Cooling system

Abstract

This cooling system comprises a motor, a power converter, a flow passage for causing a cooling fluid to circulate to the motor and the power converter, and a switching valve for switching a flow passage through which the cooling fluid circulates. The flow passage includes a first flow passage and a second flow passage which branch into two branches and flow together again, the motor being disposed in the first flow passage and the power converter being disposed in the second flow passage. The switching valve is disposed in a location in which the flow passage branches to the first flow passage and the second flow passage, and is configured to be capable of switching the flow passage through which the cooling fluid circulates between the first flow passage and the second flow passage.

Description

Technical Field

[0001] The present disclosure relates to a cooling system. Background Art

[0002] In recent years, automobiles equipped with a motor as a traveling drive source (hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), etc.) have become widespread. These automobiles (hereinafter collectively referred to as "electric vehicles") are provided with a battery for driving a motor. In electric vehicles, there are many devices that require cooling, such as motors (including internal combustion engines such as engines), batteries, air conditioners, and ECUs, so a cooling circuit that circulates cooling water and refrigerant is configured to cool these devices. However, these devices may individually have different appropriate operating temperatures. In such cases, in order to change the temperature of the circulating cooling water or refrigerant for each device having different operating temperatures, heat is exchanged through heat exchangers such as chillers and water-cooled condensers, and temperature control of the cooling water and refrigerant is performed.

[0003] The cooling circuit disclosed in Patent Document 1 includes a plurality of control modes that control a first pump, a second pump, a first switching valve, and a second switching valve, and change the flow of cooling water in a first cooling water passage, a second cooling water passage, a third cooling water passage, a fourth cooling water passage, and a bypass passage according to the outside air temperature or the battery water temperature. Among these, in the second cooling water passage, an inverter cooling unit and a motor generator cooling unit are arranged in series in this order from the upstream side with respect to the flow direction of the cooling water. Prior Art Literature Patent Literature

[0004] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2019-023059 [Overview of the project] [Problems that the invention aims to solve]

[0005] In the second cooling water flow path of the cooling circuit disclosed in Patent Document 1, the cooling water is heated by heat exchange with the inverter and the motor generator. In this cooling circuit, the inverter cooling section is located upstream of the cooling water flow direction in the second cooling water flow path, and the motor generator cooling section is located downstream. Therefore, the cooling water is first heated by absorbing heat from the inverter in the inverter cooling section, and then heated by absorbing heat from the motor generator in the motor generator cooling section. As a result, the amount of heat absorbed by the motor generator in the motor generator cooling section decreases because the cooling water absorbs heat from the inverter before absorbing heat from the motor generator.

[0006] This disclosure has been made in view of the above-mentioned problems, and its purpose is to provide a cooling system in which the cooling fluid can efficiently absorb the heat generated by the motor. [Means for solving the problem]

[0007] One embodiment of the cooling system according to the present disclosure comprises a motor, a power converter, a flow path for circulating a cooling fluid to the motor and the power converter, and a switching valve for switching the flow path through which the cooling fluid flows, wherein the flow path includes a first flow path and a second flow path that branch into two and then rejoin, the motor is located in the first flow path, the power converter is located in the second flow path, and the switching valve is located at the point where the flow path branches into the first flow path and the second flow path, and is configured to switch the flow path through which the cooling fluid flows between the first flow path and the second flow path.

[0008] In the cooling system of this embodiment, the motor is located in the first flow path, and the power converter is located in the second flow path. A switching valve is located at the point where the flow path branches into the first and second flow paths, and the flow path through which the cooling fluid flows can be switched between the first and second flow paths by the switching valve. As a result, the motor and the power converter are arranged in parallel with respect to the flow path, and the problem of the amount of heat absorbed by the motor being reduced by the cooling fluid absorbing heat from the power converter before absorbing heat from the motor does not occur. This makes it possible to provide a cooling system in which the cooling fluid can efficiently absorb the heat generated by the motor. [Brief explanation of the drawing]

[0009] [Figure 1] This is a configuration diagram showing an example of control for the cooling system according to this embodiment. [Figure 2] This is a flowchart illustrating the operation of the cooling system. [Figure 3] This is a configuration diagram showing an example of control for the cooling system according to this embodiment. [Figure 4] This is a configuration diagram showing an example of control for the cooling system according to this embodiment. [Figure 5] This is a configuration diagram showing an example of control for the cooling system according to this embodiment. [Modes for carrying out the invention]

[0010] The embodiments of the cooling system relating to this disclosure will be described in detail below with reference to the drawings. The embodiments described below are illustrative examples for illustrating this disclosure and do not limit this disclosure to these embodiments only. Therefore, this disclosure can be implemented in various forms without departing from its essence.

[0011] [Cooling system configuration] The cooling system A according to this embodiment is used in automobiles equipped with a motor as a driving source (hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), etc.). Hereinafter, these automobiles will be collectively referred to as electric vehicles. As shown in Figure 1, the cooling system A is composed of a motor cooling circuit 1 through which a cooling fluid flows, a battery cooling circuit 2, and a four-way valve 3. The four-way valve 3 switches between a connected state in which the motor cooling circuit 1 and the battery cooling circuit 2 are connected, and an independent state in which the motor cooling circuit 1 and the battery cooling circuit 2 are disconnected. The four-way valve 3 shown in Figure 1 represents the independent state in which the motor cooling circuit 1 and the battery cooling circuit 2 are disconnected, while the four-way valve 3 shown in Figures 3 to 5 represents the connected state in which the motor cooling circuit 1 and the battery cooling circuit 2 are connected.

[0012] The motor cooling circuit 1 includes a motor pump 11, which is composed of a water pump or the like, for pressurizing the cooling fluid; a motor 12, which is the drive source of the electric vehicle; an inverter 13 (an example of a power converter) that supplies power to the motor 12; a radiator 14 for cooling the cooling fluid; a motor flow path 16 (an example of a flow path) for circulating the cooling fluid through these components; and a switching valve 15 for switching the motor flow path 16. The cooling fluid is a cooling water such as long-life coolant (LLC), an insulating oil such as paraffin, or a refrigerant such as hydrofluorocarbon (HFC) or hydrofluoroolefin (HFO). In this embodiment, it is preferable to use a cooling water such as long-life coolant (LLC) or a liquid with high electrical insulation properties such as a fluorine-based inert liquid, but a cooling liquid composed of cooling water or insulating oil may also be used. The power converter also includes, for example, a DC-DC converter or an OBC (On-Board Charger).

[0013] The motor flow path 16 includes a first motor flow path 16a (an example of the first flow path) and a second motor flow path 16b (an example of the second flow path), which branch into two and then rejoin. The motor 12 is cooled by the cooling fluid flowing through the first motor flow path 16a, and the inverter 13 is cooled by the cooling fluid flowing through the second motor flow path 16b. The switching valve 15 is located at the point where the motor flow path 16 branches into the first motor flow path 16a and the second motor flow path 16b. The switching valve 15 is configured to allow the cooling fluid to flow in four ways by switching the valve body: flowing only through the first motor flow path 16a, flowing only through the second motor flow path 16b, flowing through both the first and second motor flow paths 16b, and not flowing through either the first or second motor flow path 16b. Alternatively, the switching valve 15 may be configured to allow three ways of switching by eliminating the case where the fluid does not flow through either the first or second motor flow path 16b.

[0014] Next, the operation of the motor cooling circuit 1 when the motor cooling circuit 1 and the battery cooling circuit 2 are in an independent state due to the four-way valve 3 will be described. The independent state can be achieved by rotating the valve body of the four-way valve 3 from the state shown in Figure 3 to the state shown in Figure 1 by 90 degrees. The cooling fluid pumped from the motor pump 11 flows through the motor passage 16 and flows into the switching valve 15. Since the motor pump 11 is operating, the switching valve 15 is switched to one of the following states: to allow the cooling fluid to flow only through the first motor passage 16a, to allow it to flow only through the second motor passage 16b, or to allow it to flow through both the first motor passage 16a and the second motor passage 16b. The switching valve 15 shown in Figure 1 represents the state in which the cooling fluid flows through both the first motor passage 16a and the second motor passage 16b.

[0015] When the switching valve 15 is switched so that the cooling fluid flows only through the first motor passage 16a, the cooling fluid flowing into the switching valve 15 flows only through the first motor passage 16a and is heated by absorbing the heat generated by the motor 12 (see Figure 4). When the switching valve 15 is switched so that the cooling fluid flows only through the second motor passage 16b, the cooling fluid flowing into the switching valve 15 flows only through the second motor passage 16b and is heated by absorbing the heat generated by the inverter 13 (see Figure 5). When the switching valve 15 is switched so that the cooling fluid flows through both the first motor passage 16a and the second motor passage 16b, the cooling fluid flowing into the switching valve 15 flows through both the first motor passage 16a and the second motor passage 16b and is heated by absorbing the heat generated by the motor 12 and the inverter 13 (see Figures 1 and 3). In either case, the heated cooling fluid, whose temperature has risen, flows through the motor passage 16 and into the radiator 14, where it is cooled and then returned to the motor pump 11.

[0016] Next, the battery cooling circuit 2 will be described. The battery cooling circuit 2 includes a battery pump 21, which consists of a water pump or the like, for pressurizing the cooling fluid; a battery 22, which supplies power to the inverter 13; a chiller 24 for cooling the cooling fluid; and a battery flow path 26 (an example of a flow path) for circulating the cooling fluid through these components. The battery flow path 26 of the battery cooling circuit 2 is configured to be switchable between a connected state and an independent state with respect to the motor flow path 16 of the motor cooling circuit 1 by switching the four-way valve 3.

[0017] Next, the operation of the battery cooling circuit 2 when the motor cooling circuit 1 and the battery cooling circuit 2 are in an independent state due to the four-way valve 3 will be explained. The cooling fluid pumped from the battery pump 21 flows through the battery passage 26 and into the battery 22. The cooling fluid absorbs the heat generated in the battery 22 and is heated. The heated cooling fluid, whose water temperature has risen, flows through the battery passage 26 and into the chiller 24, where it is cooled and then returned to the battery pump 21.

[0018] [Cooling system operation] Next, the operation of the cooling system A will be described with reference to FIG. 2. In this embodiment, the temperatures from T1 (first temperature) to T4 (fourth temperature) shown in FIG. 2 are set such that T1 < T2 < T4 < T3. In the following description, the operations of the motor pump 11, the motor 12, the inverter 13, the radiator 14, the switching valve 15, the battery pump 21, the battery 22, and the chiller 24 are controlled by an ECU (Electronic Control Unit), which is not shown. Further, the temperatures of the motor 12, the inverter 13, and the battery 22 are measured by temperature sensors (not shown), and the measurement results are configured to be input to the ECU. Note that the temperatures of the motor 12, the inverter 13, and the battery 22 may also be estimated from the temperature of the cooling fluid flowing through each of them respectively.

[0019] When the power switch of a stopped electric vehicle is pressed to start the motor 12 (step S1), the temperature sensor measures the temperature of the battery 22. If the temperature of the battery 22 exceeds the fourth temperature T4 (e.g., 35°C) (Yes in step S3), the four-way valve 3 is switched such that the motor cooling circuit 1 and the battery cooling circuit 2 are in an independent state. Then, the switching valve 15 is switched so that the cooling fluid flows through both the first motor flow path 16a and the second motor flow path 16b, and the chiller 24 is activated (step S17, see FIG. 1). The temperatures of the motor 12 and the inverter 13 immediately after startup are substantially the same as the temperature of the battery 22. When the temperature of the battery 22 exceeds the fourth temperature T4, the motor 12, the inverter 13, and the battery 22 need to be cooled, and the motor cooling circuit 1 and the battery cooling circuit 2 are switched to an independent state to cool these components to the maximum extent. That is, in the motor cooling circuit 1, the cooling fluid flows through both the first motor flow path 16a and the second motor flow path 16b, is heated by cooling the motor 12 and the inverter 13, and then is cooled by the radiator 14. Further, in the battery cooling circuit 2, the cooling fluid cools the battery 22, is heated, and then is cooled by the chiller 24. The state of step S17 is continued until the power switch of the electric vehicle is pressed again and the motor 12 stops (step S19).

[0020] When the temperature of battery 22 immediately after the start of motor 12 is equal to or lower than the fourth temperature T4 (No in step S3), and exceeds the first temperature T1 (e.g., 5°C, an example of a first predetermined temperature) (Yes in step S5), the four-way valve 3 is switched so that the motor cooling circuit 1 and the battery cooling circuit 2 are brought into a connected state. Then, the switching valve 15 is maintained such that the cooling fluid flows through both the first motor flow path 16a and the second motor flow path 16b, and the chiller 24 is stopped (step S15, see FIG. 3). When the motor cooling circuit 1 and the battery cooling circuit 2 are in a connected state, the cooling fluid flowing through the motor flow path 16 after the merging of the first motor flow path 16a and the second motor flow path 16b flows into the battery pump 21 disposed in the battery flow path 26 of the battery cooling circuit 2. Then, the cooling fluid flowing through the battery flow path 26 on the downstream side of the chiller 24 flows into the radiator 14 of the motor cooling circuit 1. Note that "stopping the chiller 24" means that the cooling fluid is not cooled by the chiller 24, and this is achieved, for example, by switching to a bypass flow path that bypasses the chiller 24.

[0021] When the temperature of the battery 22 exceeds the first temperature T1 and is equal to or lower than the fourth temperature T4, control is performed to warm up the battery 22 while cooling the motor 12 and the inverter 13. That is, in the motor cooling circuit 1, the cooling fluid flows through both the first motor flow path 16a and the second motor flow path 16b, and is heated by cooling the motor 12 and the inverter 13. The heated cooling fluid flows into the battery cooling circuit 2 and warms up the battery 22. The cooling fluid that has been cooled by warming up the battery 22 is not further cooled by the chiller 24, and is cooled only by the radiator 14. In this way, since the cooling fluid is not excessively cooled, the battery 22 can be warmed up while cooling the motor 12 and the inverter 13. The state of step S15 is continued until the battery 22 is warmed up to reach the fourth temperature T4. Then, when the temperature of the battery 22 exceeds the fourth temperature T4 (Yes in step S3), the motor cooling circuit 1 and the battery cooling circuit 2 are switched to the state of step S17.

[0022] If the temperature of the battery 22 immediately after starting the motor 12 is below the first temperature T1 (No. in step S5), the four-way valve 3 is switched to connect the motor cooling circuit 1 and the battery cooling circuit 2. The switching valve 15 is then switched so that the cooling fluid flows only through the first motor passage 16a, and the chiller 24 stops (step S7, see Figure 4).

[0023] When the temperature of the battery 22 is below the first temperature T1, the motor 12 is cooled while the battery 22 is warmed up. That is, in the motor cooling circuit 1, the cooling fluid flows only through the first motor flow path 16a and is heated by cooling the motor 12. In the second motor flow path 16b, the cooling fluid remains stagnant, so the inverter 13 is not cooled and generates its own heat. The cooling fluid heated by the motor 12 flows into the battery cooling circuit 2 and warms up the battery 22. The cooling fluid cooled by warming up the battery 22 is not further cooled by the chiller 24, but is cooled only by the radiator 14. As a result, the cooling fluid is not excessively cooled, so the motor 12 can be cooled while the battery 22 is warmed up. In addition, since the cooling fluid is heated using the self-heating of the motor 12, which has a large heat capacity, the temperature of the battery 22 can be raised quickly and warming up can be promoted.

[0024] As described above, if the temperature of the battery 22 is below the first temperature T1, the cooling fluid does not flow to the inverter 13, so if the motor 12 is driven continuously, the temperature of the inverter 13 rises. If the temperature of the inverter 13 is below the third temperature T3 (for example, 40 degrees, an example of a third predetermined temperature) (No in step S9), the process returns to step S5, and the temperature sensor measures the temperature of the battery 22. As long as the temperature of the battery 22 is below the first temperature T1 and the temperature of the inverter 13 is below the third temperature T3, the state in step S7 continues. If the temperature of the inverter 13 exceeds the third temperature T3 (Yes in step S9), the switching valve 15 is switched so that the cooling fluid flows only to the second motor flow path 16b (step S11, see Figure 5). That is, the cooling fluid in the first motor flow path 16a becomes stagnant. At this time, the motor cooling circuit 1 and the battery cooling circuit 2 are connected, and the chiller 24 is stopped.

[0025] As the cooling fluid flows through the inverter 13, the inverter 13 is cooled, and the temperature of the inverter 13 drops to below the third temperature T3. The state in step S11 continues until the temperature of the inverter 13 falls below the second temperature T2 (for example, 30 degrees, an example of a second predetermined temperature) (No in step S13). When the temperature of the inverter 13 falls below the second temperature T2 (Yes in step S13), the process returns to step S5, and the temperature of the battery 22 is measured. If the temperature of the battery 22 is still below the first temperature T1 (No in step S5), the switching valve 15 is switched again so that the cooling fluid flows only through the first motor flow path 16a, as shown in Figure 4, and step S7 is executed. This series of steps is repeated until the temperature of the battery 22 exceeds the first temperature T1. When the battery 22 exceeds the first temperature T1 (Yes in step S5), the motor cooling circuit 1 and the battery cooling circuit 2 are switched to the state in step S15, as shown in Figure 3.

[0026] As described above, in the cooling system A according to this embodiment, the motor 12 is located in the first motor flow path 16a, and the inverter 13 is located in the second motor flow path 16b. A switching valve 15 is located at the point where the motor flow path 16 branches into the first motor flow path 16a and the second motor flow path 16b, and the switching valve 15 is configured to switch the motor flow path 16 through which the cooling fluid flows between the first motor flow path 16a and the second motor flow path 16b. As a result, the motor 12 and the inverter 13 are arranged in parallel with respect to the motor flow path 16, and the problem of the amount of heat absorbed by the cooling fluid in the motor 12 decreasing due to the cooling fluid absorbing heat from the inverter 13 before absorbing heat from the motor 12 does not occur. Furthermore, when warming up the battery 22, by circulating the cooling fluid only in the first motor flow path 16a, it is possible to heat the cooling fluid using the self-heating of the motor 12, which has a large heat capacity, and to quickly raise the temperature of the battery 22.

[0027] Furthermore, the switching valve 15 of the cooling system A switches the motor flow path 16 through which the cooling fluid flows between the first motor flow path 16a and the second motor flow path 16b based on whether the temperature of the battery 22 is below the first temperature T1 (e.g., 5 degrees) and whether the temperature of the inverter 13 exceeds the third temperature T3 (e.g., 40 degrees). This allows the cooling fluid to efficiently absorb the heat generated by the motor 12 while appropriately controlling the temperatures of the battery 22 and the inverter 13. In particular, if the inverter 13 has a built-in CPU, it is important to appropriately control the temperature of the inverter 13 because the CPU is sensitive to heat.

[0028] Furthermore, in cooling system A, when the temperature of the battery 22 is below the first temperature T1 (e.g., 5 degrees) and the temperature of the inverter 13 is below the second temperature T2 (e.g., 30 degrees), it is necessary to warm up the battery 22. By switching the switching valve 15 so that the cooling fluid flows only through the first motor passage 16a, the heat from the motor 12, which has a large heat capacity, is efficiently absorbed to heat the cooling water, while the battery 22 is efficiently warmed up. Also, in this state, since the cooling fluid does not flow through the second motor passage 16b, the inverter 13 self-heats without being cooled. Since the inverter 13 may malfunction if it becomes too hot, when the temperature of the inverter 13 exceeds the third temperature T3 (e.g., 40 degrees), the switching valve 15 is switched so that the cooling fluid flows only through the second motor passage 16b. This prevents the inverter 13 from malfunctioning while efficiently warming up the battery 22.

[0029] Furthermore, when the temperature of the battery 22 exceeds the first temperature T1 (for example, 5 degrees), the switching valve 15 of the cooling system A switches the cooling fluid to flow through both the first motor passage 16a and the second motor passage 16b, thus prioritizing the cooling of the motor 12 and inverter 13 over warming up the battery 22.

[0030] [Other embodiments] (1) In the embodiment described above, the switching valve 15 was controlled based on the temperature of the inverter 13, but the switching valve 15 may also be controlled based on the temperature of the motor 12.

[0031] (2) In the above-described embodiment, the chiller 24 was stopped in order to prioritize warming up the battery 22, but the chiller 24 may be operated if it is necessary for the chiller 24 to perform heat exchange by a refrigerant circuit (e.g., a heat pump system) that performs heat exchange in the chiller 24.

[0032] (3) The control of switching between the motor 12 and inverter 13, which are configured in parallel flow paths (first motor flow path 16a and second motor flow path 16b) as in the above-described embodiment, using the switching valve 15 is not limited to the above-described embodiment. For example, when the temperature of the battery 22 is below the first temperature T1 (for example, 5 degrees), the switching valve 15 may be switched so that the cooling fluid flows only through the second motor flow path 16b, and the battery 22 may be warmed up using the self-heating of the inverter 13.

[0033] In the embodiments described above, the following configuration can be envisioned.

[0034] <1> One form of the cooling system (A) comprises a motor (12), a power converter (13), flow paths (16, 16a, 16b) for circulating cooling fluid to the motor (12) and the power converter (13), and a switching valve (15) for switching between the flow paths (16a, 16b) through which the cooling fluid flows. The flow path includes a first flow path (16a) and a second flow path (16b) that branch into two and then rejoin. The motor (12) is located in the first flow path (16a), and the power converter (13) is located in the second flow path (16b). The switching valve (15) is located at the point where the flow path (16) branches into the first flow path (16a) and the second flow path (16b), and is configured to switch between the first flow path (16a) and the second flow path (16b) through which the cooling fluid flows.

[0035] In this embodiment, the motor (12) is located in the first flow path (16a), and the power converter (13) is located in the second flow path (16b). A switching valve (15) is located at the point where the flow path (16) branches into the first flow path (16a) and the second flow path (16b). The switching valve (15) is configured to switch the flow path (16) through which the cooling fluid flows between the first flow path (16a) and the second flow path (16b). As a result, the motor (12) and the power converter (13) are arranged in parallel with respect to the flow paths (16a, 16b), and the problem of the amount of heat absorbed by the cooling fluid in the motor (12) decreasing due to the cooling fluid absorbing heat from the power converter (13) before absorbing heat from the motor (12) does not occur. This makes it possible to provide a cooling system (A) in which the cooling fluid can efficiently absorb the heat generated by the motor (12).

[0036] <2> <1> In the cooling system (A), a battery (22) used to drive a motor (12) is further provided, and the switching valve (15) preferably switches the flow path of the cooling fluid between a first flow path (16a) and a second flow path (16b) based on the temperature of the battery (22).

[0037] According to this, the cooling system (A) further includes a battery (22) used to drive the motor. The switching valve (15) switches the flow path of the cooling fluid between a first flow path (16a) and a second flow path (16b) based on the temperature of the battery (22), so that the temperature of the battery (22) can be appropriately controlled while the cooling fluid can efficiently absorb the heat generated by the motor (12). In addition, when warming up the battery (22), by flowing the cooling fluid only through the first flow path (16a), it is possible to heat the cooling fluid using the self-heating of the motor (12), which has a large heat capacity, and to quickly raise the temperature of the battery (22). <3> <2> In the cooling system (A), it is preferable that a battery channel (26) is provided that can be connected to the channel (16) where the first channel (16a) and the second channel (16b) merge, and that a battery (22) is connected to the battery channel (26).

[0038] According to this, the cooling system (A) is equipped with a battery channel (26) that can be connected to channel (16) where the first channel (16a) and the second channel (16b) merge, and a battery (22) is connected to the battery channel (26). This makes it possible to quickly raise the temperature of the battery (22) by circulating the cooling fluid only through the first channel (16a), using the self-heating of the motor (12) which has a large heat capacity, and then circulating the cooled fluid from channel (16) to the battery channel (26).

[0039] <4> <3> In the cooling system (A) described above, it is preferable that the switching valve (15) switches the flow path of the cooling fluid between a first flow path (16a) and a second flow path (16b) based on the temperature of the power converter (13).

[0040] According to this, the switching valve (15) switches the flow path of the cooling fluid between the first flow path (16a) and the second flow path (16b) based on the temperature of the power converter (13), so that the temperature of the power converter (13) can be appropriately controlled and the cooling fluid can efficiently absorb the heat generated by the motor (12). In particular, if the CPU is built into the power converter (13), the CPU is sensitive to heat, so it is important to appropriately control the temperature of the power converter (13).

[0041] <5> <4> In the cooling system (A) described above, it is preferable that the switching valve (15) is switched so that the cooling fluid flows only through the first channel (16a) when the temperature of the battery (22) is below the first predetermined temperature (T1) and the temperature of the power converter (13) is below the second predetermined temperature (T2), and that the switching valve (15) is switched so that the cooling fluid flows only through the second channel (16b) when the temperature of the battery (22) is below the first predetermined temperature (T1) and the temperature of the power converter (13) exceeds the third predetermined temperature (T3), which is higher than the second predetermined temperature (T2).

[0042] According to this, when the temperature of the battery (22) is below the first predetermined temperature (T1) and the temperature of the power converter (13) is below the second predetermined temperature (T2), it is necessary to warm up the battery (22), so the switching valve (15) is switched so that the cooling fluid flows only through the first passage (16a). This allows the battery (22) to be warmed up efficiently while the cooling fluid is heated by efficiently absorbing the heat from the motor (12). Also, in this state, since the cooling fluid does not flow through the second passage (16b), the power converter (13) generates heat on its own without being cooled. Since the power converter (13) may malfunction if it becomes too hot due to the heat generated, when the temperature of the power converter (13) exceeds the third predetermined temperature (T3), which is higher than the second predetermined temperature (T2), the switching valve (15) is switched so that the cooling fluid flows only through the second passage (16b). This prevents the power converter (13) from malfunctioning while efficiently warming up the battery (22).

[0043] <6> <4> In the cooling system (A) described above, it is preferable that the switching valve (15) is switched so that the cooling fluid flows through both the first flow path (16a) and the second flow path (16b) when the temperature of the battery (22) exceeds a first predetermined temperature (T1).

[0044] According to this, when the temperature of the battery (22) exceeds a first predetermined temperature (T1), the switching valve (15) is switched so that the cooling fluid flows through both the first flow path (16a) and the second flow path (16b), thus prioritizing the cooling of the motor (12) and the power converter (13) over warming up the battery (22). [Industrial applicability]

[0045] This disclosure can be used in cooling systems. [Explanation of symbols]

[0046] 12: Motor, 13: Inverter (power converter), 15: Switching valve, 16: Motor flow path (flow path), 16a: First motor flow path (first flow path, flow path), 16b: Second motor flow path (second flow path, flow path), 22: Battery, 26: Battery flow path (flow path), A: Cooling system, T1: First temperature (first predetermined temperature), T2: Second temperature (second predetermined temperature), T3: Third temperature (third predetermined temperature)

Claims

1. Motor and, Power converter and A motor channel for circulating cooling fluid to the motor and the power converter, A switching valve for switching the motor passage through which the cooling fluid flows, A battery used to drive the motor, The battery comprises a battery channel to which the aforementioned battery is connected, The motor flow path includes a first flow path and a second flow path that branch into two and then rejoin, The motor is arranged in the first flow path, The power converter is located in the second channel, The switching valve is positioned at the point where the motor passage branches into the first passage and the second passage, and is configured to switch the motor passage through which the cooling fluid flows between the first passage and the second passage. The aforementioned battery channel is located downstream of the point where the first channel and the second channel merge again. A cooling system configured to allow switching between a connected state in which the motor flow path and the battery flow path are connected, and an independent state in which the motor flow path and the battery flow path are disconnected.

2. The cooling system according to claim 1, wherein the switching valve switches the motor passage through which the cooling fluid flows between the first passage and the second passage based on the temperature of the battery.

3. The cooling system according to claim 1 or 2, wherein the switching valve switches the motor flow path through which the cooling fluid flows between the first flow path and the second flow path based on the temperature of the power converter.

4. The cooling system according to claim 3, wherein the switching valve is switched so that the cooling fluid flows only through the first channel when the temperature of the battery is below a first predetermined temperature and the temperature of the power converter is below a second predetermined temperature, and when the temperature of the battery is below the first predetermined temperature and the temperature of the power converter exceeds a third predetermined temperature higher than the second predetermined temperature, the cooling fluid flows only through the second channel.

5. The cooling system according to claim 3, wherein the switching valve is switched so that the cooling fluid flows through both the first and second passages when the temperature of the battery exceeds a first predetermined temperature.

6. The cooling system according to claim 1, further comprising a four-way valve disposed between the motor flow path and the battery flow path for switching between the connected state and the independent state.

7. A motor and Power converter and A motor channel for circulating cooling fluid to the motor and the power converter, A switching valve for switching the motor passage through which the cooling fluid flows, The motor comprises a battery used to drive the motor, The motor flow path includes a first flow path and a second flow path that branch into two and then rejoin, The motor is arranged in the first flow path, The power converter is located in the second channel, The switching valve is positioned at the point where the motor passage branches into the first passage and the second passage, and is configured to switch the motor passage through which the cooling fluid flows between the first passage and the second passage. The switching valve is a cooling system that switches the motor flow path through which the cooling fluid flows between the first flow path and the second flow path based on the temperature of the battery.

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