Method of manufacturing battery stack

Abstract

To provide a method of manufacturing a battery stack that suppresses the variation in intervals between battery cells in a lamination direction.SOLUTION: A method of manufacturing a battery stack including a plurality of battery cells and a plurality of spacers that are alternately laminated in a lamination direction, includes: a lamination process of alternately arranging and laminating battery cells and spacers; and a compression process of compressing a laminate formed of the laminated battery cells and spacers by using a movable jig in a lamination direction. The spacers includes first spacers with a thicker thinness and second spacers with a thickness thinner than that of the first spacer. In the lamination process, the battery cells and spacers are alternately laminated by arranging the first spacers on a closer side from the movable jig of the battery cells in the compression process and the second spacers on a distant side from the movable jig thereof in the compression process.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a battery stack.

Background Art

[0002] Patent Document 1 discloses that by providing a shim between a battery stack in which battery cells and resin spacers are alternately laminated and a housing case, variations in the pressing force for pressing the battery stack are suppressed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the spacer is made of an elastic material as in the configuration described in Patent Document 1, when the battery stack is pressed in the stacking direction, the spacer itself elastically deforms and compresses, so that variations occur in the intervals between the battery cells. If variations occur in the intervals between the battery cells in the stacking direction, there is a risk of connection failure such that the cells cannot be connected by a fixed-size bus bar when connecting the bus bar to the battery cells.

[0005] The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for manufacturing a battery stack capable of suppressing variations in the intervals between battery cells in the stacking direction.

Means for Solving the Problems

[0006] The present invention is a method for manufacturing a battery stack including a laminate in which a plurality of battery cells and a plurality of spacers are alternately arranged in a stacking direction, the method including: a stacking step of alternately arranging and stacking the battery cells and the spacers; and a compression step of compressing a laminate composed of the stacked battery cells and spacers in the stacking direction using a movable jig. The spacer includes a first spacer having a large thickness and a second spacer having a smaller thickness than the first spacer. In the stacking step, the first spacer is arranged closer to the movable jig in the compression step, and the second spacer is arranged farther from the movable jig in the compression step, and the battery cells and the spacers are alternately stacked.

Effects of the Invention

[0007] In the present invention, it is possible to suppress variations in the intervals between battery cells in the stacking direction.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0009] Hereinafter, a method for manufacturing a battery stack in an embodiment of the present invention will be specifically described. Note that the present invention is not limited to the embodiments described below.

[0010] FIG. 1 is a diagram for explaining a method of manufacturing a battery stack according to an embodiment. The battery stack 1 includes a laminate 10 in which a plurality of battery cells 2 and a plurality of spacers 3 are alternately arranged in the stacking direction. A battery pack including the battery stack 1 is mounted on an electric vehicle. The battery pack mounted on the electric vehicle supplies power to a motor for driving. Particularly in a battery electric vehicle (BEV), since the cruising range is important, it is necessary to aim at improving the energy density of the battery pack. Therefore, in the process of manufacturing the battery stack 1, it is conceivable to include a process of laminating the battery cell 2 and the spacer 3 and accommodating them while applying pressure to a lower case. However, when pressure is applied, variations occur in the amount of shrinkage of the battery cell and the amount of shrinkage of the spacer, and the pitch between the battery cells in the laminate varies. This is due to the difference in the compressibility (compression rate) between the battery cell and the spacer, and the fact that the laminate on the side where pressure is applied by the equipment is more likely to collapse. If the pitch between the battery cells in the laminate varies, the battery cells cannot be connected by a fixed-size bus bar. In addition, there is a time difference until the entire laminate becomes uniform after applying pressure by the equipment. Therefore, in some cases, creep occurs over time after pressurization, and product damage gradually occurs in the market. Therefore, the method of manufacturing the battery stack 1 according to the embodiment is configured to reduce the variation in the pitch between the battery cells 2 in the laminate 10.

[0011] The method of manufacturing the battery stack 1 includes a stacking step of arranging the members constituting the laminate 10 and a compression step of compressing the laminate 10 in the stacking direction.

[0012] The stacking step is a step of alternately arranging and stacking the battery cell 2 and the spacer 3 in the stacking direction. In the stacking step, the laminate 10 is formed. The laminate 10 includes a battery cell 2, a spacer 3, an end plate 4, and a pitch adjustment shim 5.

[0013] The battery cell 2 includes a first battery cell 2A with a greater thickness and a second battery cell 2B with a thickness thinner than that of the first battery cell 2A. The first battery cell 2A is formed to be thicker than the second battery cell 2B by changing the member design, such as increasing the thickness of the members constituting the interior of the cell or increasing the thickness of the can case (cell case). Alternatively, since the cell thickness varies with individual differences when manufacturing the battery cell 2, it is also possible to classify and use thick battery cells 2 and thin battery cells 2. In this description, when the first battery cell 2A and the second battery cell 2B are not particularly distinguished, they are referred to as the battery cell 2.

[0014] The spacer 3 is an elastic heat insulating material. The spacer 3 is used in combination with materials such as Si rubber, EPDM, foamed materials, silica-based heat insulating materials, and thermally flexible elastomers. The spacer 3 includes a first spacer 3A with a greater thickness and a second spacer 3B with a thickness thinner than that of the first spacer 3A. When the first spacer 3A and the second spacer 3B are not particularly distinguished, they are referred to as the spacer 3.

[0015] The end plates 4 are a pair of plates arranged on both sides of the laminate 10 in the stacking direction.

[0016] The pitch adjustment shim 5 is a shim for adjusting the pitch between the battery cells 2 of the laminate 10. The pitch adjustment shim 5 is arranged at a position sandwiched between the battery cell 2 and the spacer 3 or at a position sandwiched between the spacer 3 and the end plate 4.

[0017] In the stacking process, thick members (first battery cell 2A, first spacer 3A) are arranged on the equipment pressurizing side in the compression process. In the stacking process, the first battery cell 2A, the first spacer 3A, and the pitch adjustment shim 5 are arranged so that many of them are sandwiched on the equipment pressurizing side. As shown in FIG. 1, when one-sided pressurization is performed in the compression process, in the stacking process, the first battery cell 2A, the first spacer 3A, and the pitch adjustment shim 5 are arranged in large numbers on the equipment pressurizing side, which is one side in the stacking direction. For example, in the case of a stacked body 10 in which 50 battery cells 2 and spacers 3 are sandwiched between them, numbering is performed from the one end side in the stacking direction to the 1st to 50th cells. If the side pressurized by the equipment is one side of the 1st cell, thick members (first battery cell 2A, first spacer 3A) and pitch adjustment shims 5 are arranged in large numbers on the 1st to 25th cell side. In the stacking process, the first battery cell 2A and the first spacer 3A, which are thick members, are arranged with a bias in the stacking direction.

[0018] The compression process is a process of pressurizing the stacked body 10 so that the stacked body 10 is compressed in the stacking direction in a state where a plurality of battery cells 2 and a plurality of spacers 3 are alternately stacked. In the compression process, it is possible to use, for example, a movable jig when pressurizing with equipment. In the compression process, the stacked body 10 composed of the battery cells 2 and the spacers 3 stacked by the stacking process is compressed in the stacking direction using a movable jig. The equipment pressurizing side is synonymous with the side close to the movable jig. As shown in FIG. 1, in the compression process, when one-sided pressurization is performed, the thick members arranged on the side close to the movable jig receive a large amount of the pressurization load.

[0019] As described above, according to the embodiment, the variation in the pitch between the battery cells 2 can be reduced immediately after equipment pressurization. Thereby, connection failures can be suppressed in the connection process of connecting between the battery cells 2 in the next process, and the defect rate is reduced. In addition, since the amount of creep after the battery stack 1 is released to the market is small, an optimal bus bar design that minimizes market stress becomes possible.

[0020] Note that the battery stack 1 may not be provided with the pitch adjustment shim 5. The battery stack 1 only needs to have thick members (first battery cell 2A, first spacer 3A) arranged with a bias.

[0021] Moreover, for the battery stack 1, it is only necessary that many first spacers 3A are arranged on the equipment pressurization side, and the first battery cells 2A do not necessarily have to be arranged. For example, the thick member is the first spacer 3A, many first spacers 3A are arranged on the equipment pressurization side, and all of the plurality of battery cells 2 may be constituted by the second battery cells 2B. The second battery cell 2B is a battery cell of normal thickness, and the first battery cell 2A is a battery cell formed thicker than the normal thickness.

[0022] Moreover, the pressurization process is not limited to single-sided pressurization, and double-sided pressurization may also be possible. As shown in FIG. 2, when double-sided pressurization is performed in the compression process, for example, in the laminate 10 sandwiching 50 battery cells 2 and spacers 3 therebetween, numbering is performed from one end side in the stacking direction for the 1st to 50th cells. In this case, if the sides pressurized by the equipment are both sides of the 1st cell and the 50th cell, many thick members (first battery cells 2A, first spacers 3A) and pitch adjustment shims 5 are arranged on the 1st to 16th cell side and the 34th to 50th cell side.

Explanation of Reference Numerals

[0023] 1 Battery stack 2 Battery cell 2A First battery cell 2B Second battery cell 3 Spacer 3A First spacer 3B Second spacer 4 End plate 10 Laminate

Claims

【Claim 1】 A method for manufacturing a battery stack including a laminate in which a plurality of battery cells and a plurality of spacers are alternately arranged in a stacking direction, a stacking step of alternately arranging and stacking the battery cells and the spacers, a compression step of compressing the laminate composed of the stacked battery cells and spacers in the stacking direction using a movable jig, and the spacer includes a first spacer having a large thickness, a second spacer having a thickness smaller than that of the first spacer, and in the stacking step, the first spacer is arranged on the side closer to the movable jig in the compression step, and the second spacer is arranged on the side farther from the movable jig in the compression step to alternately stack the battery cells and the spacers A method for manufacturing a battery stack, characterized in that.

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