Battery pack manufacturing method

Abstract

To provide a battery pack manufacturing method that can eliminate poor contact between components and thermal conductive materials without adding any manufacturing steps. [Solution] A method for manufacturing a battery pack comprising a battery module in which multiple battery cells are stacked, comprising: a coating step of applying a thermal conductive material to a lower case such that the coating trajectory of the thermal conductive material forms a pushback pattern shape; and an installation step of installing a battery module inside the lower case by pressing the thermal conductive material applied in a pushback pattern shape.

Description

Technical Field

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

Background Art

[0002] Patent Document 1 discloses that in a method for manufacturing a battery pack, the presence or absence of undulations of components is inspected every time, and a heat conductive material different from the normal process is applied and cured so as to match the undulations on the component side to ensure surface accuracy, and then the heat conductive material of the normal process is applied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the configuration described in Patent Document 1, it is possible to eliminate the contact failure between the component and the heat conductive material caused by the component shape. However, in the configuration described in Patent Document 1, when the number of components increases, it is necessary to deal with undulations each time, so the manufacturing process becomes numerous.

[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 pack that can eliminate the contact failure between the component and the heat conductive material without adding a manufacturing process.

Means for Solving the Problems

[0006] The present invention relates to a method for manufacturing a battery pack comprising a battery module in which a plurality of battery cells are stacked, and is characterized by including a coating step of applying a thermal conductive material to a lower case such that the coating trajectory of the thermal conductive material forms a pushback pattern shape, and an installation step of installing the battery module inside the lower case by pressing the thermal conductive material applied in the pushback pattern shape. [Effects of the Invention]

[0007] This invention makes it possible to eliminate poor contact between components and thermal conductive materials without adding any manufacturing steps. [Brief explanation of the drawing]

[0008] [Figure 1] This is a diagram illustrating the coating process included in the manufacturing method of a battery pack in an embodiment. [Figure 2] This diagram illustrates the airflow when a heat conductive material is pressed against something. [Figure 3] This figure shows the shape of the thermal conductive material applied during the coating process. [Figure 4] This figure shows the shape of the heat conductive material after it has been compressed and expanded during the installation process. [Modes for carrying out the invention]

[0009] The following describes in detail the method for manufacturing a battery pack according to embodiments of the present invention. However, the present invention is not limited to the embodiments described below.

[0010] The manufacturing method for the battery pack in this embodiment is a method for manufacturing a battery pack to be installed in an electric vehicle. When installed in an electric vehicle, the battery pack supplies power to the vehicle's drive motor. The battery pack comprises a plurality of battery modules, a case that houses the plurality of battery modules, and a cooler that cools the battery modules.

[0011] A battery module is a battery pack consisting of multiple battery cells stacked on top of each other. The case houses the battery module. Multiple battery modules are housed inside the case. The case comprises an upper cover and a lower case. The upper cover and lower case are fastened together by fastening members. The lower case has a bottom and side walls. Multiple modules are installed inside the case, at the bottom of the lower case. A cooler is used to cool the battery cells. The cooler is located outside the case. The cooler is positioned below the case and attached to the bottom of the lower case. The cooler cools the battery cells from outside the case, through the bottom of the lower case.

[0012] In the battery pack, thermal conductive material is provided on both sides of the bottom of the lower case. The thermal conductive material includes thermal conductive material provided inside the lower case between the inner surface of the bottom of the lower case and the bottom surface of the battery module, and thermal conductive material provided outside the lower case between the outer surface of the bottom of the lower case and the top surface of the cooler. Thermal conductive material is included in the heat transfer path from the cooler to the battery cells. During the manufacture of the battery pack, thermal conductive material is applied to the bottom of the lower case. The thermal conductive material applied to the inner surface of the bottom of the lower case is compressed by the battery module, and the thermal conductive material applied to the outer surface of the bottom of the lower case is compressed by the cooler.

[0013] As the battery capacity of a battery pack increases, the amount of heat generated by the battery also increases, so it is desirable to improve the cooling performance as a heat countermeasure. To achieve this, it is necessary to increase the contact area between the components and the heat conductive material applied between the various components. However, since the heat conductive material is compressed by the components during the manufacturing of the battery pack, if the heat conductive material is applied to satisfy the target thickness and target area at the application stage, there may be cases where the component does not come into contact with the heat conductive material depending on the shape of the component. Therefore, in this embodiment, the application trajectory of the heat conductive material is made into a push-back pattern shape, so that even if air remains during compression, air entrapment is eliminated, and the heat conductive material can be compressed to a thickness and area that is independent of the shape of the component.

[0014] The manufacturing method of the battery pack in the embodiment includes a coating step of applying a thermal conductive material to a case that houses an energy storage module, and an installation step of installing the battery module inside the case by compressing the thermal conductive material.

[0015] The coating process involves applying the thermal conductive material 2 to the bottom 1a of the lower case 1, as shown in Figure 1. The coating process includes applying the thermal conductive material 2 to the inner surface of the bottom 1a of the lower case 1 such that the coating trajectory of the thermal conductive material 2 forms a pushback pattern. In the coating process, the coating pattern of the thermal conductive material 2 is a repeating jagged pattern. The angle of the jagged trajectory is preferably 10 to 45 degrees.

[0016] The installation process involves installing the battery module on the bottom 1a of the lower case 1 by pressing down on the heat conductive material 2, which is applied in a push-back pattern shape. The installation process includes crushing the heat conductive material 2 with the battery module so that it is sandwiched between the lower surface of the battery module and the inner surface of the bottom 1a.

[0017] If air is trapped during pressing, it can result in areas of non-contact between the component and the thermal conductive material 2, leading to a decrease in quality. In this embodiment, by making the application trajectory of the thermal conductive material 2 a push-back pattern, as shown in Figure 2, an airflow is generated during pressing, eliminating air trapping even if air remains during crushing.

[0018] As shown in Fig. 3, the heat conductive material 2 is applied in a pattern shape of being pushed back in the application process. When the battery module is installed from this state in the installation process, as shown in Fig. 4, the heat conductive material 2 is crushed and spread. Since the battery module is a stacked body in which a plurality of battery cells are stacked, the positions of the battery cells may vary in the height direction. In this case, undulations occur on the lower surface of the power storage module. Also, the bottom 1a of the lower case 1 may have a distorted shape. By making the application locus of the heat conductive material 2 into a pattern shape of being pushed back in the application process, even if air remains during crushing, air entrainment can be eliminated, and a stable thickness and area of the heat conductive material 2 that do not depend on the component shape can be ensured.

[0019] As described above, according to the embodiment, air entrainment during crushing can be suppressed. Thereby, without adding a manufacturing process, the contact failure of the heat conductive material 2 caused by the component shape can be eliminated.

[0020] Also, it is possible to correspond to the component shape regardless of the application position of the heat conductive material 2. Therefore, the contact area with the heat conductive material 2 can be ensured without the need to add a manufacturing process or manufacturing cost.

[0021] Note that in the application process, the angle of the zigzag locus is not limited to 10 to 45 degrees and may be an appropriate angle.

[0022] Also, the manufacturing method of the battery pack may include an application process of applying the heat conductive material 2 to the outer surface of the bottom 1a of the lower case 1, and an attachment process of attaching the cooler to the lower case 1. In this application process, the heat conductive material 2 is applied to the outer surface of the bottom 1a of the lower case 1 so that the application locus of the heat conductive material 2 becomes a pattern shape of being pushed back. The attachment process is a process of attaching the cooler to the bottom 1a of the lower case 1 by pressing the heat conductive material 2 applied in the pattern shape of being pushed back. The attachment process includes a process of crushing the heat conductive material 2 by the cooler so as to sandwich the heat conductive material 2 between the upper surface of the cooler and the outer surface of the bottom 1a.

Explanation of Signs

[0023] 1 Lower Case 1a bottom 2. Thermal conductive material

Claims

1. A method for manufacturing a battery pack comprising a battery module in which multiple battery cells are stacked, A coating step of applying the thermal conductive material to the lower case such that the coating trajectory of the thermal conductive material forms a pushback pattern shape, Installation step of installing the battery module inside the lower case by pressing the heat conductive material applied to the aforementioned push-back pattern shape, A method for manufacturing a battery pack, characterized by including the following:

2. The coating step includes the step of applying the heat conductive material to the inner surface of the bottom of the lower case, The installation step includes a step of crushing the heat conductive material with the battery module so that the heat conductive material is sandwiched between the lower surface of the battery module and the inner surface of the bottom. A method for manufacturing a battery pack according to claim 1.

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