Battery Module

Abstract

According to the embodiments, a battery module comprises a battery group, an electrical path, a case, an insulating layer, and a conductive layer. The battery group comprises a plurality of batteries, and current flows through the electrical path when the plurality of batteries are charged and discharged. The battery group is housed inside the case, and the case comprises a conductive metal body. The insulating layer is electrically insulating and is layered on the surface of the metal body on the side on which the battery group is located. The conductive layer is layered on the surface of the insulating layer on the side on which the battery group is located and is electrically connected to any conductive portion the electrical path and the battery group.

Description

[Technical field]

[0001] SUMMARY OF THE DISCLOSURE An embodiment of the present invention relates to a battery module. [Background technology]

[0002] In a battery module, a battery group including a plurality of batteries (single cells) is housed inside a case. Some battery modules are provided with a metal body in the case to improve the transferability of heat generated in the battery group to the outside, and the heat is dissipated from the metal body to the outside of the battery module. In such battery modules, an insulating material is provided between the plurality of batteries forming the battery group and the metal body, for example, to electrically insulate the battery group from the metal body.

[0003] In the battery module as described above, it is required to effectively suppress the occurrence of corona discharge in the air layer between the battery group and the metal body. It is also required to suppress the corona discharge without increasing the labor required for manufacturing the battery module. Therefore, it is required to effectively suppress the corona discharge in the air layer between the battery group and the metal body with a simple configuration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-163740 [Patent Document 2] Japanese Patent Publication No. 2014-216113 [Patent Document 3] Japanese Patent Application Publication No. 2013-164975 Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a battery module that can effectively suppress corona discharge in the air layer between a battery group and a metal body with a simple configuration. [Means for solving the problem]

[0006] According to an embodiment, the battery module includes a battery group, an electrical path, a case, an insulating layer, 、 Conductive Layer and insulator The battery group includes a plurality of batteries, and a current flows through the electrical path when the plurality of batteries are charged and discharged. The battery group is housed inside a case, and the case includes a conductive metal body. The metal body serves as a heat sink that dissipates heat to the outside. The insulating layer is laminated on the surface of the metal body on the side where the battery group is located, and has electrical insulation properties. The conductive layer is laminated on the surface of the insulating layer on the side where the battery group is located, and is electrically connected to either the electrical path or a conductive portion of the battery group. The conductive layer has a potential that is the same as any position in the electrical path and different from that of the metallic body. The insulator is provided between the conductive layer and the battery group and has electrical insulation properties. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a perspective view that illustrates an example of a single battery used in a battery module according to an embodiment. [Diagram 2] FIG. 2 is a perspective view showing the battery module according to the first embodiment. [Diagram 3] FIG. 3 is a perspective view showing the battery module according to the first embodiment disassembled into its individual members. [Figure 4] FIG. 4 is a cross-sectional view that illustrates the battery module according to the first embodiment, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. [Diagram 5] FIG. 5 is a cross-sectional view that illustrates a battery module according to a first modified example, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. [Figure 6] FIG. 6 is a cross-sectional view that illustrates a battery module according to a second modified example, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. [Figure 7]FIG. 7 is a cross-sectional view that illustrates a battery module according to a third modified example, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. [Figure 8] FIG. 8 is a cross-sectional view that illustrates a battery module according to a fourth modified example, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. [Figure 9] FIG. 9 is a schematic diagram showing a conductive layer of a battery module according to a fifth modified example, viewed from one side in the stacking direction of the insulating layers and the conductive layers. [Figure 10] FIG. 10 is a cross-sectional view that illustrates a battery module according to a sixth modified example, taken along a cross section perpendicular or substantially perpendicular to the lateral direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described with reference to the drawings.

[0009] The battery module according to the embodiment includes a battery group including a plurality of batteries (single cells) and a case that the battery group is housed in. The batteries that make up the battery group are, for example, secondary batteries such as lithium ion secondary batteries.

[0010] [battery] First, the battery (single cell) will be described. FIG. 1 shows an example of a single battery 1. The battery 1 includes an electrode group 2 and an outer container 3 in which the electrode group 2 is housed. In the example shown in FIG. 1, etc., the outer container 3 is made of a metal such as aluminum, an aluminum alloy, iron, or stainless steel. The outer container 3 includes a container body 5 and a lid 6. Here, the battery 1 and the outer container 3 are regulated in a depth direction (direction indicated by arrows X1 and X2), a lateral direction (direction indicated by arrows Y1 and Y2) intersecting (perpendicular or substantially perpendicular) with respect to the depth direction, and a height direction (direction indicated by arrows Z1 and Z2) intersecting (perpendicular or substantially perpendicular) with respect to both the depth direction and the lateral direction. In the example shown in FIG. 1, etc., the dimension in the depth direction is much smaller than the dimension in the lateral direction and the dimension in the height direction in each of the battery 1 and the outer container 3.

[0011] The container body 5 includes a bottom wall 7 and a peripheral wall 8. An internal cavity 10 in which the electrode group 2 is housed is defined by the bottom wall 7 and the peripheral wall 8. In the battery 1, the internal cavity 10 opens toward the side opposite to the side on which the bottom wall 7 is located in the height direction. The peripheral wall 8 surrounds the internal cavity 10 over the entire circumference in the circumferential direction. The lid 6 is attached to the container body 5 at the opening of the internal cavity 10. Therefore, the lid 6 is attached to the peripheral wall 8 at the end opposite to the bottom wall 7. The lid 6 and the bottom wall 7 face each other in the height direction with the internal cavity 10 in between.

[0012] The electrode group 2 includes a positive electrode and a negative electrode (neither of which is shown in the figure). In addition, a separator (not shown in the figure) is interposed between the positive electrode and the negative electrode in the electrode group 2. The separator is made of an electrically insulating material and electrically insulates the positive electrode from the negative electrode.

[0013] The positive electrode comprises a positive electrode current collector such as a positive electrode current collector foil, and a positive electrode active material-containing layer supported on the surface of the positive electrode current collector. The positive electrode current collector is, but is not limited to, for example, an aluminum foil or an aluminum alloy foil, and has a thickness of about 5 μm to 20 μm. The positive electrode active material-containing layer comprises a positive electrode active material, and may optionally contain a binder and a conductive agent. Examples of the positive electrode active material include, but are not limited to, oxides, sulfides, and polymers that can absorb and release lithium ions. The positive electrode current collector comprises a positive electrode current collector tab as a portion not supported by the positive electrode active material-containing layer.

[0014] The negative electrode comprises a negative electrode current collector such as a negative electrode current collector foil, and a negative electrode active material-containing layer (not shown) supported on the surface of the negative electrode current collector. The negative electrode current collector is, but is not limited to, for example, an aluminum foil, an aluminum alloy foil, or a copper foil, and has a thickness of about 5 μm to 20 μm. The negative electrode active material-containing layer comprises a negative electrode active material, and may optionally contain a binder and a conductive agent. The negative electrode active material is, but is not limited to, a metal oxide, a metal sulfide, a metal nitride, a carbon material, and the like, which can occlude and release lithium ions. The negative electrode current collector comprises a negative electrode current collector tab as a portion not supported by the negative electrode active material-containing layer.

[0015] In the electrode group 2, a pair of current collecting tabs is formed by the positive electrode current collecting tab and the negative electrode current collecting tab. In the electrode group 2, a pair of current collecting tabs protrude. In one example, in the electrode group 2, the positive electrode current collecting tab protrudes to one side in the lateral direction of the battery 1, and the negative electrode current collecting tab protrudes to the side opposite to the side from which the positive electrode current collecting tab protrudes in the lateral direction of the battery 1. In another example, in the electrode group 2, each of the pair of current collecting tabs protrudes toward the side where the lid 6 is located in the height direction of the battery 1. In this case, the pair of current collecting tabs are located apart from each other in the lateral direction of the battery 1.

[0016] In addition, in the internal cavity 10, the electrode group 2 is retained (impregnated) with an electrolytic solution (not shown). The electrolytic solution may be a non-aqueous electrolytic solution in which an electrolyte is dissolved in an organic solvent, or may be an aqueous electrolytic solution such as an aqueous solution. Instead of the electrolytic solution, a gel electrolyte or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte may be interposed between the positive electrode and the negative electrode in the electrode group instead of a separator. In this case, the positive electrode is electrically insulated from the negative electrode by the solid electrolyte.

[0017] In the battery 1, a pair of electrode terminals 11 are attached to the outer surface (upper surface) of the lid 6 of the outer container 3. The electrode terminals 11 are made of a conductive material such as metal. One of the electrode terminals 11 is a positive electrode terminal of the battery 1, and the other electrode terminal 11 is a negative electrode terminal of the battery 1. An insulating member 12 is provided between each of the electrode terminals 11 and the lid 6. Each of the electrode terminals 11 is electrically insulated from the outer container 3 including the lid 6 by the insulating member 12.

[0018] The positive electrode current collecting tab of the electrode group 2 is electrically connected to a positive electrode terminal, which is one of the corresponding electrode terminals 11, via one or more leads (positive electrode side leads). In addition, the negative electrode current collecting tab of the electrode group 2 is electrically connected to a negative electrode terminal, which is one of the corresponding electrode terminals 11, via one or more leads (negative electrode side leads). Each of the leads is formed of a conductive material such as metal. In the internal cavity 10 of the outer container 3, each of the pair of current collecting tabs and leads is electrically insulated from the outer container 3 (container body 5 and lid 6) by one or more insulating members (not shown).

[0019] In the example shown in FIG. 1, the gas release valve 13 and the liquid inlet are formed in the lid 6. Then, a sealing plate 15 for closing the liquid inlet is welded to the outer surface of the lid 6. The gas release valve 13 and the liquid inlet may not be provided in the battery. During charging and discharging of the battery 1 as described above, the outer container 3 may have a potential between the potentials of the pair of electrode terminals 11 due to conduction via the electrolyte. That is, during charging and discharging of the battery 1, the outer container 3 may have a potential between the potential of the positive electrode terminal (positive electrode potential) and the potential of the negative electrode terminal (negative electrode potential).

[0020] Furthermore, the configuration of the battery (single cell) is not limited to the example shown in Fig. 1. In one example, the exterior of the battery may be formed from a laminate film. In this case, in the exterior of the battery, a metal layer is sandwiched between two insulating layers having electrical insulation properties, and the outer surface of the exterior is formed by one of the two insulating layers. Then, an electrode group is housed inside the exterior formed from the laminate film.

[0021] [Battery module] The battery module will be described below. The battery module includes a battery group, and the battery group includes a plurality of batteries (single cells). In one example, each of the plurality of batteries that make up the battery group has the same configuration as the battery 1 described above.

[0022] (First embodiment) A first embodiment of the battery module will be described below. Fig. 2 to Fig. 4 show a battery module 20 of this embodiment. As shown in Fig. 2 to Fig. 4 etc., the battery module 20 includes a battery group 21 and a case 22 in which the battery group 21 is housed. The case 22 defines a housing space 23 for the battery group 21. The battery group 21 includes a plurality of batteries (single cells) 1 as described above, and in the battery group 21, the plurality of batteries 1 are electrically connected via a bus bar 25. The bus bar 25 is formed from a conductive material. In the battery group 21, at least one of a series connection structure in which the plurality of batteries 1 are electrically connected in series and a parallel connection structure in which the plurality of batteries 1 are electrically connected in parallel is formed.

[0023] Here, in the battery module 20 including the battery group 21 and the case 22, a depth direction (direction indicated by arrows X3 and X4), a lateral direction (direction indicated by arrows Y3 and Y4) intersecting (orthogonal or nearly orthogonal) with the depth direction, and a height direction (direction indicated by arrows Z3 and Z4) intersecting (orthogonal or nearly orthogonal) with both the depth direction and the lateral direction are defined. Fig. 2 is a perspective view, and Fig. 3 is a perspective view showing each component disassembled. Fig. 4 shows a cross section perpendicular or nearly orthogonal to the lateral direction.

[0024] The case 22 is formed from a plurality of members including a frame member 26 and a metal body 27. In FIG. 2, only the frame member 26 of the case 22 is shown, and in FIG. 3, only the frame member 26 and the metal body 27 of the case 22 are shown. The metal body 27 is formed from aluminum or an aluminum alloy or the like and has electrical conductivity. The portions of the case 22, such as the frame member 26, other than the metal body 27 are formed from a material having electrical insulation. Examples of materials forming the portions of the case 22 other than the metal body 27 include resins such as polyphenylene ether, polycarbonate, and polybutylene terephthalate.

[0025] The case 22 includes a case top wall (case upper wall) 31 and two pairs of case side walls 32, 33. The case top wall 31 is adjacent to the storage space 23 from one side in the height direction (the side indicated by the arrow Z3). In the battery module 20, the two pairs of case side walls 32, 33 form a case peripheral wall that surrounds the storage space 23 over the entire circumference in the circumferential direction. The frame member 26 of the case 22 includes a frame bottom 35. In the case 22, the case top wall 31 and the frame bottom 35 face each other with the storage space 23 between them in the height direction. Each of the case side walls 32, 33 is provided between the case top wall 31 and the frame bottom 35 and extends along the height direction. The pair of case side walls 32 face each other with the storage space 23 between them in the lateral direction. The pair of case side walls 33 face each other with the storage space 23 between them in the depth direction. Each of the case side walls 32 extends along the depth direction between the case side walls 33. Each of the case side walls 33 extends along the lateral direction between the case side walls 32.

[0026] The case 22 also includes two partition walls 36. The partition walls 36 are disposed between the pair of case side walls 32 in the horizontal direction and spaced apart from each other in the horizontal direction. Each of the partition walls 36 is disposed apart from each of the case side walls 32 in the horizontal direction. Each of the partition walls 36 extends along the height direction between the case top wall 31 and the frame bottom 35. Each of the partition walls 36 extends along the depth direction between the case side walls 33. Since the two partition walls 36 are formed as described above, in the example of FIG. 2 and FIG. 3, the storage space 23 of the battery group 21 is partitioned into three regions 37 by the partition walls 36. That is, the storage space 23 is divided into three in the horizontal direction by the partition walls 36.

[0027] The frame bottom 35 supports the battery group 21 from the opposite side to the case top wall 31 in the height direction. Three through holes 38 are formed in the frame bottom 35. In the frame bottom 35, each of the through holes 38 is formed at a position corresponding to one of the regions 37. Each of the regions 37 of the storage space 23 opens to the outside of the frame member 26 through a corresponding one of the through holes 38. In two of the three regions 37 located at both ends in the horizontal direction, the frame bottom 35 protrudes inward from each of the case side walls 32, 33 and the partition wall 36, and the protruding end of the frame bottom 35 forms the edge of the through hole 38. In one of the three regions 37 located in the middle in the horizontal direction, the frame bottom 35 protrudes inward from each of the case side walls 33 and the partition wall 36, and the protruding end of the frame bottom 35 forms the edge of the through hole 38. Therefore, in each of the regions 37, the frame bottom 35 is formed so as to protrude inwardly around the entire circumference, and in each of the through holes 38, the protruding end of the frame bottom 35 forms a rim around the entire circumference.

[0028] In this embodiment, the battery group 21 forms three battery columns 41. Each of the battery columns 41 is disposed in a corresponding one of the regions 37 in the storage space 23. Adjacent battery columns 41 in the lateral direction of the battery module 20 are separated by a partition wall 36. In the battery columns 41, a plurality of batteries 1 are arranged, and in the example shown in Figs. 2 and 3, eight batteries 1 are arranged in each of the battery columns 41. In each of the battery columns 41, the batteries 1 are arranged such that the arrangement direction of the batteries 1 coincides or nearly coincides with the depth direction of the battery module 20 (case 22). In each of the three regions 37, the battery columns 41 are supported by a protruding portion of the frame bottom 35 protruding toward the inner periphery.

[0029] In the battery group 21 (each of the battery strings 41), the depth direction of each of the batteries 1 coincides or approximately coincides with the depth direction of the battery module 20 (case 22), and the lateral direction of each of the batteries 1 coincides or approximately coincides with the lateral direction of the battery module 20. In the battery group 21, the height direction of each of the batteries 1 coincides or approximately coincides with the height direction of the battery module 20. Each of the batteries 1 is arranged in the storage space 23 with the outer surface of the bottom wall 7 facing the side where the frame bottom 35 is located, and the outer surface of the lid 6 facing the side where the case top wall 31 is located. In each of the battery strings 41, the multiple batteries 1 are arranged with no or almost no misalignment with each other in the lateral and height directions of the battery module 20. The three battery strings 41 are arranged with no or almost no misalignment with each other in the vertical and height directions of the battery module 20.

[0030] In each of the battery rows 41 of the battery group 21, a partition plate (separator) 42 is provided between adjacent batteries 1 in the arrangement direction (depth direction of the battery module 20). Each of the battery rows 41 is provided with one or more partition plates 42, and in the example shown in Figs. 2 to 4, etc., seven partition plates 42 are provided in each of the battery rows 41. Each of the partition plates 42 is formed from a material having at least an outer surface with electrical insulation. Examples of materials forming at least the outer surface of the partition plate 42 include electrically insulating resins such as polyphenylene ether (PPE), polycarbonate (PC), and polybutylene terephthalate (PBT).

[0031] The metal body 27 forms a part of the case bottom wall of the case 22 and also forms a part of the outer surface of the case 22. The metal body 27 serves as a heat dissipation body that dissipates heat generated in the battery group 21 to the outside of the battery module 20. The metal body 27 has higher thermal conductivity than other parts of the case 22 other than the metal body 27. The metal body 27 is attached to the frame member 26 from the opposite side to the side where the case top wall 31 is located in the height direction of the battery module 20. In this embodiment, the metal body 27 is located on the opposite side to the side where the case top wall 31 is located with respect to the battery group 21 (the plurality of batteries 1). The metal body 27 is formed to appropriate dimensions and shapes as necessary, and in one example, is formed to be flat or approximately flat with a thickness of about 0.5 mm to 5 mm.

[0032] Moreover, in this embodiment, the battery module 20 includes three insulating sheets (insulators) 43. Each of the insulating sheets 43 has electrical insulation properties and has higher thermal conductivity than the air and the parts of the case 22 other than the metal body 27. Each of the insulating sheets 43 preferably has plasticity. Examples of materials for forming each of the insulating sheets 43 include resins having electrical insulation properties and plasticity, such as silicone. However, each of the insulating sheets 43 has lower thermal conductivity than the metal body 27. Each of the insulating sheets 43 is sandwiched between the battery group 21 and the metal body 27 in the height direction of the battery module 20.

[0033] Each of the insulating sheets 43 is disposed in a corresponding one of the regions 37 in the storage space 23. Each of the insulating sheets 43 adheres to and abuts on a corresponding one of the battery rows 41 in the corresponding one of the regions 37. In each of the battery rows 41, the corresponding one of the insulating sheets 43 adheres to and abuts on the outer container 3 (bottom wall 7) of each of the batteries 1 from the side where the metal body 27 is located in the height direction of the battery module 20. In each of the battery rows 41, a part of the bottom wall 7 of the outer container 3 of each of the batteries 1 abuts on the frame bottom 35 or is bonded to the frame bottom 35 via an adhesive or the like. As a result, each of the battery rows 41 is supported by a protruding portion toward the inner periphery of the frame bottom 35. In each of the batteries 1 in the battery row 41, the corresponding one of the insulating sheets 43 adheres to and abuts on a part of the bottom wall 7 of the outer container 3 other than the abutting portion and the bonded portion to the frame bottom 35.

[0034] Moreover, each of the insulating sheets 43 is inserted into a corresponding one of the through holes 38. In each of the through holes 38, a small gap may be formed during manufacturing between the insulating sheet 43 placed therein and the protruding end of the frame bottom 35. In this case, the gap formed in each of the through holes 38 between the insulating sheet 43 and the protruding end of the frame bottom 35 becomes an air layer between the battery group 21 and the metal body 27.

[0035] In the battery module 20, an insulating layer 45 is laminated on the surface of the metal body 27 on the side where the battery group 21 is located. The insulating layer 45 is formed between the metal body 27 and each of the insulating sheet 43 and the frame bottom 35 in the height direction of the battery module 20. The insulating layer 45 has electrical insulation properties. The insulating layer 45 is, for example, an epoxy resin film or the like, and is formed from a resin having electrical insulation properties. In the battery module 20 of this embodiment, a conductive layer 46 is laminated on the surface of the insulating layer 45 on the side where the battery group 21 is located. The conductive layer 46 is formed between the insulating layer 45 and each of the insulating sheet 43 and the frame bottom 35 in the height direction of the battery module 20. The conductive layer 46 is formed from a metal having electrical conductivity, such as copper or a copper alloy. Therefore, in the battery module 20, the metal body 27, the insulating layer 45, and the conductive layer 46 are laminated in this order from the side farthest from the battery group 21.

[0036] The insulating layer 45 adheres to the metal body 27, and there is no air (air layer) between the insulating layer 45 and the metal body 27, or there is almost no air (air layer) between the insulating layer 45 and the conductive layer 46. The conductive layer 46 adheres to the insulating layer 45, and there is no air (air layer) between the insulating layer 45 and the conductive layer 46, or there is almost no air (air layer) between the insulating layer 45 and the conductive layer 46. The metal body 27 is electrically insulated from the conductive layer 46 by the insulating layer 45. Note that the insulating layer 45 and the conductive layer 46 are omitted in FIG. 3. Also, in FIG. 4, for the sake of explanation, the thicknesses (dimensions in the stacking direction) of the insulating layer 45 and the conductive layer 46 are shown to be approximately the same as the thickness of the metal body 27 (dimensions in the stacking direction), but the thicknesses of the insulating layer 45 and the conductive layer 46 are far smaller than the thickness of the metal body 27.

[0037] In this embodiment, the insulating layer 45 and the conductive layer 46 are integrally formed with the metal body 27. In one example, a metal base substrate such as an aluminum base substrate used for forming a printed wiring board is used as a substrate on which the metal body 27, the insulating layer 45, and the conductive layer 46 are integrally formed. In another example, an insulating sheet and a metal sheet are laminated in this order on the surface of the metal body, and the insulating sheet and the metal sheet are pressed against the metal body by pressure in a high temperature environment, thereby forming the metal body 27, the insulating layer 45, and the conductive layer 46 integrally. In either case, the metal body 27, the insulating layer 45, and the conductive layer 46 are integrally formed in a state in which there is no or almost no air between the insulating layer 45 and the metal body 27 and between the insulating layer 45 and the conductive layer 46.

[0038] Furthermore, the insulating layer 45 extends beyond the edge of the conductive layer 46 to a region outside the edge of the conductive layer 46 in a direction intersecting (orthogonal or substantially orthogonal) the stacking direction of the insulating layer 45 and the conductive layer 46. In one example such as Fig. 4, the insulating layer 45 extends to the outer edge of the metal body 27. In this embodiment, the insulating layer 45 extends beyond the edge of the conductive layer 46 to a region outside the edge of the conductive layer 46 in both the depth direction and the lateral direction of the battery module 20.

[0039] In this embodiment, the frame bottom 35 abuts against the conductive layer 46 from the side where the battery group 21 is located in the height direction. Each of the insulating sheets 43 is in close contact with and abuts against the conductive layer 46 from the side where the battery group 21 is located in the height direction of the battery module 20. In this embodiment, the battery group 21 is electrically insulated from the metal body 27 by the insulating layer 45 or the like. Due to the above-mentioned configuration, in the battery module 20, each of the insulating sheets 43 and the frame bottom 35 is sandwiched between the metal body 27 on which the insulating layer 45 and the conductive layer 46 are laminated and the battery group 21 in the height direction of the battery module 20.

[0040] Furthermore, in the battery module 20, heat generated in each of the battery strings 41 is transferred to the metal body 27 through a corresponding one of the insulating sheets 43, the conductive layer 46, and the insulating layer 45 in that order. Therefore, the insulating sheet 43 and the like form a heat transfer path from the battery group 21 to the metal body 27 that does not pass through an air layer. The heat transferred to the metal body 27 is then dissipated from the metal body 27 to the outside of the battery module 20.

[0041] The battery module 20 is used in a state in which it is placed on, for example, a metal base (cooling plate). In this case, the battery module 20 is placed on the base with the base adjacent to the metal body 27 from the side opposite to the battery group 21. In addition, the heat transferred from the battery group 21 to the metal body 27 as described above is dissipated from the metal body 27 to the base.

[0042] The battery module 20 is used, for example, as a stationary power source or a power source for railway vehicles. Here, when the battery module 20 is used as a power source for railways, in a battery system in which the battery module 20 is used, a plurality of battery modules including the battery module 20 are electrically connected in series. For this reason, in the battery system, a large number of batteries are connected in series, and when the battery module 20 is charged and discharged, heat is generated in the battery group 21. Therefore, the battery module 20 is required to have high cooling performance. In such a case, forced cooling may be performed by providing a flow path through which a cooling fluid including a cooling liquid or a cooling gas flows inside a base (cooling plate) on which the battery module 20 is placed.

[0043] In the battery module 20, the battery group 21 composed of the multiple batteries 1 includes a pair of external terminals (not shown), and an electrical path 47 is formed between the pair of external terminals. A current flows through the electrical path 47 when the multiple batteries 1 constituting the battery group 21 are charged and discharged. The electrical path 47 is formed by the electrode groups 2 of the multiple batteries 1, the electrode terminals 11 of the multiple batteries 1, the bus bar 25, and the like. When the battery module 20 is used as a power source for a railway, the multiple battery modules including the battery module 20 are electrically connected in series as described above. In this case, the electrical path 47 of the battery module 20 forms a part of a main circuit through which a current flows through the multiple battery modules 20.

[0044] The battery module 20 also includes a monitoring board 48. A detection circuit and the like are formed on the monitoring board 48, and the detection circuit and the like of the monitoring board 48 are electrically connected to the electrical path 47. In one example such as FIG. 4 , the monitoring board 48 is connected to one or more of the bus bars 25 via a screw or the like, so that the detection circuit and the like of the monitoring board 48 are electrically connected to the electrical path 47. Note that the connection between each of the one or more bus bars 25 and the monitoring board 48 is not limited to a configuration in which they are connected by a screw, and may be a configuration in which they are connected by soldering or a connector or the like. The detection circuit of the monitoring board 48 detects any one of the voltage of the entire battery group 21, the voltage of one or more of the plurality of batteries 1, the temperature of one or more of the plurality of batteries 1, and the current flowing through the electrical path 47.

[0045] The battery module 20 also includes a relay conductive part 50 made of a conductive material. The relay conductive part 50 is connected to the conductive layer 46 at a connection position 51, and is connected to one of the bus bars 25 at a connection position 52. Thus, the relay conductive part 50 connects between the conductive layer 46 and one of the bus bars 25, and relays between the conductive layer 46 and one of the bus bars 25. As a result, the conductive layer 46 is electrically connected to one of the bus bars 25, and is electrically connected to the electrical path 47. In one example shown in FIG. 4, the relay conductive part 50 extends from the connection position 51 to the connection position 52 in the height direction toward the side where the case top wall 31 is located. The relay conductive part 50 also extends through a region between one of the case side walls 33 and a battery 1 disposed at one end of one battery string 41.

[0046] The relay conductive part 50 is covered by an insulating part 53 from the side where the storage space 23 is located. The insulating part 53 has electrical insulation properties and prevents the relay conductive part 50 from contacting the outer container 3 of the battery 1. In one example, an electric wire is used for the relay conductive part 50, and the part covered by the electric wire becomes the insulating part 53. In another example, a substrate of a flexible printed wiring board is used as the insulating part 53, and a circuit formed on the substrate of the flexible printed wiring board becomes the relay conductive part 50. In another example, a conductor that becomes the relay conductive part 50 is formed integrally with the frame member 26 while being embedded inside the frame member 26. Then, a part of the frame member 26 becomes the insulating part 53.

[0047] In one example of FIG. 4 etc., a connection position 51 with the relay conductive part 50 is formed on the surface of the conductive layer 46 on the side where the battery group 21 is located. A frame bottom 35 is disposed between the connection position 51 and the battery group 21, and the frame bottom 35 prevents the conductive layer 46 and the relay conductive part 50 from contacting the outer container 3 of the battery 1. In one example of FIG. 4 , the connection position 51 of the relay conductive part 50 with the conductive layer 46 is formed between a certain insulating sheet 43 and one of the case side walls 33. At the connection position 51, the relay conductive part 50 is connected to the conductive layer 46 by, for example, soldering. In addition, when the metal body 27, the insulating layer 45 and the conductive layer 46 are formed from a metal base substrate and the relay conductive part 50 and the insulating part 53 are formed from a flexible printed wiring board, the relay conductive part 50 may be connected to the conductive layer 46 at the connection position 51 by a connector connection.

[0048] 4 and other examples, relay conductive part 50 is connected to one of bus bars 25 via a screw or the like at connection position 52. However, the connection of relay conductive part 50 to one of bus bars 25 is not limited to a configuration in which the connection is made by a screw, and may be a configuration in which the connection is made by soldering, a connector, or the like.

[0049] 4 and other examples, the case 22 includes extension portions 54, 55. The extension portion 54 extends outward from the case side walls 32, 33. The extension portion 55 is connected to the end of the extension portion 54 opposite the case side walls 32, 33, i.e., the end of the extension portion 54 protruding from the case side walls 32, 33, and extends from the extension portion 54 to the side opposite the side where the case top wall 31 is located. Therefore, the extension portions 54, 55 form portions protruding outward from the case side walls 32, 33.

[0050] The insulating layer 45 and the metal body 27 extend beyond the edge of the conductive layer 46 to the extension portion 55 in a direction intersecting the stacking direction of the insulating layer 45 and the conductive layer 46 (in the depth direction and lateral direction of the battery module 20 in this embodiment). In one example such as FIG. 4 , the edge of the insulating layer 45 and the outer edge of the metal body 27 abut against the extension portion 55. In addition, the edge of the conductive layer 46 is located on the inner side compared to the outer surfaces of the case side walls 32, 33. Therefore, by providing the extension portions 54, 55, a structure in which the insulating layer 45 and the metal body 27 extend to a region outside the edge of the conductive layer 46 in a direction intersecting the stacking direction can be easily realized.

[0051] As described above, in this embodiment, the insulating layer 45 is laminated on the surface of the metal body 27 on the side where the battery group 21 is located, and the conductive layer 46 is laminated on the surface of the insulating layer 45 on the side where the battery group 21 is located. The conductive layer 46 is electrically connected to one of the bus bars 25, and is electrically connected to an electrical path 47 through which a current flows during charging and discharging of the battery group 21. Therefore, the conductive layer 46 has the same potential as any position on the electrical path 47.

[0052] In addition, during charging and discharging of the battery group 21, the base on which the battery module 20 is installed is at ground potential. Therefore, when the battery module 20 is in use, a potential difference occurs between the electrical path 47 and the base. Furthermore, during charging and discharging of the battery group 21, the outer container 3 of each battery 1 may have a potential different from the ground potential due to conduction through an electrolyte or the like. Therefore, when the battery module 20 is in use, a potential difference occurs between the battery group 21 and the ground (base). In particular, when the battery module 20 is used as a power source for a railway, a plurality of battery modules including the battery module 20 are electrically connected in series as described above, and a large number of batteries are electrically connected in series. Therefore, depending on the battery module, the potential difference between the potential of the battery group 21 and the potential of the base (ground potential) becomes large.

[0053] As described above, a potential difference occurs between the battery group 21 and the ground (base), and thus a potential difference also occurs between the battery group 21 (electrical path 47) and the metal body 27. Here, in this embodiment, the conductive layer 46 has the same potential as any position of the electrical path 47. Therefore, when the battery module 20 is in use, a potential difference occurs between the electrical path 47 and the metal body 27, and therefore the conductive layer 46 has a different potential from the metal body 27.

[0054] In this embodiment, by providing the metal body 27 in the case 22, heat generated in the battery group 21 is easily dissipated from the metal body 27 to the outside of the battery module 20. This improves the heat dissipation performance of the battery module 20.

[0055] Furthermore, in this embodiment, since the conductive layer 46 is electrically connected to the electrical path 47, no voltage is applied between the conductive layer 46 and each of the electrical path 47 and the battery group 21. Therefore, no voltage is applied to the insulating sheet 43, the frame bottom 35, and the gaps (air layers) between each of the insulating sheets 43 and the frame bottom 35. Since no voltage is applied to the gaps between each of the insulating sheets 43 and the frame bottom 35, the occurrence of corona discharge in the gaps between each of the insulating sheets 43 and the frame bottom 35 is suppressed.

[0056] In addition, in this embodiment, the conductive layer 46 has a different potential from the metal body 27, so a voltage is applied to the insulating layer 45 between the conductive layer 46 and the metal body 27. However, there is no air, or very little air, between the metal body 27 and the insulating layer 45. There is also no air, or very little air, between the insulating layer 45 and the conductive layer 46. For this reason, even if a voltage is applied between the metal body 27 and the conductive layer 46, corona discharge is suppressed. Therefore, in this embodiment, even if the metal body 27 is provided to improve heat dissipation from the battery module 20, corona discharge in the air layer between the battery group 21 and the metal body 27 is effectively suppressed.

[0057] In addition, in this embodiment, since corona discharge is suppressed as described above, there is no need to fill the gaps between each of the insulating sheets 43 and the frame bottom 35 with an electrically insulating material or the like. In addition, the metal body 27, the insulating layer 45, and the conductive layer 46 can be easily formed integrally from a metal base substrate or the like. Therefore, corona discharge in the air layer between the battery group 21 and the metal body 27 is suppressed with a simple configuration. In other words, corona discharge is suppressed without increasing the effort required for manufacturing the battery module 20.

[0058] In this embodiment, the insulating layer 45 extends beyond the edge of the conductive layer 46 to an area outside the edge of the conductive layer 46 in a direction intersecting the lamination direction of the insulating layer 45 and the conductive layer 46. Therefore, the insulation distance (creepage distance) between the conductive layer 46 and the metal body 27 is increased by the dimension of the insulating layer 45 extending outward from the edge of the conductive layer 46. By increasing the insulation distance between the conductive layer 46 and the metal body 27, electrical insulation between the conductive layer 46 and the metal body 27 is appropriately ensured even if a potential difference occurs between the conductive layer 46 and the metal body 27.

[0059] Moreover, in this embodiment, the conductive layer 46 is electrically connected to one of the bus bars 25. Therefore, even if the exterior part of the battery (single cell) in the battery module is formed from a laminate film and the outer surface of the battery (single cell) has electrical insulation properties, it is possible to make the conductive layer 46 have the same potential as any position of the electrical path 47.

[0060] Moreover, in this embodiment, an insulating sheet (insulator) 43 is disposed between each of the battery rows 41 of the battery group 21 and the conductive layer 46. This effectively prevents the batteries 1 from being electrically connected through the conductive layer 46. Furthermore, in this embodiment, the insulating portion 53 prevents the relay conductive portion 50 from contacting the outer container 3 of the battery 1. This effectively prevents the batteries 1 from being electrically connected through the relay conductive portion 50. This effectively prevents the batteries 1 from being short-circuited through a portion other than the electrical path 47.

[0061] Furthermore, in this embodiment, each of the insulating sheets 43 has higher thermal conductivity than the air and the portions of the case 22 other than the metal body 27. Heat generated in the battery group 21 is transferred to the metal body 27 through the insulating sheets 43, the conductive layer 46, and the insulating layer 45. This improves the transfer of heat from the battery group 21 to the metal body 27, and further improves the heat dissipation performance of the battery module 20.

[0062] (Modification) 5, the relay conductive part 50 is also connected to the conductive layer 46 at a connection position 51. However, in this modification, the relay conductive part 50 is connected to one electrode terminal 11 of one of the batteries 1 in the battery pack 21 at a connection position 52. Therefore, in this modification, the conductive layer 46 is electrically connected to one of the pair of electrode terminals of a certain battery 1 via the relay conductive part 50. The relay conductive part 50 is connected to the certain electrode terminal 11 by soldering, screws, or the like.

[0063] In this modification, the conductive layer 46 is also electrically connected to an electrical path 47 through which a current flows during charging and discharging of the battery group 21. Therefore, the conductive layer 46 has the same potential as any position on the electrical path 47. Therefore, in this modification, as in the above-described embodiment, corona discharge in the air layer between the battery group 21 and the metal body 27 is effectively suppressed with a simple configuration.

[0064] In a modified example, the relay conductive part 50 may be connected at the connection position 52 to one of a pair of external terminals of the battery group 21, a detection circuit of the monitoring board 48, or the like. In this case, the conductive layer 46 is also electrically connected to the electrical path 47 and has the same potential as any position of the electrical path 47. Therefore, similar to the above-described embodiment, corona discharge in the air layer between the battery group 21 and the metal body 27 is effectively suppressed with a simple configuration.

[0065] 6, a relay conductive part 60 is provided instead of the relay conductive part 50. The relay conductive part 60 is connected to the conductive layer 46 at a connection position 61, and is connected to an outer container 3 of one of the batteries 1 in the battery group 21 at a connection position 62. Therefore, in this modification, the conductive layer 46 is electrically connected to the outer container 3 of one battery 1 via the relay conductive part 60. In this modification, one of the insulating sheets (insulators) 43 is formed with a hole 63 penetrating the insulating sheet 43 along the stacking direction of the insulating layer 45 and the conductive layer 46. The relay conductive part 60 is then disposed in the hole 63.

[0066] In this modification, the relay conductive part 60 is formed from a flexible conductive material, such as a spring such as a leaf spring, conductive rubber, or a conductive adhesive. By forming the relay conductive part 60 from a flexible material, manufacturing tolerances during manufacturing of the battery module 20 are absorbed. Therefore, the relay conductive part 60 is appropriately connected to the conductive layer 46 at the connection position 61, and is appropriately connected to the outer casing 3 of one battery 1 at the connection position 62.

[0067] In addition, when the relay conductive part 60 is formed of a spring and the metal body 27, the insulating layer 45, and the conductive layer 46 are formed of a metal base substrate, the relay conductive part 60 may be connected to the conductive layer 46 by soldering in order to improve the manufacturing efficiency of the battery module 20. In addition, when the outer container 3 of the battery 1 is formed of aluminum or an aluminum alloy and the relay conductive part 60 is formed of a spring, it is preferable that the connection position of the relay conductive part 60 to the outer container 3, i.e., the surface of the relay conductive part 60 that contacts the outer container 3, is nickel-plated. This effectively prevents oxidation of the surface at the connection position 62 of the relay conductive part 60. In addition, when the relay conductive part 60 is formed of conductive rubber and the metal body 27, the insulating layer 45, and the conductive layer 46 are formed of a metal base substrate, it is preferable that the surface of the conductive layer 46 is plated with a metal such as gold. This effectively prevents oxidation of the surface of the conductive layer 46.

[0068] In this modification, the conductive layer 46 is electrically connected to the exterior container 3 of one battery 1, i.e., a conductive portion of the battery group 21. Here, during charging and discharging of the multiple batteries 1, the potential of the exterior container 3 of the battery 1 to which the relay conductive portion 60 is connected becomes a potential between the potentials of the pair of electrode terminals 11 due to conduction via an electrolyte or the like. Therefore, the conductive layer 46 becomes a potential between the potentials of the pair of electrode terminals 11 of the battery 1 to which the relay conductive portion 60 is connected to the exterior container 3, and becomes the same potential as any position of the electrical path 47. Therefore, in this modification as well, as in the above-mentioned embodiment, corona discharge in the air layer between the battery group 21 and the metal body 27 is effectively suppressed with a simple configuration.

[0069] In the third modified example shown in FIG. 7, similarly to the modified example of FIG. 5, the conductive layer 46 is electrically connected to one electrode terminal 11 of one battery 1 via the relay conductive part 50, and is electrically connected to the electrical path 47. However, in this modified example, the surface of the conductive layer 46 on the side where the battery group 21 is located is covered with an insulating film (first insulating film) 71. The insulating film 71 is made of an electrically insulating material. The insulating film 71 is formed by applying a solder resist or a moisture-proof coating agent to the surface of the conductive layer 46 on the side where the battery group 21 is located. Also, the insulating film 71 is not formed on the connection part with the relay conductive part 50 in the conductive layer 46, but the insulating film 71 is formed on most of the surface of the conductive layer 46 on the side where the battery group 21 is located, except for the connection part with the relay conductive part 50.

[0070] In this modification, since the insulating coating 71 is provided, even if a crack or the like occurs in any of the insulating sheets 43, the multiple batteries 1 are effectively prevented from being electrically connected through the conductive layer 46. Therefore, the multiple batteries 1 are more effectively prevented from being short-circuited through a portion other than the electrical path 47.

[0071] In the fourth modification shown in FIG. 8, the outer surface of each of the outer containers 3 of the multiple batteries 1 is coated with an insulating coating (second insulating coating) 72. The insulating coating 72 is made of an electrically insulating material. The insulating coating 72 is formed by attaching an insulating material to the outer surface of the outer container 3. In this modification, the insulating coating 72 covers at least the entire outer surface of the bottom wall 7 of each of the outer containers 3 of the batteries 1. In this modification, since the insulating coating 72 is provided, even if a crack or the like occurs in any of the insulating sheets 43, the multiple batteries 1 are effectively prevented from being electrically connected through the conductive layer 46. Therefore, similar to the modification of FIG. 7, the multiple batteries 1 are even more effectively prevented from being short-circuited through a portion other than the electrical path 47.

[0072] In a configuration in which the conductive layer 46 is electrically connected to the exterior container 3 of a certain battery 1 as in the modified example of Fig. 6 and the insulating coating 72 is formed as in the modified example of Fig. 8, the insulating coating 72 is not formed at the connection portion between the exterior container 3 of a certain battery 1 and the relay conductive part 60. In a modified example, both the insulating coatings 71 and 72 may be formed.

[0073] In addition, in a fifth modified example shown in FIG. 9, a large number of holes 73 are formed in the conductive layer 46. FIG. 9 shows the conductive layer 46 viewed from one side in the stacking direction of the insulating layer 45 and the conductive layer 46. As shown in FIG. 9 and other figures, each of the holes 73 penetrates the conductive layer 46 in the stacking direction of the insulating layer 45 and the conductive layer 46. By forming a large number of holes 73, the conductive layer 46 becomes mesh-like when viewed from the stacking direction of the insulating layer 45 and the conductive layer 46. By forming the conductive layer 46 in a mesh-like shape, the contact area of ​​the conductive layer 46 with the insulating layer 45 becomes smaller, so that the electrostatic capacitance of the conductive layer 46 with respect to the metal body 27 is reduced. As a result, when the battery group 21 (electrical path 47) is used while being electrically connected to an inverter or the like, even if an AC voltage is applied between the conductive layer 46 and the metal body 27, leakage current is suppressed from flowing between the conductive layer 46 and the metal body 27.

[0074] In the example of FIG. 9, each of the many holes 73 has a circular shape when viewed from the stacking direction. In each of the holes 73, the circle forming the aforementioned circular shape is an inscribed circle of a regular hexagon. In each of the regular hexagons that form the circular shape of the corresponding hole 73 as an inscribed circle, the lattice points of the hexagonal lattice are located at six corners and the center. By forming the holes 73 as described above, it becomes possible to form many holes 73 in the conductive layer 46, and it becomes possible to reduce the contact area of ​​the conductive layer 46 with the insulating layer 45. In addition, since each of the holes 73 has a circular shape without corners when viewed from the stacking direction, electric field concentration in the area where the holes 73 are formed is reduced.

[0075] Moreover, from the viewpoint of appropriately suppressing corona discharge in the air layer between the battery group 21 and the metal body 27, it is preferable that the diameter of each of the circular holes 73 is as small as possible. When the metal body 27, the insulating layer 45, and the conductive layer 46 are formed from a metal base substrate, the conductive layer 46 can be formed in a mesh shape in the same manner as when the circuit portion of the printed wiring board is formed from a metal base substrate.

[0076] In the sixth modified example shown in FIG. 10, the metal body 27 of the case 22 forms a part of the case bottom wall and also forms a part of each of the pair of case side walls 33. Therefore, in this modified example, the metal body 27 is U-shaped or approximately U-shaped in a cross section perpendicular or approximately perpendicular to the lateral direction. In this modified example, the parts of the case 22 other than the metal body 27 have electrical insulation, and the metal body 27 has higher thermal conductivity than the parts of the case 22 other than the metal body 27. In this modified example, the insulating layer 45 is laminated on the surface of the metal body 27 on the side where the battery group 21 is located. And the conductive layer 46 is laminated on the surface of the insulating layer 45 on the side where the battery group 21 is located. In this modified example, each of the insulating layer 45 and the conductive layer 46 is also U-shaped or approximately U-shaped in a cross section perpendicular or approximately perpendicular to the lateral direction.

[0077] In this modification, the conductive layer 46 is electrically connected to one of a pair of electrode terminals 11 of one battery 1, and is electrically connected to an electrical path 47 through which a current flows during charging and discharging of the battery group 21. Therefore, the conductive layer 46 has the same potential as any position on the electrical path 47, and has a different potential from that of the metal body 27. Therefore, in this modification as well, as in the above-described embodiment, corona discharge in the air layer between the battery group 21 and the metal body 27 is effectively suppressed with a simple configuration.

[0078] Also in this modification, the insulating layer 45 extends beyond the edge of the conductive layer 46 to an area outside the edge of the conductive layer 46 in a direction intersecting the stacking direction of the insulating layer 45 and the conductive layer 46. Therefore, in this modification, as in the above-mentioned embodiment, the insulation distance (creepage distance) between the conductive layer 46 and the metal body 27 is large. Therefore, in this modification, electrical insulation between the conductive layer 46 and the metal body 27 is appropriately ensured.

[0079] In a modified example, the metal body 27 has a U-shape or a substantially U-shape in a cross section perpendicular or substantially perpendicular to the depth direction. In this case, the insulating layer 45 and the conductive layer 46 also have a U-shape or a substantially U-shape in a cross section perpendicular or substantially perpendicular to the depth direction. In this modified example, the insulating layer 45 is laminated on the surface of the metal body 27 on the side where the battery group 21 is located. The conductive layer 46 is laminated on the surface of the insulating layer 45 on the side where the battery group 21 is located. The insulating layer 45 extends beyond the edge of the conductive layer 46 to an area outside the edge of the conductive layer 46 in a direction intersecting the lamination direction of the insulating layer 45 and the conductive layer 46. Therefore, this modified example also has the same action and effect as the above-mentioned embodiment.

[0080] Furthermore, the number of batteries 1 forming the battery group 21 and the arrangement of the multiple batteries 1 in the battery group 21 are not limited to those in the above-described embodiment. The battery group 21 may include multiple batteries. Furthermore, the types of the multiple batteries 1 forming the battery group 21 are not particularly limited.

[0081] According to at least one of these embodiments or examples, the insulating layer is laminated on the surface of the metal body on the side where the battery group is located. The conductive layer is laminated on the surface of the insulating layer on the side where the battery group is located, and is electrically connected to either the electrical path or the conductive portion of the battery group. This makes it possible to provide a battery module in which corona discharge in the air layer between the battery group and the metal body is effectively suppressed with a simple configuration.

[0082] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. The following are additional notes. [1] A battery group including a plurality of batteries; an electrical path through which a current flows during charging and discharging of the plurality of batteries; a case for housing the battery group therein, the case including a conductive metal body; an insulating layer having electrical insulation properties and laminated on a surface of the metal body on which the battery group is located; a conductive layer that is laminated on a surface of the insulating layer on the side where the battery group is located, and is electrically connected to the electrical path and any of the conductive portions of the battery group; A battery module comprising: [2] The battery module of [1], wherein the insulating layer extends beyond the edge of the conductive layer to an area outside the edge of the conductive layer in a direction intersecting the stacking direction of the insulating layer and the conductive layer. [3] A bus bar that electrically connects the plurality of batteries and forms a part of the electrical path; a relay conductive portion connecting the conductive layer and the bus bar; The battery module of [1] or [2] further comprising: [4] Each of the plurality of batteries includes an electrode group and a metal outer container in which the electrode group is housed, the battery module further includes a relay conductive part that connects the exterior container of one of the plurality of batteries to the conductive layer. [1] or [2] Battery module. [5] The battery module according to any one of [1] to [4], further comprising an insulator having electrical insulation properties, disposed between the conductive layer and the battery group. [6] The battery module of [5], wherein the insulator has higher thermal conductivity than air and than parts of the case other than the metal body. [7] Each of the plurality of batteries includes an electrode group and a metal outer container in which the electrode group is housed; a hole is formed in the insulator so as to penetrate the insulator along a stacking direction of the insulating layer and the conductive layer; the battery module further includes a relay conductive part that is disposed in the hole of the insulator and connects the exterior container of one of the plurality of batteries to the conductive layer. [5] or [6] A battery module. [8] The battery module of any one of [1] to [7], further comprising a first insulating coating having electrical insulation properties and covering a surface of the conductive layer on which the battery group is located. [9] Each of the plurality of batteries includes an electrode group and a metal outer container in which the electrode group is housed; the battery module further includes a second insulating coating that is coated on an outer surface of the outer container in each of the plurality of batteries and has electrical insulation properties; [1] to [8] any one of the battery modules.

[10] The battery module according to any one of [1] to [9], wherein the conductive layer has a mesh-like shape when viewed from a stacking direction of the insulating layer and the conductive layer.

[11] Any one of the battery modules of [1] to

[10] , wherein the conductive layer is at the same potential as any one of the electrical paths and at a different potential from that of the metal body.

Claims

1. A battery group including a plurality of batteries; an electrical path through which a current flows during charging and discharging of the plurality of batteries; a case in which the battery group is housed, the case including a metal body having electrical conductivity, the metal body serving as a heat sink for radiating heat to the outside; an insulating layer having electrical insulation properties and laminated on a surface of the metal body on which the battery group is located; a conductive layer that is laminated on a surface of the insulating layer on the side where the battery group is located, and is electrically connected to either one of the electrical paths or a conductive portion of the battery group, and that is at the same potential as any one of the positions of the electrical paths and has a different potential from that of the metal body; an insulator having electrical insulation properties, the insulator being provided between the conductive layer and the battery group; A battery module comprising:

2. The battery module according to claim 1 , wherein the insulating layer extends beyond an edge of the conductive layer to an area outside the edge of the conductive layer in a direction intersecting a stacking direction of the insulating layer and the conductive layer.

3. A bus bar electrically connecting the plurality of batteries and forming a part of the electrical path; a relay conductive portion connecting the conductive layer and the bus bar; The battery module of claim 1 or 2, further comprising:

4. Each of the plurality of batteries includes an electrode group and a metal exterior container in which the electrode group is housed, the battery module further includes a relay conductive part that connects the exterior container of one of the plurality of batteries to the conductive layer. The battery module according to claim 1 or 2.

5. The battery module according to claim 1 , wherein the insulator has a higher thermal conductivity than air and a portion of the case other than the metal body.

6. Each of the plurality of batteries includes an electrode group and a metal exterior container in which the electrode group is housed, a hole is formed in the insulator so as to penetrate the insulator along a stacking direction of the insulating layer and the conductive layer; the battery module further includes a relay conductive portion disposed in the hole of the insulator and connecting the exterior container of one of the plurality of batteries to the conductive layer. The battery module according to claim 1 .

7. 7. The battery module according to claim 1, further comprising a first insulating coating having electrical insulation properties and covering a surface of said conductive layer on a side where said battery group is located.

8. Each of the plurality of batteries includes an electrode group and a metal exterior container in which the electrode group is housed, the battery module further includes a second insulating coating that is coated on an outer surface of the outer container in each of the plurality of batteries and has electrical insulation properties. The battery module according to any one of claims 1 to 7.

9. The battery module according to claim 1 , wherein the conductive layer has a mesh-like shape when viewed from a stacking direction of the insulating layer and the conductive layer.

Images