upward, and the opposite direction indicates downward. The term "Z-axis direction" simply refers to both up and down.

[0028] Expressions indicating relative directions or orientations, such as parallel and orthogonal, include cases where the directions or orientations are not strictly accurate. For example, two directions being parallel does not only mean that the two directions are perfectly parallel, but also that they are substantially parallel, i.e., they may have a difference of a few percent. In the following explanation, "insulation" refers to "electrical insulation."

[0029] <Energy Storage Device 1> First, the configuration of the energy storage device 1 in this embodiment will be described. Figure 1 is an exploded perspective view showing the schematic configuration of the energy storage device 1 according to this embodiment. Figure 2 is a perspective view of the energy storage unit 10 of the energy storage device 1. Figure 3 is a front view of the energy storage unit 10, Figure 4 is a top view of the energy storage unit 10, Figure 5 is a bottom view of the energy storage unit 10, Figure 6 is a left side view of the energy storage unit 10, Figure 7 is a right side view of the energy storage unit 10, and Figure 8 is a rear view of the energy storage unit 10.

[0030] The energy storage device 1 is a device that can charge electricity from an external source and discharge electricity to an external source. 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 the engine of mobile vehicles such as automobiles, motorcycles, watercraft, ships, snowmobiles, agricultural machinery, construction machinery, or railway vehicles for electric railways.

[0031] 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 the above-mentioned 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.

[0032] The energy storage device 1 comprises an energy storage unit 10 and a unit case 12 that houses the energy storage unit 10. The energy storage device 1 is equipped with external terminals 201 (positive external terminal and negative external terminal) for electrical connection to external devices. The energy storage device 1 may also be equipped with a circuit board and electrical equipment such as relays for monitoring or controlling the charging and discharging states of the energy storage unit 10.

[0033] The energy storage unit 10 is a battery module (battery pack) having a plurality of energy storage elements 100. The energy storage unit 10 has a roughly rectangular parallelepiped shape that is long in the Y-axis direction by stacking the plurality of energy storage elements 100 in the Y-axis direction (front-to-back direction). The energy storage unit 10 is equipped with busbars 300, etc., that connect the plurality of energy storage elements 100 in series or in parallel. The busbars 300, etc., may connect all of the energy storage elements 100 in series, or any of the energy storage elements 100 may be connected in parallel and then connected in series, or all of the energy storage elements 100 may be connected in parallel.

[0034] In this embodiment, as shown in Figure 1, multiple busbars 300 are provided to connect adjacent energy storage elements 100 in the Y-axis direction. The multiple energy storage elements 100 are connected in series using the busbars 300 and are connected to the external terminal 201.

[0035] The energy storage element 100 is a secondary battery (single cell) that can charge and discharge electricity, and more specifically, a non-aqueous electrolyte secondary battery such as a lithium-ion secondary battery. The energy storage element 100 has a flattened rectangular parallelepiped shape (square, prism) in the Y-axis direction. In this embodiment, multiple energy storage elements 100 are arranged in line in the Y-axis direction, but the number of energy storage elements 100 is not particularly limited.

[0036] The energy storage element 100 is not limited to a non-aqueous electrolyte secondary battery, but may be a secondary battery other than a non-aqueous electrolyte secondary battery, or a capacitor. The energy storage element 100 may not be a secondary battery, but a primary battery that allows the user to use the stored electricity without charging. The energy storage element 100 may be a battery using a solid electrolyte. The energy storage element 100 may be a pouch-type battery.

[0037] The unit case 12, which houses the energy storage unit 10, is a roughly rectangular parallelepiped (box-shaped) container that constitutes the outer casing (shell) of the energy storage device 1. The unit case 12 is positioned outside the energy storage unit 10, fixing the energy storage unit 10 in a predetermined position and protecting it from impacts and the like.

[0038] The unit case 12 is a metal case formed from a metal component such as aluminum, aluminum alloy, stainless steel, iron, or plated steel sheet. For example, the unit case 12 is formed from aluminum die casting. The unit case 12 may also be formed from a high-strength resin material (insulating material).

[0039] <Energy Storage Unit 10> As shown in Figures 1 to 8, the energy storage element 100 has a flattened shape with its thickness direction oriented in the front-to-back direction. When viewed from the thickness direction, the energy storage element 100 has a rectangular shape that is long in the left-to-right direction. The energy storage element 100 constitutes a rectangular corner cell when viewed from the thickness direction. The positive and negative terminals 106 of the energy storage element 100 are distributed and arranged on the left and right side portions (short side portions 102). The energy storage element 100 is not limited to a configuration in which the terminals 106 are arranged on the short side portions 102. The terminals 106 may also be arranged on the upper and lower side portions (long side portions 101). A gas discharge valve 107 is arranged on at least one of the left and right side portions. The description of the internal structure of the energy storage element 100 is omitted.

[0040] Each energy storage element 100 has a long side portion 101 along the long side of the rectangle and a short side portion 102 along the short side of the rectangle. Hereinafter, the virtual surface that includes the upper long side portion 101 of each energy storage element 100 and faces upward will be referred to as the upper surface 101a (second surface) of the energy storage element 100. The virtual surface that includes the lower long side portion 101 of each energy storage element 100 and faces downward will be referred to as the lower surface 101b (second surface) of the energy storage element 100. The upper surface 101a and the lower surface 101b are surfaces perpendicular to the Z-axis direction.

[0041] Furthermore, the imaginary surface facing left, including the left short side portion 102 of each energy storage element 100, is defined as the left side surface 102a (first surface) of the energy storage element 100. The imaginary surface facing right, including the right short side portion 102 of each energy storage element 100, is defined as the right side surface 102b (first surface) of the energy storage element 100. The left side surface 102a and the right side surface 102b are surfaces perpendicular to the X-axis direction.

[0042] The energy storage element 100 is arranged with its longitudinal direction (long side) aligned with the longer side 101 of the rectangular shape (longitudinal direction) in the left-right direction (X-axis direction), its short side 102 aligned with the shorter side (short side direction) in the up-down direction (Z-axis direction), and its thickness direction aligned with the front-back direction (Y-axis direction).

[0043] A module body 110 (module) is formed by stacking a plurality of power storage elements 100 so as to overlap in the thickness direction (Y-axis direction). Hereinafter, the Y-axis direction may be referred to as the stacking direction of the module body 110. A pair of end plates 115 (end members) are disposed on the outermost surfaces 111 on both sides in the stacking direction of the module body 110.

[0044] For example, the end plate 115 is not limited to an actual plate material, and may be a virtual plate material in which a framework formed by a plurality of beams is arranged in a plate shape. For example, each end plate 115 may have a rectangular plate shape overlapping the power storage element 100 when viewed from the stacking direction. In the present embodiment, the end plate 115 includes a plate-shaped plate portion 130 and a frame-shaped frame portion 140. The plate portion 130 and the frame portion 140 are stacked in the Y-axis direction such that the frame portion 140 is located on the outer side (opposite to the module body 110) and the plate portion 130 is located on the inner side.

[0045] The end plate 115 has a flat shape with the thickness direction oriented in the front-rear direction. The end plate 115 has a rectangular shape elongated in the left-right direction when viewed from the thickness direction. The end plate 115 includes a long side portion 116 along the long side of the rectangular shape, and a short side portion 117 along the short side of the rectangular shape. Hereinafter, an imaginary surface facing upward including the upper long side portion 116 of each end plate 115 is defined as an upper surface 116a of the end plate 115. An imaginary surface facing downward including the lower long side portion 116 of each end plate 115 is defined as a lower surface 116b of the end plate 115.

[0046] Further, an imaginary surface facing left including the left short side portion 117 of each end plate 115 is defined as a left side surface 117a of the end plate 115. An imaginary surface facing right including the right short side portion 117 of each end plate 115 is defined as a right side surface 117b of the end plate 115.

[0047] A bind bar 120 (connection member) extends across between the central portions of rectangular long side portions 116 on the end plates 115 on both sides in the stacking direction. Both end portions 121 of the bind bar 120 in the length direction (stacking direction) are each fastened to the central portion of the long side portion 116 of the end plates 115 on both sides in the stacking direction.

[0048] An imaginary plane extending between the upper surfaces 116a of the end plates 115 on both sides in the stacking direction is defined as the upper surface 112a of the module body 110, and an imaginary plane extending between the lower surfaces 116b of the end plates 115 on both sides in the stacking direction is defined as the lower surface 112b of the module body 110.

[0049] On the upper surface 112a of the module body 110, the upper surfaces 101a of the plurality of power storage elements 100 are aligned. On the lower surface 112b of the module body 110, the lower surfaces 101b of the plurality of power storage elements 100 are aligned. The direction along the long side portion 101 of each power storage element 100 and the long side portion 116 of each end plate 115 is defined as the longitudinal direction of the power storage elements 100 and the end plates 115 (and thus the module body 110).

[0050] Among the directions along the upper surface 112a and the lower surface 112b of the module body 110, the stacking direction is defined as the front-rear direction (Y-axis direction), and the direction intersecting (perpendicular to) the stacking direction is defined as the left-right direction (X-axis direction). The direction intersecting (perpendicular to) the upper surface 112a and the lower surface 112b is defined as the up-down direction (Z-axis direction).

[0051] An imaginary plane extending between the left side surfaces 117a of the end plates 115 on both sides in the stacking direction is defined as the left side surface 113a of the module body 110, and an imaginary plane extending between the right side surfaces 117b of the end plates 115 on both sides in the stacking direction is defined as the right side surface 113b of the module body 110.

[0052] On the left side surface 113a of the module body 110, the left side surfaces 102a of the plurality of power storage elements 100 are aligned. On the right side surface 113b of the module body 110, the right side surfaces 102b of the plurality of power storage elements 100 are aligned. The direction along the short side portion 102 of each power storage element 100 and the short side portion 117 of each end plate 115 is defined as the widthwise direction of the power storage elements 100 and the end plates 115 (and thus the module body 110).

[0053] The arrangement of the module body 110 described above is just one example; for example, the module body 110 may be arranged with its longitudinal direction tilted or vertical instead of horizontal.

[0054] <Bind Bar 120> As shown in Figures 1 to 8, the upper long sides 116 and the lower long sides 116 of the end plates 115 on both sides in the stacking direction are connected by bind bars 120 that extend in the stacking direction. Each bind bar 120 is provided along the upper surface 112a or lower surface 112b of the module body 110. Each bind bar 120 is plate-shaped (strip-shaped) along the upper surface 112a or lower surface 112b of the module body 110.

[0055] Each bind bar 120 extends in the stacking direction, and its ends 121 on both sides in the longitudinal direction are fastened to end plates 115 on both sides in the stacking direction. The ends 121 on both sides of each bind bar 120 are fixed to the corresponding end plate 115 by fastening, for example, with bolts B1 along the stacking direction. The end plates 115 and the bind bars 120 may also be fastened together by welding, adhesive, or the like.

[0056] The upper and lower bind bars 120 are arranged symmetrically, for example, vertically. Each bind bar 120 is formed symmetrically, for example, in the length direction (stacking direction). Each of the front and rear ends 121 of the upper bind bar 120 has a first piece 121a that follows the upper surface 112a of the module body 110 and a second piece 121b that follows the outermost surface 111 of the end plate 115. Each of the ends 121 of the lower bind bar 120 has a first piece 121a that follows the lower surface 112b of the module body 110 and a second piece 121b that follows the outermost surface 111 of the end plate 115. The front and rear ends 121 of each bind bar 120 are bent into an L-shape when viewed from the left and right directions and are integrally formed.

[0057] <Side Plates 125> The energy storage unit 10 comprises a pair of left and right side plates 125 (side members) and a pair of front and rear end plates 115. The front and rear end plates 115 and the left and right side plates 125 are connected in a frame shape that surrounds the outer circumference of the module body 110 in a plan view. Multiple energy storage elements 100 in the module body 110 are constrained in a stacked state by the front and rear end plates 115 and the left and right side plates 125. The central part in the longitudinal direction of the module body 110 is constrained in a stacked state by the upper and lower bind bars 120.

[0058] The module body 110 is integrated by the front and rear end plates 115, the left and right side plates 125, and the upper and lower binding bars 120, making it easier to handle the energy storage unit 10 as a single unit. The front and rear end plates 115 and the left and right side plates 125 form the outer frame, making the energy storage unit 10 robust against inputs from both inside and outside.

[0059] The side plates 125 are provided on the left and right sides of the module body 110. The left side plate 125 and the right side plate 125 are formed in a symmetrical shape. Each side plate 125 includes a side wall portion 125a, an upper flange portion 125b, an upper corner portion 125c (bent portion), a lower flange portion 125d, a lower corner portion 125e, a first fixing portion 125f, a connecting portion 125g, a second fixing portion 125h, and a third fixing portion 125i.

[0060] The side wall portion 125a is a wall portion positioned opposite to the side of the energy storage element 100 perpendicular to the X-axis direction. The side wall portion 125a of the side plate 125 located on the left side of the module body 110 is positioned opposite to the left side surface 102a of the energy storage element 100. The side wall portion 125a of the side plate 125 located on the right side of the module body 110 is positioned opposite to the right side surface 102b of the energy storage element 100. The side wall portion 125a presses the energy storage element 100 from the outside in the X-axis direction.

[0061] The side wall portion 125a extends along the Y-axis direction, and its end portion 125j in the Y-axis direction is located further outward in the Y-axis direction than the external terminal 201. In other words, the front end portion 125j of the side wall portion 125a is located in front of the external terminal 201, which is located at the front. Also, the rear end portion 125j of the side wall portion 125a is located behind the external terminal 201, which is located at the rear.

[0062] Furthermore, the side wall portion 125a is provided with an opening 125k at a position facing the terminal 106 of the energy storage element 100. Multiple openings 125k are provided so as to be arranged in the Y-axis direction. Each opening 125k is provided penetrating the side wall portion 125a in the X-axis direction. In this embodiment, each opening 125k is formed to be sized to face two adjacent terminals 106 in the Y-axis direction. However, the size and shape of the openings 125k can be changed. Also, in the case of an energy storage element in which the terminals 106 are provided on the upper and lower side portions (long side portions 101), multiple openings 125k may be provided on the upper flange piece 125b or the lower flange piece 125d. A busbar 300 is joined to the terminal 106. Therefore, what is exposed at the opening 125k is the busbar 300. Because the portion of the energy storage element 100 facing the terminals is exposed by this opening 125k, welding work can be performed between the terminals 106 and the busbar 300.

[0063] Furthermore, a recess 125m extending linearly along the Y-axis is provided in the central part of the side wall portion 125a in the Z-axis direction. The recess 125m is formed to curve inward from the outside of the module body 110. The recess 125m provided in the side wall portion 125a of the side plate 125 located on the left side of the module body 110 is formed to curve inward from the left side to the right side. The recess 125m provided in the side wall portion 125a of the side plate 125 located on the right side of the module body 110 is formed to curve inward from the right side to the left side.

[0064] The recess 125m allows the side wall portion 125a to tilt relative to the recess 125m in the circumferential direction when viewed from the Y-axis direction, with the upper and lower parts of the side wall portion 125a tilting relative to the recess 125m. As a result, the side plate 125 can be deformed so that the upper flange piece 125b and the lower flange piece 125d move apart in the Z-axis direction. Therefore, the side plate 125 can be easily attached to the module body 110. Furthermore, the side plate 125 can flexibly follow the deformation of the module body 110 when the energy storage element 100 expands.

[0065] The upper flange piece 125b is the part that faces the upper surface 101a of the energy storage element 100. The upper flange piece 125b is connected to the upper end of the side wall 125a via the upper corner portion 125c. The upper flange piece 125b of the side plate 125 located on the left side of the module body 110 is formed to protrude to the right from the upper corner portion 125c when viewed from the Y-axis direction. The upper flange piece 125b of the side plate 125 located on the right side of the module body 110 is formed to protrude to the left from the upper corner portion 125c when viewed from the Y-axis direction. The upper flange piece 125b holds the energy storage element 100 in place from above.

[0066] The upper corner portion 125c is a bent section that connects the side wall portion 125a and the upper flange piece 125b. The upper corner portion 125c is provided with a plurality of through holes 125n. These through holes 125n are arranged in the Y-axis direction. The through holes 125n function as low-rigidity sections, making the section where the through holes 125n are provided less rigid compared to other sections. In other words, the upper corner portion 125c has lower rigidity in the section where the low-rigidity through holes 125n are formed compared to other sections. As a result of providing such through holes 125n, the upper corner portion 125c is more prone to bending than if the through holes 125n were not provided.

[0067] In this embodiment, since the central part of the end plate 115 in the X-axis direction is fixed by the bind bar 120, when the energy storage element 100 expands, both ends of the module body 110 in the X-axis direction bulge outward in the Y-axis direction. At this time, a force that causes it to curve acts on the upper corner portion 125c. Since the upper corner portion 125c is provided with multiple through holes 125n, it can deform flexibly when subjected to the above force.

[0068] The lower flange piece 125d is the portion facing the lower surface 101b of the energy storage element 100. The lower flange piece 125d is connected to the lower end of the side wall portion 125a via the lower corner portion 125e. The lower flange piece 125d of the side plate 125 located on the left side of the module body 110 is formed to protrude to the right from the lower corner portion 125e when viewed from the Y-axis direction. The lower flange piece 125d of the side plate 125 located on the right side of the module body 110 is formed to protrude to the left from the lower corner portion 125e when viewed from the Y-axis direction. The lower flange piece 125d holds the energy storage element 100 in place from below.

[0069] The lower corner portion 125e is a bent section that connects the side wall portion 125a and the lower flange piece 125d. A gas discharge opening 125p is provided in the lower corner portion 125e. Multiple gas discharge openings 125p are provided along the Y-axis. Furthermore, the gas discharge openings 125p are formed extending from the lower corner portion 125e to the lower part of the side wall portion 125a.

[0070] The first fixing portion 125f, the second fixing portion 125h, and the third fixing portion 125i are parts that are fixed to the end plate 115. The first fixing portion 125f, the second fixing portion 125h, and the third fixing portion 125i can be fixed to the end plate 115 by bolts (not shown).

[0071] The first fixing portion 125f is a fixing portion connected to the upper flange piece 125b via a connecting portion 125g. The first fixing portion 125f is provided at each end of the side plate 125 in the Y-axis direction. The first fixing portion 125f located on the front side is fixed to the front end plate 115. The first fixing portion 125f located on the rear side is fixed to the rear end plate 115.

[0072] The first fixing portion 125f is located on the central side of the energy storage element 100 in the X-axis direction, beyond the end of the upper flange piece 125b on the central side of the energy storage element 100. The first fixing portion 125f provided on the side plate 125 located on the left side of the module body 110 is located to the right of the left end of the upper flange piece 125b. The first fixing portion 125f provided on the side plate 125 located on the right side of the module body 110 is located to the left of the right end of the upper flange piece 125b. Because the first fixing portion 125f is located on the central side of the energy storage element 100 beyond the end of the upper flange piece 125b on the central side of the energy storage element 100, when the module body 110 expands in the Y-axis direction, a force acts on the side plate 125 that pulls it toward the module body 110. Therefore, it is possible to suppress the movement of the energy storage element 100 in the X-axis direction.

[0073] Furthermore, the first fixing portion 125f is located on the central side of the energy storage element 100, relative to the upper surface 101a of the energy storage element 100, in the Z-axis direction. In other words, the first fixing portion 125f is located below the upper surface 101a of the energy storage element 100 when viewed from the Y-axis direction. Because the first fixing portion 125f is located below the upper surface 101a of the energy storage element 100, the upper flange piece 125b can be pressed against the module body 110 from above.

[0074] The connecting portion 125g is the part that connects the first fixing portion 125f and the upper flange piece 125b. The connecting portion 125g extends outward in the X-axis direction as it moves from the first fixing portion 125f toward the center of the module body 110 in the Y-axis direction. Preferably, the Y-axis dimension of the connecting portion 125g is 20% or more of the Y-axis dimension of the module body 110. Also, the Y-axis dimension of the connection range between the connecting portion 125g and the upper flange piece 125b may also be 20% or more of the Y-axis dimension of the module body 110. For example, if the connection range between the connecting portion 125g and the upper flange piece 125b is larger than the X-axis dimension of the connecting portion 125g, the force when the first fixing portion 125f is pulled in the Y-axis direction can be transmitted over a wide area of ​​the upper flange piece 125b.

[0075] The second fixing portion 125h is provided at the Y-axis end of the lower flange piece 125d and is fixed to the end plate 115 from below. In the X-axis direction, the second fixing portion 125h is located further out from the energy storage element 100 than the first fixing portion 125f. The second fixing portion 125h provided on the side plate 125 located on the left side of the module body 110 is located to the left of the first fixing portion 125f provided on the same side plate 125. The second fixing portion 125h provided on the side plate 125 located on the right side of the module body 110 is located to the right of the first fixing portion 125f provided on the same side plate 125. This allows the second fixing portion 125h to be directly attached to the lower flange piece 125d, and allows a wider area of ​​the lower surface 112b of the module body 110 to be exposed than when a connecting portion is provided to connect the second fixing portion 125h and the lower flange piece 125d. Therefore, the cooling efficiency of the module body 110 can be improved.

[0076] The third fixing portion 125i is provided at the lower parts of both ends of the side wall portion 125a in the Y-axis direction and is fixed to the end plate 115 from the X-axis direction. The third fixing portion 125i provided on the side plate 125 located on the left side of the module body 110 is fixed to the end plate 115 from the left side. The third fixing portion 125i provided on the side plate 125 located on the right side of the module body 110 is fixed to the end plate 115 from the right side.

[0077] <End Plate 115> Each end plate 115 comprises a plate-shaped plate portion 130 and a frame-shaped frame portion 140, as described above. The plate portion 130 is located closer to the module body 110 than the frame portion 140. In the case of an end plate 115 located in front of the module body 110, the plate portion 130 is located behind the frame portion 140. In the case of an end plate 115 located behind the module body 110, the plate portion 130 is located in front of the frame portion 140.

[0078] The plate portion 130 is a plate-shaped part positioned opposite the end face of the module body 110 that is perpendicular to the Y-axis direction. The plate portion 130 is formed to cover the end face of the module body 110 that is perpendicular to the Y-axis direction when viewed from the Y-axis direction.

[0079] The frame portion 140 includes a bind bar fixing portion 141, a first fixing portion 142, a second fixing portion 143, a third fixing portion 144, a mounting portion 145, and a plurality of arm portions 146. The frame portion 140 is formed in a flat shape as a whole, with the bind bar fixing portion 141, the first fixing portion 142, the second fixing portion 143, the third fixing portion 144, the mounting portion 145, and the plurality of arm portions 146 being integrally connected.

[0080] The bind bar fixing section 141 is located in the center of the frame section 140 in the X-axis direction. The bind bar fixing section 141 is the part to which the bind bar 120 is fixed. The bind bar 120 located on the upper side of the module body 110 is fixed to the upper part of the bind bar fixing section 141 using bolts B1. The bind bar 120 located on the lower side of the module body 110 is fixed to the lower part of the bind bar fixing section 141 using bolts B1.

[0081] The first fixing portion 142 is a part that is fixed to the first fixing portion 125f of the side plate 125, and two are provided for each frame portion 140, sandwiching the bind bar fixing portion 141 in the X-axis direction. Each first fixing portion 142 is located below the first fixing portion 125f of the side plate 125. The first fixing portion 142 located to the left of the bind bar fixing portion 141 is fixed to the first fixing portion 125f of the side plate 125 located to the left of the module body 110. The first fixing portion 142 located to the right of the bind bar fixing portion 141 is fixed to the first fixing portion 125f of the side plate 125 located to the right of the module body 110.

[0082] The second fixing portion 143 is a part that is fixed to the second fixing portion 125h of the side plate 125, and two are provided for each frame portion 140, sandwiching the bind bar fixing portion 141 in the X-axis direction. Each second fixing portion 143 is located above the second fixing portion 125h of the side plate 125. The second fixing portion 143 located to the left of the bind bar fixing portion 141 is fixed to the second fixing portion 125h of the side plate 125 located to the left of the module body 110. The second fixing portion 143 located to the right of the bind bar fixing portion 141 is fixed to the second fixing portion 125h of the side plate 125 located to the right of the module body 110.

[0083] The third fixing portion 144 is a part that is fixed to the third fixing portion 125i of the side plate 125, and two are provided for each frame portion 140, sandwiching the bind bar fixing portion 141 in the X-axis direction. Each third fixing portion 144 is located to the side of the third fixing portion 125i of the side plate 125. The third fixing portion 144 located to the left of the bind bar fixing portion 141 is fixed to the third fixing portion 125i of the side plate 125 located to the left of the module body 110. The third fixing portion 144 located to the right of the bind bar fixing portion 141 is fixed to the third fixing portion 125i of the side plate 125 located to the right of the module body 110.

[0084] The mounting portion 145 is a part for fixing the end plate 115 to an external member (for example, the unit case 12). Two mounting portions 145 are provided for each frame portion 140, sandwiching the bind bar fixing portion 141 in the X-axis direction. The mounting portions 145 are located below the first fixing portion 142 and above the second fixing portion 143, and are located further outside the energy storage element 100 than the first fixing portion 142 in the X-axis direction. The mounting portion 145 located to the left of the bind bar fixing portion 141 is located to the left of the first fixing portion 142, which is located to the left of the bind bar fixing portion 141. The mounting portion 145 located to the right of the bind bar fixing portion 141 is located to the left of the first fixing portion 142, which is located to the right of the bind bar fixing portion 141.

[0085] The multiple arm portions 146 are parts that connect two of the bind bar fixing portion 141, the first fixing portion 142, the second fixing portion 143, the third fixing portion 144, and the mounting portion 145. In this embodiment, the arm portions 146 include an arm portion 146 that connects the left first fixing portion 142 and the left mounting portion 145, an arm portion 146 that connects the upper part of the bind bar fixing portion 141 and the left mounting portion 145, and an arm portion 146 that connects the lower part of the bind bar fixing portion 141 and the left mounting portion 145. In addition, the arm portions 146 include an arm portion 146 that connects the right first fixing portion 142 and the right mounting portion 145, an arm portion 146 that connects the upper part of the bind bar fixing portion 141 and the right mounting portion 145, and an arm portion 146 that connects the lower part of the bind bar fixing portion 141 and the right mounting portion 145.

[0086] <External Terminal 201> The external terminal 201 is provided on the terminal block 200. Each end plate 115 is provided with a notch in which the terminal block 200 is housed. The terminal block 200 is positioned in the notch of each end plate 115. The terminal block 200 comprises the external terminal 201 and a base portion 202. The external terminal 201 is a total terminal connected to the terminals 106 of the multiple energy storage elements 100 via the bus bar 300. The base portion 202 supports the external terminal 201.

[0087] The external terminals 201 are located on the front and rear sides of the module body 110. One of these external terminals 201 is a positive external terminal electrically connected to the positive terminal 106 of the energy storage element 100. The other external terminal 201 is a negative external terminal electrically connected to the negative terminal 106 of the energy storage element 100.

[0088] The energy storage device 1 of this embodiment, as described above, comprises a module body 110, a side plate 125, and an end plate 115. The module body 110 has multiple energy storage elements 100 stacked in the Y-axis direction, which is perpendicular to the X-axis direction and the Z-axis direction. The energy storage elements 100 are rectangular parallelepipeds in which the dimension in the X-axis direction is larger than the dimension in the Z-axis direction, which is perpendicular to the X-axis direction. The side plate 125 is positioned opposite the left side surface 113a (or right side surface 113b) of the energy storage element 100 perpendicular to the X-axis direction. The end plate 115 is positioned opposite the end face of the module body 110 in the Y-axis direction. The side plate 125 is also formed by bending so as to straddle the left side surface 113a (or right side surface 113b) of each energy storage element 100 and the upper surface 112a of the energy storage element 100 perpendicular to the Z-axis direction. The side plate 125 includes a first fixing portion 125f. The first fixing portion 125f is connected to the upper flange piece 125b, which is the portion of the side plate 125 that faces the upper surface 112a. Furthermore, in the X-axis direction, the first fixing portion 125f is located closer to the center of the energy storage element 100 than the end portion of the energy storage element 100 that faces the upper surface 112a.

[0089] In this embodiment of the energy storage device 1, the side plate 125 has an upper flange piece 125b that faces the upper surface 112a of the energy storage element 100. The first fixing portion 125f is located closer to the center of the energy storage element 100 in the X-axis direction than the end of the upper flange piece 125b that faces the center of the energy storage element 100. When each energy storage element 100 expands, the module body 110 expands in the Y-axis direction. At this time, since the first fixing portion 125f is located on the side of the center of the energy storage element 100 in the X-axis direction, when the first fixing portion 125f is pulled in the Y-axis direction by the expansion of the module body 110 in the Y-axis direction, a holding force acts on the side plate 125 toward the center in the X-axis direction. For this reason, the energy storage device 1 of this embodiment makes it possible to improve the holding rigidity of the stacked multiple energy storage elements 100.

[0090] In the energy storage device 1 of this embodiment, the first fixed portion 125f is located on the central side of the energy storage element 100, relative to the upper surface 112a of the energy storage element 100, in the Z-axis direction.

[0091] In this embodiment of the energy storage device 1, since the first fixing portion 125f is located on the central side of the energy storage element 100 rather than the upper surface 112a of the energy storage element 100, the upper flange piece 125b is pressed against the upper surface 112a of the energy storage element 100 when the first fixing portion 125f is fixed to the end plate 115. Therefore, in this embodiment of the energy storage device 1, the side plate 125 can press against the upper surface 112a in addition to the left side surface 113a (or right side surface 113b) of the energy storage element 100, making it possible to further improve the holding rigidity of the stacked multiple energy storage elements 100.

[0092] In the energy storage device 1 of this embodiment, the upper corner portion 125c of the side plate 125 is provided with a low-rigidity portion (through hole 125n) that is less rigid compared to other parts of the upper corner portion 125c.

[0093] In this embodiment of the energy storage device 1, the rigidity of the upper corner portion 125c of the side plate 125 is reduced by the low-rigidity portion (through hole 125n) compared to the case where the low-rigidity portion is not provided. The upper corner portion 125c of the side plate 125 has higher rigidity than the side wall portion 125a and the upper flange piece 125b. By reducing the rigidity of the upper corner portion 125c in this way, when the energy storage element 100 expands, the shape of the side plate 125 can flexibly follow the shape change of the module body 110. Therefore, in this embodiment of the energy storage device 1, the holding force of the side plate 125 can be maintained even when the energy storage element 100 expands.

[0094] Figure 9 is a schematic cross-sectional view of the upper corner portion 125c. As shown in this figure, in the energy storage device 1 of this embodiment, the low-rigidity portion is a hole (through hole 125n) that penetrates the side plate 125, and multiple such holes are arranged along the Y-axis direction.

[0095] Figure 10 is a schematic cross-sectional view of the upper corner portion 125c in a modified example of the energy storage device 1 of this embodiment. As shown in this figure, the low-rigidity portion may be a recess 125q that is recessed from the surface of the side plate 125 toward the energy storage element 100. Multiple recesses 125q may be arranged along the Y-axis direction.

[0096] As in the energy storage device 1 of this embodiment, when a low-rigidity portion is formed by a through hole 125n, it is possible to suppress the temperature rise of the energy storage element 100 more effectively than when a low-rigidity portion consisting of a recess 125q is formed.

[0097] When a low-rigidity portion is formed by a recess 125q, as in the modified example of the energy storage device 1 of this embodiment, the area in which the energy storage element 100 is exposed can be reduced compared to when the low-rigidity portion is formed by a through hole 125n, and the protective area of ​​the energy storage element 100 can be increased.

[0098] In the energy storage device 1 of this embodiment, the energy storage element 100 has a terminal 106 on its upper surface 112a. The side plate 125 has an opening 125k at a position opposite to the terminal 106.

[0099] In this embodiment of the energy storage device 1, the portion of the energy storage element 100 facing the terminal 106 is exposed at the opening 125k of the side plate 125. Therefore, for example, welding work between the terminal 106 and the busbar 300 can be performed through the opening 125k.

[0100] In the energy storage device 1 of this embodiment, the side plate 125 has a connecting portion 125g that connects the portion facing the upper surface 112a to the first fixing portion 125f. The dimension of the connecting portion 125g in the Y-axis direction is preferably 20% or more of the dimension of the module body 110 in the Y-axis direction.

[0101] According to this embodiment of the energy storage device 1, the force when the first fixing part 125f is pulled in the Y-axis direction can be transmitted via the connecting part 125g to a wide area of ​​the part of the side plate 125 facing the upper surface 112a of the energy storage element 100. Therefore, with this energy storage device 1, the holding force of the side plate 125 acting along the X-axis direction is equalized in the Y-axis direction.

[0102] The energy storage device 1 of this embodiment includes a first end plate 115 which is an end plate 115 positioned opposite one end face of the module body 110 in the Y-axis direction, and a second end plate 115 which is an end plate 115 which is positioned opposite the other end face of the module body 110 in the Y-axis direction. The energy storage device 1 of this embodiment also includes a bind bar 120 which fastens the central portion of the first end plate 115 in the X-axis direction and the central portion of the second end plate 115 in the Z-axis direction.

[0103] In this embodiment of the energy storage device 1, the binding bar 120 restricts the module body 110 from expanding in the Y-axis direction at its center in the X-axis direction. As a result, the module body 110 expands in the Y-axis direction at its end position in the X-axis direction. Consequently, the expansion of the module body 110 causes the first fixing portion 125f to move toward the center of the energy storage element 100 in the X-axis direction, thereby further improving the holding force toward the center in the X-axis direction. Therefore, in this embodiment of the energy storage device 1, it is possible to further improve the holding rigidity of the stacked energy storage elements 100.

[0104] 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 invention. Forms constructed by arbitrarily combining the components of the above embodiments and their modifications are also included within the scope of the present invention.

[0105] For example, the above embodiment described a configuration comprising two side plates 125. However, the present invention is not limited thereto, and for example, a configuration comprising one side plate 125, with the other being supported by a module case or the like, can also be adopted.

[0106] Furthermore, similar to the positional relationship between the first fixing portion 125f and the upper flange piece 125b, a configuration may be adopted in which the second fixing portion 125h is positioned closer to the center of the energy storage element 100 in the X-axis direction than the end of the lower flange piece 125d that is closer to the center of the energy storage element 100.

[0107] This invention can be applied to energy storage devices that stack multiple energy storage elements, such as lithium-ion secondary batteries.

[0108] 1...Energy storage device 100...Energy storage element 101...Long side 101a...Top surface 101b...Bottom surface 102...Short side 102a...Left side 102b...Right side 106...Terminal 107...Gas discharge valve 110...Module body (module) 111...Outermost surface 112a...Top surface (second surface) 112b...Bottom surface (second surface) 113a...Left side surface (first surface) 113b...Right side surface (first surface) 115...End plate (end member) 120...Bind bar 125...Side plate (side member) 125a...Side wall 125b...Upper flange piece 125c...Upper corner piece (bent part) 125d...Lower flange piece 125e...Lower corner piece 125f...First fixing part (fixing part) 125g...Connection part 125h...Second fixing part 125i...Third fixing part 125j...End part 125k...Opening 125m...Recess 125n...Through hole (low rigidity part) 125p...Gas discharge opening 125q...Recess 130...Plate part 140...Frame part 141...Bind bar fixing part 142...First fixing part 143...Second fixing part 144...Third fixing part 145...Mounting part 146...Arm part 200...Terminal block 201...External terminal 202...Base part 300...Bus bar

Claims

A module in which multiple rectangular parallelepiped energy storage elements, the dimensions of which are in the first direction are larger than the dimensions of which are in the second direction perpendicular to the first direction, are stacked in a third direction perpendicular to the first and second directions, A side member is positioned opposite the first surface of the energy storage element, which is perpendicular to the first direction, An end member positioned opposite the end face of the module in the third direction, Equipped with, The side member is formed by bending so as to span the first surface of each energy storage element and the second surface of the energy storage element that is perpendicular to the second direction, The fixing portion, which is connected to the portion of the side member facing the second surface and fixed to the end member, is located in the first direction, closer to the center of the energy storage element than the end of the portion facing the second surface that is closer to the center of the energy storage element. Energy storage device. 　 The fixing portion is located in the second direction, on the central side of the energy storage element, relative to the second surface of the energy storage element. The energy storage device according to claim 1. 　 The bent portion of the side member is provided with a low-rigidity section that has lower rigidity compared to other parts of the bent portion. The energy storage device according to claim 1 or 2. 　 The low-rigidity portion is a hole that penetrates the side member, and is arranged in multiple locations along the third direction. The energy storage device according to claim 3. 　 The low-rigidity portion is a recess that extends from the surface of the side member toward the energy storage element, and a plurality of these recesses are arranged along the third direction. The energy storage device according to claim 3. 　 The aforementioned energy storage element is provided with terminals, The side member has an opening at a position facing the terminal. The energy storage device according to claim 1 or 2. 　 The side member has a connecting portion that connects the portion facing the second surface with the fixing portion, The dimension of the connection portion in the third direction is 20% or more of the dimension of the module in the third direction. The energy storage device according to claim 1 or 2. 　 The first end member is the end member that is positioned opposite one of the end faces of the module in the third direction, A second end member, which is the end member, is positioned opposite the other end face of the module in the third direction, A connecting member that fastens the central portion of the first end member in the first direction and the central portion of the second end member in the second direction, Equipped with, The energy storage device according to claim 1 or 2.

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