JP7848676B2 - Battery temperature control device - Google Patents

Description

This invention relates to a battery temperature control device for adjusting the temperature of a vehicle's traction battery.

Hybrid vehicles (HEVs) or electric vehicles (BEVs) are equipped with batteries for driving. Vehicles equipped with batteries also have a battery temperature control device that cools or heats the battery to maintain an appropriate temperature (for example, Patent Document 1).

Japanese Patent Publication No. 2020-013726

Incidentally, the battery temperature control system uses the battery's power to cool the coolant in a refrigeration cycle circuit, and then cools the battery with the coolant. Furthermore, the battery temperature control system uses the battery's power to heat the coolant with a heater, and then heats the battery to an appropriate temperature with the coolant. Therefore, even a slight reduction in the power consumption of the battery temperature control system can improve the vehicle's driving range.

Therefore, the present invention aims to provide a battery temperature control device that can reduce the power consumption of a battery.

The battery temperature control device according to the present invention is a battery temperature control device that uses the power of a vehicle's traction battery to cool or heat a heat transfer medium, thereby adjusting the battery temperature by cooling or heating the battery to an appropriate temperature using the heat transfer medium. It is characterized by having a first temperature range where the battery output is limited if the battery temperature falls outside that range, and a second temperature range where the upper limit temperature is lower and the lower limit temperature is higher than in the first temperature range. When the distance from the vehicle's current location to the destination is greater than a predetermined distance, the device adjusts the battery temperature so that it falls within the second temperature range. When the distance from the vehicle's current location to the destination is less than or equal to the predetermined distance, and the vehicle is parked for a predetermined time after arriving at the destination before the next drive, the device predicts the temperature change (the change in battery temperature over the predetermined time), determines a target temperature before the next drive (the target battery temperature before the next drive) within the first temperature range, calculates a target temperature before parking (the target battery temperature before parking) from the temperature change and the target temperature before the next drive, and adjusts the battery temperature with the minimum capacity necessary for the battery temperature to reach the target temperature before parking upon arrival at the destination.

By using the above configuration, battery power consumption can be reduced.

In the battery temperature control device according to the present invention, it is preferable that the control unit, when the temperature change is rising, determines the target temperature before the next drive to be within the range from the midpoint to the lower limit of the first temperature range.

By adopting the above configuration, battery power consumption can be further reduced.

In the battery temperature control device according to the present invention, it is preferable that the control unit, when the temperature change is decreasing, determines the target temperature before the next run to be within the range from the median value to the upper limit of the first temperature range.

By adopting the above configuration, battery power consumption can be further reduced.

In the battery temperature control device according to the present invention, if the calculated pre-parking target temperature is outside the first predetermined temperature range, it is preferable for the control unit to set the pre-parking target temperature to the closer of the upper or lower limit of the first temperature range.

By adopting the above configuration, it is possible to avoid the battery output being limited due to the pre-parking target temperature being set outside the first temperature range.

In the battery temperature control device according to the present invention, it is preferable that the control unit calculates the minimum capacity based on at least the distance from the current location to the destination, gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the current location to the destination.

According to the battery temperature control device of the present invention, the power consumption of the battery can be reduced.

This is a circuit diagram showing a battery temperature control device, which is one example of an embodiment. This is a block diagram showing the configuration of the control unit. This graph shows an example of battery temperature control at high ambient temperatures, illustrating the temperature control level, battery temperature, and time series. This graph shows an example of battery temperature control at low ambient temperatures, illustrating the temperature control level, battery temperature, and time series. This is a flowchart illustrating the flow of battery temperature control.

The following describes in detail an example of an embodiment of the present invention. In the following description, specific shapes, materials, directions, numerical values, etc., are illustrative examples to facilitate understanding of the present invention and can be appropriately modified according to the application, purpose, specifications, etc.

The battery temperature control device 10 is a device that adjusts the temperature of the traction battery 5 installed in the vehicle. As will be described in detail later, the battery temperature control device 10 can reduce the power consumption of the battery 5.

[vehicle]
The vehicle is a BEV that runs by driving a motor (not shown) solely with the power of the battery 5. However, the vehicle in this embodiment may also be a HEV that runs by driving both a gasoline engine and a motor.

[Battery]
The battery 5 includes a plurality of battery cells (single cells), and the battery cells are composed of, for example, lithium-ion secondary batteries, nickel-metal hydride secondary batteries, or all-solid-state batteries. The battery 5 is equipped with a battery temperature sensor 73 for detecting the battery temperature.

Here, if the temperature of battery 5 is too high or too low, the performance of battery 5 will deteriorate, leading to damage or accelerated degradation of the battery cells. Therefore, a first temperature range is set for battery 5, and if the temperature of battery 5 is outside this first temperature range, the output of battery 5 is limited. Furthermore, the battery temperature control device 10 typically adjusts the temperature of battery 5 so that it falls within a second temperature range, which has a lower upper temperature limit and a higher lower temperature limit than the first temperature range.

[Battery temperature control device]
The battery temperature control device 10 will be explained using Figures 1 to 4.

As shown in Figure 1, the battery temperature control device 10 uses the power of the battery 5 to cool or heat the cooling water, which acts as a heat transfer medium, and cools or heats the battery 5 to an appropriate temperature using the cooling water. The battery temperature control device 10 includes a low-temperature side cooling water circuit 20 for cooling the battery 5, a refrigeration cycle circuit 30 that absorbs heat from the low-temperature side cooling water circuit 20, a high-temperature side cooling water circuit 40 heated by the refrigeration cycle circuit 30, and an ECU (Electronic Control Unit) 50 as a control unit that controls each component of the battery temperature control device 10.

The low-temperature side cooling water circuit 20 is a circuit that cools the battery 5 by circulating low-temperature cooling water using the first low-temperature side water pump 21 and the second low-temperature side water pump 22, which then cools the battery 5 by the battery heat exchanger 23, absorbs heat into the refrigeration cycle circuit 30 by the chiller 24, and dissipates heat into the air by the low-temperature side radiator 25. The low-temperature side radiator 25 is capable of heat exchange with the high-temperature side radiator 44, which will be described later.

In the low-temperature side cooling water circuit 20, the battery heat exchanger 23, chiller 24, and low-temperature side radiator 25 are installed in parallel. The paths leading to the battery heat exchanger 23, the path from the first low-temperature side water pump 21, the path leading to the chiller 24, the path leading to the low-temperature side radiator 25, and the short-circuit path (a path for cooling other equipment) are switched and connected by a five-way valve 26.

The refrigeration cycle circuit 30 includes a compressor 31 for compressing the refrigerant, a water-cooled condenser 32 for heating the cooling water circulating in the high-temperature side cooling water circuit 40, an evaporator 33 for cooling the air supplied to the vehicle cabin, an evaporator-side expansion valve 34 for adjusting the amount of refrigerant circulated to the evaporator 33, a chiller 24 for absorbing heat from the cooling water circulating in the low-temperature side cooling water circuit 20, and a chiller-side expansion valve 36 for adjusting the amount of refrigerant circulated to the chiller 24. In the refrigeration cycle circuit 30, the evaporator 33 and the chiller 24 are connected in parallel. Furthermore, the discharge capacity (operating capacity) of the compressor 31 can be adjusted by adjusting the rotational speed of the electric motor.

The high-temperature side coolant circuit 40 is a circuit that cools the water-cooled condenser 32 by circulating high-temperature side coolant with a high-temperature side water pump 41, heats the heater core 43 which is heated by an electric heater 42 and heats the air supplied to the vehicle cabin, and cools the heater core 43 by dissipating heat into the air with a high-temperature side radiator 44. The high-temperature side radiator 44 is capable of heat exchange with the low-temperature side radiator 25 described above. The output of the electric heater 42 can be adjusted.

In the high-temperature side cooling water circuit 40, a water-cooled condenser 32, an electric heater 42, a heater core 43, and a high-temperature side radiator 44 are arranged in parallel. The paths leading to the water-cooled condenser 32 and electric heater 42, the path leading to the heater core 43, and the path leading to the high-temperature side radiator 44 are switched and connected by a three-way flow control valve 45.

As described above, the battery temperature control device 10 uses the power of the battery 5 to cool or heat the cooling water, and adjusts the temperature of the battery 5 by cooling or heating the battery 5 to an appropriate temperature using either the high-temperature or low-temperature cooling water.

In the battery temperature control device 10, when cooling the battery 5, the compressor 31 of the refrigeration cycle circuit 30 is driven, the chiller-side expansion valve 36 is adjusted, and refrigerant is circulated to the chiller 24, absorbing heat from the low-temperature side cooling water circuit 20. In the low-temperature side cooling water circuit 20, the second low-temperature side water pump 22 is driven, and the chiller 24 and the battery heat exchanger 23 are connected by a five-way valve 26, allowing the battery 5 to be cooled by the battery heat exchanger 23.

In the battery temperature control device 10, when heating the battery 5 to the appropriate temperature, the high-temperature side water pump 41 of the high-temperature side cooling water circuit 40 is driven, and the electric heater 42 is activated to heat the high-temperature side cooling water circuit 40, and the low-temperature side radiator 25 is heated by the high-temperature side radiator 44. In the low-temperature side cooling water circuit 20, the first low-temperature side water pump 21 and the second low-temperature side water pump 22 are driven, and the five-way valve 26 connects the second low-temperature side water pump 22 and the battery heat exchanger 23 to the low-temperature side radiator 25, so that the battery heat exchanger 23 heats the battery 5 to the appropriate temperature.

[Control unit (ECU)]
As described above, the ECU 50 controls each component of the battery temperature control device 10. The ECU 50 is a computer having a processor 51 with a CPU that performs information processing internally, and a memory 52 that stores software, programs, or data executed by the processor 51.

The ECU 50 is connected to the first low-temperature water pump 21, the second low-temperature water pump 22, and the five-way valve 26 of the low-temperature cooling water circuit 20; the compressor 31, the evaporator-side expansion valve 34, and the chiller-side expansion valve 36 of the refrigeration cycle circuit 30; the high-temperature water pump 41, the electric heater 42, and the three-way flow control valve 45 of the high-temperature cooling water circuit 40; the navigation device 71; and the battery temperature sensor 73. The ECU 50 is also configured to communicate with the information center 72.

The navigation device 71 is a device that displays the vehicle's current location or provides route guidance to the vehicle's destination while the vehicle is in motion. In this embodiment, the navigation device 71 can output, once a destination is set, at least the distance from the current location to the destination, gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the current location to the destination. The ECU 50 acquires the distance from the current location to the destination, gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the navigation device 71.

The information center 72 stores big data containing the user's vehicle usage history. The ECU 50 may obtain information from the information center 72, including the destination, planned parking time at the destination, parking location status (outdoor or indoor, etc.), weather information from the current location to the destination, and traffic congestion information from the current location to the destination.

As shown in Figure 2, the ECU 50 includes, in detail below, a normal capacity temperature adjustment unit 53, a parking schedule acquisition unit 54, a battery temperature change prediction unit 55, a target temperature determination unit 56 before the next drive, a target temperature calculation unit 57 before parking, a battery temperature determination unit 58, a driving determination unit 59, a remaining driving distance determination unit 60, a minimum capacity calculation unit 61, a minimum capacity correction unit 62, and a minimum capacity temperature adjustment unit 63. The normal capacity temperature adjustment unit 53, parking schedule acquisition unit 54, battery temperature change prediction unit 55, target temperature determination unit 56 before the next drive, target temperature calculation unit 57 before parking, battery temperature determination unit 58, driving determination unit 59, remaining driving distance determination unit 60, minimum capacity calculation unit 61, minimum capacity correction unit 62, and minimum capacity temperature adjustment unit 63 are realized by the processor 51 executing a program stored in the memory 52.

The normal temperature control unit 53 adjusts the temperature of the battery 5 so that it falls within the second temperature range described above when the distance from the vehicle's current location to the destination is greater than a predetermined distance (e.g., 10 km). By controlling the temperature of the battery 5 within the second temperature range, which is narrower than the first temperature range where the battery 5's output is limited, the temperature can be adjusted to ensure that the battery 5's output is not limited with sufficient margin.

The parking schedule acquisition unit 54 acquires the scheduled parking time from the time the vehicle arrives at its destination until the next time it drives. The parking schedule acquisition unit 54 may acquire the scheduled parking time that has been pre-entered by the user. Alternatively, the parking schedule acquisition unit 54 may predict and acquire the scheduled parking time from big data accumulated from the user's vehicle usage history.

The battery temperature change prediction unit 55 predicts the temperature change of the battery 5 during the vehicle's scheduled parking time. Preferably, the battery temperature change prediction unit 55 predicts the temperature change of the battery 5 based on the scheduled parking time acquired by the scheduled parking time acquisition unit 54, big data accumulated from the user's vehicle usage history, the ambient temperature of the parking location, and the conditions of the parking location (outdoors or indoors, etc.).

The next-trip target temperature determination unit 56 determines the target temperature of the battery 5 when the vehicle is driven again after arriving at its destination. More specifically, if the outside temperature is high and the predicted temperature change is high, the next-trip target temperature determination unit 56 determines the pre-parking target temperature between the midpoint and lower limit of the first temperature range. Conversely, if the outside temperature is low and the predicted temperature change is low, the next-trip target temperature determination unit 56 determines the pre-parking target temperature between the midpoint and upper limit of the first temperature range.

The pre-parking target temperature calculation unit 57 calculates the pre-parking target temperature from the battery temperature change predicted by the battery temperature change prediction unit 55 and the target temperature for the next drive determined by the next drive target temperature determination unit 56. Furthermore, if the calculated pre-parking target temperature is outside the first temperature range, the pre-parking target temperature calculation unit 57 sets the pre-parking target temperature to the closer of the upper or lower limit of the first temperature range.

Specifically, for example, if the calculated pre-parking target temperature is higher than the upper limit of the first temperature range, the pre-parking target temperature is set to the upper limit of the first temperature range. Also, if the calculated pre-parking target temperature is lower than the lower limit of the first temperature range, the pre-parking target temperature is set to the lower limit of the first temperature range. This prevents the pre-parking target temperature from being set outside the first temperature range, thus avoiding the limitation of the battery 5's output.

The battery temperature determination unit 58 determines whether the temperature of the battery 5, as detected by the battery temperature sensor 73, is within the second temperature range described above.

The driving determination unit 59 determines whether the vehicle is in motion. More specifically, the driving determination unit 59 may determine whether the vehicle is in motion, for example, by checking whether the shift lever (not shown) is in a position other than the P range.

The remaining distance determination unit 60 obtains the remaining distance from the current location to the destination from the navigation device 71 and determines whether the remaining distance from the current location to the destination is within a predetermined distance.

The minimum capacity calculation unit 61 calculates the minimum temperature control capacity (hereinafter referred to as "minimum capacity") required by the battery temperature control device 10 so that the battery 5 reaches the target temperature before parking by the time the vehicle arrives at its destination from its current location. Here, the minimum capacity includes the cooling capacity for cooling the battery 5 and the heating capacity for heating the battery 5 to an appropriate temperature. Furthermore, if the battery 5 is not cooled or heated to an appropriate temperature by the time the vehicle arrives at its destination from its current location (i.e., the battery temperature control device 10 is stopped), and the battery 5's temperature falls within the first temperature range, the minimum capacity may be 0. Specific examples of the minimum capacity will be described in detail later.

The minimum capacity correction unit 62 acquires gradient information from the current location to the destination, weather information (temperature, humidity, etc.) from the current location to the destination, and traffic congestion information from the current location to the destination, and corrects the minimum capacity calculated by the minimum capacity calculation unit 61.

More specifically, the minimum capacity correction unit 62 may correct the minimum capacity to increase when there are many uphill slopes from the current location to the destination, and to decrease it when there are many downhill slopes from the current location to the destination. Furthermore, the minimum capacity correction unit 62 may correct the minimum capacity to increase when there is traffic congestion from the current location to the destination.

Furthermore, when the battery 5 is being cooled, the minimum capacity correction unit 62 may correct the minimum capacity to be higher when the ambient temperature is high from the current location to the destination, and lower when the ambient temperature is low. When the battery 5 is being heated to an appropriate temperature, the minimum capacity correction unit 62 may correct the minimum capacity to be lower when the ambient temperature is high from the current location to the destination, and higher when the ambient temperature is low.

The minimum capacity temperature adjustment unit 63 controls the battery temperature control device 10 to adjust the temperature of the battery 5 at the minimum capacity from the current location until arrival at the destination. More specifically, when the minimum capacity temperature adjustment unit 63 is cooling the battery 5 in high ambient temperature conditions, it adjusts the cooling capacity by adjusting the rotation speed of the compressor 31 of the refrigeration cycle circuit 30 so that the temperature of the battery 5 reaches the pre-parking target temperature upon arrival at the destination. At this time, as shown in Figure 3, the temperature of the battery 5 is controlled to approach the pre-parking target temperature (the lower limit of the first temperature range in the example in Figure 3) at the destination, and will reach the next-trip target temperature (the upper limit of the first temperature range in the example in Figure 3) for the next trip.

Furthermore, when the minimum capacity temperature adjustment unit 63 is heating the battery 5 to an appropriate temperature in low ambient temperature conditions, it adjusts the output of the electric heater 42 in the high-temperature side cooling water circuit 40 to adjust the heating capacity, or stops the electric heater 42, so that the battery 5 maintains its minimum capacity from the current location to the destination. At this time, as shown in Figure 4, the temperature of the battery 5 is controlled to approach the pre-parking target temperature (the upper limit of the first temperature range in the example in Figure 4) at the destination, and then reaches the next-trip target temperature (the lower limit of the first temperature range in the example in Figure 4) for the next trip.

[effect]
The battery temperature control device 10 can reduce the power consumption of the battery 5. More specifically, the battery temperature control device 10 can reduce the power consumption of the battery 5 when the vehicle is parked for a predetermined time after arriving at its destination and then driven again. It can predict the temperature change of the battery 5 during the predetermined time, set a target temperature for the battery 5 before parking based on the temperature change of the battery 5 so that the temperature of the battery 5 is within a first temperature range when the vehicle is driven again, and if the distance from the vehicle's current location to the destination is less than or equal to a predetermined distance, it can reduce the power consumption of the battery 5 by calculating the minimum capacity required for the temperature of the battery 5 to reach the target temperature before parking when the vehicle arrives at the destination, and adjusting the temperature of the battery 5 with the minimum capacity from the current location to the destination.

Furthermore, the battery temperature control device 10 can accurately calculate the minimum capacity based on gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the current location to the destination, thereby reducing the power consumption of the battery 5.

[Battery temperature control]
The flow of battery temperature control by the battery temperature control device 10 will be explained using Figure 5.

In step S11, the normal temperature adjustment unit 53 adjusts the temperature of the battery 5 so that it falls within the second temperature range. In step S12, the remaining driving distance determination unit 60 determines whether the remaining distance from the current location to the destination is within a predetermined distance. If the remaining distance is within the predetermined distance, the process proceeds to step S13. If the remaining distance is greater than the predetermined distance, the process proceeds to step S11.

In step S13, the parking time acquisition unit 54 acquires the planned parking time from the time the vehicle arrives at its destination until the next time it is driven. In step S14, the battery temperature change prediction unit 55 predicts the change in the temperature of the battery 5 during the vehicle's planned parking time.

In step S15, the next pre-drive target temperature determination unit 56 determines the target temperature of the battery 5 when the vehicle will drive again after arriving at its destination. In step S16, the pre-parking target temperature calculation unit 57 calculates the pre-parking target temperature based on the battery temperature change predicted by the battery temperature change prediction unit 55 and the target temperature for the next drive determined by the next pre-drive target temperature determination unit 56.

In step S17, the battery temperature determination unit 58 determines whether the temperature of the battery 5 is within the second temperature range. If the temperature of the battery 5 is within the second temperature range, the process proceeds to step S18. If the temperature of the battery 5 is not within the second temperature range, the process proceeds to step S11.

In step S18, the driving determination unit 59 determines whether the shift lever is in a position other than the P range. If the shift lever is in a position other than the P range, the process proceeds to step S19. If the shift lever is in the P range, the process proceeds to step S11.

In step S19, the minimum capacity calculation unit 61 calculates the minimum capacity required by the battery temperature control device 10 so that the battery 5 reaches the pre-parking target temperature by the time the vehicle arrives at the destination from its current location.

In step S20, the minimum capacity correction unit 62 corrects the minimum capacity based on gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the current location to the destination. In step S21, the temperature of the battery 5 is adjusted at the minimum capacity until arrival at the destination. In step S21, the temperature of the battery 5 is adjusted at the normal capacity.

Furthermore, the present invention is not limited to the embodiments and their modifications described above, and various modifications and improvements are certainly possible within the scope of the claims of this application.

5 Battery, 10 Battery temperature control device, 20 Low-temperature side cooling water circuit, 21 First low-temperature side water pump, 22 Second low-temperature side water pump, 23 Battery heat exchanger, 24 Chiller, 25 Low-temperature side radiator, 26 Five-way valve, 30 Refrigeration cycle circuit, 31 Compressor, 32 Water-cooled condenser, 33 Evaporator, 34 Evaporator side expansion valve, 36 Chiller side expansion valve, 40 High-temperature side cooling water circuit, 41 High-temperature side water pump, 42 Electric heater, 43 Heater core, 44 High-temperature side radiator, 45 Three-way flow control valve, 50 ECU (control unit), 51 Processor, 52 Memory, 53 Normal capacity temperature control unit, 54 Parking schedule acquisition unit, 55 Battery temperature change prediction unit, 56 Next drive target temperature determination unit, 57 Pre-parking target temperature calculation unit, 58 Battery temperature determination unit, 59 Driving determination unit, 60 61 Remaining driving distance determination unit, 62 Minimum capacity calculation unit, 63 Minimum capacity correction unit, 64 Minimum capacity temperature adjustment unit, 71 Navigation device, 72 Information center, 73 Battery temperature sensor

Claims (5)

A battery temperature control device that uses the power of a vehicle-mounted traction battery to cool or heat a heat transfer medium, and uses the heat transfer medium to cool or heat the battery to an appropriate temperature to adjust the temperature of the battery,
A first temperature range is set in which the output of the battery is limited when the battery temperature is outside that range, and a second temperature range is set in which the upper limit temperature is lower and the lower limit temperature is higher than that of the first temperature range.
If the distance from the vehicle's current location to the destination is greater than a predetermined distance, the battery temperature is adjusted so that the battery temperature falls within the second temperature range.
When the distance from the vehicle's current location to the destination is less than or equal to the predetermined distance, and the vehicle is parked for a predetermined time after arriving at the destination before being driven again, the control unit predicts the temperature change, which is the change in the battery temperature during the predetermined time, determines the target temperature before the next drive, which is the target temperature of the battery when the vehicle is driven again, within the first temperature range, calculates the target temperature before parking, which is the target temperature of the battery before parking, from the temperature change and the target temperature before the next drive, and adjusts the battery temperature with the minimum capacity necessary for the battery temperature to reach the target temperature before parking when the vehicle arrives at the destination.
Battery temperature control device. A battery temperature control device according to claim 1,
If the temperature change is increasing, the control unit determines the target temperature before the next run to be within the range from the midpoint to the lower limit of the first temperature range.
Battery temperature control device. A battery temperature control device according to claim 1,
If the temperature change is decreasing, the control unit determines the target temperature before the next run to be within the range from the median to the upper limit of the first temperature range.
Battery temperature control device. A battery temperature control device according to any one of claims 1 to 3,
If the calculated pre-parking target temperature is outside the first temperature range, the control unit sets the pre-parking target temperature to the closer of the upper or lower limit of the first temperature range.
Battery temperature control device. A battery temperature control device according to any one of claims 1 to 3,
The control unit calculates the minimum capacity based on at least the distance from the current location to the destination, gradient information from the current location to the destination, weather information from the current location to the destination, and traffic congestion information from the current location to the destination.
Battery temperature control device.