All-solid-state battery module

Abstract

To provide an all-solid-state battery module that can reduce the frictional force generated between an elastic body and a battery cell.SOLUTION: An all-solid-state battery module 1 includes: at least one battery cell 2; at least one elastic body 3 each disposed on the battery cell 2; and a friction-reducing material 5 disposed between the battery cell 2 and the elastic body 3. The battery cell 2 is pressurized to be compressed via the elastic body 3.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an all-solid-state battery module. [Background technology]

[0002] A known all-solid-state battery module has at least one battery cell and an elastic body disposed on the battery cell. In order to reduce contact resistance, the battery cell is compressed through the elastic body.

[0003] For example, Patent Document 1 (JP 2015-53261 A) discloses an all-solid-state battery in which a plurality of battery units are stacked, the battery units having a predetermined configuration, a heat dissipation member being interposed between each of the battery units, and the heat dissipation members being composed of a base layer having a specific configuration and a pair of thermally conductive elastic layers sandwiching the base layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-53261 A Summary of the Invention [Problem to be solved by the invention]

[0005] In an all-solid-state battery module in which the battery cells are pressurized via an elastic body, the elastic body itself is also compressed. The compressed elastic body is elastically distorted so as to expand in a direction perpendicular to the pressure direction (hereinafter, sometimes referred to as the planar direction). Here, the force applied to the elastic body may vary for various reasons. For example, the battery cell may expand and contract as it is charged and discharged. As the battery cell expands and contracts, the compression amount of the elastic body changes, and the deformation amount in the planar direction changes. When the deformation amount in the planar direction changes, a frictional force is generated between the battery cell and the elastic body. The frictional force may damage the battery cell. In particular, an all-solid-state battery module requires a high pressure force to obtain desired characteristics. Therefore, the effect of the frictional force is likely to be large, and damage to the battery cells is likely to become a problem.

[0006] Therefore, an object of the present invention is to provide an all-solid-state battery module that can reduce the frictional force generated between an elastic body and a battery cell. [Means for solving the problem]

[0007] In one embodiment, the all-solid-state battery module according to the present invention includes at least one battery cell, an elastic body disposed on the battery cell, and a friction-reducing material disposed between the battery cell and the elastic body. The battery cell is compressed via the elastic body. Effect of the Invention

[0008] According to the present invention, there is provided an all-solid-state battery module capable of reducing the frictional force generated between an elastic body and a battery cell. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an all-solid-state battery module according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing a reference example. [Diagram 3] FIG. 3 is a schematic diagram showing a modified example of the first embodiment. [Figure 4]FIG. 4 is a schematic diagram showing another modified example of the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing an all-solid-state battery module according to the second embodiment. [Figure 6] FIG. 6 is a schematic diagram showing an all-solid-state battery module according to the third embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an all-solid-state battery module according to an embodiment of the present invention will be described with reference to the drawings.

[0011] The all-solid-state battery module according to the present embodiment is a module formed by combining all-solid-state battery cells (battery cells) with other components. In this specification, the term "all-solid-state battery" refers to a secondary battery in which the positive electrode layer, the negative electrode layer, and the electrolyte layer are substantially made of solids. The "all-solid-state battery" may be any battery in which each layer can be said to be "substantially" solid, and may contain a small amount of liquid material. For example, even if a battery uses a small amount of liquid electrolyte in addition to a solid electrolyte as the electrolyte, it is included in the all-solid-state battery in this specification as long as each layer can be said to be substantially solid.

[0012] (First embodiment) FIG. 1 is a schematic diagram showing an all-solid-state battery module 1 according to a first embodiment. FIG. 1(a) shows the overall configuration of the all-solid-state battery module 1, and FIG. 1(b) shows a part of the configuration. As shown in FIG. 1(a), the all-solid-state battery module 1 has a plurality of battery cells 2, a plurality of elastic bodies 3, and a pair of end plates 4. The plurality of battery cells 2 and the plurality of elastic bodies 3 are stacked so as to be alternately stacked in the stacking direction. Therefore, it can be said that each elastic body 3 is disposed on each battery cell 2. The plurality of battery cells 2 and the plurality of elastic bodies 3 are sandwiched by the pair of end plates 4 in a compressed state. With such a configuration, each battery cell 2 is pressurized so as to be compressed via each elastic body 3.

[0013] As shown in FIG. 1(b), the battery cell 2 has an electrode stack 6 and an exterior material 7 that houses the electrode stack 6. The material of the exterior material 7 is not particularly limited, and for example, an aluminum laminate film can be used. Although not shown, the electrode stack 6 has a positive electrode layer, an electrolyte layer, and a negative electrode layer. Although not shown, a current collecting foil connected to the electrode stack 6 and the like are also arranged within the exterior material 7.

[0014] Here, in this embodiment, as shown in Fig. 1(b), a frictional force reduction material 5 is disposed between the exterior material 7 of the battery cell 2 and the elastic body 3. That is, the elastic body 3 and the frictional force reduction material 5 are disposed between the battery cells 2 adjacent to each other in the stacking direction. This prevents damage to the battery cells 2. This point will be described below with reference to a reference example.

[0015] FIG. 2 is a schematic diagram showing a reference example. In the reference example, the frictional force reducing material 5 is not provided. That is, the elastic body 3 is directly disposed on the battery cell 2. As described above, in the all-solid-state battery module 1, the compression amount of the elastic body 3 may change due to various reasons. For example, the thickness of the battery cell 2 may change with charging and discharging. When the thickness of the battery cell 2 increases, the compression amount of the elastic body 3 in the stacking direction increases. When the compression amount in the stacking direction increases, the elastic body 3 is distorted so as to expand in the planar direction. In FIG. 2, the elastic body 3 when the compression amount is small is shown as elastic body 3a, and the elastic body 3 when the compression amount is large is shown as elastic body 3b. When the compression amount of the elastic body 3 changes, the elastic body 3 expands in the planar direction, so frictional force is generated. This frictional force may damage the battery cell 2. For example, wrinkles may occur in the exterior material 7. Or, the current collecting foil disposed in the exterior material 7 may be torn.

[0016] In contrast, according to this embodiment, as shown in Fig. 1, friction-reducing materials 5 are arranged, which reduces the frictional force generated between the battery cells 2 and the elastic body 3. This prevents damage to the battery cells 2.

[0017] The above is an outline of this embodiment.

[0018] The material of the elastic body 3 is not particularly limited. For example, a resin sheet can be used as the elastic body 3. Examples of the resin sheet include a rubber sheet and a thermoplastic elastomer sheet.

[0019] The friction-reducing material 5 is not particularly limited as long as it is a material that can reduce the frictional force generated between the battery cell 2 and the elastic body 3 .

[0020] For example, a sheet material can be used as the friction-reducing material 5. In this case, a material that reduces the coefficient of friction between the battery cell 2 and the elastic body 3 can be used as the friction-reducing material 5. Specifically, a material can be used that makes the coefficient of friction between the friction-reducing material 5 and the elastic body 3 smaller than the coefficient of friction between the battery cell 2 and the elastic body 3 when the battery cell 2 and the elastic body 3 are in direct contact with each other.

[0021] In this specification, the term "friction coefficient" refers to both the kinetic and static coefficients of friction. For example, the fact that the friction coefficient at boundary A is greater than the friction coefficient at boundary B means that both the kinetic and static coefficients of friction are greater at boundary A than at boundary B.

[0022] Examples of sheet materials used as the frictional force reduction material 5 include resin sheets such as PP (polypropylene) sheets, PE (polypropylene) sheets, PI (polyimide) sheets, PC (polycarbonate) sheets, and PTFE (polytetrafluoroethylene) sheets.

[0023] When the frictional force reduction material 5 is a sheet material, it is preferable that the frictional force reduction material 5 is fixed to the battery cell 2 (the outer surface of the exterior material 7). This configuration prevents the frictional force reduction material 5 from shifting in the planar direction. The frictional force reduction material 5 can be fixed to the surface of the exterior material 7 via an adhesive, for example.

[0024] Alternatively, the friction-reducing material 5 can be realized by a lubricant layer containing a lubricant such as lubricating oil. The lubricant may be applied to the elastic body 3, or may be applied onto the battery cell 2 (exterior material 7). A lubricant is used that provides a smaller coefficient of friction between the battery cell 2 and the elastic body 3 when the lubricant is applied than the coefficient of friction between the battery cell 2 and the elastic body 3 when no lubricant is present.

[0025] As the lubricant, a flame-retardant hydraulic fluid is preferably used, for example, a phosphate-based hydraulic fluid, a fatty acid ester-based hydraulic fluid, a water-glycol-based hydraulic fluid, and an emulsion-based hydraulic fluid.

[0026] Next, the configuration of the battery cell 2 will be described. The configuration of the battery cell 2 is not particularly limited. However, the battery cell 2 preferably contains lithium metal or a lithium-containing alloy as the negative electrode active material. That is, the negative electrode layer of the electrode laminate 6 preferably contains lithium metal or a lithium-containing alloy as the negative electrode active material. The thickness of such a battery cell 2 changes significantly with charging and discharging. Specifically, the thickness increases in a charged state and decreases in a discharged state. As a result, the compression amount of the elastic body 3 changes significantly with charging and discharging. As a result, a large frictional force is repeatedly generated. Therefore, damage to the battery cell 2 is likely to be a problem. In an all-solid-state battery module 1 having such a battery cell 2, the value of reducing the frictional force according to this embodiment is great.

[0027] Next, the size of the frictional force reducing material 5 will be described.

[0028] Fig. 3 is a schematic diagram showing a modified example of this embodiment. This modified example relates to the size of the frictional force reduction material 5. For ease of viewing, the battery cell 2 and the frictional force reduction material 5 are depicted separated in Fig. 3.

[0029] In this modified example, the frictional force reduction material 5 is a sheet material. When the battery cell 2 is viewed from the elastic body 3 side (when viewed along the stacking direction), the size of the frictional force reduction material 5 is larger than the size of the electrode laminate 6. Specifically, when viewed along the stacking direction, the outer circumferential edge a of the frictional force reduction material 5 is located outside the outer circumferential edge b of the electrode laminate 6.

[0030] According to the modification shown in FIG. 3, damage to the battery cell 2 due to frictional force is more reliably prevented. The part of the battery cell 2 where high frictional force occurs between the elastic body 3 is a part having a certain thickness, specifically, a part where the electrode laminate 6 is provided. If the outer peripheral end a of the frictional force reduction material 5 is located inside the outer peripheral end b of the electrode laminate 6, a large frictional force may occur on the battery cell 2 at the part where the electrode laminate 6 protrudes from the frictional force reduction material 5. This may cause damage to the battery cell 2. In contrast, according to the modification shown in FIG. 3, the electrode laminate 6 is entirely covered by the frictional force reduction material 5, so that no large frictional force occurs outside the frictional force reduction material 5. This makes it possible to more reliably prevent damage to the battery cell 2.

[0031] The electrode laminate 6 is a portion having a positive electrode layer, an electrolyte layer, and a negative electrode layer. When the positive electrode layer, the electrolyte layer, and the negative electrode layer have different sizes, the "periphery b of the electrode laminate 6" refers to the outermost peripheral edge among the peripheral edges of the positive electrode layer, the electrolyte layer, and the negative electrode layer.

[0032] Next, another modified example will be described. FIG. 4 is a schematic diagram showing another modified example of the present embodiment. In this modified example, the relationship between the size of the frictional force reduction material 5 and the size of the elastic body 3 is specified. Specifically, the frictional force reduction material 5 is sheet-shaped. When the battery cell 2 is viewed from the elastic body 3 side (when viewed along the stacking direction), the outer peripheral end a of the frictional force reduction material 5 is located outside the outer peripheral end b of the elastic body 3. With this configuration, when viewed along the stacking direction, the elastic body 3 does not protrude outside the frictional force reduction material 5. Therefore, it is possible to prevent a large frictional force from being generated in the battery cell 2 at the portion protruding from the frictional force reduction material 5, and to more reliably prevent damage to the battery cell 2.

[0033] In FIG. 4, the elastic body 3 when the amount of compression is the smallest is shown as the elastic body 3a, and the elastic body 3 when the amount of compression is the largest is shown as the elastic body 3b. As shown in FIG. 4, when the most compressed state of the elastic body 3 can be specified, it is preferable that the outer peripheral end a of the frictional force reducing material 5 is located outside the outer peripheral end b of the elastic body 3b when it is most compressed. For example, in a battery cell 2 containing lithium metal or a lithium-containing alloy as the negative electrode active material, the thickness of the battery cell 2 becomes maximum when fully charged, and the amount of compression of the elastic body 3 becomes maximum. In such a case, it is preferable that the outer peripheral end a of the frictional force reducing material 5 is located outside the outer peripheral end b of the elastic body 3b when fully charged. By adopting such a configuration, the outer peripheral end a of the frictional force reducing material 5 is always located outside the outer peripheral end b of the elastic body 3. Therefore, it is always possible to prevent a large frictional force from being generated in the battery cell 2 at the portion where the elastic body 3 protrudes from the frictional force reducing material 5.

[0034] In the present embodiment, a case has been described in which a plurality of battery cells 2 and a plurality of elastic bodies 3 are provided. However, it is not necessary to provide a plurality of battery cells 2 and a plurality of elastic bodies 3. It is sufficient that the all-solid-state battery module 1 is provided with at least one battery cell 2 and at least one elastic body 3.

[0035] The use of the all-solid-state battery module 1 according to this embodiment is not particularly limited. For example, the all-solid-state battery module 1 can be used for an electric vehicle (EV).

[0036] Second Embodiment Next, a second embodiment will be described. Fig. 5 is a schematic cross-sectional view showing an all-solid-state battery module 1 according to this embodiment. Note that detailed description of the points where the same configuration as in the first embodiment can be adopted will be omitted.

[0037] When the friction-reducing material 5 is provided, the frictional force is reduced, and as a result, the battery cells 2 are more likely to shift in the planar direction. Therefore, in this embodiment, some effort is made to prevent the battery cells 2 from shifting in the planar direction.

[0038] Specifically, a module frame 8 is added as shown in Fig. 5. The module frame 8 extends along the stacking direction. The module frame 8 is fixed to a pair of end plates 4.

[0039] The module frame 8 is provided to prevent misalignment of the battery cells 2. That is, the ends of each battery cell 2 are connected to the module frame 8 so that each battery cell 2 does not shift in the planar direction.

[0040] The manner of connection between the module frame 8 and the ends of the battery cells 2 is not particularly limited. A frame material (not shown) having a through hole is provided at the end of the battery cells 2. A columnar member is used as the module frame 8. The module frame 8 is then arranged so that it passes through the through hole of the frame material. With this configuration, the battery cells 2 can be connected to the module frame 8 without shifting in the direction perpendicular to the stacking direction.

[0041] According to this embodiment, it is possible to prevent displacement of the battery cells 2 despite the provision of the frictional force reduction material 5. As a result, it becomes easier to use, as the frictional force reduction material 5, a material that reduces the coefficient of friction between the battery cells 2 and the elastic body 3.

[0042] (Third embodiment) Next, a third embodiment will be described. Note that detailed description will be omitted for the points where the same configuration as in the above-described embodiments can be adopted.

[0043] Fig. 6 is a schematic diagram showing an all-solid-state battery module 1 according to this embodiment. Fig. 6 shows the overall configuration of the all-solid-state battery module 1 and a partially enlarged view.

[0044] In this embodiment, as in the second embodiment, some effort has been made to prevent the battery cells 2 from shifting in position. In this embodiment, some effort has been made to configure the elastic body 3 arranged between the battery cells 2 and the end plates 4. That is, some effort has been made to configure the elastic body 3 arranged at the outermost position in the stacking direction. Hereinafter, the elastic body 3 arranged at the outermost position in the stacking direction is referred to as the "outermost elastic body 3A."

[0045] The outermost elastic body 3A is sheet-shaped. The outermost elastic body 3A has an inner surface a facing the battery cell 2 and an outer surface b on the opposite side. The inner surface a and the outer surface b have different surface conditions.

[0046] Specifically, the coefficient of friction between the outer surface b and the end plate 4 is greater than the coefficient of friction between the inner surface a and the end plate 4 when the inner surface a is in contact with the end plate 4 .

[0047] According to this embodiment, it is possible to prevent the battery cell 2 from being displaced in the planar direction. That is, it is preferable that the inner surface a of the outermost elastic body 3A facing the battery cell 2 has a slippery surface state in order to reduce friction. On the other hand, if the outer surface b also has a slippery surface state like the inner surface a, the outermost elastic body 3A is likely to be displaced relative to the end plate 4. In contrast, according to this embodiment, the coefficient of friction between the outer surface b and the end plate 4 is larger than the coefficient of friction when the inner surface a is in contact with the end plate 4, so that it is possible to prevent the outermost elastic body 3A from being displaced relative to the end plate 4. This makes it possible to use a material as the frictional force reduction material 5 that reduces the coefficient of friction between the battery cell 2 and the elastic body 3.

[0048] The surface conditions of the inner surface a and the outer surface b can be made different, for example, by the surface roughness. Preferably, the surface roughness of the outer surface b is greater than the surface roughness of the inner surface a. With this configuration, the inner surface a has a slippery surface condition, and the outer surface b has a non-slippery surface condition.

[0049] The present invention has been described above with reference to the first to third embodiments. Representative configurations of the present invention will be summarized below together with their effects as supplementary notes.

[0050] (Appendix 1) An all-solid-state battery module 1 includes at least one battery cell 2, at least one elastic body 3 each disposed on the battery cell 2, and a frictional force reducing material 5 disposed between the battery cell 2 and the elastic body 3, and the battery cell 2 is pressurized so as to be compressed via the elastic body 3. With this configuration, the frictional force generated between the battery cell 2 and the elastic body 3 is reduced. Therefore, damage to the battery cell 2 due to the frictional force can be prevented.

[0051] (Appendix 2) The all-solid-state battery module 1 according to Supplementary Note 1, in which the battery cell 2 has lithium metal or a lithium-containing alloy as a negative electrode active material. In the case of such a configuration, the thickness of the battery cell 2 changes significantly during charging and discharging. Therefore, in general, the amount of compression of the elastic body 3 is likely to change, and frictional force is likely to occur. Therefore, it can be said that the provision of the frictional force reducing material 5 is of great value.

[0052] (Appendix 3) An all-solid-state battery module according to appendix 1 or 2, wherein the battery cell 2 has an electrode laminate 6 having a positive electrode layer, an electrolyte layer, and a negative electrode layer, and an exterior material 7 that houses the electrode laminate 6, and the frictional force reduction material 5 is disposed between the exterior material 7 and the elastic body 3. With this configuration, damage (creases) to the exterior material 7 due to friction between the exterior material 7 and the elastic body 3 can be prevented.

[0053] (Appendix 4) An all-solid-state battery module according to Supplementary Note 3, wherein the frictional force reduction material 5 is sheet-shaped, and when the battery cell 2 is viewed from the elastic body 3 side, the outer peripheral end a of the frictional force reduction material 5 is located outside the outer peripheral end b of the electrode laminate 6. This configuration prevents a large frictional force from being generated in the portion where the electrode laminate 6 protrudes from the frictional force reduction material 5. Damage to the battery cell 2 is more reliably prevented.

[0054] (Appendix 5) An all-solid-state battery module according to any one of Supplementary Notes 1 to 4, wherein the frictional force reduction materials 5 are fixed to the battery cells 2. With this configuration, it is possible to prevent the frictional force reduction materials 5 from shifting in position.

[0055] (Appendix 6) An all-solid-state battery module according to any one of Supplementary Notes 1 to 5, wherein the frictional force reduction material 5 is sheet-shaped, and when the battery cell 2 is viewed from the elastic body 3 side, an outer peripheral end a of the frictional force reduction material 5 is located outside an outer peripheral end b of the elastic body 3. This configuration prevents a large frictional force from being generated in the battery cell 2 outside the frictional force reduction material 5. Damage to the battery cell 2 is more reliably prevented.

[0056] (Appendix 7) An all-solid-state battery module according to any one of appendices 1 to 6, wherein a plurality of battery cells 2 are provided, and the elastic body 3 and the frictional force reducing material 5 are disposed between adjacent battery cells 2. All-solid-state battery module. According to such a configuration, in an all-solid-state battery module having a plurality of battery cells 2, damage to each battery cell 2 due to friction can be prevented.

[0057] (Appendix 8) The all-solid-state battery module according to any one of Supplementary Notes 1 to 7, further comprising a module frame 8 extending along a stacking direction, the battery cells 2 and the elastic body 3 being stacked along the stacking direction, and the ends of the battery cells 2 being connected to the module frame 8 so as not to shift the battery cells 2 in a direction perpendicular to the stacking direction. With this configuration, the positional shift of the battery cells 2 is prevented.

[0058] (Appendix 9) An all-solid-state battery module according to any one of Supplementary Notes 1 to 8, further comprising an end plate 4, wherein at least one elastic body 3 comprises an outermost elastic body 3A disposed between the battery cell 2 and the end plate 4, the outermost elastic body 3A being sheet-shaped, the outermost elastic body 3A having an inner surface a facing the battery cell 2 and an outer surface b opposite the inner surface a, the outer surface b having a different surface state from the inner surface a, and the coefficient of friction between the outer surface b and the end plate 4 being greater than the coefficient of friction between the inner surface a and the end plate 4 when the inner surface a is in contact with the end plate 4. With this configuration, displacement of the outermost elastic body 3A is prevented. [Explanation of symbols]

[0059] 1 All-solid-state battery module, 2 Battery cell, 3 Elastic body, 4 End plate, 5 Friction reduction material, 6 Electrode laminate, 7 Exterior material, 8 Module frame

Claims

1. At least one battery cell; At least one elastic body, each of which is disposed on the battery cell; A friction reduction material disposed between the battery cell and the elastic body; Equipped with The battery cell is compressed via the elastic body. All-solid-state battery module.

2. The all-solid-state battery module according to claim 1 , The battery cell has lithium metal or a lithium-containing alloy as a negative electrode active material. All-solid-state battery module.

3. The all-solid-state battery module according to claim 1 or 2, The battery cell includes: an electrode stack having a positive electrode layer, an electrolyte layer, and a negative electrode layer; and an exterior material that houses the electrode stack, The friction reduction material is disposed between the exterior material and the elastic body. All-solid-state battery module.

4. The all-solid-state battery module according to claim 3 , The friction reduction material is in a sheet form, When the battery cell is viewed from the elastic body side, an outer peripheral edge of the frictional force reduction material is located outside an outer peripheral edge of the electrode stack. All-solid-state battery module.

5. The all-solid-state battery module according to claim 1 or 2, The friction reduction material is fixed to the battery cell. All-solid-state battery module.

6. The all-solid-state battery module according to claim 1 or 2, The friction reduction material is in a sheet form, When the battery cell is viewed from the elastic body side, an outer circumferential edge of the frictional force reduction material is located outside an outer circumferential edge of the elastic body. All-solid-state battery module.

7. The all-solid-state battery module according to claim 1 or 2, The battery cell is provided in plurality, The elastic body and the frictional force reducing material are disposed between adjacent battery cells. All-solid-state battery module.

8. The all-solid-state battery module according to claim 1 or 2, Furthermore, A module frame extending along the stacking direction is provided, the battery cells and the elastic body are stacked along the stacking direction, an end portion of the battery cell is connected to the module frame so as to prevent the battery cell from shifting in a direction perpendicular to the stacking direction; All-solid-state battery module.

9. The all-solid-state battery module according to claim 1 or 2, Furthermore, having an end plate, the at least one elastic body includes an outermost elastic body disposed between the battery cell and the end plate; The outermost elastic body is in a sheet shape, The outermost elastic body is An inner surface facing the battery cell; an outer surface opposite the inner surface, the outer surface having a different surface condition from the inner surface; The coefficient of friction between the outer surface and the end plate is greater than the coefficient of friction between the inner surface and the end plate when the inner surface is in contact with the end plate. All-solid-state battery module.

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