Battery pack

Abstract

To provide a battery pack capable of suppressing deterioration in performance of a battery cell when the battery cell expands.SOLUTION: A battery pack according to the present invention includes a battery module in which a plurality of battery cells are stacked, and a plurality of restraining bands that restrain the plurality of battery cells when an inward restraining load acts on the battery module, and at least one of the plurality of restraining bands is provided with a weak portion that breaks when a load above a certain level is applied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Patent document 1 discloses a battery pack having a restraint band that restrains multiple battery cells in a state where an inward restraint load acts in the stacking direction of the multiple battery cells on a battery module in which the multiple battery cells are stacked. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-072168 Summary of the Invention [Problem to be solved by the invention]

[0004] In the battery pack disclosed in Patent Document 1, when the battery cells deteriorate and expand, it is difficult to release the restraining load, which may lead to deterioration of the performance of the battery cells.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its object is to provide a battery pack that can suppress performance degradation of battery cells when the battery cells expand. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the objectives, the battery pack of the present invention is a battery pack comprising a battery module in which a plurality of battery cells are stacked, and a plurality of restraint bands that restrain the plurality of battery cells in a state in which an inward restraint load acts on the battery module in the stacking direction of the plurality of battery cells, and is characterized in that at least one of the plurality of restraint bands is provided with a fragile portion that breaks when a load above a certain level is applied. [Effects of the Invention]

[0007] The battery pack according to the present invention has the advantage that when the battery cell expands, the weak parts of the restraining bands break, thereby reducing the restraining load and suppressing deterioration in the performance of the battery cell. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a battery pack according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the state of the battery pack when the battery cell expands. [Figure 3] FIG. 3 is a diagram showing the state of the battery pack when the weak portion of the first restraint band breaks. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, an embodiment of a battery pack according to the present invention will be described, but the present invention is not limited to the embodiment.

[0010] 1 is a diagram showing a schematic configuration of a battery pack 1 according to an embodiment. The battery pack 1 according to the embodiment is, for example, a power storage device mounted on an electric vehicle, and is a power supply source that supplies power to a motor that is a drive source of the electric vehicle. The battery pack 1 according to the embodiment includes a battery module 2, a pair of end plates 31, 32 (a first end plate 31 and a second end plate 32), a plurality of restraint bands 41, 42 (a first restraint band 41 and a second restraint band 42), a strain gauge 5, and a breakage detection device 6.

[0011] The battery module 2 is configured as a stack of multiple battery cells 20. A first end plate 31 and a second end plate 32 are provided at both ends of the battery module 2 in the stacking direction of the multiple battery cells 20, sandwiching the multiple battery cells 20. The first end plate 31 and the second end plate 32 have a plate-like shape and are made of, for example, metal. The first restraint bands 41 and the second restraint bands 42 are arranged side by side at intervals in the height direction of the battery pack 1 along the side surfaces of the battery module 2, and connect and restrain the first end plate 31 and the second end plate 32 with the multiple battery cells 20 (battery module 2) sandwiched between them. As a result, the first restraint bands 41 and the second restraint bands 42 restrain the multiple battery cells 20 with an inward restraint load acting on the battery module 2 (multiple battery cells 20) in the stacking direction. The material for the first restraint band 41 and the second restraint band 42 can be, for example, a metal such as stainless steel that will not rust in the environment in which the battery pack 1 is installed, or a resin that will not deteriorate in the environment in which the battery pack 1 is installed.

[0012] The first restraint bands 41 are provided with weakened portions 410 that break when a load equal to or greater than a certain level is applied. By providing the weakened portions 410 in the first restraint bands 41, the location at which the first restraint bands 41 break can be controlled. The weakened portions 410 of the first restraint bands 41 can be provided, for example, by making the cross-sectional area of ​​the first restraint bands 41 smaller than the restrained portions 410. The weakened portions 410 of the first restraint bands 41 are provided with strain gauges 5, which are conductive sensors that can detect breakage of the first restraint bands 41 (weak portions 410). The breakage detection device 6 can detect breakage of the first restraint bands 41 (weak portions 410) when the strain gauges 5 provided in the weakened portions 410 of the first restraint bands 41 break and detect a break in the wire.

[0013] In the battery pack 1 according to the embodiment, it is sufficient that there are two or more restraining bands that restrain the plurality of battery cells 20, and it is sufficient that there is at least one or more restraining bands that are provided with a fragile portion.

[0014] Fig. 2 is a diagram showing the state of the battery pack 1 when the battery cell 20 expands. Fig. 3 is a diagram showing the state of the battery pack 1 when the fragile portion 410 of the first restraint band 41 breaks.

[0015] In the battery pack 1 according to the embodiment, when at least one battery cell 20 among the plurality of battery cells 20 expands due to deterioration or the like, the load acting on the first end plate 31 and the second end plate 32 in the stacking direction of the plurality of battery cells 20 increases, as shown in FIG. 2 . This increases the restraint load acting inward in the stacking direction on the plurality of battery cells 20 (battery module 2) by the first restraint bands 41 and the second restraint bands 42, and increases the mechanical load (load) acting on the first restraint bands 41 and the second restraint bands 42. When a load exceeding a certain level is applied to the first restraint band 41, the fragile portion 410 breaks, as shown in FIG. 3 . As a result, the plurality of battery cells 20 are restrained only by the second restraint bands 42, and the restraint load acting inward in the stacking direction on the plurality of battery cells 20 (battery module 2) decreases.

[0016] In the battery pack 1 according to the embodiment, when the battery cells 20 expand in the stacking direction due to deterioration or the like, the fragile portions 410 of the first restraint bands 41 break, thereby allowing the expansion of the battery cells 20 to be appropriately released. As a result, in the battery pack 1 according to the embodiment, the application of an excessive load to the battery cells 20 can be suppressed, and the load applied to the battery cells 20 can be kept within a certain range, thereby suppressing a decrease in performance due to a decrease in the circulation of electrolyte inside the battery cells 20.

[0017] Furthermore, in the battery pack 1 according to the embodiment, deterioration of the battery cells 20 can be detected by detecting information regarding which of the multiple restraint bands 41, 42 is functioning (which is restraining the multiple battery cells 20). As a method for detecting deterioration of the battery cells 20, for example, the breakage detection device 6 detects whether the strain gauge 5 provided in the weak portion 410 of the first restraint band 41 has broken and become disconnected, and deterioration diagnosis can be performed to detect whether the battery cells 20 have deteriorated based on whether both the first restraint band 41 and the second restraint band 42 are functioning or whether only the second restraint band 42 is functioning. [Explanation of symbols]

[0018] 1 battery pack 2 Battery Module 5 Strain gauges 6 Breakage detection device 20 battery cells 31 First end plate 32 Second end plate 41 First Restraint Band 42 Second Restraint Band 410 Weak part

Claims

[Claim 1] a battery module in which a plurality of battery cells are stacked; a plurality of restraint bands that restrain the plurality of battery cells in a state in which an inward restraint load acts on the battery module in a stacking direction of the plurality of battery cells; A battery pack comprising: The battery pack is characterized in that at least one of the plurality of restraining bands is provided with a weak portion that breaks when a load of a certain level or more is applied thereto.

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