Battery module

Abstract

To provide a battery module having an excellent function of suppressing flame propagation between battery cells and an excellent function of dissipating heat from the battery cells.SOLUTION: A battery module 10 comprises: a plurality of battery cells 11; and a container containing the battery cells 11. The container includes: a housing 12 containing the battery cells 11; and a plate-shaped member 13 thermally connected to the housing 12 and partitioning a space in which the battery cells 11 of the housing 12 are accommodated into a plurality of spaces. The plate-shaped member 13 includes: a thermally conductive elastic body 13a; and a thermally conductive plate 13b disposed on one side or both sides of the thermally conductive elastic body 13a.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a battery module. [Background technology]

[0002] Secondary batteries that can be repeatedly used by charging are sometimes used in a state where multiple battery cells are housed in a container (hereinafter, also referred to as a battery module). If any one of the multiple battery cells included in a battery module explodes or catches fire, there is a risk that the other battery cells will explode or catch fire in a chain reaction, leading to a major accident. Therefore, Patent Document 1 proposes a battery module equipped with a function to prevent flame propagation between battery cells. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2020-524370 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery module described in Patent Document 1, the material of the member provided to prevent flame propagation is selected in consideration of heat insulation and heat resistance. For example, in the embodiment of Patent Document 1, mica with extremely low thermal conductivity is used. For this reason, the battery module described in Patent Document 1 may not have sufficient heat dissipation properties of the cells under normal conditions. An object of the present disclosure is to provide a battery module that is excellent in preventing flame propagation between battery cells and in dissipating heat from the battery cells. [Means for solving the problem]

[0005] Means for solving the above problems include the following embodiments. <1> A plurality of battery cells; a container that houses the battery cell; the container includes a housing that houses the battery cells, and a plate-like member that is thermally connected to the housing and divides a space of the housing in which the battery cells are housed into a plurality of spaces; The plate-shaped member includes a thermally conductive elastomer and a thermally conductive plate disposed on one or both sides of the thermally conductive elastomer. Battery module. <2> The plate-shaped member includes a thermally conductive elastic body and a thermally conductive plate disposed on both sides of the thermally conductive elastic body. <1> The battery module described in <3> At least a portion of a side wall surrounding a space of the housing that accommodates the battery cell includes a thermally conductive elastic material. <1> or <2> The battery module described in <4> The shape of the space in the housing that accommodates the battery cells is a rectangle surrounded by two pairs of opposing side walls, and at least one pair of the opposing side walls includes a thermally conductive elastic body. <1> ~ <3> 2. The battery module according to claim 1 . <5> The plate-like member has a flow path therein through which a coolant flows. <1> ~ <4> 2. The battery module according to claim 1 . Effect of the Invention

[0006] According to the present disclosure, a battery module is provided that is excellent in preventing flame propagation between battery cells and in dissipating heat from the battery cells. [Brief description of the drawings]

[0007] [Figure 1] FIG. 2 is a diagram illustrating an example of a configuration of a battery module. [Diagram 2] FIG. 1 is a diagram illustrating an example of application of a battery module to an electric vehicle. [Diagram 3] FIG. 2 is a diagram illustrating an example of a configuration of a battery module. [Figure 4] FIG. 2 is a diagram illustrating an example of a configuration of a battery module. [Diagram 5] 2 is a diagram illustrating an example of a configuration of a battery cell included in a battery module. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In the present disclosure, a numerical range indicated using "~" means a range that includes the numerical values ​​before and after "~" as the minimum and maximum values, respectively. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in the present disclosure. In the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a value shown in the examples.

[0009] The battery module of the present disclosure includes: A plurality of battery cells; a container that houses the battery cell; the container includes a housing that houses the battery cells, and a plate-like member that is thermally connected to the housing and divides a space of the housing in which the battery cells are housed into a plurality of spaces; The plate-like member includes a thermally conductive elastomer and a thermally conductive plate disposed on one or both sides of the thermally conductive elastomer.

[0010] The battery module of the present disclosure includes a plate-like member that divides the space in the housing in which the battery cells are housed into a plurality of spaces. Therefore, if an explosion or fire occurs in one of the battery cells, the plate-shaped member prevents the flames from spreading to the battery cells arranged in the space on the side where the exploded or ignited battery cell is not arranged. Furthermore, the plate-like members are thermally connected to the housing, so that heat generated in the battery cells is conducted to the housing via the plate-like members and dissipated to the outside of the battery module. In the present disclosure, "member A and member B are thermally connected" means that heat conduction between member A and member B is possible. Furthermore, the plate-shaped member includes a thermally conductive elastic body and a thermally conductive plate disposed on one or both sides of the thermally conductive elastic body. By including the thermally conductive elastic body in the plate-shaped member, the plate-shaped member is in an elastically deformable state. Therefore, the battery cells in the container can be kept in constant contact with the plate-shaped member, and heat generated in the battery cells is effectively dissipated via the plate-shaped member. In this disclosure, the term "elastic body" refers to a body that has the property of being deformed when a force is applied and returning to its original shape when the force is removed.

[0011] (Plate-shaped member) The plate-like member is thermally connected to a housing of a container that houses the battery cells, and divides the space of the housing that houses the battery cells into a plurality of spaces. From the standpoint of efficiently dissipating heat generated within the battery cells via the plate-like members, it is preferable that the plate-like members are always in close contact with the battery cells within the container. Battery cells have the property of expanding when charged and contracting when discharged, so if the plate-shaped member does not contain a thermally conductive elastic material, there is a risk of a gap being generated between the battery cell and the plate-shaped member when the battery cell is discharged. The plate-like member used in the present disclosure includes a thermally conductive elastic material, and is therefore capable of deforming in response to volumetric changes in the battery cell, and can maintain a state of close contact with the battery cell.

[0012] The state in which the plate-shaped member is in close contact with the battery cell can be created, for example, by putting the plate-shaped member in a state where it is pressed by the battery cell. The state in which the plate-shaped member is pressed by the battery cell can be created, for example, by designing the dimension D1 of the space for accommodating the battery cell partitioned by the plate-shaped member and the dimension D2 when the volume of the battery cell accommodated in the space is at its minimum, so that the relationship D1≦D2 is satisfied.

[0013] From the viewpoint of making the plate-like member elastically deformable, it is preferable that the heat conductive plate included in the plate-like member is capable of deforming or displacing in response to deformation of the heat conductive elastic body. Here, "deformable in response to deformation of the thermally conductive elastomer" means that the thermally conductive plate itself is deformable. "displaceable in response to deformation of the thermally conductive elastomer" means that the thermally conductive plate itself does not deform but can move in response to deformation of the thermally conductive elastomer (for example, movement in the thickness direction of a plate-shaped member).

[0014] The plate-like member may have a laminated structure made up of a thermally conductive elastic body and thermally conductive plates disposed on both sides of the thermally conductive elastic body.

[0015] The materials of the thermally conductive elastomer and the thermally conductive plate included in the plate-shaped member are not particularly limited as long as they are materials with excellent thermal conductivity. From the viewpoint of achieving sufficient heat dissipation, the thermal conductivity of the materials of the thermally conductive elastomer and the thermally conductive plate is preferably 10 W / (m·K) or more, more preferably 50 W / (m·K) or more, and even more preferably 100 W / (m·K) or more. Examples of materials with excellent thermal conductivity include metal, carbon, silicon, etc. Among these, metal is preferred from the viewpoint of strength and processability.

[0016] Specific examples of metals include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys containing the above metals. Among these metals, copper, aluminum, and alloys thereof are preferred from the viewpoints of thermal conductivity and economy. Aluminum and aluminum alloys are preferred from the viewpoint of weight reduction.

[0017] Specific examples of the thermally conductive elastic body contained in the plate-like member include a metal sponge and an aggregate of metal fibers. A specific example of the heat conductive plate included in the plate-like member is a metal plate.

[0018] From the viewpoint of heat dissipation efficiency, the area ratio of the main surface of the thermally conductive elastic body to the area of ​​the main surface of the plate-shaped member is preferably 50% or more, more preferably 70% or more, and even more preferably 90% or more. The area ratio of the thermally conductive elastic body to the area of ​​the main surface of the plate-shaped member may be 100%. When the above ratio is less than 100%, the thermally conductive elastic body may be provided in a pattern such as a stripe pattern or a dot pattern.

[0019] The plate-like member may have a flow path therein for circulating the coolant. When the thermally conductive elastic body has a porous structure, the voids in the porous structure may be used as the flow path for the coolant. The coolant may be either a liquid or a gas.

[0020] (Housing) There are no particular limitations on the housing that constitutes the container of the battery module, so long as it is capable of housing a plurality of battery cells. From the viewpoint of achieving sufficient heat dissipation, the thermal conductivity of the housing material is preferably 10 W / (m K) or more, more preferably 50 W / (m K) or more, and even more preferably 100 W / (m K) or more. Materials with excellent thermal conductivity include metal, carbon, silicon, etc. Among these, metal is preferred from the viewpoint of strength and processability.

[0021] Specific examples of metals include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys containing the above metals. Among these metals, copper, aluminum, and alloys thereof are preferred from the viewpoints of thermal conductivity and economy. Aluminum and aluminum alloys are preferred from the viewpoint of weight reduction.

[0022] The space in the housing that houses the battery cells is divided into a plurality of spaces by plate-shaped members. The plate-like member may or may not be removable from the housing. The space in the housing in which the battery cells are housed may be separated only by the plate-shaped member described above, or may be separated by the plate-shaped member and a member other than the plate-shaped member (for example, an inner wall portion integrally molded with the housing).

[0023] The housing may be in a state where at least a portion of a side wall surrounding a space that houses the battery cells includes a thermally conductive elastic material. For example, when the shape of the space in the housing that houses the battery cells is a rectangle surrounded by two pairs of opposing side walls, at least one pair of the opposing side walls may include a thermally conductive elastic body. Examples of the side wall containing a thermally conductive elastomer include a case where the thermally conductive elastomer is contained inside the side wall, and a case where the thermally conductive elastomer is arranged so as to be in contact with the inner wall surface of the side wall (the surface facing the space that houses the battery). The sidewall including the thermally conductive elastomer may include a thermally conductive plate together with the thermally conductive elastomer.

[0024] The number of battery cells arranged in each space partitioned by a plate-like member (or a plate-like member and another member) inside the housing may be one or more.

[0025] An example of the configuration of a container in which battery cells are housed will be described below with reference to the drawings. However, the embodiments of the present disclosure are not limited to the configurations shown in the drawings. In addition, the sizes of the components and the relative relationships between the components shown in the drawings are conceptual, and the embodiments of the present disclosure are not limited to these.

[0026] The battery module 10 shown in FIG. 1 is composed of a plurality of battery cells 11, a housing 12 that is a container for accommodating the battery cells 11, and a plate-shaped member 13 that divides the space in the housing 12 in which the battery cells 11 are accommodated into a plurality of spaces. The plate-like member 13 is composed of a thermally conductive elastic body 13a and thermally conductive plates 13b arranged on both sides of the thermally conductive elastic body 13a.

[0027] If an explosion or fire occurs in one of the battery cells 11 in the battery module 10 shown in FIG. 1, the plate-shaped member 13 prevents the flame from spreading to the battery cells 11 arranged in the space where the battery cell 11 is not arranged. Furthermore, heat generated within the battery cells 11 is conducted from the plate-like members 13 to the housing 12 and dissipated to the outside of the battery module 10 . The plate-like member 13 includes a thermally conductive elastic body 13a and is capable of elastic deformation, so that the plate-like member 13 is always maintained in close contact with the adjacent battery cells 11.

[0028] (Battery cell) There are no particular limitations on the battery cells included in the battery module of the present disclosure, so long as they can be housed in a container. From the viewpoint of heat dissipation efficiency, the shape of the battery cell is preferably one that ensures a sufficient contact area with the plate-shaped member. An example of such a battery cell is a battery in which the periphery of the electrode body is covered with a metal laminate film (so-called laminate cell).

[0029] The type of battery cells included in the battery module of the present disclosure is not particularly limited. The battery cells can be selected from secondary batteries such as lithium-ion secondary batteries (including liquid batteries and solid-state batteries), lead-acid batteries, nickel-metal hydride batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, and cobalt titanium lithium secondary batteries. From the standpoint of energy density, versatility, and the like, the battery cell may be a lithium ion secondary battery.

[0030] A lithium ion secondary battery includes, for example, a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode as necessary, and an electrolyte.

[0031] The positive electrode includes, for example, a current collector and a positive electrode layer disposed on the current collector. The positive electrode layer includes a positive electrode material. The positive electrode active material may be a composite oxide of lithium and a transition metal (hereinafter, also referred to as a lithium transition metal composite oxide). Examples of the transition metal include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, W, etc. Examples of the lithium transition metal composite oxide include layered lithium transition metal composite oxides, spinel type lithium transition metal composite oxides, and olivine type lithium transition metal composite oxides. The layered lithium transition metal composite oxide includes those containing at least one transition metal selected from Ni, Co, and Mn. Specifically, LiNi a Co b Mn c Examples of such compounds include compounds represented by the structural formula O2 (where a, b, and c are each a number between 0 and 1, and a+b+c=1), and compounds in which one or more elements selected from Al, Mg, La, Ti, Zn, B, W, Fe, Cr, V, Ru, Cu, Cd, Ag, Y, Sc, Ga, In, As, Sb, Pt, Au, Si, etc. are added to the above compounds. A specific example of the spinel-type lithium transition metal composite oxide is LiMn2O4. A specific example of the olivine-type lithium transition metal composite oxide is LiMPO4 (M: Fe, Co, Ni, or Mn). The positive electrode active material contained in the positive electrode material may be one type alone or two or more types. The positive electrode layer may contain components such as a conductive assistant and a binder in addition to the positive electrode active material. Examples of materials constituting the current collector of the positive electrode include aluminum, aluminum alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector include foil, mesh, etc.

[0032] The negative electrode includes, for example, a current collector and a negative electrode layer that is disposed on the current collector and contains a negative electrode active material. Examples of the negative electrode active material include carbon materials such as graphite, hard carbon, soft carbon, and activated carbon, silicon, metallic lithium, lithium alloys, and lithium titanate (LTO). The negative electrode layer may contain components such as a conductive assistant and a binder in addition to the negative electrode active material. Examples of the material constituting the negative electrode current collector include copper, copper alloy, nickel, titanium, stainless steel, etc. Examples of the shape of the negative electrode current collector include foil, mesh, etc.

[0033] Examples of the separator include nonwoven fabrics, cloths, microporous films, etc., whose main component is a polyolefin such as polyethylene or polypropylene. When the lithium ion secondary battery uses a solid electrolyte, it is not necessary to use a separator.

[0034] The electrolyte may be either liquid or solid. As the liquid electrolyte (electrolytic solution), a lithium salt such as LiPF6 dissolved in an organic solvent may be used without any particular limitation. As the solid electrolyte, a known solid electrolyte such as a sulfide solid electrolyte, an oxide solid electrolyte, or a halide solid electrolyte may be used without any particular limitation. The solid electrolyte may be a polymer containing a lithium salt.

[0035] The battery module of the present disclosure may be mounted on an electric vehicle. Hereinafter, an example in which the battery module of the present disclosure is applied to an electric vehicle will be described with reference to the drawings. In the following description, "battery pack 10" refers to a structure including multiple battery modules.

[0036] Fig. 2 is a schematic plan view showing a main part of a vehicle 100 to which a battery pack 10 according to an embodiment is applied. As shown in Fig. 2, the vehicle 100 is an electric vehicle (BEV: Battery Electric Vehicle) in which the battery pack 10 is mounted under the floor. Note that the arrows UP, FR, and LH in each figure indicate the upper side in the vehicle vertical direction, the front side in the vehicle longitudinal direction, and the left side in the vehicle width direction, respectively. When describing using the front-rear, left-right, up-down directions, they refer to the front-rear in the vehicle longitudinal direction, the left-right in the vehicle width direction, and the up-down in the vehicle vertical direction, unless otherwise specified.

[0037] As an example, in the vehicle 100 of this embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are disposed on the vehicle front side of the battery pack 10. In addition, a motor 108, a gear box 110, an inverter 112, and a charger 114 are disposed on the vehicle rear side of the battery pack 10.

[0038] The direct current output from the battery pack 10 has its voltage adjusted by a DC / DC converter 102, and is then supplied to an electric compressor 104, a PTC heater 106, an inverter 112, etc. In addition, power is supplied to a motor 108 via the inverter 112, causing the rear wheels to rotate and causing the vehicle 100 to run.

[0039] A charging port 116 is provided on the right side at the rear of the vehicle 100, and by connecting a charging plug of an external charging device (not shown) to the charging port 116, power can be stored in the battery pack 10 via the on-board charger 114.

[0040] The arrangement and structure of each component constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, the present invention may be applied to a hybrid vehicle (HV: Hybrid Vehicle) equipped with an engine or a plug-in hybrid vehicle (PHEV: Plug-in Hybrid Electric Vehicle). In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle in which the motor 108 is mounted at the rear of the vehicle, but the present invention is not limited to this. The vehicle may be a front-wheel drive vehicle in which the motor 108 is mounted at the front of the vehicle, or a pair of motors 108 may be mounted at the front and rear of the vehicle. Furthermore, the vehicle may be equipped with an in-wheel motor on each wheel.

[0041] The battery pack 10 includes a plurality of battery modules 11. In the present embodiment, as an example, ten battery modules 11 are provided. Specifically, five battery modules 11 are arranged on the right side of the vehicle 100 in the vehicle longitudinal direction, and five battery modules 11 are arranged on the left side of the vehicle 100 in the vehicle longitudinal direction. In addition, the respective battery modules 11 are electrically connected to each other.

[0042] Fig. 3 is a schematic perspective view of the battery module 11. As shown in Fig. 3, the battery module 11 is formed in a substantially rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is formed of an aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die castings to both ends of an aluminum alloy extrusion material by laser welding or the like.

[0043] A pair of voltage terminals 12 and a connector 14 are provided at both ends of the battery module 11 in the vehicle width direction. A flexible printed circuit board 21, which will be described later, is connected to the connector 14. In addition, bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0044] The length MW of the battery module 11 in the vehicle width direction is, for example, 350 mm to 600 mm, the length ML in the vehicle front-rear direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle up-down direction is, for example, 80 mm to 110 mm.

[0045] Fig. 4 is a plan view of the battery module 11 with the top cover removed. As shown in Fig. 4, a plurality of battery cells 20 are housed in an arranged state inside the battery module 11. In this embodiment, as an example, 24 battery cells 20 are arranged in the front-rear direction of the vehicle and bonded to one another.

[0046] A flexible printed circuit (FPC) 21 is disposed on the battery cells 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and a thermistor 23 is provided on each of both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cells 20, and is configured to be pressed towards the battery cells 20 by the upper lid of the battery module 11.

[0047] The space in which the battery cells 20 of the battery module 11 are housed is divided into a plurality of spaces by one or more plate-shaped members (not shown).

[0048] Fig. 5 is a schematic diagram of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Fig. 5, the battery cell 20 is formed in a substantially rectangular plate shape, and houses an electrode body (not shown) inside. The electrode body is configured by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22.

[0049] In this embodiment, as an example, the housing portion for the electrode body is formed by folding and pasting an embossed sheet-like laminate film 22. Note that, although both a single cup embossed structure in which embossing is performed at one place and a double cup embossed structure in which embossing is performed at two places can be adopted, the present embodiment adopts a single cup embossed structure with a drawing depth of about 8 mm to 10 mm.

[0050] The upper ends of the battery cells 20 at both ends in the longitudinal direction are bent to form corners. The upper end of the battery cells 20 is also bent, and a fixing tape 24 is wound around the upper end of the battery cells 20 along the longitudinal direction.

[0051] Here, terminals (tabs) 26 are provided at both longitudinal ends of the battery cell 20. In this embodiment, as an example, the terminals 26 are provided at positions offset downward from the vertical center of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0052] The length CW1 of the battery cell 20 in the vehicle width direction is, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, the length CW2 of the region in which the electrode body is housed is, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 to 900 mm, 1000 mm or more, and the height CH of the battery cell 20 is, for example, 80 mm to 110 mm, 110 mm to 140 mm. The thickness of the battery cell 20 is 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, 9.0 mm to 11.0 mm, and the height TH of the terminal 26 is 40 mm to 50 mm, 50 mm to 60 mm, 60 mm to 70 mm. [Explanation of symbols]

[0053] 10: Battery module 11: Battery cell 12: Housing 13: Plate-shaped member 13a: Thermally conductive elastomer 13b: Heat conductive plate

Claims

1. A plurality of battery cells; a container that houses the battery cell; the container includes a housing that houses the battery cells, and a plate-like member that is thermally connected to the housing and divides a space of the housing in which the battery cells are housed into a plurality of spaces; The plate-shaped member includes a thermally conductive elastomer and a thermally conductive plate disposed on one or both sides of the thermally conductive elastomer. Battery module.

2. The battery module according to claim 1 , wherein the plate-shaped member includes a thermally conductive elastic body and thermally conductive plates disposed on both sides of the thermally conductive elastic body.

3. The battery module according to claim 1 or 2, wherein at least a portion of a side wall surrounding a space of the casing that houses the battery cells includes a thermally conductive elastic material.

4. 3. The battery module according to claim 1, wherein the shape of the space of the housing that accommodates the battery cells is a rectangle surrounded by two pairs of opposing side walls, and at least one pair of the opposing side walls includes a thermally conductive elastic body.

5. The battery module according to claim 1 or 2, wherein the plate-like member has therein a flow path through which a coolant flows.

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