Battery module

Abstract

To provide a battery module that can efficiently dissipate heat generated from a battery cell.SOLUTION: A battery module 1 includes a stack 10 including battery cells 30 and spacers 40 stacked alternately in one direction, through holes provided at corners of the spacers 40 in the stacking direction of the battery cells 30 and spacers 40, and rod-shaped members 20 inserted into the through holes, and the spacers 40 are arranged in contact with both side surfaces of the battery cells 30 along the stacking direction, and the spacers 40 have hollow portions at their edges in a direction perpendicular to the stacking direction, the hollow portions having a refrigerant flow path therein.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Batteries using lithium metal anodes, etc., may experience cell expansion during charging. In particular, battery modules that include stacks of multiple battery cells are designed with this effect in mind.

[0003] A known example of a battery module that suppresses battery expansion includes a stack including a plurality of battery cells stacked on top of each other along a first direction, a pair of restraining and fixing mechanisms that apply a restraint load to the stack along the first direction and fix the stack to a fixed member at both ends of the stack in the first direction, and a fixing member that is disposed between the pair of restraining and fixing mechanisms and fixes the stack to the fixed member, wherein the restraining and fixing mechanisms fix the stack to the fixed member so that the battery cells can slide along the first direction while resisting the restraint load, and the restraining and fixing mechanism has a restraint section that is arranged together with the battery cells along the first direction and applies the restraint load to the stack, and a second fixing section that is fixed to the fixed member by a bolt and thereby fixes the stack to the fixed member, an elastic member is disposed between the second fixing section and the bolt, and the second fixing section is fixed by a force corresponding to the amount of compression of the elastic member (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6794709 Summary of the Invention [Problem to be solved by the invention]

[0005] However, although the battery module in Patent Document 1 can suppress deflection caused by expansion of the battery cells, it cannot efficiently dissipate the heat generated by the battery cells. If the heat generated by the cells increases during charging and discharging, this may lead to deterioration of battery performance.

[0006] The present invention has been made in consideration of the above circumstances, and aims to provide a battery module that can efficiently dissipate heat generated from battery cells, thereby contributing to stabilizing battery performance, improving quality control in the manufacturing process, and ultimately improving energy efficiency. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides the following means. [1] A stack including battery cells and spacers stacked alternately along one direction; a through-hole provided in a corner of the spacer in a stacking direction of the battery cell and the spacer, and a rod-shaped member inserted into the through-hole; the spacers are arranged in contact with both side surfaces of the battery cells along the stacking direction, the spacer has a cavity extending in a direction perpendicular to the stacking direction at an edge portion in the direction perpendicular to the stacking direction, The battery module has a coolant flow path provided in the cavity.

[0008] The spacer has through-holes at its corners in the stacking direction of the battery cells and spacers, and a rod-shaped member inserted through the through-hole, allowing the battery cells and spacers to move along the member. The spacers are arranged in contact with both side surfaces of the battery cells along the stacking direction, and the spacers have cavities extending in a direction perpendicular to the stacking direction at their edges perpendicular to the stacking direction, with refrigerant flow paths provided within the cavities. Heat from the battery cells is transferred via the spacers to the refrigerant flowing within the refrigerant flow paths, allowing heat generated by the battery cells to be efficiently released, thereby providing a significant cooling effect for the battery cells.

[0009] [2] The battery module according to [1], wherein a heat transfer filler is disposed between the cavity and the refrigerant flow path.

[0010] By placing a heat transfer filler between the cavity and the refrigerant flow path, the cavity and the refrigerant flow path are tightly connected via the heat transfer filler, and heat from the battery cell is transferred to the refrigerant flow path via the spacer, thereby achieving a significant cooling effect for the battery cell.

[0011] [3] The battery module according to [1] or [2], wherein the hollow portion is disposed in a position that does not face the battery cell.

[0012] By arranging the hollow portion at a position that does not face the battery cells, the battery cells can be cooled while increasing the energy density of the battery cells in the width direction of the battery module.

[0013] [4] The battery module according to any one of [1] to [3], wherein the spacer includes a heat shield sheet and a pair of heat transfer plates that sandwich the heat shield sheet.

[0014] The spacer has a heat shield sheet and a pair of heat transfer plates that sandwich the heat shield sheet, which can prevent multiple explosions and improve insulation performance between battery cells. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide a battery module that can efficiently release heat generated from battery cells. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a cross-sectional view showing a battery module according to an embodiment of the present invention. [Figure 2] 1 is a perspective view showing a battery module according to an embodiment of the present invention. [Figure 3]1 is a cross-sectional view showing a spacer and a battery cell that constitute a battery module according to an embodiment of the present invention. [Figure 4] 1 is a cross-sectional view showing a spacer that constitutes a battery module according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0018] [Battery module] Fig. 1 is a cross-sectional view showing a battery module according to one embodiment of the present invention. Fig. 2 is a perspective view showing a battery module according to one embodiment of the present invention. Fig. 3 is a cross-sectional view showing a spacer and a battery cell that constitute a battery module according to one embodiment of the present invention. Fig. 4 is a cross-sectional view showing a spacer that constitutes a battery module according to one embodiment of the present invention. Note that the drawings used in the following description may conveniently show characteristic portions in an enlarged manner to make the characteristics easier to understand, and the dimensional ratios of the components are not limited to those shown.

[0019] 1 and 2, the battery module 1 of this embodiment includes a stack 10 and rod-shaped members (hereinafter referred to as "rod-shaped members") 20. The stack 10 includes battery cells 30 and spacers 40 stacked alternately in one direction. The rod-shaped members 20 are inserted into through-holes 41 provided at corners of the spacers 40 in the stacking direction of the battery cells 30 and spacers 40.

[0020] The spacers 40 are arranged in contact with both side surfaces 30a of the battery cells 30 along the stacking direction.

[0021] [Rod-shaped member] The rod-shaped members 20 are inserted into the through-holes 41 of the spacer 40 to hold the battery cells 30. There are no particular limitations on the shape of the cross section perpendicular to the longitudinal direction of the rod-shaped members 20, but a circular shape is preferable so that the spacer 40 can be easily moved along the longitudinal direction of the rod-shaped members 20 while inserted into the through-holes 41 of the spacer 40.

[0022] The material of the rod-shaped member 20 is not particularly limited, but may be, for example, an insulating material.

[0023] [Battery cell] Each battery cell 30 has an electrode stack, an exterior film 31 that covers the outer surface of the electrode stack and houses the electrode stack, and an electrode tab 32. As shown in Fig. 1, the electrode tabs 32 of two adjacent battery cells 30 are connected via a bus bar 50 with a spacer 40 between them.

[0024] The electrode stack includes a positive electrode, a negative electrode, and an electrolyte layer.

[0025] (positive electrode) The positive electrode is formed by laminating a first current collector layer and a first active material layer containing at least a positive electrode active material. In this embodiment, the positive electrode has the first current collector layer and the first active material layer formed on both main surfaces of the first current collector layer.

[0026] The first current collector layer is preferably made of at least one material with high electrical conductivity. Examples of highly conductive materials include metals or alloys containing at least one of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), aluminum (Al), chromium (Cr), and nickel (Ni), as well as non-metals such as carbon (C). Considering both high conductivity and manufacturing costs, aluminum, nickel, and stainless steel are preferred. Furthermore, aluminum is less likely to react with the positive electrode active material and electrolyte. Therefore, using aluminum for the first current collector layer can reduce the internal resistance of the battery.

[0027] The first current collector layer may be in the form of, for example, a foil, a plate, a mesh, a nonwoven fabric, a foam, etc. In order to improve adhesion to the first active material layer, carbon or the like may be disposed on the surface of the first current collector layer, or the surface may be roughened.

[0028] The first active material layer contains a positive electrode active material that donates and receives lithium ions and electrons. The positive electrode active material is not particularly limited as long as it is a material that can reversibly release and absorb lithium ions and transport electrons, and known positive electrode active materials that can be used for the positive electrode of lithium ion batteries can be used. For example, lithium cobalt oxide (LiCoO2), lithium nickel oxide (LiNiO2), lithium manganese oxide (LiMn2O4), solid solution oxide (Li2MnO3-LiMO2 (M = Co, Ni, etc.)), lithium-manganese-nickel-cobalt oxide (LiNi x Mn y Co z O2, x+y+z=1), composite oxides such as olivine-type lithium phosphate (LiFePO4); conductive polymers such as polyaniline and polypyrrole; sulfides such as Li2S, CuS, Li-Cu-S compounds, TiS2, FeS, MoS2, and Li-Mo-S compounds; mixtures of sulfur and carbon; etc. The positive electrode active material may be composed of one kind of the above materials alone, or may be composed of two or more kinds.

[0029] The first active material layer contains an electrolyte that transfers lithium ions to and from the positive electrode active material. The electrolyte is not particularly limited as long as it has lithium ion conductivity, and materials commonly used in lithium ion batteries can be used. Examples of the electrolyte include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based solid electrolytes containing lithium-containing salts and lithium-ion conductive ionic liquids. Among these, sulfide solid electrolyte materials are preferred from the viewpoints of high lithium ion conductivity, good structural formability by pressing, and good interfacial bonding. The electrolyte may be composed of one kind of the above materials alone or two or more kinds of them. The electrolyte contained in the first active material layer may be the same material as the electrolyte contained in the second active material layer or the solid electrolyte layer, or may be a different material.

[0030] The first active material layer may contain a conductive additive to improve the conductivity of the positive electrode. The conductive additive may be any conductive additive generally used in lithium-ion batteries. Examples of the conductive additive include carbon black such as acetylene black and Ketjen black; carbon fiber; vapor-grown carbon fiber; graphite powder; and carbon materials such as carbon nanotubes. The conductive additive may be composed of one or more of the above materials.

[0031] The first active material layer may also contain a binder that functions to bind the positive electrode active materials together and between the positive electrode active material and the first current collector layer.

[0032] The first active material layer may be formed on both main surfaces of the first current collector layer, or on only one main surface of the first current collector layer. When the positive electrode is a single-sided coated electrode, a laminated positive electrode formed by stacking two positive electrodes with their current collector surfaces facing each other may be used as a double-sided coated electrode. When the first current collector layer has a three-dimensional porous structure such as a mesh, nonwoven fabric, or foam, the first current collector layer may be provided integrally with the first active material layer.

[0033] The first current collector layers are assembled at one end in the width direction of the all-solid-state battery. The first active material layer is in contact with the electrolyte layer and may contain sulfides contained in the electrolyte layer.

[0034] (Negative electrode) The negative electrode has at least a second active material layer containing a negative electrode active material.

[0035] The second current collector layer contains at least copper (Cu). Like the first current collector layer, the second current collector layer may contain a material other than copper that has high conductivity. Examples of highly conductive materials other than copper include metals or alloys containing at least one of silver (Ag), palladium (Pd), gold (Au), platinum (Pt), chromium (Cr), and nickel (Ni), or non-metals such as carbon (C). Considering not only high conductivity but also manufacturing costs, nickel or stainless steel is preferred as the material other than copper. Furthermore, stainless steel is less likely to react with the positive electrode active material, negative electrode active material, and electrolyte. Therefore, using stainless steel for the second current collector layer can reduce battery manufacturing costs.

[0036] The second current collector layer may be in the form of, for example, a foil, a plate, a mesh, a nonwoven fabric, a foam, etc. In order to improve adhesion to the second active material layer, carbon or the like may be disposed on the surface of the second current collector layer, or the surface may be roughened.

[0037] The second active material layer contains a negative electrode active material that donates and accepts lithium ions and electrons. The negative electrode active material is not particularly limited as long as it is a material that can reversibly absorb and release lithium ions and transport electrons, and known negative electrode active materials that can be used for the negative electrode of a lithium ion battery can be used. Examples of such materials include carbonaceous materials such as natural graphite, artificial graphite, resin carbon, carbon fiber, activated carbon, hard carbon, and soft carbon; alloy-based materials mainly composed of tin, tin alloys, silicon, silicon alloys, gallium, gallium alloys, indium, indium alloys, aluminum, and aluminum alloys; conductive polymers such as polyacene, polyacetylene, and polypyrrole; metallic lithium; lithium titanium composite oxides (e.g., Li4Ti5O 12 ), Sn—Li alloy, Ag—Li alloy, Mg—Li alloy, In—Li alloy, Si—Li alloy, Al—Li alloy, etc. These negative electrode active materials may be composed of one kind of the above materials alone, or may be composed of two or more kinds of the above materials.

[0038] The second active material layer contains an electrolyte that transfers lithium ions to and from the negative electrode active material. The electrolyte is not particularly limited as long as it has lithium ion conductivity, and materials generally used in lithium ion batteries can be used. Examples of the electrolyte include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based solid electrolytes containing lithium-containing salts and lithium-ion conductive ionic liquids. The electrolyte may be composed of one or more of the above materials. The electrolyte contained in the second active material layer may be the same as or different from the electrolyte contained in the first active material layer or the solid electrolyte layer.

[0039] The second active material layer may contain a conductive additive, a binder, etc. These materials are not particularly limited, and may be, for example, the same materials as those used in the first active material layer described above.

[0040] The second active material layer may be formed on both main surfaces of the second current collector layer, or on only one main surface of the second current collector layer. When the second current collector layer has a three-dimensional porous structure such as a mesh, nonwoven fabric, or foam, the second current collector layer may be provided integrally with the second active material layer.

[0041] (electrolyte layer) The electrolyte layer is disposed between the first active material layer and the second active material layer.

[0042] The electrolyte is not particularly limited as long as it has lithium ion conductivity and insulating properties, and materials generally used in lithium ion batteries can be used. Examples include inorganic solid electrolytes such as sulfide solid electrolyte materials, oxide solid electrolyte materials, halide solid electrolytes, and lithium-containing salts, polymer-based solid electrolytes such as polyethylene oxide, and gel-based electrolytes containing lithium-containing salts and lithium ion-conductive ionic liquids. Among these, sulfide solid electrolyte materials are preferred from the viewpoints of high lithium ion conductivity, structural formability by pressing, and interfacial bonding. The form of the electrolyte material is not particularly limited, but may be, for example, in the form of particles.

[0043] The electrolyte layer may contain an adhesive to impart mechanical strength and flexibility.

[0044] The electrolyte layer may be in the form of a sheet having a porous substrate and a solid electrolyte supported on the porous substrate. The form of the porous substrate is not particularly limited, and examples thereof include woven fabric, nonwoven fabric, mesh cloth, porous membrane, expanded sheet, and punched sheet. Among these forms, nonwoven fabric is preferred from the viewpoint of handleability, which allows for a higher loading of solid electrolyte.

[0045] The porous substrate is preferably made of an insulating material, which can improve the insulation of the electrolyte layer. Examples of insulating materials include resin materials such as nylon, polyester, polyethylene, polypropylene, polytetrafluoroethylene, ethylene-tetrafluoroethylene copolymer, polyvinylidene fluoride, polyvinylidene chloride, polyvinyl chloride, polyurethane, vinylon, polybenzimidazole, polyimide, polyphenylene sulfite, polyether ether ketone, cellulose, and acrylic resin; natural fibers such as hemp, wood pulp, and cotton linter; and glass.

[0046] (exterior film) The exterior film 31 is a laminated film having an inner resin layer, a metal layer, and an outer resin layer. Examples of resins that make up the inner and outer resin layers include polyester resins such as polyethylene terephthalate (PET). The metal layer is made of, for example, aluminum foil.

[0047] [Spacer] The spacer 40 has through holes 41 provided in the corners of the spacer 40 in the stacking direction. The through holes 41 need only be provided in at least two corners of the spacer 40, and may be provided in all four corners of the spacer 40. Each of the two edge portions 40a in a direction perpendicular to the stacking direction has a cavity 42 extending in a direction perpendicular to the stacking direction. Furthermore, a refrigerant flow path 43 is provided in each of the cavity portions 42. Water, for example, flows through the refrigerant flow path 43 as a refrigerant. The cavity 42 may be provided on one of the edge portions 40a.

[0048] 4, it is preferable that a heat transfer filler 44 is disposed between the cavity 42 and the refrigerant flow path 43 in the spacer 40. By disposing the heat transfer filler 44 between the cavity 42 and the refrigerant flow path 43, the cavity 42 and the refrigerant flow path 43 are tightly connected via the heat transfer filler 44, and heat from the battery cells 30 is transferred to the refrigerant flow path 43 via the spacer 40, thereby achieving a significant cooling effect for the battery cells 30. Examples of the heat transfer filler 44 include aluminum oxide (Al2O3), silicon oxide (SiO2), magnesium oxide (MgO), boron nitride (BN), and aluminum nitride (AlN).

[0049] 2 and 4, the cavity 42 of the spacer 40 is preferably disposed in a position that does not face the battery cells 30. That is, the cavity 42 is preferably disposed at each of the two edge portions 40a in the direction perpendicular to the stacking direction. In this way, the energy density of the battery cells 30 in the width direction of the battery module 1 can be increased while the battery cells 30 can be cooled.

[0050] As shown in FIG. 4, the spacer 40 has a heat shield sheet 45 and a pair of heat transfer plates 46 that sandwich the heat shield sheet 45 from both side surfaces 45a thereof. An example of the heat shield sheet 45 is a mica sheet. The mica sheet is an insulating sheet made by integrating mica, a mineral whose main components are silicon (Si), aluminum (Al), magnesium (Mg), and potassium (K), with a silicone adhesive. The heat transfer plate 46 is not particularly limited as long as it has excellent thermal conductivity, and may be made of an aluminum plate, for example. By configuring the spacer 40 in this way, it is possible to prevent multiple explosions and improve the insulation performance between the battery cells 30.

[0051] "Reaction force generator" As shown in FIG. 1, in the battery module 1 of this embodiment, a reaction force generator 60 is preferably interposed between the stacked battery cells 30 and the spacers 40.

[0052] According to the battery module 1 of this embodiment, the spacers 40 are provided with through holes 41 at their corners in the stacking direction of the battery cells 30 and spacers 40, and rod-shaped members 20 inserted through the through holes 41, allowing the battery cells 30 and spacers 40 to move along the rod-shaped members 20. The spacers 40 are arranged in contact with both side surfaces of the battery cells 30 along the stacking direction, and the spacers 40 have hollow portions 42 extending in a direction perpendicular to the stacking direction at their edge portions 40a perpendicular to the stacking direction, and refrigerant flow paths 43 are provided within the hollow portions 42. As a result, heat from the battery cells 30 is transferred via the spacers 40 to the refrigerant flowing within the refrigerant flow paths 43, allowing the heat generated by the battery cells 30 to be efficiently released, thereby achieving a significant cooling effect for the battery cells 30.

[0053] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications and variations are possible within the scope of the gist of the present invention as set forth in the claims. [Explanation of symbols]

[0054] 1 Battery Module 10 Laminate 20 Rod-shaped member (rod-shaped member) 30 battery cells 31 Exterior film 32 Electrode tab 40 spacer 41 Through hole 42 Cavity 43 Refrigerant flow path 44 Heat Transfer Filler 45 Heat-shielding sheet 46 Heat transfer plate 50 busbar 60 Reaction Force Generator

Claims

1. a stack including battery cells and spacers stacked alternately along one direction; a through-hole provided in a corner of the spacer in a stacking direction of the battery cell and the spacer, and a rod-shaped member inserted into the through-hole; the spacers are arranged in contact with both side surfaces of the battery cells along the stacking direction, the spacer has a cavity extending in a direction perpendicular to the stacking direction at an edge portion in the direction perpendicular to the stacking direction, The battery module has a coolant flow path provided in the cavity.

2. The battery module according to claim 1 , wherein a heat transfer filler is disposed between the cavity and the coolant flow path.

3. The battery module according to claim 1 , wherein the cavity is disposed at a position that does not face the battery cell.

4. The battery module according to claim 1 , wherein the spacer comprises a heat shield sheet and a pair of heat transfer plates sandwiching the heat shield sheet.

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