Battery pack manufacturing method

Abstract

To provide a battery pack manufacturing method that can form a thermally conductive layer having consistent thickness.SOLUTION: A method for manufacturing a battery pack according to the present disclosure includes (a) applying a first viscous heat conductive material 2 to a substrate 1, (b) pressing the first viscous heat conductive material applied in the step (a) with a pressing member 3 having projections and recesses to form a pattern in the first viscous heat conductive material, (c) measuring the thickness of the first viscous heat conductive material by image inspection of the pattern of the pressed first viscous heat conductive material to detect a deficient portion 4 where the thickness does not meet a standard value, (d) additionally applying a second viscous heat conductive material 2' to the deficient portion such that the thickness meets the standard value, and (e) after the step (d), pressing and deforming the first and second viscous heat conductive materials with a battery 5 to form a heat conductive layer between the battery and the substrate.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a method for manufacturing a battery pack. [Background technology]

[0002] There is a known technology for constructing a battery pack including a battery module having a plurality of batteries. In such a battery pack, it is considered that the batteries generate heat, and a technology for dissipating the heat inside the battery pack to the outside has been developed. Specifically, there is a known technology for cooling the batteries, which uses a viscous heat conductive material that is placed between the battery module and a cooler and transfers the heat of the batteries to the cooler.

[0003] When assembling a viscous thermally conductive material between a battery module and a cooler, a method may be adopted in which the viscous thermally conductive material is applied to the cooler or its surrounding components, and then a pressure load due to the weight of the battery module is applied to spread the viscous thermally conductive material, thereby interposing the viscous thermally conductive material between the battery module and the cooler, thereby forming a thermally conductive layer.

[0004] For example, Patent Document 1 discloses a battery pack comprising a battery having a heat dissipation surface, a cooler having a cooling surface for cooling the battery, and a viscoelastic layer interposed between the heat dissipation surface of the battery and the cooling surface of the cooler for transferring heat from the battery to the cooler, the battery pack having an expansion restriction portion for restricting a decrease in the thickness of the viscoelastic layer due to the expansion of the viscoelastic layer. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-009672 A Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a method for manufacturing a battery pack capable of forming a thermally conductive layer of a constant thickness. [Means for solving the problem]

[0007] The present inventors have found that the above problems can be solved by the following means. <Aspect 1> A method for manufacturing a battery pack, comprising the steps of: (a) applying a first viscous thermally conductive material to a substrate; (b) pressing the first viscous thermally conductive material applied in step (a) with a pressing member having projections and recesses to form a pattern on the first viscous thermally conductive material; (c) measuring a thickness of the first viscous thermally conductive material by image inspection of the pattern of the pressed first viscous thermally conductive material, and detecting a deficiency portion where the thickness does not meet a reference value; (d) applying an additional amount of the second viscous thermally conductive material to the insufficient portion so as to satisfy the reference value; and (e) after step (d), pressing and deforming the first and second viscous thermally conductive materials with a battery to form a thermally conductive layer between the battery and the substrate; Effect of the Invention

[0008] According to the present disclosure, it is possible to provide a manufacturing method for a battery pack that is capable of forming a thermally conductive layer of a constant thickness. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an example of a manufacturing method for a battery pack according to the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, embodiments of the present disclosure will be described in detail. Note that the present disclosure is not limited to the following embodiments, and various modifications can be made within the scope of the present disclosure.

[0011] <Battery pack manufacturing method> The disclosed method for manufacturing a battery pack includes: (a) applying a first viscous thermally conductive material to a substrate; (b) pressing the first viscous thermally conductive material applied in step (a) with a pressing member having projections and recesses to form a pattern in the first viscous thermally conductive material; (c) measuring a thickness of the first viscous thermally conductive material by image inspection of the pattern of the pressed first viscous thermally conductive material to detect a deficient portion where the thickness does not meet a standard value; (d) additionally applying a second viscous thermally conductive material to the deficient portion so that the thickness meets the standard value; and (e) after step (d), pressing the second viscous thermally conductive material with a battery to deform it, thereby forming a thermally conductive layer between the battery and the substrate.

[0012] The present inventors believed that one of the causes of variation in the thickness of the thermally conductive layer when applying a thermally conductive material to a substrate and spreading the thermally conductive material with a pressing member to form a thermally conductive layer is low rigidity of the substrate. In other words, without intending to be bound by any theory, it is believed that if the substrate has low rigidity, when spreading the thermally conductive material with a pressing member, the substrate will be excessively deformed, making it impossible to form a thermally conductive layer of a uniform thickness.

[0013] In this regard, the present disclosure etc. has found that by pressing a thermally conductive material with a pressing member so as to form a pattern, measuring the thickness of the thermally conductive material by image inspection, applying additional thermally conductive material to areas where the thickness does not meet the standard value, and then pressing again with a battery, a thermally conductive layer of a consistent thickness can be formed even when a coating material with low rigidity is used.

[0014] The method of the present disclosure will be described below with reference to Fig. 1. Fig. 1 is a schematic diagram showing an example of a method of manufacturing a battery pack of the present disclosure. Note that the dimensional relationship in Fig. 1 does not reflect the actual dimensional relationship.

[0015] As shown in FIG. 1( a ), the method of the present disclosure includes (a) applying a first viscous thermally conductive material 2 to a workpiece 1 .

[0016] The coating material 1 may be a cooler constituting a battery pack or a peripheral member thereof. The peripheral member may be a case that covers the cooler. Such a case has a lower rigidity than the pressing member described later, and the effect of the present disclosure is easily achieved.

[0017] The first viscous heat-conducting material 2 may be a composition containing a thermoplastic resin and a heat-conducting component. The types of the thermoplastic resin and the heat-conducting component are not particularly limited.

[0018] As shown in FIG. 1(b), the method of the present disclosure includes (b) pressing the first viscous thermally conductive material 2 applied in step (a) with a pressing member 3 having an uneven surface to form a pattern in the first viscous thermally conductive material 2.

[0019] The pressing member 3 is not particularly limited as long as it can transfer the concaves and convexes to the first viscous thermally conductive material 2 to form a pattern, and a transfer roll is an example of the pressing member 3. When such a pattern is formed, the first viscous thermally conductive material 2 is easily crushed at the convex parts of the pattern when pressed in step (e) described below, and the thermally conductive layer is easily made to have a constant thickness.

[0020] Examples of the pattern include, but are not limited to, stripes, lattices, dots, waves, and the like. When the pattern is stripes, it is easy to inspect the thickness of the first viscous heat conductive material 2 in the image inspection described below. When the pattern is lattice, the viscous heat conductive material is easily crushed when pressed in step (e) described below. When the pattern is dots, the pressing member 3 is less likely to become clogged. When the pattern is wavy, it is easy to control the direction in which the viscous heat conductive material is crushed when pressed in step (e) described below.

[0021] As shown in FIG. 1(b), when pressed by the pressing member 3, the coating target material 1, which has a relatively low rigidity, may be excessively deformed, resulting in the formation of a shortage portion 4, which will be described later.

[0022] As shown in FIG. 1(c), the method of the present disclosure includes (c) measuring the thickness of the first viscous thermally conductive material 2 by image inspection of the pattern of the pressed first viscous thermally conductive material 2 to detect missing portions 4 where the thickness does not meet a standard value.

[0023] The image inspection can be performed using a camera or a laser displacement meter. When a pattern is formed on the first viscous heat conductive material 2, the way in which light is reflected changes compared to when the material is flat, and therefore, during this image inspection, it is easy to measure the thickness of the first viscous heat conductive material 2.

[0024] The reference value for the thickness can be appropriately set depending on the amount of heat generated by the battery, etc.

[0025] In Fig. 1(c), the deficient portion 4 is a portion indicated by a dotted square. Note that, although Fig. 1(c) shows an embodiment in which the deficient portion 4 is formed in a convex portion of the pattern, the deficient portion 4 may be formed in a concave portion of the pattern.

[0026] As shown in FIG. 1(d), the method of the present disclosure includes (d) additionally applying a second viscous thermally conductive material 2' to the insufficient portion 4 so as to satisfy the reference value.

[0027] The second viscous heat conductive material 2' may be the same as or different from the first viscous heat conductive material 2 used in step (a). The amount of the second viscous heat conductive material 2' to be additionally applied is not particularly limited as long as it satisfies a standard value, but can be appropriately set so that the thickness of the heat conductive layer formed after pressing in step (e) described later is uniform.

[0028] As shown in FIG. 1(e), the method of the present disclosure includes, after step (d), (e) pressing and deforming the first and second viscous thermally conductive materials 2, 2' with a battery 5 to form a thermally conductive layer between the battery 5 and the substrate 1.

[0029] The battery 5 can press the viscous thermally conductive material by its own weight. In this case, since there is no need to apply pressure to the battery 5, damage to the battery 5 can be suppressed.

[0030] The battery 5 may be a single battery or a combination of multiple batteries stacked together, ie, a battery module. [Explanation of symbols]

[0031] 1 Material to be coated 2. First Viscous Thermal Conductive Material 2' Second viscous thermal conductive material 3 Pressing member 4 Missing part 5 batteries

Claims

[Claim 1] A method for manufacturing a battery pack, comprising the steps of: (a) applying a first viscous thermally conductive material to a workpiece; (b) pressing the first viscous thermally conductive material applied in step (a) with a pressing member having projections and recesses to form a pattern on the first viscous thermally conductive material; (c) measuring a thickness of the first viscous thermally conductive material by image inspection of the pattern of the pressed first viscous thermally conductive material, and detecting a shortage portion where the thickness does not meet a reference value; (d) applying an additional second viscous thermally conductive material to the insufficient portion so as to satisfy the reference value; and (e) after step (d), pressing and deforming the first and second viscous thermally conductive materials with a battery to form a thermally conductive layer between the battery and the substrate;

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