Method for manufacturing an energy storage device, and restraint device

Abstract

The present invention provides a method for manufacturing an energy storage device that can suppress the decrease in surface pressure experienced by the laminated body in the laminated unit after the aging process. [Solution] The method for manufacturing the energy storage device comprises an assembly step and an aging step. The assembly step is a step of assembling the laminated unit 100. After the assembly step, the surface pressure applied from the first restraint plate 14 to the first main surface 3 of the laminated body 2 via the first elastic sheet 12 is 40 kPa or more and 160 kPa or less. The aging step is an aging treatment of the laminated unit 100. After the aging step, the surface pressure applied from the first restraint plate 14 to the first main surface 3 of the laminated body 2 via the first elastic sheet 12 is maintained at 40 kPa or more and 160 kPa or less.

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing an energy storage device and a restraint.

Background Art

[0002] For example, Japanese Patent Application Laid-Open No. 2019-216073 discloses an energy storage device including a laminate and a restraint. The laminate has a plurality of energy storage modules laminated in a stacking direction H. The restraint is formed of an elastic sheet, a pair of restraint plates, and a pair of connecting members. The elastic sheet is disposed on both end faces of the laminate in the stacking direction H. Each of the pair of restraint plates is disposed on each of the elastic sheets disposed on both end faces of the laminate in the stacking direction H. The pair of connecting members restrain the pair of restraint plates in the stacking direction H of the laminate.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The inventor of the present application considered applying the restraint disclosed in Japanese Patent Application Laid-Open No. 2019-216073 to a laminate unit. Note that the laminate unit is a form in the manufacturing process of the energy storage device.

[0005] The laminated unit comprises a laminate and a restraint. The laminate has a plurality of energy storage modules stacked in the stacking direction H. Each energy storage module has a unit battery. Here, a unit battery is, for example, a lithium-ion secondary battery. Furthermore, an energy storage module and a unit battery that have not undergone battery activation work and are not yet put into practical use are referred to as a pre-energy storage module and a pre-unit battery, respectively. The restraint in the laminated unit is formed from an elastic sheet, a pair of restraint plates, and a pair of connecting members. The elastic sheet is arranged on both end faces of the laminate in the stacking direction H. Each of the pair of restraint plates is arranged on each of the elastic sheets arranged on both end faces of the laminate in the stacking direction H. The pair of connecting members restrain the pair of restraint plates in the stacking direction H of the laminate. In this configuration, the laminate is subjected to pressure from the elastic sheet in the stacking direction H. Here, the laminated unit is held at a constant temperature for a certain period of time under conventionally known conditions during the aging process of the battery activation work. Conventional known conditions include, for example, the laminate unit being held at 45-80°C for about 10-100 hours. The inventors of this application have confirmed that, due to aging, the surface pressure in the lamination direction H that the laminate receives from the restraint decreases, partly due to the softening of the elastic sheet.

[0006] This disclosure was made to solve the above problems, and its purpose is to provide a method for manufacturing an energy storage device that can suppress the decrease in surface pressure on the laminate in the laminate unit after the aging process. [Means for solving the problem]

[0007] The method for manufacturing the energy storage device of this disclosure comprises an assembly step and an aging step. The assembly step is a step of assembling a laminated unit. The laminated unit comprises a laminate including at least one energy storage module stacked in the stacking direction and a restraint for restraining the laminate. The laminate has a first main surface and a second main surface arranged in the stacking direction, and a circumferential surface connecting the first main surface and the second main surface. The circumferential surface has a first side surface and a second side surface arranged in the width direction. The restraint includes a first elastic sheet provided on the first main surface, a first restraint plate provided on the first elastic sheet, a second elastic sheet provided on the second main surface, a second restraint plate provided on the second elastic sheet, a first connecting member provided on the first side surface and connecting the first restraint plate and the second restraint plate, and a second connecting member provided on the second side surface and connecting the first restraint plate and the second restraint plate. After the assembly process, the surface pressure applied to the first main surface of the laminate from the first restraint plate via the first elastic sheet is 40 kPa or more and 160 kPa or less. The aging process involves aging the laminate unit. After the aging process, the surface pressure applied to the first main surface of the laminate from the first restraint plate via the first elastic sheet is maintained at 40 kPa or more and 160 kPa or less.

[0008] In energy storage devices manufactured in this manner, the laminated body of the laminated unit is subjected to a surface pressure of 40 kPa or more and 160 kPa or less from the restraint before and after the aging process. As a result, it is possible to suppress the decrease in the surface pressure that the laminated body of the laminated unit receives from the restraint due to aging.

[0009] The material of the first elastic sheet in the manufacturing method of the energy storage device of this disclosure may be foamed urethane. By selecting foamed urethane as the material of the elastic sheet, the decrease in surface pressure due to aging can be suppressed.

[0010] The restraint of the present disclosure restrains a laminate including at least one energy storage module stacked in the stacking direction. The laminate has a first main surface and a second main surface arranged in the stacking direction, and a circumferential surface connecting the first main surface and the second main surface. The circumferential surface has a first side surface and a second side surface arranged in the width direction. The restraint includes a first elastic sheet provided on the first main surface, a first restraint plate provided on the first elastic sheet, a second elastic sheet provided on the second main surface, a second restraint plate provided on the second elastic sheet, a first connecting member provided on the first side surface and connecting the first restraint plate and the second restraint plate, and a second connecting member provided on the second side surface and connecting the first restraint plate and the second restraint plate. The surface pressure applied from the first restraint plate to the first main surface of the laminate via the first elastic sheet is 40 kPa or more and 160 kPa or less.

[0011] The material of the first elastic sheet in the restraint device of this disclosure may be foamed urethane. [Effects of the Invention]

[0012] According to the method for manufacturing an energy storage device described herein, it is possible to suppress the decrease in surface pressure received by the laminated body unit from the restraint device due to aging. [Brief explanation of the drawing]

[0013] [Figure 1] A schematic perspective view of the laminated unit according to this embodiment is shown. [Figure 2] This shows an exploded perspective view of the laminated unit according to this embodiment. [Figure 3] This example shows the relationship between the initial restraining surface pressure P and the surface pressure drop due to aging in the laminated unit according to this embodiment. [Figure 4] This shows the change in the thickness of the first elastic sheet over time after the laminated unit according to this embodiment has undergone an aging process. [Figure 5] This diagram shows a schematic representation of the arrangement process in the manufacturing method of the energy storage device according to this embodiment. [Figure 6]The schematic diagram of the compression process in the manufacturing method of the power storage device according to the present embodiment is shown. [Figure 7] The schematic diagram of the connection process in the manufacturing method of the power storage device according to the present embodiment is shown.

Embodiments for Carrying Out the Invention

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and their descriptions will not be repeated.

[0015] FIG. 1 shows a schematic perspective view of a laminate unit according to the present embodiment. The laminate unit is one form during the manufacturing process of the power storage device. Note that the stacking direction H shown in FIG. 1 indicates the stacking direction H of the power storage modules 10 included in the laminate 2 described later. The width direction W indicates the width direction of the laminate unit 100. The length direction L indicates the length direction of the laminate unit 100.

[0016] The laminate unit 100 includes a restraint 1 and a laminate 2. The restraint 1 includes a first restraint plate 14, a second restraint plate 15, a first elastic sheet 12, a second elastic sheet 13, a first connecting member 23a, and a second connecting member 23b. The restraint 1 restrains the laminate 2 in the stacking direction H.

[0017] FIG. 2 shows an exploded perspective view of the laminate unit. The laminate 2 is formed, for example, in a rectangular parallelepiped shape. The laminate 2 has a first main surface 3, a second main surface 4, and a peripheral surface 5. The first main surface 3 and the second main surface 4 are both end faces of the laminates arranged in the stacking direction H. The peripheral surface 5 is a surface connecting the outer peripheral edge of the first main surface 3 and the outer peripheral edge of the second main surface 4. The peripheral surface 5 has a first side surface 6a, a second side surface 6b, a first end face 7a, and a second end face 7b. The first side surface 6a and the second side surface 6b are arranged in the width direction W. The first end face 7a and the second end face 7b are arranged in the length direction L. The first end face 7a connects the first side surface 6a and the second side surface 6b. The second end face 7b connects the first side surface 6a and the second side surface 6b.

[0018] When the laminate 2 is viewed in plan from a position away from the laminate 2 in the stacking direction H, the laminate 2 is formed in a rectangular shape formed by a pair of long sides 8 and a pair of short sides 9. The long side 8 is longer than the short side 9.

[0019] The laminate 2 includes at least one power storage module 10 and a plurality of inclusions 11. The power storage module 10 includes a plurality of unit cells (not shown) and a frame body. The unit cell is, for example, a bipolar battery. Each of the plurality of unit cells adjacent in the stacking direction H is electrically connected. The unit cell has a first current collector plate, a negative electrode sheet, a separator, a positive electrode sheet, and a second current collector plate. The plurality of unit cells are stacked such that the second current collector plate and the first current collector plate are adjacent in the stacking direction H. The frame body is formed in a frame shape and is formed to extend in the stacking direction H. The frame body is formed to surround the plurality of stacked unit cells.

[0020] The inclusions 11 are stacked in the stacking direction H with the power storage module 10 interposed therebetween. The inclusion 11 is formed of a conductive plate and two elastic bodies. The two elastic bodies sandwich the conductive plate and are arranged in the stacking direction H. Note that the conductive plate functions as a support structure member of the elastic body. A conductive sheet is wound around each of the two elastic bodies. The inclusion 11 adjacent to the first elastic sheet 12 or the second elastic sheet 13 may be formed of one elastic body and a conductive plate. In this case, the conductive plate is adjacent to the first elastic sheet 12 or the second elastic sheet 13.

[0021] The first elastic sheet 12 and the second elastic sheet 13 are provided on the first main surface 3 and the second main surface 4, respectively. The material of the first elastic sheet 12 and the second elastic sheet 13 is foamed urethane. When the first elastic sheet 12 is viewed from a position away from it in the lamination direction H, the first elastic sheet 12 is formed in the same shape as the first main surface 3 of the laminate 2. The same applies to the second elastic sheet 13. Here, a first insulating sheet 12a may be placed between the first elastic sheet 12 and the first restraint plate 14. Similarly, a second insulating sheet 13a may be placed between the second elastic sheet 13 and the second restraint plate 15. The first insulating sheet 12a and the second insulating sheet 13a are sheet-like members formed from insulating materials. When the first insulating sheet 12a is viewed from a position away from the first restraint plate 14 in the lamination direction H, the first insulating sheet 12a is formed to cover the entire first elastic sheet 12. When the second insulating sheet 13a is viewed from a position away from the second restraint plate 15 in the lamination direction H, the second insulating sheet 13a is formed to cover the entire second elastic sheet 13.

[0022] The first restraint plate 14 and the second restraint plate 15 are stacked in the stacking direction H with the laminate 2 sandwiched between them. More specifically, the first restraint plate 14 is provided on the first elastic sheet 12, and the second restraint plate 15 is provided on the second elastic sheet 13. Since the second restraint plate 15 has substantially the same configuration as the first restraint plate 14, the configuration of the first restraint plate 14 will be described primarily.

[0023] The first restraint plate 14 is a plate-shaped member. When the first restraint plate 14 is viewed from a position away from it in the stacking direction H, it has a rectangular shape formed by a pair of long sides 16 and a pair of short sides 17, covering the laminate 2. The long sides 16 are the same length as the long sides 8. The short sides 17 are longer than the short sides 9.

[0024] The pair of short sides 17 include the first end side 17a and the second end side 17b. The first end side 17a and the second end side 17b are spaced apart in the length direction L.

[0025] The first restraint plate 14 has a first outer surface 21a, a first inner surface 22a, a first side portion 81a, and a second side portion 81b. The first outer surface 21a and the first inner surface 22a are spaced apart in the stacking direction H. The first inner surface 22a is positioned opposite the first main surface 3. The first side portion 81a and the second side portion 81b are spaced apart in the width direction W. A first notch 18a is formed in the first side portion 81a. A second notch 18b is formed in the second side portion 81b.

[0026] Since the first notch 18a and the second notch 18b have substantially the same configuration, the first notch 18a will be described primarily. The first notch 18a penetrates the first restraint plate 14 in the stacking direction H. The first notch 18a is formed to be arranged in the length direction L along the long side 16 of the first restraint plate 14. When the first notch 18a is viewed from a position away from the first notch 18a in the stacking direction H, the first notch 18a is defined by an arc 19 and a pair of straight lines 20 connected to the ends of the arc 19. The other ends of the pair of straight lines 20 intersect the long side 16. The distance between the pair of straight lines 20 is equal to the diameter of the circle forming the arc 19.

[0027] The second restraint plate 15 has substantially the same configuration as the first restraint plate 14. Like the first restraint plate 14, the second restraint plate 15 has a third end edge 17c, a fourth end edge 17d, a second outer surface 21b, a second inner surface 22b, a third side portion 81c, and a fourth side portion 81d. A third notch 18c is formed in the third side portion 81c. A fourth notch 18d is formed in the fourth side portion 81d.

[0028] When the second restraint plate 15 and the first restraint plate 14 are viewed in plan from a position separated from the second restraint plate 15 in the stacking direction H, the first notch 18a is positioned to overlap with the third notch 18c, and the second notch 18b is positioned to overlap with the fourth notch 18d.

[0029] The first restraint plate 14 has thin plates 71 and 72 and a rib 73. The rib 73 is formed to extend in the width direction W. The rib 73 is arranged with a gap in the length direction L, sandwiching the first notch 18a and the second notch 18b between them. The thin plates 71 and 72 are each formed to cover the rib 73. The thin plates 71 and 72 are arranged with a gap in between, sandwiching the rib 73, in the stacking direction H. Compared to the thin plate 71, the thin plate 72 is positioned on the side of the laminate 2 in the stacking direction H.

[0030] The second restraint plate 15 has thin plates 76, 77 and ribs 78. The ribs 78 are formed to extend in the width direction W. The ribs 78 are arranged with a gap in the length direction L, sandwiching the third notch 18c and the fourth notch 18d between them. The thin plates 76 and 77 are each formed to cover the ribs 78. The thin plates 76 and 77 are arranged with a gap in between, sandwiching the ribs 78, in the stacking direction H. Compared to the thin plate 76, the thin plate 77 is positioned on the side of the laminate 2 in the stacking direction H.

[0031] The first connecting member 23a and the second connecting member 23b are arranged with a gap between them in the width direction W, with the laminate 2 in between. The first connecting member 23a is provided on the first side surface 6a side. The second connecting member 23b is provided on the second side surface 6b side. The first connecting member 23a and the second connecting member 23b connect the first restraint plate 14 and the second restraint plate 15, respectively, in the lamination direction H. Since the second connecting member 23b has substantially the same configuration as the first connecting member 23a, the first connecting member 23a will be described in detail.

[0032] The first connecting member 23a has a frame 25a and a plurality of column members 38a. Frame 25a is formed to extend in the longitudinal direction L. Frame 25a has an upper frame 26a and a lower frame 32a. The upper frame 26a and the lower frame 32a are spaced apart in the stacking direction H.

[0033] When the upper frame 26a is viewed from above from a position away from it in the stacking direction H, the upper frame 26a is formed to extend in the length direction L. The length L of the upper frame 26a is equal to the long side 16 of the first restraint plate 14. That is, the upper frame 26a is formed to extend in the length direction L from the first end side 17a to the second end side 17b. When the upper frame 26a is viewed from above from a position away from it in the length direction L, the upper frame 26a is formed to extend in the width direction W and is rectangular in shape. The upper frame 26a has an outer surface 27a and an inner surface 28a. The outer surface 27a and the inner surface 28a are end faces arranged in the stacking direction H. The inner surface 28a is located on the side of the lower frame 32a.

[0034] When the lower frame 32a is viewed from above from a position away from it in the stacking direction H, the lower frame 32a is formed to extend in the length direction L. The length L of the lower frame 32a is equal to the long side 16 of the second restraint plate 15. That is, the lower frame 32a is formed to extend in the length direction L from the third end side 17c to the fourth end side 17d. When the lower frame 32a is viewed from above from a position away from it in the length direction L, the lower frame 32a is formed to extend in the width direction W and is rectangular in shape. The lower frame 32a has an outer surface 33a and an inner surface 34a. The outer surface 33a and the inner surface 34a are end faces arranged in the stacking direction H. The inner surface 34a is located on the side of the upper frame 26a.

[0035] Frame 25a is positioned in contact with the first restraint plate 14 and the second restraint plate 15. More specifically, the inner surface 28a of the upper frame 26a is positioned in contact with the first outer surface 21a. Similarly, the inner surface 34a of the lower frame 32a is positioned in contact with the second outer surface 21b.

[0036] The column members 38a are formed to extend in the stacking direction H. Multiple column members 38a are formed to have the same length in the stacking direction H. Multiple column members 38a are arranged with intervals in the length direction L. The column members 38a are positioned to pass through the first notch 18a and the third notch 18c, and connect the upper frame 26a and the lower frame 32a.

[0037] The second connecting member 23b has substantially the same configuration as the first connecting member 23a. The second connecting member 23b has a frame 25b and a plurality of column members 38b. The frame 25b has an upper frame 26b and a lower frame 32b. The upper frame 26b has an outer surface 27b and an inner surface 28b. The lower frame 32b has an outer surface 33b and an inner surface 34b. The frame 25b is positioned in contact with the first restraint plate 14 and the second restraint plate 15. More specifically, the inner surface 28b of the upper frame 26b is positioned in contact with the first outer surface 21a. Similarly, the inner surface 34b of the lower frame 32b is positioned in contact with the second outer surface 21b. The column members 38b are positioned to pass through the second notch 18b and the fourth notch 18d, and connect the upper frame 26b and the lower frame 32b.

[0038] In the above embodiment, the restraint 1 restrains the laminate 2 in the stacking direction H. A first elastic sheet 12 is placed between the first restraint plate 14 and the laminate 2. A second elastic sheet 13 is placed between the second restraint plate 15 and the laminate 2.

[0039] In this configuration, the restraint device 1 can restrain the laminate 2 in the lamination direction H. Figure 3 shows the initial restraint surface pressure P [kPa] and the surface pressure drop ΔP [kPa] due to aging. The initial restraint surface pressure P is the surface pressure that the laminate 2 in the laminate unit 100 receives from the restraint device 1 before the aging process. More specifically, the initial restraint surface pressure P is the surface pressure applied from the first restraint plate 14 to the first main surface 3 of the laminate 2 via the first elastic sheet 12. The material of the first elastic sheet 12 and the material of the second elastic sheet 13 are foamed urethane, and the laminate unit 100 was maintained at 70°C during the aging process. Figure 3 shows that the surface pressure drop ΔP due to aging increases as the initial restraint surface pressure P increases. Next, Figure 4 shows the change in the thickness t of the first elastic sheet 12 over time after the aging process of the laminate unit 100 in which the laminate 2 was restrained at 40 kPa in the lamination direction H. Immediately after aging (at time 0 in Figure 3), the thickness t of the elastic sheet is deformed to be thinner than the original thickness t0. Subsequently, the thickness of the elastic sheet recovers over time. In other words, it can be inferred that a decrease in surface pressure occurs due to the softening of the first elastic sheet 12 by aging, and that this decrease in surface pressure is resolved over time.

[0040] In the battery activation process, it is necessary to apply appropriate surface pressure to the unit battery in the stacking direction H, but the initial restraining surface pressure needs to be set to an appropriate value that takes into account the decrease in surface pressure due to aging. From Figures 3 and 4, it is appropriate to set the initial restraining surface pressure P to 40kPa or more and 160kPa. That is, the restraining device 1 restrains the laminate 2 in the stacking direction H such that the surface pressure applied to the first elastic sheet 12 from the first main surface 3 of the laminate 2 and the surface pressure applied to the second elastic sheet 13 from the second main surface 4 of the laminate 2 are each 40kPa or more and 160kPa or less. Furthermore, it is preferable that the material of the first elastic sheet 12 and the material of the second elastic sheet 13 of the restraining device 1 are foamed urethane. More specifically, Cell Damper (registered trademark) BF-300 and SlimFlex (registered trademark) TR-24. Such a restraining device 1 can suppress the decrease in surface pressure that the laminate 2 in the laminate unit 100 receives from the restraining device 1 due to aging. <Manufacturing method for energy storage devices> Next, a method for manufacturing an energy storage device will be described. More specifically, an example of a method for manufacturing a laminated unit 100, which is one form in the manufacturing process of an energy storage device, will be described. The method for manufacturing the laminated unit 100 comprises, in order, an assembly step and an aging step. The assembly step is the step of assembling the laminated unit. More specifically, the assembly step may include some or all of a preparation step, a placement step, a compression step, a measurement step, a linking step, and an unloading step. Details of each step are described below.

[0041] In the preparation step, the laminate 2, the first elastic sheet 12, the second elastic sheet 13, the first restraint plate 14, the second restraint plate 15, the first connecting member 23a, and the second connecting member 23b are prepared.

[0042] Figure 5 shows the arrangement process. In the arrangement process, the first elastic sheet 12 and the second elastic sheet 13 are placed on the first main surface 3 and the second main surface 4 of the laminate 2, respectively. Then, the first restraining plate 14 and the second restraining plate 15 are placed on the first elastic sheet 12 and the second elastic sheet 13, respectively, in the lamination direction H. The laminate 2, the first elastic sheet 12, the second elastic sheet 13, the first restraining plate 14, and the second restraining plate 15 after the arrangement process are referred to as the unrestrained body 101.

[0043] Figure 6 shows a diagram of the compression process. In the compression process, the unrestrained body 101 is compressed in the stacking direction H. Specifically, the first restraining plate 14 and the second restraining plate 15 are each pressurized in the stacking direction H toward the center of the stacked body 2. The applied pressure is, for example, 40 kPa or more and 160 kPa or less. The pressurization is applied, for example, using a press machine 99.

[0044] In the measurement process, the distance between the first outer surface 21a and the second outer surface 21b of the unrestrained body 101, which has been compressed with a predetermined pressure in the compression process, is measured. The distance between the first outer surface 21a and the second outer surface 21b is called the restraint height T1.

[0045] Figure 7 shows the connection process. In the connection process, the first connecting member 23a, which includes a column member 38a whose length in the stacking direction H is the restraint height T1, connects the first restraint plate 14 and the second restraint plate 15 on the first side surface 6a side. Similarly, the second connecting member 23b, which includes a column member 38b whose length in the stacking direction H is the restraint height T1, connects the first restraint plate 14 and the second restraint plate 15 on the second side surface 6b side.

[0046] More specifically, the first connecting member 23a is attached so that the upper frame 26a overlaps the first restraint plate 14 and the lower frame 32a overlaps the second restraint plate 15. In addition, the column member 38a is attached from the width direction W toward the first side surface 6a of the laminate 2 so that it passes through the first notch 18a and the third notch 18c formed in the first restraint plate 14 and the second restraint plate 15. As a result, the first connecting member 23a is provided on the first side surface 6a side. Similarly, the second connecting member 23b is attached so that the upper frame 26b overlaps the first restraint plate 14 and the lower frame 32b overlaps the second restraint plate 15. In addition, the column member 38b is attached from the width direction W toward the second side surface 6b of the laminate 2 so that it passes through the second notch 18b and the fourth notch 18d formed in the first restraint plate 14 and the second restraint plate 15. As a result, the second connecting member 23b is provided on the second side surface 6b. The first connecting member 23a and the second connecting member 23b are attached in the width direction W with the laminate 2 in between, from positions opposite each other with respect to the center of the laminate 2.

[0047] In the unloading process, the pressure applied to the unrestrained body 101 by the press machine 99 is removed.

[0048] In the aging process, the laminated unit 100 is subjected to an aging treatment. Here, the aging process is one of the processes for activating the batteries (not shown) of the energy storage module 10. In the aging treatment, the laminated unit 100 is held at a constant temperature for a certain period of time under conventionally known conditions. Conventionally known conditions include, for example, being held at 45 to 80°C for about 10 to 100 hours.

[0049] In the pressurizing step of the manufacturing method for the laminated unit 100 in the above embodiment, a pressurizing force of 40 kPa or more and 160 kPa or less is applied to the first restraint plate 14 and the second restraint plate 15 by, for example, a press machine 99. At this time, the distance between the first outer surface 21a of the first restraint plate 14 and the second outer surface 21b of the second restraint plate 15 is the restraint height T1. In the connecting step, the first restraint plate 14 and the second restraint plate 15 are connected by a first connecting member 23a having a column member 38a whose length in the stacking direction H is the restraint height T1. The same applies to the second connecting member 23b. As a result, the distance between the first outer surface 21a and the second outer surface 21b in the stacking direction H is maintained at the restraint height T1 by the first connecting member 23a and the second connecting member 23b. Consequently, the pressurizing force applied to the laminated body 2 in the pressurizing step is maintained even after the pressurizing force by the press machine 99 is removed. In other words, the surface pressure applied from the first restraint plate 14 to the first main surface 3 via the first elastic sheet 12 after the assembly process but before the aging process is 40 kPa or more and 160 kPa or less. In a laminated unit 100 manufactured by this manufacturing method, the surface pressure applied from the first restraint plate 14 to the first main surface 3 via the first elastic sheet 12 is maintained at 40 kPa or more and 160 kPa or less even after the aging process.

[0050] The embodiments disclosed herein should be considered in all respects to be illustrative and not restrictive. The scope of this disclosure is indicated by the claims rather than by the description of the embodiments above, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Explanation of Symbols]

[0051] 1 Restraint, 2 Laminate, 3 First main surface, 4 Second main surface, 5 Surrounding surface, 6a First side surface, 6b Second side surface, 7a First end surface, 7b Second end surface, 8 Long side, 9 Short side, 10 Energy storage module, 11 Inclusion, 12 First elastic sheet, 12a First insulating sheet, 13 Second elastic sheet, 13a Second insulating sheet, 14 First restraint plate, 15 Second restraint plate, 16 Long side, 17 Short side, 17a First end surface, 17b Second end surface, 17c Third end surface, 17d Fourth end surface, 18a First notch, 18b Second notch, 18c Third notch, 18d Fourth notch, 19 Arc, 20 Straight line, 21a First outer surface, 21b Second outer surface, 22a First inner surface, 22b Second inner surface, 23a 1st connecting member, 23b 2nd connecting member, 25a Frame, 25b Frame, 26a Upper frame, 26b Upper frame, 27a Outer surface, 27b Outer surface, 28a Inner surface, 28b Inner surface, 32a Lower frame, 32b Lower frame, 33a, 33b Outer surface, 34a, 34b Inner surface, 38a, 38b Column members, 71, 72 Thin plates, 73 Ribs, 76, 77 Thin plates, 78 Ribs, 81a First side, 81b Second side, 81c Third side, 81d Fourth side, 99 Press machine, 100 Laminated unit, 101 Unrestrained body.

Claims

1. A method for manufacturing an energy storage device, comprising an assembly process and an aging process, The assembly process is a process of assembling a laminated unit, The laminated unit comprises a laminate including at least one energy storage module stacked in the stacking direction, and a restraining device for restraining the laminate. The laminate has a first main surface and a second main surface arranged in the stacking direction, and a circumferential surface connecting the first main surface and the second main surface. The circumferential surface has a first side surface and a second side surface arranged in the width direction, The aforementioned restraint device is The first elastic sheet provided on the first main surface, The first restraint plate provided on the first elastic sheet, The second elastic sheet provided on the second main surface, The second restraint plate provided on the second elastic sheet, A first connecting member provided on the first side surface and connecting the first restraint plate and the second restraint plate, It includes a second connecting member provided on the second side surface and connecting the first restraint plate and the second restraint plate, After the assembly process, the surface pressure applied from the first restraint plate to the first main surface of the laminate via the first elastic sheet is 40 kPa or more and 160 kPa or less. The aging process involves aging the laminated unit, A method for manufacturing an energy storage device, wherein, after the aging process, the surface pressure applied from the first restraining plate to the first main surface of the laminate via the first elastic sheet is maintained at 40 kPa or more and 160 kPa or less.

2. The method for manufacturing an energy storage device according to claim 1, wherein the material of the first elastic sheet is foamed urethane.

3. A restraining device for restraining a laminate including at least one energy storage module stacked in the stacking direction, The laminate has a first main surface and a second main surface arranged in the stacking direction, and a circumferential surface connecting the first main surface and the second main surface. The circumferential surface has a first side surface and a second side surface arranged in the width direction, The aforementioned restraint device is The first elastic sheet provided on the first main surface, The first restraint plate provided on the first elastic sheet, The second elastic sheet provided on the second main surface, The second restraint plate provided on the second elastic sheet, A first connecting member provided on the first side surface and connecting the first restraint plate and the second restraint plate, It includes a second connecting member provided on the second side surface and connecting the first restraint plate and the second restraint plate, A restraint device wherein the surface pressure applied from the first restraint plate to the first main surface of the laminate via the first elastic sheet is 40 kPa or more and 160 kPa or less.

4. The restraint device according to claim 3, wherein the material of the first elastic sheet is foamed urethane.

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