Electric vehicles

Abstract

The present invention provides an electric vehicle that can raise or cool the battery as much as possible by performing control in response to a failure of the switching valve during battery temperature rise control or cooling control. [Solution] The electric vehicle comprises a heating circuit through which a first heat transfer medium is circulated to raise the temperature of a heater core, a battery temperature adjustment circuit through which a second heat transfer medium is circulated to adjust the temperature of the battery, a switching valve that switches the connection state between the heating circuit and the battery temperature adjustment circuit, and a control device that performs heating control or cooling control of the battery. The heating circuit has a first pump and a heater. The battery temperature adjustment circuit has a second pump and a chiller. When the switching valve is open, it connects the heating circuit and the battery temperature adjustment circuit, and when it is closed, it disconnects the heating circuit and the battery temperature adjustment circuit. During the heating control or the cooling control, the control device determines if the switching valve is faulty and performs corresponding control according to the determination result.

Description

Technical Field

[0001] The present invention relates to an electric vehicle.

Background Art

[0002] Patent Document 1 discloses a battery cooling system for cooling a battery pack mounted on an electric vehicle. This battery cooling system includes a refrigerant circuit, a chiller, and a coolant circuit. The refrigerant circuit is a circuit for adjusting the temperature of the coolant circulating in the coolant circuit. The chiller cools the coolant by performing heat exchange between the refrigerant circulating in the refrigerant circuit and the coolant circulating in the coolant circuit. The coolant circuit includes a battery cooling circuit, a pump, and a switching valve. By switching the connection of the path by the switching valve so that the coolant passing through the chiller flows to the battery pack, a battery cooling circuit is formed. When the pump is driven, the coolant flows through the battery pack, and the battery pack is cooled. Hereinafter, the battery pack is referred to as a "battery", and the coolant is referred to as a "heat medium".

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Generally, when the battery becomes excessively hot, it deteriorates, and when it becomes excessively cold, its output performance decreases. An electric vehicle includes a battery temperature adjustment circuit in which a heat medium for adjusting the temperature of the battery circulates in order to maintain the temperature of the battery within a predetermined range. For example, in a high-temperature environment where the temperature of the battery rises, cooling control for cooling the battery is performed by cooling the heat medium of the battery temperature adjustment circuit. In a low-temperature environment where the temperature of the battery drops, heating control for raising the temperature of the battery is performed by heating the heat medium of the battery temperature adjustment circuit.

[0005] Patent Document 1 discloses a control system for detecting abnormalities in a switching valve, but it does not disclose what control is performed when the switching valve fails. In a system that switches the connection of the path so that a heat transfer medium flows through the battery, as disclosed in Patent Document 1, if the switching valve fails, it becomes impossible to regulate the battery temperature. In that case, the battery temperature will immediately fall outside the operating temperature range, and there is a risk that the electric vehicle will become unable to run. An electric vehicle that cannot run cannot drive itself to a safe place or repair shop. To resolve this situation, it is desirable to raise or cool the battery as much as possible so that the electric vehicle can run.

[0006] One of the objectives of the present invention is to provide an electric vehicle that can raise or cool the battery as much as possible by performing control in response to a failure of the switching valve during battery temperature rise control or cooling control. [Means for solving the problem]

[0007] (1) An electric vehicle according to one aspect of the present invention comprises: a heating circuit through which a first heat transfer medium for raising the temperature of a heater core is circulated; a battery temperature adjustment circuit through which a second heat transfer medium for adjusting the temperature of a battery is circulated; a switching valve for switching the connection state between the heating circuit and the battery temperature adjustment circuit; and a control device for performing heating control or cooling control of the battery. The heating circuit includes a first pump for circulating the first heat transfer medium and a heater for heating the first heat transfer medium. The battery temperature adjustment circuit includes a second pump for circulating the second heat transfer medium and a chiller for cooling the second heat transfer medium. The switching valve is configured to connect the heating circuit and the battery temperature adjustment circuit when open, and to disconnect the heating circuit and the battery temperature adjustment circuit when closed. The control device determines if the switching valve is faulty during heating control or cooling control, and performs corresponding control according to the determination result. The heating control opens the switching valve, turns on the heater, and drives at least one of the first pump and the second pump. The cooling control involves closing the switching valve, turning on the chiller, and driving the second pump. The fault is detected based on the change in temperature of the second heat transfer medium upstream of the battery.

[0008] (2) In the electric vehicle described in (1) above, if it is determined that the switching valve is fixed in the fully closed position during the temperature rise control, control may be performed to stop the second pump. [Effects of the Invention]

[0009] The electric vehicle described in (1) above can perform battery heating or cooling as much as possible, even if the switching valve fails, by performing corresponding control during heating or cooling control in response to a switching valve failure. Therefore, it is possible to drive the electric vehicle to a safe location or repair shop.

[0010] The electric vehicle described in (2) above can raise the temperature of the battery as much as possible by promoting the rise in temperature due to the battery's own heat generation. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a functional block diagram of an electric vehicle according to an embodiment. [Figure 2] Figure 2 is a functional block diagram showing the configuration of the heating circuit and battery temperature control circuit provided in the electric vehicle according to this embodiment. [Figure 3] Figure 3 is a flowchart showing an example of fault detection and response control in temperature rise control by an electric vehicle according to this embodiment. [Figure 4] Figure 4 is a flowchart showing an example of fault detection and response control in cooling control by an electric vehicle according to this embodiment. [Modes for carrying out the invention]

[0012] Specific examples of electric vehicles according to embodiments of the present invention will be described with reference to the drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. The shapes, dimensions, and dimensional ratios of the components shown in each figure are represented for the purpose of clarifying the explanation and do not necessarily represent the actual shapes, dimensions, and dimensional ratios. The present invention is not limited to the following examples, but is as shown in the claims, and includes all modifications within the meaning and scope equivalent to the claims.

[0013] <Electric Vehicles> Referring to Figure 1, the configuration of the electric vehicle 1 according to this embodiment will be described. The electric vehicle 1 is an automobile that drives a motor (not shown) using the power of a battery 10. The electric vehicle 1 in this example is a BEV (Battery Electric Vehicle). The electric vehicle 1 may also be, for example, a HEV (Hybrid Electric Vehicle).

[0014] As shown in Figure 1, the electric vehicle 1 comprises a heating circuit 3, a battery temperature control circuit 6, a switching valve 7, and a control device 5. The heating circuit 3 circulates a first heat transfer medium to raise the temperature of the heater core 26 of the air conditioning unit 2. The battery temperature control circuit 6 circulates a second heat transfer medium to regulate the temperature of the battery 10. The heating circuit 3 and the battery temperature control circuit 6 are connected by a switching valve 7 that connects or disconnects the heating circuit 3 and the battery temperature control circuit 6. The electric vehicle 1 in this example further comprises a heat pump circuit 4. The heat pump circuit 4 is a device for adjusting the temperature of the first heat transfer medium circulating in the heating circuit 3 and the second heat transfer medium circulating in the battery temperature control circuit 6. The heat pump circuit 4 circulates a third heat transfer medium. In Figure 1, the white arrows indicate the flow direction of the first heat transfer medium, the second heat transfer medium, and the third heat transfer medium, respectively. The configuration of the electric vehicle 1 will be described in detail below.

[0015] ≪Battery≫ The battery 10 is used as a power source to drive the motor for traction. In addition to supplying power to the motor, the battery 10 also supplies power to various electrical devices mounted on the electric vehicle 1. The battery 10 generates heat during charging and discharging. The battery 10 has a flow path through which the second heat transfer medium of the battery temperature control circuit 6 flows. The temperature of the battery 10 is controlled by the second heat transfer medium. The battery 10 in this example is equipped with a battery temperature sensor 10t that detects the temperature of the battery 10.

[0016] Air conditioning unit The air conditioning unit 2 is a device that provides air conditioning for the vehicle interior. The air conditioning unit 2 is also called HVAC (Heating, Ventilation and Air Conditioning). The air conditioning unit 2 adjusts the temperature of the air taken in from the inlet 2i and sends the temperature-adjusted air into the vehicle interior from the outlet 2o.

[0017] The air conditioning unit 2 has a heater core 26, an evaporator 27, an air mix door 28, and a blower 29. The evaporator 27, the air mix door 28, and the heater core 26 are arranged in order from the inlet 2i toward the outlet 2o in the air conditioning unit 2. The blower 29 sucks air from the inlet 2i and flows the sucked air toward the outlet 2o.

[0018] The evaporator 27 is a component that cools air. A third heat medium is supplied to the evaporator 27 from a heat pump circuit 4 described later. The third heat medium supplied to the evaporator 27 expands by a cooling expansion valve 46 and becomes low temperature and low pressure. The cooling expansion valve 46 is, for example, an electric expansion valve. By supplying a low-temperature third heat medium to the evaporator 27, the evaporator 27 becomes low temperature, and the air passing around the evaporator 27 is cooled.

[0019] The heater core 26 is a component that warms air. The heater core 26 is arranged downstream of the evaporator 27. The first heat medium of the heating circuit 3 is supplied to the heater core 26. By supplying a high-temperature first heat medium to the heater core 26, the heater core 26 becomes high temperature, and the air passing around the heater core 26 is warmed.

[0020] The air mix door 28 is a component that adjusts the ratio of the air passing through the heater core 26 and the air bypassing the heater core 26. The air mix door 28 is arranged between the evaporator 27 and the heater core 26. The air cooled by the evaporator 27 and the air warmed by the heater core 26 are mixed by the air mix door 28, and the temperature of the air blown out from the outlet 2o is adjusted.

[0021] ≪Heating Circuit≫ The heating circuit 3 is used to raise the temperature of the heater core 26 when the heating of the air conditioner is ON. The heating circuit 3 is also used to warm the second heat transfer medium of the battery temperature control circuit 6, which will be described later, in order to raise the temperature of the battery 10. As shown in Figure 2, the heating circuit 3 has a first pump 31 that circulates the first heat transfer medium and a heater 32 that heats the first heat transfer medium. The first heat transfer medium is, for example, long-life coolant (LLC). The first pump 31 is an electric water pump. The heater 32 is an electric heater such as a high-voltage heater (HVH). The heater 32 is located between the heat exchanger 34, which will be described later, and the heater core 26. The output of the heater 32 in this example is adjustable. By adjusting the output of the heater 32, the temperature of the first heat transfer medium supplied to the heater core 26 can be adjusted.

[0022] In this example, the heating circuit 3 is configured such that the first heat transfer medium, sent from the first pump 31, circulates sequentially through the heat exchanger 34, heater 32, and heater core 26. The heater core 26 is heated by heating the first heat transfer medium in either or both of the heater 32 and the heat pump circuit 4 described later. When the heating of the air conditioner is OFF, the first pump 31 is basically stopped, and the heated first heat transfer medium is not supplied to the heater core 26.

[0023] The heating circuit 3 is equipped with a first temperature sensor 35a and a second temperature sensor 35b. The first temperature sensor 35a detects the temperature of the first heat transfer medium upstream of the heater core 26. The first temperature sensor 35a is located between the heater 32 and the heater core 26. The second temperature sensor 35b detects the temperature of the first heat transfer medium downstream of the heater core 26. The second temperature sensor 35b is located near the outlet of the heater core 26 where the first heat transfer medium that has passed through the heater core 26 is discharged.

[0024] A reserve tank 33 may be provided in the heating circuit 3. The reserve tank 33 is a tank that temporarily stores the first heat transfer medium that overflows from the heating circuit 3 due to thermal expansion caused by the temperature rise of the first heat transfer medium. The reserve tank 33 also has the function of separating bubbles generated in the heating circuit 3. By separating the first heat transfer medium and bubbles in the heating circuit 3 with the reserve tank 33 and removing the bubbles in the heating circuit 3, the pressure in the heating circuit 3 can be kept stable.

[0025] The heating circuit 3 in this example includes a heat exchanger 34 that performs heat exchange between a third heat transfer medium and a first heat transfer medium flowing through a heat pump circuit 4, which will be described later. The heat exchanger 34 has a first heat exchange section 34a through which the first heat transfer medium flows, and a second heat exchange section 34b through which the third heat transfer medium flows. The first heat exchange section 34a and the second heat exchange section 34b are thermally connected to each other, thereby performing heat exchange between the first heat transfer medium and the third heat transfer medium. The heat exchanger 34 is, for example, a water-cooled condenser.

[0026] In this example, the heating circuit 3 is connected to the heat pump circuit 4 by a heat exchanger 34, and the first heat transfer medium of the heating circuit 3 can be heated by the heat pump circuit 4. Therefore, in this example, the heating circuit 3 can heat the first heat transfer medium by the heat pump circuit 4 even when the heater 32 is OFF. In this example, the heating circuit 3 can also heat the first heat transfer medium by both the heat pump circuit 4 and the heater 32. For example, if the first heat transfer medium cannot be sufficiently heated by the heat pump circuit 4 alone, the first heat transfer medium can be heated by both the heat pump circuit 4 and the heater 32.

[0027] ≪Heat pump circuit≫ The heat pump circuit 4 is used to heat the first heat transfer medium of the heating circuit 3. The heat pump circuit 4 is also used to cool the evaporator 27. Furthermore, the heat pump circuit 4 is also used to cool the second heat transfer medium of the battery temperature control circuit 6 (described later) in order to cool the battery 10. The heat pump circuit 4 in this example has a configuration similar to that of a typical heat pump device. The heat pump circuit 4 includes a compressor 41, a condenser 42, a heating expansion valve 44, and a cooling expansion valve 46.

[0028] In this example, the heat pump circuit 4 is configured such that the third heat transfer medium discharged from the compressor 41 is sent to the condenser 42 via the heat exchanger 34 and heating expansion valve 44 of the heating circuit 3. The third heat transfer medium has the property of becoming hot when compressed and becoming cold when expanded. The third heat transfer medium is, for example, hydrofluorocarbon (HFC).

[0029] The compressor 41 compresses and discharges the low-pressure third heat transfer medium sent from the accumulator 45. The third heat transfer medium, compressed to high temperature and pressure by the compressor 41, is sent to the heat exchanger 34. The compressor 41 is an electric compressor. The heat exchanger 34 performs heat exchange between the high-temperature third heat transfer medium sent from the compressor 41 and the first heat transfer medium of the heating circuit 3. As the high-temperature third heat transfer medium flows through the second heat exchange section 34b, the first heat transfer medium in the first heat exchange section 34a is heated. As the first heat transfer medium circulating in the heating circuit 3 is heated, the heater core 26 is heated. The third heat transfer medium that has passed through the heat exchanger 34 is sent to the condenser 42 through the heating expansion valve 44. The third heat transfer medium expands in the heating expansion valve 44 and becomes low temperature and low pressure.

[0030] The condenser 42 is a device that performs heat exchange between the third heat transfer medium passing through the condenser 42 and the outside air. The outside air is taken in from the front grille 11. The fan 12 blows air onto the condenser 42. The airflow from the fan 12 hits the condenser 42, causing heat exchange between the third heat transfer medium inside the condenser 42 and the outside air. The fan 12 is located behind the condenser 42.

[0031] The heat pump circuit 4 in this example has a first flow path 4a, a second flow path 4b, and a third flow path 4c. The first flow path 4a is a flow path that sends the third heat transfer medium from the capacitor 42 to the evaporator 27. The first flow path 4a is used when cooling the evaporator 27. The second flow path 4b is a flow path that sends the third heat transfer medium from the capacitor 42 to the chiller 62 of the battery temperature control circuit 6, which will be described later. The second flow path 4b is used when cooling the battery 10. The third flow path 4c is a bypass flow path that returns the third heat transfer medium from the capacitor 42 to the compressor 41. The third flow path 4c is used when the evaporator 27 is not being cooled and when the battery 10 is not being cooled. The flow path is switched by a flow path switching valve 40. The flow path switching valve 40 is a solenoid valve. When the flow path switching valve 40 is closed, the third heat transfer medium discharged from the capacitor 42 flows towards the first flow path 4a and the second flow path 4b. When the flow path switching valve 40 is open, the third heat transfer medium flows through the third flow path 4c.

[0032] When cooling the evaporator 27 or the battery 10, the flow path switching valve 40 is closed. When cooling the evaporator 27, the third heat transfer medium flows through the first flow path 4a. After being sent to the evaporator 27 through the first flow path 4a, the third heat transfer medium is returned to the compressor 41. The third heat transfer medium expands in the cooling expansion valve 46 before reaching the evaporator 27 and is supplied to the evaporator 27 in a low temperature and low pressure state. When the evaporator 27 is not being cooled, the cooling expansion valve 46 is closed, and the third heat transfer medium does not flow through the first flow path 4a. In other words, the third heat transfer medium is not supplied to the evaporator 27.

[0033] When cooling the battery 10, the third heat transfer medium flows through the second flow path 4b. The third heat transfer medium is sent to the chiller 62 via the second flow path 4b and then returned to the compressor 41. The third heat transfer medium expands in the chiller expansion valve 49 before reaching the chiller 62 and is supplied to the chiller 62 in a low-temperature, low-pressure state. The chiller 62 will be described later. When the battery 10 is not being cooled, the chiller expansion valve 49 is closed, and the third heat transfer medium does not flow through the second flow path 4b. In other words, the third heat transfer medium is not supplied to the chiller 62.

[0034] If the evaporator 27 is not cooled and the battery 10 is not cooled, the flow path switching valve 40 is open, and the third heat transfer medium is returned to the compressor 41 through the third flow path 4c. In this case, the third heat transfer medium does not flow through the first flow path 4a and the second flow path 4b.

[0035] The third heat transfer medium, which is returned to the compressor 41 through one of the first flow path 4a, the second flow path 4b, or the third flow path 4c, is collected in the accumulator 45. The accumulator 45 separates the liquefied third heat transfer medium and supplies only the vaporized third heat transfer medium to the compressor 41.

[0036] ≪Battery temperature adjustment circuit≫ The battery temperature control circuit 6 is a circuit that adjusts the temperature of the battery 10 using a second heat transfer medium. The temperature of the battery 10 is adjusted as the second heat transfer medium circulates through the battery temperature control circuit 6. The second heat transfer medium is, for example, LLC (Long Life Coolant). The second heat transfer medium and the first heat transfer medium of the heating circuit 3 are the same.

[0037] As shown in Figure 2, the battery temperature control circuit 6 includes a second pump 61 for circulating the second heat transfer medium and a chiller 62 for cooling the second heat transfer medium. The battery 10 is cooled by the chiller 62 cooling the second heat transfer medium. The second pump 61 is an electric water pump. In this example, the battery temperature control circuit 6 is configured so that the second heat transfer medium sent from the second pump 61 circulates through the battery 10 and the chiller 62. As will be described later, in this example, the battery 10 is cooled by the chiller 62 cooling the second heat transfer medium. The battery 10 is heated by sending the heated first heat transfer medium from the heating circuit 3 to the battery temperature control circuit 6 through the switching valve 7. In other words, in the battery temperature control circuit 6, the chiller 62 functions as a device for cooling the second heat transfer medium. The heating circuit 3 and the switching valve 7 function as devices for heating the second heat transfer medium.

[0038] In this example, the battery temperature control circuit 6 cools the battery 10 by cooling the second heat transfer medium with a chiller 62. The chiller 62 in this example is located downstream of the battery 10 and cools the second heat transfer medium after it has passed through the battery 10. The chiller 62 is a heat exchanger that cools the second heat transfer medium using the third heat transfer medium of the heat pump circuit 4. The chiller 62 has a first heat exchange section 62a through which the second heat transfer medium flows and a second heat exchange section 62b through which the third heat transfer medium flows. The first heat exchange section 62a and the second heat exchange section 62b are thermally connected to each other, so that heat exchange takes place between the second heat transfer medium and the third heat transfer medium. The low-temperature third heat transfer medium, expanded by the chiller expansion valve 49 described above, flows through the second heat exchange section 62b, cooling the second heat transfer medium in the first heat exchange section 62a. The battery 10 is cooled as the second heat transfer medium circulating in the battery temperature control circuit 6 is cooled.

[0039] The heat pump circuit 4 in this example is equipped with a first temperature sensor 47a and a second temperature sensor 47b. The first temperature sensor 47a detects the temperature of the third heat transfer medium before it passes through the chiller 62. The first temperature sensor 47a is located near the inlet of the second heat exchange section 62b into which the third heat transfer medium flows. The second temperature sensor 47b detects the temperature of the third heat transfer medium after it has passed through the chiller 62. The second temperature sensor 47b is located near the outlet of the second heat exchange section 62b into which the third heat transfer medium is discharged.

[0040] The battery temperature control circuit 6 is equipped with a temperature sensor 65. The temperature sensor 65 detects the temperature of the second heat transfer medium upstream of the battery 10. The temperature sensor 65 is located near the inlet of the battery 10 into which the second heat transfer medium flows.

[0041] In this example, the battery temperature control circuit 6 is configured to suppress the increase in pressure due to the thermal expansion of the second heat transfer medium. When the pressure of the second heat transfer medium exceeds a predetermined level, a portion of the second heat transfer medium is sent to the reserve tank 33.

[0042] The battery temperature control circuit 6 in this example does not include a battery heater that heats a second heat transfer medium to raise the temperature of the battery 10.

[0043] ≪Switching valve≫ The switching valve 7 is a component that switches the connection state between the heating circuit 3 and the battery temperature control circuit 6. In this example, the heating circuit 3 and the battery temperature control circuit 6 are connected by the switching valve 7 so that the heat transfer medium can move between the heating circuit 3 and the battery temperature control circuit 6. The switching valve 7 allows or blocks the movement of the heat transfer medium. The switching valve 7 is a solenoid valve.

[0044] The switching valve 7 in this example is a four-way valve that can branch the flow path in four directions. A known four-way valve (for example, Japanese Patent Publication No. 2013-238310, Japanese Patent Publication No. 2020-200902) can be used. The switching valve 7 is not limited to a four-way valve, but can be any valve that can branch the flow path in four or more directions.

[0045] In this example, the switching valve 7 is positioned between the heating circuit 3 and the battery temperature control circuit 6 and has four connection ports. The switching valve 7 connects a point in the heating circuit 3 to a point in the battery temperature control circuit 6. In the heating circuit 3, the connection point of the switching valve 7 is located in the middle of the flow path from the heater core 26 to the first pump 31, more specifically in the flow path between the second temperature sensor 35b and the reserve tank 33. Of the four connection ports of the switching valve 7, the first and second connection ports are connected to points A and B in the heating circuit 3, respectively. In the battery temperature control circuit 6, the connection point of the switching valve 7 is located in the middle of the flow path from the chiller 62 to the second pump 61. Of the four connection ports of the switching valve 7, the third and fourth connection ports are connected to points C and D in the battery temperature control circuit 6, respectively.

[0046] When the switching valve 7 is closed, it shuts off the connection between the heating circuit 3 and the battery temperature control circuit 6. When the switching valve 7 is closed, the connection between the heating circuit 3 and the battery temperature control circuit 6 is cut off, so the heating circuit 3 and the battery temperature control circuit 6 become independent parallel circuits. In other words, when the switching valve 7 is closed, the movement of the heat transfer medium between the heating circuit 3 and the battery temperature control circuit 6 is impossible. When the switching valve 7 is closed, all of the first heat transfer medium that entered the switching valve 7 from point A in the heating circuit 3 flows from the switching valve 7 to point B in the heating circuit 3. Therefore, the first heat transfer medium circulates in the heating circuit 3 without being sent to the battery temperature control circuit 6 through the switching valve 7. Also, when the switching valve 7 is closed, all of the second heat transfer medium that entered the switching valve 7 from point C in the battery temperature control circuit 6 flows from the switching valve 7 to point D in the battery temperature control circuit 6. Therefore, the second heat transfer medium circulates in the battery temperature control circuit 6 without being sent to the heating circuit 3 through the switching valve 7.

[0047] When the switching valve 7 is open, it connects the heating circuit 3 and the battery temperature control circuit 6. When the switching valve 7 is open, the heating circuit 3 and the battery temperature control circuit 6 are in communication, forming a series circuit. In other words, when the switching valve 7 is open, the heat transfer medium can move between the heating circuit 3 and the battery temperature control circuit 6. When the switching valve 7 is open, the first heat transfer medium that enters the switching valve 7 from point A in the heating circuit 3 flows from the switching valve 7 to point D in the battery temperature control circuit 6. Therefore, the first heat transfer medium is sent to the battery temperature control circuit 6 through the switching valve 7 and returns to the heating circuit 3 via the battery temperature control circuit 6. Also, when the switching valve 7 is open, the second heat transfer medium that enters the switching valve 7 from point C in the battery temperature control circuit 6 flows from the switching valve 7 to point B in the heating circuit 3. Therefore, the second heat transfer medium is sent to the heating circuit 3 through the switching valve 7 and returns to the battery temperature control circuit 6 via the heating circuit 3. Therefore, when the switching valve 7 is open, the first heat transfer medium of the heating circuit 3 and the second heat transfer medium of the battery temperature control circuit 6 are mixed.

[0048] The opening degree of the switching valve 7 in this example is adjustable. By adjusting the opening degree of the switching valve 7, the amount of heat transfer medium between the heating circuit 3 and the battery temperature control circuit 6 can be adjusted. The detailed configuration of the switching valve 7 is not shown here, but the switching valve 7 has, for example, a valve body and a valve shaft that rotatably supports the valve body. The valve body rotates integrally with the valve shaft. The opening degree of the switching valve 7 is adjusted by adjusting the rotation angle of the valve shaft.

[0049] In this example, the battery temperature control circuit 6 raises the temperature of the battery 10 by sending the first heat transfer medium from the heating circuit 3 to the battery temperature control circuit 6 via the switching valve 7. When raising the temperature of the battery 10, the first heat transfer medium is heated by the heater 32. The heating of the first heat transfer medium may be done by using both the heater 32 and the heat pump circuit 4. The temperature of the first heat transfer medium heated by the heating circuit 3 is higher than the temperature of the battery 10.

[0050] When the battery 10 is heated, the switching valve 7 is switched to the open state. When the switching valve 7 is open, the first heat transfer medium heated in the heating circuit 3 is sent to the battery temperature control circuit 6. In other words, the second heat transfer medium in the battery temperature control circuit 6 can be heated using the heater 32, or by using the heater 32 and the heat pump circuit 4 in combination. The second heat transfer medium is heated when the first and second heat transfer mediums are mixed. As the second heat transfer medium circulating in the battery temperature control circuit 6 is heated, the battery 10 is heated.

[0051] When raising the temperature of the battery 10, it is sufficient for at least one of the pumps, the first pump 31 of the heating circuit 3 and the second pump 61 of the battery temperature control circuit 6, to be driven. When the switching valve 7 is open, as described above, the heating circuit 3 and the battery temperature control circuit 6 are in a series circuit, so if at least one of the pumps is driven, the first heat transfer medium flows through the heating circuit 3 and the second heat transfer medium flows through the battery temperature control circuit 6.

[0052] When the battery 10 is not heated, the switching valve 7 switches to the closed position. When the switching valve 7 is closed, the first heat transfer medium of the heating circuit 3 is not sent to the battery temperature control circuit 6, and therefore the second heat transfer medium of the battery temperature control circuit 6 is not heated by the first heat transfer medium. Also, when the battery 10 is not heated, the second pump 61 is stopped.

[0053] When cooling the battery 10, the switching valve 7 is switched to the closed state. When cooling the battery 10, the second pump 61 is driven and the second heat transfer medium is cooled by the chiller 62. The second heat transfer medium cooled by the chiller 62 circulates through the battery temperature control circuit 6, thereby cooling the battery 10. The temperature of the second heat transfer medium cooled by the chiller 62 is lower than the temperature of the battery 10. On the other hand, when the battery 10 is not being cooled, the second pump 61 is stopped and the second heat transfer medium does not circulate. Also, when the battery 10 is not being cooled, as described above, the third heat transfer medium from the heat pump circuit 4 is not supplied to the chiller 62, so the second heat transfer medium is not cooled. In other words, the chiller 62 is turned OFF.

[0054] ≪Control device≫ The control device 5 controls the temperature of the battery 10 so that its temperature is maintained within a predetermined range. In this example, the control device 5 controls the air conditioning unit 2, the heating circuit 3, the battery temperature control circuit 6, the heat pump circuit 4, and the switching valve 7. In addition to controlling the temperature of the battery 10, the control device 5 in this example also performs controls for air conditioning. The controls for adjusting the temperature of the battery 10 include cooling control to cool the battery 10 and heating control to raise the temperature of the battery 10. The controls for air conditioning include raising the temperature of the heater core 26 and cooling the evaporator 27.

[0055] The control device 5 is comprised of, for example, an ECU. Each process performed by the control device 5 is realized by a processing circuit (Circuitry) that includes one or more processors.

[0056] The above processing circuit may consist of one or more processors, one or more memories, various analog circuits, various digital circuits, etc., combined in an integrated circuit, and may also include an input / output interface (I / F). The one or more memories store programs (instructions) that cause the one or more processors to execute each of the above processes. The one or more memories are typically ROM (Read-Only Memory) and RAM (Random Access Memory).

[0057] One or more of the above processors may execute each of the above processes according to the above program read from one or more of the above memory, or they may execute each of the above processes according to logic circuits that have been pre-designed to execute each of the above processes. The above processors may be various processors suitable for computer control, such as CPUs (Central Processing Units), GPUs (Graphics Processing Units), DSPs (Digital Signal Processors), FPGAs (Field Programmable Gate Arrays), and ASICs (Application Specific Integrated Circuits). Furthermore, multiple physically separated processors may cooperate with each other to execute each of the above processes.

[0058] [Temperature control] The control device 5 starts temperature control when the temperature of the battery 10 falls below the temperature start temperature and ends the temperature control when the temperature of the battery 10 rises to or above the temperature end temperature. In this example, the temperature control of the battery 10 is performed as follows: The switching valve 7 is opened. When the switching valve 7 is open, the opening degree of the switching valve 7 is at the fully open position. The heater 32 is turned ON to heat the first heat transfer medium of the heating circuit 3. At this time, the heat pump circuit 4 may also be operated to heat the first heat transfer medium. In addition, at least one of the first pump 31 of the heating circuit 3 and the second pump 61 of the battery temperature adjustment circuit 6 is driven. As a result, the heated first heat transfer medium is sent from the heating circuit 3 to the battery temperature adjustment circuit 6, warming the second heat transfer medium of the battery temperature adjustment circuit 6. The heated second heat transfer medium circulates through the battery temperature adjustment circuit 6, causing the battery 10 to rise in temperature. The temperature control is performed until the temperature of the battery 10 rises to or above the temperature end temperature. The temperature start temperature is the set temperature when the temperature control is started. The heating end temperature is the set temperature at which the heating control is terminated. The heating start temperature is set, for example, to a temperature lower than the heating end temperature. When terminating the heating control, the switching valve 7 is switched from the open state to the closed state. At the same time, heating of the first heat transfer medium by the heater 32 is stopped, and the second pump 61 is stopped.

[0059] [Cooling control] The control device 5 starts cooling control when the temperature of the battery 10 exceeds the cooling start temperature and ends the cooling control when the temperature of the battery 10 falls below the cooling end temperature. In this example, the cooling control is performed as follows: The switching valve 7 is closed. When the switching valve 7 is closed, the opening of the switching valve 7 is in the fully closed position. The heat pump circuit 4 is activated to turn on the chiller 62, thereby cooling the second heat transfer medium in the battery temperature adjustment circuit 6. The second pump 61 is also driven. As a result, the cooled second heat transfer medium circulates through the battery temperature adjustment circuit 6, cooling the battery 10. The cooling control is performed until the temperature of the battery 10 falls below the cooling end temperature and ends when the temperature of the battery 10 falls below the cooling end temperature. The cooling start temperature is the set temperature when the cooling control is started. The cooling end temperature is the set temperature when the cooling control is ended. The cooling start temperature is set to a temperature higher than the cooling end temperature, for example. When ending the cooling control, the cooling of the second heat transfer medium by the chiller 62 is stopped and the second pump 61 is stopped.

[0060] If the switching valve 7 malfunctions, it becomes impossible to control the opening and closing of the switching valve 7, making it impossible to perform normal temperature rise control or cooling control. The control device 5 determines if the switching valve 7 has malfunctioned during temperature rise control or cooling control and performs corresponding control according to the determination result. "During temperature rise control or cooling control" refers to the series of processes from deciding to start each control until it ends. "From deciding to start each control" also includes "immediately before starting the control".

[0061] [Fault detection of switching valve] The failure detection of the switching valve 7 includes not only determining whether the switching valve 7 is faulty, but also determining the type of fault. The fault types of the switching valve 7 include a fault where the opening degree of the switching valve 7 becomes unstable, and a fault where the opening degree of the switching valve 7 becomes fixed. Failures of the switching valve 7 include not only physical failures of the switching valve 7, but also malfunctions in the software that controls the switching valve 7.

[0062] If the control device 5 determines that there is a malfunction, it may notify the occupants that the switching valve 7 is malfunctioning. This notification may be made, for example, by at least one of a visual announcement and an auditory announcement. A visual announcement may be, for example, a display on the center display or the illumination of a lamp located near the tachometer and speedometer on the instrument panel. An auditory announcement may be, for example, an alarm sound or an automated voice notification.

[0063] <Types of malfunctions> A failure condition in which the opening degree of the switching valve 7 becomes unstable is a failure in which the opening degree of the switching valve 7 is not fixed and the opening degree fluctuates repeatedly. This failure condition is called the "first failure condition". The first failure condition can be caused by hardware factors such as the breakage of the valve shaft that supports the valve body, or by software factors such as a malfunction in the control signal. In the case of the first failure condition, the switching valve 7 is not kept open or closed and the opening degree fluctuates, so the amount of heat transfer medium moving between the heating circuit 3 and the battery temperature control circuit 6 fluctuates. In other words, the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 fluctuates.

[0064] A fault condition in which the opening degree of the switching valve 7 is fixed means that the switching valve 7 does not operate. This fault condition can be caused by hardware factors such as the valve body becoming stuck due to the adhesion of foreign matter, or by software factors such as a malfunction in the control signal. This fault condition has two states: one in which the switching valve 7 is fixed in the fully open or fully closed position, and another in which it is fixed in an intermediate position. The state in which the switching valve 7 is fixed in the fully open or fully closed position is called the "second fault condition." The state in which the switching valve 7 is fixed in an intermediate position is called the "third fault condition." In the second fault condition, where the switching valve 7 is fixed in the fully closed position, the switching valve 7 does not open, and the first heat transfer medium is not sent from the heating circuit 3 to the battery temperature control circuit 6. In the second fault condition, where the switching valve 7 is fixed in the fully open position, the switching valve 7 does not close, and the first heat transfer medium is sent from the heating circuit 3 to the battery temperature control circuit 6. In the third fault condition, where the switching valve 7 is fixed at an intermediate opening, the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 is reduced compared to when the switching valve 7 is fully open.

[0065] The failure detection of the switching valve 7 is performed based on the temperature change of the second heat transfer medium upstream of the battery 10. The corresponding control is performed according to the result of the failure detection of the switching valve 7. The corresponding control is a control that differs from normal heating control or cooling control, and is a control that heats or cools the battery. The corresponding control is a control that attempts to maintain the battery temperature within an appropriate temperature range even if the switching valve 7 is faulty. This control changes at least one of the temperature and flow rate of the second heat transfer medium. In heating control, the corresponding control performs at least one of heating the second heat transfer medium and adjusting the flow rate of the second heat transfer medium compared to normal heating control. Heating the second heat transfer medium is performed by increasing the output of the heater 32 at least compared to normal heating control. Heat pump circuit 4 may be used in combination with heating the second heat transfer medium as needed. Adjusting the flow rate of the second heat transfer medium includes increasing the flow rate of the second heat transfer medium as well as stopping the flow of the second heat transfer medium. In cooling control, the corresponding control performs at least one of cooling the second heat transfer medium and adjusting the flow rate of the second heat transfer medium compared to normal cooling control. The cooling of the second heat transfer medium is performed by increasing the output of the chiller 62 compared to the normal cooling control. The fault detection and response control in the temperature rise control will be explained in detail below.

[0066] <Fault detection in temperature rise control> 《Determination of whether or not there is a malfunction》 In temperature rise control, a fault is determined if the temperature difference ΔTα between the first temperature T2u of the second heat transfer medium upstream of the battery 10 and the second temperature T1d of the first heat transfer medium downstream of the heater core 26 is greater than a predetermined temperature difference ΔTx. In temperature rise control, as described above, opening the switching valve 7 creates a series circuit between the heating circuit 3 and the battery temperature adjustment circuit 6. If the switching valve 7 is not faulty and is in the open state, the heated first heat transfer medium is sent from the heating circuit 3 to the battery temperature adjustment circuit 6, thereby heating the second heat transfer medium. In this example, the first heat transfer medium discharged from the outlet of the heater core 26 flows from point A of the heating circuit 3 through the switching valve 7 to point D of the battery temperature adjustment circuit 6 and is sent to the battery 10. If the switching valve 7 is in the open state, the second temperature T1d of the first heat transfer medium and the first temperature T2u of the second heat transfer medium will be approximately the same. Therefore, if the temperature difference ΔTα is less than or equal to the predetermined temperature difference ΔTx, a fault is determined not to exist. In the case of temperature rise control, even if the switching valve 7 is stuck in the fully open position due to a malfunction, normal temperature rise control can be continued, so it is determined that there is no malfunction. Even if the malfunction of the switching valve 7 being stuck in the fully open position cannot be detected, the malfunction of the switching valve 7 being stuck in the fully open position can be detected when cooling control is performed next.

[0067] In the first fault state, where the opening of the switching valve 7 is unstable, the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 fluctuates, and the second heat transfer medium is not sufficiently heated. In the second fault state, where the switching valve 7 is fixed in the fully closed position, the first heat transfer medium is not sent from the heating circuit 3 to the battery temperature control circuit 6, and therefore the second heat transfer medium is not heated. In the third fault state, where the switching valve 7 is fixed at an intermediate opening, a portion of the first heat transfer medium is sent from the heating circuit 3 to the battery temperature control circuit 6. Because the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 decreases, the second heat transfer medium is not sufficiently heated. In any of these fault states, the temperature difference ΔTα becomes large. Therefore, if the temperature difference ΔTα is greater than a predetermined temperature difference ΔTx, a fault is determined to exist.

[0068] The temperature difference ΔTα is an absolute value. A given temperature difference ΔTx is, for example, 10°C. A given temperature difference ΔTx may also be 5°C.

[0069] The first temperature T2u of the second heat transfer medium is obtained by the temperature sensor 65. The second temperature T1d of the first heat transfer medium is obtained by the second temperature sensor 35b.

[0070] Determining the state of malfunction In temperature rise control, if the judgment result indicates a fault, the fault state is determined based on the variation σT of the change in the first temperature T2u. If the variation σT of the change in the first temperature T2u is greater than or equal to a predetermined threshold Ty, it is determined to be a first fault state. If the variation σT of the change in the first temperature T2u is less than the predetermined threshold Ty, and the amount of change ΔTf of the first temperature T2u is less than or equal to a predetermined amount of change ΔTz, it is determined to be a second fault state in which the switching valve 7 is fixed in the fully closed position. If the variation σT of the change in the first temperature T2u is less than the predetermined threshold Ty, and the amount of change ΔTf of the first temperature T2u is greater than the predetermined amount of change ΔTz, it is determined to be a third fault state.

[0071] 《Determination of the first malfunction state》 In the first fault condition, the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 fluctuates, causing the first temperature T2u to fluctuate. Since the variability σT of the change in the first temperature T2u becomes large, if the variability σT of the change in the first temperature T2u is greater than or equal to a predetermined threshold Ty, it can be determined that the system is in a first fault condition. The variability σT of the change in the first temperature T2u is obtained, for example, by calculating the standard deviation of the first temperature T2u per unit time. The unit time is, for example, 10 seconds or more and 60 seconds or less. The unit time may be 30 seconds or more. The number of data points for the first temperature T2u per unit time is, for example, 30 or more and 120 or less. The number of data points for the first temperature T2u may be 60 or more. For example, if the sampling period for acquiring the first temperature T2u is 1 second, the number of data points per unit time of 60 seconds is 60. The predetermined threshold Ty is, for example, 10°C. The predetermined threshold Ty may be 5°C.

[0072] Determination of the second failure state In the second fault state, where the switching valve 7 is fixed in the fully closed position, the heated first heat transfer medium is not sent from the heating circuit 3 to the battery temperature control circuit 6, so the first temperature T2u does not fluctuate substantially and does not rise. Therefore, the variation σT of the change in the first temperature T2u is small, and the amount of change ΔTf of the first temperature T2u is small. For this reason, if the variation σT of the change in the first temperature T2u is smaller than a predetermined threshold Ty, and the amount of change ΔTf of the first temperature T2u is less than or equal to a predetermined amount of change ΔTz, then the second fault state can be determined. The amount of change ΔTf of the first temperature T2u is the amount of change in the first temperature T2u per unit time after an instruction is given to open the switching valve 7. The unit time is, for example, 10 seconds or more and 60 seconds or less. The unit time may be 30 seconds or more. The predetermined amount of change ΔTz is, for example, 5°C or more. The predetermined amount of change ΔTz may be 10°C or more.

[0073] Determination of the third failure state In the third fault condition, a portion of the first heat transfer medium is sent from the heating circuit 3 to the battery temperature control circuit 6. Since the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 does not fluctuate, the first temperature T2u does not fluctuate substantially. In addition, the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 causes the first temperature T2u to rise. Therefore, if the variation σT in the change of the first temperature T2u is smaller than a predetermined threshold Ty, and the amount of change ΔTf of the first temperature T2u is larger than a predetermined amount of change ΔTz, the third fault condition can be determined.

[0074] <Correspondence control in temperature rise control> In the temperature rise control, corrective control is performed according to the result of the fault condition determination of the switching valve 7. The corrective control according to the fault condition in the temperature rise control is explained in detail below.

[0075] 《Response control based on the first failure state》 If the judgment result is a first-order failure state, the corresponding control drives the first pump 31 and the second pump 61, and increases the output of the heater 32. If the switching valve 7 enters a first-order failure state during the temperature rise control, the heated first heat transfer medium will not be sufficiently sent from the heating circuit 3 to the battery temperature control circuit 6, and the second heat transfer medium will not be sufficiently heated. In the first-order failure state, the output of the heater 32 is increased to raise the temperature of the first heat transfer medium, thereby raising the temperature of the second heat transfer medium. With this corresponding control, the battery 10 can be heated as much as possible even if normal temperature rise control is not possible. Furthermore, the rotation speed of the pumps may be increased by driving the first pump 31 and the second pump 61 in a full-duty cycle. This increases the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6, thereby effectively heating the battery 10. By maximizing the output of the heater 32 and driving the first pump 31 and the second pump 61 in a full-duty cycle, the battery 10 can be heated more effectively.

[0076] 《Response control based on the second failure state》 In the second fault condition, the corresponding control stops the second pump 61. If the second fault condition occurs during temperature rise control, where the switching valve 7 is fixed in the fully closed position, the heated first heat transfer medium is not sent from the heating circuit 3 to the battery temperature adjustment circuit 6, and therefore the battery 10 cannot be heated by the first heat transfer medium. In the second fault condition, the battery 10 is heated by its own self-heating. By stopping the second pump 61, the second heat transfer medium does not circulate through the battery temperature adjustment circuit 6, so the heat generated by the self-heating of the battery 10 is less likely to be taken away by the second heat transfer medium. As a result, the temperature rise due to the self-heating of the battery 10 is promoted. With this corresponding control, even if normal temperature rise control is not possible, the battery 10 can be heated as much as possible. In the second fault condition, the heater 32 may also be turned OFF.

[0077] 《Response control based on the third fault state》 In the third fault condition, the corresponding control drives the first pump 31 and the second pump 61. If the switching valve 7 enters the third fault condition during temperature rise control, the flow rate of the heated first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6 decreases, resulting in insufficient heating of the second heat transfer medium. In the third fault condition, the first pump 31 and the second pump 61 are driven to increase the flow rate of the first heat transfer medium, thereby raising the temperature of the second heat transfer medium. With this corresponding control, the battery 10 can be heated as much as possible even if normal temperature rise control is not possible. Furthermore, the first pump 31 and the second pump 61 may each be driven on a full duty cycle to increase the rotation speed of the pumps. This increases the flow rate of the first heat transfer medium sent from the heating circuit 3 to the battery temperature control circuit 6, thereby effectively heating the battery 10. If the temperature rise of the battery 10 is insufficient, the output of the heater 32 may be increased further. By increasing the output of the heater 32 and raising the temperature of the first heat transfer medium, the battery 10 can be effectively heated.

[0078] Referring to Figure 3, a specific example of the processing flow for fault detection and response control in temperature rise control will be explained. When temperature rise control is started, the control device 5 issues an instruction to open the switching valve 7. It also issues an instruction to turn on the heater 32 and to drive at least one of the first pump 31 and the second pump 61. After temperature rise control is started, step S11 is executed.

[0079] Step S11 is a process to determine whether or not the switching valve 7 is faulty. In step S11, it is determined whether or not the temperature difference ΔTα between the first temperature T2u of the second heat transfer medium and the second temperature T1d of the first heat transfer medium is less than or equal to a predetermined temperature difference ΔTx. If the temperature difference ΔTα is greater than the predetermined temperature difference ΔTx, it is determined that there is a fault and the process proceeds to step S12. If the temperature difference ΔTα is less than or equal to the predetermined temperature difference ΔTx, the process proceeds to step S14 and it is determined that there is no fault. If the determination result is that there is no fault, the process proceeds to step S14a and normal temperature rise control continues. The process is repeated by returning to step S11 until the temperature rise control is completed.

[0080] Step S12 is a process to determine whether the failure state is a first failure state. In step S12, it is determined whether the variation σT of the change in the first temperature T2u is greater than or equal to a predetermined threshold Ty. If the variation σT is greater than or equal to the predetermined threshold Ty, the process proceeds to step S15 and it is determined to be a first failure state. If it is a first failure state, the process proceeds to step S15a and corresponding control is performed according to the first failure state. In step S15a, as corresponding control according to the first failure state, the first pump 31 and the second pump 61 are driven and the output of the heater 32 is increased. For example, the first pump 31 and the second pump 61 are driven in a full duty cycle and the output of the heater 32 is set to maximum. The process is repeated by returning to step S11 until the temperature rise control is completed.

[0081] In step S12, if the variation σT is smaller than a predetermined threshold Ty, the process proceeds to step S13. Step S13 is a process to determine whether the system is in a second or third fault state. In step S13, it is determined whether the change in the first temperature T2u ΔTf is less than or equal to a predetermined change ΔTz. If the change ΔTf is less than or equal to the predetermined change ΔTz, the process proceeds to step S16 and it is determined to be a second fault state. If it is a second fault state, the process proceeds to step S16a and corresponding control is performed according to the second fault state. In step S16a, the second pump 61 is stopped. Stopping the second pump 61 promotes a rise in temperature due to self-heating of the battery 10. The process returns to step S11 and is repeated until the temperature rise control is completed.

[0082] In step S13, if the change amount ΔTf is greater than a predetermined change amount ΔTz, the process proceeds to step S17 and it is determined that a third fault condition exists. If a third fault condition exists, the process proceeds to step S17a and corresponding control is performed according to the third fault condition. In step S17a, the first pump 31 and the second pump 61 are driven. For example, the first pump 31 and the second pump 61 are driven in a full-duty cycle. If the temperature rise of the battery 10 is insufficient, the output of the heater 32 may be increased to its maximum. The process is repeated, returning to step S11, until the temperature rise control is completed.

[0083] The following provides a detailed explanation of fault detection and response control in cooling control. In cooling control, fault detection only determines whether a fault exists or not; it does not determine the fault state. Furthermore, in cooling control, if a fault is detected, the same response control is performed regardless of the fault state.

[0084] <Fault detection in cooling control> 《Determination of whether or not there is a malfunction》 Fault detection in the cooling control system is performed as follows: If the temperature difference ΔTβ between the first temperature T2u of the second heat transfer medium upstream of the battery 10 and the third temperature T2d of the second heat transfer medium downstream of the chiller 62 is greater than a predetermined temperature difference ΔTv, a fault is detected. In the cooling control system, as described above, closing the switching valve 7 creates a parallel circuit between the heating circuit 3 and the battery temperature control circuit 6. If the switching valve 7 is not faulty and is in the closed state, the first heat transfer medium will not be sent from the heating circuit 3 to the battery temperature control circuit 6. Therefore, the temperature of the second heat transfer medium cooled by the chiller 62 will not be raised by the first heat transfer medium. In this example, the second heat transfer medium cooled by the chiller 62 flows from point C in the battery temperature control circuit 6 through the switching valve 7 to point D and is sent to the battery 10. If the switching valve 7 is in the closed state, the third temperature T2d of the second heat transfer medium and the first temperature T2u of the second heat transfer medium will be approximately equal. Therefore, if the temperature difference ΔTβ is less than or equal to a predetermined temperature difference ΔTv, it is determined that there is no fault. In the case of cooling control, even if the switching valve 7 is fixed in the fully closed position, a fault condition can be maintained, so it is determined that there is no fault. Even if the fault condition of the switching valve 7 being fixed in the fully closed position cannot be detected, it can be detected when the temperature rise control is performed next.

[0085] In any of the following fault conditions—the first fault where the opening of the switching valve 7 is unstable, the second fault where the switching valve 7 is fixed in the fully open position, or the third fault where the switching valve 7 is fixed in an intermediate position—the first heat transfer medium is sent from the heating circuit 3 to the battery temperature control circuit 6. As a result, the temperature of the second heat transfer medium rises due to the first heat transfer medium. Also, when the switching valve 7 is open, the second heat transfer medium cooled by the chiller 62 passes through the heating circuit 3, so the temperature of the second heat transfer medium rises from when it is cooled by the chiller 62 until it is sent to the battery 10. Therefore, in any of the fault conditions, the temperature difference ΔTβ becomes large. Accordingly, if the temperature difference ΔTβ is greater than a predetermined temperature difference ΔTv, a fault is determined to exist.

[0086] The temperature difference ΔTβ is an absolute value. A given temperature difference ΔTv is, for example, 10°C. A given temperature difference ΔTv may also be 5°C.

[0087] The third temperature T2d of the second heat transfer medium is the temperature of the second heat transfer medium cooled by the chiller 62. Specifically, it is the temperature of the second heat transfer medium discharged from the first heat exchange section 62a. The third temperature T2d can be estimated by calculating it from the heat exchange rate of the chiller 62. The heat exchange rate of the chiller 62 can be determined by calculating the amount of heat transferred from the second heat transfer medium in the first heat exchange section 62a to the third heat transfer medium in the second heat exchange section 62b, based on the temperature difference of the third heat transfer medium before and after it passes through the second heat exchange section 62b.

[0088] The temperature of the third heat transfer medium before it passes through the chiller 62 is obtained by the first temperature sensor 47a. The temperature of the third heat transfer medium after it passes through the chiller 62 is obtained by the second temperature sensor 47b.

[0089] In this example, the third temperature T2d of the second heat transfer medium is an estimated value calculated from the heat exchange rate of the chiller 62. Unlike this example, the third temperature T2d of the second heat transfer medium may be an actual value measured by a temperature sensor. In this case, the temperature sensor for measuring the third temperature T2d of the second heat transfer medium is installed near the outlet of the first heat exchange section 62a from which the second heat transfer medium is discharged.

[0090] <Correspondence control in cooling control> In the event of a malfunction, the corrective control drives the first pump 31 and the second pump 61, and increases the output of the chiller 62. If the switching valve 7 malfunctions during cooling control, the first heat transfer medium is sent from the heating circuit 3 to the battery temperature control circuit 6, resulting in insufficient cooling of the second heat transfer medium. Furthermore, since the second heat transfer medium cooled by the chiller 62 passes through the heating circuit 3, a delay occurs before the second heat transfer medium cooled by the chiller 62 reaches the battery 10. In the event of a malfunction, the output of the chiller 62 is increased to lower the temperature of the second heat transfer medium. This corrective control allows the battery 10 to be cooled as much as possible even when normal cooling control is not possible. In addition, the first pump 31 and the second pump 61 may each be driven on a full duty cycle to increase the pump rotation speed. This reduces the delay before the second heat transfer medium cooled by the chiller 62 reaches the battery 10, and allows the battery 10 to be cooled effectively.

[0091] Furthermore, when performing corresponding control, if the air conditioning heating is ON and the heater 32 is ON, the heater 32 may be turned OFF to turn off the heating. This prevents the second heat transfer medium, which passes through the heating circuit 3, from being heated by the heater 32. When the control device 5 turns off the heater 32, it may also notify the occupants that the heating will be turned off. This notification may be carried out, for example, by at least one of a visual announcement and an auditory announcement. In addition, when turning off the heater 32, the control device 5 may also turn off the heater 32 if the temperature inside the vehicle is such that the occupants will not feel uncomfortable even if the heating is turned off.

[0092] Referring to Figure 4, a specific example of the processing flow for fault detection and response control in cooling control will be explained. When starting cooling control, an instruction is given to close the switching valve 7. At the same time, an instruction is given to turn on the chiller 62 and drive the second pump 61. After starting cooling control, step S21 is executed.

[0093] Step S21 is a process to determine whether or not the switching valve 7 is faulty. In step S21, it is determined whether or not the temperature difference ΔTβ between the first temperature T2u of the second heat transfer medium and the third temperature T2d of the second heat transfer medium is less than or equal to a predetermined temperature difference ΔTv. If the temperature difference ΔTβ is greater than the predetermined temperature difference ΔTv, it is determined that there is a fault and the process proceeds to step S23. If the temperature difference ΔTβ is less than or equal to the predetermined temperature difference ΔTv, the process proceeds to step S22 and it is determined that there is no fault. If the determination result is that there is no fault, the process proceeds to step S22a and normal cooling control continues. The process returns to step S21 and is repeated until the cooling control is completed.

[0094] In step S21, if the temperature difference ΔTβ is greater than a predetermined temperature difference ΔTv, the process proceeds to step S23 and a fault is determined. If a fault is found, the process proceeds to step S23a and corrective control is performed. In step S23a, the corrective control involves driving the first pump 31 and the second pump 61. For example, the first pump 31 and the second pump 61 are each driven in a full-duty cycle. The process returns to step S21 and is repeated until the cooling control is completed. [Explanation of Symbols]

[0095] 1. Electric Vehicle 10 batteries, 10t battery temperature sensor 11 Front grille, 12 Fan 2. Air conditioning unit 2i inlet, 2o outlet 26 Heater core, 27 Evaporator 28 Air Mix Door, 29 Blower 3. Heating circuit 31 First pump, 32 Heater, 33 Reserve tank 34 heat exchanger, 34a first heat exchange section, 34b second heat exchange section 35a First temperature sensor, 35b Second temperature sensor 4. Heat pump circuit 4a First channel, 4b Second channel, 4c Third channel 40 Flow path switching valve, 41 Compressor, 42 Capacitor 44 Heating expansion valve, 45 Accumulator 46. ​​Expansion valve for air conditioning 47a First temperature sensor, 47b Second temperature sensor 49. Expansion valve for chiller 5 Control device 6 Battery temperature adjustment circuit 61 Second pump 62 Chiller, 62a First heat exchanger, 62b Second heat exchanger 65 Temperature Sensor 7. Switching valve

Claims

1. A heating circuit through which the first heat transfer medium for raising the temperature of the heater core is circulated, A battery temperature control circuit in which a second heat transfer medium is circulated to regulate the temperature of the battery, A switching valve that switches the connection state between the heating circuit and the battery temperature control circuit, The system includes a control device that performs temperature rise control or cooling control for the battery, The aforementioned heating circuit is A first pump for circulating the first heat transfer medium, The system includes a heater for heating the first heat transfer medium, The aforementioned battery temperature control circuit is A second pump for circulating the second heat transfer medium, The system includes a chiller for cooling the second heat transfer medium, The switching valve is configured to connect the heating circuit and the battery temperature control circuit when open, and to disconnect the heating circuit and the battery temperature control circuit when closed. The control device determines whether the switching valve is faulty during the temperature rise control or the cooling control, and performs corresponding control according to the determination result. The temperature rise control involves opening the switching valve, turning on the heater, and driving at least one of the first pump and the second pump. The cooling control involves closing the switching valve, turning on the chiller, and driving the second pump. The determination of the fault is made based on the change in temperature of the second heat transfer medium upstream of the battery. Electric vehicle.

2. The electric vehicle according to claim 1, wherein if it is determined that the switching valve is fixed in the fully closed position during the temperature rise control, control is performed to stop the second pump.

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