METHOD FOR THE CLIMATE CONTROL OF A BATTERY ELECTRIC VEHICLE

Abstract

An electric vehicle and method for controlling an electric vehicle such as a bus include climate control of a traction or drive battery and using thermal mass or capacity of the traction battery for climate control of the vehicle cabin. The drive battery is double insulated with respect to the surroundings and kept within a desired temperature range by means of a temperature control including a cooling medium flowing around the battery. An electrical heating system for the cooling medium, an electrical compressor, and an evaporator/condenser for the cooling medium are controlled by a control system. A climate control for the passenger compartment is coupled to the temperature control by way of a heat exchanger to be supplied with heat or cold from the battery or its cooling medium.

Claims

1. An electric vehicle, comprising: a thermally insulated passenger compartment; a traction battery contained within a thermally insulated battery housing, the battery housing disposed within the thermally insulated passenger compartment; a heating and cooling system configured to heat and cool both the traction battery and the passenger compartment, comprising: an electric heating element; a first heat exchanger disposed outside of the battery housing; a blower motor configured to circulate air within the passenger compartment through the first heat exchanger; a second heat exchanger disposed within the battery housing; a fluid circuit coupled to the first and second heat exchangers and the electric heating element; and a circulating pump configured to circulate a liquid through the fluid circuit; and; a controller configured to control the electric heating element, the blower motor, and the circulating pump of the heating and cooling system to warm or cool air within the passenger compartment using thermal capacity of the traction battery.

2. The electric vehicle of claim 1, wherein the controller is further configured to operate the circulating pump and electric heating element with the blower motor off when the battery is charging, and to operate the circulating pump with the blower motor on to maintain cabin temperature when the battery is not charging.

3. The electric vehicle of claim 2, wherein the heating and cooling system further comprises: an evaporator disposed within the battery housing; an expansion valve; a condenser disposed outside of the passenger compartment; an electrical compressor disposed outside of the passenger compartment; and a refrigerant circuit containing a refrigerant and coupled to the evaporator, the expansion valve, the condenser, and the electrical compressor.

4. The electric vehicle of claim 3 wherein the controller is configured to control the compressor to cool the traction battery during charging.

5. The electric vehicle of claim 4 wherein the passenger compartment comprises at least four rows of passenger seats.

6. The electric vehicle of claim 5 wherein the electric heating element comprises a positive temperature coefficient (PTC) heating element.

7. The electric vehicle of claim 6 wherein the controller is configured to maintain traction battery temperature range between 10 and 25 degrees Celsius.

8. The electric vehicle of claim 7 wherein the traction battery has a mass of at least 1,000 kg.

9. The electric vehicle of claim 1 wherein the passenger compartment is only supplied with heat or cold from the traction battery.

10. A method for controlling an electric vehicle having a traction battery disposed within an insulated housing, which is disposed within an insulated passenger compartment, comprising: operating, by a controller, a heating and cooling system to use thermal capacity of the traction battery to heat and cool the passenger compartment, the heating and cooling system comprising a first heat exchanger disposed outside the housing and a second heat exchanger disposed within the housing, a circulating pump, and a fluid circuit coupling the first and second heat exchangers and containing a liquid circulated by the pump, the system further comprising a heating element coupled to the fluid circuit and operated by the controller to selectively heat the liquid, an evaporator/condenser and an expansion valve coupled by a refrigerant circuit to an electric compressor selectively operated by the controller to cool the liquid.

11. The method of claim 10 wherein the heating and cooling system further comprises a blower configured to circulate air through the first heat exchanger, wherein the controller is configured to operate the blower to condition the passenger compartment when the traction battery is not charging.

12. The method of claim 10 wherein the controller operates the heating and cooling system to maintain temperature of the traction battery between 10 and 25 degrees Celsius.

13. The method of claim 10 wherein the controller operates the compressor during charging of the traction battery.

14. The method of claim 10 wherein the evaporator/condenser is disposed within the housing.

15. The method of claim 10 wherein the controller is configured to operate the heating and cooling system to maintain temperature of the traction battery between 4 and 35 degrees Celsius.

16. A battery electric vehicle, comprising: a thermally insulated passenger compartment; a traction battery contained within a thermally insulated battery housing, the battery housing disposed within the thermally insulated passenger compartment; a heating and cooling system configured to heat and cool both the traction battery and the passenger compartment, comprising: an electric heating element; a first heat exchanger disposed outside of the battery housing; a blower motor configured to circulate air within the passenger compartment through the first heat exchanger; a second heat exchanger disposed within the battery housing; a fluid circuit coupled to the first and second heat exchangers and the electric heating element; a circulating pump configured to circulate a liquid through the fluid circuit; an evaporator; an expansion valve; a condenser; an electrical compressor; and a refrigerant circuit containing a refrigerant and coupled to the evaporator, the expansion valve, the condenser, and the electrical compressor; and; a controller configured to control the electric heating element, the blower motor, the circulating pump, and the compressor of the heating and cooling system to warm or cool air within the passenger compartment using thermal capacity of the traction battery.

17. The battery electric vehicle of claim 16 wherein the evaporator is disposed within the battery housing.

18. The battery electric vehicle of claim 17 wherein the condenser is disposed outside of the passenger compartment.

19. The battery electric vehicle of claim 18 wherein the electrical compressor is disposed outside the passenger compartment.

20. The battery electric vehicle of claim 19 wherein the controller is further configured to operate the heating and cooling system to maintain temperature of the traction battery between 4 and 35 degrees Celsius.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 shows a schematic side view of a passenger compartment of a bus, including indication of the drive battery and the climate control.

[0026] FIG. 2 shows the view from FIG. 1, including component parts in the cooling of the drive battery.

DETAILED DESCRIPTION

[0027] As required, detailed embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely representative and may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the claimed subject matter.

[0028] Represented in the figures is a passenger compartment, denoted overall by 1, of a battery electric minibus with four rows of seats 5, which is provided with a thermal insulation 3.

[0029] Within the thermal insulation 3 of the passenger compartment 1, usually underneath, a large drive battery 2 (in the range of at least 1,000 kg) is arranged in a further insulation 4, which comprises an insulation that is selected based on the typical vehicle surroundings.

[0030] The drive battery 2 is connected to a heating and cooling circuit 6, which according to various embodiments also serves for the climate control of the passenger compartment 1, in that the high thermal capacity of the drive battery 2 is used.

[0031] The heating and cooling circuit 6 comprises components that are connected by corresponding lines and, by means of cooling liquid, use heat or cold from the drive battery 2 for the climate control.

[0032] The heat exchange for heating and for cooling the cabin takes place by way of a liquid cooling circuit 6 (comparable with the glycol-water coolant of internal combustion engines, with the difference that it can also cool). Integrated in this circuit is an electrical high-voltage PTC heating element 7, which for conditioning the drive battery in the night is operated without the blower motor to attain or maintain a desired battery temperature. Also included is a downstream heat exchanger 8, which is operated with the blower motor when the thermal exchange with the cabin air L of the passenger compartment 1 is desired, and comprises a heat exchanger 9, which is arranged within the battery insulation 4 or the cooling liquid flow thereof, and a circulating pump 10 for the cooling medium.

[0033] Therefore, by way of the heat exchanger 8, the coolant circuit 6 can, depending on the setting, warm or cool the air L of the passenger compartment 1 by using the thermal capacity of the drive battery 2.

[0034] If necessary, the temperature of the cooling liquid in the heating circuit 6 may be changed by means of the high-voltage PTC heating element 7. For the conditioning of the drive battery, the blower motor in this case remains switched off and only the water-side PTC element and the water pump remain switched on. Therefore, downstream of the water-side PTC element, warm water is returned for conditioning the drive battery. This setting should be used for conditioning the battery overnight when days are cold.

[0035] Since the drive battery 2 has a very great thermal capacity in comparison with the required amount of heat or cold, this capacity can be used for the climate control of the passenger compartment, without its temperature being changed substantially. The insulation of the cabin assists this process.

[0036] As can be seen from FIG. 2, the drive battery 2 is also provided with a refrigerant circuit 11, by means of which, during the electrical charging, the drive battery 2 can be brought back or cooled down to a desired temperature range, which is about 12 degrees Celsius in one embodiment. In various embodiments, the temperature range of the temperature control of the drive battery lies between 4 and 35 degrees Celsius. In other embodiments the temperature range is between 10 and 25 degrees Celsius and may be at or around 12 degrees Celsius, for example, or a temperature that is close to the minimum daytime temperatures in summer to provide sufficient heat for the interior space even in the transitional time.

[0037] The refrigerant circuit 11 comprises an evaporator 12, which is arranged within the battery insulation 4 or the coolant volume thereof, an expansion valve 13, a condenser 14 and also an electrical compressor 15, which by contrast with the evaporator 12 are arranged outside the passenger cabin insulation, so that their waste heat or cold can be exchanged in the surroundings.

[0038] The passenger compartment 1 may also have a supply of fresh air F and a removal V of stale air.

[0039] While representative embodiments are described above, it is not intended that these embodiments describe all possible forms of the claimed subject matter. The words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the claimed subject matter. Additionally, the features of various implementing embodiments may be combined to form further embodiments that may not be explicitly illustrated or described.