VEHICLE BATTERY COOLING DEVICE

The battery cooling device that cools a battery by circulating a refrigerant by a compressor and cools air blown into a vehicle compartment, and when the battery is being rapidly charged, the rotation speed of the compressor is increased. More specifically, the upper limit rotation speed of the compressor is increased to a predetermined rotation speed. At this time, the predetermined number of revolutions is determined based on a maximum allowable noise level at the time of rapid charge of the battery.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to Japanese Patent Application No. 2023-016636 filed on Feb. 7, 2023, which is incorporated herein by reference in its entirety including the specification, claims, drawings, and abstract.

TECHNICAL FIELD

The present disclosure relates to a vehicle battery cooling device for controlling during rapid charging of a battery.

BACKGROUND

A traveling battery mounted on a vehicle generates heat by charging and discharging, and battery characteristics such as discharge characteristics are degraded due to temperature rise due to heat generation. Therefore, the battery is cooled so that the temperature of the battery does not rise too much. In particular, when the travel battery mounted on a vehicle is rapidly charged, it is necessary to sufficiently cool the battery. For example, JP2007-336691 discloses a technology for increasing the cooling capability of a battery by increasing the rotation speed of a cooling fan of the battery during rapid charging.

SUMMARY

The vehicle battery cooling device may cool the battery by circulating the refrigerant by the compressor. In this device, the cooling capacity can be increased by increasing the rotation speed of the compressor. Therefore, in this device, there is room for reducing the rapid charge time by increasing the cooling capacity of the battery during rapid charge.

Accordingly, an object of the present disclosure is to provide a vehicle battery cooling device capable of shortening the rapid charge time.

A vehicle battery cooling device according to the present disclosure cools a battery by circulating a refrigerant by a compressor and cools air supplied into a vehicle compartment, wherein when the battery is being rapidly charged, rotation speed of the compressor is increased.

According to the above configuration, it is possible to increase the cooling capability of the battery during rapid charging and shorten the rapid charging time.

In some embodiments of the vehicle battery cooling device according to the present disclosure, the upper limit rotation speed of the compressor is increased when the battery is being rapidly charged.

In some embodiments of the vehicle battery cooling device according to the present disclosure, when the battery is rapidly charged and the cooled air is blown into the vehicle compartment, a target supply temperature for the cooled air blown into the vehicle compartment is raised.

According to the above configuration, since the cooling capability of the air conditioner decreases, the cooling capability of the battery increases, and the rapid charge time can be shortened.

In some embodiments of the vehicle battery cooling device according to the present disclosure, the increase in the upper limit rotation speed is determined based on a maximum allowable noise level during rapid charging of the battery.

According to the above configuration, even when the rotation speed of the compressor is increased, the maximum allowable noise level at the time of rapid charge of the battery is not exceeded.

According to the vehicle battery cooling device of the present disclosure, it is possible to shorten the rapid charge time of the battery.

DESCRIPTION OF EMBODIMENTS

Hereinafter, an example of an embodiment of the present disclosure will be described in detail. In the following description, specific shapes, materials, directions, numerical values, and the like are examples for facilitating understanding of the present disclosure, and can be appropriately changed in accordance with applications, purposes, specifications, and the like.

A battery cooling device10as a vehicle battery cooling device cools a traveling battery20by circulating a refrigerant by a compressor11, and cools air blown into the vehicle compartment6. According to the battery cooling device10, the rapid charge time of the battery20can be shortened, as will be described later in detail.

Vehicles

A vehicle5according to an embodiment will be described with reference toFIG.1.

As shown inFIG.1, a battery cooling device10as a vehicle battery cooling device is provided in a vehicle5. The vehicle5includes a battery cooling device10, the traveling battery20, an air conditioner30for conditioning air in the vehicle compartment6, and ECU50(Electronic Control Unit) serving as a control unit for controlling each device of the battery cooling device10and the air conditioner30.

The vehicle5is an electric vehicle that runs using a motor as power, but may be, for example, a hybrid vehicle that runs using an engine and a motor as power.

In some embodiments, a rechargeable secondary battery is used as the battery20. The battery20can be rapidly charged by a direct current by a dedicated quick charger. The battery20is provided with a battery temperature sensor21for detecting a temperature of the battery20, a battery voltage sensor22for detecting a voltage of the battery20, and a battery current sensor23for detecting a current related to charge and discharge of the battery20(seeFIG.2).

Battery Cooling Device

The battery cooling device10and the air conditioner30, which are examples of the embodiment, will be described with reference toFIG.2. The battery cooling device10circulates the refrigerant by a vapor compression refrigeration cycle, cools the battery20by circulating the refrigerant in the battery cooler13, and cools the air blown into the vehicle compartment6by circulating the refrigerant in the evaporator15of the air conditioner30, which will be described later. The battery cooling device10includes a compressor11that compresses a refrigerant gas, a condenser12that condenses a high-temperature and high-pressure refrigerant gas discharged from the compressor11, a battery cooler13that cools the battery20, a first expansion valve14that adjusts the circulation amount of the refrigerant in the battery cooler13, an evaporator15that cools the air blown into the vehicle compartment6in the air conditioner30, and a second expansion valve16that adjusts the circulation amount of the refrigerant in the evaporator15.

The compressor11is driven by an electric motor (not shown), and by changing the frequency of the electric motor, the rotation speed can be changed to change the output.

The air conditioner30includes an air passage31through which air for cooling and/or heating air blown into the vehicle compartment6passes, and a heating circuit36for heating air supplied to the vehicle compartment6. Further, the air conditioner30includes an operation unit41capable of changing the set temperature of the vehicle interior6, an internal air temperature sensor42for detecting the temperature of the vehicle interior6, and an outside air temperature sensor43for detecting the outside air temperature of the vehicle5(seeFIG.1).

The air conditioner30further includes a blower32, an inside/outside air switching door33, an evaporator15, a heater core34, and an air mix door35. The blower32generates an air flow toward the vehicle compartment6in the air passage31. The inside/outside air switching door33switches the introduction of air (inside air) in the vehicle compartment6or the introduction of air (outside air) outside the vehicle5. The evaporator15is provided in the battery cooling device10and cools the air passing through the air passage31. The heater core34is connected to the heating circuit36and heats the air passing through the air passage31. The air mix door35opens and closes an air passage31passing through the heater core34.

The heating circuit36is a circuit that circulates water heated by the heater37as a heat source to heat air passing through the air passage31by the heater core34. The heating circuit36has an output adjustable, and includes a heater37for heating water circulating in the heating circuit36, a heater core34provided in the air passage31as described above for heating air passing through the air passage31, and a pump38for circulating water in the heating circuit36.

Referring toFIGS.2and3, an ECU50as a control unit will be described.

As shown inFIGS.2and3, the ECU50as a control unit controls each device of the battery cooling device10and the air conditioner30, as described above. The ECU50includes a CPU (Central Processing Unit) serving as an arithmetic processing unit, a storage unit such as a RAM (Random Access Memory) and a ROM (Read Only Memory), and performs signal processing according to a program stored in advance in the ROM while using a temporary storage function of the RAM.

In the present embodiment, the ECU50controls each device of the battery cooling device10and the air conditioner30. The ECU for controlling each device of the battery cooling device10and the ECU for controlling each device of the air conditioner30may be different ECUs.

The ECU50is connected to the compressor11, the first expansion valve14, the second expansion valve16, the blower32, the inside/outside air switching door33, the air mix door35, the heater37, and the pump38, and transmits signals to them. The ECU50is connected to the battery temperature sensor21, the battery voltage sensor22, and the battery current sensor23and receives signals from the battery temperature sensor21, the battery voltage sensor22, and the battery current sensor23. Further, the ECU50is connected to the operation unit41, the inside air temperature sensor42, and the outside air temperature sensor43and receives signals from them.

The ECU50includes a battery temperature determination unit51, a battery cooling unit52, a rapid charge determination unit53, a compressor rotation speed increase unit54, a cooling determination unit55, and a target supply temperature increase unit56. The battery temperature determination unit51, the battery cooling unit52, the rapid charge determination unit53, the compressor rotation speed increase unit54, the cooling determination unit55, and the target supply temperature increase unit56are implemented by the CPU executing a program stored in the ROM or the RAM.

The battery temperature determination unit51determines whether or not the battery temperature detected by the battery temperature sensor21is equal to or higher than a predetermined temperature. In some embodiments, the predetermined temperature is determined based on a temperature at which battery characteristics such as discharge characteristics are degraded.

The battery cooling section52cools the battery20by the battery cooler13when the battery temperature is equal to or higher than a predetermined temperature. More specifically, the refrigerant is circulated in the battery cooler13by operating the compressor11, and the refrigerant circulation amount of the battery cooler13is adjusted by the first expansion valve14. The rotation speed of the compressor11and the opening degree of the first expansion valve14may be adjusted by the battery temperature. According to the battery cooling section52, it is possible to avoid a decrease in battery characteristics such as discharge characteristics of the battery20.

The rapid charge determination unit53determines whether or not the charge is rapid charge based on the current and voltage at the time of charge of the battery20detected by the battery voltage sensor22and the battery current sensor23. When separate connectors are used, rapid charging and ordinary charging may be determined based on the connectors (charging circuits) used.

When the battery20is cooled during rapid charging of the battery20, the compressor rotation speed increasing unit54increases the rotation speed of the compressor11of the battery cooling device10. More specifically, the upper limit rotation speed of the compressor11is increased to a predetermined rotation speed to enable the compressor11to operate to a predetermined rotation speed. As a result, when the battery temperature rises, the rotation speed of the compressor11can rise to a predetermined rotation speed, and the cooling capability of the battery cooling device10can be increased during rapid charging to shorten the rapid charging time.

In the compressor rotation speed increasing section54, the predetermined rotation speed is determined based on the maximum allowable noise level at the time of rapid charge of the battery20. More specifically, the predetermined number of revolutions is determined such that the noise level due to the number of revolutions of the predetermined number of revolutions is equal to or lower than the maximum allowable noise level at the time of rapid charge of the battery20. The maximum allowable noise level at the time of rapid charging is the maximum allowable level of the noise level generated from the rapid charger and the vehicle5at the time of rapid charging of the battery20of the vehicle5.

Thus, even when the rotation speed of the compressor11is increased during rapid charging, it is possible to avoid exceeding the maximum allowable noise level at the time of rapid charging of the battery20. In other words, by increasing the rotation speed of the compressor11to the maximum allowable noise level at the time of rapid charging of the battery20, the cooling capability of the battery cooling device10can be increased during rapid charging to shorten the rapid charging time.

In the present embodiment, the upper limit rotation speed of the compressor11is increased to a predetermined rotation speed. However, the present disclosure is not limited thereto. For example, the current rotation speed of the compressor11may be increased by a predetermined rotation speed width, or the current rotation speed of the compressor11may be increased to a predetermined rotation speed.

The cooling determination unit55determines whether or not the air conditioner30is performing the cooling operation. In other words, the cooling determination unit55determines whether or not the battery cooling device10cools the air supplied to the vehicle interior6. Specifically, the cooling determination unit55may determine whether or not the refrigerant circulates in the evaporator15by the opening degree of the second expansion valve16.

The cooling operation is executed when the inside air temperature in the vehicle compartment6detected by the inside air temperature sensor42is higher than the target supply temperature. The target supply temperature is a target temperature of air supplied from the blowout port of the air passage31into the vehicle interior6based on the set temperature of the vehicle interior6set by the operation unit41, the inside air temperature of the vehicle interior6detected by the inside air temperature sensor42, and the outside air temperature of the vehicle5detected by the outside air temperature sensor43.

In the cooling operation, the refrigerant is circulated in the evaporator15by operating the compressor11, the refrigerant circulation amount of the evaporator15is adjusted by the second expansion valve16, and the air passing through the air passage31is cooled by the evaporator15. The rotation speed of the compressor11and the opening degree of the second expansion valve16may be adjusted by the target supply temperature.

The target supply temperature increasing unit56increases the target supply temperature by a predetermined temperature when the battery20is rapidly charged and the air conditioner30is in the cooling operation. Thereby, the refrigerant circulation amount of the evaporator15decreases, and the refrigerant circulation amount of the battery cooler13increases. As a result, the cooling capability of the battery20increases, and the rapid charge time can be shortened.

The flow of the battery cooling control will be described with reference toFIG.4.

In the battery cooling control, the battery cooling device10cools the battery20based on each function of the ECU50described above in accordance with the following procedure. In step S11, the battery temperature determination unit51determines whether or not the battery temperature detected by the battery temperature sensor21is equal to or higher than a predetermined temperature. When the battery temperature is equal to or higher than the predetermined temperature, the process proceeds to step S12.

In step S12, the battery cooling unit52cools the battery20. More specifically, the refrigerant is circulated in the battery cooler13by operating the compressor11, and the refrigerant circulation amount of the battery cooler13is adjusted by the first expansion valve14. The rotation speed of the compressor11and the opening degree of the first expansion valve14may be adjusted by the battery temperature.

In step S13, the rapid charge determination unit53determines whether or not the charge is rapid charge based on the current and voltage at the time of charge of the battery20detected by the battery voltage sensor22and the battery current sensor23. In the case of rapid charging, the process proceeds to step S14.

In step S14, the compressor rotation speed increasing unit54increases the upper limit rotation speed of the compressor11of the battery cooling device10to a predetermined rotation speed to enable the compressor11to operate to a predetermined rotation speed. The predetermined number of revolutions is determined based on the maximum allowable noise level when the battery20is rapidly charged. More specifically, the predetermined number of revolutions is determined such that the noise level due to the number of revolutions of the predetermined number of revolutions is equal to the maximum allowable noise level at the time of rapid charge of the battery20.

In step S15, the cooling determination unit55determines whether or not the air conditioner30is performing the cooling operation. When the cooling operation is being performed, the process proceeds to step S16. In step S16, the target supply temperature increasing unit56increases the target supply temperature by a predetermined temperature.

It should be noted that the present disclosure is not limited to the above-described embodiments and modifications thereof, and it is needless to say that various changes and modifications can be made without departing from the scope of the claims of the present application.

In the battery cooling device10of the present embodiment, the battery20is cooled by circulating the refrigerant in the battery cooler13. However, the present disclosure is not limited thereto. The present disclosure may have a configuration in which a cooling medium is circulated in a heat exchanger with cooling water by a battery cooling device to cool the cooling water, and the battery20is cooled by the cooling water.