Battery module and method of manufacturing a battery module

Abstract

A battery module is provided. The battery module has: a battery cell stack in which a plurality of battery cells are stacked; a pair of plate-shaped members provided at both ends in a stacking direction of the battery cell stack; and a buffer material disposed between the plurality of battery cells and / or between the battery cell stack and the plate-shaped members, the buffer material having: a pair of first elastic members disposed at both outer sides in the stacking direction of the battery cell stack; and a second elastic member disposed between the pair of first elastic members, the second elastic member being formed by a wave-shaped plate spring stacked in the stacking direction of the battery cell stack in a plurality of layers, a plurality of contact regions in a width direction in which the second elastic member contacts the first elastic members being present, one or both of the pair of first elastic members having an extension portion extending toward the other of the pair of first elastic members outside of one or both of the width directions from the second elastic member.

Description

Technical Field

[0001] This invention relates to a battery module and a method for manufacturing the battery module. Background Technology

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

[0003] Since battery cells expand and contract during charging and discharging, battery modules, for example, have a pair of end plates and a constraint strip, wherein the pair of end plates are disposed at both ends in the stacking direction of the battery cell stack; and 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 due to the expansion of the battery during charging, the surface pressure difference between the portions of the first and second plates that contact the corrugated plate and the portions that do not contact the corrugated plate increases, resulting in a decrease in the uniformity of the surface pressure of the limiting unit. Furthermore, in the energy storage device described in Reference 1, when the limiting unit is compressed due to the expansion of the battery during charging, the end of the corrugated plate in the width direction may contact a component located on the side of the corrugated plate in the width direction, raising concerns about potential damage to the energy storage device.

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

[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 of the battery cell stack in the stacking direction; 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 of the battery cell stack in the stacking direction; the second elastic member is disposed between the pair of first elastic members, the second elastic member being formed by stacking multiple layers of wave-shaped leaf springs along the stacking direction of the battery cell stack, the second elastic member having multiple contact areas in the width direction that contact the first elastic members, one or both of the pair of first elastic members having an extension portion that extends to the other of the pair of first elastic members on the outer side of one or both of the second elastic members in the width direction.

[0012] (2) According to the battery module of (1), the wave-shaped leaf spring is arranged in a continuous manner with alternating concave and convex portions and extends in a predetermined direction, wherein in the second elastic member, the concave and convex portions of adjacent wave-shaped leaf springs are in contact with each other.

[0013] (3) According to the battery module described in (2), in the leaf spring of the waveform, the length in the width direction between the top surface of the convex portion or the bottom surface of the concave portion adjacent to the end in the width direction and the end in the width direction is greater than the length in the width direction between the bottom surface of the adjacent concave portion and the top surface of the convex portion.

[0014] (4) In any one of (1) to (3) the battery module, the pair of first elastic members and the second elastic member are fixed in the contact area in the cushioning material.

[0015] (5) In any one of (1) to (4) of the battery module, the end of the leaf spring of the waveform in the width direction is not fixed.

[0016] (6) According to any one of (1) to (5) the battery module, the leaf spring of the waveform is separated from the leaf spring of the adjacent waveform at the end in the width direction.

[0017] (7) In any one of (1) to (6) the battery module, in the cushioning material, the extension contacts the other of the pair of first elastic members.

[0018] (8) According to the battery module of (7), in the cushioning material, the extension is fixed to the other of the pair of first elastic members.

[0019] (9) According to the battery module of (7), the pair of first elastic members are integrated in the cushioning material.

[0020] (10) The battery module according to any one of (1) to (9) wherein the battery cell is a solid-state battery cell.

[0021] (11) A method of manufacturing the battery module of (4), wherein the pair of first elastic components of the buffer material are integrated, the method comprising: a coating step of coating an elastic adhesive on both sides of the second elastic component; and an insertion step of inserting the second elastic component coated with the elastic adhesive into the integrated pair of first elastic components.

[0022] (12) A method of manufacturing the battery module of (4), the method comprising: a coating step of coating an elastic adhesive on one side of the second elastic member; a placement step of placing one of the pair of first elastic members on one side of the second elastic member coated with the elastic adhesive; a coating step of coating an elastic adhesive on the other side of the second elastic member; and a placement step of placing the other of the pair of first elastic members on the other side of the second elastic member coated with the elastic adhesive.

[0023] [Invention Effects]

[0024] According to the present invention, a battery module that can improve the uniformity of surface pressure of the buffer material and suppress breakage can be provided. Attached Figure Description

[0025] Figure 1 This is a cross-sectional view of a battery module according to an embodiment of the present invention.

[0026] Figure 2 It means Figure 1 A cross-sectional view of the cushioning material.

[0027] Figure 3 yes Figure 2 A partially enlarged cross-sectional view of the cushioning material.

[0028] Figure 4 It means Figure 2 A cross-sectional view of a leaf spring with a wave pattern.

[0029] Figure 5 This is an explanation Figure 2 A cross-sectional view of the manufacturing method of the cushioning material.

[0030] Figure 6 This is an explanation Figure 2 A cross-sectional view of a modified example of the manufacturing method of the cushioning material. Detailed Implementation

[0031] Below, refer to the appendix. Figure 1 The embodiments of the present invention will be described below.

[0032] Figure 1 A battery module according to one embodiment of the present invention is shown.

[0033] 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.

[0034] 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.

[0035] 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.

[0036] like Figure 2 As shown, 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 both 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 and 14c. 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.

[0037] 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 and 14c that contacts the second elastic member 14b and the portion of the first elastic member 14a and 14c that does not contact the second elastic member 14b becomes smaller, thereby improving the uniformity of surface pressure.

[0038] Furthermore, the second elastic member 14b has multiple contact areas A in the width direction D that contact the first elastic members 14a and 14c. At this time, the first elastic member 14a has an extension E on its outer side in the width direction D, which is closer to the second elastic member 14b. This extension E extends towards the first elastic member 14c and contacts the first elastic member 14c (see reference). Figure 3 Furthermore, the first elastic member 14c has an extension on its outer side, on the opposite side of the second elastic member 14b in the width direction D. This extension extends toward and contacts the first elastic member 14a. Therefore, when the cushioning material 14 is compressed as the battery cell 11a expands during charging, it can prevent the second elastic member 14b from contacting the component located on its side in the width direction D. As a result, it can prevent damage to the battery module 10.

[0039] Alternatively, in the cushioning material 14, the first elastic member 14a may have an extension, while the first elastic member 14c may not have an extension. In this case, the first elastic member 14a may have an extension on both sides of the second elastic member 14b in the width direction D, and this extension extends toward the first elastic member 14c.

[0040] Alternatively, in the cushioning material 14, the extension may not contact the first elastic member 14c (or 14a).

[0041] like Figure 4 As shown, the wave-shaped leaf spring W constituting the second elastic member 14b is arranged with alternating concave portions R and convex portions C, and extends along the depth direction in the figure. At this time, the concave portions R and convex portions C of adjacent wave-shaped leaf springs W are in contact with each other. Furthermore, the concave portions R and convex portions C protrude downwards and upwards respectively in the stacking direction of the battery cell stack 11. At this time, in the wave-shaped leaf spring W, the length L1 in the width direction D between the top surface of the convex portion C (or the bottom surface of the concave portion R) adjacent to the end in the width direction D and the end in the width direction D is greater than the length L2 in the width direction D between the bottom surface of the adjacent concave portion R and the top surface of the convex portion C. Therefore, the hysteresis loss of the second elastic member 14b can be reduced. At this time, the ratio of L1 to L2 is not particularly limited, for example, it is 1 or more and 2 or less. In addition, L1 is not particularly limited, for example, it is 5 mm or more and 20 mm or less.

[0042] In the cushioning material 14, the first elastic members 14a and 14c and the second elastic member 14b are fixed in the contact area A. Therefore, the strength of the cushioning material 14 is improved. There is no particular limitation on the method for fixing the first elastic members 14a and 14c and the second elastic member 14b in the contact area A; for example, a method of bonding the first elastic members 14a and 14c and the second elastic member 14b together in the contact area A using an elastic adhesive can be cited.

[0043] In the cushioning material 14, the extension E of the first elastic member 14a is fixed to the first elastic member 14c, and the extension of the first elastic member 14c is fixed to the first elastic member 14a. Therefore, the strength of the cushioning material 14 is improved. There is no particular limitation on the method for fixing the extension to the first elastic member; for example, a method of bonding the extension to the first elastic member using an elastic adhesive can be cited.

[0044] Alternatively, the first elastic members 14a and 14c may be integrated into the cushioning material 14. That is, the cushioning material 14 may have elastic members that have a shape formed by integrating the first elastic members 14a and 14c.

[0045] On the other hand, the end of the wave-shaped leaf spring W in the width direction D is not fixed. Furthermore, the end of the wave-shaped leaf spring W in the width direction D is separated from the adjacent wave-shaped leaf spring W. Therefore, the hysteresis loss of the second elastic member 14b can be reduced. At this time, the interval between the ends of adjacent wave-shaped leaf springs W in the width direction D is not particularly limited, for example, it is 0.1 mm or more and 1 mm or less.

[0046] Furthermore, the number of layers of the wave-shaped leaf spring W is not limited to two; it can be two or more. There is no particular limitation on the number of layers of the wave-shaped leaf spring W, for example, it can be two or more layers but less than six layers. When the number of layers of the wave-shaped leaf spring W is three or more, the shape of the wave-shaped leaf spring W that does not make contact in contact area A is not particularly limited; for example, it can be the same as the wave-shaped leaf spring W that makes contact in contact area A.

[0047] Alternatively, in adjacent leaf springs W, portions of the concave portion R and the convex portion C that are in contact with each other can be bonded together, for example, by an elastic adhesive.

[0048] The Poisson's ratio of the first elastic components 14a and 14c is preferably 0.3 or less. When the Poisson's ratio of the first elastic components 14a and 14c is 0.3 or less, the first elastic components 14a and 14c can easily absorb the thickness changes caused by the expansion and contraction of the battery cell 11a. In addition, the Poisson's ratio of the first elastic components 14a and 14c is, for example, 0 or more.

[0049] The thickness of the first elastic members 14a and 14c 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.

[0050] The first elastic components 14a and 14c are, for example, foams 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.

[0051] 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.

[0052] 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.

[0053] 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 more than 1.0 mm and less than 1.2 mm.

[0054] The following describes an example of the manufacturing method of the cushioning material 14. First, a first elastic member 14a is obtained by foam molding. On the other hand, after a corrugated leaf spring W is formed by stamping, a portion of the two-layer corrugated leaf spring W is bonded together with an elastic adhesive to obtain a second elastic member 14b. Next, an elastic adhesive G is applied to the bottom surface of the recess R on the lower side of the second elastic member 14b, and then the first elastic member 14c (see reference) is placed on it. Figure 5 (a)). At this time, pressure can be applied while the first elastic member 14c is placed on the bottom surface of the recess R below the second elastic member 14b, or pressure can be applied after the first elastic member 14c is placed on the bottom surface of the recess R below the second elastic member 14b. Next, elastic adhesive G is applied to the top surface of the protrusion C on the upper side of the second elastic member 14b and the end faces of the extensions of the first elastic members 14a and 14c, and then the first elastic member 14a (see reference) is placed on the second elastic member 14b. Figure 5(b)). At this time, pressure can be applied while the first elastic member 14a is placed on the top surface of the protrusion C on the upper side of the second elastic member 14b, or pressure can be applied after the first elastic member 14a is placed on the top surface of the protrusion C on the upper side of the second elastic member 14b.

[0055] Next, a modified example of the manufacturing method of the cushioning material 14 will be described. First, a first elastic member 14d is obtained by foam molding. Here, the first elastic member 14d is a component integrally formed from the first elastic members 14a and 14c. On the other hand, after the corrugated leaf spring W is formed by stamping, a portion of the two-layer corrugated leaf spring W is bonded together with an elastic adhesive to obtain a second elastic member 14b. Next, an elastic adhesive G is applied to the top surface of the protrusion C on the upper side and the bottom surface of the concave R on the lower side of the second elastic member 14b, and then it is inserted into the first elastic member 14d (see reference). Figure 6 At this time, the second elastic member 14b is positioned by the first elastic member 14d, so it is not easy for its position to shift, which improves the assemblability of the cushioning material 14. At this time, pressure can be applied at the same time as the second elastic member 14b is inserted into the first elastic member 14d, or pressure can be applied after the second elastic member 14b is inserted into the first elastic member 14d.

[0056] The buffer material 14 manufactured in the above manner has high strength, thus improving the portability of the buffer material 14, which in turn improves the assemblability of the battery module 10.

[0057] As a method for manufacturing the battery module 10 using the cushioning material 14, a known method can be used.

[0058] 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.

[0059] The following explanation addresses the case where battery cell 11a is an all-solid-state lithium metal battery cell.

[0060] 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.

[0061] There are no particular limitations on what can be used as a positive current collector; for example, aluminum foil can be listed.

[0062] The positive electrode mixture layer contains positive electrode active material and may further contain solid electrolyte, conductive additives, binders, etc.

[0063] 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.

[0064] 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.

[0065] There are no particular limitations on what can be used as a negative current collector; for example, copper foil can be used.

[0066] The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and appropriate changes can be made to the above embodiments without departing from the spirit of the present invention.

[0067] [Explanation of reference numerals in the attached figures]

[0068] 10: Battery module; 11: Battery cell stack; 11a: Battery cell; 12: End plate; 13: Constraint strip; 14: Buffer material; 14a, 14c, 14d: First elastic component; 14b: Second elastic component; A: Contact area; E: Extension; W: Wave-shaped leaf spring; R: Recess; C: Protrusion; G: Elastic adhesive.

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 component is formed by stacking multiple layers of wave-shaped leaf springs along the stacking direction of the battery cell laminate. The second elastic component has multiple contact areas in the width direction that contact the first elastic component. One or both of the pair of first elastic members have an extension that extends outward from the other of the pair of first elastic members in the width direction than the second elastic member.

2. The battery module according to claim 1, characterized in that, The wave-shaped leaf spring is arranged with alternating concave and convex portions and extends in a predetermined direction. In the second elastic member, the concave and convex portions of adjacent wave-shaped leaf springs are in contact with each other.

3. The battery module according to claim 2, characterized in that, In the wave-shaped leaf spring, the length in the width direction between the top surface of the convex portion or the bottom surface of the concave portion adjacent to the end in the width direction and the end in the width direction is greater than the length in the width direction between the bottom surface of the adjacent concave portion and the top surface of the convex portion.

4. The battery module according to any one of claims 1 to 3, characterized in that, In the cushioning material, the pair of first elastic members and the second elastic member are fixed in the contact area.

5. The battery module according to any one of claims 1 to 3, characterized in that, The ends of the leaf spring in the width direction of the waveform are not fixed.

6. The battery module according to any one of claims 1 to 3, characterized in that, The leaf spring of the waveform separates from the adjacent leaf spring of the waveform at the end in the width direction.

7. The battery module according to any one of claims 1 to 3, characterized in that, In the cushioning material, the extension contacts the other of the pair of first elastic members.

8. The battery module according to claim 7, characterized in that, In the cushioning material, the extension is fixed to the other of the pair of first elastic members.

9. The battery module according to claim 7, characterized in that, In the cushioning material, the pair of first elastic components are integrated.

10. The battery module according to any one of claims 1 to 3, characterized in that, The battery cell is a solid-state battery cell.

11. A method for manufacturing a battery module, used to manufacture the battery module of claim 4, characterized in that, The pair of first elastic components of the cushioning material are integrated. The method includes: a coating step, wherein an elastic adhesive is applied to both surfaces of the second elastic member; and In the insertion process, the second elastic component coated with the elastic adhesive is inserted into the integrated pair of first elastic components.

12. A method for manufacturing a battery module, used to manufacture the battery module of claim 4. Its features are, Includes: a coating process, in which an elastic adhesive is applied to one surface of the second elastic component; In the placement process, one of the pair of first elastic members is placed on a surface of the second elastic member coated with the elastic adhesive. In the coating process, an elastic adhesive is applied to the other side of the second elastic component; In the placement process, one of the pair of first elastic components is placed on the other side of the second elastic component that is coated with the elastic adhesive.

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