Thermal Management System, Vehicle and Method for Operating Two Cooling Circuits of a Thermal Management System

Abstract

A thermal management system for use in a vehicle includes a first cooling circuit for cooling a battery; and a second cooling circuit for cooling an electric motor configured to drive the vehicle. The first and second cooling circuits are connected to each other: (a) in series by a multi-way valve in a first mode of the thermal management system and in a first valve position of the multi-way valve, or (b) in parallel in a second mode of the thermal management system and in a second valve position of the multi-way valve. In a third mode of the thermal management system and in a third valve position, the multi-way valve is configured to take up an intermediate position in which coolant flows of the first and second cooling circuits are mixed with each other as needed.

Claims

1-18. (canceled)

19. A thermal management system (2) for use in a vehicle, comprising: a first cooling circuit (4) for cooling a battery (10); and a second cooling circuit (6) for cooling an electric motor (12) configured to drive the vehicle, wherein the first and second cooling circuits (4, 6) are connected to each other: (a) in series by a multi-way valve (14) in a first mode of the thermal management system (2) and in a first valve position of the multi-way valve (14), or (b) in parallel in a second mode of the thermal management system (2) and in a second valve position of the multi-way valve (14), wherein, in a third mode of the thermal management system (2) and in a third valve position, the multi-way valve (14) is configured to take up an intermediate position in which coolant flows of the first and second cooling circuits (4, 6) are mixed with each other as needed.

20. The thermal management system (2) as claimed in claim 19, wherein the multi-way valve (14) is configured as a 4/2-way valve.

21. The thermal management system (2) as claimed in claim 20, wherein the thermal management system (2) further comprises a further multi-way valve (18) in the second cooling circuit (6) downstream of the electric motor (12), the further multi-way valve (18) being configured to conduct a coolant flow optionally via a path (22) with a radiator (24) and/or via a bypass path (20) parallel to the path (22) so as to bypass the radiator (24).

22. The thermal management system (2) as claimed in claim 21, wherein the further multi-way valve (18) is configured as a 3/2-way valve.

23. The thermal management system (2) as claimed in claim 19, wherein the multi-way valve (14) is configured as a 5/3-way valve which is fluidically connected to a bypass path (20) of the second cooling circuit (6) for bypassing a radiator (24) and to a path (22) parallel thereto with a radiator (24), wherein the bypass path (20) and the radiator path (22) originate from a junction (KP) downstream of the electric motor (12).

24. The thermal management system (2) as claimed in claim 19, wherein the third valve position can be set from a plurality of possible intermediate positions.

25. The thermal management system (2) as claimed in claim 24, wherein the individual intermediate positions can be set in increments or infinitely variably.

26. A vehicle comprising the thermal management system (2) as claimed in claim 19.

27. A method for operating the first and second cooling circuits (4, 6) of the thermal management system (2) as claimed in claim 19, the method comprising: cooling the battery (10) using the first cooling circuit (4); cooling the electric motor (12) using the second cooling circuit (6) to cool the electric motor (12); connecting the first and second cooling circuits (4, 6) to each other: in series by the multi-way valve (14) in the first mode of the thermal management system (2) and in the first valve position of the multi-way valve (14), or in parallel in the second mode of the thermal management system (2) and in the second valve position of the multi-way valve (14); and switching the multi-way valve (14) in a third mode of the thermal management system (2) and in a third valve position, into an intermediate position in which the coolant flows of the first and second cooling circuits (4, 6) are mixed with each other as needed.

28. The method as claimed in claim 27, wherein a 4/2-way valve is used as the multi-way valve (14).

29. The method as claimed in claim 28, wherein a further multi-way valve (18) is used in the second cooling circuit (6) downstream of the electric motor (12), through which a coolant flow is conducted optionally via a path (22) with a radiator (24) and/or via a path (20) parallel thereto (bypass path 20) for bypassing the radiator (24).

30. The method as claimed in claim 29, wherein a 3/2-way valve is used for the further multi-way valve (18).

31. The method as claimed in claim 27, wherein a 5/3-way valve is used as the multi-way valve (14), which is fluidically connected to a bypass path (20) of the second cooling circuit (6) for bypassing a radiator (24) and to a path (22) parallel thereto with a radiator (24), wherein the bypass path (20) and the radiator path (22) originate from a junction (KP) downstream of the electric motor (12).

32. The method as claimed in claim 27, wherein the third valve position is set from a plurality of possible intermediate positions.

33. The method as claimed in claim 32, wherein the individual intermediate positions are set in increments or infinitely variably.

34. The method as claimed in claim 29, wherein a fourth mode (or bypass mode) and/or a fifth mode of the system is set, wherein, in the fourth mode, coolant is conducted via the bypass path (20) for heating the battery (10), whereas, in the fifth mode, coolant is conducted via the radiator path (22) for cooling the battery (10).

35. A non-volatile computer readable medium storing a computer program which, when executed on a computer, controls carrying out the method as claimed in claim 27.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The invention will be explained below in detail with reference to illustrations in figures. Further advantageous developments of the invention are apparent from the dependent claims and the description below of preferred embodiments. For this purpose, in the figures:

[0025] FIG. 1 shows a thermal management system in a proposed first embodiment;

[0026] FIG. 2 shows an extract from the thermal management system shown in FIG. 1;

[0027] FIG. 3 shows a thermal management system in a proposed second embodiment;

[0028] FIG. 4 shows a first and second illustration of volume flows at a 4/2-way valve of the proposed first embodiment;

[0029] FIG. 5 shows a third illustration of volume flows at a 3/2-way valve of the first embodiment;

[0030] FIG. 6 shows a first and second illustration of volume flows at a 5/3-way valve of the proposed second embodiment; and

[0031] FIG. 7 shows a third illustration of volume flows at the 5/3-way valve of the second embodiment.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0032] The thermal management system 2 according to FIG. 1 and FIG. 2 illustrates a first cooling circuit 4 for a battery 10 and a second cooling circuit 6 for an electric motor 12 for driving the vehicle, as well as a refrigerant circuit 8 of an air conditioning system. The vehicle can be, for example, a battery electric vehicle (Battery Electric Vehicle, for short: BEV), a hybrid electric vehicle (Hybrid Electric Vehicle, for short: HEV) or a fuel cell vehicle (Fuel Cell Electric Vehicle, for short: FCEV). These three different circuits 4, 6, 8 merge to a certain extent with one another. The respective fluid is conveyed in the two cooling circuits 4, 6 by a dedicated electric pump 16, 17.

[0033] The electric motor 12 and the power electronics LE should be operated at a coolant or cooling water temperature of approx. 85° C. The battery 10 or the battery cells, by contrast, should be operated in a specific coolant or cooling water temperature window between 20° C. and 40° C. because this ensures an optimal operating temperature range for the battery 10. The temperature of the battery 10 or of the individual battery cells themselves can definitely exceed the 40° C. temperature threshold. The two cooling circuits 4, 6 are therefore required. The two cooling circuits 4, 6 have to be able to both absorb and dissipate heat. While the battery cooling circuit 4 is cooled via a heat exchanger Ch (cf. FIG. 1; see chiller, for short: Ch) in relation to the refrigerant circuit 8, the electric motor cooling circuit 6 can be cooled in relation to the environment via a radiator 24 and in relation to the battery cooling circuit 4 via a multi-way valve 14 described below (Coolant Flow Control Valve, for short: CFCV), wherein the multi-way valve 14 is an interface between the battery cooling circuit 4 and the electric motor cooling circuit 6. The battery cooling circuit 4 can also be cooled via the radiator 24 in an appropriate valve position of the multi-way valve 14. However, since the battery coolant should not exceed a temperature of 40° C., the cooling via the radiator 24 is usually insufficient, and therefore heat has to be dissipated via the heat exchanger Ch. In addition to the electric motor 12 and the power electronics LE, a charger (for short: C) is also to be cooled in the electric motor cooling circuit 6. A temperature sensor CTS is provided for controlling the respective cooling circuit 4, 6. A resistance heater PTC is also provided in the battery cooling circuit 4. The electric motor 12 is either water-cooled or oil-cooled. In the latter case, a corresponding oil cooling circuit of the electric motor 12 is connected to the motor cooling circuit 6 by a heat exchanger (not shown).

[0034] The thermal management system 2 can be operated in different modes by the multi-way valve 14. The multi-way valve 14 here is part of what is referred to as an actuator or cooling water control valve, which as such also comprises a drive with an electric servomotor and a controller for controlling the electric servomotor.

[0035] In a first mode of the system (Use Case 1, for short: UC1=series connection R with maximum heat recovery) and in a first valve position of the multi-way valve 14, the cooling circuit 4 can be connected in series with the cooling circuit 6. With respect to the multi-way valve 14, coolant flows via an inlet or input a from the cooling circuit 6 via the outlet or output c into the cooling circuit 4 and finally via the inlet or input d from the cooling circuit 4 via the outlet or output b back into the cooling circuit 6.

[0036] This series connection causes the battery cooling circuit 4 to heat rapidly, utilizing the waste heat from the electric motor 12 and the power electronics LE. The electric motor cooling circuit 6 thus also has the function of a heating circuit.

[0037] In a second mode of the system (Use Case2, for short: UC2=parallel connection P with overheating protection) and in a second valve position of the multi-way valve 14, the cooling circuit 4 can be connected parallel to the cooling circuit 6, such that the two cooling circuits 4, 6 are fluidically separated from each other. This separation protects the battery 10 from overheating.

[0038] In addition, a third mode of the system (Use Case 3, for short: UC3=mixing mode M with selective heat recovery) is also proposed, in which the multi-way valve 14 is switched to an intermediate position—i.e., a third valve position—in which the coolant flows of the two cooling circuits 4, 6 are mixed with each other as needed.

[0039] Such a mixing mode allows both the temperature of the battery 10 and the temperature of the electric motor 12 to be controlled more precisely. There are no high pressure and temperature jumps in the two cooling circuits 4, 6, since there is no switching between the series connection mode R and the parallel connection mode.

[0040] In a first embodiment (cf. FIG. 1 and FIG. 2), the multi-way valve 14 is designed in the form of a 4/2-way valve, via which the previously described system modes and valve positions can be set or controlled. Here, in the cooling circuit 6 downstream of the electric motor 12, a further multi-way valve 18 in the form of a 3/2-way valve is also provided, the outlet or output of which al is fluidically connected to the inlet or input a of the 4/2-way valve 14. The multi-way valve 18 is also part of a further actuator or cooling water control valve, which as such also comprises a drive with an electric servomotor and a controller for controlling the electric servomotor.

[0041] By the 3/2-way valve 18, a coolant flow can optionally be conducted via a path 22 with a radiator 24 and/or via a path 20 parallel thereto—bypass path 20—for bypassing the radiator 24.

[0042] FIG. 4 illustrates the volume flows VS, which can be set with respect to the 4/2-way valve of the first embodiment. The input a and the two outputs b, c are seen here on the left of the graph. By contrast, input d and the two outputs b, c are seen on the right of the graph. In the two graphs, a left and right area are each shown without a significant change in terms of the volume flows. The left area describes the UC1 mode or the series connection R. The right area, on the other hand, describes the UC2 mode or the parallel connection P.

[0043] Between these two modes, a middle area with a multiplicity of intermediate positions of the valve 14 can be controlled so as to bring about a needs-based mixing of the coolant flows of the cooling circuits 4, 6 (mixing mode M=UC3). In principle, discrete intermediate positions can be set in increments. As an alternative thereto, the intermediate positions can also be set, however, infinitely variably or continuously over the entire middle area in order to enable even more precise control of the temperature both of the battery 10 and the electric motor 12.

[0044] In an alternative second embodiment (cf. FIG. 3), the multi-way valve 14 is configured in the form of a 5/3-way valve. An inlet or input e of the 5/3-way valve that protrudes from the plane in FIG. 3 should also be imagined here, which inlet or input as such is fluidically connected via a bypass path 20 to a junction KP (or the outlet a.sup.I thereof) downstream of the electric motor 12, wherein both the bypass path 20 and a path 22 parallel thereto with a radiator 24 originate from the junction KP. The radiator path 22 fluidically connects the junction KP (or the outlet c.sup.I thereof) to the inlet or input a of the 5/3-way valve.

[0045] FIG. 6 illustrates—analogously to FIG. 4—the volume flows VS which can be set with respect to the 5/3-way valve of the second embodiment. The input a and the two outputs b, c are seen here on the left of the graph. By contrast, input d and the two outputs b, c are seen on the right of the graph. Also in these two graphs, a left and right area are each illustrated without a significant change in terms of the volume flows. The left area describes the UC1 mode or the series connection R. The right area, on the other hand, describes the UC2 mode or the parallel connection P.

[0046] Between these two modes, a middle area with a multiplicity of intermediate positions of the valve 14 can be controlled in order to bring about a needs-based mixing of the coolant flows of the cooling circuits 4, 6 (mixing mode M=UC3). Analogously to what has been stated above, discrete intermediate positions can in principle be set in increments. As an alternative thereto, the intermediate positions can also be set infinitely variably or continuously over the entire middle area so as to enable even more precise control of the temperature both of the battery 10 and the electric motor 12.

[0047] With regard to the two proposed embodiments, the additional path 20 makes it possible, in a corresponding valve position of the 3/2-way valve 18 (according to the first embodiment) or in a corresponding valve position of the 5/3-way valve (according to the second embodiment), to set a fourth mode of the system (Use Case 4, for short: UC4=bypass mode B with reduction of the hydraulic resistance & maximum heat recovery), in which a hydraulic resistance is reduced and at the same time a maximum heat recovery for heating the battery 10 is made possible.

[0048] Via the path 22, however, in addition or as an alternative thereto, it is possible, in a corresponding valve position of the 3/2-way valve 18 (first embodiment) or of the 5/3-way valve (second embodiment), to set a fifth mode of the system (Use Case 5, for short: UC5=selective overheating protection), in which overheating of the battery 10 is avoided by cooling via the radiator 24.

[0049] The graph in FIG. 5 illustrates the volume flows VS that can be set with respect to the 3/2-way valve of the first embodiment, whereas the graph in FIG. 7 illustrates the volume flows VS that can be set with respect to the 5/3-way valve of the second embodiment. In FIG. 5, the input b.sup.I and the two outputs a.sub.I, c.sup.I of the 3/2-way valve are seen. In FIG. 7, however, the volume flows VS through the inputs a, e of the 5/3-way valve are described, specifically based on the volume flow VS through the inlet b.sup.I to the junction KP downstream of the electric motor 12, at which junction the bypass path 20 and the radiator path 22 originate.

[0050] The graph in FIG. 7 is compressed in relation to the graph in FIG. 5. This is because, in the case of the second embodiment, there is no second, separate multi-way valve which can be switched independently of the first multi-way valve. In this respect, there is to a certain extent no degree of freedom of adjustment with regard to FIG. 7, and therefore closing input a is accompanied by opening input e, and vice versa.

[0051] Although exemplary embodiments are explained in the above description, it should be noted that numerous modifications are possible. It should be noted, furthermore, that the exemplary embodiments are merely examples which are in no way intended to limit the scope of protection, the applications, and the design. Instead, the above description gives a person skilled in the art a guideline for the implementation of at least one exemplary embodiment, wherein various changes may be made, especially with regard to the function and arrangement of the integral parts described, without departing from the scope of protection as it is apparent from the claims and combinations of features equivalent thereto.