Power supply system

Abstract

The present invention is provided with: a plurality of battery cells each having an end surface; an exterior case in which a plurality of battery cells are housed and the lower surface of which is a thermally conductive bottom plate that thermally couples with the end surfaces of the plurality of battery cells; and a cooling plate that thermally couples with a second surface of the bottom plate on the opposite side to the first surface thereof which is thermally coupled to the end surfaces of the plurality of battery cells.

Description

Power System

[0001] The present disclosure relates to power supply systems.

[0002] Power supply devices (power supply systems) are used in which a large number of rechargeable secondary battery cells, such as lithium-ion secondary batteries, are connected in series or parallel to drive electrical equipment, electric vehicles such as vehicles and construction machinery, or for stationary power storage or backup applications (see, for example, Patent Document 1). The secondary battery cells used in such power supply devices generate heat during charging and discharging and therefore need to be cooled. To efficiently cool a large number of secondary battery cells, a cooling plate is thermally coupled to the bottom surface of each secondary battery cell. In such a cooling system using a cooling plate, efficient thermal conduction between the bottom surface of the secondary battery cells and the cooling plate is required.

[0003] In this type of cooling system using a cooling plate, it is conceivable to interpose a bottom plate between the bottom surface of the secondary battery cell and the cooling plate, and dissipate heat by thermal conduction through the bottom plate. However, if the bottom surface of the secondary battery cell is covered with a bottom plate, there is a problem in that the rigidity of the part that secures the power supply device is insufficient.

[0004] International Publication No. 2014 / 034079

[0005] One object of one aspect of the present disclosure is to provide a power supply system that can efficiently cool battery cells with a cooling plate. Another object of another aspect is to provide a power supply system that has increased rigidity in a configuration in which battery cells are cooled with a cooling plate. Note that the description of these objects and problems of the present disclosure does not preclude the existence of other objects and problems. Furthermore, it is not necessary for one aspect of the present disclosure to solve all of these problems. Furthermore, problems other than these can be extracted from the description of the specification, drawings, and claims of the present disclosure.

[0006] A power supply system according to one aspect of the present disclosure includes a plurality of battery cells, each having an end face, an exterior case that houses the plurality of battery cells and has a thermally conductive bottom plate whose underside is thermally coupled to the end faces of the plurality of battery cells, and a cooling plate that is thermally coupled to a second surface of the bottom plate opposite to the first surface that is thermally coupled to the end faces of the plurality of battery cells. This configuration has the advantage that the battery cells can be efficiently cooled by the cooling plate.

[0007] In a power supply system according to another aspect of the present disclosure, the exterior case has a fixing portion on one side thereof with a screw hole for fixing to the cooling plate, and the bottom plate has a protrusion that projects from a portion thereof along the end face of the fixing portion. This configuration has the advantage of being able to increase rigidity in a configuration in which the battery cells are cooled by the cooling plate.

[0008] FIG. 1 is a schematic perspective view of a power supply system according to one embodiment of the present invention. FIG. 2 is a schematic exploded perspective view of the power supply system shown in FIG. 1. FIG. 3 is a schematic exploded perspective view of the power supply system shown in FIG. 1, as seen from below. FIG. 4 is a schematic plan view showing an outer case and a fixing portion. FIG. 5 is a schematic plan view showing a bottom plate and a protrusion fixed to the outer case. FIG. 6 is a schematic plan view showing a comparative example. FIG. 7 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 8 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 9 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 10 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 11 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 12 is a schematic plan view showing the protrusion and fixing portion of another example. FIG. 13 is a schematic exploded perspective view of a power supply system according to another embodiment. FIG. 14 is a schematic perspective view of a power supply system according to another embodiment.

[0009] Embodiments of the present invention will be described below with reference to the drawings. However, the embodiments described below are merely illustrative examples for embodying the technical concepts of the present invention, and the present invention does not limit the power supply system to those described below. Furthermore, this specification in no way limits the components described in the claims to those described in the embodiments. The dimensions, materials, shapes, and relative locations of components described in the embodiments are not intended to limit the scope of the present invention, and are merely illustrative examples unless otherwise specified. The size and relative positions of components shown in the drawings may be exaggerated for clarity. Furthermore, in the following description, the same names and symbols indicate identical or similar components, and detailed descriptions will be omitted as appropriate. Furthermore, the elements constituting the present invention may be configured with the same material, so that multiple components are served by a single material. Conversely, the functions of a single material may be shared by multiple materials. In this disclosure, the up-down direction is based on the axial and height directions of the battery cells.

[0010] The present disclosure may be specified by the following configurations and features.

[0011] A power supply system according to one embodiment of the present disclosure includes a plurality of battery cells, each having an end face; an exterior case that houses the plurality of battery cells and has a thermally conductive bottom plate whose underside is thermally coupled to the end faces of the plurality of battery cells; and a cooling plate that is thermally coupled to a second surface of the tom plate opposite to the first surface that is thermally coupled to the end faces of the plurality of battery cells.

[0012] With the above configuration, by interposing the bottom plate with excellent thermal conductivity between the cooling plate and the end face of the battery cell, it is possible to improve the heat dissipation performance of the heat generated by the battery cell.

[0013] In a power supply system according to another embodiment of the present disclosure, the exterior case has a fixing portion on a portion of its side surface that has a screw hole for fixing to the cooling plate, and the bottom plate can have a protrusion that protrudes from a portion of the fixing portion along the edge surface of the fixing portion. This configuration makes it possible to increase the rigidity of the cooling plate fixed to the exterior case. When the bottom plate is shaped to cover only the bottom surfaces of the battery cells, where the battery cells are arranged, the rigidity around the fixing portion of the battery pack is insufficient. In this shape, the bottom plate has a protrusion that protrudes from a portion of the bottom plate that protrudes along the edge surface of the fixing portion, so that the protrusion overlaps the fixing portion, thereby increasing the rigidity of the cooling plate fixed to the exterior case. Furthermore, when the bottom plate has a protrusion that protrudes along the edge surface of the fixing portion, the heat dissipation of heat generated by the battery cells can be improved.

[0014] In another embodiment of the power supply system of the present disclosure, the outer case has a pair of opposing side surfaces on which fixing portions protrude along the screw holes, and the bottom plate has a pair of opposing side surfaces on which protrusions protrude on both sides of the screw holes. With this configuration, the outer case is fixed to the cooling plate by the fixing portions provided on each of the opposing side surfaces, thereby improving the fixing strength and rigidity. Furthermore, with this configuration, the fixing portions protrude from the side surfaces along the screw holes, and the protrusions protrude on both sides of the screw holes, allowing the protrusions to overlap the fixing portions adjacent to both sides of the screw holes, thereby improving the fixing strength and rigidity of the outer case to the cooling plate.

[0015] In another embodiment of the power supply system of the present disclosure, the outer case has a pair of side surfaces intersecting the longitudinal direction, each of which has a fixing portion protruding along the screw hole, and the bottom plate has a protrusion protruding from each of its longitudinal edges on both sides of the screw hole. With this configuration, the outer case has a pair of side surfaces intersecting the longitudinal direction, each of which has a fixing portion, and the bottom plate has a protrusion protruding from each of its longitudinal edges, thereby increasing the fixing strength and rigidity of the outer case to the cooling plate. With this configuration, a portion of the bottom plate can be extended to overlap the portion where the outer case is fixed to the cooling plate, thereby increasing the fixing strength and rigidity of the outer case to the cooling plate. The protrusions can protrude on both sides of the screw hole, overlapping the fixing portions in close proximity to the screw hole.

[0016] In a power supply system according to another embodiment of the present disclosure, the bottom plate may have a protrusion that protrudes flush with the bottom plate. With this configuration, the protrusion protruding flush with the bottom plate not only reduces the cost of the components, but also allows the protrusion and the bottom plate to be in close contact with the fixing part, the outer case, and the cooling plate on the same plane, and the protrusion is sandwiched between the fixing part and the cooling plate, increasing rigidity and thermal conductivity, thereby enabling both rigidity and thermal conductivity to be achieved.

[0017] In a power supply system according to another embodiment of the present disclosure, the protrusion can be fixed to the exterior case by screwing. With the above configuration, the bottom plate is securely and physically fixed to the exterior case, thereby increasing rigidity. With the above configuration, the bottom plate closes the open bottom surface of the exterior case, forming a three-dimensional shape that improves the rigidity of the exterior case. With the above configuration, the protrusion can be fixed to a fixing portion that protrudes from the side by screwing. With the above configuration, the exterior case is further fixed to the cooling plate with a screw inserted into a screw hole in the fixing portion, thereby resolving any lack of rigidity around the fixing portion and ensuring sufficient strength and rigidity to support and hold the mass of multiple battery cells.

[0018] In a power supply system according to another embodiment of the present disclosure, a portion of the protrusion can be sandwiched between the fixing portion and the cooling plate. With the above configuration, the outer case can be fixed to the cooling plate by sandwiching at least a portion of the protrusion between the fixing portion and the cooling plate, thereby increasing rigidity. By using screws inserted into screw holes in the fixing portion protruding from the side of the outer case to sandwich and fix the protrusion extending from a portion of the bottom plate to the cooling plate, the lack of rigidity around the fixing portion can be eliminated, ensuring sufficient strength and rigidity to support and hold the mass of multiple battery cells. Furthermore, thermal conductivity can be increased, achieving both rigidity and thermal conductivity.

[0019] In a power supply system according to another embodiment of the present disclosure, the bottom plate of the exterior case can be formed as a separate member.

[0020] 1 to 5 and 7 to 12 show a power supply system 100 according to a first embodiment of the present disclosure. Fig. 1 is a schematic perspective view of the power supply system 100, Fig. 2 is a schematic exploded perspective view of the power supply system 100, Fig. 3 is a schematic exploded perspective view of the power supply system 100 viewed obliquely from below, Fig. 4 is a schematic plan view showing the outer case 2 and the fixing portion 22, Fig. 5 is a schematic plan view showing the bottom plate 3 and the protrusions 31 fixed to the outer case 2, Fig. 6 is a schematic plan view showing a comparative example, and Figs. 7 to 12 are schematic plan views showing the protrusions 31 and the fixing portion 22 of other examples.

[0021] The power supply system 100 is configured by connecting a large number of rechargeable battery cells, such as lithium-ion secondary batteries, in series or parallel to drive electrical equipment, electric vehicles such as vehicles and construction machinery, or is used for stationary power storage or backup purposes.

[0022] (Power supply system 100) The power supply system 100 shown in Figures 1 to 3 includes a plurality of battery cells 1, each having an end face, an exterior case 2 that houses the plurality of battery cells 1 and has a thermally conductive bottom plate 3 on its underside, and a cooling plate 4 that is thermally coupled to a first face 3a of the bottom plate 3 that is thermally coupled to the lower end faces of the plurality of battery cells 1 and a second face 3b on the opposite side (the back side of the first face 3a).

[0023] (Battery Cell 1) The battery cell 1 is a rechargeable secondary battery cell with a cylindrical outer shape and positive and negative electrode terminals on both end surfaces. Multiple battery cells 1 are stacked to form a battery block 10. The battery block 10 in Figure 3 is a rectangular parallelepiped with multiple battery cells 1 arranged parallel to each other with both ends flush. The multiple battery cells 1 are electrically connected by lead plates, bus bars, etc. In the power supply system 100 in Figure 3, the battery cells 1 are cylindrical batteries 1A. The cylindrical batteries 1A are arranged parallel to each other in an outer case 2, with electrode terminals on both ends exposed to both sides of the outer case 2 and electrically connected by lead plates. The cylindrical battery 1A is constructed by housing an electrode assembly in a cylindrical outer can, filling it with electrolyte, and sealing the opening of the outer can with a sealing plate. The cylindrical battery 1A's positive and negative electrode terminals are located on the bottom of the outer can (both end surfaces) and an electrode located in the center of the sealing plate. While the power supply system 100 in Figure 3 uses cylindrical batteries 1A as battery cells 1, the present disclosure does not limit the battery cells 1 to cylindrical batteries 1A and can also use, for example, prismatic batteries 1B (Figure 13). The battery cells 1 are non-aqueous electrolyte secondary battery cells such as lithium-ion batteries. However, the present disclosure does not limit the battery cells 1 to lithium-ion batteries, and all currently used and future developed secondary batteries, such as other non-aqueous electrolyte secondary batteries and nickel-metal hydride batteries, can be used. The present disclosure can be used with all secondary batteries in which a cooling plate 4 is placed opposite the bottom surface of the battery cells 1, allowing the bottom surface of the battery cells 1 to be used as a cooling surface.

[0024] (External Case 2) The external case 2 houses multiple battery cells 1. The underside of the external case 2 is a thermally conductive bottom plate 3 that is thermally coupled to the end faces of the multiple battery cells 1. The external case 2 in Figure 3 has a holder 20 that positions the multiple stored battery cells 1 in a predetermined position and orientation, and the multiple battery cells 1 can be inserted into the battery storage section and positioned in a fixed position in a parallel orientation. The external case 2 can also house one or multiple battery blocks 10 in units of battery block 10, and position the multiple battery cells 1 in a fixed position in a parallel orientation.

[0025] The exterior case 2 in Figure 3 has a top surface, side surfaces 21, and a bottom plate 3 that closes the open bottom surface. The side surfaces 21 have an inner surface 21a facing the stored battery cells 1 and an outer surface 21b on the opposite side. The exterior case 2 may be configured so that the side surfaces 21 and the battery storage section, such as the holder 20, are integrated into one unit, or they can be separate components. The exterior case 2 may also be configured so that the side surfaces 21 and the bottom plate 3 are separate components. The side surfaces 21 can be integrated with the battery storage section, and in the case of the prismatic battery 1B shown in Figure 13, for example, the exterior case 2 includes bind bars, end plates, and other components that hold the multiple battery cells 1 in a predetermined position and orientation.

[0026] The outer case 2 has fixing portions 22 that fix the outer case 2 in a predetermined position. The fixing portions 22 are provided on part of the side surfaces 21 of the outer case 2 and have screw holes 24 for fixing the outer case 2 to the cooling plate 4. The outer case 2 in FIG. 1 is a simplified example and has a rectangular parallelepiped shape with a top surface, side surfaces 21, and a bottom plate 3 on the bottom surface. The outer case 2 in FIG. 1 is a box-shaped case with a rectangular top surface and two fixing portions 22 provided on each of a pair of opposing surfaces of the side surfaces 21. The outer case 2 houses multiple battery cells 1. For example, the battery cells 1 can be inserted into the outer case 2 from the open bottom side. Alternatively, the box-shaped outer case 2 can be divided into an upper case and a lower case to insert the battery cells 1, or the battery cells 1 can be inserted from the open bottom side of the outer case 2 with the bottom plate 3 integrated therein. The outer case 2 can be structured to house battery cells 1 or battery blocks 10. However, there are no limitations to the shape, size, configuration, and battery cell storage method of the exterior case 2. For example, the exterior case 2 can be configured with a flat surface, a curved surface, or a combination of these, and the exterior surface can be provided with irregularities, grooves, steps, slopes, etc. depending on the size and shape of the battery block and the shape of the main body on which the power supply system is mounted.

[0027] (Fixing portion 22) The fixing portion 22 in FIG. 1 fixes the outer case 2 to the cooling plate 4. The fixing portion 22 is provided on the side surface 21 of the outer case 2. The fixing portion 22 in FIG. 1 is provided on the outer surface 21b of the side surface 21 of the outer case 2. The fixing portion 22 in FIG. 1 has a convex shape that protrudes outward from the side surface 21. This fixing portion 22 ensures a rectangular parallelepiped (rectangular) shape as the battery storage shape within the side surface 21 while keeping the thickness of the side surface 21 constant or within a certain range. This maintains and improves the rigidity of the device and achieves high output while suppressing and reducing material and manufacturing costs. However, the side surface 21 may be thickened only in the area where the fixing portion 22 is provided, or the fixing portion 22 may be provided on the inner surface 21a of the side surface 21.

[0028] This disclosure does not specify the shape, size, or configuration of the fixing portion 22. For example, the horizontal cross-sectional shape of the fixing portion 22 can be a triangle ( FIGS. 4 , 5 , and 9 ), a rectangle ( FIG. 10 ), a trapezoid ( FIG. 7 ), a polygon, or a half or divided shape of any of these. It can also be a regular shape such as a semicircle ( FIG. 8 ), a semi-ellipse, or an irregular shape. In this disclosure, "shape" includes approximate shapes. The outer surface of the fixing portion 22 can be flat, curved, or a combination of flat and curved surfaces. For example, the fixing portion 22 can have chamfered corners, a shape that matches the shape and arrangement of the boss screws 26, and a curved surface where the fixing portion 22 connects to the side surface 21 ( FIG. 12 ). The bottom surface 23 of the fixing portion 22 can be flat, or can have steps, bumps, grooves, slopes, or the like. The bottom surface 23 of the fixing portion 22 can be shaped to match the shape and arrangement of the boss screws 26. For example, the bottom surface 23 of the fixing portion 22 can be configured so that the bottom surface of the boss screw 26 is positioned lower than the bottom surface other than the boss screw 26, and protrusions 31, which will be described later, protrude on both sides of the boss screw 26 (screw hole 24). The bottom surface of the boss screw 26 and the bottom surface of the protrusions 31 can be at the same height or at different heights. The bottom surface 23 of the fixing portion 22 can be shaped to match the shape of the cooling plate 4 to be connected and fixed, allowing the exterior case 2 to be stably fixed and improving the fixing strength.

[0029] The fixing portion 22 in Figure 4 has a triangular bottom surface 23 and horizontal cross-sectional shape, a boss screw 26 disposed in the central region of the fixing portion 22, and the apex corner (tip 22b) of the triangle is curved due to the thickness of the boss screw 26. This fixing portion 22 is shaped to match the shape of the boss screw 26 (screw hole 24), ensuring the fixing strength of the outer case 2 at a predetermined thickness. Also, while the fixing portion 22 in Figure 1 is a triangular prism with the same horizontal cross-sectional shape as the bottom surface 23, the fixing portion 22 can have a horizontal cross-sectional shape that is different from the bottom surface 23, or a horizontal cross-sectional shape that is partially different from the bottom surface 23. For example, the fixing strength and rigidity of the outer case 2 can be further improved by making the bottom surface 23 larger in area than the opposing top surface or middle cross-section.

[0030] The fixing portion 22 has a connecting portion 22a at the base where the fixing portion 22 is connected to the outer case 2, and a tip portion 22b at the tip of the fixing portion 22 that protrudes the most from the connecting portion 22a and is the furthest from the connecting portion 22a. The fixing portion 22 in FIG. 4 is connected to the outer case 2 via the connecting portion 22a. The fixing portion 22 in FIG. 4 has a shape such that the length (L1) of the connecting portion 22a that connects to the outer case 2 is longer than the length (L2, the length of the tangent to the curved surface in the figure) of the tip portion 22b at the bottom surface 23. The fixing portion 22 in FIG. 4 has a triangular bottom surface 23 that tapers from the relatively wide connecting portion 22a side to the narrow tip portion 22b side. Because the connecting portion 22a is wider than the tip portion 22b, the fixing portion 22 having the wide connecting portion 22a can sandwich the bottom plate 3 (protrusion 31) between itself and the cooling plate 4 and fix it to the cooling plate 4, together with the side surface 21, in the area close to the side surface 21, and this extremely simple configuration can efficiently improve the fixing strength and rigidity of the exterior case 2. In addition, as shown in Figure 12, the connecting portion 22a side of the fixing portion 22 can be made a smoothly curved surface, making it possible to further increase the length (L1) of the connecting portion 22a on the base side, which can contribute to further improving the fixing strength and rigidity of the exterior case 2.

[0031] The convex fixing portions 22 that protrude outward from the side surfaces 21 make it possible to provide protrusions 31 (described below) on the bottom plate 3 that overlap the fixing portions 22. The protrusions 31 increase the area of ​​the bottom plate 3 that is sandwiched and fixed between the battery block 10 and the cooling plate 4. In particular, the area of ​​the connecting portions 31a at the base side, which are connected in the same way as the fixing portions 22, can be increased, allowing the bottom plate 3 to be sandwiched between the fixing portions 22, the side surfaces 21, and the cooling plate 4. Furthermore, it is possible to provide screw holes 34 in the protrusions 31 and fasten the protrusions 31 to the fixing portions 22 by threading screws 35. Together, these features firmly secure the bottom plate 3, which is interposed and fixed between the multiple battery cells 1 and the cooling plate 4, to the exterior case 2, efficiently improving the rigidity of the power supply system 100 despite its simple structure.

[0032] The fixing portion 22 in FIG. 4 has a threaded hole 24 through which a screw or shaft (hereinafter referred to as a screw 25) is inserted. The outer case 2 is fixed to the cooling plate 4 via the screw 25 inserted through the threaded hole 24. The threaded hole 24 can be provided with a female thread or a shaft hole by, for example, press-fitting a spacer or a nut into a boss of the molded product during or after molding, and the screw 25 can be inserted to fix the outer case 2 to the cooling plate 4. The threaded hole 24 in FIG. 4 is provided in a central region 29 of the fixing portion 22. The central region 29 refers to the region other than the outer periphery that includes the center or center of gravity of the fixing portion 22. The fixing portion 22 in FIG. 4 has a boss screw 26 and a boss screw connecting portion 27 that connects the boss screw 26 to the outer case 2. The screw hole 24 is provided in the boss screw 26. The boss screw connecting portion 27 in FIG. 4 is connected to the outer edge of the boss screw 26, connects the boss screw 26 to the outer case 2, and is composed of two triangles on the connecting portion 22a side that support and fix the boss screw 26. The two triangular boss screw connecting portions 27 connect the boss screw 26 to the outer case 2. Each fixing portion 22 can be provided with one or more screw holes 24. FIG. 11 shows an example of a fixing portion 22 that opens two screw holes 24. When the fixing portion 22 opens multiple screw holes 24, the multiple screw holes 24 can be opened with a gap between them, or the multiple screw holes 24 can be opened closely together. As the area of ​​the fixing portion 22 that opens multiple screw holes 24 increases, the area of ​​the protrusion 31 can also be increased, allowing for a variety of screw holes 34 to be opened.

[0033] The outer case 2 can have one or more fixing portions 22 on the side surfaces 21. By providing a fixing portion 22 on each of a pair of opposing side surfaces 21, the outer case 2 can be arranged on both opposing side surfaces 21, spaced apart by the distance of one side between the opposing side surfaces 21, thereby efficiently improving the fixing strength of the outer case 2. If the side surfaces 21 of the outer case 2 are rectangular, the fixing portion 22 can be provided on either or both of the pair of opposing short side surfaces 21 or the pair of opposing long side surfaces 21. Similarly, if the side surfaces 21 are square, the fixing portion 22 can be provided on either of the pair of opposing side surfaces 21. The outer case 2 can have fixing portions 22 protruding along screw holes 24 on each of a pair of side surfaces 21 that intersect with the longitudinal direction. The outer case 2 can have one or more fixing portions 22 on each of the opposing side surfaces 21. As shown in Figure 4, the exterior case 2 has a plurality of fixing portions 22 (two in Figure 4) on each of the opposing side surfaces 21. By arranging the fixing portions 22 at or near the corners of the side surfaces 21, the fixing portions 22 can be arranged at intervals close to the diagonal of the side surfaces 21 and at positions close to both ends of the diagonal, more efficiently improving the fixing strength of the exterior case 2. Improving the fixing strength of the three-dimensional exterior case 2 leads to improved rigidity of the power supply system. The corners refer to the areas from the corners to the center of one surface of the side surfaces 21, including the corners and the vicinity of the corners.

[0034] The fixing portion 22 in Fig. 2 fixes the outer case 2 to the cooling plate 4. However, the fixing portion 22 can also fix the outer case 2 to something other than the cooling plate 4. For example, the fixing portion can fix the outer case 2 to the case, or fix the outer case 2 to the case and the cooling plate 4. Alternatively, a pair of outer cases 2 can be arranged with the cooling plate 4 between them, and the fixing portion 22 can fix each outer case 2 to each other, and each outer case 2 can be fixed to the cooling plate 4 (Fig. 14).

[0035] The fixing portions 22 in Figure 2 fasten (thread) screws 25 to secure the outer case 2 to the cooling plate 4. The fixing portions 22 in Figure 2 have screw holes 24 through which the screws 25 are inserted, and the outer case 2 is secured to the cooling plate 4 via the screws 25 that pass through the screw holes 24. The screws 25 inserted into the screw holes 24 of the fixing portions 22 are threaded into the cooling plate 4, thereby easily and firmly securing the outer case 2. The method of fastening the outer case 2 to the cooling plate 4 by threading the fixing portions 22 secures the bottom plate 3 between the cooling plate 4 and multiple battery cells 1 arranged in predetermined positions in the outer case 2, thereby reliably securing the outer case 2 to the cooling plate 4. Furthermore, threading the fixing portions 22 to the cooling plate 4 strengthens the degree of contact between the two, thereby improving the fixing strength of the bottom plate 3 that is sandwiched between the cooling plate 4 and multiple battery cells 1 housed in the outer case 2, and improving rigidity via the bottom plate 3. Furthermore, by improving the thermal bonding between the end faces of the multiple battery cells 1 and the bottom plate 3, and between the bottom plate 3 and the cooling plate 4, thermal conductivity is improved, preventing or suppressing a decrease in cooling performance, and achieving both rigidity and thermal conductivity. Note that the fixing parts 22 can fix the exterior case 2 by methods other than screwing.

[0036] (Bottom Plate 3) The bottom plate 3 is disposed below the multiple battery cells 1 and is interposed between the multiple battery cells 1 and the cooling plate 4. The bottom plate 3 has a first surface 3a that is thermally coupled to the end faces of the multiple battery cells 1 and a second surface 3b that is thermally coupled to the cooling plate 4 on the opposite side to the first surface 3a. The first surface 3a and the second surface 3b can be shaped to match the shape of the object to be thermally coupled. The bottom plate 3 is a member that supports the multiple battery cells 1 and reinforces the exterior case 2 to improve its rigidity, and is also a thermally conductive member that conducts heat generated by the multiple battery cells 1 to the cooling plate 4 and dissipates it to the outside. The bottom plate 3 is sandwiched between the battery block 10 and the cooling plate 4 and is securely fixed in a stable state, so that the bottom plate 3 supports the battery block 10, reducing the burden on the cooling plate 4 that is directly borne by the weight of the battery block 10, and improving the rigidity of the power supply system. The bottom plate 3 is made of a material and has a thickness that can support the battery block 10 and reduce the burden on the cooling plate 4, and is selected appropriately depending on the mass of the battery block 10. Furthermore, by making the bottom plate 3 thermally conductive, it is possible to suppress or reduce the reduction in cooling performance caused by the cooling plate 4 even when the bottom plate 3 is present, and it is possible to achieve a structure that achieves both rigidity and thermal conductivity with the bottom plate 3. The bottom plate 3 is preferably made of a material with high thermal conductivity, such as aluminum, copper, or an alloy containing either of these.

[0037] (Protrusion 31) The bottom plate 3 has a protrusion 31 that protrudes from a portion thereof along the end face of the fixing portion 22. The bottom plate 3 has a bottom plate main body 30, which is the main body of the bottom plate 3, and a protrusion 31 on the periphery of the bottom plate main body 30. The protrusion 31 extends outward beyond the inner surface 21a of the side surface 21 of the connected outer case 2. The protrusion 31 is a portion that extends outward beyond the inner surface 21a of the side surface 21 of the outer case 2. By having the protrusion 31 on the bottom plate 3, the protrusion 31 can be sandwiched between the fixing portion 22 of the outer case 2 and the cooling plate 4, thereby fixing the outer case 2 to the cooling plate 4, thereby improving fixing strength and rigidity. This is because the outer case 2 can be fixed to the cooling plate 4 by sandwiching the protrusion 31 that extends outward from the side surface 21 in addition to the thickness of the side surface 21.

[0038] The protrusions 31 in Figure 5 extend further outward than the outer surface 21b of the side surface 21 of the connected exterior case 2. This allows the area of ​​the protrusions 31 to be further enlarged. The wider area of ​​the protrusions 31 improves thermal conductivity. This makes it easier for the protrusions 31 to draw in heat from the multiple battery cells 1 and conduct it to the cooling plate 4, thereby maintaining the cooling performance of the cooling plate 4. Furthermore, the protrusions 31 that extend outward than the outer surface 21b of the side surface 21 can extend to the outer edge where no battery cells 1 are present. Furthermore, by separating the protrusions 31 horizontally from the bottom surfaces of the multiple battery cells 1, they are positioned internally near the side surface 21, improving the heat dissipation and heat dissipation efficiency of the multiple battery cells 1, which tend to trap heat.

[0039] This disclosure does not specify the shape, size, or configuration of the protrusion 31. For example, the horizontal cross-sectional shape of the protrusion 31 can be one or more triangles ( FIGS. 5 and 9 ), squares ( FIG. 10 ), trapezoids ( FIG. 7 ), polygons, or half or divided shapes of any of these. It can also be regular shapes such as semicircles ( FIG. 8 ), semi-ellipses, or irregular shapes. All shapes are considered to include approximate shapes. The protrusion 31 can be configured by arranging or connecting multiple shapes of the same or different shapes. The protrusion 31 in FIG. 5 is configured by connecting two line-symmetric triangles (two peaks). The outer surface of the protrusion 31 can be flat, curved, or a combination of flat and curved surfaces. For example, the corners of the protrusion 31 can be chamfered, or the shape can be configured to match the shape and arrangement of the boss screw 26, and the connecting portion 31 a of the protrusion 31 can be curved. Each protrusion 31 can have one or more screw holes 34. The protrusion 31 in Fig. 5 is a part of the bottom plate 3 that protrudes along the end surface of the fixed portion 22. The protrusion 31 is shaped to protrude on both sides of the screw hole 24 of the fixed portion 22, and has screw holes 34 on both sides of the screw hole 24. Each protrusion 31 in Fig. 5 has two screw holes 34 opened in close proximity to both sides of the screw hole 24. The protrusion 31 in Fig. 5 has a shape in which two triangles are linked together so as to fit around the periphery of the boss screw 26 (screw hole 24) of the fixed portion 22, and each of the two triangles on both sides of the screw hole 24 has one screw hole 34 opened.

[0040] The protrusion 31 in FIG. 5 is an area surrounded by a screw hole periphery 36 around the screw hole 24, a fixing portion outer edge 37 along the outer edge of the fixing portion 22, and a base-side connecting portion 31a where the protrusion 31 is connected to the bottom plate body 30. The screw hole periphery 36 is arc-shaped and curves along the circular screw hole 24 or boss screw 26. The fixing portion outer edge 37 is formed by two triangles on both sides with the connecting portion 31a as the base. The left hypotenuse of the left triangle and the right hypotenuse of the right triangle are arranged along the outer edge of the triangular fixing portion 22 (the respective hypotenuses of the left and right approximate triangles of the boss screw connecting portion 27), and the right hypotenuse of the left triangle and the left hypotenuse of the right triangle are connected along the outer edge of the boss screw 26. This configuration ensures both rigidity and thermal conductivity while ensuring the connection strength of the boss screw 26. The protrusion 31 in FIG. 5 has a shape in which two triangles are connected by the arc-shaped screw hole periphery 36.

[0041] The protrusion 31 has a connecting portion 31a on the base side where the protrusion 31 is connected to the bottom plate body 30, and a tip portion 31b on the tip side of the protrusion 31 that protrudes the most from the connecting portion 31a and is the furthest from the connecting portion 31a. The protrusion 31 is connected to the bottom plate body 30 via the connecting portion 31a. The protrusion 31 in FIG. 5 has a shape in which the length (W1) of the connecting portion 31a that connects to the bottom plate body 30 is longer than the length (W2, the length of the tangent to the curved surface in the figure) of the tip portion 22b on the tip side of the protrusion 31. The protrusion 31 in FIG. 5 has two triangles that are connected near the base on the connecting portion 31a side to form a relatively wide connecting portion 31a, and each triangle has a tapered shape from the connecting portion 31a side to the narrow tip portion 31b side (the apex side). Because the connecting portion 31a is wider than the tip portion 31b, the wide connecting portion 31a can be clamped and fixed together with the side surface 21 in an area close to the side surface 21. This extremely simple configuration contributes greatly to efficiently improving rigidity. The wider area of ​​the connecting portion 31a at the base side allows it to be clamped between the fixing portion 22 and the cooling plate 4, and also provides space for providing screw holes 34 at the connecting portion 31a or in a position close to the connecting portion 31a. The protrusions 31 protrude on both sides of the screw holes 24, are close to both sides of the screw holes 24, and the screw holes 34 are opened in the connecting portion 31a and fastened by threading screws 35. This efficiently improves the fastening strength and rigidity of the bottom plate 3 and the outer case 2. The protrusions 31 are threadedly engaged with the fixing portion 22 with the screws 35 to fasten the bottom plate 3 to the outer case 2, and the outer case 2 is further fastened to the cooling plate 4 by threading screws 25 of the fixing portion 22, thereby efficiently improving the rigidity of the power supply system 100. 12, the length (W1) of the base side of the protrusion 31 can be further increased by forming a smooth curved surface on the side of the protrusion 31 facing the connecting portion 31a, thereby contributing to further improving the rigidity of the power supply system 100.

[0042] The protrusions 31 also increase the area of ​​the bottom plate 3. In particular, the protrusions 31 are provided on the periphery of the bottom plate body 30 and protrude outward from the connecting portions 31a, which are close to the battery block 10 and have a significant impact on heat dissipation, thereby improving thermal conductivity. Furthermore, by protruding along the end faces of the fixing portions 22, the area and shape of the protrusions effectively contribute to rigidity and thermal conductivity while minimizing the increase in material costs due to the increased area of ​​the bottom plate 3. This configuration achieves both rigidity and thermal conductivity.

[0043] The protrusions 31 overlap at least a portion of the bottom surface 23 of the fixing portion 22 in a plan view. For example, the protrusions 31 can overlap 10% or more of the bottom surface 23 of the fixing portion 22, preferably 20% or more. The greater the overlap area, the greater the contact area between the bottom plate 3 and the outer case 2. In particular, the protrusions 31 on the outer edge of the bottom plate 3 can increase the contact area with the fixing portion 22 near the side surface 21, thereby improving the fixing strength of the bottom plate 3 between the battery block 10 housed in the outer case 2 and the cooling plate 4. Furthermore, the greater the overlap, the more space there is for providing screw holes 34 in the protrusions 31, allowing screws 35 to be threaded into the protrusions 31 to fix them to the fixing portion 22, improving the fixing strength of the bottom plate 3 and, ultimately, the rigidity of the power supply system 100. Furthermore, the improved rigidity improves the thermal conductivity of the bottom plate 3 in a stable, tightly fitted state, achieving both rigidity and thermal conductivity.

[0044] The connecting portion 31a of the protrusion 31 can overlap, for example, 60% or more of the bottom surface 23 of the fixing portion 22 with which the connecting portion 31a comes into contact, preferably 70% or more, more preferably 80% or more, and optimally almost the entire range of the bottom surface 23 of the fixing portion 22 with which the connecting portion 31a of the protrusion 31 comes into contact, but without both ends of the connecting portion 31a of the protrusion 31 protruding. By overlapping the bottom surface 23 of the fixing portion 22 with the connecting portion 31a on the base side that connects to the bottom plate body 30 over a wide width (area), the protrusion 31 can also contribute more efficiently to improving rigidity and thermal conductivity near the tip portion 31b, thereby achieving both.

[0045] The protrusions 31 can be shaped to match the shape of the bottom surface 23 of the fixing portion 22. The protrusions 31 in FIG. 5 are arranged within the bottom surface 23 of the fixing portion 22. This power supply system 100 efficiently improves both rigidity and thermal conductivity without the protrusions 31 extending beyond the bottom surface 23 of the fixing portion 22. This contributes to improving rigidity and thermal conductivity while suppressing increases in the material cost of the bottom plate 3, and also contributes to making the power supply system 100 more compact. However, the protrusions 31 can be larger than the bottom surface 23 of the fixing portion 22, and can also be sized and shaped so that they extend beyond the bottom surface 23 of the fixing portion 22. Furthermore, the protrusions 31 can be provided somewhere other than the screw holes 24 or the boss screws 26. By providing the protrusions 31 in FIG. 5 on the outer periphery of the boss screws 26, the flatness of the contact surface of the boss screws 26 can be maintained, and the rigidity achieved by fastening the screws 25 can be maintained.

[0046] The bottom plate 3 in FIG. 5 is fixed to the exterior case 2. The bottom plate 3 in the figure is fixed to the exterior case 2 by screwing with screws 35. Screwing the bottom plate 3 to the exterior case 2 can improve the rigidity of the power supply system 100. The bottom plate 3 is fixed by fastening screws at predetermined positions and intervals on the side surface 21 of the exterior case 2 or on the interior side thereof. For example, in addition to the four corners of the rectangular shape, the bottom plate 3 in FIG. 5 is screwed at four locations on each long edge and two locations on each short edge (a total of 16 locations). Furthermore, each of the protrusions 31 protruding from both sides of the screw holes 24 adjacent to the screw holes 24 of the four fixing portions 22 is screwed at two locations on each side of the screw holes 24, meaning that the bottom plate 3 is screwed to the side surface 21 of the exterior case 2 at a total of 24 locations. By firmly fixing the bottom plate 3 to the outer case 2, the bottom plate 3 becomes a bottom plate that closes the bottom surface 23 of the outer case 2, and the three-dimensional shape of the outer case 2 and the bottom plate 3 can increase rigidity and reduce the burden of the weight of the battery block 10 on the cooling plate 4.

[0047] In FIG. 5 , the protrusion 31 is fixed to the fixing portion 22 by screwing. The protrusion 31 can have a screw hole 34 formed therein, and the screw hole 34 can be formed at a position overlapping the protrusion 31. The protrusion 31 in FIG. 5 protrudes on both sides of the screw hole 24, and the screw hole 34 is formed in the connecting portion 31a adjacent to both sides of the screw hole 24. By providing all or part of the screw hole 34 within the range of the protrusion 31, the screw 35 that fixes the bottom plate 3 to the outer case 2 can be screwed and fixed at a position adjacent to the connecting portion 31a and adjacent to the screw hole 24 of the fixing portion 22, thereby efficiently increasing the natural frequency and efficiently improving rigidity. The protrusion 31 can be screwed to the fixing portion 22 (outer case 2), and further screwed to the cooling plate 4. This improves fixing strength and rigidity. When the exterior case 2 and the cooling plate 4 are screwed together, the protrusions 31, which are extensions of a portion of the bottom plate 3, are clamped, and the protrusions 31 are further screwed into the fixing portions 22, so that the clamped bottom plate 3 is securely fixed physically, and rigidity can be improved via the bottom plate 3. The screw holes 34 of the protrusions 31 and the screws 35 are shaped and configured so as not to impede thermal coupling with the cooling plate 4 or the close contact between the bottom plate 3 and the cooling plate 4.

[0048] The protrusions 31 in Figure 5 are fixed by contacting the fixing portion 22. By contacting and fixing the protrusions 31 to the fixing portion 22, they can be firmly fixed, improving rigidity. By screwing the protrusions 31 together, the fixing strength is improved and the degree of adhesion is increased. As a result, the thermal coupling between the end faces of the multiple battery cells 1 and the bottom plate 3, and between the bottom plate 3 and the cooling plate 4, is improved, improving thermal conductivity and preventing or suppressing a decrease in cooling performance, thereby achieving both rigidity and thermal conductivity in the power supply system 100 with the bottom plate 3 interposed therebetween.

[0049] A comparison was made between the first embodiment ( FIG. 5 ) and the comparative example ( FIG. 6 ) by analyzing the resonant frequency (natural frequency). In the first embodiment ( FIG. 5 ), the bottom plate 3 has a protrusion 31 that overlaps the fixing portion 22, and the protrusion 31 is fixed to the fixing portion 22 by threaded engagement with a screw 35. In contrast, in the comparative example ( FIG. 6 ), the bottom plate 3 does not have a protrusion 31, and this portion is not threaded with a screw 35. In both cases, the same conditions were used, except for the presence or absence of the protrusion 31 and the presence or absence of the threaded engagement with the screw 35, such as 160 battery cells 1, a weight of 20 kg, and four fixing portions 22, two on each of the opposing short side surfaces 21 of the outer case 2. Furthermore, in both cases, the bottom plate 3 is fixed to the outer case 2 by 16 threaded engagements near the periphery, excluding the threaded engagement of the protrusion 31. The natural frequency in the vertical direction (up-down direction) was around 100 Hz in the comparative example ( FIG. 6 ), while a value of 200 Hz or higher was obtained in the first embodiment ( FIG. 5 ). In the first embodiment ( FIG. 5 ), the bottom plate 3 has four protrusions 31, each of which protrudes on both sides of the screw hole 24. The protrusions 31 are secured to the fixed portion 22 by engaging screws 35 so that they engage the protruding portions on both sides of the screw hole 24. The above numerical values ​​confirm the significant effect of improving rigidity achieved by these measures. By slightly enlarging the bottom plate 3 to accommodate the protrusions 31 and engaging the screws 35 at the positions shown in the figure, the effect of improving rigidity is significant while suppressing increases in component and manufacturing costs, and the cost-effectiveness is therefore very high. The power supply system 100 of the present disclosure can suppress vertical vibration of the heavy battery block 10 due to this improved rigidity. Furthermore, in a heat dissipation measurement test, the first embodiment ( FIG. 5 ) obtained better results than the comparative example ( FIG. 6 ). The presence of the protrusions 31 improves thermal conductivity, improves the adhesion between the bottom plate 3 and the bottom surface of the battery block 10, and between the bottom plate 3 and the cooling plate 4, and improves the thermal bonding state of each.It is also thought that suppressing vertical vibration of the battery block 10 contributes to the stable cooling performance of the cooling plate 4.

[0050] The bottom plate 3 can have one or more protrusions 31. The bottom plate 3 can have the same number of protrusions 31 as the number of fixing portions 22 or less. The bottom plate 3 in FIG. 5 has the same number of protrusions 31 as the fixing portions 22, and each protrusion 31 is arranged in the same position as each fixing portion 22, so that the multiple protrusions 31 overlap the bottom surfaces 23 of the fixing portions 22.

[0051] The bottom plate 3 in the figure has a protrusion 31 that protrudes in the same plane. This not only reduces the cost of the component, but also allows the protrusion 31 to be tightly sandwiched between the fixing part 22 and the cooling plate 4, thereby increasing the fixing strength and rigidity of the exterior case 2.

[0052] Other embodiments are shown in Figures 7 to 12. In Figure 5, the basic form for comparison with the other embodiments, the fixing portion 22 is triangular, with a screw hole 24 provided in the central region 29. The protrusions 31 are two triangles shaped to match the shape of the fixing portion 22, with a screw hole 34 provided in each triangle. In Figure 7, the fixing portion 22 is trapezoidal, with the length (L2) of the tip 22b being longer than in Figure 5. The connecting portion 22a at the bottom of the trapezoid can be made longer to increase the area of ​​the protrusions 31. In Figure 8, the fixing portion 22 is semicircular, with the protrusions 31 shaped to fit the shape of the fixing portion 22 along the periphery of the boss screw 26. The protrusions 31 can protrude outward beyond the outermost point of the boss screw 26 and can have two or more screw holes 34. In Figure 9, the fixing portion 22 is a larger triangle than in Figure 5, with a screw hole 24 provided in the central region 29. The protrusion 31 is triangular to match the shape of the fixing portion 22, protrudes outward from the outermost point of the boss screw 26, and has one additional screw hole 34 near the apex of the two screw holes 34 at the base of the triangle. In Figure 10, the fixing portion 22 is rectangular, and the screw hole 24 is provided in the central region 29. The protrusion 31 is rectangular to match the shape of the fixing portion 22, protrudes outward from the outermost point of the boss screw 26, and has a total of four screw holes 34 near the four corners of the rectangle. In Figure 11, the fixing portion 22 has two screw holes 24 opened at intervals, and the protrusion 31 is shaped to match the shape of the fixing portion 22, and has three screw holes 34. In Figures 9 to 11, the protrusion 31 can be more firmly fixed by threading screws 35 at three or four points. 12, both ends of the connecting portion 22a of the fixing portion 22 are widened to both sides, forming a smoothly curved surface with a longer length (L1) of the connecting portion 22a on the base side, and the protrusion 31 is shaped to match the shape of the fixing portion 22. The shape and size of the protrusion 31 can be determined efficiently to match the shape of the fixing portion 22. Depending on the shapes and sizes of the fixing portion 22 and the protrusion 31, one or more screw holes 24 can be opened in the fixing portion 22, and one or more screw holes 34 can be opened in the protrusion 31.

[0053] (Insulating Sheet 6) The power supply system 100 of FIG. 2 further includes an insulating sheet 6 between the cooling plate 4 and the battery block 10. In FIG. 2, the insulating sheet 6 is interposed between the battery block 10 and the cooling plate 4. The insulating sheet 6 is made of a material that is both insulating and has excellent thermal conductivity. By interposing the insulating sheet 6 between the battery block 10 and the cooling plate 4, electrical insulation is provided between the battery block 10 and the cooling plate 4. In particular, when the battery cell 1 outer can is made of metal and the cooling plate 4 is also made of metal, insulation is required to prevent electrical conduction at the bottom of the battery cell 1. For example, the surface of the outer can can be insulated by covering it with heat-shrink tubing or the like, and an insulating insulating sheet 6 can be interposed to further improve insulation and enhance safety and reliability. The insulating sheet 6 preferably has a certain degree of elasticity, and examples of the insulating sheet 6 include acrylic, urethane, epoxy, and silicone resins. By making the insulating sheet 6 elastic, the surface of the insulating sheet 6 can be elastically deformed, eliminating gaps at the contact surface between the battery block 10 and the cooling plate 4 and improving the thermal coupling. One or more insulating sheets can be interposed. The insulating sheet 6 can be a sheet, film, paste, or the like. To reliably maintain thermal conduction and insulation, multiple insulating sheets 6 can be interposed, for example, by adding films. The insulating sheet 6 does not necessarily need to be provided, and if sufficient insulation is achieved, the insulating sheet 6 can be omitted.

[0054] (Cooling Plate 4) The cooling plate 4 is a heat sink that conducts heat from the battery cells 1 to the outside. The cooling plate 4 is thermally coupled to the second surface 3b of the bottom plate 3. The power supply system 100 cools the battery cells 1 by conducting heat generated by the multiple battery cells 1 to the cooling plate 4 via the bottom plate 3 and dissipating the heat to the outside. The cooling plate 4 may be equipped with, for example, refrigerant piping. The cooling plate 4 may incorporate cooling pipes, which are refrigerant piping made of copper, aluminum, or the like that circulates a liquefied refrigerant as a heat exchanger. The cooling pipes are thermally coupled to the top plate of the cooling plate 4, for example, and insulating material may be provided between the cooling pipes and the bottom plate to provide thermal insulation. The cooling plate 4 may also be equipped with a refrigerant cooling function or may be constructed solely from a metal plate. For example, it may be configured with a shape that provides excellent heat dissipation and heat transfer, such as a metal body with heat dissipation fins. Alternatively, it may be made of an insulating heat transfer sheet, rather than metal.

[0055] (Embodiment 2) Figure 13 shows a power supply system 200 pertaining to embodiment 2. The power supply system 200 in Figure 13 is similar to embodiment 1, except that the battery cells 1 are prismatic batteries 1B, and the exterior case 2 includes bind bars, end plates, fastening members, etc. that hold multiple prismatic batteries 1B in a predetermined position and orientation, and the above description applies. For example, by providing sufficient strength, such as by making the exterior case 2 out of metal, it is possible to fasten end plates to the exterior case 2 and fasten the battery block 10 together. With this configuration, the exterior case 2 also functions as a fastening member, allowing for a more compact power supply system 200.

[0056] (Embodiment 3) Fig. 14 shows a power supply system 300 according to embodiment 3. It is possible to combine a plurality of power supply systems 100 and 200 shown in embodiments 1 and 2. For example, in the power supply system 300 shown in Fig. 14, a cooling plate 4 is disposed between a pair of exterior cases 2. A cooling plate 4 is disposed on the underside of each of the pair of exterior cases 2, with a bottom plate 3 interposed therebetween. One or a plurality of cooling plates 4 can be disposed, and the same or different cooling plates 4 can be disposed.

[0057] The present disclosure can be usefully used as a power supply system that can efficiently cool secondary battery cells with a cooling plate in an apparatus that cools multiple high-output, heavy secondary battery cells with a cooling plate, or as a power supply system with increased rigidity, or as a power supply system that combines rigidity and thermal conductivity, or in equipment or devices that incorporate any of these.

[0058] DESCRIPTION OF SYMBOLS 100, 200, 300...Power supply system 1...Battery cell 1A...Cylindrical battery 1B...Prismatic battery 2...External case 3...Bottom plate 3a...First surface 3b...Second surface 4...Cooling plate 5...Cooling mechanism 6...Insulating sheet 10...Battery block 20...Holder 21...Side surface 21a...Inner surface 21b...Outer surface 22...Fixing portion 22a...Connecting portion 22b...Tip portion 23...Bottom surface 24...Screw hole 25...Screw 26...Boss screw 27...Boss screw connecting portion 29...Central region 30...Bottom plate body 31...Protrusion 31a...Connecting portion 31b...Tip portion 34...Screw hole 35...Screw 36...Screw hole periphery 37...Fixing portion outer edge portion

Claims

1. A power supply system comprising: a plurality of battery cells, each having an end face; an exterior case that houses the plurality of battery cells; a thermally conductive bottom plate whose underside is thermally coupled to the end faces of the plurality of battery cells; and a cooling plate that is thermally coupled to a second surface of the bottom plate opposite a first surface that is thermally coupled to the end faces of the plurality of battery cells.

2. A power supply system as claimed in claim 1, wherein the exterior case has a fixing portion, a part of a side of the fixing portion is provided with a screw hole for fixing to the cooling plate, and the bottom plate has a protrusion, a part of the protrusion protruding so as to follow the end face of the fixing portion.

3. A power supply system as claimed in claim 2, wherein the exterior case has the fixing parts protruding along the screw holes on a pair of opposing side surfaces, and the bottom plate has the protrusions protruding on both sides of the screw holes on a pair of opposing side surfaces.

4. A power supply system as claimed in claim 2, wherein the outer case has fixing parts protruding along the screw holes on a pair of side surfaces intersecting the longitudinal direction, and the bottom plate has protruding parts protruding on both sides of the screw holes on each of its longitudinal edges.

5. A power supply system according to claim 2, wherein said bottom plate has said protruding portion protruding in the same plane.

6. A power supply system according to claim 2, wherein the protrusion is fixed to the exterior case by screwing.

7. A power supply system according to any one of claims 2 to 6, wherein a part of said protrusion is sandwiched between said fixing part and said cooling plate.

8. A power supply system according to claim 7, wherein the exterior case has a bottom plate formed as a separate member.

9. A power supply system comprising: a plurality of battery cells; an outer case that houses the plurality of battery cells; and a cooling plate, wherein each of the plurality of battery cells has an end face; the outer case houses the plurality of battery cells and includes a bottom plate on a first surface of the outer case, the bottom plate being a thermally conductive member that is thermally coupled to the end faces of each of the plurality of battery cells; the bottom plate includes a first surface and a second surface opposite the first surface of the bottom plate, the first surface of the bottom plate being thermally coupled to the end faces of each of the plurality of battery cells; and the cooling plate is thermally coupled to the second surface of the bottom plate.

10. A power supply system as described in claim 9, wherein the outer case includes a second surface intersecting with the first surface of the outer case and is provided with a fixing portion on the second surface of the outer case, the fixing portion includes an end surface, and a screw hole is opened in the end surface of the fixing portion for fixing to the cooling plate, and the bottom plate includes a third surface and is provided with at least one protrusion protruding from the third surface of the bottom plate so as to face the end surface of the fixing portion, and the third surface of the bottom plate intersects with the first surface of the bottom plate and the second surface of the bottom plate.

11. A power supply system as described in claim 10, wherein the outer case has a pair of opposing second faces including the second face of the outer case, each of the fixing portions protruding along the periphery of the screw hole in a direction perpendicular to the second face of the outer case, and the bottom plate has a pair of opposing third faces including the three faces of the bottom plate, and each of the pair of opposing third faces has at least two protrusions protruding on both sides of the screw hole, and the at least two protrusions include the at least one protrusion.

12. A power supply system as described in claim 11, wherein the outer case is a rectangular parallelepiped with the first surface being rectangular, the pair of opposing second surfaces of the outer case are surfaces that intersect with the longitudinal direction of the outer case, and the bottom plate is provided with at least two protrusions on edges in the longitudinal direction.

13. A power supply system according to claim 10, wherein said bottom plate has at least two projections projecting in the same plane, said at least two projections including said at least one projection.

14. A power supply system as described in claim 10, wherein the bottom plate has a screw hole, and the at least one protrusion provided on each edge of the bottom plate is screwed into the screw hole of the bottom plate by a screw, thereby fixing the bottom plate to the exterior case.

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