Battery module

Abstract

A battery module is provided. The battery module has: a battery cell laminate in which a plurality of battery cells are laminated; a pair of plate-shaped members provided at both ends in a lamination direction of the battery cell laminate; and a buffer material disposed between the plurality of battery cells and / or between the battery cell laminate and the plate-shaped members, the buffer material having: a pair of first elastic members disposed at both outer sides in the lamination direction of the battery cell laminate; and a second elastic member disposed between the pair of first elastic members, the second elastic member having a wave-shaped plate spring in which recesses and protrusions are alternately and continuously arranged and extend in a prescribed direction, and a surface of the first elastic member on a side facing the second elastic member being shaped in a wave in which recesses and protrusions are alternately and continuously arranged and extend in the prescribed direction.

Description

Technical Field

[0001] This invention relates to a battery module. Background Technology

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable and advanced energy, technological development is underway to improve the energy efficiency of battery modules.

[0003] A battery module may have, for example, a battery cell stack composed of multiple battery cells. Here, since the battery cells expand and contract during charging and discharging, the battery module may have, for example, a pair of end plates and a constraint strip, wherein the pair of end plates are disposed at both ends of the battery cell stack in the stacking direction; the constraint strip is used to constrain the battery cell stack between the pair of end plates.

[0004] Patent Document 1 describes an energy storage device comprising an energy storage module, a housing, and a limiting unit. The energy storage module includes a plurality of batteries stacked along a stacking direction; the housing houses the energy storage module; and the limiting unit is disposed between the batteries. Here, the limiting unit includes a first plate and a second plate spaced apart along the stacking direction, and a corrugated plate disposed between the first plate and the second plate.

[0005] [Existing Technical Documents] [Patent Literature]

[0006] Patent Document 1: Japanese Patent Publication No. 2022-156427 Summary of the Invention

[0007] [The technical problem that the invention aims to solve]

[0008] However, in the energy storage device described in Reference 1, when the limiting unit is compressed as the battery expands during charging, the surface pressure difference between the parts of the first and second plates that are in contact with the corrugated plate and the parts of the first and second plates that are not in contact with the corrugated plate increases, thereby reducing the uniformity of the surface pressure of the limiting unit.

[0009] The purpose of this invention is to provide a battery module that can improve the uniformity of surface pressure of the buffer material.

[0010] [Technical solutions used to solve technical problems]

[0011] (1) A battery module having a battery cell stack, a pair of plate-shaped members and a buffer material, wherein the battery cell stack is formed by stacking multiple battery cells; the pair of plate-shaped members are disposed at both ends in the stacking direction of the battery cell stack; the buffer material is disposed between the multiple battery cells and / or between the battery cell stack and the plate-shaped members, the buffer material having a pair of first elastic members and a pair of second elastic members, wherein the pair of first elastic members are disposed on both outer sides in the stacking direction of the battery cell stack; the second elastic member is disposed between the pair of first elastic members, the second elastic member having a wave-shaped leaf spring, the wave-shaped leaf spring being arranged in an alternating continuous manner of concave and convex portions and extending in a predetermined direction, the shape of the surface of the first elastic member facing the second elastic member being a wave-shaped arrangement of concave and convex portions arranged in an alternating continuous manner and extending in the predetermined direction.

[0012] (2) According to the battery module described in (1), the recess and protrusion of the first elastic member disposed on the recess side of the wave-shaped leaf spring face the recess and protrusion of the wave-shaped leaf spring, and the recess and protrusion of the first elastic member disposed on the protrusion side of the wave-shaped leaf spring face the protrusion and recess of the wave-shaped leaf spring.

[0013] (3) According to the battery module described in (1) or (2), the second elastic member is formed by stacking multiple layers of the waveform leaf spring in the stacking direction of the battery cell stack, and the concave and convex portions of adjacent waveform leaf springs are in contact with each other.

[0014] (4) The battery module according to any one of (1) to (3), wherein the battery cell is a solid-state battery cell.

[0015] [Invention Effects]

[0016] According to the present invention, a battery module capable of improving the uniformity of surface pressure of the buffer material can be provided. Attached Figure Description

[0017] Figure 1 This is a cross-sectional view of a battery module according to an embodiment of the present invention.

[0018] Figure 2 It means Figure 1 A diagram of the buffer material in the middle.

[0019] Figure 3 yes Figure 2 A partial enlarged view of the first elastic component.

[0020] Figure 4 yes Figure 2A magnified view of the second elastic component.

[0021] Figure 5 It means Figure 2 A graph showing the relationship between the surface pressure distribution and the thickness difference between the protrusions and concave parts of the first elastic member.

[0022] Figure 6 It means Figure 2 A cross-sectional view of a deformed example of the cushioning material.

[0023] Figure 7 It means Figure 2 A cross-sectional view of a deformed example of the cushioning material.

[0024] Figure 8 It means Figure 2 A cross-sectional view of a deformed example of the cushioning material. Detailed Implementation

[0025] Below, refer to the appendix. Figure 1 The embodiments of the present invention will be described below.

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

[0027] The battery module 10 has a battery cell stack 11, end plates 12, and constraint strips 13. The battery cell stack 11 is formed by stacking multiple battery cells 11a. The end plates 12 are a pair of plate-shaped components disposed at both ends of the battery cell stack 11 in the stacking direction. The constraint strips 13 are constraint components used to constrain the battery cell stack 11 between the pair of end plates 12. Here, the constraint strips 13 are disposed at both the upper and lower parts in the figure.

[0028] In the battery module 10, a buffer material 14 is disposed between multiple battery cells 11a and between the battery cell stack 11 and the end plate 12.

[0029] Alternatively, the buffer material 14 can be disposed between multiple battery cells 11a, or between the battery cell stack 11 and the end plate 12.

[0030] Figure 2 The cushioning material 14 is shown. Furthermore, Figure 2 (a) and (b) in the figure are, respectively, a three-dimensional view and a cross-sectional view of the battery cell stack 11 in the stacking direction.

[0031] The buffer material 14 has a pair of first elastic members 14a and a second elastic member 14b, wherein the pair of first elastic members 14a are disposed on the two outer sides of the battery cell laminate 11 in the stacking direction; and the second elastic member 14b is disposed between the pair of first elastic members 14a. Furthermore, the second elastic member 14b is formed by stacking two layers of wave-shaped leaf springs W along the stacking direction of the battery cell laminate 11. Therefore, the hysteresis loss of the buffer material 14 can be reduced.

[0032] Here, when the buffer material 14 is compressed as the battery cell 11a expands during charging, the surface pressure difference between the portion of the first elastic member 14a that contacts the second elastic member 14b and the portion of the first elastic member 14a that does not contact the second elastic member 14b becomes smaller, thereby improving the uniformity of the surface pressure.

[0033] like Figure 3 As shown, the surface of the first elastic member 14a facing the second elastic member 14b has a concave portion R1 and a convex portion C1 arranged in an alternating and continuous manner, and is a waveform extending in the longitudinal direction in the figure.

[0034] like Figure 4 As shown, the wave-shaped leaf springs W constituting the second elastic member 14b are arranged in a continuous alternating manner with concave portions R2 and convex portions C2, and extend along the depth direction in the figure. In addition, in the second elastic member 14b, the concave portions R2 and convex portions C2 of adjacent wave-shaped leaf springs W are in contact with each other.

[0035] Here, the recess R2 and protrusion C2 of the second elastic member 14b protrude downward and upward respectively relative to the stacking direction of the battery cell stack 11 (see reference). Figure 2 At this time, the recessed portion R1 and the protruding portion C1 of the first elastic member 14a, located on the recessed portion R2 side of the leaf spring W constituting the waveform of the second elastic member 14b (i.e., the lower side in the figure), face the recessed portion R2 and the protruding portion C2 of the leaf spring W constituting the waveform of the second elastic member 14b. Furthermore, the recessed portion R1 and the protruding portion C1 of the first elastic member 14a, located on the protruding portion C2 side of the leaf spring W constituting the waveform of the second elastic member 14b (i.e., the upper side in the figure), face the protruding portion C2 and the recessed portion R2 of the leaf spring W constituting the waveform of the second elastic member 14b, respectively.

[0036] The shapes of the recess R1 and protrusion C1 of the first elastic member 14a correspond to the shapes of the protrusion C2 and recess R2 of the second elastic member 14b, respectively. That is, approximately the entire area of ​​the recess R1 and protrusion C1 of the first elastic member 14a is in contact with approximately the entire area of ​​the protrusion C2 and recess R2 of the second elastic member 14b, respectively. Therefore, even if the thickness of the recess R1 of the first elastic member 14a is small, the uniformity of surface pressure can be improved, resulting in improved energy density and mounting capability of the battery module 10.

[0037] Figure 5 The relationship between surface pressure distribution and the thickness difference between the protrusion C1 and the recess R1 of the first elastic member 14a is shown. Here, the thickness of the recess R1 of the first elastic member 14a is set to 0.7 mm, and the surface pressure distribution when the thickness difference between the protrusion C1 and the recess R1 of the first elastic member 14a is 0, i.e., a flat first elastic member, is set to 100%. Furthermore, surface pressure distribution refers to the ratio of the difference between the maximum and minimum surface pressure values ​​to the average surface pressure when a load of 1.0 MPa is applied to the first elastic member 14a. The first elastic member 14a (refer to...) was measured... Figure 3 ) Surface pressure on the side in contact with battery cell 11a.

[0038] from Figure 5 It can be seen that even if the thickness of the recess R1 of the first elastic member 14a is small, the surface pressure distribution will be smaller due to the presence of the protrusion C1.

[0039] There is no particular limitation on the method for fixing the second elastic member 14b to the first elastic member 14a. For example, the method of bonding the second elastic member 14b to the first elastic member 14a with an elastic adhesive and the method of molding the first elastic member 14a with the second elastic member 14b disposed inside the mold can be listed.

[0040] Furthermore, the number of layers of the wave-shaped leaf spring W is not limited to 2 layers, but is preferably 2 or more layers and 6 or less layers, and more preferably 2 or more layers and 4 or less layers.

[0041] Additionally, in adjacent leaf springs W, portions of the opposing recesses R2 and convexities C2 can also be bonded together, for example, with an elastic adhesive.

[0042] Furthermore, it is also possible that, as long as the recess R1 of the first elastic member 14a faces the protrusion C2 of the second elastic member 14b, and the protrusion C1 of the first elastic member 14a faces the recess R2 of the second elastic member 14b, the shapes of the recess R1 and protrusion C1 of the first elastic member 14a do not need to correspond to the shapes of the protrusion C2 and recess R2 of the second elastic member 14b, respectively. For example, a portion of the recess R1 and protrusion C1 of the first elastic member 14a can respectively connect with a portion of the protrusion C2 and recess R2 of the second elastic member 14b, thereby forming a gap (see reference). Figure 6 ).

[0043] Alternatively, a wave-shaped leaf spring W can also be used as the second elastic component 14b (see reference). Figure 7 ).

[0044] Furthermore, it is also possible that the thickness of the protrusion C1 on the inner side of the width direction D of the concave portion R1 at both ends of the first elastic member 14a is approximately constant (refer to...). Figure 8 That is, the shape of the concave portion R1 at both ends of the first elastic member 14a and the convex portion C1 on the inner side of the width direction D can be wave-shaped, and the wave-shaped portion corresponds to the shape of the leaf spring W that is connected to the first elastic member 14a.

[0045] The Poisson's ratio of the first elastic member 14a is preferably 0.3 or less. When the Poisson's ratio of the first elastic member 14a is 0.3 or less, the first elastic member 14a easily absorbs the thickness changes caused by the expansion and contraction of the battery cell 11a. Furthermore, the Poisson's ratio of the first elastic member 14a is, for example, 0 or more.

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

[0047] The first elastic component 14a is, for example, a foam with a porosity of 30% or more and 95% or less. There are no particular limitations on the materials constituting the foam; examples include polyurethane, silicone resin, ethylene propylene rubber, styrene resin, polyolefin resin, polyamide, and polyester.

[0048] The Young's modulus of the second elastic member 14b is preferably 35 GPa or higher. When the Young's modulus of the second elastic member 14b is 35 GPa or higher, the second elastic member 14b can easily absorb the thickness changes caused by the expansion and contraction of the battery cell 11a. In addition, the Young's modulus of the second elastic member 14b is, for example, 200 GPa or lower.

[0049] The material used to form the second elastic component 14b is not particularly limited, and 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). Among these, considering the energy density of the battery module 10, FRP is preferred.

[0050] The thickness of the second elastic member 14b when the charge rate of the battery cell 11a is 100% is not particularly limited, for example, it is 1.2 mm or less.

[0051] There are no particular limitations on the battery cell 11a; for example, solid-state battery cells such as all-solid-state lithium metal battery cells and electrolyte battery cells such as lithium metal battery cells can be included. Among them, solid-state battery cells are preferred.

[0052] The following explanation addresses the case where battery cell 11a is an all-solid-state lithium metal battery cell.

[0053] A solid-state lithium metal battery cell may consist of, for example, a positive current collector, a positive electrolyte layer, a solid electrolyte layer, a lithium metal layer, and a negative current collector stacked sequentially.

[0054] There are no particular limitations on what can be used as a positive current collector; for example, aluminum foil can be listed.

[0055] The positive electrode mixture layer contains positive electrode active material and may further contain solid electrolyte, conductive additives, binders, etc.

[0056] As a positive electrode active material, it is only necessary to be able to insert and extract lithium ions; there are no particular limitations. Examples include LiCoO2 and Li(Ni)2. 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.

[0057] As a solid electrolyte that constitutes the solid electrolyte layer, any material that can conduct lithium ions is acceptable, and there are no particular limitations. Examples include oxide-based electrolytes and sulfide-based electrolytes.

[0058] There are no particular limitations on what can be used as a negative current collector; for example, copper foil can be used.

[0059] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and appropriate modifications can be made to the above embodiments within the scope of the spirit of the present invention.

[0060] [Explanation of reference numerals in the attached figures]

[0061] 10: Battery module; 11: Battery cell stack; 11a: Battery cell; 12: End plate; 13: Constraint strip; 14: Buffer material; 14a: First elastic component; 14b: Second elastic component; W: Wave-shaped leaf spring; R1, R2: Recessed portion; C1, C2: Protruding portion.

Claims

1. A battery module, characterized in that, It has a battery cell stack, a pair of plate-shaped components, and a cushioning material, wherein, The battery cell stack is composed of multiple battery cells stacked together. The pair of plate-shaped components are disposed at both ends in the stacking direction of the battery cell stack; The cushioning material is disposed between the plurality of battery cells and / or between the battery cell stack and the plate-shaped component. The cushioning material has a pair of first elastic members and a pair of second elastic members, wherein the pair of first elastic members are disposed on both outer sides in the stacking direction of the battery cell stack; and the second elastic member is disposed between the pair of first elastic members. The second elastic member has a wave-shaped leaf spring, which is arranged with alternating concave and convex portions and extends in a predetermined direction. The surface of the first elastic member facing the second elastic member has a waveform with concave and convex portions arranged in an alternating and continuous manner and extending along the specified direction.

2. The battery module according to claim 1, characterized in that, The recess and protrusion of the first elastic member, disposed on the recess side of the leaf spring of the waveform, face the recess and protrusion of the leaf spring of the waveform. The recess and protrusion of the first elastic member disposed on the convex side of the leaf spring of the waveform face the protrusion and recess of the leaf spring of the waveform.

3. The battery module according to claim 1 or 2, characterized in that, The second elastic component is formed by stacking multiple layers of the waveform leaf springs in the stacking direction of the battery cell stack, and the concave and convex portions of adjacent waveform leaf springs are in contact with each other.

4. The battery module according to claim 1 or 2, characterized in that, The battery cell is a solid-state battery cell.

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