Battery pack

Abstract

To provide a battery pack which can maintain the cooling function of a battery cell by a cooler.SOLUTION: The battery pack of the present invention includes: a battery module in which a plurality of battery cells with safety valves in the lower surfaces are arranged side by side; and a lower case arranged in the lower part of the battery module. The lower case has a recessed trench part facing the safety valves, and a cooler for cooling the battery cells is arranged in a region of the lower case which is in contact with the battery cells.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a battery pack. [Background technology]

[0002] Patent document 1 discloses a technology in which, in a battery having a battery cell with a pressure release mechanism on the underside and a thermal management member with a groove formed therein, exhaust material ejected from the pressure release mechanism destroys the thermal management member, causing fluid to flow out of the thermal management member and cool the exhaust material. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2022-542786 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology disclosed in Patent Document 1 destroys the thermal management member that functions as a cooler, which may result in the loss of cooling function for battery cells whose pressure release mechanisms are not activated.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a battery pack that can maintain the cooling function of the cooler for the battery cells. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, the battery pack of the present invention is a battery pack comprising a battery module in which a plurality of battery cells, each having a safety valve on its underside, are arranged in a row, and a lower case arranged below the battery module, wherein the lower case has a concave groove portion opposite the safety valve, and a cooler for cooling the battery cells is arranged in the area of ​​the lower case that comes into contact with the battery cells.

[0007] This prevents molten metal and other ejected material from the safety valve of the battery cell from accumulating in the groove of the lower case and affecting the cooler, thereby maintaining the cooler's cooling function for the battery cell.

[0008] In the above, a shear panel that covers the cooler from below is arranged below the lower case, and at least a portion of the groove portion may be made of a material that melts at the temperature of the material ejected from the safety valve.

[0009] This allows the heat generated from the exhaust gas or ejected material that has melted at least a portion of the groove and passed through it to flow around the cooler, thereby enabling cooling control. [Effects of the Invention]

[0010] The battery pack of the present invention has the advantage that ejected material such as molten metal ejected from the safety valve of the battery cell accumulates in the groove of the lower case, thereby preventing the ejected material from affecting the cooler, and thereby maintaining the cooler's cooling function for the battery cell. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic configuration diagram of a main part of a battery pack according to the first embodiment. [Figure 2] FIG. 2 is a cross-sectional view of the battery module in the battery pack according to the first embodiment, cut in a direction perpendicular to the arrangement direction of the battery cells. [Figure 3]FIG. 3 is a cross-sectional view of a battery module in the battery pack according to the first embodiment, cut along the direction in which the battery cells are arranged. [Figure 4] FIG. 4 is a cross-sectional view of a battery module in a battery pack according to the second embodiment, cut in a direction perpendicular to the arrangement direction of the battery cells. [Figure 5] FIG. 5 is a cross-sectional view of a battery module in a battery pack according to the second embodiment, taken along the direction in which the battery cells are arranged. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Embodiment 1) A battery pack according to a first embodiment of the present invention will be described below, although the present invention is not limited to this embodiment.

[0013] Fig. 1 is a schematic configuration diagram of a main part of a battery pack 1 according to embodiment 1. Fig. 2 is a cross-sectional view of a battery module 4 in the battery pack 1 according to embodiment 1, taken in a direction perpendicular to the arrangement direction of the battery cells. Fig. 3 is a cross-sectional view of a battery module 4 in the battery pack 1 according to embodiment 1, taken along the arrangement direction of the battery cells.

[0014] The battery pack 1 according to the embodiment is used as a driving source for vehicles such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), and a plug-in hybrid electric vehicle (PHEV).

[0015] 1, the battery pack 1 according to the first embodiment includes a case 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 when there is no need to particularly distinguish between the plurality of battery modules 4A, 4B, 4C, they are also simply referred to as battery modules 4.

[0016] As shown in Fig. 2, the case 2 is configured as a housing by an upper case 21 and a lower case 22, and accommodates a plurality of battery modules 4A, 4B, and 4C arranged in the battery module arrangement direction Y indicated by the arrow Y in Fig. 1. The upper case 21 and the lower case 22 are made of a metal material such as iron or aluminum. The number of battery modules 4 accommodated in the battery pack 1 is not limited to three, and may be one or more. A share panel 23 is arranged below the lower case 22.

[0017] The battery module 4 is configured by arranging a plurality of battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i side by side in a predetermined direction, that is, a battery cell arrangement direction X indicated by the arrow X in Fig. 1. The battery module 4 also 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 from the battery cell arrangement direction X. The battery module 4 also 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 from the battery module arrangement direction Y.

[0018] In this embodiment, the multiple battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i have the same configuration, and when there is no particular distinction between the multiple battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i, they are simply referred to as battery cells 3. The battery cells 3 are configured using, for example, lithium ion secondary batteries.

[0019] The direction indicated by the arrow Z in FIG. 2 is the battery cell height direction Z (vertical direction) in the battery pack 1 according to the first embodiment. In the battery pack 1 according to the first embodiment, the battery cell height direction Z is the vertical direction. As shown in FIG. 2, 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. 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 configured, for example, by covering a hole opened on the lower surface 30b of the battery cell 3 with a metal film. The safety valve 33 is configured so that when the internal pressure of the battery cell 3 becomes abnormal, the metal film breaks and the hole opens, thereby releasing gas, molten metal, and the like inside the battery cell 3 to the outside of the battery cell 3.

[0020] 3, an elastic body 71 is sandwiched between the end plate 51 and the battery cell 3a in the battery module 4. Similarly, an elastic body 72 is sandwiched between the end plate 52 and the battery cell 3i in the battery module 4. Furthermore, heat insulating materials 8a, 8b, 8c, 8d, 8e, 8f, 8g, and 8h are sandwiched between adjacent battery cells 3 in the battery module 4.

[0021] 2, the battery pack 1 according to the first embodiment has a recessed groove 220 (a downwardly convex shape in the battery cell height direction Z) at a position facing the safety valve 33 of the lower case 22. Also, as shown in FIG. 3, the groove 220 of the lower case 22 is formed below the battery module 4 and extends in the battery cell arrangement direction X.

[0022] In the battery pack 1 according to the first embodiment, coolers 61, 62 are disposed in the area of ​​the lower case 22 that contacts the underside 30b of the battery cell 3 via thermally conductive adhesives 67, 68. The coolers 61, 62 are disposed below the lower case 22, sandwiching a groove 220 in the battery cell width direction (battery module arrangement direction Y). Gaps between the coolers 61, 62 and the lower case 22 are filled with thermally conductive adhesives 64, 65 to improve thermal conductivity and sealing. Gaps between the underside 30b of the battery cell 3 and the lower case 22 are filled with thermally conductive adhesives 67, 68 to improve thermal conductivity and sealing. In the battery pack 1 according to the first embodiment, the shear panel 23 is disposed to cover the cooler 40 from below, protecting the coolers 61, 62. The shear panel 23 is made of a metal material such as iron or aluminum.

[0023] In the battery pack 1 according to the first embodiment, a cooler 63 is disposed in an area of ​​the upper case 21 that comes into contact with the top surfaces 30a of the battery cells 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, thereby improving thermal conductivity and sealing. The gap between the top surfaces 30a of the battery cells 3 and the upper case 21 is filled with a thermally conductive adhesive 69, thereby improving thermal conductivity and sealing.

[0024] In the battery pack 1 according to the first embodiment, a smoke exhaust duct is formed by the lower surface of the battery module 4 (such as the lower surfaces 30b of the plurality of battery cells 3) and the groove 220 of the lower case 22. For example, as shown in FIG. 3 , the smoke exhaust gas G emitted from the safety valve 33e of the battery cell 3e of the battery module 4 passes through the groove 220 of the lower case 22 and is discharged to the outside of the battery pack 1.

[0025] Furthermore, in the battery pack 1 according to the first embodiment, ejected material 10 such as molten metal ejected from the safety valve 33 of the battery cell 3 accumulates in the groove 220 of the lower case 22. Therefore, in the battery pack 1 according to the first embodiment, a greater distance can be secured between the battery cell 3 and the ejected material 10 than in a case where the groove 220 is not provided in the position facing the safety valve 33 of the lower case 22. This prevents the ejected material 10 ejected from the safety valve 33e of the battery cell 3e from coming into contact with the adjacent battery cells 3d and 3f, causing a chain reaction of smoke, as shown in FIG. 3 . Furthermore, the accumulation of the ejected material 10 in the groove 220 of the lower case 22 prevents the ejected material 10 from affecting the coolers 61 and 62, thereby maintaining the cooling function of the coolers 61 and 62 for the battery cell 3.

[0026] (Embodiment 2) A battery pack according to a second embodiment of the present invention will be described below. Note that in this embodiment, the same descriptions as those in the first embodiment will be omitted as appropriate.

[0027] Fig. 4 is a cross-sectional view of the battery module 4 in the battery pack 1 according to embodiment 2, taken in a direction perpendicular to the battery cell arrangement direction. Fig. 5 is a cross-sectional view of the battery module 4 in the battery pack 1 according to embodiment 2, taken along the battery cell arrangement direction.

[0028] In the battery pack 1 according to the second embodiment, as shown in Fig. 4, the bottom portion of the groove 220 of the lower case 22, located directly below the safety valve 33 of the battery cell 3, is formed of a bottom plate 221 made of a resin material that melts at, for example, 200°C. The bottom plate 221 ensures waterproof sealing under normal conditions, not under abnormal conditions where the bottom plate 221 melts due to the heat of flue gas G, as described below. Note that, as shown in Fig. 5, the bottom portions of the groove 220 of the lower case 22, located directly below the safety valves 33a, 33b, 33c, 33d, 33e, 33f, 33g, 33h, and 33i of the multiple battery cells 3a, 3b, 3c, 3d, 3e, 3f, 3g, 3h, and 3i, are formed of bottom plates 221a, 221b, 221c, 221d, 221e, 221f, 221g, 221h, and 221i made of the resin material. In the present embodiment, when the bottom plates 221a, 221b, 221c, 221d, 221e, 221f, 221g, 221h, and 221i are not particularly distinguished from one another, they are also simply referred to as bottom plates 221. In the battery pack 1 according to the second embodiment, the bottom surface portion of the groove 220 is configured by the bottom plate 221, as at least a part of the groove 220, but this is not limited to this. For example, the entire groove 220 (bottom surface portion and side surface portion) may be configured from a material (such as the resin member) that melts at the temperature of the ejection material 10 ejected when the safety valve 33 is opened.

[0029] In the battery pack 1 according to the second embodiment, as shown in Fig. 5, both ends of the groove 220 in the battery cell arrangement direction X are closed by sealing members 91, 92 arranged between the battery module 4 and the lower case 22. In the battery pack 1 according to the second embodiment, as shown in Figs. 4 and 5, a discharge space 230 for discharging exhaust gas G ejected from the safety valve 33 of the battery cell 3 is formed between the lower case 22 and the share panel 23. An oxygen-deficient state is maintained inside the discharge space 230 by increasing the airtightness between the lower case 22 (case 2).

[0030] 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 that connects the groove 220 of the lower case 22 to the exhaust space 230. The exhaust gas G then passes through the communication hole and is discharged from the groove 220 to the exhaust space 230. In addition, 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 sealing members 91, 92, which enables the exhaust gas G that has flowed into the groove 220 to be urged to be discharged into the exhaust space 230.

[0031] As shown in FIG. 5, the flue gas G discharged into the exhaust space 230 flows through the exhaust space 230 in the battery cell arrangement direction X and is discharged to the outside of the battery pack 1 through a smoke exhaust valve (not shown). Furthermore, as shown in FIG. 4, the flue gas G discharged into the exhaust space 230 flows through the exhaust space 230 in the battery cell width direction (battery module arrangement direction Y) toward the area where the coolers 61 and 62 are located, where it is cooled by the coolers 61 and 62. That is, the flue gas G discharged into the exhaust space 230 flows around the vicinity of the coolers 61 and 62, enabling cooling control. This reduces the temperature of the flue gas G and prevents self-ignition. Furthermore, even if a spark is released from the safety valve 33 of a battery cell 3, for example, the spark can be cooled by locating the smoke exhaust valve far from the safety valve 33. This prevents the flue gas G discharged to the outside of the battery pack 1 from igniting due to a spark.

[0032] Furthermore, in the battery pack 1 according to the second embodiment, 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 communication hole and accumulates therein. Therefore, in the battery pack 1 according to the second embodiment, a greater distance can be maintained between the battery cell 3 and the ejected material 10 than in a case where the groove 220 is not provided in the position facing the safety valve 33 of the lower case 22. This prevents the ejected material 10 ejected from the safety valve 33e of the battery cell 3e from coming into contact with the adjacent battery cells 3d and 3f, causing a chain reaction of smoke, as shown in FIG. 5 . Furthermore, as shown in FIG. 4 , accumulation of the ejected material 10 in the discharge space 230 prevents the ejected material 10 from affecting the coolers 61 and 62, thereby maintaining the cooling function of the coolers 61 and 62 for the battery cell 3. Furthermore, the heat emitted from the ejection material 10 discharged into the discharge space 230 flows around the vicinity of the coolers 61 and 62, so that cooling control can be performed. [Explanation of symbols]

[0033] 1 battery pack 2 cases 3 battery cells 4 Battery Module 10 Ejecta 21 Upper Case 22 Lower case 23 Share Panel 30a top surface 30b Bottom side 31 Positive terminal 32 Negative terminal 33 Safety valve 51,52 End plate 53,54 Side plates 61,62,63 Cooler 64,65,66,67,68,69 Thermally conductive adhesive 71,72 Elastic body 91, 92 sealing member 220 Groove 221 Bottom plate 230 Exhaust space G. Flue gas

Claims

1. a battery module in which a plurality of battery cells, each having a safety valve on its underside, are arranged side by side; a lower case disposed below the battery module; A battery pack comprising: the lower case has a recessed groove at a position facing the safety valve, a cooler for cooling the battery cells is disposed in an area of ​​the lower case that contacts the battery cells; A battery pack characterized by:

2. a shear panel that covers the cooler from below is disposed below the lower case, At least a part of the groove is made of a material that melts at the temperature of the ejection material ejected from the safety valve.

2. The battery pack according to claim 1, wherein the battery pack is a battery pack having a plurality of electrodes.

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