Battery module

Abstract

To provide a battery module in which degradation of secondary batteries can be detected with a relatively simple structure.SOLUTION: A battery module 1 comprises a pair of secondary batteries 10 and a spacer 20. Each of the secondary batteries 10 includes an electrode and a case 12. The spacer 20 has a central spacer part 22 and an outer spacer part 24. The central spacer part 22 makes contact with the case 12 when the temperature of the case 12 is lower than a specified temperature. The outer spacer part 24 makes contact with the case 12 when the temperature of the case 12 is lower than the specified temperature, and when the temperature of the case 12 is equal to or higher than the specified temperature, it expands such that a space S may be formed between the case 12 and the central spacer part 22.SELECTED DRAWING: Figure 4

Description

Technical Field

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

Background Art

[0002] Conventionally, a battery module including a plurality of secondary batteries is known. For example, International Publication No. 2019 / 155713 discloses a power supply device including a battery laminate formed by laminating a plurality of battery cells and a separator disposed between the battery cells. The separator has a resin frame and a heat insulating base material provided in the resin frame. The heat insulating base material has flexibility to be deformed by being pressed against the expanding laminated surface of the battery cell.

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 described in International Publication No. 2019 / 155713, when one secondary battery generates heat, there is room for improvement in suppressing the transfer of heat from this secondary battery to the secondary battery adjacent thereto (so-called heat chain).

[0005] An object of the present disclosure is to provide a battery module capable of suppressing heat transfer between secondary batteries.

Means for Solving the Problems

[0006] A battery module according to an aspect of the present disclosure includes a pair of secondary batteries arranged adjacent to each other, and a spacer arranged between the pair of secondary batteries. Each secondary battery of the pair of secondary batteries includes an electrode and a case that houses the electrode. The spacer has a central spacer portion arranged between central portions of the respective cases, and an outer spacer portion arranged between the respective cases and around the central spacer portion. The central spacer portion is in contact with each case when the temperature of the case is less than a specified temperature. The outer spacer portion is in contact with each case when the temperature of the case is less than the specified temperature, and expands so that a space is formed between each case and the central spacer portion when the temperature of the case is greater than or equal to the specified temperature.

[0007] Further, it is preferable that the outer spacer portion is formed in an annular shape so as to surround the central spacer portion.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0009] Embodiments of the present disclosure will be described with reference to the drawings. In the drawings referred to below, the same or corresponding members are denoted by the same reference numerals.

[0010] FIG. 1 is a perspective view schematically showing the configuration of a battery module according to an embodiment of the present disclosure. This battery module 1 is mounted on a vehicle, for example. Note that the mounting posture of this battery module 1 on the vehicle is not limited.

[0011] As shown in FIG. 1, the battery module 1 includes a pair of secondary batteries 10 and a spacer 20. Note that the numbers of the secondary batteries 10 and the spacer 20 are not particularly limited.

[0012] The pair of secondary batteries 10 are arranged to face each other. Examples of each secondary battery 10 include a lithium ion battery. Each secondary battery 10 has a case 12 and a pair of external terminals 14.

[0013] The case 12 houses electrodes and the like (not shown). The case 12 is formed in a rectangular parallelepiped shape. The case 12 is formed flat. That is, the case 12 has two first side surfaces having a relatively large area and two second side surfaces having an area smaller than that of the first side surface. The pair of secondary batteries 10 are arranged such that the first side surfaces of the respective cases 12 face each other. Hereinafter, the mutually facing first side surfaces are referred to as "opposing surfaces 12a". Each opposing surface 12a is formed flat.

[0014] Each external terminal 14 protrudes from the outer surface (the upper surface in the present embodiment) of the case 12. One of the pair of external terminals 14 is a positive electrode terminal, and the other is a negative electrode terminal.

[0015] The spacer 20 is disposed between the pair of secondary batteries 10. More specifically, the spacer 20 is disposed between the opposing surfaces 12a of the respective cases 12. As shown in FIGS. 2 and 3, the spacer 20 has a central spacer portion 22 and an outer spacer portion 24.

[0016] The central spacer portion 22 is disposed between the central portions of the opposing surfaces 12a of each case 12. The central spacer portion 22 is formed in a rectangular shape. However, the shape of the central spacer portion 22 is not limited to a rectangular shape. The central spacer portion 22 is made of polypropylene, rubber, or the like. As shown in FIG. 2, the central spacer portion 22 is in contact with the opposing surfaces 12a of each case 12 when the temperature of the case 12 is less than the specified temperature. The central spacer portion 22 may be formed of a material that melts when the temperature of the case 12 is equal to or higher than the specified temperature.

[0017] The outer spacer portion 24 is disposed between each case 12 and around the central spacer portion 22. In the present embodiment, the outer spacer portion 24 is formed in an annular shape surrounding the central spacer portion 22. As shown in FIG. 2, the outer spacer portion 24 is in contact with the opposing surfaces 12a of each case 12 when the temperature of the case 12 is less than the specified temperature. The outer spacer portion 24 is made of a material (such as expanded graphite) that expands at a temperature equal to or higher than the specified temperature. The outer spacer portion 24 is made of a material having a coefficient of thermal expansion at a temperature equal to or higher than the specified temperature that is greater than that of the central spacer portion 22.

[0018] FIG. 4 is a cross-sectional view schematically showing a state in which the temperature of the case 12 of the secondary battery 10 is equal to or higher than the specified temperature. As shown in this FIG. 4, the outer spacer portion 24 expands so that a space S is formed between the opposing surfaces 12a of each case 12 and the central spacer portion 22 when the temperature of the case 12 is equal to or higher than the specified temperature. At this time, the central spacer portion 22 may melt.

[0019] As described above, in the battery module 1 of the present embodiment, when the specific secondary battery 10 generates heat so that the temperature of the case 12 of the specific secondary battery 10 becomes equal to or higher than the specified temperature, a space S is formed between the opposing surfaces 12a, so that heat transfer from the specific secondary battery 10 to the secondary battery 10 adjacent to the specific secondary battery 10 is suppressed.

[0020] Further, in this battery module 1, when the temperature of the case 12 is lower than the specified temperature, since the central spacer portion 22 and the outer spacer portion 24 are in contact with the cases 12 of both of the pair of secondary batteries 10, expansion of each case 12 during charge and discharge of the secondary battery 10 is effectively suppressed.

[0021] In addition, in the above-described embodiment, as shown in FIG. 5, the outer spacer portion 24 may be disposed at the four corners of the periphery of the central spacer portion 22.

[0022] It is understood by those skilled in the art that the above-described exemplary embodiments are specific examples of the following aspects.

[0023] The battery module in the above-described embodiment includes a pair of secondary batteries arranged adjacent to each other, and a spacer disposed between the pair of secondary batteries. Each secondary battery of the pair of secondary batteries includes an electrode and a case that houses the electrode. The spacer has a central spacer portion disposed between the central portions of each case, and an outer spacer portion disposed between the cases and around the central spacer portion. The central spacer portion is in contact with each case when the temperature of the case is lower than the specified temperature. The outer spacer portion is in contact with each case when the temperature of the case is lower than the specified temperature, and expands so that a space is formed between each case and the central spacer portion when the temperature of the case is equal to or higher than the specified temperature.

[0024] Further, it is preferable that the outer spacer portion is formed in an annular shape so as to surround the central spacer portion.

[0025] It should be considered that all the embodiments disclosed this time are illustrative in all respects and not restrictive. The scope of the present invention is shown not by the description of the above-described embodiments but by the claims, and further includes all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0026] 1 Battery module, 10 Secondary battery, 12 Case, 12a Opposing surface, 14 External terminal, 20 Spacer, 22 Central spacer portion, 24 Outer spacer portion, S Space.

Claims

【Claim 1】 A pair of secondary batteries arranged adjacent to each other, and a spacer disposed between the pair of secondary batteries, wherein each of the pair of secondary batteries includes an electrode and a case housing the electrode, and a pair of external terminals provided on an upper surface of the case, the pair of external terminals being spaced apart from each other in a width direction orthogonal to both a direction in which the pair of secondary batteries face each other and a vertical direction, the spacer including a central spacer portion disposed between central portions of the respective cases, and an outer spacer portion disposed between the respective cases and around the central spacer portion, a dimension of the central spacer portion in the width direction being larger than a length between outer surfaces of the pair of external terminals in the width direction, the outer spacer portion being continuously connected in an annular shape so as to surround the central spacer portion, the central spacer portion being made of a material that contacts each case when a temperature of the case is less than a specified temperature and melts when the temperature of the case is equal to or higher than the specified temperature, the outer spacer portion contacting each case when the temperature of the case is less than the specified temperature and expanding so that a space is formed between each case and the central spacer portion when the temperature of the case is equal to or higher than the specified temperature, a battery module.

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