Battery module and battery pack

Abstract

To provide a battery module that facilitates miniaturization of the busbar. [Solution] The battery module 20 comprises a plurality of batteries (secondary batteries) 31, one or more busbars 40 that electrically connect the plurality of batteries 31, and a cooling plate 50 that has one or more passages 51 through which a coolant flows and contacts the busbars 40. Each of the plurality of batteries 31 comprises an electrode body, an outer casing that houses the electrode body, a lid that seals the opening of the outer casing, and a positive electrode terminal 42 and a negative electrode terminal 43 that are inserted through a pair of through holes provided in the lid, insulated from the lid, and electrically connected to the electrode body. One of the positive electrode terminal 42 and the negative electrode terminal 43 is connected to the busbars 40.

Description

Technical Field

[0001] The present disclosure relates to a battery module and a battery pack including a plurality of secondary batteries electrically connected by bus bars. Background Art

[0002] Conventionally, as a battery pack, there is one described in Patent Document 1 (see FIG. 5). This battery pack includes a plurality of prismatic batteries and a plurality of cooling plates. The plurality of batteries are arranged in a row in the same orientation, and the cooling plate is arranged between each two adjacent batteries. The cooling plate has cooling passages extending in a direction orthogonal to the height direction of the battery pack. This battery pack cools each battery by dissipating heat generated during charging and discharging of the batteries to the space within the cooling passages. Prior Art Literature Patent Literature

[0003] Patent Document 1 Japanese National Publication of International Patent Application No. 2017-534143 Summary of the Invention Problem to be Solved by the Invention

[0004] During rapid charging of batteries, a large current flows inside the batteries, and large Joule heat is generated inside the batteries. Here, if the heat capacity of the bus bars that electrically connect the batteries is increased, the Joule heat can be efficiently conducted out of the batteries, so thermal degradation of the batteries can be suppressed, and the inside of the batteries can be efficiently cooled. However, increasing the heat capacity of the bus bars leads to an increase in the size of the bus bars, which consequently causes an increase in the size of the battery pack and also increases the manufacturing cost of the battery pack.

[0005] Therefore, an object of the present disclosure is to provide a battery module and a battery pack that facilitate efficient cooling of the inside of secondary batteries and facilitate size reduction of bus bars. Means for Solving the Problem

[0006] To solve the above problems, the battery module of this disclosure comprises a plurality of batteries, one or more busbars electrically connecting each of the plurality of batteries, and a cooling plate thermally connected to the busbars. The plurality of batteries comprises an electrode body, a housing for housing the electrode body, and a pair of output terminals electrically connected to the electrode body and located on the first surface of the housing, with one of the pair of output terminals connected to the busbar. [Effects of the Invention]

[0007] According to the battery module described herein, it is easier to efficiently cool the inside of the secondary battery, and the busbars can also be made smaller. [Brief explanation of the drawing]

[0008] [Figure 1] This is a schematic perspective view of a part of a battery pack according to one embodiment of the present disclosure, viewed from the bottom. The lower part of the side wall of the pack case and the bottom of the pack case are omitted from the illustration, and the internal structure of the lower part of the battery pack is visible. [Figure 2] This figure shows a portion of the schematic cross-sectional view along line AA in Figure 1, and is a schematic cross-sectional view representing a part of the battery module and a cooling plate. [Figure 3] This figure shows an example of simulation results illustrating the degree of cooling of a battery's current cutoff device, and also shows an example of simulation results comparing top surface cooling, terminal cooling, and bottom surface cooling. [Figure 4] This figure shows an example of simulation results illustrating the degree of cooling of the top surface of a battery, and also shows an example of simulation results comparing top surface cooling, terminal cooling, and bottom surface cooling. [Figure 5] This is a schematic cross-sectional view corresponding to Figure 2 in the battery module of Modification Example 1. [Figure 6] This is a schematic diagram representing a battery. [Figure 7]Figure 6 shows an example of simulation results at the center temperature of the electrode group indicated by R, and is a figure showing an example of simulation results comparing top surface cooling, terminal cooling, and bottom surface cooling. [Figure 8] This figure shows an example of simulation results at the highest temperature of the battery group, and also shows an example of simulation results comparing top surface cooling, terminal cooling, and bottom surface cooling. [Figure 9] This is a schematic cross-sectional view corresponding to Figure 2 in another modified example of a battery module. [Figure 10] This is a schematic cross-sectional view corresponding to Figure 2 in a battery module of another modified example 3. [Figure 11] This is a schematic cross-sectional view corresponding to Figure 2 in a battery module of further modification 4. [Figure 12] This is a schematic cross-sectional view corresponding to Figure 2 in Modification 1 of the cooling plate. [Figure 13] This is a schematic cross-sectional view corresponding to Figure 2 in a modified example of the cooling plate. [Figure 14] Figure 14(A) is a schematic cross-sectional view corresponding to Figure 2 in Modification 3 of the cooling plate. Figure 14(B) is a schematic cross-sectional view showing a structure in which the passage in Figure 14(A) has been modified. [Figure 15] This is a schematic cross-sectional view corresponding to Figure 2 in a battery module of an additional modification. [Figure 16] This is a perspective view of the battery module according to Embodiment 2. [Figure 17] Figure 17(A) is a perspective view of the battery from the first side. Figure 17(B) is a perspective view of the battery from the second side. [Figure 18] This is a schematic cross-sectional view showing the internal structure of a battery. [Figure 19] Figures 19(A) and 19(B) are schematic diagrams showing how the electrode expands. [Figure 20] Figures 20(A) and 20(B) are schematic diagrams showing how gas is ejected from a battery. [Figure 21]Fig. 21(A) is a cross-sectional view schematically showing the internal structure of a battery according to Modification 1 of Embodiment 2. Fig. 21(B) is a cross-sectional view schematically showing the internal structure of a battery according to Modification 2 of Embodiment 2. Fig. 21(C) is a cross-sectional view schematically showing the internal structure of a battery according to Modification 3 of Embodiment 2. [Figure 22] Figs. 22(A) and 22(B) are cross-sectional views schematically showing the internal structure of a battery according to Modification 4 of Embodiment 2. [Figure 23] It is a cross-sectional view schematically showing the internal structure of a battery according to Embodiment 3. [Figure 24] Fig. 24(A) is a cross-sectional view schematically showing the internal structure of a battery according to Embodiment 4. Fig. 24(B) is a schematic view of an electrode assembly and a spacer as viewed from the valve portion side. Fig. 24(C) is an enlarged view of a region including the valve portion. [Figure 25] It is a schematic view showing an electrode assembly and a spacer in a battery according to Modification 5 of Embodiment 4 as viewed from the valve portion side. [Figure 26] It is a perspective view of a battery module according to Embodiment 5. [Figure 27] It is a perspective view of a battery. [Figure 28] Fig. 28(A) is a bottom view schematically showing a battery module. Fig. 28(B) is a cross-sectional view taken along line A-A in Fig. 28(A). [Figure 29] Fig. 29(A) is a cross-sectional view schematically showing a battery module according to Modification 1 of Embodiment 5. Fig. 29(B) is a cross-sectional view schematically showing a battery module according to Modification 2 of Embodiment 5. [Figure 30] It is a cross-sectional view schematically showing a battery module according to Embodiment 6. [Figure 31] Fig. 31(A) is a cross-sectional view schematically showing a battery module according to Modification 3 of Embodiment 6. Fig. 31(B) is a cross-sectional view schematically showing a battery module according to Modification 4 of Embodiment 6. [Figure 32] It is a cross-sectional view schematically showing a battery module according to Embodiment 7. [Figure 33]Figure 33(A) is a schematic cross-sectional view showing a battery module according to modification 5 of Embodiment 7. Figure 33(B) is a schematic cross-sectional view showing a battery module according to modification 6 of Embodiment 7. [Figure 34] This is a schematic cross-sectional view showing a battery module according to Embodiment 8. [Figure 35] This is a schematic cross-sectional view showing a battery module according to a modified example 7 of Embodiment 8. [Figure 36] This is a schematic cross-sectional view showing a battery module according to Embodiment 9. [Figure 37] This is a schematic cross-sectional view showing a battery module according to a modified example 8 of Embodiment 9. [Figure 38] This is a perspective view of the battery module according to Embodiment 10. [Figure 39] This is a perspective view of a battery. [Figure 40] This is a cross-sectional view of a battery module. [Figure 41] This is a cross-sectional view showing a magnified view of the area including the output terminals of the battery module. [Figure 42] This is a perspective view of the battery module according to Embodiment 11. [Figure 43] This is a schematic cross-sectional view showing a battery module according to Embodiment 12. [Figure 44] This is a schematic cross-sectional view showing a battery module according to Embodiment 13. [Modes for carrying out the invention]

[0009] The embodiments relating to this disclosure will be described in detail below with reference to the accompanying drawings. The following description of this disclosure will be based on preferred embodiments with reference to the drawings. The embodiments are illustrative and not limiting to the invention. Therefore, not all features or combinations thereof described in the embodiments are necessarily essential to the invention. In cases where multiple embodiments or modifications are included below, it is intended from the outset that new embodiments may be constructed by appropriately combining their characteristic parts. In the following drawings, the same elements (configurations) are denoted by the same reference numerals, and redundant explanations are omitted. In addition, the following figures are schematic diagrams, and the dimensional ratios of length, width, and height of each component do not match between different figures. Redundant explanations are omitted as appropriate. In addition, when terms such as "first," "second," etc. are used in this specification or claims, unless otherwise specified, these terms do not indicate any order or importance, but are used to distinguish one configuration from another. In addition, some components that are not important for explaining the embodiments may be omitted in each drawing.

[0010] (Embodiment 1) Figure 1 is a schematic perspective view of a part of the battery pack 1 according to this embodiment 1, viewed from the bottom. The lower part of the side wall 12 of the pack case 10 and the bottom of the pack case are omitted from the illustration, and the internal structure of the lower part of the battery pack 1 is visible. In order to explain the structure of the battery pack 1 in an easy-to-understand manner, in Figure 1, structures that become invisible due to the presence of the cooling plate 50, which will be described below, are shown with dotted lines. Also, in the embodiment shown in Figure 1, the output terminals 42 and 43 of the battery 31 are located on the lower side in the vertical direction. Therefore, in the description of this embodiment, the upper side is the opposite side from the terminal formation side in the Z direction of the battery 31, and the lower side is the electrode terminal formation side in the Z direction of the battery 31. In the following description and drawings of this embodiment, the X direction is the stacking direction in which the multiple batteries 31 are stacked in the battery group 21, the Y direction is the direction in which the multiple battery groups 21 are arranged, and the Z direction is the height direction of the battery 31. The X, Y, and Z directions are orthogonal to each other.

[0011] As shown in Figure 1, the battery pack 1 comprises a pack case 10, a plurality of battery modules 20, and a cooling plate 50. The pack case 10 includes a main body 11, a lid (not shown) that forms the bottom, and a plurality of screws (not shown). The main body 11 and the lid are made of metal such as aluminum or iron, or resin. The main body 11 is a box-shaped member having a substantially rectangular parallelepiped recess, the recess having a rectangular opening only on the lower side in the Z direction. Although not shown, the lid is a plate-shaped member with a rectangular shape in plan view. The main body 11 has an end face (not shown) on the lower side in the Z direction. Screw holes (not shown) are provided at predetermined intervals on the end face and the lid at positions that overlap each other when viewed from the Z direction, and there is a one-to-one correspondence between the screw holes on the end face and the screw holes on the lid.

[0012] The main body 11 is positioned with its opening facing upwards in the vertical direction, and each battery module 20, which will be described in detail later, is arranged so that the positive and negative output terminals 42 and 43 of the battery 31 are facing upwards. The cooling plate 50 is then placed on top of the cooling plate 50 so that it is in contact with the busbars 40 of the battery modules 20. Next, screws are tightened into the corresponding end faces and screw holes in the lid. Tightening these screws fixes the lid (bottom) to the main body 11, completing the battery pack 1. The battery pack 1 has a roughly rectangular parallelepiped shape. Finally, the battery pack 1 is turned over and fixed in place so that the lid faces downwards in the vertical direction, completing the installation of the battery pack 1.

[0013] Multiple battery modules 20 are arranged adjacent to each other in the recess of the pack case 10 in the Y direction. The area of ​​multiple battery modules 20 arranged adjacent to each other in the Y direction in a plan view is slightly smaller than the area of ​​the recess in a plan view. As a result, when the multiple battery modules 20 are housed in the recess, each battery module 20 is positioned in the X and Y directions within the recess.

[0014] The battery module 20 comprises a battery group 21, a first side-binding bar 22, a second side-binding bar 23, a pair of end plates 24, and a plurality of bus bars 40. In this embodiment, the pair of end plates 24 correspond to a pair of wall portions 12a extending in the Y direction in the main body portion 11 of the pack case 10. However, the configuration is not limited to this, and the pair of end plates may be members provided separately from the pair of wall portions.

[0015] The battery group 21 includes a plurality of substantially rectangular parallelepiped batteries (hereinafter referred to as batteries) 31 and a plurality of inter-battery separators 32. The batteries 31 are composed of rechargeable secondary batteries such as lithium-ion batteries, nickel-metal hydride batteries, and nickel-cadmium batteries, and have positive electrode output terminals 42 and negative electrode output terminals 43 that protrude downward in the Z direction from the same substantially planar first surface 45 (Figure 2). More specifically, each battery 31 comprises an electrode body 61 (see Figure 2), an outer casing 62 (see Figure 2) that houses the electrode body 61, a lid 63 (see Figure 2) that seals the opening of the outer casing 62, and positive electrode output terminals 42 and negative electrode output terminals 43 that are inserted through a pair of through holes provided in the lid 63, insulated from the lid 63, and electrically connected to the electrode body 61. Here, the outer casing 62 and the lid 63 constitute the housing. Parts of the output terminals 42 and 43 are exposed into the outer casing 62 from the lid 63. Multiple batteries 31 contained in the battery module 20 are arranged in a line in the X direction such that their output terminals 42 and 43 are alternately positioned when viewed from the X direction. The battery separator 32 is placed between two adjacent batteries 31 in the X direction. The main surface of each battery 31 is covered with an insulating sheet such as a shrink tube. The battery separator 32 is a sheet-like member and is made of an insulating material such as resin. The battery separator 32 is provided to ensure reliable insulation between two adjacent batteries 31 in the X direction.

[0016] In this embodiment, multiple batteries 31 included in the battery module 20 are connected in series by a busbar 40. Specifically, the busbar 40 is a plate-shaped member containing a conductive material. The busbar 40 is made of metal or the like. Each busbar 40 extends in the X direction. With respect to each battery 31, one of the positive output terminal 42 and the negative output terminal 43 is connected to the busbar 40. Specifically, in each battery 31, the output terminal 42 is connected to the busbar 40, and the output terminal 43 is connected to a busbar 40 different from the busbar 40 to which the output terminal 42 is connected. Each busbar 40 electrically connects the output terminal 42 of one battery 31 to the output terminal 43 of the other battery 31 of two adjacent batteries 31 in the X direction. The busbar 40 has, for example, two through holes formed in the thickness direction. These two through holes are spaced apart and arranged side by side in the X direction.

[0017] With the batteries 31 and the battery separator 32 in close contact, the output terminal 42 of one battery 31 is inserted through one through-hole of the busbar 40, and the output terminal 43 of the other battery 31 is inserted through the other through-hole of the busbar 40. The two adjacent batteries 31 are connected in series by welding these output terminals 42 and 43 to the inner surfaces of the through-holes of the busbar 40.

[0018] Each of the first and second side-bind bars 22 and 23 is a plate member or rectangular tube member made of a metal such as aluminum, iron, or stainless steel, and extends in the X direction. The dimensions of each of the first and second side-bind bars 22 and 23 in the X direction are slightly longer than the dimensions of the battery group 21 in the X direction. The first side-bind bar 22 restrains one end of the battery group 21 in the Y direction, and the second side-bind bar 23 restrains the other end of the battery group 21 in the Y direction. Each end plate 24 is also a plate member made of a metal such as aluminum or iron, and extends in the Y direction. An end plate 24 located on one side in the X direction restrains one side of the battery group 21 in the X direction, and an end plate 24 located on the other side in the X direction restrains the other side of the battery group 21 in the X direction. Furthermore, the first and second side bind bars 22 and 23 are not limited to metal materials; if weight reduction is prioritized over heat dissipation, they may be made of plastic materials such as CFRP (carbon fiber reinforced plastic).

[0019] The first and second side bind bars 22 and 23 are each provided with screw holes 29 at the lid-side ends of both end faces in the X direction for fixing end plates, and these screw holes 29 extend in the X direction. In addition, each of the pair of end plates 24 is provided with a through hole (screw hole) extending in the X direction. The battery module 20 also further includes an end separator 26, a first side separator 27, and a second side separator 28. The end separator 26, the first side separator 27, and the second side separator 28 are each sheet-like members made of an insulating material such as resin. The end separator 26 is positioned between one end of the battery group 21 in the X direction and the end plate 24 located on one side, and between the other end of the battery group 21 in the X direction and the end plate 24 located on the other side. On the other hand, the first and second side separators 27 and 28 extend in the X direction. The X-direction lengths of the first and second side separators 27 and 28 are approximately equal to the sum of the X-direction length of the battery group 21 and twice the X-direction length (thickness) of the end separator 26.

[0020] The first side separator 27 is positioned between one end of the battery group 21 in the Y direction and the first side bind bar 22. The second side separator 28 is positioned between the other end of the battery group 21 in the Y direction and the second side bind bar 23. The end separator 26 is positioned between both ends of the battery group 21 in the X direction and the pair of end plates 24. In this state, screws are inserted from the outside of the end plate 24 in the X direction into the through holes in the end plate 24 and the screw holes in the first and second side bind bars 22 and 23, and then tightened. This tightening fixes the battery group 21, the first and second side bind bars 22 and 23, the pair of end plates 24, the pair of end separators, and the first and second side separators 27 and 28, thus forming the battery module 20. With respect to each battery group 21, one side of each battery 31 in the Y direction is located substantially on the same plane due to constraints from the first side bind bar 22, and the other side of each battery 31 in the Y direction is located substantially on the same plane due to constraints from the second side bind bar 23.

[0021] Alternatively, the battery module 20 may be constructed by pressing a pair of end plates 24 from both sides with a press machine (not shown) to compress the battery group 21 with the end plates 24, and then screwing the pair of end plates 24 to the first and second side bind bars 22 and 23. In the embodiment shown in Figure 1, for example, in two adjacent battery groups 21 in the Y direction, one side bind bar 38 is interposed between the two battery groups. This side bind bar 38 restrains the side of one electrode group 21 facing the other electrode group 21, and the side of the other electrode group 21 facing the first electrode group 21. Alternatively, one side bind bar may be provided on each of the two adjacent battery groups, on the sides facing each other.

[0022] Furthermore, in the embodiment shown in Figure 1, for multiple battery modules 20 arranged in the Y direction, one end plate 24 constrains one end of the battery group 21 of each battery module 20 in the X direction, and the other end plate 24 constrains the other end of the battery group in the X direction. However, the end plates in this disclosure are not limited to the above configuration. For example, for each battery module, separate first and second end plates may be provided to constrain only both ends of the battery group of that battery module in the X direction. Note that, as in this embodiment, when multiple battery modules 20 are fixed with a single end plate 24, it becomes easier to connect multiple battery modules 20 arranged parallel to the Y direction in parallel by embedding and fixing the busbars extending in the Y direction to the end plate 24.

[0023] Furthermore, the end separator 26 may be elastic. In this case, even if there is a change in the dimensional gap between the battery 31 at the end in the X direction and at least one of the end plates 24 on one side, the end separator 26 can easily fill the gap between the battery 31 at the end in the X direction and at least one of the end plates 24 on one side. Thus, the battery group 21 can be arranged in close contact in the X direction.

[0024] Continuing with the reference to Figure 1, the cooling plate 50 is made of a metal such as aluminum or an aluminum alloy. The cooling plate 50 includes a flat plate portion 50a that is positioned below the battery module 20. The flat plate portion 50a has a shape that corresponds to the rectangular parallelepiped space that is created inside the pack case 10 below the lower surface of the busbar 40 and above the upper surface of the lid when multiple battery modules 20 are placed inside the internal chamber of the pack case 10. As a result, when the lid is fixed to the main body 11, the cooling plate 50 is positioned relative to the pack case 10 and is thermally connected to both the busbar 40 connected to the output terminal 42 of each battery 31 and the busbar 40 connected to the output terminal 43.

[0025] The cooling plate 50 has multiple passages 51 through which the coolant flows. The multiple passages 51 are spaced apart from each other in the Y direction. Each passage 51 extends in the X direction. Downstream of the multiple passages 51, the cooling plate 50 has a confluence section (not shown) where the coolant flows out of each passage 51 merge. Upstream of the multiple passages 51, there is a branching section (not shown) through which the coolant flows into each passage 51. Although not shown, a pair of wall sections 12a extending in the Y direction in the pack case 10 have coolant through-holes at positions overlapping the confluence section and the branching section, respectively. Supply piping (not shown) and return piping (not shown) are inserted through these coolant through-holes. Coolant such as water is sent from the discharge port of a pump (not shown) to the branching section via the supply piping (not shown). The coolant then flows through the multiple passages 51 and the confluence section, and then from the confluence section to the pump's suction port via the return piping (not shown). In this way, by circulating the coolant, the cooling plate 50 is cooled by the coolant, the busbar 40 is cooled by the cooling plate 50, and consequently, each battery 31 is cooled by the busbar 40. In addition, in the battery module of this disclosure, the coolant penetration holes may be provided in locations other than the pair of wall portions 12a.

[0026] Figure 2 is a schematic cross-sectional view of the line AA in Figure 1, and is a schematic cross-sectional view representing a part of the battery module 20 and the cooling plate 50. As shown in Figure 2, the busbar 40 of the battery module 20 has a flat metal part 40a as the main body and a flat insulating part 40b that has insulating properties. The metal part 40a contacts the lower surfaces 42a and 43a of the terminals 42 and 43 and is electrically connected to the lower surfaces 42a and 43a. The insulating part 40b is provided to cover the lower surface of the metal part 40a and is formed by coating the lower surface of the metal part 40a with an insulating material such as a silicon-based insulating resin. The insulating part 40b is not limited to a silicon-based insulating resin and may be made of any insulating material. However, it is preferable that the insulating part 40b is made of an insulating material with a thermal conductivity of 0.1W or more, more preferably an insulating material with a thermal conductivity of 1W or more, and most preferably an insulating material with a thermal conductivity of 2W or more.

[0027] As shown in Figures 1 and 2, the cooling plate 50 has a first surface contact portion 50b in addition to the flat plate portion 50a described above. As described above, the flat plate portion 50a is located on the underside of the battery module 20, and the first surface contact portion 50b extends upward from the portion located between the output terminals 42 and 43 on the upper surface of the flat plate portion 50a. The battery 31 has a first surface 45 (outer surface of the cover 63) which is substantially flat, and the output terminals 42 and 43 protrude downward in the Z direction from the first surface 45. The first surface contact portion 50b has a flat plate shape. The upper surface of the first surface contact portion 50b is in contact with the first surface 45, and as a result, the first surface 45 is efficiently cooled by the first surface contact portion 50b of the cooling plate 50, and consequently, the battery 31 is efficiently cooled by the first surface contact portion 50b.

[0028] Figures 3 and 4 show an example of simulation results indicating the degree of cooling of the battery 31, and are diagrams showing an example of simulation results comparing top surface cooling, terminal cooling, and bottom surface cooling. In detail, top surface cooling is the cooling using the flat plate portion 50a and the first surface contact portion 50b as described above. Terminal cooling is the cooling using a flat cooling plate 150, with the first surface contact portion 50b omitted, as shown in Figure 5, which is a schematic cross-sectional view corresponding to Figure 2 in the modified battery module 120, compared to the above embodiment. In other words, terminal cooling is achieved by contacting only the busbar 40 with the cooling plate 150 without contacting the first surface 45. Although not described in detail, bottom surface cooling is the cooling by contacting a flat cooling plate to the surface 48 (see Figure 5) opposite to the first surface 45 in the Z direction, with the battery 31 positioned so that the first surface 45 is on the upper side.

[0029] The battery 31 has a current interruption device (CID) on the terminals 42 and 43 in the Z direction inside. Figure 3 is a graph showing the simulation results of the temperature of the current interruption device (CID), and in the roughly rectangular battery 31 shown in Figure 6, it is a graph showing the simulation results of the temperature at the position indicated by P inside the battery 31. Figure 4 is a graph showing the simulation results of the battery top surface temperature, and in the battery 31 shown in Figure 6, it is a graph showing the simulation results of the temperature at the position indicated by Q.

[0030] In Figures 3, 4, and Figures 7 and 8 (which will be explained later), the following conditions hold: T8>T7>T6>T5>T4>T3>T2>T1>0, Tk+1-Tk=C1(constant)[°C](k is an integer between 1 and 7), t4>t3>t2>t1>0, and tl+1-tl=C2(constant)[sec](l is an integer between 1 and 3). In these figures, the dotted lines represent the simulation results for terminal cooling, the solid lines represent the simulation results for top surface cooling, and the dashed lines represent the simulation results for bottom surface cooling.

[0031] According to the simulation results shown in Figure 3, the CID temperature is highest with bottom cooling, lower with terminal cooling than with bottom cooling, and lowest with top cooling. Therefore, by performing cooling by bringing the cooling plate 150 (see Figure 5) into contact with the busbar 40, the terminal side structure of the internal structure of the battery 31 can be efficiently cooled. Furthermore, by performing cooling by bringing the cooling plate 50 (see Figure 2) into contact with the first surface 45 in addition to the busbar 40, the terminal side structure of the internal structure of the battery 31 can be cooled even more effectively. Also, as shown in Figure 4, by performing top cooling, the top surface temperature of the battery 31 can be lowered in addition to the CID temperature, and the entire battery 31 can be effectively cooled.

[0032] Figure 7 shows the simulation results for the center temperature of the electrode group indicated by R in Figure 6, and Figure 8 shows the simulation results for the maximum temperature of the battery group. These simulation results show that top cooling, like bottom cooling, can achieve the same effect on the center temperature of the electrode group and the maximum temperature of the battery group as bottom cooling.

[0033] As described above, the battery module 20 comprises a plurality of batteries (secondary batteries) 31, one or more busbars 40 that electrically connect the plurality of batteries 31, and a cooling plate 50 that has one or more passages 51 through which a coolant flows and is thermally connected to the busbars 40. Each of the plurality of batteries 31 comprises an electrode body 61, an outer casing 62 that houses the electrode body 61, a lid 63 that seals the opening of the outer casing 62, and a pair of output terminals 42, 43 that are inserted through a pair of through holes provided in the lid 63, insulated from the lid 63, and electrically connected to the electrode body 61. One of the pair of output terminals 42, 43 is connected to the busbars 40.

[0034] Therefore, the cooling plate 50 can be used to efficiently cool the busbar 40, terminals 42 and 43, and the upper part of the internal structure of the battery 31, and consequently, to efficiently cool the inside of the battery 31.

[0035] Furthermore, since the internal structure of the battery can be efficiently cooled by the cooling plate 50, there is no need to increase the heat capacity of the busbar 40 in order to cool the internal structure of the battery 31. Therefore, it is easier to miniaturize the busbar and make the battery module 20 more compact.

[0036] Furthermore, the busbar 40 may also include an insulating portion 40b made of a metal portion 40a and an insulating material that insulates the cooling plate 50 from the metal portion 40a.

[0037] With this configuration, the cooling plate 50 can be reliably insulated from the metal part 40a that makes electrical connections between the batteries 31 in the busbar 40. Therefore, short circuits between the batteries 31 can be reliably prevented.

[0038] Furthermore, the cooling plate 50 may include a first surface contact portion 50b that contacts the portion between the positive terminal 42 and the negative terminal 43 on the first surface 45.

[0039] With this configuration, the cooling plate 50 contacts the area between the positive output terminal 42 and the negative output terminal 43 on the first surface 45, in addition to the bus bar 40. This allows for efficient cooling of the terminals 42 and 43 in the Z direction of the battery 31, as well as the internal structure of the battery 31, thus enabling more effective cooling of the entire battery 31.

[0040] Furthermore, the cooling plate 50 may have a flat plate portion 50a positioned vertically below the output terminals 42 and 43.

[0041] With this configuration, the flat portion 50a of the cooling plate 50 is positioned vertically below the output terminals 42 and 43, allowing the flat portion 50a to be made larger and the cooling effect of the cooling plate 50 to be significantly enhanced. In addition, the flat portion 50a can stably support the battery 31, thereby stabilizing the orientation of the battery module 20. Furthermore, "the flat portion 50a is positioned vertically below" can be rephrased as being positioned so that gravity acts from the battery towards the flat portion.

[0042] Furthermore, the cooling plate 50 may be thermally connected to both the busbar 40 connected to the positive output terminal 42 and the busbar 40 connected to the negative output terminal 43 of each battery 31.

[0043] With this configuration, the cooling plate 50 can cool both the output terminals 42 and 43 of each battery 31, allowing for efficient cooling of the internal structure of the battery 31.

[0044] Furthermore, the battery pack 1 may comprise multiple battery modules 20. Each battery module 20 may also have a battery group 21 containing multiple batteries 31 arranged in a row. The multiple battery groups 21 included in the multiple battery modules 20 may be arranged so that the direction in which the batteries 31 are arranged in each battery group 21 is substantially parallel. The multiple cooling plates 50 included in the multiple battery modules 20 may also be integrally configured.

[0045] With this configuration, each busbar 40 of multiple battery modules 20 can be cooled by a single, integrated, indivisible cooling plate 50. Therefore, the internal structure of each battery module 20 can be efficiently cooled, and the battery pack 1 can be easily assembled.

[0046] This disclosure is not limited to the embodiments and their modifications, and various improvements and modifications are possible within the scope of the claims of this application and their equivalents.

[0047] For example, in the above embodiment, the case in which the insulating portion 40b is provided on the busbar 40 was described. However, the insulating portion may be provided on a cooling plate instead of a busbar. Specifically, the cooling plate may have a metal main body and an insulating portion made of an insulating material that insulates the main body from the busbar. In this case, the insulating portion may be provided on the entire surface of the busbar-side surface of the cooling plate, or it may be provided only on the portion of the busbar-side surface of the cooling plate that overlaps with the busbar when viewed from the Z direction. Alternatively, the cooling plate may be made of an insulating resin. Furthermore, even when the insulating portion is provided on the cooling plate or when the cooling plate is made of an insulating material, the insulating portion or insulating material on the cooling plate may be made of an insulating material with a thermal conductivity of 0.1W or more. In this case, the insulating material may have a thermal conductivity of 1W or more, or it may be made of an insulating material with a thermal conductivity of 2W or more.

[0048] Furthermore, the case in which the cooling plate 50 is not positioned relative to the bus bar 40 has been described. However, as shown in Figure 9, i.e., a schematic cross-sectional view corresponding to Figure 2 in another modified battery module 220, at least one bus bar 240 may have a projection 241 as a first locking part projecting downward in the Z direction, and the cooling plate 250 may have a hole 253 as a second locking part, and the projection 241 may be locked into the hole 253. Alternatively, at least one bus bar may have a hole, and the cooling plate may have a projection that engages with that hole.

[0049] Alternatively, through holes may be provided in both the busbar and the cooling plate, and a shaft portion having a male thread may be provided on the output terminal of the battery, protruding in the height direction. After inserting the shaft portion of the output terminal through the through holes in the busbar and the cooling plate, the busbar and cooling plate may be fixed to the battery terminal by tightening a nut on the protruding portion of the shaft portion that extends from the cooling plate. Alternatively, the output terminal of the battery may have a shaft portion that extends in the height direction, and both the cooling plate and the busbar may have U-shaped grooves. The cooling plate and busbar may then be fixed to the battery output terminal by press-fitting the shaft portion into each U-shaped groove.

[0050] More generally, with respect to the battery module, at least one busbar may have one or more first locking parts, and the cooling plate may have one or more second locking parts that lock onto the first locking parts. According to these modifications, the cooling plate can be positioned relative to the battery module. Therefore, it is easier to cool the battery module with the cooling plate and to achieve efficient cooling of the battery. Furthermore, positioning is made even easier if two or more second locking parts are provided on a single cooling plate.

[0051] Furthermore, the case in which the battery 31 has its terminals 42 and 43 facing vertically downward has been described. However, as shown in Figure 10, a schematic cross-sectional view corresponding to Figure 2 in another modified battery module 320, the substantially rectangular parallelepiped battery 31 may be placed in the battery pack with its output terminals 42 and 43 facing vertically upward. The cooling plate 350 may have a flat plate portion 350a located above the busbar 340, and the lower surface of the flat plate portion 350a may be in contact with the upper surface of the busbar 340.

[0052] Furthermore, as shown in Figure 11, a schematic cross-sectional view corresponding to Figure 2 in a further modified battery module 420, the secondary battery may be a substantially rectangular parallelepiped battery 31, and the battery 31 may have output terminals 42, 43 protruding to the outside from the same substantially flat first surface 45. Also, the cooling plate 450 may include a flat plate portion 452 that contacts a busbar 440 that electrically connects the terminals of the multiple batteries 31, and an orthogonal surface contact portion 455 that contacts an orthogonal surface 46 that is substantially perpendicular to the first surface 45 in the battery 31. In the modified example shown in Figure 11, the orthogonal surface 46 is located on the lower side in the vertical direction and extends in a direction perpendicular to the height direction. However, the orthogonal surface 46 that is substantially perpendicular to the first surface 45 may extend in the height direction in the operating state, or it may be located on the upper side in the vertical direction and extend in a direction perpendicular to the height direction.

[0053] According to the above modified example, the cooling plate 450 can effectively cool the internal structure of the battery 31 with the flat plate portion 452 that contacts the busbar 440, and the orthogonal surface 46 of the battery 31 can be cooled with the orthogonal surface contact portion 455 of the cooling plate 450. Therefore, the battery 31 can be cooled more efficiently. The battery module of this disclosure may also be provided with a cooling plate for cooling the battery casing in addition to the cooling plate for cooling the busbar.

[0054] Furthermore, the case in which the cooling plate 50 is placed inside the pack case 10 of the battery pack 1 has been described. However, the cooling plate may also constitute the lid or bottom of the pack case.

[0055] Furthermore, with reference to Figure 1, the case in which the coolant passage 51 extends in the X direction within the cooling plate 50 has been explained. However, the coolant passage may also extend in the Y direction within the cooling plate.

[0056] Furthermore, the case in which the cooling plate 50 is shared by multiple battery modules 20 and the battery pack 1 has only one cooling plate 50 has been described. However, the battery pack may have multiple battery modules and multiple cooling plates, and each cooling plate may cool only one battery module.

[0057] Furthermore, the case in which all batteries 31 included in the battery module 20 are connected in series has been described. However, all batteries included in the battery module may be connected in parallel. Alternatively, the battery module may include two or more batteries connected in series and two or more batteries connected in parallel.

[0058] Furthermore, the case in which the cooling plate 50 is thermally connected to both the busbar 40 connected to the positive terminal 42 and the busbar 40 connected to the negative terminal 43 of each battery 31 has been described. However, the cooling plate does not necessarily have to be thermally connected to both the busbar connected to the positive output terminal and the busbar connected to the negative output terminal of each battery.

[0059] Furthermore, the case in which the cooling plate 50 is insulated from the busbars 40 has been described. However, the cooling plate may only be in contact with busbars that are permitted to be conductive, and the cooling plate does not need to be insulated from the busbars.

[0060] Figures 12, 13, and 14 are schematic cross-sectional diagrams corresponding to Figure 2, showing modified examples 1, 2, and 3 of the cooling plate.

[0061] As shown in Figure 12, the cooling plate 550 has a first main surface 551 facing the multiple batteries 31 and a second main surface 552 located on the opposite side of the first main surface 551. On the first main surface 551, the area where the contact surface of the first surface contact portion 553 is formed protrudes toward the multiple batteries 31, and on the second main surface 552, at least a portion of the area overlapping with the contact surface of the first surface contact portion 553 may be recessed to form a recess 554. This configuration makes it possible to reduce the size of the cooling plate 550 while reducing the distance between the first surface (for example, the surface of the lid 63) and the contact surface of the first surface contact portion 553.

[0062] Furthermore, as shown in Figure 13, in the cooling plate 650, the first surface contact portion 653 may be thicker than the rest, and the passage 654 in the first surface contact portion 653 may be larger in the thickness direction of the cooling plate 650 (in other words, in the direction in which the multiple batteries 31 and the cooling plate 650 face each other) than the passage 655 of the rest. This configuration makes it easier to increase the cross-sectional area of ​​the passage 654 in the first surface contact portion 653 perpendicular to the direction in which the coolant flows. As a result, it becomes possible to transfer more heat to the coolant not only from the first surface contact portion 653 but also from the cooling plate 650. In addition, it becomes possible to reduce the pressure loss of the coolant flowing through the cooling plate 650.

[0063] Furthermore, as shown in Figures 14(A) and (B), the cooling plate 750 has two flat plate portions 756 facing the busbar 40 and a connecting portion 757 connecting the flat plate portions 756 and the first surface contact portion 753. This connecting portion 757 may be more flexible than the flat plate portions 756 and the first surface contact portion 753. With this configuration, the highly flexible connecting portion 757 makes it possible to thermally connect to multiple batteries 31 (or busbars 40) while absorbing tolerances (dimensional tolerances, assembly tolerances, etc.) in the multiple batteries 31 (or busbars 40). This connecting portion 757 may be provided by joining a separate member from the first surface contact portion 753 and the flat plate portion 756, or it may be provided by processing the portion of the cooling plate 750 that is integrated with the first surface contact portion 753 and the flat plate portion 756. In the cooling plate 750 shown in Figure 14(A), passages 758 are provided in each flat plate portion 756. In the cooling plate 750 shown in Figure 14(B), a first surface contact portion 753 and passages 759 are provided.

[0064] Figure 15 shows an additional modified battery module with a battery 31 and a cooling plate 850, and is a schematic cross-sectional view corresponding to Figure 2. The cooling plate 850 faces the first surface of the housing, such as the lid 63, and multiple heat transfer sheets 800 are provided between the cooling plate 850 and the first surface. The rigidity of the heat transfer sheet 800A interposed between the first surface contact portion 853 and the first surface may differ from that of the heat transfer sheet 800B interposed between the remaining part of the cooling plate 850 excluding the first surface contact portion 853 and the first surface. With this configuration, when connecting the cooling plate 850 to multiple batteries 31 (or busbars 40), the heat transfer sheets 800 absorb the height differences and tilt of each battery 31 that occur between the multiple batteries 31, allowing the cooling plate 850 to be connected to the multiple batteries 31 (or busbars 40). Specifically, the elastic modulus of the heat transfer sheet 800B covering the contact surface between each battery 31 and the output terminal 42 (or busbar 40) of the cooling plate 850 and the flat plate portion 856 may be higher than that of the heat transfer sheet 800A provided on the contact surface of the first surface contact portion with the first surface. This is because, by satisfying this relationship of relative elastic moduli, the tilt tolerance of the batteries tends to be larger than the height tolerance between the batteries, and the amount of tolerance to be absorbed tends to be larger.

[0065] Next, embodiments 2, 3, and 4 will be described.

[0066] In recent years, there has been a growing demand for higher capacity battery modules, and to meet this demand, battery capacity is being increased. As battery capacity increases, a large current flows through the busbars connecting the batteries. This increases the amount of heat generated in the busbars. When the amount of heat generated in the busbars increases, heat is transferred from the busbars to the batteries, causing the battery temperature to rise and potentially reducing the battery's power generation performance. One way to suppress the heat generated in the busbars is to place a cooling plate against them. However, in conventional batteries, the output terminals and the safety valve were located on the same side of the outer casing. Therefore, if a cooling plate is placed against the busbars, the area above the safety valve will be covered by the cooling plate. In this case, when gas is released from the safety valve, the gas accumulates between the cooling plate and the battery, making it easier for the battery contents to adhere to the output terminals. If the battery contents adhere to the output terminals, it can cause corrosion of the output terminals or short circuits between batteries, potentially reducing the reliability of the battery module. Therefore, there was room for improvement in conventional battery modules to enhance reliability.

[0067] The battery modules of Embodiments 2, 3, and 4 were developed in view of these circumstances, and their purpose is to provide technology for improving the reliability of battery modules.

[0068] In the battery modules of embodiments 2, 3, and 4, the housing of the battery has a valve portion arranged on a surface different from the first surface for releasing gas inside the housing.

[0069] The battery modules of embodiments 2, 3, and 4 can improve the reliability of the battery modules.

[0070] (Embodiment 2) Figure 16 is a perspective view of a battery module according to Embodiment 2. Figure 16 shows the cooling plate and busbars in a disassembled state. The battery module 2001 comprises an assembly 2002, a cooling plate 2004, and a plurality of busbars 2016. The assembly 2002 has a structure in which a plurality of batteries 2006 are assembled. The assembly 2002 of this embodiment takes the form of a battery group in which a plurality of flat batteries 2006 are stacked, that is, a battery stack. The assembly 2002 comprises a plurality of batteries 2006, a plurality of separators 2008, a pair of end plates 2010, and a pair of bind bars 2012.

[0071] Each battery 2006 is a rechargeable secondary battery, such as a lithium-ion battery, nickel-metal hydride battery, or nickel-cadmium battery. Battery 2006 is a so-called prismatic battery. Battery 2006 has a positive output terminal 2014 and a negative output terminal 2014 on the first surface 2020a of the housing 2020, which will be described later. Hereinafter, the positive output terminal 2014 will be referred to as the positive terminal 2014a, and the negative output terminal 2014 will be referred to as the negative terminal 2014b. Also, when it is not necessary to distinguish the polarity of the output terminals 2014, the positive terminal 2014a and the negative terminal 2014b will be collectively referred to as the output terminal 2014.

[0072] The first surface 2020a, on which a pair of output terminals 2014 are provided, is substantially rectangular in shape. The battery 2006 has a pair of long sides connected to the long side of the first surface 2020a, and a pair of short sides connected to the short side of this surface. The long sides are the surfaces of the battery 2006 with the largest area (main surface). Multiple batteries 2006 are arranged side by side at predetermined intervals such that the long sides of adjacent batteries 2006 face each other. In this embodiment, the direction in which the multiple batteries 2006 are arranged is defined as direction X.

[0073] The output terminals 2014 of each battery 2006 are arranged so that they face the same direction. Two adjacent batteries 2006 are stacked so that the positive terminal 2014a of one battery 2006 faces the negative terminal 2014b of the other battery 2006. The positive terminal 2014a and the negative terminal 2014b are electrically connected via a busbar 2016. Alternatively, the output terminals 2014 of adjacent batteries 2006 with the same polarity may be connected in parallel with a busbar 2016 to form a battery block, and these battery blocks may be connected in series.

[0074] The separator 2008, also called an insulating spacer, is made of, for example, an insulating resin. The separator 2008 is placed between two adjacent batteries 2006 to electrically insulate them. Furthermore, the separator 2008 is placed between a battery 2006 and an end plate 2010 to insulate them. The separator 2008 also extends in direction X and covers a portion of the battery 2006. This ensures a creepage distance between adjacent batteries 2006 or between a battery 2006 and an end plate 2010. Examples of resins that make up the separator 2008 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl® resin (modified PPE).

[0075] Multiple batteries 2006 and multiple separators 2008, arranged side by side, are sandwiched between a pair of end plates 2010. The pair of end plates 2010 are positioned adjacent to the batteries 2006 located at both ends in direction X, via the separators 2008. The end plates 2010 are made of, for example, metal plates. Screw holes (not shown) into which screws 2018 are screwed are provided on the surfaces of the end plates 2010 that face the long sides of the batteries 2006.

[0076] The pair of bind bars 2012 are elongated members with direction X as their longitudinal direction. The pair of bind bars 2012 are arranged facing each other in direction Y, which is perpendicular to direction X and parallel to the longitudinal direction of the first surface 2020a. Between the pair of bind bars 2012 are a plurality of batteries 2006, a plurality of separators 2008, and a pair of end plates 2010. Each bind bar 2012 has a rectangular planar portion 2012a extending parallel to the short side of the battery 2006, and four overhang portions 2012b protruding from each end of the planar portion 2012a toward the battery 2006. Two overhang portions 2012b that face each other in direction X are provided with through holes (not shown) through which screws 2018 are inserted. The planar portion 2012a is provided with an opening 12c that exposes the short side of the battery 2006.

[0077] Multiple batteries 2006 and multiple separators 2008 are arranged alternately and sandwiched in direction X by a pair of end plates 2010, and then sandwiched in direction Y by a pair of bind bars 2012. Each bind bar 2012 is positioned so that its through hole aligns with the screw hole in the end plate 2010. Then, a screw 2018 is inserted through the through hole and screwed into the screw hole. In this way, the multiple batteries 2006 are restrained by the engagement of the pair of bind bars 2012 with the pair of end plates 2010.

[0078] Multiple batteries 2006 are positioned in direction X by being clamped in direction X by a bind bar 2012. Furthermore, the first surface 2020a and the second surface 2020b (see Figure 17(B)) of each of the multiple batteries 2006 contact two opposing overhangs 2012b in direction Z, which is perpendicular to directions X and Y, via a separator 2008. This positions the multiple batteries 2006 in direction Z. For example, after this positioning is complete, a bus bar 2016 is attached to the output terminal 2014 of each battery 2006, electrically connecting the output terminals 2014 of the multiple batteries 2006.

[0079] The assembly 2002 has a cooling plate 2004 covering the side on which the output terminals 2014 protrude. The cooling plate 2004 is positioned to face the output terminals 2014 or the first surface 2020a across the busbars 2016, and is thermally, i.e., heat-exchangeably, connected to each busbar 2016. The main surface of the cooling plate 2004 is in contact with each busbar 2016. This cools each busbar 2016, and consequently each battery 2006. Between each busbar 2016 and the cooling plate 2004, a resin sheet or the like with good thermal conductivity may be interposed to further improve the heat exchange efficiency between them. Alternatively, a thermally conductive sheet may be interposed between the cooling plate 2004 and the surface of the battery 2006 facing the cooling plate 2004, for example, between the cooling plate 2004 and the surface between the two output terminals 2014 on the battery 2006.

[0080] The cooling plate 2004 is made of a material with high thermal conductivity, such as aluminum. The cooling plate 2004 may also have internal channels through which a coolant, such as water or ethylene glycol, flows. In other words, the cooling plate 2004 may be a flat, tubular shape. This allows for improved cooling efficiency of the busbar 2016 and the battery 2006. The cooling plate 2004 has insertion portions (not shown) at predetermined positions through which fastening members, such as screws, are inserted. The assembly 2002 and the cooling plate 2004 are fixed to each other by the fastening members being inserted into the insertion portions. The fastening members used to fix the assembly 2002 and the cooling plate 2004 may also be used to fix the cooling plate 2004 to the module case. Preferably, the fastening members are positioned so as not to overlap with the battery 2006 when viewed from the direction in which the assembly 2002 and the cooling plate 2004 are aligned. For example, the fastening members are connected to the end plate 2010 or the bind bar 2012.

[0081] Next, the structure of the battery 2006 will be described in detail. Figure 17(A) is a perspective view of the battery from the first side. Figure 17(B) is a perspective view of the battery from the second side. Figure 18 is a schematic cross-sectional view showing the internal structure of the battery. The battery 2006 comprises a housing 2020, an output terminal 2014, a valve portion 2022, an electrode body 2024, and a restraining portion 2026.

[0082] The housing 2020 has a flattened rectangular parallelepiped shape. The housing 2020 has a bottomed cylindrical outer container 2029 with a roughly rectangular opening 2021 formed therein, and the electrode body 2024 and electrolyte solution are housed inside the outer container 2029 through the opening 2021. The housing 2020 has a lid 2028 that closes the opening 2021. The lid 2028 is, for example, a rectangular plate. The lid 2028 and the outer container 2029 (including the lid 2028) are conductive materials, for example, metal. For example, the housing 2020 is made of aluminum, iron, stainless steel, etc. The lid 2028 and the opening 2021 are joined together, for example, by laser. The lid 2028 is provided with a positive electrode terminal 2014a near one end in the longitudinal direction and a negative electrode terminal 2014b near the other end. Therefore, the lid 2028 constitutes the first surface 2020a of the housing 2020. The lid 2028 and outer can 2029 may be made of resin.

[0083] The valve section 2022 is positioned on a surface of the housing 2020 that is different from the first surface 2020a. Therefore, the housing 2020 has a valve section-mounted surface where the valve section 2022 is positioned, and a valve section-non-mounted surface where the valve section 2022 is not positioned. The first surface 2020a is included in the valve section-non-mounted surface. In this embodiment, the valve section 2022 is positioned on the second surface 2020b, which is opposite the first surface 2020a. Therefore, the second surface 2020b is the valve section-mounted surface. Thus, the valve section-mounted surface is opposite the first surface 2020a.

[0084] The valve section 2022, also known as a safety valve, is a mechanism for releasing gas from inside the housing 2020. For example, the valve section 2022 is composed of a thin-walled section that is thinner than other parts and is provided on a part of the second surface 2020b, and a linear groove formed on the surface of this thin-walled section. In this configuration, when the internal pressure of the housing 2020 rises above a predetermined value, the thin-walled section ruptures starting from the groove, causing the valve section 2022 to open. As a result, gas inside the housing 2020 is released from the valve section 2022. Examples of gas inside the housing 2020 include carbon dioxide produced by the decomposition of the electrolyte. In addition, the gas released outside the housing 2020 may also include fine particles such as fragments of the battery structure. Note that the valve section 2022 is not limited to a configuration in which the surface of the housing 2020 on the side of the second surface 2020b that is exposed to the outside is recessed. For example, the surface facing the electrode body 2024 on the second surface 2020b may be formed by creating a recess.

[0085] Each of the pair of output terminals 2014 is electrically connected to the electrode body 2024 via a current collector 2032 located within the housing 2020. The current collector 2032 has a current collector plate 2034 and a tab portion 2036. Each of the pair of output terminals 2014 is inserted through a through hole 2038 formed in the lid 2028 and fixed to the current collector plate 2034. An insulating sealing member (not shown) is interposed between the output terminals 2014 and the current collector plate 2034 and the lid 2028.

[0086] The electrode body 2024 has a structure in which multiple electrode plates 2040 are stacked. Specifically, the electrode body 2024 has a structure in which positive electrode plates 2040a, which are positive electrode plates 2040, and negative electrode plates 2040b, which are negative electrode plates 2040, are stacked alternately. An electrode plate separator 2042 is interposed between adjacent positive electrode plates 2040a and negative electrode plates 2040b. Each electrode plate 2040 and the current collector plate 2034 are electrically connected via a tab portion 2036. Each positive electrode plate 2040a is connected to the current collector plate 2034 fixed to the positive electrode terminal 2014a, and each negative electrode plate 2040b is connected to the current collector plate 2034 fixed to the negative electrode terminal 2014b. The electrode plate separator 2042 is permeated with electrolyte. Therefore, if gas is generated due to the decomposition of the electrolyte, the electrode body 2024 may expand. The second surface 2020b, which is the valve arrangement surface, faces the end face parallel to the stacking direction (direction X in this embodiment) of the multiple positive electrode plates 2040a and multiple negative electrode plates 2040b in the electrode body 2024.

[0087] The restraining portion 2026 is a member that restrains the edge of the electrode body 2024. The restraining portion 2026 bundles together multiple positive electrode plates 2040a and multiple negative electrode plates 2040b. The restraining portion 2026 also bundles together multiple electrode plates 2040 and the electrode plate separator 2042. The restraining portion 2026 restrains the edge of the electrode body 2024 that faces the surface where the valve portion is not positioned. In the example shown in Figure 18, the second edge portion 2024b of the electrode body 2024 that faces the first surface 2020a, which is the surface where the valve portion is not positioned, is restrained by the restraining portion 2026, or more specifically, the second gripping portion 2046 which will be described later.

[0088] Furthermore, the first surface 2020a corresponds to the opposing surface that faces the second surface 2020b, which is the valve surface, among the surfaces where the valve is not positioned. Therefore, the second gripping portion 2046 of the restraining portion 2026 restrains the edge that is closer to the opposing surface than to the valve surface. More specifically, the second gripping portion 2046 of the restraining portion 2026 restrains the second edge 2024b that faces the opposing surface. The edge that is closer to the opposing surface than to the valve surface includes not only the edge that faces the opposing surface, but also the region of the edge that connects the edge that faces the valve surface and the edge that faces the opposing surface, which is closer to the opposing surface, for example, the region on the opposing surface side of the midpoint of the edge.

[0089] Furthermore, the electrode body 2024 has a first edge portion 2024a facing the valve portion arrangement surface and a second edge portion 2024b on the opposite side of the first edge portion 2024a. The restraining portion 2026 of this embodiment restrains the multiple electrode plates 2040 such that when the electrode body 2024 expands, the first edge portion 2024a on the valve portion 2022 side of the electrode body 2024 expands more than the second edge portion 2024b in the stacking direction of the electrode plates 2040.

[0090] The restraining portion 2026 has a first gripping portion 2044 that grips the first edge portion 2024a and a second gripping portion 2046 that grips the second edge portion 2024b. The first gripping portion 2044 and the second gripping portion 2046 are made of a resin having, for example, insulating properties and corrosion resistance to electrolytes. Specifically, polymer materials such as polyphenylene sulfide resin (PPS), polyimide resin, polyamide-imide resin, polyetheretherketone resin (PEEK), polyetherketoneketone resin (PEKK), and polyethersulfone resin (PES) can be preferably used. Alternatively, polymer materials such as polyolefin resins such as polypropylene (PP) and polyethylene (PE); fluororesins such as perfluoroalkoxyalkanes (PFA) and polytetrafluoroethylene (PTFE) may be used. Furthermore, the first gripping portion 2044 and the second gripping portion 2046 may be insulating adhesive tapes. Specifically, it may be polyethylene (PE), polypropylene (PP), or polyphenylene sulfide (PPS).

[0091] The first gripping portion 2044 has a flat plate portion 2044a and a pair of arm portions 2044b. The flat plate portion 2044a extends to the electrode plates 2040 located at both ends in the stacking direction (direction X in this embodiment) of the electrode plates 2040, and its main surface abuts against each electrode plate 2040. The pair of arm portions 2044b extend from both ends of the flat plate portion 2044a in the stacking direction of the electrode plates 2040 toward the second edge portion 2024b. The first gripping portion 2044 restrains the first edge portions 2024a of the multiple electrode plates 2040 in the stacking direction by the pair of arm portions 2044b. The first gripping portion 2044 is not limited to a configuration in which the flat plate portion 2044a covers the surface of the first edge portion 2024a that faces the second surface 2020b when restraining the first edge portion 2024a. For example, the flat plate portion 2044a may be positioned to cover the surface of the electrode body 2024 that faces the short side surface 2020c.

[0092] The second gripping portion 2046 has a flat plate portion 2046a and a pair of arm portions 2046b. The flat plate portion 2046a extends to the electrode plates 2040 located at both ends in the stacking direction of the electrode plates 2040, and its main surface abuts against each electrode plate 2040. The pair of arm portions 2046b extend from both ends of the flat plate portion 2046a in the stacking direction of the electrode plates 2040 toward the first edge portion 2024a. The second gripping portion 2046 restrains the second edge portions 2024b of the multiple electrode plates 2040 in the stacking direction by the pair of arm portions 2046b. Note that the second gripping portion 2046 is not limited to a configuration in which the flat plate portion 2046a covers the surface of the second edge portion 2024b that faces the first surface 2020a when restraining the second edge portion 2024b. For example, the flat plate portion 2046a may be positioned to cover the surface of the electrode body 2024 that faces the short side surface 2020c.

[0093] The first gripping portion 2044 deforms more than the second gripping portion 2046 when subjected to force in the stacking direction of the multiple positive electrode plates 2040a and multiple negative electrode plates 2040b. For example, the flat plate portion 2044a and arm portion 2044b of the first gripping portion 2044 are thinner than the flat plate portion 2046a and arm portion 2046b of the second gripping portion 2046. As a result, the first gripping portion 2044 has higher flexibility than the second gripping portion 2046. Therefore, the restraining force of the first gripping portion 2044 is smaller than that of the second gripping portion 2046. Consequently, gas is more likely to flow out from the first edge portion 2024a than from the second edge portion 2024b. Also, when enough gas is generated to cause the electrode body 2024 to swell, the first gripping portion 2044 deforms more than the second gripping portion 2046. Furthermore, by constructing the first gripping portion 2044 with a material that is more flexible than the material that constitutes the second gripping portion 2046, the amount of deformation of the first gripping portion 2044 can be made greater than the amount of deformation of the second gripping portion 2046.

[0094] The following methods are examples of how to attach the first gripping portion 2044 and the second gripping portion 2046 to the electrode body 2024. For example, if the flexibility of the flat portion of each gripping portion is low and the flexibility of the arm portion is high, the gripping portion can be attached to the electrode body 2024 by press-fitting the electrode body 2024 between the pair of arms. In order to facilitate the attachment of the gripping portion to the electrode body 2024, the opposing surfaces of the pair of arms, that is, the surfaces that contact the electrode body 2024, may be tapered so that the distance between them increases towards the tips of the arms. If the flexibility of the arms is low, similar to the flat portion, the electrode body 2024 can be restrained by the gripping portion by making the distance between the pair of arms smaller than the thickness of the electrode body 2024 in the stacking direction. Furthermore, if the first gripping portion 2044 and / or the second gripping portion 2046 are made of a material with little rigidity, such as adhesive tape, the gripping portion may be attached to the electrode body 2024 while applying tension to the adhesive tape when attaching it to the electrode body 2024.

[0095] Figures 19(A) and 19(B) are schematic diagrams showing how the electrode body expands. As shown in Figure 19(A), if gas is generated inside the electrode body 2024 due to the decomposition of the electrolyte, the electrode body 2024 may expand. When the electrode body 2024 expands, the first gripping portion 2044 and the second gripping portion 2046 are subjected to a force in the stacking direction of the electrode plate 2040, more specifically, a force in the direction that separates the pair of arms 2044b and 46b from each other. At this time, the first gripping portion 2044, which has lower rigidity than the second gripping portion 2046, can deform more than the second gripping portion 2046. Therefore, the first edge portion 2024a of the electrode body 2024 can expand more than the second edge portion 2024b.

[0096] Therefore, as shown in Figure 19(B), the gas G generated inside the electrode body 2024 can be ejected from the first edge 2024a side to the outside of the electrode body 2024. When the gas is ejected from the first edge 2024a, the electrode body 2024 can be displaced in a direction away from the valve portion 2022, using the ejection of the gas as a propulsion force. In this case, the electrode body 2024 can be pushed away from the valve portion 2022. Thus, a flow path can be secured for the gas inside the housing 2020 to reach the valve portion 2022.

[0097] Figures 20(A) and 20(B) are schematic diagrams showing how gas is ejected from a battery. As shown in Figure 20(A), for example, the battery 2006 is positioned so that its output terminal 2014 faces vertically downward and is placed on the cooling plate 2004. In this embodiment, the valve 2022 is located on the second surface 2020b, which is opposite to the first surface 2020a where the output terminal 2014 is located. Therefore, the valve 2022 faces vertically upward. As a result, the gas G inside the battery 2006 is released from the valve 2022 toward the opposite side of the output terminal 2014.

[0098] Furthermore, the location where the valve portion 2022 is provided, i.e., the surface on which the valve portion is located, is not limited to the second surface 2020b facing the first surface 2020a on which the output terminal 2014 is located. For example, as shown in Figure 20(B), the valve portion 2022 may be located on the short side 2020c of the battery 2006. In this case, the gas G inside the battery 2006 is released from the valve portion 2022 toward the side of the battery 2006.

[0099] As described above, the battery module 2001 of this embodiment comprises an assembly 2002 of a plurality of batteries 2006, a busbar 2016, and a cooling plate 2004. Each battery 2006 has a housing 2020, a pair of output terminals 2014 located on the first surface 2020a of the housing 2020, and a valve portion 2022 located on a surface different from the first surface 2020a of the housing 2020 for releasing gas inside the housing 2020. The busbar 2016 electrically connects the output terminals 2014 of the plurality of batteries 2006 to each other. The cooling plate 2004 is thermally connected to the busbar 2016 and faces the first surface 2020a. By connecting the cooling plate 2004 to the busbar 2016 in this way, the busbar 2016 can be efficiently cooled. This makes it possible to increase the capacity of the battery 2006 and the battery module 2001 without increasing the size or complexity of the busbars, thereby increasing the heat capacity of the busbars.

[0100] Furthermore, the heat generated in the busbar 2016 can be transferred to the battery 2006, preventing its temperature from rising. In addition, the cooling plate 2004 can also cool the output terminal 2014 and electrode body 2024 via the busbar 2016. As a result, the battery 2006 can be cooled efficiently, and the decrease in the power generation performance of the battery module 2001 can be suppressed. Moreover, since the heat dissipation structure of the battery module 2001 other than the cooling plate 2004 can be omitted or reduced, the battery module 2001 can be made smaller and less expensive.

[0101] Furthermore, in this embodiment, the battery 2006 has its output terminal 2014 and valve section 2022 located on different sides of the housing 2020. Therefore, even when the cooling plate 2004 is connected to the busbar 2016, the valve section 2022 is not covered by the cooling plate 2004. Thus, it is possible to prevent the gas G released from the valve section 2022 from accumulating in the space between the housing 2020 and the cooling plate 2004. As a result, it is possible to suppress the contents of the battery 2006 from adhering to the output terminal 2014. Thus, corrosion of the output terminal 2014 and short circuits between the batteries 2006 can be suppressed, and the reliability of the battery module 2001 can be improved.

[0102] Furthermore, the battery 2006 according to this embodiment includes a housing 2020, an electrode body 2024 housed in the housing 2020 and comprising a plurality of positive electrode plates 2040a and a plurality of negative electrode plates 2040b stacked together, a pair of output terminals 2014 arranged on the first surface 2020a of the housing 2020 and electrically connected to the electrode body 2024, a valve portion 2022 arranged on a surface different from the first surface 2020a of the housing 2020 for releasing gas G inside the housing 2020, and a restraining portion 2026 for restraining the edge of the electrode body 2024. The housing 2020 has a surface on which the valve portion is located and a surface on which the valve portion is not located, including the first surface 2020a. The restraining portion 2026 restrains the edge of the electrode body 2024 that faces the surface on which the valve portion is not located.

[0103] By arranging the output terminal 2014 and the valve portion 2022 on different surfaces of the housing 2020, it is possible to suppress the contents of the battery 2006 from adhering to the output terminal 2014. Furthermore, by restraining the edge of the electrode body 2024 facing the surface without the valve portion, the gas G discharged from the electrode body 2024 can be guided towards the valve portion 2022. Therefore, it is possible to promote the release of gas from the valve portion 2022 to the outside of the housing 2020. Thus, according to the battery 2006 of this embodiment, it is possible to suppress corrosion of the output terminal 2014 and short circuits between the batteries 2006 while ensuring the release of gas from the valve portion 2022 to the outside of the housing 2020. Therefore, the reliability of the battery module 2001 can be improved.

[0104] Furthermore, in this embodiment, the non-valve surface has an opposing surface that faces the valve surface, and the restraining portion 2026 restrains the edge of the electrode body 2024 that is closer to the opposing surface than to the valve surface. This further promotes gas release from the electrode body 2024 toward the valve 2022. Moreover, the restraining portion 2026 in this embodiment restrains the edge of the electrode body 2024 that faces the opposing surface. This further promotes gas release from the electrode body 2024 toward the valve 2022.

[0105] Furthermore, in this embodiment, the electrode body 2024 has a first edge portion 2024a facing the valve portion arrangement surface, and a second edge portion 2024b on the opposite side of the first edge portion 2024a. The restraining portion 2026 fixes the second edge portion 2024b on the opposite side of the valve portion 2022 more firmly than the first edge portion 2024a on the valve portion 2022 side. More specifically, the restraining portion 2026 has a first gripping portion 2044 that grips the first edge portion 2024a, and a second gripping portion 2046 that grips the second edge portion 2024b. The first gripping portion 2044 deforms more than the second gripping portion 2046 when subjected to force in the stacking direction of the multiple positive electrode plates 2040a and the multiple negative electrode plates 2040b.

[0106] If the output terminal 2014 and the valve section 2022 are placed on different sides of the housing 2020, the electrode body 2024 may obstruct the discharge of gas from the valve section 2022. In other words, the current collector 2032 is interposed between the output terminal 2014 and the electrode body 2024. For this reason, in conventional batteries where the output terminal 2014 and the valve section 2022 are placed on the same side of the housing 2020, the current collector 2032 was able to ensure the flow path of gas G to the valve section 2022. However, if the output terminal 2014 and the valve section 2022 are placed on different sides of the housing 2020, the current collector 2032 is not interposed between the valve section 2022 and the electrode body 2024. As a result, the electrode body 2024 may block the valve section 2022, potentially obstructing the release of gas from the valve section 2022.

[0107] In contrast, by using the restraining portion 2026 to more firmly fix the second edge portion 2024b on the opposite side of the valve portion 2022 than the first edge portion 2024a on the valve portion 2022 side, it is possible to facilitate the ejection of gas towards the valve portion 2022. In this case, it is possible to suppress the obstruction of gas release from the valve portion 2022 by the electrode body 2024.

[0108] The battery of this embodiment comprises a housing, an electrode body housed in the housing and comprising a plurality of positive electrode plates and a plurality of negative electrode plates stacked together, a pair of output terminals arranged on the first surface of the housing and electrically connected to the electrode body, a valve portion arranged on a surface different from the first surface of the housing for releasing gas inside the housing, and a restraining portion for restraining the edges of the electrode body. The housing has a surface on which the valve portion is located and a surface without the valve portion, including the first surface, and the restraining portion restrains the edges facing the surface without the valve portion.

[0109] Furthermore, the battery module 1 of this embodiment comprises an assembly 2 of multiple batteries 6, a busbar 16 that electrically connects the output terminals 14 of the multiple batteries 6, and a cooling plate 4 that is thermally connected to the busbar 16 and faces the first surface 20a. By connecting the cooling plate 4 to the busbar 16 in this way, the busbar 16 can be efficiently cooled. This makes it possible to increase the capacity of the batteries 6 and the battery module 1 without increasing the size or complexity of the busbar or increasing the thermal capacity of the busbar.

[0110] Furthermore, the heat generated in the busbar 16 can be transferred to the battery 6, preventing the battery 6 from overheating. In addition, the cooling plate 4 can also cool the output terminals 14 and electrode bodies 24 via the busbar 16. As a result, the battery 6 can be cooled efficiently, and a decrease in the power generation performance of the battery module 1 can be suppressed. Moreover, since the heat dissipation structure of the battery module 1 other than the cooling plate 4 can be omitted or reduced, the battery module 1 can be made smaller and less expensive.

[0111] Furthermore, as described above, in this embodiment, the output terminal 14 and the valve 22 of the battery 6 are located on different sides of the outer casing 20. Therefore, even when the cooling plate 4 is connected to the busbar 16, the valve 22 is not covered by the cooling plate 4. Thus, it is possible to prevent the gas G released from the valve 22 from accumulating in the space between the outer casing 20 and the cooling plate 4. As a result, it is possible to suppress the contents of the battery 6 from adhering to the output terminal 14. Thus, corrosion of the output terminal 14 and short circuits between the batteries 6 can be suppressed, and the reliability of the battery module 1 can be improved.

[0112] In this embodiment, the first edge portion 2024a is restrained by the first gripping portion 2044 and the second edge portion 2024b is restrained by the second gripping portion 2046, and the deformation amount of the first gripping portion 2044 is made greater than the deformation amount of the second gripping portion 2046, thereby causing gas G to flow out from the electrode body 2024 to the valve portion 2022 side. However, the structure is not limited to this, and the following modifications can be given to structures that cause gas G to flow out from the electrode body 2024 to the valve portion 2022 side.

[0113] (Variation 1) Figure 21(A) is a schematic cross-sectional view showing the internal structure of the battery according to Modification 1. Note that the current collector 2032 is not shown in Figure 21(A). In the restraining portion 2026 of Modification 1, the total area of ​​the portion gripped by the first gripping portion 2044 at the first edge portion 2024a is smaller than the total area of ​​the portion gripped by the second gripping portion 2046 at the second edge portion 2024b. Note that the area of ​​the portion gripped by each gripping portion is the area of ​​the region in which each gripping portion and the electrode body 2024 overlap when viewed from the stacking direction of the multiple positive electrode plates 2040a and multiple negative electrode plates 2040b.

[0114] In this modified example, each first gripping portion 2044 is smaller than each second gripping portion 2046, and the total number of first gripping portions 2044 is less than the total number of second gripping portions 2046. As a result, the total area of ​​the regions gripped by the first gripping portions 2044 is smaller than the total area of ​​the regions gripped by the second gripping portions 2046. By making the area of ​​the constrained region of the first edge portion 2024a smaller than the area of ​​the constrained region of the second edge portion 2024b, the area of ​​the exposed region at the first edge portion 2024a, i.e., the region not gripped by the first gripping portion 2044, becomes larger than the area of ​​the region at the second edge portion 2024b not gripped by the second gripping portion 2046. In such a structure, if enough gas is generated to cause the electrode body 2024 to swell, the first edge portion 2024a can be expanded more easily than the second edge portion 2024b. Therefore, it is possible to facilitate the outflow of gas G from the electrode body 2024 to the valve portion 2022. Naturally, by making the size of the first gripping portion 2044 smaller than the size of the second gripping portion 2046, or by making the total number of first gripping portions 2044 less than the total number of second gripping portions 2046, the area of ​​the region exposed at the first edge portion 2024a can be made larger than the area of ​​the region exposed at the second edge portion 2024b, and the first edge portion 2024a can be made to be wider than the second edge portion 2024b.

[0115] (Modification 2) Figure 21(B) is a schematic cross-sectional view showing the internal structure of the battery according to Modification 2. In Modification 2, the restraining portion 2026 grips only the second edge portion 2024b of the electrode body 2024. That is, the restraining portion 2026 comprises only the second gripping portion 2046. The first edge portion 2024a of the electrode body 2024 is not restrained by the restraining portion 2026. This embodiment also makes it easier to spread the first edge portion 2024a more than the second edge portion 2024b. Therefore, it is possible to easily allow gas G to flow out from the electrode body 2024 to the valve portion 2022 side.

[0116] (Variation 3) Figure 21(C) is a schematic cross-sectional view showing the internal structure of the battery according to Modified Example 3. In the restraining portion 2026 of Modified Example 3, the distance W1 between the pair of arm portions 2044b in the first gripping portion 2044 is wider than the distance W2 between the pair of arm portions 2046b in the second gripping portion 2046. In other words, with respect to the size of the electrode plates 2040 in the stacking direction, the flat plate portion 2044a is larger than the flat plate portion 2046a. Alternatively, the first gripping portion 2044 is larger than the second gripping portion 2046. Therefore, each electrode plate 2040 has a greater degree of freedom of displacement in the stacking direction at the first edge portion 2024a than at the second edge portion 2024b. This embodiment also makes it easier to widen the first edge portion 2024a than the second edge portion 2024b. Therefore, it is possible to facilitate the outflow of gas G from the electrode body 2024 to the valve portion 2022.

[0117] In Figure 21(C), the flat plate portion 2046a is shown as being sized such that the arm portion 2046b contacts the electrode body 2024, and the flat plate portion 2044a is shown as being sized such that the arm portion 2044b is spaced apart from the electrode body 2024. However, the configuration is not limited to this, and the size of the flat plate portion 2044a may be such that the arm portion 2044b and the electrode body 2024 contact each other, while the flat plate portion 2046a may be smaller than this flat plate portion 2044a. In a configuration where both the arm portions 2044b and 2046b contact the electrode body 2024, if the rigidity of the first gripping portion 2044 and the second gripping portion 2046 are the same, the smaller the dimensions of the flat plate portion, the greater the restraining force applied to the electrode body 2024. In other words, the compression ratio of the electrode body 2024 by the gripping portion increases. Therefore, the gas preferentially flows towards the first edge portion 2024a, which is gripped by the first gripping portion 2044, which has a weaker restraining force compared to the second gripping portion 2046.

[0118] (Modification 4) Figures 22(A) and 22(B) are schematic cross-sectional views showing the internal structure of the battery according to Modified Example 4. In Modified Example 4, the restraining portion 2026 has a third gripping portion 48 that restrains the tab portion 2036, instead of the second gripping portion 2046 that restrains the second edge portion 2024b. The third gripping portion 48 deforms less than the first gripping portion 2044 when subjected to force in the stacking direction of the electrode plate 2040. The third gripping portion 48 is, for example, a cable tie or adhesive tape. This embodiment also makes it easier to spread the first edge portion 2024a more than the second edge portion 2024b. Therefore, it is possible to easily allow gas G to flow out from the electrode body 2024 to the valve portion 2022 side.

[0119] (Embodiment 3) Embodiment 3 has the same configuration as Embodiment 2, except that the structure of the battery 2006 is different. Hereinafter, this embodiment will be described focusing on the configurations that differ from the other embodiments, and the common configurations will be briefly described or omitted. Figure 23 is a schematic cross-sectional view showing the internal structure of the battery according to Embodiment 2.

[0120] The battery 2006 has a housing 2020. The housing 2020 houses the electrode body 2024, electrolyte, etc. A pair of output terminals 2014 are arranged on the first surface 2020a of the housing 2020. A valve section 2022 is arranged on a surface of the housing 2020 different from the first surface 2020a. In this embodiment, the valve section 2022 is arranged on the second surface 2020b, which is opposite the first surface 2020a.

[0121] Each of the pair of output terminals 2014 is electrically connected to the electrode body 2024 via a current collector 2032 located within the housing 2020. The current collector 2032 has a current collector plate 2034 and a tab portion 2036. The electrode body 2024 has a structure in which multiple electrode plates 2040 are stacked. Specifically, the electrode body 2024 has a structure in which positive electrode plates 2040a and negative electrode plates 2040b are stacked alternately. An electrode plate separator 2042 is interposed between adjacent positive electrode plates 2040a and negative electrode plates 2040b.

[0122] Multiple electrode plates 2040 and electrode plate separators 2042 are restrained by a restraining portion 2026. The restraining portion 2026 in this embodiment has a first gripping portion 2044 that grips the first edge portion 2024a of the electrode body 2024 on the valve portion 2022 side, and a second gripping portion 2046 that grips the second edge portion 2024b on the opposite side of the first edge portion 2024a. Unlike Embodiment 2, the deformation amounts of the first gripping portion 2044 and the second gripping portion 2046 when subjected to a force in the stacking direction of the electrode plate 2040 may be the same or different.

[0123] When the battery 2006 is assembled into the battery module 2001, its orientation is set so that the valve portion 2022 faces vertically upward. Therefore, the output terminal 2014 faces vertically downward. In addition, at least a portion of the current collector portion 2032 has enough flexibility to deform under the weight of the electrode body 2024. More specifically, the tab portion 2036 of the current collector portion 2032, which extends from the electrode body 2024 toward the first surface 2020a, has enough flexibility to deform under the weight of the electrode body 2024. Therefore, when the orientation of the battery 2006 is set so that the valve portion 2022 faces vertically upward, the electrode body 2024 is displaced vertically downward, that is, away from the valve portion 2022, due to its own weight. As the electrode body 2024 is displaced, the tab portion 2036 elastically deforms so that the end on the electrode body 2024 side and the end on the current collector plate 2034 side move closer together. As a result, the electrode body 2024 can be moved away from the valve portion 2022. Therefore, a flow path can be secured for the gas inside the housing 2020 to reach the valve portion 2022.

[0124] The valve portion 2022 may also be provided on a surface of the housing 2020 other than the first surface 2020a and the second surface 2020b, for example, the short side 2020c (see Figure 20(B)). In this case, if the valve portion 2022 is oriented vertically upward, the output terminal 2014 will be oriented horizontally. When the electrode body 2024 is displaced vertically downward due to its own weight, the end of the tab portion 2036 on the electrode body 2024 side is displaced vertically downward.

[0125] As described above, the battery 2006 of this embodiment includes a housing 2020, an electrode body 2024 housed in the housing 2020 and comprising a plurality of positive electrode plates 2040a and a plurality of negative electrode plates 2040b stacked together, a pair of output terminals 2014 positioned on the first surface 2020a of the housing 2020 and electrically connected to the electrode body 2024, a valve portion 2022 positioned on a surface different from the first surface 2020a of the housing 2020 for releasing gas inside the housing 2020, and a current collector portion 2032 connecting the output terminals 2014 and the electrode body 2024. The valve portion 2022 faces vertically upward, and at least a portion of the current collector portion 2032 has enough flexibility to deform under the weight of the electrode body 2024. This reduces the possibility of the contents of the battery 2006 adhering to the output terminals 2014 while suppressing obstruction of gas discharge from the valve portion 2022 by the electrode body 2024. Therefore, the reliability of the battery module 2001 can be improved.

[0126] (Embodiment 4) Embodiment 4 has the same configuration as Embodiment 2, except that the structure of the battery 2006 is different.Hereafter, this embodiment will be described focusing on the configurations that differ from Embodiment 2, and the common configurations will be briefly described or omitted.Figure 24(A) is a schematic cross-sectional view showing the internal structure of the battery according to Embodiment 4.Figure 24(B) is a schematic diagram of the electrode body and spacer as seen from the valve side.Figure 24(C) is an enlarged view of the region including the valve.Note that Figure 24(A) corresponds to a cross-sectional view along line AA in Figure 24(B).In addition, the restraining part 2026 and the current collecting part 2032 are not shown in Figure 24(A).In addition, the base part 2051 and the restraining part 2026 are not shown in Figure 24(B).

[0127] The battery 2006 has a housing 2020. The housing 2020 houses the electrode body 2024, electrolyte, etc. A pair of output terminals 2014 are arranged on the first surface 2020a of the housing 2020. A valve section 2022 is arranged on a surface of the housing 2020 different from the first surface 2020a. In this embodiment, the valve section 2022 is arranged on the second surface 2020b, which is opposite the first surface 2020a.

[0128] Each of the pair of output terminals 2014 is electrically connected to the electrode body 2024 via a current collector 2032 located within the housing 2020. The electrode body 2024 has a structure in which multiple electrode plates 2040 are stacked. Specifically, the electrode body 2024 has a structure in which positive electrode plates 2040a and negative electrode plates 2040b are stacked alternately. An electrode plate separator 2042 is interposed between adjacent positive electrode plates 2040a and negative electrode plates 2040b. The multiple electrode plates 2040 and the electrode plate separator 2042 are constrained by a restraining portion 2026.

[0129] Furthermore, the battery 2006 has a spacer 2050 positioned between the electrode body 2024 and the surface of the housing 2020 where the valve portion 2022 is provided, thereby separating the electrode body 2024 and the valve portion 2022. The spacer 2050 suppresses the displacement of the electrode body 2024 toward the valve portion 2022. Therefore, it is possible to prevent the valve portion 2022 from being blocked by the electrode body 2024. This ensures that a flow path is secured for the gas inside the housing 2020 to reach the valve portion 2022.

[0130] The spacer 2050 of this embodiment has a base portion 2051 facing the surface of the housing 2020 on which the valve portion 2022 is located, and a plurality of wall portions 2052. Each wall portion 2052 protrudes toward the electrode body 2024 from the surface of the base portion 2051 facing the electrode body 2024. The tip of each wall portion 2052 abuts against the electrode body 2024. Each wall portion 2052 is made of a resin having, for example, insulating properties and corrosion resistance to electrolyte.

[0131] Each wall portion 2052 extends in a direction intersecting the direction in which the electrode plate 2040 extends. In this embodiment, each electrode plate 2040 extends in direction Y. Therefore, each wall portion 2052 extends in a direction intersecting the direction Y in which each electrode plate 2040 extends. In addition, adjacent wall portions extend parallel to each other, and a groove portion 2054 is formed between adjacent wall portions.

[0132] More specifically, each wall portion 2052 is roughly V-shaped. The extent of each wall portion 2052 in the stacking direction of the electrode plates 2040 overlaps with a portion of the electrode body 2024. The multiple wall portions 2052 are arranged on both sides of the valve portion 2022 in direction Y, at predetermined intervals in the stacking direction of the electrode plates 2040. As a result, multiple roughly V-shaped groove portions 2054 are arranged on both sides of the valve portion 2022 in direction Y, in the stacking direction of the electrode plates 2040. Each groove portion 2054 constitutes a flow path that guides the gas G flowing out from the electrode body 2024 to the valve portion 2022.

[0133] By extending the wall portion 2052 in a direction intersecting the direction in which the electrode plate 2040 extends, it is possible to prevent the electrode plate 2040 from entering the groove portion 2054. Therefore, a flow path for the gas inside the housing 2020 to reach the valve portion 2022 can be secured.

[0134] Each wall portion 2052 has a bellows shape and is arranged at predetermined intervals in the stacking direction of the electrode plates 2040, and may extend over the entire area of ​​the electrode body 2024 in direction Y. In this case, it is preferable that the wall portion 2052 that forms the groove portion 2054 that does not overlap with the valve portion 2022 when viewed from the direction in which the electrode body 2024 and the valve portion 2022 overlap is provided with through holes or notches that penetrate the wall portion 2052 in the thickness direction. This makes it possible to connect the groove portion 2054 that does not overlap with the valve portion 2022 to the valve portion 2022.

[0135] Furthermore, the base portion 2051 has a recess 2051a at a position that overlaps with the valve portion 2022 in the direction in which the base portion 2051 and the second surface 2020b, which is the valve portion arrangement surface, are aligned. The recess 2051a opens toward the electrode body 2024. With this configuration, a thin-walled portion 2051b that overlaps with the valve portion 2022 is formed at the bottom of the recess 2051a. In other words, the base portion 2051 has a thin-walled portion 2051b that constitutes the bottom surface of the recess 2051a.

[0136] For example, the thin-walled portion 2051b is flexible. Therefore, when the valve portion 2022 opens, the thin-walled portion 2051b is pulled by the gas released from the valve portion 2022 and attempts to fly out of the housing 2020 from the valve portion 2022. At this time, if a tensile stress exceeding a predetermined amount is applied to the thin-walled portion 2051b, the thin-walled portion 2051b will tear. As a result, the gas can be released from inside the electrode body 2024 to outside the housing 2020 through the recess 2051a. In other words, the thin-walled portion 2051b has enough flexibility to break when gas is released from the valve portion 2022, due to the pressure of the gas inside the housing 2020 or the pressure of the gas discharged from the valve portion 2022. Alternatively, the thin-walled portion 2051b may have a weak portion 2051c that breaks when gas is released from the valve portion 2022. By providing a weak portion 2051c in the thin-walled portion 2051b, it is possible to promote the fracture of the thin-walled portion 2051b even when the flexibility of the thin-walled portion 2051b is low.

[0137] The recess 2051a can constitute part of the gas flow path from the electrode body 2024 to the valve portion 2022. Therefore, by providing the recess 2051a in the base portion 2051, the reliability of gas release from the valve portion 2022 can be improved. In addition, because the base portion 2051 has a thin-walled portion 2051b, the electrode body 2024 and the housing 2020 can be more reliably insulated when the battery 2006 is in a normal state.

[0138] The base portion 2051 may have a through hole 2051d at a position that overlaps with the valve portion 2022 in the direction in which the valve portion arrangement surface and the base portion 2051 are aligned. By providing the through hole 2051d, the valve portion 2022 and the electrode body 2024 face each other. The through hole 2051d can function as a gas passage when the valve portion 2022 is open. This allows the gas to be released more smoothly from the valve portion 2022.

[0139] Furthermore, the valve portion 2022 may be provided on a surface of the housing 2020 other than the first surface 2020a and the second surface 2020b, for example, the short side surface 2020c (see Figure 24(B)). In this case, the spacer 2050 is provided on the surface of the short side surface 2020c that faces inward from the housing 2020. Also, in Figures 24(A) to 24(C), on the surface of the electrode body 2024 facing the spacer 2050, the area of ​​the area not in contact with the wall portion 2052 is larger than the area of ​​the area in contact with the wall portion 2052, but the configuration is not limited to this. If sufficient gas flow path can be secured, the width of each wall portion 2052 may be widened, etc., to make the area of ​​the area in contact with the wall portion 2052 on the surface of the electrode body 2024 facing the spacer 2050 larger than the area of ​​the area not in contact with the wall portion 2052.

[0140] As described above, the battery 2006 of this embodiment includes an electrode body 2024 housed in a housing 2020, and a spacer 2050 positioned between the electrode body 2024 and the surface of the housing 2020 on which the valve portion 2022 is provided, thereby separating the electrode body 2024 from the valve portion 2022. The electrode body 2024 has a structure in which a plurality of electrode plates 2040 are stacked, and the spacer 2050 has a base portion 2051 facing the surface on which the valve portion is located, and a wall portion 2052 that protrudes from the surface of the base portion 2051 facing the electrode body 2024 and extends in a direction intersecting the direction in which the electrode plates 2040 extend. This makes it possible to reduce the possibility of the contents of the battery 2006 adhering to the output terminal 2014 while suppressing obstruction of gas discharge from the valve portion 2022 by the electrode body 2024. Thus, the reliability of the battery module 2001 can be improved. The following are some possible variations in the shape of the spacer 2050.

[0141] (Variation 5) Figure 25 is a schematic diagram showing the electrode body and spacer in the battery according to Modification 5 as viewed from the valve side. The spacer 2050 of Modification 5 has a plurality of wall portions 2052 that extend parallel to the stacking direction of the electrode plates 2040. Each wall portion 2052 is linear, and its extension in the stacking direction of the electrode plates 2040 overlaps with a part of the electrode body 2024. The plurality of wall portions 2052 are arranged at predetermined intervals in a direction intersecting the stacking direction of the electrode plates 2040, and are also arranged to be staggered in the stacking direction. The same effects as in Embodiment 4 can be obtained with this shape and arrangement of wall portions 2052.

[0142] The number of batteries 2006 in the assembly 2002 and the number of electrode plates 2040 in the electrode body 2024 are not particularly limited. The structure of each part of the assembly 2002, including the shape of the separator 2008 and the fastening structure between the end plate 2010 and the bind bar 2012, is also not particularly limited. Furthermore, in Embodiment 4 and Modification 5, the electrode body 2024 may have a structure in which a plurality of electrode plates 2040 are stacked in at least a part of it. For example, the electrode body 2024 may have a structure in which a pair of positive electrode plates 2040a and negative electrode plates 2040b are wound in a spiral shape. In this case, the wall portion 2052 may extend in a direction intersecting the direction in which the electrode plates 2040 extend in the portion in which the plurality of electrode plates 2040 are stacked. Similarly, in Embodiment 3, the electrode body 2024 may have a structure in which a pair of positive electrode plates 2040a and negative electrode plates 2040b are wound in a spiral shape.

[0143] Furthermore, in the embodiment, when explaining the effects of the restraining portion 2026, the effects are explained under the condition that the electrode body 2024 expands due to the gas. However, it is not essential that the electrode body 2024 expands due to the gas. In other words, this disclosure does not presuppose that the electrode body 2024 expands due to the gas, and is effective even for an electrode body 2024 that does not expand due to the gas.

[0144] Next, embodiments 5, 6, 7, 8, and 9 will be described.

[0145] First, I will explain the conventional technologies and their challenges.

[0146] As explained above, conventional battery modules had room for improvement in achieving both power generation performance and reliability.

[0147] Embodiments 5, 6, 7, 8, and 9 were made in view of these circumstances, and their purpose is to provide a technology that can achieve both power generation performance and reliability in battery modules.

[0148] Embodiments 5, 6, 7, 8, and 9 are battery modules. The battery module comprises an assembly of multiple batteries, a busbar, and a cooling plate. Each battery has a housing, a pair of output terminals located on the first surface of the housing, and a valve located on the first surface for releasing gas inside the housing. The busbar electrically connects the output terminals of the multiple batteries. The cooling plate is thermally connected to the busbar and is positioned so that its first main surface faces the first surface. It has a gas flow section consisting of a bottomed or bottomless hole opening in the direction of arrangement of the assembly and the cooling plate, with at least a portion overlapping the valve when viewed from the direction of arrangement.

[0149] According to embodiments 5, 6, 7, 8, and 9, it is possible to achieve both power generation performance and reliability of the battery module.

[0150] (Embodiment 5) Figure 26 is a perspective view of a battery module according to Embodiment 5. Figure 27 is a perspective view of a battery. Figure 26 shows the cooling plate in a disassembled state. The battery module 4001 comprises an assembly 4002, a bus bar 4004, and a cooling plate 4006. The assembly 4002 has a structure in which a plurality of batteries 4012 are assembled. The assembly 4002 of this embodiment takes the form of a battery group in which a plurality of flat batteries 4012 are stacked, that is, a battery stack. The assembly 4002 has a plurality of batteries 4012, a plurality of separators 4014, a pair of end plates 4016, and a pair of bind bars 4018.

[0151] Each battery 4012 is a rechargeable secondary battery, such as a lithium-ion battery, nickel-metal hydride battery, or nickel-cadmium battery. The battery 4012 is a so-called prismatic battery and has a flattened rectangular parallelepiped housing 4019. The housing 4019 has an outer casing 4020 and a lid 4022. The outer casing 4020 is, for example, a bottomed cylindrical shape and has a substantially rectangular opening (not shown). Electrodes, electrolyte, etc., are housed in the outer casing 4020 through this opening. The opening of the outer casing 4020 is provided with a lid 4022 that seals the substantially rectangular opening of the outer casing 4020. The lid 4022 is, for example, a rectangular plate. The lid 4022 constitutes the first surface 4020a of the housing 4019.

[0152] On the lid 4022, that is, the first surface 4020a of the housing 4019, a positive output terminal 4024 is provided near one end in the longitudinal direction, and a negative output terminal 4024 is provided near the other end. The pair of output terminals 4024 are electrically connected to the positive and negative electrode plates that constitute the electrode body, respectively. Hereinafter, the positive output terminal 4024 will be referred to as the positive terminal 4024a, and the negative output terminal 4024 will be referred to as the negative terminal 4024b. Also, when it is not necessary to distinguish the polarity of the output terminals 4024, the positive terminal 4024a and the negative terminal 4024b will be collectively referred to as the output terminal 4024. The outer casing 4020 and the lid 4022 are conductors, for example, made of metal. For example, the outer casing 4020 and the lid 4022 are made of aluminum, iron, stainless steel, etc. The opening of the lid 4022 and the outer casing 4020 are joined, for example, by laser. Therefore, the housing 4019 has a joint portion 21 that joins the opening of the outer casing 4020 and the peripheral edge of the lid 4022. A pair of output terminals 4024 are each inserted through through holes (not shown) formed in the lid 4022. An insulating sealing member (not shown) is interposed between the pair of output terminals 4024 and each through hole.

[0153] In this description of the embodiment, for convenience, the side on which the lid 4022 is provided (first surface 4020a) will be referred to as the top surface of the battery 4012, and the opposite side as the bottom surface of the battery 4012. The battery 4012 also has four sides connecting the top and bottom surfaces. Two of the four sides are a pair of long sides connected to the long sides of the top and bottom surfaces. These long sides are the largest surfaces (main surfaces) of the six surfaces of the battery 4012. The remaining two sides, excluding the two long sides, are a pair of short sides connected to the short sides of the top and bottom surfaces. In the assembly 4002, the surface on the top side of the battery 4012 will be referred to as the top surface of the assembly 4002, the surface on the bottom side of the battery 4012 will be referred to as the bottom surface of the assembly 4002, and the surface on the short side of the battery 4012 will be referred to as the side surface of the assembly 4002. These directions and positions are defined for convenience. Therefore, for example, the portion defined as the top surface in this disclosure does not necessarily mean that it is located above the portion defined as the bottom surface. For example, in the assembly 4002 of this embodiment, the top surface, i.e., the first surface 4020a of the battery 4012, is positioned so that it faces vertically downward.

[0154] A valve section 4026 is provided on the first surface 4020a of the housing 4019 between a pair of output terminals 4024. The valve section 4026, also called a safety valve, is a mechanism that opens when the internal pressure of the housing 4019 rises above a predetermined value, releasing gas inside the housing 4019. The valve section 4026 of each battery 4012 is connected to a gas duct (not shown), and the gas inside the battery is discharged from the valve section 4026 to the gas duct. For example, the valve section 4026 is composed of a thin-walled section that is thinner than other parts and is provided on a part of the lid 4022, and linear grooves formed on the surface of this thin-walled section. In this configuration, when the internal pressure of the housing 4019 rises, the thin-walled section tears starting from the grooves, causing the valve section 4026 to open. As a result, the gas inside the housing 4019 is released from the valve section 4026. Examples of gas inside the housing 4019 include carbon dioxide, which is produced when the electrolyte is decomposed. Furthermore, the gas released outside the casing 4019 may contain fine particles such as fragments of the battery structure.

[0155] Multiple batteries 4012 are arranged side by side at predetermined intervals such that the long sides of adjacent batteries 4012 face each other. In this embodiment, the direction in which the multiple batteries 4012 are arranged is defined as direction X. The output terminals 4024 of each battery 4012 are arranged to face the same direction. In this embodiment, for convenience, the output terminals 4024 of each battery 4012 are arranged to face vertically downward. However, the output terminals 4024 of each battery 4012 may be arranged to face different directions. The output terminals 4024 of the multiple batteries 4012 are electrically connected to each other by a busbar 4004.

[0156] The busbar 4004 is a roughly strip-shaped member made of a metal such as copper or aluminum. In this embodiment, the multiple batteries 4012 are divided into multiple battery blocks, each consisting of multiple batteries 4012. In each battery block, output terminals 4024 of the same polarity are connected in parallel by the busbar 4004. In addition, output terminals 4024 of opposite polarity in two adjacent battery blocks are connected in series by the busbar 4004. Note that all batteries 4012 may also be connected in series.

[0157] Separator 4014, also called an insulating spacer, is made of, for example, an insulating resin. Each separator 4014 is placed between two adjacent batteries 4012 to electrically insulate them from each other. Some separators 4014 are also placed between a battery 4012 and an end plate 4016 to insulate them from each other. Examples of resins that make up each separator 4014 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl® resin (modified PPE).

[0158] Furthermore, each separator 4014 has a wall portion 4014a that extends in direction X and covers the first surface 4020a of the battery 4012. By covering the first surface 4020a of the battery 4012 with the wall portion 4014a, creepage distance can be secured between adjacent batteries 4012 or between the battery 4012 and the end plate 4016. The wall portion 4014a has openings (not shown) at positions corresponding to the output terminal 4024 and at positions corresponding to the valve portion 4026, respectively, so that the output terminal 4024 or the valve portion 4026 is exposed to the outside.

[0159] Furthermore, the battery module 4001 has a cylindrical gas induction section 4030. The gas induction section 4030 is positioned to surround the opening of the separator 4014 that exposes the valve section 4026. In this embodiment, the gas induction section 4030 is integrally molded with the separator 4014. The structure of the gas induction section 4030 will be described in detail later. Note that the gas induction section 4030 can be omitted in the battery module 4001.

[0160] Multiple batteries 4012 and multiple separators 4014, arranged side by side, are sandwiched between a pair of end plates 4016. The pair of end plates 4016 are positioned adjacent to the batteries 4012 located at both ends in direction X, via the separators 4014. The end plates 4016 are made of, for example, metal plates. On the surface of the end plate 4016 facing the long side of the battery 4012, screw holes (not shown) into which screws 4028 are screwed are provided.

[0161] The pair of bind bars 4018 are elongated members with direction X as their longitudinal direction. The pair of bind bars 4018 are arranged facing each other in direction Y, which is perpendicular to direction X and parallel to the longitudinal direction of the first surface 4020a. Between the pair of bind bars 4018 are a plurality of batteries 4012, a plurality of separators 4014, and a pair of end plates 4016. Each bind bar 4018 has a rectangular planar portion 4018a extending parallel to the side surface of the assembly 4002, and four overhang portions 4018b protruding from each end of the planar portion 4018a toward the batteries 4012. Two overhang portions 4018b facing each other in direction X are provided with through holes (not shown) through which screws 4028 are inserted. The planar portion 4018a is provided with an opening 4018c that exposes the short side surface of the battery 4012.

[0162] Multiple batteries 4012 and multiple separators 4014 are arranged alternately and sandwiched in direction X by a pair of end plates 4016, and then sandwiched in direction Y by a pair of bind bars 4018. Each bind bar 4018 is positioned so that the through hole in the overhang portion 4018b aligns with the screw hole in the end plate 4016. Then, a screw 4028 is inserted through the through hole and screwed into the screw hole. In this way, the multiple batteries 4012 are restrained by the engagement of the pair of bind bars 4018 with the pair of end plates 4016.

[0163] Multiple batteries 4012 are positioned in direction X by being clamped in direction X by a bind bar 4018. The top and bottom surfaces of the multiple batteries 4012 are in contact with two opposing overhangs 4018b in direction Z, where the top and bottom surfaces are aligned, via a separator 4014. This positions the multiple batteries 4012 in direction Z. For example, after this positioning is complete, a bus bar 4004 is attached to the output terminal 4024 of each battery 4012, electrically connecting the output terminals 4024 of the multiple batteries 4012. For example, the bus bar 4004 is fixed to the output terminal 4024 by welding.

[0164] The assembly 4002 has a cooling plate 4006 covering the side on which the output terminal 4024 protrudes. The cooling plate 4006 is a plate-shaped member and has a first main surface 4006a and a second main surface 4006b. The second main surface 4006b faces the first main surface 4006a. The cooling plate 4006 is positioned so that the first main surface 4006a faces the first surface 4020a of each battery 4012. A busbar 4004 is interposed between the cooling plate 4006 and the assembly 4002. The cooling plate 4006 is made of a material with high thermal conductivity, such as aluminum. The cooling plate 4006 also has a flow path 4006c (see Figure 28(B)) through which a coolant such as water or ethylene glycol flows. The cooling plate 4006 also has a gas flow section 4032. The structure of cooling plate 4006 will be described in detail later.

[0165] The cooling plate 4006 is thermally connected to each busbar 4004 via a heat conduction member 4008. The heat conduction member 4008 is interposed between each busbar 4004 and the cooling plate 4006, and contacts each busbar 4004 and the cooling plate 4006. For example, the heat conduction member 4008 is fixed to the busbar 4004 with an adhesive. When the assembly 4002, to which the busbar 4004 and the heat conduction member 4008 are fixed, is placed on the cooling plate 4006, the heat conduction member 4008 comes into contact with the cooling plate 4006. The heat conduction member 4008 has high thermal conductivity as well as insulating properties. This prevents the busbar 4004 and the cooling plate 4006 from being electrically connected via the heat conduction member 4008.

[0166] As the heat conductive member 4008, a known resin sheet having good thermal conductivity, such as acrylic rubber or silicone rubber, can be used. In this embodiment, a substantially rectangular parallelepiped heat conductive member 4008 is arranged at a position that overlaps with each output terminal 4024 in the arrangement direction (direction Z) of the assembly 4002 and the cooling plate 4006. The surface of each heat conductive member 4008 facing the bus bar 4004 abuts against the main surface of the bus bar 4004, and the surface of each heat conductive member 4008 facing the cooling plate 4006 abuts against the first main surface 4006a of the cooling plate 4006.

[0167] Through the heat conductive member 4008, each busbar 4004 and the cooling plate 4006 are thermally, or in a heat-exchangeable manner, connected, so that each busbar 4004 is cooled by the cooling plate 4006, and consequently each battery 4012 is cooled. By cooling each busbar 4004 using the cooling plate 4006, the cooling efficiency of the busbars 4004 and the batteries 4012 can be further increased. Furthermore, by providing the heat conductive member 4008 in a position that overlaps with the output terminal 4024 in the arrangement direction of the assembly 4002 and the cooling plate 4006, the heat conduction path from the output terminal 4024 to the cooling plate 4006 can be shortened. This improves the cooling efficiency of the output terminal 4024 and consequently the batteries 4012.

[0168] The assembly 4002 and the cooling plate 4006 each have insertion portions (not shown) at predetermined positions through which fastening members such as screws are inserted. The assembly 4002 and the cooling plate 4006 are fixed to each other by the fastening members being inserted into the insertion portions. The fastening members that fix the assembly 4002 and the cooling plate 4006 may also be used to fix the cooling plate 4006 to the module case. Preferably, the fastening portions of the assembly 4002 are provided in a position that does not overlap with the battery 4012 when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006. For example, the fastening portions of the assembly 4002 are provided on the end plate 4016 or the bind bar 4018.

[0169] Figure 28(A) is a schematic bottom view of the battery module. Figure 28(B) is a cross-sectional view along line AA in Figure 28(A). In Figure 28(B), the internal structure of the battery 4012 and the separator 4014 are not shown.

[0170] The cooling plate 4006 is a flat tube and has a first plate portion 4034 facing the assembly 4002 and a second plate portion 4036 on the opposite side from the first plate portion 4034. The first plate portion 4034 and the second plate portion 4036 face each other with a predetermined gap between them, and a plurality of flow channels 4006c are arranged in this gap. The first plate portion 4034 constitutes the first main surface 4006a, and the second plate portion 4036 constitutes the second main surface 4006b. Each flow channel 4006c is arranged to extend in direction X with a predetermined distance between them in direction Y. A refrigerant supply channel (not shown) is connected to one end of each flow channel 4006c in direction X, and a refrigerant discharge channel (not shown) is connected to the other end. Such a cooling plate 4006 can be formed by combining known methods, such as forming a gas flow section 4032 on a plate with a plurality of flow channels 4006c obtained by extrusion molding or the like using a press.

[0171] The cooling plate 4006 may also be formed by joining a first plate portion 4034 and a second plate portion 4036, which are separate entities. For example, the cooling plate 4006 can be obtained by joining a plate material having grooves in the shape of flow channels 4006c and a plate material without grooves by brazing or the like.

[0172] As described above, the cooling plate 4006 has a gas flow section 4032. The gas flow section 4032 is a mechanism for guiding the gas released from the valve section 4026 of each battery 4012 from the space on the first main surface 4006a side of the cooling plate 4006 to the space on the opposite side, the second main surface 4006b side. In this embodiment, the gas flow section 4032 is composed of a bottomless hole that opens in the direction of arrangement (direction Z) of the assembly 4002 and the cooling plate 4006. In other words, the gas flow section 4032 is composed of a through hole that extends from the first main surface 4006a to the second main surface 4006b. The diameter of the through hole is constant from the first main surface 4006a side to the second main surface 4006b side. The bottomless hole constituting the gas flow section 4032 can be formed by performing known processing such as punching on the plate material constituting the cooling plate 4006. The gas released from the valve portion 4026 of each battery 4012 is sent through the gas flow section 4032 to the space on the second main surface 4006b side of the cooling plate 4006. In addition, the cooling plate 4006 may have multiple flow paths 4006c divided by the gas flow section 4032 in a cross section in the Z-axis direction. In this configuration, the distance between two adjacent flow paths 4006c separated by the gas flow section 4032 may be greater than the distance between two adjacent flow paths 4006c not separated by the gas flow section 4032.

[0173] If the cooling plate 4006 is positioned to cover the first surface 4020a of each battery 4012, the diffusion of gas released from the valve 4026 may be obstructed by the cooling plate 4006. In contrast, by providing a gas flow section 4032 on the cooling plate 4006, the gas released from the valve 4026 can be quickly removed from the space between the cooling plate 4006 and the battery 4012. This prevents the contents of the battery 4012 from adhering to the output terminal 4024.

[0174] Furthermore, the cooling plate 4006 of this embodiment has a plurality of gas flow sections 4032. Each gas flow section 4032 corresponds to a valve section 4026 of each battery 4012. Specifically, each gas flow section 4032 is arranged such that at least a portion of it overlaps with each valve section 4026 when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006. Preferably, the gas flow section 4032 is arranged to overlap with the center of the valve section 4026. The center of the valve section 4026 is, for example, the geometric center or geometric centroid of the contour shape of the valve section 4026 when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006.

[0175] Furthermore, in this embodiment, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, the entire periphery of each valve section 4026 is located within the region enclosed by the periphery of the end of each gas flow section 4032 on the first main surface 4006a side. In other words, the entire valve section 4026 is included in the extended region of the end of each gas flow section 4032 on the first main surface 4006a side. The gas flow section 4032 in this embodiment is a bottomless hole opening to the first main surface 4006a and the second main surface 4006b. Therefore, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a. Consequently, the entire valve section 4026 is located within the opening on the first main surface 4006a side of each gas flow section 4032. This arrangement allows the gas released from the valve section 4026 to flow more reliably into the gas flow section 4032.

[0176] Furthermore, an output terminal 4024, a busbar 4004, and a heat conduction member 4008 are interposed between the first surface 4020a of the battery 4012 and the first main surface 4006a of the cooling plate 4006. Therefore, the valve section 4026 and the gas flow section 4032 are spaced apart in the direction of arrangement of the assembly 4002 and the cooling plate 4006. A cylindrical gas guide section 4030 is placed in the gap 4038 between the valve section 4026 and the gas flow section 4032. The gas guide section 4030 is positioned so that the opening of the cylinder faces the direction of arrangement of the assembly 4002 and the cooling plate 4006. One end of the gas guide section 4030 surrounds the valve section 4026, and the other end surrounds the gas flow section 4032. The gas released from the valve section 4026 passes through the inside of the gas guide section 4030 and reaches the gas flow section 4032. This suppresses the diffusion of gas into gap 4038.

[0177] In this embodiment, the gas induction section 4030 is integrally molded with the separator 4014. Therefore, examples of materials that constitute the gas induction section 4030 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl® resin (modified PPE). The gas induction section 4030 may be a separate component from the separator 4014, and may be integrally molded with, for example, the cooling plate 4006. Furthermore, the gas induction section 4030 may be a separate component independent of the separator 4014 and the cooling plate 4006.

[0178] As described above, the battery module 4001 of this embodiment comprises an assembly 4002 of a plurality of batteries 4012, a busbar 4004, and a cooling plate 4006. Each battery 4012 has a housing 4019 and a pair of output terminals 4024 and a valve portion 4026 arranged on the first surface 4020a of the housing 4019. The busbar 4004 electrically connects the output terminals 4024 of the plurality of batteries 4012 to each other. The cooling plate 4006 is thermally connected to the busbar 4004 and is arranged so that its first main surface 4006a faces the first surface 4020a of the battery 4012. The cooling plate 4006 also has a gas flow section 4032 which is composed of a bottomless hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. When viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, at least a portion of the gas flow section 4032 overlaps with the valve section 4026.

[0179] By thermally connecting the cooling plate 4006 to the busbar 4004, the busbar 4004 can be efficiently cooled. This allows for increased capacity of the battery 4012 and battery module 4001 without increasing the size or complexity of the busbar, thereby increasing the heat capacity of the busbar. Furthermore, it prevents heat generated in the busbar 4004 from being transferred to the battery 4012 and causing its temperature to rise. In addition, the cooling plate 4006 can also cool the output terminal 4024 and electrode body via the busbar 4004. Therefore, the battery 4012 can be efficiently cooled, and a decrease in the power generation performance of the battery module 4001 can be suppressed. Moreover, since the heat dissipation structure of the battery module 4001 other than the cooling plate 4006 can be omitted or reduced, the battery module 4001 can be made smaller and less expensive.

[0180] Furthermore, the cooling plate 4006 in this embodiment has a gas flow section 4032 which is composed of through holes that open in the direction of arrangement between the assembly 4002 and the cooling plate 4006. The gas released from the valve section 4026 is discharged through the gas flow section 4032 into the space on the second main surface 4006b side of the cooling plate 4006. Therefore, it is possible to suppress the accumulation of gas released from the valve section 4026 in the space between the battery 4012 and the cooling plate 4006. As a result, it is possible to suppress the contents of the battery 4012 from adhering to the output terminal 4024. Thus, corrosion of the output terminal 4024 and short circuits between the batteries 4012 can be suppressed, and the reliability of the battery module 4001 can be improved. Based on the above, this embodiment makes it possible to achieve both power generation performance and reliability of the battery module 4001.

[0181] Furthermore, in this embodiment, the entire periphery of the valve portion 4026 is located within the region enclosed by the periphery of the end portion 4032a on the first main surface 4006a side of the gas flow portion 4032, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006. This allows the gas released from the valve portion 4026 to flow more reliably into the gas flow portion 4032. In addition, the battery module 4001 has a cylindrical gas guide portion 4030 that is positioned in the gap 4038 between the valve portion 4026 and the gas flow portion 4032. This allows the gas released from the valve portion 4026 to flow more reliably into the gas flow portion 4032.

[0182] In this embodiment, the gas flow section 4032 is configured without a bottom hole. However, the gas flow section 4032 is not particularly limited to this structure. The gas flow section 4032 may have the structures of the following modified examples 1 and 2. In the following modified examples 1 and 2, the focus will be on the configurations that differ from Embodiment 5, and common configurations will be briefly described or omitted.

[0183] (Variation 1) Figure 29(A) is a schematic cross-sectional view showing a battery module according to Modification 1. In Figure 29(A), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 1 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the first main surface 4006a side. In other words, the gas flow section 4032 is composed of a recess that opens on the second main surface 4006b side. The bottomed hole constituting the gas flow section 4032 can be formed by applying known processing such as press working to the plate material constituting the cooling plate 4006.

[0184] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the first main surface 4006a. The thin-walled portion 4040 is thinner than the thickness of the cooling plate 4006 from the first main surface 4006a to the second main surface 4006b. Preferably, the thin-walled portion 4040 is thinner than the thickness of the first plate portion 4034, in other words, the thickness from the inner surface facing the first main surface 4006a in the flow path 4006c to the first main surface 4006a.

[0185] When gas is released from the valve portion 4026 of each battery 4012, the pressure of this gas causes the thin-walled portion 4040 to tear. As a result, in the battery module 4001, the space on the first main surface 4006a side of the cooling plate 4006 and the space on the second main surface 4006b side are connected via the gas flow portion 4032. Consequently, the gas released from the valve portion 4026 is sent through the gas flow portion 4032 to the space on the second main surface 4006b side of the cooling plate 4006. Therefore, it is possible to suppress the contents of the battery 4012 from adhering to the output terminal 4024, thereby improving the reliability of the battery module 4001.

[0186] When a gas flow section 4032 is provided in the cooling plate 4006, heat transfer in the planar direction of the cooling plate 4006 tends to be hindered by the gas flow section 4032. In contrast, the thin-walled section 4040 can function as a heat conduction path extending in the planar direction of the cooling plate 4006 when the valve section 4026 of the battery 4012 is not in operation. Therefore, by configuring the gas flow section 4032 as a bottomed hole, that is, by providing the thin-walled section 4040 in the cooling plate 4006, the decrease in the heat diffusion efficiency of the cooling plate 4006 can be suppressed. As a result, the decrease in the cooling efficiency of the busbar 4004 and the battery 4012 can be suppressed.

[0187] Furthermore, the thin-walled portion 4040 in this embodiment is integrally molded with the surrounding area of ​​the bottomed hole. In other words, the thin-walled portion 4040 is a part of the first plate portion 4034. This makes it possible to increase the thermal conductivity between the surrounding area of ​​the thin-walled portion 4040 and the thin-walled portion 4040 compared to when the thin-walled portion 4040 is a separate part from the surrounding area. In addition, it is possible to suppress an increase in the number of parts and structural complexity of the battery module 4001.

[0188] The thin-walled portion 4040 may be separate from the surrounding area. In this case, the cooling plate 4006 can be punched to form through holes, and the openings provided on the first main surface 4006a can be closed with a heat-conducting sheet or the like that constituting the thin-walled portion 4040 to form the gas flow portion 4032. In this case, the gas flow portion 4032 can be formed more easily than the gas flow portion 4032 in which the thin-walled portion 4040 is integrated with the surrounding area. Also, in this modified example, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, the entire periphery of each valve portion 4026 is located within the region surrounded by the end of each gas flow portion 4032 on the first main surface 4006a side, that is, the periphery of the bottom surface 4032c.

[0189] (Modification 2) Figure 29(B) is a schematic cross-sectional view showing a battery module according to Modification 2. In Figure 29(B), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 2 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the second main surface 4006b side. In other words, the gas flow section 4032 is composed of a recess that opens on the first main surface 4006a side.

[0190] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the second main surface 4006b. The thin-walled portion 4040 is thinner than the thickness of the cooling plate 4006 from the first main surface 4006a to the second main surface 4006b. Preferably, the thin-walled portion 4040 is thinner than the thickness of the second plate portion 4036, in other words, the thickness from the inner surface facing the second main surface 4006b in the flow path 4006c to the second main surface 4006b.

[0191] When gas is released from the valve portion 4026 of each battery 4012, the pressure of this gas causes the thin-walled portion 4040 to split, and the space on the first main surface 4006a side and the space on the second main surface 4006b side of the cooling plate 4006 are connected via the gas flow portion 4032. In addition, by providing the thin-walled portion 4040, a decrease in the thermal diffusion efficiency of the cooling plate 4006 can be suppressed. Furthermore, in this modified example, the gas flow portion 4032 opens on the first main surface 4006a side. Therefore, compared to a gas flow portion 4032 that opens on the second main surface 4006b side, it is possible to introduce the gas released from the valve portion 4026 into the gas flow portion 4032 more easily.

[0192] Furthermore, the thin-walled portion 4040 is integrally molded with the surrounding area of ​​the bottomed hole. In other words, the thin-walled portion 4040 is a part of the second plate portion 4036. This makes it possible to increase the thermal conductivity between the surrounding area of ​​the thin-walled portion 4040 and the thin-walled portion 4040 compared to when the thin-walled portion 4040 is a separate part from the surrounding area. It also makes it possible to suppress an increase in the number of parts and structural complexity of the battery module 4001. In this modified example as well, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, the entire periphery of each valve portion 4026 is located within the region surrounded by the end of each gas flow portion 4032 on the first main surface 4006a side, that is, the periphery of the opening on the first main surface 4006a side.

[0193] In Modification 1, the thin-walled portion 4040 is positioned flush with the first main surface 4006a, while in Modification 2, the thin-walled portion 4040 is positioned flush with the second main surface 4006b. However, the positioning of the thin-walled portion 4040 is not limited to these, and it can be provided at any position between the first main surface 4006a and the second main surface 4006b.

[0194] (Embodiment 6) Embodiment 6 has the same configuration as Embodiment 5, except that the gas flow section has a tapered shape. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 5, while common configurations will be briefly described or omitted. Figure 30 is a schematic cross-sectional view showing a battery module according to Embodiment 6. In Figure 30, the internal structure of the battery 4012 and the separator 4014 are not shown.

[0195] The battery module 4001 comprises an assembly 4002, a busbar 4004, and a cooling plate 4006. The assembly 4002 has a plurality of batteries 4012. A pair of output terminals 4024 and a valve portion 4026 are arranged on the first surface 4020a of each battery 4012. The busbar 4004 electrically connects the output terminals 4024 of the plurality of batteries 4012 to each other. The cooling plate 4006 is thermally connected to the busbar 4004 via a heat conductive member 4008, and is positioned so that its first main surface 4006a faces the first surface 4020a.

[0196] The cooling plate 4006 is composed of a bottomless hole that opens in the direction of arrangement (direction Z) of the assembly 4002 and the cooling plate 4006, and has a gas flow section 4032 that overlaps with the valve section 4026 in at least a portion when viewed from the direction of arrangement. The gas flow section 4032 has a shape in which the gas flow area N perpendicular to the direction of arrangement of the assembly 4002 and the cooling plate 4006 gradually changes from one end to the other in the direction of arrangement. Such a gas flow section 4032 can be formed by performing known processing such as punching on the plate material constituting the cooling plate 4006.

[0197] In this embodiment, the gas flow section 4032 has a flow path area N at the end on the first main surface 4006a side that is smaller than the flow path area N at the end on the second main surface 4006b side. The gas flow section 4032 in this embodiment is a bottomless hole that opens to the first main surface 4006a and the second main surface 4006b. Therefore, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a, and the end on the second main surface 4006b side is the end 4032b which is included in the same plane as the second main surface 4006b. Consequently, the bottomless hole constituting the gas flow section 4032 has an opening on the first main surface 4006a side that is smaller than the opening on the second main surface 4006b side.

[0198] In other words, the gas flow section 4032 in this embodiment is tapered so that the flow path widens gradually or continuously from the first main surface 4006a to the second main surface 4006b. In this embodiment as well, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve section 4026 is entirely located within the opening on the first main surface 4006a side of each gas flow section 4032.

[0199] The battery module 4001 according to this embodiment also achieves a balance between power generation performance and reliability, similar to embodiment 5. Furthermore, the gas flow section 4032 in this embodiment has a tapered shape such that the flow area N on the side farther from the valve section 4026 is larger than the flow area N on the side closer to the valve section 4026. In other words, the gas flow section 4032 has a shape in which the gas outlet is larger than the gas inlet. This makes it easier to move the gas flowing into the gas flow section 4032 towards the outlet. Therefore, the gas released from the valve section 4026 can be easily released through the space on the second main surface 4006b side of the cooling plate 4006.

[0200] In this embodiment, the gas flow section 4032 is configured without a bottom hole. However, the gas flow section 4032 is not particularly limited to this structure. The gas flow section 4032 may have the structures of the following modified examples 3 and 4. In the following modified examples 3 and 4, the differences from Embodiment 6 will be described, and common configurations will be briefly described or omitted. Note that the modified examples 3 and 4 for this embodiment have the same correspondence as the modified examples 1 and 2 for Embodiment 5.

[0201] (Variation 3) Figure 31(A) is a schematic cross-sectional view showing a battery module according to Modification 3. In Figure 31(A), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 3 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the first main surface 4006a side. In other words, the gas flow section 4032 is composed of a recess that opens on the second main surface 4006b side. The bottomed hole constituting the gas flow section 4032 can be formed by applying known processing such as press working to the plate material constituting the cooling plate 4006.

[0202] The gas flow section 4032 has a shape in which the flow area N at the end on the first main surface 4006a side is smaller than the flow area N at the end on the second main surface 4006b side, and the flow area N gradually changes from one end to the other. Since the gas flow section 4032 is a bottomed hole opening to the second main surface 4006b, the end on the first main surface 4006a side is the bottom surface 4032c of the bottomed hole, and the end on the second main surface 4006b side is the end 4032b that is included in the same plane as the second main surface 4006b. Therefore, in this modified example, the gas flow section 4032 is tapered so that the flow path widens gradually or continuously from the bottom surface 4032c towards the opening on the second main surface 4006b side.

[0203] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the first main surface 4006a. Furthermore, the thin-walled portion 4040 is integrally molded with the periphery of the bottomed hole. In other words, the thin-walled portion 4040 is a part of the first plate portion 4034. Also, in this modified example, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve portion 4026 is located within a region where its entire periphery is surrounded by the periphery of the bottom surface 4032c of each gas flow portion 4032.

[0204] (Modification 4) Figure 31(B) is a schematic cross-sectional view showing a battery module according to Modification 4. In Figure 31(B), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 4 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the second main surface 4006b side. In other words, the gas flow section 4032 is composed of a recess that opens on the first main surface 4006a side.

[0205] The gas flow section 4032 has a shape in which the flow area N at the end on the first main surface 4006a side is smaller than the flow area N at the end on the second main surface 4006b side, and the flow area N gradually changes from one end to the other. Since the gas flow section 4032 is a bottomed hole opening into the first main surface 4006a, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a, and the end on the second main surface 4006b side is the bottom surface 4032c of the bottomed hole. Therefore, in this modified example, the gas flow section 4032 is tapered so that the flow path widens gradually or continuously from the opening on the first main surface 4006a side to the bottom surface 4032c on the second main surface 4006b side.

[0206] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the second main surface 4006b. Furthermore, the thin-walled portion 4040 is integrally molded with the periphery of the bottomed hole. In other words, the thin-walled portion 4040 is a part of the second plate portion 4036. Also, in this modified example, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve portion 4026 is located within a region where its entire periphery is surrounded by the periphery of the opening on the first main surface 4006a side of each gas flow portion 4032.

[0207] In Modification 3, the thin-walled portion 4040 is positioned flush with the first main surface 4006a, and in Modification 4, the thin-walled portion 4040 is positioned flush with the second main surface 4006b. However, the positioning of the thin-walled portion 4040 is not limited to these, and it can be provided at any position between the first main surface 4006a and the second main surface 4006b.

[0208] (Embodiment 7) Embodiment 7 has a configuration common to Embodiment 5 or 6, except that the gas flow section has a tapered shape opposite to that of Embodiment 6. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 5 or 6, and the common configurations will be briefly described or omitted. Figure 32 is a schematic cross-sectional view showing a battery module according to Embodiment 7. In Figure 32, the internal structure of the battery 4012 and the separator 4014 are not shown.

[0209] The battery module 4001 comprises an assembly 4002, a busbar 4004, and a cooling plate 4006. The assembly 4002 has a plurality of batteries 4012. A pair of output terminals 4024 and a valve portion 4026 are arranged on the first surface 4020a of each battery 4012. The busbar 4004 electrically connects the output terminals 4024 of the plurality of batteries 4012 to each other. The cooling plate 4006 is thermally connected to the busbar 4004 via a heat conductive member 4008, and is positioned so that its first main surface 4006a faces the first surface 4020a.

[0210] The cooling plate 4006 is composed of a bottomless hole that opens in the direction of arrangement (direction Z) of the assembly 4002 and the cooling plate 4006, and has a gas flow section 4032 that overlaps with the valve section 4026 in at least a portion when viewed from the direction of arrangement. Furthermore, the gas flow section 4032 has a shape in which the gas flow area N perpendicular to the direction of arrangement of the assembly 4002 and the cooling plate 4006 gradually changes from one end to the other in the direction of arrangement.

[0211] In this embodiment, the gas flow section 4032 has a larger flow area N at the end on the first main surface 4006a side than at the end on the second main surface 4006b side. The gas flow section 4032 in this embodiment is a bottomless hole opening to the first main surface 4006a and the second main surface 4006b. Therefore, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a, and the end on the second main surface 4006b side is the end 4032b which is included in the same plane as the second main surface 4006b. Consequently, the bottomless hole constituting the gas flow section 4032 has a larger opening on the first main surface 4006a side than on the second main surface 4006b side.

[0212] In other words, the gas flow section 4032 in this embodiment is tapered so that the flow path narrows gradually or continuously from the first main surface 4006a to the second main surface 4006b. In this embodiment as well, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve section 4026 is entirely located within the opening on the first main surface 4006a side of each gas flow section 4032.

[0213] The battery module 4001 according to this embodiment also achieves a balance between power generation performance and reliability, similar to embodiment 5. Furthermore, the gas flow section 4032 in this embodiment has a tapered shape such that the flow path area N on the side closer to the valve section 4026 is larger than the flow path area N on the side further from the valve section 4026. In other words, the gas flow section 4032 has a shape in which the gas inlet is larger than the gas outlet. This makes it easier to introduce the gas released from the valve section 4026 into the gas flow section 4032. In other words, the gas flow section 4032 has a shape in which the gas outlet is smaller than the gas inlet. This makes it possible to suppress the entry of gas released into the space on the second main surface 4006b side of the cooling plate 4006 into the gas flow section 4032.

[0214] In this embodiment, the gas flow section 4032 is configured without a bottom hole. However, the gas flow section 4032 is not particularly limited to this structure. The gas flow section 4032 may have the structures of the following modified examples 5 and 6. In the following modified examples 5 and 6, the differences from Embodiment 7 will be described, and common configurations will be briefly described or omitted. Note that the modified examples 5 and 6 for this embodiment have the same correspondence as the modified examples 3 and 4 for Embodiment 6.

[0215] (Variation 5) Figure 33(A) is a schematic cross-sectional view showing a battery module according to Modification 5. In Figure 33(A), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 5 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the first main surface 4006a side. In other words, the gas flow section 4032 is composed of a recess that opens on the second main surface 4006b side.

[0216] The gas flow section 4032 has a shape in which the flow area N at the end on the first main surface 4006a side is larger than the flow area N at the end on the second main surface 4006b side, and the flow area N gradually changes from one end to the other. Since the gas flow section 4032 is a bottomed hole opening to the second main surface 4006b, the end on the first main surface 4006a side is the bottom surface 4032c of the bottomed hole, and the end on the second main surface 4006b side is the end 4032b that is included in the same plane as the second main surface 4006b. Therefore, in this modified example, the gas flow section 4032 is tapered so that the flow path narrows in stages or continuously from the bottom surface 4032c towards the opening on the second main surface 4006b side.

[0217] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the first main surface 4006a. Furthermore, the thin-walled portion 4040 is integrally molded with the periphery of the bottomed hole. In other words, the thin-walled portion 4040 is a part of the first plate portion 4034. Also, in this modified example, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve portion 4026 is located within a region where its entire periphery is surrounded by the periphery of the bottom surface 4032c of each gas flow portion 4032.

[0218] (Experimental variation 6) Figure 33(B) is a schematic cross-sectional view showing a battery module according to Modification 6. In Figure 33(B), the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 6 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the second main surface 4006b side. In other words, the gas flow section 4032 is composed of a recess that opens on the first main surface 4006a side.

[0219] The gas flow section 4032 has a shape in which the flow area N at the end on the first main surface 4006a side is larger than the flow area N at the end on the second main surface 4006b side, and the flow area N gradually changes from one end to the other. Since the gas flow section 4032 is a bottomed hole opening into the first main surface 4006a, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a, and the end on the second main surface 4006b side is the bottom surface 4032c of the bottomed hole. Therefore, in this modified example, the gas flow section 4032 is tapered so that the flow path narrows in stages or continuously from the opening on the first main surface 4006a side to the bottom surface 4032c on the second main surface 4006b side.

[0220] The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is positioned to be substantially flush with the second main surface 4006b. Furthermore, the thin-walled portion 4040 is integrally molded with the periphery of the bottomed hole. In other words, the thin-walled portion 4040 is a part of the second plate portion 4036. In this modified example, the gas flow portion 4032 opens toward the first main surface 4006a, and the flow area N gradually decreases toward the thin-walled portion 4040. This allows the gas released from the valve portion 4026 to be concentrated toward the thin-walled portion 4040. Therefore, the thin-walled portion 4040 can be more reliably broken. Consequently, the thickness of the thin-walled portion 4040 can be increased to improve the thermal diffusion efficiency of the cooling plate 4006. Furthermore, in this modified example as well, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve portion 4026 is located within a region where its entire periphery is surrounded by the periphery of the opening on the first main surface 4006a side of each gas flow portion 4032.

[0221] In Modification 5, the thin-walled portion 4040 is positioned flush with the first main surface 4006a, and in Modification 6, the thin-walled portion 4040 is positioned flush with the second main surface 4006b. However, the positioning of the thin-walled portion 4040 is not limited to these, and it can be provided at any position between the first main surface 4006a and the second main surface 4006b.

[0222] (Embodiment 8) Embodiment 8 has the same configuration as Embodiment 5, except that the gas flow section has a constricted shape. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 5, and the common configurations will be briefly described or omitted. Figure 34 is a schematic cross-sectional view showing a battery module according to Embodiment 8. In Figure 34, the internal structure of the battery 4012 and the separator 4014 are not shown.

[0223] The battery module 4001 comprises an assembly 4002, a busbar 4004, and a cooling plate 4006. The assembly 4002 has a plurality of batteries 4012. A pair of output terminals 4024 and a valve portion 4026 are arranged on the first surface 4020a of each battery 4012. The busbar 4004 electrically connects the output terminals 4024 of the plurality of batteries 4012 to each other. The cooling plate 4006 is thermally connected to the busbar 4004 via a heat conductive member 4008, and is positioned so that its first main surface 4006a faces the first surface 4020a.

[0224] The cooling plate 4006 is composed of a bottomless hole that opens in the direction of arrangement (direction Z) of the assembly 4002 and the cooling plate 4006, and has a gas flow section 4032 that overlaps with the valve section 4026 in at least a portion when viewed from the direction of arrangement. The gas flow section 4032 has a shape in which the gas flow area N perpendicular to the direction of arrangement of the assembly 4002 and the cooling plate 4006 gradually changes from one end to the other in the direction of arrangement. Such a gas flow section 4032 can be formed by performing known processing such as punching on the plate material constituting the cooling plate 4006.

[0225] The gas flow section 4032 has a constricted portion 4032d between the end on the first main surface 4006a side and the end on the second main surface 4006b side. In this embodiment, the constricted portion 4032d is located in the central part of the gas flow section 4032 in the direction of arrangement of the assembly 4002 and the cooling plate 4006. The gas flow area N in the gas flow section 4032 is minimized at the constricted portion 4032d. That is, the flow area N gradually decreases from the end on the first main surface 4006a side toward the constricted portion 4032d, and gradually increases from the constricted portion 4032d toward the end on the second main surface 4006b side. The gas flow section 4032 in this embodiment is a bottomless hole that opens to the first main surface 4006a and the second main surface 4006b. Therefore, the end on the first main surface 4006a side is the end 4032a which is included in the same plane as the first main surface 4006a, and the end on the second main surface 4006b side is the end 4032b which is included in the same plane as the second main surface 4006b.

[0226] Therefore, in this embodiment, the gas flow section 4032 is tapered such that the flow path narrows gradually or continuously from the first main surface 4006a toward the constricted portion 4032d, and widens gradually or continuously from the constricted portion 4032d toward the second main surface 4006b. In this embodiment as well, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve section 4026 is entirely located within the opening on the first main surface 4006a side of each gas flow section 4032.

[0227] The battery module 4001 according to this embodiment also achieves a balance between power generation performance and reliability, similar to embodiment 5. Furthermore, the gas flow section 4032 in this embodiment has a tapered shape in the portion from the end on the first main surface 4006a side to the constricted portion 4032d such that the flow area N on the side closer to the valve section 4026 is larger than the flow area N on the side further from the valve section 4026. This makes it easier to introduce the gas released from the valve section 4026 into the gas flow section 4032. In addition, it is possible to suppress the backflow of gas released into the space on the second main surface 4006b side of the cooling plate 4006 to the battery 4012 side.

[0228] Furthermore, the gas flow section 4032 has a tapered shape in the portion from the constricted section 4032d to the second main surface 4006b such that the flow area N on the side further from the valve section 4026 is larger than the flow area N on the side closer to the valve section 4026. This makes it easier to release the gas released from the valve section 4026 into the space on the second main surface 4006b side of the cooling plate 4006.

[0229] In this embodiment, the gas flow section 4032 is configured without a bottom hole. However, the gas flow section 4032 is not particularly limited to this structure. The gas flow section 4032 may have the structure of the following modified example 7. In the following modified example 7, the differences from Embodiment 8 will be described in detail, and common configurations will be briefly described or omitted. Note that the modified example 7 for this embodiment has the same correspondence as the modified examples 1 and 2 for Embodiment 5.

[0230] (Example 7) Figure 35 is a schematic cross-sectional view showing a battery module according to Modification 7. In Figure 10, the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 7 consists of two closed holes that open in the direction of arrangement of the assembly 4002 and the cooling plate 4006. Specifically, the gas flow section 4032 consists of a first closed hole 4042 that opens into the first main surface 4006a and a second closed hole 4044 that opens into the second main surface 4006b. The first closed hole 4042 and the second closed hole 4044 are arranged so that their bottom surfaces 4042c and 44c face each other. The bottom surfaces 4042c and 44c are arranged with a predetermined gap between them.

[0231] In the first bottomed hole 4042, the flow channel area N at the end 4032a on the first main surface 4006a side is larger than the flow channel area N at the end on the second main surface 4006b side, i.e., the bottom surface 4042c. In other words, the first bottomed hole 4042 is tapered so that the flow channel narrows gradually or continuously from the opening on the first main surface 4006a side toward the bottom surface 4042c. On the other hand, in the second bottomed hole 4044, the flow channel area N at the end 4032b on the second main surface 4006b side is larger than the flow channel area N at the end on the first main surface 4006a side, i.e., the bottom surface 44c. In other words, the second bottomed hole 4044 is tapered so that the flow channel widens gradually or continuously from the bottom surface 44c toward the opening on the second main surface 4006b side. Therefore, in this modified example, a constricted portion 4032d is formed by the end of the first bottomed hole 4042 on the second main surface 4006b side and the end of the second bottomed hole 4044 on the first main surface 4006a side.

[0232] The gas flow section 4032 has a shape in which the gas flow area N, perpendicular to the arrangement direction of the assembly 4002 and the cooling plate 4006, gradually changes from one end to the other in the arrangement direction. In this modified example of the gas flow section 4032, the flow area N gradually decreases from the end 4032a on the first main surface 4006a side toward the constricted portion 4032d, and the flow area N gradually increases from the constricted portion 4032d toward the end 4032b on the second main surface 4006b side.

[0233] The cooling plate 4006 has a thin-walled portion 4040 that forms the bottom surface 4042c of the first bottomed hole 4042 and the bottom surface 44c of the second bottomed hole 4044. In this modified example, the portion sandwiched between the bottom surfaces 4042c and 44c constitutes the thin-walled portion 4040. Furthermore, the thin-walled portion 4040 is integrally molded with the periphery of the bottomed hole. Also in this modified example, when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, each valve portion 4026 is located within a region where its entire periphery is surrounded by the periphery of the opening on the first main surface 4006a side of each gas flow portion 4032.

[0234] In this modified example, the thin-walled portion 4040 is located in the constricted portion 4032d, but the location of the thin-walled portion 4040 is not limited to this, and it can be provided at any position between the first main surface 4006a and the second main surface 4006b.

[0235] (Embodiment 9) Embodiment 9 has the same configuration as Embodiment 5, except that the shapes of the gas induction section 4030 and the cooling plate 4006 are different.Hereafter, this embodiment will be described focusing on the configurations that differ from Embodiment 5, and the common configurations will be briefly described or omitted.Figure 36 is a schematic cross-sectional view showing a battery module according to Embodiment 9.Figure 36 omits the illustration of the internal structure of the battery 4012 and the separator 4014.

[0236] The battery module 4001 comprises an assembly 4002, a busbar 4004, and a cooling plate 4006. The assembly 4002 has a plurality of batteries 4012. A pair of output terminals 4024 and a valve portion 4026 are arranged on the first surface 4020a of each battery 4012. The busbar 4004 electrically connects the output terminals 4024 of the plurality of batteries 4012 to each other. The cooling plate 4006 is thermally connected to the busbar 4004 via a heat conductive member 4008, and is positioned so that its first main surface 4006a faces the first surface 4020a.

[0237] The cooling plate 4006 is composed of a bottomless hole that opens in the direction of arrangement (direction Z) of the assembly 4002 and the cooling plate 4006, and has a gas flow section 4032 that overlaps with the valve section 4026 in at least a portion when viewed from the direction of arrangement. The battery module 4001 also has a gas guide section 4030 in the gap 4038 between the valve section 4026 and the gas flow section 4032. The gas guide section 4030 in this embodiment has a cylindrical section 4046 and a flange section 4048.

[0238] The cylindrical portion 4046 is positioned so that its opening faces the direction of arrangement of the assembly 4002 and the cooling plate 4006. One opening of the cylindrical portion 4046 is connected to the valve portion 4026. The other opening of the cylindrical portion 4046 is connected to the gas flow portion 4032. The gas released from the valve portion 4026 passes through the inside of the cylindrical portion 4046 to the gas flow portion 4032. The flange portion 4048 extends from the outer surface of the cylindrical portion 4046 to the outside of the cylinder. By providing the flange portion 4048, the strength of the cylindrical portion 4046 can be increased. This makes it possible to suppress deformation of the cylindrical portion 4046 due to the pressure of the gas released from the valve portion 4026.

[0239] The cooling plate 4006 in this embodiment has a stepped portion 4050 on its first main surface 4006a that surrounds the gas flow portion 4032. The stepped portion 4050 has a bottom surface 4050a that extends parallel to the first main surface 4006a at a position closer to the second main surface 4006b than the first main surface 4006a, and an inner surface 4050b that connects the first main surface 4006a and the bottom surface 4050a. Therefore, the first main surface 4006a is lower at the stepped portion 4050. The inner surface 4050b has a shape similar to the cylindrical portion 4046 when viewed from the direction of arrangement of the assembly 4002 and the cooling plate 4006, and is slightly larger than the outer diameter of the cylindrical portion 4046.

[0240] The gas guide portion 4030 engages with the stepped portion 4050 at the end of the cylindrical portion 4046 on the cooling plate 4006 side. In other words, the end of the cylindrical portion 4046 on the cooling plate 4006 side is positioned within the stepped portion 4050. In this state, the bottom surface 4050a and the lower end surface of the cylindrical portion 4046 are in contact, and the inner surface 4050b and the outer surface of the cylindrical portion 4046 face each other. As a result, the gas flow portion 4032 is positioned in the direction in which the first main surface 4006a extends, that is, in the in-plane direction of the first main surface 4006a. As a result, it is possible to suppress displacement of the gas guide portion 4030 due to the pressure of the gas released from the valve portion 4026. Preferably, with the end of the cylindrical portion 4046 engaged with the stepped portion 4050, the surface of the flange portion 4048 facing the first main surface 4006a comes into contact with the first main surface 4006a. This further suppresses deformation of the cylindrical portion 4046.

[0241] In this embodiment, the gas flow section 4032 is configured without a bottom hole. However, the gas flow section 4032 is not particularly limited to this structure. The gas flow section 4032 may have the structure of the following modified example 8. In the following modified example 8, the differences from Embodiment 9 will be described in detail, and common configurations will be briefly described or omitted. Note that the modified example 8 for this embodiment has the same correspondence as the modified example 1 for Embodiment 5.

[0242] (Variation 8) Figure 37 is a schematic cross-sectional view showing a battery module according to Modification 8. In Figure 37, the internal structure of the battery 4012 and the separator 4014 are not shown. The gas flow section 4032 of Modification 8 is composed of a bottomed hole that opens in the direction of arrangement of the assembly 4002 and the cooling plate 4006. In this modification, the bottom surface 4032c of the bottomed hole is located on the first main surface 4006a side. That is, the gas flow section 4032 is composed of a recess that opens on the second main surface 4006b side. The cooling plate 4006 has a thin-walled portion 4040 that constitutes the bottom surface 4032c of the bottomed hole. The thin-walled portion 4040 is arranged to be substantially flush with the first main surface 4006a. The thin-walled portion 4040 is also integrally molded with the periphery of the bottomed hole. That is, the thin-walled portion 4040 is a part of the first plate portion 4034.

[0243] Furthermore, the battery module 4001 has a gas induction section 4030. The gas induction section 4030 has a cylindrical section 4046 and a flange section 4048. One opening of the cylindrical section 4046 is connected to a valve section 4026, and the other opening is connected to a gas flow section 4032. The flange section 4048 extends from the outer surface of the cylindrical section 4046 outwards. The cooling plate 4006 in this embodiment has a stepped section 4050 on the first main surface 4006a that surrounds the gas flow section 4032. More specifically, the stepped section 4050 surrounds the bottom surface 4032c of the gas flow section 4032, in other words, the thin-walled section 4040. In this modified example, the stepped section 4050 is composed of a groove that extends along the periphery of the bottom surface 4032c. The gas flow section 4032 engages with the stepped section 4050 at the end of the cylindrical section 4046 on the cooling plate 4006 side. In other words, the end of the cylindrical section 4046 on the cooling plate 4006 side is fitted into the groove that constitutes the stepped section 4050.

[0244] Although not shown in the diagram, the thin-walled portion 4040 may be provided on the second main surface 4006b side, similar to the modified example 2. Furthermore, the thin-walled portion 4040 may be provided at any position between the first main surface 4006a and the second main surface 4006b.

[0245] In each of the embodiments and modifications described above, when a gas guide section 4030 is provided, the relationship between the area Sv of the region surrounded by the periphery of the valve section 4026, the flow path area Sg of the gas guide section 4030, and the flow path area Sf of the gas circulation section 4032 may be Sv ≤ Sf ≤ Sg. By providing the gas guide section 4030, the gas released from the valve section 4026 flows more easily into the gas circulation section 4032. Therefore, the decrease in the amount of gas flowing into the gas circulation section 4032 that occurs when the flow path area Sf of the gas circulation section 4032 is reduced can be suppressed by installing the gas guide section 4030. In other words, the required flow path area Sf of the gas circulation section 4032 can be reduced. This suppresses the need to enlarge the gas circulation section 4032 and further improves the cooling efficiency of the cooling plate 4006.

[0246] The number of batteries 4012 and the number of heat conduction members 4008 in the assembly 4002 are not particularly limited. The structure of each part of the assembly 4002, including the shape of the separator 4014 and the fastening structure between the end plate 4016 and the bind bar 4018, is also not particularly limited. The battery module 4001 may include a busbar plate. The busbar plate is a plate-shaped member that is positioned facing the first surface 4020a of the plurality of batteries 4012 and covers the first surface 4020a. In this embodiment, the busbar plate corresponds to an assembly of wall portions 4014a provided by each separator 4014.

[0247] Next, embodiments 10, 11, 12, and 13 will be described.

[0248] In recent years, there has been a growing demand for higher capacity battery modules, and to meet this demand, the capacity of batteries themselves is increasing. When batteries have higher capacity, a large current flows through the busbars that connect them to each other. This increases the amount of heat generated in the busbars. When the amount of heat generated in the busbars increases, heat is transferred from the busbars to the batteries, causing the batteries to heat up and potentially reducing their power generation performance.

[0249] One way to suppress heat generation in busbars is to place cooling plates against them. However, batteries, busbars, and cooling plates each have dimensional tolerances. Therefore, it is not easy to thermally connect all busbars to the cooling plates, and there is a risk that the heat dissipation effect from the cooling plates will be uneven across each busbar. In this case, the power generation performance of batteries connected to busbars that are not adequately cooled may decrease. A decrease in the power generation performance of individual batteries leads to a decrease in the overall power generation performance of the battery module.

[0250] Embodiments 10, 11, 12, and 13 were made in view of these circumstances, and their purpose is to provide a technology for suppressing the deterioration of the power generation performance of battery modules.

[0251] Embodiments 10, 11, 12, and 13 are battery modules. The battery module comprises an assembly of a plurality of batteries, each having a housing and a pair of output terminals arranged on the first surface of the housing; a plurality of busbars that electrically connect the output terminals of the plurality of batteries; a cooling plate arranged to face the first surface with the plurality of busbars in between; an insulating heat conductive member that contacts the busbars and the cooling plate to thermally connect the busbars and the cooling plate; and an expandable / contractable mechanism that can elastically deform and contract to bias the surface of the heat conductive member against the busbars or the cooling plate.

[0252] According to embodiments 10, 11, 12, and 13, the decrease in the power generation performance of the battery module can be suppressed.

[0253] (Embodiment 10) Figure 38 is a perspective view of a battery module according to Embodiment 10. Figure 39 is a perspective view of a battery. Figure 38 shows the cooling plate in a disassembled state. The battery module 5001 comprises an assembly 5002, a plurality of busbars 5004, a cooling plate 5006, a heat conduction member 5008, a displacement restricting part 5010, and an expansion / contraction mechanism 5030. The assembly 5002 has a structure in which a plurality of batteries 5012 are assembled. The assembly 5002 of this embodiment takes the form of a battery group in which a plurality of flat batteries 5012 are stacked, that is, a battery stack. The assembly 5002 has a plurality of batteries 5012, a plurality of separators 5014, a pair of end plates 5016, and a pair of bind bars 5018.

[0254] Each battery 5012 is a rechargeable secondary battery, such as a lithium-ion battery, nickel-metal hydride battery, or nickel-cadmium battery. The battery 5012 is a so-called prismatic battery and has a flattened rectangular parallelepiped housing 5019. The housing 5019 has an outer casing 5020 and a lid 5022. One side of the outer casing 5020 is provided with a substantially rectangular opening (not shown), through which electrodes, electrolyte, etc., are housed in the outer casing 5020. The opening of the outer casing 5020 is provided with a lid 5022 that seals the opening of the outer casing 5020. The lid 5022 is, for example, a rectangular plate. The lid 5022 constitutes the first surface 5020a of the housing 5019.

[0255] On the lid 5022, that is, the first surface 5020a of the housing 5019, a positive output terminal 5024 is provided near one end in the longitudinal direction, and a negative output terminal 5024 is provided near the other end. The pair of output terminals 5024 are each electrically connected to the positive electrode plate and the negative electrode plate that constitute the electrode assembly. Hereinafter, the positive output terminal 5024 will be appropriately referred to as a positive terminal 5024a, and the negative output terminal 5024 will be referred to as a negative terminal 5024b. In addition, when it is not necessary to distinguish the polarity of the output terminals 5024, the positive terminal 5024a and the negative terminal 5024b are collectively referred to as the output terminal 5024. The outer can 5020 and the lid 5022 are conductors, for example, made of metal. For example, the outer can 5020 and the lid 5022 are made of aluminum, iron, stainless steel, or the like. The lid 5022 and the opening of the outer can 5020 are joined by, for example, laser welding. For this reason, the housing 5019 has a joint portion 5021 that joins the opening of the outer can 5020 and the peripheral edge of the lid 5022. The pair of output terminals 5024 are each inserted into a through hole (not shown) formed in the lid 5022. An insulating seal member (not shown) is interposed between the pair of output terminals 5024 and each through hole.

[0256] In this description of the embodiment, for convenience, the side on which the lid 5022 is provided (first surface 5020a) will be referred to as the top surface of the battery 5012, and the opposite side (bottom surface of the outer casing 5020) will be referred to as the bottom surface of the battery 5012. The battery 5012 also has four sides connecting the top surface and the bottom surface. Two of the four sides are a pair of long sides connected to the long sides of the top surface and the bottom surface. These long sides are the largest surfaces (main surfaces) of the six surfaces that the battery 5012 has. The remaining two sides, excluding the two long sides, are a pair of short sides connected to the short sides of the top surface and the bottom surface. Furthermore, in the assembly 5002, the surface on the top side of the battery 5012 is referred to as the top surface of the assembly 5002, the surface on the bottom side of the battery 5012 is referred to as the bottom surface of the assembly 5002, and the surface on the short side of the battery 5012 is referred to as the side surface of the assembly 5002. These directions and positions are defined for convenience only. Therefore, for example, the portion defined as the top surface in this disclosure does not necessarily mean that it is located above the portion defined as the bottom surface. For example, in the assembly 5002 of this embodiment, the top surface, i.e., the first surface 5020a of the battery 5012, is positioned so that it faces vertically downward.

[0257] A safety valve 5026 is provided between a pair of output terminals 5024 on the lid 5022. The safety valve 5026 is a mechanism that opens when the internal pressure of the housing 5019 rises above a predetermined value, releasing the internal gas. The safety valve 5026 of each battery 5012 is connected to a gas duct (not shown), and the gas inside the battery is discharged from the safety valve 5026 into the gas duct. For example, the safety valve 5026 is composed of a thin-walled portion that is thinner than other parts of the lid 5022 and linear grooves formed on the surface of this thin-walled portion. In this configuration, when the internal pressure of the housing 5019 rises, the thin-walled portion tears starting from the grooves, causing the safety valve 5026 to open.

[0258] The plurality of batteries 5012 are arranged in parallel at predetermined intervals such that the long side surfaces of adjacent batteries 5012 face each other. In the present embodiment, the direction in which the plurality of batteries 5012 are arranged is defined as direction X. Further, the output terminals 5024 of each battery 5012 are arranged so as to face the same direction as each other. In the present embodiment, for convenience, the output terminals 5024 of each battery 5012 are arranged to face downward in the vertical direction. Note that the output terminals 5024 of the respective batteries 5012 may be arranged to face different directions. The output terminals 5024 of the plurality of batteries 5012 are electrically connected to each other by the plurality of bus bars 5004.

[0259] Each bus bar 5004 is a substantially strip-shaped member made of a metal such as copper or aluminum. In the present embodiment, the plurality of batteries 5012 are grouped into a plurality of battery blocks each composed of a plurality of batteries 5012. Then, in each battery block, output terminals 5024 of the same polarity are connected in parallel to each other by the bus bar 5004. Further, output terminals 5024 of different polarities of two adjacent battery blocks are connected in series to each other by the bus bar 5004. Note that all the batteries 5012 may be connected in series.

[0260] The separator 5014, also called an insulating spacer, is made of, for example, an insulating resin. Each separator 5014 is disposed between two adjacent batteries 5012 to electrically insulate between the two batteries 5012. Further, some separators 5014 are disposed between the battery 5012 and the end plate 5016 to insulate between the battery 5012 and the end plate 5016. Examples of the resin constituting each separator 5014 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl (registered trademark) resin (modified PPE).

[0261] Furthermore, each separator 5014 has a wall portion 5014a that extends in direction X and covers the first surface 5020a of the battery 5012. By covering the first surface 5020a of the battery 5012 with the wall portion 5014a, creepage distance can be secured between adjacent batteries 5012 or between the battery 5012 and the end plate 5016. The wall portion 5014a has an opening 5014b at a position corresponding to the safety valve 5026, so that the safety valve 5026 is exposed to the outside.

[0262] Multiple batteries 5012 and multiple separators 5014, arranged side by side, are sandwiched between a pair of end plates 5016. The pair of end plates 5016 are positioned adjacent to the batteries 5012 located at both ends in direction X, via the separators 5014. The end plates 5016 are made of, for example, metal plates. Screw holes (not shown) into which screws 5028 are screwed are provided on the surfaces of the end plates 5016 that face the long sides of the batteries 5012.

[0263] The pair of bind bars 5018 are elongated members with direction X as their longitudinal direction. The pair of bind bars 5018 are arranged facing each other in direction Y, which is perpendicular to direction X and parallel to the longitudinal direction of the first surface 5020a. Between the pair of bind bars 5018 are a plurality of batteries 5012, a plurality of separators 5014, and a pair of end plates 5016. Each bind bar 5018 has a rectangular planar portion 5018a extending parallel to the side surface of the assembly 5002, and four overhang portions 5018b protruding from each end of the planar portion 5018a toward the batteries 5012. Two overhang portions 5018b facing each other in direction X are provided with through holes (not shown) through which screws 5028 are inserted. The planar portion 5018a is provided with an opening 5018c that exposes the short side surface of the battery 5012.

[0264] Multiple batteries 5012 and multiple separators 5014 are arranged alternately and sandwiched in direction X by a pair of end plates 5016, and then sandwiched in direction Y by a pair of bind bars 5018. Each bind bar 5018 is positioned so that the through hole in the overhang portion 5018b aligns with the screw hole in the end plate 5016. Then, a screw 5028 is inserted through the through hole and screwed into the screw hole. In this way, the multiple batteries 5012 are restrained by the engagement of the pair of bind bars 5018 with the pair of end plates 5016.

[0265] Multiple batteries 5012 are positioned in direction X by being clamped in direction X by a bind bar 5018. The top and bottom surfaces of the multiple batteries 5012 are in contact with two opposing overhangs 5018b in direction Z, where the top and bottom surfaces are aligned, via a separator 5014. This positions the multiple batteries 5012 in direction Z. For example, after these positioning steps are completed, a bus bar 5004 is attached to the output terminal 5024 of each battery 5012, electrically connecting the output terminals 5024 of the multiple batteries 5012. For example, the bus bar 5004 is fixed to the output terminal 5024 by welding.

[0266] The assembly 5002 has a cooling plate 5006 covering the side on which the output terminal 5024 protrudes. The cooling plate 5006 is positioned to face the first surface 5020a of each battery 5012. A busbar 5004 is interposed between the cooling plate 5006 and the assembly 5002. The cooling plate 5006 is made of a material with high thermal conductivity, such as aluminum. The cooling plate 5006 may also have internal channels through which a coolant such as water or ethylene glycol flows.

[0267] The heat conduction member 5008 is interposed between each busbar 5004 and the cooling plate 5006, and contacts each busbar 5004 and the cooling plate 5006. For example, the heat conduction member 5008 is fixed to the busbar 5004 with an adhesive. When the assembly 5002, to which the busbar 5004 and the heat conduction member 5008 are fixed, is placed on the cooling plate 5006, the heat conduction member 5008 comes into contact with the cooling plate 5006. The heat conduction member 5008 has high thermal conductivity as well as insulating properties. This prevents the busbar 5004 and the cooling plate 5006 from being electrically connected via the heat conduction member 5008.

[0268] As the heat conductive member 5008, a known resin sheet with good thermal conductivity, such as acrylic rubber or silicone rubber, can be used. In this embodiment, a substantially rectangular parallelepiped heat conductive member 5008 is arranged at a position that overlaps with each output terminal 5024 in the arrangement direction (direction Z) of the assembly 5002 and the cooling plate 5006. The surface of each heat conductive member 5008 facing the bus bar 5004 is in contact with the main surface of the bus bar 5004, and the surface facing the cooling plate 5006 is in contact with the main surface of the cooling plate 5006.

[0269] Each busbar 5004 and the cooling plate 5006 are thermally, or heat-exchangeably, connected via the heat conductive member 5008. This allows the cooling plate 5006 to cool each busbar 5004, and consequently, each battery 5012. Cooling each busbar 5004 using the cooling plate 5006 further enhances the cooling efficiency of both the busbars 5004 and the batteries 5012. Furthermore, by positioning the heat conductive member 5008 in a location overlapping with the output terminal 5024 in the arrangement direction of the assembly 5002 and the cooling plate 5006, the heat conduction path from the output terminal 5024 to the cooling plate 5006 can be shortened. This further improves the cooling efficiency of the output terminal 5024 and, consequently, the batteries 5012. The joint between the output terminal 5024 and the current collector that electrically and thermally connects the output terminal 5024 and the electrode body tends to have high resistance due to its structure and is therefore prone to overheating. For this reason, it is desirable to prioritize the cooling of the output terminal 5024.

[0270] The assembly 5002 and the cooling plate 5006 each have an insertion portion (not shown) at a predetermined position through which a fastening member such as a screw is inserted. The assembly 5002 and the cooling plate 5006 are fixed to each other by the fastening member being inserted into the insertion portion. The fastening member that fixes the assembly 5002 and the cooling plate 5006 may also be used to fix the cooling plate 5006 to the module case. Preferably, the fastening portion of the assembly 5002 is provided in a position that does not overlap with the battery 5012 when viewed from the direction of arrangement of the assembly 5002 and the cooling plate 5006. For example, the fastening portion of the assembly 5002 is provided on the end plate 5016 or the bind bar 5018.

[0271] The displacement restricting section 5010 is interposed between the assembly 5002 and the cooling plate 5006 to maintain the distance between the first surface 5020a of the battery 5012 and the cooling plate 5006. When the battery module 5001 is subjected to an impact due to vibration of the object to which the battery module 5001 is fixed, the assembly 5002 and the cooling plate 5006 may be displaced in a direction that brings them closer together. When the cooling plate 5006 approaches the assembly 5002, a load may be applied to the output terminal 5024 via the bus bar 5004.

[0272] In contrast, the battery module 5001 of this embodiment has a displacement restricting portion 5010 interposed between the assembly 5002 and the cooling plate 5006. The displacement restricting portion 5010 comes into contact with both the assembly 5002 and the cooling plate 5006 when they are displaced in a direction that brings them closer together. This prevents the assembly 5002 and the cooling plate 5006 from coming closer together. In other words, the distance between the assembly 5002 and the cooling plate 5006 is maintained by the dimensions of the displacement restricting portion 5010. As a result, the load that may be applied to the output terminal 5024 when the assembly 5002 and the cooling plate 5006 are displaced in a direction that brings them closer together can be reduced.

[0273] Furthermore, it is more preferable that the displacement restricting portion 5010 is in contact with both the assembly 5002 and the cooling plate 5006 when the assembly 5002 and the cooling plate 5006 are not displaced. This further reduces the load on the output terminal 5024. However, in actual use of the battery module 5001, a mixture of displacement restricting portions 5010 that are in contact with both the assembly 5002 and the cooling plate 5006 and displacement restricting portions 5010 that are in contact with only one of them may exist. The structure of the displacement restricting portion 5010 will be described in detail later.

[0274] Furthermore, dimensional tolerances may be included in the protrusion height of the output terminal 5024 from the first surface 5020a, and in the thickness of the bus bar 5004, cooling plate 5006, and heat conduction member 5008. As a result, when the assembly 5002 is placed on the cooling plate 5006, some of the heat conduction member 5008 may not be in contact with the cooling plate 5006. In contrast, the battery module 5001 according to this embodiment has an expansion / contraction mechanism 5030 that maintains contact between the heat conduction member 5008 and the bus bar 5004, and between the heat conduction member 5008 and the cooling plate 5006, thereby ensuring thermal connection between the bus bar 5004 and the cooling plate 5006.

[0275] In this embodiment, the expansion / contraction mechanism 5030 is formed by the heat conductive member 5008. That is, the heat conductive member 5008 in this embodiment is elastic or flexible. The specific examples of the heat conductive member 5008 listed above have sufficient elasticity to function as the expansion / contraction mechanism 5030. When the battery module 5001 is assembled, the heat conductive member 5008 is elastically deformed by being sandwiched between the bus bar 5004 and the cooling plate 5006, and can take on a contracted state. Furthermore, the amount of contraction of the heat conductive member 5008 changes according to the size of the gap between the bus bar 5004 and the cooling plate 5006. Therefore, tolerances of each component can be absorbed by the heat conductive member 5008.

[0276] The expansion / contraction mechanism 5030 can elastically deform and contract to bias the surface of the heat conduction member 5008 against the bus bar 5004 or the cooling plate 5006. In this embodiment, the heat conduction member 5008 itself constitutes the expansion / contraction mechanism 5030, and by contracting, the heat conduction member 5008 can bias the surface of the heat conduction member 5008 against the bus bar 5004 and the cooling plate 5006. In this way, the heat conduction member 5008 is pressed against both the bus bar 5004 and the cooling plate 5006, thereby maintaining the thermal connection between the cooling plate 5006 and the bus bar 5004. It is preferable that the dimensions of the heat conduction member 5008 in the alignment direction of the assembly 5002 and the cooling plate 5006 be set sufficiently large so as to reliably absorb the tolerances of each member and maintain the thermal connection between the cooling plate 5006 and the bus bar 5004. Therefore, when the battery module 5001 is assembled, preferably all of the heat conductive members 5008 are interposed between the busbar 5004 and the heat conductive members 5008 in a state of being compressed to some extent.

[0277] Next, the structure of the displacement restricting section 5010 will be described in detail. Figure 3 is a cross-sectional view of the battery module. Figure 41 is a cross-sectional view showing an enlarged view of the area including the output terminals of the battery module. In Figures 40 and 41, the internal structures of the battery 5012 and the cooling plate 5006 are not shown.

[0278] The displacement restricting portion 5010 is provided on the surface of the separator 5014 facing the cooling plate 5006. In other words, the displacement restricting portion 5010 is composed of a protrusion that extends from the wall portion 5014a of the separator 5014 toward the cooling plate 5006. Specifically, the wall portion 5014a of the separator 5014 that covers the first surface 5020a of the battery 5012 has a notch 5014c at a position corresponding to the output terminal 5024, so that the output terminal 5024 is exposed to the outside. The displacement restricting portion 5010 is provided at both ends of the notch 5014c in the direction Y where the pair of output terminals 5024 are aligned. In other words, in this embodiment, a pair of displacement restricting portions 5010 are arranged on either side of the output terminal 5024.

[0279] The displacement restricting portion 5010 satisfies the following requirements for the dimension H1 in the arrangement direction of the assembly 5002 and the cooling plate 5006. The dimension H1 of the displacement restricting portion 5010 is defined as the distance from the first surface 5020a to the end of the displacement restricting portion 5010 on the opposite side from the first surface 5020a. In the present embodiment, since the displacement restricting portion 5010 is provided on the assembly 5002, the dimension H1 is the protruding height of the displacement restricting portion 5010 protruding from the first surface 5020a. That is, the dimension H1 of the displacement restricting portion 5010 is equal to or less than the protruding height H2 protruding from the first surface 5020a in the laminated structure of the output terminal 5024, the bus bar 5004, the heat conductive member 5008, and the expansion / contraction mechanism 5030. When the protruding height of the output terminal 5024 protruding from the first surface 5020a is defined as H3, the dimension of the bus bar 5004 in the arrangement direction of the assembly 5002 and the cooling plate 5006 is defined as H4, the dimension of the heat conductive member 5008 in the arrangement direction is defined as H5, and the dimension of the expansion / contraction mechanism 5030 in the arrangement direction is defined as H6, in the present embodiment where the heat conductive member 5008 also serves as the expansion / contraction mechanism 5030, the dimension H1 of the displacement restricting portion 5010 satisfies the condition of H1≦H3+H4+H5 or H1≦H3+H4+H6. In addition, when the expansion / contraction mechanism 5030 has a structure separate from the heat conductive member 5008, the dimension H1 satisfies the condition of H1≦H3+H4+H5+H6.

[0280] Note that, when two members constituting the laminated structure overlap when viewed from a direction perpendicular to the arrangement direction of the assembly 5002 and the cooling plate 5006 by means of fitting, inserting, locking, or the like, the dimension of the overlapping portion of these two members is calculated as the dimension of either one of the members and is not included in the dimension of the other member. In addition, in the laminated structure, the dimension of a portion that does not overlap with the first surface 5020a when viewed from the arrangement direction and protrudes toward the bottom surface side of the outer can 5020 beyond the first surface 5020a is not included in the calculation. Furthermore, in the laminated structure, the dimension of a portion that does not overlap with the main surface of the cooling plate 5006 when viewed from the arrangement direction and protrudes in a direction away from the first surface 5020a beyond the main surface is also not included in the calculation.

[0281] By setting the dimension H1 of the displacement restricting section 5010 to be less than or equal to the sum of the dimensions of the output terminal 5024, bus bar 5004, heat conduction member 5008, and expansion / contraction mechanism 5030, the state in which the output terminal 5024 and bus bar 5004 are electrically connected and the state in which the bus bar 5004 and cooling plate 5006 are thermally connected can be maintained more reliably. The dimension H6 of the expansion / contraction mechanism 5030 is preferably the dimension when the expansion / contraction mechanism 5030 is not contracted.

[0282] Furthermore, it is preferable that the dimension H1 of the displacement restricting section 5010 is greater than the sum of the protrusion height H3 of the output terminal 5024 and the dimension H4 of the bus bar 5004. In other words, the displacement restricting section 5010 protrudes further toward the cooling plate 5006 than the bus bar 5004. This allows the displacement restricting section 5010 to more reliably reduce the load on the output terminal 5024.

[0283] Furthermore, the displacement restricting section 5010 has a larger spring constant than the expansion / contraction mechanism 5030. In other words, the displacement restricting section 5010 is less susceptible to deformation by external forces than the expansion / contraction mechanism 5030. In this embodiment, since the heat conductive member 5008 also functions as the expansion / contraction mechanism 5030, the displacement restricting section 5010 has a larger spring constant than the heat conductive member 5008. As a result, the displacement restricting section 5010 can more reliably restrict displacement in the direction in which the assembly 5002 and the cooling plate 5006 move closer to each other. In this embodiment, the displacement restricting section 5010 is integrally molded with the separator 5014. Therefore, examples of materials that constitute the displacement restricting section 5010 include thermoplastic resins such as polypropylene (PP), polybutylene terephthalate (PBT), polycarbonate (PC), and Noryl® resin (modified PPE). These thermoplastic resins have a larger spring constant than the resin sheet that constitutes the heat conductive member 5008.

[0284] Furthermore, the displacement restricting section 5010 has dimensions perpendicular to the arrangement direction of the assembly 5002 and the cooling plate 5006 that are greater than the dimensions perpendicular to the same direction in the laminated structure of the output terminal 5024, bus bar 5004, heat conduction member 5008 and expansion / contraction mechanism 5030. In this embodiment, as shown in Figure 38, four displacement restricting sections 5010 extend in the X direction, flanking the bus bar 5004 that extends in the X direction at both ends of the assembly 5002 in the Y direction. Each displacement restricting section 5010 extends across multiple batteries 5012. With this configuration, even if the expansion / contraction mechanism 5030 is deformed unevenly, that is, compressed in an inclined manner rather than uniformly in the Z direction, mechanical stress on the laminated structure can be more reliably suppressed. Note that the number of displacement restricting sections 5010 is not particularly limited, and at least one is sufficient.

[0285] Furthermore, the separator 5014 in this embodiment has a projection 5038 on the surface facing the first surface 5020a of the battery 5012 that is in contact with the first surface 5020a. The projection 5038 is located inside the joint 5021 when viewed from the direction of arrangement (direction Z) of the assembly 5002 and the cooling plate 5006. Moreover, the projection 5038 is positioned between the output terminal 5024 and the joint 5021 when viewed from direction Y or direction X. Also, the flat area of ​​the surface of the separator 5014 facing the first surface 5020a where the projection 5038 is not provided is not in contact with the joint 5021. The joint 5021 has a relatively large dimensional tolerance regarding the height of its protrusion from the first surface 5020a. In contrast, by adopting the above structure, the influence of the dimensional tolerance of the joint 5021 can be eliminated, and the dimension H1 of the displacement restricting portion 5010 provided on the separator 5014 can be defined. Therefore, the assembly tolerance of the dimension H1 of the displacement restricting section 5010 can be suppressed. Furthermore, an elastic member that biases the battery 5012 toward the cooling plate 5006 may be provided on the surface of the separator 5014 facing the bottom surface of the outer casing 5020.

[0286] As described above, the battery module 5001 of this embodiment comprises an assembly 5002, a plurality of busbars 5004, a cooling plate 5006, a heat conductive member 5008, and an expansion / contraction mechanism 5030. The assembly 5002 has a structure in which a plurality of batteries 5012, each having a pair of output terminals 5024 arranged on a housing 5019 and the first surface 5020a of the housing 5019, are assembled. The plurality of busbars 5004 electrically connect the output terminals 5024 of the plurality of batteries 5012 to each other. The cooling plate 5006 is arranged to face the first surface 5020a of the housing 5019, with the plurality of busbars 5004 in between. The heat conductive member 5008 is insulating and contacts the busbars 5004 and the cooling plate 5006, thermally connecting the busbars 5004 and the cooling plate 5006.

[0287] The expansion / contraction mechanism 5030 can elastically deform and contract to bias the surface of the heat conduction member 5008 against the bus bar 5004 or the cooling plate 5006, thereby maintaining the thermal connection between the cooling plate 5006 and the bus bar 5004.

[0288] By thermally connecting the cooling plate 5006 to the busbar 5004, the busbar 5004 can be efficiently cooled. This allows for increased capacity of the battery 5012 and battery module 5001 without increasing the size or complexity of the busbar, thereby increasing the heat capacity of the busbar. Furthermore, it prevents the heat generated in the busbar 5004 from being transferred to the battery 5012 and causing its temperature to rise. In addition, the cooling plate 5006 can also cool the output terminal 5024 and electrode body via the busbar 5004. Therefore, the battery 5012 can be efficiently cooled, and a decrease in the power generation performance of the battery module 5001 can be suppressed. Moreover, since the heat dissipation structure of the battery module 5001 other than the cooling plate 5006 can be omitted or reduced, the battery module 5001 can be made smaller and less expensive.

[0289] Furthermore, by providing the expansion / contraction mechanism 5030, dimensional tolerances of each component such as the output terminal 5024, busbar 5004, heat conduction member 5008, and cooling plate 5006 can be absorbed, and the state in which each busbar 5004 and cooling plate 5006 are thermally connected can be maintained more reliably. In addition, the expansion / contraction mechanism 5030 can expand or contract to follow changes in the dimensions of the gap between the assembly 5002 and the cooling plate 5006 when the relative displacement between them changes. Therefore, the state in which the busbar 5004 and the cooling plate 5006 are thermally connected can be maintained. As a result, multiple busbars 5004 can be cooled uniformly, and consequently, multiple batteries 5012 can be cooled uniformly. Thus, according to this embodiment, a decrease in the power generation performance of the battery module 5001 can be suppressed.

[0290] Furthermore, the battery module 5001 includes a displacement restricting section 5010. The displacement restricting section 5010 is interposed between the assembly 5002 and the cooling plate 5006, and the dimensions of the assembly 5002 and the cooling plate 5006 in the alignment direction are less than or equal to the protrusion height from the first surface 5020a in the laminated structure of the output terminal 5024, bus bar 5004, heat conduction member 5008 and expansion / contraction mechanism 5030. The displacement restricting section 5010 contacts both the assembly 5002 and the cooling plate 5006 at least when they are displaced in a direction that brings them closer together.

[0291] In a structure where the cooling plate 5006 is in contact with the busbar 5004, when the assembly 5002 and the cooling plate 5006 are displaced relative to each other due to vibrations input to the battery module 5001 from the outside, there is a risk that a large load will be placed on the output terminal 5024. If the load on the output terminal 5024 becomes excessive, damage to the output terminal 5024 may occur, potentially reducing the power generation performance of the battery 5012. In contrast, in a battery module 5001 in which the terminal forming surface of the battery 5012 and the cooling plate 5006 are arranged facing each other, a displacement restricting part 5010 is provided between the assembly 5002 and the cooling plate 5006, thereby restricting displacement in the direction that brings the assembly 5002 and the cooling plate 5006 closer together. This reduces the load that could be placed on the output terminal 5024 due to the proximity of the assembly 5002 and the cooling plate 5006. Therefore, a decrease in the power generation performance of the battery 5012 can be suppressed.

[0292] Furthermore, the heat conductive member 5008 in this embodiment is elastic, and the expansion / contraction mechanism 5030 is composed of the heat conductive member 5008. In this way, by having the heat conductive member 5008 also function as the expansion / contraction mechanism 5030, the number of parts in the battery module 5001 can be reduced. In addition, the structure of the battery module 5001 can be simplified.

[0293] Furthermore, the dimension H1 of the displacement restricting section 5010 is greater than the sum of the protruding height H3 of the output terminal 5024 and the dimension H4 of the busbar 5004. This allows the load on the output terminal 5024 to be more reliably reduced by the displacement restricting section 5010. In addition, the displacement restricting section 5010 has a larger spring constant than the telescopic mechanism 5030. In other words, the displacement restricting section 5010 has higher rigidity than the telescopic mechanism 5030. This allows the displacement restricting section 5010 to more reliably restrict displacement in the direction that brings the assembly 5002 and the cooling plate 5006 closer together.

[0294] Furthermore, the assembly 5002 has a separator 5014, and the displacement restricting section 5010 is provided on the wall portion 5014a of the separator 5014 that faces the cooling plate 5006. This makes it possible to suppress the increase in the number of parts of the battery module 5001 and the complexity of the manufacturing process that would result from providing the displacement restricting section 5010.

[0295] Furthermore, the battery module 5001 includes a pair of displacement restricting units 5010 positioned on either side of the output terminal 5024. This arrangement of displacement restricting units 5010 makes it possible to more reliably reduce the load on the output terminal 5024.

[0296] (Embodiment 11) Embodiment 11 has the same configuration as Embodiment 10, except that the battery module includes a busbar plate. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 10, while common configurations will be briefly described or omitted. Figure 42 is a perspective view of the battery module according to Embodiment 11. Note that Figure 42 shows the cooling plate in a disassembled state.

[0297] The battery module 5001 comprises an assembly 5002, a plurality of busbars 5004, a cooling plate 5006, a heat conductive member 5008, a displacement restricting section 5010, and an expansion / contraction mechanism 5030. The expansion / contraction mechanism 5030 is composed of an elastic heat conductive member 5008. The assembly 5002 has a plurality of batteries 5012, a pair of end plates 5016, a pair of bind bars 5018, and a busbar plate 5032.

[0298] The busbar plate 5032 is a plate-shaped member that is positioned opposite the first surface 5020a on which the output terminals 5024 of the multiple batteries 5012 are provided, and covers the first surface 5020a. For example, the busbar plate 5032 is fixed to the end plate 5016, etc., by fastening members (not shown). Alternatively, the busbar plate 5032 may be fixed by being gripped by a pair of end plates 5016 or a pair of bind bars 5018. In Embodiment 10, the busbar plate 5032 corresponds to the collection of wall portions 5014a provided by each separator 5014. Flat separators (not shown) are placed between adjacent batteries 5012 and between the batteries 5012 and the end plates 5016.

[0299] The busbar plate 5032 has an opening 5032a at a position corresponding to the safety valve 5026 of the battery 5012, allowing the safety valve 5026 to be exposed to the outside. The busbar plate 5032 also has an opening (not shown) at a position corresponding to the output terminal 5024 of the battery 5012, allowing the output terminal 5024 to be exposed to the outside. Multiple busbars 5004 are mounted on and supported by the busbar plate 5032.

[0300] The displacement restricting portion 5010 is provided on the surface of the busbar plate 5032 facing the cooling plate 5006. In other words, the displacement restricting portion 5010 is composed of a protrusion that extends from the main surface of the busbar plate 5032 toward the cooling plate 5006. Specifically, a pair of displacement restricting portions 5010 are provided at both ends of the opening in the busbar plate 5032 for exposing the output terminal 5024. Therefore, a pair of displacement restricting portions 5010 are arranged on either side of the output terminal 5024.

[0301] The battery module 5001 according to this embodiment can also suppress the decrease in power generation performance of the battery module 5001, similar to the case of embodiment 10.

[0302] (Embodiment 12) Embodiment 12 has a configuration common to Embodiment 10, except that the structure of the telescopic mechanism 5030 is different. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 10, and the common configurations will be briefly described or omitted. Figure 43 is a schematic cross-sectional view showing a battery module according to Embodiment 12. In Figure 43, the internal structure of the battery 5012 and cooling plate 5006, the separator 5014, and the bind bar 5018 are not shown.

[0303] The battery module 5001 comprises an assembly 5002, a plurality of busbars 5004, a cooling plate 5006, a heat conduction member 5008, a displacement restricting section 5010, and an expansion / contraction mechanism 5030. The assembly 5002 has a plurality of batteries 5012, a plurality of separators 5014, a pair of end plates 5016, and a pair of bind bars 5018.

[0304] Furthermore, the battery module 5001 of this embodiment includes a spring member 5034 interposed between the output terminal 5024 and the busbar 5004. The telescopic mechanism 5030 is composed of the spring member 5034. The spring member 5034 is electrically conductive. Therefore, the output terminal 5024 and the busbar 5004 are electrically connected via the spring member 5034. Known springs such as coil springs and leaf springs can be used as the spring member 5034. The spring member 5034 is fixed to either the output terminal 5024 or the busbar 5004, or both. Examples of fixing methods include welding and fixing with adhesive. Alternatively, the spring member 5034 and the busbar 5004 may be integrally configured by bending a part of the busbar 5004 to provide a spring structure to the busbar 5004.

[0305] When the battery module 5001 is assembled, the spring member 5034 is elastically deformed by being sandwiched between the bus bar 5004 and the output terminal 5024, allowing it to be compressed. The amount of compression of the spring member 5034 varies depending on the size of the gap between the bus bar 5004 and the output terminal 5024. Therefore, tolerances of each component can be absorbed by the spring member 5034.

[0306] The spring member 5034, when compressed, can press the busbar 5004 against the heat conduction member 5008. This allows the surface of the heat conduction member 5008 to be biased against both the busbar 5004 and the cooling plate 5006. In this way, the heat conduction member 5008 is pressed against both the busbar 5004 and the cooling plate 5006, thereby maintaining the thermal connection between the cooling plate 5006 and the busbar 5004. The dimensions of the spring member 5034 in the alignment direction of the assembly 5002 and the cooling plate 5006 are set to be sufficiently large to reliably absorb the tolerances of each member and maintain the thermal connection between the cooling plate 5006 and the busbar 5004.

[0307] In this embodiment, the displacement restricting section 5010 is constructed separately from the separator 5014. However, the configuration is not limited to this, and the displacement restricting section 5010 may be integrally molded with the separator 5014, similar to embodiment 10.

[0308] The battery module 5001 according to this embodiment can also suppress the decrease in power generation performance of the battery module 5001, similar to the case of embodiment 10.

[0309] (Embodiment 13) Embodiment 13 has the same configuration as Embodiment 10, except that the battery module further comprises an adhesive layer. Hereinafter, this embodiment will be described focusing on the configurations that differ from Embodiment 10, while common configurations will be briefly described or omitted. Figure 44 is a schematic cross-sectional view of the battery module according to Embodiment 13. Figure 44 omits the illustration of the internal structure of the battery 5012 and cooling plate 5006, the separator 5014, and the bind bar 5018.

[0310] The battery module 5001 comprises an assembly 5002, a plurality of busbars 5004, a cooling plate 5006, a heat conductive member 5008, a displacement restricting section 5010, and an expansion / contraction mechanism 5030. The expansion / contraction mechanism 5030 is composed of an elastic heat conductive member 5008. The assembly 5002 has a plurality of batteries 5012, a plurality of separators 5014, a pair of end plates 5016, and a pair of bind bars 5018.

[0311] Furthermore, the battery module 5001 of this embodiment includes a conductive adhesive layer 5036 that fixes the output terminal 5024 and the busbar 5004. An example of a conductive adhesive constituting the adhesive layer 5036 is an epoxy resin mixed with a conductive material filler such as silver (Ag). The adhesive layer 5036 is interposed between the output terminal 5024 and the busbar 5004 and is in contact with both of them. Therefore, the output terminal 5024 and the busbar 5004 are electrically connected via the adhesive layer 5036.

[0312] In this embodiment, the output terminal 5024 has a protrusion 5024c that projects toward the cooling plate 5006. The tip of the protrusion 5024c is embedded in the adhesive layer 5036. Therefore, the output terminal 5024 contacts the adhesive layer 5036 at the tip surface and side surface of the protrusion 5024c. This increases the contact area between the output terminal 5024 and the adhesive layer 5036. As a result, the output terminal 5024 and the busbar 5004 can be fixed more securely. Furthermore, the output terminal 5024 and the busbar 5004 can be electrically connected more securely. Note that the output terminal 5024 may be elongated in shape, extending toward the cooling plate 5006. In this case as well, it is easier to bring the tip surface and side surface of the output terminal 5024 into contact with the adhesive layer 5036.

[0313] The adhesive layer 5036 is formed, for example, as follows: With the uncured adhesive applied to the surface of the busbar 5004, the output terminal 5024 is inserted into the adhesive. Alternatively, with the uncured adhesive applied to the tip of the output terminal 5024, the busbar 5004 is pressed against the adhesive. By curing the adhesive in this state, the adhesive layer 5036 is formed, and the output terminal 5024 and the busbar 5004 are fixed together by the adhesive layer 5036.

[0314] Preferably, the busbar 5004 has a recess or a groove extending in the longitudinal direction of the busbar 5004. This allows adhesive to be applied to the recess or groove of the busbar 5004, and the adhesive can be more securely fixed in the desired position during the assembly of the battery module 5001. As a result, the manufacturing process of the battery module 5001 can be simplified.

[0315] In this embodiment, the displacement restricting section 5010 is constructed separately from the separator 5014. However, the configuration is not limited to this, and the displacement restricting section 5010 may be integrally molded with the separator 5014, similar to embodiment 10.

[0316] The battery module 5001 according to this embodiment can also suppress the decrease in power generation performance of the battery module 5001, similar to embodiment 10. Furthermore, in this embodiment, dimensional tolerances of each component can be absorbed not only by the heat conductive member 5008 but also by the adhesive layer 5036. Therefore, the adhesive layer 5036 constitutes part of the expansion and contraction mechanism 5030. This allows for better thermal connection between the busbar 5004 and the cooling plate 5006.

[0317] Furthermore, since the adhesive layer 5036 can absorb the dimensional tolerances of each component, the amount of shrinkage of each heat conduction member 5008 can be made uniform when the battery module 5001 is assembled. This makes it possible to uniformize the thermal connection state between each bus bar 5004 and the cooling plate 5006, and allows the entire battery module 5001 to be cooled more evenly.

[0318] The number of batteries 5012 and the number of heat conductive members 5008 in the assembly 5002 are not particularly limited. The structure of each part of the assembly 5002, including the shape of the separator 5014 and the fastening structure between the end plate 5016 and the bind bar 5018, is also not particularly limited. [Explanation of Symbols]

[0319] 1 Battery pack, 20,120,220,320,420 Battery module, 21 Battery group, 31 Battery, 40,240 Busbar, 40a Metal part (main body), 40b Insulation part, 42,43 Output terminals, 45 First surface, 46 Orthogonal surface, 50,150,250,350,450 Cooling plate, 50a Flat plate part, 50b First surface contact part, 51 Passage, 61 Electrode body, 62 Outer casing, 63 Lid, 241 Protrusion (first locking part), 253 Hole (second locking part), 455 Orthogonal surface contact part, 2001 Battery module, 2002 Assembly, 2004 Cooling plate, 2006 Battery, 2014 Output terminal, 2016 Busbar, 2020 Housing 2020a First surface, 2022 Valve section, 2024 Electrode body, 2032 Current collector section, 2040 Electrode plate, 2050 Spacer, 52 Wall section, 4001 Battery module, 4002 Assembly, 4004 Busbar, 4006 Cooling plate, 4006a First main surface, 4006b Second main surface, 4012 Battery, 4019 Housing, 4020a First surface, 4024 Output terminal, 4026 Valve section, 4030 Gas induction section, 4032 Gas flow section, 4040 Thin-walled section, 4042 First bottomed hole, 4044 Second bottomed hole, 4048 Flange section, 4050 Stepped section, 5001 Battery module, 5002 Assembly, 5004 Busbar, 5006 Cooling plate, 5008 Heat conduction member, 5010 Displacement restricting section, 5012 Battery, 5014 Separator, 5020 Outer casing, 5020a First surface, 5024 Output terminal, 5030 Telescopic mechanism, 5032 Busbar plate, 5034 Spring member, 5036 Adhesive layer.

Claims

[Claim 1] Multiple batteries, The system comprises one or more busbars that electrically connect each of the aforementioned multiple batteries, The aforementioned multiple batteries are Electrode body and A housing for housing the electrode body, A pair of output terminals are electrically connected to the electrode body and are located on the first surface of the housing, The first surface comprises a valve portion, Of the pair of output terminals, one output terminal is connected to the busbar. In the vertical direction, the first surface is located below the plurality of batteries. Battery module.

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