Battery module and manufacturing method thereof

Abstract

To suitably seal a battery case with a seal material.SOLUTION: A battery module mounted on a vehicle includes a battery case having an upper case and a lower case, and a seal material. The upper case has a first flange portion provided with a projection on a lower surface thereof. The lower case has a second flange portion opposed to the lower surface of the first flange portion via a gap. The seal member seals the gap between the first flange portion and the second flange portion at a position closer to an inside of the battery case than the projection.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a battery module and a manufacturing method thereof.

[0002] In the battery module disclosed in Patent Document 1, the battery case has an upper case and a lower case. The mating portion between the upper case and the lower case is sealed with a sealing material. This hermetically seals the battery case. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-121916 Summary of the Invention [Problem to be solved by the invention]

[0004] After painting the upper case, When the upper case tilts, Paint applied to the upper case before hardening (For example, paint on the outer surface or outer edge of the upper case) The droplets of From the outer edge of the upper case The paint droplets may flow down the surface of the upper case onto the sealing surface (i.e., the surface that is sealed by the sealant). From the outer edge of the upper case When the paint droplets flow onto the sealing surface, they form a convex shape on the sealing surface. If the sealing surface with the convex shape formed by the paint droplets is then covered with a sealant, the sealing performance at the convex shape location will be reduced. This will result in a decrease in the airtightness of the battery case. This specification proposes a technology for sealing the battery case with a sealant more reliably than conventional technology. [Means for solving the problem]

[0005] The battery module disclosed in this specification is mounted on a vehicle. The battery module includes a battery case having an upper case and a lower case, and a sealing material. The upper case has a first flange portion with a convex portion on its underside. The lower case has a second flange portion facing the underside of the first flange portion with a gap between them. The sealing material seals the gap between the first flange portion and the second flange portion at a position closer to the inside of the battery case than the convex portion.

[0006] In this battery module, a convex portion is provided on the underside of the first flange portion of the upper case. The sealing material is positioned closer to the inside of the battery case than the convex portion. Therefore, the sealing surface of the upper case is a portion of the underside of the first flange portion that is closer to the inside of the battery case than the convex portion. After painting the upper case, droplets of paint before hardening may flow from the outer periphery of the first flange portion along the underside of the first flange portion toward the sealing surface. In this case, the convex portion prevents the paint droplets from flowing toward the sealing surface. Therefore, a convex shape is less likely to form on the sealing surface of the upper case. Therefore, when sealing the gap between the first flange portion and the second flange portion with the sealing material, the sealing material can adhere to the sealing surface of the upper case. Therefore, a high level of airtightness can be achieved in the battery case.

[0007] This specification proposes a method for manufacturing a battery module to be mounted on a vehicle, which includes the steps of: painting at least an outer surface of an upper case having a first flange portion with a convex portion on its underside; arranging the upper case on top of a lower case having a second flange portion such that the second flange portion faces the underside of the first flange portion with a gap therebetween; and sealing the gap between the first flange portion and the second flange portion with a sealant at a position closer to the inside of the battery case formed by the upper case and the lower case than the convex portion.

[0008] This manufacturing method prevents droplets of uncured paint from flowing to the sealing surface after painting the upper case by the protrusions. This allows the sealing material to adhere tightly to the sealing surface of the upper case when applied. This allows for the production of a battery module with high airtightness. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a battery module 10. [Figure 2] FIG. 2 is an exploded perspective view of the battery module 10. [Figure 3] FIG. 2 is a vertical cross-sectional view of the outer periphery of the battery module 10. [Figure 4] FIG. 3 is a plan view of the flange portion 14c of the upper case 14 as seen from above. [Figure 5] FIG. 10 is a cross-sectional view showing the upper case 14 during movement. DETAILED DESCRIPTION OF THE INVENTION

[0010] The battery module 10 of the embodiment shown in Fig. 1 has a battery case 12. The battery case 12 has an upper case 14 and a lower case 16. As shown in Fig. 2, a plurality of battery stacks 20 are housed inside the battery case 12. Each battery stack 20 is a member in which a plurality of battery cells are stacked.

[0011] The lower case 16 is made of metal. The surface of the lower case 16 is painted. The lower case 16 has a bottom plate 16a and an outer peripheral wall 16b that extends upward from the outer peripheral edge of the bottom plate 16a. Multiple battery stacks 20 are arranged on the bottom plate 16a. The lower case 16 also has a flange portion 16c that extends from the upper edge of the outer peripheral wall 16b toward the outside of the battery case 12.

[0012] The upper case 14 is made of metal. The surface of the upper case 14 is painted. The upper case 14 has a top plate 14a and an outer peripheral wall 14b extending downward from the outer peripheral edge of the top plate 14a. The upper case 14 also has a flange portion 14c extending from the lower edge of the outer peripheral wall 14b toward the outside of the battery case 12. As shown in FIG. 3, the upper case 14 is disposed above the lower case 16 so that the lower surface of the flange portion 14c faces the upper surface of the flange portion 16c. A gap 30 is provided between the lower surface of the flange portion 14c and the upper surface of the flange portion 16c. The upper case 14 and the lower case 16 are fixed to each other by a connecting member (not shown).

[0013] As shown in Figures 3 and 4, a protrusion 18 is provided on the flange portion 14c of the upper case 14. As shown in Figure 3, the protrusion 18 protrudes downward from the lower surface of the flange portion 14c. The protrusion 18 is formed by a bent portion of a metal plate that constitutes the upper case 14. As shown in Figure 4, the protrusion 18 extends linearly along the flange portion 14c (i.e., along the outer peripheral edge of the upper case 14).

[0014] As shown in FIG. 3, a sealant 40 is disposed in the gap 30 between the flange portion 14c and the flange portion 16c. The sealant 40 is made of, for example, urethane resin. The sealant 40 is disposed in a position closer to the inside of the battery case 12 than the protrusion 18. The sealant 40 is bonded to the lower surface of the flange portion 14c and the upper surface of the flange portion 16c. The sealant 40 seals the gap 30. More specifically, the sealant 40 extends along the flange portions 14c, 16c (i.e., along the outer peripheral edge of the battery case 12) and seals the gap 30.

[0015] In the following description, the surface of the lower surface of the flange portion 14c that is sealed by the sealing material 40 is referred to as a sealing surface 14s.

[0016] Next, a method for manufacturing the battery module 10 will be described. First, the entire surface of the upper case 14 is painted. For example, the upper case 14 can be painted by cationic coating. In the case of cationic coating, the entire upper case 14 is immersed in paint, and a voltage is applied between the upper case 14 and an electrode immersed in the paint. Therefore, when the upper case 14 is removed from the paint after painting, uncured paint remains on the surface of the upper case 14.

[0017] FIG. 5 shows the state of the painted upper case 14 during movement. As shown in FIG. 5, the upper case 14 may tilt during movement. Furthermore, as described above, uncured paint remains on the surface of the painted upper case 14. If the upper case 14 tilts as shown in FIG. 5 before the paint on the surface of the upper case 14 dries, the uncured paint on the outer surface of the upper case 14 and the outer periphery of the flange portion 14c may form droplets 50 and flow along the underside of the flange portion 14c. When the droplets 50 flow along the underside of the flange portion 14c to the sealing surface 14s, the paint constituting the droplets 50 hardens on the sealing surface 14s, forming a convex shape on the sealing surface 14s. In contrast, in the manufacturing method of this embodiment, the convex portions 18 formed on the underside of the flange portion 14c prevent the droplets 50 from reaching the sealing surface 14s. That is, because the convex portion 18 exists between the outer peripheral edge of the flange portion 14c and the sealing surface 14s, the droplets 50 flowing from the outer peripheral edge of the flange portion 14c must pass through the convex portion 18 to reach the sealing surface 14s. However, the outer side surface 18a of the convex portion 18 prevents the droplets 50 from moving closer to the sealing surface 14s than the side surface 18a. Even if the droplets 50 flow beyond the side surface 18a to the lower surface 18b of the convex portion 18, the inner side surface 18c of the convex portion 18 extends upward from the lower surface 18b, making it difficult for the droplets 50 to flow from the lower surface 18b to the side surface 18c. Therefore, the droplets 50 are prevented from reaching the sealing surface 14s. In this way, the convex portion 18 prevents the paint droplets 50 from flowing to the sealing surface 14s. This prevents the formation of a convex shape on the sealing surface 14s.

[0018] Although cationic coating has been described as an example of the coating process above, the upper case 14 may be coated by a coating method other than cationic coating. Even in this case, the protrusions 18 prevent uncured paint from flowing onto the sealing surface 14s.

[0019] The lower case 16 is painted in the same manner as the upper case 14. Once the paint on the upper case 14 and the lower case 16 has dried, the battery stack 20 is placed on the lower case 16, as shown in Fig. 2. Next, the upper case 14 is placed on the battery stack 20. That is, as shown in Fig. 3, the upper case 14 is placed on the lower case 16 so that the lower surface of the flange portion 14c faces the lower surface of the flange portion 16c with a gap 30 between them.

[0020] Next, as shown in FIG. 3, the gap 30 is filled with a sealing material 40 made of a urethane resin adhesive. Here, the sealing material 40 is filled into the gap 30 at a position closer to the inside of the battery case 12 than the protrusion 18. The filled sealing material 40 adheres to the sealing surface 14s on the lower surface of the flange portion 14c and the upper surface of the flange portion 16c. When the sealing material 40 is then cured, the sealing material 40 is adhered to the sealing surface 14s and the upper surface of the flange portion 16c. The gap 30 is sealed by the sealing material 40.

[0021] As described above, the protrusions 18 prevent the uncured paint droplets 50 from flowing to the sealing surface 14s, thereby preventing the formation of a convex shape on the sealing surface 14s. Therefore, when the sealing material 40 is filled into the gap 30, the sealing material 40 can adhere closely to the sealing surface 14s. Therefore, when the sealing material 40 is subsequently cured, the sealing material 40 seals the gap 30 with high airtightness.

[0022] Furthermore, the strength of the flange portion 14c is improved by providing the protrusions 18 on the flange portion 14c of the upper case 14. This improves the strength of the outer periphery of the battery case 10, and suppresses deformation of the outer periphery of the battery case 10.

[0023] In the above-described embodiment, the entire surface of the upper case 14 is painted, but it is not necessary to paint the inner surface of the upper case 14 and the underside of the flange portion 14c. As long as at least the outer surface of the upper case 14 is painted, the protrusions 18 can prevent uncured paint from flowing onto the sealing surface 14s.

[0024] Although the embodiments have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings simultaneously achieves multiple objectives, and achieving one of these objectives itself has technical utility. [Explanation of symbols]

[0025] 10: Battery module 12: Battery case 14: Upper case 14c: Flange part 14s: Sealing surface 16: Lower case 16c: Flange part 18: Convex part 20: Battery stack 30: Gap 40: Sealing material

Claims

1. A battery module mounted on a vehicle, a battery case having an upper case and a lower case; A sealing material; and the upper case has a first flange portion having a convex portion on its lower surface, the lower case has a second flange portion that faces the lower surface of the first flange portion with a gap therebetween, the sealing material seals the gap between the first flange portion and the second flange portion at a position closer to the inside of the battery case than the protrusion. Battery module.

2. A method for manufacturing a battery module to be mounted on a vehicle, a step of painting at least an outer surface of an upper case having a first flange portion with a convex portion provided on a lower surface thereof; a step of disposing the upper case on an upper part of a lower case having a second flange portion such that the second flange portion faces the lower surface of the first flange portion with a gap therebetween; sealing the gap between the first flange portion and the second flange portion with a sealant at a position closer to an inside of a battery case formed by the upper case and the lower case than the protrusion; A manufacturing method comprising the steps of:

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