Energy storage module

Abstract

To provide a sealing structure of an energy storage module capable of suppressing damage to an energy storage module in low-temperature conditions.SOLUTION: A sealing structure of an energy storage module (1) in an embodiment of the present disclosure is configured so that, in the energy storage module (1), an electrode (2) of the energy storage module (1) is sealed with a resin seal member (3). In the resin seal member (3), only a stress concentration area including an area located at the center of the edge forming the periphery of the energy storage module (1) viewing the energy storage module (1) from the thickness direction is made of a material that has high low-temperature strength compared to polypropylene.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a sealing structure for an electricity storage module. [Background technology]

[0002] In a typical energy storage module, the periphery of the electrode section is sealed with a resin sealing member such as a spacer. In this case, in the energy storage module of Patent Document 1, the seam of the resin sealing member is sealed with another resin sealing member to prevent leakage of the electrolyte from the seam. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-16904 Summary of the Invention [Problem to be solved by the invention]

[0004] The present applicant has discovered the following problem: When an impact is applied to an energy storage module under low-temperature conditions, stress is concentrated in a portion of the resin seal member that is located at the center of a side that forms the periphery of the energy storage module, when viewed from the thickness direction of the energy storage module.

[0005] Therefore, in a typical energy storage module, cracks may occur in the resin seal member at the center of the side that forms the periphery of the energy storage module, potentially damaging the energy storage module.

[0006] The present disclosure has been made in consideration of such problems, and provides a sealing structure for an electricity storage module that can suppress damage to the electricity storage module under low-temperature conditions. [Means for solving the problem]

[0007] A sealing structure for an electricity storage module according to one aspect of the present disclosure is a sealing structure for an electricity storage module, The storage module has an electrode portion sealed with a resin sealing member, The resin sealing member is formed of a material with higher low-temperature strength than polypropylene only in the stress concentration portion, which includes a portion located in the center of the edge that forms the peripheral portion of the storage module when viewed from the thickness direction of the storage module. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to realize a sealing structure for an electricity storage module that can suppress damage to the electricity storage module under low-temperature conditions. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view showing an electricity storage module according to an embodiment. [Figure 2] FIG. 2 is a cross-sectional view taken along line II-II of FIG. [Figure 3] 2 is a view of the energy storage module according to the embodiment as viewed from the positive side of the Z axis. FIG. [Figure 4] 2 is a view of the energy storage module according to the embodiment as viewed from the positive side of the X axis. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Specific embodiments to which the present disclosure is applied will be described in detail below with reference to the drawings. However, the present disclosure is not limited to the following embodiments. In addition, for clarity of explanation, a three-dimensional (XYZ) coordinate system is used, and the following description and drawings are appropriately simplified.

[0011] Fig. 1 is a perspective view showing the energy storage module of the present embodiment. Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. Fig. 3 is a view of the energy storage module of the present embodiment seen from the +Z-axis side. Fig. 4 is a view of the energy storage module of the present embodiment seen from the +X-axis side.

[0012] The sealing structure of the power storage module 1 of this embodiment is suitable as a sealing structure for a power storage module used in batteries of various vehicles such as hybrid cars and electric cars. The power storage module 1 is, for example, a secondary battery such as a nickel-metal hydride secondary battery or a lithium-ion secondary battery. However, the power storage module 1 may also be an electric double layer capacitor or an all-solid-state battery.

[0013] In this embodiment, the energy storage module 1 is configured as a lithium ion secondary battery. As shown in FIGS. 1 to 3 , the energy storage module 1 includes an electrode unit 2 and a resin sealing member 3, and has, for example, a substantially rectangular shape when viewed from the Z-axis direction. As shown in FIG. 2 , the electrode unit 2 includes a plurality of energy storage cells 20 stacked in the Z-axis direction, and has, for example, a substantially rectangular shape when viewed from the Z-axis direction. The energy storage cell 20 includes a positive electrode 21, a negative electrode 22, and a separator 23.

[0014] As shown in Fig. 2, the positive electrode 21 includes a positive electrode active material layer 21a and a current collector 21b. The negative electrode 22 includes a negative electrode active material layer 22a and a current collector 22b. In Fig. 2, the current collector 21b of the positive electrode 21 and the current collector 22b of the negative electrode 22 are shown as a simplified integrated structure.

[0015] The separator 23 is disposed between the positive electrode active material layer 21a of the positive electrode 21 and the negative electrode active material layer 22a of the negative electrode 22, and prevents short-circuiting between the positive electrode 21 and the negative electrode 22. Here, the configuration of the electrode part 2 is substantially the same as that of a general electrode part, and is not an essential part of the invention, so a detailed description thereof will be omitted.

[0016] 2, the resin sealing member 3 maintains a gap between the current collector 21b of the positive electrode 21 and the current collector 22b of the negative electrode 22. The resin sealing member 3 is disposed so as to surround the electrode portion 2 when viewed from the Z-axis direction, and holds an end of the current collector 21b of the positive electrode 21, an end of the current collector 22b of the negative electrode 22, and an end of the separator 23. At this time, an electrolyte solution is contained in spaces S between the resin sealing member 3 and the positive electrode active material layer 21a of the positive electrode 21, and between the resin sealing member 3 and the negative electrode active material layer 22a of the negative electrode 22.

[0017] 1 and 3, the resin sealing member 3 includes a first portion 31 and a second portion 32. When viewed from the Z-axis direction, the first portion 31 includes a central portion 31a that is located approximately in the center of the side of the energy storage module 1 that extends in the X-axis direction and in the center of the side that extends in the Y-axis direction, and end portions 31b that are located at both ends of the side of the energy storage module 1 that extends in the X-axis direction and in the Y-axis direction.

[0018] The central portion 31a and the end portions 31b are stress concentration portions where stress is concentrated on the resin sealing member 3 when the energy storage module 1 is in a low-temperature state. For example, when the energy storage module 1 is in a low-temperature state, vibration or impact to the energy storage module 1 causes the energy storage module 1 to deform, causing the resin sealing member 3 to bend and deform, resulting in stress concentration on the central portion 31a.

[0019] Furthermore, when the resin sealing member 3 shrinks under low temperature conditions of the energy storage module 1, the deformation of the resin sealing member 3 on the negative Z-axis side is blocked by the lower plate (not shown) covering the end of the energy storage module 1 on the negative Z-axis side, causing the four corners of the resin sealing member 3 to deform and warp toward the positive Z-axis side, with stress concentrating on the end portion 31b which serves as the fulcrum.

[0020] Therefore, in this embodiment, the central portion 31a and the end portions 31b are made of a material that has higher low-temperature strength than polypropylene, which is generally used to make the resin sealing member 3. In this case, the material with high low-temperature strength is preferably a material with a brittle temperature of −40° C. or lower, such as polyethylene, polyvinylidene fluoride, or perfluoroalkoxyalkane.

[0021] Here, when the resin sealing member 3 and the fixed member fixed to the resin sealing member 3 are deformed under low temperature conditions of the energy storage module 1, stress is also concentrated around the fixed member in the resin sealing member 3. Therefore, although not shown in the figure, it is preferable that the first part 31, which is made of a material with high low-temperature strength, is also arranged on both sides of the fixed member when viewed from the Z-axis direction.

[0022] The second portion 32 is the other portion of the resin seal member 3 than the first portion 31. The second portion 32 can be made of an inexpensive material, such as polypropylene, as opposed to a material with high low-temperature strength.

[0023] As described above, in the sealing structure of the energy storage module 1 of the present embodiment, only the first portion 31, where stress concentrates in the resin sealing member 3 under low-temperature conditions, of the energy storage module 1 is formed from a material with high low-temperature strength. This prevents damage to the energy storage module 1 under low-temperature conditions, and allows the sealing structure of the energy storage module 1 to be configured inexpensively.

[0024] Although the first portion 31 of the resin sealing member 3 of this embodiment includes a central portion 31a and an end portion 31b, it is sufficient that the first portion 31 includes at least the central portion 31a. Furthermore, although the energy storage module 1 of this embodiment has a substantially rectangular shape, it may have another polygonal shape, and the shape of the energy storage module 1 is not limited.

[0025] The present disclosure is not limited to the above-described embodiments, and can be modified as appropriate within the scope of the present disclosure. [Explanation of symbols]

[0026] 1. Energy storage module 2 Electrode part 20 Energy storage cells 21 positive electrode, 21a positive electrode active material layer, 21b current collector 22 negative electrode, 22a negative electrode active material layer, 22b current collector 23 Separator 3 Resin sealing material 31 first portion, 31a central portion, 31b end portion 32 Second Part S space

Claims

1. The electrode portion of the energy storage module is sealed with a resin sealing member, The resin sealing member is formed of a material with a brittle temperature of -40°C or lower only in stress concentration portions including a portion located at the center of an edge forming the peripheral portion of the energy storage module and a portion located at an end of an edge forming the peripheral portion of the energy storage module when viewed from the thickness direction of the energy storage module.

2. a fixed member is fixed to the resin seal member, 2. The energy storage module according to claim 1, wherein the resin sealing member is formed of a material having a brittle temperature of −40° C. or lower at portions on both sides of the fixed member when viewed in a thickness direction of the energy storage module.

3. The energy storage module according to claim 1 or 2, wherein the material having a brittle temperature of −40° C. or less is polyethylene, polyvinylidene fluoride, or perfluoroalkoxyalkane.

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