Vehicle battery cooling system

Abstract

This invention provides a vehicle battery cooling system that can shorten battery charging time by reducing variations in the flow rate of the coolant when the battery temperature rises in a low-temperature environment. [Solution] A vehicle battery cooling system 10 for cooling or heating a battery 90 mounted on a vehicle, comprising a coolant circuit 20 for circulating coolant, the coolant circuit 20 comprising a heat exchanger 30 for cooling or heating the battery 90, the heat exchanger 30 comprising a plurality of flow paths 31 for cooling or heating the battery 90, and a manifold pipe 32 on one side from which the plurality of flow paths 31 branch off, the manifold pipe 32 on one side having a plurality of flow paths 31 connected in a line from the base end to the tip end, the manifold pipe 32 on one side being gradually expanded in diameter in the direction in which the coolant flows when heating the battery 90, and the expansion angle of the manifold pipe 32 on one side being 10° or more and 60° or less.

Description

Technical Field

[0001] The present disclosure relates to a vehicle battery cooling system for cooling or heating a battery mounted on a vehicle.

Background Art

[0002] For example, an electric vehicle as a vehicle has a battery mounted thereon. The battery needs to be operated within an appropriate temperature range. For example, since the battery generates a large amount of heat during operation, it is necessary to lower the temperature within the operating range. In this case, the vehicle battery cooling system cools the battery by circulating coolant cooled by a chiller through a heat exchanger close to the battery.

[0003] On the other hand, for example, when the battery is charged (especially rapidly charged) in a low-temperature environment in a cold region, the charging amount of the battery may be limited because the battery temperature is low. In this case, the vehicle battery cooling system raises the temperature of the battery by circulating coolant heated by a heater through a heat exchanger close to the battery.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, the viscosity of the coolant may change depending on the temperature of the coolant. Therefore, for example, when the heat exchanger is designed such that the flow rate distribution in each flow path becomes equal during cooling, the viscosity of the coolant may change during heating, and the flow rate may vary in each flow path. In this case, the battery (cell) close to the flow path with a low flow rate of the heat exchanger cannot be sufficiently heated. And in this case, since the battery cannot be sufficiently heated, the charging time of the battery becomes long.

[0006] Therefore, the present invention aims to provide a vehicle battery cooling system that can shorten the battery charging time by reducing variations in the flow rate of the coolant when the battery temperature rises in a low-temperature environment. [Means for solving the problem]

[0007] The vehicle battery cooling system according to the present invention is a vehicle battery cooling system for cooling or heating a battery mounted on a vehicle, and has a coolant circuit for circulating coolant, the coolant circuit having a heat exchanger for cooling or heating the battery, a pump that discharges coolant to circulate the coolant to the heat exchanger and can switch the direction of circulation of the coolant in the heat exchanger depending on whether the battery is being cooled or heated, a chiller for cooling the coolant, and a heater for heating the coolant, the heat exchanger having a plurality of flow paths for cooling or heating the battery, a manifold pipe on one side from which the plurality of flow paths branch, and a manifold pipe on the other side from which the plurality of flow paths branch, the manifold pipe on one side having a plurality of flow paths connected in a line from the base end to the tip end, the manifold pipe on one side is gradually widened in the direction in which the coolant flows when the battery is being heated, and the widening angle of the manifold pipe on one side is 10° or more and 60° or less. [Effects of the Invention]

[0008] According to the vehicle battery cooling system of the present invention, the battery charging time can be shortened by reducing variations in the flow rate of the coolant when the battery temperature rises in a low-temperature environment. [Brief explanation of the drawing]

[0009] [Figure 1] This is a circuit diagram showing a battery cooling system, which is an example of an embodiment. [Figure 2] This is a schematic diagram illustrating the flow rate variation of a battery cooling system, which is an example of an embodiment. [Figure 3] This is a schematic diagram illustrating the flow rate variation in a conventional battery cooling system. [Modes for carrying out the invention]

[0010] An example of an embodiment of the present invention will be described in detail below. In the following description, specific shapes, materials, directions, numerical values, etc., are examples provided to facilitate understanding of the present invention and can be appropriately modified according to the application, purpose, specifications, etc.

[0011] [Battery cooling system] An example of an embodiment, a battery cooling system 10, will be described using Figure 1.

[0012] The battery cooling system 10 is a system for cooling or heating the battery 90, which functions as a battery. As will be described in detail later, the battery cooling system 10 can reduce variations in the flow rate of the cooling liquid when the battery heats up in a low-temperature environment, thereby shortening the charging time of the battery 90.

[0013] The battery 90 is mounted on the vehicle. The vehicle is, for example, an electric vehicle (BEV (Battery Electric Vehicle)), which drives itself by rotating a motor using the electricity charged in the battery 90. Although the vehicle in this embodiment is an electric vehicle, the present invention is not limited to this. The vehicle of the present invention may be a hybrid vehicle (HEV (Hybrid Electric Vehicle)) or a plug-in hybrid vehicle (PHEV (Plug-in Hybrid Electric Vehicle)).

[0014] The battery cooling system 10 includes a coolant circuit 20 for circulating coolant (details of which will be described later), and a control device 50 for controlling the operation of the pump 21, chiller 22, and heater 23.

[0015] Coolant is preferably used as the coolant. Coolant is also called antifreeze and may be referred to as LLC (Long Life Coolant) or SLLC (Super Long Life Coolant). Coolant is mainly composed of ethylene glycol and contains rust inhibitors, dyes, etc.

[0016] The cooling fluid circuit 20 comprises a heat exchanger 30, a pump 21, a chiller 22, and a heater 23, each of which will be described in detail later.

[0017] The heat exchanger 30 is positioned close to the battery 90. Here, "close" means at a distance where heat exchange can occur between the heat exchanger 30 and the battery 90. The heat exchanger 30 cools the battery 90 or raises its temperature. More specifically, the heat exchanger 30 cools the battery 90 by circulating a coolant cooled by the chiller 22, or raises its temperature by circulating a coolant heated by the heater 23. Further details about the heat exchanger 30 will be described later.

[0018] Pump 21 discharges coolant to circulate it through the heat exchanger 30, and can switch the direction of coolant circulation in the heat exchanger 30 depending on whether it is cooling the battery 90 or raising its temperature. Pump 21 is driven by a motor. Pump 21 can switch the direction of coolant discharge and thus the direction of coolant circulation, for example, by reversing the motor's drive current. Pump 21 is connected to the control device 50.

[0019] The chiller 22 cools the coolant passing through the coolant circuit 20. Preferably, the chiller 22 has an adjustable cooling capacity. The chiller 22 may also be a heat exchanger cooled by another refrigerant, for example.

[0020] The heater 23 heats the coolant passing through the coolant circuit 20. The heater 23 preferably has an adjustable heating capacity. The heater 23 may be, for example, an electric heater. Also, the heater 23 may be a heat exchanger heated by other refrigerant.

[0021] The control device 50 is connected to the pump 21, the chiller 22, and the heater 23, and controls the operations of the pump 21, the chiller 22, and the heater 23. The control device 50 has a CPU (Central Processing Unit) as an arithmetic processing unit and a storage unit such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and performs signal processing according to a program stored in advance in the ROM while using the temporary storage function of the RAM.

[0022] When cooling the battery 90, for example, the control device 50 switches the pump 21 to the positive circulation direction (details will be described later) and turns on the chiller 22. When heating the battery 90, for example, the control device 50 switches the pump 21 to the reverse circulation direction (details will be described later) and turns on the heater 23.

[0023] [Heat Exchanger] Using FIGS. 1 and 2, a heat exchanger 30 which is an example of an embodiment will be described.

[0024] As described above, the heat exchanger 30 is arranged close to the battery 90 to cool the battery 90 or heat up the battery 90. According to the heat exchanger 30, although details will be described later, it is possible to reduce the variation in the coolant flow rate during battery heating in a low-temperature environment.

[0025] In the heat exchanger 30, when cooling the battery 90, the coolant is circulated in the positive circulation direction. The positive circulation direction is the circulation direction from the collective pipe 32 on one side (to be described later) through the plurality of flow paths 31 and toward the collective pipe 33 on the other side.

[0026] In the heat exchanger 30, when raising the temperature of the battery 90, the coolant is circulated in the reverse direction. The reverse circulation direction is the direction in which the coolant flows from the other side's manifold pipe 33, which will be described later, through multiple flow paths 31, towards the one side's manifold pipe 32.

[0027] The heat exchanger 30 has a plurality of flow paths 31, a manifold pipe 32 on one side, and a manifold pipe 33 on the other side, each of which will be described in detail later. The plurality of flow paths 31 are numbered 31A, ..., 31H from the base end (the side closer to the pump 21) to the tip end.

[0028] Multiple flow paths 31 are arranged at equal intervals along one direction of the battery 90. This allows the battery 90 to be cooled or heated evenly. One side of each of the multiple flow paths 31 is connected to the manifold piping 32 on one side. The other side of each of the multiple flow paths 31 is connected to the manifold piping 33 on the other side.

[0029] Multiple flow paths 31 branch off from one side of the manifold pipe 32. Multiple flow paths 31 are connected in a row to the manifold pipe 32, running from the base end to the tip end. When cooling the battery 90, coolant flows through the manifold pipe 32 from the base end (the side closer to the pump 21) to the tip end. When raising the temperature of the battery 90, coolant flows through the manifold pipe 32 from the tip end to the base end.

[0030] The manifold pipe 32 is formed with a gradually increasing diameter from the tip end to the base end. Preferably, the manifold pipe 32 has a gradually increasing diameter along its entire length from the tip end to the base end. In other words, when cooling the battery 90, the manifold pipe 32 gradually decreases in diameter in the direction of coolant flow. That is, when raising the temperature of the battery 90, the manifold pipe 32 gradually increases in diameter in the direction of coolant flow.

[0031] The diameter expansion angle of the manifold pipe 32 is 10° or more and 60° or less, and preferably 20° or more and 30° or less. The diameter expansion angle refers to the angle of the expanded pipe diameter relative to the original straight pipe diameter.

[0032] Multiple flow paths 31 branch off from the other side of the manifold pipe 33. Multiple flow paths 31 are connected in a row to the manifold pipe 33, from the base end to the tip end. When cooling the battery 90, coolant flows through the manifold pipe 33 from the tip end to the base end (the side closer to the pump 21). When raising the temperature of the battery 90, coolant flows through the manifold pipe 33 from the base end to the tip end.

[0033] [Coolant circulation] Using Figures 2 and 3, we will explain the circulation of the coolant in a heat exchanger 30, which is an example of an embodiment.

[0034] As shown in Figure 3, first, the circulation of the coolant in the conventional heat exchanger 130 will be described. In the conventional heat exchanger 130, one of the manifold pipes 132 is not formed with a gradually increasing diameter from the tip to the base. Also, the circulation direction of the heat exchanger 130 is the same whether the battery 90 is being cooled or the battery 90 is being heated. The other configurations are the same as those of the heat exchanger 30 in this embodiment.

[0035] Here, the viscosity of the coolant may change with temperature. In the heat exchanger 130, the flow rate distribution in each channel 131 is normally equal when cooling the battery 90 (see the graph during cooling in Figure 3). However, when raising the temperature of the battery 90, the viscosity of the coolant changes as the temperature rises, which may cause variations in the flow rate in each channel 131 (see the graph during temperature rise in Figure 3).

[0036] In this case, the cells of the battery 90 adjacent to the flow path with low flow rate in the heat exchanger 130 cannot be sufficiently heated. As a result, the charging time of the battery 90 is prolonged because it cannot be sufficiently heated.

[0037] As shown again in Figure 2, in the heat exchanger 30 of this embodiment, as described above, one of the manifold pipes 32 is formed with a gradually increasing diameter from the tip end to the base end. Also, the circulation direction of the heat exchanger 30 is reversed when cooling the battery 90 and when raising the temperature of the battery 90. The heat exchanger 30 is designed so that flow rate fluctuations do not occur when cooling the battery 90.

[0038] With the above configuration, when cooling the battery 90 in the heat exchanger 30, as described above, the coolant flows from the manifold piping 32 on one side through multiple flow paths 31 to the manifold piping 33 on the other side.

[0039] As described above, one of the manifold pipes 32 is formed with a gradually increasing diameter from the tip end to the base end, and gradually decreasing in diameter in the direction of coolant flow, but no particular pressure loss occurs. Therefore, since each flow path 31 is designed to cool the battery 90 without variations in flow rate, there are no variations in flow rate in each flow path 31.

[0040] On the other hand, when cooling the battery 90 in the heat exchanger 30, as described above, the coolant flows from the manifold piping 33 on the other side through multiple flow paths 31 to the manifold piping 32 on the one side.

[0041] As described above, one of the manifold pipes 32 is formed with a gradually increasing diameter from the tip end to the base end, and the diameter gradually increases in the direction of coolant flow. In this case, vortices are generated due to flow separation, and energy is lost, resulting in pressure loss. Therefore, the coolant flows less easily towards the base end flow path 31A. This reduces the variation in flow rate in each flow path 31. As a result, the battery 90 can be sufficiently heated. This shortens the charging time of the battery 90.

[0042] It should be noted that the present invention is not limited to the embodiments and their modifications described above, and various changes and improvements are possible within the scope of the claims of this application. [Explanation of Symbols]

[0043] 10 Battery cooling system, 20 Coolant circuit, 21 Pump, 22 Chiller, 22 Heater, 23 Chiller, 30, 130 Heat exchanger, 31, 131 Flow path, 32, 132 Manifold piping, 33, 133 Manifold piping, 50 Control device, 90 Battery

Claims

[Claim 1] A vehicle battery cooling system for cooling or heating batteries mounted on a vehicle, It has a coolant circuit that circulates the coolant, The cooling fluid circuit comprises a heat exchanger for cooling or heating the battery, a pump that discharges the cooling fluid to circulate it through the heat exchanger and can switch the circulation direction of the cooling fluid in the heat exchanger depending on whether the battery is being cooled or heated, a chiller for cooling the cooling fluid, and a heater for heating the cooling fluid. The heat exchanger has a plurality of flow paths for cooling or heating the battery, a manifold pipe on one side from which the plurality of flow paths branch off, and a manifold pipe on the other side from which the plurality of flow paths branch off. Multiple flow paths are connected in a row to the manifold piping on one side, from the base end to the tip end. The manifold piping on one side is gradually widened in the direction through which the coolant flows when the battery is heated. The diameter expansion angle of the manifold piping on one side is 10° or more and 60° or less. Vehicle battery cooling system.

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