SYSTEM FOR COOLING A BATTERY OF A MOTOR VEHICLE, AND MOTOR VEHICLE

Abstract

A system for cooling a battery of an electrified vehicle includes a vehicle air-conditioning system having a first cooling circuit in which a first cooling medium circulates, a second cooling circuit in which a second cooling medium circulates, a cooling unit in thermal contact with the battery, wherein the second cooling medium flows through the cooling unit, and with a heat exchanger through which the first and second cooling media flow in separate channels which are in thermal contact, wherein in the heat exchanger, heat is discharged from the second cooling medium towards the first cooling medium.

Claims

1. An electrified vehicle comprising: an air-conditioning system including a first cooling circuit in which a first cooling medium circulates; a second cooling circuit in which a second cooling medium circulates; a cooling unit in thermal contact with a traction battery, wherein the second cooling medium flows through the cooling unit; and a heat exchanger through which the first and second cooling media flow in separate channels which are in thermal contact, wherein in the heat exchanger, heat is discharged from the second cooling medium and absorbed by the first cooling medium.

2. The electrified vehicle of claim 1 wherein the air-conditioning system includes a plurality of function units arranged in a circulation direction of the first cooling medium in the first cooling circuit, the plurality of function units comprising: a compressor; a condenser; an expansion valve; and an evaporator, wherein the first cooling medium flows through each of the function units.

3. The electrified vehicle of claim 2 further comprising a first line portion of the first cooling circuit provided between the evaporator and the compressor, wherein the first line portion passes through the heat exchanger.

4. The electrified vehicle of claim 3 further comprising a second line portion of the second cooling circuit, wherein the second line portion passes through the heat exchanger.

5. The electrified vehicle of claim 1, further comprising: a first line portion of the first cooling circuit provided between the evaporator and the compressor and passing through the heat exchanger; and a second line portion of the second cooling circuit passing through the heat exchanger, wherein the first line portion of the first cooling circuit and the second line portion of the second cooling circuit pass at least partially coaxially through the heat exchanger.

6. The electrified vehicle of claim 1 further comprising: a first line portion of the first cooling circuit provided between the evaporator and the compressor and passing through the heat exchanger; a second line portion of the second cooling circuit passing through the heat exchanger; and a pump configured to circulate the second cooling medium through the second cooling circuit and through the heat exchanger in a flow direction opposite a flow direction of the first cooling medium through the heat exchanger.

7. The electrified vehicle of claim 1 wherein the cooling unit comprises a cooling coil at least partially surrounding the traction battery.

8. The electrified vehicle of claim 1 further comprising at least one cooling circuit temperature sensor arranged in each of the first and second cooling circuits and configured to detect temperature of the first and second cooling media, respectively.

9. The electrified vehicle of claim 8 further comprising a battery temperature sensor configured to provide a signal indicative of temperature of the traction battery.

10. The electrified vehicle of claim 9 further comprising a controller in communication with the at least one cooling circuit temperature sensor and the battery temperature sensor, the controller configured to control the air-conditioning system in response to the signal from the battery temperature sensor.

11. A vehicle system comprising: an air conditioning system including a compressor, a condenser, an expansion valve, and an evaporator coupled by a first cooling circuit configured for circulating a first cooling medium; a traction battery; a cooling coil at least partially surrounding the traction battery; a pump coupled to a second cooling circuit and configured to circulate a second cooling medium through the cooling coil; a heat exchanger coupled to the first cooling circuit and the second cooling circuit; a first temperature sensor configured to provide a signal responsive to temperature of the first cooling medium; a second temperature sensor configured to provide a signal responsive to temperature of the second cooling medium; and a controller configured to control the air conditioning system in response to at least the signals from the first and second temperature sensors to selectively cool the traction battery.

12. The vehicle system of claim 11 wherein the pump is configured to circulate the second cooling medium through the heat exchanger in a counter flow direction relative to the first cooling medium flowing through the heat exchanger.

13. The vehicle system of claim 12 wherein the first cooling circuit includes a first line portion passing through the heat exchanger and the second cooling circuit includes a second line portion passing through the heat exchanger, and wherein the first line portion is coaxially arranged relative to the second line portion.

14. A method for cooling a traction battery of an electrified vehicle having an air conditioning system, the method comprising: circulating a first cooling medium through a vehicle air conditioning circuit of the air conditioning system and a first line portion of a heat exchanger; and circulating a second cooling medium through a second line portion of the heat exchanger and through a cooling unit of the traction battery.

15. The method of claim 14 further comprising controlling the air conditioning system based on temperature of the second cooling medium.

16. The method of claim 15 wherein circulating the second cooling medium comprises operating a pump to circulate the second cooling medium in a counterflow direction of the first cooling medium through the heat exchanger.

17. The method of claim 14 wherein circulating the second cooling medium comprises circulating the second cooling medium coaxially with the first cooling medium through the first and second line portions of the heat exchanger.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic diagram of a battery cooling system having first and second cooling circuits.

DETAILED DESCRIPTION

[0034] 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 figure is 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.

[0035] FIG. 1 shows a flow diagram of a system for cooling a battery 1 of a motor vehicle. As stated, the motor vehicle is in particular an electric vehicle. The system comprises a vehicle air-conditioning system 2 (A/C system) which has a first cooling circuit K1 in which a first cooling medium circulates. The system furthermore comprises a second cooling circuit K2 in which a second cooling medium circulates. The battery 1 is in thermal contact with a cooling unit 3 (and in particular is surrounded by this), wherein the second cooling medium flows through the cooling unit 3. The cooling unit 3 is part of the second cooling circuit K2.

[0036] As shown in the figure, the vehicle air-conditioning system 2 comprises a plurality of function units which are arranged successively in relation to a circulation direction Z1 of the first cooling medium in the first cooling circuit K1, namely a compressor 7, a condenser 8, an expansion unit 9 and an evaporation unit 10, wherein the first cooling medium flows through each function unit. In the illustration in FIG. 1, the circulation directions Z1, Z2 of the first and second cooling media through the heat exchanger 4 are in co-flow, but this need not necessarily be the case, since also contraflow circulation directions Z1, Z2 of the first and second cooling media are possible.

[0037] The circulation of the first cooling medium is driven by the compressor 7. The first cooling circuit K1 has a high-pressure side and a low-pressure side, wherein the high-pressure side is formed by the region arranged between the compressor 7 and the expansion unit 9, and the low-pressure side is formed by the region arranged between the expansion unit 9 and the compressor 7.

[0038] Gaseous first cooling medium is compressed in the compressor 7 and thereby heated. Then it is conveyed under high pressure through the condenser 8, wherein heat is extracted from the first cooling medium (which is warm at this point). As a result, the first cooling medium condenses, i.e. transforms from the gaseous to the liquid state.

[0039] Then the now liquid first cooling medium flows to the expansion unit 9 which is configured as an expansion valve. The valve ensures that an even pressure is maintained upstream of the valve, whereas the pressure after the expansion valve may be reduced by volume enlargement. Since the expansion valve is positioned directly upstream of the evaporation unit 10 in the circulation direction Z1 of the first cooling medium, the first cooling medium expands into the evaporation unit 10. It thus changes its aggregate state from liquid to gaseous. In this physical process, the first cooling medium extracts heat from the environment, which may be perceived as evaporative cooling in the passenger compartment.

[0040] A heat exchanger 4 is arranged between the evaporation unit 10 and the compressor 7, through which the first and second cooling media flow in separate channels 5, 6 which are in thermal contact, wherein in the heat exchanger 4, heat is dissipated from the second cooling medium towards the first cooling medium. Depending on the temperature of the first and second cooling media, heat may also be dissipated towards the second cooling medium, whereby heating of the battery 1 is possible. The channel 5 is formed by a line portion L1 of the first cooling circuit K1, which is provided between the evaporation unit 10 and the compressor 7 and passes through the heat exchanger 4. The channel 6 is formed by a line portion L2 of the second cooling circuit K2.

[0041] The line portion L1 of the first cooling circuit K1 and the line portion L2 of the second cooling circuit K2 pass at least partially coaxially through the heat exchanger 4. In the present example, the line portion L2 provides an inner channel 6, and the line portion L1 provides an outer channel 5 surrounding the inner channel 6. In cross-section, the channels 5, 6 are arranged concentrically. A wall 11 between the channels 5, 6 prevents a substance exchange between the first and second cooling media, but at the same time allows heat transport.

[0042] 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.