Battery pack

Abstract

The utility model provides a battery pack capable of maintaining a cooling function of a cooler on a battery unit. The battery pack includes: a battery module having a plurality of battery cells arranged in an array, the lower surface of the battery module being provided with a safety valve; and a lower case disposed below the battery module, the lower case having a recessed groove portion at a position facing the safety valve, and a cooler disposed in a region in contact with the battery cell in the lower case for cooling the battery cell.

Description

Technical Field

[0001] The utility model relates to a battery pack. Background Art

[0002] Patent document 1 discloses a battery technology comprising a battery cell and a thermal management component. A pressure relief mechanism is provided on the lower surface of the battery cell, and a groove is formed in the thermal management component. The thermal management component is damaged by the discharge ejected from the pressure relief mechanism, causing the fluid to flow out of the thermal management component and cool the discharge.

[0003] Patent Document 1: Japanese Patent Application No. 2022-542786

[0004] However, in the technology disclosed in Patent Document 1, since the heat management component must be destroyed in order to function as a cooler, there is a risk that the cooling function for the battery cells whose pressure relief mechanisms are not activated will be lost. Utility Model Content

[0005] The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a battery pack capable of maintaining the cooling function of a cooler on battery cells.

[0006] In order to solve the above-mentioned problems and achieve the above-mentioned objectives, the battery pack involved in the present invention includes: a battery module having a plurality of arranged battery cells, a safety valve being provided on the lower surface of the battery module; and a lower shell being arranged below the battery module, the lower shell having a concave groove at a position opposite to the safety valve, and a cooler for cooling the battery cells being arranged in the area of the lower shell that contacts the battery cells.

[0007] Thus, the ejected material, such as molten metal, ejected from the safety valve of the battery cell is accumulated in the groove portion of the lower case, thereby suppressing the influence of the ejected material on the cooler and maintaining the cooler's function of cooling the battery cell.

[0008] In the battery pack, a common panel covering the cooler from below may be disposed below the lower case, and at least a portion of the groove may be made of a material that melts at a temperature of a substance ejected from the safety valve.

[0009] As a result, at least a portion of the groove portion is melted, and heat generated from the passing exhaust gas or ejected matter is directed around the vicinity of the cooler, thereby enabling cooling control.

[0010] The battery pack of the present invention has the effect that the ejected material such as molten metal ejected from the safety valve of the battery cell is accumulated in the groove portion of the lower case, thereby suppressing the influence of the ejected material on the cooler and maintaining the cooling function of the cooler on the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram showing the configuration of the main parts of the battery pack according to the first embodiment.

[0012] Figure 2 This is a cross-sectional view of the battery module cut along a direction perpendicular to the battery cell arrangement direction in the battery pack according to the first embodiment.

[0013] Figure 3 This is a cross-sectional view of the battery module cut along the battery cell arrangement direction in the battery pack according to the first embodiment.

[0014] Figure 4 This is a cross-sectional view of the battery module cut along a direction perpendicular to the battery cell arrangement direction in the battery pack according to the second embodiment.

[0015] Figure 5 This is a cross-sectional view of a battery module cut along the battery cell arrangement direction in the battery pack according to the second embodiment. DETAILED DESCRIPTION

[0016] Hereinafter, a first embodiment of the battery pack according to the present invention will be described. However, the present invention is not limited to this embodiment.

[0017] Figure 1 This is a schematic diagram showing the configuration of the main parts of the battery pack 1 according to the first embodiment. Figure 2 This is a cross-sectional view of the battery module 4 cut along a direction perpendicular to the battery cell arrangement direction in the battery pack 1 according to the first embodiment. Figure 3 This is a cross-sectional view of the battery module 4 cut along the battery cell arrangement direction in the battery pack 1 according to the first embodiment.

[0018] The battery pack 1 according to the embodiment can be used as a driving source for a vehicle, for example, in a BEV (Battery Electric Vehicle), an HEV (Hybrid Electric Vehicle), or a PHEV (Plug-in Hybrid Electric Vehicle).

[0019] like Figure 1 As shown, the battery pack 1 according to the first embodiment includes a housing 2 and a plurality of battery modules 4A, 4B, 4C, etc. In the battery pack 1 according to the first embodiment, the plurality of battery modules 4A, 4B, 4C have the same configuration and are collectively referred to as battery modules 4 unless otherwise specified.

[0020] like Figure 2As shown, the housing 2 is composed of an upper housing 21 and a lower housing 22. Figure 1 Multiple battery modules 4A, 4B, and 4C are arranged and housed in the battery module arrangement direction Y indicated by the arrow Y in FIG. The upper housing 21 and lower housing 22 are made of a metal material such as iron or aluminum. The number of battery modules 4 housed in the battery pack 1 is not limited to three; it can be one or more. A common panel 23 is disposed below the lower housing 22.

[0021] The battery module 4 is in a prescribed direction. Figure 1 The battery module 4 is constructed by arranging a plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i in the battery cell arrangement direction X indicated by the arrow X in FIG. Furthermore, the battery module 4 includes a pair of end plates 51 and 52 that sandwich the plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i in the battery cell arrangement direction X. Furthermore, the battery module 4 includes a pair of side plates 53 and 54 that sandwich the plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i in the battery module arrangement direction Y.

[0022] In the present embodiment, the plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i have the same configuration and, unless otherwise specified, are collectively referred to as battery cells 3. The battery cells 3 are configured using, for example, lithium-ion secondary batteries.

[0023] Figure 2 The direction indicated by the arrow Z in the figure is the battery cell height direction Z (vertical direction) in the battery pack 1 according to the first embodiment. In addition, in the battery pack 1 according to the first embodiment, the battery cell height direction Z is the vertical direction. Figure 2 As shown, a pair of electrode terminals, a positive terminal 31 and a negative terminal 32, are provided on the upper surface 30a of the battery cell 3. In addition, a safety valve 33 is provided on the lower surface 30b of the battery cell 3. The safety valve 33 is located approximately in the center between the positive terminal 31 and the negative terminal 32 in the width direction of the battery cell 3 (the battery module arrangement direction Y). The safety valve 33 is formed, for example, by adhering a metal film to a hole opened in the lower surface 30b of the battery cell 3 and blocking it. The safety valve 33 is configured so that when the internal pressure of the battery cell 3 becomes abnormal, the metal film ruptures to open the hole, thereby releasing gas or molten metal inside the battery cell 3 to the outside of the battery cell 3.

[0024] like Figure 3As shown, in the battery module 4, an elastic body 71 is sandwiched between the end plate 51 and the battery cell 3a. Similarly, in the battery module 4, an elastic body 72 is sandwiched between the end plate 52 and the battery cell 3i. In addition, in the battery module 4, heat insulating materials 8a, 8b, 8c, 8d, 8e, 8f, 8g, and 8h are sandwiched between adjacent battery cells 3, respectively.

[0025] like Figure 2 As shown, in the battery pack 1 according to the first embodiment, the lower case 22 has a concave (convex downward in the battery cell height direction Z) groove 220 at a position opposite to the safety valve 33. Figure 3 As shown, it is formed below the battery module 4 along the battery cell arrangement direction X.

[0026] In the battery pack 1 according to the first embodiment, coolers 61 and 62 are arranged in the region of the lower case 22 that contacts the lower surface 30b of the battery cell 3 via thermally conductive adhesives 67 and 68. Coolers 61 and 62 are arranged below the lower case 22, sandwiching the groove 220 in the battery cell width direction (battery module arrangement direction Y). The gaps between the coolers 61 and 62 and the lower case 22 are filled with thermally conductive adhesives 64 and 65, thereby improving thermal conductivity and airtightness. Furthermore, the gaps between the lower surface 30b of the battery cell 3 and the lower case 22 are filled with thermally conductive adhesives 67 and 68, thereby improving thermal conductivity and airtightness. Furthermore, in the battery pack 1 according to the first embodiment, a common panel 23 is arranged to cover the cooler 40 from below, thereby protecting the coolers 61 and 62. The common panel 23 is made of a metal material such as iron or aluminum, for example.

[0027] Furthermore, in the battery pack 1 according to the first embodiment, a cooler 63 is disposed in the region of the upper case 21 that contacts the upper surface 30a of the battery cell 3 via a thermally conductive adhesive 69. The cooler 63 is located above the upper case 21, approximately in the center between the positive electrode terminal 31 and the negative electrode terminal 32 in the battery cell width direction (battery module arrangement direction Y). The gap between the cooler 63 and the upper case 21 is filled with a thermally conductive adhesive 66 to improve thermal conductivity and airtightness. Furthermore, the gap between the upper surface 30a of the battery cell 3 and the upper case 21 is filled with a thermally conductive adhesive 69 to improve thermal conductivity and airtightness.

[0028] In the battery pack 1 according to the first embodiment, the smoke exhaust duct is formed by the lower surface of the battery module 4 (the lower surface 30b of the plurality of battery cells 3, etc.) and the groove 220 of the lower case 22. Figure 3As shown, exhaust gas G ejected from the safety valve 33 e of the battery cell 3 e of the battery module 4 is discharged to the outside of the battery pack 1 through the groove portion 220 of the lower case 22 .

[0029] Furthermore, in the battery pack 1 according to the first embodiment, the ejected material 10, such as molten metal, ejected from the safety valve 33 of the battery cell 3 is accumulated in the groove 220 of the lower case 22. Therefore, in the battery pack 1 according to the first embodiment, the distance between the battery cell 3 and the ejected material 10 can be ensured compared to a case where the groove 220 is not provided at a position opposite to the safety valve 33 of the lower case 22. Thus, for example Figure 3 As shown, the spray 10 ejected from the safety valve 33e of the battery cell 3e can be prevented from contacting the adjacent battery cells 3d and 3f and causing a chain reaction of smoke. Furthermore, since the spray 10 is accumulated in the groove 220 of the lower case 22, the spray 10 is prevented from affecting the coolers 61 and 62, thereby maintaining the cooling function of the coolers 61 and 62 for the battery cells 3.

[0030] Hereinafter, a second embodiment of the battery pack according to the present invention will be described. In this embodiment, the same description as in the first embodiment will be omitted as appropriate.

[0031] Figure 4 This is a cross-sectional view of the battery module 4 cut along a direction perpendicular to the battery cell arrangement direction in the battery pack 1 according to the second embodiment. Figure 5 This is a cross-sectional view of the battery module 4 cut along the battery cell arrangement direction in the battery pack 1 according to the second embodiment.

[0032] like Figure 4 As shown, in the battery pack 1 according to the second embodiment, the bottom surface portion of the groove 220 of the lower case 22, located immediately below the safety valve 33 of the battery cell 3, is formed of a bottom plate 221 made of, for example, a resin member that melts at 200°C. The bottom plate 221 ensures waterproof sealing under normal circumstances, but does not in the event of an abnormality such as melting due to the heat of the exhaust gas G as will be described later. Figure 5As shown, the bottom surface portion of the groove portion 220 of the lower case 22, located directly below the safety valves 33a, 33b, 33c, 33d, 33e, 33f, 33g, 33h, and 33i of the plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 33g, 33h, and 33i, is formed by the bottom plates 221a, 221b, 221c, 221d, 221e, 221f, 221g, 221h, and 221i made of the above-mentioned resin member. In this embodiment, the bottom plates 221a, 221b, 221c, 221d, 221e, 221f, 221g, 221h, and 221i are collectively referred to as the bottom plate 221 unless otherwise specified. In the battery pack 1 according to the second embodiment, the bottom portion of the groove 220 is formed of the bottom plate 221 as at least a portion of the groove 220. However, this is not limiting. For example, the entire groove 220 (bottom and side portions) may be formed of a material (such as the aforementioned resin member) that melts at the temperature of the ejected material 10 ejected when the safety valve 33 opens.

[0033] like Figure 5 As shown, in the battery pack 1 according to the second embodiment, both ends of the groove 220 in the battery cell arrangement direction X are closed by the sealing members 91 and 92 disposed between the battery module 4 and the lower case 22. Figure 4 and Figure 5 As shown, in the battery pack 1 according to the second embodiment, a discharge space 230 is formed between the lower case 22 and the common panel 23 for discharging exhaust gas G emitted from the safety valve 33 of the battery cell 3. The airtightness between the discharge space 230 and the lower case 22 (case 2) is improved, thereby maintaining an oxygen-deficient state.

[0034] In the battery pack 1 according to the second embodiment, the bottom plate 221 of the groove 220 is melted by the high-temperature exhaust gas G ejected from the safety valve 33 of the battery cell 3, thereby forming a communication hole connecting the groove 220 of the lower case 22 with the exhaust space 230. The exhaust gas G then flows from the groove 220 into the exhaust space 230 through the communication hole. Furthermore, in the battery pack 1 according to the second embodiment, since both ends of the groove 220 in the battery cell arrangement direction X are sealed by the sealing members 91 and 92, the exhaust gas G flowing into the groove 220 can be encouraged to be discharged into the exhaust space 230.

[0035] like Figure 5 As shown, the exhaust gas G discharged into the exhaust space 230 flows in the battery cell arrangement direction X within the exhaust space 230 and is discharged to the outside of the battery pack 1 through the exhaust valve (not shown). Figure 4As shown, the exhaust gas G flows in the battery cell width direction (battery module arrangement direction Y) within the exhaust space 230 toward the area having the coolers 61 and 62, thereby being cooled by the coolers 61 and 62. That is, the exhaust gas G discharged into the exhaust space 230 flows around the coolers 61 and 62, so that cooling control can be performed. As a result, the temperature of the exhaust gas G can be lowered and spontaneous combustion can be suppressed. In addition, for example, even if a spark is emitted from the safety valve 33 of the battery cell 3, the spark can be cooled by arranging the exhaust valve at a position away from the safety valve 33. As a result, the exhaust gas G discharged from the exhaust valve to the outside of the battery pack 1 can be suppressed from being ignited by the spark.

[0036] Furthermore, in the battery pack 1 according to the second embodiment, the ejected material 10, such as molten metal, ejected from the safety valve 33 of the battery cell 3 is discharged into the discharge space 230 through the above-mentioned communication hole and is accumulated in the discharge space 230. Therefore, in the battery pack 1 according to the second embodiment, the distance between the battery cell 3 and the ejected material 10 can be ensured compared to a case where the groove 220 is not provided at a position opposite to the safety valve 33 of the lower case 22. Thus, for example Figure 5 As shown in FIG. 1 , it is possible to suppress the chain reaction in which the ejection 10 ejected from the safety valve 33e of the battery cell 3e contacts the battery cells 3d and 3f adjacent to the battery cell 3e and causes smoke. Figure 4 and Figure 5 As shown, since the ejected matter 10 accumulates in the discharge space 230, the ejected matter 10 is prevented from affecting the coolers 61 and 62, thereby maintaining the cooling function of the coolers 61 and 62 on the battery cells 3. In addition, since the heat generated by the ejected matter 10 discharged into the discharge space 230 is circulated around the coolers 61 and 62, cooling control can be achieved.

Claims

1. A battery pack, characterized in that: include: A battery module having a plurality of arranged battery cells, wherein a safety valve is provided on the lower surface of the battery module; and The lower housing is arranged below the battery module. The lower housing has a concave groove at a position opposite to the safety valve. A cooler for cooling the battery cells is disposed in a region of the lower case that contacts the battery cells.

2. The battery pack according to claim 1, wherein: A common panel is disposed below the lower case and covers the cooler from below. At least a portion of the groove is made of a material that melts at a temperature of a spray ejected from the safety valve.

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