Method for controlling electric vehicle, and electric vehicle system

Abstract

Provided is a method for controlling an electric vehicle comprising: a cooling water passage through which a cooling water flows; a battery disposed on the cooling water passage; an air conditioning device for adjusting the temperature inside the vehicle cabin; and a heat exchanger capable of exchanging heat between the vehicle cabin and the cooling water. This method for controlling the electric vehicle, when charging the battery, includes supplying vehicle cabin air and the cooling water to the heat exchanger to allow heat exchange between the vehicle cabin air and the cooling water, in a case where: the air conditioning device is stopped; no occupant is present in the vehicle cabin; the temperature of the cooling water at an inlet of the heat exchanger is lower than the temperature of the vehicle cabin air; and the charge increase amount, which increases due to the temperature rise of the battery caused by the heat exchange between the vehicle cabin and the cooling water, is larger than the reheating required power, which is a power required to raise, to a temperature before the heat exchange, the inside vehicle-cabin temperature which decreases due to the heat exchange.

Description

Electric vehicle control method and electric vehicle system

[0001] The present invention relates to a control method for an electric vehicle and an electric vehicle system.

[0002] The charging performance of a vehicle battery is highly dependent on the battery temperature, and as the battery temperature drops, the charging performance drops exponentially. Therefore, in order to improve the charging performance of the battery at low temperatures, it is necessary to improve the warm-up performance of the battery.

[0003] JP4228086B1 discloses an electric vehicle that controls the temperature of a battery during charging so that the battery temperature is maintained at a temperature that provides good charging efficiency (optimum charging temperature). In this electric vehicle, a heating device such as a heater is used to warm up the battery.

[0004] In the electric vehicle described in JP4228086B1, a heating device such as a heater is operated to warm up the battery so that the battery reaches an optimum temperature for charging, which may result in a deterioration in power efficiency.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a control method for an electric vehicle and an electric vehicle system that improves the warm-up performance of a battery while suppressing deterioration in electricity consumption.

[0006] According to one aspect of the present invention, there is provided a method for controlling an electric vehicle including a cooling water passage through which a cooling water flows, a battery arranged in the cooling water passage, an air conditioner for adjusting the temperature in the vehicle cabin, and a heat exchanger capable of exchanging heat between the heat in the vehicle cabin and the heat of the cooling water. In this control method for an electric vehicle, when charging the battery, if the air conditioner is stopped, there is no occupant in the vehicle cabin, the temperature of the cooling water at the inlet of the heat exchanger is lower than the temperature of the air in the vehicle cabin, and the charge increase amount caused by the increase in temperature of the battery due to the heat exchange between the heat in the vehicle cabin and the heat of the cooling water is greater than the re-heating required power that is the power required to raise the interior temperature lowered by the heat exchange to the temperature before the heat exchange, the air in the vehicle cabin and the cooling water are supplied to the heat exchanger to cause heat exchange between the air in the vehicle cabin and the cooling water.

[0007] Fig. 1 is a schematic configuration diagram of an electric vehicle system according to one embodiment. Fig. 2 is a side view of the electric vehicle at a connection portion between an air conditioning unit and a vehicle interior. Fig. 3 is a block diagram showing the flow of air and coolant in battery temperature regulation control during normal operation. Fig. 4 is a block diagram showing the flow of air and coolant in battery warm-up control during charging. Fig. 5 is a control block diagram of battery warm-up control during charging. Fig. 6 is a flowchart of battery warm-up control during charging.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] 1 is a schematic diagram of an electric vehicle system 100 according to one embodiment. The electric vehicle system 100 is an electric vehicle system mounted on an electric vehicle to which a control method according to one embodiment of the present invention is applied, and is a temperature control system that controls the temperature of a battery mounted on the electric vehicle. The electric vehicle here may be, for example, a hybrid vehicle or an electric vehicle.

[0010] 1, the electric vehicle system 100 includes a cooling water passage 1 through which cooling water flows, an air conditioning circuit 2 through which air conditioning refrigerant (air) flows, and a controller 50. A battery pack (battery) 10, a heater 11, a heater core 21, a water-cooled condenser (condenser) 22, a chiller 23, an electric powertrain (ePT) unit 30, and a radiator 40 are arranged on the cooling water passage 1, and an air conditioning unit 20, a water-cooled condenser (condenser) 22, and a chiller 23 are arranged on the air conditioning circuit 2.

[0011] The cooling water passage 1 is a cooling water circuit through which cooling water flows to warm up or cool the battery in the battery pack 10. The cooling water passage 1 includes first to third valves 61 to 63 that switch the circuit through which the cooling water flows and first to third pumps 71 to 73 that circulate the cooling water. The cooling water passage 1, the heater 11, the heater core 21, the water-cooled condenser 22, the chiller 23, the electric powertrain (ePT) unit 30, and the radiator 40 on the cooling water passage 1 constitute a battery water cooling device. A temperature sensor (not shown) that detects the temperature of the cooling water flowing through the cooling water passage 1 is provided in the cooling water passage 1 near the inlet of the battery pack 10. The detected temperature of the cooling water is transmitted to the controller 50.

[0012] The battery pack 10 is, for example, a lithium-ion battery, and includes multiple battery modules (not shown) each having multiple battery cells connected in series or in a combination of series and parallel. The multiple battery modules are connected in parallel or series to form a high-output, large-capacity battery. The battery formed by the multiple battery modules supplies power to an electric powertrain (ePT) unit 30 for driving a motor.

[0013] The battery pack 10 is provided on the cooling water passage 1, and as will be described later, heated or cooled cooling water in the cooling water passage 1 is supplied to the battery pack 10. This heats or cools the battery of the battery pack 10 (hereinafter also referred to as "battery 10"). The battery 10 is configured to be chargeable by an external charger. The battery pack 10 is also provided with a temperature sensor (not shown) that detects the temperature of the battery 10. The detected temperature of the battery 10 is transmitted to the controller 50.

[0014] The heater 11 is disposed on the cooling water passage 1 downstream of the battery pack 10. The heater 11 heats the cooling water discharged from the battery pack 10. The heated cooling water circulates within the cooling water passage 1 and is supplied to the battery pack 10. The operation of the heater 11 is controlled by a controller 50, which activates the heater 11 when it is necessary to raise the temperature of the battery 10.

[0015] The air conditioning device is made up of an air conditioning unit 20, a heater core 21, a water-cooled condenser (condenser) 22, and a chiller 23. The air conditioning unit 20 is disposed on an air conditioning circuit 2 through which a refrigerant (air) circulates, and the heater core 21 is disposed on a cooling water passage 1. The water-cooled condenser (condenser) 22 and the chiller 23 are disposed on the air conditioning circuit 2 and also on the cooling water passage 1.

[0016] The air conditioning unit 20 is disposed on the air conditioning circuit 2 and includes a compressor, an evaporator, an expansion valve, a blower 201 ( FIG. 2 ), and other components (not shown). In the air conditioning unit 20, the refrigerant (air) flowing through the air conditioning circuit 2 is compressed by the compressor. The compressed refrigerant is supplied to the water-cooled condenser 22, where it exchanges heat with the cooling water flowing through the cooling water passage 1, as described below. In the air conditioning unit 20, the expansion valve rapidly expands the refrigerant that has exchanged heat with the cooling water in the water-cooled condenser 22, reducing the temperature and pressure of the refrigerant and supplying it to the evaporator and chiller 23. The evaporator evaporates the refrigerant (air) flowing through the air conditioning circuit 2 and supplies the evaporated refrigerant to the compressor.

[0017] FIG. 2 is a diagram showing the connection portion between the air conditioning unit 20 and the vehicle interior 80, and is a side view of an electric vehicle on which the electric vehicle system 100 is installed.

[0018] As shown in FIG. 2 , the air conditioning unit 20 is connected to the passenger compartment 80 via an air pipe 90. A blower 201 of the air conditioning unit 20 supplies air whose temperature has been adjusted in the air conditioning circuit 2 into the passenger compartment 80 via the air pipe 90. The blower 201 is configured to perform outside air circulation, which involves taking outside air into the air conditioning device and discharging the air inside the passenger compartment 80 to the outside. The operation of the air conditioning unit 20 (blower 201, compressor, expansion valve, etc.) is controlled by a controller 50. When the air conditioning device is off, the air conditioning unit 20 normally does not operate. The passenger compartment 80 is provided with a temperature sensor that detects the temperature of the air in the passenger compartment 80 and a load sensor that detects the load on each seat. Information on the detected air temperature inside the passenger compartment 80 and the detected load on each seat is transmitted to the controller 50.

[0019] The heater core 21, the water-cooled condenser 22, and the chiller 23 are arranged in parallel with one another on the cooling water passage 1. These can also be arranged in a series circuit by switching the first and second valves 61, 62 or by installing another valve.

[0020] The heater core 21 is a heat exchanger provided in the air conditioning system. The heater core 21 is provided on the cooling water passage 1 downstream of the heater 11 and on the air piping 90 between the air conditioning unit 20 and the passenger compartment 80. That is, the cooling water passage 1 and the air piping 90 each pass through the heater core 21. Air is introduced into the air piping 90 passing through the heater core 21 by a blower 201, and heat is exchanged between the air introduced into the heater core 21 and the coolant in the cooling water passage 1. The air that has exchanged heat with the coolant by the heater core 21 is introduced into the passenger compartment 80, heating or cooling the passenger compartment 80. A temperature sensor (not shown) is provided in the cooling water passage 1 near the inlet of the heater core 21 to detect the water temperature at the inlet of the heater core 21. The inlet water temperature of the heater core 21 detected by the temperature sensor is sent to the controller 50. Also, although not shown, the air piping 90 between the air conditioning unit 20 and the vehicle interior 80 has a path that passes through the heater core 21 and a path that bypasses the heater core 21, and the blower 201 includes a blower that introduces air into the path that passes through the heater core 21 and a blower that introduces air into the path that bypasses the heater core 21.

[0021] The water-cooled condenser 22 condenses and liquefies the refrigerant (air) compressed by the compressor of the air conditioning unit 20. The water-cooled condenser 22 is provided in parallel with the heater core 21 in the cooling water passage 1 upstream of the heater core 21, and is also disposed on the air conditioning circuit 2, and exchanges heat between the coolant flowing in the cooling water passage 1 and the refrigerant flowing in the air conditioning circuit 2.

[0022] The chiller 23 is provided in parallel with the heater core 21 and the water-cooled condenser 22 in the cooling water passage 1 upstream of the water-cooled condenser 22, and is also disposed on the air conditioning circuit 2. The chiller 23 exchanges heat between the refrigerant in the air conditioning circuit 2, which has been made low-temperature and low-pressure by the expansion valve, and the heat of the cooling water flowing through the cooling water passage 1.

[0023] The electric powertrain (ePT) unit 30 includes a DC-DC converter, an inverter, a traction motor, etc. The ePT unit 30 is arranged in parallel with and on the cooling water passage 1 downstream of the heater core 21, water-cooled condenser 22, and chiller 23 that make up the air conditioning system. Heat from the electric powertrain (ePT) unit 30 is discarded into the coolant flowing through the cooling water passage 1.

[0024] The radiator 40 is a cooling mechanism that exchanges heat between the coolant flowing through the cooling water passage 1 and the atmosphere, and is disposed in parallel with the ePT unit 30 in the cooling water passage 1 downstream of the ePT unit 30. A fan 41 for the radiator 40 is provided near the radiator 40, and operating the fan 41 can cool the coolant flowing through the cooling water passage 1. The radiator 40 is also disposed near a grille shutter 42 that introduces airflow into the vehicle, and when the grille shutter 42 is open, the airflow hits the radiator 40, thereby cooling the coolant in the cooling water passage 1. The operation of the fan 41 and the opening and closing of the grille shutter 42 are controlled by a controller 50.

[0025] The first to third valves 61 to 63 switch the cooling water flow circuit. The first valve 61 is a three-way valve provided in the cooling water passage 1 upstream of the chiller 23 and controls the flow rate of cooling water passing through the chiller 23. The second valve 62 is a three-way valve provided in the cooling water passage 1 upstream of the water-cooled condenser 22 and heater core 21 and controls the flow rate of cooling water passing through the water-cooled condenser 22 and heater core 21. When the second valve 62 is controlled so that cooling water flows only through the water-cooled condenser 22, the cooling water passage 1 is disconnected from the heater core 21 and ePT unit 30. In other words, the second valve 62 constitutes a switching device that connects or disconnects the cooling water passage 1 and the heater core 21. The third valve 63 is a three-way valve provided in the cooling water passage 1 between the radiator 40 and the ePT unit 30 and controls the flow rate of cooling water passing through the ePT unit 30. The opening degrees of the first to third valves 61 to 63 are controlled by a controller 50 .

[0026] The first to third pumps 71 to 73 are water pumps that circulate the cooling water flowing through the cooling water passage 1. The first pump 71 is provided in the cooling water passage 1 between the heater 11 and the first valve 61, and controls the flow rate of the cooling water supplied to the first valve 61. The second pump 72 is provided in the cooling water passage 1 between the second valve 62 and the heater core 21, and controls the flow rate of the cooling water passing through the heater core 21 together with the second valve 62. The third pump 73 is provided in the cooling water passage 1 between the radiator 40 and the third valve 63, and controls the flow rate of the cooling water supplied to the third valve 63. The operations of the first to third pumps 71 to 73 are controlled by the controller 50.

[0027] The controller 50 is configured by a computer that includes a central processing unit (CPU), a read-only memory (ROM), a random access memory (RAM), and an input / output interface (I / O interface) and is programmed to be able to execute the processes described below. Note that the controller 50 can also be configured by multiple computer hardware that executes the processes in a distributed manner.

[0028] The controller 50 acquires the temperature of the battery 10, the temperature of the coolant in the cooling water passage 1 passing through the battery 10, the inlet water temperature of the heater core 21, the air temperature in the passenger compartment 80, and the load information of each seat in the passenger compartment 80. The controller 50 also acquires information on whether the air conditioning device is on or off (hereinafter referred to as air conditioning on / off information), and the set temperature of the air conditioning.

[0029] The controller 50 also performs temperature control of the battery 10. Specifically, it controls the operation of the heater 11 and the radiator 40 (the radiator fan 41 and the grille shutter 42), and also controls the operation of the first to third valves 61 to 63 and the first to third pumps 71 to 73 to switch the pattern of the coolant circuit through which the coolant flows in the cooling water passage 1. In this way, the controller 50 controls the temperature of the coolant in the cooling water passage 1 that passes through the battery 10, thereby controlling the temperature of the battery 10 (hereinafter referred to as battery temperature control during normal operation). Furthermore, when the battery 10 is charged by an external charger or the like, the controller 50 performs warm-up control of the battery 10 during charging, which will be described later.

[0030] In the electric vehicle system 100 configured as described above, the coolant in the cooling water passage 1 is heated or cooled by waste heat from the heater 11 and the ePT unit 30, and heat exchange by the heater core 21, the water-cooled condenser 22, and the chiller 23. The heated or cooled coolant passes through the battery 10, thereby controlling the temperature of the battery 10.

[0031] The charging performance of a vehicle battery is highly dependent on the battery temperature, and as the battery temperature drops, the charging performance declines exponentially. Therefore, it is necessary to improve the warm-up performance of the battery during charging. However, when a heating device (e.g., the heater 11 in the electric vehicle system 100 of this embodiment) is used to warm up the battery during charging, the operation of the heating device to warm up the battery may result in a deterioration in power consumption.

[0032] Therefore, in this embodiment, when charging the battery 10, if certain requirements are met, the air and coolant in the vehicle compartment 80 are supplied to the heater core 21 (heat exchanger) to perform heat exchange between the air and coolant in the vehicle compartment 80. Specifically, when the air conditioning system (air conditioning unit 20, heater core 21, water-cooled condenser 22, and chiller 23) is stopped, there is no passenger in the vehicle compartment 80, the temperature of the coolant at the inlet of the heater core 21 (heat exchanger) is lower than the temperature of the air in the vehicle compartment 80, and the charge increase amount caused by the temperature rise of the battery 10 due to the heat exchange between the heat in the vehicle compartment 80 and the heat of the coolant is greater than the power required to raise the temperature in the vehicle compartment 80, which is lowered by the heat exchange, to the temperature before the heat exchange (hereinafter referred to as the required re-heating power), the heater core 21 (heat exchanger) performs heat exchange between the air and coolant in the vehicle compartment 80. As a result, when charging the battery 10, heat stored in the air in the vehicle compartment 80 is transferred to the coolant, accelerating the warm-up of the battery 10. That is, because the warm-up performance of the battery 10 is improved, the temperature of the battery 10 rises quickly, and the charge amount can be increased. Furthermore, because the battery 10 can be warmed up using the heat in the vehicle compartment 80, deterioration in power consumption is suppressed compared to when the battery 10 is warmed up using only the heater (heating device) 11. Therefore, the warm-up performance of the battery 10 can be improved and the charge amount can be increased while suppressing deterioration in power consumption.

[0033] The warm-up control of the battery 10 during charging will be described in detail below.

[0034] 3 and 4 are system configuration diagrams of the electric vehicle system 100. Fig. 3 is a block diagram showing the flow of air and coolant in battery temperature regulation control during normal operation, and Fig. 4 is a block diagram showing the flow of air and coolant when predetermined requirements are met during warm-up control of the battery 10 during charging. Note that normal operation refers to a state in which the electric vehicle system 100 is activated and when warm-up control of the battery 10 during charging is not being executed.

[0035] As shown in FIGS. 3 and 4 , the electric vehicle system 100 includes an air conditioning system 101 including an air conditioning device B1, a heat exchanger B2, and a vehicle interior 80, a battery water cooling system 102 including the heat exchanger B2, a battery water cooling device B3, and a secondary battery B4, a detection device B5 including various sensors, and a controller 50 including a calculation device B6 and a storage device B7.

[0036] The air conditioning system 101 is composed of an air conditioning circuit 2, an air conditioning device B1 composed of an air conditioning unit 20, a water-cooled condenser 22, a chiller 23, etc. on the air conditioning circuit 2, a heat exchanger B2 composed of a heater core 21, and a vehicle interior 80. For convenience, in Figures 3 and 4, the heat exchanger B2 composed of the heater core 21 is shown as being separate from the air conditioning device B1, but in reality, the heater core 21 constitutes part of the air conditioning device.

[0037] The battery water cooling system 102 is composed of a heat exchanger B2 consisting of a heater core 21, a cooling water passage 1, a battery water cooling device B3 consisting of a heater 11 on the cooling water passage 1, a water-cooled condenser 22, a chiller 23, an electric powertrain (ePT) unit 30, a radiator 40, etc., and a secondary battery B4 consisting of a battery 10. Note that in Figures 3 and 4, for convenience, the heat exchanger B2 consisting of the heater core 21 is configured separately from the battery water cooling device B3, but in reality, the heater core 21 constitutes part of the battery water cooling device. In other words, the heater core 21 is part of the air conditioning system and part of the battery water cooling device.

[0038] The detection device B5 is a variety of sensors, and includes a temperature detection unit B51 and a load detection unit B52. The temperature detection unit B51 detects the temperature of the battery 10, the temperature of the coolant in the cooling water passage 1 passing through the battery 10, the inlet water temperature of the heater core 21, the air temperature in the passenger compartment 80, etc., and transmits the detected values ​​to the controller 50. The load detection unit B52 detects the load on each seat in the passenger compartment 80 and transmits the detected values ​​to the controller 50 as load information.

[0039] The controller 50 is composed of a calculation device B6 that acquires various detected temperature information and load information from the detection device B5 and executes various processes, and a storage device B7 that stores programs for executing the processes. The controller 50 (calculation device B6) normally controls the air conditioner B1 so that the temperature inside the vehicle compartment 80 is maintained at a desired temperature based on the air temperature inside the vehicle compartment 80 and the set temperature of the air conditioner. The controller 50 (calculation device B6) also normally controls the battery water cooling device B3 so that the temperature of the battery 10 is maintained at an appropriate temperature based on the temperature of the battery 10, the temperature of the coolant in the cooling water passage 1 that flows through the battery 10, the inlet water temperature of the heater core 21, the air temperature inside the vehicle compartment 80, and the like. When charging the battery 10, the controller 50 (calculation device B6) executes warm-up control of the battery 10 during charging, which involves heat exchange between the air inside the vehicle compartment 80 and the coolant, if predetermined requirements are met.

[0040] 3, when the air conditioner B1 is set to ON, outside air is taken into the air conditioner B1, and the air heated or cooled by the air conditioner B1 is supplied to the passenger compartment 80 via the heat exchanger B2. In this way, the passenger compartment 80 is cooled or heated.

[0041] The heated or cooled air taken into the passenger compartment 80 cools or heats the passenger compartment 80 and is then discharged to the outside through an outlet (not shown) in the passenger compartment 80. In this way, under normal circumstances, outside air is introduced into the air conditioning device B1, and the cooled or heated air is discharged from the passenger compartment 80 to the outside air.

[0042] Furthermore, under normal circumstances, the coolant in the cooling water passage 1 circulates through the secondary battery B4 (battery 10), the battery water cooling device B3, and the heat exchanger B2 (heater core 21). The temperature of the coolant is controlled by the battery water cooling device B3 and the heat exchanger B2 (heater core 21), thereby controlling the temperature of the battery 10. When heat exchange between the air in the passenger compartment 80 and the coolant is not required based on the air temperature in the passenger compartment 80, the set temperature of the air conditioning, the temperature of the coolant, etc., the coolant in the cooling water passage 1 is controlled to circulate between the secondary battery B4 (battery 10) and the battery water cooling device B3 without passing through the heat exchanger B2 (heater core 21).

[0043] On the other hand, when warm-up control of the battery 10 is executed during charging, if predetermined requirements are satisfied, as shown in FIG. 4 , air in the vehicle compartment 80 is supplied to the air conditioner B1 via the heat exchanger B2 (heater core 21), and the air supplied to the air conditioner B1 is supplied back into the vehicle compartment 80 without passing through the heat exchanger B2 (heater core 21). That is, when predetermined requirements are satisfied during warm-up control of the battery 10 during charging, air is circulated between the vehicle compartment 80 and the air conditioner B1. This prevents the air in the vehicle compartment 80 from being cooled by outside air, so that the heat of the air in the vehicle compartment 80 can be efficiently used to warm up the battery 10. Ideally, when predetermined requirements are satisfied during warm-up control of the battery 10 during charging, outside air should not be drawn into the vehicle compartment 80 at all. However, in reality, a certain amount of outside air enters the vehicle compartment 80 due to the structure of an exhaust port or the like in the vehicle compartment 80.

[0044] Furthermore, even when predetermined requirements are met in the warm-up control of the battery 10 during charging, the coolant in the cooling water passage 1 circulates through the secondary battery B4 (battery 10), the battery water cooling device B3, and the heat exchanger B2 (heater core 21). This allows heat exchange between the air in the vehicle compartment 80 and the coolant by the heat exchanger B2 (heater core 21). This allows the heat in the vehicle compartment 80 to be used to warm up the battery 10 when charging. This reduces the deterioration of power consumption compared to warming up the battery 10 using only the heater (heating device) 11. In other words, the warm-up performance of the battery 10 can be improved while reducing the deterioration of power consumption. If the heat exchange between the air in the vehicle compartment 80 and the coolant alone is not enough to warm up the battery 10 to the optimum charging temperature, the heater 11 included in the battery water cooling device B3 further heats the coolant to raise the temperature of the battery 10 to the optimum charging temperature.

[0045] Here, in the warm-up control of the battery 10 during charging, the predetermined conditions for performing heat exchange between the air in the passenger compartment 80 and the coolant by the heat exchanger B2 (heater core 21) are specifically that the air conditioning system (air conditioning unit 20, heater core 21, water-cooled condenser 22, and chiller 23) is stopped, there are no occupants in the passenger compartment 80, the temperature of the coolant at the inlet of the heater core 21 (heat exchanger) is lower than the temperature of the air in the passenger compartment 80, and the increase in charge due to the temperature rise of the battery 10 caused by the heat exchange between the heat in the passenger compartment 80 and the heat of the coolant is greater than the power required for reheating. When charging the battery 10, if all of these conditions are met, the heater core 21 (heat exchanger) performs heat exchange between the air in the passenger compartment 80 and the coolant.

[0046] When the air conditioning system is stopped, there is no demand for heating or cooling the vehicle interior 80, and therefore the heat in the vehicle interior 80 is used to warm up the battery 10 during charging, so that even if the temperature in the vehicle interior 80 drops, there is no risk of the driver or other occupants (hereinafter referred to as the driver, etc.) feeling uncomfortable or uneasy. On the other hand, when the air conditioning system is on (operating), there is a demand for heating or cooling by the driver, etc., so if the temperature in the vehicle interior 80 drops, there is a risk of the driver, etc. feeling uncomfortable or uneasy. Therefore, only when the air conditioning system is stopped, the heater core 21 exchanges heat between the air in the vehicle interior 80 and the coolant.

[0047] Furthermore, when there is no occupant in the passenger compartment 80, the heat in the passenger compartment 80 is used to warm up the battery 10 during charging, so that even if the temperature in the passenger compartment 80 drops, there is no risk of the driver or other persons feeling uncomfortable or uneasy. On the other hand, if there is an occupant in the passenger compartment 80 and the temperature in the passenger compartment 80 drops suddenly, there is a risk of the driver or other persons feeling uncomfortable or uneasy. Therefore, only when there is no occupant in the passenger compartment 80, the heater core 21 exchanges heat between the air in the passenger compartment 80 and the coolant. The presence or absence of an occupant in the passenger compartment 80 is determined based on information (load information) indicating whether or not a load is detected on each seat.

[0048] Furthermore, when the temperature of the coolant at the inlet of the heater core 21 (heat exchanger) (hereinafter referred to as the inlet water temperature of the heater core 21) is lower than the temperature of the air in the vehicle compartment 80, the coolant in the heater core 21 absorbs heat from the air in the air piping 90, causing the coolant temperature to rise and warming up the battery 10. On the other hand, when the inlet water temperature of the heater core 21 is equal to or higher than the temperature of the air in the vehicle compartment 80, the coolant in the heater core 21 dissipates heat to the air in the air piping 90, or the coolant does not absorb heat from the air in the air piping 90. In this case, the battery 10 is cooled or not warmed up by heat exchange in the heater core 21 (heat exchanger). Therefore, only when the inlet water temperature of the heater core 21 is lower than the temperature of the air in the vehicle compartment 80, does the heater core 21 exchange heat between the coolant and the air in the vehicle compartment 80.

[0049] Furthermore, if the charge increment caused by the temperature rise of the battery 10 due to heat exchange between the heat in the vehicle interior 80 and the coolant is greater than the required power for reheating, heat exchange between the air in the vehicle interior 80 and the coolant can suppress deterioration in power consumption. On the other hand, if the charge increment caused by the temperature rise of the battery 10 due to heat exchange between the heat in the vehicle interior 80 and the coolant is less than the required power for reheating, even if the battery 10 is warmed up by heat exchange, power greater than the charge increment is used to raise the temperature in the vehicle interior 80, which has been reduced by the heat exchange, to the temperature before the heat exchange. Therefore, deterioration in power consumption cannot be suppressed, or may even worsen. Therefore, heat exchange between the air in the vehicle interior 80 and the coolant by the heater core 21 is performed only when the charge increment caused by the temperature rise of the battery 10 due to heat exchange between the heat in the vehicle interior 80 and the coolant is greater than the required power for reheating.

[0050] The charge increase amount due to the temperature rise of the battery 10 caused by heat exchange between the heat in the vehicle compartment 80 and the heat of the coolant is calculated from the difference between the charge amount when charging with heat exchange performed by the heater core 21 and the charge amount when charging without heat exchange. More specifically, the charge amount when charging with heat exchange is calculated by predicting a first battery temperature transition, which is the temperature transition of the battery 10 when charging with heat exchange performed by the heater core 21, and calculating the charge amount based on the output of a charger connected to the battery 10 and the first battery temperature transition. The first battery temperature transition is calculated based on the temperature of the battery 10 at the start of charging, the battery warm-up efficiency of the electric vehicle system (battery temperature control system) 100, and the amount of heat recovered by the heater core 21 from the air in the vehicle compartment 80. The charge amount when charging without heat exchange is calculated by predicting a second battery temperature transition, which is the temperature transition of the battery 10 when charging without heat exchange by the heater core 21, and calculating the charge amount based on the output of a charger connected to the battery 10 and the second battery temperature transition. The second battery temperature transition is calculated based on the temperature of the battery 10 at the start of charging and the battery warm-up efficiency of the electric vehicle system (battery temperature regulation system) 100 .

[0051] The required power for reheating is calculated based on the outside air temperature, the air conditioning temperature setting before charging, the capacity of the passenger compartment 80, and the heating efficiency. The outside air temperature can be obtained by a temperature sensor outside the vehicle, but is not limited to this.

[0052] FIG. 5 is a control block diagram of the warm-up control of the battery during charging.

[0053] As shown in FIG. 5, a comparator B101 compares the inlet water temperature of the heater core 21 with the air temperature in the passenger compartment 80, and the comparison result is input to a determination unit B115.

[0054] Furthermore, a heat recovery amount calculator B102 calculates the transition of the heat recovery amount of the coolant (hereinafter also referred to as the heat recovery amount) when heat is exchanged between the coolant and the air in the passenger compartment 80, based on the inlet water temperature of the heater core 21 and the air temperature in the passenger compartment 80. The heat recovery amount is calculated, for example, by referring to a map of the difference between the air temperature in the passenger compartment 80 and the inlet water temperature of the heater core 21, which has been obtained in advance by an experiment or the like, and the heat recovery amount.

[0055] Next, in adder B103, the calculated change in the heat recovery amount is added to the change in the amount of heat supplied to battery 10 based on the battery warm-up efficiency of electric vehicle system (battery temperature control system) 100 (hereinafter also referred to as the amount of heat supplied by the system warm-up function).

[0056] Next, the first battery temperature transition prediction unit B104 predicts the first battery temperature transition, which is the transition of the temperature of the battery 10 when charging by performing heat exchange using the heater core 21, from the temperature of the battery 10 at the start of charging and the sum of the heat recovery amount and the heat supply amount by the system heating function.

[0057] Next, in the first charge amount calculation unit B105, the first charge amount, which is the charge amount of the battery 10 when charging by performing heat exchange using the heater core 21, is calculated from the first battery temperature trend and the output of the charger connected to the battery 10.

[0058] On the other hand, the second battery temperature transition prediction unit B106 predicts the second battery temperature transition, which is the transition of the temperature of the battery 10 when charging is performed without performing heat exchange by the heater core 21, based on the temperature of the battery 10 at the start of charging and the amount of heat supplied by the system heating function.

[0059] In addition, the second charge amount calculation unit B107 calculates the second charge amount, which is the charge amount of the battery 10 when charging without performing heat exchange by the heater core 21, from the second battery temperature trend and the output of the charger connected to the battery 10.

[0060] Next, a subtractor B108 calculates the difference between the first charge amount and the second charge amount, and the calculation result is input to a comparator B112 as the increase in the amount of power to be charged (hereinafter also referred to as the charge increase amount) that increases due to the temperature rise of the battery 10 caused by heat exchange between the heat inside the passenger compartment 80 and the heat of the coolant.

[0061] As shown in FIG. 5, a subtractor B109 calculates the difference between the air conditioning set temperature before charging and the outside air temperature, and the calculation result is input to a reheating required heat amount calculation unit B110 as the temperature to be raised to after charging.

[0062] Next, a reheating heat quantity calculation unit B110 calculates the heat quantity required to raise the temperature of the battery 10 to the pre-charge air conditioning set temperature (hereinafter also referred to as reheating heat quantity) after charging is completed, based on the difference between the pre-charge air conditioning set temperature and the outside air temperature and the capacity of the vehicle interior 80. The reheating heat quantity is calculated using, but is not limited to, a map of the temperature to be raised, the capacity of the vehicle interior 80, and the required heat quantity. The outside air temperature is used to calculate the temperature to be raised to after charging because it is unlikely that the temperature inside the vehicle interior 80 will be lower than the outside air temperature when charging is completed.

[0063] Next, in a divider B111, the heat quantity required for reheating is divided by the heating efficiency (for example, the heat quantity required to raise the temperature inside the passenger compartment 80 by 1°C), and the calculation result is input to a comparator B112 as the required power for reheating.

[0064] The comparator B112 compares the amount of charge increase with the amount of power required for reheating, and the comparison result is input to the determination unit B115.

[0065] 5, a determination unit B113 determines whether the air conditioner is on or off. The result of the determination whether the air conditioner is on or off is input to a determination unit B115.

[0066] 5, the comparison unit B114 determines whether the load detected on each seat exceeds a predetermined threshold. The threshold is set to a value that allows the user to recognize that a person is seated. The comparison result of the comparison unit B114 is input to the determination unit B115.

[0067] The determination unit B115 determines whether to perform heat exchange between the air in the passenger compartment 80 and the coolant in the heater core 21. If the inlet water temperature of the heater core 21 is lower than the air temperature in the passenger compartment 80, the charge increase is greater than the reheating power required, the air conditioning system is off (stopped), and no load exceeding a predetermined threshold is detected on the seat in the passenger compartment 80, the determination unit B115 determines to perform heat exchange in the heater core 21. If it is determined to perform heat exchange in the heater core 21, the coolant passage 1 and the heater core 21 are connected, and the air in the passenger compartment 80 and the coolant are supplied to the heater core 21. On the other hand, if the inlet water temperature of the heater core 21 is equal to or higher than the air temperature in the passenger compartment 80, or if the charge increase is equal to or less than the reheating power required, or if the air conditioning system is on (operating), or if a load exceeding a predetermined threshold is detected on the seat in the passenger compartment 80, the determination unit B115 determines not to perform heat exchange in the heater core 21, and the heater core 21 and the coolant passage 1 are disconnected.

[0068] 6 is a flowchart of the warm-up control of the battery during charging. The following controls are all repeatedly executed by the controller 50 while the battery 10 is being charged. The controller 50 also acquires detected values ​​from various sensors as needed.

[0069] When the battery 10 is connected to an external charger, the controller 50 starts warming up the battery during charging.

[0070] In step S101, the controller 50 determines whether the air conditioner is off (stopped). If the air conditioner is on (operating), the controller 50 ends the battery warm-up control during charging and executes the battery temperature control during normal operation. On the other hand, if the air conditioner is off (stopped), the controller 50 executes the process of step S102.

[0071] In step S102, the controller 50 determines whether or not there is an occupant in the passenger compartment 80. The presence or absence of an occupant is determined based on whether or not the load detected on each seat in the passenger compartment 80 exceeds a predetermined threshold. If a load exceeding the predetermined threshold is detected on a seat in the passenger compartment 80, the controller 50 determines that there is an occupant in the passenger compartment 80 and terminates the warm-up control of the battery during charging. On the other hand, if a load exceeding the predetermined threshold is not detected on a seat in the passenger compartment 80, the controller 50 determines that there is no occupant in the passenger compartment 80 and executes the process of step S103.

[0072] In step S103, the controller 50 determines whether the inlet water temperature (coolant temperature) of the heater core 21 is lower than the air temperature in the vehicle compartment 80. If the inlet water temperature of the heater core 21 is equal to or higher than the air temperature in the vehicle compartment 80, the controller 50 ends the warm-up control of the battery during charging. On the other hand, if the inlet water temperature of the heater core 21 is lower than the air temperature in the vehicle compartment 80, the controller 50 executes the process of step S104.

[0073] In step S104, the controller 50 determines whether the charge increment is greater than the reheating power required. If the charge increment is equal to or less than the reheating power required, the controller 50 ends the battery warm-up control during charging. On the other hand, if the charge increment is greater than the reheating power required, the controller 50 executes the process of step S105.

[0074] In step S105, the controller 50 connects the cooling water passage 1 to the heater core 21 and supplies the cooling water and the air in the passenger compartment 80 to the heater core 21. This causes heat exchange between the air in the passenger compartment 80 and the cooling water.

[0075] As described above, in the electric vehicle system 100, when the air conditioning system is stopped, there is no passenger in the passenger compartment 80, the inlet water temperature of the heater core 21 is lower than the air temperature in the passenger compartment 80, and the charging increase is greater than the required power for reheating, the heater core 21 (heat exchanger) is controlled to perform heat exchange between the air and the coolant in the passenger compartment 80. This allows the battery 10 to be warmed up by utilizing the heat in the passenger compartment 80 when charging the battery 10.

[0076] According to the control method for an electric vehicle of the above embodiment, the following effects can be obtained.

[0077] According to the control method for an electric vehicle of this embodiment, when charging the battery 10, if the air conditioning system is stopped, there is no passenger in the vehicle cabin, the temperature of the coolant at the inlet of the heater core 21 (heat exchanger) is lower than the temperature of the air in the vehicle cabin 80, and the charge increase due to the temperature rise of the battery 10 caused by heat exchange between the heat in the vehicle cabin 80 and the heat of the coolant is greater than the power required to raise the temperature in the vehicle cabin 80 to the temperature before the heat exchange, the air in the vehicle cabin 80 and the coolant are supplied to the heater core 21 (heat exchanger) to exchange heat between the air in the vehicle cabin 80 and the coolant. This transfers heat stored in the air in the vehicle cabin 80 to the coolant when charging the battery 10, thereby facilitating warm-up of the battery 10. In other words, the warm-up performance of the battery 10 is improved, so the temperature of the battery 10 rises more quickly and the charge amount can be increased. Furthermore, since the battery 10 can be warmed up by utilizing the heat in the vehicle interior 80, deterioration in power consumption is suppressed compared to when the battery 10 is warmed up using only the heater (heating device) 11. Therefore, the warm-up performance of the battery 10 can be improved and the charge amount can be increased while suppressing deterioration in power consumption.

[0078] According to the control method for an electric vehicle of this embodiment, heat is exchanged between the air in the vehicle compartment 80 and the coolant by the heater core 21 provided in the air conditioning system. In this way, the warm-up performance is improved using the existing configuration of the electric vehicle system 100. Therefore, costs can be reduced compared to when the vehicle system is enhanced to improve the warm-up performance. In other words, the warm-up performance when charging the battery 10 can be improved without increasing costs.

[0079] According to the control method for an electric vehicle of this embodiment, when air in the passenger compartment 80 is supplied to the heater core 21, the air is circulated between the passenger compartment 80 and the air conditioning system. This prevents the air in the passenger compartment 80 from being cooled by outside air when charging the battery 10, so that the heat of the air in the passenger compartment 80 can be used efficiently to warm up the battery 10.

[0080] According to the control method for an electric vehicle of this embodiment, the presence or absence of an occupant in the passenger compartment 80 is determined based on whether a load exceeding a predetermined value (threshold value) is detected on each seat, and when the battery 10 is being charged, if there is an occupant in the passenger compartment 80, coolant is not supplied to the heater core 21 (heat exchanger). As a result, heat exchange between the air in the passenger compartment 80 and the coolant does not occur when there is an occupant in the passenger compartment 80, and therefore, a sudden drop in the temperature in the passenger compartment 80 due to heat exchange is prevented, which would cause discomfort or strangeness to the occupants, such as the driver.

[0081] According to the control method for an electric vehicle of this embodiment, the charge increase amount is calculated from the difference between the charge amount when charging is performed with heat exchange by the heater core 21 and the charge amount when charging is performed without heat exchange. That is, by performing heat exchange by the heater core 21, the battery 10 is heated (warmed up) by the heat generated in the vehicle cabin. In this case, the warm-up power consumption of the battery 10 increases, but the charge amount also increases. By determining the charge increase amount due to heat exchange in this way, it is possible to accurately compare the charge increase amount with the warm-up power consumption and the reheating power required due to the heat exchange, and to prevent control that results in a negative energy balance. This makes it possible to suppress deterioration of the battery 10 due to an increase in power consumption and the number of charge / discharge cycles.

[0082] According to the control method for an electric vehicle of this embodiment, a first battery temperature transition, which is a transition of the battery temperature when charging with heat exchange by the heater core 21, and a second battery temperature transition, which is a transition of the battery temperature when charging without heat exchange, are predicted. The charge amount when charging with heat exchange is calculated based on the output of a charger connected to the battery 10 and the first battery temperature transition, and the charge amount when charging without heat exchange is calculated based on the output of a charger connected to the battery 10 and the second battery temperature transition. Because the charge amount is calculated based on the first battery temperature transition, the second battery temperature transition, and the charger output, the charge amount can be more accurately determined. Therefore, the increase in warm-up power consumption and reheating power required due to heat exchange by the heater core 21 can be more accurately compared with the increase in charge amount, and control that results in a negative energy balance can be more effectively prevented. This can more effectively suppress deterioration of the electric fuel economy and deterioration of the battery 10 due to an increase in the number of charge / discharge cycles.

[0083] According to the control method for an electric vehicle of this embodiment, the first battery temperature transition is calculated based on the temperature of the battery 10 at the start of charging, the battery warm-up efficiency of the electric vehicle system (battery temperature control system) 100, and the amount of heat recovered by the heater core 21 (heat exchanger). The second battery temperature transition is calculated based on the temperature of the battery 10 at the start of charging and the battery warm-up efficiency of the electric vehicle system (battery temperature control system) 100. By calculating the first battery temperature transition and the second battery temperature transition in this manner, the charge amount can be more accurately determined, and control that results in a negative energy balance can be more effectively prevented. This makes it possible to more effectively suppress deterioration of the battery 10 due to an increase in the number of charge / discharge cycles.

[0084] According to the control method for an electric vehicle of this embodiment, the amount of heat recovered by the heater core 21 (heat exchanger) is calculated based on the temperature of the air in the passenger compartment 80 and the temperature of the coolant. By calculating the amount of heat recovered in this manner, the temperature transitions of the first battery and the second battery can be calculated, and the charge amount can be more accurately determined. Therefore, control that results in a negative energy balance can be more effectively prevented, and deterioration of the electric fuel economy and deterioration of the battery 10 due to an increase in the number of charge / discharge cycles can be more effectively suppressed.

[0085] According to the control method for an electric vehicle of this embodiment, the reheating power required is calculated based on the outside air temperature, the air conditioning temperature setting before charging, the capacity of the passenger compartment 60, and the heating efficiency. By knowing the reheating power required in this way, control that results in a negative energy balance is prevented. Therefore, it is possible to suppress deterioration of the battery 10 due to an increase in the number of charge / discharge cycles and deterioration of the battery 10.

[0086] In this embodiment, the heater core 21 is used to exchange heat between the air in the passenger compartment 80 and the coolant, but this is not limited to this, and a heat exchanger other than a heater core may be used as long as it exchanges heat between the air in the passenger compartment 80 and the coolant.

[0087] Furthermore, as in this embodiment, it is preferable that the heater core 21 is provided in the air conditioning system, but this is not necessarily limited to this, and the heater core 21 may be provided as a separate structure from the air conditioning system.

[0088] Furthermore, when air inside the passenger compartment 80 is supplied to the heater core 21 as in this embodiment, it is preferable to circulate the air between the passenger compartment 80 and the air conditioning unit, but this is not necessarily limited to this, and it is not necessary to circulate the air inside.

[0089] In addition, in this embodiment, the presence or absence of an occupant in the passenger compartment 80 is determined based on whether a load exceeding a predetermined value (threshold value) is detected on each seat, but this is not necessarily limited to this, and any method may be used as long as it can predict or detect the presence or absence of an occupant in the passenger compartment 80. For example, the presence or absence of an occupant may be detected by an infrared sensor in the passenger compartment 80.

[0090] The calculation method of the charge increase amount and the required re-heating power described in the present embodiment is merely an example and is not limited thereto. That is, the charge increase amount and the required re-heating power may be calculated using any known method.

[0091] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

Claims

1. A control method for an electric vehicle having a cooling water passage through which cooling water flows, a battery placed on the cooling water passage, an air conditioning unit that adjusts the temperature inside the vehicle cabin, and a heat exchanger that can exchange heat between the air inside the vehicle cabin and the heat of the cooling water, wherein, when charging the battery, if the air conditioning unit is stopped, there is no occupant in the vehicle cabin, the temperature of the cooling water at the inlet of the heat exchanger is lower than the temperature of the air inside the vehicle cabin, and the amount of charge increase caused by the temperature rise of the battery due to the heat exchange between the heat inside the vehicle cabin and the heat of the cooling water is greater than the required re-heating power that is the power required to raise the temperature inside the vehicle cabin that is lowered by the heat exchange to the temperature before the heat exchange, the air inside the vehicle cabin and the cooling water are supplied to the heat exchanger, thereby causing heat exchange between the air inside the vehicle cabin and the cooling water.

2. A control method for an electric vehicle as described in claim 1, wherein the heat exchanger is a heater core provided in the air conditioning device and configured to be able to exchange heat with the cooling water passage.

3. A control method for an electric vehicle according to claim 2, wherein when air in the vehicle compartment is supplied to the heater core, the air is circulated between the vehicle compartment and the air conditioning device.

4. A control method for an electric vehicle as claimed in claim 1 or 2, wherein the electric vehicle is equipped with a load sensor that detects the load on each seat, and the presence or absence of an occupant in the vehicle compartment is determined based on whether a load exceeding a predetermined value is detected on each seat.

5. A control method for an electric vehicle according to claim 1 or 2, wherein the increased charge amount is calculated from the difference between the charge amount when charging is performed with the heat exchange and the charge amount when charging is performed without the heat exchange.

6. A control method for an electric vehicle as claimed in claim 5, comprising: predicting a first battery temperature transition which is the transition of the battery temperature when charging after performing the heat exchange; predicting a second battery temperature transition which is the transition of the battery temperature when charging without performing the heat exchange; calculating the amount of charge when charging after performing the heat exchange based on the output of a charger connected to the battery and the first battery temperature transition; and calculating the amount of charge when charging without performing the heat exchange based on the output of a charger connected to the battery and the second battery temperature transition.

7. A control method for an electric vehicle as claimed in claim 6, wherein the electric vehicle is equipped with a heater that warms up the battery, the air conditioning device is equipped with a condenser arranged on the cooling water passage, the cooling water passage, the air conditioning device and the heater constitute a temperature control system that controls the temperature of the battery, the first battery temperature transition is calculated based on the temperature of the battery at the start of charging, the battery warm-up efficiency of the temperature control system and the amount of heat recovered by the heat exchanger, and the second battery temperature transition is calculated based on the temperature of the battery at the start of charging and the battery warm-up efficiency of the temperature control system.

8. A control method for an electric vehicle according to claim 7, wherein the amount of heat recovered by the heat exchanger is calculated based on the temperature of the air in the vehicle compartment and the temperature of the cooling water.

9. A control method for an electric vehicle according to claim 1 or 2, wherein the required reheating power is calculated based on the outside air temperature, the air conditioning temperature setting before charging, the vehicle interior capacity, and the heating efficiency.

10. An electric vehicle system comprising: a cooling water channel through which cooling water flows; a battery arranged on the cooling water channel; an air conditioning unit that adjusts the temperature inside the vehicle cabin; a heat exchanger that can exchange heat between heat inside the vehicle cabin and the heat of the cooling water; a switching device that connects or disconnects the cooling water channel and the heat exchanger; and a controller that controls the switching device, wherein, when charging the battery, if the air conditioning unit is stopped, there is no occupant in the vehicle cabin, the temperature of the cooling water at the inlet of the heat exchanger is lower than the temperature of the air inside the vehicle cabin, and an increase in charge amount due to a temperature rise in the battery caused by heat exchange between the heat inside the vehicle cabin and the heat of the cooling water is greater than a required re-heating power that is the power required to raise the temperature inside the vehicle cabin that is lowered by the heat exchange to the temperature before the heat exchange, the controller connects the cooling water channel and the heat exchanger to supply the cooling water to the heat exchanger and supplies the air inside the vehicle cabin to the heat exchanger to exchange heat between the air inside the vehicle cabin and the cooling water. Electric vehicle systems.

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