Battery module

Abstract

The invention discloses a battery module. A battery module provided with a plurality of battery cells and a container for housing the battery cells, the container including a case for housing the battery cells and a plate-shaped member thermally connected to the case and dividing the space of the case for housing the battery cells into a plurality of spaces, the plate-like member includes a heat-conducting elastic body and a heat-conducting plate disposed on one side or both sides of the heat-conducting elastic body.

Description

Technical Field

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

[0002] A secondary battery that can be used repeatedly by being charged is sometimes used in a state where a plurality of battery cells are housed in a container (hereinafter also referred to as a battery module).

[0003] Japanese Patent Application No. 2020-524370 proposes a battery module having a function of preventing flame propagation between battery cells. Summary of the invention

[0004] The material of the components of the battery module described in Japanese Patent Table 2020-524370 for preventing the spread of flames is selected in consideration of thermal insulation and heat resistance. For example, mica with extremely low thermal conductivity is used in the embodiment of Japanese Patent Table 2020-524370. Therefore, the battery module described in Japanese Patent Table 2020-524370 has the risk of insufficient heat dissipation of the unit under normal circumstances.

[0005] An object of the present disclosure is to provide a battery module having an excellent flame propagation prevention function between battery cells and a heat dissipation function of the battery cells.

[0006] Means for solving the above-mentioned problems include the following embodiments.

[0007] (1) A battery module comprising a plurality of battery cells and a container for housing the battery cells.

[0008] The container includes a housing for accommodating the battery cells and a plate-shaped member that is thermally connected to the housing and divides a space of the housing for accommodating the battery cells into a plurality of spaces.

[0009] The plate-shaped member includes a heat-conductive elastic body and a heat-conductive plate disposed on one side or both sides of the heat-conductive elastic body.

[0010] (2) In the battery module according to (1), the plate-shaped member includes a thermally conductive elastic body and thermally conductive plates disposed on both sides of the thermally conductive elastic body.

[0011] (3) In the battery module according to (1) or (2), at least a portion of a side wall of the case surrounding a space for accommodating the battery cells includes a thermally conductive elastic body.

[0012] (4) In the battery module according to any one of (1) to (3), the battery cell storage space of the case has a rectangular shape surrounded by two pairs of opposing side walls, and at least one pair of the opposing side walls includes a thermally conductive elastic body.

[0013] (5) In the battery module according to any one of (1) to (4), the plate-shaped member has a flow path therein through which a coolant flows.

[0014] According to the present disclosure, it is possible to provide a battery module having an excellent flame propagation prevention function between battery cells and a heat dissipation function of the battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Features, advantages, and technical and industrial significance of typical embodiments of the present invention are described below with reference to the accompanying drawings, in which like reference numerals represent like components, and in which:

[0016] Figure 1 A diagram schematically showing an example of the configuration of a battery module;

[0017] Figure 2 A diagram schematically showing an example of application of a battery module in a pure electric vehicle (battery electric vehicle);

[0018] Figure 3 A diagram schematically showing an example of the configuration of a battery module;

[0019] Figure 4 A diagram schematically showing an example of the configuration of a battery module;

[0020] Figure 5 This is a diagram schematically showing an example of the configuration of battery cells included in a battery module. DETAILED DESCRIPTION

[0021] In the present disclosure, a numerical range designated by “A to B”, “between A and B”, “(from) A to B”, etc., means a range including a minimum A and a maximum B.

[0022] In the numerical ranges recorded in stages in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can be replaced by the upper limit or lower limit in other numerical ranges recorded in stages. In the numerical ranges recorded in the present disclosure, the upper limit or lower limit recorded in a certain numerical range can also be replaced by the value shown in the embodiments.

[0023] The battery module disclosed herein comprises:

[0024] a plurality of battery cells; and

[0025] a container for accommodating the battery cell,

[0026] The container includes a housing for accommodating the battery cells and a plate-shaped member that is thermally connected to the housing and divides a space of the housing for accommodating the battery cells into a plurality of spaces.

[0027] The plate-shaped member includes a heat-conductive elastic body and a heat-conductive plate disposed on one side or both sides of the heat-conductive elastic body.

[0028] The battery module of the present disclosure includes a plate-shaped member that divides a space of a case for accommodating battery cells into a plurality of spaces.

[0029] Therefore, when an explosion or fire occurs in one of the battery cells, the plate-shaped member can prevent the flame from spreading to the battery cells arranged in the space on the side where the battery cell is not arranged.

[0030] Furthermore, the plate-shaped member is thermally connected to the housing, so that heat generated in the battery cells is conducted to the housing via the plate-shaped member and is dissipated to the outside of the battery module.

[0031] In the present disclosure, “member A and member B are thermally connected” means a state in which heat conduction is possible between member A and member B.

[0032] Furthermore, the plate-like member includes a heat-conductive elastic body and a heat-conductive plate disposed on one side or both sides of the heat-conductive elastic body. Since the plate-like member includes the heat-conductive elastic body, the plate-like member is in an elastically deformable state. Therefore, the battery cells in the container can always be in close contact with the plate-like member, and the heat generated in the battery cells can be effectively dissipated through the plate-like member.

[0033] In the present disclosure, the term “elastic body” refers to an object having the property of deforming when a force is applied and returning to its original shape when the force is removed.

[0034] Plate-like components

[0035] The plate-shaped member is thermally connected to the case of the container for accommodating the battery cells, and divides the space of the case for accommodating the battery cells into a plurality of spaces.

[0036] From the viewpoint of efficiently dissipating the heat generated in the battery cell via the plate-shaped member, the plate-shaped member is preferably always in close contact with the battery cell in the container.

[0037] The battery cell has the property of expanding during charging and contracting during discharging. Therefore, if the plate-shaped member does not include a heat-conductive elastic body, a gap may be generated between the battery cell and the plate-shaped member during discharging of the battery cell.

[0038] Since the plate-shaped member used in the present disclosure includes a heat-conductive elastic body, it can deform in accordance with the volume change of the battery cell and can maintain a state of close contact with the battery cell.

[0039] The state in which the plate-shaped member and the battery cell are in close contact can be created, for example, by placing the plate-shaped member in a state in which the battery cell is compressed. The state in which the plate-shaped member is compressed by the battery cell can be created, for example, by designing so that the relationship D1≤D2 is satisfied. D1 is the size of the space divided by the plate-shaped member for accommodating the battery cell. D2 is the size when the volume of the battery cell accommodated in the space becomes the smallest.

[0040] From the viewpoint of making the plate-like member elastically deformable, it is preferred that the heat-conductive plate included in the plate-like member be deformable or displaceable in accordance with the deformation of the heat-conductive elastic body.

[0041] Here, “capable of deformation according to the deformation of the heat-conductive elastic body” means that the heat-conductive plate itself is deformable. “capable of displacement according to the deformation of the heat-conductive elastic body” means that the heat-conductive plate itself is not deformed, but can move according to the deformation of the heat-conductive elastic body (for example, movement in the thickness direction of the plate-like member).

[0042] The plate-like member may have a stacked structure composed of a thermally conductive elastic body and thermally conductive plates disposed on both sides of the thermally conductive elastic body.

[0043] The material of the heat-conductive elastomer and the heat-conductive plate contained in the plate-like member is not particularly limited as long as it is a material with excellent thermal conductivity. From the viewpoint of achieving sufficient heat dissipation, the thermal conductivity of the material of the heat-conductive elastomer and the heat-conductive plate is preferably 10 W / (m·K) or more, more preferably 50 W / (m·K) or more, and further preferably 100 W / (m·K) or more. Examples of materials with excellent thermal conductivity include metals, carbon, and silicon. Among them, metals are preferred from the viewpoints of strength and processability.

[0044] Specific examples of the metal include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys thereof. Among these metals, copper, aluminum, and alloys thereof are preferred from the viewpoint of thermal conductivity and economic efficiency. From the viewpoint of weight reduction, aluminum and aluminum alloys are preferred.

[0045] Specific examples of the heat-conductive elastic body contained in the plate-like member include metal sponges, aggregates of metal fibers, and the like.

[0046] As the heat conductive plate included in the plate-like member, specifically, a metal plate may be mentioned.

[0047] From the viewpoint of heat dissipation efficiency, the ratio of the area of ​​the main surface of the heat-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 ratio of the area of ​​the main surface of the plate-shaped member to the area of ​​the heat-conductive elastic body may be 100%.

[0048] When the above ratio is less than 100%, the thermally conductive elastic body may be provided in a pattern such as a stripe or dot.

[0049] The plate-like member may have a flow path for circulating the refrigerant inside. When the heat-conductive elastic body has a porous structure, the voids in the porous structure may be used as the flow path for the refrigerant. The refrigerant may be either liquid or gas.

[0050] case

[0051] The case constituting the container of the battery module is not particularly limited as long as it can accommodate a plurality of battery cells.

[0052] From the perspective of achieving sufficient heat dissipation, the thermal conductivity of the material of the housing is preferably 10 W / (m·K) or more, more preferably 50 W / (m·K) or more, and further preferably 100 W / (m·K) or more. Materials with excellent thermal conductivity include metals, carbon, silicon, etc. Among them, metals are preferred from the perspective of strength and processability.

[0053] Specific examples of the metal include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys thereof. Among these metals, copper, aluminum, and alloys thereof are preferred from the viewpoint of thermal conductivity and economic efficiency. From the viewpoint of weight reduction, aluminum and aluminum alloys are preferred.

[0054] The space of the case for accommodating the battery cells is divided into a plurality of spaces by the plate-like member.

[0055] The plate-like member may be detachable from the housing or may be non-detachable from the housing.

[0056] The space of the case for accommodating the battery cells may be partitioned only by the plate-like member described above, or may be partitioned by the plate-like member and a member independent of the plate-like member (for example, an inner wall portion integrally formed with the case).

[0057] The case may be in a state where at least a portion of a side wall surrounding a space for accommodating the battery cell includes a thermally conductive elastic body.

[0058] For example, when the shape of the space for accommodating the battery cells in the case is a square surrounded by two pairs of opposing side walls, at least one pair of the opposing side walls may include a thermally conductive elastic body.

[0059] Examples of the state in which the side wall includes the thermally conductive elastic body include a case in which the thermally conductive elastic body is included inside the side wall and a case in which the thermally conductive elastic body is arranged in contact with the inner wall surface (surface on the battery storage space side) of the side wall.

[0060] The side wall including the thermally conductive elastic body may include the thermally conductive elastic body and the thermally conductive plate.

[0061] The number of battery cells disposed in each of the spaces partitioned by the plate-shaped member (or the plate-shaped member and other members) inside the housing may be one or more.

[0062] Hereinafter, an example of the structure of a container for storing a battery cell will be described with reference to the accompanying drawings. However, the embodiments of the present disclosure are not limited to the structures described in the following drawings. In addition, the relative relationship between the sizes of the components and the sizes between the components shown in the drawings are conceptual, and the embodiments of the present disclosure are not limited by them.

[0063] Figure 1 The battery module 10 shown in FIG. 1 is composed of a plurality of battery cells 11 , a case 12 that is a container for accommodating the battery cells 11 , and a plate-like member 13 that divides the space of the case 12 for accommodating the battery cells 11 into a plurality of spaces.

[0064] The plate-shaped member 13 is composed of a heat-conductive elastic body 13 a and heat-conductive plates 13 b arranged on both sides of the heat-conductive elastic body 13 a .

[0065] exist Figure 1 In the battery module 10 shown, when an explosion or fire occurs in one of the battery cells 11 , the plate-shaped member 13 can prevent the flame from spreading to the battery cells 11 arranged in the space where the battery cell 11 is not arranged.

[0066] Furthermore, heat generated in the battery cells 11 is conducted from the plate-shaped member 13 to the case 12 , and is dissipated to the outside of the battery module 10 .

[0067] Since the plate-shaped member 13 includes the heat-conductive elastic body 13 a and is elastically deformable, it is possible to always maintain a state of close contact with the adjacent battery cells 11 .

[0068] Battery Cell

[0069] The battery cells included in the battery module of the present disclosure are not particularly limited as long as they can be accommodated in a container.

[0070] From the viewpoint of heat dissipation efficiency, the shape of the battery cell is preferably a shape that can sufficiently ensure the contact area with the plate-shaped member. Such a battery cell may be a battery in which the periphery of the electrode body is covered with a metal laminate film (so-called laminate cell).

[0071] The type of battery cells included in the battery module of the present disclosure is not particularly limited.

[0072] The battery cell can be selected from secondary batteries such as lithium ion secondary batteries, lead batteries, nickel-hydrogen batteries, nickel-cadmium batteries, nickel-iron batteries, nickel-zinc batteries, silver oxide-zinc batteries, and cobalt-titanium lithium secondary batteries. Lithium ion secondary batteries include liquid batteries and all-solid batteries.

[0073] From the viewpoints of energy density, versatility, etc., the battery cell may be a lithium-ion secondary battery.

[0074] 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.

[0075] The positive electrode includes, for example, a current collector and a positive electrode layer disposed on the current collector. The positive electrode layer contains a positive electrode active material.

[0076] As the positive electrode active material, composite oxides of lithium and transition metals (hereinafter also referred to as lithium transition metal composite oxides) can be listed. As the transition metal, Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, W, etc. can be listed.

[0077] Examples of the lithium transition metal composite oxide include layered lithium transition metal composite oxides, spinel lithium transition metal composite oxides, and olivine lithium transition metal composite oxides.

[0078] Examples of layered lithium transition metal composite oxides include lithium transition metal composite oxides containing at least one selected from Ni, Co and Mn as a transition metal. Specifically, examples of layered lithium transition metal composite oxides include lithium transition metal composite oxides having a structural formula of LiNi a Co b Mn cO2 (a, b, c are numbers greater than or equal to 0 and less than or equal to 1, respectively, and a + b + c = 1). In addition, as layered lithium transition metal composite oxides, compounds obtained by adding 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. to the above compounds can be cited.

[0079] Specific examples of spinel-type lithium transition metal composite oxides include LiMn 2 O 4 .

[0080] Specific examples of the olivine-type lithium transition metal composite oxide include LiMPO 4 (M: Fe, Co, Ni or Mn).

[0081] The positive electrode active material contained in the positive electrode material may be a single type or two or more types.

[0082] The positive electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the positive electrode active material.

[0083] Examples of the material of the current collector constituting the positive electrode include aluminum, aluminum alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector include foil, mesh, and the like.

[0084] The negative electrode includes, for example, a current collector and a negative electrode layer disposed on the current collector and containing a negative electrode active material.

[0085] 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).

[0086] The negative electrode layer may contain components such as a conductive auxiliary agent and a binder in addition to the negative electrode active material.

[0087] Examples of the material of the current collector constituting the negative electrode include copper, copper alloys, nickel, titanium, stainless steel, etc. Examples of the shape of the current collector of the negative electrode include foil, mesh, and the like.

[0088] Examples of the separator include nonwoven fabrics, woven fabrics, and microporous films mainly composed of polyolefins such as polyethylene and polypropylene. When a solid electrolyte is used in a lithium ion secondary battery, a separator may not be used.

[0089] Regarding the electrolyte, it can be either liquid or solid. As a liquid electrolyte (electrolyte), a liquid electrolyte obtained by dissolving a lithium salt such as LiPF6 in an organic solvent can be used without particular restrictions. As a solid electrolyte, a known solid electrolyte such as a sulfide solid electrolyte, an oxide solid electrolyte, a halide solid electrolyte, etc. can be used without particular restrictions. The solid electrolyte can also be a solid electrolyte obtained by containing a lithium salt in a polymer.

[0090] The battery module of the present disclosure can be installed in a pure electric vehicle. Hereinafter, an example of applying the battery module of the present disclosure to a pure electric vehicle will be described with reference to the accompanying drawings.

[0091] In the following description, the “battery pack 10 ” means a structure including a plurality of battery modules.

[0092] Figure 2 1 is a schematic plan view showing the main parts of a vehicle 100 to which the battery pack 10 according to the embodiment is applied. Figure 2 As shown, the vehicle 100 is a pure electric vehicle (BEV) equipped with a battery pack 10 under the floor. In addition, the arrows UP, FR, and LH in each figure respectively represent the upper side in the vehicle vertical direction, the front side in the vehicle front-back direction, and the left side in the vehicle width direction. When the front-back, left-right, up-down and left-right directions are used for explanation, unless otherwise specified, they represent the front-back direction in the vehicle front-back direction, the left-right direction in the vehicle width direction, and the up-down direction in the vehicle vertical direction.

[0093] As an example of a vehicle 100 of the present embodiment, a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 are arranged on the vehicle front side relative to the battery pack 10. In addition, an electric motor 108, a gearbox 110, an inverter 112, and a charger 114 are arranged on the vehicle rear side relative to the battery pack 10.

[0094] The DC current output from battery pack 10 is regulated in voltage by DC / DC converter 102 and then supplied to electric compressor 104, PTC heater 106, inverter 112, etc. Furthermore, by supplying power to electric motor 108 via inverter 112, the rear wheels rotate and vehicle 100 travels.

[0095] A charging port 116 is provided on the right side of the rear portion of the vehicle 100 . By connecting a charging plug of an external charging device (not shown) to the charging port 116 , electricity can be stored in the battery pack 10 via the on-vehicle charger 114 .

[0096] The configuration and structure of the various components constituting the vehicle 100 are not limited to the above-mentioned configuration. For example, it can also be applied to a hybrid vehicle (HV: Hybrid Vehicle) or a plug-in hybrid electric vehicle (PHEV: Plug-in Hybrid Electric Vehicle) equipped with an engine. In addition, in the present embodiment, the vehicle is a rear-wheel drive vehicle with the motor 108 mounted at the rear of the vehicle, but it is not limited to this. It can also be a front-wheel drive vehicle with the motor 108 mounted at the front of the vehicle, or a pair of motors 108 can be mounted at the front and rear of the vehicle. In addition, it can also be a vehicle equipped with a hub motor on each wheel.

[0097] The battery pack 10 is composed of a plurality of battery modules 11. In the present embodiment, as an example, 10 battery modules 11 are provided. Specifically, on the right side of the vehicle 100, five battery modules 11 are arranged in the front-rear direction of the vehicle, and on the left side of the vehicle 100, five battery modules 11 are arranged in the front-rear direction of the vehicle. In addition, each battery module 11 is electrically connected.

[0098] Figure 3 FIG. 1 is a schematic three-dimensional diagram of the battery module 11. Figure 3 As shown, the battery module 11 is formed into a substantially rectangular parallelepiped shape with the vehicle width direction as the length direction. In addition, 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-cast bodies at both ends of an aluminum alloy extrusion material by laser welding or the like.

[0099] 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 described later is connected to the connector 14. Bus bars (not shown) are welded to both ends of the battery module 11 in the vehicle width direction.

[0100] The battery module 11 has a length MW in the vehicle width direction of, for example, 350 mm to 600 mm, a length ML in the vehicle front-rear direction of, for example, 150 mm to 250 mm, and a height MH in the vehicle up-down direction of, for example, 80 mm to 110 mm.

[0101] Figure 4 FIG. 1 is a plan view of the battery module 11 with the upper cover removed. Figure 4 As shown, a plurality of battery cells 20 are accommodated in an aligned state inside the battery module 11. In the present embodiment, as an example, 24 battery cells 20 are aligned in the vehicle front-rear direction and are joined to each other.

[0102] A flexible printed circuit (FPC) 21 is disposed on the battery cell 20. The flexible printed circuit 21 is formed in a strip shape with the vehicle width direction as the longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit 21. The thermistor 23 is not bonded to the battery cell 20 and is pressed toward the battery cell 20 by the upper cover of the battery module 11.

[0103] The space for accommodating the battery cells 20 in the battery module 11 is partitioned into a plurality of spaces by one or more plate-like members (not shown).

[0104] Figure 5 2 is a schematic diagram of a battery cell 20 housed in a battery module 11 as viewed from the thickness direction. Figure 5 As described above, the battery cell 20 is formed in a substantially rectangular plate shape, and an electrode body (not shown) is housed therein. The electrode body is formed by laminating a positive electrode, a negative electrode, and a separator, and is sealed with a laminate film 22 .

[0105] In this embodiment, as an example, the storage portion of the electrode body is formed by folding and laminating the embossed sheet-shaped laminate film 22. Furthermore, two structures can be adopted, namely, a single cup embossing structure with embossing at one place and a double cup embossing structure with embossing at two places, but in this embodiment, a single cup embossing structure with a drawing depth of about 8 mm to 10 mm is adopted.

[0106] The upper ends of both ends of the battery cell 20 in the longitudinal direction are bent, and the corners become the outer shape. In addition, the upper end of the battery cell 20 is bent, and a fixing band 24 is wound around the upper end of the battery cell 20 in the longitudinal direction.

[0107] Here, terminals (tabs) 26 are provided at both ends in the longitudinal direction of the battery cell 20. In the present embodiment, as an example, the terminals 26 are provided at positions offset downward from the center in the vertical direction of the battery cell 20. The terminals 26 are joined to a bus bar (not shown) by laser welding or the like.

[0108] The length CW1 of the battery cell 20 in the vehicle width direction can be, for example, 530 mm to 600 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, or 1000 mm or more. The length CW2 of the area for storing the electrode body can be, for example, 500 mm to 520 mm, 600 mm to 700 mm, 700 mm to 800 mm, 800 mm to 900 mm, or 1000 mm or more. The height CH of the battery cell 20 can be, for example, 80 mm to 110 mm, 110 mm to 140 mm. In addition, the thickness of the battery cell 20 can be 5.0 mm to 7.0 mm, 7.0 mm to 9.0 mm, or 9.0 mm to 11.0 mm, and the height TH of the terminal 26 can be 40 mm to 50 mm, 50 mm to 60 mm, or 60 mm to 70 mm.

Claims

1. A battery module comprising a plurality of battery cells and a container for accommodating the battery cells, The container includes a housing for accommodating the battery cells and a plate-shaped member that is thermally connected to the housing and divides a space of the housing for accommodating the battery cells into a plurality of spaces. The plate-shaped member includes a heat-conductive elastic body and a heat-conductive plate disposed on one side or both sides of the heat-conductive elastic body. 2 . The battery module according to claim 1 , wherein the plate-shaped member includes a heat-conductive elastic body and heat-conductive plates disposed on both sides of the heat-conductive elastic body. 3 . The battery module according to claim 1 , wherein at least a portion of a side wall of the case surrounding a space for accommodating the battery cells includes a thermally conductive elastic body.

4. The battery module according to claim 1 or 2, wherein the space for accommodating the battery cells of the housing is in a square shape surrounded by two pairs of facing side walls, and at least one pair of the facing side walls includes a heat conductive elastic body. 5 . The battery module according to claim 1 , wherein the plate-shaped member has a flow path therein for circulating a refrigerant.

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