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 Art

[0002] A secondary battery that can be repeatedly used by charging may be used in a state where a plurality of battery cells are housed in a container (hereinafter also referred to as a battery module). If any one of the plurality of battery cells included in the battery module explodes or catches fire, there is a risk that other battery cells will also explode or catch fire in a chain, leading to a major accident. Therefore, Patent Document 1 proposes a battery module having a function of preventing flame propagation between battery cells.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery module described in Patent Document 1, the material of the member provided for preventing flame propagation is selected in consideration of heat insulation and heat resistance. For example, in the embodiment of Patent Document 1, mica having an extremely low thermal conductivity is used. Therefore, the battery module described in Patent Document 1 may not have sufficient heat dissipation of the cells during normal operation. An object of the present disclosure is to provide a battery module that is excellent in a function of preventing flame propagation between battery cells and a heat dissipation function of battery cells.

Means for Solving the Problems

[0005] Means for solving the above problems include the following embodiments. <1> A plurality of battery cells, a container for housing the battery cells, The container includes a housing for housing battery cells and a plate-shaped member that is thermally connected to the housing and divides the space in the housing where the battery cells are housed into a plurality of spaces. The plate-like member includes a heat-conducting elastic body and a heat-conducting plate disposed on one or both sides of the heat-conducting elastic body. Battery module. <2> The plate-like member includes a heat-conducting elastic body and heat-conducting plates arranged on both sides of the heat-conducting elastic body. <1> The battery module described above. <3> At least a portion of the side wall surrounding the space for housing the battery cells of the aforementioned housing includes a thermally conductive elastic material. <1> or <2> The battery module described above. <4> The shape of the space in the housing that houses the battery cells is a rectangle surrounded by two pairs of opposing side walls, and at least one pair of opposing side walls contains a heat-conducting elastic material. <1> ~ <3> A battery module as described in any one of the items. <5> The aforementioned plate-shaped member has a flow path inside through which the refrigerant flows. <1> ~ <4> A battery module as described in any one of the items. [Effects of the Invention]

[0006] According to this disclosure, a battery module is provided that excels in flame propagation prevention between battery cells and heat dissipation of battery cells. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram schematically shows an example of a battery module configuration. [Figure 2] This diagram schematically illustrates an example of the application of a battery module to an electric vehicle. [Figure 3] This diagram schematically shows an example of a battery module configuration. [Figure 4] This diagram schematically shows an example of a battery module configuration. [Figure 5] This diagram schematically shows an example of the configuration of a battery cell included in a battery module. [Modes for carrying out the invention]

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

[0009] The battery module disclosed herein is Multiple battery cells, The battery comprises a container for housing the aforementioned battery cell, The container includes a housing for housing battery cells and a plate-shaped member that is thermally connected to the housing and divides the space in the housing where the battery cells are housed into a plurality of spaces. The plate-like member includes a heat-conducting elastic body and a heat-conducting plate disposed on one or both sides of the heat-conducting elastic body.

[0010] The battery module of this disclosure includes a plate-shaped member that divides the space in the housing where the battery cells are housed into multiple spaces. Therefore, if an explosion or fire occurs in one of the battery cells, the plate-shaped member prevents the flame from spreading to the battery cells located in the space where the affected battery cell is not located. Furthermore, the plate-shaped member is thermally connected to the housing. Therefore, the heat generated within the battery cell is conducted to the housing via the plate-shaped member and dissipated to the outside of the battery module. In this disclosure, "member A and member B are thermally connected" means that heat conduction is possible between member A and member B. Furthermore, the plate-like member includes a thermally conductive elastic body and thermally conductive plates disposed on one or both sides of the thermally conductive elastic body. By including the thermally 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. In the present disclosure, the "elastic body" means an object having the property of deforming when a force is applied and returning to its original shape when the force is removed.

[0011] (Plate-like member) The plate-like member is thermally connected to the housing of the container that houses the battery cells and divides the space in the housing where the battery cells are housed into a plurality of spaces. From the viewpoint of efficiently dissipating the heat generated in the battery cells through the plate-like member, it is preferable that the plate-like member is always in close contact with the battery cells in the container. The battery cells have the property of expanding during charging and contracting during discharging. Therefore, when the plate-like member does not include a thermally conductive elastic body, there is a possibility that a gap may occur between the plate-like member and the battery cells during discharging. Since the plate-like member used in the present disclosure includes a thermally conductive elastic body, it can deform following the volume change of the battery cells and maintain a state of close contact with the battery cells.

[0012] The state where the plate-like member is in close contact with the battery cells can be created, for example, by making the plate-like member be in a state of being pressed by the battery cells. The state where the plate-like member is pressed by the battery cells can be created, for example, by designing such that the dimension D1 of the space for housing the battery cells partitioned by the plate-like member and the dimension D2 when the volume of the battery cells housed in the space is minimized satisfy the relationship D1 ≤ D2.

[0013] From the viewpoint of making the plate-like member in an elastically deformable state, it is preferable that the thermally conductive plates included in the plate-like member are deformable or displaceable in accordance with the deformation of the thermally conductive elastic body. Here, "deformable in accordance with the deformation of the heat-conducting elastic material" means that the heat-conducting plate itself is deformable. "Displaceable in accordance with the deformation of the heat-conducting elastic material" means that the heat-conducting plate itself does not deform, but movement in accordance with the deformation of the heat-conducting elastic material (for example, movement in the thickness direction of the plate-like member) is possible.

[0014] The plate-shaped member may have a laminated structure consisting of a heat-conducting elastic body and heat-conducting plates arranged on both sides of the heat-conducting elastic body.

[0015] The material of the heat-conducting elastic body and heat-conducting plate included in the plate-shaped 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-conducting elastic body and heat-conducting plate is preferably 10 W / (m·K) or higher, more preferably 50 W / (m·K) or higher, and even more preferably 100 W / (m·K) or higher. Examples of materials with excellent thermal conductivity include metals, carbon, and silicon. Among these, metals are preferred from the viewpoint of strength and processability.

[0016] Specifically, examples of metals include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys containing the aforementioned metals. Among these metals, copper, aluminum, and their alloys are preferred from the viewpoint of thermal conductivity and economic efficiency. From the viewpoint of weight reduction, aluminum and aluminum alloys are preferred.

[0017] Specific examples of heat-conducting elastic materials included in plate-shaped members include metal sponges and aggregates of metal fibers. A specific example of a heat-conducting plate included in a plate-shaped member is a metal plate.

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

[0019] The plate-shaped member may have a channel for circulating the refrigerant inside. If the thermally conductive elastic material has a porous structure, the voids within the porous structure may be used as a channel for the refrigerant. The refrigerant may be either a liquid or a gas.

[0020] (Enclosure) The housing that constitutes the battery module is not particularly limited as long as it is capable of accommodating multiple battery cells. From the viewpoint of achieving sufficient heat dissipation, the thermal conductivity of the enclosure material is preferably 10 W / (m·K) or higher, more preferably 50 W / (m·K) or higher, and even more preferably 100 W / (m·K) or higher. Materials with excellent thermal conductivity include metals, carbon, and silicon. Among these, metals are preferred from the viewpoint of strength and processability.

[0021] Specifically, examples of metals include aluminum, copper, iron, nickel, gold, silver, platinum, cobalt, zinc, lead, tin, titanium, chromium, aluminum, magnesium, manganese, and alloys containing the aforementioned metals. Among these metals, copper, aluminum, and their alloys are preferred from the viewpoint of thermal conductivity and economic efficiency. From the viewpoint of weight reduction, aluminum and aluminum alloys are preferred.

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

[0023] The housing may have a side wall surrounding the space for housing the battery cells that includes at least a portion of a thermally conductive elastic material. For example, if the shape of the space in the housing that houses the battery cells is a rectangle surrounded by two pairs of opposing side walls, then at least one pair of opposing side walls may contain a thermally conductive elastic material. The state in which the side wall includes a thermally conductive elastic material includes cases where the thermally conductive elastic material is contained inside the side wall, and cases where the thermally conductive elastic material is arranged so as to be in contact with the inner wall surface of the side wall (the surface on the side of the space that houses the battery). The side wall containing the heat-conducting elastic material may also include a heat-conducting plate together with the heat-conducting elastic material.

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

[0025] An example of the configuration of a container housing a battery cell will be described below with reference to the drawings. However, the embodiments of this disclosure are not limited to the configurations shown in the following drawings. Furthermore, the sizes of the components shown in the drawings and the relative sizes of the components are conceptual, and the embodiments of this disclosure are not limited to these.

[0026] The battery module 10 shown in Figure 1 consists of a plurality of battery cells 11, a housing 12 that houses the battery cells 11, and plate-shaped members 13 that divide the space in the housing 12 where the battery cells 11 are housed into a plurality of spaces. The plate-shaped member 13 is composed of a heat-conducting elastic body 13a and heat-conducting plates 13b arranged on both sides of the heat-conducting elastic body 13a.

[0027] In the battery module 10 shown in Figure 1, if an explosion or fire occurs in one of the battery cells 11, the plate-shaped member 13 prevents the flame from spreading to battery cells 11 located in the space where the affected battery cell 11 is not located. Furthermore, the heat generated within the battery cell 11 is conducted from the plate-shaped member 13 to the housing 12 and dissipated to the outside of the battery module 10. The plate-shaped member 13 contains a thermally conductive elastic body 13a and is elastically deformable, so that it is always kept in close contact with the adjacent battery cell 11.

[0028] (Battery cell) The battery cells included in the battery module of this disclosure are not particularly limited as long as they can be housed in a container. From the viewpoint of heat dissipation efficiency, the shape of the battery cell is preferably such that a sufficient contact area with the plate-shaped member is secured. An example of such a battery cell is a battery in which the electrode body is covered with a metallic laminate film (a so-called laminate cell).

[0029] The types of battery cells included in the battery module of this disclosure are not particularly limited. Battery cells can be selected from secondary batteries such as lithium-ion secondary batteries (including liquid-based batteries and all-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, etc., the battery cell may be a lithium-ion secondary battery.

[0030] A lithium-ion secondary battery comprises, for example, a positive electrode, a negative electrode, a separator placed between the positive and negative electrodes as needed, and an electrolyte.

[0031] The positive electrode comprises, for example, a current collector and a positive electrode layer placed on the current collector. The positive electrode layer contains a positive electrode material. Examples of positive electrode active materials include lithium-transition metal composite oxides (hereinafter also referred to as lithium transition metal composite oxides). Examples of transition metals include Ni, Co, Mn, Al, B, Mg, Ti, V, Cr, Fe, Cu, Zn, Ga, Sr, Zr, Nb, In, Sn, Ta, and W. Examples of lithium transition metal composite oxides include layered lithium transition metal composite oxides, spinel-type lithium transition metal composite oxides, and olivine-type lithium transition metal composite oxides. Examples of layered lithium transition metal composite oxides include those containing at least one transition metal selected from Ni, Co, and Mn. Specifically, LiNi a Co b Mn c Examples include compounds represented by the structural formula of O2 (where a, b, and c are each numbers between 0 and 1, and a+b+c=1), and 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 aforementioned compound. A specific example of a spinel-type lithium transition metal composite oxide is LiMn2O4. Specific examples of olivine-type lithium transition metal composite oxides include LiMPO4 (M: Fe, Co, Ni, or Mn). The positive electrode active material contained in the positive electrode material may be a single type or two or more types. The positive electrode layer may contain components such as conductive additives and binders in addition to the positive electrode active material. Materials that can be used to construct the positive electrode current collector include aluminum, aluminum alloy, nickel, titanium, and stainless steel. The shape of the current collector can include foil, mesh, etc.

[0032] The negative electrode comprises, for example, a current collector and a negative electrode layer disposed on the current collector and containing a negative electrode active material. Examples of negative electrode active materials include carbon materials such as graphite, hard carbon, soft carbon, and activated carbon, as well as silicon, metallic lithium, lithium alloys, and lithium titanate (LTO). The negative electrode layer may contain components such as conductive additives and binders in addition to the negative electrode active material. The materials used to construct the negative electrode current collector include copper, copper alloys, nickel, titanium, and stainless steel. The shape of the negative electrode current collector can be foil, mesh, etc.

[0033] Examples of separators include nonwoven fabrics, cloths, and microporous films mainly composed of polyolefins such as polyethylene and polypropylene. When a lithium-ion secondary battery uses a solid electrolyte, a separator may not be necessary.

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

[0035] The battery module of this disclosure may be installed in an electric vehicle. An example of applying the battery module of this disclosure to an electric vehicle will be described below with reference to the drawings. In the following description, "battery pack 10" refers to a structure containing multiple battery modules.

[0036] Figure 2 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. As shown in Figure 2, the vehicle 100 is a battery electric vehicle (BEV) with the battery pack 10 mounted under the floor. In each figure, the arrows UP, FR, and LH indicate the upper side in the vertical direction of the vehicle, the front side in the longitudinal direction of the vehicle, and the left side in the width direction of the vehicle, respectively. When describing the directions of front, rear, left, right, up, and down, unless otherwise specified, they refer to the front and rear in the longitudinal direction of the vehicle, the left and right in the width direction of the vehicle, and the up and down in the vertical direction of the vehicle.

[0037] In this embodiment, the vehicle 100, as an example, has a DC / DC converter 102, an electric compressor 104, and a PTC (Positive Temperature Coefficient) heater 106 positioned in front of the battery pack 10. The motor 108, gearbox 110, inverter 112, and charger 114 are positioned behind the battery pack 10.

[0038] The DC current output from the battery pack 10 is voltage-adjusted by the DC / DC converter 102 and then supplied to the electric compressor 104, PTC heater 106, inverter 112, etc. Power is also supplied to the motor 108 via the inverter 112, causing the rear wheels to rotate and the vehicle 100 to move.

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

[0040] The arrangement and structure of the components constituting the vehicle 100 are not limited to the configuration described above. For example, it may be applied to a hybrid vehicle (HV) or a plug-in hybrid electric vehicle (PHEV) equipped with an engine. In this embodiment, the motor 108 is mounted at the rear of the vehicle and it is a rear-wheel drive vehicle, but it is not limited to this, and it may be a front-wheel drive vehicle with the motor 108 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, it may be a vehicle equipped with in-wheel motors for each wheel.

[0041] The battery pack 10 is composed of multiple battery modules 11. In this embodiment, as an example, 10 battery modules 11 are provided. Specifically, 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the right side of the vehicle 100, and 5 battery modules 11 are arranged in the longitudinal direction of the vehicle on the left side of the vehicle 100. Furthermore, each battery module 11 is electrically connected.

[0042] Figure 3 is a schematic perspective view of the battery module 11. As shown in Figure 3, the battery module 11 is formed in a roughly rectangular parallelepiped shape with the vehicle width direction as the longitudinal direction. The outer shell of the battery module 11 is made of aluminum alloy. For example, the outer shell of the battery module 11 is formed by joining aluminum die-cast parts to both ends of an aluminum alloy extruded 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, busbars (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 longitudinal direction is, for example, 150 mm to 250 mm, and the height MH in the vehicle vertical direction is, for example, 80 mm to 110 mm.

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

[0046] A flexible printed circuit board (FPC) 21 is placed on top of the battery cell 20. The flexible printed circuit board 21 is formed in a strip shape with the vehicle width direction as its longitudinal direction, and thermistors 23 are provided at both ends of the flexible printed circuit board 21. The thermistors 23 are not bonded to the battery cell 20, but are pressed toward the battery cell 20 by the upper cover of the battery module 11.

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

[0048] Figure 5 is a schematic view of a battery cell 20 housed in a battery module 11, viewed from the thickness direction. As shown in Figure 5, the battery cell 20 is formed in a roughly rectangular plate shape, and an electrode body (not shown) is housed inside. The electrode body is composed of a positive electrode, a negative electrode, and a separator stacked together, and is sealed with a laminate film 22.

[0049] In this embodiment, as an example, the electrode housing is formed by folding and bonding an embossed sheet-like laminate film 22. While both a single-cup embossed structure (with one embossed area) and a double-cup embossed structure (with two embossed areas) can be employed, this embodiment uses a single-cup embossed structure with a fold depth of approximately 8mm to 10mm.

[0050] The upper ends of both longitudinal ends of the battery cell 20 are bent, and the corners form the outer shape. In addition, the upper end of the battery cell 20 is bent, and a fixing tape 24 is wrapped around the upper end of the battery cell 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 a position offset below the vertical center of the battery cell 20. The terminals 26 are joined to a busbar (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, 530mm~600mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The length CW2 of the area where the electrode body is housed is, for example, 500mm~520mm, 600mm~700mm, 700mm~800mm, 800~900mm, and 1000mm or more. The height CH of the battery cell 20 is, for example, 80mm~110mm and 110mm~140mm. The thickness of the battery cell 20 is 5.0mm~7.0mm, 7.0mm~9.0mm, and 9.0mm~11.0mm. The height TH of the terminal 26 is 40mm~50mm, 50mm~60mm, and 60mm~70mm. [Explanation of Symbols]

[0053] 10: Battery Module 11: Battery cell 12: Cabinet 13: Plate-shaped member 13a: Thermally conductive elastic material 13b: Heat conductive plate

Claims

1. Multiple battery cells, The battery comprises a container for housing the aforementioned battery cell, The container includes a housing for housing battery cells and a plate-shaped member that is thermally connected to the housing and divides the space in the housing where the battery cells are housed into a plurality of spaces. The plate-shaped member includes a heat-conducting elastic body and a heat-conducting plate disposed on one or both sides of the heat-conducting elastic body, wherein the heat-conducting elastic body has a porous structure, and the plate-shaped member is compressed by the battery cell. Battery module.

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

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

4. The battery module according to claim 1 or claim 2, wherein the shape of the space for housing the battery cells in the housing is a rectangle surrounded by two pairs of opposing side walls, and at least one pair of opposing side walls includes a thermally conductive elastic material.

5. The battery module according to claim 1 or claim 2, wherein the plate-shaped member has a flow path for circulating a refrigerant inside.

Images