Power storage device and power storage module

Abstract

To provide a new power storage device with excellent heat dissipation properties.SOLUTION: A power storage device 100 disclosed herein includes a battery case 10 having a pair of side walls 12b, and an electrode body 20 housed in the battery case 10. The battery case 10 includes a corrugated plate portion 13 on at least one of the pair of side walls 12b, the corrugated plate portion having an uneven inner and outer surfaces.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a power storage device and a power storage module.

Background Art

[0002] Conventionally, in power sources for vehicle drive and the like, a power storage module formed by electrically connecting a plurality of power storage devices has been widely used in order to increase the capacity and output. In the power storage module, if the power storage device generates heat during charging and discharging and becomes excessively hot, or if there is a temperature variation among the plurality of power storage devices in the power storage module, the inherent power storage performance may not be exhibited. As related prior art documents, Patent Documents 1 to 4 are cited.

[0003] For example, Japanese Patent Application Laid-Open No. 2011-192642 discloses a power storage module including a plurality of power storage devices arranged along a predetermined arrangement direction, and a cooling member disposed between adjacent power storage devices in the arrangement direction and having a flow path through which a cooling medium can flow. Japanese Patent Application Laid-Open No. 2011-192642 describes that the power storage device can be efficiently cooled by the cooling member and the variation in the performance of the power storage device can be suppressed. Further, for example, Japanese Patent Application Laid-Open No. 2012-243597 discloses providing protrusions on the surface of a battery case to increase the specific surface area and using it as a heat sink (to improve heat dissipation).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, according to the study by the present inventor, for example, when a cooling member is included in a power storage module as in Japanese Patent Application Laid-Open No. 2011-192642, or when protrusions are provided on the surface of a battery case as in Japanese Patent Application Laid-Open No. 2012-243597, the power storage module becomes heavier as a whole accordingly. In addition, the manufacturing cost increases due to an increase in the number of parts and the amount of materials used. Therefore, there is still room for improvement in the above technologies.

[0006] The present invention has been made in view of the above circumstances, and its main object is to provide a new power storage device having excellent heat dissipation properties.

Means for Solving the Problems

[0007] According to the present invention, there is provided a power storage device including a battery case having a pair of side walls and an electrode body housed in the battery case, wherein the battery case has a corrugated plate portion formed in a corrugated shape with uneven cross-section on at least one of the pair of side walls.

[0008] According to the present invention, by providing the corrugated plate portion, the specific surface area of the side wall can be increased, and relatively a large contact area with a cooling medium (for example, air) can be secured. Therefore, the heat dissipation property of the power storage device itself can be improved. In addition, weight reduction and cost reduction can be achieved as compared with the case of using a cooling member as described in Japanese Patent Application Laid-Open No. 2011-192642 or providing protrusions on the surface of the battery case as described in Japanese Patent Application Laid-Open No. 2012-243597.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0010] Hereinafter, preferred embodiments of the technology disclosed herein will be described with reference to the drawings as appropriate. Matters other than those specifically mentioned in this specification and necessary for the implementation of the present invention (for example, general configurations and manufacturing processes of power storage devices that do not characterize the present invention) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field. In the following drawings, members and parts having the same function are denoted by the same reference numerals, and redundant descriptions may be omitted or simplified. In this specification, the notation "A to B" indicating a range includes the meaning of "greater than A" and "less than B" in addition to the meaning of "A or more and B or less".

[0011] [Power Storage Module] FIG. 1 is a perspective view schematically showing a power storage module 500 according to an embodiment. The power storage module 500 includes, here, a plurality of power storage devices 100 and a restraint mechanism 300. The power storage module 500 does not have a cooling member as described in Japanese Patent Application Laid-Open No. 2011-192642 here. However, as long as the effects of the technology disclosed herein are not significantly impaired, the power storage module 500 may further include other members (for example, lightweight spacers, etc.).

[0012] In the following description, in the drawings, the reference signs L, R, F, Rr, U, and D represent left, right, front, rear, up, and down, respectively, and the reference signs X, Y, and Z in the drawings represent the short side direction (thickness direction), the long side direction orthogonal to the short side direction, and the up-down direction orthogonal to the short side direction and the long side direction of the power storage device 100, respectively. The short side direction X is also the arrangement direction of the power storage devices 100. The up-down direction is preferably the vertical direction. However, these are merely directions for convenience of explanation and do not limit the installation form of the power storage module 500 in any way.

[0013] The restraint mechanism 300 is a member that restrains a plurality of power storage devices 100. The restraint mechanism 300 is configured to apply a specified restraint load to a plurality of power storage devices 100 from the arrangement direction X. Here, the restraint mechanism 300 includes a pair of end plates 310, a pair of side plates 320, and a plurality of screws 330. The end plates 310 and the side plates 320 are preferably made of metal respectively. However, it may have a portion made of resin in part.

[0014] The pair of end plates 310 are arranged at both ends of the power storage module 500 in the arrangement direction X. The pair of end plates 310 sandwich a plurality of power storage devices 100 in the arrangement direction X. The pair of side plates 320 bridge the pair of end plates 310. The pair of side plates 320 are fixed to the end plates 310 by a plurality of screws 330 such that the restraint load is, for example, about 3 to 15 kN, preferably about 5 to 10 kN. Thereby, a restraint load is applied to a plurality of power storage devices 100 from the arrangement direction X, and the power storage module 500 is integrally held. However, the configuration of the restraint mechanism is not limited thereto. The restraint mechanism 300 may include, for example, a plurality of restraint bands, binding bars, etc. instead of the side plates 320 and the plurality of screws 330.

[0015] The power storage device 100 is a device capable of repeated charge and discharge. In this specification, the "power storage device" is a concept that includes so-called secondary batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and capacitors such as lithium-ion capacitors and electric double-layer capacitors. As shown in FIG. 1, a plurality of power storage devices 100 are arranged here between a pair of end plates 310 along the arrangement direction X (in other words, the thickness direction X of the power storage device 100). Note that FIG. 1 is merely an example, and the shape, size, number, arrangement, etc. of the plurality of power storage devices 100 are not limited to the embodiments disclosed in FIG. 1 and can be appropriately changed.

[0016] Although not shown here, when the power storage module 500 is used, a plurality of power storage devices 100 are electrically connected to each other by a conductive member such as a bus bar. The connection method is not particularly limited, and for example, it may be in series, parallel, or multi-series multi-parallel. In some embodiments, a plurality of power storage devices 100 are connected in series. In the case of series connection, deterioration of the performance of some of the power storage devices 100 is likely to lead to deterioration of the performance of the entire power storage module 500. Therefore, it is particularly effective to apply the technology disclosed here.

[0017] FIG. 2 is a perspective view schematically showing the power storage device 100. As can be seen from FIGS. 1 and 2, all of the plurality of power storage devices 100 are flat rectangular shapes and are of the same shape here. The plurality of power storage devices 100 are arranged in the arrangement direction X such that the long side walls 12b of the battery case 10 described later face each other. The power storage devices 100 adjacent to each other in the arrangement direction X have their long side walls 12b in contact (in direct contact) here. However, for example, when another member such as a spacer is interposed between the power storage devices 100 adjacent to each other in the arrangement direction X, it may be in contact with the other member.

[0018] FIG. 3 is a schematic longitudinal sectional view taken along line III-III of FIG. 2. As shown in FIG. 3, the power storage device 100 includes a battery case 10, an electrode body 20, a positive electrode terminal 30, and a negative electrode terminal 40. The power storage device 100 further includes a non-aqueous electrolyte (not shown) here. The power storage device 100 is configured by housing the electrode body 20 and the non-aqueous electrolyte in the battery case 10 to which the positive electrode terminal 30 and the negative electrode terminal 40 are attached. The power storage device 100 is a non-aqueous electrolyte secondary battery here, for example, a lithium ion secondary battery.

[0019] The electrode body 20 may be the same as the conventional one and is not particularly limited. Here, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode and a strip-shaped negative electrode are laminated via a strip-shaped separator and wound around a winding axis. The outer shape of the electrode body 20 is a flat shape. Here, the electrode body 20 is disposed inside the battery case 10 in a direction in which the winding axis is substantially parallel to the long side direction Y. However, in other embodiments, the electrode body 20 may be disposed inside the battery case 10 in a direction in which the winding axis is substantially parallel to the vertical direction Z. Further, the electrode body 20 may be a laminated electrode body in which a plurality of rectangular (typically rectangular) positive electrodes and a plurality of rectangular (typically rectangular) negative electrodes are stacked in an insulated state.

[0020] Although not shown, the electrode body 20 may be housed inside the battery case 10 in a state covered with a resin insulating sheet (electrode body holder). Also, the number of electrode bodies 20 disposed inside one battery case 10 may be one or two or more (plural). A positive electrode tab group 23 is attached to the positive electrode of the electrode body 20 and is electrically connected to the positive electrode terminal 30 via a positive electrode current collector 50. A negative electrode tab group 25 is attached to the negative electrode of the electrode body 20 and is electrically connected to the negative electrode terminal 40 via a negative electrode current collector 60.

[0021] The non-aqueous electrolyte may be the same as the conventional one and is not particularly limited. The non-aqueous electrolyte typically contains a non-aqueous solvent and a supporting salt (electrolyte salt, such as a Li salt or a Na salt). The non-aqueous electrolyte is typically liquid, but may also be gel-like. In other embodiments, the power storage device 100 may be provided with a solid electrolyte instead of the non-aqueous electrolyte. In that case, the separator can also be omitted.

[0022] The battery case 10 is a housing that houses the electrode body 20 and the non-aqueous electrolyte. As shown in FIG. 2, the battery case 10 here has an outer shape that is flat, bottomed, and substantially rectangular parallelepiped (rectangular). The material of the battery case 10 may be the same as the conventional one and is not particularly limited. The battery case 10 is preferably made of metal. For example, it is more preferably made of an iron alloy such as iron or stainless steel, aluminum, or an aluminum alloy. Among them, from the viewpoint of improving safety, a metal with a melting point of 1000 °C or higher, and further 1200 °C or higher is preferable, and in particular, an iron alloy, for example, stainless steel containing chromium and / or nickel is preferable. Note that the iron or iron alloy may be nickel-plated.

[0023] As shown in FIG. 3, the battery case 10 includes a case body 12 having an opening 12h and a sealing plate (lid body) 14 that seals the opening 12h. As shown in FIG. 2, the case body 12 includes a bottom wall 12a, a pair of long side walls 12b, and a pair of short side walls 12c. The bottom wall 12a is here substantially rectangular with a long side and a short side. The bottom wall 12a faces the sealing plate (lid body) 14. The bottom wall 12a is here flat, and both the inner surface (the surface on the side facing the electrode body 20, the same hereinafter) and the outer surface (the surface on the side not facing the electrode body 20) are flat. The bottom wall 12a does not have the corrugated plate portion 13 described later. In this specification, the term "substantially rectangular" includes not only a perfect rectangular shape (rectangular shape), but also, for example, a shape in which the corners connecting the long side and the short side of the rectangular shape are R-shaped, or a shape having a notch at the corner.

[0024] The pair of short side walls 12c extend from the short sides of the bottom wall 12a. The pair of short side walls 12c are arranged facing each other and connect the bottom wall 12a and the sealing plate 14. The short side wall 12c is flat here, and both the inner surface and the outer surface are flat. The short side wall 12c does not have the corrugated plate portion 13 described later. The pair of long side walls 12b extend from the long sides of the bottom wall 12a. The pair of long side walls 12b are arranged facing each other and connect the bottom wall 12a and the sealing plate 14. The long side wall 12b is an example of the side wall disclosed here.

[0025] Here, the long side wall 12b has a substantially rectangular shape having a long side (the side in the long side direction Y in FIG. 2) and a short side (the side in the vertical direction Z in FIG. 2). The length of the long side wall 12b in the long side direction Y is preferably 150 mm or more, more preferably 200 mm or more, and even more preferably 250 mm or more. Generally, the longer the length of the long side wall 12b in the long side direction Y, the more likely the heat dissipation decreases near the center in the long side direction Y of the long side wall 12b (for example, the central portion Am in FIG. 3). Therefore, it is particularly effective to apply the technology disclosed here. The length of the long side wall 12b in the long side direction Y may be, for example, 1000 mm or less, 500 mm or less. The long side wall 12b is preferably horizontally long. That is, it is preferable that the length in the long side direction Y is longer than the length in the vertical direction Z. The length of the long side wall 12b in the vertical direction Z is preferably 100 mm or more.

[0026] In a plan view, the area of the long side wall 12b is larger than the area of the short side wall 12c. Although not particularly limited, in the case of the high-capacity type power storage device 100 used for in-vehicle use or the like, the area of the long side wall 12b is generally 2 10000 mm or more, preferably 2 15000 mm or more, more preferably 2 20000 mm or more, even more preferably 2 25000 mm or more, and still more preferably 2The above is particularly preferable. When the area of the long side wall 12b is large in this way, the heat dissipation property tends to decrease at the central portion of the long side wall 12b. Therefore, it is particularly effective to apply the technology disclosed herein. Also, from the viewpoint of achieving the effects of the technology disclosed herein at a high level, the area of the long side wall 12b is generally 150,000 mm 2 or less, and preferably 2 100,000 mm

[0027] As shown in FIG. 2, in the technology disclosed herein, at least one of the pair of long side walls 12b has a corrugated plate portion 13 formed in a corrugated shape with uneven cross-section. By having the corrugated plate portion 13 on the long side wall 12b, the specific surface area of the long side wall 12b can be increased, and for example, compared with the case where the long side wall 12b is flat, a relatively large contact area with a cooling medium (for example, air) can be ensured. Thus, the heat dissipation property of the power storage device 100 itself can be improved. Also, weight reduction and cost reduction can be achieved compared with the case of using a cooling member as described in, for example, Japanese Patent Application Laid-Open No. 2011-192642, or providing protrusions on the long side wall 12b as described in Japanese Patent Application Laid-Open No. 2012-243597. As a result, the weight energy density of the power storage module 500 can also be improved.

[0028] In addition, according to the study by the present inventor, when protrusions as described in Japanese Patent Application Laid-Open No. 2012-243597 are provided on the long side wall 12b, when the electrode body 20 expands and contracts with charge and discharge, the thickness between the pair of long side walls 12b is difficult to follow, and an excessive load may be applied to the electrode body 20 or conversely the load may be insufficient. On the other hand, according to the technology disclosed herein, when the electrode body 20 expands and contracts with charge and discharge, the corrugated plate portion 13 elastically acts and the thickness between the pair of long side walls 12b becomes relatively easy to follow, so that it is also possible to stably apply a load to the electrode body 20. As a result, a decrease in the power storage performance (for example, an increase in resistance) of the power storage device 100 can be suppressed.

[0029] The long side wall 12b having the corrugated portion 13 is preferably made of metal as described above. For example, it is more preferably made of an iron alloy such as iron or stainless steel, aluminum, an aluminum alloy, or the like. Among these, an iron alloy is preferable, and stainless steel containing chromium and / or nickel is more preferable. Generally, iron or an iron alloy has a lower thermal conductivity than conventionally widely used aluminum and is difficult to use for the long side wall 12b that requires heat dissipation. However, according to the technology disclosed herein, such a material with a low thermal conductivity can also be suitably used.

[0030] FIG. 4 is a partial cross-sectional view schematically showing a part of the corrugated portion 13. As shown in FIG. 4, the corrugated portion 13 is formed in a corrugated shape with a concavo-convex cross-section. The corrugated portion 13 has a uniform thickness t here. Although not particularly limited, the thickness t of the corrugated portion 13 is preferably approximately 0.1 to 2 mm, more preferably 0.2 to 1 mm, and even more preferably 0.4 to 0.8 mm from the viewpoints of mechanical strength, rigidity, durability, and ease of production. The thickness t of the corrugated portion 13 may be the same as the thickness of the short side wall 12c, or may be thinner than the thickness of the short side wall 12c from the viewpoints of reducing raw material costs and ease of production.

[0031] Both the inner surface and the outer surface of the corrugated portion 13 are concavo-convex. In the corrugated portion 13, convex portions 13a protruding from the outer surface of the battery case 10 and convex portions 13b protruding from the inner surface of the battery case 10 are arranged alternately along the long side direction Y. The height d (the length in the short side direction X) of each of the convex portions 13a and 13b is the same here. Although not particularly limited, the height d can be set to approximately 1 to 100 mm, for example, about 5 to 50 mm. On the outer surface, a space S for allowing a cooling medium (for example, air) to flow is defined between adjacent convex portions 13a. As can be seen from FIG. 2, the space S extends linearly along the vertical direction Z. Both ends of the space S in the vertical direction Z are open. Although not particularly limited, the width w of the space S can be set to approximately 1 to 100 mm, for example, about 5 to 50 mm.

[0032] As shown in FIG. 4, the corrugated plate portion 13 is angularly corrugated here. The convex portions 13a and 13b are each formed with a substantially trapezoidal cross-section. The convex portions 13a and 13b each have a rib planar portion 13a1 and 13b1 that extend planar along the long side direction Y and the vertical direction Z (not shown in FIG. 4), and rib corner portions 13a2 and 13b2 that bend in an arc shape at both ends of the long side direction Y of the rib planar portions 13a1 and 13b1. However, in other embodiments, the corrugated plate portion 13 may not have the rib planar portions 13a1 and 13b1, and the cross-section may be a smooth wave shape, a triangular shape, a rectangular shape, or the like.

[0033] The corrugated plate portion 13 is preferably provided integrally with the long side wall 12b. Such a corrugated plate portion 13 can be formed by a conventionally known corrugating method, for example, press working, die casting, forging, casting, photolithography, laser processing, or the like. In one example, the corrugated plate portion 13 can be formed by corrugating a single metal plate used for the long side wall 12b by press working so that the convex portions 13a and 13b are arranged alternately.

[0034] In some embodiments, the corrugated plate portion 13 is preferably provided so as to face the entire electrode body 20 when viewed from the long side wall 12b side (the side in the array direction X). That is, the length of the corrugated plate portion 13 in the long side direction Y on the long side wall 12b is preferably the same as or longer than the length of the electrode body 20 in the long side direction Y. Also, the length of the corrugated plate portion 13 in the vertical direction Z on the long side wall 12b is preferably the same as or longer than the length of the electrode body 20 in the vertical direction Z. Thereby, the heat generated in the electrode body 20 can be efficiently released. Also, it becomes easier to apply a stable load to the electrode body 20.

[0035] In some embodiments, as shown in FIG. 2, when the long side wall 12b is divided into three equal parts in the long side direction Y to be divided into a pair of end portions Ae and a central portion Am, it is preferable that the corrugated plate portion 13 is provided at least in the central portion Am. According to the findings of the present inventor, heat tends to accumulate and become high temperature near the center in the long side direction Y. Therefore, it is particularly effective to apply the technology disclosed herein to the central portion Am. Further, from the viewpoint of exerting the effect of the technology disclosed herein at a high level, it is preferable that the corrugated plate portion 13 is provided in the pair of end portions Ae and the central portion Am, respectively. Among these, from the viewpoints of durability and ease of production, etc., it is preferable that the corrugated plate portion 13 is provided (continuously) across the pair of end portions Ae and the central portion Am. However, in other embodiments, the pair of end portions Ae in the long side direction Y may not have the corrugated plate portion 13. For example, the pair of end portions Ae may be flat plate-shaped, and both the inner surface and the outer surface may be flat.

[0036] In the present embodiment, as shown in FIG. 2, substantially the whole except for the outer edge portion of the long side wall 12b is constituted by the corrugated plate portion 13. In the corrugated plate portion 13, it is preferable that unevenness is arranged along the long side direction Y. However, in other embodiments, the unevenness may be arranged along the vertical direction Z. In the corrugated plate portion 13 of the present embodiment, a plurality of convex portions 13a extend along the vertical direction Z, respectively. The plurality of convex portions 13a have the same height d (not shown in FIG. 2, see FIG. 4) here. The plurality of convex portions 13a are arranged at regular intervals and extend along the vertical direction Z, respectively. In other words, the plurality of convex portions 13a are arranged in a stripe shape (striped shape) along the vertical direction Z.

[0037] However, in other embodiments, in the corrugated plate portion 13, for example, the height of a part in the long side direction Y may be different from that of other parts. For example, the corrugated plate portion 13 in the central portion Am may protrude compared to the corrugated plate portion 13 in the pair of end portions Ae. Although heat tends to accumulate and become high temperature near the center in the long side direction Y, by protruding the corrugated plate portion 13 in the central portion Am, a cooling medium (for example, air) can easily flow into the space S in the central portion Am, and the heat in the central portion Am can be efficiently released.

[0038] FIG. 5 is a plan view schematically showing the power storage device 100. As shown in FIG. 5, in the present embodiment, a pair of long side walls 12b each have a corrugated plate portion 13. More specifically, a pair of long side walls 12b are each composed of a corrugated plate portion 13. In this case, it is preferable that the pair of long side walls 12b are provided in a symmetric shape. More specifically, in a plan view, it is preferable that they are provided in line symmetry with the center line in the short side direction X of the battery case 10 as the axis of symmetry. Thereby, the electrode body 20 in the battery case 10 is easily pressed evenly from the arrangement direction X. However, in other embodiments, the pair of long side walls 12b may be provided asymmetrically.

[0039] As shown in FIG. 3, the sealing plate 14 is attached to the case body 12 so as to close the opening 12h of the case body 12. The sealing plate 14 faces the bottom wall 12a of the case body 12. The sealing plate 14 is substantially rectangular in a plan view. The battery case 10 is integrated by joining (preferably by welding) the sealing plate 14 to the peripheral edge of the opening 12h of the case body 12. The battery case 10 is hermetically sealed.

[0040] The sealing plate 14 is provided with a discharge valve 17 and two terminal lead-out holes 18 and 19. The discharge valve 17 is configured to break when the pressure in the battery case 10 becomes a predetermined value or more and discharge the gas in the battery case 10 to the outside. The terminal lead-out holes 18 and 19 penetrate the sealing plate 14 in the vertical direction Z.

[0041] The positive electrode terminal 30 is electrically connected to the positive electrode tab group 23 of the electrode body 20 via the positive electrode current collector portion 50 inside the battery case 10. The positive electrode terminal 30 extends from the inside to the outside of the sealing plate 14 through the terminal lead-out hole 18. The positive electrode terminal 30 is arranged at one end (the left end in FIGS. 2 and 3) in the long side direction Y of the sealing plate 14. Here, the positive electrode terminal 30 is caulked to the peripheral portion surrounding the terminal lead-out hole 18 of the sealing plate 14 by caulking. The positive electrode terminal 30 is fixed to the sealing plate 14.

[0042] The negative terminal 40 is electrically connected to the negative tab group 25 of the electrode body 20 via the negative current collector 60 inside the battery case 10. The negative terminal 40 extends from the inside to the outside through the terminal lead-out hole 19 and the sealing plate 14. The negative terminal 40 is arranged at the other end (the right end in FIGS. 2 and 3) in the long side direction Y of the sealing plate 14. Here, the negative terminal 40 is caulked to the peripheral portion surrounding the terminal lead-out hole 19 of the sealing plate 14 by caulking. The negative terminal 40 is fixed to the sealing plate 14.

[0043] The power storage module 500 as described above is typically housed in a housing. The housing is provided with an inlet through which air, which is a cooling medium, flows in, for example, below one side in the arrangement direction X of the power storage module 500, and an outlet for air is provided, for example, above the other side in the arrangement direction X. It is preferable that an air-cooling fan is attached to the inlet. The air-cooling fan includes, for example, an electric motor electrically connected to a control device, and is configured to send wind (air) as a cooling medium to the inlet. When the air-cooling fan is driven by the control device, air flows into the housing from the inlet. The air flowing into the housing passes through the inside of the power storage module 500 while flowing through the space S and cooling the plurality of power storage devices 100, and is discharged from the outlet. According to such an air-cooled cooling system, the power storage device 100 can be cooled at low cost.

[0044] The power storage module 500 can be used for various applications. Since it has high heat dissipation and can also be reduced in weight, it can be suitably used, for example, as a power source (driving power source) for a motor mounted on a vehicle such as a passenger car or a truck. The type of vehicle is not particularly limited, and examples include a plug-in hybrid electric vehicle (PHEV), a hybrid electric vehicle (HEV), and a battery electric vehicle (BEV).

[0045] The preferred embodiments of the present invention have been described above, but the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the content disclosed in this specification and the common general knowledge in the art. The technology described in the claims includes various modifications and changes of the above-exemplified embodiments. For example, it is also possible to replace a part of the above-described embodiments with other modified examples, and it is also possible to add other modified examples to the above-described embodiments. Further, if the technical features are not described as essential, they can be appropriately deleted.

[0046] For example, in the embodiment of FIG. 5 described above, the pair of long side walls 12b each had a corrugated plate portion 13. However, it is not limited to this. FIG. 6 is a diagram corresponding to FIG. 5 according to the first modified example. As shown in FIG. 6, in the first modified example, among the pair of long side walls 12b, only the first long side wall 12b has a corrugated plate portion 13. The second long side wall 12b does not have a corrugated plate portion 13. The second long side wall 12b is flat, and both the inner surface and the outer surface are flat. In this case, when constructing the power storage module 500, it is preferable to combine the first long side wall 12b of the first power storage device 100 and the second long side wall 12b of the second power storage device 100 so as to face each other. Thereby, a plurality of power storage devices 100 can be held more stably, and it becomes easier to secure a wide space S.

[0047] For example, in the embodiment of FIG. 2 described above, the positive electrode terminal 30 and the negative electrode terminal 40 were attached to a single sealing plate 14 (the same surface of the battery case 10). However, it is not limited to this. FIG. 7 is a diagram corresponding to FIG. 2 according to the second modification. As shown in FIG. 7, in the second modification, the power storage device 200 includes a battery case 110. The battery case 110 includes, here, a rectangular tube-shaped case body 112 having a pair of openings at both ends in the long side direction Y, and two sealing plates 114 that close the pair of openings of the case body 112. The case body 112 is formed, for example, by bending a single metal plate into a tubular shape and joining (for example, welding) the seams. Here, the welded joint 112d is located on the upper surface of the case body 112. The battery case 110 is integrated by joining the sealing plates 114 to the peripheries of the pair of openings of the case body 112, respectively.

[0048] Similar to the embodiment of FIG. 2, the case body 112 has a pair of long side walls 112b formed of corrugated plate portions 113. The positive electrode terminal 130 and the negative electrode terminal 140 are respectively fixed to two sealing plates 114 (opposing surfaces of the battery case 110) here. Specifically, the positive electrode terminal 130 is attached to the sealing plate 114 disposed on one side in the long side direction Y (the right end portion in FIG. 7). The negative electrode terminal 140 is attached to the sealing plate 114 disposed on the other side in the long side direction Y (the left end portion in FIG. 7). Also in such a power storage device 200, the technology disclosed here can be preferably applied.

[0049] As described above, specific aspects of the technology disclosed here include those described in the following items. Item 1: A power storage device including a battery case having a pair of side walls and an electrode body housed in the battery case, wherein the battery case has a corrugated plate portion formed in a corrugated shape with uneven cross-section on at least one of the pair of side walls. Item 2: The power storage device according to Item 1, wherein the corrugated plate portion is provided so as to face the entire electrode body when viewed from the side wall side. Item 3: The power storage device according to item 1 or item 2, wherein the side wall has a rectangular shape having a long side and a short side, and when the side wall is divided into three equal parts in the long side direction into a pair of end portions and a central portion, the corrugated plate portion is provided across the pair of end portions and the central portion. Item 4: The power storage device according to any one of items 1 to 3, wherein the side wall has a rectangular shape having a long side and a short side, and the unevenness is arranged along the long side. Item 5: The power storage device according to any one of items 1 to 4, wherein the side wall is made of an iron alloy. Item 6: The power storage device according to any one of items 1 to 5, wherein each of the pair of side walls has the corrugated plate portion. Item 7: The power storage device according to item 6, wherein the pair of side walls are provided in a symmetrical shape. Item 8: A power storage module in which a plurality of power storage devices according to any one of claims 1 to 7 are combined such that the side walls face each other. Item 9: The power storage device according to any one of items 1 to 5, wherein among the pair of side walls, the first side wall has the corrugated plate portion, and the second side wall does not have the corrugated plate portion and is formed in a flat plate shape. Item 10: A power storage module including a plurality of the power storage devices according to item 9, combined such that the first side wall of the first power storage device faces the second side wall of the second power storage device.

Explanation of Reference Numerals

[0050] 10, 110 Battery case 12, 112 Case body 12b, 112b Long side wall 13, 113 Corrugated plate portion 14, 114 Sealing plate 20 Electrode body 100, 200 Power storage device 300 Restraint mechanism 500 Power storage module

Claims

1. A battery case having a pair of side walls, and an electrode body housed in the battery case, comprising: The battery case has a corrugated plate portion formed in a corrugated shape with uneven cross-section on at least one of the pair of side walls, a power storage device.

2. The corrugated plate portion is provided so as to face the entire electrode body when viewed from the side wall side, The power storage device according to claim 1.

3. The side wall is rectangular having a long side and a short side, When the side wall is divided into three equal parts in the long side direction into a pair of end portions and a central portion, The corrugated plate portion is provided across the pair of end portions and the central portion, The power storage device according to claim 1.

4. The side wall is rectangular having a long side and a short side, The unevenness is arranged along the long side, The power storage device according to any one of claims 1 to 3.

5. The side wall is made of an iron alloy, The power storage device according to any one of claims 1 to 3.

6. Each of the pair of side walls has the corrugated plate portion, The power storage device according to any one of claims 1 to 3.

7. The pair of side walls are provided in a symmetrical shape, The power storage device according to claim 6.

8. A power storage module in which a plurality of the power storage devices according to any one of claims 1 to 3 are combined such that the side walls face each other.

9. Among the pair of side walls, The first side wall has the corrugated plate portion, The second side wall does not have the corrugated plate portion and is formed in a flat plate shape, The power storage device according to any one of claims 1 to 3.

10. A plurality of the power storage devices according to claim 9 are provided, A power storage module in which the first side wall of the first power storage device and the second side wall of the second power storage device are combined so as to face each other.

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