Battery module and method for manufacturing the battery module

Abstract

To improve workability for manufacturing a battery module.SOLUTION: A battery module 10 includes a plurality of battery cells 100 and a functional material 200. The functional material 200 exists between the adjacent cells 100. The functional material 200 includes an elastic particle 210 and a binder 220. The elastic particle 210 is dispersed in the binder 220.SELECTED DRAWING: Figure 2

Description

[Technical Field]

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

[0002] In recent years, various battery modules have been developed that include a plurality of battery cells. In a battery module, the plurality of battery cells are arranged in a predetermined direction.

[0003] Patent Document 1 describes an example of a battery module. This battery module includes spacers positioned between adjacent battery cells. The spacers are made of a thermosetting resin.

[0004] Patent Document 2 describes an example of a battery module. This battery module includes a spacer positioned between adjacent battery cells. The spacer includes a packaging body and a plurality of granular bodies. The plurality of granular bodies are contained in the packaging body.

[0005] Patent Document 3 describes an example of a battery module. This battery module includes an elastic adhesive, which is positioned between adjacent battery modules. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-097693 [Patent Document 2] Japanese Patent Application Laid-Open No. 2014-072055 [Patent Document 3] International Publication No. 2018 / 163708 Summary of the Invention [Problem to be solved by the invention]

[0007] Compression pads such as urethane sheets are sometimes provided between adjacent battery cells. However, when compression pads are used, the size of the compression pads needs to be adjusted depending on the size of the battery cells. In particular, as the size of the battery cells increases, the size of the compression pads also increases. In this case, certain factors such as static electricity can make the compression pads difficult to handle. Furthermore, when a compression pad is used, it may be necessary to peel off a sheet such as a PET (polyethylene terephthalate) film provided on one side of the compression pad. Therefore, when a compression pad is provided between adjacent battery cells, the workability of manufacturing a battery module may be reduced.

[0008] An example of an object of the present invention is to improve the workability for manufacturing a battery module. Other objects of the present invention will become apparent from the description of this specification. [Means for solving the problem]

[0009] One aspect of the present invention is as follows. [1] A plurality of battery cells; a functional material positioned between adjacent battery cells; Equipped with The functional material includes elastic particles and a binder in which the elastic particles are dispersed. [2] The compressive deflection of the functional material at 25°C and 10% deflection is 3.0 kPa or more and 10 kPa or less, The battery module according to [1], wherein the compressive deflection of the functional material at 70°C and 70% deflection is 0.40 MPa or more and 0.60 MPa or less. [3] The battery module according to [1] or [2], wherein the elastic particles are hollow resin particles. [4] The battery module according to any one of [1] to [3], wherein the binder is an acrylic resin. [5] applying a slurry containing elastic particles and a binder to a battery cell; curing the binder; A method for manufacturing a battery module comprising: [6] After the step of hardening the binder, the functional material containing the elastic particles and the binder has a compressive deflection of 3.0 kPa or more and 10 kPa or less at 25°C and 10% deflection; [5] The method for manufacturing a battery module according to [5], wherein after the step of hardening the binder, the compressive deflection of the functional material at 70°C and 70% deflection is 0.40 MPa or more and 0.60 MPa or less. [7] The method for manufacturing a battery module according to [5] or [6], wherein the elastic particles are hollow resin particles. [8] The method for manufacturing a battery module according to any one of [5] to [7], wherein the binder is an acrylic resin. [9] The method for manufacturing a battery module according to any one of [5] to [8], wherein in the step of curing the binder, the binder is cured by irradiating the binder with light. [Effects of the Invention]

[0010] According to the above aspect of the present invention, the workability for manufacturing the battery module can be improved. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a battery module according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view schematically illustrating the AA′ cross section of FIG. [Figure 3] 5A to 5C are diagrams for explaining a manufacturing method of a battery module according to an embodiment. [Figure 4] 5A to 5C are diagrams for explaining a manufacturing method of a battery module according to an embodiment. [Figure 5] FIG. 10 is a perspective view of a battery module according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments and modifications of the present invention will be described with reference to the drawings. In all the drawings, like components are designated by like reference numerals, and descriptions thereof will be omitted as appropriate.

[0013] Fig. 1 is a perspective view of a battery module 10 according to an embodiment. Fig. 2 is a schematic cross-sectional view taken along line AA' in Fig. 1.

[0014] For the purpose of explanation, the X, Y, and Z directions are shown in each figure. The X direction indicates the longitudinal direction of the battery cell 100, which will be described later. The Y direction is perpendicular to the X direction. The Y direction indicates the thickness direction of the battery cell 100. The Z direction is perpendicular to both the X and Y directions. The Z direction indicates the width direction of the battery cell 100. Hereinafter, the direction perpendicular to the Y direction will be referred to as the XZ plane direction, as necessary.

[0015] As shown in FIGS. 1 and 2 , a battery module 10 includes a plurality of battery cells 100 and a plurality of functional materials 200. The plurality of battery cells 100 and the plurality of functional materials 200 are arranged alternately in the Y direction. As a result, each functional material 200 is located between adjacent battery cells 100 in the Y direction. The battery module 10 is arranged, for example, with the Z direction approximately parallel to the vertical direction and the X and Y directions approximately parallel to a horizontal direction perpendicular to the vertical direction. The battery module 10 is housed, for example, in a housing (not shown). However, the arrangement of the battery module 10 is not limited to this example.

[0016] The plurality of battery cells 100 will be described with reference to Fig. 1. For the sake of explanation, six battery cells 100 are shown schematically in Fig. 1. However, the number of battery cells 100 included in the battery module 10 is not limited to the example shown in Fig. 1.

[0017] Each battery cell 100 has an exterior casing 102, a positive electrode tab 112, and a negative electrode tab 114. The exterior casing 102 seals a battery element (not shown) and an electrolyte (not shown). The battery element includes a plurality of positive electrodes and a plurality of negative electrodes alternately stacked in the Y direction, and a separator positioned between the positive electrodes and negative electrodes adjacent in the Y direction. The positive electrode tab 112 and the negative electrode tab 114 are drawn out from opposite sides of the exterior casing 102 in the X direction. The positive electrode tab 112 is electrically connected to the plurality of positive electrodes. The negative electrode tab 114 is electrically connected to the plurality of negative electrodes. However, the structure of the battery cell 100 is not limited to the example described above.

[0018] In the embodiment, the multiple battery cells 100 arranged in the Y direction are connected in series in order from the battery cells 100 on one side in the Y direction to the battery cells 100 on the other side in the Y direction. Specifically, the positive electrode tab 112 and the negative electrode tab 114 drawn from one of two adjacent battery cells 100 in the Y direction and the positive electrode tab 112 and the negative electrode tab 114 drawn from the other of two adjacent battery cells 100 in the Y direction are oriented opposite to each other in the X direction. On one side in the X direction of two adjacent battery cells 100 in the Y direction, the positive electrode tab 112 drawn from one battery cell 100 and the negative electrode tab 114 drawn from the other battery cell 100 are joined to each other by, for example, laser welding. For example, the positive electrode tab 112 drawn from the topmost battery cell 100 in FIG. 1 to the left in FIG. 1 and the negative electrode tab 114 drawn from the second battery cell 100 from the top in FIG. 1 to the left in FIG. 1 are joined to each other. 1. In addition, the positive electrode tab 112 extending from the second battery cell 100 from the top to the right side in Fig. 1 and the negative electrode tab 114 extending from the third battery cell 100 from the top to the right side in Fig. 1 are joined together. In this way, in the multiple battery cells 100, the joints between the positive electrode tabs 112 and negative electrode tabs 114 on the left side in Fig. 1 and the joints between the positive electrode tabs 112 and negative electrode tabs 114 on the right side in Fig. 1 are arranged alternately.

[0019] Referring to FIG. 2, the functional materials 200 will be described.

[0020] Each functional material 200 includes elastic particles 210 and a binder 220. The elastic particles 210 are dispersed within the binder 220.

[0021] In the embodiment, the elastic particles 210 are hollow resin particles. The elastic particles 210 are made of, for example, an acrylic-styrene copolymer. For example, the elastic modulus of the material of the elastic particles 210 is lower than the elastic modulus of the material of the binder 220. The elastic modulus of the material of the elastic particles 210 is, for example, 1 GPa or more and 20 GPa or less. In the embodiment, the elastic particles 210 have a hollow, approximately spherical shell shape. The particle diameter of the elastic particles 210 is, for example, 75 μm or more and 300 μm or less. The inner pore diameter of the elastic particles 210 is, for example, 50 μm or more and 200 μm or less. However, the material and structure of the elastic particles 210 are not limited to this example. Note that the elastic particles 210 shown in FIG. 2 are schematically shown as being crushed in the Y direction due to compression in the Y direction of adjacent battery cells 100 in the Y direction.

[0022] In the embodiment, the binder 220 is made of resin. Specifically, the binder 220 is, for example, a cured acrylic resin. The binder 220 can be, for example, an ultraviolet-cured acrylic resin. In the example shown in FIG. 2, the binder 220 is a cured resin. However, the material of the binder 220 is not limited to this example. The binder 220 is bonded to two battery cells 100 located on both sides of the binder 220 in the Y direction. The adhesive strength between the battery cells 100 and the binder 220 is, for example, approximately 10 kPa. However, this adhesive strength is not limited to this example.

[0023] The thickness of the functional material 200 in the Y direction when it is not compressed in the Y direction by the battery cell 100 is, for example, 0.10 mm or more and 1.5 mm or less. However, the thickness of the functional material 200 in the Y direction is not limited to this example.

[0024] The porosity of the portion of the functional material 200 not occupied by the elastic particles 210 is, for example, 60 volume % or more and 70 volume % or less with respect to the total volume of the functional material 200. When the porosity is equal to or more than the lower limit, the functional material 200 can be easily compressed in the Y direction. When the porosity is equal to or less than the upper limit, the strength of the functional material 200 can be improved. However, the porosity is not limited to this example. The porosity is measured, for example, by observing a cross section of the functional material 200 perpendicular to the X direction with a scanning electron microscope (SEM).

[0025] In the embodiment, the functional material 200 functions as a fixing material that fixes the battery cells 100 arranged in the Y direction. An external force may be applied to the battery module 10, for example, due to an impact to the battery module 10 or vibration of an automobile in which the battery module 10 is mounted. In the embodiment, even if such a force is applied to the battery module 10, the functional material 200 can suppress displacement of each battery cell 100 in the XZ plane direction.

[0026] In the embodiment, the functional material 200 functions as a fixing material that fixes the multiple positive electrodes and multiple negative electrodes provided inside each exterior material 102. The functional material 200 is compressed in the Y direction by the battery cells 100 adjacent in the Y direction. The functional material 200 is elastically deformable in the Y direction due to the elastic particles 210. Therefore, each battery cell 100 receives a pressure from the functional material 200. Therefore, the pressure from the functional material 200 can suppress displacement of the multiple positive electrodes and multiple negative electrodes provided inside the exterior material 102 in the XZ plane direction.

[0027] In the embodiment, the functional material 200 functions as a buffer material that deforms in response to swelling of the battery cell 100 in the Y direction. When the battery cell 100 is charged, the battery cell 100 may swell in the Y direction. As described above, the functional material 200 is elastically deformable in the Y direction due to the elastic particles 210. Therefore, when the battery cell 100 swells in the Y direction, the functional material 200 can contract in the Y direction in response to the swelling of the battery cell 100 in the Y direction.

[0028] The compressive deflection of the functional material 200 at 25°C and 10% deflection can be, for example, 3.0 kPa or more and 10 kPa or less. For example, when the battery module 10 is in an initial state or when the battery module 10 is in a discharged state, the temperature of the functional material 200 is approximately 25°C. If the compressive deflection in this state is equal to or greater than the above-mentioned lower limit, it is possible to suppress displacement of each battery cell 100 in the XZ plane direction and displacement of the multiple positive electrodes and multiple negative electrodes provided inside each exterior material 102 in the XZ plane direction. If the compressive deflection in the above-mentioned state is equal to or less than the above-mentioned upper limit, it is possible to suppress displacement of the battery cell 100, the multiple positive electrodes provided inside each exterior material 102, and multiple loads due to compression of the functional material 200 in the Y direction.

[0029] The compressive deflection of the functional material 200 at 70°C and 70% deflection can be, for example, 0.40 MPa or more and 0.60 MPa or less. For example, when the battery module 10 is in a charged state, the temperature of the functional material 200 is approximately 70°C. In this state, if the compressive deflection is equal to or greater than the above-mentioned lower limit, it is possible to suppress displacement of each battery cell 100 in the XZ plane direction and displacement of the multiple positive electrodes and multiple negative electrodes provided inside each exterior material 102 in the XZ plane direction. In the above state, if the compressive deflection is equal to or less than the above-mentioned upper limit, it is possible to suppress displacement of the battery cell 100, the multiple positive electrodes provided inside each exterior material 102, and multiple loads due to compression of the functional material 200 in the Y direction.

[0030] The compression deflection mentioned above is measured in accordance with ASTM D3574.

[0031] 3 and 4 are diagrams illustrating a manufacturing method of a battery module 10 according to an embodiment. The battery module 10 according to an embodiment is manufactured as follows. In the description using FIGS. 3 and 4, unless otherwise specified, the Y direction is approximately parallel to the vertical direction, and the X and Z directions are approximately parallel to the horizontal direction. Furthermore, unless otherwise specified, the tip side of the arrow indicating the Y direction is above the vertical direction, and the base end side of the arrow indicating the Y direction is below the vertical direction.

[0032] First, a slurry 200' containing elastic particles 210 and a binder 220 is prepared.

[0033] Next, as shown in FIG. 3, a slurry 200′ is applied to the upper surface of the exterior packaging material 102. In the example shown in FIG. 3, the slurry 200′ is dropped from a nozzle 310 positioned above the exterior packaging material 102. Therefore, by moving the nozzle 310, the slurry 200′ can be applied to a desired area on the upper surface of the exterior packaging material 102. Therefore, compared to when a compression pad such as a urethane sheet is cut to a predetermined size corresponding to the size of the upper surface of the exterior packaging material 102 and then attached to the upper surface of the exterior packaging material 102, the area where the functional material 200 is formed can be easily adjusted. Furthermore, in the embodiment, compared to when a compression pad such as a urethane sheet is used, peeling off a sheet such as a PET film from the compression pad is not necessary. Therefore, in the embodiment, the manufacturing time of the battery module 10 can be shortened compared to when a compression pad is used. Therefore, in the embodiment, the workability for manufacturing the battery module 10 can be improved. The slurry 200′ is applied to an area of, for example, 75% to 100% of the upper surface of the exterior packaging material 102.

[0034] Next, as shown in Fig. 4, the slurry 200' is irradiated with ultraviolet light 322. In the example shown in Fig. 4, the ultraviolet light 322 is irradiated from a light source 320 positioned above the battery cell 100. The binder 220 is hardened by the ultraviolet light 322. As a result, the slurry 200' becomes the functional material 200. The functional material 200 is adhered to the upper surface of the exterior material 102.

[0035] The method for curing the binder 220 is not limited to the photo-curing shown in Fig. 4. The binder 220 may be cured by, for example, heat curing.

[0036] Next, another battery cell 100 is stacked on the upper surface side of the battery cell 100 on which the functional material 200 is formed. As a result, the upper surface of the functional material 200 and the lower surface of the other battery cell 100 are bonded to each other. In this case, the adhesive strength between the lower surface of the functional material 200 and the upper surface of the battery cell 100 located below the functional material 200 is, for example, almost equal to the adhesive strength between the upper surface of the functional material 200 and the lower surface of the other battery cell 100 located above the functional material 200. Next, the functional material 200 is formed on the upper surface of the other battery cell 100 in the same manner as described with reference to FIGS. 3 and 4. In this manner, a predetermined number of battery cells 100 and functional materials 200 are alternately stacked in the Y direction to manufacture a plurality of battery modules 10.

[0037] 5 is a perspective view of a battery module 10A according to a modified example. The battery module 10A according to the modified example is similar to the battery module 10 according to the embodiment, except for the following points.

[0038] A battery module 10A according to a modified example includes multiple cell groups 100G. For ease of explanation, FIG. 5 shows three cell groups 100G. However, the number of cell groups 100G included in the battery module 10A is not limited to the example shown in FIG. 5. Each cell group 100G includes two battery cells 100. However, the number of battery cells 100 included in each cell group 100G is not limited to two and may be three or more. Each cell group 100G includes a positive electrode tab group 112G and a negative electrode tab group 114G. The positive electrode tab group 112G includes multiple positive electrode tabs 112 drawn from the multiple battery cells 100 included in each cell group 100G. The negative electrode tab group 114G includes multiple negative electrode tabs 114 drawn from the multiple battery cells 100 included in each cell group 100G.

[0039] The multiple battery cells 100 included in each cell group 100G are connected in parallel. The multiple cell groups 100G stacked in the Y direction are connected in series from the cell group 100G on one side in the Y direction to the cell group 100G on the other side in the Y direction. Specifically, the positive electrode tab group 112G and the negative electrode tab group 114G drawn from one of two cell groups 100G adjacent in the Y direction and the positive electrode tab group 112G and the negative electrode tab group 114G drawn from the other of two cell groups 100G adjacent in the Y direction are oriented opposite to each other in the X direction. On one side in the X direction of two cell groups 100G adjacent in the Y direction, the positive electrode tab group 112G drawn from one cell group 100G and the negative electrode tab group 114G drawn from the other cell group 100G are joined to each other by, for example, laser welding. For example, the positive electrode tab group 112G extended from the top cell group 100G in Fig. 5 to the left side in Fig. 5 and the negative electrode tab group 114G extended from the second cell group 100G from the top to the left side in Fig. 5 are joined to each other. Also, the positive electrode tab group 112G extended from the second cell group 100G from the top to the right side in Fig. 5 and the negative electrode tab group 114G extended from the third cell group 100G from the top to the right side in Fig. 5 are joined to each other. In this way, in the multiple cell groups 100G, the joint portion between the positive electrode tab group 112G and the negative electrode tab group 114G on the left side in Fig. 5 and the joint portion between the positive electrode tab group 112G and the negative electrode tab group 114G on the right side in Fig. 5 are arranged alternately.

[0040] 5, the functional material 200 can be provided between the battery cells 100 adjacent to each other in the Y direction, in the same manner as in the embodiment. Therefore, in the modified example as well, the workability for manufacturing the battery module 10A can be improved, in the same manner as in the embodiment.

[0041] Although the embodiments and modifications of the present invention have been described above with reference to the drawings, these are merely examples of the present invention, and various configurations other than those described above can also be adopted. [Explanation of symbols]

[0042] 10,10A battery module 100 battery cells 100G cell group 102 Exterior materials 112 Positive electrode tab 112G Positive electrode tab group 114 Negative electrode tab 114G negative electrode tab group 200 Functional Materials 210 Elastic Particles 220 Binder 310 nozzle 320 light source 322 UV rays

Claims

1. A plurality of battery cells; a functional material positioned between adjacent battery cells; Equipped with the functional material includes elastic particles and a binder in which the elastic particles are dispersed, The compressive deflection of the functional material at 25°C and 10% deflection is 3.0 kPa or more and 10 kPa or less, The battery module, wherein the functional material has a compressive deflection of 0.40 MPa or more and 0.60 MPa or less at 70°C and 70% deflection.

2. The battery module according to claim 1 , wherein the elastic particles are hollow resin particles.

3. The battery module according to claim 1 or 2, wherein the binder is an acrylic resin.

4. A method of manufacturing a battery cell, comprising: applying a slurry containing elastic particles and a binder to the battery cell; curing the binder; Equipped with After the step of hardening the binder, the compressive deflection of the functional material containing the elastic particles and the binder at 25°C and 10% deflection is 3.0 kPa or more and 10 kPa or less; the functional material has a compressive deflection of 0.40 MPa or more and 0.60 MPa or less at 70° C. and 70% deflection after the step of hardening the binder.

5. The method for manufacturing a battery module according to claim 4 , wherein the elastic particles are hollow resin particles.

6. The method for manufacturing a battery module according to claim 4 or 5, wherein the binder is an acrylic resin.

7. The method for manufacturing a battery module according to claim 4 or 5, wherein in the step of curing the binder, the binder is cured by irradiating the binder with light.

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