Energy Storage Module

Abstract

To improve reliability of a power storage module.SOLUTION: A power storage module comprises: a first power storage device 2a and a second power storage device 2b aligned in a first direction X; and a separator 4 which is disposed between the first power storage device 2a and the second power storage device 2b so as to insulate between the two power storage devices 2. The separator 4 has a frame part 24 and a heat conduction suppressing part 26. The frame part 24 has: a hole which is interposed between the first power storage device 2a and the second power storage device 2b, and which expands between the two power storage devices 2; and a locking part 27 for the heat conduction suppressing part 26. The heat conduction suppressing part 26 is disposed to close the hole and is supported by the frame part 24. The locking part 27 has: a first portion 27a which comes into contact with a surface, of the heat conduction suppressing part 26, facing a direction intersecting the first direction X; and a second portion 27b interposed between the heat conduction suppressing part 26 and the first power storage device 2a.SELECTED DRAWING: Figure 9

Description

[Technical field]

[0001] The present invention relates to an electricity storage module. [Background technology]

[0002] For example, as a power source that requires a high output voltage for use in a vehicle, etc., a power storage module in which a plurality of power storage devices (e.g., batteries) are connected in series is known. In general, a power storage module includes a plurality of power storage devices, a plurality of separators disposed between adjacent power storage devices, a pair of end plates disposed at both ends in the arrangement direction of the power storage devices, and a bind bar that is stretched between the pair of end plates and binds the plurality of power storage devices in the arrangement direction.

[0003] In addition, a typical energy storage device includes an outer can with an opening, an electrode assembly housed in the outer can, and a sealing plate that closes the opening of the outer can. Such an energy storage device tends to expand when it is charged. The expansion of the energy storage device is caused by an increase in gas pressure inside the outer can and the expansion of the electrode assembly. In conventional energy storage modules, this expansion is suppressed by end plates and bind bars.

[0004] Regarding such a storage module, Patent Document 1 discloses a battery pack including a flat rectangular secondary battery and spacers arranged on both sides of the secondary battery in the thickness direction. In this battery pack, the secondary battery had a middle region overlapping with the electrode mixture layer and a peripheral region around the middle region on the wide side. The spacer had an abutting portion abutting the peripheral region of the wide side and a hollow portion adjacent to the middle region of the wide side. The dimension of the hollow portion in the thickness direction was equal to or greater than the expansion amount of the wide side when the secondary battery was fully charged. The battery pack of Patent Document 1 avoided the middle region of the wide side from receiving a reaction force from the spacer when the battery expanded by providing a gap between the middle region of the wide side of the container and the spacer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2016-152203 Summary of the Invention [Problem to be solved by the invention]

[0006] In recent years, there has been a demand for a higher capacity for energy storage modules, and energy storage devices are being made to have higher capacities in order to meet this demand. However, as the capacity of the energy storage device increases, the expansion amount of the energy storage device may increase. In a conventional energy storage module in which the periphery of the exterior can of the energy storage device is held down by a spacer, if the expansion amount of the energy storage device increases, the load applied to the joint between the exterior can and the sealing plate during expansion becomes excessive, which may cause damage to the joint. In addition, in a structure in which the periphery of the exterior can is held down by a spacer, a large load is applied to the joint when the energy storage device is restrained by a bind bar during assembly of the energy storage module, which may cause damage to the joint. Damage to the joint leads to a decrease in the reliability of the energy storage module, and is therefore desirably avoided.

[0007] The present invention has been made in view of the above circumstances, and has a general purpose to provide a technique for improving the reliability of an electricity storage module. [Means for solving the problem]

[0008] One aspect of the present invention is an energy storage module. The energy storage module includes a plurality of energy storage devices arranged in a first direction, and a separator disposed between two adjacent energy storage devices to provide insulation between the two energy storage devices. The energy storage device includes an exterior can having an opening, a sealing plate that closes the opening, and a joint between the exterior can and the sealing plate. The separator has a contact area that contacts a surface of the exterior can facing the first direction, and a separation area that overlaps with the joint when viewed from the first direction and is recessed in a direction away from the exterior can relative to the contact area.

[0009] Any combination of the above components and any transformation of the present invention into a method, device, system, etc. are also effective as aspects of the present invention. Effect of the Invention

[0010] According to the present invention, the reliability of the electricity storage module can be improved. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of an electricity storage module according to a first embodiment. [Diagram 2] FIG. 2 is an exploded perspective view of the electricity storage device and a separator. [Diagram 3] FIG. [Figure 4] FIG. 2 is an enlarged perspective view of a portion of the separator. [Diagram 5] FIG. 2 is a cross-sectional view of a portion of the storage module. [Figure 6] 4 is an enlarged cross-sectional view showing a portion of an upper portion of the power storage module. FIG. [Figure 7] 4 is an enlarged cross-sectional view showing a portion of a lower part of the power storage module. FIG. [Figure 8] 11 is an enlarged cross-sectional view showing a portion of an upper part of an electricity storage module according to a second embodiment. FIG. [Figure 9] FIG. 11 is a perspective view of an electricity storage module according to a third embodiment. [Figure 10] FIG. 2 is an exploded perspective view of the electricity storage device and a separator. [Figure 11] FIG. [Figure 12] FIG. 2 is an enlarged perspective view of a portion of the separator. [Figure 13] FIG. 2 is a cross-sectional view of a portion of the storage module. [Figure 14] 4 is an enlarged cross-sectional view showing a portion of an upper portion of the power storage module. FIG. [Figure 15] 4 is an enlarged cross-sectional view showing a portion of a lower part of the power storage module. FIG. [Figure 16] 13 is an enlarged cross-sectional view showing a part of a lower portion of an electricity storage module according to a fourth embodiment. FIG. [Figure 17]13 is an enlarged cross-sectional view showing a portion of a lower part of an electricity storage module according to a fifth embodiment. FIG. [Figure 18] 10 is an enlarged cross-sectional view showing a part of a lower portion of an electricity storage module according to a first modified example. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The present invention will be described below with reference to the drawings based on preferred embodiments. The embodiments are illustrative and do not limit the invention, and all features and combinations thereof described in the embodiments are not necessarily essential to the invention. The same or equivalent components, members, and processes shown in each drawing are given the same reference numerals, and duplicated descriptions are omitted as appropriate. The scale and shape of each part shown in each drawing are set for convenience to facilitate explanation, and are not to be interpreted as being limiting unless otherwise specified. In addition, when terms such as "first" and "second" are used in this specification or claims, unless otherwise specified, these terms do not represent any order or importance, but are intended to distinguish one configuration from another. In addition, some of the members that are not important in explaining the embodiment in each drawing are omitted.

[0013] (Embodiment 1) Fig. 1 is a perspective view of an energy storage module according to embodiment 1. Fig. 2 is an exploded perspective view of an energy storage device and a separator. The energy storage module 1 includes a plurality of energy storage devices 2, a plurality of separators 4, a pair of end plates 6, and a pair of restraining members 8.

[0014] Each power storage device 2 is, for example, a rechargeable secondary battery such as a lithium ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery. The power storage device 2 is a so-called prismatic battery, and has an outer can 10 in the shape of a flattened rectangular parallelepiped. The outer can 10 has a rectangular opening 12 (see FIG. 5) on one side, and an electrode body 14 (see FIG. 5) including a positive electrode and a negative electrode, an electrolyte, etc. are accommodated in the outer can 10 through the opening 12. A sealing plate 16 is provided in the opening 12 to close the opening 12 and seal the outer can 10. The sealing plate 16 is, for example, a rectangular plate.

[0015] The exterior can 10 has a bottom surface 10a that faces the sealing plate 16. The exterior can 10 also has four side surfaces that connect the opening 12 and the bottom surface 10a. Two of the four side surfaces are a pair of long side surfaces 10b that are connected to two opposing long sides of the opening 12. Each long side surface 10b is the surface that has the largest area among the surfaces of the exterior can 10, i.e., a main surface. The remaining two side surfaces excluding the two long side surfaces 10b are a pair of short side surfaces that are connected to the opening 12 and the short sides of the bottom surface 10a of the exterior can 10.

[0016] The sealing plate 16 is provided with an output terminal 18 electrically connected to the positive electrode of the electrode body 14 near one end in the longitudinal direction, and an output terminal 18 electrically connected to the negative electrode of the electrode body 14 near the other end. Hereinafter, the output terminal 18 connected to the positive electrode will be referred to as the positive electrode terminal 18a, and the output terminal 18 connected to the negative electrode will be referred to as the negative electrode terminal 18b. In addition, when it is not necessary to distinguish the polarity of the output terminals 18, the positive electrode terminal 18a and the negative electrode terminal 18b will be collectively referred to as the output terminals 18. The outer can 10 and the sealing plate 16 are conductors, and are made of metals such as aluminum, iron, and stainless steel. The sealing plate 16 and the outer can 10 are joined, for example, by a laser. Therefore, the energy storage device 2 has a joint 20 between the outer can 10 and the sealing plate 16. As an example, the joint 20 is provided on the entire outer periphery of the sealing plate 16. Note that the sealing plate 16 and the outer casing 10 may be joined by friction stir welding, brazing or the like instead of by laser.

[0017] In the description of the present embodiment, for convenience, the surface on which the sealing plate 16 is provided is defined as the upper surface of the energy storage device 2. The bottom surface 10a of the exterior can 10 is defined as the bottom surface of the energy storage device 2, the long side surface 10b of the exterior can 10 is defined as the long side surface of the energy storage device 2, and the short side surface of the exterior can 10 is defined as the short side surface of the energy storage device 2. In the energy storage module 1, the surface on the upper side of the energy storage device 2 is defined as the upper surface of the energy storage module 1, the surface on the bottom side of the energy storage device 2 is defined as the bottom surface of the energy storage module 1, and the surface on the short side of the energy storage device 2 is defined as the side surface of the energy storage module 1. The upper surface side of the energy storage module 1 is defined as the upper side in the vertical direction, and the bottom surface side of the energy storage module 1 is defined as the lower side in the vertical direction. These directions and positions are defined for convenience. Therefore, for example, a portion defined as the upper surface in the present invention does not necessarily mean that it is located above a portion defined as the bottom surface. Therefore, the sealing plate 16 is not necessarily located above the bottom surface 10a of the outer can 10.

[0018] A safety valve 22 is provided on the sealing plate 16 between the pair of output terminals 18. The safety valve 22 is configured to open when the internal pressure of the outer can 10 rises to or above a predetermined value, thereby releasing the gas inside the outer can 10. The safety valve 22 of each power storage device 2 is connected to a gas duct (not shown), and the gas inside the power storage device 2 is discharged from the safety valve 22 to the gas duct. The safety valve 22 is configured, for example, by a thin-walled portion that is provided in a part of the sealing plate 16 and is thinner than other parts, and a linear groove formed on the surface of the thin-walled portion. In this configuration, when the internal pressure of the outer can 10 rises, the thin-walled portion tears starting from the groove, causing the safety valve 22 to open.

[0019] The multiple energy storage devices 2 are arranged side by side at a predetermined interval so that the long side surfaces 10b of adjacent energy storage devices 2 face each other to form an assembly. In this embodiment, the direction in which the multiple energy storage devices 2 are arranged is defined as a first direction X. The direction in which the sealing plate 16 extends is defined as a second direction Y, and the direction in which the sealing plate 16 and the bottom surface 10a are arranged is defined as a third direction Z. The output terminals 18 of each energy storage device 2 are arranged to face in the same direction. In this embodiment, the output terminals 18 of each energy storage device 2 are arranged to face vertically upward for convenience. The output terminals 18 of each energy storage device 2 may be arranged to face in different directions.

[0020] Two adjacent energy storage devices 2 are stacked such that the positive electrode terminal 18a of one energy storage device 2 and the negative electrode terminal 18b of the other energy storage device 2 are adjacent to each other. The positive electrode terminal 18a and the negative electrode terminal 18b are connected in series via a bus bar (not shown). Note that the output terminals 18 of the same polarity in a plurality of adjacent energy storage devices 2 may be connected in parallel via a bus bar to form an energy storage device block, and the energy storage device blocks may be connected in series to each other.

[0021] The separator 4, also called an insulating spacer, is disposed between two adjacent power storage devices 2 to electrically insulate the two power storage devices 2. The separator 4 of the present embodiment has a frame portion 24 and a heat conduction suppressing portion 26. The frame portion 24 is made of, for example, an insulating resin. Examples of the resin that makes up the frame portion 24 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE).

[0022] Frame 24 has locking portions 27 interposed between long side surfaces 10b of two adjacent energy storage devices 2. The presence of locking portions 27 insulates two adjacent energy storage devices 2. Frame 24 is a polygonal ring shape (a square ring shape in this embodiment) that corresponds to the shape of long side surfaces 10b, with the inside of the frame or ring corresponding to the center side of energy storage module 1 in the YZ plane and the outside of the frame or ring corresponding to the outside of energy storage module 1 in the YZ plane. The YZ plane is a plane that extends in the second direction Y and the third direction Z.

[0023] Moreover, the frame portion 24 has a wall portion 28. The wall portion 28 is connected to the outer peripheral surface of the locking portion 27 and extends in the first direction X to cover the top surface, short side surface and bottom surface of the electricity storage device 2. This makes it possible to ensure a creepage distance between adjacent electricity storage devices 2 or between the electricity storage device 2 and the end plate 6. It is also possible to restrict the position of the electricity storage device 2 in the second direction Y or the third direction Z. It is also possible to electrically insulate each electricity storage device 2 from the restraining member 8. In this embodiment, the locking portion 27 and the wall portion 28 are integrally formed.

[0024] A cutout 30 is provided in the wall portion 28 at a position corresponding to the output terminal 18 so that the output terminal 18 is exposed. The wall portion 28 is also provided with a pair of protruding walls 32 that protrude in the third direction Z in which the sealing plate 16 and the bottom surface 10a are aligned. The pair of protruding walls 32 are arranged to sandwich the cutout 30 in the second direction Y in which the sealing plate 16 extends, in other words, in the second direction Y in which the two output terminals 18 are aligned.

[0025] Furthermore, an opening 34 is provided in the wall portion 28 at a position corresponding to the safety valve 22 so that the safety valve 22 is exposed. A cylindrical duct portion 36 protruding from the wall portion 28 in the third direction Z is provided around the opening 34. The duct portion 36 surrounds the entire periphery of the opening 34. The duct portion 36 connects the safety valve 22 and a gas duct (not shown). Furthermore, a cutout portion 38 is provided in the wall portion 28 at a position corresponding to the bottom surface 10a of the outer can 10 so that a part of the bottom surface 10a is exposed. As an example, a cooling plate is thermally connected to the bottom surface 10a of the electricity storage device 2.

[0026] The heat conduction suppression section 26 is interposed between the long side surfaces 10b of two adjacent power storage devices 2 to suppress heat conduction between the two power storage devices 2. As a result, even if the temperature of any power storage device 2 rises excessively during use of the power storage module 1, the heat can be prevented from being transmitted to the adjacent power storage device 2. As a result, a chain reaction of overheating (chain reaction of thermal runaway) can be suppressed. Furthermore, the heat conduction suppression section 26 has insulating properties. The heat conduction suppression section 26 is plate-shaped or sheet-shaped, and is made of a heat insulating material and a laminate film, for example. The heat conduction suppression section 26 has a thickness of, for example, 1 to 2 mm.

[0027] The heat insulating material is in the form of a sheet, and has a structure in which a porous material such as silica xerogel is supported between fibers of a fiber sheet made of nonwoven fabric or the like. Silica xerogel has a nano-sized void structure that regulates the movement of air molecules, and has low thermal conductivity. The heat insulating material has a thermal conductivity of about 0.018 to 0.024 W / m·K. The heat insulating material is useful as a heat insulating material used in particular in a narrow space. The thermal conductivity of the heat insulating material is lower than that of air. Therefore, by providing the heat conduction suppressing portion 26, the heat conduction between the two adjacent power storage devices 2 can be suppressed more than when only an air layer is interposed between the two adjacent power storage devices 2. In addition, the heat conduction suppressing portion 26 has a lower thermal conductivity than the frame portion 24.

[0028] Furthermore, silica xerogel has a relatively high structural stability against pressure from the outside. This allows the heat insulating performance of the heat insulating material to be stably maintained. Therefore, by providing the heat conduction suppressing section 26, the power storage module 1 can more stably suppress heat conduction between the power storage devices 2. Furthermore, since the heat insulating material has a lower thermal conductivity than air, the same level of heat insulating effect can be obtained with a thinner layer thickness compared to an air layer. This allows the power storage module 1 to be prevented from becoming larger.

[0029] The laminate film is a member for wrapping and protecting the entire heat insulating material. The laminate film can prevent the porous material in the heat insulating material from falling off the fiber sheet. Furthermore, by covering the heat insulating material with the laminate film, it becomes easier to fit the heat conduction suppressing unit 26 into the frame portion 24 when assembling the power storage module 1. The laminate film is made of, for example, polyethylene terephthalate (PET) or the like.

[0030] The heat conduction suppressing portion 26 has a higher heat resistance than the frame portion 24. More specifically, the heat resistance of the heat insulating material is higher than that of the frame portion 24. More specifically, the fiber sheet contains fibers having a higher melting point than the frame portion 24, the porous material is made of a substance having a higher melting point than the frame portion 24, or both. For example, the heat insulating material has a melting point of 300°C or higher. Specifically, the melting point of the fiber sheet and / or the porous material constituting the heat insulating material is 300°C or higher. In particular, it is preferable that the melting point of the fiber constituting the fiber sheet is 300°C or higher. This allows the fiber sheet to maintain the porous material supported by the fiber sheet even when the heat insulating material is exposed to high temperatures.

[0031] By making the heat resistance of the heat conduction suppressing portion 26 higher than that of the frame portion 24, it is possible to leave the heat conduction suppressing portion 26 even if the frame portion 24 melts due to heat generation from the energy storage device 2. Therefore, even if the frame portion 24 melts, the heat conduction suppressing portion 26 can maintain insulation between the energy storage devices 2. Furthermore, the state in which heat conduction between adjacent energy storage devices 2 is suppressed can be maintained for a longer period of time.

[0032] The multiple electricity storage devices 2 and the multiple separators 4 arranged in parallel are sandwiched in the first direction X by a pair of end plates 6. As an example, separators to which heat conduction suppressing units 26 are not attached are arranged between the pair of end plates 6 and the electricity storage devices 2 located at both ends in the first direction X. This provides electrical insulation between the electricity storage devices 2 and the end plates 6 and makes it possible to avoid impeding heat dissipation from the electricity storage devices 2 via the end plates 6. The separators preferably have separation regions 48, which will be described later. The end plates 6 are made of, for example, metal plates. A screw hole (not shown) into which a screw 40 is screwed is provided on a surface of the end plates 6 facing the long side surface 10b of the exterior can 10.

[0033] The pair of binding members 8 are also called bind bars, and are elongated members with the first direction X as their longitudinal direction. The pair of binding members 8 are arranged to face each other in the second direction Y in which the pair of output terminals 18 are aligned. A plurality of power storage devices 2, a plurality of separators 4, and a pair of end plates 6 are interposed between the pair of binding members 8. Each binding member 8 has a rectangular flat portion 8a extending parallel to the short side surface of the power storage device 2, and four overhanging portions 8b protruding from each end edge of the flat portion 8a toward the power storage device 2. The two overhanging portions 8b facing each other in the first direction X are provided with through holes (not shown) through which screws 40 are inserted.

[0034] With the multiple energy storage devices 2 and the multiple separators 4 arranged alternately and sandwiched between a pair of end plates 6 in the first direction X, these are then sandwiched between a pair of restraining members 8 in the second direction Y. Each restraining member 8 is aligned so that the through hole of the eaves portion 8b overlaps with the screw hole of the end plate 6. Then, a screw 40 is inserted into the through hole and screwed into the screw hole. In this manner, the pair of restraining members 8 engage with the pair of end plates 6 to restrain the multiple energy storage devices 2. The multiple energy storage devices 2 and the multiple separators 4 are fastened by the restraining members 8 with a predetermined pressure applied in the first direction X.

[0035] The multiple power storage devices 2 are fastened in the first direction X by the restraining members 8, thereby being positioned in the first direction X. Furthermore, the top and bottom surfaces of the multiple power storage devices 2 abut against two eaves portions 8b that face each other in the third direction Z in which the top and bottom surfaces are aligned, via the wall portions 28 of the separator 4. In this way, the multiple power storage devices 2 are positioned in the third direction Z. As an example, after this positioning is completed, a bus bar is attached to the output terminals 18 of each power storage device 2, and the output terminals 18 of the multiple power storage devices 2 are electrically connected to each other. For example, the bus bar is fixed to the output terminals 18 by welding.

[0036] The upper surfaces of the multiple power storage devices 2 are covered with a cover member (not shown). The cover member is supported by the protruding wall portion 32. The cover member prevents condensed water, dust, and the like from coming into contact with the output terminals 18, bus bars, safety valves 22, and the like of the power storage devices 2. The cover member is made of, for example, an insulating resin.

[0037] FIG. 3 is a perspective view of a separator. FIG. 4 is a perspective view showing an enlarged portion of the separator. FIG. 5 is a cross-sectional view of a portion of the electricity storage module. FIG. 6 is a cross-sectional view showing an enlarged portion of an upper portion of the electricity storage module. FIG. 7 is a cross-sectional view showing an enlarged portion of a lower portion of the electricity storage module. In FIGS. 3 and 4, illustration of the heat transfer suppression unit 26 is omitted. In FIGS. 5 to 7, any two electricity storage devices 2 and a separator 4 disposed between them are illustrated as a portion of the electricity storage module 1. Also, the internal structure of the electricity storage device 2 is illustrated typically.

[0038] As described above, the separator 4 has the frame portion 24 and the heat conduction suppressing portion 26. The locking portion 27 of the frame portion 24 is interposed between two adjacent power storage devices 2, and has a hole 42 that spreads between the two power storage devices 2. The frame portion 24 also extends along the periphery of the outer can 10 when viewed from the first direction X in which the power storage devices 2 are arranged. Therefore, the hole 42 overlaps with the center of the outer can 10 when viewed from the first direction X. In other words, the hole 42 is a through hole that penetrates the separator 4 in the first direction X.

[0039] The heat conduction suppressing portion 26 is disposed so as to block the hole 42. The locking portion 27 of the frame portion 24 has a predetermined thickness in the first direction X, and has a groove portion 44 on its inner circumferential surface facing the hole 42 of the frame portion 24. The groove portion 44 extends around the entire circumference of the hole 42. The heat conduction suppressing portion 26 is supported by the frame portion 24 by having its peripheral portion fitted into the groove portion 44. It is to be noted that the groove portion 44 does not have to extend around the entire circumference of the hole 42. For example, the groove portion 44 may be formed only on both ends of the heat conduction suppressing portion 26 to hold both ends of the heat conduction suppressing portion 26.

[0040] The following method is an example of a method for installing the heat conduction suppressing portion 26 on the frame portion 24, in other words, a method for assembling the separator 4. For example, the frame portion 24 is divided into a plurality of portions (for example, two portions) in the second direction Y or the third direction Z. Then, the divided portions are arranged with the heat conduction suppressing portion 26 sandwiched therebetween, and the ends of the heat conduction suppressing portion 26 are aligned with the grooves 44 of each portion, and then the portions are brought close to each other. After the portions butt against each other, they are fixed, for example, by adhesion. As a result, the heat conduction suppressing portion 26 is supported by the frame portion 24 with its peripheral portion inserted into the grooves 44. Alternatively, a slit for inserting the heat conduction suppressing portion 26 into the hole 42 may be provided in the frame portion 24, and the heat conduction suppressing portion 26 may be inserted into the frame portion 24 through the slit. Alternatively, the frame portion 24 may be divided in the first direction X, and the separator 4 may be assembled by sandwiching the heat conduction suppressing portion 26 in the first direction X between the portions. Alternatively, the separator 4 may be formed by integrally molding the frame portion 24 and the heat conduction suppressing portion 26 .

[0041] The separator 4 also has a contact region 46 and a separation region 48. In this embodiment, the contact region 46 and the separation region 48 are disposed in the frame 24. More specifically, the contact region 46 and the separation region 48 are disposed on both side surfaces of the locking portion 27 of the frame 24 facing the first direction X in which the power storage devices 2 are arranged. The contact region 46 abuts against the surface of each outer can 10 facing the first direction X, that is, the long side surface 10b. This positions each power storage device 2 in the first direction X. Also, expansion of the outer can 10 is suppressed. The contact region 46 in this embodiment abuts against three edge portions, namely, an edge portion of the long side surface 10b adjacent to the bottom surface 10a and an edge portion adjacent to a pair of short side surfaces. Therefore, the contact region 46 is substantially U-shaped when viewed from the first direction X.

[0042] The separation region 48 has a shape that is recessed in a direction away from the exterior can 10 more than the contact region 46. The separation region 48 is disposed so as to overlap with the joint portion 20 when viewed from the first direction X. The long side surface 10b in this embodiment is rectangular, and the contact region 46 overlaps with three of the four edges of the long side surface 10b facing the first direction X, and the separation region 48 overlaps with the remaining edge of the four edges.

[0043] A gap 50 is provided between the separation region 48 of the frame 24 and the long side surface 10b of the exterior can 10. The frame 24 has the separation region 48, which makes it possible to prevent the joint 20 from being pressed by the frame 24 when the energy storage module 1 is assembled. This makes it possible to reduce the load on the joint 20 due to the pressure from the separator 4 when the energy storage module 1 is assembled. The separation region 48 may be provided so as to extend discontinuously in the second direction Y or the third direction Z.

[0044] Furthermore, in the early stage of expansion of the outer can 10, the area of ​​the outer can 10 near the joint 20 expands without being pressed by the frame 24. When the outer can 10 expands by a predetermined amount, the outer can 10 comes into contact with the separation area 48, and further expansion of the outer can 10 is suppressed. This suppresses excessive deformation of the joint 20. As a result, the load applied to the joint 20 due to the deformation can be reduced.

[0045] Moreover, the separation region 48 in the present embodiment extends over the entirety of the locking portion 27 in the second direction Y in which the sealing plate 16 extends. That is, both ends of the separation region 48 in the second direction Y contact the wall portion 28 extending parallel to the short side surface of the electricity storage device 2. Therefore, the separation region 48 overlaps with the entirety of the joint portion 20 in the second direction Y in which the sealing plate 16 extends as viewed from the first direction X. This makes it possible to more reliably reduce the load on the joint portion 20. Note that both ends of the separation region 48 in the second direction Y may be connected to the portion of the abutment region 46 extending in the third direction Z. In this case, the mechanical strength of the frame portion 24 is increased, and the reliability of holding the electricity storage device 2 is improved.

[0046] Moreover, the separation region 48 overlaps with the entire joint 20 in the thickness direction of the sealing plate 16, i.e., in the third direction Z. In other words, the separation region 48 extends from the surface of the sealing plate 16 facing the outside of the energy storage device 2 to the surface facing the internal space of the energy storage device 2. This makes it possible to more reliably reduce the load on the joint 20. Furthermore, the separation region 48 protrudes toward the surface of the exterior can 10 facing the sealing plate 16, i.e., toward the bottom surface 10a, beyond the sealing plate 16. In other words, the separation region 48 extends toward the bottom surface 10a beyond the surface of the sealing plate 16 facing the internal space of the energy storage device 2. This also makes it possible to more reliably reduce the load on the joint 20.

[0047] Furthermore, in this embodiment, the portion of the frame 24 that extends along the joint 20, i.e., the portion where the separation region 48 is located, is located outside the electrode body 14 when viewed from the first direction X. The expansion of the exterior can 10 is mainly caused by the expansion of the electrode body 14. Therefore, by locating this portion of the frame 24 outside the electrode body 14, the separation region 48 does not overlap with the electrode body 14, and the load on the joint 20 can be more reliably reduced.

[0048] Additionally, the peripheral portion of the thermal conduction suppressing portion 26 is fitted into the groove portion 44 of the frame portion 24. That is, the frame portion 24 supports the thermal conduction suppressing portion 26 by sandwiching the peripheral portion of the thermal conduction suppressing portion 26 in the first direction X. As a result, a part of the frame portion 24 is interposed between the peripheral portion of the thermal conduction suppressing portion 26 and the peripheral portion of the long side surface 10b of the exterior can 10. As a result, a gap 52 is formed between the center of the thermal conduction suppressing portion 26 and the center of the long side surface 10b.

[0049] By providing the gap 52, at least in the initial stage of expansion of the outer can 10, the center of the outer can 10 expands without hitting the heat conduction suppressing portion 26. That is, the gap 52 functions as a space that allows a predetermined amount of expansion of the outer can 10. This makes it possible to suppress deformation of the heat conduction suppressing portion 26 due to the expansion of the outer can 10, in other words, compression in the first direction X. As a result, it is possible to suppress a decrease in the heat insulating performance of the heat conduction suppressing portion 26. In addition, it is possible to reduce the load on the end plate 6 and the binding member 8. Therefore, it is possible to avoid increasing the strength of the end plate 6 and the binding member 8 as a measure against an increase in the amount of expansion of the energy storage device 2. As a result, it is possible to suppress an increase in the cost of the energy storage module 1 and a decrease in the workability of the end plate 6 and the binding member 8. The size of the gap 52 in the first direction X may be equal to or larger than the size of the gap 50 in the first direction X. With this configuration, it is possible to secure a space for the expansion of the outer can 10 while providing the separation region 48.

[0050] As described above, the energy storage module 1 according to the present embodiment includes a plurality of energy storage devices 2 and a separator 4 disposed between two adjacent energy storage devices 2 to provide insulation between the two energy storage devices 2. The energy storage device 2 includes an outer can 10 having an opening 12, a sealing plate 16 that closes the opening 12, and a joint 20 between the outer can 10 and the sealing plate 16. The separator 4 includes a contact region 46 that contacts a surface of the outer can 10 facing the first direction X in which the energy storage devices 2 are arranged, and a separation region 48 that overlaps with the joint 20 when viewed from the first direction X and is recessed in a direction away from the outer can 10 relative to the contact region 46.

[0051] Since the separator 4 has the separation region 48, the load on the joint 20 can be reduced when the plurality of energy storage devices 2 and the plurality of separators 4 are compressed in the first direction X and restrained by the restraining member 8 during assembly of the energy storage module 1. In addition, the load repeatedly applied to the joint 20 when the outer can 10 expands can be reduced. When the outer can 10 expands to a predetermined size, the outer can 10 abuts against the separation region 48, and further expansion of the outer can 10 is suppressed. This makes it possible to suppress excessive deformation of the joint 20, and reduces the load on the joint 20 due to the deformation.

[0052] As described above, the energy storage module 1 according to the present embodiment can reduce the risk of damage to the joint 20 between the exterior can 10 and the sealing plate 16, thereby improving the reliability of the energy storage device 2 and, in turn, the energy storage module 1. Furthermore, the capacity of the energy storage module 1 can be increased while maintaining the reliability of the energy storage module 1.

[0053] Furthermore, the separation region 48 overlaps with the entire joint portion 20 in the second direction Y in which the sealing plate 16 extends when viewed from the first direction X. The separation region 48 also overlaps with the entire joint portion 20 in the thickness direction of the sealing plate 16. Furthermore, the separation region 48 protrudes toward the bottom surface 10a of the outer can 10 further than the sealing plate 16. This makes it possible to more reliably reduce the load applied to the joint portion 20 when the outer can 10 expands or when the energy storage device 2 is fastened with the restraining member 8.

[0054] Moreover, the separator 4 of the present embodiment has a frame portion 24 and a heat conduction suppressing portion 26. The frame portion 24 is interposed between two adjacent power storage devices 2 and defines a hole 42 extending between the two power storage devices 2. The heat conduction suppressing portion 26 is disposed so as to close the hole 42. The contact region 46 and the separation region 48 are disposed in the frame portion 24. By interposing the heat conduction suppressing portion 26 between the two adjacent power storage devices 2, even if the temperature of any one of the power storage devices 2 rises excessively during use of the power storage module 1, the transfer of the heat to the adjacent power storage device 2 can be suppressed. Therefore, a chain reaction of overheating can be suppressed.

[0055] (Embodiment 2) Except for the shape of the frame 24, the second embodiment has a common configuration with the first embodiment. The following description of the second embodiment will focus on configurations that are different from the first embodiment, and common configurations will be explained briefly or omitted. FIG. 8 is an enlarged cross-sectional view of a portion of the upper part of the energy storage module according to the second embodiment. FIG. 8 shows a schematic diagram of the internal structure of the energy storage device 2.

[0056] The separator 4 included in the power storage module 1 according to the present embodiment has a contact region 46 and a separation region 48, similar to the first embodiment. In the present embodiment, the contact region 46 and the separation region 48 are also disposed in the frame portion 24.

[0057] Separation region 48 according to the present embodiment has an inclined surface 48a. Inclined surface 48a is inclined so as to move away from outer can 10 from sealing plate 16 toward bottom surface 10a of outer can 10 that faces sealing plate 16. Inclined surface 48a is disposed at the end of the portion of frame 24 that extends along joint 20 on the hole 42 side. Therefore, the portion of frame 24 that extends along joint 20 has a tapered portion whose thickness (size in first direction X) becomes thinner from the outside of energy storage module 1 toward the center.

[0058] Therefore, the gap 50 provided between the separation region 48 and the long side surface 10b gradually expands from the outside to the center of the energy storage module 1 in the region where the inclined surface 48a extends. The amount of expansion of the outer can 10 is greater in the central portion than in the peripheral portion. In contrast, by providing the inclined surface 48a in the separation region 48, the expansion of the outer can 10 can be more reliably tolerated. Thus, the load on the joint 20 can be more reliably reduced. In addition, the risk of the frame 24 being pressed against the outer can 10, causing damage such as dents to the outer can 10 or the insulating tape covering the outer surface of the outer can 10, can be reduced. The inclined surface 48a may extend over the entire separation region 48 in the third direction Z.

[0059] (Embodiment 3) In a conventional energy storage module in which a heat conduction suppression unit is disposed between adjacent energy storage devices, when the amount of expansion of the energy storage devices increases, the heat conduction suppression unit is excessively compressed in the arrangement direction of the energy storage devices, reducing the dimension in the arrangement direction, thereby shortening the heat transfer path in the arrangement direction, and there is a risk of a decrease in insulation performance. Since a decrease in the insulation performance of the heat conduction suppression unit leads to a decrease in the reliability of the energy storage module, it is desirable to avoid this.

[0060] Fig. 9 is a perspective view of an energy storage module according to embodiment 3. Fig. 10 is an exploded perspective view of an energy storage device and a separator. The energy storage module 1 includes a plurality of energy storage devices 2, a plurality of separators 4, a pair of end plates 6, and a pair of binding members 8.

[0061] Each power storage device 2 is, for example, a rechargeable secondary battery such as a lithium ion battery, a nickel-hydrogen battery, or a nickel-cadmium battery. The power storage device 2 is a so-called prismatic battery, and has an outer can 10 in the shape of a flattened rectangular parallelepiped. The outer can 10 has a rectangular opening 12 (see FIG. 13) on one side, and an electrode body 14 (see FIG. 13) including a positive electrode and a negative electrode, an electrolyte, etc. are accommodated in the outer can 10 through the opening 12. A sealing plate 16 that closes the opening 12 and seals the outer can 10 is provided in the opening 12. The sealing plate 16 is, for example, a rectangular plate.

[0062] The exterior can 10 has a bottom surface 10a that faces the sealing plate 16. The exterior can 10 also has four side surfaces that connect the opening 12 and the bottom surface 10a. Two of the four side surfaces are a pair of long side surfaces 10b that are connected to two opposing long sides of the opening 12. Each long side surface 10b is the surface that has the largest area among the surfaces of the exterior can 10, i.e., a main surface. The remaining two side surfaces excluding the two long side surfaces 10b are a pair of short side surfaces that are connected to the opening 12 and the short sides of the bottom surface 10a of the exterior can 10.

[0063] The sealing plate 16 is provided with an output terminal 18 electrically connected to the positive electrode of the electrode body 14 near one end in the longitudinal direction, and an output terminal 18 electrically connected to the negative electrode of the electrode body 14 near the other end. Hereinafter, the output terminal 18 connected to the positive electrode will be referred to as the positive electrode terminal 18a, and the output terminal 18 connected to the negative electrode will be referred to as the negative electrode terminal 18b. In addition, when it is not necessary to distinguish the polarity of the output terminals 18, the positive electrode terminal 18a and the negative electrode terminal 18b will be collectively referred to as the output terminals 18. The outer can 10 and the sealing plate 16 are conductors, and are made of metals such as aluminum, iron, and stainless steel. The sealing plate 16 and the outer can 10 are joined, for example, by a laser. Therefore, the energy storage device 2 has a joint 20 between the outer can 10 and the sealing plate 16. As an example, the joint 20 is provided on the entire outer periphery of the sealing plate 16. Note that the sealing plate 16 and the outer casing 10 may be joined by friction stir welding, brazing or the like instead of by laser.

[0064] In the description of the present embodiment, for convenience, the surface on which the sealing plate 16 is provided is defined as the upper surface of the energy storage device 2. The bottom surface 10a of the exterior can 10 is defined as the bottom surface of the energy storage device 2, the long side surface 10b of the exterior can 10 is defined as the long side surface of the energy storage device 2, and the short side surface of the exterior can 10 is defined as the short side surface of the energy storage device 2. In the energy storage module 1, the surface on the upper side of the energy storage device 2 is defined as the upper surface of the energy storage module 1, the surface on the bottom side of the energy storage device 2 is defined as the bottom surface of the energy storage module 1, and the surface on the short side of the energy storage device 2 is defined as the side surface of the energy storage module 1. The upper surface side of the energy storage module 1 is defined as the upper side in the vertical direction, and the bottom surface side of the energy storage module 1 is defined as the lower side in the vertical direction. These directions and positions are defined for convenience. Therefore, for example, a portion defined as the upper surface in the present invention does not necessarily mean that it is located above a portion defined as the bottom surface. Therefore, the sealing plate 16 is not necessarily located above the bottom surface 10a of the outer can 10.

[0065] A safety valve 22 is provided on the sealing plate 16 between the pair of output terminals 18. The safety valve 22 is configured to open when the internal pressure of the outer can 10 rises to or above a predetermined value, thereby releasing the gas inside the outer can 10. The safety valve 22 of each power storage device 2 is connected to a gas duct (not shown), and the gas inside the power storage device 2 is discharged from the safety valve 22 to the gas duct. The safety valve 22 is configured, for example, by a thin-walled portion that is provided in a part of the sealing plate 16 and is thinner than other parts, and a linear groove formed on the surface of the thin-walled portion. In this configuration, when the internal pressure of the outer can 10 rises, the thin-walled portion tears starting from the groove, causing the safety valve 22 to open.

[0066] The multiple energy storage devices 2 are arranged side by side at a predetermined interval so that the long side surfaces 10b of adjacent energy storage devices 2 face each other to form an assembly. In this embodiment, the direction in which the multiple energy storage devices 2 are arranged is defined as a first direction X. The direction in which the sealing plate 16 extends is defined as a second direction Y, and the direction in which the sealing plate 16 and the bottom surface 10a are arranged is defined as a third direction Z. The output terminals 18 of each energy storage device 2 are arranged to face in the same direction. In this embodiment, the output terminals 18 of each energy storage device 2 are arranged to face vertically upward for convenience. The output terminals 18 of each energy storage device 2 may be arranged to face in different directions.

[0067] Two adjacent energy storage devices 2 are stacked such that the positive electrode terminal 18a of one energy storage device 2 and the negative electrode terminal 18b of the other energy storage device 2 are adjacent to each other. The positive electrode terminal 18a and the negative electrode terminal 18b are connected in series via a bus bar (not shown). Note that the output terminals 18 of the same polarity in a plurality of adjacent energy storage devices 2 may be connected in parallel via a bus bar to form an energy storage device block, and the energy storage device blocks may be connected in series to each other.

[0068] The separator 4, also called an insulating spacer, is disposed between two adjacent power storage devices 2 to electrically insulate the two power storage devices 2. The separator 4 of the present embodiment has a frame portion 24 and a heat conduction suppressing portion 26. The frame portion 24 is made of, for example, an insulating resin. Examples of the resin that makes up the frame portion 24 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE).

[0069] Frame 24 has locking portions 27 interposed between long side surfaces 10b of two adjacent energy storage devices 2. The presence of locking portions 27 insulates two adjacent energy storage devices 2. Frame 24 is a polygonal ring shape (a square ring shape in this embodiment) that corresponds to the shape of long side surfaces 10b, with the inside of the frame or ring corresponding to the center side of energy storage module 1 in the YZ plane and the outside of the frame or ring corresponding to the outside of energy storage module 1 in the YZ plane. The YZ plane is a plane that extends in the second direction Y and the third direction Z.

[0070] Moreover, the frame portion 24 has a wall portion 28. The wall portion 28 is connected to the outer peripheral surface of the locking portion 27 and extends in the first direction X to cover the top surface, short side surface and bottom surface of the electricity storage device 2. This makes it possible to ensure a creepage distance between adjacent electricity storage devices 2 or between the electricity storage device 2 and the end plate 6. It is also possible to restrict the position of the electricity storage device 2 in the second direction Y or the third direction Z. It is also possible to electrically insulate each electricity storage device 2 from the restraining member 8. In this embodiment, the locking portion 27 and the wall portion 28 are integrally formed.

[0071] A cutout 30 is provided in the wall portion 28 at a position corresponding to the output terminal 18 so that the output terminal 18 is exposed. The wall portion 28 is also provided with a pair of protruding walls 32 that protrude in the third direction Z in which the sealing plate 16 and the bottom surface 10a are aligned. The pair of protruding walls 32 are arranged to sandwich the cutout 30 in the second direction Y in which the sealing plate 16 extends, in other words, in the second direction Y in which the two output terminals 18 are aligned.

[0072] Furthermore, an opening 34 is provided in the wall portion 28 at a position corresponding to the safety valve 22 so that the safety valve 22 is exposed. A cylindrical duct portion 36 protruding from the wall portion 28 in the third direction Z is provided around the opening 34. The duct portion 36 surrounds the entire periphery of the opening 34. The duct portion 36 connects the safety valve 22 and a gas duct (not shown). Furthermore, a cutout portion 38 is provided in the wall portion 28 at a position corresponding to the bottom surface 10a of the outer can 10 so that a part of the bottom surface 10a is exposed. As an example, a cooling plate is thermally connected to the bottom surface 10a of the electricity storage device 2.

[0073] The heat conduction suppression section 26 is interposed between the long side surfaces 10b of two adjacent power storage devices 2 to suppress heat conduction between the two power storage devices 2. As a result, even if the temperature of any power storage device 2 rises excessively during use of the power storage module 1, the heat can be prevented from being transmitted to the adjacent power storage device 2. As a result, a chain reaction of overheating (chain reaction of thermal runaway) can be suppressed. Furthermore, the heat conduction suppression section 26 has insulating properties. The heat conduction suppression section 26 is plate-shaped or sheet-shaped, and is made of a heat insulating material and a laminate film, for example. The heat conduction suppression section 26 has a thickness of, for example, 1 to 2 mm.

[0074] The heat insulating material is in the form of a sheet, and has a structure in which a porous material such as silica xerogel is supported between fibers of a fiber sheet made of nonwoven fabric or the like. Silica xerogel has a nano-sized void structure that regulates the movement of air molecules, and has low thermal conductivity. The heat insulating material has a thermal conductivity of about 0.018 to 0.024 W / m·K. The heat insulating material is useful as a heat insulating material used in particular in a narrow space. The thermal conductivity of the heat insulating material is lower than that of air. Therefore, by providing the heat conduction suppressing portion 26, the heat conduction between the two adjacent power storage devices 2 can be suppressed more than when only an air layer is interposed between the two adjacent power storage devices 2. In addition, the heat conduction suppressing portion 26 has a lower thermal conductivity than the frame portion 24.

[0075] Furthermore, silica xerogel has a relatively high structural stability against pressure from the outside. This allows the heat insulating performance of the heat insulating material to be stably maintained. Therefore, by providing the heat conduction suppressing section 26, the power storage module 1 can more stably suppress heat conduction between the power storage devices 2. Furthermore, since the heat insulating material has a lower thermal conductivity than air, the same level of heat insulating effect can be obtained with a thinner layer thickness compared to an air layer. This allows the power storage module 1 to be prevented from becoming larger.

[0076] The laminate film is a member for wrapping and protecting the entire heat insulating material. The laminate film can prevent the porous material in the heat insulating material from falling off the fiber sheet. Furthermore, by covering the heat insulating material with the laminate film, it becomes easier to fit the heat conduction suppressing unit 26 into the frame portion 24 when assembling the power storage module 1. The laminate film is made of, for example, polyethylene terephthalate (PET) or the like.

[0077] The heat conduction suppressing portion 26 has a higher heat resistance than the frame portion 24. More specifically, the heat resistance of the heat insulating material is higher than that of the frame portion 24. More specifically, the fiber sheet contains fibers having a higher melting point than the frame portion 24, the porous material is made of a substance having a higher melting point than the frame portion 24, or both. For example, the heat insulating material has a melting point of 300°C or higher. Specifically, the melting point of the fiber sheet and / or the porous material constituting the heat insulating material is 300°C or higher. In particular, it is preferable that the melting point of the fiber constituting the fiber sheet is 300°C or higher. This allows the fiber sheet to maintain the porous material supported by the fiber sheet even when the heat insulating material is exposed to high temperatures.

[0078] By making the heat resistance of the heat conduction suppressing portion 26 higher than that of the frame portion 24, it is possible to leave the heat conduction suppressing portion 26 even if the frame portion 24 melts due to heat generation from the energy storage device 2. Therefore, even if the frame portion 24 melts, the heat conduction suppressing portion 26 can maintain insulation between the energy storage devices 2. Furthermore, the state in which heat conduction between adjacent energy storage devices 2 is suppressed can be maintained for a longer period of time.

[0079] The multiple electricity storage devices 2 and the multiple separators 4 arranged in parallel are sandwiched in the first direction X by a pair of end plates 6. As an example, separators to which heat conduction suppressing units 26 are not attached are arranged between the pair of end plates 6 and the electricity storage devices 2 located at both ends in the first direction X. This provides electrical insulation between the electricity storage devices 2 and the end plates 6 and makes it possible to avoid impeding heat dissipation from the electricity storage devices 2 via the end plates 6. The separators preferably have separation regions 48, which will be described later. The end plates 6 are made of, for example, metal plates. A screw hole (not shown) into which a screw 40 is screwed is provided on a surface of the end plates 6 facing the long side surface 10b of the exterior can 10.

[0080] The pair of binding members 8 are also called bind bars, and are elongated members with the first direction X as their longitudinal direction. The pair of binding members 8 are arranged to face each other in the second direction Y in which the pair of output terminals 18 are aligned. A plurality of power storage devices 2, a plurality of separators 4, and a pair of end plates 6 are interposed between the pair of binding members 8. Each binding member 8 has a rectangular flat portion 8a extending parallel to the short side surface of the power storage device 2, and four overhanging portions 8b protruding from each end edge of the flat portion 8a toward the power storage device 2. The two overhanging portions 8b facing each other in the first direction X are provided with through holes (not shown) through which screws 40 are inserted.

[0081] With the multiple energy storage devices 2 and the multiple separators 4 arranged alternately and sandwiched between a pair of end plates 6 in the first direction X, these are then sandwiched between a pair of restraining members 8 in the second direction Y. Each restraining member 8 is aligned so that the through hole of the eaves portion 8b overlaps with the screw hole of the end plate 6. Then, a screw 40 is inserted into the through hole and screwed into the screw hole. In this manner, the pair of restraining members 8 engage with the pair of end plates 6 to restrain the multiple energy storage devices 2. The multiple energy storage devices 2 and the multiple separators 4 are fastened by the restraining members 8 with a predetermined pressure applied in the first direction X.

[0082] The multiple power storage devices 2 are fastened in the first direction X by the restraining members 8, thereby being positioned in the first direction X. Furthermore, the top and bottom surfaces of the multiple power storage devices 2 abut against two eaves portions 8b that face each other in the third direction Z in which the top and bottom surfaces are aligned, via the wall portions 28 of the separator 4. In this way, the multiple power storage devices 2 are positioned in the third direction Z. As an example, after this positioning is completed, a bus bar is attached to the output terminals 18 of each power storage device 2, and the output terminals 18 of the multiple power storage devices 2 are electrically connected to each other. For example, the bus bar is fixed to the output terminals 18 by welding.

[0083] The upper surfaces of the multiple power storage devices 2 are covered with a cover member (not shown). The cover member is supported by the protruding wall portion 32. The cover member prevents condensed water, dust, and the like from coming into contact with the output terminals 18, bus bars, safety valves 22, and the like of the power storage devices 2. The cover member is made of, for example, an insulating resin.

[0084] FIG. 11 is a perspective view of a separator. FIG. 12 is a perspective view showing an enlarged portion of a separator. FIG. 13 is a cross-sectional view of a portion of a power storage module. FIG. 14 is a cross-sectional view showing an enlarged portion of an upper portion of a power storage module. FIG. 15 is a cross-sectional view showing an enlarged portion of a lower portion of a power storage module. In FIG. 11 and FIG. 12, the heat conduction suppressing unit 26 is omitted. The power storage module 1 includes a first power storage device 2a and a second power storage device 2b adjacent to each other. In FIG. 13 to FIG. 15, the first power storage device 2a and the second power storage device 2b, and the separator 4 disposed between them are illustrated as a portion of the power storage module 1. Hereinafter, when it is not necessary to distinguish between the first power storage device 2a and the second power storage device 2b, they will be collectively referred to as the power storage device 2 as appropriate. In addition, in FIG. 13 to FIG. 15, the internal structure of each power storage device 2 is illustrated in a schematic manner.

[0085] The separator 4 is disposed between the first and second power storage devices 2a and 2b arranged in the first direction X, and insulates the two power storage devices 2 from each other. As described above, the separator 4 has the frame 24 and the heat conduction suppressing portion 26. The locking portion 27 of the frame 24 is interposed between the first and second power storage devices 2a and 2b, and has a hole 42 extending between the two power storage devices 2. The frame 24 extends along the periphery of the outer can 10 as viewed from the first direction X in which the power storage devices 2 are arranged. Therefore, the hole 42 overlaps with the center of the outer can 10 as viewed from the first direction X. In other words, the hole 42 is a through hole that penetrates the separator 4 in the first direction X.

[0086] The heat conduction suppressing portion 26 is disposed so as to block the hole 42. The locking portion 27 of the frame portion 24 has a predetermined thickness in the first direction X, and has a groove portion 44 on its inner circumferential surface facing the hole 42 of the frame portion 24. The groove portion 44 extends around the entire circumference of the hole 42. The heat conduction suppressing portion 26 is supported by the frame portion 24 by having its peripheral portion fitted into the groove portion 44. It is to be noted that the groove portion 44 does not have to extend around the entire circumference of the hole 42. For example, the groove portion 44 may be formed only on both ends of the heat conduction suppressing portion 26 to hold both ends of the heat conduction suppressing portion 26.

[0087] The frame 24 of the present embodiment has a locking portion 27 as a structure for locking the heat conduction suppressing portion 26. The locking portion 27 has a first portion 27a, a second portion 27b, and a third portion 27c. The groove 44 is defined by the first portion 27a, the second portion 27b, and the third portion 27c. Specifically, the first portion 27a to the third portion 27c are each frame-shaped, and the second portion 27b, the first portion 27a, and the third portion 27c are arranged in this order in the first direction X. That is, the first portion 27a is sandwiched between the second portion 27b and the third portion 27c in the first direction X.

[0088] Moreover, the second portion 27b is disposed between the first portion 27a and the first electricity storage device 2a, and the third portion 27c is disposed between the first portion 27a and the second electricity storage device 2b. In this embodiment, the first portion 27a, the second portion 27b, and the third portion 27c are integrally formed. Moreover, the outer peripheral surfaces of the first portion 27a to the third portion 27c are each connected to the inner peripheral surface of the wall portion 28. The protruding height of each locking portion from the inner peripheral surface of the wall portion 28 of the second portion 27b and the third portion 27c is greater than that of the first portion 27a.

[0089] Therefore, the bottom surface of the groove 44 is formed by the inner circumferential surface 54 of the first portion 27a. One side surface of the groove 44 is formed by a region of a side surface 56 of the second portion 27b facing the second power storage device 2b side that protrudes more inwardly of the frame portion 24 than the inner circumferential surface 54. The other side surface of the groove 44 is formed by a region of a side surface 58 of the third portion 27c facing the first power storage device 2a side that protrudes more inwardly of the frame portion 24 than the inner circumferential surface 54. The protruding height of the first portion 27a may be 0. In other words, the region of the inner circumferential surface of the wall portion 28 that is sandwiched between the second portion 27b and the third portion 27c may form the first portion 27a.

[0090] The first portion 27a abuts against a surface 26a of the thermal conduction suppressing portion 26 facing a direction intersecting with the first direction X. The surface 26a is a surface of the thermal conduction suppressing portion 26 facing the outside of the frame portion 24, or a surface of the thermal conduction suppressing portion 26 extending in the first direction X. The second portion 27b is interposed between the thermal conduction suppressing portion 26 and the first power storage device 2a. That is, the second portion 27b is sandwiched between the peripheral portion of the thermal conduction suppressing portion 26 and the peripheral portion of the exterior can 10 of the first power storage device 2a. The third portion 27c is interposed between the thermal conduction suppressing portion 26 and the second power storage device 2b. That is, the third portion 27c is sandwiched between the peripheral portion of the thermal conduction suppressing portion 26 and the peripheral portion of the exterior can 10 of the second power storage device 2b.

[0091] In this manner, the second portion 27b and the third portion 27c are interposed between the peripheral portion of the heat conduction suppression portion 26 and the peripheral portion of the exterior can 10 of each adjacent power storage device 2, and thus a gap 52 is formed between the center portion of the heat conduction suppression portion 26 and the center portion of each exterior can 10. By providing the gap 52, at least in the initial stage of expansion of each exterior can 10, the center portion of each exterior can 10 expands without contacting the heat conduction suppression portion 26. In other words, the gap 52 functions as a space that allows a predetermined amount of expansion of each exterior can 10. This makes it possible to reduce the amount of compression of the heat conduction suppression portion 26 in the first direction X due to the expansion of each exterior can 10. As a result, it is possible to suppress a decrease in the heat insulating performance of the heat conduction suppression portion 26. In addition, the expanded portion of the exterior can 10 presses the end plate 6 and the restraining member 8, and thus the load on the end plate 6 and the restraining member 8 can also be reduced.

[0092] An elastic body (not shown) may be interposed between the heat conduction suppression portion 26 and the power storage device 2 adjacent to the heat conduction suppression portion 26 instead of the gap 52. The elastic body is, for example, a member having a lower elastic modulus than the heat conduction suppression portion 26. In this case, when the power storage device 2 expands, the elastic body is compressed preferentially over the heat conduction suppression portion 26. This makes it possible to prevent the heat conduction suppression portion 26 from being excessively compressed by the expanded power storage device 2 and being plastically deformed. When the heat conduction suppression portion 26 is interposed between two power storage devices 2, the elastic body may also be disposed so as to sandwich the sheet-shaped heat conduction suppression portion 26. The elastic body may be interposed not only between the heat conduction suppression portion 26 and the power storage device 2, but also between the contact region 46 of the separator 4 and the power storage device 2.

[0093] Although the locking portion 27 of the present embodiment has both the second portion 27b and the third portion 27c, the locking portion 27 may have only the second portion 27b, as in Modification 1 described later. Since the locking portion 27 has the second portion 27b, a gap 52 can be provided between at least the thermal conduction suppressing portion 26 and the outer can 10 of the first power storage device 2a. This allows the gap 52 to accommodate the expansion of the outer can 10 of the first power storage device 2a. Furthermore, when the outer can 10 of the second power storage device 2b expands, the thermal conduction suppressing portion 26 is pressed toward the first power storage device 2a, but the thermal conduction suppressing portion 26 can be displaced within the gap 52 toward the first power storage device 2a. Therefore, even if the frame portion 24 does not have the third portion 27c, the amount of compression of the thermal conduction suppressing portion 26 due to the expansion of each outer can 10 can be reduced.

[0094] The following method is an example of a method for installing the heat conduction suppressing portion 26 on the frame portion 24, in other words, a method for assembling the separator 4. For example, the frame portion 24 is divided into a plurality of portions (for example, two portions) in the second direction Y or the third direction Z. Then, the divided portions are arranged with the heat conduction suppressing portion 26 sandwiched therebetween, and the ends of the heat conduction suppressing portion 26 are aligned with the grooves 44 of each portion, and then the portions are brought close to each other. After the portions butt against each other, they are fixed, for example, by adhesion. As a result, the heat conduction suppressing portion 26 is supported by the frame portion 24 with its peripheral portion inserted into the grooves 44. Alternatively, a slit for inserting the heat conduction suppressing portion 26 into the hole 42 may be provided in the frame portion 24, and the heat conduction suppressing portion 26 may be inserted into the frame portion 24 through the slit. Alternatively, the frame portion 24 may be divided in the first direction X, and the separator 4 may be assembled by sandwiching the heat conduction suppressing portion 26 in the first direction X between the portions. Alternatively, the separator 4 may be formed by integrally molding the frame portion 24 and the heat conduction suppressing portion 26 .

[0095] The separator 4 also has a contact region 46 and a separation region 48. In this embodiment, the contact region 46 and the separation region 48 are disposed in the frame portion 24. More specifically, the contact region 46 and the separation region 48 are disposed in the side surface of the second portion 27b facing the first power storage device 2a and the side surface of the third portion 27c facing the second power storage device 2b. The contact region 46 contacts the surface of each outer can 10 facing the first direction X, that is, the long side surface 10b. This positions each power storage device 2 in the first direction X. Also, the expansion of the outer can 10 is suppressed. The contact region 46 in this embodiment contacts three edges, namely, an edge portion of the long side surface 10b adjacent to the bottom surface 10a and edges adjacent to a pair of short side surfaces. Therefore, the contact region 46 is substantially U-shaped when viewed from the first direction X.

[0096] The separation region 48 has a shape that is recessed in a direction away from the exterior can 10 more than the contact region 46. The separation region 48 is disposed so as to overlap with the joint portion 20 when viewed from the first direction X. The long side surface 10b in this embodiment is rectangular, and the contact region 46 overlaps with three of the four edges of the long side surface 10b facing the first direction X, and the separation region 48 overlaps with the remaining edge of the four edges.

[0097] A gap 50 is provided between the separation region 48 of the frame 24 and the long side surface 10b of the exterior can 10. The frame 24 has the separation region 48, which makes it possible to prevent the joint 20 from being pressed by the frame 24 when the energy storage module 1 is assembled. This makes it possible to reduce the load on the joint 20 due to the pressure from the separator 4 when the energy storage module 1 is assembled. The separation region 48 may be provided so as to extend discontinuously in the second direction Y or the third direction Z.

[0098] Furthermore, in the early stage of expansion of the outer can 10, the area of ​​the outer can 10 near the joint 20 expands without being pressed by the frame 24. When the outer can 10 expands by a predetermined amount, the outer can 10 comes into contact with the separation area 48, and further expansion of the outer can 10 is suppressed. This suppresses excessive deformation of the joint 20. As a result, the load applied to the joint 20 due to the deformation can be reduced.

[0099] Moreover, the separation region 48 in the present embodiment extends over the entirety of the locking portion 27 in the second direction Y in which the sealing plate 16 extends. That is, both ends of the separation region 48 in the second direction Y contact the wall portion 28 extending parallel to the short side surface of the electricity storage device 2. Therefore, the separation region 48 overlaps with the entirety of the joint portion 20 in the second direction Y in which the sealing plate 16 extends as viewed from the first direction X. This makes it possible to more reliably reduce the load on the joint portion 20. Note that both ends of the separation region 48 in the second direction Y may be connected to the portion of the abutment region 46 extending in the third direction Z. In this case, the mechanical strength of the frame portion 24 is increased, and the reliability of holding the electricity storage device 2 is improved.

[0100] Moreover, the separation region 48 overlaps with the entire joint 20 in the thickness direction of the sealing plate 16, i.e., in the third direction Z. In other words, the separation region 48 extends from the surface of the sealing plate 16 facing the outside of the energy storage device 2 to the surface facing the internal space of the energy storage device 2. This makes it possible to more reliably reduce the load on the joint 20. Furthermore, the separation region 48 protrudes toward the surface of the exterior can 10 facing the sealing plate 16, i.e., toward the bottom surface 10a, beyond the sealing plate 16. In other words, the separation region 48 extends toward the bottom surface 10a beyond the surface of the sealing plate 16 facing the internal space of the energy storage device 2. This also makes it possible to more reliably reduce the load on the joint 20.

[0101] Furthermore, in this embodiment, the portion of the frame 24 that extends along the joint 20, i.e., the portion where the separation region 48 is located, is located outside the electrode body 14 when viewed from the first direction X. The expansion of the exterior can 10 is mainly caused by the expansion of the electrode body 14. Therefore, by locating this portion of the frame 24 outside the electrode body 14, the separation region 48 does not overlap with the electrode body 14, and the load on the joint 20 can be more reliably reduced.

[0102] As described above, the power storage module 1 according to this embodiment includes the first power storage device 2a and the second power storage device 2b aligned in the first direction X, and the separator 4 disposed between the first power storage device 2a and the second power storage device 2b to provide insulation between the two power storage devices 2. The separator 4 has a frame portion 24 and a heat conduction suppressing portion 26. The frame portion 24 is interposed between the first power storage device 2a and the second power storage device 2b, and has a hole 42 extending between the two power storage devices 2, and an engagement portion 27 for the heat conduction suppressing portion 26. The heat conduction suppressing portion 26 is disposed so as to cover the hole 42 and is supported by the frame portion 24. The engagement portion 27 has a first portion 27a that abuts against a surface 26a of the heat conduction suppression portion 26 that faces a direction intersecting the first direction X, and a second portion 27b that is interposed between the heat conduction suppression portion 26 and the first power storage device 2a.

[0103] The second portion 27b is interposed between the thermal conduction suppression portion 26 and the first power storage device 2a, so that a gap 52 can be formed between the thermal conduction suppression portion 26 and the first power storage device 2a. More specifically, the second portion 27b is inserted between the peripheral portion of the thermal conduction suppression portion 26 and the peripheral portion of the first power storage device 2a. This makes it possible to more reliably form the gap 52 between the central portion of the thermal conduction suppression portion 26 and the central portion of the first power storage device 2a.

[0104] This can prevent the thermal conduction suppressing portion 26 from being compressed in the first direction X due to expansion of the first power storage device 2a and / or the second power storage device 2b adjacent to the separator 4. As a result, the change in thickness of the thermal conduction suppressing portion 26 in the first direction X can be reduced, and therefore the deterioration of the heat insulating performance of the thermal conduction suppressing portion 26 can be suppressed. As described above, according to the present embodiment, the deterioration of the reliability of the power storage module 1 can be suppressed. Furthermore, the capacity of the power storage module 1 can be increased while maintaining the reliability of the power storage module 1.

[0105] Furthermore, by providing gap 52 and allowing a predetermined amount of expansion of the energy storage device 2, the load on the end plates 6 and the restraining members 8 can be reduced. This makes it possible to avoid increasing the strength of the end plates 6 and the restraining members 8 as a measure against an increase in the amount of expansion of the energy storage device 2. As a result, it is possible to suppress an increase in the cost of the energy storage module 1 and a decrease in the workability of the end plates 6 and the restraining members 8. The size of gap 52 in the first direction X may be equal to or greater than the size of gap 50 in the first direction X. With this configuration, it is possible to ensure a space for the expansion of exterior can 10 while providing separation region 48.

[0106] Moreover, the locking portion 27 of the present embodiment has a third portion 27c interposed between the heat conduction suppression portion 26 and the second power storage device 2b. This allows the gap 52 to be formed not only between the heat conduction suppression portion 26 and the first power storage device 2a, but also between the heat conduction suppression portion 26 and the second power storage device 2b. More specifically, the third portion 27c is inserted between the peripheral portion of the heat conduction suppression portion 26 and the peripheral portion of the second power storage device 2b. This allows the gap 52 to be more reliably formed between the center portion of the heat conduction suppression portion 26 and the center portion of the second power storage device 2b. This makes it possible to further suppress compression of the heat conduction suppression portion 26 due to expansion of the first power storage device 2a and / or the second power storage device 2b. As a result, it is possible to further suppress deterioration in the reliability of the power storage module 1.

[0107] Moreover, the electricity storage device 2 of the present embodiment has an outer can 10 having an opening 12, a sealing plate 16 that closes the opening 12, and a joint 20 between the outer can 10 and the sealing plate 16. The frame 24 has a contact region 46 that abuts against the surface of the outer can 10 facing the first direction X, and a separation region 48 that overlaps with the joint 20 when viewed from the first direction X and is recessed in a direction away from the outer can 10 than the contact region 46.

[0108] The separator 4 has the separation region 48, so that the load on the joint 20 can be reduced when the plurality of energy storage devices 2 and the plurality of separators 4 are compressed in the first direction X and restrained by the restraining member 8 during assembly of the energy storage module 1. In addition, the load repeatedly applied to the joint 20 when the outer casing 10 expands can be reduced.

[0109] Furthermore, when the exterior can 10 expands to a predetermined size, the exterior can 10 comes into contact with the separation region 48, suppressing further expansion of the exterior can 10. This makes it possible to suppress excessive deformation of the joint 20, and reduce the load on the joint 20 due to the deformation. Therefore, according to the energy storage module 1 of this embodiment, it is possible to reduce the risk of damage to the joint 20 between the exterior can 10 and the sealing plate 16, thereby improving the reliability of the energy storage device 2 and, ultimately, the energy storage module 1.

[0110] Furthermore, the separation region 48 overlaps with the entire joint portion 20 in the second direction Y in which the sealing plate 16 extends when viewed from the first direction X. The separation region 48 also overlaps with the entire joint portion 20 in the thickness direction of the sealing plate 16. Furthermore, the separation region 48 protrudes toward the bottom surface 10a of the outer can 10 further than the sealing plate 16. This makes it possible to more reliably reduce the load applied to the joint portion 20 when the outer can 10 expands or when the energy storage device 2 is fastened with the restraining member 8.

[0111] (Embodiment 4) Except for the shape of the frame 24, the fourth embodiment has a common configuration with the third embodiment. The following description of the present embodiment will focus on the configuration that differs from the third embodiment, and the common configuration will be explained briefly or omitted. Fig. 16 is an enlarged cross-sectional view of a portion of the lower part of the energy storage module according to the fourth embodiment. Fig. 16 shows a schematic diagram of the internal structure of the energy storage device 2.

[0112] The separator 4 included in the power storage module 1 according to the present embodiment has a frame portion 24 and a heat conduction suppression portion 26, similar to the third embodiment. The frame portion 24 is interposed between the first power storage device 2a and the second power storage device 2b, and has a hole 42 extending between the two power storage devices 2 and a locking portion 27 of the heat conduction suppression portion 26. The locking portion 27 has a first portion 27a, a second portion 27b, and a third portion 27c. The heat conduction suppression portion 26 is disposed so as to close the hole 42 and is supported by the frame portion 24. The first portion 27a abuts against a surface 26a of the heat conduction suppression portion 26 facing a direction intersecting with the first direction X. The second portion 27b is interposed between the heat conduction suppression portion 26 and the first power storage device 2a. The third portion 27c is interposed between the heat conduction suppression portion 26 and the second power storage device 2b.

[0113] Moreover, the second portion 27b of the present embodiment has a first inclined surface 60 on a side facing the thermal conduction suppression portion 26, i.e., on a side surface 56 of the second portion 27b facing the second power storage device 2b. The first inclined surface 60 is inclined so as to move away from the thermal conduction suppression portion 26 from the outside to the inside of the frame portion 24. The first inclined surface 60 is disposed at an end of the second portion 27b on the hole 42 side. Therefore, the second portion 27b has a tapered portion whose thickness (size in the first direction X) becomes thinner from the outside to the center of the power storage module 1.

[0114] The energy storage device 2 expands more in the center than in the peripheral portion. Therefore, when the expansion of the second energy storage device 2b presses the heat conduction suppressing portion 26 toward the first energy storage device 2a, the heat conduction suppressing portion 26 is pressed against a corner of the second portion 27b, and the heat conduction suppressing portion 26 may be damaged. By providing the first inclined surface 60, however, such damage to the heat conduction suppressing portion 26 can be suppressed. This makes it possible to further improve the reliability of the energy storage module 1.

[0115] Moreover, the third portion 27c of the present embodiment has a third inclined surface 62 on the side facing the thermal conduction suppression portion 26, that is, on the side surface 58 of the third portion 27c facing the first power storage device 2a. The third inclined surface 62 is inclined so as to move away from the thermal conduction suppression portion 26 as it moves from the outside to the inside of the frame portion 24. The third inclined surface 62 is disposed at the end portion of the third portion 27c on the hole 42 side. Thus, the third portion 27c has a tapered portion whose thickness decreases from the outside to the center of the power storage module 1. By providing the third inclined surface 62, it is possible to prevent the thermal conduction suppression portion 26 from being pressed against the corner portion of the third portion 27c due to the expansion of the first power storage device 2a and being damaged. This makes it possible to further improve the reliability of the power storage module 1.

[0116] (Embodiment 5) Except for the shape of the frame 24, the fifth embodiment has a common configuration with the third embodiment. The following description of the fifth embodiment will focus on configurations that are different from the third embodiment, and common configurations will be explained briefly or omitted. FIG. 17 is an enlarged cross-sectional view of a portion of the lower part of the energy storage module according to the fifth embodiment. FIG. 17 shows a schematic diagram of the internal structure of the energy storage device 2.

[0117] The separator 4 included in the power storage module 1 according to the present embodiment has a frame portion 24 and a heat conduction suppression portion 26, similar to the third embodiment. The frame portion 24 is interposed between the first power storage device 2a and the second power storage device 2b, and has a hole 42 extending between the two power storage devices 2 and a locking portion 27 of the heat conduction suppression portion 26. The locking portion 27 has a first portion 27a, a second portion 27b, and a third portion 27c. The heat conduction suppression portion 26 is disposed so as to close the hole 42 and is supported by the frame portion 24. The first portion 27a abuts against a surface 26a of the heat conduction suppression portion 26 facing a direction intersecting with the first direction X. The second portion 27b is interposed between the heat conduction suppression portion 26 and the first power storage device 2a. The third portion 27c is interposed between the heat conduction suppression portion 26 and the second power storage device 2b.

[0118] Further, the second portion 27b of the present embodiment has a second inclined surface 64 on a side facing the first power storage device 2a, i.e., on a side surface of the second portion 27b facing the first power storage device 2a. The second inclined surface 64 inclines so as to move away from the first power storage device 2a from the outside to the inside of the frame portion 24. The second inclined surface 64 is disposed at an end of the second portion 27b on the hole 42 side. Therefore, the second portion 27b has a tapered portion whose thickness decreases from the outside to the center of the power storage module 1.

[0119] Providing the second inclined surface 64 on the second portion 27b makes it possible to prevent the exterior can 10 of the first power storage device 2a from being pressed against the corners of the second portion 27b due to the expansion of the first power storage device 2a. This makes it possible to reduce the risk of damage such as dents being caused to the exterior can 10 or the insulating tape covering the outer surface of the exterior can 10. This makes it possible to further improve the reliability of the power storage module 1.

[0120] Moreover, the third portion 27c of the present embodiment has a fourth inclined surface 66 on a side facing the second power storage device 2b, i.e., on a side surface of the third portion 27c facing the second power storage device 2b. The fourth inclined surface 66 inclines so as to move away from the second power storage device 2b from the outside to the inside of the frame portion 24. The fourth inclined surface 66 is disposed at an end of the third portion 27c on the hole 42 side. Therefore, the third portion 27c has a tapered portion whose thickness decreases from the outside to the center of the power storage module 1.

[0121] Providing the fourth inclined surface 66 on the third portion 27c makes it possible to prevent the exterior can 10 of the second power storage device 2b from being pressed against the corners of the third portion 27c due to the expansion of the second power storage device 2b. This makes it possible to reduce the risk of damage such as dents being caused to the exterior can 10 or the insulating tape covering the outer surface of the exterior can 10. This makes it possible to further improve the reliability of the power storage module 1.

[0122] The above describes the embodiments of the present invention in detail. The above-mentioned embodiments merely show specific examples of implementing the present invention. The contents of the embodiments do not limit the technical scope of the present invention, and many design changes such as changes, additions, and deletions of components are possible within the scope of the invention as defined in the claims. A new embodiment with design changes has the effects of each of the combined embodiments and modifications. In the above-mentioned embodiments, the contents for which such design changes are possible are emphasized by adding notations such as "in this embodiment" and "in this embodiment", but design changes are permitted even in contents without such notations. In addition, any combination of components included in each embodiment is also effective as an aspect of the present invention. The hatching on the cross section of the drawing does not limit the material of the object to which the hatching is added.

[0123] In the energy storage modules 1 of the first and second embodiments, the separator 4 may not include the heat conduction suppressing portion 26. That is, the separator 4 may include only the frame portion 24. The separator 4 may include a flat plate portion without the hole 42, instead of the frame portion 24. In this case, the separation region 48 is disposed in a region of the flat plate portion that overlaps with the joint portion 20 as viewed from the first direction X. The flat plate portion may include the entire region except for the separation region 48 as the contact region 46, but it is preferable that only a region that overlaps with the peripheral portion of the long side surface 10b as viewed from the first direction X constitutes the contact region 46. That is, it is preferable that a gap 52 is formed in a region that overlaps with the electrode body 14 as viewed from the first direction X. The separator 4 may not include the wall portion 28.

[0124] The number of power storage devices 2 included in the power storage module 1 is not particularly limited. The structure of each part of the power storage module 1, including the shape of the wall portion 28 of the separator 4 and the fastening structure between the end plates 6 and the restraining members 8, is not particularly limited. The power storage module 1 may include a bus bar plate. The bus bar plate is a plate-like member that is disposed to face and cover the upper surfaces of the multiple power storage devices 2. The shape of the opening 12 of the exterior can 10 may be a quadrilateral shape such as a square, a polygonal shape other than a quadrilateral, or the like.

[0125] The power storage modules 1 according to the third to fifth embodiments may be modified as follows: (Modification 1) Fig. 18 is an enlarged cross-sectional view of a portion of the lower part of the electricity storage module according to Modification 1. Fig. 18 shows a schematic internal structure of the electricity storage device 2. The locking portion 27 of Modification 1 has a first portion 27a and a second portion 27b, but does not have a third portion 27c. Even when the locking portion 27 does not have the third portion 27c, a gap 52 can be provided between the heat conduction suppressing portion 26 and the first electricity storage device 2a. Therefore, as described in the third embodiment, the amount of compression of the heat conduction suppressing portion 26 due to the expansion of each exterior can 10 can be reduced.

[0126] 18 shows second portion 27b having first inclined surface 60 (corresponding to the structure in which third portion 27c is omitted in embodiment 4), but is not particularly limited to this structure. Second portion 27b may have second inclined surface 64 (corresponding to the structure in which third portion 27c is omitted in embodiment 5), or may not have first inclined surface 60 and second inclined surface 64 (corresponding to the structure in which third portion 27c is omitted in embodiment 3).

[0127] (others) The second portion 27b may have both the first inclined surface 60 and the second inclined surface 64. Similarly, the third portion 27c may have both the third inclined surface 62 and the fourth inclined surface 66. Moreover, the first inclined surface 60 to the fourth inclined surface 66 can be combined in any manner. The second portion 27b and / or the third portion 27c may not be provided around the entire circumference of the frame portion 24. That is, the second portion 27b and / or the third portion 27c may be provided intermittently around the hole 42. Similarly, the first inclined surface 60 to the fourth inclined surface 66 may also be provided intermittently around the hole 42. Moreover, the first portion 27a to the third portion 27c may not be integral with each other, and may be spaced apart from each other by a predetermined distance.

[0128] In the third to fifth embodiments and the first modification, the first power storage device 2a and the second power storage device 2b are any two of the multiple power storage devices 2. Although it is preferable that all of the separators 4 included in the power storage module 1 have the structure described in each embodiment or the first modification, it is sufficient that at least one separator 4 has the structure.

[0129] The number of power storage devices 2 included in the power storage module 1 is not particularly limited. The structure of each part of the power storage module 1, including the shape of the wall portion 28 of the separator 4 and the fastening structure between the end plates 6 and the restraining members 8, is not particularly limited. The power storage module 1 may include a bus bar plate. The bus bar plate is a plate-like member that is disposed to face and cover the upper surfaces of the multiple power storage devices 2. The shape of the opening 12 of the exterior can 10 may be a quadrilateral shape such as a square, a polygonal shape other than a quadrilateral, or the like. [Industrial Applicability]

[0130] The present invention can be used in an electricity storage module. [Explanation of symbols]

[0131] 1 power storage module, 2 power storage device, 2a first power storage device, 2b second power storage device, 4 separator, 10 exterior can, 12 opening, 16 sealing plate, 20 joint part, 24 frame part, 26 heat conduction suppressing part, 27 locking part, 27a first part, 27b second part, 27c third part, 42 hole, 46 contact area, 48 separation area, 48a slope, 60 first slope, 62 third slope, 64 second slope, 66 fourth slope.

Claims

1. a first power storage device and a second power storage device arranged in a first direction; a separator disposed between the first power storage device and the second power storage device to provide insulation between the two power storage devices; The separator has a frame portion and a heat conduction suppressing portion, the frame portion is interposed between the first power storage device and the second power storage device and has a hole extending between the two power storage devices and a locking portion for the heat conduction suppressing portion; the heat conduction suppressing portion is disposed so as to close the hole and is supported by the frame portion, the engaging portion has a first portion that abuts against a surface of the thermal conduction suppressing portion that faces a direction intersecting the first direction, and a second portion that is interposed between the thermal conduction suppressing portion and the first power storage device. Energy storage module.

2. the second portion has a first inclined surface on a side facing the heat conduction suppressing portion, the first inclined surface being inclined so as to move away from the heat conduction suppressing portion as it moves from the outer side to the inner side of the frame portion; The energy storage module according to claim 1 .

3. the second portion has a second inclined surface on a side facing the first power storage device, the second inclined surface being inclined so as to move away from the first power storage device as it moves from the outer side to the inner side of the frame portion, The energy storage module according to claim 1 or 2.

4. the engaging portion has a third portion interposed between the heat conduction suppressing portion and the second power storage device; The energy storage module according to claim 1 .

5. the third portion has a third inclined surface on a side facing the heat conduction suppressing portion, the third inclined surface being inclined so as to move away from the heat conduction suppressing portion from the outer side toward the inner side of the frame portion; The power storage module according to claim 4 .

6. the third portion has a fourth inclined surface on a side facing the second power storage device, the fourth inclined surface being inclined so as to move away from the second power storage device as it moves from the outer side to the inner side of the frame portion, The energy storage module according to claim 4 or 5.

7. Each of the power storage devices includes an exterior can having an opening, a sealing plate that closes the opening, and a joint between the exterior can and the sealing plate, the frame portion has a contact region that comes into contact with a surface of the outer can facing the first direction, and a separation region that overlaps with the joint portion when viewed from the first direction and is recessed in a direction away from the outer can with respect to the contact region. The energy storage module according to claim 1 .

8. the separation region overlaps with the entirety of the joint portion in a second direction in which the sealing plate extends as viewed from the first direction; The power storage module according to claim 7.

9. The separation region overlaps with the entire joint portion in the thickness direction of the sealing plate. The electricity storage module according to claim 7 or 8.

10. the separation region protrudes beyond the sealing plate toward a surface of the exterior can facing the sealing plate, The energy storage module according to claim 7 .

Images