Energy storage device

Abstract

To provide a power storage device which can suppress a variation in performance degradation of power storage elements.SOLUTION: A power storage device comprises: a laminate including a plurality of power storage elements lined up in a prescribed direction and a plurality of adjacent members disposed between the power storage elements; and a holding part for holding the laminate. Each of the plurality of adjacent members extends from an edge of one of the power storage elements to an edge of the other of the power storage elements at least in a direction orthogonal to the prescribed direction between the power storage elements. The bending strength of the adjacent member located in a central part of the laminate in the prescribed direction is greater than the bending strength of the adjacent member closest to an end of the laminate.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a power storage device in which a plurality of power storage elements are restrained by a holding member.

Background Art

[0002] Conventionally, a battery pack in which a plurality of battery cells are restrained in the arrangement direction has been known (see Patent Document 1). This battery pack includes a plurality of battery cells arranged in a row in one direction, a pair of end plates that sandwich the plurality of battery cells in a row from both ends in the arrangement direction of the plurality of battery cells, and a pair of binding bars that sandwich the plurality of battery cells from a direction perpendicular to the arrangement direction and fasten the pair of end plates at both ends in the arrangement direction. In the battery pack, the plurality of battery cells arranged in a row are tightly fastened in the arrangement direction by the pair of end plates and the pair of binding bars.

[0003] Thus, since the plurality of battery cells arranged in a row are tightly fastened in the arrangement direction by the pair of end plates and the pair of binding bars, in this battery pack, even if each battery cell expands due to aging or the like, the dimension in the arrangement direction of the battery pack does not change. Therefore, the expansion of each battery cell accumulates toward the center in the arrangement direction, and the force (pressure) toward the center applied from the adjacent battery cells to the battery cells closer to the center side becomes larger. As a result, the deterioration of the battery performance of the battery cells closer to the center side is greater. That is, there is a variation in the performance deterioration of each battery cell.

[0004] Since the performance of a battery pack including a plurality of battery cells is dominated by the performance of the most deteriorated battery cell, as described above, when there is a variation in the performance deterioration of each battery cell in the battery pack, that is, when the performance deterioration of some battery cells is large, the performance deterioration of the battery pack will progress rapidly.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] Therefore, the objective of this embodiment is to provide an energy storage device in which a plurality of energy storage elements arranged in a predetermined direction are held by a holding part, and which can suppress variations in the performance degradation of each energy storage element. [Means for solving the problem]

[0007] The energy storage device of this embodiment is A laminate including a plurality of energy storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between each energy storage element, It comprises a holding part for holding the laminate, Each of the plurality of adjacent members extends between the energy storage elements from one edge to the other edge of the energy storage element in a direction perpendicular to the predetermined direction. In the predetermined direction, the bending strength of the adjacent member located in the center of the laminate is greater than the bending strength of the adjacent member closest to the end of the laminate.

[0008] With this configuration, even when the expansion of the laminate in the X-axis direction is restricted by being held by the holding part, the bending strength of the adjacent member located in the center of the laminate in a predetermined direction is greater than the bending strength of the adjacent member closest to the end. Therefore, the expansion of each energy storage element located closer to the end of the laminate than the adjacent member located in the center is less likely to be transmitted to the energy storage element located closer to the center of the laminate than the adjacent member located in the center. As a result, performance degradation caused by the expansion of each energy storage element is suppressed in the energy storage element located closer to the center, and consequently, variations in the performance degradation of each energy storage element are suppressed.

[0009] Furthermore, the energy storage device of this embodiment is A laminate including a plurality of energy storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between each energy storage element, It comprises a holding part for holding the laminate, Each of the plurality of adjacent members extends between the energy storage elements from one edge to the other edge of the energy storage element in a direction perpendicular to the predetermined direction. The bending strength of a first adjacent member, which is a predetermined adjacent member in the laminate, is greater than the bending strength of a second adjacent member, which is located closer to the end in the predetermined direction than the first adjacent member in the laminate.

[0010] With this configuration, even when the elongation of the laminate in the X-axis direction is restricted by being held by the holding part, the bending strength of the first adjacent member is greater than the bending strength of the second adjacent member which is positioned closer to the edge of the laminate in a predetermined direction than the first adjacent member. As a result, the expansion of each energy storage element positioned closer to the edge of the laminate than the first adjacent member is less likely to be transmitted to the energy storage elements positioned closer to the center of the laminate than the first adjacent member. This suppresses performance degradation caused by the expansion of each energy storage element in the energy storage elements positioned closer to the center, and consequently reduces variations in the performance degradation of each energy storage element.

[0011] In the aforementioned energy storage device, In the laminate, the bending strength of one of two adjacent members, the adjacent member closer to the center of the laminate in the predetermined direction, may be greater than the bending strength of the adjacent member closer to the edge of the laminate.

[0012] With this configuration, the expansion of each energy storage element located closer to the edge of the laminate than to the adjacent member closer to the center is less likely to be transmitted to the energy storage element located closer to the center of the laminate than to the adjacent member closer to the center, thereby suppressing variations in the performance degradation of each energy storage element.

[0013] Furthermore, in the aforementioned energy storage device, In the laminate, adjacent members closer to the center in the predetermined direction may have greater bending strength.

[0014] According to such a configuration, the expansion of each power storage element is difficult to be transmitted to the power storage element closer to the center of the laminate in the predetermined direction, thereby suppressing variations in the performance degradation of each power storage element.

[0015] Further, the power storage device of the present embodiment includes a laminate including a plurality of power storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the respective power storage elements, and a holding portion that holds the laminate. Each of the plurality of adjacent members extends from one edge to the other edge of the power storage element at least in a direction orthogonal to the predetermined direction between the adjacent power storage elements. In the laminate, the bending strength of each adjacent member increases in order from the adjacent member closest to the end in the predetermined direction toward the center in the predetermined direction or the adjacent member closest to the center.

[0016] Also according to such a configuration, the expansion of each power storage element is difficult to be transmitted to the power storage element closer to the center of the laminate in the predetermined direction, thereby suppressing variations in the performance degradation of each power storage element.

Advantages of the Invention

[0017] As described above, according to the present embodiment, there is provided a power storage device in which a plurality of power storage elements arranged in a predetermined direction are held by a holding portion, and variations in the performance degradation of each power storage element can be suppressed.

Brief Description of the Drawings

[0018] [Figure 1] FIG. 1 is a perspective view of the power storage device according to the present embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the power storage device with a part of its configuration omitted. [Figure 3] FIG. 3 is a diagram showing the bending strength of the adjacent members at each position in the stacking direction of the power storage device. [Figure 4] FIG. 4 is a schematic diagram for explaining the difference in the bending strength of the adjacent members depending on the position in the stacking direction of the power storage device. [Figure 5] FIG. 5 is a diagram showing the bending strength of adjacent members at each position in the stacking direction of the power storage device according to another embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining a method of measuring the bending strength. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 to 4. Note that the names of the components (each component element) in this embodiment are those in this embodiment, and may be different from the names of the components (each component element) in the background art.

[0020] As shown in FIGS. 1 and 2, the power storage device includes a laminate L including a plurality of power storage elements 10, and a holding member (holding portion) 4 that holds the laminate L. Further, the power storage device 1 includes at least one insulator 6 disposed between the laminate L and the holding member 4, and a plurality of bus bars 8 that connect different power storage elements 10 in a conductive manner.

[0021] Specifically, the laminate L includes a plurality of power storage elements 10 and a plurality of adjacent members 2. In this laminate L, the power storage elements 10 and the adjacent members 2 are alternately arranged in a predetermined direction.

[0022] Each of the plurality of power storage elements 10 is a primary battery, a secondary battery, a capacitor, or the like. The power storage element 10 in this embodiment is a rechargeable non-aqueous electrolyte secondary battery. More specifically, the power storage element 10 is a lithium-ion secondary battery that utilizes electron transfer generated by the transfer of lithium ions.

[0023] Specifically, each power storage element 10 includes an electrode body, a case 13 that houses the electrode body together with an electrolytic solution, an external terminal 14 at least a part of which is exposed outside the case 13, and a current collector that connects the electrode body and the external terminal 14.

[0024] In the electrode body, positive and negative electrodes are stacked alternately with a separator in between. In this electrode body, lithium ions move between the positive and negative electrodes, causing the energy storage element 10 to charge and discharge.

[0025] Case 13 comprises a case body 131 having an opening and a plate-shaped cover plate 132 that closes (closes) the opening of the case body 131. In this embodiment, the case body 131 is a bottomed rectangular tube, and the case 13 is a rectangular parallelepiped (hexagonal) shape. In this embodiment, the case 13 is a flat rectangular parallelepiped shape, and the multiple energy storage elements 10 are arranged in the X-axis direction in the laminate L with the wide surfaces (walls) of the case 13 (case body 131) facing each other via adjacent members 2.

[0026] In the following explanation, the direction in which the multiple energy storage elements 10 are aligned (a predetermined direction) is defined as the X-axis of the Cartesian coordinate system, the direction in which the pair of narrow surfaces (walls) of the case 13 face each other is defined as the Y-axis of the Cartesian coordinate system, and the direction of the normal to the cover plate 132 is defined as the Z-axis of the Cartesian coordinate system.

[0027] Each of the multiple adjacent members 2 is insulating and is positioned between energy storage elements 10 aligned in the X-axis direction, or between an energy storage element 10 and a member aligned with respect to the energy storage element 10 in the X-axis direction (in this embodiment, a part of the holding member 4). Each of the multiple adjacent members 2 in this embodiment is formed of resin.

[0028] Furthermore, each of the multiple adjacent members 2 forms a flow path R through which a temperature-regulating fluid (a cooling fluid such as air in this embodiment) can flow between it and the adjacent energy storage element 10. These multiple adjacent members 2 include multiple types of adjacent members, and the multiple adjacent members 2 in this embodiment include intermediate adjacent members (adjacent members) 21 arranged between the energy storage elements 10, and end adjacent members 22 that are adjacent to the energy storage element 10 on the outside of the energy storage element 10 at the outermost end in the X-axis direction. That is, the energy storage device 1 comprises intermediate adjacent members 21 and end adjacent members 22 as adjacent members 2. The energy storage device 1 in this embodiment comprises multiple intermediate adjacent members 21 and two (a pair) of end adjacent members 22. Each of these multiple intermediate adjacent members 21 is arranged between each energy storage element 10.

[0029] Each of the multiple intermediate adjacent members (adjacent members) 21 has a first main body portion 211 that extends in a direction perpendicular to the X-axis direction between adjacent energy storage elements 10 in the X-axis direction, and at least one first restricting portion 215 that restricts the movement of the energy storage element 10 adjacent to the first main body portion 211 relative to the first main body portion 211.

[0030] The first main body portion 211 is a part that faces the wide surface of the case 13 of the energy storage element 10 and abuts against the wide surface. This first main body portion 211 extends from one edge to the other edge of the energy storage element 10 in a direction perpendicular to the X-axis direction with respect to the adjacent energy storage element 10. More specifically, the first main body portion 211 extends from one edge to the other edge of two opposing edges that straddle the center of the wide surface of the case 13 of the adjacent energy storage element 10. In this embodiment, the first main body portion 211 is the same size as or larger than the wide surface of the case 13 when viewed from the X-axis direction (its size includes the wide surface). As a result, the first main body portion 211 is sandwiched across the entire peripheral edge of the wide surface of the case 13 of the adjacent energy storage element 10.

[0031] The first main body 211, in cooperation with an adjacent energy storage element 10, forms a flow path R through which a temperature-regulating fluid can flow between it and the energy storage element 10. In this embodiment, the first main body 211 forms multiple flow paths R between it and an adjacent energy storage element 10. Specifically, the first main body 211 forms multiple flow paths R between it and an adjacent energy storage element 10 on one side in the X-axis direction, and also forms multiple flow paths R between it and an adjacent energy storage element 10 on the other side in the X-axis direction. When viewed from the X-axis direction, the first main body 211 is rectangular in shape with a size corresponding to the adjacent energy storage element 10, and the cross-section of the first main body 211 along the XZ plane (the plane including the X-axis and Z-axis directions) is rectangular corrugated.

[0032] The first restricting portion 215 extends in the X-axis direction from at least one corner of the rectangular first main body portion 211 and restricts the relative movement of the energy storage element 10 (specifically the case 13) adjacent to the first main body portion 211 in the YZ plane direction (a plane including the Y-axis direction and the Z-axis direction) by contacting the energy storage element 10 from the outside in the YZ plane direction. In this embodiment, the first restricting portion 215 extends from the first main body portion 211 to both sides in the X-axis direction.

[0033] Each of the two end adjacent members (adjacent members) 22 has a second main body portion 221 that extends in a direction perpendicular to the X-axis direction between adjacent energy storage elements 10 in the X-axis direction and the holding member 4 (more specifically, the terminal member 41), and at least one second restricting portion 225 that restricts the movement of the energy storage element 10 adjacent to the second main body portion 221 relative to the second main body portion 221.

[0034] The second main body portion 221 is the part that faces the wide surface of the case 13 of the energy storage element 10, with a portion of it in contact with it. This second main body portion 221 extends from one edge to the other edge of the energy storage element 10 in a direction at least perpendicular to the X-axis direction, relative to the adjacent energy storage element 10. More specifically, the second main body portion 221 extends from one edge to the other edge of two opposing edges that straddle the center of the wide surface of the case 13 of the adjacent energy storage element 10. In this embodiment, the second main body portion 221 is the same size as or larger than the wide surface of the case 13 when viewed from the X-axis direction (its size includes the wide surface). Also, when viewed from the X-axis direction, the terminal member 41 is the same size as or slightly larger than the energy storage element 10 (more specifically, the case 13). As a result, the second main body portion 221 is sandwiched between the adjacent terminal member 41 and the wide surface of the case 13 of the energy storage element 10 across the entire periphery.

[0035] Similar to the first main body 211 of the intermediate adjacent member 21, the second main body 221 also works in cooperation with the adjacent energy storage element 10 to form a flow path R through which a temperature-regulating fluid can flow between it and the energy storage element 10. In this embodiment, the second main body 221 forms multiple flow paths R between it and the adjacent energy storage element 10. This second main body 221 is a rectangular plate shape with a size corresponding to the adjacent energy storage element 10 when viewed from the X-axis direction, and the second main body 221 in this embodiment is a rectangular shape that is elongated in the Y-axis direction.

[0036] Specifically, the second main body portion 221 extends in a direction perpendicular to the X-axis direction at one end or the other end of the laminated body L in the X-axis direction and has two opposing surfaces 2211 that face adjacent energy storage elements 10 (the wide surface of the case 13) or terminal members 41, and a plurality of protrusions 2212 that project from the opposing surface 2211 on the energy storage element 10 side. Each of the plurality of protrusions 2212 extends in the Y-axis direction and is spaced apart in the Z-axis direction.

[0037] The second restricting portion 225 extends in the X-axis direction from at least one corner of the rectangular second main body portion 221 and restricts the relative movement of the energy storage element 10 (specifically the case 13) adjacent to the second main body portion 221 in the YZ-axis direction by contacting it from the outside in the YZ-axis direction. In this embodiment, the second restricting portion 225 extends from the second main body portion 221 toward one side in the X-axis direction (towards the energy storage element 10).

[0038] The multiple adjacent members 2 (intermediate adjacent members 21) configured as described above include adjacent members 2 with different bending strengths. Specifically, as shown in Figure 3, the intermediate adjacent members 21 closer to the center in the X-axis direction in the laminate L have greater bending strength. In this strength distribution graph, the bending strength does not change linearly from the ends in the direction of the arrangement of the energy storage elements 10 in the laminate L toward the center, but rather changes curvilinearly. The difference in bending strength of these multiple intermediate adjacent members 21 is caused by differences in the thickness (dimension in the X-axis direction) of the adjacent members 2, differences in material, differences in structure (for example, differences in the pitch of the rectangular waves in the rectangular wave cross-section), and combinations thereof. Here, the bending strength in this embodiment is measured as the force F when the adjacent member 2 bends when the center of the YZ plane (the center in the Y-axis direction and the center in the Z-axis direction) is pressed while both ends of the adjacent member 2 in the Y-direction are supported by fulcrums 9, as shown in Figure 6. Each fulcrum 9 supports the adjacent member 2 by its apex, which extends linearly in the Z-axis direction.

[0039] More specifically, among the multiple intermediate adjacent members 21, the intermediate adjacent member 21 located in the center of the laminate L in the X-axis direction has the greatest bending strength, while the intermediate adjacent member 21 located at the end in the X-axis direction (the position closest to the end of the laminate L in the X-axis direction) has the least bending strength. Note that the intermediate adjacent member 21 located in the center refers to the single intermediate adjacent member 21 in the center in the X-axis direction when the number of intermediate adjacent members 21 is odd, and refers to the two intermediate adjacent members 21 closest to the center in the X-axis direction when the number of intermediate adjacent members 21 is even.

[0040] Furthermore, in the laminate L, if the strength distribution of the bending strength of adjacent members 2 in the X-axis direction (the stacking direction of the energy storage elements 10) is as shown in Figure 3, then the bending strength of a predetermined adjacent member 2 in the laminate L, namely the first adjacent member (for example, adjacent member No. 7 in Figure 4) 2A, is greater than the bending strength of the second adjacent member (for example, adjacent member No. 3 in Figure 4) 2B, which is located closer to the end of the laminate L in the X-axis direction than the first adjacent member 2A. Also, in the laminate L, the bending strength of the adjacent member 2A closer to the center of the laminate L in the X-axis direction (for example, adjacent member No. 7 in Figure 4) 2A is greater than the bending strength of the adjacent member 2C closer to the end of the laminate L (for example, adjacent member No. 6 in Figure 4) 2C.

[0041] The holding member 4 has at least one holding portion (holding region) that surrounds the laminate L and holds the laminate L in a tightened state in the X-axis direction. The holding member 4 in this embodiment is composed of only one holding portion. This holding portion is the part that holds the laminate L while restricting its elongation in the X-axis direction. In the energy storage device 1 of this embodiment, one holding portion holds one laminate L; in other words, multiple energy storage elements 10 and multiple adjacent members 2 held by one holding portion constitute one laminate L.

[0042] The holding member 4 is made of a conductive material such as metal. Specifically, the holding member 4 has a pair of end members 41 arranged on both sides of the laminate L (a plurality of energy storage elements 10 arranged in the X-axis direction), a pair of connecting members 42 that connect the pair of end members 41, and a plurality of connecting members 43 that connect the end members 41 and the connecting members 42.

[0043] The pair of end members 41 are positioned on both sides of the laminate L in the X-axis direction. Specifically, each of the pair of end members 41 is positioned to sandwich an adjacent end member 22 between itself and the energy storage element 10 located at the X-axis end (outermost) of the laminate L. Each of these pair of end members 41 is a rectangular plate shape with a size corresponding to the energy storage element 10 when viewed from the X-axis direction, and the rigidity of each end member 41 is higher than that of each adjacent member 2. Specifically, each end member 41 is a rectangular shape that is elongated in the Y-axis direction and has a plurality of through holes 411 at both ends in the Y-axis direction that are spaced apart in the Z-axis direction.

[0044] Each of the pair of connecting members 42 is positioned on both sides of the laminate L in the Y-axis direction and extends along the laminate L in the X-axis direction. Each connecting member 42 has a pair of beam sections 421 that extend in the X-axis direction and are spaced apart in the Z-axis direction, a pair of end connecting sections 422 that connect the ends of the pair of beam sections 421, and an intermediate connecting section 425 that connects the pair of beam sections 421 at an intermediate position in the X-axis direction. In this embodiment, the connecting member 42 has a plurality of intermediate connecting sections 425.

[0045] Each end connecting portion 422 has a fixing piece 423 that extends along the outer surface of the end member 41 in the X-axis direction, and the fixing piece 423 has a through hole 424 that overlaps with the through hole 411 of the end member 41 when viewed from the X-axis direction.

[0046] Each of the multiple connecting members 43 connects the terminal member 41 and the connecting member 42 by inserting them through the through hole 411 of the terminal member 41 and the through hole 424 of the connecting member 42 (fixing piece 423). In this embodiment, each connecting member 43 is composed of a bolt 431 and a nut 432.

[0047] The insulator 6 has insulating properties. This insulator 6 is placed between the connecting member 42 and the laminate L (multiple energy storage elements 10). Specifically, the energy storage device 1 includes a pair of insulators 6, and each insulator 6 covers at least the region of the connecting member 42 that faces the laminate L. As a result, each insulator 6 insulates the connecting member 42 from the multiple energy storage elements 10 included in the laminate L.

[0048] Each of the multiple busbars 8 is a conductive plate-shaped member such as metal. Each busbar 8 connects the external terminals 14 of the energy storage elements 10 to each other. The multiple busbars 8 in this embodiment connect (connect) the multiple energy storage elements 10 included in the energy storage device 1 in series.

[0049] According to the energy storage device 1 described above, even when the expansion of the laminate L in the X-axis direction is restricted by the holding member 4, the bending strength of the intermediate adjacent member 21 located in the center of the laminate L in the X-axis direction is greater than the bending strength of the intermediate adjacent member 21 closest to the end. Therefore, the expansion of each energy storage element 10 located closer to the end of the laminate L than the intermediate adjacent member 21 located in the center of the laminate L is less likely to be transmitted to the energy storage element 10 located closer to the center of the laminate L (center in the X-axis direction) than the intermediate adjacent member 21 located in the center. Details are as follows.

[0050] When each energy storage element 10 swells due to aging or other factors, the dimensions of the laminated body L in the X-axis direction do not change due to the holding member 4 (holding part) (i.e., the distance between the pair of end members 41 does not change because they are connected by a metal connecting member 42). As a result, the swelling of each energy storage element 10 accumulates, and the energy storage element 10 closer to the center of the laminated body L in the X-axis direction tends to experience greater force (pinching force) from the energy storage elements on both sides in the X-axis direction. However, in the energy storage device 1 of this embodiment, the bending strength of the intermediate adjacent member 21 in the central part of the laminated body L in the X-axis direction is greater than the bending strength of the intermediate adjacent member 21 closest to the end (outer end) of the laminated body L in the X-axis direction. Therefore, the swelling of each energy storage element 10 closer to the end of the laminated body L in the X-axis direction than the intermediate adjacent member 21 in the central part is less likely to be transmitted to the energy storage element 10 located closer to the center of the laminated body L in the X-axis direction than the intermediate adjacent member 21 in the central part.

[0051] As a result, performance degradation caused by the force applied to the central energy storage element 10 due to the expansion of each energy storage element 10 due to degradation is suppressed, and consequently, variations in the performance degradation of each energy storage element 10 are suppressed.

[0052] In the energy storage device 1 of this embodiment, the bending strength of the intermediate adjacent member 21, which is closer to the center of the laminate L in the X-axis direction, is greater than that of the intermediate adjacent member 21 that is closer to the end of the laminate L. Therefore, the expansion of each energy storage element 10 located closer to the end of the laminate L than the intermediate adjacent member 21 that is closer to the center of the laminate L is less likely to be transmitted to the energy storage element 10 located closer to the center of the laminate than the intermediate adjacent member 21 that is closer to the center. As a result, variations in the performance degradation of each energy storage element 10 are suppressed.

[0053] Furthermore, in the energy storage device 1 of this embodiment, the bending strength is greater for intermediate adjacent members 21 closer to the center in the X-axis direction of the laminate L. Therefore, the expansion of each energy storage element 10 is less likely to be transmitted to the energy storage elements 10 closer to the center of the laminate L in the X-axis direction, thereby effectively suppressing variations in the performance degradation of each energy storage element 10.

[0054] Furthermore, if the bending strength of all intermediate adjacent members 21 is increased, the thickness of each intermediate adjacent member 21 increases, which increases the dimensions of the energy storage device 1 (laminated body L) in the X-axis direction. Also, if the intermediate adjacent members 21 are formed from materials that are more expensive than resin, such as insulating coated metal, the manufacturing cost of the energy storage device 1 increases. However, by increasing the strength of the intermediate adjacent members 21 near the center in the X-axis direction where the force applied to the energy storage elements 10 is large in the laminated body L, and decreasing the strength of the intermediate adjacent members 21 near the ends in the X-axis direction of the laminated body L, it is possible to suppress the increase in dimensions and manufacturing costs while also effectively suppressing variations in the performance degradation of each energy storage element 10.

[0055] It should be noted that the energy storage device of the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and a part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, a part of the configuration of one embodiment can be deleted.

[0056] In the energy storage device 1 of the above embodiment, the bending strength is greater for intermediate adjacent members 21 closer to the center in the X-axis direction in the laminated body L, but the configuration is not limited to this.

[0057] For example, the bending strength of a predetermined number of adjacent members 2 in the central part of the laminate L in the X-axis direction (for example, adjacent members No. 5 to No. 10 in Figure 4) may be greater than the bending strength of the remaining adjacent members 2 (on the end side) (for example, adjacent members No. 1 to No. 4 and No. 11 to No. 14 in Figure 4). In this case, the bending strength of each of the predetermined number of adjacent members 2 may be the same, or it may be greater for adjacent members 2 closer to the center.

[0058] Furthermore, in some of the multiple adjacent members 2 (for example, adjacent members No. 3 to No. 7 in Figure 4), the bending strength may be greater for adjacent members 2 closer to the center. With such a configuration, the force applied from at least one side in the X-axis direction (force caused by the swelling of the energy storage element 10 due to aging deterioration, etc.) to the energy storage element 10 closer to the center (for example, the energy storage element adjacent to adjacent member 2 No. 7 in Figure 4 on the central side) is suppressed, thus reducing the variation in performance degradation of each energy storage element 10 compared to the case where all adjacent members 2 have low bending strength.

[0059] Furthermore, in the energy storage device 1 of the above embodiment, the bending strength at each position in the direction of the arrangement of the energy storage elements 10 in the strength distribution of adjacent members 2 is the bending strength of one adjacent member 2, but the configuration is not limited to this. For example, like a moving average, the average value of the bending strength of adjacent members 2 No. 1 to No. 3 in Figure 4, the average value of the bending strength of adjacent members 2 No. 2 to No. 4, the average value of the bending strength of adjacent members 2 No. 3 to No. 6, the average value of the bending strength of adjacent members 2 No. 4 to No. 7, the average value of the bending strength of adjacent members 2 No. 5 to No. 8, the average value of the bending strength of adjacent members 2 No. 6 to No. 9, the average value of the bending strength of adjacent members 2 No. 7 to No. 10, ... may be configured so that the average value of multiple adjacent members 2 that are continuously arranged in the direction of the arrangement of the energy storage elements 10 becomes the distribution shown in Figure 3.

[0060] Furthermore, in the energy storage device 1 of the above embodiment, the holding member 4 has one holding portion (holding region), that is, it holds one laminate L, but the configuration is not limited to this. For example, the holding member 4 may have two or more holding portions by having at least one fixing member (such as a center plate) that is positioned between the energy storage elements 10 at an intermediate position in the X-axis direction and fixed to a pair of connecting members 42, that is, a member whose distance in the X-axis direction from the terminal member 41 does not change due to expansion of the energy storage elements 10, etc.

[0061] More specifically, the holding portion is the region between members whose position in the X-axis direction is fixed with respect to the connecting member 42 (in the above example, it is between the terminal member 41 and the fixing member, and in the example of the above embodiment, it is between the pair of terminal members 41), and a laminate L is arranged in each region. That is, in the energy storage device 1 of the above embodiment, for example, when one fixing member is arranged, the region between the pair of terminal members 41 is partitioned by the fixing member, thereby forming two holding portions (holding regions), and when two fixing members are arranged, the region between the pair of terminal members 41 is partitioned in two places by these two fixing members, thereby forming about three holding portions (holding regions).

[0062] In this case, the holding member 4 holds the same number of laminates L as the number of holding parts, and in each of these multiple laminates L, the bending strength of the adjacent member 2 located in the center in the X-axis direction is greater than the bending strength of the adjacent member 2 closest to the end of the laminate L. At this time, a configuration (strength distribution) is preferred in which, in each of the multiple laminates L, the bending strength of the adjacent member 2 is greater towards the center in the X-axis direction, or more specifically, in each laminate L, the bending strength of each adjacent member 2 increases sequentially from the adjacent member 2 closest to the end in the X-axis direction toward the center in the X-axis direction or the adjacent member 2 closest to the center.

[0063] For example, specifically, if the holding member 4 has one fixing member, the holding member 4 is configured to have two holding parts (a holding part composed of one end member 41, a fixing member and a pair of connecting members 42, and a holding part composed of the other end member 41, a fixing member and a pair of connecting members 42). That is, when the holding member 4 holds two laminates L aligned in the X-axis direction, it is preferable that the distribution of bending strength of adjacent members 2 in each laminate L is greater for adjacent members 2 closer to the center in the X-axis direction, as shown in Figure 5.

[0064] Furthermore, while the above embodiments described a case where the energy storage element is used as a non-aqueous electrolyte secondary battery (e.g., a lithium-ion secondary battery) capable of charging and discharging, the type and size (capacity) of the energy storage element are arbitrary. Also, while the above embodiments described a lithium-ion secondary battery as an example of an energy storage element, the invention is not limited to this. For example, the present invention can be applied to various secondary batteries, as well as primary batteries and capacitors such as electric double-layer capacitors. [Explanation of Symbols]

[0065] 1...Energy storage device, 2, 2C...Adjacent members, 2A...First adjacent member (adjacent member), 2B...Second adjacent member (adjacent member), 21...Intermediate adjacent member (adjacent member), 211...First main body, 215...First restricting part, 22...End adjacent member (adjacent member), 221...Second main body, 2211...Opposite surface, 2212...Protrusion, 225...Second restricting part, 4...Holding member, 41...End member, 411...Through hole, 42...Connecting member, 421...Beam part, 422...End connecting part, 423...Fixing piece, 424...Through hole, 425...Intermediate connecting part, 43...Connecting member, 431...Bolt, 432...Nut, 6...Insulator, 8...Bus bar, 9...Fulfillment point, 10...Energy storage element, 13...Case, 131...Case body, 132...Cover plate, 14...External terminal, L...Laminate, R...Flow path

Claims

1. A laminate including a plurality of energy storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between each energy storage element, It comprises a holding part for holding the laminate, The aforementioned retaining part is A pair of end members arranged on both sides of the laminate in the predetermined direction, It comprises a pair of connecting members that connect the pair of terminal members, Each of the plurality of adjacent members extends between the energy storage elements from one edge to the other edge of the energy storage element in a direction at least perpendicular to the predetermined direction, forming a flow path between adjacent energy storage elements through which a temperature-regulating fluid can flow. In the predetermined direction, the bending strength of the adjacent member located in the center of the laminate is greater than the bending strength of the adjacent member closest to the edge of the laminate. An energy storage device in which the rigidity of each of the pair of terminal members is higher than the rigidity of each of the plurality of adjacent members.

2. A laminate including a plurality of energy storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between each energy storage element, It comprises a holding part for holding the laminate, The aforementioned retaining part is A pair of end members arranged on both sides of the laminate in the predetermined direction, It comprises a pair of connecting members that connect the pair of terminal members, Each of the plurality of adjacent members extends between the energy storage elements from one edge to the other edge of the energy storage element in a direction at least perpendicular to the predetermined direction, forming a flow path between adjacent energy storage elements through which a temperature-regulating fluid can flow. The bending strength of a first adjacent member, which is a predetermined adjacent member in the laminate, is greater than the bending strength of a second adjacent member, which is positioned closer to the end in the predetermined direction than the first adjacent member in the laminate. An energy storage device in which the rigidity of each of the pair of terminal members is higher than the rigidity of each of the plurality of adjacent members.

3. The energy storage device according to claim 1 or 2, wherein in the laminate, the bending strength of the adjacent member closer to the center of the laminate in the predetermined direction is greater than the bending strength of the adjacent member closer to the end of the laminate than the adjacent member.

4. The energy storage device according to any one of claims 1 to 3, wherein in the laminate, adjacent members closer to the center in the predetermined direction have greater bending strength.

5. A laminate including a plurality of energy storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between each energy storage element, It comprises a holding part for holding the laminate, The aforementioned retaining part is A pair of end members arranged on both sides of the laminate in the predetermined direction, It comprises a pair of connecting members that connect the pair of terminal members, Each of the plurality of adjacent members extends from one edge to the other edge of the energy storage element in a direction at least perpendicular to the predetermined direction, between adjacent energy storage elements, forming a flow path through which a temperature-regulating fluid can flow between them. In the laminate, the bending strength of each adjacent member increases sequentially from the adjacent member closest to the end in the predetermined direction toward the center in the predetermined direction or the adjacent member closest to the center. An energy storage device in which the rigidity of each of the pair of terminal members is higher than the rigidity of each of the plurality of adjacent members.

Images