Battery modules and battery systems

Abstract

According to an embodiment, a battery module includes a battery pack, a shell, a metal plate, an insulator, and an electrical connection path. The battery pack includes a plurality of batteries, each of which includes an electrode group and a metal outer packaging container for accommodating the electrode group. The metal plate is arranged between the battery pack and the base, and there is a gap between the metal plate and the base. The insulating member has plasticity and electrical insulation and is sandwiched between the battery pack and the metal plate. The outer packaging containers of each of the plurality of batteries are electrically insulated from the metal plate by the insulating member. The electrical connection path electrically connects the metal plate to the base.

Description

Technical Field

[0001] Embodiments of the present invention relate to a battery module and a battery system. Background Art

[0002] In a battery module, a battery pack including a plurality of batteries (single cells) is accommodated in a storage space of a shell. In addition, as a battery module, from the viewpoint of improving the transferability of heat generated in the battery pack to the outside, there is a battery module in which a metal plate is provided and the heat is dissipated from the metal plate. In such a battery module, a component having plasticity is brought into close contact with each of the battery pack and the metal plate. Furthermore, heat is transferred from the battery pack to the metal plate through the component having plasticity, thereby improving the heat transferability from the battery pack to the metal plate. In addition, in such a battery module, an insulating member having electrical insulation is used as the above-mentioned component having plasticity. When the batteries of the battery pack are charged and discharged, the battery pack and the metal plate are electrically insulated by an insulating member or the like.

[0003] As described above, in a battery module including a metal plate and a battery system including the battery module, it is required to effectively prevent the metal plate from being charged and to effectively prevent discharge from the metal plate.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-60595

[0007] Patent Document 2: Japanese Patent Application Publication No. 2016-29624 Summary of the invention

[0008] Technical Problems to be Solved by the Invention

[0009] The technical problem to be solved by the present invention is to provide a battery module and a battery system which can effectively prevent the metal plate from being charged and the discharge from the metal plate in a structure provided with a metal plate for dissipating heat transferred from a battery pack to the outside.

[0010] Means for solving technical problems

[0011] According to an embodiment, a battery module disposed on a metal base is provided. The battery module includes a battery pack, a shell, a metal plate, an insulator, and an electrical connection path. The battery pack includes a plurality of batteries, and the plurality of batteries respectively include an electrode group and a metal outer packaging container for accommodating the electrode group. The shell includes a shell peripheral wall surrounding the storage space of the battery pack, and has electrical insulation. The metal plate is disposed between the battery pack and the base, and a gap is provided between the metal plate and the base. The insulating member has plasticity and electrical insulation, and is sandwiched between the battery pack and the metal plate. The outer packaging containers of each of the plurality of batteries are electrically insulated from the metal plate by the insulating member. The electrical connection path electrically connects the metal plate to the base.

[0012] According to an embodiment, a battery system includes the above-mentioned battery module and a metal base. The battery module is installed on the base with a metal plate located between the battery pack and the base. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a perspective view schematically showing an example of a battery cell used in the battery module according to the embodiment.

[0014] Figure 2 It is a perspective view showing a battery module provided in the battery system according to the first embodiment.

[0015] Figure 3 The state in which part of the shell is omitted is shown Figure 2 A three-dimensional view of a battery module.

[0016] Figure 4 Yes means Figure 2 A perspective view of a portion of a housing of a battery module.

[0017] Figure 5 Yes Figure 2 A three-dimensional diagram showing the battery module exploded into each component.

[0018] Figure 6 It is a cross-sectional view schematically showing the battery system according to the first embodiment.

[0019] Figure 7 This is a schematic diagram showing an example of the circuit configuration of the battery system according to the first embodiment.

[0020] Figure 8 This is a cross-sectional view schematically showing an electrical connection path and its vicinity in the battery system of the first embodiment.

[0021] Fig. 9 This is a cross-sectional view schematically showing an electrical connection path and its vicinity in a battery system according to a certain modification. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments will be described with reference to the drawings.

[0023] The battery system of the embodiment includes a base and a battery module installed on the base. In addition, a battery pack including a plurality of batteries (single cells) is mounted in the battery module. The batteries constituting the battery pack are secondary batteries such as lithium ion secondary batteries, for example.

[0024] [Battery]

[0025] First, the battery (single cell) will be described. Figure 1 An example of a battery 1 single body is shown. The battery 1 includes an electrode group 2 and an outer container 3 for storing the electrode group 2. The outer container 3 is formed 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, in the battery 1 and the outer container 3, a longitudinal direction (the direction indicated by arrows X1 and X2), a transverse direction (the direction indicated by arrows Y1 and Y2) intersecting the longitudinal direction (vertical or approximately perpendicular) and a height direction (the direction indicated by arrows Z1 and Z2) intersecting both the longitudinal direction and the transverse direction (vertical or approximately perpendicular) are defined. In each of the battery 1 and the outer container 3, the longitudinal dimension is very small compared to the transverse dimension and the height dimension, respectively.

[0026] The container body 5 includes a bottom wall 7 and a peripheral wall 8. An internal cavity 10 for accommodating the electrode group 2 is defined by the bottom wall 7 and the peripheral wall 8. In the battery 1, the internal cavity 10 is open toward the side opposite to the side where the bottom wall 7 is located in the height direction. The peripheral wall 8 includes two pairs of side walls 11 and 12. The pair of side walls 11 are opposed to each other with the internal cavity 10 sandwiched therebetween in the lateral direction. The pair of side walls 12 are opposed to each other with the internal cavity 10 sandwiched therebetween in the longitudinal direction. Each side wall 11 is continuously extended in the longitudinal direction between the side walls 12. Each side wall 12 is continuously extended in the lateral direction between the side walls 11. The cover 6 is mounted on the container body 5 at the opening of the internal cavity 10. Therefore, the cover 6 is mounted on the peripheral wall 8 at the end on the opposite side to the bottom wall 7. The cover 6 and the bottom wall 7 are opposed to each other with the internal cavity 10 sandwiched therebetween in the height direction.

[0027] The electrode group 2 is formed in a flat shape, for example, and includes a positive electrode 15 and a negative electrode 16. In the electrode group 2, a separator (not shown) is interposed between the positive electrode 15 and the negative electrode 16. The separator is formed of a material having electrical insulation properties, and electrically insulates the positive electrode 15 from the negative electrode 16.

[0028] The positive electrode 15 includes a positive electrode collector 15A such as a positive electrode collector foil and a positive electrode active material containing layer (not shown) carried on the surface of the positive electrode collector 15A. The positive electrode collector 15A is not limited to these, and is, for example, aluminum foil or aluminum alloy foil, etc., with a thickness of about 10μm to 20μm. The positive electrode active material containing layer includes a positive electrode active material and may arbitrarily contain a binder and a conductive agent. The positive electrode active material is not limited to this, and oxides, sulfides and polymers that can embed and deintercalate lithium ions can be cited. The positive electrode collector 15A includes a positive electrode collector ear 15B as a portion that does not carry the positive electrode active material containing layer.

[0029] The negative electrode 16 comprises a negative electrode collector 16A such as a negative electrode collector foil and a negative electrode active material containing layer (not shown) carried on the surface of the negative electrode collector 16A. The negative electrode collector 16A is not limited to these, and may be, for example, aluminum foil, aluminum alloy foil or copper foil, etc., with a thickness of about 10 μm to 20 μm. The negative electrode active material containing layer comprises a negative electrode active material, and may arbitrarily contain a binder and a conductive agent. The negative electrode active material is not particularly limited, and examples thereof include metal oxides, metal sulfides, metal nitrides and carbon materials that can embed and deintercalate lithium ions. The negative electrode collector 16A comprises a negative electrode collector ear 16B as a portion that does not carry the negative electrode active material containing layer.

[0030] In the electrode group 2, the positive electrode collector tab 15B protrudes relative to the negative electrode 16. Furthermore, the negative electrode collector tab 16B protrudes relative to the positive electrode 15 to the side opposite to the protruding direction of the positive electrode collector tab 15B. In the internal cavity 10 of the battery 1, the electrode group 2 is arranged in a state where the positive electrode collector tab 15B protrudes to one side in the lateral direction relative to the negative electrode 16. Furthermore, in the electrode group 2, the negative electrode collector tab 16B protrudes relative to the positive electrode 15 to the side opposite to the side where the positive electrode collector tab 15B protrudes in the lateral direction of the battery 1.

[0031] In addition, in the internal cavity 10, an electrolyte (not shown) is retained (impregnated) in the electrode group 2. The electrolyte may be a non-aqueous electrolyte in which an electrolyte is dissolved in an organic solvent, or an aqueous electrolyte such as an aqueous solution. Instead of the electrolyte, a gel electrolyte may be used, or a solid electrolyte may be used. When a solid electrolyte is used as the electrolyte, the solid electrolyte is sandwiched between the positive electrode 15 and the negative electrode 16 in the electrode group instead of the separator. In this case, the positive electrode 15 and the negative electrode 16 are electrically insulated by the solid electrolyte.

[0032] In the battery 1, a pair of electrode terminals 17 are installed on the outer surface (upper surface) of the cover 6 of the outer packaging container 3. The electrode terminal 17 is formed of a conductive material such as metal. One of the electrode terminals 17 is the positive terminal of the battery 1, and the other of the electrode terminals 17 is the negative terminal of the battery 1. An insulating member 18 is provided between each electrode terminal 17 and the cover 6. The electrode terminals 17 are electrically insulated from the outer packaging container 3 including the cover 6 by the insulating member 18.

[0033] The positive electrode collector tab 15B of the electrode group 2 is electrically connected to a corresponding one of the electrode terminals 17, i.e., the positive terminal, via one or more positive electrode leads such as the backup lead 21A and the lead 22A. In addition, the negative electrode collector tab 16B of the electrode group 2 is electrically connected to a corresponding one of the electrode terminals 17, i.e., the negative terminal, via one or more negative electrode leads such as the backup lead 21B and the lead 22B. The positive electrode lead and the negative electrode lead are respectively formed of a conductive material such as metal. In addition, in the internal cavity 10 of the outer packaging container 3, the positive electrode collector tab 15B and the positive electrode lead are respectively electrically insulated from the outer packaging container 3 (container body 5 and lid 6) by one or more insulating components (not shown). In addition, in the internal cavity 10 of the outer packaging container 3, the negative electrode collector tab 16B and the negative electrode lead are respectively electrically insulated from the outer packaging container 3 by one or more insulating components (not shown).

[0034] In addition, Figure 1 In one example, a gas release valve 23 and a liquid injection port are formed on the cover 6. In addition, a sealing plate 25 that blocks the liquid injection port is welded to the outer surface of the cover 6. In addition, the gas release valve 23 and the liquid injection port may not be provided on the battery. In addition, during the charging and discharging of the battery 1 as described above, due to the conduction through the electrolyte, etc., the outer packaging container 3 may become a potential between the potential of the positive terminal (the corresponding one in 17) (positive electrode potential) and the potential of the negative terminal (negative electrode potential).

[0035] [Battery modules and battery systems]

[0036] The battery module and the battery system including the battery module are described below. The battery system includes a battery module and a base on which the battery module is installed. The battery module includes a battery pack, and the battery pack includes a plurality of batteries (single cells). The plurality of batteries constituting the battery pack have, for example, the same structure as the battery 1 described above.

[0037] (First Embodiment)

[0038] Hereinafter, a first embodiment of the battery system will be described. Figure 2 and Figure 3 denoted by a battery module 31 provided in the battery system of this embodiment. Figure 2 and Figure 3As shown in the figures, the battery module 31 includes a battery pack 32 and a housing 33 for storing the battery pack 32. The housing space 35 of the battery pack 32 is defined by the housing 33. The battery pack 32 includes a plurality of the above-mentioned batteries (single cells) 1, and in the battery pack 32, the plurality of batteries 1 are electrically connected via a bus bar (not shown) or the like. In the battery pack 32, 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.

[0039] The housing 33 is formed of a material having electrical insulation properties. Examples of the material forming the housing 33 include resins such as polyphenylene ether, polycarbonate, and polybutylene terephthalate. Figure 2 and Figure 3 In one example, the housing 33 is formed by a plurality of parts including a housing part 36. Figure 3 , the portion of the housing 33 other than the housing member 36 is omitted. Here, in the battery module 31 including the battery pack 32 and the housing 33, a longitudinal direction (directions indicated by arrows X3 and X4), a lateral direction (directions indicated by arrows Y3 and Y4) intersecting (perpendicular or substantially perpendicular) the longitudinal direction, and a height direction (directions indicated by arrows Z3 and Z4) intersecting (perpendicular or substantially perpendicular) both the longitudinal direction and the lateral direction are defined.

[0040] Figure 4 denoted by a housing member 36 forming part of the housing 33. Figures 2 to 4 As shown, the shell 33 includes a shell top wall (shell upper wall) 41, a shell bottom wall 42 and a shell peripheral wall 43. In the shell 33, the shell top wall 41 and the shell bottom wall 42 are opposite to each other in the height direction across the storage space 35. The shell peripheral wall 43 extends continuously in the height direction between the shell top wall 41 and the shell bottom wall 42. In addition, the shell peripheral wall 43 surrounds the storage space 35 throughout the entire circumference of the battery module 31. The shell peripheral wall 43 includes two pairs of shell side walls 45 and 46. A pair of shell side walls 45 are opposite to each other in the transverse direction across the storage space 35. A pair of shell side walls 46 are opposite to each other in the longitudinal direction across the storage space 35. The shell side walls 45 are respectively extended continuously in the longitudinal direction between the shell side walls 46. The shell side walls 46 are respectively extended continuously in the transverse direction between the shell side walls 45.

[0041] In addition, the housing 33 has two partition walls 47. The partition walls 47 are disposed between the pair of housing side walls 45 in the lateral direction and are disposed to be separated from each other in the lateral direction. In addition, each partition wall 47 is disposed to be separated from each housing side wall 45 in the lateral direction. The partition walls 47 are respectively extended continuously in the height direction between the housing top wall 41 and the housing bottom wall 42. In addition, the partition walls 47 are respectively extended continuously in the longitudinal direction between the housing side walls 46. Since the two partition walls 47 are formed as described above, Figures 2 to 4In the example of FIG. 4 , the storage space 35 of the battery pack 32 is partitioned into three areas 48 by the partition wall 47 . That is, the storage space 35 is partitioned into three parts in the lateral direction by the partition wall 47 .

[0042] The bottom wall 42 of the housing supports the battery pack 32 from one side in the height direction. Three through holes 51 are formed in the bottom wall 42 of the housing. Each through hole 51 is formed in the bottom wall 42 of the housing at a position corresponding to one of the regions 48. The regions 48 of the storage space 35 are opened to the outside of the housing 33 through a corresponding one of the through holes 51. In each of the two regions located at both ends in the lateral direction among the three regions 48, the bottom wall 42 of the housing protrudes inwardly from the side walls 45, 46 of the housing and the partition wall 47, respectively, and the edges of the through holes 51 are formed by the protruding ends of the bottom wall 42 of the housing. In addition, in one region located in the middle in the lateral direction among the three regions 48, the bottom wall 42 of the housing protrudes inwardly from the side walls 46 of the housing and the partition wall 47, respectively, and the edges of the through holes 51 are formed by the protruding ends of the bottom wall 42 of the housing. Therefore, in each region 48 , the case bottom wall 42 is formed to protrude inwardly over the entire circumference, and in each through hole 51 , an edge is formed over the entire circumference by the protruding end of the case bottom wall 42 .

[0043] Figure 5 The battery module 31 is shown broken down into its components. Figure 5 In the figure, the parts of the housing 33 other than the housing member 36 are omitted for illustration. Figure 3 and Figure 5 As shown in FIG. 1 , in this embodiment, the battery pack 32 includes three battery rows 52. Each battery row 52 is arranged in a corresponding one of the regions 48 in the storage space 35. In addition, the battery rows 52 adjacent to each other in the lateral direction of the battery module 31 are separated by a partition wall 47. A plurality of batteries 1 are arranged in the battery pack 52. Figure 3 In one example, eight batteries 1 are arranged in each battery group 52. In each battery row 52, ​​the batteries 1 are arranged in a state where the arrangement direction of the batteries 1 is consistent or substantially consistent with the longitudinal direction of the battery module 31 (housing 33). In each of the three regions 48, the battery group 52 is supported by a protruding portion of the housing bottom wall 42 that protrudes toward the inner peripheral side.

[0044] In addition, in the battery pack 32 (each battery column 52), the longitudinal direction of each battery 1 is consistent or substantially consistent with the longitudinal direction of the battery module 31 (housing 33), and the lateral direction of each battery 1 is consistent or substantially consistent with the lateral direction of the battery module 31. Furthermore, in the battery pack 32, the height direction of each battery 1 is consistent or substantially consistent with the height direction of the battery module 31. Furthermore, the batteries 1 are arranged in the storage space 35 in a state where the outer surface of the bottom wall 7 faces the side where the bottom wall 42 of the housing is located, and the outer surface of the cover 6 faces the side where the top wall 41 of the housing is located. In addition, in each battery column 52, the plurality of batteries 1 are arranged without or substantially offset relative to each other in the lateral and height directions of the battery module 31. In addition, the three battery columns 52 are arranged without or substantially offset relative to each other in the longitudinal and height directions of the battery module 31.

[0045] In each battery column 52 of the battery pack 32, a partition plate (separator) 53 is provided between the batteries 1 adjacent to each other in the arrangement direction (the longitudinal direction of the battery module 31). Figure 3 In one example, seven partition plates 53 are provided on each battery column 52. At least the outer surface of each partition plate 53 is formed of a material having electrical insulation properties. As the material forming at least the outer surface of the partition plate 53, there can be cited electrical insulating resins such as polyphenylene ether (PPE), polycarbonate (PC) and polybutylene terephthalate (PBT). In addition, in each area 48, a partition plate 54 is formed by the shell 33. The area 48 is divided by the partition plate 54 into the same number of division ranges as the number of batteries 1 of a corresponding battery column forming the battery column 52. In each battery column 52, the battery 1 is respectively arranged in a corresponding one of the above-mentioned division ranges.

[0046] In addition, the battery module 31 includes a metal plate (bottom plate) 55 for setting the battery pack 32 and the housing 33. The thermal conductivity of the metal plate (heat sink) 55 is higher than that of the housing 33. As a material forming the metal plate 55, aluminum and aluminum alloys can be cited, for example. The metal plate 55 is attached to the housing 33 from the side where the housing bottom wall 42 is located in the height direction of the battery module 31. In addition, the metal plate 55 is formed into an appropriate size and shape as needed, and in one example, it is formed into a flat plate or a substantially flat plate with a thickness of about 0.5 mm or more and 5 mm or less.

[0047] Figure 6 The battery system 30 including the above-mentioned battery module 31 is schematically shown. Figure 5 and Figure 6As shown in the figures, the battery module 31 has three insulating sheets (insulators) 56. The insulating sheets 56 have plasticity and electrical insulation, and have higher thermal conductivity than the housing 33 and air. As a material for forming each insulating sheet 56, a resin having plasticity and electrical insulation, such as silicone, can be cited. However, each insulating sheet 56 has lower thermal conductivity than the metal plate 55. Each insulating sheet 56 is sandwiched between the battery pack 32 and the metal plate 55 in the height direction of the battery module 31.

[0048] Each insulating sheet 56 is arranged in a corresponding area of ​​the area 48 in the storage space 35. Each insulating sheet 56 is in close contact and abutment with a corresponding one of the battery groups 52 in a corresponding area of ​​the area 48. In each battery column 52, in the height direction of the battery module 31, from the side where the metal plate 55 is located, a corresponding one of the insulating sheets 56 is in close contact and abutment with each outer packaging container 3 (bottom wall 7) of the battery 1. In addition, in each battery column 52, in each battery 1, a part of the bottom wall 7 of the outer packaging container 3 abuts against the bottom wall 42 of the shell, or is bonded to the bottom wall 42 of the shell via an adhesive or the like. Thus, each battery column 52 is supported by the protruding portion of the bottom wall 42 of the shell that protrudes toward the inner peripheral side. In addition, in each battery 1 of the battery column 52, a corresponding one of the insulating sheets 56 is in close contact and abutment with the portion of the bottom wall 7 of the outer packaging container 3 other than the abutting portion and the bonding portion to the bottom wall 42 of the shell. In addition, each part of the insulating sheet 56 is arranged in a corresponding one of the through holes 51. And, a corresponding one of the insulating sheets 56 is inserted into each through hole 51, and each through hole 51 is substantially filled with the corresponding one of the insulating sheets 56. However, a small gap is formed between the insulating sheet 56 arranged in each through hole 51 and the protruding end of the housing bottom wall 42 due to manufacturing.

[0049] In addition, in the battery module 31, an insulating film 57 is formed on the surface of the metal plate 55 facing the side where the battery group 32 is located. Therefore, the insulating film 57 is formed between the insulating sheet 56 and the bottom wall 42 of the housing and the metal plate 55 in the height direction of the battery module 31. The insulating film 57 has electrical insulation. The insulating film 57 is formed of a resin having electrical insulation, such as a film of epoxy resin. The bottom wall 42 of the housing abuts against the insulating film 57 of the metal plate 55 from the side where the battery group 32 is located in the height direction. In addition, each insulating sheet 56 is in close contact with the insulating film 57 of the metal plate 55 from the side where the battery group 32 is located in the height direction of the battery module 31. Therefore, a corresponding one of the insulating sheets 56 is filled in the gap between each battery column 52 of the battery group 32 and the metal plate 55. The battery group 32 is electrically insulated from the metal plate 55 by the insulating sheet 56 and the insulating film 57. In addition, in each region 48, the bottom wall 42 of the housing protrudes toward the inner peripheral side relative to the insulating film 57.

[0050] Since the battery module 31 is formed as described above, the insulating sheet 56 and the bottom wall 42 of the housing are sandwiched between the battery group 32 and the metal plate 55 (including the insulating film 57) in the height direction of the battery module 31. In addition, in the battery module 31, the heat generated in each battery column 52 is transferred to the metal plate 55 through a corresponding one of the insulating sheets 56 and the insulating film 57. Each insulating sheet 56 transfers the heat transferred from the battery group 32 to the metal plate 55. Therefore, a heat transfer path from the battery group 32 to the metal plate 55 that does not pass through the air is formed by the insulating sheet 56 and the like.

[0051] like Figure 6 As shown in the figure, the battery system 30 has a metal base (cooling plate) 61 on which the battery module 31 is installed. Therefore, the battery pack 32, the shell 33 and the metal plate 55 are arranged on the base 61. The base 61 has a higher thermal conductivity than the shell 33 and the insulating sheet 56, for example, it has the same degree of thermal conductivity as the metal plate 55. In the battery system 30, the battery module 31 is used as a fixed power source or a power source for railway vehicles. Here, when the battery system 30 is used for example for railways, a plurality of batteries are connected in series, and high cooling performance is required. Therefore, in the battery system 30, the base 61 is set as a cooling plate in the portion contacted by the battery module 31, for example, a flow path for the flow of a cooling fluid containing a coolant or a cooling gas is set inside the base 61 serving as a cooling plate for forced cooling.

[0052] The base 61 is arranged on the side opposite to the side where the battery pack 32 is located with respect to the metal plate 55 in the height direction of the battery module 31. In addition, the base 61 is arranged to be separated from the metal plate 55 on the side opposite to the side where the battery pack 32 is located. That is, a gap is formed between the metal plate 55 and the base 61 in the height direction of the battery module 31. In one example, the gap between the metal plate 55 and the base 61 is about 0.2 mm.

[0053] In the battery system 30, an insulating layer 62 is formed in the gap between the metal plate 55 and the base 61. The insulating layer 62 has plasticity and electrical insulation. The insulating layer 62 is formed of a resin having plasticity and electrical insulation, such as silicone grease. The gap between the metal plate 55 and the base 61 is filled with the insulating layer 62. Therefore, the insulating layer 62 is sandwiched between the metal plate 55 and the base 61 in the height direction of the battery module 31. In addition, the insulating layer 62 is in close contact and abutment with the metal plate 55 and the base 61, respectively.

[0054] The insulating layer 62 is made of a material having a higher thermal conductivity than the air and the housing 33. However, the insulating layer 62 has a lower thermal conductivity than the metal plate 55 and the base 61. Since the battery system 30 is formed as described above, the heat generated in each battery column 52 is transferred to the base 61 through the corresponding one of the insulating sheets 56, the insulating film 57, the metal plate 55, and the insulating layer 62 in sequence. That is, the insulating layer 62 transfers the heat transferred from the metal plate 55 to the base 61. Therefore, a heat transfer path from the battery group 32 to the base 61 that does not pass through the air is formed by the insulating sheet 56, the metal plate 55, the insulating layer 62, etc.

[0055] Figure 7 FIG. 2 shows an example of a circuit configuration of the battery system 30. Figure 7 As shown in FIG. 1 , the battery pack 32 has a pair of external terminals 63A and 63B. The external terminal 63A is the positive external terminal of the battery pack 32 (battery module 31), and the external terminal 63B is the negative external terminal of the battery pack 32. In the battery system 30, the battery pack 32 is connected to the power source and the load (in Figure 7 The battery pack 32 (battery module 31) is electrically connected to the battery pack 32 (indicated by reference numeral 64 in the figure). The battery pack 32 (battery module 31) is charged by supplying power from the power source to the battery pack 32. In addition, the battery pack 32 (battery module 31) is discharged by supplying power from the battery pack 32 to the load.

[0056] exist Figure 7 In one example, the base 61 is grounded and the base 61 becomes GND. And, the GND side path of the current path of the current flowing through the battery pack 32 is connected to the base 61. In the battery pack 32, the external terminal (positive external terminal) 63A is connected to a load (for example, 64) without passing through a battery pack of other battery modules or the like, or through a battery pack of other battery modules or the like. In addition, in the battery pack 32, the external terminal (negative external terminal) 63B is connected to the ground side path (base 61) without passing through a battery pack of other battery modules or the like, or through a battery pack of other battery modules or the like. In addition, in a case where the external terminal 63B is connected to the ground side path without passing through a battery pack of other battery modules or the like, the potential (negative potential) of the external terminal 63B of the battery pack 32 is consistent with the potential of the base 61 and becomes the GND potential. For example, in a case where the battery system 30 is used in a railway vehicle, as Figure 7 As shown in the example, the base 61 is GND.

[0057] Here, in IEC62497-1, the insulation distance between two conductors is specified. The insulation distance of IEC62497-1 is specified by the creepage distance or the spatial distance between two conductors separated from each other. In addition, the allowable limit value of the insulation distance is set to the lower limit value of the range in which no discharge occurs between the two conductors when a voltage (potential difference) is generated between the two conductors. The allowable limit value of the insulation distance varies depending on the voltage between the two conductors. For example, in the provisions of IEC62497-1, when the creepage distance between the two conductors is 12 mm and the spatial distance is 6.7 mm, the rated pulse withstand voltage between the two conductors is 6 kV. That is, when the rated pulse voltage between the two conductors is 6 kV, the allowable limit value of the insulation distance is 12 mm in terms of the creepage distance and 6.7 mm in terms of the spatial distance.

[0058] In the battery system 30, during the charging and discharging of the battery pack 32, the outer packaging container 3 of each battery 1 sometimes becomes a potential different from GND (base 61) due to conduction through the electrolyte or the like. In this case, a potential difference (voltage) is generated between the base 61 and the battery pack 32 (the outer packaging container 3 of the battery 1), or a potential difference (voltage) is generated between the metal plate 55 and the battery pack 32 (the outer packaging container 3 of the battery 1). However, in this embodiment, an insulating sheet 56 and an insulating film 57 are arranged between the metal plate 55 and the battery pack 32. In addition, in each area 48, the shell bottom wall 42 protrudes from the shell peripheral wall 43 and the partition wall 47 to the inner peripheral side, and the shell bottom wall 42 protrudes to the inner peripheral side relative to the insulating film 57. As a result, the creepage distance between the metal plate 55 and the battery pack 32 is ensured to be a certain size. Therefore, the insulation distance (creepage distance) between the metal plate 55 and the battery pack 32 is greater than the above-mentioned allowable limit value. Furthermore, a certain creeping distance is also ensured between the base 61 and the battery pack 32 by the insulating layer 62 and the case 33. Therefore, the insulating distance (creeping distance) between the base 61 and the battery pack 32 is greater than the above-mentioned permissible limit value.

[0059] In addition, if Figure 2 As shown in the figures, in the battery module 31, the metal plate 55 is connected to the shell bottom wall 42 of the shell 33 by four connecting screws (first connecting parts) 71. And, in the battery system 30, the base 61 is connected to the shell bottom wall 42 of the shell 33 by four connecting screws (second connecting parts) 72. The connecting screws 72 are respectively located near a corresponding one of the connecting screws 71. In the present embodiment, the connecting screws 71 and 72 are respectively conductive, for example, formed of metal. In addition, the connecting screws 71 and 72 are respectively arranged on the outside of the storage space 35, and are arranged on the opposite side of the side where the storage space 35 is located relative to the shell peripheral wall 43.

[0060] In addition, in the battery system 30, an electrical connection path 65 is formed to electrically connect the metal plate 55 and the base 61 that are separated from each other. In the present embodiment, the connecting screw 71A, which is one of the connecting screws 71, forms a part of the electrical connection path 65. In the present embodiment, one of the connecting screws 72, namely the connecting screw 72A that exists near the connecting screw 71A, forms a part of the electrical connection path 65 that is different from the connecting screw 71A. In addition, the electrical connection path 65 is formed outside the storage space 35, and is formed on the side opposite to the side where the storage space 35 is located with respect to the housing peripheral wall 43.

[0061] Figure 8 65 and its vicinity. Figure 8 , the mounting structure of the connecting screw 71A to the metal plate 55 and the bottom wall 42 of the housing is shown, but the mounting structure of the connecting screws 71 other than the connecting screw 71A to the metal plate 55 and the bottom wall 42 of the housing is the same as that of the connecting screw 71A. Figure 8 , the mounting structure of the connecting screw 72A to the base 61 and the bottom wall 42 of the housing is shown, but the mounting structure of the connecting screws 72 other than the connecting screw 72A to the base 61 and the bottom wall 42 of the housing is also the same as that of the connecting screw 71A.

[0062] like Figure 2 and Figure 5 As shown in FIG. 1 and FIG. 2 , four protrusions 77 are provided on the metal plate 55 so as to protrude outwardly relative to the housing peripheral wall 43 of the housing 33. Figure 8 As shown in the figures, four holes 81 are formed on the bottom wall 42 of the shell along the height direction of the battery module 31. The holes 81 are arranged in the longitudinal and lateral directions of the battery module 31 without being offset from the corresponding one of the protrusions 77. Therefore, the holes 81 overlap with the corresponding one of the protrusions 77. The connecting screws 71 pass through the corresponding one of the protrusions 77 and are inserted into the corresponding one of the holes 81. In addition, a metal cylinder 75 is arranged in each hole 81. In each hole 81, the insertion portion of the connecting screw 71 is engaged with the metal cylinder 75 by, for example, screwing the external thread and the internal thread, so as to abut against the metal cylinder 75.

[0063] The head of a corresponding one of the connecting screws 71 contacts each of the protruding pieces 77 from the side where the base 61 is located in the height direction of the battery module 31. In addition, a recess 78 is formed on the surface of each of the protruding pieces 77 on the side facing the base 61. In each of the protruding pieces 77, the recess 78 is recessed toward the side where the battery pack 32 is located (the side opposite to the side where the base 61 is located) in the height direction of the battery module 31. In each of the protruding pieces 77, the head of a corresponding one of the connecting screws 71 is arranged in the recess 78. Therefore, each head of the connecting screw 71 does not protrude toward the side where the base 61 is located relative to the portion of the metal plate 55 other than the recess 78.

[0064] In addition, four through holes 83 are formed on the bottom wall 42 of the shell, which penetrate the bottom wall 42 of the shell in the height direction of the battery module 31. The through holes 83 are respectively formed in the vicinity of a corresponding one of the holes 81. Each connecting screw 72 is inserted through a corresponding one of the through holes 83. In addition, each connecting screw 72 penetrates the insulating layer 62 and is inserted into the inside of the base 61. In addition, each connecting screw 72 is engaged with the base 61 by, for example, screwing an external thread and an internal thread. In addition, each head of the connecting screw 72 is arranged on the side opposite to the side where the base 61 is located relative to the bottom wall 42 of the shell and the through holes 83.

[0065] In addition, in the present embodiment, in the electrical connection path 65, the connection screws 71A and 72A are electrically connected via the metal tube 75, the connection screws 73, and the relay plate 76. The relay plate 76 is mounted on the housing bottom wall 42 of the housing 33 via the connection screws 73. The relay plate 76 and the connection screws 73 are each conductive and are formed of, for example, metal. The relay plate 76 abuts against the housing bottom wall 42 from the side opposite to the side where the base 61 is located in the height direction of the battery module 31.

[0066] The relay plate 76 is sandwiched between the head of the connecting screw 72A and the bottom wall 42 of the shell, and is sandwiched between the head of the connecting screw 73 and the bottom wall 42 of the shell. In addition, the connecting screw 73 passes through the relay plate 76. And, the connecting screw 73 is inserted into a hole 81A in the hole 81 for inserting the connecting screw 71A. The hole 81A is a through hole that passes through the bottom wall 42 of the shell in the height direction of the battery module 31. And, in the hole 81A, the insertion portion of the connecting screw 73 is engaged with the metal cylinder 75, for example, by screwing the external thread and the internal thread, and abuts against the metal cylinder 75. In addition, the holes 81 other than the hole 81A do not pass through the bottom wall 42 of the shell.

[0067] Due to the above-mentioned structure, the metal plate 55 is electrically connected to the base 61 through the connecting screw 71A, the metal cylinder 75, the connecting screw 73, the relay plate 76, and the connecting screw 72 in sequence. That is, an electrical connection path 65 is formed from the metal plate 55 to the base 61 through the connecting screw 71A, the metal cylinder 75, the connecting screw 73, the relay plate 76, and the connecting screw 72 in sequence.

[0068] In this embodiment, the metal plate 55 and the base 61 are electrically connected via an electrical connection path 65. Figure 7 In one example, the metal plate 55 is electrically connected to the base 61, and the metal plate 55 is also grounded, and the metal plate 55 also becomes GND. By forming the electrical connection path 65, even if the metal plate 55 is provided on the battery module 31, it is possible to effectively prevent the metal plate 55 from being charged, and effectively prevent the potential difference (voltage) from being generated between the metal plate 55 and the base 61. As a result, discharge between the base 61 and the metal plate 55 can be effectively prevented. Therefore, in a structure in which the metal plate 55 is provided for dissipating heat transferred from the battery pack 32 to the outside, charging of the metal plate 55 and discharge from the metal plate 55 can be effectively prevented.

[0069] In addition, when the electrical connection path 65 is not provided, during the charging and discharging of the battery pack 32, each outer packaging container 3 of the battery 1 becomes a potential different from GND (base 61), thereby generating a potential difference (voltage) between each outer packaging container 3 of the battery 1 and the metal plate 55. As a result, the metal plate 55 is charged, and a potential difference (voltage) is generated between the base 61 and the metal plate 55. In addition, the insulating layer 62 between the base 61 and the metal plate 55 is thin, and the gap between the base 61 and the metal plate 55 is small. Therefore, when a potential difference is generated between the base 61 and the metal plate 55, when the base 61 and the metal plate 55 are observed from the surface passing through the inner surface of the housing 33, the insulation distance between the metal plate 55 and the base 61 may be less than the allowable limit value determined by IEC62497-1. In addition, due to the unevenness of the surfaces of the base 61 and the metal plate 55, and the inclusion of an air layer into the insulating layer 62 (voids), etc., which occur during manufacturing, the insulating layer 62 may be partially thinned. In this case, a voltage exceeding the withstand voltage for insulation breakdown is applied to a portion where the insulating layer 62 is locally thin, and discharge may occur from the metal plate 55 to the base 61. In this embodiment, no potential difference (voltage) is generated between the base 61 and the metal plate 55 through the electrical connection path 65. Therefore, even if the insulating layer 62 between the base 61 and the metal plate 55 is thin, discharge can be effectively prevented from occurring between the metal plate 55 and the base 61.

[0070] When the battery system 30 is used for railways, for example, a plurality of batteries are connected in series. At this time, the potential difference between the battery pack 32 and GND becomes large depending on the battery module. Here, although the insulation distance between the battery pack 32 and the metal plate 55 is sufficiently maintained, it is difficult to sufficiently ensure the insulation distance between the metal plate 55 and the base 61. Therefore, in this embodiment, a structure is realized in which no potential difference is generated between the metal plate 55 and the base 61 by providing an electrical connection path 65 between the metal plate 55 and the base 61.

[0071] In addition, an insulating sheet 56 and an insulating film 57 are arranged between the metal plate 55 and the battery pack 32. In addition, in each region 48, the housing bottom wall 42 protrudes from the housing peripheral wall 43 and the partition wall 47 to the inner peripheral side, and the housing bottom wall 42 protrudes to the inner peripheral side relative to the insulating film 57. As a result, when the battery pack 32 is charged and discharged, the insulation distance (creeping distance) between the metal plate 55 and the battery pack 32 becomes greater than the allowable limit value determined by IEC62497-1. Therefore, discharge between the metal plate 55 and the battery pack 32 can be effectively prevented. In addition, the base 61 and the battery pack 32 are electrically insulated by the insulating layer 62 and the housing 33. Moreover, when the battery pack 32 is charged and discharged, the insulation distance (creeping distance) between the base 61 and the battery pack 32 becomes greater than the allowable limit value determined by IEC62497-1. Therefore, discharge between the base 61 and the battery pack 32 can be effectively prevented.

[0072] In addition, in the present embodiment, a metal plate 55 is provided between the battery pack 32 and the base 61, and heat is dissipated from the metal plate 55 to the base 61. Since heat is dissipated from the battery module 31 through the metal plate 55 having high thermal conductivity, the thermal conductivity from the battery pack 32 to the base 61, that is, the heat dissipation from the battery module 31 to the base 61 is improved.

[0073] In addition, in the present embodiment, an insulating sheet 56 having plasticity is sandwiched between the battery pack 32 and the metal plate 55. Furthermore, the insulating sheet 56 is in close contact with the battery pack 32 and the metal plate 55 (insulating film 57), respectively. In addition, the thermal conductivity of the insulating sheet 56 is higher than the thermal conductivity of the air and the shell 33. Therefore, the thermal conductivity from the battery pack 32 to the metal plate 55 is improved. In addition, in the present embodiment, an insulating layer 62 having plasticity is sandwiched between the base 61 and the metal plate 55. Furthermore, the insulating layer 62 is in close contact with the base 61 and the metal plate 55. In addition, the thermal conductivity of the insulating layer 62 is higher than the thermal conductivity of the air and the shell 33. Therefore, the thermal conductivity from the metal plate 55 to the base 61 is improved.

[0074] In addition, in the present embodiment, the electrical connection path 65 is formed outside the storage space 35, and is formed on the side opposite to the side where the storage space 35 is located with respect to the housing peripheral wall 43. Therefore, the battery pack 32 in the storage space 35 is electrically insulated from the electrical connection path 65 by the housing peripheral wall 43. Therefore, during the charging and discharging of the battery pack 32, the insulation distance (creepage distance) between the battery pack 32 and the electrical connection path 65 can be appropriately ensured, and the discharge between the electrical connection path 65 and the battery pack 32 can also be effectively prevented.

[0075] In addition, in the present embodiment, one (71A) of the connecting screws 71 connecting the metal plate 55 to the housing 33 forms a part of the electrical connection path 65, and one (72A) of the connecting screws 72 connecting the base 61 to the housing 33 forms a part of the electrical connection path 65. Therefore, even if the electrical connection path 65 is formed, the number of additional components can be reduced. In addition, in the present embodiment, by engaging the connecting screws 72A with the base 61, the metal plate 55 is electrically connected to the base 61, and the metal plate 55 is grounded. Therefore, when the metal plate 55 is grounded, it is not necessary to use additional components other than the connecting screws 72 used when setting the battery module 31 to the base 61. Therefore, the operator can visually confirm whether the metal plate 55 is electrically connected to the base 61 from the opposite side (upper side) of the base 61. Therefore, it is not easy for the operator to forget the operation of electrically connecting the metal plate 55 to the base 61, that is, the operation of grounding the metal plate 55.

[0076] (Variation Example)

[0077] In addition, the structure of the electrical connection path 65 is not limited to the structure of the above-mentioned embodiment and the like. Fig. 9 In the modification shown, as in the above-mentioned embodiment, the connection screw 71A, which is one of the connection screws 71, forms a part of the electrical connection path 65, and the metal tube 75 and the connection screw 73 form a part of the electrical connection path 65. However, in this modification, the relay plate 76 is not provided, and the connection screw 72 provided near the connection screw 71A is not included in the electrical connection path 65. In this modification, an electrical wiring 85 such as a wire is provided. And one end of the electrical wiring 85 is connected to the connection screw 73, and the other end of the electrical wiring 85 is connected to the base 61. Thus, the connection screw 73 is electrically connected to the base 61 via the electrical wiring 85.

[0078] Due to the above-mentioned structure, the metal plate 55 is electrically connected to the base 61 through the connecting screw 71A, the metal cylinder 75, the connecting screw 73, and the electrical wiring 85 in sequence. That is, an electrical connection path 65 is formed from the metal plate 55 to the base 61 through the connecting screw 71A, the metal cylinder 75, the connecting screw 73, and the electrical wiring 85 in sequence. In this modification, since the electrical connection path 65 is also formed, the discharge between the base 61 and the metal plate 55 can be effectively prevented, and the discharge from the metal plate 55 can be effectively prevented, as in the above-mentioned embodiment.

[0079] In addition, in a certain modification, a nut may be provided instead of the connecting screw 73 and the metal cylinder 75. In this case, the connecting screw 71A passes through the hole 81A, and the nut engages with the connecting screw 71A, for example, by screwing an external thread and an internal thread. In addition, the nut abuts against the relay plate 76 from the side opposite to the side where the base 61 is located. In this modification, an electrical connection path 65 is formed from the metal plate 55 through the connecting screw 71A, the nut, the relay plate 76 and the connecting screw 72A to the base 61 in sequence. In this modification, since the electrical connection path 65 is also formed, as in the above-mentioned embodiment, the discharge between the base 61 and the metal plate 55 can be effectively prevented, and the discharge from the metal plate 55 can be effectively prevented.

[0080] In a certain modification, the base 61 is in contact with the metal plate 55 by the elastic force of a spring (not shown) or the like in a part of the gap between the base 61 and the metal plate 55. Thus, an electrical connection path (65) is formed in the contact portion between the base 61 and the metal plate 55 to electrically connect the metal plate 55 and the base 61. In this modification, since the electrical connection path 65 is also formed, the discharge between the base 61 and the metal plate 55 can be effectively prevented, and the discharge from the metal plate 55 can be effectively prevented, as in the above-mentioned embodiment.

[0081] In addition, in a certain variation, a sheet having plasticity and conductivity is arranged in the gap between the base 61 and the metal plate 55. And the sheet arranged in the gap is in contact with the metal plate 55 and the base 61. The sheet is, for example, a rubber sheet mixed with silver. In this variation, an electrical connection path 65 is formed from the metal plate 55 through the above-mentioned sheet to the base 61. In this variation, since the electrical connection path 65 is also formed, the discharge between the base 61 and the metal plate 55 can be effectively prevented, and the discharge from the metal plate 55 can be effectively prevented, as in the above-mentioned embodiment.

[0082] In the above-described embodiments and the like, one electrical connection path 65 is formed in the battery module 31 . However, a plurality of electrical connection paths having the same structure as any of the above-described structures may be provided in the battery module 31 .

[0083] In addition, the number of batteries 1 forming the battery pack 32 and the arrangement of the plurality of batteries 1 in the battery pack 32 are not limited to the above-described embodiment, etc. The battery pack 32 may include a plurality of batteries.

[0084] According to at least one of these embodiments or examples, the metal body is disposed between the battery pack and the metal base, with a gap between the metal body and the base. Furthermore, the insulator has plasticity and electrical insulation, and is sandwiched between the battery pack and the metal body. Furthermore, the metal plate is electrically connected to the base via an electrical connection path. Thus, in a structure provided with a metal plate for dissipating heat transferred from the battery pack to the outside, a battery module that effectively prevents charging of the metal plate and discharge from the metal plate can be provided.

[0085] Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the subject matter of the invention. These embodiments and their variations are included in the scope and subject matter of the invention, and are included in the invention described in the claims and the scope of their equivalents.

Claims

1. A battery module, arranged on a metal base, the battery module comprising: a battery pack, comprising a plurality of batteries, each of the plurality of batteries comprising an electrode group, and a metal outer packaging container for accommodating the electrode group; a shell, comprising a shell peripheral wall surrounding a storage space of the battery pack, and having electrical insulation; a metal plate, arranged between the battery pack and the base in such a manner that the plate surface is parallel to a surface of the base on which the battery module is arranged, and a gap is provided between the metal plate and the base; an insulator, having plasticity and electrical insulation, sandwiched between the battery pack and the metal plate, the insulator electrically insulating the outer packaging container of each of the plurality of batteries from the metal plate; an electrical connection path, electrically connecting the metal plate to the base; A first metal connecting member connects the housing and the metal plate to form a part of the electrical connection path; and a second metal connecting member connects the housing and the base to form a part of the electrical connection path different from the first connecting member.

2. The battery module according to claim 1, wherein: The insulator transfers heat transferred from the battery pack to the metal plate, and the thermal conductivity of the insulator is higher than that of air and the case.

3. The battery module according to claim 1 or 2, wherein: The electrical insulation distance between the metal plate and the battery pack is equal to or greater than an allowable limit value of the insulation distance determined by IEC62497-1.

4. The battery module according to any one of claims 1 or 2, wherein: The electrical connection path is formed outside the storage space of the battery pack and is formed on a side opposite to a side where the storage space is located with respect to the peripheral wall of the housing.

5. The battery module according to claim 1, wherein: It also includes: a metal relay board installed on the shell; and a metal third connecting component connecting the relay board and the shell; the relay board and the third connecting component electrically connect the first connecting component and the second connecting component in the electrical connection path.

6. The battery module according to claim 1 or 2, wherein: The shell has a shell bottom wall, which supports the battery pack from the side where the metal plate is located, and the metal plate is installed from the side opposite to the side where the battery pack is located. The shell bottom wall protrudes from the shell peripheral wall toward the inner peripheral side, and a through hole is formed in the shell bottom wall to open the storage space of the battery pack relative to the outside of the shell, and the protruding end of the shell bottom wall protruding from the shell peripheral wall forms at least a part of the edge of the through hole, and the insulator is arranged in the through hole. 7 . A battery system comprising: the battery module according to claim 1 ; and the metal base, wherein the battery module is installed in a state where the metal plate is located between the base and the battery pack.

8. The battery system according to claim 7, wherein: An insulating layer is further provided, which is formed in the gap between the metal plate and the base and has plasticity and electrical insulation.

9. The battery system according to claim 8, wherein: The insulating layer transfers the heat transferred from the metal plate to the base. The thermal conductivity of the insulating layer is higher than that of air and the housing.

10. The battery system according to any one of claims 7 to 9, wherein: The electrical insulation distance between the base and the battery pack is greater than or equal to the allowable limit of the insulation distance determined by IEC62497-1.

11. The battery system according to any one of claims 7 to 9, wherein: The base is GND, i.e. grounded.

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