Energy storage device

Abstract

This ensures the fixing strength of multiple stacked battery cells while suppressing an increase in the weight of the energy storage device and a deterioration in assembly ease. [Solution] The device comprises a total of eight rectangular cells stacked in the front-to-back direction, and support members that support these rectangular cells from the up-down and left-to-right directions intersecting the front-to-back direction. Each rectangular cell has a pair of adjacent acute first and second corners when viewed from the front-to-back direction, and the support members comprise a pair of first and second rod-shaped bodies that cover the first and second corners of the total of eight rectangular cells, respectively.

Description

Technical Field

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

Background Art

[0002] For example, Patent Document 1 describes a battery system used in an electric vehicle, a hybrid car, or the like. The battery system includes a plurality of battery units, and each battery unit has a battery laminate formed by laminating a plurality of unit cells.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the technique described in Patent Document 1, a battery laminate formed by laminating a plurality of unit cells is fixed using two end plates and four connectors. Thereby, while ensuring the fixing strength of the battery laminate, it has led to an increase in the weight of the battery unit and deterioration of the assemblability.

Means for Solving the Problems

[0005] The power storage device of the present disclosure includes a plurality of battery cells laminated in a first direction, and a support member that supports the plurality of battery cells from a second direction intersecting the first direction. The battery cell has a pair of acute-angled corners adjacent to each other when the battery cell is viewed from the first direction, and the support member includes a pair of first support members that respectively cover the pair of acute-angled corners of the plurality of battery cells.

Effects of the Invention

[0006] According to this disclosure, it is possible to ensure the fixing strength of multiple stacked battery cells while suppressing an increase in the weight and deterioration of the assembly of the energy storage device. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 shows an example of a vehicle. [Figure 2] Figure 2 is a perspective view of the battery module shown in Figure 1. [Figure 3] Figure 3 is a view taken along arrow A in Figure 2. [Figure 4] Figure 4 is a view taken along arrow B in Figure 2. [Figure 5] Figure 5 is an exploded perspective view of the battery module shown in Figure 2. [Figure 6] Figure 6 is a partially enlarged view corresponding to Figure 3, showing the first corner of the battery cell and the first rod-shaped body of the support member. [Figure 7] Figure 7 is a diagram corresponding to Figure 6, showing the state in which the first corner is covered with the first rod-shaped body. [Figure 8] Figure 8 illustrates the heat exchange efficiency of the battery module shown in Figure 2. [Figure 9] Figure 9 illustrates the heat exchange efficiency of the comparative battery module. [Modes for carrying out the invention]

[0008] Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

[0009] <Vehicle> Figure 1 shows an example of a vehicle. The vehicle 10 shown in Figure 1 is an electric vehicle. The vehicle 10 has a battery pack 11 equipped with multiple battery modules 30. Specifically, the battery pack 11 is installed in the floor portion 13 that forms the body 12 of the vehicle 10. The battery modules 30 correspond to the energy storage devices in this invention.

[0010] Furthermore, the vehicle 10 has an electric axle 16 equipped with an electric motor 14 and a differential mechanism 15. Specifically, the electric motor 14 is electrically connected to the battery pack 11 via an inverter 17. The differential mechanism 15 is connected to the axle 18. As a result, the wheels 19 fixed to the axle 18 are rotationally driven by the electric motor 14.

[0011] The battery pack 11 is temperature-adjustable by a temperature control mechanism 20. The temperature control mechanism 20 is located between the battery pack 11 and the floor section 13 and is in contact with the battery pack 11. Specifically, the temperature control mechanism 20 has a housing 21 through which liquid W (see Figure 8) flows. Here, the liquid W flowing inside the housing 21 is either cold water or hot water. As a result, the temperature control mechanism 20 manages the temperature of the battery pack 11 so that it stays within a specified temperature range. Therefore, the battery pack 11 can perform adequately regardless of the ambient temperature.

[0012] <Battery Module> Figure 2 is a perspective view of the battery module shown in Figure 1. Figure 3 is a view taken along arrow A in Figure 2. Figure 4 is a view taken along arrow B in Figure 2. Figure 5 is an exploded perspective view of the battery module shown in Figure 2.

[0013] As shown in Figure 1, the battery pack 11 includes a flat-shaped battery case 22 that can be installed in the narrow floor section 13. Multiple battery modules 30 are neatly arranged and housed inside the battery case 22. The multiple battery modules 30 are electrically connected to each other in parallel or in series inside the battery case 22.

[0014] As shown in FIGS. 2 to 5, the battery module 30 has a plurality of rectangular cells 31 formed in a thick plate shape and trapezoid shape. In the present embodiment, the battery module 30 is formed by stacking a total of eight rectangular cells 31 in the front-rear direction FB. And the rectangular cell 31 has a cell cover 32 forming its outer contour, and inside the cell cover 32, a positive electrode, a negative electrode, a separator, etc. formed in a film shape are accommodated. Note that the cell cover 32 is made of a 3000 series aluminum alloy whose strength is enhanced by adding, for example, manganese (Mn).

[0015] Note that the front-rear direction FB corresponds to the first direction in the present invention. Also, the rectangular cell 31 corresponds to the battery cell in the present invention. Further, the cell cover 32 corresponds to the casing in the present invention.

[0016] Also, the battery module 30 includes a support member 40 that collectively supports the total of eight stacked rectangular cells 31. Here, the support member 40 is formed in a substantially ladder shape and has a function of holding the stacked rectangular cells 31 so as not to rattle and not to separate. Specifically, as shown in FIG. 2, the support member 40 can support the stacked rectangular cells 31 from three directions: the front-rear direction FB, the up-down direction TB, and the left-right direction LR.

[0017] <Rectangular cell> The cell cover 32 forming the rectangular cell 31 is formed in a thick trapezoid shape having a total of six surfaces. Specifically, the cell cover 32 includes a front surface 32a and a rear surface 32b formed in a trapezoid shape, an upper bottom surface 32c and a lower bottom surface 32d that are parallel to each other, and a first leg surface 32e and a second leg surface 32f that are inclined at a predetermined angle so as to be mirror-symmetrical to each other. That is, the cell cover 32 is formed in a thick so-called "isosceles trapezoid" shape as shown in FIG. 5.

[0018] Here, as shown in FIGS. 2 to 5, the stacking direction (alignment direction) of the square cells 31 is defined as the front-back direction FB. Also, the facing direction of the upper bottom surface 32c and the lower bottom surface 32d of the cell cover 32 that are parallel to each other is defined as the up-down direction TB. Further, the direction in which the first leg surface 32e and the second leg surface 32f of the cell cover 32 face each other is defined as the left-right direction LR. Note that the up-down direction TB and the left-right direction LR that intersect the front-back direction FB correspond to the second direction in the present invention.

[0019] As shown in FIG. 3, when the cell cover 32 is viewed from the front-back direction FB, the cell cover 32 includes a first corner portion 33 and a second corner portion 34 that form acute angles, and a third corner portion 35 and a fourth corner portion 36 that form obtuse angles.

[0020] Specifically, the first corner portion 33 and the second corner portion 34 are adjacent to each other in the left-right direction LR when the square cell 31 is viewed from the front-back direction FB. The first corner portion 33 is formed by the upper bottom surface 32c and the first leg surface 32e, and the angle formed by the upper bottom surface 32c and the first leg surface 32e is α degrees (about 75 degrees). Also, the second corner portion 34 is formed by the upper bottom surface 32c and the second leg surface 32f, and the angle formed by the upper bottom surface 32c and the second leg surface 32f is also α degrees.

[0021] Furthermore, the third corner portion 35 and the fourth corner portion 36 are adjacent to each other in the left-right direction LR when the square cell 31 is viewed from the front-back direction FB. The third corner portion 35 is formed by the lower bottom surface 32d and the first leg surface 32e, and the angle formed by the lower bottom surface 32d and the first leg surface 32e is β degrees (about 105 degrees). Also, the fourth corner portion 36 is formed by the lower bottom surface 32d and the second leg surface 32f, and the angle formed by the lower bottom surface 32d and the second leg surface 32f is also β degrees.

[0022] Note that the pair of acute first and second corner portions 33 and 34 respectively correspond to the corner portions in the present invention. Also, the upper bottom surface 32c that forms the first and second corner portions 33 and 34 corresponds to the first outer surface in the present invention. Further, the first and second leg surfaces 32e and 32f that form the first and second corner portions 33 and 34 respectively correspond to the second outer surfaces in the present invention.

[0023] <Support member> As shown in Figures 2 to 4, the support member 40, which is formed in a roughly ladder-like shape, is positioned above a total of eight rectangular cells 31. In other words, the support member 40 supports the sides of the eight rectangular cells 31 where a pair of acute first and second corners 33 and 34 are provided, bringing them together into one unit.

[0024] The support member 40 comprises a pair of long first rod-shaped bodies 41 and second rod-shaped bodies 42, a single main support rod 43 that is shorter than the first and second rod-shaped bodies 41 and 42, and a pair of first sub-support rods 44 and second sub-support rods 45 that are approximately the same length as the main support rod 43. Here, the first and second rod-shaped bodies 41 and 42, the main support rod 43, and the first and second sub-support rods 44 and 45 are all formed into a roughly rod shape by sheet metal processing of metal plates.

[0025] The first rod-shaped body 41 is positioned on the upper and left side of the battery module 30. When viewed from the front-rear direction FB, the first rod-shaped body 41 is bent at an acute angle to form a V-shape and covers the first corner portion 33 of the cell cover 32. Specifically, the first rod-shaped body 41 has a first support plate portion 41a and a second support plate portion 41b. The first support plate portion 41a has a first support surface 41c that makes surface contact with the upper bottom surface 32c that forms the first corner portion 33, and the second support plate portion 41b has a second support surface 41d that makes surface contact with the first leg surface 32e that forms the first corner portion 33.

[0026] Furthermore, the second rod-shaped body 42 is positioned on the upper and right side of the battery module 30, and when viewed from the front-rear direction FB, the second rod-shaped body 42 is bent at an acute angle to form a V shape and covers the second corner portion 34 of the cell cover 32. Specifically, the second rod-shaped body 42 has a first support plate portion 42a and a second support plate portion 42b. The first support plate portion 42a has a first support surface 42c that makes surface contact with the upper bottom surface 32c that forms the second corner portion 34, and the second support plate portion 42b has a second support surface 42d that makes surface contact with the second leg surface 32f that forms the second corner portion 34.

[0027] Here, the first rod-shaped body 41 and the second rod-shaped body 42 are arranged in a mirror-image symmetrical manner across the rectangular cell 31 in the left-right direction LR of the battery module 30, as shown in Figure 3. In the state before the first and second rod-shaped bodies 41 and 42 are attached to the first and second corner portions 33 and 34 respectively (see Figure 6), that is, before the elastic deformation of the first and second rod-shaped bodies 41 and 42, the angles between the first support surface 41c and the second support surface 41d, and the angles between the first support surface 42c and the second support surface 42d are γ degrees (approximately 70 degrees), which is smaller than the angle (α degrees) between the upper base surface 32c and the first and second leg surfaces 32e and 32f (γ degrees < α degrees).

[0028] Thus, the first and second rod-shaped bodies 41 and 42 support a total of eight rectangular cells 31 from the vertical direction TB and the horizontal direction LR, and correspond to the first support members in the present invention, respectively. Furthermore, the first support surfaces 41c and 42c, which are in surface contact with the upper bottom surface 32c, correspond to the first inner surfaces in the present invention, respectively. In addition, the second support surfaces 41d and 42d, which are in surface contact with the first and second leg surfaces 32e and 32f, respectively, correspond to the second inner surfaces in the present invention.

[0029] As shown in Figures 2 and 4, the main support rod 43 is positioned at the longitudinal center of the first and second rod-shaped bodies 41 and 42. Specifically, both longitudinal ends of the main support rod 43 are fixed by welding to the longitudinal center of the first support plate portions 41a and 42a that form the first and second rod-shaped bodies 41 and 42, respectively. As a result, the spacing between the first and second rod-shaped bodies 41 and 42 is maintained at a specified dimension in the left-right direction (LR) of the battery module 30, and the first and second rod-shaped bodies 41 and 42 support the first and second corner portions 33 and 34 of the total of eight rectangular cells 31 without rattling.

[0030] As shown in FIGS. 4 and 5, the first and second sub-supporting rods 44 and 45 are respectively arranged at the front and rear ends of the first and second rod-shaped bodies 41 and 42 in the front-rear direction FB of the battery module 30. Specifically, both longitudinal ends of the first sub-supporting rod 44 are fixed to the front ends of the second support plate portions 41b and 42b forming the first and second rod-shaped bodies 41 and 42 by welding, respectively. Also, both longitudinal ends of the second sub-supporting rod 45 are fixed to the rear ends of the second support plate portions 41b and 42b forming the first and second rod-shaped bodies 41 and 42 by welding, respectively.

[0031] Here, as shown in FIG. 4, the length dimension L of the first and second rod-shaped bodies 41 and 42 along the front-rear direction FB of the battery module 30 is slightly smaller than the stacking dimension T of a total of eight square cells 31 (L < T). Thereby, the first and second sub-supporting rods 44 and 45 support a total of eight square cells 31 without rattling in the front-rear direction FB (the stacking direction of the plurality of square cells 31) of the battery module 30. Note that the first and second sub-supporting rods 44 and 45 correspond to the second supporting members in the present invention.

[0032] Thus, the first and second rod-shaped bodies 41 and 42 support the first and second corner portions 33 and 34 of a total of eight square cells 31, and the first and second sub-supporting rods 44 and 45 support a total of eight square cells 31 in their stacking direction. That is, the supporting member 40 supports only the upper side (one side) of the battery module 30 from three directions: the vertical direction TB, the horizontal direction LR, and the front-rear direction FB.

[0033] Furthermore, both longitudinal ends of the main supporting rod 43 are fixed to the longitudinal central portions of the first support plate portions 41a and 42a by welding, respectively, and both longitudinal ends of the first and second sub-supporting rods 44 and 45 are fixed to the front and rear ends of the second support plate portions 41b and 42b by welding, respectively. Thereby, the supporting member 40 ensures sufficient torsional rigidity of the battery module 30.

[0034] <Assembly Procedure> Next, the assembly procedure of the battery module 30 will be described in detail with reference to FIGS. 3, 5 to 7.

[0035] FIG. 6 is a partial enlarged view corresponding to FIG. 3 showing the first corner portion of the battery cell and the first rod-shaped body of the support member. FIG. 7 is a view corresponding to FIG. 6 showing a state where the first corner portion is covered with the first rod-shaped body.

[0036] In FIGS. 6 and 7, only the first corner portion 33 and the first rod-shaped body 41 are shown, but the second corner portion 34 and the second rod-shaped body 42 (not shown) are assembled in the same manner as the first corner portion 33 and the first rod-shaped body 41.

[0037] First, as shown by the arrow M1 in FIG. 5, a total of eight rectangular cells 31 are abutted against each other and stacked. At this time, the rear surface 32b of the front rectangular cell 31 and the front surface 32a of the rear rectangular cell 31 are abutted against each other. At that time, the positions of the first, second, third, and fourth corner portions 33, 34, 35, and 36 of each rectangular cell 31 are aligned.

[0038] Next, as shown by the arrow M2 in FIGS. 5 to 7, the first and second rod-shaped bodies 41 and 42 are faced to the first and second corner portions 33 and 34 of the stacked rectangular cells 31. Then, while abutting the first support surfaces 41c and 42c of the first and second rod-shaped bodies 41 and 42 against the upper bottom surface 32c of the stacked cell cover 32, the second support surfaces 41d and 42d of the first and second rod-shaped bodies 41 and 42 are respectively abutted against the first and second leg surfaces 32e and 32f of the stacked cell cover 32.

[0039] At this time, the first and second rod-shaped bodies 41 and 42 are elastically deformed as shown by the two-dot chain line arrow OP in FIG. 7. That is, the hardness H1 (HV) of the first and second rod-shaped bodies 41 and 42 is lower than the hardness H2 (HV) of the cell cover 32 (H1 < H2). Specifically, the angles formed by the first support plate portion 41a and the second support plate portion 41b and the angles formed by the first support plate portion 42a and the second support plate portion 42b (γ degrees: see FIG. 6) become α degrees of the first and second corner portions 33 and 34 when the first and second rod-shaped bodies 41 and 42 are pushed apart.

[0040] As a result, as shown in Figure 7, the first support surfaces 41c and 42c of the first support plate portions 41a and 42a are pressed against the upper bottom surface 32c with a pressing force F1, as indicated by the white arrows. Also, the second support surfaces 41d and 42d of the second support plate portions 41b and 42b are pressed against the first and second leg surfaces 32e and 32f, respectively, with a pressing force F2, as indicated by the white arrows.

[0041] Subsequently, with the first and second rod-shaped bodies 41 and 42 abutting against the first and second corner portions 33 and 34, respectively, the longitudinal ends of the main support rod 43 are fixed by welding to the longitudinal centers of the first support plate portions 41a and 42a, respectively, as shown by arrow M3 in Figure 5.

[0042] Furthermore, as shown by arrow M4 in Figure 5, the longitudinal ends of the first and second sub-support rods 44 and 45 are fixed to the front and rear ends of the second support plate sections 41b and 42b, respectively, by welding. This completes the assembly of the battery module 30.

[0043] In this way, by elastically deforming the first and second rod-shaped bodies 41 and 42 and bringing them into contact with the first and second corner portions 33 and 34, a so-called "wedge effect" is obtained. That is, the first and second rod-shaped bodies 41 and 42 are in close contact with the first and second corner portions 33 and 34 without any wobbling.

[0044] Furthermore, since the length dimension L of the first and second rod-shaped bodies 41 and 42 is slightly smaller than the stacking dimension T of the rectangular cell 31, the support member 40 supports the stacked rectangular cell 31 without wobbling in the stacking direction.

[0045] <Heat exchange efficiency of battery modules> Next, the heat exchange efficiency of the battery module 30 will be explained in detail using Figures 8 and 9.

[0046] Figure 8 illustrates the heat exchange efficiency of the battery module shown in Figure 2. Figure 9 illustrates the heat exchange efficiency of a comparative battery module.

[0047] In the comparative example battery module BM shown in Figure 9, a structure is adopted in which rectangular (four corners at 90 degrees) prismatic cells SC are stacked in the front-to-back direction FB, and the entire circumference of the stacked prismatic cells SC is supported by a support member SM.

[0048] As shown in Figure 8, in the battery module 30 of this embodiment, the support member 40 is positioned only on the upper side of the multiple rectangular cells 31. Therefore, nothing is present on the lower side of each rectangular cell 31, leaving it exposed. In other words, the lower bottom surface 32d of each cell cover 32 can directly contact the battery case 22. Consequently, as shown by the thick solid and thick dashed arrows, heat exchange can be performed with high efficiency between the battery module 30 and the temperature control mechanism 20. In addition, a thin TIM (Thermal Interface Material) may be placed between the lower bottom surface 32d of the cell cover 32 and the battery case 22 to improve the contact between them.

[0049] In contrast, as shown in Figure 9, in the comparative example battery module BM, when the battery module BM is viewed from the front-to-back direction FB, the support member SM is provided around the entire circumference of the prismatic cell SC. Therefore, a part of the support member SM or space is interposed between the lower side of the prismatic cell SC and the battery case 22. Consequently, it is necessary to place a relatively thick TIM material ST in the space between the lower side of the prismatic cell SC and the battery case 22. Therefore, as shown by the thin solid and thin dashed arrows, the heat exchange between the battery module BM and the temperature control mechanism 20 is less efficient compared to this embodiment (see Figure 8).

[0050] Thus, it was found that the battery module 30 of this embodiment is also advantageous from the viewpoint of heat exchange efficiency.

[0051] As described in detail above, according to this embodiment, the structure comprises a total of eight rectangular cells 31 stacked in the front-rear direction FB, and support members 40 that support these rectangular cells 31 from the vertical direction TB and the left-right direction LR intersecting the front-rear direction FB. Each rectangular cell 31 has a pair of adjacent acute first and second corners 33 and 34 when viewed from the front-rear direction FB, and the support members 40 comprises a pair of first and second rod-shaped bodies 41 and 42 that cover the first and second corners 33 and 34 of the total of eight rectangular cells 31, respectively.

[0052] This ensures the fixing strength of the eight stacked rectangular cells 31, while also suppressing an increase in the weight of the battery module 30 and a deterioration in assembly ease.

[0053] Furthermore, according to this embodiment, the first and second corner portions 33 and 34 have an upper base surface 32c and first and second leg surfaces 32e and 32f, and the first and second rod-shaped bodies 41 and 42 have first support surfaces 41c and 42c that are in surface contact with the upper base surface 32c and second support surfaces 41d and 42d that are in surface contact with the first and second leg surfaces 32e and 32f.

[0054] This allows the first and second rod-shaped bodies 41 and 42 to make surface contact with the first and second corner portions 33 and 34 at a total of four locations. Therefore, the first and second rod-shaped bodies 41 and 42 can support the stacked prismatic cells 31 without rattling in both the vertical TB direction and the horizontal LR direction. Thus, sufficient vibration resistance of the battery module 30 can be ensured.

[0055] Furthermore, according to this embodiment, the first support surfaces 41c, 42c and the second support surfaces 41d, 42d of the first and second rod-shaped bodies 41, 42 are pressed against the upper bottom surface 32c and the first and second leg surfaces 32e, 32f of the first and second corner portions 33, 34, respectively.

[0056] This allows the first and second rod-shaped bodies 41 and 42 and the first and second corner portions 33 and 34 to be brought into close contact with each other through a so-called "wedge effect." Therefore, the first and second rod-shaped bodies 41 and 42 can support the first and second corner portions 33 and 34 with less wobbling.

[0057] Furthermore, according to this embodiment, the support member 40 has first and second sub-support rods 44 and 45, the ends of which are fixed to the first and second rod-shaped bodies 41 and 42, respectively, and which support a total of eight rectangular cells 31 from the front-rear direction FB.

[0058] As a result, the support member 40 can support a total of eight rectangular cells 31 without rattling, even in the front-to-back direction FB (the stacking direction of the rectangular cells 31) of the battery module 30. Therefore, the stacked rectangular cells 31 are supported by the support member 40 from three directions: the front-to-back direction FB, the up-and-down direction TB, and the left-to-right direction LR, which in turn increases the torsional rigidity of the battery module 30.

[0059] This disclosure is not limited to the embodiments described above, and it goes without saying that various modifications are possible without departing from its essence. In the embodiments described above, a battery module 30 is shown mounted on a vehicle 10 which is an electric vehicle, but the invention is not limited to this, and the battery module 30 can also be used in other devices.

[0060] Furthermore, although the above-described embodiment shows a battery module 30 equipped with a total of eight rectangular cells 31, the number of rectangular cells 31 can be set to a total of seven or fewer, or to a total of nine or more, depending on the required battery capacity (kWh).

[0061] Furthermore, although the above-described embodiment shows the temperature control mechanism 20 positioned below the battery module 30, it is not limited to this configuration. The temperature control mechanism 20 can also be positioned above the battery module 30, or the battery module 30 can be placed vertically and the temperature control mechanism 20 positioned to the side of the battery module 30.

[0062] Furthermore, in the embodiment described above, the angles of the first and second corners 33 and 34 are both set to the same acute angle of α degrees. However, the embodiment is not limited to this, and the angles of the first and second corners 33 and 34 can be different from each other as long as they are acute angles. However, the angles of the first and second rod-shaped bodies 41 and 42 should also be matched to the angles of the first and second corners 33 and 34. In other words, it is sufficient that the angles of the first and second rod-shaped bodies 41 and 42 do not deviate from (come out of) the first and second corners 33 and 34.

[0063] Furthermore, the angles of the first and second corners 33 and 34 and the angles of the first and second rods 41 and 42 may be adjusted to match the hardness of the first and second rods 41 and 42 and the hardness of the cell cover 32. In this case, for example, if the first and second rods 41 and 42 and the cell cover 32 are made of high hardness, they will become less prone to deformation. Therefore, the angles of the first and second corners 33 and 34 and the angles of the first and second rods 41 and 42 can be made more acute angles, closer to right angles.

[0064] Furthermore, in the above-described embodiment, the components forming the support member 40 (first and second rod-shaped bodies 41, 42, main support rod 43, and first and second sub-support rods 44, 45) are shown assembled by welding to one another. However, the invention is not limited to this, and each component can also be assembled by screwing, riveting, or other methods. [Explanation of symbols]

[0065] 30...Battery module (energy storage device), 31...Porcelain cell (battery cell), 32...Cell cover (casing), 32c...Top bottom surface (first outer surface), 32e...First leg surface (second outer surface), 32f...Second leg surface (second outer surface), 33...First corner (corner), 34...Second corner (corner), 40...Support member, 41...First rod-shaped body (first support member), 41c...First support surface (first inner surface), 41d...First 2 support surface (second inner surface), 42...second rod-shaped body (first support member), 42c...first support surface (first inner surface), 42d...second support surface (second inner surface), 44...first sub-support rod (second support member), 45...second sub-support rod (second support member), FB...front-back direction (first direction), LR...left-right direction (second direction), TB...up-down direction (second direction), H1...hardness of the first and second rod-shaped bodies, H2...hardness of the cell cover

Claims

1. Multiple battery cells stacked in the first direction, A support member that supports the plurality of battery cells from a second direction intersecting the first direction, Equipped with, The battery cell has a pair of adjacent acute corners when viewed from the first direction. The support member comprises a pair of first support members that cover each of the pair of acute-angled corners of the plurality of battery cells. Energy storage device.

2. In the energy storage device according to claim 1, The aforementioned corner portion has a first outer surface and a second outer surface, The first support member includes a first inner surface that is in surface contact with the first outer surface and a second inner surface that is in surface contact with the second outer surface. Energy storage device.

3. In the energy storage device according to claim 2, The first inner surface and the second inner surface of the first support member are pressed against the first outer surface and the second outer surface of the corner, respectively. Energy storage device.

4. In the energy storage device according to any one of claims 1 to 3, The aforementioned support member is The second support member has both ends fixed to a pair of first support members and supports a plurality of battery cells from a first direction. Energy storage device.

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