power storage module

Abstract

The power storage module includes: a power storage device; a holder that holds the power storage device; and a reinforcing member of the holder. The power storage device includes: a plurality of electrode bodies that are cylindrical; and a thin film outer body that has a plurality of accommodation portions that respectively surround the plurality of electrode bodies, and a sealing portion that seals each of the accommodation portions and links the plurality of accommodation portions to each other. The holder has a side plate that extends in an arrangement direction of the plurality of electrode bodies, and the side plate has a plurality of recessed portions that are side by side in the arrangement direction and in which each of the accommodation portions is fitted. The reinforcing member extends in the arrangement direction and is side by side with the holder in an axial direction of the electrode bodies, and a first groove portion in which the side plate is fitted is provided in a surface that faces the holder.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a power storage module. BACKGROUND

[0002] Conventionally, a power storage module (for example, refer to Patent Literature 1) in which a plurality of cylindrical power storage devices (for example, batteries) are mounted is known. In the power storage module disclosed in Patent Literature 1, each power storage device has a cylindrical exterior can, and a wound-type electrode body is housed in each exterior can.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT LITERATURE

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2014-170613 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] A power storage module can be used as a power source for a vehicle or a portable terminal. Therefore, it is desirable to reduce the weight of the power storage module. As a method of reducing the weight of the power storage module, it is considered to seal a plurality of electrode bodies with a common thin film exterior body while maintaining the seal of each. Thereby, the exterior cans that house the electrode bodies can be eliminated, and thus the power storage module can be reduced in weight. On the other hand, from the viewpoint of the flexibility of the thin film exterior body, a power storage device having a configuration in which a plurality of electrode bodies are sealed with a thin film exterior body is likely to be largely deformed due to an impact or the like. Therefore, it is desirable to improve the retention strength of the power storage device.

[0008] The present disclosure has been made in view of such circumstances, and one of the objects thereof is to provide a technology for improving the retention strength of a power storage device having a configuration in which a plurality of electrode bodies are sealed with a thin film exterior body.

[0009] MEANS FOR SOLVING PROBLEMS

[0010] One embodiment of the present disclosure is a power storage module. The power storage module includes a power storage device, a holder that holds the power storage device, and a reinforcing member of the holder. The power storage device includes a plurality of electrode bodies that are cylindrical, and a thin film exterior body that includes a plurality of accommodation portions that accommodate the plurality of electrode bodies, respectively, and a sealing portion that seals each of the accommodation portions and links the plurality of accommodation portions to each other. The holder includes a side plate that extends in an arrangement direction of the plurality of electrode bodies, and the side plate includes a plurality of recesses that are arranged side by side in the arrangement direction and in which each of the accommodation portions is fitted. The reinforcing member extends in the arrangement direction and is arranged side by side with the holder in an axial direction of the electrode bodies, and a first groove portion in which the side plate is fitted is provided in a surface of the reinforcing member that faces the holder.

[0011] Any combination of the above-described structural elements, and a mode obtained by converting the description of the present disclosure between a method, a device, a system, and the like, is also effective as a mode of the present disclosure.

[0012] - Invention Effects -

[0013] According to the present disclosure, it is possible to improve the retention strength of a power storage device having a configuration in which a plurality of electrode bodies are sealed by a thin film outer body. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a perspective view of a power storage device with which the embodiment is involved.

[0015] Figure 2 (A) of is a schematic view of the power storage device as viewed from the axial direction. Figure 2 (B) of is a schematic view of the power storage device as viewed from the second direction.

[0016] Figure 3 (A) to Figure 3 (C) of is a process view of a manufacturing method of the power storage device.

[0017] Figure 4 (A) to Figure 4 (C) of is a process view of a manufacturing method of the power storage device.

[0018] Figure 5 is a perspective view of a power storage module to which the embodiment is involved.

[0019] Figure 6 is an exploded perspective view of the power storage module.

[0020] Figure 7 (A) of is a plan view of a reinforcing member, Figure 7 (B) of is a perspective view of a retainer.

[0021] Figure 8 is a perspective view of a part of a power storage module to which a modification example is involved. DETAILED DESCRIPTION

[0022] Hereinafter, the present disclosure will be described based on appropriate embodiments with reference to the drawings. The embodiments are merely examples and do not limit the present disclosure, and all features described in the embodiments, combinations thereof are not necessarily essential to the present disclosure. Identical or equivalent structural elements, members, processes shown in each drawing are given the same symbols, and repeated description is appropriately omitted. Furthermore, the scale, shape of each part shown in each drawing is set for easy explanation, and is not limited unless specifically mentioned. Furthermore, in the case where the terms "first", "second", and the like are used in the present specification or claims, the terms do not mean any order, importance unless specifically mentioned. Furthermore, a part of members that are not important in explaining the embodiments is omitted in each drawing.

[0023] Figure 1 FIG. 1 is a perspective view of a power storage device 1 according to an embodiment. Figure 2 (A) of FIG. 1 is a schematic view of the power storage device 1 as viewed from an axial direction A. Figure 2 (B) of FIG. 1 is a schematic view of the power storage device 1 as viewed from a second direction C. In Figure 2 (B) of FIG. 1, the inside of the film exterior 4 is also illustrated for convenience of explanation. Further, the state before the film exterior 4 is folded is illustrated by a broken line. In the present embodiment, the direction in which the winding axis of the electrode body 2 extends is set as the axial direction A, the direction in which the plurality of electrode bodies 2 are arranged is set as a first direction B, and the direction orthogonal to the axial direction A and the first direction B is set as a second direction C.

[0024] The power storage device 1 of the present embodiment is, for example, a rechargeable secondary battery such as a lithium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, or the like, or a capacitor such as an electric double layer capacitor. The power storage device 1 has a plurality of electrode bodies 2 and a film exterior 4. The power storage device 1 of the present embodiment has eight electrode bodies 2, but the number thereof is not particularly limited and can be two or more.

[0025] Each electrode body 2 is cylindrical and has a winding structure in which a strip-shaped first electrode plate and a strip-shaped second electrode plate sandwich an electrode separator and are stacked and wound. As one example, the first electrode plate is a negative electrode plate and the second electrode plate is a positive electrode plate. A first electrode lead 8 is electrically connected to the first electrode plate. A second electrode lead 10 is electrically connected to the second electrode plate. The first electrode lead 8 and the second electrode lead 10 are, for example, strips and each one end thereof is welded to each electrode plate. The plurality of electrode bodies 2 are set in a posture such that the axial direction A of each electrode body 2 is parallel to each other and are arranged in the first direction B with a prescribed interval therebetween. The plurality of electrode bodies 2 are surrounded by the common film exterior 4.

[0026] The film exterior 4 has, for example, a structure in which two laminated films are stacked. Each laminated film has, for example, a structure in which a thermoplastic resin sheet is stacked on both surfaces of a metal sheet of aluminum or the like. Further, the film exterior 4 has a plurality of accommodation portions 12 and a sealing portion 14. The plurality of accommodation portions 12 are arranged in the first direction B with a prescribed interval therebetween. Each accommodation portion 12 is cylindrical and accommodates each electrode body 2. Each accommodation portion 12 includes a pocket portion provided to the film exterior 4. The pocket portion is a portion that is separated from each other in the two laminated films. Therefore, each accommodation portion 12 protrudes from the sealing portion 14 along the shape of the side surface of the electrode body 2. The electrode body 2 and an electrolyte 16 are accommodated in each accommodation portion 12.

[0027] The seal portion 14 seals each of the accommodation portions 12 by surrounding the outer periphery of each of the accommodation portions 12. The seal portion 14 is formed of, for example, a fusion portion of thermoplastic resin sheets. The fusion portion is obtained by performing a heat-seal treatment on the outer periphery of the bag portion of the film exterior 4, and fusing the thermoplastic resin sheets of two laminated films to each other. The seal portion 14 seals each of the accommodation portions 12 and links the plurality of accommodation portions 12 to each other.

[0028] The end portions of the first electrode lead 8 and the second electrode lead 10 on the side opposite to the side connected to the electrode body 2 protrude outward of the film exterior 4. The interface between each of the electrode leads and the film exterior 4 is sealed with a known sealant. In the present embodiment, the first electrode lead 8 and the second electrode lead 10 connected to each of the electrode bodies 2 protrude to opposite sides in the axial direction A. Further, each of the first electrode leads 8 protrudes to the same side. Alternatively, the first electrode lead 8 and the second electrode lead 10 can protrude to the same side in the axial direction A.

[0029] The film exterior 4 is folded or bent between the adjacent accommodation portions 12 and extends in a zigzag shape. By folding the film exterior 4 in a zigzag shape, the interval of each of the accommodation portions 12 in the first direction B can be narrowed compared to the state before the folding, and thus the length of the power storage device 1 in the first direction B can be shortened. Further, the plurality of accommodation portions 12 of the present embodiment are arranged such that, in the state in which the film exterior 4 extends in a zigzag shape, the centers of the respective accommodation portions 12 are aligned on the same straight line in the axial direction A. Thus, compared to a case in which the plurality of accommodation portions 12 are arranged such that the centers thereof are deviated in the second direction C, the size of the power storage device 1 in the second direction C can be suppressed from becoming large. Further, the seal portion 14 bent in a zigzag shape converges more inward in the second direction C than the accommodation portions 12. Thus, the size of the power storage device 1 in the second direction C can be suppressed from becoming large by the folding of the film exterior 4. Alternatively, in the present disclosure, the centers of the plurality of accommodation portions 12 can not necessarily be located on the same straight line.

[0030] The seal portion 14 has a pair of first edge portions 14a and a pair of second edge portions 14b that surround the periphery of each of the accommodation portions 12. The pair of first edge portions 14a sandwich each of the accommodation portions 12 and extend in parallel in the axial direction A, and seal the end portions of each of the accommodation portions 12 in the axial direction A. The first edge portion 14a of the present embodiment extends linearly across the center of the accommodation portion 12 in the axial direction A. The pair of second edge portions 14b sandwich each of the accommodation portions 12 and extend in parallel in a direction orthogonal to the axial direction A, and link the pair of first edge portions 14a in the axial direction A.

[0031] The two second sides 14b located between two adjacent receiving portions 12 have a mutually defined angle θ, in other words, they are connected non-linearly. Furthermore, the direction of bending or curving of the connecting portion of the two second sides 14b differs among the multiple connecting portions arranged side-by-side in the first direction B. As a result, the film outer casing 4 extends in a zigzag shape in the first direction B.

[0032] The following is an example of a method for manufacturing the energy storage device 1. Figure 3 (A) Figure 3 (C) and Figure 4 (A) Figure 4 (C) is a process diagram of the manufacturing method of the energy storage device 1. First, as shown in Figure 1... Figure 3 As shown in (A), a first laminated film 20a is prepared. A plurality of semi-cylindrical recesses 18 are pre-formed in the first laminated film 20a. The plurality of recesses 18 are formed, for example, by a known process such as stamping the first laminated film 20a. An electrode body 2 is placed in each recess 18. A first electrode lead 8 and a second electrode lead 10 are pre-connected to the electrode body 2. A sealant (not shown) is applied to the first electrode lead 8 and the second electrode lead 10.

[0033] Next, as Figure 3 As shown in (B), the second laminated film 20b overlaps with the first laminated film 20a to form the film outer casing 4. In the second laminated film 20b, semi-cylindrical recesses 18 are provided at positions opposite to the recesses 18 of the first laminated film 20a. Therefore, by overlapping the first laminated film 20a and the second laminated film 20b, a bag portion, or in other words, a receiving portion 12, is formed by a pair of recesses 18. The method for forming the recesses 18 of the second laminated film 20b is the same as the method for forming the recesses 18 of the first laminated film 20a. With the electrode body 2 housed in the receiving portion 12, the tip of the first electrode lead 8 and the tip of the second electrode lead 10 protrude outwards from the film outer casing 4.

[0034] Next, as Figure 3 As shown in (C), a portion of the film outer casing 4 is heat-pressed to form a welded portion 22. The portion of the film outer casing 4 that is not heat-pressed is a non-welded portion 24. The non-welded portion 24 is configured to connect each receiving portion 12 to the outside of the film outer casing 4. In this embodiment, the non-welded portion 24 is provided such that the protruding edge of the first electrode lead 8 among the four sides of each receiving portion 12 is connected to the outside of the film outer casing 4. The remaining three sides of each receiving portion 12 are surrounded by the welded portion 22. The interface between the film outer casing 4 and the second electrode lead 10 is sealed with sealant.

[0035] Next, as Figure 4As shown in (A), electrolyte 16 is injected into each receiving portion 12 via the non-soldering portion 24. After the electrolyte 16 is injected, as... Figure 4 As shown in (B), the non-fused portion 24 is also subjected to heat-pressing treatment. As a result, a sealing portion 14 is formed around the entire circumference of each receiving portion 12. The interface between the thin film outer casing 4 and the first electrode lead 8 is sealed with sealant. Next, as Figure 4 As shown in (C), the thin-film outer casing 4 is bent into a zigzag shape. Through the above processes, the energy storage device 1 is obtained.

[0036] Furthermore, the manufacturing method of the energy storage device 1 is not limited to the above. For example, a laminated film with a length twice that of the energy storage device 1 can be used, and the laminated film can be folded in half to surround each electrode body 2. In addition, when the required amount of electrolyte 16 is small, the inter-electrode separator can be pre-wetted with electrolyte 16, thereby eliminating the need for... Figure 4 The electrolyte 16 injection process shown in (A). In this case, Figure 3 In the hot pressing process shown in (C), the entire circumference of each receiving part 12 is subjected to hot pressing treatment to form the sealing part 14.

[0037] The energy storage device 1 is assembled into the energy storage module 100 of this embodiment, as described below. Figure 5 This is a perspective view of the energy storage module 100 according to the implementation method. Figure 6 This is an exploded 3D view of the energy storage module 100. Figure 7 (A) is a top view of the reinforcing member 128. Figure 7 (B) is a perspective view of cage 104.

[0038] The energy storage module 100 includes: an energy storage device 1, a retainer 104, reinforcing members 128, and a busbar 108 (current collector). Furthermore, the energy storage module 100 of this embodiment includes multiple energy storage devices 1. As an example, one energy storage device 1, one retainer 104, and two reinforcing members 128 are combined to form a device unit 130, and the energy storage module 100 includes two device units 130. The number of device units 130 included in the energy storage module 100 is not particularly limited; it can be one or more than three. Furthermore, multiple energy storage devices 1 can be assembled in one retainer 104 within the device unit 130. Additionally, one or more reinforcing members 128 can be assembled in one retainer 104.

[0039] The device units 130 are arranged in the second direction C. Further, the device units 130 are set in a posture such that the housing portions 12 of the power storage devices 1 are arranged side by side in the same direction. Two power storage devices 1 adjacent in the second direction C are arranged offset from each other in the first arrangement direction B such that the axis of the electrode body 2 of one power storage device 1 is disposed between the axes of the electrode bodies 2 of the other power storage device 1. In other words, the recesses of the two housing portions 12 of one power storage device 1 are fitted with the housing portions 12 of the other power storage device 1. Thus, the size of the power storage module 100 in the second direction C can be reduced.

[0040] In each device unit 130, the power storage device 1 is held by the holder 104. The holder 104 has a side plate 112 and a pair of protruding portions 114. The side plate 112 is a rectangular plate extending in the first direction B. The pair of protruding portions 114 are rectangular plates protruding from both ends of the side plate 112 in the first direction B in a direction intersecting the first direction B and the axis direction A. The protruding portions 114 of the present embodiment protrude in the second direction C. The pair of protruding portions 114 are opposed to each other in the first direction B. Thus, the holder 104 has a substantially U-shaped form that is longer in the first direction B. The holder 104 is set in a posture such that the major surface of the side plate 112 faces the second direction C and the major surfaces of the protruding portions 114 face the first direction B.

[0041] The holder 104 is composed of one sheet of a plate material as one example. The side plate 112 and the pair of protruding portions 114 can be formed by performing bending processing on both end portions of a metal plate. Alternatively, the holder 104 can be made of resin if a prescribed rigidity or more can be obtained. Further, the holder 104 can be composed of the side plate 112 and the protruding portions 114 joined to each other as independent members. As a metal for the holder 104, for example, aluminum, aluminum alloy, steel, or the like is exemplified. Further, as a resin for the holder 104, for example, a thermoplastic resin such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), Noryl (registered trademark) resin (modified PPE), or the like; a fiber-reinforced plastic (FRP) such as carbon fiber-reinforced plastic, glass fiber-reinforced plastic, or the like is exemplified.

[0042] The power storage device 1 is surrounded by the holder 104 on three sides in the first direction B and the second direction C. The side plate 112 covers one side of the power storage device 1 in the second direction C. The pair of protruding portions 114 cover both sides of the power storage device 1 in the first direction B. As one example, the side plate 112 is fixed to the opposing power storage devices 1 by an adhesive. The adhesive is preferably an insulating adhesive. Alternatively, an insulating sheet can be present between the power storage device 1 and the holder 104.

[0043] The power storage devices 1 are arranged in the second direction C in a state in which the holders 104 are assembled. At this time, each power storage device 1 is configured so that an exposed surface that is not covered by the holder 104 faces the same direction. In a state in which the power storage devices 1 are arranged, the exposed surface of each power storage device 1 is covered by the side plate 112 of the adjacent device unit 130 and is fixed by the adhesive. Thus, at least a portion of the power storage device 1 is sandwiched by two side plates 112. Further, at least a portion of the side plate 112 is sandwiched by two power storage devices 1.

[0044] Further, each protrusion 114 has a leading end portion 114a and a base end portion 114b. The base end portion 114b is present between the side plate 112 and the leading end portion 114a. The leading end portion 114a is offset from the base end portion 114b in a direction away from the power storage device 1. Thus, the interval of the pair of protrusions 114 on the leading end portion 114a side is wider than that on the base end portion 114b side. Also, each leading end portion 114a protrudes to a position overlapping the base end portion 114b of the adjacent holder 104 as viewed in the first direction B.

[0045] In other words, if the plurality of device units 130 are arranged in the second direction C, in the adjacent two holders 104, the side plate 112 and the pair of base end portions 114b in the other holder 104 enter between the pair of leading end portions 114a in one holder 104. Also, the portion in which the leading end portion 114a of one holder 104 and the base end portion 114b of the other holder 104 coincide is subjected to a known joining process such as laser welding. As a result, the holders 104 are joined, and the plurality of device units 130 are integrated.

[0046] The side plate 112 has a plurality of recesses 112a side by side in the first direction B. Each recess 112a is a groove extending in the axial direction A. Also, in a state in which the holder 104 is assembled in the power storage device 1, each accommodation portion 12 of the power storage device 1 opposite the side plate 112 is fitted into each recess 112a. As a result, the side plate 112 extends along the curved surface of each accommodation portion 12. Thus, it is possible to more stably hold the power storage device 1. In particular, it is possible to restrict displacement of the power storage device 1 in the first direction B.

[0047] Further, the side plate 112 of the present embodiment is a wave-shaped plate in which concave portions 112a and convex portions 112b are alternately arranged in the first direction B. In other words, from one main surface side, the concave portions 112a and the convex portions 112b are alternately arranged in the first direction B. Therefore, each housing portion 12 of the power storage device 1 arranged with the side plate 112 interposed therebetween can be fitted into the side plate 112. Specifically, with respect to the concave portions 112a and the convex portions 112b when the side plate 112 is viewed from one main surface side, each housing portion 12 of one power storage device 1 is fitted into each concave portion 112a. Further, in each convex portion 112b (which is a concave portion when viewed from the opposite side), each housing portion 12 of the other power storage device 1 is fitted from the back surface side. Thus, the stability of each power storage device 1 in the power storage module 100 can be further improved. In addition, the side plate 112 can be a plate having a thickness greater than a wave-shaped plate, and a plurality of concave portions arranged on both surfaces in the first direction B.

[0048] The device unit 130 located at one end in the second direction C does not have another device unit 130 on the exposed surface side. Therefore, the exposed surface of the power storage device 1 in this device unit 130 has an assembly end holder (not shown) attached thereto. The end holder as an example has the same shape as the holder 104 except that the protruding direction of the protruding portion 114 is opposite to that of the holder 104 and the protruding portion 114 does not have a front end portion 114a.

[0049] Further, the side plate 112 and the pair of protruding portions 114 of the present embodiment are provided with a plurality of through holes 132. The plurality of through holes 132 provided in the side plate 112 pass through the side plate 112 in the plate thickness direction of the side plate 112. Further, the plurality of through holes 132 are arranged in a matrix shape. Similarly, the plurality of through holes 132 provided in each protruding portion 114 pass through the protruding portion 114 in the plate thickness direction of the protruding portion 114. Further, the plurality of through holes 132 are arranged in a matrix shape. By providing the through holes 132, the power storage module 100 can be made lighter.

[0050] The reinforcing member 128 is a member that fits into the holder 104 to increase the rigidity of the holder 104. The reinforcing member 128 is arranged side by side with the holder 104 in the axial direction A. In the present embodiment, the reinforcing member 128 is arranged on both sides of the holder 104 in the axial direction A. Therefore, the holder 104 is sandwiched by the pair of reinforcing members 128 in the axial direction A.

[0051] Each reinforcing member 128 is a flat bar shape that is longer in the first direction B and is arranged with two main surfaces facing the axial direction A. Therefore, one main surface faces the holder 104 side. The reinforcing member 128 has a first groove portion 134 into which the side plate 112 is fitted on the main surface facing the holder 104 side. In the first groove portion 134, the edge portion of the side plate 112 in the axial direction A is fitted. Since the side plate 112 of the present embodiment is a wave-shaped plate, the first groove portion 134 is wavy.

[0052] Further, the reinforcing member 128 of the present embodiment has a pair of the second groove portions 136 into which the protruding portions 114 are fitted on the main surface on the side of the holder 104. Alternatively, the reinforcing member 128 can not have the second groove portions 136. In the second groove portions 136, the edge portions of the protruding portions 114 in the axial direction A are fitted. The second groove portions 136 extend in the second direction C from both ends of the first groove portion 134 in the first direction B. In a part of the second groove portions 136, two pieces of the protruding portions 114 are fitted. Specifically, the leading end portion 114a of one of the holders 104 and the base end portion 114b of the other holder 104 adjacent in the second direction C are fitted.

[0053] Further, the first groove portion 134 and the second groove portion 136 of the present embodiment are connected to each other. As one example, the end portion of the first groove portion 134 in the first direction B is connected to the second groove portion 136. With this structure, the corner portion of the side plate 112 and the protruding portion 114 of the holder 104 can be accommodated in the groove portion. As a result, the holder 104 can be held more firmly. Alternatively, the second groove portion 136 can not be connected to the first groove portion 134.

[0054] Further, the axial direction A of each of the protruding portions 114 of the present embodiment is uniform, but is not limited to this structure. For example, the leading end portion 114a of each of the protruding portions 114 can be cut at both ends or one end in the axial direction A. With this structure, the protruding portion 114 fitted into the second groove portion 136 can be limited to the part of the holder 104 in which the side plate 112 is fitted into the first groove portion 134 of the reinforcing member 128 in which the second groove portion 136 is provided. In other words, one piece of the protruding portion 114 is fitted into any of the second groove portions 136. Thus, the shape of the groove provided in the holder 104 can be unified regardless of the position of the holder 104 with respect to the power storage module 100, in other words, regardless of whether the holder 104 is disposed at the end in the second direction C or at the central side in the second direction C. Alternatively, as one example, the axial direction A of the leading end portion 114a cut at the end in the axial direction A is equal to the distance between the two reinforcing members 128 sandwiching the holder 104 in the axial direction A.

[0055] Further, the reinforcing member 128 has an insulating property and has a mounting portion 138 of the bus bar 108. In other words, the reinforcing member 128 functions as an insulating plate that supports the bus bar 108. The mounting portion 138 is provided to a main surface of the reinforcing member 128 on the side opposite to the holder 104. The mounting portion 138 is, for example, a recess formed in the main surface in conformity with the shape of the bus bar 108. As one example, the depth of the mounting portion 138 is greater than the thickness of the bus bar 108. With this structure, when the power storage module 100 comes into contact with a surrounding member, the bus bar 108 can be prevented from coming into contact with the surrounding member. Alternatively, the thickness of the bus bar 108 can be greater than the depth of the mounting portion 138. In this case, the portion of the bus bar 108 that protrudes from the mounting portion 138 can be covered with a cap (not shown) having an insulating property. The reinforcing member 128 is, for example, made of a resin having an insulating property. As the resin that constitutes the reinforcing member 128, a thermoplastic resin such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), Noryl (registered trademark) resin (modified PPE), or the like; carbon fiber reinforced plastic (CFRP); or the like can be used.

[0056] In the state in which the power storage devices 1 held by the holders 104 are aligned in the second direction C and the adjacent holders 104 are connected, the reinforcing members 128 are inserted into both sides of each holder 104 in the axial direction A. Further, the bus bars 108 are mounted to at least a portion of the mounting portions 138. The bus bar 108 is a band-shaped conductive member that extends in the first direction B, and the first electrode lead 8 and the second electrode lead 10 of each power storage device 1 are electrically connected to the bus bar 108. Thus, the plurality of electrode bodies 2 are electrically connected. For example, each electrode lead is joined to the bus bar 108 by a known joining process such as laser welding. By providing the reinforcing members 128 between the power storage devices 1 and the bus bar 108, the electrical connection of the power storage devices 1 to the bus bar 108 at portions other than the electrode leads can be suppressed.

[0057] In the present embodiment, the plurality of first electrode leads 8 protrude to the same side in each power storage device 1. Further, the adjacent two power storage devices 1 are set in a posture such that the first electrode leads 8 protrude to the same side. Thus, if each electrode lead is joined to the bus bar 108, all the electrode bodies 2 are connected in parallel with each other. Alternatively, the manner of electrical connection of each electrode body 2 is not particularly limited. For example, the first electrode lead 8 and the second electrode lead 10 can be alternately arranged side by side in each power storage device 1, and the adjacent first electrode lead 8 and second electrode lead 10 can be electrically connected. In other words, in each power storage device 1, the plurality of electrode bodies 2 can be connected in series. Further, the adjacent two power storage devices 1 can be connected in series. Further, all the electrode bodies 2 mounted to the power storage module 100 can be connected in series.

[0058] Further, the first electrode lead 8 and the second electrode lead 10 can also project toward the same side of each other in the axial direction A. Thus, by providing the bus bar 108 on only one side of the power storage module 100, the electrical connection of the electrode bodies 2 can be performed. Therefore, the assembly man-hours of the power storage module 100 can be reduced.

[0059] As described above, the power storage module 100 according to the present embodiment includes the power storage device 1, the holder 104 that holds the power storage device 1, and the reinforcing member 128 of the holder 104. The power storage device 1 includes the plurality of electrode bodies 2 that are cylindrical, and the film outer body 4 that includes the plurality of accommodation portions 12 that respectively surround the plurality of electrode bodies 2, and the sealing portion 14 that seals each of the accommodation portions 12 and links the plurality of accommodation portions 12 to each other. The holder 104 includes the side plate 112 that extends in the arrangement direction (the first direction B) of the plurality of electrode bodies 2, that is, the side plate 112 that includes the plurality of recessed portions 112a that are side by side in the first direction B and in which each of the accommodation portions 12 is fitted. The reinforcing member 128 extends in the first direction B and is side by side with the holder 104 in the axial direction A of the electrode bodies 2, and has the first groove portion 134 in which the side plate 112 is fitted on the side facing the holder 104.

[0060] The power storage device 1 is longer in the first direction B, and further, the film outer body 4 is flexible. Therefore, if the power storage device 1 is impacted from the outside or the like, it is easy to bend so that the central portion in the first direction B protrudes toward the second direction C with respect to both end portions. Further, since the power storage device 1 is longer in the first direction B, the side plate 112 is also longer in the first direction B. Further, from the viewpoint of lightening the power storage module 100 or the like, it is necessary to make the thickness of the holder 104 extremely thin. Therefore, it is difficult to make the holder 104 have rigidity that can sufficiently suppress the degree of bending of the power storage device 1 described above.

[0061] In this regard, by fitting the reinforcing member 128 to the end portion of the side plate 112, it is possible to increase the rigidity of the holder 104 against the bending described above. Therefore, it is possible to increase the holding strength of the power storage device 1. Further, it is possible to effectively reduce the stress that occurs in the holder 104, and it is possible to increase the rigidity of the power storage module 100.

[0062] Further, the present inventors have confirmed that, compared to a case where the thickness of the holder 104 is increased to increase the holding strength of the power storage device 1, the holding strength is increased by the reinforcing member 128 more capable of suppressing an increase in the weight of the power storage module 100. In other words, by increasing the rigidity of the holder 104 using the reinforcing member 128, compared to a case where the same rigidity is obtained by an increase in the thickness of the holder 104, it is more capable of suppressing an increase in the weight of the power storage module 100.

[0063] Further, the side plate 112 of the present embodiment has a plurality of recesses 112a, each of which accommodates each of the accommodation portions 12. Thus, the electricity storage device 1 can be held more stably. Therefore, the electricity storage device 1 and the bus bar 108 can be electrically connected more stably, and further, the electricity storage device 1 can be prevented from being damaged or the like more. Thus, the electricity generation performance and the safety performance of the electricity storage module 100 can be improved. Further, since the plurality of electrode bodies 2 are sealed by the pouch structure of the thin film outer packaging body 4, the electricity storage module 100 can be made lighter than when each of the electrode bodies 2 is sealed by an outer packaging can.

[0064] Further, the holder 104 of the present embodiment has a pair of protruding portions 114 protruding from both ends of the side plate 112 in the first direction B in a direction intersecting the arrangement direction and the axial direction A. Also, the reinforcing member 128 has a pair of second groove portions 136 into which the pair of protruding portions 114 are fitted on a surface facing the holder 104. Thus, the three sides on the same surface in the holder 104 can be fixed by the reinforcing member 128. Therefore, the rigidity of the holder 104 can be improved more, and the holding strength of the electricity storage device 1 can be improved more. Further, the reinforcing member 128 of the present embodiment is disposed on both sides of the holder 104 in the axial direction A. Thus, the holding strength of the electricity storage device 1 can be improved more.

[0065] Further, the first groove portion 134 and the second groove portion 136 of the present embodiment are connected to each other. With this structure, the corner portion of the side plate 112 and the protruding portion 114 in the holder 104 can be accommodated in the groove portion. Therefore, the holder 104 can be held more firmly.

[0066] Further, the reinforcing member 128 of the present embodiment has insulating properties, and has a mounting portion 138 of the bus bar 108 electrically connecting the plurality of electrode bodies 2. Thus, the reinforcement of the holder 104 and the insulation of the bus bar 108 can be achieved by one member. Therefore, the increase in the number of components of the electricity storage module 100 due to the provision of the reinforcing member 128 can be suppressed.

[0067] Further, the electricity storage module 100 of the present embodiment has a plurality of electricity storage devices 1. The side plate 112 is a wavy plate shape in which the concave and convex portions are repeated in the first direction B, and is sandwiched by two electricity storage devices 1. Each of the accommodation portions 12 of one of the electricity storage devices 1 is fitted in each of the recesses 112a when viewed from one main surface side, and each of the accommodation portions 12 of the other electricity storage device 1 is fitted in each of the convex portions 112b when viewed from the other main surface side. Thus, the stability of each of the electricity storage devices 1 in the electricity storage module 100 can be improved more.

[0068] Further, the thin film outer body 4 of the present embodiment is bent or curved between the adjacent housing portions 12 so as to extend in a zigzag shape. Thereby, it is possible to shorten the length of the power storage device 1 more than in the case where the thin film outer body 4 is not folded, without reducing the seal portion 14. As a result, it is possible to increase the number of electrode bodies 2 mounted to the power storage module 100, or to downsize the power storage module 100 without reducing the number of electrode bodies 2 mounted. In other words, by the present embodiment, it is possible to suppress a decrease in the sealing property of the electrode body 2 and to achieve an increase in the energy density of the power storage module 100.

[0069] The above describes the embodiments of the present disclosure in detail. The embodiments merely represent specific examples in implementing the present disclosure. The contents of the embodiments do not limit the technical scope of the present disclosure, and various design changes such as changes, additions, and deletions of structural elements can be made within the scope of the ideas defined in the claims. The new embodiments added by the design changes have the effects of the embodiments and the modified examples combined. In the embodiments, although the expressions such as "the present embodiment" and "in the present embodiment" are emphasized with respect to the contents to which such design changes can be made, the contents without such expressions also allow the design changes. Further, any combination of the structural elements included in the embodiments is also effective as a mode of the present disclosure. The hatching on the cross sections of the drawings is not the material of the object to which the hatching is added.

[0070] (Modified Example)

[0071] The present modified example has a structure common to the embodiments except for the shape of the reinforcing member 128. Hereinafter, the present modified example will be described focusing on the structure different from the embodiments, and the common structure will be omitted. Figure 8 is a perspective view of a part of the power storage module 100 to which the present modified example is applied. In addition, in Figure 8 , the illustration of the power storage device 1 is simplified. Further, the illustration of the bus bar 108 is omitted.

[0072] As shown in Figure 8 , the reinforcing member 128 provided in the power storage module 100 to which the present modified example is applied has a main body portion 140 and a pair of arm portions 142. The main body portion 140 corresponds to the reinforcing member 128 in the embodiments and is a flat bar shape, and extends in the first direction B at a position where the axis direction A overlaps with the side plate 112. On the side facing the holder 104, the first groove portion 134 and the second groove portion 136 are provided.

[0073] A pair of arm portions 142 protrude from both ends of the main body portion 140 in the first direction B toward the second direction C, and overlap the protruding portion 114 in the axial direction A. Therefore, the reinforcing member 128 has a substantially U-shaped form that is longer in the first direction B, as viewed in the axial direction A. Each second groove portion 136 extends from the main body portion 140 to the front end of each arm portion 142. Thereby, the contact area of the second groove portion 136 with the protruding portion 114 can be increased. As a result, the rigidity of the retainer 104 can be further improved, and thus the retention strength of the power storage device 1 can be further improved.

[0074] -Explanation of Symbols-

[0075] 1 power storage device, 2 electrode body, 4 film outer body, 12 accommodation portion, 14 sealing portion, 100 power storage module, 104 retainer, 108 bus bar, 112 side plate, 112a recessed portion, 112b protruding portion, 114 protruding portion, 128 reinforcing member, 134 first groove portion, 136 second groove portion, 138 mounting portion.

Claims

1. An electricity storage module comprising: an electricity storage device; a holder that holds the electricity storage device; and a reinforcing member of the holder, the electricity storage device having a plurality of electrode bodies that are cylindrical, and a thin film outer body that has a plurality of accommodation portions that respectively surround the plurality of electrode bodies, and a sealing portion that seals each of the accommodation portions and links the plurality of accommodation portions to each other, the holder having a side plate that extends in an arrangement direction that is perpendicular to an axial direction of the electrode bodies, the side plate having a plurality of recessed portions that are side by side in the arrangement direction and into which each of the accommodation portions is fitted, the reinforcing member extending in the arrangement direction and being side by side with the holder in the axial direction of the electrode bodies, a first groove portion of the reinforcing member having the side plate fitted into a surface of the reinforcing member that faces the holder, the holder having a pair of protruding portions that protrude from both ends of the side plate in the arrangement direction in a direction that intersects the arrangement direction and the axial direction, the reinforcing member having a second groove portion into which the pair of protruding portions are fitted in the surface of the reinforcing member that faces the holder.

2. The electricity storage module according to claim 1, wherein the first groove portion and the second groove portion are connected to each other.

3. The electricity storage module according to claim 1 or 2, wherein the reinforcing member is disposed on both sides of the holder in the axial direction.

4. The electricity storage module according to claim 1, wherein the reinforcing member is insulating, and the reinforcing member has a mounting portion of a bus bar that electrically connects the plurality of electrode bodies.

5. The electricity storage module according to claim 1, wherein the electricity storage module comprises a plurality of the electricity storage devices, the side plate is a wave-shaped plate that is repeatedly concave-convex in the arrangement direction, and the side plate is sandwiched by two of the electricity storage devices, each of the accommodation portions of one of the electricity storage devices is fitted into each of the recessed portions when viewed from one main surface side, and each of the accommodation portions of the other of the electricity storage devices is fitted into each of the convex portions when viewed from the other main surface side.

6. The electricity storage module according to claim 1, wherein the thin film outer body is bent or curved between adjacent ones of the accommodation portions so as to extend in a zigzag shape.

7. The electricity storage module according to claim 1, wherein the electricity storage module comprises a plurality of device units, and each of the plurality of device units comprises the electricity storage device, the holder, and the reinforcing member. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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