Battery pack

Abstract

To obtain a battery pack that can improve thermal insulation performance without hindering miniaturization of the battery pack. [Solution] The battery pack comprises a case that surrounds the cells, and an insulating material located between the case and the cells, which at least covers the ejection region from which ejected material is ejected from the cells, wherein the heat resistance of the first adhesive that adheres the first region of the insulating material located in the ejection region to the case is lower than the heat resistance of the second adhesive that adheres the second region of the insulating material, excluding the first region, to the case.

Description

Technical Field

[0001] The present disclosure relates to a battery pack.

Background Art

[0002] Patent Document 1 discloses a description of alleviating heat propagation between battery cells in a battery pack.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] Here, for example, in a lithium battery cell (hereinafter referred to as "cell"), high - temperature ejecta can be released from the cell due to abnormal internal heat generation. When the coating on the surface of the battery case (hereinafter referred to as "case") that covers the outside of the cell adheres to the case, there is a risk of ignition due to the heat of the ejecta transmitted through the case. As a solution, for example, to provide a heat - insulating material with a sufficient thickness to suppress ignition between the cell and the case, the space inside the case becomes large, which may prevent miniaturization of the battery pack.

[0005] In consideration of the above facts, an object of the present disclosure is to obtain a battery pack capable of improving heat insulation performance without preventing miniaturization of the battery pack.

Means for Solving the Problems

[0006] The battery pack according to claim 1 of the present disclosure comprises a case that surrounds a cell, and an insulating material located between the case and the cell, which at least covers an ejection region from which ejected material is ejected from the cell, wherein the heat resistance of a first adhesive that adheres a first region of the insulating material located in the ejection region to the case is lower than the heat resistance of a second adhesive that adheres a second region of the insulating material, excluding the first region, to the case.

[0007] With the battery pack according to claim 1 of the present disclosure, the heat of the ejected material causes the first adhesive itself to peel off from the case, or the first region 4a of the heat insulating material to peel off from the first adhesive, making it difficult for the heat of the ejected material to be transferred to the paint on the case, thereby suppressing ignition due to heat.

[0008] In the battery pack according to claim 2 of the present disclosure, the first region after the ejected material has been ejected is separated from the case.

[0009] With the battery pack according to claim 2 of the present disclosure, the air layer functions as an insulating layer, making it more difficult for the heat of the ejected material to be transferred to the paint of the case, and thus further suppressing ignition due to heat.

[0010] The battery pack according to claim 3 of the present disclosure is provided such that the first region is located in a position corresponding to the nozzle from which the ejected material is ejected, when the case is viewed from above.

[0011] The battery pack according to the present disclosure as described in claim 3 makes it easier for the heat insulating material in the first region, where ejected material from the cells tends to adhere, to peel off from the case, and makes it more difficult for heat to be transferred to the case, thereby suppressing ignition due to heat. [Effects of the Invention]

[0012] As explained above, the battery pack relating to this disclosure can improve thermal insulation performance without hindering miniaturization of the battery pack. [Brief explanation of the drawing]

[0013] [Figure 1]Figure 1 is a cross-sectional view of a battery pack 1 according to an embodiment of the present disclosure. [Figure 2] Figure 2 is an enlarged view of the portion indicated by the symbol A in Figure 1. [Figure 3] Figure 3 is a diagram illustrating how a portion of the insulation material 4 peels off from case 3 when ejected material 100 adheres to it. [Figure 4] Figure 4 is a diagram illustrating how a portion of the insulation material 4 peels off from the case 3 when ejected material 100 adheres to it. [Figure 5] Figure 5 is a diagram illustrating how a portion of the insulation material 4 peels off from case 3 when ejected material 100 adheres to it. [Modes for carrying out the invention]

[0014] The battery pack will now be described with reference to the drawings. Figures 1 and 2 are cross-sectional views of a battery pack 1 according to an embodiment of this disclosure. Figure 2 shows an enlarged view of the portion indicated by reference numeral A in Figure 1.

[0015] The battery pack 1 may include a plurality of cells 2, a case 3 that surrounds the plurality of cells 2 and whose surface is painted 3a, and an insulating material 4.

[0016] The coating 3a around case 3 is, for example, cationic electrodeposition coating.

[0017] The thermal insulation material 4 is located between the case 3 and the cell 2 and may at least cover the ejection region 5 from which the ejected material 100 is ejected from the cell 2. For example, the thermal insulation material 4 may include a first region 4a of the thermal insulation material 4 located above the ejection region 5 and a second region 4b of the thermal insulation material 4 excluding the first region 4a. The first region 4a of the thermal insulation material 4 may be provided in a position corresponding to the nozzle 101 from which the ejected material 100 is ejected when the case 3 is viewed from above.

[0018] The heat resistance of the first adhesive 6a that adheres the first region 4a of the heat insulating material 4 to the case 3 is lower than the heat resistance of the second adhesive 6b that adheres the second region 4a of the heat insulating material 4 to the case 3. For example, the first adhesive 6a and the second adhesive 6b may be composed of a liquid material or a tape-like material. Specifically, the heat resistance of the first adhesive 6a may be composed of a material having a heat resistance that deforms at the temperature of the ejecta 100, and the heat resistance of the second adhesive 6b may be composed of a material having a heat resistance that does not deform at the temperature of the ejecta 100, that is, a heat resistance higher than the temperature of the ejecta 100. Note that the materials constituting the first adhesive 6a and the second adhesive 6b are, for example, acrylic resin, epoxy resin, urethane resin, and the like.

[0019] The width of the first region 4a of the heat insulating material 4 may be any value from 0.5 times to 4.0 times the opening width of the ejection port 101, for example. By increasing the width of the first region 4a of the heat insulating material 4, as will be described later, the region where the heat insulating material 4 peels off from the case 3 becomes wider, and the volume of the air layer between the heat insulating material 4 and the case 3, which functions as a heat insulating layer, can be increased.

[0020] Next, referring to FIGS. 3 to 5, the state in which a part of the heat insulating material 4 peels off from the case 3 when the ejecta 100 adheres will be described.

[0021] As shown in FIG. 3, when the ejecta 100 ejected from the ejection port 101 adheres to a part of the heat insulating material 4 located in the ejection region 5, that is, the first region 4a, the heat of the ejecta 100 is transmitted to the first adhesive 6a through the heat insulating material 4. As described above, since the first adhesive 6a includes a material having a heat resistance that deforms at the temperature of the ejecta 100, as shown in FIG. 4, due to the heat of the ejecta 100, the first adhesive 6a itself peels off from the case 3, or the first region 4a of the heat insulating material 4 peels off from the first adhesive 6a.

[0022] On the other hand, since the heat resistance of the second adhesive 6b includes a material having a heat resistance that does not deform at the temperature of the ejecta 100, that is, a heat resistance higher than the temperature of the ejecta 100, the second adhesive 6b does not peel off from the case 3, or the second region 4b of the heat insulating material 4 does not peel off from the second adhesive 6b.

[0023] As a result, as shown in Figure 5, an air layer 7 is formed between a portion of the insulation material 4 and the case 3. In other words, thermal insulation is formed between the first region 4a of the insulation material 4, to which the ejected material 100 easily adheres, and the case 3, or between the first adhesive 6a and the case 3. After the ejected material 100 is ejected, the first region 4a is separated from the case 3.

[0024] Thus, in the battery pack according to the embodiment of this disclosure, the heat resistance of the first adhesive 6a that adheres the first region 4a of the heat insulating material 4 to the case 3 is lower than the heat resistance of the second adhesive 6b that adheres the second region 4b of the heat insulating material 4 (excluding the first region 4a) to the case 3, and an air layer 7 is formed between the first region 4a and the case 3 after the ejected material 100 is ejected.

[0025] With this configuration, the heat from the ejected material 100 causes the first adhesive 6a itself to peel off from the case 3, or the first region 4a of the insulating material 4 to peel off from the first adhesive 6a. As a result, the heat from the ejected material 100 is less likely to be transferred to the paint on the case 3, and ignition due to heat can be suppressed.

[0026] Furthermore, because the air layer 7 functions as an insulating layer, the heat from the ejected material 100 is less likely to be transferred to the paint of case 3, further suppressing ignition due to heat.

[0027] Furthermore, the air layer 7 improves insulation performance, allowing for improved insulation performance by utilizing the limited space inside Case 3.

[0028] Furthermore, because the thermal insulation performance is improved, there is no need to add space for the thicker thermal insulation material 4, so the thermal insulation performance can be improved while maintaining the shape and size of the existing case 3 and the shape and size of the cell 2. In addition, the thermal insulation performance can be improved without hindering the miniaturization of the battery pack 1.

[0029] Furthermore, thin heat-resistant insulation material 4 is expensive and scarce, so using such insulation material 4 could increase the manufacturing cost of the battery pack 1 and potentially lead to a supply shortage. In contrast, the battery pack according to the embodiment of this disclosure can utilize general-purpose insulation material 4, thereby suppressing the increase in the manufacturing cost of the battery pack 1 while suppressing ignition due to heat. [Explanation of symbols]

[0030] 1 Battery pack 2 cells 3 cases 3a Painting 4. Insulation 4a 1st area 4b 2nd area 5 Ejection area 6a First adhesive 6b Second adhesive 7. Air layer 100 Ejecta 101 spout

Claims

1. A case that surrounds the cell, A thermal insulation material located between the case and the cell, which at least covers the ejection region from which ejected material is ejected from the cell, Equipped with, A battery pack in which the heat resistance of the first adhesive used to bond the first region of the insulating material located in the ejection region to the case is lower than the heat resistance of the second adhesive used to bond the second region of the insulating material, excluding the first region, to the case.

2. The battery pack according to claim 1, wherein the first region after the ejected material has been ejected is detached from the case.

3. The battery pack according to claim 1, wherein the first region is provided in a position corresponding to the nozzle from which the ejected material is ejected when the case is viewed from above.

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