Battery module

Abstract

To provide a battery module that can suppress the occurrence of wrinkles in the current collection section. [Solution] The battery module comprises an outer casing that houses a stack of energy storage modules, the outer casing comprising a current collector that conducts current from the stack of energy storage modules and a laminate seal portion that welds the outer casings together, the current collector and the laminate seal portion being joined by a sealing material, the sealing material being discontinuously arranged around the periphery of the current collector.

Description

Technical Field

[0006] , , ,

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[0001] The present disclosure relates to a battery module.

Background Art

[0002] Patent Document 1 discloses an exterior body of a battery module including a current collector (metal sheet) and a laminate sheet surrounding the current collector.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the battery module disclosed in Patent Document 1, the current collector and the laminate seal part are joined by a long sealing material. However, when such a long sealing material is welded using, for example, a long heater, the stress on the current collector increases due to the shrinkage of the sealing material, and wrinkles may occur in the current collector. As a result, there is a risk of poor quality of the battery module (for example, incorrect height dimension).

[0005] The present disclosure has been made in view of the above, and an object thereof is to provide a battery module capable of suppressing the occurrence of wrinkles in the current collector.

Means for Solving the Problems

[0006] The battery module according to the present disclosure includes an exterior body that houses a power storage module laminate, the exterior body includes a current collector that conducts electricity from the power storage module laminate, and a laminate seal part that welds the exterior bodies together, the current collector and the laminate seal part are joined by a sealing material, and the sealing material is discontinuously arranged at the peripheral edge of the current collector. [Effects of the Invention]

[0007] According to this disclosure, stress concentration on the current collector section due to the sealing material can be dispersed and mitigated, thereby suppressing the occurrence of wrinkles in the current collector section. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a cross-sectional view showing the configuration of the peripheral edge of a battery module according to an embodiment. [Figure 2] Figure 2 is a diagram illustrating a first aspect of the sealing material in the battery module according to the embodiment, and is a plan view showing the current collector and the sealing material as seen from above. [Figure 3] Figure 3 is a diagram illustrating a second aspect of the sealing material in the battery module according to the embodiment, and is a plan view showing the peripheral edge of the current collector and the sealing material arranged on the peripheral edge as seen from above. [Figure 4] Figure 4 is a diagram illustrating a third aspect of the sealing material in the battery module according to the embodiment, and is a side view showing the peripheral edge of the current collector and the sealing material arranged on the peripheral edge as viewed from the side. [Modes for carrying out the invention]

[0009] A battery module according to an embodiment of this disclosure will be described with reference to the drawings. Note that the components in the following embodiments include those that are easily replaceable or substantially identical to those that are replaceable by a person skilled in the art.

[0010] The configuration of the battery module according to this embodiment will be described with reference to Figures 1 and 2. The battery module according to this embodiment can be used as a battery for, for example, a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), or a battery electric vehicle (BEV).

[0011] Figure 1 is a cross-sectional view showing the peripheral structure of the battery module 1. As shown in Figure 1, the battery module 1 comprises a stack of energy storage modules 11 and an outer casing 12. This battery module 1 is a laminated type battery module in which the stack of energy storage modules 11 is encased by the outer casing 12.

[0012] The energy storage module laminate 11 has, for example, multiple electrodes and multiple electrolyte layers, and these electrodes and electrolyte layers are stacked alternately. The energy storage module laminate 11 is, for example, a non-aqueous secondary battery or an all-solid-state secondary battery. In the following description, we will assume that the energy storage module laminate 11 is a bipolar type non-aqueous lithium-ion secondary battery.

[0013] The outer casing 12 is for housing the energy storage module stack 11. The outer casing 12 comprises a current collector 121, a laminate seal 122, and a sealing material 123. Although only a portion of the outer casing 12 is shown in Figure 1, the outer casing 12 actually seals the energy storage module stack 11.

[0014] The current collector 121 is for supplying power from the energy storage module stack 11. The current collector 121 is a sheet-shaped conductive material, and is composed of metal foil such as aluminum, stainless steel, iron, copper, titanium, or nickel.

[0015] The laminate seal portion 122 is for welding the outer casings 12 together. Although not shown in Figure 1, other battery modules 1 are placed above and below the battery module 1, and the outer casings 12 are welded together via the sealing material 123. Also, although the outer side (right side of the page) of the upper and lower laminate seal portions 122 of the energy storage module stack 11 is not shown in Figure 1, the outer ends of the upper and lower laminate seal portions 122 are joined together.

[0016] The laminated seal portion 122 is formed in a rectangular frame shape when viewed from above, as in Figure 2, and is welded to the periphery of the current collector portion 121 by the sealing material 123. Specifically, the laminated seal portion 122 has a three-layer structure consisting of a first resin layer 122a, a metal layer 122b, and a second resin layer 122c.

[0017] The first resin layer 122a functions as a sealant layer and a protective layer. As the material for the first resin layer 122a, for example, polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polystyrene, polyvinyl chloride, and nylon can be used.

[0018] The metal layer 122b functions as a gas barrier layer. For example, aluminum, iron, stainless steel, etc., can be used as the material for the metal layer 122b.

[0019] The second resin layer 122c functions as a sealant layer. As the material for the second resin layer 122c, for example, polyolefins such as polyethylene (PE) and polypropylene (PP), polyesters such as polyethylene terephthalate (PET), polystyrene, polyvinyl chloride, and nylon can be used.

[0020] The sealing material 123 is for joining (welding) the current collector part 121 and the laminate sealing part 122. The material of the sealing material 123 is not particularly limited, and for example, it can be widely selected from materials that can chemically bond with the metal constituting the current collector part 121. Also, as shown in FIG. 2, the sealing material 123 is discontinuously arranged at the peripheral part of the current collector part 121.

[0021] FIG. 2 is a plan view of the current collector part 121 and the sealing material 123 in the battery module 1 when viewed from above. Also, the sealing material 123 shown in FIG. 2 shows, for example, the state before welding the laminate sealing part 122 to the current collector part 121. A plurality of strip-shaped sealing materials 123 are arranged at the peripheral part of the current collector part 121. These plurality of sealing materials 123 are arranged with a predetermined gap in the X direction and the Y direction, respectively.

[0022] Here, in a conventional battery module, a long sealing material is continuously arranged at the peripheral part of the current collector part. That is, the conventional sealing material is formed in a rectangular frame shape in plan view, similar to the laminate sealing part 122. Also, in a conventional battery module, since such a long rectangular frame-shaped sealing material is welded using a long heater, the stress on the current collector part due to the shrinkage of the sealing material becomes large, and wrinkles occur in the current collector part.

[0023] Therefore, in the battery module 1 according to the embodiment, as shown in FIG. 2, the sealing material 123 is divided and arranged at the peripheral part of the current collector part 121. Thereby, it is possible to suppress the stress from being generated at once in the longitudinal direction (X direction, Y direction). That is, since the stress concentration on the current collector part 121 due to the sealing material 123 can be dispersed and relaxed, the occurrence of wrinkles in the current collector part 121 can be suppressed.

[0024] In addition, the laminate seal portion 122 is welded onto the current collector portion 121 shown in Figure 2 via the sealant 123, but the resin constituting the sealant 123 stretches during welding. As a result of this stretching of the resin, the gaps between the sealants 123 are filled, making the gaps smaller (or eliminating the gaps altogether). Thus, the sealant 123 only needs to be arranged discontinuously (with gaps) around the periphery of the current collector portion 121 at least before the laminate seal portion 122 is welded, and may be arranged continuously (without gaps) after the laminate seal portion 122 is welded.

[0025] Here, the method of discontinuously arranging the sealing material around the periphery of the current collector is not limited to the configuration shown in Figure 2. For example, as shown in Figure 3(a), the sealing material 124 may be arranged in a zigzag pattern around the periphery of the current collector 121.

[0026] The sealing material 124 has a first sealing portion 124a extending in the X direction and a second sealing portion 124b extending in the Y direction. Furthermore, in the X direction, only one of the first sealing portion 124a or the second sealing portion 124b is positioned. That is, the first sealing portion 124a and the second sealing portion 124b are not positioned adjacent to each other in the X direction.

[0027] Furthermore, in the Y direction, the first sealing portion 124a and the second sealing portion 124b are arranged alternately. That is, the first sealing portion 124a and the second sealing portion 124b are arranged adjacent to each other in the Y direction. In this way, the sealing material 124 is arranged discontinuously in a specific direction (in this case, the Y direction) of the periphery of the current collector portion 121, and a gap exists between the adjacent second sealing portion 124b.

[0028] When welding the current collector 121 and the laminate seal portion 122 with the sealing material 124, the welding is performed in two stages. In the first welding stage, the current collector 121 and the laminate seal portion 122 are welded at the outermost position of the periphery of the current collector 121, as shown in part A of Figure 3(b). In the second welding stage, the current collector 121 and the laminate seal portion 122 are welded at a position inward from part A, as shown in part B of Figure 3(c). Alternatively, the welding shown in Figure 3(c) may be performed in the first stage and the welding shown in Figure 3(c) may be performed in the second stage.

[0029] In this way, by arranging the sealing material 124 in a zigzag pattern around the periphery of the current collector 121 and welding the laminated seal portion 122 to it, stress concentration on the current collector 121 due to the sealing material 124 can be dispersed and mitigated. Furthermore, the adhesion between the current collector 121 and the laminated seal portion 122 can be further improved.

[0030] The method of discontinuously arranging the sealing material around the periphery of the current collector is not limited to the embodiments shown in Figures 2 and 3. For example, as shown in Figure 4, the sealing material 127 may be arranged discontinuously by pre-processing the current collector 125. As shown in Figure 4, when viewed from the side, the sealing material 127 is arranged discontinuously in a specific direction (here, the X direction), and a gap exists between adjacent sealing materials 127.

[0031] Multiple recesses 126 are formed on the upper surface of the peripheral edge of the current collector 125. When joining the current collector 125 and the laminate seal portion 122, first, as shown in Figure 4(b), sealant 127 is filled into the recesses 126. Next, as shown in Figure 4(c), sealant 128 is placed on the portion of the peripheral edge of the current collector 125 other than the recesses 126 and on top of the sealant 127, and the laminate seal portion 122 is placed on top of that and welded. The sealant 128, like the laminate seal portion 122, is formed in the shape of a rectangular frame when viewed from above.

[0032] By forming multiple recesses 126 on the surface of the current collector 125, placing a sealing material 127 in the recesses 126, and then placing another sealing material 128 on top of that to weld the laminated seal portion 122, stress due to differences in coefficients of thermal expansion can be localized. This disperses and mitigates stress concentration on the current collector 125 caused by the sealing materials 127 and 128. Furthermore, the adhesion between the current collector 125 and the laminated seal portion 122 can be further improved.

[0033] Further effects and modifications can be readily derived by those skilled in the art. Therefore, broader aspects of the present invention are not limited to the specific details and representative embodiments expressed and described above. Accordingly, various modifications are possible without departing from the spirit or scope of the overall concept of the invention as defined by the appended claims and their equivalents. [Explanation of Symbols]

[0034] 1 Battery Module 11. Stacked Energy Storage Modules 12 Exterior 121 Current collector 122 Laminate seal section 122a First resin layer 122b Metal layer 122c Second resin layer 123,124 Sealant 124a First seal section 124b Second seal section 125 Current collector 126 recess 127,128 sealing material

Claims

[Claim 1] It has an outer casing that houses a stack of energy storage modules, The exterior body is, A current collector unit that supplies power from the aforementioned energy storage module stack, A laminate seal portion that welds the aforementioned outer casings together, Equipped with, The current collection section and the laminated seal section are joined together by a sealing material. The sealing material is discontinuously arranged around the periphery of the current collector. Battery module.

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