Battery Structure

Abstract

To obtain a battery structure that can cool the gas emitted from the battery cell. [Solution] In the battery pack 10, a thermal conductive sheet 38 is interposed between the lower surface of the bottom wall portion 18A of the battery case 12 and the cooling circuit portion 34. A portion of this thermal conductive sheet 38 extends from the contact surface with the cooling circuit portion 34 toward the smoke exhaust portion 24 of the battery cell 20.

Description

Technical Field

[0001] The present invention relates to a battery structure.

Background Art

[0002] The following Patent Document 1 discloses an invention related to a battery pack. In this battery pack, a part of the bottom of the battery case that supports the battery cells is recessed downward of the battery pack, and this part can be used as a flow path for the gas discharged from the battery cells. Conventionally, a battery module in which a plurality of battery cells, which are rechargeable secondary batteries, are combined and modularized is widely known. It is known that various gases are generated inside the battery cells during charging / discharging or high-temperature holding processes. The battery cells are provided with safety valves for discharging such gases to the outside of the battery cells. Further, the battery module is provided with a smoke exhaust duct for guiding the gas discharged from the safety valve to the outside of the module. The smoke exhaust duct is arranged near the safety valve and is a passage that opens to the safety valve side. The gas discharged from the safety valve flows into the smoke exhaust duct through this opening.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in the above prior art, although the bottom of the battery case is cooled by a cooler, it is difficult for this cooler to cool the above flow path, and there is room for improvement in terms of cooling the above flow path and thus the gas discharged from the battery cells in the above prior art.

[0005] This disclosure aims to provide a battery structure that can cool the gas emitted from the battery cell, taking the above facts into consideration. [Means for solving the problem]

[0006] The battery structure according to the first embodiment comprises a battery case that houses a plurality of battery cells arranged in the arrangement direction and supports the battery cells at its bottom; a cooling circuit section that is positioned along the lower surface opposite to the battery cells at the bottom, and is positioned so as to not overlap with a smoke exhaust section provided on the bottom side of the battery cells when viewed from the height direction of the battery cells, and is capable of cooling the battery cells; and a heat conductive sheet that is interposed between the lower surface and the cooling circuit section, with a portion extending from the contact surface with the cooling circuit section toward the smoke exhaust section.

[0007] According to the battery structure of the first embodiment, a plurality of battery cells arranged in the arrangement direction are housed in a battery case, and these battery cells can be supported at the bottom of the battery case.

[0008] Furthermore, in this embodiment, a cooling circuit is arranged along the lower surface of the battery case opposite to the battery cell at the bottom, and the battery cell can be cooled using this cooling circuit.

[0009] Furthermore, in this embodiment, a smoke exhaust section is provided on the bottom side of the battery case of the battery cell, and the cooling circuit section is located in a position that does not overlap with the smoke exhaust section when viewed from the height direction of the battery cell. Therefore, in this embodiment, a gas exhaust section or flow path for gas containing smoke discharged from the battery cell can be provided at a position that overlaps with the smoke exhaust section when viewed from the height direction of the battery cell at the bottom of the battery case.

[0010] Incidentally, the portion of the battery case at the bottom that overlaps with the exhaust vent when viewed from the height direction of the battery cells is likely to become hot due to the gases discharged from the exhaust vent. However, as mentioned above, the cooling circuit is located in a position that does not overlap with the exhaust vent when viewed from the height direction of the battery cells, making it difficult to cool the portion of the battery case at the bottom that becomes hot due to the gases from the battery cells with the cooling circuit.

[0011] In this embodiment, a thermal conductive sheet is interposed between the lower surface of the bottom of the battery case and the cooling circuit section, and a portion of this thermal conductive sheet extends from the contact surface with the cooling circuit section toward the smoke exhaust section of the battery cell. Therefore, in this embodiment, the portion of the bottom of the battery case that overlaps with the smoke exhaust section when viewed from the height direction of the battery cell, that is, the portion of the bottom that comes into contact with the gas from the battery cell, can be cooled by the cooling circuit section via the thermal conductive sheet.

[0012] The battery structure according to the second embodiment is configured such that, in the battery structure according to the first embodiment, the bottom portion includes a support wall portion that supports the battery cells and a smoke exhaust passage portion that overlaps with the smoke exhaust portion when viewed from the height direction and extends in the arrangement direction, and into which gas from the smoke exhaust portion can flow, and the heat conductive sheet is in contact with the smoke exhaust passage portion.

[0013] According to the battery structure of the second embodiment, the bottom of the battery case is configured to include a support wall and a smoke exhaust channel. The support wall supports the battery cells, and the smoke exhaust channel overlaps with the smoke exhaust section of the battery cells when viewed from the height direction of the battery cells, extends in the direction of the arrangement of the battery cells, and allows gas from the smoke exhaust section to flow into it. Therefore, in this embodiment, a flow path for gas discharged from the battery cells can be secured on the lower side of the battery cells in the height direction of the smoke exhaust section.

[0014] Furthermore, in this embodiment, the heat conductive sheet is in contact with the flue gas flow path, and the flue gas flow path can be cooled by the cooling circuit via the heat conductive sheet. [Effects of the Invention]

[0015] As explained above, the battery structure according to this disclosure has the excellent effect of being able to cool the gas discharged from the battery cell. [Brief explanation of the drawing]

[0016] [Figure 1] This is a schematic plan view showing the configuration of a battery to which the battery structure according to this embodiment is applied. [Figure 2] This is a schematic cross-sectional view showing the configuration of a battery to which the battery structure according to this embodiment is applied (a cross-sectional view showing the state when cut along line 2-2 in Figure 1). [Modes for carrying out the invention]

[0017] An example of a battery structure according to this disclosure will be described below with reference to Figures 1 and 2. The battery pack 10 to which the battery heat insulation structure according to this embodiment is applied can be installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric vehicles.

[0018] First, we will describe the general configuration of the vehicle in which the battery pack 10 is installed. In each diagram, arrows FR indicate the front of the vehicle, arrows UP indicate the top of the vehicle, and arrows LH indicate the left side in the vehicle width direction.

[0019] The vehicle body comprises an aluminum die-cast front part (not shown) that constitutes the front portion of the vehicle, a center part (not shown) that constitutes the center of the vehicle in the longitudinal direction and includes a battery pack 10 and a frame-shaped center frame (not shown) that holds the battery pack 10 in plan view, and an aluminum die-cast rear part (not shown) that constitutes the rear portion of the vehicle. The front part is equipped with a power unit (not shown) including a motor, and the vehicle moves when this power unit is driven by electricity supplied from the battery pack 10.

[0020] As shown in FIG. 1, the battery pack 10 includes a battery case 12 constituting its outer shell and a plurality of battery modules 14 housed in the battery case 12.

[0021] The battery case 12 is mainly made of an aluminum alloy and includes a case upper 16 constituting the upper part of the vehicle and a case lower 18 constituting the lower part of the vehicle, as also shown in FIG. 2.

[0022] Inside the battery case 12, a plurality of battery modules 14 are arranged on the upper side of the vehicle of the bottom wall portion 18A as the bottom of the case lower 18, with the longitudinal direction being the vehicle front-rear direction and with a predetermined interval in the vehicle width direction with respect to each other.

[0023] The battery module 14 includes a plurality of battery cells 20. This battery cell 20 includes a cell case portion 22 that constitutes its outer shell and has a flat rectangular parallelepiped shape, and an electrode body (not shown) disposed inside the cell case portion 22.

[0024] In addition, a smoke exhaust portion 24 is provided at the center of the lower wall portion 22A that constitutes the lower part of the vehicle of the cell case portion 22. This smoke exhaust portion 24 is opened when the internal pressure of the battery cell 20 becomes a certain level or more, and serves as a valve that discharges the gas containing the smoke accumulated in the battery cell 20 to the outside.

[0025] The battery cells 20 configured as described above are arranged in a plurality of rows in the vehicle front-rear direction with their thickness direction being the vehicle front-rear direction. That is, in this embodiment, the arrangement direction of the battery cells 20 and the longitudinal direction of the battery module 14 are the same.

[0026] On the other hand, the bottom wall portion 18A of the case lower 18 includes a bulging portion 26, a smoke exhaust flow path portion 28, and an installation wall portion 30 that are convex upward in the vehicle and extend in the vehicle front-rear direction and are used to support the battery cells 20.

[0027] More specifically, the bulging portions 26 are arranged in pairs on each side of the underside of the vehicle in the width direction of the battery cell 20. These bulging portions 26 constitute the upper side of the vehicle and include a support wall portion 26A that supports the battery cell 20 from the underside of the vehicle, with its thickness direction being in the vehicle height direction. The cross-sectional shape viewed from the front-rear direction of the vehicle is U-shaped, opening to the underside of the vehicle and widening from the upper side to the lower side of the vehicle.

[0028] Furthermore, a thermal conductive sheet 32 ​​is interposed between the upper surface of the support wall 26A and the battery cell 20, and a cooling circuit 34 is positioned on the lower surface of a portion of the support wall 26A, i.e., the bottom wall 18A, as will be described later.

[0029] The exhaust gas flow path section 28 has a thickness direction that is in the direction of the vehicle height and includes a bottom section 28A that connects the pair of bulging sections 26 and a part of the bulging sections 26. When viewed from the front-rear direction of the vehicle, the cross-sectional shape is U-shaped, opening to the upper side of the vehicle and widening from the lower side to the upper side of the vehicle.

[0030] This exhaust gas passage section 28 extends in the longitudinal direction of the vehicle and is positioned to overlap with the exhaust gas section 24 when viewed from the vehicle height direction, i.e., the height direction of the battery cell 20, allowing gas (exhaust gas) from the exhaust gas section 24 to flow into it.

[0031] Furthermore, a through-hole (not shown) is formed in the bottom portion 28A, and this through-hole is sealed with a molten sheet (not shown) that melts at a predetermined temperature. In other words, in this embodiment, when the gas discharged from the battery cell 20 is above a predetermined temperature, this molten sheet melts, and this gas is discharged to the outside of the battery case 12.

[0032] The mounting wall 30 connects adjacent bulging portions 26 in the vehicle width direction between adjacent battery modules 14 in the vehicle width direction, and extends in the vehicle front-rear direction with its thickness direction being the vehicle height direction. A front-rear member portion 36 is provided on the upper surface of the mounting wall 30.

[0033] The front-rear member portion 36 has a hat-like cross-sectional shape when viewed from the front-rear direction of the vehicle, with the underside of the vehicle open, and its pair of flange portions 36A are joined to the installation wall portion 30 by a joint (not shown) such as welding.

[0034] Furthermore, cell holding portions (not shown) are provided on one side and the other side in the vehicle width direction of the front-rear member portion 36, and these cell holding portions have an L-shaped cross-section when viewed from the front-rear direction of the vehicle, and the battery cells 20 are held in these cell holding portions.

[0035] On the other hand, the cooling circuit section 34 extends in the longitudinal direction of the vehicle and is arranged in multiple (for example, three) sections in the width direction of the vehicle, and includes a flow path section 34A through which the refrigerant flows. The battery cells 20 are cooled by heat exchange between the refrigerant flowing through the flow path section 34A and the battery cells 20. A heat conductive sheet 38 is interposed between the lower surface of the support wall section 26A and the upper surface of the cooling circuit section 34.

[0036] The heat conductive sheet 38 extends from the contact surface with the cooling circuit section 34 toward the exhaust section 24, and is in contact with a part of the exhaust flow path section 28.

[0037] (Operation and effects of this embodiment) Next, the operation and effects of this embodiment will be described.

[0038] In this embodiment, as shown in Figure 1, a plurality of battery cells 20 arranged in the front-rear direction of the vehicle are housed in a battery case 12, and these battery cells 20 can be supported by the bottom wall portion 18A of the battery case 12.

[0039] Furthermore, in this embodiment, as shown in Figure 2, a cooling circuit section 34 is arranged along the lower surface of the bottom wall 18A of the battery case 12 opposite to the battery cell 20, and the battery cell 20 can be cooled using this cooling circuit section 34.

[0040] Furthermore, in this embodiment, a smoke exhaust section 24 is provided on the bottom wall portion 18A side of the battery cell 20, and the cooling circuit portion 34 is located in a position that does not overlap with the smoke exhaust section 24 when viewed from the vehicle height direction. Therefore, in this embodiment, a gas exhaust section or flow path for gas discharged from the battery cell 20 can be provided in the bottom wall portion 18A at a position that overlaps with the smoke exhaust section 24 when viewed from the vehicle height direction.

[0041] Incidentally, the portion of the bottom wall 18A of the battery case 12 that overlaps with the exhaust pipe 24 when viewed from the vehicle height direction is likely to become hot due to the gas discharged from the exhaust pipe 24. However, as mentioned above, the cooling circuit 34 is located in a position that does not overlap with the exhaust pipe 24 when viewed from the vehicle height direction, making it difficult for the cooling circuit 34 to cool the portion of the bottom wall 18A that becomes hot due to the gas from the battery cells 20.

[0042] In this embodiment, a thermal conductive sheet 38 is interposed between the lower surface of the bottom wall portion 18A of the battery case 12 and the cooling circuit portion 34. A portion of this thermal conductive sheet 38 extends from the contact surface with the cooling circuit portion 34 toward the exhaust portion 24 of the battery cell 20. Therefore, in this embodiment, the portion of the bottom wall portion 18A that overlaps with the exhaust portion 24 when viewed from the vehicle height direction, that is, the portion of the bottom wall portion 18A that comes into contact with the gas from the battery cell 20, can be cooled by the cooling circuit portion 34 via the thermal conductive sheet 38.

[0043] Furthermore, in this embodiment, the bottom wall portion 18A of the battery case 12 is configured to include a support wall portion 26A and a smoke exhaust passage portion 28. The support wall portion 26A supports the battery cell 20, and the smoke exhaust passage portion 28 overlaps with the smoke exhaust portion 24 of the battery cell 20 when viewed from the vehicle height direction, extends in the vehicle's longitudinal direction, and allows gas from the smoke exhaust portion 24 to flow in. Therefore, in this embodiment, a passage for gas discharged from the battery cell 20 can be secured on the lower side of the smoke exhaust portion 24 in the vehicle height direction.

[0044] Furthermore, in this embodiment, the heat conductive sheet 38 is in contact with the exhaust gas flow path section 28, and the exhaust gas flow path section 28 can be cooled by the cooling circuit section 34 via the heat conductive sheet 38.

[0045] As described above, in this embodiment, the gas discharged from the battery cell 20 can be cooled.

[0046] <Supplementary explanation of the above embodiment> In the embodiment described above, the battery module 14 was composed of multiple battery cells 20, but the battery cells 20 may be individually attached to the battery case 12 depending on the specifications of the battery pack 10, etc.

[0047] Furthermore, in this embodiment, the arrangement direction of the battery cells 20 was set to the vehicle's longitudinal direction, but depending on the specifications of the battery pack 10, the arrangement direction of the battery cells 20 may be set to a direction other than the vehicle's longitudinal direction, such as the vehicle's width direction. [Explanation of Symbols]

[0048] 12 Battery Case 18A Bottom wall (bottom) 20 battery cells 24 Smoke exhaust section 26A Support wall section 28 Smoke exhaust flow path 34 Cooling circuit section 38 Thermal conductive sheet

Claims

1. A battery case that houses multiple battery cells arranged in the direction of arrangement and supports the battery cells at the bottom, A cooling circuit section is provided which is positioned along the lower surface opposite to the battery cell at the bottom, and which does not overlap with the smoke exhaust section provided on the bottom side of the battery cell when viewed from the height direction of the battery cell, and which is capable of cooling the battery cell. A heat conductive sheet interposed between the lower surface and the cooling circuit portion, with a portion extending from the contact surface with the cooling circuit portion toward the smoke exhaust portion, A battery structure equipped with this feature.

2. The bottom portion is configured to include a support wall portion that supports the battery cell, and a smoke exhaust channel portion that overlaps with the smoke exhaust portion when viewed from the height direction and extends in the arrangement direction, and into which smoke from the smoke exhaust portion can flow. The heat conductive sheet is in contact with the exhaust gas flow path section. The battery structure according to claim 1.

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