Battery module

Abstract

To provide a battery module capable of increasing uniformity of a surface pressure applied to a battery cell.SOLUTION: A battery module includes: a battery cell stacked body in which a plurality of battery cells 11a are stacked; a pair of end plates provided at both ends of the battery cell stacked body in a stacking direction; and a cushion member 14 disposed between the plurality of battery cells 11a and between the battery cell stacked body and the end plates. In the cushion member 14, concave parts and convex parts are alternately arranged continuously, a plurality of wave-shaped plate springs W extending in a predetermined direction is laminated in a lamination direction of the battery cell stacked body, and the concave parts and the convex parts of the adjacent wave-shaped plate springs W are in opposed contact with each other. In the battery module, a soft resin S having a hardness of E40 or less or E60 or more is present on an outer surface of the battery cell 11a facing the cushion member 14.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] In recent years, research and development has been conducted on battery modules that contribute to energy efficiency in order to ensure that many people have access to affordable, reliable, sustainable and advanced energy.

[0003] The battery module includes, for example, a battery cell stack in which a plurality of battery cells are stacked. Here, since the battery cells expand and contract as they are charged and discharged, the battery module includes, for example, a pair of end plates provided at both ends of the battery cell stack in the stacking direction, and a bind bar that restrains the battery cell stack between the pair of end plates.

[0004] Patent Document 1 describes an energy storage device including an energy storage module including a plurality of energy storage cells stacked in a stacking direction, a housing case that houses the energy storage module, and a limiting unit arranged between the energy storage cells. Here, the limiting unit includes a first flat plate and a second flat plate spaced apart in the stacking direction, and a corrugated plate arranged between the first flat plate and the second flat plate. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-156427 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the energy storage device described in Cited Document 1, when the limiting unit is compressed as the energy storage cells expand during charging, the difference in surface pressure between the portions of the first and second flat plates that are in contact with the corrugated plates and the portions of the first and second flat plates that are not in contact with the corrugated plates becomes large, resulting in a decrease in the uniformity of the surface pressure applied to the energy storage cells.

[0007] An object of the present invention is to provide a battery module that can increase the uniformity of the surface pressure applied to the battery cells. [Means for solving the problem]

[0008] (1) A battery module comprising: a battery cell stack in which a plurality of battery cells are stacked; a pair of plate-shaped members provided at both ends of the battery cell stack in the stacking direction; and a cushioning material disposed between the plurality of battery cells and / or between the battery cell stack and the plate-shaped members, wherein the cushioning material has concave and convex portions arranged alternately and continuously, and includes a wavy leaf spring extending in a predetermined direction; and wherein a soft resin having a hardness of E40 or less or E60 or more is present on the outer or inner surface of the battery cells facing the cushioning material.

[0009] (2) The battery module according to (1), wherein the soft resin is a thermoplastic elastomer, rubber, or hardened resin.

[0010] (3) The battery module according to (1) or (2), wherein the cushioning material is formed by stacking multiple layers of the corrugated leaf springs in the stacking direction of the battery cell stack, and the recesses and protrusions of adjacent corrugated leaf springs are in opposing contact with each other.

[0011] (4) The battery module according to any one of (1) to (3), wherein the battery cells are solid-state battery cells.

[0012] (5) A method for manufacturing a battery module according to any one of (1) to (4), comprising the step of applying a coating liquid containing the soft resin or a precursor of the soft resin to a surface of the battery cell facing the cushion material.

[0013] (6) The method for manufacturing a battery module described in (5), wherein the precursor of the soft resin is an ultraviolet-curable resin, and further includes a step of irradiating ultraviolet light onto a surface onto which a coating liquid containing the ultraviolet-curable resin has been applied. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a battery module that can increase the uniformity of the surface pressure applied to the battery cells. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view showing a battery module according to an embodiment of the present invention. [Figure 2] FIG. 2 is a partially enlarged view of the battery module of FIG. [Figure 3] FIG. 3 is an enlarged view of the wavy leaf spring of FIG. 2. [Figure 4] 3 is a cross-sectional view showing a modified example of the battery module of FIG. 2. FIG. [Figure 5] 3 is a graph showing the relationship between the hardness of the soft resin in FIG. 2 and the variation in surface pressure. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0017] FIG. 1 shows a battery module according to one embodiment of the present invention.

[0018] The battery module 10 includes a battery cell stack 11 in which a plurality of battery cells 11a are stacked, end plates 12 as a pair of plate-like members provided at both ends of the battery cell stack 11 in the stacking direction, and bind bars 13 as restraining members that restrain the battery cell stack 11 between the pair of end plates 12. Here, the bind bars 13 are installed in two places, at the top and bottom in the drawing.

[0019] In the battery module 10, cushioning materials 14 are arranged between the plurality of battery cells 11a and between the battery cell stack 11 and the end plate 12.

[0020] The cushioning material 14 may be disposed between the plurality of battery cells 11 a or between the battery cell stack 11 and the end plate 12.

[0021] As shown in FIG. 2, the cushion material 14 is formed by stacking corrugated leaf springs W in the stacking direction of the battery cell stack 11. Furthermore, the battery cells 11a have soft resin S with a hardness of E40 or less or E60 or more on the outer surface facing the cushion material 14. This reduces the hysteresis loss of the cushion material 14. As shown in FIG. 3, the corrugated leaf springs W have alternating, continuous recesses R and protrusions C, which extend in the depth direction of the drawing. The recesses R and protrusions C of adjacent corrugated leaf springs W are in contact with each other. The recesses R and protrusions C are convex toward the upper and lower sides, respectively, in the stacking direction of the battery cell stack 11.

[0022] Here, when the cushion material 14 is compressed due to the expansion of the battery cell 11a during charging, the soft resin S is interposed between the battery cell 11a and the cushion material 14, so the difference in surface pressure between the part of the soft resin S that is in contact with the cushion material 14 and the part of the soft resin S that is not in contact with the cushion material 14 becomes smaller, and the uniformity of the surface pressure applied to the battery cell 11a becomes higher.

[0023] The hardness of the soft resin S is E40 or less or E60 or more. When the hardness of the soft resin S is E40 or less or E60 or more, the uniformity of the surface pressure applied to the battery cell 11a increases. When the hardness of the soft resin S is E40 or less, the hardness of the soft resin S is, for example, E10 or more, and when the hardness of the soft resin S is E60 or more, the hardness of the soft resin S is, for example, E90 or less.

[0024] The soft resin S is not particularly limited as long as it can have a hardness of E40 or less or E60 or more, but examples thereof include thermoplastic elastomers such as polystyrene-based thermoplastic elastomers, rubbers such as isoprene rubber and silicone rubber, and cured resins such as cured products of ultraviolet-curable resins.

[0025] The thickness of the soft resin S when the charging rate of the battery cell 11a is 100% is not particularly limited, but is, for example, 0.05 mm or more and 0.1 mm or less.

[0026] The method for making the soft resin S present on the outer surface of the battery cell 11a facing the cushion material 14 is not particularly limited, but examples thereof include a method of applying a coating liquid containing the soft resin S or a precursor of the soft resin S.

[0027] The precursor of the soft resin S is not particularly limited, but examples thereof include ultraviolet curable resins. When an ultraviolet curable resin is used as the precursor of the soft resin S, the ultraviolet curable resin is cured by irradiating ultraviolet rays onto the outer surface on which a coating liquid containing the ultraviolet curable resin has been applied. The ultraviolet curable resin is not particularly limited, but examples thereof include ultraviolet curable acrylic resins and ultraviolet curable silicone resins.

[0028] The soft resin S may be present on the inner surface of the battery cell 11a that faces the cushion material 14.

[0029] The number of layers of the corrugated leaf spring W is not limited to two, but is preferably two or more and six or less, and more preferably two or more and four or less.

[0030] Furthermore, adjacent corrugated leaf springs W may have portions of the recessed portions R and protruding portions C that are in contact with each other and face each other bonded together by, for example, an elastic adhesive.

[0031] Alternatively, a wave-shaped leaf spring W may be used as the cushion material 14.

[0032] The Young's modulus of the cushion material 14 is preferably 35 GPa or more. When the Young's modulus of the cushion material 14 is 35 GPa or more, the cushion material 14 can easily absorb the change in thickness that accompanies the expansion and contraction of the battery cells 11a. The Young's modulus of the cushion material 14 is, for example, 200 GPa or less.

[0033] The material for forming the cushioning material 14 is not particularly limited, but examples thereof include metals such as stainless steel and carbon steel, resins such as epoxy resin, phenolic resin and nylon resin, and fiber reinforced plastics (FRP) such as carbon fiber reinforced plastic (CFRP) and glass fiber reinforced plastic (GFRP). Among these, FRP is preferable in consideration of the energy density of the battery module 10.

[0034] The thickness of the cushion material 14 when the charging rate of the battery cell 11a is 100% is not particularly limited, but is, for example, 2 mm or less.

[0035] In the battery module 10, an elastic member 14A may be disposed between the battery cell 11a and the soft resin S (see FIG. 4). In this case, the soft resin S is disposed on the surface of the elastic member 14A facing the cushion material 14.

[0036] The Poisson's ratio of the elastic member 14A is preferably 0.3 or less. When the Poisson's ratio of the elastic member 14A is 0.3 or less, the elastic member 14A can easily absorb the change in thickness caused by the expansion and contraction of the battery cell 11a. The Poisson's ratio of the elastic member 14A is, for example, 0 or more.

[0037] The thickness of the elastic member 14A when the charging rate of the battery cell 11a is 100% is not particularly limited, but is, for example, 0.05 mm or more and 0.1 mm or less.

[0038] The elastic member 14A is, for example, a foam having a porosity of 30% or more and 95% or less. The material constituting the foam is not particularly limited, but examples thereof include polyurethane, silicone resin, ethylene propylene rubber, styrene resin, olefin resin, polyamide, and polyester.

[0039] Fig. 5 shows the relationship between the variation in surface pressure and the hardness of the soft resin S. In this case, the variation in surface pressure means the ratio of the maximum surface pressure to the minimum surface pressure when a load of 1.0 MPa is applied with the corrugated leaf spring W and the soft resin S arranged on both sides of the elastic member 14A, and the surface pressure on the soft resin S side was measured.

[0040] From FIG. 5, it can be seen that the variation in surface pressure is reduced when the hardness of the soft resin S is E40 or less or E60 or more.

[0041] The battery cell 11a is not particularly limited, but examples thereof include solid-state battery cells such as all-solid-state lithium metal battery cells, and electrolyte battery cells such as lithium metal battery cells, etc. Among these, solid-state battery cells are preferred.

[0042] The following describes the case where the battery cell 11a is an all-solid-state lithium metal battery cell.

[0043] An all-solid-state lithium metal battery cell includes, for example, a positive electrode current collector, a positive electrode mixture layer, a solid electrolyte layer, a lithium metal layer, and a negative electrode current collector stacked in this order.

[0044] The positive electrode current collector is not particularly limited, but may be, for example, aluminum foil.

[0045] The positive electrode mixture layer contains a positive electrode active material, and may further contain a solid electrolyte, a conductive additive, a binder, and the like.

[0046] The positive electrode active material is not particularly limited as long as it can absorb and release lithium ions. For example, LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O 2、 Li(Ni) 6 / 10 Co 2 / 10 Mn 2 / 10 )O 2、 Li(Ni) 8 / 10 Co 1 / 10 Mn 1 / 10 )O 2、 Li(Ni) 0.8 Co 0.15 Al 0.05 )O 2、 Li(Ni) 1 / 6 Co 4 / 6 Mn 1 / 6 )O 2、 Li(Ni) 1 / 3 Co 1 / 3 Mn 1 / 3 )O 2、 Examples include LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, and sulfur.

[0047] The solid electrolyte constituting the solid electrolyte layer is not particularly limited as long as it is a material capable of conducting lithium ions, and examples thereof include oxide-based electrolytes and sulfide-based electrolytes.

[0048] The negative electrode current collector is not particularly limited, but may be, for example, copper foil.

[0049] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and the above-described embodiments may be modified as appropriate within the scope of the spirit of the present invention. [Explanation of symbols]

[0050] 10 Battery Module 11 Battery cell stack 11a battery cell 12 End plate 13 Binding Bar 14 Cushioning material W wavy leaf spring S Soft resin R recess C Convex part

Claims

1. a battery cell stack in which a plurality of battery cells are stacked; a pair of plate-shaped members provided at both ends of the battery cell stack in a stacking direction; a cushioning material disposed between the plurality of battery cells and / or between the battery cell stack and the plate-shaped member, The cushioning material has concave and convex portions alternately arranged in succession and includes a wave-shaped leaf spring extending in a predetermined direction; A battery module, wherein a soft resin having a hardness of E40 or less or E60 or more is present on an outer surface or an inner surface of the battery cell facing the cushion material.

2. The battery module according to claim 1 , wherein the soft resin is a thermoplastic elastomer, a rubber, or a hardened resin.

3. 3. The battery module according to claim 1, wherein the cushioning material includes a plurality of layers of the corrugated leaf springs stacked in a stacking direction of the battery cell stack, and the recesses and protrusions of adjacent corrugated leaf springs are in contact with each other.

4. The battery module according to claim 1 or 2, wherein the battery cells are solid-state battery cells.

5. A method for manufacturing the battery module according to claim 1 or 2, comprising: A method for manufacturing a battery module, comprising: applying a coating liquid containing the soft resin or a precursor of the soft resin to a surface of the battery cell facing the cushion material.

6. the precursor of the soft resin is an ultraviolet curable resin, The method for manufacturing a battery module according to claim 5 , further comprising the step of irradiating the surface coated with the coating liquid containing the ultraviolet curable resin with ultraviolet light.

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