Power storage device

Abstract

The power storage device (1) is equipped with: a power storage stack (10) including a first battery group (11), a second battery group (12) and an intermediate plate (13); a lower case (21) having a bottom wall portion (22); a first heat conduction member (61) arranged between the first battery group (11) and the bottom wall portion (22); and a second heat conduction member (62) arranged between the second battery group (12) and the bottom wall portion (22), wherein the lower case (21) includes a base portion (25) supporting the intermediate plate (13), and the first heat conduction member (61) and the second heat conduction member (62) are arranged to contact the base portion (25).

Description

Technical Field

[0001] The present disclosure relates to a power storage device mounted on a vehicle. Background Art

[0002] As a previous power storage device, Japanese Patent Gazette No. 2020-053148 discloses a power storage device, in which a power storage stack and a cooler are arranged in a housing, and is equipped with a cooler and a power storage stack. The cooler is provided with multiple main cooling surfaces and recessed portions located between the multiple main cooling surfaces, and a gel-like heat conduction member is arranged between the multiple main cooling surfaces and the power storage stack. Summary of the Invention

[0003] However, in the power storage device described in Japanese Patent Application Laid-Open No. 2020-053148, since recessed portions are provided between the plurality of main cooling surfaces, it is difficult to ensure a large area of the heat conduction member, and there is a risk of reduced thermal conductivity.

[0004] Furthermore, studies have been conducted on structures in which the cooler is located outside the housing. In this case, a heat-conducting member is used to thermally seal the bottom surface of the battery stack to the bottom wall of the lower housing. When the bottom surface of the battery stack and the bottom wall are bonded together via the heat-conducting member, air may remain between the bottom surface of the battery stack and the bottom wall, preventing it from escaping. In this case, the seal between the battery stack and the lower housing is reduced. Furthermore, if the area of the heat-conducting member is small, thermal conductivity is reduced.

[0005] The present disclosure has been made in view of the above-mentioned problems, and an object of the present disclosure is to provide an electricity storage device that can improve the close contact of an electricity storage stack with respect to a lower case via a heat conduction member and can ensure good heat conduction.

[0006] The power storage device disclosed herein includes: a power storage stack including a first battery group and a second battery group each containing a plurality of power storage batteries, and an intermediate plate disposed between the first and second battery groups; a lower housing having a bottom wall portion, in which the power storage stack is disposed; a first heat conduction member disposed between the first battery group and the bottom wall portion; and a second heat conduction member disposed between the second battery group and the bottom wall portion. The lower housing includes a base portion that rises from the bottom wall portion and supports the intermediate plate. The first and second heat conduction members are disposed in contact with the base portion.

[0007] In the above-described structure, the intermediate plate is supported by the base, and the first and second heat-conducting members are pressed and expanded by the battery stack and the bottom wall of the lower case, bringing the first and second heat-conducting members into contact with the base. This allows air to escape from the periphery of the base, which is surrounded by the first and second heat-conducting members, the bottom surface of the battery stack, and the bottom wall, while also pressing and expanding the first and second heat-conducting members. This ensures a large surface area for the first and second heat-conducting members. Consequently, the close contact between the battery stack (first and second battery packs) and the bottom wall of the lower case via the first and second heat-conducting members is enhanced, ensuring excellent thermal conductivity.

[0008] In the power storage device according to the present disclosure, the intermediate plate may include a first protrusion protruding from the base portion toward the first battery pack, and a second protrusion protruding from the base portion toward the second battery pack, in the arrangement direction of the first and second battery packs. In this case, when viewed from a direction perpendicular to the arrangement direction, the first heat conduction member may be provided so as to fill the space between the first protrusion and the base portion, and the second heat conduction member may be provided so as to fill the space between the second protrusion and the base portion.

[0009] According to the above configuration, the first heat conduction member and the second heat conduction member can be reliably brought into contact with each other up to the end of the first battery pack and the end of the second battery pack located on the middle plate side.

[0010] In the power storage device according to the present disclosure, the base portion may include a first base portion and a second base portion that are arranged apart from each other in a direction perpendicular to an arrangement direction of the first battery pack and the second battery pack.

[0011] According to the above configuration, when the first and second heat conduction members are pressed and expanded, air can escape from around both the first and second base portions, thereby further improving the adhesion between the battery stack and the lower case.

[0012] The power storage device disclosed herein may also be equipped with a cooler for cooling the power storage stack. The bottom wall portion may also have an inner main surface facing the power storage stack and an outer main surface located opposite the power storage stack. In this case, the cooler is preferably positioned on the outer side of the lower housing so as to be in thermal contact with the outer main surface.

[0013] With the above configuration, in a structure in which the cooler is arranged outside the lower case, the battery stack can be cooled via the bottom wall portion of the lower case, and the first and second heat conduction members.

[0014] The battery storage device disclosed herein may further include a pressing member for pressing the battery stack toward the bottom wall. The battery stack has one end and another end in the arrangement direction. In this case, the pressing member preferably includes a first pressing portion for pressing the one end toward the bottom wall, and a second pressing portion for pressing the other end toward the bottom wall.

[0015] With the above-described structure, the battery stack can be pressed toward the bottom wall, thereby further improving the close contact between the battery stack and the bottom wall of the lower case.

[0016] The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when read with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is an exploded perspective view of the power storage device according to the embodiment.

[0018] Figure 2 is a cross-sectional view of a power storage device according to an embodiment.

[0019] Figure 3 This is a partial cross-sectional view showing an enlarged view of the lower end and the surroundings of the intermediate plate of the power storage device according to the embodiment.

[0020] Figure 4 This is a schematic diagram showing an initial state of the step of attaching the electricity storage stack to the lower case via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment.

[0021] Figure 5 This is a plan view of the first heat conduction member and the second heat conduction member applied to the bottom wall portion.

[0022] Figure 6 This is a schematic diagram showing a state in the middle of the step of attaching the electricity storage stack to the lower case via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment.

[0023] Figure 7 It is schematically indicated in Figure 6 The diagram shows the movement of air between the bottom surface and the bottom wall of the battery stack in the intermediate state shown.

[0024] Figure 8This is a schematic diagram showing a state subsequent to the step of attaching the electricity storage stack to the lower case via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In the embodiments shown below, identical or common parts are denoted by identical reference numerals, and description thereof will not be repeated.

[0026] Figure 1 It is an exploded perspective view of the power storage device according to the embodiment. Figure 2 is a cross-sectional view of the power storage device according to the embodiment, taken along Figure 1 The cross-sectional view of the II-II line is shown. Figure 2 For the sake of convenience, the illustration of the common plate 50 to be described later is omitted. Figure 1 and Figure 2 , a power storage device 1 according to an embodiment will be described.

[0027] The power storage device 1 according to the embodiment is mounted on a hybrid vehicle that can run using power from at least one of an electric motor and an engine, or an electric vehicle that runs using driving force obtained by a motor generator.

[0028] like Figure 1 as well as Figure 2 As shown, the power storage device 1 according to the embodiment includes a plurality of power storage stacks 10, a housing case 20, a cooler 30, an outer heat conduction layer 40, a common plate 50, a heat conduction member 60, and a pressing member 80 (see Figure 2 ).

[0029] Each of the plurality of storage battery stacks 10 includes a first battery group 11, a second battery group 12, an intermediate plate 13, and a pair of end plates 16 (see Figure 2 ).

[0030] The first battery pack 11 and the second battery pack 12 include a plurality of storage batteries 15 (see FIG. 1 ) arranged in parallel in a predetermined direction (DR1 direction). Figure 2 When the power storage device 1 is mounted on the vehicle, the DR1 direction is, for example, parallel to the width direction of the vehicle.

[0031] Battery 15 is a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. The secondary battery has, for example, a rectangular shape. The secondary battery may use a liquid electrolyte or a solid electrolyte. Alternatively, battery 15 may be a unit capacitor configured to store electricity.

[0032] The intermediate plate 13 is disposed between the first battery pack 11 and the second battery pack 12. The intermediate plate 13 is disposed at the center of the battery stack 10 in the direction DR1. The intermediate plate 13 is made of, for example, an insulating synthetic resin.

[0033] The arrangement direction of the first battery group 11 and the second battery group 12 is parallel to the direction in which the plurality of storage batteries 15 are arranged in parallel, and is parallel to the DR1 direction.

[0034] The pair of end plates 16 are disposed at both ends of the electricity storage stack 10 in the DR1 direction, sandwiching the first cell group 11, the intermediate plate 13, and the second cell group 12. The pair of end plates 16 are made of a metal material such as aluminum.

[0035] The plurality of power storage stacks 10 are arranged in parallel in a direction (DR2 direction) perpendicular to the DR1 direction. When the power storage device 1 is mounted on a vehicle, the DR2 direction is, for example, parallel to the front-rear direction of the vehicle.

[0036] The housing case 20 houses the plurality of battery stacks 10 therein. The housing case 20 includes a lower case 21 and an upper case 26 .

[0037] The lower case 21 has a generally box-like shape that is open upward. The lower case 21 has thermal conductivity and is formed of, for example, metal. The lower case 21 includes a bottom wall 22, a peripheral wall 23, a flange 24, a base 25, a partition wall 211, and a reinforcement bracket 212 (see FIG. Figure 2 ).

[0038] Bottom wall portion 22 is located below multiple battery stacks 10. Bottom wall portion 22 has an inner main surface 22a facing battery stack 10 and an outer main surface 22b facing the side opposite to the battery stack 10.

[0039] The peripheral wall portion 23 is provided so as to stand upright from the peripheral edge of the bottom wall portion 22. The flange portion 24 is provided so as to protrude outward from the upper end of the peripheral wall portion 23.

[0040] A plurality of partition walls 211 are provided. The partition walls 211 are arranged in parallel in the DR2 direction at predetermined intervals. The partition walls 211 separate the areas where the battery stacks 10 are arranged at predetermined intervals. In this embodiment, the partition walls 211 separate the areas where the two battery stacks 10 are arranged, but this is not limiting, and the positions of the partition walls 211 can be appropriately set. The partition walls 211 are connected to the peripheral wall portion 23 at both ends in the DR1 direction. The partition walls 211 reinforce the peripheral wall portion 23.

[0041] The base portion 25 is provided so as to bulge upward from the center portion of the bottom wall portion 22 in the DR1 direction. A plurality of base portions 25 are provided corresponding to each battery stack 10. The base portion 25 is provided in each area partitioned by the plurality of partition walls 211. The top portion 251 of the base portion 25 (see Figure 3 The intermediate plate 13 is placed on the top portion 251 of the base portion 25. The base portion 25 supports the intermediate plate 13.

[0042] The base portion 25 includes a first base portion 255 and a second base portion 256. The first base portion 255 and the second base portion 256 are spaced apart from each other in the DR2 direction. The first base portion 255 supports one end of the intermediate plate 13 in the DR2 direction. The second base portion 256 supports the other end of the intermediate plate 13 in the DR2 direction.

[0043] Reinforcement brackets 212 are disposed between peripheral wall portion 23 and electricity storage stack 10 on both sides of electricity storage stack 10 in direction DR1. Reinforcement brackets 212 reinforce the attachment of electricity storage stack 10 to bottom wall portion 22.

[0044] Reinforcement bracket 212 has an upper end, a lower end, and a connecting portion connecting the upper and lower ends. The upper and lower ends are flat plate-shaped and extend in the DR1 direction away from battery stack 10. The connecting portion is provided to extend in the vertical direction.

[0045] The lower end portion of the reinforcing bracket 212 is connected to the inner main surface 22a of the bottom wall portion 22 by welding or the like. The upper end portion of the reinforcing bracket 212 is connected to the flange portion 24 by welding or the like.

[0046] The upper case 26 has a substantially box-like shape that is open downward. The upper case 26 is made of metal, for example.

[0047] The upper case 26 includes a top plate 27, a peripheral wall 28, and a flange 29. The top plate 27 forms the upper wall of the housing case 20. The peripheral wall 28 extends downward from the periphery of the top plate 27. The flange 29 extends outward from the lower end of the peripheral wall 28.

[0048] The flange portions 24 and 29 are fastened together by a plurality of fastening members (not shown) while being vertically overlapped. As a result, the upper case 26 and the lower case 21 house the plurality of electricity storage stacks 10 therein.

[0049] The cooler 30 is a device for cooling the multiple battery stacks 10. The cooler 30 is located outside the housing 20. Specifically, the cooler 30 is located below the bottom wall 22 of the lower housing 21. An outer heat conduction layer 40 is located between the cooler 30 and the outer main surface 22b. The cooler 30 is located outside the lower housing 21 in thermal contact with the outer main surface 22b.

[0050] The cooler 30 is made of a metal material such as aluminum. The cooler 30 includes a plurality of main cooling units 31 and a holding unit 32. A refrigerant flow path 31a is provided inside the plurality of main cooling units 31 and the holding unit 32. A refrigerant for cooling the battery stack 10 flows through the refrigerant flow path 31a (see Figure 2 In the main cooling section 31, the refrigerant is Figure 2 As indicated by the middle arrow, the water flows from the first battery group 11 side to the second battery group 12 side.

[0051] The cooler 30 includes a refrigerant inlet 33 and a refrigerant discharge 34. Refrigerant is introduced from the outside into the refrigerant flow path via the refrigerant inlet 33. Refrigerant is discharged from the refrigerant flow path via the refrigerant discharge 34.

[0052] The plurality of main cooling units 31 are arranged in parallel in a direction parallel to the DR2 direction. The plurality of main cooling units 31 extend along the DR1 direction. The plurality of main cooling units 31 are each arranged at a position facing the battery stack 10 with the bottom wall 22 interposed therebetween.

[0053] The retaining portion 32 retains the plurality of primary cooling units 31. The retaining portion 32 is configured to retain at least both ends of the primary cooling units 31 in the DR1 direction. For example, the retaining portion 32 may include a pair of extensions extending along the DR2 direction at both ends of the primary cooling units 31. Alternatively, the retaining portion 32 may be configured in a frame shape to surround the plurality of primary cooling units 31.

[0054] The outer heat conducting layer 40 is made of a heat conducting material and is disposed between the bottom wall portion 22 of the lower case 21 and the cooler 30. The outer heat conducting layer 40 includes a plurality of central heat conducting portions 41 and an annular heat conducting portion 42.

[0055] The plurality of central heat conducting portions 41 are disposed between the main cooling portions 31 and the bottom wall portion 22 of the lower case 21. The central heat conducting portion 41 has a shape extending in the DR1 direction.

[0056] The annular heat conducting portion 42 has a shape surrounding each central heat conducting portion 41. The annular heat conducting portion 42 is disposed between the holding portion 32 and the housing case 20. This prevents water from entering the space inside the annular heat conducting portion 42.

[0057] The outer heat-conducting layer 40 also functions as an adhesive layer to bond and fix the cooler 30 to the bottom wall portion 22. The outer heat-conducting layer 40 is made of an adhesive containing silicone resin, acrylic resin, urethane resin, epoxy resin, or the like.

[0058] The common plate 50 is arranged so as to cover the cooler 30 from below. The common plate 50 protects the cooler 30 and prevents water from entering the cooler 30. The common plate 50 is made of a metal material.

[0059] The heat conduction member 60 is disposed between each of the battery stacks 10 and the bottom wall 22 (more specifically, the inner main surface 22 a ). The heat conduction member 60 also functions as an adhesive layer, bonding and fixing each of the battery stacks 10 to the bottom wall 22 .

[0060] The heat conduction member 60 includes a first heat conduction member 61 and a second heat conduction member 62. The first heat conduction member 61 is disposed between the first battery pack 11 and the bottom wall 22. The first heat conduction member 61 adhesively secures the first battery pack 11 to the bottom wall 22. The second heat conduction member 62 is disposed between the second battery pack 12 and the bottom wall 22. The second heat conduction member 62 adhesively secures the second battery pack 12 to the bottom wall 22.

[0061] The first heat conduction member 61 and the second heat conduction member 62 are made of a resin material having thermal conductivity. For example, an adhesive containing silicone resin, acrylic resin, urethane resin, or epoxy resin can be used as the first heat conduction member 61 and the second heat conduction member 62. When the first heat conduction member 61 and the second heat conduction member 62 are made of the same material, the components can be simplified compared to when they are made of different materials.

[0062] Furthermore, the refrigerant flows from the first battery pack 11 to the second battery pack 12. That is, the refrigerant that has cooled the first battery pack 11 cools the second battery pack 12. Therefore, to minimize the temperature difference between the first and second battery packs 11, the thermal conductivity of the second heat conduction member 62 may be higher than that of the first heat conduction member 61.

[0063] The pressing member 80 presses the battery stack 10 toward the bottom wall 22. The pressing member 80 presses the battery stack 10 toward the bottom wall 22, thereby pressing and expanding the first and second heat conduction members 61 and 62, thereby attaching the battery stack 10 to the housing case 20. The pressing member 80 includes a first pressing portion 81 and a second pressing portion 82.

[0064] The first pressing portion 81 presses one end of the battery stack 10 in the DR1 direction toward the bottom wall 22 . The first pressing portion 81 includes a bracket 811 , an inner fastening member 812 , and an outer fastening member 813 .

[0065] The bracket 811 is a member used to attach the first battery pack 11 to the housing case 20. The bracket 811 is made of metal. Its inner end in the DR1 direction is secured to one end of the battery stack 10 by an inner fastening member 812. Its outer end in the DR1 direction is secured to the upper end of the reinforcement bracket 212 by an outer fastening member 813.

[0066] The second pressing portion 82 presses the other end of the battery stack 10 in the DR1 direction toward the bottom wall 22 . The second pressing portion 82 includes a bracket 821 , an inner fastening member 822 , and an outer fastening member 823 .

[0067] Bracket 821 is a member used to attach the second battery pack 12 to the housing case 20. Bracket 821 is made of metal. Its inner end in the DR1 direction is secured to the other end of the battery stack 10 by an inner fastening member 822. Its outer end in the DR1 direction is secured to the upper end of the reinforcement bracket 212 by an outer fastening member 823.

[0068] As described above, the first and second pressing portions 81 and 82 press the first and second battery packs 11 and 12 toward the bottom wall 22 , thereby pressing and expanding the first heat conduction member 61 disposed between the first and second battery packs 11 and the bottom wall 22 , and the second heat conduction member 62 disposed between the second and second battery packs 12 and the bottom wall 22 .

[0069] Figure 3 FIG. 1 is a partial cross-sectional view showing an enlarged view of the lower end and the vicinity of the intermediate plate of the power storage device according to the embodiment. Figure 3 For the sake of convenience, the outer heat conducting layer 40, the cooler 30, and the common plate 50 are omitted. Figure 3 , the structure around the lower end of the intermediate plate 13 will be described.

[0070] like Figure 3 As shown, the base portion 25 includes a top portion 251 and inclined portions 252 and 253. The top portion 251 has a generally flat plate shape. The inclined portion 252 is connected to one end of the top portion 251 in the DR1 direction and slopes downward as it approaches one side in the DR1 direction (one end of the battery stack 10). The inclined portion 253 is connected to the other end of the top portion in the DR1 direction and slopes downward as it approaches the other side in the DR1 direction (the other end of the battery stack 10).

[0071] The intermediate plate 13 is placed on the base portion 25 (more specifically, the top portion 251 ) and has a first end portion 13 a located on the first battery group 11 side and a second end portion 13 b located on the second battery group 12 side in the DR1 direction.

[0072] The intermediate plate 13 includes a first protrusion 131 protruding from the top 251 of the base portion 25 toward the first battery pack 11 , and a second protrusion 132 protruding from the top 251 of the base portion 25 toward the second battery pack 12 .

[0073] The first heat conduction member 61 is provided so as to be in contact with the base portion 25. An end portion 61a of the first heat conduction member 61, which is located on the second heat conduction member 62 side, is in contact with the inclined portion 252. When viewed from a direction perpendicular to the arrangement direction, the first heat conduction member 61 is provided so as to fill the space between the first protrusion 131 and the base portion 25.

[0074] The second heat conduction member 62 is provided so as to be in contact with the base portion 25. An end portion 62a of the second heat conduction member 62 located on the first heat conduction member 61 side is in contact with the inclined portion 253. When viewed from a direction perpendicular to the arrangement direction, the second heat conduction member 62 is provided so as to fill the space between the second protrusion 132 and the base portion 25.

[0075] Figure 4 This is a schematic diagram showing an initial state of the step of attaching the electricity storage stack 10 to the lower case 21 via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment.

[0076] like Figure 4 As shown, when the battery stack 10 is mounted on the lower case 21 via the first heat conduction member 61 and the second heat conduction member 62 , first, with the bottom wall 22 of the lower case 21 coated with the first heat conduction member 61 and the second heat conduction member 62 , the bottom wall 22 is positioned facing the battery stack 10 .

[0077] Figure 5 This is a plan view of the first heat conduction member and the second heat conduction member applied to the bottom wall portion.

[0078] like Figure 5 As shown, the first heat conduction member 61 and the second heat conduction member 62 are applied to the inner main surface 22a of the bottom wall portion 22. The first heat conduction member 61 and the second heat conduction member 62 are applied in a substantially C-shape that opens toward the base portion 25. The first heat conduction member 61 and the second heat conduction member 62 may be applied continuously or intermittently at intervals. The first heat conduction member 61 and the second heat conduction member 62 are applied so as to form a gap between them and the base portion 25.

[0079] The first heat conducting member 61 is coated to include a first portion 611, a second portion 612, and a third portion 613. The first portion 611 and the second portion 612 are formed with a gap in the DR2 direction and extend in the DR1 direction. The third portion 613 is provided at the end of the first portion 611 and the second portion 612, located on the side opposite to the base portion 25 in the DR1 direction. The third portion 613 is provided to extend in the DR2 direction.

[0080] Similarly, the second heat conducting member 62 is coated to include a first portion 621, a second portion 622, and a third portion 623. The first portion 621 and the second portion 622 are formed with a gap in the DR2 direction and extend in the DR1 direction. The third portion 623 is provided at the end of the first portion 621 and the second portion 622 on the side opposite to the base portion 25 in the DR1 direction. The third portion 623 is provided to extend in the DR2 direction.

[0081] Figure 6 This is a schematic diagram showing a state in the middle of the step of attaching the electricity storage stack 10 to the lower case 21 via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment.

[0082] like Figure 6 As shown, in the intermediate state, the battery stack 10 is moved toward the bottom wall 22 to narrow the gap between the bottom surface of the battery stack 10 and the bottom wall 22. At this time, the first and second heat conduction members 61 and 62 are sandwiched between the first and second battery packs 11 and 12 and the bottom wall 22, and are pressed and expanded.

[0083] Figure 7 It is schematically indicated in Figure 6 The diagram shows the movement of air between the bottom surface and the bottom wall of the battery stack in the intermediate state shown.

[0084] like Figure 7 As shown, when the first heat conduction member 61 and the second heat conduction member 62 are pressed and expanded, as indicated by the arrows in the figure, air in the spaces S1 and S2 surrounded by the first heat conduction member 61, the second heat conduction member 62, the bottom surface of the battery stack 10, and the bottom wall 22 can escape from around the base 25 to the outside of the battery stack 10. The pressed and expanded first heat conduction member 61 and the second heat conduction member 62 fill the space between the first and second battery packs 11 and 12 and the bottom wall 22.

[0085] In this way, by allowing air to escape and by pressing and expanding the first and second heat conduction members 61 and 62, the close contact between the battery stack 10 and the bottom wall 22 of the lower case 21 can be improved. Furthermore, by allowing air to escape from around both the first and second base portions 255 and 256, the close contact can be further improved.

[0086] Figure 8 This is a schematic diagram showing a state subsequent to the step of attaching the electricity storage stack 10 to the lower case 21 via the first heat conduction member and the second heat conduction member in the manufacturing process of the electricity storage device according to the embodiment.

[0087] like Figure 8 As shown, in the subsequent state, the intermediate plate 13 is placed on the base portion 25, and the first heat conduction member 61 and the second heat conduction member 62 are in contact with the base portion 25. Thus, by pressing and expanding the first heat conduction member 61 and the second heat conduction member 62, a large area can be ensured. This ensures good thermal conductivity.

[0088] At this time, as described above, the first heat conduction member 61 is filled between the first protrusion 131 and the base portion 25, and the second heat conduction member 62 is filled between the second protrusion 132 and the base portion 25, extending to the ends of the first battery pack 11 and the second battery pack 12 located on the side of the middle plate 13. This ensures that the first heat conduction member 61 and the second heat conduction member 62 are in contact with each other.

[0089] Furthermore, by using the pressing member 80 , the first cell group 11 and the second cell group 12 can be pressed more firmly against the bottom wall portion 22 , thereby further improving the adhesion of the electricity storage stack 10 .

[0090] In the above description, the example of the pressing member 80 being fixed to the reinforcing bracket 212 is used for explanation. However, the present invention is not limited to this, and the pressing member 80 may also be fixed to the bottom wall 22. Furthermore, if the heat conduction member 60 can adequately secure the battery stack 10 to the bottom wall 22, the pressing member 80 and the reinforcing bracket 212 may be omitted.

[0091] While the embodiments of the present invention have been described above, the embodiments disclosed herein are illustrative in all respects and should not be construed as restrictive. The scope of the present invention is indicated by the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims.

Claims

1. An electric storage device comprising: A battery stack including a first battery group and a second battery group each including a plurality of batteries, and an intermediate plate disposed between the first battery group and the second battery group; a lower case having a bottom wall portion, wherein the battery stack is disposed on the lower case; a first heat conducting member disposed between the first battery pack and the bottom wall; as well as a second heat conducting member disposed between the second battery pack and the bottom wall; The lower housing includes a base portion, which is arranged to bulge from the bottom wall portion and supports the intermediate plate. The first heat conduction member and the second heat conduction member are provided in contact with the base portion.

2. The power storage device according to claim 1, wherein The intermediate plate has a first protrusion protruding from the base toward the first battery pack and a second protrusion protruding from the base toward the second battery pack in the arrangement direction of the first battery pack and the second battery pack. When viewed from a direction perpendicular to the arrangement direction, the first heat conduction member is provided so as to fill a space between the first protrusion and the base portion, and the second heat conduction member is provided so as to fill a space between the second protrusion and the base portion.

3. The power storage device according to claim 1 or 2, wherein The base portion includes a first base portion and a second base portion that are arranged to be separated from each other in a direction orthogonal to an arrangement direction in which the first battery pack and the second battery pack are arranged.

4. The power storage device according to any one of claims 1 to 3, wherein A cooler is also provided for cooling the battery stack. The bottom wall portion has an inner main surface facing the battery stack and an outer main surface facing a side opposite to the battery stack. The cooler is arranged outside the lower case so as to be in thermal contact with the outer main surface.

5. The power storage device according to any one of claims 1 to 4, wherein A pressing member for pressing the battery stack toward the bottom wall is also provided. The battery stack has one end and another end in the direction in which the first battery group and the second battery group are arranged. The urging member includes a first urging portion for urging the one end toward the bottom wall portion, and a second urging portion for urging the other end toward the bottom wall portion.

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