Method for manufacturing battery module

Abstract

Provided is a method for manufacturing a battery module 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, in the buffer material, a second elastic member is disposed inside a first elastic member having a frame-shaped member disposed on the outer periphery thereof, and third elastic members are disposed on both sides of the second elastic member in the stacking direction of the battery cell stack. A second elastic member in which a corrugated plate spring is laminated in the lamination direction of the battery cell laminate, the method for manufacturing the battery module comprising the steps of: forming the second elastic member by laminating a corrugated plate spring inside the first elastic member; and forming the third elastic member by foam molding a resin inside the first elastic member on which the second elastic member is formed. Furthermore, when the third elastic component is formed, the end part of the second elastic component in the length direction is in contact with the frame-shaped component.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a battery module. Background Art

[0002] In recent years, research and development of secondary batteries that contribute to improving energy efficiency have been conducted in order to ensure that the majority of people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Since battery cells expand and contract during charge and discharge, 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 binding bars that constrain the battery cell stack between the pair of 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 Citation 1, as the power storage cells expand during charging, the restriction unit is compressed. This increases the difference in surface pressure between the portions of the first and second flat plates that contact the corrugated plate and the portions that do not, reducing the uniformity of the surface pressure within the restriction unit. Furthermore, in the power storage device described in Citation 1, the placement of the corrugated plate between the first and second flat plates easily causes positional displacement, resulting in poor assembly of the restriction unit.

[0010] An object of the present invention is to provide a method for manufacturing a battery module, which can improve the uniformity of the surface pressure of a buffer material and the assembly performance.

[0011] [Technical means to solve the problem]

[0012] (1) A method for manufacturing a battery module, the battery module comprising: a battery cell stack having a plurality of battery cells stacked thereon; a pair of plate-like components provided at both ends of the battery cell stack in a stacking direction; and a buffer material arranged between the plurality of battery cells and / or between the battery cell stack and the plate-like components; and, in the buffer material, a second elastic component is arranged inside a first elastic component having a frame-like component arranged at an outer periphery, and a third elastic component is arranged on both sides of the second elastic component in the stacking direction of the battery cell stack, the second elastic component having a corrugated leaf spring stacked in the stacking direction of the battery cell stack, the method for manufacturing the battery module comprising the following steps: forming the second elastic component by stacking a corrugated leaf spring inside the first elastic component; and forming the third elastic component by foaming a resin inside the first elastic component having the second elastic component formed thereon; and, when forming the third elastic component, an end portion of the second elastic component in a longitudinal direction contacts the frame-like component.

[0013] (2) A method for manufacturing a battery module according to (1), wherein the second elastic component is formed in a manner such that a plurality of contact areas exist in the width direction, the contact area being a contact area where the second elastic component contacts the bottom surface of the first elastic component, and the wavy leaf spring in contact with the contact area has an extension portion, the extension portion extending from the outermost contact area in the width direction toward the outer side in the width direction, and the greater the distance of the extension portion from the outermost contact area in the width direction, the greater the distance in the thickness direction from the bottom surface of the first elastic component.

[0014] (3) The method for manufacturing a battery module according to (1) or (2), wherein the cross-sectional shape of the bottom surface of the first elastic member is a wavy shape corresponding to the cross-sectional shape of a wavy leaf spring contacting the bottom surface of the first elastic member.

[0015] (4) The method for manufacturing a battery module according to any one of (1) to (3), wherein the frame-shaped member has a groove-shaped portion formed in a region facing an end portion in the width direction of the second elastic member.

[0016] (5) The method for manufacturing a battery module according to (4), wherein the shapes of both side surfaces of the groove-shaped portion correspond to the widthwise end portions of the second elastic member.

[0017] (6) The method for manufacturing a battery module according to any one of (1) to (5), wherein the battery cell is a solid battery cell.

[0018] (Effects of the Invention)

[0019] According to the present invention, a method for manufacturing a battery module can be provided, which can improve the uniformity of the surface pressure of a buffer material and the assembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 FIG1 is a cross-sectional view showing a battery module according to one embodiment of the present invention.

[0021] Figure 2 It is a drawing Figure 1 Cross-sectional view of the cushioning material.

[0022] Figure 3 It is an explanation Figure 2 A cross-sectional view of a method for manufacturing a cushioning material.

[0023] Figure 4 yes Figure 3 A partially enlarged cross-sectional view of the first elastic component and the second elastic component.

[0024] Figure 5 It is a drawing Figure 3 Cross-section of a corrugated leaf spring.

[0025] Figure 6 It is a drawing Figure 3 sectional view of a modified example of the first elastic component.

[0026] Figure 7 It is a drawing Figure 3 A partially enlarged cross-sectional view of a modified example of the first elastic component.

[0027] Figure 8 It is a drawing Figure 7 A partially enlarged cross-sectional view of a modified example of the first elastic component. DETAILED DESCRIPTION

[0028] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0029] Figure 1 A battery module according to one embodiment of the present invention is shown.

[0030] [Battery module]

[0031] 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 binding rods 13 serving as restraining members for restraining the battery cell stack 11 between the pair of end plates 12. The binding rods 13 are disposed at both the upper and lower portions of the battery cell stack in the figure.

[0032] 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 .

[0033] 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 .

[0034] like Figure 2 As shown, the cushioning material 14 comprises a second elastic member 14b disposed within a first elastic member 14a having a frame-shaped member F disposed on its outer periphery. Third elastic members 14c are disposed on both sides of the second elastic member 14b in the stacking direction of the battery cell stack 11. Furthermore, the second elastic member 14b comprises two layers of corrugated leaf springs W stacked in the stacking direction of the battery cell stack 11. This reduces hysteresis loss in the cushioning material 14.

[0035] Here, when the buffer material 14 is compressed as the battery cell 11 a expands during charge, the third elastic member 14 c (and 14 a ) is interposed between the battery cell 11 a and the second elastic member 14 b , thereby improving the uniformity of the surface pressure.

[0036] Furthermore, the first elastic member 14a is provided with a frame-shaped member F on its outer periphery. Therefore, when the buffer material 14 is compressed as the battery cells 11a expand during charging, contact with components located to the sides of the second elastic member 14b in the width direction D1 is suppressed, thereby preventing damage to the battery module 10.

[0037] The number of stacked corrugated leaf springs W is not limited to 2, and may be 2 or more. The number of stacked corrugated leaf springs W is not particularly limited, and is, for example, 2 or more and 6 or less.

[0038] The Poisson's ratio of the first elastic member 14a and the third elastic member 14c is preferably 0.3 or less. When the Poisson's ratio of the first elastic member 14a and the third elastic member 14c is 0.3 or less, the first elastic member 14a and the third elastic member 14c can easily absorb 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 and the third elastic member 14c can be, for example, 0 or greater.

[0039] The thickness of the first elastic member 14a when the charge rate of the battery cell 11a is 100% is not particularly limited, and is, for example, 0.05 mm to 0.1 mm.

[0040] The first elastic member 14a and the third elastic member 14c are, for example, foams 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.

[0041] Furthermore, the materials constituting the first elastic member 14 a and the third elastic member 14 c may be the same or different.

[0042] The Young's modulus of the second elastic member 14b is preferably 35 GPa or greater. When the Young's modulus of the second elastic member 14b is 35 GPa or greater, the second elastic member 14b can easily absorb the thickness changes caused by the expansion and contraction of the battery cell 11a. Alternatively, the Young's modulus of the second elastic member 14b is, for example, 200 GPa or less.

[0043] The material constituting the second elastic member 14b is not particularly limited, and 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 preferred in consideration of the energy density of the battery module 10.

[0044] The thickness of the second elastic member 14 b when the charge rate of the battery cell 11 a is 100% is not particularly limited, and is, for example, 1.0 mm to 1.2 mm.

[0045] [Method for manufacturing a battery module]

[0046] Next, a method for manufacturing the cushioning material 14 will be described. First, a second elastic member 14b is formed by laminating a corrugated leaf spring W inside a first elastic member 14a having a frame-shaped member F disposed on its outer periphery (see FIG. Figure 3 At this time, since the second elastic member 14b is positioned by the frame member F, it is less likely to be misaligned, and as a result, the assemblability of the cushioning material 14 is improved. Next, the third elastic member 14c is formed by foaming the resin inside the first elastic member 14a on which the second elastic member 14b is formed (see Figure 2 At this point, both ends of the second elastic member 14b in the longitudinal direction (in the figure, the front and depth directions) are in contact with the frame member F. Therefore, when the resin for foam molding is injected into the interior of the first elastic member 14a, the resin is prevented from spreading into the interior of the second elastic member 14b. At this point, for example, the second elastic member 14b is lightly pressed against the frame member F.

[0047] Furthermore, if the resin is foam-molded inside the mold in which the second elastic member 14b is disposed without using the first elastic member 14a, when the resin for foam molding is injected into the mold, the resin may spread from both ends of the second elastic member 14b in the longitudinal direction into the interior of the second elastic member 14b.

[0048] Here, the second elastic member 14b is formed so as to have a plurality of contact areas A in the width direction D1. The contact areas A are contact areas where the second elastic member 14b contacts the bottom surface of the first elastic member 14a. The corrugated leaf spring W in contact at the contact areas A has an extension E extending outward in the width direction D1 from the outermost contact areas A on both sides in the width direction D1 (see FIG. Figure 4 In this case, the greater the distance of the extension E from the outermost contact area A in the width direction D1, the greater the distance from the bottom surface of the first elastic member 14a in the thickness direction D2. Therefore, when the resin used for foam molding is injected into the interior of the first elastic member 14a, the resin is prevented from spreading into the interior of the second elastic member 14b. In this case, the wavy leaf spring W not in contact with the contact area A has an extension corresponding to the extension E of the wavy leaf spring W in contact with the contact area A.

[0049] Furthermore, the corrugated leaf spring W in contact at the contact region A may include an extension E extending from the outermost contact region A located on one side in the width direction D1 toward the outside in the width direction D1 .

[0050] like Figure 5 As shown, the corrugated leaf spring W constituting the second elastic member 14b is alternately and continuously arranged with recesses R and protrusions C, extending in the depth direction in 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 thickness direction D2. The length L1 in the width direction D between the top surface of a protrusion C (or the bottom surface of a recess R) adjacent to an end portion of the corrugated leaf spring W in the width direction D1 and the end portion in the width direction D is greater than the length L2 in the width direction D between the bottom surface of the adjacent recess R and the top surface of the protrusion C. Therefore, when the resin used for foam molding is injected into the interior of the first elastic member 14a, the resin is prevented from spreading into the interior of the second elastic member 14b. The ratio of L1 to L2 is not particularly limited and is, for example, between 1 and 2. L1 is also not particularly limited and is, for example, between 5 mm and 20 mm.

[0051] Furthermore, the cross-sectional shape of the bottom surface of the first elastic member 14a may also be a wave shape corresponding to the cross-sectional shape of the convex portion C and the concave portion R of the wave-shaped leaf spring W contacting the bottom surface of the first elastic member 14a (see FIG. Figure 6 That is, substantially the entire bottom surface of the first elastic member 14a can also be in contact with substantially the entire convex portion C and concave portion R of the corrugated leaf spring W that are in contact with the bottom surface of the first elastic member 14a. In this case, since the second elastic member 14b is positioned by the bottom surface of the first elastic member 14a, it is less likely to be misaligned, resulting in improved assemblability of the cushioning material 14.

[0052] Alternatively, the frame-shaped member F may include a groove-shaped portion G in a region facing the end of the second elastic member 14b in the width direction D1. In this case, the second elastic member 14b is positioned by the groove-shaped portion G, making it less likely to shift, thereby improving the assembly efficiency of the cushioning material 14. Furthermore, when the second elastic member 14b is lightly pressed into the frame-shaped member F, the second elastic member 14b is less likely to deflect, resulting in improved dimensional accuracy of the third elastic member 14c. The depth of the groove-shaped portion G, i.e., its length in the width direction D1, is not particularly limited and may be, for example, 0.5 mm to 2 mm.

[0053] Here, the groove portion G preferably has both side surfaces formed into curved surfaces corresponding to the ends of the second elastic member 14b in the width direction D1 (see FIG. Figure 8 ). This improves the sealing performance of the cushioning material 14. The shapes of the two side surfaces of the groove portion G are not limited to curved surfaces, and may be inclined surfaces, for example, as long as the two side surfaces correspond to the ends of the second elastic member 14b in the width direction D1.

[0054] Furthermore, when the corrugated leaf springs W are stacked inside the first elastic member 14 a , portions of the concave portions R and convex portions C of adjacent corrugated leaf springs W that are in contact with each other may be bonded together using, for example, an elastic adhesive.

[0055] As a method of manufacturing the battery module 10 using the buffer material 14 , a known method can be used.

[0056] [Battery cell]

[0057] 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.

[0058] Hereinafter, a case where the battery cell 11 a is an all-solid-state lithium metal battery cell will be described.

[0059] 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.

[0060] The positive electrode current collector is not particularly limited, and an example thereof includes aluminum foil.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] The negative electrode current collector is not particularly limited, and examples thereof include copper foil.

[0065] 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.

[0066] Reference numerals

[0067] 10: Battery module

[0068] 11: Battery cell stack

[0069] 11a: Battery cell

[0070] 12: End plate

[0071] 13: Binding rod

[0072] 14: Buffer material

[0073] 14a: First elastic component

[0074] 14b: Second elastic member

[0075] 14c: Third elastic component

[0076] A: Contact area

[0077] E: Extension

[0078] F: Frame-like parts

[0079] G: Groove

[0080] W: corrugated leaf spring

[0081] R: concave part

[0082] C: convex part

Claims

1. A method for manufacturing a battery module, the 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; and In the aforementioned buffer material, a second elastic member is arranged inside a first elastic member having a frame-shaped member arranged on its outer periphery, and third elastic members are arranged on both sides of the second elastic member in the stacking direction of the battery cell stack. The second elastic member is formed by stacking corrugated leaf springs in the stacking direction of the battery cell stack. The manufacturing method of the battery module comprises the following steps: The second elastic member is formed by laminating a corrugated leaf spring inside the first elastic member; and The third elastic member is formed by foaming a resin inside the first elastic member on which the second elastic member is formed; and When the third elastic member is formed, the longitudinal end of the second elastic member is in contact with the frame-shaped member.

2. The method for manufacturing a battery module according to claim 1, wherein: The second elastic member is formed so as to have a plurality of contact areas in the width direction, wherein the contact areas are contact areas between the second elastic member and the bottom surface of the first elastic member. The corrugated leaf spring in contact with the contact region has an extension portion extending from the outermost contact region in the width direction toward the outer side in the width direction. The longer the distance of the extending portion in the width direction from the outermost contact region in the width direction is, the longer the distance in the thickness direction from the bottom surface of the first elastic member is.

3. The method for manufacturing a battery module according to claim 1 or 2, wherein: The cross-sectional shape of the bottom surface of the first elastic member is a wave shape corresponding to the cross-sectional shape of the wave-shaped leaf spring contacting the bottom surface of the first elastic member.

4. The method for manufacturing a battery module according to claim 1 or 2, wherein: The frame-shaped member has a groove-shaped portion formed in a region facing an end portion in the width direction of the second elastic member.

5. The method for manufacturing a battery module according to claim 4, wherein: The shapes of both side surfaces of the groove-shaped portion correspond to the shapes of the widthwise end portions of the second elastic member.

6. The method for manufacturing a battery module according to claim 1 or 2, wherein: The aforementioned battery cells are solid battery cells.

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