Energy storage module

Abstract

This electric power storage module is provided with: an array body having a plurality of electric power storage devices arrayed in a first direction; a pair of end plates which are disposed at respective ends of the array body so as to sandwich the array body; and a first restraint member and a second restraint member that restrain the array body in the first direction. The first restraint member comprises: a first body part which extends in the first direction; and a pair of first protrusions which protrude from respective ends of the first body part toward the side of the end plates and which are fixed to the respective end plates. The second restraint member comprises: a second body part which extends in the first direction; and a pair of second protrusions which protrude from respective ends of the second body part toward the side of the end plates and which are fixed to the respective end plates. At least a portion of the first protrusions and at least a portion of the second protrusions are configured to overlap one another in the first direction so as to form an overlapping part.

Description

Technical Field

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

Background Art

[0002] For example, as a power source that requires a high output voltage such as for vehicles, a power storage module in which a plurality of power storage devices (for example, batteries) are connected in series is known. Generally, a power storage module includes a plurality of power storage devices, a pair of end plates disposed at both ends in the arrangement direction of the power storage devices, and a restraint member (bind bar) that is stretched between the pair of end plates to restrain the plurality of batteries in the arrangement direction (for example, see Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, power storage devices expand due to various factors. In conventional power storage modules, the expansion of the power storage devices is suppressed by end plates and restraint members. However, in recent years, with the increase in the capacity of power storage devices, the amount of expansion of power storage devices has tended to increase. As the amount of expansion of the power storage device increases, the load on the restraint structure of the power storage device also increases.

[0005] The present disclosure has been made in view of such a situation, and one of its objects is to provide a technique for enhancing the strength of the restraint structure of a power storage device.

Means for Solving the Problems

[0006] One aspect of the present disclosure is a power storage module. This power storage module includes an array in which a plurality of power storage devices are arranged in a first direction, a pair of end plates disposed at both ends of the array in the first direction and sandwiching the array, and a first restraint member and a second restraint member that restrain the array in the first direction. The first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plates and fixed to each end plate. The second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plates and fixed to each end plate. At least a part of the first protruding portion and at least a part of the second protruding portion overlap each other in the first direction to form an overlapping portion.

[0007] Any combination of the above components, and those obtained by converting the expressions of the present disclosure among methods, apparatuses, systems, etc., are also valid as aspects of the present disclosure.

Advantages of the Invention

[0008] According to the present disclosure, the strength of the restraint structure of the power storage device can be increased.

Brief Description of the Drawings

[0009]

Fig. 1

Fig. 2

Fig. 3

Fig. 4

Fig. 5A

Fig. 5B

Fig. 6

Fig. 7

Fig. 8A

Fig. 8B

Mode for Carrying Out the Invention

[0010] Hereinafter, the present disclosure will be described with reference to the drawings based on preferred embodiments. The embodiments are illustrative rather than limiting the present disclosure, and all features and combinations thereof described in the embodiments are not necessarily essential to the present disclosure. The same or equivalent components, members, and processes shown in each drawing are denoted by the same reference numerals, and repeated explanations are omitted as appropriate. In addition, the scales and shapes of the respective parts shown in each figure are set for convenience in order to facilitate the explanation, and are not to be construed in a limited manner unless otherwise specified. Further, when terms such as "first" and "second" are used in this specification or claims, this term does not represent any order or importance unless otherwise specified, and is for distinguishing one configuration from another configuration. In addition, a part of the members that are not important in explaining the embodiments in each drawing is omitted from the display.

[0011] (Embodiment 1) FIG. 1 is a perspective view of the power storage module 1 according to Embodiment 1. FIG. 2 is an exploded perspective view of the power storage module 1. FIG. 3 is a perspective view of the power storage device 14 and the separator 16. The power storage module 1 includes an array body 2, a pair of end plates 4, a pair of first restraint members 6, a pair of second restraint members 8, a heat conduction member 10, and a cooling plate 12.

[0012] The array body 2 includes a plurality of power storage devices 14 and a plurality of separators 16. Each power storage device 14 is, for example, a rechargeable secondary battery such as a lithium-ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery, or a capacitor such as an electric double layer capacitor. The power storage device 14 of the present embodiment is a so-called rectangular battery and has a flat rectangular parallelepiped-shaped housing 18. The housing 18 is composed of an outer can 20 and a sealing plate 22.

[0013] The outer can 20 has a substantially rectangular opening on one side, and an electrode body, an electrolytic solution, etc. are accommodated in the outer can 20 through this opening. The outer can 20 has a bottom surface facing the opening and four side surfaces connecting the opening and the bottom surface. Two of the four side surfaces are a pair of long side surfaces connected to two opposite long sides of the opening. Each long side surface is the surface with the largest area among the surfaces of the outer can 20, that is, the main surface. The remaining two side surfaces excluding the two long side surfaces are a pair of short side surfaces connected to the short side of the opening of the outer can 20.

[0014] The outer can 20 may be covered with an insulating film (not shown) such as a shrink tube. By covering the surface of the outer can 20 with an insulating film, a short circuit between adjacent power storage devices 14 can be suppressed. Also, a short circuit between the power storage device 14 and each of the end plate 4, the first restraint member 6, and the second restraint member 8 can be suppressed. A sealing plate 22 that closes the opening and seals the outer can 20 is fitted into the opening of the outer can 20. The outer can 20 and the sealing plate 22 are conductors and are composed of a metal such as aluminum, iron, or stainless steel, for example. The outer can 20 and the sealing plate 22 are joined by, for example, laser, friction stir welding, brazing, etc. Alternatively, the outer can 20 and the sealing plate 22 are composed of an insulating resin.

[0015] A pair of output terminals 24 are arranged on the sealing plate 22. Specifically, a positive electrode terminal 24a is provided near one end in the longitudinal direction of the sealing plate 22, and a negative electrode terminal 24b is provided near the other end. Hereinafter, when it is not necessary to distinguish the polarities of the pair of output terminals 24, the positive electrode terminal 24a and the negative electrode terminal 24b are collectively referred to as the output terminal 24.

[0016] Each power storage device 14 has a first surface 14a and a second surface 14b facing each other, and a third surface 14c and a fourth surface 14d connecting the first surface 14a and the second surface 14b and facing each other. In the present embodiment, the sealing plate 22 constitutes the first surface 14a, and the bottom surface of the outer can 20 constitutes the second surface 14b. Also, a pair of short side surfaces of the outer can 20 constitute the third surface 14c and the fourth surface 14d. Further, a pair of long side surfaces of the outer can 20 constitute the long side surfaces of the power storage device 14. Each power storage device 14 is arranged such that each first surface 14a faces the same direction and each third surface 14c faces the same direction. Therefore, each second surface 14b also faces the same direction, and each fourth surface 14d also faces the same direction.

[0017] In the description of the present embodiment, for convenience, the first surface 14a side of the power storage device 14 is set as the vertically upward direction, and the second surface 14b side of the power storage device 14 is set as the vertically downward direction. Also, in the array 2, the surface on the first surface 14a side of the power storage device 14 is set as the upper surface of the array 2, the surface on the second surface 14b side of the power storage device 14 is set as the lower surface of the array 2, and the surfaces on the third surface 14c side and the fourth surface 14d side of the power storage device 14 are set as the side surfaces of the array 2. Note that the pair of output terminals 24 may not be arranged on the first surface 14a. For example, the pair of output terminals 24 may be arranged on the third surface 14c. Also, the two output terminals 24 may be provided on different surfaces among the first surface 14a to the fourth surface 14d.

[0018] These directions and positions are defined for convenience. Therefore, for example, in the present disclosure, the portion defined as the upper surface does not necessarily mean that it is located above the portion defined as the lower surface. Thus, the first surface 14a is not necessarily located above the second surface 14b. Also, hereinafter, the direction in which a plurality of power storage devices 14 are arranged (stacked) is defined as the first direction A, the direction in which the first surface 14a and the second surface 14b are arranged side by side is defined as the second direction B, and the direction in which the third surface 14c and the fourth surface 14d are arranged side by side is defined as the third direction C. The first direction A, the second direction B, and the third direction C are directions orthogonal to each other. As an example, the first surface 14a to the fourth surface 14d all extend parallel to the first direction A.

[0019] The power storage device 14 has a valve portion 26 on the first surface 14a. Note that the valve portion 26 may be omitted. The valve portion 26 is disposed between the pair of output terminals 24. The valve portion 26 is configured to open when the internal pressure of the housing 18 rises to a predetermined value or more, and release the gas inside the housing 18. The valve portion 26 is composed of, for example, a thin portion that is thinner than other portions provided on a part of the sealing plate 22, and a linear groove formed on the surface of this thin portion. In this configuration, when the internal pressure of the housing 18 rises, the thin portion tears starting from the groove, and the valve portion 26 opens.

[0020] The plurality of power storage devices 14 are arranged in the first direction A at a predetermined interval such that the long side surfaces of adjacent power storage devices 14 face each other. Two adjacent power storage devices 14 are arranged such that the positive electrode terminal 24a of one power storage device 14 and the negative electrode terminal 24b of the other power storage device 14 are adjacent to each other. The positive electrode terminal 24a and the negative electrode terminal 24b are connected in series via a bus bar (not shown). Note that the output terminals 24 of the same polarity in a plurality of adjacent power storage devices 14 may be connected in parallel by a bus bar to form a power storage device block, and the power storage device blocks may be connected in series.

[0021] The separator 16, also called an insulating spacer, is disposed between the opposing long side surfaces of two adjacent power storage devices 14 to electrically insulate the two power storage devices 14 from each other. The separator 16 is composed of, for example, a resin having insulating properties. Examples of the resin constituting the separator 16 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE). The plurality of power storage devices 14 and the plurality of separators 16 are alternately laminated. Further, the separator 16 is also disposed between the power storage device 14 and each end plate 4. Thereby, the power storage device 14 and each end plate 4 are insulated from each other.

[0022] Each separator 16 has a main body portion 28 and a wall portion 30. The main body portion 28 is flat and is interposed between the long side surfaces of two adjacent power storage devices 14. The wall portion 30 extends in the first direction A from two side edge portions aligned in the third direction C of the main body portion 28, and mainly covers the third surface 14c and the fourth surface 14d of the power storage device 14. In the present embodiment, the main body portion 28 and the wall portion 30 are integrally formed.

[0023] A pair of end plates 4 are arranged at both ends of the array 2 in the first direction A. The array 2 obtained by alternately arranging a plurality of power storage devices 14 and a plurality of separators 16 is sandwiched in the first direction A by a pair of end plates 4. Each end plate 4 is made of, for example, a metal plate or a resin plate and is rectangular when viewed from the first direction A. Examples of the metal used for each end plate 4 include aluminum, aluminum alloy, and steel. Examples of the resin used for each end plate 4 include fiber reinforced plastic (FRP). Fiber reinforced plastic includes carbon fiber reinforced plastic and glass fiber reinforced plastic. Each end plate 4 is provided with a screw hole 34 into which a screw 32 as a fastening member is screwed. The structure of the end plate 4 will be described in detail later.

[0024] A pair of first restraint members 6 and a pair of second restraint members 8 are also called binder bars. Each first restraint member 6 and each second restraint member 8 extend in the first direction A and restrain the array 2 in the first direction A. One of the pair of first restraint members 6 faces the first surface 14a of each power storage device 14, and the other faces the second surface 14b of each power storage device 14. That is, the pair of first restraint members 6 face each other in the second direction B with the array 2 interposed therebetween. One of the pair of second restraint members 8 faces the third surface 14c of each power storage device 14, and the other faces the fourth surface 14d of each power storage device 14. That is, the pair of second restraint members 8 face each other in the third direction C with the array 2 interposed therebetween.

[0025] Each first restraining member 6 has a first main body portion 36 and a pair of first projecting portions 38. The first main body portion 36 is a rectangular plate-like body extending in the first direction A. The first main body portion 36 extends parallel to the first surface 14a or the second surface 14b of each power storage device 14. When viewed from the second direction B, the contour of the first main body portion 36 is substantially the same as the contour of the aggregate composed of the array body 2 and the pair of end plates 4. The pair of first projecting portions 38 project from both ends of the first main body portion 36 in the first direction A toward the end plate 4 side, in other words, toward the opposing first restraining member 6 side, and overlap with each end plate 4 in the first direction A. The pair of first projecting portions 38 face each other in the first direction A with the array body 2 interposed therebetween. Each first projecting portion 38 is provided with a through hole 40 through which a screw 32 is inserted.

[0026] The pair of first restraining members 6 has a hole portion 42. For example, the hole portion 42 is configured by a through hole penetrating the first main body portion 36 in the second direction B. Note that the hole portion 42 may be configured by a recess recessed in the second direction B. By providing each first restraining member 6 with the hole portion 42, the weight of each first restraining member 6 can be reduced. Further, in the present embodiment, each first restraining member 6 has three hole portions 42. Each hole portion 42 extends in the first direction A and overlaps with a plurality of power storage devices 14. The output terminals 24 and the valve portions 26 of each power storage device 14 are exposed to the outside through each hole portion 42.

[0027] Each second restraint member 8 has a second main body portion 44 and a pair of second protruding portions 46. The second main body portion 44 is a rectangular plate-like body extending in the first direction A. The second main body portion 44 extends parallel to the third surface 14c or the fourth surface 14d of each power storage device 14. When viewed from the third direction C, the contour of the second main body portion 44 is substantially the same as the contour of the aggregate composed of the array body 2 and the pair of end plates 4. The pair of second protruding portions 46 protrude from both ends of the second main body portion 44 in the first direction A toward the end plate 4 side, in other words, toward the opposing second restraint member 8 side, and overlap each end plate 4 in the first direction A. The pair of second protruding portions 46 face each other in the first direction A with the array body 2 interposed therebetween. Each second protruding portion 46 is provided with a through hole 48 through which the screw 32 is inserted. Although the second restraint member 8 shown in FIGS. 1 and 2 does not have the hole portion 42, the present invention is not limited to this, and the second restraint member 8 may also be provided with the hole portion 42. In this case, for example, the hole portion 42 is provided in the second main body portion 44.

[0028] For example, each first restraint member 6 and each second restraint member 8 may be formed of a single plate material. The main body portion and the pair of protruding portions can be formed by bending both ends of a metal plate. In this case, the portion from the bending position to the tip becomes the protruding portion, and the remaining portion becomes the main body portion. Note that the restraint member may be made of resin as long as a predetermined rigidity or more can be obtained. Further, the main body portion and the protruding portion, which are separate from each other, may be joined to form the restraint member. Examples of the metal used for the restraint member include aluminum, aluminum alloy, and steel. Examples of the resin used for the restraint member include fiber-reinforced plastics (FRP) including carbon fiber-reinforced plastics and glass fiber-reinforced plastics.

[0029] The power storage module 1 is assembled as follows, for example. That is, a plurality of power storage devices 14 and a plurality of separators 16 are alternately arranged to form an array body 2, and the array body 2 is sandwiched in the first direction A by a pair of end plates 4. After the array body 2 and the pair of end plates 4 are sandwiched in the third direction C by a pair of second restraint members 8, they are sandwiched in the second direction B by a pair of first restraint members 6. Each first restraint member 6 is aligned so that the through hole 40 overlaps with the screw hole 34 of the end plate 4. Each second restraint member 8 is aligned so that the through hole 48 overlaps with the screw hole 34 of the end plate 4. Also, a part of the through hole 40 and the through hole 48 overlap with each other. In this state, the screw 32 is passed through the through holes 40, 48 and the screw hole 34. Specifically, the screw 32 is inserted into the through holes 40, 48 and screwed into the screw hole 34. As a result, the first protrusion 38 and the second protrusion 46 are fastened and fixed to the end plate 4.

[0030] By fastening each first restraint member 6 and each second restraint member 8 to the pair of end plates 4, the plurality of power storage devices 14 are restrained in the first direction A. Therefore, an end plate 4, a first restraint member 6, and a second restraint member 8 constitute a restraint structure for the power storage device 14. Note that the first protrusion 38 and the end plate 4, and the second protrusion 46 and the end plate 4 may be fixed by welding or the like. Also, the surface of each restraint member facing the array body 2 may be covered with an insulating sheet (not shown).

[0031] As an example, after these positionings are completed, a bus bar is attached to the output terminal 24 of each power storage device 14, and the output terminals 24 of the plurality of power storage devices 14 are electrically connected to each other. For example, the bus bar is fixed to the output terminal 24 by welding. Thereafter, the upper surface of the array body 2 is covered with a cover member (not shown). The cover member prevents contact of condensed water, dust, etc. with the output terminal 24, the bus bar, the valve portion 26, etc. The cover member is made of, for example, an insulating resin and can be fixed to the upper surface of the array body 2 by a well-known fixing structure (not shown) including screws and a well-known locking mechanism.

[0032] The heat conduction member 10 is housed in the hole 42 of the first restraint member 6 facing the second surface 14b of each power storage device 14 and is in heat exchange contact with each second surface 14b. The heat conduction member 10 is made of a material with a higher thermal conductivity than air. Preferably, the heat conduction member 10 has insulation properties. Also preferably, the heat conduction member 10 has flexibility. As the heat conduction member 10, a known resin sheet having good thermal conductivity such as acrylic rubber or silicone rubber, or a known cooling gel can be used.

[0033] The cooling plate 12 is a mechanism for cooling a plurality of power storage devices 14. The cooling plate 12 is made of a material having high thermal conductivity such as aluminum. As an example, the array body 2 has its lower surface side facing the cooling plate 12 and is placed on the main surface of the cooling plate 12 via the first restraint member 6. In this state, the cooling plate 12 is in heat exchange contact with the heat conduction member 10. Each power storage device 14 is cooled by exchanging heat with the cooling plate 12 via the heat conduction member 10. Note that the first restraint member 6 may also be in heat exchange contact with the cooling plate 12. In this case, each power storage device 14 can exchange heat with the cooling plate 12 via the heat conduction member 10 and the first restraint member 6. A refrigerant pipe (not shown) through which a refrigerant such as water or ethylene glycol flows may be provided inside the cooling plate 12.

[0034] Preferably, the heat conduction member 10 is sandwiched between the array body 2 and the cooling plate 12 and elastically deformed to fill the gap between the second surface 14b of each power storage device 14 and the cooling plate 12. Thereby, the cooling efficiency of each power storage device 14 can be enhanced.

[0035] Subsequently, the restraint structure of the power storage device 14 will be described in detail. FIG. 4 is a side view of the power storage module 1 as viewed from the first direction A. FIG. 5A is a perspective view of a part of the end plate 4. FIG. 5B is a perspective view of a part of each of the end plate 4, the first restraint member 6, and the second restraint member 8. Note that in FIG. 4, the illustration of the screw 32 is omitted. Also, in FIG. 5B, the illustration of the hole 42 is omitted.

[0036] As shown in FIG. 4, in a state where the first restraint member 6 and the second restraint member 8 are fastened to the end plate 4, at least a part of each first protrusion 38 and at least a part of each second protrusion 46 overlap each other in the first direction A. By the overlap of the first protrusion 38 and the second protrusion 46, an overlapping portion 50 is formed on the main surface of the end plate 4. In the present embodiment, both ends of each first protrusion 38 in the third direction C and both ends of each second protrusion 46 in the second direction B overlap each other. Therefore, when viewed from the first direction A, overlapping portions 50 are formed at the four corners of the end plate 4.

[0037] In the overlapping portion 50, the second protrusion 46 is located closer to the end plate 4 than the first protrusion 38. That is, in the first direction A, the second protrusion 46 is located on the inner side and the first protrusion 38 is located on the outer side. Also, as shown in FIGS. 5A and 5B, the end plate 4 has recesses 52 at positions overlapping the second protrusions 46. The recesses 52 have a shape recessed in the first direction A. The recesses 52 are arranged at both ends in the third direction C of the main surface 54 facing away from the array body 2 of the end plate 4. Hereinafter, as appropriate, the region of the main surface 54 where the recesses 52 are not provided is referred to as the remainder of the main surface 54. Each second protrusion 46 fits (is received) into each recess 52. Thereby, the step between the remainder of the main surface 54 and the surface of the second protrusion 46 (the end face in the first direction A) is reduced. That is, in the first direction A, the protruding amount of the second protrusion 46 with respect to the remainder of the main surface 54 is reduced. The depth of the recess 52 (the dimension in the first direction A) may be equal to the thickness of the second protrusion 46 (the dimension in the first direction A). Thereby, the remainder of the main surface 54 and the surface of the second protrusion 46 can be flush. That is, the protruding amount of the second protrusion 46 described above can be zero.

[0038] Note that the recess 52 may not be provided. When the recess 52 is not provided, the region excluding the region included in the overlapping portion 50 in the first protruding portion 38 (that is, the region not constituting the overlapping portion 50) may be separated from the main surface 54 of the end plate 4 due to the thickness of the second protruding portion 46. In this case, the first protruding portion 38 may be bent so that the region protrudes toward the main surface 54. Alternatively, the region may be thickened so as to protrude toward the main surface 54. Further, the bottom surface of the recess 52 can also be regarded as the main surface 54 of the end plate 4. In this case, the remaining portion of the main surface 54 in the present embodiment can be interpreted as a rib portion (protruding portion) provided on the main surface 54. In this interpretation, the overlapping portion 50 overlaps with the region excluding the rib portion of the main surface 54. Further, the fastening portion 56 described later overlaps with the rib portion and is fastened to the rib portion.

[0039] The first protruding portion 38 extends from the surface of one second protruding portion 46, passes through the remaining portion of the main surface 54, and reaches the surface of the other second protruding portion 46. Since each second protruding portion 46 is fitted into the recess 52, the first protruding portion 38 can contact the remaining portion of the main surface 54 with a smaller gap or without a gap in a state of contacting each second protruding portion 46.

[0040] The first protruding portion 38 has a fastening portion 56 that is directly fastened to the end plate 4 in a region excluding the region included in the overlapping portion 50. The first protruding portion 38 of the present embodiment has the fastening portion 56 at the central portion (the region sandwiched between both end portions) in the third direction C. The fastening portion 56 overlaps with the remaining portion of the main surface 54 without passing through the second protruding portion 46. Further, the fastening portion 56 has a through hole 40, and the remaining portion of the main surface 54 has a screw hole 34. The through hole 40 of the fastening portion 56 and the screw hole 34 of the main surface 54 overlap with each other, and the fastening portion 56 is directly fastened to the end plate 4 by inserting a screw 32 therethrough. Note that, in the end plate 4 having no recess 52, the second protruding portion 46 contacts the main surface 54 of the end plate 4, and the fastening portion 56 may be separated from the main surface 54. In this case, a spacer (not shown) may be interposed between the fastening portion 56 or its periphery and the main surface 54 to fasten the fastening portion 56 to the end plate 4.

[0041] Regarding the positional relationship between the second protruding portion 46 and the end plate 4 in the second direction B, both ends of the second protruding portion 46 are located closer to the center side of the power storage module 1 in the second direction B than both ends of the end plate 4. Thereby, when assembling the first restraining member 6 to the end plate 4, it is possible to suppress interference of the second protruding portion 46.

[0042] As described above, the power storage module 1 according to the present embodiment includes an array body 2 in which a plurality of power storage devices 14 are arranged in the first direction A, a pair of end plates 4 disposed at both ends of the array body 2 in the first direction A and sandwiching the array body 2, and a first restraining member 6 and a second restraining member 8 that restrain the array body 2 in the first direction A. The first restraining member 6 has a first main body portion 36 extending in the first direction A and a pair of first protruding portions 38 protruding from both ends of the first main body portion 36 in the first direction A toward the end plate 4 and fixed to each end plate 4. The second restraining member 8 has a second main body portion 44 extending in the first direction A and a pair of second protruding portions 46 protruding from both ends of the second main body portion 44 in the first direction A toward the end plate 4 and fixed to each end plate 4. And at least a part of the first protruding portion 38 and at least a part of the second protruding portion 46 overlap each other in the first direction A to form an overlapping portion 50.

[0043] Normally, the protruding portions of the restraining member are installed so as to be within the extending range of the end plate 4. On the other hand, in order to cope with an increase in the expansion amount of the power storage device 14, it is conceivable to arrange restraining members on three or more surfaces of the array body 2 to restrain the array body 2 with a stronger force. Also, it is conceivable to increase the size of each restraining member to enhance the restraining force of the array body 2 that each individual restraining member has. In this case, the protruding portions of the respective restraining members approach each other. Therefore, in order to avoid interference between the protruding portions, it is necessary to make the size of each protruding portion smaller than the size allowable from the viewpoint of the size of the end plate 4. However, if the protruding portion is made small, the strength of the protruding portion decreases accordingly, and the strength of the restraining structure of the power storage device 14 may decrease.

[0044] In contrast, in the present embodiment, the overlap between the first protruding portion 38 and the second protruding portion 46 is allowed. Therefore, each protruding portion can be made larger compared to the case where the protruding portions are designed so as not to overlap each other. As a result, the strength of each protruding portion can be increased, and thus the strength of the restraint structure of the power storage device 14 can be increased. Further, by overlapping the protruding portions to form the overlapping portion 50, the thickness of the restraint structure can be increased. This can also increase the strength of the restraint structure. Therefore, it is possible to cope with an increase in the expansion amount of the power storage device 14. Further, since the protruding portions are overlapped to give the restraint structure thickness, it is possible to suppress the difficulty of processing the restraint member compared to the case where the thickness of the restraint member itself is increased.

[0045] Further, in the present embodiment, in the overlapping portion 50, the second protruding portion 46 is located closer to the end plate 4 side than the first protruding portion 38. And the end plate 4 has a concave portion 52 that is recessed in the first direction A and into which the second protruding portion 46 fits at a position overlapping the second protruding portion 46. Thereby, the gap between the remaining portion of the main surface 54 of the end plate 4 and the first protruding portion 38 can be reduced. As a result, the restraining force of the array body 2 included in the first restraining member 6 can be more effectively exerted.

[0046] Further, the first protruding portion 38 of the present embodiment has a fastening portion 56 that is directly fastened to the end plate 4 in a region excluding the region included in the overlapping portion 50. By fastening the fastening portion 56 to the end plate 4 in a state where the gap between the end plate 4 and the first restraining member 6 is reduced, the first restraining member 6 can be more firmly fastened to the end plate 4. As a result, the strength of the restraint structure of the power storage device 14 can be further increased.

[0047] In addition, each power storage device 14 of the present embodiment has a first surface 14a and a second surface 14b facing each other, and a third surface 14c and a fourth surface 14d connecting the first surface 14a and the second surface 14b and facing each other. And the power storage module 1 has a pair of first restraint members 6 facing the first surface 14a and the second surface 14b, and a pair of second restraint members 8 facing the third surface 14c and the fourth surface 14d. In this way, by providing restraint members on the four surfaces of the array body 2, the strength of the restraint structure of the power storage device 14 can be further increased. Note that only one of the first restraint member 6 or the second restraint member 8 may be provided. That is, restraint members may be provided on three surfaces of the array body 2.

[0048] In the present embodiment, in the overlapping portion 50, the protruding portion (second protruding portion 46) of the restraint member covering the short side surfaces (third surface 14c and fourth surface 14d) of the power storage device 14 is located closer to the end plate 4 side than the protruding portion (first protruding portion 38) of the restraint member covering the upper surface (first surface 14a) and the lower surface (second surface 14b) of the power storage device 14. However, it is not limited to this structure, and the protruding portion of the restraint member covering the upper and lower surfaces of the power storage device 14 may be located closer to the end plate 4 side than the protruding portion of the restraint member covering the short side surfaces of the power storage device 14. In this case, the short side surfaces of the power storage device 14 become the first surface 14a and the second surface 14b, the upper surface becomes the third surface 14c, the lower surface becomes the fourth surface 14d, the pair of restraint members facing each other in the third direction C becomes the first restraint member 6, and the pair of restraint members facing each other in the second direction B becomes the second restraint member 8.

[0049] (Embodiment 2) Embodiment 2 has the same configuration as Embodiment 1 except for the restraint structure of the power storage device 14. Hereinafter, the configuration different from that of Embodiment 1 in this embodiment will be mainly described, and the common configuration will be briefly described or the description will be omitted. FIG. 6 is a perspective view of the end plate 4, the first restraint member 6, and the second restraint member 8 included in the power storage module 1 according to Embodiment 2. FIG. 7 is a side view of the power storage module 1 viewed from the first direction A. FIG. 8A is a perspective view of a part of the end plate 4. FIG. 8B is a perspective view of a part of each of the end plate 4, the first restraint member 6, and the second restraint member 8. In FIG. 6, only a part of one end plate 4 and each restraint member is shown.

[0050] The power storage module 1 according to this embodiment includes an array 2 (see FIG. 2) in which a plurality of power storage devices 14 are arranged in the first direction A, a pair of end plates 4 disposed at both ends of the array 2 in the first direction A and sandwiching the array 2, and a first restraint member 6 and a second restraint member 8 extending in the first direction A and restraining the array 2 in the first direction A. The first restraint member 6 has a first main body portion 36 and a pair of first protruding portions 38. A through hole 40 is provided in each first protruding portion 38. The second restraint member 8 has a second main body portion 44 and a pair of second protruding portions 46. A through hole 48 is provided in each second protruding portion 46.

[0051] The first restraint member 6 and the second restraint member 8 of this embodiment are arranged side by side so as to face the first surface 14a (see FIG. 2) of each power storage device 14. Further, the first restraint member 6 and the second restraint member 8 are arranged side by side so as to face the second surface 14b (see FIG. 2) of each power storage device 14. As an example, the power storage module 1 has two first restraint members 6 and four second restraint members 8. One first restraint member 6 and two second restraint members 8 are arranged on each of the upper surface side and the lower surface side of the array 2. On each surface of the array 2, the second restraint member 8, the first restraint member 6, and the second restraint member 8 are arranged in this order in the third direction C.

[0052] In a state where each first restraint member 6 and each second restraint member 8 are fastened to the end plate 4, at least a part of each first protrusion 38 and at least a part of each second protrusion 46 overlap each other in the first direction A. By the overlapping of the first protrusion 38 and the second protrusion 46, an overlapping portion 50 is formed on the main surface of the end plate 4. In the present embodiment, both ends of each first main body portion 36 in the third direction C and the end portion of each second protrusion 46 on the side of the first main body portion 36 overlap each other. Therefore, when viewed from the first direction A, two overlapping portions 50 are formed above and below the central portion of the end plate 4 in the third direction C.

[0053] In the overlapping portion 50, the second protrusion 46 is located closer to the end plate 4 than the first protrusion 38. Further, as shown in FIGS. 8A and 8B, the end plate 4 has a recess 52 at a position overlapping the second protrusion 46. The recess 52 has a shape recessed in the first direction A. The recess 52 is arranged in a region excluding the central portion in the third direction C on the main surface 54 facing the side opposite to the array body 2 in the end plate 4. Each second protrusion 46 fits into each recess 52. Thereby, the step between the remaining portion of the main surface 54 and the surface of the second protrusion 46 is reduced. The remaining portion of the main surface 54 and the surface of the second protrusion 46 may be flush. Thereby, the first protrusion 38 can abut against each second protrusion 46 without a gap, and can also abut against the remaining portion of the main surface 54 with a smaller gap or without a gap.

[0054] In addition, when the first protrusion 38 between a pair of second protrusions 46 in the third direction C is arranged inside in the first direction A than each second protrusion 46, the recess 52 may be provided at the central portion in the third direction C. For example, the recess 52 is provided at a position overlapping the first protrusion 38. Further, the recess 52 does not have to extend to both ends in the third direction C as shown in FIG. 7. Further, the recess 52 does not have to extend to the central portion in the second direction B. For example, the recess 52 may be provided only in a region overlapping each second protrusion 46.

[0055] The first protrusion 38 has a fastening portion 56 that is directly fastened to the end plate 4 in a region excluding the region included in the overlapping portion 50. The first protrusion 38 of the present embodiment has the fastening portion 56 at the central portion in the third direction C. The fastening portion 56 overlaps the remaining portion of the main surface 54 without passing through the second protrusion 46. Then, by inserting the screw 32 through the through hole 40 and the screw hole 34, the fastening portion 56 is directly fastened to the end plate 4.

[0056] Also, a first region 58 continuous from the overlapping portion 50 in the first main body portion 36 and a second region 60 continuous from the overlapping portion 50 in the second main body portion 44 overlap each other in the second direction B. Thereby, the bent portion connecting the first protrusion 38 and the first main body portion 36 and the bent portion connecting the second main body portion 44 and the second protrusion 46 overlap each other.

[0057] As an example, the end plate 4 has a recess 62 at a position overlapping the second main body portion 44. The recess 62 is provided on the end surface in the second direction B orthogonal to the first direction A and has a shape recessed in the second direction B. The second main body portion 44, particularly the second region 60 of the second main body portion 44, fits (is accommodated) in the recess 62. Thereby, the step between the upper surface or the lower surface of the end plate 4 and the surface of the second main body portion 44 is reduced. The depth of the recess 62 (the size in the second direction B) may be equal to the thickness of the second main body portion 44 (the size in the second direction B). Thereby, the upper surface or the lower surface of the end plate 4 and the surface of the second main body portion 44 can be flush. Note that the recess 62 may be omitted.

[0058] The first main body portion 36 extends from the surface of one second main body portion 44 to the surface of the other second main body portion 44 via the upper surface or the lower surface of the end plate 4. Since each second main body portion 44 is fitted into the recess 62, the first protrusion 38 can abut against the upper surface or the lower surface of the end plate 4 with a smaller gap or without a gap in a state of abutting against each second main body portion 44.

[0059] As described above, in the power storage module 1 according to the present embodiment, the first restraint member 6 and the second restraint member 8 are arranged side by side so as to face the first surface 14a of each power storage device 14. In this way, by arranging a plurality of restraint members with respect to one surface of the array body 2, even if the array body 2 becomes larger and the installation surface of the restraint members expands, it is possible to suppress the enlargement of each individual restraint member. As a result, it is possible to suppress the difficulty of processing the restraint members.

[0060] Further, in the present embodiment, a first region 58 continuous from the overlapping portion 50 in the first main body portion 36 and a second region 60 continuous from the overlapping portion 50 in the second main body portion 44 overlap each other. For this reason, the bent portion connecting the first protruding portion 38 and the first main body portion 36 and the bent portion connecting the second main body portion 44 and the second protruding portion 46 overlap each other. When the power storage device 14 expands, stress tends to concentrate on the bent portions of each restraint member. Therefore, each restraint member is likely to be damaged at the bent portion. On the other hand, by overlapping the bent portions of each restraint member, it is possible to suppress the bent portion from being damaged. Therefore, the strength of the restraint structure of the power storage device 14 can be increased.

[0061] Note that, by forming the overlapping portion 50, in other words, by allowing the first protruding portion 38 and the second protruding portion 46 to overlap, a wider range of the edge portion of the end plate 4 can be covered by the bent portion of any one of the restraint members. Thereby, even when the bent portion of the first restraint member 6 and the bent portion of the second restraint member 8 do not overlap, the strength of the restraint structure can be increased. For example, in the third direction C, each protruding portion may be larger than each main body portion. That is, each restraint member may have an end portion in the first direction A in a T shape. Further, in the present embodiment, a restraint member may be provided at a position facing the side surface of the array body 2.

[0062] The embodiments of the present disclosure have been described in detail above. The above-described embodiments are merely specific examples for implementing the present disclosure. The content of the embodiments does not limit the technical scope of the present disclosure, and many design changes such as component changes, additions, deletions, etc. are possible without departing from the inventive concept defined in the claims. The new embodiments with design changes have the effects of the combined embodiments and deformations respectively. In the above-described embodiments, with regard to the content for which such design changes are possible, notations such as "in the present embodiment" and "in the present embodiment" are added for emphasis, but design changes are also allowed for the content without such notations. Also, any combination of the components included in each embodiment is effective as an aspect of the present disclosure. The hatching attached to the cross-section of the drawing does not limit the material of the hatched object.

[0063] In each of the above-described embodiments, the arrangement of the first protrusion 38 and the second protrusion 46, particularly, the positional relationship of the first protrusion 38 and the second protrusion 46 in the first direction A in the overlapping portion 50, may be the same or different between one end plate 4 side and the other end plate 4 side. If the positional relationship of the first protrusion 38 and the second protrusion 46 is made the same on both sides of the pair of end plates 4, the design of both ends of the power storage module 1 in the first direction A is likely to be standardized. However, in this case, the restraining member in which the protrusions on both sides are arranged inside is likely to be shorter than the restraining member in which the protrusions on both sides are arranged outside. That is, two types of restraining members with different dimensions may be required. On the other hand, if the positional relationship of the first protrusion 38 and the second protrusion 46 is reversed between one end plate 4 side and the other end plate 4 side, the dimensions of the first restraining member 6 and the second restraining member 8 in the first direction A are likely to be standardized.

Explanation of Reference Numerals

[0064] 1 Battery module, 2 Array body, 4 End plate, 6 First restraint member, 8 Second restraint member, 14 Energy storage device, 36 First main body portion, 38 First protruding portion, 44 Second main body portion, 46 Second protruding portion, 50 Overlapping portion, 52 Recess, 56 Fastening portion, 58 First region, 60 Second region.

Claims

1. An array body in which a plurality of power storage devices are arranged in a first direction; A pair of end plates disposed at both ends of the array body in the first direction and sandwiching the array body; A first restraint member and a second restraint member that restrain the array body in the first direction, and the first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plate side and fixed to each end plate; the second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plate side and fixed to each end plate; at least a part of the first protruding portion and at least a part of the second protruding portion form an overlapping portion by overlapping each other in the first direction; in the overlapping portion, the second protruding portion is located closer to the end plate side than the first protruding portion; the end plate has a recess that is recessed in the first direction at a position overlapping the second protruding portion and into which the second protruding portion fits; A power storage module.

2. At least a part of the first protruding portion and at least a part of the second protruding portion constituting the overlapping portion each have a through hole; the end plate has a screw hole; the through hole of the first protruding portion, the through hole of the second protruding portion, and the screw hole overlap in the first direction, and a fastening member is passed therethrough to fasten and fix the first restraint member, the second restraint member, and the end plate. The power storage module according to Claim 1.

3. An array body in which a plurality of power storage devices are arranged in a first direction; A pair of end plates disposed at both ends of the array body in the first direction and sandwiching the array body; A first restraint member and a second restraint member that restrain the array body in the first direction, and the first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plate side and fixed to each end plate; the second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plate side and fixed to each end plate; At least a part of the first protruding portion and at least a part of the second protruding portion overlap each other in the first direction to form an overlapping portion. The first protruding portion has a fastening portion fastened to the end plate in a region excluding the region included in the overlapping portion. Power storage module.

4. An array in which a plurality of power storage devices are arranged in a first direction, A pair of end plates disposed at both ends of the array in the first direction and sandwiching the array, A first restraint member and a second restraint member for restraining the array in the first direction, The first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plate side and fixed to each end plate. The second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plate side and fixed to each end plate. At least a part of the first protruding portion and at least a part of the second protruding portion overlap each other in the first direction to form an overlapping portion. The first protruding portion has a fastening portion fastened to the end plate in a region excluding the region included in the overlapping portion. The end plate has a rib portion on a main surface facing the side opposite to the array. The overlapping portion overlaps a region excluding the rib portion on the main surface. The fastening portion overlaps the rib portion and is fastened to the rib portion. Power storage module.

5. An array in which a plurality of power storage devices are arranged in a first direction, A pair of end plates disposed at both ends of the array in the first direction and sandwiching the array, A first restraint member and a second restraint member for restraining the array in the first direction, The first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plate side and fixed to each end plate. The second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plate side and fixed to each end plate. At least a part of the first protruding portion and at least a part of the second protruding portion overlap each other in the first direction to form an overlapping portion. Each power storage device has a first surface and a second surface facing each other, and a third surface and a fourth surface connecting the first surface and the second surface and facing each other. The first surface, the second surface, the third surface, and the fourth surface extend parallel to the first direction. This power storage module has a pair of the first restraint members facing the first surface and the second surface, and a pair of the second restraint members facing the third surface and the fourth surface. Power storage module. **Claim 6**: An array in which a plurality of power storage devices are arranged in a first direction, a pair of end plates disposed at both ends of the array in the first direction and sandwiching the array, a first restraint member and a second restraint member for restraining the array in the first direction. The first restraint member has a first main body portion extending in the first direction, and a pair of first protruding portions protruding from both ends of the first main body portion in the first direction toward the end plate side and fixed to each end plate. The second restraint member has a second main body portion extending in the first direction, and a pair of second protruding portions protruding from both ends of the second main body portion in the first direction toward the end plate side and fixed to each end plate. At least a part of the first protruding portion and at least a part of the second protruding portion overlap each other in the first direction to form an overlapping portion. Each power storage device has a first surface extending parallel to the first direction. The first restraint member and the second restraint member are arranged side by side so as to face the first surface. A first region continuous from the overlapping portion in the first main body portion and a second region continuous from the overlapping portion in the second main body portion overlap each other. Power storage module. **Claim 7** The end plate has a recess in an end face in a second direction orthogonal to the first direction. The second region is accommodated in the recess. The power storage module according to claim 6.

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