JP2022181999A - power storage device - Google Patents

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

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

2. Description of the Related Art Conventionally, an assembled battery in which a plurality of battery cells are constrained in the arrangement direction is known (see Patent Document 1). This assembled battery includes a row of battery cells arranged in one direction, a pair of end plates sandwiching the row of battery cells from both ends in the arrangement direction of the battery cells, and a pair of end plates perpendicular to the arrangement direction. a pair of bind bars that sandwich the plurality of battery cells from different directions and fasten the pair of end plates at both ends in the arrangement direction. In the assembled battery, the plurality of battery cells arranged in a line are tightened in the arrangement direction by a pair of end plates and a pair of bind bars.

In this way, since a row of a plurality of battery cells is tightened in the arrangement direction by a pair of end plates and a pair of bind bars, in this assembled battery, even if each battery cell expands due to deterioration over time, etc. The dimensions in the arrangement direction of the battery do not change. For this reason, the closer to the center of the arrangement direction, the more the expansion of each battery cell accumulates, and the closer to the center the battery cell, the greater the force (pressure) applied from the adjacent battery cells toward the center. The deterioration of the battery performance is greater in the battery cells on the side. That is, the performance deterioration of each battery cell varies.

Since the performance of an assembled battery including a plurality of battery cells is governed by the performance of the most deteriorated battery cell, as described above, the performance deterioration of each battery cell in the assembled battery varies. When the performance deterioration of the battery cells is large, the performance deterioration of the assembled battery progresses rapidly.

JP 2020-177935 A

Accordingly, an object of the present embodiment is to provide a power storage device in which a plurality of power storage elements arranged in a predetermined direction are held by a holding portion, and which is capable of suppressing variations in performance deterioration of the power storage elements. do.

The power storage device of this embodiment is
a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends from at least one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction, between the energy storage elements;
In the predetermined direction, the bending strength of the adjacent member located in the central portion of the stack is greater than the bending strength of the adjacent member closest to the end of the stack.

According to this configuration, even in a state in which the stack is held by the holding portion and the extension of the stack in the X-axis direction is restricted, the adjacent portion arranged in the central portion of the stack in the predetermined direction Since the bending strength of the member is greater than the bending strength of the adjacent member closest to the end, the expansion of each storage element arranged closer to the end of the laminate than the adjacent member arranged in the central portion is greater than that of the central portion. It becomes difficult for the electric energy to be transmitted to the storage element arranged at the position closer to the center of the laminate than the adjacent member arranged at the bottom. As a result, performance deterioration due to expansion of each storage element is suppressed in the storage elements arranged near the center, and as a result, variation in performance deterioration of each storage element is suppressed.

In addition, the power storage device of the present embodiment is
a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends from at least one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction, between the energy storage elements;
The bending strength of the first adjacent member, which is a predetermined adjacent member in the laminate, is greater than the bending strength of the second adjacent member arranged at a position closer to the end in the predetermined direction than the first adjacent member in the laminate. big.

According to this configuration, even in a state in which the laminate is held by the holding portion and the elongation of the laminate in the X-axis direction is restricted, the flexural strength of the first adjacent member is equal to that of the first adjacent member. Since the bending strength of the second adjacent member located closer to the end of the laminate in the predetermined direction than the member is greater than the bending strength, each power storage element located closer to the edge of the laminate than the first adjacent member expands. is less likely to be transmitted to the storage element arranged at a position closer to the center of the laminate than the first adjacent member. As a result, performance deterioration due to expansion of each storage element is suppressed in the storage elements arranged near the center, and as a result, variation in performance deterioration of each storage element is suppressed.

In the power storage device,
Of the two adjacent members 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 edge of the laminate than the adjacent member. may

According to such a configuration, the expansion of each power storage element arranged at a position closer to the end of the laminate than the adjacent member close to the center is such that the expansion of the power storage element is arranged at a position closer to the center of the laminate than the adjacent member close to the center. This makes it difficult for the energy to be transmitted to the elements, thereby suppressing variations in the deterioration of the performance of each storage element.

Further, in the power storage device,
In the laminate, an adjacent member closer to the center in the predetermined direction may have greater bending strength.

According to such a configuration, the expansion of each storage element is less likely to be transmitted to the storage element closer to the center of the stack in a predetermined direction, thereby suppressing variations in performance deterioration of each storage element.

In addition, the power storage device of the present embodiment is
a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends between the adjacent energy storage elements at least from one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction;
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 or the adjacent member closest to the center in the predetermined direction.

Such a configuration also makes it difficult for the expansion of each storage element to be transmitted to the storage element near the center of the stack in a predetermined direction, thereby suppressing variations in performance deterioration of each storage element.

As described above, according to the present embodiment, it is possible to provide a power storage device in which a plurality of power storage elements arranged in a predetermined direction are held by a holding portion, and in which variation in performance deterioration of each power storage element can be suppressed. can be done.

FIG. 1 is a perspective view of a power storage device according to this embodiment. FIG. 2 is an exploded perspective view in which a part of the configuration of the power storage device is omitted. FIG. 3 is a diagram showing bending strength of adjacent members at respective positions in the stacking direction in the power storage device. FIG. 4 is a schematic diagram for explaining the difference in bending strength of adjacent members depending on the position in the stacking direction of the power storage device. FIG. 5 is a diagram showing bending strengths of adjacent members at respective positions in the stacking direction of a power storage device according to another embodiment. FIG. 6 is a schematic diagram for explaining a method of measuring bending strength.

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG. The name of each component (each component) of this embodiment is the one in this embodiment, and may differ from the name of each component (each component) in the background art.

As shown in FIGS. 1 and 2, the electric storage device includes a laminate L including a plurality of electric storage elements 10 and a holding member (holding portion) 4 that holds the laminate L. As shown in FIGS. The power storage device 1 also includes at least one insulator 6 arranged between the laminate L and the holding member 4, and a plurality of bus bars 8 electrically connecting the different power storage elements 10 to each other.

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

Each of the plurality of power storage elements 10 is a primary battery, a secondary battery, a capacitor, or the like. The power storage device 10 of the present embodiment is a chargeable/dischargeable non-aqueous electrolyte secondary battery. More specifically, the power storage device 10 is a lithium ion secondary battery that utilizes electron transfer that occurs with the movement of lithium ions.

Specifically, each electric storage element 10 includes an electrode body, a case 13 that houses the electrode body together with an electrolyte, an external terminal 14 that is at least partially exposed to the outside of the case 13, and the electrode body and the external terminal 14. and a current collector to be connected.

In the electrode assembly, positive electrodes and negative electrodes are alternately laminated with separators interposed therebetween. In this electrode body, lithium ions move between the positive electrode and the negative electrode, thereby charging and discharging the storage element 10 .

The case 13 has a case body 131 having an opening and a plate-like cover plate 132 that closes (closes) the opening of the case body 131 . The case main body 131 of the present embodiment is in the shape of a square tube with a bottom, and the case 13 is in the shape of a rectangular parallelepiped (hexahedral shape). The case 13 of the present embodiment has a flat rectangular parallelepiped shape, and the plurality of power storage elements 10 are arranged in the laminate L so that the wide surface (wall portion) of the case 13 (case main body 131) is connected with the adjacent member 2 interposed therebetween. They are arranged in the X-axis direction while facing each other.

In the following description, the direction in which the plurality of storage elements 10 are arranged (predetermined direction) is 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 the Y-axis of the Cartesian coordinate system, Let the normal direction of the cover plate 132 be the Z-axis of the orthogonal coordinate system.

Each of the plurality of adjacent members 2 has insulating properties, and is a member aligned in the X-axis direction between the storage elements 10 arranged in the X-axis direction, or between the storage elements 10 and the storage elements 10 (in the example of this embodiment, , part of the holding member 4). Each of the plurality of adjacent members 2 of the present embodiment is made of resin.

In addition, each of the plurality of adjacent members 2 forms a flow path R through which temperature-adjusting fluid (cooling fluid such as air in the example of the present embodiment) can flow between adjacent storage elements 10 . The plurality of adjacent members 2 includes a plurality of types of adjacent members, and the plurality of adjacent members 2 of the present embodiment includes an intermediate adjacent member (adjacent member) 21 arranged between the storage elements 10 and the most adjacent member in the X-axis direction. and an end adjacent member 22 that adjoins the storage element 10 on the outside of the storage element 10 at the end. That is, the power storage device 1 includes the intermediate adjacent members 21 and the end adjacent members 22 as the adjacent members 2 . The power storage device 1 of this embodiment includes a plurality of intermediate adjacent members 21 and two (a pair of) end adjacent members 22 . Each of the plurality of intermediate adjacent members 21 is arranged between each storage element 10 .

Each of the plurality of intermediate adjacent members (adjacent members) 21 includes a first main body portion 211 extending in a direction orthogonal to the X-axis direction between the power storage elements 10 adjacent in the X-axis direction, and a power storage device adjacent to the first main body portion 211 . and at least one first restricting portion 215 that restricts movement of the element 10 with respect to the first body portion 211 .

The first body portion 211 is a portion that faces the wide surface of the case 13 of the power storage element 10 and is partly in contact with the wide surface. The first main body portion 211 extends from one edge to the other edge of the adjacent storage element 10 at least in the direction orthogonal to the X-axis direction. Specifically, the first main body portion 211 extends from one end edge to the other end edge of the wide surface of the case 13 of the adjacent electric storage element 10, at least between the two edges facing each other across the center of the wide surface. spreads to The first main body 211 of the present embodiment has the same size as the wide surface of the case 13 or is larger than the wide surface (the size includes the wide surface) when viewed in the X-axis direction. As a result, the first body portion 211 is sandwiched over the entire periphery of the wide surfaces of the cases 13 of the adjacent storage elements 10 .

The first body portion 211 forms a channel R in cooperation with the adjacent storage element 10 so that the fluid for temperature adjustment can flow between the storage element 10 and the storage element 10 . The first main body part 211 of the present embodiment forms a plurality of flow paths R between adjacent power storage elements 10 . Specifically, the first body portion 211 forms a plurality of flow paths R between the energy storage element 10 adjacent on one side in the X-axis direction and the energy storage element 10 adjacent on the other side in the X-axis direction. A plurality of flow paths R are formed between them. The first body portion 211 has a rectangular shape with a size corresponding to that of the adjacent power storage element 10 when viewed from the X-axis direction. A cross section along a plane containing and has a rectangular wave shape.

The first restricting portion 215 extends in the X-axis direction from at least the corners of the rectangular first main body portion 211, and extends between the power storage element 10 (specifically, the case 13) adjacent to the first main body portion 211 and the YZ plane (Y By contacting from the outside in the plane (including the axial direction and the Z-axis direction), the storage element 10 is restricted from moving relative to the first body portion 211 in the YZ plane direction. The first restricting portion 215 of the present embodiment extends from the first body portion 211 toward both sides in the X-axis direction.

Each of the two end adjacent members (adjacent members) 22 extends in a direction orthogonal to the X-axis direction between the energy storage element 10 and the holding member 4 (more specifically, the terminal member 41) that are adjacent in the X-axis direction. It has two body portions 221 and at least one second restriction portion 225 that restricts movement of the storage element 10 adjacent to the second body portion 221 with respect to the second body portion 221 .

The second body portion 221 is a portion that faces the wide surface of the case 13 of the storage element 10 while being partially in contact therewith. The second main body portion 221 extends from one edge to the other edge of the adjacent storage element 10 at least in the direction orthogonal to the X-axis direction. Specifically, the second main body portion 221 extends from one end edge to the other end edge of the wide surface of the case 13 of the adjacent electric storage element 10, at least between the two edges facing each other across the center of the wide surface. spreads to The second body portion 221 of the present embodiment has the same size as the wide surface of the case 13 or is larger than the wide surface (the size includes the wide surface) when viewed in the X-axis direction. In addition, the termination member 41 has the same size as or slightly larger than the power storage element 10 (specifically, the case 13) when viewed from the X-axis direction. 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 storage element 10 over the entire peripheral edge portions thereof.

Like the first body portion 211 of the intermediate adjacent member 21 , the second main body portion 221 also cooperates with the adjacent power storage element 10 to provide a flow path through which a fluid for temperature adjustment can flow between the power storage element 10 and the power storage element 10 . form R. The second body portion 221 of the present embodiment forms a plurality of flow paths R between adjacent storage elements 10 . The second body portion 221 has a rectangular plate shape with a size corresponding to that of the adjacent power storage element 10 when viewed in the X-axis direction. Shape.

Specifically, the second body portion 221 extends in a direction orthogonal to the X-axis direction at one end or the other end of the laminate L in the X-axis direction, and is adjacent to the storage element 10 (case 13). 2211 facing the terminating member 41 and a plurality of ridges 2212 protruding from the facing surface 2211 on the storage element 10 side. Each of the plurality of ridges 2212 extends in the Y-axis direction and is spaced apart in the Z-axis direction.

The second restricting portion 225 extends in the X-axis direction from at least the corners of the rectangular second body portion 221, and extends in the YZ plane direction from the storage element 10 (specifically, the case 13) adjacent to the second body portion 221. The contact from the outside restricts the relative movement of the storage element 10 with respect to the second body portion 221 in the YZ plane direction. The second restricting portion 225 of the present embodiment extends from the second main body portion 221 toward one side in the X-axis direction (the power storage element 10 side).

The plurality of adjacent members 2 (intermediate adjacent members 21) configured as described above include adjacent members 2 having different bending strengths. Specifically, as shown in FIG. 3, the intermediate adjacent member 21 closer to the center in the X-axis direction in the laminate L has a higher bending strength. In this strength distribution graph, the bending strength does not change linearly, but changes curvilinearly toward the center from the ends in the direction in which the electric storage elements 10 are arranged in the laminate L. As shown in FIG. The difference in bending strength between the plurality of intermediate adjacent members 21 is, for example, the difference in the thickness (dimension in the X-axis direction) of the adjacent member 2, the difference in material, the difference in structure (for example, a rectangular shape in a rectangular wave cross section). difference in wave pitch), a combination of these, and so on. Here, as shown in FIG. 6, the flexural strength in this embodiment means that both ends of the adjacent member 2 in the Y direction are supported by fulcrums 9, and the central portion of the YZ plane (the central portion in the Y axis direction) Also, when the central portion in the Z-axis direction) is pushed, the force F when the adjacent member 2 is bent is measured. In addition, each fulcrum 9 supports the adjacent member 2 by a top linearly extending in the Z-axis direction.

Specifically, among the plurality of intermediate adjacent members 21, the intermediate adjacent member 21 arranged in the central portion of the laminate L in the X-axis direction has the highest bending strength, and the end in the X-axis direction (the X-axis direction of the laminate L) The bending strength of the intermediate adjacent member 21 arranged at the position closest to the end portion is the lowest. Note that the intermediate adjacent member 21 arranged in the central portion is one intermediate adjacent member 21 located in the center in the X-axis direction when the number of intermediate adjacent members 21 is an odd number, and the number of intermediate adjacent members 21 is For an even number, it is the two intermediate adjacent members 21 closest to the center in the X-axis direction.

In addition, when the strength distribution of the bending strength of the adjacent member 2 in the laminate L in the X-axis direction (the stacking direction of the power storage element 10) is in the state shown in FIG. The bending strength of the member (for example, No. 7 adjacent member in FIG. 4) 2A is greater than that of the second adjacent member (for example, , adjacent member of No. 3 in Fig. 4) greater than the bending strength of 2B. Further, among the two adjacent members 2 adjacent to each other in the laminate L, the bending strength of the adjacent member (for example, No. 7 adjacent member in FIG. 4) 2A near the center of the laminate L in the X-axis direction is The flexural strength of the adjacent member 2C closer to the end of the laminate L than the member 2A (for example, adjacent member No. 6 in FIG. 4) is greater than that of the member 2A.

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 of this embodiment is composed of only one holding portion. This holding portion is a portion that holds the laminate L in a state where the laminate L is restricted from being stretched in the X-axis direction. In the power storage device 1 of the present embodiment, one holding portion holds one stacked body L, in other words, a plurality of storage elements 10 and a plurality of adjacent members 2 held by one holding portion form one stacked body. Construct L.

The holding member 4 is made of a conductive member such as metal. Specifically, the holding member 4 includes a pair of terminal members 41 arranged on both sides of the laminate L (the plurality of power storage elements 10 arranged in the X-axis direction) in the X-axis direction, and a pair of terminal members 41 connecting the pair of terminal members 41 . and a plurality of connecting members 43 connecting the terminal member 41 and the connecting member 42 .

A pair of terminating members 41 are arranged on both sides of the laminate L in the X-axis direction. Specifically, each of the pair of terminating members 41 is arranged so as to sandwich the end adjacent member 22 between the energy storage element 10 arranged at the end (outermost) in the X-axis direction in the laminate L. Each of the pair of termination members 41 has a rectangular plate shape with a size corresponding to that of the storage element 10 when viewed from the X-axis direction, and the rigidity of each termination member 41 is higher than that of each adjacent member 2 . Specifically, each end member 41 has a rectangular shape elongated in the Y-axis direction, and has a plurality of through holes 411 arranged at intervals in the Z-axis direction at both ends in the Y-axis direction.

Each of the pair of connection members 42 is arranged 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 includes a pair of beams 421 extending in the X-axis direction and spaced apart in the Z-axis direction, and a pair of end connecting portions 422 connecting the ends of the pair of beams 421 to each other. , and an intermediate connecting portion 425 that connects the pair of beam portions 421 at an intermediate position in the X-axis direction. The connecting member 42 of this embodiment has a plurality of intermediate connecting portions 425 .

Each end connecting portion 422 has a fixing piece 423 extending along the outer surface of the termination member 41 in the X-axis direction, and the fixing piece 423 overlaps the through hole 411 of the termination member 41 when viewed from the X-axis direction. It has a through hole 424 at the position.

Each of the plurality of connecting members 43 connects the terminating member 41 and the connecting member 42 while being inserted through the through hole 411 of the terminating member 41 and the through hole 424 of the connecting member 42 (fixed piece 423). Each connecting member 43 of this embodiment is composed of a bolt 431 and a nut 432 .

The insulator 6 has insulating properties. The insulator 6 is arranged between the connection member 42 and the laminate L (the plurality of power storage elements 10). Specifically, the power storage device 1 includes a pair of insulators 6 , and each insulator 6 covers at least a region of the connecting member 42 facing the laminate L, respectively. Thereby, each insulator 6 insulates between the connection member 42 and the plurality of power storage elements 10 included in the laminate L. As shown in FIG.

Each of the plurality of busbars 8 is a plate-like member having conductivity such as metal. Each bus bar 8 electrically connects the external terminals 14 of the storage elements 10 to each other. The plurality of busbars 8 of the present embodiment connect (make conductive) the plurality of power storage elements 10 included in the power storage device 1 in series.

According to the power storage device 1 described above, even when the stack L is held by the holding member 4 and the stack L is restricted from extending in the X-axis direction, The flexural strength of the intermediate adjacent member 21 arranged in the central portion of is greater than the flexural strength of the intermediate adjacent member 21 closest to the ends. For this reason, the expansion of each storage element 10 arranged at a position closer to the end of the laminate L than the intermediate adjacent member 21 arranged in the central portion of the laminate L causes the expansion of the intermediate adjacent member 21 arranged in the central portion. It becomes difficult to transmit to the storage element 10 arranged at a position closer to the center of the laminate L (the center in the X-axis direction). Details are as follows.

When each power storage element 10 swells due to aged deterioration or the like, the dimension of the stacked body L in the X-axis direction is not changed by the holding member 4 (holding portion) (that is, by being connected by the metal connecting member 42, Since the gap between the pair of end members 41 does not change), the bulging of each storage element 10 is accumulated, and the storage element 10 closer to the center in the X-axis direction of the laminate L is subjected to a force applied from the storage elements on both sides in the X-axis direction. (clamping force) tends to increase. However, in the power storage device 1 of the present embodiment, the bending strength of the intermediate adjacent member 21 in the central portion of the laminate L in the X-axis direction is the same as that of the intermediate adjacent member closest to the end (outer end) of the laminate L in the X-axis direction. 21, the bulge of each storage element 10 closer to the end in the X-axis direction of the laminate L than the intermediate adjacent member 21 in the central portion is closer to the X-axis of the laminate L than the intermediate adjacent member 21 in the central portion. It becomes difficult to be transmitted to the electric storage element 10 arranged at a position near the center of the direction.

As a result, in the central power storage element 10, the performance deterioration due to the force applied by the expansion of each power storage element 10 due to the deterioration is suppressed.

In the power storage device 1 of the present embodiment, of the two adjacent members 2 in the laminate L, the bending strength of the intermediate adjacent member 21 closer to the center of the laminate L in the X-axis direction is greater than that of the intermediate adjacent member 21. It is greater than the bending strength of the intermediate adjacent member 21 near the end of the laminate L. For this reason, the expansion of each storage element 10 arranged at a position closer to the end of the laminate L than the intermediate adjacent member 21 closer to the center in the X-axis direction of the laminate L causes the stack to expand more than the intermediate adjacent member 21 closer to the center. It becomes difficult to transmit to the electric storage element 10 arranged at a position close to the center of the body. As a result, variation in performance deterioration of each storage element 10 can be suppressed.

In addition, in the power storage device 1 of the present embodiment, the bending strength of the intermediate adjacent member 21 closer to the center in the X-axis direction in the laminate L is greater. Therefore, the expansion of each storage element 10 is less likely to be transmitted to the storage element 10 closer to the center of the laminate L in the X-axis direction, thereby suitably suppressing variations in performance deterioration of each storage element 10 .

Moreover, if the bending strength of all intermediate adjacent members 21 is increased, the thickness of each intermediate adjacent member 21 is increased, and the dimension of power storage device 1 (laminated body L) in the X-axis direction is increased. If the intermediate adjacent member 21 is made of a material that is more expensive than resin such as resin, the manufacturing cost of the power storage device 1 increases. By increasing the strength of the intermediate adjacent member 21 and decreasing the strength of the intermediate adjacent member 21 near the end of the laminate L in the X-axis direction, each power storage element can be manufactured while suppressing the increase in size and manufacturing cost. 10, the variation in performance deterioration can be suitably suppressed.

It should be noted that the power storage device of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the gist of the present invention. For example, the configuration of one embodiment can be added to the configuration of another embodiment, and part of the configuration of one embodiment can be replaced with the configuration of another embodiment. Furthermore, some of the configurations of certain embodiments can be deleted.

In the power storage device 1 of the above embodiment, the intermediate adjacent member 21 closer to the center in the X-axis direction in the laminate L has a higher bending strength, but the configuration is not limited to this.

For example, the bending strength of a predetermined number of adjacent members (for example, No. 5 to No. 10 adjacent members in FIG. 4) 2 in the central portion of the laminate L in the X-axis direction is The bending strength of the adjacent members 2 (for example, adjacent members No. 1 to No. 4 and No. 11 to No. 14 in FIG. 4) may be greater than the bending strength. In this case, the flexural strength of each of the predetermined number of adjacent members 2 may be the same, or the adjacent member 2 closer to the center may have a greater bending strength.

In addition, among the plurality of adjacent members 2, some of the adjacent members 2 (for example, No. 3 to No. 7 adjacent members in FIG. 4) may have a configuration in which the bending strength of the adjacent member 2 closer to the center is greater. Even with such a configuration, the power storage element 10 near the center (for example, the power storage element adjacent to the adjacent member 2 of No. 7 in FIG. Since the force caused by the bulging of the elements 10) is suppressed, the variation in performance deterioration of the storage elements 10 is suppressed compared to the case where all of the adjacent members 2 have a small bending strength.

In addition, the bending strength at each position in the arrangement direction of the storage elements 10 in the strength distribution of the adjacent members 2 in the electricity storage device 1 of the above-described embodiment is the bending strength of one adjacent member 2, but is not limited to this configuration. . For example, like the moving average, No. in FIG. 1 to No. 3, the average value of the bending strength of the adjacent member 2, No. 2 to No. 4, the average value of the bending strength of the adjacent member 2, No. 3 to No. Average value of bending strength of adjacent member 2 of No. 6; 4 to No. 7, the average value of the bending strength of the adjacent member 2, No. 7; 5 to No. 8, the average value of the bending strength of the adjacent member 2, No. 6 to No. 9, the average value of the bending strength of the adjacent member 2, No. 7 to No. The average value of the flexural strengths of the ten adjacent members 2, . may be configured.

In addition, in the power storage device 1 of the above-described embodiment, the holding member 4 has one holding portion (holding region), that is, holds one laminate L, but is not limited to this configuration. For example, the holding member 4 is a fixing member (such as a center plate) that is disposed between the storage elements 10 at an intermediate position in the X-axis direction and is fixed to the pair of connection members 42 , that is, a terminal member that is disposed when the storage elements 10 expand or the like. Two or more holding portions may be provided by providing at least one member that does not change the distance from the member 41 in the X-axis direction.

More specifically, the holding portion is located between members whose positions in the X-axis direction are fixed with respect to the connection member 42 (in the above example, between the terminal member 41 and the fixed member, and in the example of the above embodiment, , between a pair of terminal members 41), and the laminate L is arranged in each region. That is, in the power storage device 1 of the above-described embodiment, for example, when one fixing member is arranged, the fixing member partitions the region between the pair of end members 41 to form two holding portions (holding regions). When two fixing members are arranged, the area between the pair of end members 41 is partitioned at two points by these two fixing members, thereby forming three holding portions (holding areas).

In this case, the holding member 4 holds the same number of laminates L as the number of holding portions, and in each of the plurality of laminates L, the bending strength of the adjacent member 2 arranged in the central portion in the X-axis direction is , is greater than the bending strength of the adjacent member 2 closest to the edge of the laminate L. At this time, in each of the plurality of laminates L, the configuration (strength distribution) in which the bending strength increases toward the adjacent member 2 closer to the center in the X-axis direction. A configuration (strength distribution) in which the bending strength of each adjacent member 2 increases in order from the adjacent member 2 closest to the end toward the center or the adjacent member 2 closest to the center in the X-axis direction is preferable.

For example, specifically, the holding member 4 has one fixing member, so that the holding member 4 has two holding portions (a holding portion configured by one end member 41, a fixing member, and a pair of connection members 42, and , the other end member 41, a fixing member, and a pair of connection members 42), that is, when the holding member 4 holds two laminates L aligned in the X-axis direction, 5, it is preferable that the distribution of the bending strength of the adjacent members 2 in each laminate L increases toward the adjacent members 2 closer to the center in the X-axis direction.

In addition, in the above embodiment, the storage element is used as a chargeable/dischargeable non-aqueous electrolyte secondary battery (for example, a lithium-ion secondary battery), but the type and size (capacity) of the storage element are arbitrary. is. Also, in the above embodiments, a lithium ion secondary battery has been described as an example of a storage element, but the storage element is not limited to this. For example, the present invention can be applied to various secondary batteries, primary batteries, and electric storage elements of capacitors such as electric double layer capacitors.

Reference Signs List 1 power storage device 2, 2C adjacent member 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 body part 2211... Opposing surface 2212... Protruding strip 225... Second restricting part 4... Holding member 41... Terminal member 411 Through hole 42 Connecting member 421 Beam 422 End connecting portion 423 Fixed piece 424 Through hole 425 Intermediate connecting portion 43 Connecting member 431 Bolt 432... Nut, 6... Insulator, 8... Bus bar, 9... Fulcrum, 10... Power storage element, 13... Case, 131... Case main body, 132... Lid plate, 14... External terminal, L... Laminated body, R... Flow path

Claims (5)

a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends from at least one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction, between the energy storage elements;
The power storage device, wherein, in the predetermined direction, the flexural strength of the adjacent member arranged in the central portion of the stack is greater than the flexural strength of the adjacent member closest to an end of the stack. a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends from at least one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction, between the energy storage elements;
The bending strength of the first adjacent member, which is a predetermined adjacent member in the laminate, is greater than the bending strength of the second adjacent member arranged at a position closer to the end in the predetermined direction than the first adjacent member in the laminate. Large power storage device. Of the two adjacent members 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 edge of the laminate than the adjacent member. , The power storage device according to claim 1 or 2. 4. The power storage device according to claim 1, wherein an adjacent member closer to the center in said predetermined direction in said laminate has greater bending strength. a laminate including a plurality of storage elements arranged in a predetermined direction and a plurality of adjacent members arranged between the storage elements;
and a holding part that holds the laminate,
each of the plurality of adjacent members extends between the adjacent energy storage elements at least from one edge to the other edge of the energy storage element in a direction orthogonal to the predetermined direction;
A power storage device, wherein 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 or the adjacent member closest to the center in the predetermined direction.

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