Storage battery module

Abstract

A battery module is provided with: a battery cell laminate in which a plurality of battery cells are laminated; a pair of plate-like members provided at both ends of the battery cell laminate in the lamination direction; and a buffer material disposed between the plurality of battery cells and / or between the battery cell laminate and the plate-shaped member. Furthermore, the buffer material is provided with a wave-shaped plate spring in which concave parts and convex parts are alternately and continuously arranged and which extends in a predetermined direction, and 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 buffer material.

Description

Technical Field

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

[0002] In recent years, research and development of battery modules that contribute to improving energy efficiency have been underway to ensure that the majority of people have access to affordable, reliable, sustainable, and advanced energy.

[0003] A battery module, for example, includes a battery cell stack composed of a plurality of stacked battery cells. Since battery cells expand and contract during charging and discharging, the battery module includes, for example, a pair of end plates disposed at both ends of the battery cell stack in the stacking direction, and tie bars that constrain the battery cell stack between the end plates.

[0004] Patent Document 1 describes a power storage device comprising: a power storage module comprising a plurality of power storage cells stacked in a stacking direction; a housing housing the power storage module; and a restraining member disposed between the power storage cells. The restraining member comprises a first flat plate and a second flat plate spaced apart in the stacking direction, and a corrugated plate disposed between the first and second flat plates.

[0005] [Prior Art Literature]

[0006] (Patent Document)

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2022-156427 Summary of the Invention

[0008] [Problems to be solved by the invention]

[0009] However, in the power storage device described in Reference 1, as the battery cells expand during charging and the cells are compressed, the difference in surface pressure between the portions of the first and second flat plates that are in contact with the corrugated plate and the portions of the first and second flat plates that are not in contact with the corrugated plate increases, thereby reducing the uniformity of the surface pressure applied to the battery cells.

[0010] An object of the present invention is to provide a battery module capable of improving the uniformity of the surface pressure borne by battery cells.

[0011] [Technical means to solve the problem]

[0012] (1) A battery module comprising: a battery cell stack having a plurality of battery cells stacked thereon; a pair of plate-like members disposed at both ends of the battery cell stack in a stacking direction; and a buffer material disposed between the plurality of battery cells and / or between the battery cell stack and the plate-like members; wherein the buffer material comprises a corrugated leaf spring having concave portions and convex portions alternately and continuously disposed thereon and extending in a predetermined direction, and a soft resin having a hardness of less than E40 or greater than E60 is present on the outer surface or inner surface of the battery cell opposite to the buffer material.

[0013] (2) The battery module according to (1), wherein the soft resin is a thermoplastic elastomer, rubber, or hardened resin.

[0014] (3) The battery module according to (1) or (2), wherein the buffer material comprises a plurality of layers of the corrugated leaf springs stacked in the stacking direction of the battery cell stack, and the concave portions and the convex portions of adjacent corrugated leaf springs are in contact with each other.

[0015] (4) The battery module according to any one of (1) to (3), wherein the battery cells are solid battery cells.

[0016] (5) A method for manufacturing a battery module, which is a method for manufacturing the battery module described in any one of (1) to (4), comprising the following steps: applying a coating liquid containing the soft resin or a precursor of the soft resin on the surface of the battery cell facing the buffer material.

[0017] (6) The method for manufacturing a battery module according to (5), wherein the precursor of the soft resin is a UV curable resin, and the method for manufacturing a battery module further comprises the step of irradiating the surface coated with the coating liquid containing the UV curable resin with ultraviolet rays.

[0018] (Effects of the Invention)

[0019] According to the present invention, a battery module can be provided that can improve the uniformity of the surface pressure applied to the battery cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG. 1 is a cross-sectional view showing a battery module according to one embodiment of the present invention.

[0021] Figure 2 yes Figure 1 A partial enlarged view of the battery module.

[0022] Figure 3 yes Figure 2An enlarged view of the corrugated leaf spring.

[0023] Figure 4 It is a drawing Figure 2 A cross-sectional view of a variation of a battery module.

[0024] Figure 5 is the deviation of the surface pressure relative to Figure 2 A graph showing the relationship between the hardness of soft resin. DETAILED DESCRIPTION

[0025] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0026] Figure 1 A battery module according to one embodiment of the present invention is shown.

[0027] The battery module 10 includes a battery cell stack 11 comprising a plurality of stacked battery cells 11a; a pair of plate-shaped end plates 12 disposed at both ends of the battery cell stack 11 in the stacking direction; and connecting rods 13 serving as restraining members for restraining the battery cell stack 11 between the pair of end plates 12. The connecting rods 13 are disposed at two locations, one at the top and one at the bottom, in the figure.

[0028] In the battery module 10 , cushioning materials 14 are arranged between the plurality of battery cells 11 a and between the battery cell stack 11 and the end plates 12 .

[0029] Furthermore, the buffer 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 .

[0030] like Figure 2 As shown, the buffer material 14 is formed by stacking corrugated leaf springs W in the stacking direction of the battery cell stack 11. In addition, the battery cell 11a has a soft resin S with a hardness of E40 or less or E60 or more on the outer surface facing the buffer material 14. Therefore, the hysteresis loss of the buffer material 14 is reduced. Figure 3 As shown, the corrugated leaf spring W is continuously and alternately provided with recesses R and protrusions C, extending in the depth direction of the figure. The recesses R and protrusions C of adjacent corrugated leaf springs W are in contact with each other. Furthermore, the recesses R and protrusions C project downward and upward, respectively, in the stacking direction of the battery cell stack 11.

[0031] Here, when the buffer material 14 is compressed as the battery cell 11a expands during charging, a soft resin S is interposed between the battery cell 11a and the buffer material 14. Therefore, the difference in surface pressure between the portion of the soft resin S that contacts the buffer material 14 and the portion of the soft resin S that does not contact the buffer material 14 becomes smaller, and the uniformity of the surface pressure borne by the battery cell 11a becomes higher.

[0032] The hardness of the soft resin S is E40 or less or E60 or greater. When the hardness of the soft resin S is E40 or less or E60 or greater, the surface pressure applied to the battery cells 11a becomes more uniform. Furthermore, when the hardness of the soft resin S is E40 or less, the hardness of the soft resin S is, for example, E10 or greater. When the hardness of the soft resin S is E60 or greater, the hardness of the soft resin S is, for example, E90 or less.

[0033] The soft resin S is not particularly limited as long as it can achieve a hardness of E40 or less or E60 or more. Examples thereof include thermoplastic elastomers such as polystyrene-based thermoplastic elastomers, rubbers such as isoprene rubber and silicone rubber, and cured products of ultraviolet curable resins.

[0034] The thickness of the soft resin S when the charge rate of the battery cell 11 a is 100% is not particularly limited, and is, for example, 0.05 mm or more and 0.1 mm or less.

[0035] The method of making the soft resin S present on the outer surface of the battery cell 11 a facing the buffer material 14 is not particularly limited, and an example thereof includes a method of applying a coating liquid containing the soft resin S or a precursor of the soft resin S.

[0036] The precursor of the soft resin S is not particularly limited, and examples thereof include ultraviolet curing resins. When a ultraviolet curing resin is used as the precursor of the soft resin S, the ultraviolet curing resin is cured by irradiating the outer surface coated with a coating liquid containing the ultraviolet curing resin with ultraviolet light. The ultraviolet curing resin is not particularly limited, and examples thereof include ultraviolet curing acrylic resins and ultraviolet curing silicone resins.

[0037] Furthermore, the soft resin S may be present on the inner surface of the battery cell 11 a facing the buffer material 14 .

[0038] The number of stacked layers of the corrugated leaf springs W is not limited to 2, but is preferably 2 or more and 6 or less, and more preferably 2 or more and 4 or less.

[0039] Furthermore, portions of the concave portions R and convex portions C of the adjacent wavy leaf springs W that are in contact with each other may be bonded together using, for example, an elastic adhesive.

[0040] Alternatively, a corrugated leaf spring W may be used as the buffer member 14 .

[0041] The Young's modulus of the buffer material 14 is preferably 35 GPa or greater. A Young's modulus of 35 GPa or greater allows the buffer material 14 to easily absorb thickness changes associated with expansion and contraction of the battery cell 11a. The Young's modulus of the buffer material 14 is, for example, 200 GPa or less.

[0042] The material constituting the cushioning material 14 is not particularly limited. Examples 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). FRP is preferred, considering the energy density of the battery module 10.

[0043] The thickness of the buffer material 14 when the charge rate of the battery cell 11 a is 100% is not particularly limited, and is, for example, 2 mm or less.

[0044] In addition, the battery module 10 may also include an elastic member 14A disposed between the battery cell 11a and the soft resin S (see Figure 4 In this case, the soft resin S is present on the surface of the elastic member 14A facing the cushioning material 14 .

[0045] 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 thickness change caused by the expansion and contraction of the battery cell 11a. Alternatively, the Poisson's ratio of the elastic member 14A is, for example, 0 or greater.

[0046] The thickness of the elastic member 14A when the charge rate of the battery cell 11 a is 100% is not particularly limited, and is, for example, 0.05 mm or more and 0.1 mm or less.

[0047] The elastic member 14A is, for example, a foam having a porosity of 30% to 95%. The material constituting the foam is not particularly limited, and examples thereof include polyurethane, silicone resin, ethylene propylene rubber, styrene resin, olefin resin, polyamide, and polyester.

[0048] Figure 5The relationship between surface pressure deviation and the hardness of the soft resin S is plotted. Here, surface pressure deviation refers to the ratio of the maximum surface pressure to the minimum surface pressure when a load of 1.0 MPa is applied to the elastic member 14A, with the corrugated leaf spring W and the soft resin S arranged on both sides. The surface pressure is measured on the soft resin S side.

[0049] Depend on Figure 5 It is understood that when the hardness of the soft resin S is E40 or less or E60 or more, the variation in surface pressure is reduced.

[0050] The battery cells 11a are not particularly limited, and examples thereof include solid battery cells such as all-solid lithium metal battery cells and electrolyte battery cells such as lithium metal battery cells. Among them, solid battery cells are preferred.

[0051] Hereinafter, a case where the battery cell 11 a is an all-solid-state lithium metal battery cell will be described.

[0052] An all-solid-state lithium metal battery cell comprises, for example, a positive electrode current collector, a positive electrode composite material layer, a solid electrolyte layer, a lithium metal layer, and a negative electrode current collector stacked in this order.

[0053] The positive electrode current collector is not particularly limited, and an example thereof includes aluminum foil.

[0054] The positive electrode composite material layer contains a positive electrode active material and may further contain a solid electrolyte, a conductive additive, a binder, and the like.

[0055] The positive electrode active material is not particularly limited as long as it can absorb and release lithium ions, and examples thereof include LiCoO2, Li(Ni 5 / 10 Co 2 / 10 Mn 3 / 10 )O2、Li(Ni 6 / 10 Co 2 / 10 Mn 2 / 10 )O2、Li(Ni 8 / 10 Co 1 / 10 Mn 1 / 10 )O2、Li(Ni 0.8 Co 0.15 Al 0.05 )O2、Li(Ni 1 / 6 Co 4 / 6 Mn 1 / 6 )O2、Li(Ni 1 / 3 Co 1 / 3 Mn 1 / 3 )O2, LiCoO4, LiMn2O4, LiNiO2, LiFePO4, lithium sulfide, sulfur.

[0056] 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.

[0057] The negative electrode current collector is not particularly limited, and examples thereof include copper foil.

[0058] As mentioned above, although embodiment of this invention was demonstrated, this invention is not limited to the said embodiment, The said embodiment can also be modified suitably within the range of the summary of this invention.

[0059] Reference numerals

[0060] 10: Battery module

[0061] 11: Battery cell stack

[0062] 11a: Battery cell

[0063] 12: End plate

[0064] 13: Connecting rod

[0065] 14: Buffer material

[0066] W: corrugated leaf spring

[0067] S: Soft resin

[0068] R: concave part

[0069] C: convex part

Claims

1. A battery module comprising: A battery cell stack having a plurality of battery cells stacked thereon; a pair of plate-like members provided at both ends of the battery cell stack in the stacking direction; and a buffer material disposed between the plurality of battery cells and / or between the battery cell stack and the plate-shaped member; and The cushioning material includes a corrugated leaf spring having concave portions and convex portions alternately arranged continuously and extending in a predetermined direction. 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 buffer material.

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

3. The battery module according to claim 1 or 2, wherein: The cushioning material is formed by stacking a plurality of the corrugated leaf springs in a stacking direction of the battery cell stack, with the concave portions and the convex portions of adjacent corrugated leaf springs facing and contacting each other.

4. The battery module according to claim 1 or 2, wherein: The aforementioned battery cells are solid battery cells.

5. A method for manufacturing a battery module, comprising the steps of: A coating liquid containing the soft resin or a precursor of the soft resin is applied to the surface of the battery cell facing the buffer material.

6. The method for manufacturing a battery module according to claim 5, wherein: The precursor of the soft resin is an ultraviolet curable resin. The manufacturing method of the battery module further includes the following steps: The surface coated with the coating liquid containing the ultraviolet curable resin is irradiated with ultraviolet rays.

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