Energy storage element unit

Abstract

To provide a power storage element unit which can permit thermal expansion of a resin.SOLUTION: A power storage element unit includes a storage box having a plurality of wall parts, and a plurality of power storage element modules stored in the storage box. At least one of the plurality of wall parts is composed of a laminate including a resin plate and a metal plate. The resin plate is provided with one of a plurality of through holes into which a shaft part of a screw is inserted and a plurality of screw holes on which the shaft part to which the plurality of through holes are inserted is screwed, and the metal plate is provided with the other of the plurality of through holes or the plurality of screw holes. The plurality of through holes includes one reference through hole and a plurality of wide through holes. Each of the plurality of wide through holes has a width larger than the diameter of the reference through hole, in a direction at which each of the wide through holes and the reference through hole are aligned.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to an energy storage element unit.

Background Art

[0002] For example, as disclosed in Patent Document 1, an energy storage element unit having a plurality of energy storage element modules is known. The energy storage element unit includes a storage box that houses the plurality of energy storage element modules together with the plurality of energy storage element modules.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] There have been cases where it is required to use resin as the material of the storage box of the energy storage element unit. When resin is used as the material of the storage box, it is assumed that the resin is heated and thermally expanded by the heat generation of the energy storage element modules housed inside the storage box. For this reason, there has been a demand for an energy storage element unit that can allow the thermal expansion of the resin while using resin as the material of the storage box.

[0005] The present disclosure has been made in consideration of such circumstances, and an object thereof is to provide an energy storage element unit that can allow the thermal expansion of the resin while using resin as the material of the storage box.

Means for Solving the Problems

[0006] The energy storage element unit according to the present disclosure is a storage box having a plurality of wall portions, and a plurality of energy storage element modules housed in the storage box, and is an energy storage element unit comprising At least one of the aforementioned plurality of wall portions is composed of a laminate including a resin plate and a metal plate, The resin plate is provided with either a plurality of through holes through which the shaft of a screw passes, or a plurality of screw holes through which the shaft passed through the plurality of through holes is screwed in, and the metal plate is provided with the other of the plurality of through holes or the plurality of screw holes, The plurality of through holes include one standard through hole and a plurality of wide through holes, Each of the plurality of wide through-holes has a width greater than the diameter of the reference through-hole in the direction in which each of the wide through-holes is aligned with the reference through-hole.

[0007] In the energy storage element unit according to this disclosure, The reference through-hole may fix the position of the shaft portion that passes through the reference through-hole.

[0008] In the energy storage element unit according to this disclosure, The wall portion, which is made up of the laminate, has a pair of first sides extending in a first stretching direction and a pair of second sides extending in a second stretching direction perpendicular to the first stretching direction. The aforementioned plurality of wide through holes include a first wide through hole, a second wide through hole, and a third wide through hole. The first wide through-hole and the reference through-hole are aligned in the first extension direction, The first wide through-hole has a width greater than the diameter of the reference through-hole in the first extending direction. The second wide through-hole and the reference through-hole are aligned in the second extension direction, The second wide through-hole has a width greater than the diameter of the reference through-hole in the second extending direction. The third wide through-hole and the reference through-hole are located in different positions in the first and second extension directions. The third wide through-hole may have a diameter larger than the diameter of the reference through-hole.

[0009] In the energy storage element unit according to this disclosure, The plurality of wall portions include a bottom wall portion, an upper wall portion facing the bottom wall portion, and a plurality of side wall portions connecting the bottom wall portion and the upper wall portion. At least the plurality of side wall portions among the plurality of wall portions may be composed of the laminate.

[0010] In the energy storage element unit according to the present disclosure, In the side wall portion, the reference through hole may be provided at a position closer to the upper wall portion than the bottom wall portion.

[0011] In the energy storage element unit according to the present disclosure, The plurality of screw holes may be provided in the resin plate, and the plurality of through holes may be provided in the metal plate.

Advantages of the Invention

[0012] According to the present disclosure, it is possible to provide an energy storage element unit that can allow thermal expansion of resin while using resin as a material for the storage box.

Brief Description of the Drawings

[0013] [Figure 1] FIG. 1 is a diagram for explaining an embodiment, and is a perspective view showing an energy storage element unit. [Figure 2] FIG. 2 is a perspective view showing the inside of the energy storage element unit of FIG. 1. [Figure 3] FIG. 3 is a perspective view showing a first side wall portion of the storage box of the energy storage element unit of FIG. 1. [Figure 4] FIG. 4 is a perspective view showing an upper wall portion of the storage box of the energy storage element unit of FIG. 1. [Figure 5] FIG. 5 is a perspective view showing the storage box of the energy storage element unit of FIG. 1. [Figure 6] FIG. 6 is a perspective view showing a resin plate of the first side wall portion of FIG. 3. [Figure 7] FIG. 7 is a partial cross-sectional view showing a part of a cross-section of the first side wall portion along line A-A of FIG. 3. [Figure 8]FIG. 8 is a side view showing a resin plate and a metal plate included in the laminate constituting the first side wall portion of FIG. 3. [Figure 9] FIG. 9 is a partial cross-sectional view showing a part of the first resin plate of the first wall portion and the second resin plate of the second wall portion along the line B-B of FIG. 1. [Figure 10] FIG. 10 is a partial cross-sectional view showing a part of the first resin plate of the first wall portion and the second resin plate of the second wall portion along the line B-B of FIG. 1. [Figure 11] FIG. 11 is a diagram for explaining the characteristics and effects of the first resin plate and the second resin plate. [Figure 12] FIG. 12 is a diagram for explaining the characteristics and effects of the first resin plate and the second resin plate. [Figure 13] FIG. 13 is a perspective view showing the resin plate of the upper wall portion of FIG. 4. [Figure 14] FIG. 14 is a perspective view showing the metal plate of the upper wall portion of FIG. 4. [Figure 15] FIG. 15 is a partial cross-sectional view showing a part of the cross-section of the first decorative wall portion and the second decorative wall portion along the line C-C of FIG. 1. [Figure 16] FIG. 16 is a perspective view showing a power storage element module assembly and a power storage element module arranged in the storage box of the power storage element unit of FIG. 1. [Figure 17] FIG. 17 is a perspective view showing the power storage element module included in the power storage element module assembly of FIG. 16. [Figure 18] FIG. 18 is a perspective view showing a plurality of stacked cells included in the power storage element module of FIG. 17. [Figure 19] FIG. 19 is a perspective view showing one cell shown in FIG. 18.

DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an example of an embodiment of a power storage element unit according to the present disclosure will be described in detail with reference to FIGS. 1 to 19.

[0015] Hereinafter, an embodiment of the present disclosure will be described with reference to the specific example shown in the drawings. Note that, for the sake of illustration and ease of understanding, the scale and aspect ratios of the drawings attached to this specification have been appropriately altered and exaggerated from those of the actual objects.

[0016] Figures 1 to 19 are diagrams illustrating one embodiment according to the present disclosure. Of these, Figure 1 is a perspective view showing the energy storage element unit 10, and Figure 2 is a perspective view showing the inside of the energy storage element unit 10. In Figure 2, the energy storage element unit 10 is shown with the upper wall portion 13b and decorative panel 19, which will be described later, removed. Also, in Figure 2, the resin plate 91 of the side wall portion 13c, which will be described later, is not shown.

[0017] To clarify the directional relationships between drawings, some drawings show arrows indicating the first direction DA, the second direction DB, and the third direction DC as common directions across the drawings. The tip of the arrow corresponds to one side SA1, SB1, and SC1 of each direction DA, DB, and DC. Arrows pointing towards the viewer along the direction perpendicular to the plane of the drawing are indicated by a symbol with an X inside a circle, as shown in Figure 8, for example. Arrows pointing towards the back of the drawing along the direction perpendicular to the plane of the drawing are indicated by a symbol with a dot inside a circle, as shown in Figure 9, for example. Furthermore, in drawings showing components housed in the storage box 11 (e.g., the energy storage element module assembly 15 and the energy storage element module 20), the direction and orientation are shown when they are housed in the storage box 11. Similarly, in drawings showing each component included in the energy storage element module 20 (e.g., the cell 30 and case 18, which will be described later), the direction and orientation are shown when they are incorporated into the energy storage element module 20 housed in the storage box 11.

[0018] In the illustrated example, the first direction DA, the second direction DB, and the third direction DC are perpendicular to each other. Furthermore, the first direction DA is parallel to the vertical direction. One side SA1 in the first direction DA is the lower side in the vertical direction, and the other side opposite to that side in the first direction DA is the upper side in the vertical direction.

[0019] The energy storage element unit 10 is used as a rechargeable secondary battery unit. The illustrated energy storage element unit 10 is applied to buildings such as houses and public facilities, and is electrically connected to the building's wiring to function as a power source for electrical devices installed within the building.

[0020] As shown in Figures 1 and 2, the energy storage element unit 10 comprises a storage box 11 and a plurality of energy storage element modules 20 housed within the storage box 11. The energy storage element unit 10 shown in Figures 1 and 2 further comprises a control module 14 housed within the storage box 11.

[0021] First, let's describe the storage box 11. The storage box 11 has a plurality of wall sections 13. The wall sections 13 form the space for the control module 14 and the energy storage element module 20. In the example shown in Figure 2, the storage box 11 further has a frame section 12 that connects adjacent wall sections 12. The wall sections 13 enclose the space for the control module 14 and the energy storage element module 20.

[0022] The multiple wall sections 13 include a first wall section 13d and a second wall section 13e connected to the first wall section 13d. The first wall section 13d and the second wall section 13e are connected to each other without the use of any other wall sections 13. Any two wall sections 13 included in the multiple wall sections 13 that are connected to each other without the use of any other wall sections 13 can be considered as the first wall section 13d and the second wall section 13e.

[0023] In this embodiment, the multiple wall portions 13 of the storage box 11 include a bottom wall portion 13a, an upper wall portion 13b facing the bottom wall portion 13a, and a plurality of side wall portions 13c connected to the bottom wall portion 13a and the upper wall portion 13b. In the example shown in Figure 1, the storage box 11 has a substantially rectangular parallelepiped shape and the wall portions 13 include a bottom wall portion 13a, an upper wall portion 13b, and four side wall portions 13c. In this case, one of the plurality of side wall portions 13c may form the first wall portion 13d, and another of the plurality of side wall portions 13c may form the second wall portion 13e.

[0024] The bottom wall portion 13a has a pair of long sides 131 and a pair of short sides 132 extending in a direction intersecting the pair of long sides 131. In this embodiment, the bottom wall portion 13a is a substantially rectangular, substantially plate-shaped wall portion 13 located on one side SA1 in the first direction DA. The top wall portion 13b is a substantially rectangular, substantially plate-shaped wall portion 13 facing the bottom wall portion 13a in the first direction DA. The bottom wall portion 13a and the top wall portion 13b each have a pair of long sides 131 extending in the third direction DC and a pair of short sides 132 extending in the second direction DB perpendicular to the third direction DC. The four side wall portions 13c are each a substantially rectangular, substantially plate-shaped wall portion 13 that connect to an edge located on one side of the bottom wall portion 13a and an edge located on one side of the top wall portion 13b.

[0025] In this embodiment, the plurality of side wall portions 13c include a pair of first side wall portions 13c1 connected to a pair of long sides 131 of the bottom wall portion 13a, and a pair of second side wall portions 13c2 connected to a pair of short sides 132 of the bottom wall portion 13a. The first side wall portions 13c1 are connected to the long sides 131 of the bottom wall portion 13a without the need for other wall portions 13. The second side wall portions 13c2 are connected to the short sides 132 of the bottom wall portion 13a without the need for other wall portions 13. In the example shown in Figures 1 and 2, the pair of first side wall portions 13c1 are a pair of side wall portions 13c that face each other in the second direction DB and are parallel to the direction in which the long sides 131 of the bottom wall portion 13a extend (third direction DC). Furthermore, the pair of second side wall portions 13c2 are a pair of side wall portions 13c that face each other in the third direction DC and are parallel to the direction in which the short side 132 of the bottom wall portion 13a extends (second direction DB). In this case, at least one of the pair of first side wall portions 13c1 may form a first wall portion 13d, and at least one of the pair of second side wall portions 13c2 may form a first wall portion 13d. Alternatively, at least one of the pair of first side wall portions 13c1 may form a first wall portion 13d, and at least one of the pair of second side wall portions 13c2 may form a first wall portion 13d.

[0026] In this embodiment, as an example of an energy storage element unit 10 in which a plurality of wall portions 13 include a first wall portion 13d and a second wall portion 13e, an energy storage element unit 10 in which each of a pair of first side wall portions 13c1 forms a first wall portion 13d and each of a pair of second side wall portions 13c2 forms a second wall portion 13e will be described.

[0027] In the example shown in Figure 2, each of the multiple wall sections 13 is an independent member that is generally plate-shaped as a whole. Each of the multiple wall sections 13 is connected at its edge to the edge of an adjacent wall section 13, either directly or via a frame section 12, which will be described later. The connection of the edges of the multiple wall sections 13 forms a storage box 11 having a storage space for housing multiple energy storage element modules 20.

[0028] The structure of the wall portion 13 will now be described. First, as an example of the structure of the wall portion 13, the structure of the side wall portion 13c will be described. The description of the structure of the side wall portion 13c can also be applied to the bottom wall portion 13a and the top wall portion 13b, insofar as it does not contradict the description. Figure 3 is a perspective view of one of the side wall portions 13c as seen from inside the storage box 11. Figure 3 shows the first side wall portion 13c1 of a pair of first side wall portions 13c1, which is located on the opposite side of one side SB1 in the second direction DB, as seen from inside the storage box 11 (on the opposite side of one side SB1 in the second direction DB). Figure 4 is a perspective view of the top wall portion 13b as seen from inside the storage box 11 (on one side SA1 in the first direction DA). Figure 5 shows the wall portion 13 of the storage box 11, excluding the upper wall portion 13b and one of the first side wall portions 13c1 (the first side wall portion 13c1 located on the opposite side SB1 in the second direction DB), and the frame portion 12 connecting the wall portions 13. Note that in Figure 5, the resin plate 91 for the side wall portion 13c is not shown.

[0029] At least one of the multiple wall sections 13 is made of a laminate 90 including a resin plate 91 and a metal plate 92. As long as at least one of the multiple wall sections 13 is made of a laminate 90 including a resin plate 91 and a metal plate 92, the structure of the other wall sections 13 is not particularly limited. Each of the other wall sections 13 may be made of a single layer or laminate made of either the resin plate 91 or the metal plate 92, as described later, or it may be made of a laminate made of the resin plate 91 and the metal plate 92. That is, each of the other wall sections 13 may be a single layer made of the resin plate 91, a single layer made of the metal plate 92, or a laminate made of the resin plate 91 and the metal plate 92. From the viewpoint of ensuring the strength of the storage box 11, it is preferable that each of the multiple wall sections 13 includes a metal plate 92.

[0030] In this embodiment, at least a plurality of side wall portions 13c among the plurality of wall portions 13 are made of a laminate 90. That is, all of the plurality of side wall portions 13c included in the plurality of wall portions 13 are made of a laminate 90 including a resin plate 91 and a metal plate 92. In this embodiment, the top wall portion 13b and the four side wall portions 13c are laminates 90 made of resin plates 91 and metal plates 92. In this embodiment, the bottom wall portion 13a is a laminate made of two metal plates 92. The description of the resin plate 91 that constitutes the laminate 90 including the resin plate 91 and the metal plate 92 in this specification also applies to the resin plate 91 in a single layer or laminate that includes the resin plate 91 but does not include the metal plate 92, unless it is inconsistent. Similarly, the description of the metal plate 92 that constitutes the laminate 90 including the resin plate 91 and the metal plate 92 in this specification also applies to the metal plate 92 in a single layer or laminate that includes the metal plate 92 but does not include the resin plate 91, unless it is inconsistent.

[0031] The structure of the wall portion 13, which is a laminate 90 composed of a resin plate 91 and a metal plate 92, will be described in more detail using the first side wall portion 13c1 shown in Figure 3 as an example. In the example shown in Figure 3, the side wall portion 13c is a laminate 90 composed of a resin plate 91 and a metal plate 92 located inside the storage box 11, relative to the resin plate 91.

[0032] Figure 6 is a perspective view showing the resin plate 91 included in the side wall portion 13c shown in Figure 3. In the example shown in Figure 6, the resin plate 91 included in the side wall portion 13c has a substantially plate-like shape.

[0033] As described above, in this embodiment, each of the pair of first side wall portions 13c1 forms a first wall portion 13d, and each of the pair of second side wall portions 13c2 forms a second wall portion 13e. In particular, each of the pair of first side wall portions 13c1 forms a first wall portion 13d including a first resin plate 911, and each of the pair of second side wall portions 13c2 forms a second wall portion 13e including a second resin plate 912.

[0034] The first wall portion 13d includes a first resin plate 911, which is a resin plate 911 and has a resin plate body portion 911a and a connecting portion 911b extending from the edge of the resin plate body portion 911a in a direction intersecting the resin plate body portion 911a. In the example shown in Figures 3 and 6, the first wall portion 13d has a first metal plate 921 as a metal plate 92. The first wall portion 13d is also composed of a first laminate 901, which is a laminate 90. In the example shown in Figures 3 and 6, the first wall portion 13d is composed of a first laminate 901 which includes a first resin plate 911 and a first metal plate 921 that overlaps the resin plate body portion 911a.

[0035] The second wall portion 13e includes a second resin plate 912 as a resin plate 91, which is non-parallel to the resin plate body portion 911a of the first wall portion 13d. In this embodiment, the second resin plate 912 is perpendicular to the resin plate body portion 911a. In this embodiment, the second resin plate 912 is parallel to the connecting portion 911b. In this embodiment, the second resin plate 912 is a substantially rectangular, substantially plate-shaped member parallel to the first direction DA and the second direction DB. In this embodiment, the second wall portion 13e has a second metal plate 922 as a metal plate 92. The second wall portion 13e is also composed of a second laminate 902, which is a laminate 90. In this embodiment, the second wall portion 13e is composed of a second laminate 902, which includes the second resin plate 912 and the second metal plate 922 that overlaps the second resin plate 912.

[0036] In the example shown in Figure 6, the resin plate 91 included in the side wall portion 13c is provided with screw holes 95, which will be described later, used for fixing the resin plate 91 to the metal plate 92. The screw holes 95 are provided in the resin plate body portion 911a of the first resin plate 911. In the example shown in Figure 6, the resin plate 91 has a projection 95a on the surface facing the inside of the storage box 11 that extends toward the inside of the storage box 11. The screw holes 95 are provided in the projection 95a. The screw holes 95 do not penetrate the resin plate 91.

[0037] The resin plate 91 may be provided with ribs 93 that protrude from the resin plate 91, as shown in the resin plate 91 of the side wall portion 13c in Figure 6. The ribs 93 are provided on at least one of the resin plates 91 of the multiple wall portions 13 of the storage box 11, for example. The ribs 93 are provided on the resin plate 91 so as to protrude inward or outward from the storage box 11. In the example shown in Figure 6, the ribs 93 are provided so as to protrude inward from the storage box 11. As an example, all of the resin plates 91 included in the multiple wall portions 13 of the storage box 11 are provided with inwardly facing ribs 93.

[0038] In the example shown in Figure 6, the rib 93 has a lattice-like shape with a portion extending in the first direction DA and a portion extending in a direction perpendicular to the first direction DA. As another example, the rib 93 is made of a resin material integrally provided with the resin plate 91.

[0039] By providing ribs 93 on the resin plate 91, the strength of the resin plate 91 can be improved, thereby improving the strength of the storage box 11 and, furthermore, the energy storage element unit 10.

[0040] Next, the metal plate 92 will be described. The metal plate 92 has a flat main body portion 92a. The metal plate 92 may have a portion that connects the main body portion 92a to the resin plate 91, along with the main body portion 92a. Alternatively, the metal plate 92 may not have a portion that connects the main body portion 92a to the resin plate 91, and the main body portion 92a may be directly connected to the resin plate 91. In this embodiment, the metal plate 92 included in the side wall portion 13c does not have a portion that connects the main body portion 92a to the resin plate 91. In the laminate 90 that constitutes the side wall portion 13c, the main body portion 92a of the metal plate 92 is connected to the resin plate 91. As an example, in this embodiment, the main body portion 92a of the metal plate 92 included in the side wall portion 13c is in contact with the rib 93 of the resin plate 91. Also, in the example shown in Figure 3, the metal plate 92 included in the side wall portion 13c is provided with a through hole 94, which will be described later, used for fixing the resin plate 91 and the metal plate 92. The through hole 94 is provided in the main body portion 92a of the metal plate 92.

[0041] Figure 7 shows a part of the cross-section of the wall portion 13 along line AA in Figure 3. As shown in Figures 3 and 7, the resin plate 91 and the metal plate 92 included in the laminate 90 are fixed to each other using screws 96. The screw 96 has a head 96b and a shaft portion 96a extending from the head 96b. In this case, the resin plate 91 is provided with either a plurality of through holes 94 through which the shaft portion 96a of the screw 96 passes, or a plurality of screw holes 95 through which the shaft portion 96a passed through the plurality of through holes 94 is screwed. The other of the plurality of through holes 94 or plurality of screw holes 95 is provided in the metal plate 92. That is, the metal plate 92 is provided with the other of the plurality of through holes 94 or plurality of screw holes 95, which is different from the one provided in the resin plate 91.

[0042] In the wall portion 13 shown in Figures 3 and 6, the resin plate 91 is provided with a plurality of screw holes 95, and the metal plate 92 is provided with a plurality of through holes 94. In particular, in the first side wall portion 13c1 which forms the first wall portion 13d shown in Figures 3 and 6, as described above, the resin plate body portion 911a of the first resin plate 911 is provided with screw holes 95. Also, in the second side wall portion 13c2 which forms the second wall portion 13e in this embodiment, the second resin plate 912 is provided with screw holes 95. Furthermore, in both the first side wall portion 13c1 which is the first wall portion 13d, and the second side wall portion 13c2 which is the second wall portion 13e, the body portion 92a of the metal plate 92 is provided with through holes 94.

[0043] The resin plate 91 and the metal plate 92 can be fixed to each other by overlapping the through-hole 94 and the screw hole 95, and by screwing the shaft portion 96a of the screw 96 through the through-hole 94 into the screw hole 95. The number of through-holes 94 and screw holes 95 is not particularly limited as long as the resin plate 91 and the metal plate 92 can be fixed to each other. As an example, the number of through-holes 94 provided in the resin plate 91 or metal plate 92 of one wall section 13 is 9 to 12. Also, the number of screw holes 95 provided in the resin plate 91 or metal plate 92 of one wall section 13 is 9 to 12. In Figures 3 and 6, the resin plate 91 is provided with 9 screw holes 95. Also, in Figures 3 and 6, the metal plate 92 is provided with 9 screw holes 95.

[0044] Figure 8 is a side view showing the resin plate 91 and metal plate 92 included in the laminate 90 that constitutes the first side wall portion 13c1 shown in Figure 3, as viewed from the inside of the storage box 11 (opposite side SB1 in the second direction DB). The dimensional ratio of the size of the through hole 94 and the size of the metal plate 92 in Figure 8 has been changed from the actual dimensional ratio for the sake of illustration and ease of understanding. In Figure 8, holes and protrusions other than the through hole 94 provided in the resin plate 91 and metal plate 92, which are shown in Figures 3 and 6, have been omitted from the illustration.

[0045] In the example shown in Figure 8, the multiple through holes 94 include one reference through hole 94a and multiple wide through holes 94b. In Figure 8, the reference through hole 94a has a circular cross-section. Each of the multiple wide through holes 94b has a width greater than the diameter d1 of the reference through hole 94a in the direction in which each wide through hole 94b is aligned with the reference through hole 94a. For example, the wide through hole 94b labeled A1 in Figure 8 and the reference through hole 94a are aligned in the first direction DA. The width d2 of the wide through hole 94b labeled A1 in the second direction DB, where the wide through hole 94b and the reference through hole 94a are aligned, is greater than the diameter d1 of the reference through hole 94a. Furthermore, the wide through-hole 94b, denoted by the symbol A2 in Figure 8, and the reference through-hole 94a are aligned in direction DD, which is non-parallel to all of the first direction DA, the second direction DB, and the third direction DC. The width d3 of the wide through-hole 94b, denoted by the symbol A2, in direction DD where the wide through-hole 94b and the reference through-hole 94a are aligned is greater than the diameter d1 of the reference through-hole 94a. Although not shown in the figures, if the cross-section of the reference through-hole 94a is not circular, the diameter d1 of the reference through-hole 94a may be defined as the maximum width of the reference through-hole 94a.

[0046] In this embodiment, the reference through-hole 94a fixes the position of the shaft portion 96a that passes through the reference through-hole 94a. The reference through-hole 94a fixes the relative position of the shaft portion 96a that passes through the reference through-hole 94a with respect to the reference through-hole 94a. For example, the diameter d1 of the reference through-hole 94a is equal to the maximum width of the shaft portion 96a in a direction perpendicular to the axial direction of the screw 96. In this case, when the shaft portion 96a passes through the reference through-hole 94a, the shaft portion 96a comes into contact with the metal plate 92 within the reference through-hole 94a, thereby fixing the relative position of the shaft portion 96a with respect to the reference through-hole 94a. Although not shown in the figures, the reference through-hole 94a may have a portion through which the shaft portion 96a of the screw 96 passes, as well as a portion that engages with at least a part of the head 96b of the screw 96. In this case, the relative position of the shaft portion 96a with respect to the reference through hole 94a can be fixed by the engagement of a portion of the reference through hole 94a with at least a portion of the head 96b of the screw 96.

[0047] As an example, a wall portion 13 made of a laminate 90 has a pair of first sides 13f extending in a first stretching direction and a pair of second sides 13g extending in a second stretching direction perpendicular to the first stretching direction. In the example shown in Figure 8, the first side wall portion 13c1, which is a wall portion 13 made of a laminate 90, has a pair of first sides 13f extending in a third direction DC as the first stretching direction and a pair of second sides 13g extending in a first direction DA as the second stretching direction.

[0048] Here, the multiple wide through-holes 94b include a first wide through-hole 94c, a second wide through-hole 94d, and a third wide through-hole 94e. The first wide through-hole 94c and the reference through-hole 94a are aligned in the first extension direction. The second wide through-hole 94d and the reference through-hole 94a are aligned in the second extension direction. The third wide through-hole 94e and the reference through-hole 94a are located in different positions in the first and second extension directions. In other words, the third wide through-hole 94e does not correspond to either the first wide through-hole 94c or the second wide through-hole 94d. In the example shown in Figure 8, two first wide through-holes 94c are provided, aligned in the third direction DC together with the reference through-hole 94a. Also, two second wide through-holes 94d are provided, aligned in the first direction DA together with the reference through-hole 94a. Furthermore, four third wide through-holes 94e are provided, which are located in different positions in the third direction DC and the first direction DA compared to the standard through-hole 94a.

[0049] The first wide through-hole 94c has a width greater than the diameter d1 of the reference through-hole 94a in the first extension direction. In other words, the width d4 of the first wide through-hole 94c in the first extension direction shown in Figure 8 is greater than the diameter d1 of the reference through-hole 94a. In Figure 8, the width d4 of the first wide through-hole 94c in the first extension direction is greater than the width of the first wide through-hole 94c in the second extension direction. In Figure 8, the first wide through-hole 94c has the shape of a rounded rectangle extending in the first extension direction.

[0050] The second wide through-hole 94d has a width greater than the diameter d1 of the reference through-hole 94a in the second extension direction. In other words, the width d5 ​​of the second wide through-hole 94d in the second extension direction shown in Figure 8 is greater than the diameter d1 of the reference through-hole 94a. In Figure 8, the width d5 ​​of the second wide through-hole 94d in the second extension direction is greater than the width of the second wide through-hole 94d in the second extension direction. In Figure 8, the second wide through-hole 94d has the shape of a rounded rectangle extending in the second extension direction.

[0051] The third wide through-hole 94e has a larger diameter than the diameter d1 of the reference through-hole 94a. In other words, the diameter d6 of the third wide through-hole 94e shown in Figure 8 is larger than the diameter d1 of the reference through-hole 94a. In Figure 8, the third wide through-hole 94e has a circular cross-section. Although not shown, if the cross-section of the third wide through-hole 94e is not circular, the diameter d6 of the third wide through-hole 94e may be defined as the maximum width of the third wide through-hole 94e.

[0052] In this embodiment, in the side wall portion 13c, the reference through hole 94a is located closer to the upper wall portion 13b than to the bottom wall portion 13a. In the example shown in Figure 8, the reference through hole 94a provided in the main body portion 92a of the metal plate 92 of the first side wall portion 13c1 is located closer to the long side 131 of the upper wall portion 13b than to the long side 131 of the bottom wall portion 13a. Also, although not shown, the reference through hole 94a provided in the main body portion 92a of the metal plate 92 of the second side wall portion 13c2 is located closer to the short side 132 of the upper wall portion 13b than to the short side 132 of the bottom wall portion 13a.

[0053] The effects of the features of the through-holes 94 described above in this embodiment will now be explained. As described above, in this embodiment, at least one of the multiple wall portions 13 is composed of a laminate 90 including a resin plate 91 and a metal plate 92. The resin plate 91 is provided with either multiple through-holes 94 through which the shaft portion 96a of a screw 96 passes, or multiple screw holes 95 through which the shaft portion 96a passed through the multiple through-holes 94 is screwed in. The metal plate 92 is provided with the other of multiple through-holes 94 or multiple screw holes 95. By overlapping the through-holes 94 and screw holes 95, and screwing the shaft portion 96a of the screw 96 through the through-holes 94 into the screw holes 95, the resin plate 91 and the metal plate 92 can be fixed to each other to form the laminate 90.

[0054] In general, the resin constituting the resin plate 91 and the metal constituting the metal plate 92 have different coefficients of thermal expansion. In particular, the resin constituting the resin plate 91 has a higher coefficient of thermal expansion than the metal constituting the metal plate 92. Therefore, when the wall portion 13 is heated by the heat generated by the energy storage element module 20 housed inside the storage box, the resin plate 91 is expected to expand by a larger amount than the amount of thermal expansion of the metal plate 92.

[0055] Here, let's consider the case where, when the resin plate 91 and the metal plate 92 are fixed together using screws 96, there is no room for the shaft portion 96a, which is passed through each of the through holes 94, to shift within the through holes 94, and the relative position of each shaft portion 96a with respect to each of the through holes 94 is fixed. In this case, when the wall portion 13 is heated and the resin plate 91 expands due to heat, distortion may occur in the thermally expanded resin plate 91 because the relative position of each shaft portion 96a with respect to each of the through holes 94 is fixed.

[0056] In contrast, in this embodiment, the multiple through holes 94 include one reference through hole 94a and multiple wide through holes 94b. Each of the multiple wide through holes 94b has a width greater than the diameter d1 of the reference through hole 94a in the direction in which each wide through hole 94b and the reference through hole 94a are aligned. In this case, the shaft portion 96a passed through each of the wide through holes 94b is allowed to shift within the wide through hole 94b through which the shaft portion 96a passes in the direction in which the wide through hole 94b and the reference through hole 94a are aligned. Therefore, when the resin plate 91 expands due to thermal expansion in the direction of the multiple radial arrows labeled A3 in Figure 8, with the reference through hole 94a as the center, the shaft portion 96a is allowed to shift within the wide through holes 94b in accordance with the thermal expansion. This makes it possible to suppress distortion in the thermally expanded resin plate 91. This effectively suppresses plastic deformation and cracking in the thermally expanded resin plate 91.

[0057] Furthermore, in this embodiment, the reference through-hole 94a fixes the position of the shaft portion 96a that passes through the reference through-hole 94a. This makes it possible to determine the position at which the resin plate 91 begins to expand due to thermal expansion (the position where multiple arrows, when extended, intersect when multiple arrows labeled A3 in Figure 8 are extended) at the position of the reference through-hole 94a.

[0058] Furthermore, in this embodiment, the plurality of wide through holes 94b include a first wide through hole 94c, a second wide through hole 94d, and a third wide through hole 94e. The first wide through hole 94c and the reference through hole 94a are aligned in the first extending direction of the pair of first sides 13f. The second wide through hole 94d and the reference through hole 94a are aligned in the second extending direction of the pair of second sides 13g. The third wide through hole 94e and the reference through hole 94a are located in different positions in the first and second extending directions. The first wide through hole 94c has a width greater than the diameter d1 of the reference through hole 94a in the first extending direction. The second wide through hole 94d has a width greater than the diameter d1 of the reference through hole 94a in the second extending direction. The third wide through hole 94e has a diameter greater than the diameter d1 of the reference through hole 94a. By designing multiple wide through-holes 94b in this way, the shape of the multiple wide through-holes 94b can be made easily formed by processing the resin plate 91 or metal plate 92. For example, as shown in Figure 8, a metal plate 92 can be manufactured by forming a first wide through-hole 94c extending in the direction of extension of the first side 13f (first extension direction), a second wide through-hole 94d extending in the direction of extension of the second side 13g (second extension direction), and a third wide through-hole 94e having a circular cross-section. These wide through-holes 94b shown in Figure 8 are easier to form by processing the resin plate 91 or metal plate 92 compared to through-holes 94 that extend in directions different from the direction of extension of the first side 13f (first extension direction) and the direction of extension of the second side 13g (second extension direction).

[0059] In particular, in this embodiment, the width d4 of the first wide through-hole 94c in the first extending direction is greater than the width of the first wide through-hole 94c in the second extending direction. As a result, the shaft portion 96a passed through the first wide through-hole 94c is more likely to shift in the first extending direction than in the second extending direction within the first wide through-hole 94c. Also, the width d5 ​​of the second wide through-hole 94d in the second extending direction is greater than the width of the second wide through-hole 94d in the second extending direction. As a result, the shaft portion 96a passed through the second wide through-hole 94d is more likely to shift in the second extending direction than in the first extending direction within the second wide through-hole 94d. As described above, the first wide through-hole 94c and the second wide through-hole 94d in this embodiment guide the direction in which the shaft portion 96a passed through the first wide through-hole 94c shifts in the first extension direction, and the direction in which the shaft portion 96a passed through the second wide through-hole 94d shifts in the second extension direction, thereby guiding the direction in which the resin plate 91 expands due to thermal expansion. As a result, when the resin plate 91 expands due to thermal expansion, the resin plate 91 expands uniformly, and distortion of the resin plate 91 can be suppressed.

[0060] Furthermore, in this embodiment, at least several of the side wall portions 13c among the multiple wall portions 13 are made of a laminate 90. This makes it possible to make the multiple side wall portions 13c from a laminate 90 including a resin plate 91 and a metal plate 92, while suppressing distortion of the resin plate 91 in the side wall portions 13c.

[0061] Furthermore, in the side wall portion 13c of this embodiment, the reference through-hole 94a is located closer to the upper wall portion 13b than to the bottom wall portion 13a. This feature provides the following effects. As described above, each of the multiple wide through-holes 94b has a width greater than the diameter d1 of the reference through-hole 94a in the direction in which each wide through-hole 94b and the reference through-hole 94a are aligned. Therefore, the shaft portion 96a passed through the reference through-hole 94a has less room for misalignment than the shaft portion 96a passed through the wide through-hole 94b. In particular, in the wall portion 13 shown in Figure 8, the shaft portion 96a passed through the reference through-hole 94a has less room for misalignment in the vertical direction than the second wide through-hole 94d and the third wide through-hole 94e, whose width in the vertical direction (first direction DA) is greater than the diameter d1 of the reference through-hole 94a. As a result, the resin plate 91 is supported by the metal plate 92 at the position of the reference through-hole 94a, via the shaft portion 96a that passes through the reference through-hole 94a. By positioning the reference through-hole 94a closer to the upper wall portion 13b than to the bottom wall portion 13a, the position in which the resin plate 91 is supported by the metal plate 92 can be made closer to the upper wall portion 13b than to the bottom wall portion 13a. This allows the resin plate 91 to be supported by the metal plate 92 more stably by the action of gravity than when the resin plate 91 is supported by the metal plate 92 at a position closer to the bottom wall portion 13a than to the upper wall portion 13b.

[0062] Furthermore, in the wall portion 13 shown in Figures 3 and 6, the resin plate 91 is provided with a plurality of screw holes 95, and the metal plate 92 is provided with a plurality of through holes 94. This feature provides the following effects. In the wall portion 13 of this embodiment, which is composed of a laminate 90 including the resin plate 91 and the metal plate 92, the resin plate 91 covers the metal plate 92 from the outside of the storage box 11. Here, by providing a plurality of screw holes 95 in the resin plate 91 and a plurality of through holes 94 in the metal plate 92, the side of the wall portion 13 where the heads 96b of the screws 96 are exposed can be made to be on the inside of the storage box 11. This prevents the heads 96b of the screws 96 from being exposed to the outside of the storage box 11, and improves the aesthetic appearance of the energy storage element unit 10.

[0063] Next, a description will be given of how multiple wall sections 13 are connected to each other. In this embodiment, adjacent wall sections 12 are connected to each other via a frame section 12, which will be described later. As an example of how multiple wall sections 13 are connected to each other, a description will be given of how a first side wall section 13c1 forming a first wall section 13d and a second side wall section 13c2 forming a second wall section 13e are connected.

[0064] In this embodiment, the second wall portion 13e is connected to the first wall portion 13d by fixing the positional relationship between the first metal plate 921 of the first wall portion 13d and the second metal plate 922 of the second wall portion 13e. In this embodiment, the first metal plate 921 and the second metal plate 922 are both fixed to the frame portion 12, thereby fixing the positional relationship between the first metal plate 921 and the second metal plate 922, and the first wall portion 13d and the second wall portion 13e are connected to each other via the frame portion 12.

[0065] The first metal plate 921 and the second metal plate 922 may be fixed to the frame portion 12 by being directly connected to the frame portion 12, or they may be fixed to the frame portion 12 by being connected to the frame portion 12 via a connecting member (not shown). In the example shown in Figure 3, the first metal plate 921 is provided with a connecting through-hole 92h. In this case, the first metal plate 921 can be fixed to the frame portion 12 by fixing a screw or rivet through the connecting through-hole 92h to the connecting member, and then fixing the connecting member to the frame portion 12. Although not shown, the second metal plate 922 may also be provided with a connecting through-hole 92h, similar to the first metal plate 921. In this case, the second metal plate 922 can be fixed to the frame portion 12 in the same way as the first metal plate 921 by fixing a screw or rivet through the connecting through-hole 92h to the connecting member, and then fixing the connecting member to the frame portion 12.

[0066] As shown in Figures 3 and 6, the resin plates 91, such as the first resin plate 911 and the second resin plate 912, may have insertion projections 91c in positions that do not overlap with the metal plate 92. Also, as shown in Figure 5, the frame portion 12 may have frame through holes 12c. In this case, when the metal plates 92, such as the first metal plate 921 and the second metal plate 922, are fixed to the frame portion 12, the wall portions 13, such as the first wall portion 13d and the second wall portion 13e, can be more stably supported by the frame portion 12 by inserting the insertion projections 91c into the frame through holes 12c.

[0067] By fixing the positional relationship between the first metal plate 921 and the second metal plate 922, the positional relationship between the first resin plate 911, which together with the first metal plate 921 constitutes the first laminate 901, and the second resin plate 912, which together with the second metal plate 922 constitutes the second laminate 902, is also fixed.

[0068] Figure 9 shows a portion of the area around the edge of the first resin plate 911 and the edge of the second resin plate 912 in the cross-sections of the first wall portion 13d and the second wall portion 13e along line BB in Figure 1. In particular, Figure 9 shows a portion of the area around the edge of the first side wall portion 13c1 of the pair of first side wall portions 13c1 that make up the first wall portion 13d, which is located on the opposite side SB1 in the second direction DB, and the edge of the second side wall portion 13c2 of the pair of second side wall portions 13c2 that make up the second wall portion 13e, which is located on the opposite side SB1 in the third direction DC.

[0069] As shown in Figures 3, 6, and 9 and described above, the first resin plate 911 has a resin plate body portion 911a and a connecting portion 911b that extends from the edge of the resin plate body portion 911a in a direction intersecting the resin plate body portion 911a. In the examples shown in Figures 3, 6, and 9, the connecting portion 911b extends in a direction perpendicular to the resin plate body portion 911a (second direction DB). In the examples shown in Figures 3 and 6, the resin plate body portion 911a is a roughly rectangular, roughly plate-like portion parallel to the first direction DA and the third direction DC. The connecting portion 911b is in a direction parallel to the first direction DA and the second direction DB.

[0070] In the example shown in Figure 9, the edge of the connecting portion 911b and the edge of the second resin plate 912 face each other in a direction perpendicular to the resin plate body portion 911a (second direction DB). Here, the edge of the connecting portion 911b and the edge of the second resin plate 912 are not directly joined to each other. In the example shown in Figure 9, the positional relationship between the first metal plate 921 and the second metal plate 922 is fixed, which in turn fixes the positional relationship between the first resin plate 911 and the second resin plate 912, thereby maintaining the positional relationship between the edge of the connecting portion 911b and the edge of the second resin plate 912. Because the edge of the connecting portion 911b and the edge of the second resin plate 912 are not directly joined to each other, when the edge of the connecting portion 911b and the edge of the second resin plate 912 are in contact, it is permissible for them to be misaligned relative to each other. Therefore, when the resin plate 91 expands due to heat and the edge of the connecting portion 911b comes into contact with the edge of the second resin plate 912, a gap is created between the edges, reducing the force with which the edges of the connecting portion 911b and the second resin plate 912 press against each other. This prevents the resin plate 91 from becoming distorted due to the force with which the edges of the connecting portion 911b and the second resin plate 912 press against each other when the wall portion 13 is heated and the resin plate 91 expands due to heat.

[0071] In the example shown in Figure 9, the second resin plate 912 is spaced apart from the first resin plate 911 in a direction perpendicular to the resin plate body 911a (second direction DB). Therefore, when the resin plate 91 undergoes thermal expansion, contact between the edge of the connecting portion 911b and the edge of the second resin plate 912 can be suppressed. Furthermore, even if the edge of the connecting portion 911b and the edge of the second resin plate 912 do come into contact, the force with which the edges of the connecting portion 911b and the edge of the second resin plate 912 push against each other can be more effectively reduced. As a result, distortion of the resin plate 91 due to the pushing of the edges of the connecting portion 911b and the edge of the second resin plate 912 against each other during thermal expansion can be effectively suppressed.

[0072] In particular, in this embodiment, the resin plate 91 is allowed to expand due to thermal expansion due to the action of the standard through-hole 94a and the wide through-hole 94b described above. In this case, contact between the edge of the connecting portion 911b that has expanded due to thermal expansion and the edge of the second resin plate 912 can be suppressed. Furthermore, even if the edge of the connecting portion 911b that has expanded due to thermal expansion and the edge of the second resin plate 912 do come into contact, the force with which the edges of the connecting portion 911b and the edge of the second resin plate 912 push against each other can be reduced.

[0073] Here, at least a portion of the connecting portion 911b overlaps a portion of the second resin plate 912 in the thickness direction of the second resin plate 912. In the example shown in Figure 9, a portion of the connecting portion 911b overlaps a portion of the second resin plate 912 in the third direction DC, which is the thickness direction of the second resin plate 912. In the example shown in Figure 3, the connecting portion 911b extends in the direction in which the edge of the resin plate body portion 911a on which the connecting portion 911b is provided extends (first direction DA). The connecting portion 911b extends over the entire range in which the edge of the resin plate body portion 911a on which the connecting portion 911b is provided extends. The edge of the second resin plate 912 on which the connecting portion 911b overlaps extends in the direction in which the connecting portion 911b extends (first direction DA). Furthermore, a portion of the connecting portion 911b overlaps with the edge of the second resin plate 912 over the entire extent of the edge of the second resin plate 912 that the connecting portion 911b overlaps with.

[0074] In the example shown in Figure 9, the connecting portion 911b has a thin plate connecting portion 911c at its edge having a thickness t2 smaller than the thickness t1 of the resin plate body portion 911a. The second resin plate 912 also has a thin plate portion 912a at its edge having a thickness t4 smaller than the maximum thickness t3 of the second resin plate 912. At least a portion of the thin plate connecting portion 911c overlaps at least a portion of the thin plate portion 912a in the thickness direction (third direction DC) of the second resin plate 912. Furthermore, in a direction perpendicular to the thickness direction of the second resin plate 912, the thin plate connecting portion 911c faces a portion of the second resin plate 912, and the thin plate portion 912a faces a portion of the connecting portion 911b. In the example shown in Figure 9, in the thickness direction (second direction DB) of the resin plate body portion 911a, the thin plate connecting portion 911c faces a part of the second resin plate 912, and the thin plate portion 912a faces a part of the connecting portion 911b.

[0075] In the example shown in Figure 9, the thin plate connecting portion 911c extends in the direction in which the connecting portion 911b extends (first direction DA) and covers the entire range over which the connecting portion 911b extends. Similarly, the thin plate portion 912a extends in the direction in which the edge of the second resin plate 912 on which the thin plate portion 912a is provided extends (first direction DA) and covers the entire range over which the edge extends. Furthermore, a portion of the thin plate connecting portion 911c overlaps with the thin plate portion 912a over the entire range over which the thin plate portion 912a extends.

[0076] At least a portion of the connecting portion 911b may overlap a portion of the second resin plate 912 from the outside of the storage box 11, or it may overlap a portion of the second resin plate 912 from the inside of the storage box 11. In the example shown in Figure 9, a portion of the connecting portion 911b overlaps a portion of the second resin plate 912 from the outside of the storage box 11. In the example shown in Figure 9, a portion of the thin plate connecting portion 911c overlaps a portion of the thin plate portion 912a from the outside of the storage box 11.

[0077] As described above, in this embodiment, each of the pair of first side wall portions 13c1 forms a first wall portion 13d including a first resin plate 911, and each of the pair of second side wall portions 13c2 forms a second wall portion 13e including a second resin plate 912. Figure 10 is a diagram showing cross-sections of the first resin plate 911 included in each of the pair of first side wall portions 13c1 and the second resin plate 912 included in each of the pair of second side wall portions 13c2 according to this embodiment, along the line BB in Figure 1. The dimensional ratios of the elements included in the first resin plate 911 and the second resin plate 912 in Figure 10 have been changed from the actual dimensional ratios for the convenience of illustration and ease of understanding. In Figure 10, elements other than the first resin plate 911 and the second resin plate 912, such as the metal plate 92 and the ribs 93 provided on the resin plate 91, are not shown.

[0078] In this embodiment, as shown in Figure 10, the first resin plates 911 of the pair of first side wall portions 13c1 have a pair of connecting portions 911b that extend from the edges on both sides of the resin plate body portion 911a in the direction in which the pair of long sides 131 of the bottom wall portion 13a extend (third direction DC). In addition, at least a portion of each of the pair of connecting portions 911b overlaps a portion of the second resin plate 912 from the outside of the storage box 11.

[0079] The effects of the features of the first resin plate 911 and the second resin plate 912 described above in this embodiment will now be explained. As described above, in order to suppress distortion of the resin plate 91 when the resin plate 91 expands due to heat, it is sometimes necessary to avoid directly joining the first resin plate 911 and the second resin plate 912. In particular, it is sometimes necessary to avoid directly joining the edge of the connecting portion 911b and the edge of the second resin plate 912 to each other. In particular, it is sometimes necessary to separate the second resin plate 912 from the first resin plate 911 in a direction perpendicular to the resin plate body portion 911a (second direction DB). Here, in this embodiment, at least a part of the connecting portion 911b overlaps a part of the second resin plate 912 in the thickness direction of the second resin plate 912. This prevents the interior of the storage box from being visible from between the edge of the connection part 911b and the edge of the second resin plate 912 when the user of the energy storage element unit 10 looks at the storage box 11 from the outside, in the portion where the connection part 911b overlaps with the second resin plate 912. This prevents the interior of the storage box from being visible from between the edge of the connection part 911b and the edge of the second resin plate 912, even when the first resin plate 911 and the second resin plate 912 are not directly joined, especially when the edge of the connection part 911b and the edge of the second resin plate 912 are not directly joined to each other. This improves the aesthetic appearance of the energy storage element unit 10. It also prevents foreign objects from entering the interior of the storage box 11 from between the edge of the connection part 911b and the edge of the second resin plate 912.

[0080] Furthermore, in this embodiment, at least a portion of the thin plate connecting portion 911c overlaps with at least a portion of the thin plate portion 912a in the thickness direction (third direction DC) of the second resin plate 912. Then, in a direction perpendicular to the thickness direction of the second resin plate 912, the thin plate connecting portion 911c faces a portion of the second resin plate 912, and the thin plate portion 912a faces a portion of the connecting portion 911b. This makes it possible to reduce the thickness t5 of the storage box 11 in the portion where the connecting portion 911b and the second resin plate 912 overlap, as shown in Figure 9, while overlapping at least a portion of the connecting portion 911b with a portion of the second resin plate 912. In particular, the thickness t5 of the storage box 11 in the portion where the connecting portion 911b and the second resin plate 912 overlap can be made less than or equal to the thickness t1 of the resin plate body portion 911a and less than or equal to the maximum thickness t3 of the second resin plate 912.

[0081] Furthermore, in this embodiment, at least a portion of the connecting portion 911b overlaps a portion of the second resin plate 912 from the outside of the storage box 11. The effects of this feature will be explained with reference to Figure 11. Figure 11 is a diagram illustrating the effects of the features of the first resin plate 911 and the second resin plate 912 in this embodiment.

[0082] Figure 11 is a cross-sectional view of the first resin plate 911 and the second resin plate 912, which have different configurations from the first resin plate 911 and the second resin plate 912 shown in Figure 10. The first resin plate 911 and the second resin plate 912 shown in Figure 11 differ from the first resin plate 911 and the second resin plate 912 shown in Figure 10 only in that a part of the connecting portion 911b overlaps a part of the second resin plate 912 from the inside of the storage box 11. The dimensional ratios of the elements included in the first resin plate 911 and the second resin plate 912 in Figure 11 have been changed from the actual dimensional ratios for the sake of illustration and ease of understanding. In Figure 11, elements other than the first resin plate 911 and the second resin plate 912, such as the metal plate 92 and the ribs 93 provided on the resin plate 91, are not shown. Furthermore, the energy storage element unit 10 having the first resin plate 911 and the second resin plate 912 shown in Figure 11 may also be included in the scope of the energy storage element unit 10 of the present invention.

[0083] In the example shown in Figure 11, consider the case where the resin plate body portion 911a expands due to thermal expansion. In this case, the dimension w5 of the resin plate body portion 911a in the thickness direction (third direction DC) of the second resin plate 912 increases, as shown in Figure 11. As a result, a part of the connecting portion 911b and a part of the second resin plate 912 come into contact in the thickness direction of the second resin plate 912 and can push against each other. Therefore, the resin plate 91 can be distorted by the force exerted between the edge of the connecting portion 911b and the edge of the second resin plate 912.

[0084] In contrast, in this embodiment, when the resin plate body portion 911a expands due to thermal expansion and the dimension w5 increases, the connecting portion 911b is considered to move away from the second resin plate 912 in the thickness direction of the second resin plate 912. This prevents a part of the connecting portion 911b and a part of the second resin plate 912 from contacting and pushing against each other in the thickness direction of the second resin plate 912. Therefore, it is possible to prevent the resin plate 91 from being distorted by the force of the edges of the connecting portion 911b and the edges of the second resin plate 912 pushing against each other.

[0085] Furthermore, in this embodiment, each of the pair of first side wall portions 13c1 forms a first wall portion 13d including a first resin plate 911, and each of the pair of second side wall portions 13c2 forms a second wall portion 13e including a second resin plate 912. The first resin plate 911 of the pair of first side wall portions 13c1 has a pair of connecting portions 911b that extend from the edges on both sides of the resin plate body portion 911a in the direction in which the pair of long sides 131 of the bottom wall portion 13a extend (third direction DC). At least a part of each of the pair of connecting portions 911b overlaps a part of the second resin plate 912 from the outside of the storage box 11. The effects of this feature will be explained with reference to Figure 12. Figure 12 is a diagram for explaining the effects of the features of the first resin plate 911 and the second resin plate 912 of this embodiment.

[0086] Figure 12 is a cross-sectional view of the first resin plate 911 and the second resin plate 912, which have different configurations from the first resin plate 911 and the second resin plate 912 shown in Figure 10. The first resin plate 911 and the second resin plate 912 shown in Figure 12 differ from the first resin plate 911 and the second resin plate 912 shown in Figure 10 only in that each of the pair of first side wall portions 13c1 forms a second wall portion 13e, and each of the pair of second side wall portions 13c2 forms a first wall portion 13d. The dimensional ratios of the elements included in the first resin plate 911 and the second resin plate 912 in Figure 12 have been changed from the actual dimensional ratios for the sake of illustration and ease of understanding. In Figure 12, elements other than the first resin plate 911 and the second resin plate 912, such as the metal plate 92 and the ribs 93 provided on the resin plate 91, are not shown. Furthermore, the energy storage element unit 10 having the first resin plate 911 and the second resin plate 912 shown in Figure 12 may also be included in the scope of the energy storage element unit 10 of the present invention.

[0087] In both Figure 10 and Figure 12, at least a portion of each of the pair of connecting portions 911b overlaps a portion of the second resin plate 912 from the outside of the storage box 11. In this case, the edge of the second resin plate 912 faces a portion of the first resin plate 911 in the thickness direction of the resin plate body portion 911a. Here, in the example shown in Figure 10, each of the pair of second side wall portions 13c2 connected to the short side 132 of the bottom wall portion 13a forms a second wall portion 13e that includes the second resin plate 912. On the other hand, in the example shown in Figure 12, each of the pair of first side wall portions 13c1 connected to the long side 131 of the bottom wall portion 13a forms a second wall portion 13e that includes the second resin plate 912. For this reason, in the example shown in Figure 10, the dimension w6 of the second resin plate 912 in the thickness direction of the resin plate body portion 911a is smaller than in the example shown in Figure 12. For this reason, the increase in the dimension w6 of the second resin plate 912 when it is heated and expands is smaller in the example shown in Figure 10 than in the example shown in Figure 12. Therefore, in the example shown in Figure 10, when the second resin plate 912 expands due to heat, it is easier to suppress the contact between the edge of the second resin plate 912 and the first resin plate 911 in the thickness direction of the resin plate body 911a, and the pushing force between the first resin plate 911 and the second resin plate 912. As a result, in the example shown in Figure 10, the deformation of the resin plate 91 due to the pushing force between the edge of the connecting portion 911b and the edge of the second resin plate 912 can be suppressed more effectively.

[0088] Next, the upper wall portion 13b in this embodiment will be described. In describing the upper wall portion 13b, explanations that are common to the side wall portion 13c described above will be omitted as appropriate. Figure 13 is a perspective view showing the resin plate 91 included in the upper wall portion 13b.

[0089] In the examples shown in Figures 4 and 13, the resin plate 91 included in the upper wall portion 13b does not have a portion corresponding to the connecting portion 911b that overlaps with a part of the resin plate 91 included in the wall portion 13 that connects to the upper wall portion 13b. Therefore, the upper wall portion 13b shown in Figure 4 does not constitute the first wall portion 13d. Also, the resin plate 91 included in the upper wall portion 13b does not have a portion that overlaps with the connecting portion 911b of the resin plate 91 included in the wall portion 13 that connects to the upper wall portion 13b. Therefore, the upper wall portion 13b shown in Figure 4 does not constitute the second wall portion 13e. Although not shown, the upper wall portion 13b may constitute either the first wall portion 13d or the second wall portion 13e. In this case, at least one of the multiple side wall portions 13c connected to the upper wall portion 13b constitutes either the first wall portion 13d or the second wall portion 13e.

[0090] Figure 14 is a perspective view showing a metal plate 92 included in the upper wall portion 13b. The metal plate 92 included in the upper wall portion 13b shown in Figure 14 may include a main body portion 92a and a connecting portion 92d which includes an upright portion 92e that rises from the main body portion 92a and a portion that connects to the resin plate 91. In the example shown in Figure 14, the metal plate 92 has a plurality of connecting portions 92d, each being a flat plate parallel to the first direction DA and the second direction DB, and including an upright portion 92e that extends in the second direction DB. The upright portions 92e of the plurality of connecting portions 92d face each other in the third direction DC. In the example shown in Figure 14, the metal plate 92 has two connecting portions 92d.

[0091] In the example shown in Figure 14, the connecting portion 92d is connected to the end of the upright portion 92e on the side where the main body portion 92a is located, and further has a flat plate-shaped first connecting portion 92f parallel to the main body portion 92a. The connecting portion 92d is then connected to the main body portion 92a at the first connecting portion 92f. The first connecting portion 92f of the connecting portion 92d and the main body portion 92a are connected, for example, by welding, riveting, or burring crimping. Also in the example shown in Figure 14, the connecting portion 92d is connected to the end of the upright portion 92e on the side opposite to where the main body portion 92a is located, and further has a flat plate-shaped second connecting portion 92g parallel to the resin plate main body portion 911a. The second connecting portion 92g of the connecting portion 92d is the part that connects to the resin plate 91 of the upper wall portion 13b shown in Figure 13.

[0092] The connecting portion 92d can be made of the same metal material as the metal material that constitutes the main body portion 92a. The connecting portion 92d may be formed, for example, by bending a flat metal material.

[0093] Furthermore, when the metal plate 92 is included in the laminate 90 that constitutes the upper wall portion 13b together with the resin plate 91, the metal plate 92 does not need to have a connecting portion 92d. In this case, the resin plate body portion 911a of the resin plate 91 and the body portion 92a of the metal plate 92 may be in contact with each other in the laminate 90 that constitutes the upper wall portion 13b.

[0094] In the upper wall portion 13b shown in Figures 4, 13, and 14, the resin plate 91 is provided with through holes 94 used for screw fastening to the metal plate 92. In the upper wall portion 13b shown in Figures 4, 13, and 14, the metal plate 92 is provided with screw holes 95 used for screw fastening to the resin plate 91. In particular, the second connecting portion 92g of the metal plate 92 is provided with screw holes 95 used for screw fastening to the resin plate 91.

[0095] In the upper wall portion 13b shown in Figures 4, 13, and 14, the resin plate 91 and the metal plate 92 can be fixed to each other by overlapping the through hole 94 and the screw hole 95, and screwing the shaft portion 96a of the screw 96 through the through hole 94 into the screw hole 95. In particular, since the resin plate 91 is provided with a through hole 94 and the metal plate 92 is provided with a screw hole 95, the shaft portion 96a of the screw 96 can be screwed through the through hole 94 into the screw hole 95 from the outside of the storage box 11 while the resin plate 91 is overlapping the metal plate 92 fixed to the frame portion 12.

[0096] The description of the multiple through holes 94 provided in the metal plate 92 of the side wall portion 13c shown in Figures 3 and 8 may also apply to the multiple through holes 94 provided in the resin plate 91 of the upper wall portion 13b shown in Figure 13, as long as it does not contradict the description. For example, the multiple through holes 94 provided in the resin plate 91 of the upper wall portion 13b shown in Figure 13 may include one standard through hole 94a and multiple wide through holes 94b. Also, the description of the multiple screw holes 95 provided in the resin plate 91 of the side wall portion 13c shown in Figure 6 may also apply to the multiple screw holes 95 provided in the metal plate 92 of the upper wall portion 13b shown in Figure 14, as long as it does not contradict the description.

[0097] Next, the bottom wall portion 13a will be described. In the example shown in Figure 5, the bottom wall portion 13a is a laminate composed of two metal plates 92. In the example shown in Figure 5, the bottom wall portion 13a includes an outer metal plate 923 and an inner metal plate 924 located inside the storage box 11 (on the opposite side of SA1 in the first direction DA) from the outer metal plate 923. In the example shown in Figure 5, the outer metal plate 923 has a flat outer metal plate body portion 923a and a bent portion 923b that is bent relative to the outer metal plate body portion 923a.

[0098] Although not shown in the figures, the bottom wall portion 13a may be composed of a laminate 90 including a resin plate 91 and a metal plate 92. In this case, the description of the structure of the side wall portion 13c, which is composed of a laminate 90 including a resin plate 91 and a metal plate 92, can also be applied to the bottom wall portion 13a, which is composed of a laminate 90 including a resin plate 91 and a metal plate 92, as long as it does not contradict the description.

[0099] Next, the frame portion 12 will be described. The frame portion 12 is a member that connects adjacent wall portions 13. In Figure 5, the frame portion 12 constitutes the sides of the storage box 11, which has a roughly rectangular parallelepiped shape. In the example shown in Figure 5, one of the multiple wall portions 13 has one edge, and the other wall portion 13 adjacent to the one wall portion 13 has another edge that is close to the said edge. The frame portion 12 has an L-shaped cross-section, and the said edge and the other edge are connected via the L-shaped frame portion 12. In the example shown in Figure 5, the frame portion 12 has a flat first portion 121 and a flat second portion 122 that is perpendicular to and connected to the first portion 121, thus forming an L-shaped cross-section. Then, one edge is connected to one of the first part 121 and the second part 122, and the other edge is connected to the other of the first part 121 and the second part 122, thereby connecting adjacent wall portions 13 to each other.

[0100] In this embodiment, as shown in Figure 5, the frame portion 12 connects the upper wall portion 13b to each of the four side wall portions 13c, and also connects adjacent side wall portions 13c to each other. In the example shown in Figure 5, the frame portion 12 has a rectangular frame-shaped first frame portion 12a extending between the upper wall portion 13b and the four side wall portions 13c, and four rod-shaped second frame portions 12b, each extending between adjacent side wall portions 13c. The first frame portion 12a and each of the four second frame portions 12b are fixed to each other at the corners of the upper wall portion 13b. In the example shown in Figure 5, the frame through-holes 12c described above are provided in both the first frame portion 12a and the second frame portions 12b.

[0101] In the example shown in Figure 5, no frame portion 12 is provided between the bottom wall portion 13a and each of the four side wall portions 13c. In the example shown in Figure 5, the outer metal plate 923 of the bottom wall portion 13a has a bent portion 923b, and the bottom wall portion 13a and each of the four side wall portions 13c are fixed to each other using the bent portion 923b. That is, each of the four side wall portions 13c is fixed to the bent portion 923b.

[0102] As shown in Figure 1, the energy storage element unit 10 may further include a decorative panel 19 provided in the storage box 11 and covering one of the multiple side wall portions 13c. The decorative panel 19 is a member that protects the one side wall portion 13c and the components provided on the one side wall portion 13c.

[0103] The decorative panel 19 has a plurality of decorative wall sections 19a, including at least a first decorative wall section 19b and a second decorative wall section 19c. The material of the plurality of decorative wall sections 19a is a resin material. The material of the plurality of decorative wall sections 19a may be the same resin material as the material of the resin plate 91 of the wall section 13. Any two decorative wall sections 19a included in the plurality of decorative wall sections 19a that are connected to each other without the interposition of other decorative wall sections 19a can be considered as the first decorative wall section 19b and the second decorative wall section 19c.

[0104] In the example shown in Figure 1, the decorative panel 19 has a plurality of decorative wall sections 19a, consisting of a main decorative wall section 19d and a plurality of connecting decorative wall sections 19e. The main decorative wall section 19d is a roughly plate-shaped decorative wall section 19a parallel to the side wall section 13c covered by the decorative panel 19. The connecting decorative wall sections 19e are roughly plate-shaped decorative wall sections 19a perpendicular to the main decorative wall section 19d, connecting the main decorative wall section 19d and the storage box 11. In the example shown in Figure 1, the decorative panel 19 has three connecting decorative wall sections 19e. One of the three connecting decorative wall sections 19e is located between the edge of one side SB1 in the second direction DB of the main decorative wall section 19d and the storage box 11. Another of the three connecting decorative wall sections 19e is located between the edge of the main decorative wall section 19d opposite to the one side SB1 in the second direction DB of the main decorative wall section 19d and the storage box 11. Another of the three connecting decorative wall sections 19e is located between the connecting decorative wall section 19e and the edge of the main decorative wall section 19d opposite to one side SA1 in the first direction DA, and the storage box 11. In this case, the main decorative wall section 19d and one of the three connecting decorative wall sections 19e may form the first decorative wall section 19b, and the other one may form the second decorative wall section 19c.

[0105] In this embodiment, as an example of a decorative panel 19 in which a plurality of decorative wall sections 19a include a first decorative wall section 19b and a second decorative wall section 19c, a decorative panel 19 in which a connecting decorative wall section 19e located between the edge of the main decorative wall section 19d on the opposite side SA1 in the first direction DA (upper side in Figure 1) and the storage box 11 forms the first decorative wall section 19b, and the main decorative wall section 19d forms the second decorative wall section 19c will be described.

[0106] Figure 15 shows a portion of the periphery of the edges of the first decorative wall section 19b and the second decorative wall section 19c, along the CC line in Figure 1. In the example shown in Figure 15, the first decorative wall section 19b is provided with decorative wall screw holes 19g. The decorative wall screw holes 19g are located away from the edge of the first decorative wall section 19b. In the example shown in Figure 15, the first decorative wall section 19b has a decorative wall projection 19f, and the decorative wall screw holes 19g are provided in the decorative wall projection 19f. Also in the example shown in Figure 15, the second decorative wall section 19c has a decorative wall connecting section 19i with a decorative wall through-hole 19h at its tip. In the example shown in Figure 15, the decorative wall connecting section 19i is a projection-like portion extending from a position away from the edge of the second decorative wall section 19c. In the example shown in Figure 15, the positional relationship between the first decorative wall section 19b and the second decorative wall section 19c is fixed by overlapping the decorative wall through-hole 19h and the decorative wall screw hole 19g, and by screwing the shaft of the screw 19j through the decorative wall through-hole 19h into the decorative wall screw hole 19g. Therefore, in the example shown in Figure 15, although the positional relationship between the first decorative wall section 19b and the second decorative wall section 19c is fixed, the edges of the first decorative wall section 19b and the edges of the second decorative wall section 19c are not directly joined to each other.

[0107] Because the edges of the first decorative wall section 19b and the second decorative wall section 19c are not directly joined to each other, when the decorative wall section 19a undergoes thermal expansion, a gap is created between the edges, reducing the force with which the edges of the first decorative wall section 19b and the second decorative wall section 19c press against each other. This suppresses distortion of the decorative wall section 19a. This effectively suppresses plastic deformation and cracking in the thermally expanded decorative wall section 19a.

[0108] In the example shown in Figure 15, the first decorative wall section 19b has a decorative wall section main body 19b1 and a decorative connecting section 19b2 extending from the edge of the decorative wall section main body 19b1 in a direction intersecting the decorative wall section main body 19b1. In the example shown in Figure 15, the decorative connecting section 19b2 extends in a direction perpendicular to the decorative wall section main body 19b1 (first direction DA). The second decorative wall section 19c is not parallel to the decorative wall section main body 19b1. In the example shown in Figure 15, the second decorative wall section 19c is perpendicular to the decorative wall section main body 19b1. In the example shown in Figure 15, the second decorative wall section 19c is parallel to the second decorative wall section 19c. At least a portion of the decorative connecting section 19b2 overlaps a portion of the second decorative wall section 19c in the thickness direction of the second decorative wall section 19c. In the example shown in Figure 15, a portion of the decorative connection portion 19b2 overlaps with a portion of the second decorative wall portion 19c in the thickness direction (third direction DC) of the second decorative wall portion 19c.

[0109] By having at least a portion of the decorative connection portion 19b2 overlap a portion of the second decorative wall portion 19c in the thickness direction of the second decorative wall portion 19c, the following effects can be obtained. As described above, in order to suppress distortion of the decorative wall portion 19a when the decorative wall portion 19a expands due to thermal expansion, it is sometimes necessary to avoid directly joining the edge of the first decorative wall portion 19b and the edge of the second decorative wall portion 19c. In this embodiment, at least a portion of the decorative connection portion 19b2 overlaps a portion of the second decorative wall portion 19c in the thickness direction of the second decorative wall portion 19c. As a result, when a user of the energy storage element unit 10 looks at the decorative panel 19 from the outside of the energy storage element unit 10, it is possible to suppress the visibility of the portion of the storage box 11 covered by the decorative panel 19 from between the edge of the first decorative wall portion 19b and the edge of the second decorative wall portion 19c in the portion where the decorative connection portion 19b2 overlaps the second decorative wall portion 19c. This prevents the portion of the storage box 11 covered by the decorative panel 19 from being visible from between the edges of the first decorative wall section 19b and the second decorative wall section 19c, even if the edges of the first decorative wall section 19b and the second decorative wall section 19c are not directly joined. This improves the aesthetic appearance of the energy storage element unit 10. It also prevents foreign objects from entering between the storage box 11 and the decorative panel 19 from between the edges of the first decorative wall section 19b and the second decorative wall section 19c.

[0110] The above-described explanation regarding the resin plate body portion 911a and the connecting portion 911b of the first resin plate 911 also applies to the decorative wall portion body portion 19b1 and the decorative connecting portion 19b2 of the first decorative wall portion 19b, unless otherwise contradictory. Furthermore, the above-described explanation regarding the portion of the second resin plate 912 that overlaps with at least a part of the connecting portion 911b also applies to the portion of the second decorative wall portion 19c that overlaps with at least a part of the decorative connecting portion 19b2, unless otherwise contradictory.

[0111] Next, the control module 14 will be described. The control module 14 has one or more functions, for example, a function to control the charging and discharging of the multiple energy storage element modules 20, a function to monitor the charging state (e.g., charge amount) of the energy storage element modules 20, and a function to monitor whether or not there is an abnormality in the energy storage element modules 20. The control module 14 may also transmit information such as the charging state and abnormality monitoring results of the energy storage element modules 20 to a control device installed outside the energy storage element unit 10. The control module 14 may also have a switch to switch between electrical connection and disconnection between the external wiring (e.g., building wiring) of the energy storage element unit 10 and the energy storage element modules 20.

[0112] Figure 16 shows multiple energy storage element modules 20 housed in a storage box 11. As shown in Figure 16, the energy storage element unit 10 has two energy storage element module combinations 15. Each energy storage element module combination 15 has multiple energy storage element modules 20 stacked in a first direction DA. The two energy storage element module combinations 15 are arranged side by side in a second direction DB that is not parallel to the first direction DA.

[0113] In the illustrated example, the first energy storage element module assembly 15A has three energy storage element modules 20 stacked in the first direction DA. The second energy storage element module assembly 15B is adjacent to the first energy storage element module assembly 15A from one side SB1 in the second direction DB. As shown in Figure 2, the second energy storage element module assembly 15B supports the control module 14 from one side SA1 in the first direction DA. Figure 17 shows one energy storage element module 20 included in the energy storage element module assembly 15. The multiple energy storage element modules 20 included in the energy storage element unit 10 may have different configurations or may have the same configuration. However, from the viewpoint of improving versatility, it is preferable that the multiple energy storage element modules 20 have the same configuration, and it is preferable that they include at least the same components (for example, the cell 30 and case 18 described later). In the illustrated example, the multiple energy storage element modules 20 have the same configuration.

[0114] Each energy storage element module 20 has a plurality of cells 30 and a case 18 that houses the plurality of cells 30. A cell 30 is the smallest unit treated as an energy storage element. The cell 30 can be of various types, for example, a lithium-ion secondary battery. Figure 18 shows a plurality of cells 30 contained in one energy storage element module 20, and Figure 19 shows a single cell 30. The plurality of cells 30 contained in one energy storage element module 20 may have the same configuration as each other, or they may have different configurations as each other.

[0115] As shown in Figures 18 and 19, the cell 30 has a flattened shape. In plan view (observed from the first direction DA), the cell 30 has a substantially rectangular shape. The cell 30 has a short side in the second direction DB and a long side in the third direction DC. Multiple cells 30 are stacked in the stacking direction. In the illustrated example, the stacking direction of the cell 30 is parallel to the first direction DA. The cell 30 has a central portion 31C located in the center and a peripheral portion 31E surrounding the central portion 31C. The thickness of the central portion 31C is greater than the thickness of the peripheral portion 31E. In the illustrated example, the cell 30 bulges outwards in the central portion 31C toward one side in the first direction DA. Multiple cells 30 are stacked such that the central portions 31C face each other at least partially in the first direction DA. The cell 30 shown in Figure 19 comprises a plurality of electrode plates 32, including a positive electrode plate and a negative electrode plate; an outer casing 33 that houses the plurality of electrode plates 32; and tabs 35 that are electrically connected to the electrode plates 32 and extend to the outside of the outer casing 33. The cell 30 has a pair of tabs 35. The pair of tabs 35 each function as either a positive electrode terminal or a negative electrode terminal.

[0116] Cell 30 has a generally symmetrical configuration with reference planes along the first direction DA and the third direction DC that pass through the center in the second direction DB. Furthermore, cell 30 has a generally symmetrical configuration with reference planes along the first direction DA and the second direction DB that pass through the center in the third direction DC.

[0117] The numerous cells 30 contained in a single energy storage element module 20 are electrically connected to each other in series or parallel by the electrical connection of their tabs 35. The tabs 35 of the numerous cells 30 are electrically connected to each other using electrode members, for example (not shown). By appropriately setting the number of cells 30 and their connections in series and parallel, the output from a single cell 30 can be set to a desired voltage and capacity. In the illustrated example, a single energy storage element module 20 contains 16 cells 30. In particular, in the example shown in Figure 18, eight pairs of parallel-connected cells 30 are connected in series.

[0118] As shown in Figure 17, the energy storage element module 20 has a case 18 for housing multiple cells. The case 18 defines a storage space for housing multiple cells on its inner surface. The case 18 has a case body 40 and a cover 60. The cover 60 is removable from the case body 40.

[0119] Each of the cases 18 included in the energy storage element unit 10 has a case body 40 and a cover 60, which are formed using, for example, an insulating material. The cover 60 as a whole can be integrally molded from an insulating resin material. The case body 40 as a whole can be integrally molded from an insulating resin material.

[0120] As an example, each of the cases 18 included in the energy storage element unit 10 is made of a resin material. In a case 18 having a case body 40 and a cover 60 as shown in Figure 17, the case body 40 and the cover 60 are made of a resin material. The resin material that makes up the case 18 is, for example, the same resin material as the resin plate 91.

[0121] In the energy storage element unit 10 of this embodiment, the multiple through holes 94 through which the shaft portion 96a of the screw 96 passes when fixing the resin plate 91 and the metal plate 92 to each other include one reference through hole 94a and multiple wide through holes 94b. This allows the shaft portion 96a to shift inside the wide through holes 94b in response to the thermal expansion of the resin plate 91. This suppresses distortion in the thermally expanded resin plate 91. Therefore, according to the energy storage element unit 10 of this embodiment, it is possible to use resin as the material for the storage box 11 while allowing the thermal expansion of the resin. In particular, it is possible to use the resin plate 91 as part of the wall portion 13 of the storage box 11 while allowing the thermal expansion of the resin plate 91.

[0122] Furthermore, in the energy storage element unit 10 according to this embodiment, the storage box 11 is composed of multiple members. In particular, in the energy storage element unit 10 according to this embodiment, the storage box 11 has multiple wall portions 13. Here, in the energy storage element unit 10 according to this embodiment, at least a part of the connecting portion 911b overlaps a part of the second resin plate 912 in the thickness direction of the second resin plate 912. This prevents the inside of the storage box 11 from being visible between the first wall portion 13d and the second wall portion 13e, thereby improving the aesthetic appearance of the energy storage element unit 10. In particular, in the energy storage element unit 10, it is sometimes required to avoid directly joining the first resin plate 911 and the second resin plate 912 in order to suppress distortion of the resin plate 91 when the resin plate 91 expands due to heat. In this embodiment, even if the first resin plate 911 and the second resin plate 912 are not directly joined, it is possible to prevent the inside of the storage box 11 from being visible between the edge of the connecting portion 911b and the edge of the second resin plate 912, thereby improving the aesthetic appearance of the energy storage element unit 10.

[0123] Based on the above, the energy storage element unit 10 according to this embodiment can improve the aesthetic appearance of the energy storage element unit 10 by suppressing distortion of the resin plate 91 when the resin plate 91 expands due to heat, while also preventing the inside of the storage box 11 from being visible through the gaps between the resin plates 91.

[0124] The embodiments of the present invention are not limited to those described above, but include various modifications that a person skilled in the art could conceive, and the effects of the present invention are not limited to those described above. In other words, various additions, modifications, and partial deletions are possible as long as they do not depart from the conceptual idea and spirit of the present invention derived from the claims and their equivalents. [Explanation of symbols]

[0125] 10 Energy Storage Element Unit 11 Storage Boxes 12 Frame section 13 Wall 13a Bottom wall 13b Upper wall part 13c Sidewall portion 91 Resin Board 92 Metal Plate

Claims

1. A storage box having multiple walls, A storage element unit comprising a plurality of energy storage element modules housed in the aforementioned storage box, The plurality of wall portions include a first wall portion and a second wall portion connected to the first wall portion, At least two of the plurality of wall portions, including the first wall portion and the second wall portion, are composed of a laminate including a resin plate and a metal plate. The resin plate is provided with either a plurality of through holes through which the shaft of a screw passes, or a plurality of screw holes through which the shaft passed through the plurality of through holes is screwed in, and the metal plate is provided with the other of the plurality of through holes or the plurality of screw holes, The plurality of through holes include one standard through hole and a plurality of wide through holes, Each of the aforementioned wide through-holes has a width greater than the diameter of the reference through-hole in the direction in which each of the wide through-holes and the reference through-hole are aligned. An energy storage element unit in which the edge of the first resin plate, which is included in the first wall portion, and the edge of the second resin plate, which is included in the second wall portion, face each other and are not directly joined to each other.

2. The energy storage element unit according to claim 1, wherein the positional relationship between the first metal plate, which is the metal plate included in the first wall portion, and the second metal plate, which is the metal plate included in the second wall portion, is fixed, thereby fixing the positional relationship between the first resin plate and the second resin plate.

3. A storage box having multiple wall sections, Multiple energy storage element modules housed in the aforementioned storage box, A storage element unit comprising a decorative panel provided on the storage box and covering one of the multiple wall sections, At least one of the aforementioned plurality of wall portions is composed of a laminate including a resin plate and a metal plate, The resin plate is provided with either a plurality of through holes through which the shaft of a screw passes, or a plurality of screw holes through which the shaft passed through the plurality of through holes is screwed in, and the metal plate is provided with the other of the plurality of through holes or the plurality of screw holes, The plurality of through holes include one standard through hole and a plurality of wide through holes, Each of the aforementioned wide through-holes has a width greater than the diameter of the reference through-hole in the direction in which each of the wide through-holes and the reference through-hole are aligned. The aforementioned decorative panel has at least a plurality of decorative wall sections, including a first decorative wall section and a second decorative wall section. The materials of the first decorative wall section and the second decorative wall section are resin materials. A storage element unit in which the edge of the first decorative wall section and the edge of the second decorative wall section face each other and are not directly joined to each other.

4. A storage box having multiple wall sections, A storage element unit comprising a plurality of energy storage element modules housed in the aforementioned storage box, At least one of the aforementioned plurality of wall portions is composed of a laminate including a resin plate and a metal plate, The resin plate is provided with either a plurality of through holes through which the shaft of a screw passes, or a plurality of screw holes through which the shaft passed through the plurality of through holes is screwed in, and the metal plate is provided with the other of the plurality of through holes or the plurality of screw holes, The plurality of through holes include one standard through hole and a plurality of wide through holes, Each of the aforementioned wide through-holes has a width greater than the diameter of the reference through-hole in the direction in which each of the wide through-holes and the reference through-hole are aligned. A storage element unit in which the width of the shaft portion of the screw that passes through a plurality of wide through holes, in the direction in which each of the wide through holes and the reference through hole are aligned, is smaller than the width of the wide through hole through which the shaft portion passes, in the direction in which each of the wide through holes and the reference through hole are aligned.

5. The energy storage element unit according to claim 4, wherein the width of the shaft portion of the screw that passes through the plurality of wide through holes, in a direction perpendicular to the axial direction of the screw, is large enough to allow the shaft portion of the screw to pass through the reference through hole.

6. The energy storage element unit according to claim 4 or 5, wherein the width of the shaft portion of the screw that passes through the plurality of wide through holes in a direction perpendicular to the axial direction of the screw is equal to the width of the shaft portion of the screw that passes through the reference through hole in a direction perpendicular to the axial direction of the screw.

7. The energy storage element unit according to any one of claims 1 to 6, wherein the reference through-hole fixes the position of the shaft portion passed through the reference through-hole.

8. The wall portion formed from the laminate has a pair of first sides extending in a first stretching direction and a pair of second sides extending in a second stretching direction perpendicular to the first stretching direction. The aforementioned plurality of wide through holes include a first wide through hole, a second wide through hole, and a third wide through hole. The first wide through-hole and the reference through-hole are aligned in the first extension direction, The first wide through-hole has a width greater than the diameter of the reference through-hole in the first extending direction. The second wide through-hole and the reference through-hole are aligned in the second extension direction, The second wide through-hole has a width greater than the diameter of the reference through-hole in the second extending direction. The third wide through-hole and the reference through-hole are located in different positions in the first and second extension directions. The energy storage element unit according to any one of claims 1 to 7, wherein the third wide through-hole has a diameter larger than the diameter of the reference through-hole.

9. The plurality of wall portions include a bottom wall portion, an upper wall portion facing the bottom wall portion, and a plurality of side wall portions connected to the bottom wall portion and the upper wall portion. The energy storage element unit according to any one of claims 1 to 8, wherein at least of the plurality of wall portions, the plurality of side wall portions, are made of the laminate.

10. The energy storage element unit according to claim 9, wherein in the side wall portion, the reference through hole is provided at a position closer to the upper wall portion than to the bottom wall portion.

11. The energy storage element unit according to any one of claims 1 to 10, wherein the resin plate is provided with the plurality of screw holes and the metal plate is provided with the plurality of through holes.

Images