Heat medium circulation device for vehicle

Abstract

To provide a heat medium circulation device for a vehicle which can raise a temperature of a secondary battery while suppressing deterioration of the secondary battery even under an extremely low temperature environment, and can quickly and efficiently heat the inside of a cabin.SOLUTION: A heat medium circulation device for a vehicle includes: a heating circuit in which a heat medium supplied to a heater core is circulated; a battery temperature adjustment circuit for circulating the heat medium supplied to the secondary battery; a circuit switching valve for switching a connection state between the heating circuit and the battery temperature adjustment circuit; a sensor for measuring the temperature of the heat medium having passed through the heater core; and a controller for controlling the circuit switching valve so as to make the secondary battery supply a mixed heat medium in which the heat medium having passed through the heater core and the heat medium having passed through the secondary battery are mixed, on the basis of the measurement temperature of the sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a heat medium circulating device for a vehicle including a heating circuit through which a heat medium supplied to a heater core is circulated, and a battery temperature regulating circuit through which a heat medium supplied to a secondary battery is circulated. [Background technology]

[0002] Patent Document 1 discloses a thermal management system for an electric vehicle. The thermal management system includes a battery-side coolant circuit, a heating-side coolant circuit, and a circuit connection part.

[0003] The battery-side coolant circuit is a circuit that circulates coolant that regulates the temperature of the battery. The battery-side coolant circuit includes a chiller and a battery. The chiller cools the coolant by heat exchange between a low-pressure refrigerant and the coolant. The battery supplies charged electric power to electric in-vehicle devices such as an electric motor for driving the vehicle.

[0004] The heating side coolant circuit is a circuit that circulates coolant that heats the blown air in a heating mode that heats the vehicle interior. The heating side coolant circuit includes a water-refrigerant heat exchanger, a heating device, and a heater core. The water-refrigerant heat exchanger heats the coolant by heat exchange between the high-pressure refrigerant and the coolant. The heating device heats the coolant. The heater core warms the blown air by heat exchange between the heated coolant and the blown air.

[0005] The circuit connection part connects the battery side coolant circuit and the heating side coolant circuit. The circuit connection part forms a circulation path in which coolant flows in the following order: chiller, battery, heater core, and chiller. In this circulation path, coolant cooled by the chiller passes through the battery, and the temperature of the coolant rises due to the heat of the battery. The heated coolant passes through the heater core, and the temperature of the coolant drops due to heat exchange in the heater core. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2019-119369 A Summary of the Invention [Problem to be solved by the invention]

[0007] In extremely low temperature environments such as cold regions and winter, the temperature of secondary batteries becomes low. A secondary battery that is too cold has a lower voltage value than a secondary battery at room temperature. Therefore, in extremely low temperature environments, it is desirable to raise the temperature of the secondary battery to about room temperature.

[0008] In Patent Document 1, if the cooling water that has passed through the heater core is supplied to the battery without being cooled by a chiller, the battery can be heated by the cooling water even if the temperature of the cooling water is lowered by heat exchange in the heater core. However, in an extremely low temperature environment, the temperature of the cooling water supplied to the heater core may become higher due to the cooling water being heated by the heating device or the like, so that even if the temperature is lowered by heat exchange in the heater core, the temperature of the cooling water supplied to the battery may be too high. If the temperature of the cooling water supplied to the battery is too high, the battery deteriorates. In order to avoid deterioration of the battery, the upper limit value of the temperature of the cooling water that can be supplied to the battery is limited. As a result, when the cooling water that has passed through the heater core is supplied to the battery without being cooled by a chiller, the upper limit value of the temperature of the cooling water supplied to the heater core is limited to a temperature that does not exceed the upper limit value of the temperature of the cooling water that can be supplied to the battery after passing through the heater core. In this case, the upper limit value of the temperature of the hot air is limited, and the vehicle interior cannot be heated quickly and efficiently in an extremely low temperature environment. Although it is possible to lower the temperature of the cooling water supplied to the secondary battery by the chiller as in Patent Document 1, the cruising range is shortened because battery power is consumed to produce the above-mentioned low-pressure refrigerant in the chiller.

[0009] One object of the present invention is to provide a heat medium circulation device for a vehicle that can raise the temperature of a secondary battery while suppressing deterioration of the secondary battery, even in an extremely low temperature environment, and can quickly and efficiently warm the interior of the vehicle. [Means for solving the problem]

[0010] A heat medium circulating device for a vehicle according to one aspect of the present invention is a heating circuit in which a heat medium supplied to the heater core is circulated; a battery temperature adjustment circuit in which a heat medium supplied to the secondary battery is circulated; a circuit switching valve that switches a connection state between the heating circuit and the battery temperature adjustment circuit; a sensor for measuring a temperature of the heat medium passing through the heater core; and a controller that controls the circuit switching valve to supply a mixed heat medium, which is a mixture of the heat medium that has passed through the heater core and the heat medium that has passed through the secondary battery, to the secondary battery based on the temperature measured by the sensor. Effect of the Invention

[0011] When the heater is ON in an extremely low temperature environment, the temperature of the heat medium that has passed through the heater core is somewhat high, although it is lowered by heat exchange in the heater core. The temperature of the heat medium that has passed through the secondary battery is somewhat low, since it is lowered by heat exchange in the secondary battery. The heat medium circulation device for a vehicle includes a circuit switching valve and a controller, and can supply a mixed heat medium, which is a mixture of the heat medium that has passed through the heater core and the heat medium that has passed through the secondary battery, to the secondary battery. The temperature of the mixed heat medium is lower than the temperature of the heat medium that has passed through the heater core. Therefore, even if the temperature of the heat medium that has passed through the heater core exceeds the upper limit of the temperature of the heat medium that can be supplied to the secondary battery, the heat medium circulation device for a vehicle can make the temperature of the mixed heat medium equal to or lower than the upper limit. Therefore, the heat medium circulation device for a vehicle can increase the temperature of the secondary battery while suppressing deterioration of the secondary battery. In addition, since the heat medium circulation device for a vehicle can make the temperature of the mixed heat medium equal to or lower than the upper limit, the temperature of the heat medium supplied to the heater core can be made to exceed the upper limit. Therefore, the heat medium circulation device for a vehicle can increase the temperature of the hot air heated by the heater core. Therefore, the heat medium circulation device for a vehicle can quickly and efficiently heat the interior of the vehicle even in an extremely low temperature environment. The heat medium circulation device for a vehicle can quickly and efficiently heat the interior of the vehicle even in an extremely low temperature environment with a simple configuration including a circuit switching valve and a controller, and can suppress deterioration of the secondary battery, thereby reducing costs. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a configuration diagram showing a heat medium circulating device for a vehicle according to an embodiment. [Diagram 2] FIG. 2 is a flowchart showing a first control procedure in the heat medium circulating device for a vehicle according to the embodiment. [Diagram 3] FIG. 3 is a flowchart showing a second control procedure in the heat medium circulating device for a vehicle according to the embodiment. [Figure 4] FIG. 4 is a graph showing the opening degree of the circuit switching valve in step S14 of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] <<Embodiment>> [Heat medium circulating device for vehicle] An embodiment of a heat medium circulating device 1 for a vehicle of the present invention will be described with reference to Fig. 1 to Fig. 4. As shown in Fig. 1, the heat medium circulating device 1 for a vehicle of the embodiment includes a heating circuit 3 and a battery temperature adjustment circuit 6. The heating circuit 3 circulates the heat medium supplied to a heater core 32. The battery temperature adjustment circuit 6 circulates the heat medium supplied to a secondary battery 60. The outline arrows in Fig. 1 indicate the direction in which the heat medium flows. One of the features of the heat medium circulating device 1 for a vehicle of the embodiment is that it further includes a circuit switching valve 7, a second temperature sensor 46, and a controller 4. A vehicle 100 equipped with the heat medium circulating device 1 for a vehicle of the present embodiment is a BEV (Battery Electric Vehicle).

[0014] [Heating circuit] In the heating circuit 3, the heat medium supplied to the heater core 32 is circulated. The heater core 32 heats the air by heat exchange between the heat medium passing through the heater core 32 and the air. That is, the heat medium supplied to the heater core 32 is a heat medium with a high temperature. The heat medium supplied to the heater core 32 is a heat medium that has passed through the condenser 30. This heat medium is, for example, an antifreeze such as long life coolant (LLC). The condenser 30 is provided so as to be in contact with another condenser 23. The condenser 30 heats the heat medium passing through the condenser 30 by the heat of the condenser 23 being transferred thereto. The condenser 23 is provided in a heat pump circuit (not shown). The heat pump circuit has a circuit in which the other heat medium circulates in the order of an external condenser, a solenoid valve, an accumulator, an electric compressor, the condenser 23, an electromagnetic expansion valve, and the external condenser. The other heat medium has a high temperature by being heated by the electric compressor. The other heat medium is, for example, a hydrofluorocarbon such as R134a. Heat of the other heat medium is transferred to the heat medium supplied to the heater core 32 by the condenser 23 and the condenser 30. Thus, the heat medium supplied to the heater core 32 is heated and the other heat medium is cooled. The heat medium supplied to the heater core 32 may be further heated by a heater 31, which will be described later. The heater core 32 is provided downstream of the evaporator 27, which will be described later. The heater core 32 is provided in the air conditioning unit 2A.

[0015] The air conditioning unit 2A is also called, for example, HVAC (Heating, Ventilation, and Air Conditioning). In addition to the heater core 32, the air conditioning unit 2A includes a blower 29, an evaporator 27, and an air mix door 28. The blower 29 draws air from outside the vehicle compartment into the air conditioning unit 2A through the intake port 2B, and discharges the air from the air conditioning unit 2A into the vehicle compartment through the outlet port 2C. The evaporator 27 evaporates the heat medium atomized by expansion due to reduced pressure. The air passing through the evaporator 27 is cooled by heat exchange with the heat medium. That is, the other heat medium supplied to the evaporator 27 is a heat medium with a low temperature. The heat medium supplied to the evaporator 27 is cooled by, for example, an electromagnetic expansion valve (not shown). The evaporator 27 is provided downstream of the blower 29. The air mix door 28 is arranged to be able to swing or slide between the evaporator 27 and the heater core 32. The air mix door 28 adjusts the mixing ratio of the cool air from the evaporator 27 and the hot air from the heater core 32 depending on the opening degree of the air mix door 28.

[0016] The heating circuit 3 includes a pump 34, a condenser 30, a heater 31, a first temperature sensor 45, a second temperature sensor 46, and a reserve tank 33. The heater 31 is not an essential component. The pump 34 circulates the heat medium in the heating circuit 3. The heat medium flows through the condenser 30, the heater 31, the first temperature sensor 45, the heater core 32, the second temperature sensor 46, the circuit switching valve 7, the reserve tank 33, the pump 34, and the condenser 30 in this order. The pump 34 is an electric pump. The pump 34 is provided in the middle of the flow path from the reserve tank 33 to the condenser 30 in the heat medium circulation path. The condenser 30 is as described above. The heater 31 heats the heat medium. The heater 31 is, for example, a high voltage water heater (HVH: High Voltage Heater). The first temperature sensor 45 measures the temperature of the heat medium flowing from the condenser 30 to the heater core 32. The first temperature sensor 45 is provided in the heat medium circulation path, midway through the flow path from the condenser 30 to the heater core 32. When the heating circuit 3 has a heater 31, the first temperature sensor 45 is provided in the heat medium circulation path, midway through the flow path from the heater 31 to the heater core 32. The second temperature sensor 46 measures the temperature of the heat medium flowing from the heater core 32 to the circuit switching valve 7. The second temperature sensor 46 is provided in the heat medium circulation path, midway through the flow path from the heater core 32 to the circuit switching valve 7. The reserve tank 33 temporarily stores the heat medium circulating through the heating circuit 3.

[0017] [Battery temperature adjustment circuit] The battery temperature adjustment circuit 6 circulates a heat medium supplied to a secondary battery 60. The secondary battery 60 is used to drive a BEV. The heat medium supplied to the secondary battery 60 adjusts the temperature of the secondary battery 60. The battery temperature adjustment circuit 6 has a pump 61, a temperature sensor 62, and a chiller 63. Although the chiller 63 is shown in FIG. 1, the chiller 63 is not an essential component in this example.

[0018] The pump 61 circulates the heat medium in the battery temperature adjustment circuit 6. The heat medium flows through the secondary battery 60, the circuit switching valve 7, and the secondary battery 60 in this order. The pump 61 is an electric pump. The pump 61 is provided in the middle of the flow path from the circuit switching valve 7 to the temperature sensor 62 in the heat medium circulation path. The temperature sensor 62 measures the temperature of the heat medium supplied to the secondary battery 60. The temperature sensor 62 is provided in the middle of the flow path from the pump 61 to the secondary battery 60 in the heat medium circulation path. The chiller 63 cools the heat medium that has passed through the secondary battery 60. The chiller 63 is provided so as to be in contact with another chiller 81. Another heat medium passes through the chiller 81. The other heat medium is the same as the other heat medium that flows through the heat pump circuit described above. The heat pump circuit has a circuit that circulates through the external condenser, the electromagnetic expansion valve, the chiller 81, the accumulator, the electric compressor, the condenser 23, the expansion valve, and the external condenser in this order. The other heat medium has a low temperature by being cooled by the electromagnetic expansion valve. The heat of the heat medium that has passed through the secondary battery 60 is transferred to the other heat medium by the chiller 63 and the chiller 81. Thus, the temperature of the heat medium that has passed through the secondary battery 60 is lowered. The chiller 63 is provided in the middle of the flow path from the secondary battery 60 to the circuit switching valve 7 in the heat medium circulation path. In the battery temperature adjustment circuit 6, in order to suppress an increase in the pressure of the heat medium that flows, when the pressure of the heat medium that has passed through the secondary battery 60 reaches a predetermined level or higher, a part of the heat medium flows into the reserve tank 33. In the battery temperature adjustment circuit 6 of this example, a chiller is not provided in the middle of the flow path from the circuit switching valve 7 to the secondary battery 60 in the heat medium circulation path. In the battery temperature adjustment circuit 6 of this example, a battery heater that is independent of the heat medium for heating the secondary battery 60 is not provided.

[0019] [Circuit switching valve] The circuit switching valve 7 switches the connection state between the heating circuit 3 and the battery temperature adjustment circuit 6. The circuit switching valve 7 connects the middle of the flow path from the second temperature sensor 46 to the reserve tank 33 in the circulation path of the heat medium of the heating circuit 3 to the middle of the flow path from the secondary battery 60 to the pump 61 in the circulation path of the heat medium of the battery temperature adjustment circuit 6. The circuit switching valve 7 switches from the following state (1) to state (3) by adjusting the opening degree by the controller 4 described later. The circuit switching valve 7 of this example is a four-way valve that can branch the flow path in four directions. The four-way valve can be a known four-way valve (for example, JP 2013-238310 A, JP 2020-200902 A). The circuit switching valve 7 is not limited to a four-way valve, and may be, for example, a five-way valve or a six-way valve as long as the flow path can be branched in four or more directions.

[0020] (1) The circuit switching valve 7 makes the heating circuit 3 and the battery temperature adjustment circuit 6 a parallel circuit independent of each other. The circuit switching valve 7 prevents the heat medium circulating in the heating circuit 3 from flowing into the battery temperature adjustment circuit 6, and prevents the heat medium circulating in the battery temperature adjustment circuit 6 from flowing into the heating circuit 3. That is, the parallel circuit is a circuit in which the heat medium circulates independently in a circuit of the pump 34, the condenser 30, the heater 31, the heater core 32, point A, the circuit switching valve 7, point B, the reserve tank 33, and the pump 34, and a circuit of the pump 61, the secondary battery 60, the chiller 63, point C, the circuit switching valve 7, point D, and the pump 61. The heat medium at point A that has passed through the heater core 32 is supplied to the heater core 32 through point B without being supplied to the secondary battery 60 through point D, and the heat medium at point C that has passed through the secondary battery 60 is supplied to the secondary battery 60 through point D without being supplied to the heater core 32 through point B. The temperature of the heat medium flowing from the condenser 30 to the heater core 32 is higher than the temperature of the heat medium flowing from the heater core 32 to the condenser 30 .

[0021] (2) The circuit switching valve 7 makes the heating circuit 3 and the battery temperature adjustment circuit 6 a series circuit. The circuit switching valve 7 makes the heat medium flowing through the heating circuit 3 flow to the battery temperature adjustment circuit 6, and the heat medium flowing through the battery temperature adjustment circuit 6 flow to the heating circuit 3. That is, the series circuit is a series of circuits including the pump 34, the condenser 30, the heater 31, the heater core 32, point A, the circuit switching valve 7, point D, the pump 61, the secondary battery 60, the chiller 63, point C, the circuit switching valve 7, the reserve tank 33, and the pump 34. The heat medium at point A that has passed through the heater core 32 is supplied to the secondary battery 60 through point D without passing through point B, and the heat medium at point C that has passed through the secondary battery 60 is supplied to the heater core 32 through point B without passing through point D. The temperature of the heat medium flowing from the condenser 30 to the heater core 32 is higher than the temperature of the heat medium flowing from the heater core 32 to the secondary battery 60, and the temperature of the heat medium flowing from the heater core 32 to the secondary battery 60 is higher than the temperature of the heat medium flowing from the secondary battery 60 to the condenser 30.

[0022] (3) The circuit switching valve 7 makes the heating circuit 3 and the battery temperature adjustment circuit 6 a mixed circuit. The circuit switching valve 7 makes the heat medium flowing through the heating circuit 3 flow to the heating circuit 3 and the battery temperature adjustment circuit 6, and makes the heat medium flowing through the battery temperature adjustment circuit 6 flow to the battery temperature adjustment circuit 6 and the heating circuit 3. That is, the mixed circuit is a circuit that can simultaneously discharge a part of the heat medium at point A and a part of the heat medium at point C to point D, and discharge the remaining part of the heat medium at point A and the remaining part of the heat medium at point C to point B. A part of the heat medium at point A that has passed through the heater core 32 is mixed with a part of the heat medium at point C that has passed through the secondary battery 60, and the remaining part of the heat medium at point A that has passed through the heater core 32 and the remaining part of the heat medium at point C that has passed through the secondary battery 60 are mixed. A mixed heat medium obtained by mixing a part of the heat medium at point A that has passed through the heater core 32 and a part of the heat medium at point C that has passed through the secondary battery 60 is supplied to the secondary battery 60 through point D. A mixed heat medium obtained by mixing the remaining part of the heat medium at point A that has passed through the heater core 32 and the remaining part of the heat medium at point C that has passed through the secondary battery 60 is supplied to the heater core 32 through point B. The temperature of the heat medium flowing from the condenser 30 to the heater core 32 is higher than the temperature of the heat medium flowing from the heater core 32 to the circuit switching valve 7, and the temperature of the heat medium flowing from the heater core 32 to the circuit switching valve 7 is higher than the temperature of the mixed heat medium.

[0023] [Controller] The controller 4 controls the circuit switching valve 7 to transition to any one of the above states (1) to (3). The controller 4 controls the pump 34 and the heater 31 of the heating circuit 3, the pump 61 of the battery temperature adjustment circuit 6, the electric compressor, and the electromagnetic expansion valve.

[0024] The controller 4 is configured by an electronic control unit (ECU). The ECU typically includes a processor and a memory. The processor is, for example, a CPU. The memory stores control programs to be executed by the processor and various data. The controller 4 is operated by the processor executing the control programs stored in the memory. The controller 4 also performs necessary calculation processing and judgment processing according to the control programs stored in the memory.

[0025] (First control procedure) 1 and 2, a first control procedure by the controller 4 will be described. The controller 4 controls the circuit switching valve 7 so as to establish the parallel circuit in the above state (1).

[0026] In step S01, it is determined whether or not the temperature TB of the secondary battery 60 is lower than the temperature X. The temperature TB of the secondary battery 60 can be acquired by a temperature sensor (not shown) provided in the secondary battery 60. The temperature X is, for example, 0° C. If the temperature TB of the secondary battery 60 is lower than the temperature X, the temperature of the secondary battery 60 needs to be increased.

[0027] If the conditions of step S01 are satisfied, in step S02, the controller 4 controls the circuit switching valve 7 to set the series circuit in the state (2). The heat medium flowing through the heating circuit 3 is heated in the condenser 30 by heat exchange with the other heat medium heated by the compressor. This heated heat medium flows through the heater core 32, point A, the circuit switching valve 7, and point D in this order, and then flows to the secondary battery 60. The heat medium that has passed through the secondary battery 60 flows through the chiller 63, point C, the circuit switching valve 7, and point B in this order, and then flows to the condenser 30. At this time, no heat medium flows through the chiller 81, and the chiller 81 is not cooled. Therefore, the heat medium is not cooled in the chiller 63.

[0028] In step S03, the controller 4 determines whether or not there is a heating request. Whether or not there is a heating request can be determined by whether or not a signal to turn on the heating switch has been sent to the controller 4. When there is a heating request, the temperature of the separate heat medium heated by the compressor becomes higher than when there is no heating request. Therefore, the temperature of the heat medium heated by heat exchange in the condenser 30 becomes higher. That is, the temperature of the heat medium flowing to the secondary battery 60 becomes higher.

[0029] If the condition of step S03 is satisfied, in step S04, the controller 4 judges whether the temperature TMB of the heat medium supplied to the secondary battery 60 exceeds the temperature Y. The temperature TMB of the heat medium supplied to the battery is temperature A or temperature D. Temperature A is the temperature of the heat medium at point A. Temperature A is considered to be the temperature acquired by the second temperature sensor 46. Temperature D is the temperature of the heat medium at point D. Temperature D is considered to be the temperature acquired by the temperature sensor 62. Temperature Y is the upper limit of the temperature of the heat medium at which the secondary battery 60 does not deteriorate even if it is supplied to the secondary battery 60. Temperature Y is, for example, 45°C + α. α is the temperature of the heat medium dissipated when it flows through the flow path. α is obtained in advance. In this example, in step S04, the controller 4 judges whether the temperature D exceeds the temperature Y.

[0030] If the condition of step S04 is satisfied, in step S05, the controller 4 acquires the temperature A. If the temperature TMB is the temperature A in step S04, step S05 is unnecessary.

[0031] In step S06, the controller 4 calculates the flow rate A, the temperature C, and the flow rate C. The flow rate A is the flow rate of the heat medium at point A. The flow rate A is calculated based on the duty ratio of the pump 34 of the heating circuit 3 and the pressure loss of the heating circuit 3. The duty ratio of the pump 34 of the heating circuit 3 is appropriately selected according to the use mode of the heating circuit 3. The pressure loss of the heating circuit 3 is known. The temperature C is the temperature of the heat medium at point C. The temperature C can be calculated based on the temperature D and the temperature change of the secondary battery 60. The temperature C is calculated, for example, by the difference between the temperature D and the amount of heat transferred to the secondary battery 60. The amount of heat transferred to the secondary battery 60 is calculated by the product of the temperature change of the secondary battery 60 and a coefficient. The coefficient is appropriately selected according to the heat transfer efficiency from the heat medium to the secondary battery 60 and the number of cells of the secondary battery 60. The temperature change of the secondary battery 60 can be acquired by a temperature sensor (not shown) provided in the secondary battery 60. The heat transfer efficiency and the number of cells are known. The flow rate C is the flow rate of the heat medium at point C. The flow rate C is determined based on the duty ratio of the pump 61 of the battery temperature adjustment circuit 6 and the pressure loss of the secondary battery 60. The duty ratio of the pump 61 of the battery temperature adjustment circuit 6 can be appropriately selected. The pressure loss of the secondary battery 60 is known.

[0032] In step S07, the opening degree of the circuit switching valve 7 is calculated. In step S07, the opening degree is calculated so that the temperature of the mixed heat medium, which is a mixture of a part of the heat medium that has passed through the heater core 32 and a part of the heat medium that has passed through the secondary battery 60 and is supplied to the secondary battery 60, is equal to or lower than temperature Y. The opening degree of the circuit switching valve 7 is calculated by the following formula. Formula: Opening degree = 100 - {(target heat amount a - heat amount C) / (heat amount C + heat amount A)} x 100 The target heat quantity a can be calculated using the target temperature of the heat medium at point D and the temperature D. More specifically, the target heat quantity a can be calculated using the difference between the target temperature of the heat medium at point D and the temperature D, the flow rate D, the density of the heat medium, and the specific heat of the heat medium. The flow rate D is calculated based on the duty ratio of the pump 61 of the battery temperature adjustment circuit 6. The heat quantity C can be calculated using the temperature C, the flow rate C, the density of the heat medium, and the specific heat of the heat medium. The heat quantity A can be calculated using the temperature A, the flow rate A, the density of the heat medium, and the specific heat of the heat medium. There may be a difference between the flow rate of the heat medium from point A to point D and the flow rate of the heat medium from point C to point D. In that case, the opening degree of the circuit switching valve 7 may be calculated by the following equation using constants γ and β as a correction term for the flow rate difference. Formula: Opening degree = 100 - [(target heat amount a - heat amount C x constant γ) / {(heat amount C + heat amount A) - (heat amount C x constant β)}] x 100 The constants γ and β can be appropriately selected depending on the flow rate difference.

[0033] In step S08, the controller 4 operates the circuit switching valve 7 so as to have the opening calculated in step S07. As a result, the mixed circuit is in the above state (3).

[0034] In step S09, it is determined whether the temperature D is constant and whether the temperature TMH is higher than the target temperature Ta. The temperature D being constant means, for example, that the temperature D has not substantially changed for five minutes. The temperature TMH is the temperature of the heat medium supplied to the heater core 32, and is the temperature acquired by the first temperature sensor 45. The target temperature Ta is the temperature of the heat medium supplied to the heater core 32, which is determined by the heating set temperature.

[0035] If the condition in step S09 is satisfied, the controller 4 ends the control.

[0036] If the condition in step S01 is not satisfied, the controller 4 ends the control. That is, the parallel circuit in the above state (1) is maintained.

[0037] If the condition of step S03 is not satisfied, the controller 4 ends the control. That is, the series circuit in state (2) is maintained. When there is no heating request, the temperature of the other heat medium heated by the compressor is lower than when there is a heating request. Therefore, the temperature of the heat medium heated by heat exchange in the condenser 30 is lower. That is, the temperature of the heat medium flowing to the secondary battery 60 is low. Therefore, the controller 4 does not need to perform control from step S04 onwards.

[0038] If the condition of step S04 is not satisfied, step S04 is repeated until the condition of step S04 is satisfied, that is, the series circuit in the above state (2) is maintained.

[0039] If the condition of step S09 is not satisfied, steps S07 to S09 are repeated until the condition of step S09 is satisfied.

[0040] [Second control procedure] The second control procedure will be described with reference to Figures 1 and 3. Steps S21 to S25 are the same as steps S01 to S05.

[0041] In step S26, the controller 4 controls the circuit switching valve 7 to have a set opening degree. The set opening degree will be described with reference to FIG.

[0042] The horizontal axis in FIG. 4 is the opening (%) of the circuit switching valve 7. The left end of the horizontal axis is 0% opening, and the right end is 100% opening. The vertical axis on the left is the flow rate (m 3 / s). The right vertical axis is the flow rate (m 3 / s). The solid lines indicate the flow rate from point A to point D for each opening. This flow rate is the flow rate when the temperature of the heat medium is 80°C and the pump 34 of the heating circuit 3 is at maximum output for each opening. The dashed lines indicate the flow rate from point C to point D for each opening. The flow rate is the flow rate when the temperature of the heat medium is 0°C and the pump 61 of the battery temperature adjustment circuit 6 is at maximum output for each opening. The set opening is the opening at which the sum of the flow rate from point A to point D and the flow rate from point C to point D is the largest in FIG. 4, that is, the opening at the intersection of the solid line and the dashed line. This set opening is the opening at which the temperature of the mixed heat medium, which is a mixture of a part of the heat medium that has passed through the heater core 32 and a part of the heat medium that has passed through the secondary battery 60 and is supplied to the secondary battery 60, is equal to or lower than temperature Y.

[0043] In step S27, temperature A' is calculated. Temperature A' is the temperature of the heat medium at point A required to bring the heat medium at point D to the target temperature when the opening is set. Temperature A' is calculated using the following formula. Formula: Target temperature for temperature D = {(Temperature A' x Flow rate AD + Temperature C x Flow rate CD) / (Flow rate AD + Flow rate CD)} Flow rate AD is the flow rate flowing from point A to point D at the above set opening. Flow rate CD is the flow rate flowing from point C to point D at the above set opening. Flow rate AD and flow rate CD can be obtained from the graph in Figure 4. There may be a difference in temperature of the heat medium from point A to point D and the heat medium from point C to point D. In that case, temperature A' may be obtained by the following equation using a constant θ as a correction term for that temperature difference. Formula: Target temperature for temperature D = {(Temperature A' x Flow rate AD + Temperature C x Flow rate CD) / (Flow rate AD + Flow rate CD)} x Constant θ The constant θ can be appropriately selected depending on the temperature difference.

[0044] In step S28, the controller 4 adjusts the output of the heater 31. The output of the heater 31 is adjusted so that the amount of heat calculated using the difference between temperature A' and temperature A, the flow rate A, the density of the heat medium, and the specific heat of the heat medium is applied to the heat medium.

[0045] Step S29 is the same as step S09. If the condition of step S29 is not satisfied, steps S27 to S29 are repeated until the condition of step S29 is satisfied.

[0046] Unlike this example, in step S27, the controller 4 may adjust the duty ratio of the pumps 34, 61 while keeping the output of the heater 31 constant, rather than adjusting the output of the heater 31. By changing the duty ratio of the pumps 34, 61, the flow rate of the heat medium can be changed.

[0047] By performing these steps, the heat medium circulating device 1 for a vehicle can raise the temperature of the secondary battery 60 while suppressing deterioration of the secondary battery 60, since the temperature of the mixed heat medium supplied to the heater core 32 can be set to be equal to or lower than the upper limit value even if the temperature of the heat medium supplied to the heater core 32 exceeds the upper limit value of the temperature of the heat medium that can be supplied to the secondary battery 60. Furthermore, since the heat medium circulating device 1 for a vehicle can set the temperature of the mixed heat medium to be equal to or lower than the upper limit value, the temperature of the heat medium supplied to the heater core 32 can be set to a temperature exceeding the upper limit value. Therefore, the heat medium circulating device 1 for a vehicle can raise the temperature of the hot air heated by the heater core 32. Therefore, the heat medium circulating device 1 for a vehicle can quickly and efficiently heat the interior of the vehicle even in an extremely low temperature environment.

[0048] <<Variation>> In the modified heat medium circulating device 1 for a vehicle, the heat medium may be cooled by the chiller 63. In some extremely low temperature environments, the temperature of the heat medium supplied to the heater core 32 may be raised too high, and as a result, even if the heat medium flowing through point A and the heat medium flowing through point C are mixed as in the first and second control procedures described above, the temperature of the mixed heat medium supplied to the secondary battery 60 may not become equal to or lower than temperature Y. In such cases, the heat medium that has passed through the secondary battery 60 is cooled by the chiller 63, and the cooled heat medium flowing through point C and the heat medium flowing through point A are mixed, so that the temperature of the mixed heat medium supplied to the secondary battery 60 can be made equal to or lower than temperature Y.

[0049] The present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0050] 100 vehicles 1 Heat transfer medium circulation device for vehicles 2A Air Conditioning Unit 2B Air Intake 2C Air outlet 23 Capacitor 27 Evaporator 28 Air Mix Door 29 Blower 3 Heating circuit 30 Capacitor 31 Heater 32 Heater core 33 Reserve Tank 34 Pump 4. Controller 45 First temperature sensor 46 Second temperature sensor 6 Battery temperature adjustment circuit 60 Secondary battery 61 Pump 62 Temperature Sensor 63 Chiller 7 Circuit switching valve 81 Chiller

Claims

[Claim 1] a heating circuit in which a heat medium supplied to the heater core is circulated; a battery temperature adjustment circuit in which a heat medium supplied to the secondary battery is circulated; a circuit switching valve that switches a connection state between the heating circuit and the battery temperature adjustment circuit; a sensor for measuring a temperature of the heat medium passing through the heater core; and a controller that controls the circuit switching valve based on a temperature measured by the sensor so as to supply a mixed heat medium obtained by mixing the heat medium that has passed through the heater core and the heat medium that has passed through the secondary battery to the secondary battery. Heat transfer medium circulation device for vehicles.

Images