Power storage module and method for manufacturing same

Abstract

A power storage module is provided with: an electrode body including a plurality of electrodes stacked on each other; and a frame body having a shape surrounding the periphery of the electrode body and holding an edge portion of the electrode body. The frame body includes: a pair of outer holding portions that hold an outer end portion of an edge portion of the electrode body in a stacking direction; and an intermediate holding section that is provided between the pair of outer holding sections in the stacking direction and that holds a portion of the edge section of the electrode body other than a portion held by the pair of outer holding sections. The length of the outer holding portion in an orthogonal direction orthogonal to the stacking direction is greater than the length of the middle holding portion in the orthogonal direction.

Description

Technical Field

[0001] The present invention relates to a power storage module and a manufacturing method thereof. Background Art

[0002] Japanese Patent Application Laid-Open No. 2021-15679 discloses a power storage module including: a plurality of power storage cells stacked on each other; a cell housing; and an elastic member disposed in the cell housing. Summary of the invention

[0003] In the power storage module described in Japanese Patent Application Laid-Open No. 2021-15679, warping may occur in the power storage module due to external temperature changes or external forces when the power storage module is mounted in a vehicle.

[0004] An object of the present invention is to provide a power storage module capable of suppressing the occurrence of warping and a method for manufacturing the same.

[0005] According to one aspect of the present invention, a storage battery module comprises: an electrode body comprising a plurality of electrodes stacked on each other; and a frame having a shape surrounding the electrode body and holding an edge of the electrode body, the frame having: a pair of outer retaining portions holding the outer end portions of the edge of the electrode body in a stacking direction; and an intermediate retaining portion disposed between the pair of outer retaining portions in the stacking direction and holding a portion of the edge of the electrode body other than a portion held by the pair of outer retaining portions, wherein a length of the outer retaining portion in an orthogonal direction to the stacking direction is greater than a length of the intermediate retaining portion in the orthogonal direction.

[0006] Furthermore, one aspect of the present invention provides a method for manufacturing a storage battery module, wherein the storage battery module comprises: an electrode body including a plurality of electrodes stacked on each other; and a frame having a shape surrounding the electrode body and holding an edge of the electrode body, the manufacturing method comprising: a stacking step of stacking the electrodes and a holding member holding the edge of the electrode via a separator; and a frame forming step of integrating the holding members by melting them to form the frame, wherein in the stacking step, the electrodes and the holding members are stacked via the separator in such a manner that an outer side surface of the holding member arranged on the outer side in the stacking direction of the electrode body is located closer to the outside in a direction orthogonal to the stacking direction than an outer side surface of the holding member arranged at the center in the stacking direction.

[0007] According to the present invention, it is possible to provide a power storage module capable of suppressing the occurrence of warping and a method for manufacturing the same. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention are described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0009] Figure 1 It is a perspective view schematically showing a power storage module in one embodiment of the present invention.

[0010] Figure 2 is along Figure 1 A cross-sectional view taken along line II-II is shown.

[0011] Figure 3 It is a cross-sectional view schematically showing a stacking step in a method of manufacturing a power storage module.

[0012] Figure 4 It is a cross-sectional view schematically showing a frame body forming step in a method of manufacturing a power storage module.

[0013] Figure 5 It is a cross-sectional view schematically showing a modified example of the method for manufacturing the power storage module.

[0014] Figure 6 It is a cross-sectional view schematically showing a modified example of the method for manufacturing the power storage module.

[0015] Figure 7 It is a cross-sectional view schematically showing a modified example of the method for manufacturing the power storage module.

[0016] Figure 8 It is a cross-sectional view schematically showing a modified example of the method for manufacturing the power storage module. DETAILED DESCRIPTION

[0017] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings referred to below, the same or corresponding components are denoted by the same reference numerals.

[0018] Figure 1 It is a perspective view schematically showing a power storage module in one embodiment of the present invention. Figure 2 is along Figure 1 A cross-sectional view taken along line II-II is shown. Figure 3 It is a cross-sectional view schematically showing a stacking step in a method of manufacturing a power storage module. Figure 4 It is a cross-sectional view schematically showing a frame body forming step in a method of manufacturing a power storage module.

[0019] like Figure 1 and Figure 2 As shown, the power storage module 1 includes an electrode body 100 and a frame body 200. Although not shown in the figure, a power storage device is formed by stacking a plurality of power storage modules 1.

[0020] The electrode body 100 includes a plurality of electrodes 110 and a plurality of separators 120 .

[0021] A plurality of electrodes 110 are stacked one on top of another. Figure 3 As shown, each electrode 110 is composed of a bipolar electrode. Each electrode 110 has a collector foil 112, a positive electrode active material layer 114 provided on one surface of the collector foil 112, and a negative electrode active material layer 116 provided on the other surface of the collector foil 112. In addition, each electrode may be composed of a monopolar electrode (not shown).

[0022] The diaphragm 120 is arranged in the stacking direction of the plurality of electrodes 110 ( Figure 3 The separators 120 are arranged between a pair of electrodes 110 adjacent to each other in the vertical direction (in the vertical direction). Specifically, each separator 120 is arranged between the positive electrode active material layer 114 and the negative electrode active material layer 116. Each separator 120 is formed of an insulating material and allows ions to pass through. As each separator 120, a polyolefin microporous membrane or the like can be cited.

[0023] like Figure 3 As shown, the electrode body 100 has a rim 102 . The rim 102 is composed of a peripheral edge of the current collector foil 112 and a peripheral edge of the separator 120 .

[0024] The frame 200 has a shape surrounding the electrode body 100. The frame 200 holds the edge 102 (see Figure 3 ). The frame 200 is made of an insulating material. The frame 200 is preferably made of a thermoplastic resin (polyethylene, polypropylene, etc.). The frame 200 seals the edge 102 of the electrode body 100. The frame 200 has the function of preventing the electrolyte from leaking from the electrode body 100 and moisture from penetrating into the electrode body 100 from the outside, and the function of ensuring the interval between the electrodes. The frame 200 is formed into a square tube shape.

[0025] The frame body 200 includes a pair of first frame portions 210 and a pair of second frame portions 220 .

[0026] The pair of first frame portions 210 face each other. The pair of first frame portions 210 hold a portion of the edge portion 102 of the electrode body 100. Each first frame portion 210 has a first direction (reference Figure 1 ) extended shape.

[0027] The shape of the first frame portion 210 is set so as to increase the second moment of area. The first frame portion 210 includes a pair of outer holding portions 212 and an intermediate holding portion 214 .

[0028] Each outer holding portion 212 holds an outer end portion in the stacking direction of the edge portion 102 of the electrode body 100 .

[0029] The intermediate holding portion 214 is provided between the pair of outer holding portions 212 in the stacking direction. The intermediate holding portion 214 holds the edge portion 102 of the electrode body 100 other than the portion held by the pair of outer holding portions 212. The intermediate holding portion 214 holds the center portion of the edge portion 102 of the electrode body 100 in the stacking direction.

[0030] like Figure 1 , Figure 2 and Figure 4 As shown, the orthogonal direction ( Figure 2 The length w1 of each outer holding portion 212 in the left-right direction (in the right direction) is greater than the length w2 of the middle holding portion 214 in the orthogonal direction. The length w1 and the length w2 refer to Figure 2 and Figure 4 In this embodiment, the outer side surface 212a of each outer holding portion 212 is located further outward than the outer side surface 214a of the intermediate holding portion 214 in the orthogonal direction. Figure 1 and Figure 2 As shown, the outer side surface 214 a of the intermediate retaining portion 214 may have a shape curved in a convex manner toward the center of the electrode body 100 .

[0031] like Figure 3 and Figure 4 As shown, the length of the portion of the edge 102 of the electrode body 100 held by the intermediate holding portion 214 in the orthogonal direction is smaller than the length of the portion of the edge 102 of the electrode body 100 held by the outer holding portion 212 in the orthogonal direction.

[0032] The pair of second frame portions 220 extend in directions intersecting the first frame portion 210 and face each other. In the present embodiment, each second frame portion 220 extends in a second direction (refer to FIG. 1 ) orthogonal to the first frame portion 210. Figure 1 ) The length of the second frame portion 220 in the second direction is smaller than the length of the first frame portion 210 in the first direction. The pair of second frame portions 220 holds the remaining portion of the edge portion 102 of the electrode body 100 .

[0033] In this embodiment, each second frame portion 220 has the same shape as the first frame portion 210. Figure 1 As shown, the second frame portion 220 has a pair of outer retaining portions 222 and a middle retaining portion 224. However, each second frame portion 220 may be formed in a flat plate shape, and the outer retaining portion 222 and the middle retaining portion 224 may be omitted. In other words, a pair of outer retaining portions and the middle retaining portion may be formed only on each first frame portion 210 constituting the long side portion of the frame body 200 formed in a square tube shape.

[0034] A plurality of injection ports 225 for supplying electrolyte to the electrode assembly 100 may be formed on one of the pair of second frame portions 220 (see Figure 1 ). A plurality of liquid injection ports 225 are arranged at intervals along the second direction. Figure 1 In the figure, for the sake of convenience, three liquid injection ports 225 are shown, but the number of the liquid injection ports 225 is not limited to three.

[0035] A voltage detection terminal (not shown) may be provided at one of the pair of second frame portions 220. The voltage detection terminal is electrically connected to the electrode 110 of the electrode body 100. The voltage detection terminal may be provided at an end portion of the second frame portion 220 in the second direction.

[0036] Next, refer to Figure 3 and Figure 4 Next, a method for manufacturing the power storage module 1 will be described. The manufacturing method includes a stacking step and a frame body forming step.

[0037] In the lamination step, the electrode 110 and the holding member 130 holding the edge of the electrode 110 are stacked with the diaphragm 120 and the intermediary member 140 interposed therebetween.

[0038] Each holding member 130 holds the peripheral edge of the electrode 110. More specifically, each holding member 130 holds the peripheral edge of the collector foil 112. Each holding member 130 is formed of the same material as that of the frame body 200.

[0039] like Figure 3 As shown in FIG. 1 , the length of each holding member 130 in the orthogonal direction gradually increases as it moves toward the outside in the stacking direction. The holding length of the collector foil 112 based on each holding member 130 gradually decreases as it moves from the outside in the stacking direction toward the central portion. In this way, when each holding member 130 is heated in the frame forming process, the thermal influence on the collector foil 112 arranged in the central portion in the stacking direction can be reduced.

[0040] Each intermediary component 140 is disposed between a pair of holding members 130 adjacent to each other in the stacking direction. Each intermediary component 140 is formed of the same material as the material forming the frame body 200. The intermediary component 140 has a function of adjusting the dimension between the pair of holding members 130 adjacent to each other in the stacking direction. In addition, by adjusting the thickness of each holding member 130 in the stacking direction, the intermediary component 140 can be omitted.

[0041] like Figure 3 As shown, in the stacking process, the electrode 110 and the holding member 130 are stacked via the diaphragm 120 and the intermediate member 140. As a result, the outer side surface of the holding member 130 arranged on the outside in the stacking direction is located closer to the orthogonal direction ( ) than the outer side surface of the holding member 130 arranged in the center in the stacking direction. Figure 3 The outer position in the left-right direction).

[0042] In the frame forming step, the holding members 130 and the intermediary members 140 are melted and integrated to form the frame 200. Figure 4 As shown, in the frame forming step, each holding member 130 and each intervening member 140 are heated from the side in the orthogonal direction to melt each holding member 130 and each intervening member 140. In this step, as a means for heating each holding member 130 and each intervening member 140, for example, a heater 10 is used.

[0043] As described above, in the power storage module 1 of the present embodiment, the length w1 of the outer retaining portion 212 in the orthogonal direction is greater than the length w2 of the intermediate retaining portion 214 in the orthogonal direction. Therefore, compared with the case where the length w1 and the length w2 are the same, the second moment of area of ​​each first frame portion 210 becomes larger. The above is also the same for each second frame portion 220. Therefore, the occurrence of warping in the power storage module 1 can be suppressed.

[0044] Hereinafter, modified examples of the above-mentioned embodiment will be described.

[0045] First Modification

[0046] In the method for manufacturing the power storage module 1 according to the first modification, first, Figure 5 As shown in FIG. 1 , the primary sealing portion 135 is formed by heating each holding member 130 and each intermediary member 140 with a heater. The primary sealing portion 135 is formed in a substantially flat plate shape. That is, the outer side surface of the primary sealing portion 135 is formed flat.

[0047] Then, if Figure 6 As shown in FIG. 1 , the reinforcing portion 136 is connected to the outer side of the primary sealing portion 135 by injection molding or the like. The reinforcing portion 136 has a pair of outer retaining portions 212 and an intermediate retaining portion 214. Figure 6 As shown, the outer side surface 214 s of the middle holding portion 214 may be formed substantially parallel to the outer side surface 212 s of the outer holding portion 212 .

[0048] Second Modification

[0049] In the method for manufacturing the power storage module 1 according to the second modification, Figure 7 As shown in FIG. 1 , in the stacking process, the electrode 110 and the holding member 130 are stacked via the diaphragm 120 and the intermediary member 140. Thus, the inner side surface of the holding member 130 disposed on the outside in the stacking direction is located closer to the inside in the orthogonal direction than the inner side surface of the holding member 130 disposed at the center in the stacking direction. In addition, the outer side surface of each holding member 130 and the outer side surface of each intermediary member 140 may be substantially the same plane.

[0050] exist Figure 7 In the example shown, the holding length of the collector foil 112 by each holding member 130 gradually increases from the center in the stacking direction toward the outside. However, the holding length of the collector foil 112 by each holding member 130 may be uniformly set.

[0051] In this example, the inner side surface 212b of each outer holding portion 212 is located further inward than the inner side surface 214b of the middle holding portion 214 in the orthogonal direction. Figure 8 As shown, the inner side surface 214 b of the intermediate retaining portion 214 may have a shape curved so as to be convex in a direction away from the center of the electrode body 100 .

[0052] The above-described exemplary embodiments and examples are understood by those skilled in the art to be specific examples of the following aspects.

[0053] Method 1

[0054] A storage battery module comprises: an electrode body comprising a plurality of electrodes stacked on each other; and a frame having a shape surrounding the electrode body and holding an edge of the electrode body, the frame having: a pair of outer retaining portions holding the outer end portions of the edge of the electrode body in a stacking direction; and an intermediate retaining portion disposed between the pair of outer retaining portions in the stacking direction and holding a portion of the edge of the electrode body other than a portion held by the pair of outer retaining portions, wherein a length of the outer retaining portion in a direction orthogonal to the stacking direction is greater than a length of the intermediate retaining portion in the orthogonal direction.

[0055] In the power storage module, the length of the outer retaining portion in the orthogonal direction is greater than the length of the middle retaining portion in the orthogonal direction. Therefore, compared with the case where the length of each outer retaining portion in the orthogonal direction is the same as the length of the middle retaining portion in the orthogonal direction, the second moment of cross section of the frame becomes larger. Therefore, the occurrence of warping in the power storage module can be suppressed.

[0056] Method 2

[0057] The power storage module according to aspect 1, wherein an outer side surface of each of the pair of outer holding portions is located further outward than an outer side surface of the intermediate holding portion in the orthogonal direction.

[0058] Method 3

[0059] The power storage module according to aspect 2, wherein the outer side surface of the intermediate retaining portion has a shape curved so as to convex toward the electrode body.

[0060] Method 4

[0061] A storage battery module according to any one of methods 1 to 3, wherein a length in the orthogonal direction of a portion of the edge of the electrode body held by the intermediate holding portion is smaller than a length in the orthogonal direction of a portion of the edge of the electrode body held by the outer holding portion.

[0062] Method 5

[0063] A method for manufacturing a storage battery module, the storage battery module comprising: an electrode body, which includes a plurality of electrodes stacked on each other; and a frame, which has a shape surrounding the periphery of the electrode body and holds the edge of the electrode body, the manufacturing method comprising: a stacking step of stacking the electrodes and a holding member holding the edge of the electrode via a separator; and a frame forming step of integrating the holding members by melting each of the holding members to form the frame, in which the electrodes and the holding members are stacked via the separator in such a manner that the outer side surface of the holding member arranged on the outer side in the stacking direction of the electrode body is located closer to the outside in a direction orthogonal to the stacking direction than the outer side surface of the holding member arranged at the center in the stacking direction.

[0064] Method 6

[0065] In the method for manufacturing a power storage module according to aspect 5, in the frame body forming step, each of the holding members is melted by heating the holding members from a side in a direction perpendicular to the stacking direction.

[0066] The embodiments disclosed herein are to be considered in all respects as illustrative and non-restrictive. The scope of the present invention is indicated not by the description of the embodiments above but by the claims, and includes all modifications within the scope of the claims and the meaning equivalent to the claims.

Claims

1. A power storage module, characterized in that: have: an electrode body comprising a plurality of electrodes stacked on top of each other; and a frame having a shape surrounding the periphery of the electrode body and holding the edge of the electrode body, The frame has: a pair of outer holding portions that hold outer ends of the edge portions of the electrode body in a stacking direction of the electrode body; and an intermediate holding portion provided between the pair of outer holding portions in the stacking direction and holding a portion of the edge portion of the electrode body other than a portion held by the pair of outer holding portions, The length of the outer retaining portion in a direction orthogonal to the stacking direction is greater than the length of the intermediate retaining portion in the orthogonal direction.

2. The power storage module according to claim 1, characterized in that: The outer side surface of each of the pair of outer holding portions is located further outward than the outer side surface of the intermediate holding portion in the orthogonal direction.

3. The power storage module according to claim 2, characterized in that: The outer side surface of the intermediate holding portion has a shape curved so as to be convex toward the electrode body.

4. The power storage module according to claim 1, characterized in that: A length of a portion of the edge of the electrode body held by the intermediate holding portion in the orthogonal direction is smaller than a length of a portion of the edge of the electrode body held by the outer holding portion in the orthogonal direction.

5. A method for manufacturing a power storage module, the power storage module comprising: an electrode body including a plurality of electrodes stacked on each other; and a frame having a shape surrounding the periphery of the electrode body and holding an edge of the electrode body, the manufacturing method comprising: a lamination step of laminating the electrodes and a holding member for holding the edge of the electrodes via a separator; and a frame forming step of integrating the holding members by melting the holding members to form the frame; In the stacking process, the electrode and the retaining member are stacked via the diaphragm in such a manner that the outer side surface of the retaining member arranged on the outside in the stacking direction of the electrode body is located closer to the outside in the direction orthogonal to the stacking direction than the outer side surface of the retaining member arranged in the center in the stacking direction.

6. The method for manufacturing a power storage module according to claim 5, characterized in that: In the frame body forming step, each of the holding members is melted by heating the holding members from a side in a direction perpendicular to the stacking direction.

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