Patent ID: 12199257

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

The thermal management system2according toFIG.1andFIG.2illustrates a first cooling circuit4for a battery10and a second cooling circuit6for an electric motor12for driving the vehicle, as well as a refrigerant circuit8of 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 circuits4,6,8merge to a certain extent with one another. The respective fluid is conveyed in the two cooling circuits4,6by a dedicated electric pump16,17.

The electric motor12and the power electronics LE should be operated at a coolant or cooling water temperature of approx. 85° C. The battery10or 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 battery10. The temperature of the battery10or of the individual battery cells themselves can definitely exceed the 40° C. temperature threshold. The two cooling circuits4,6are therefore required. The two cooling circuits4,6have to be able to both absorb and dissipate heat. While the battery cooling circuit4is cooled via a heat exchanger Ch (cf.FIG.1; see chiller, for short: Ch) in relation to the refrigerant circuit8, the electric motor cooling circuit6can be cooled in relation to the environment via a radiator24and in relation to the battery cooling circuit4via a multi-way valve14described below (Coolant Flow Control Valve, for short: CFCV), wherein the multi-way valve14is an interface between the battery cooling circuit4and the electric motor cooling circuit6. The battery cooling circuit4can also be cooled via the radiator24in an appropriate valve position of the multi-way valve14. However, since the battery coolant should not exceed a temperature of 40° C., the cooling via the radiator24is usually insufficient, and therefore heat has to be dissipated via the heat exchanger Ch. In addition to the electric motor12and the power electronics LE, a charger (for short: C) is also to be cooled in the electric motor cooling circuit6. A temperature sensor CTS is provided for controlling the respective cooling circuit4,6. A resistance heater PTC is also provided in the battery cooling circuit4. The electric motor12is either water-cooled or oil-cooled. In the latter case, a corresponding oil cooling circuit of the electric motor12is connected to the motor cooling circuit6by a heat exchanger (not shown here).

The thermal management system2can be operated in different modes by means of the multi-way valve14. The multi-way valve14here is part of what is referred to as an actuator unit or cooling water control valve unit, which as such also comprises a drive unit with an electric servomotor and a control unit for controlling the electric servomotor.

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 valve14, the cooling circuit4can be connected in series with the cooling circuit6. With respect to the multi-way valve14, coolant flows via an inlet or input a from the cooling circuit6via the outlet or output c into the cooling circuit4and finally via the inlet or input d from the cooling circuit4via the outlet or output b back into the cooling circuit6.

This series connection causes the battery cooling circuit4to heat rapidly, utilizing the waste heat from the electric motor12and the power electronics LE. The electric motor cooling circuit6thus also has the function of a heating circuit.

In a second mode of the system (Use Case 2, for short: UC2=parallel connection P with overheating protection) and in a second valve position of the multi-way valve14, the cooling circuit4can be connected parallel to the cooling circuit6, such that the two cooling circuits4,6are fluidically separated from each other. This separation protects the battery10from overheating.

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 valve14is switched to an intermediate position—i.e. a third valve position—in which the coolant flows of the two cooling circuits4,6are mixed with each other as needed.

Such a mixing mode allows both the temperature of the battery10and the temperature of the electric motor12to be controlled more precisely. There are no high pressure and temperature jumps in the two cooling circuits4,6, since there is no switching between the series connection mode R and the parallel connection mode.

In a first embodiment (cf.FIG.1andFIG.2), the multi-way valve14is 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 circuit6downstream of the electric motor12, a further multi-way valve18in the form of a 3/2-way valve is also provided, the outlet or output of which a1is fluidically connected to the inlet or input a of the 4/2-way valve14. The multi-way valve18is also part of a further actuator unit or cooling water control valve unit, which as such also comprises a drive unit with an electric servomotor and a control unit for controlling the electric servomotor.

By the 3/2-way valve18, a coolant flow can optionally be conducted via a path22with a radiator24and/or via a path20parallel thereto—bypass path20—for bypassing the radiator24.

FIG.4illustrates 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.

Between these two modes, a middle area with a multiplicity of intermediate positions of the valve14can be controlled in order to bring about a needs-based mixing of the coolant flows of the cooling circuits4,6(mixing mode M=UC3). In principle, discrete intermediate positions can be set here 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 battery10and the electric motor12.

In an alternative second embodiment (cf.FIG.3), the multi-way valve14is designed 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 inFIG.3should also be imagined here, which inlet or input as such is fluidically connected via a bypass path20to a junction KP (or the outlet a1thereof) downstream of the electric motor12, wherein both the bypass path20and a path22parallel thereto with a radiator24originate from the junction KP. The radiator path22fluidically connects the junction KP (or the outlet c1thereof) to the inlet or input a of the 5/3-way valve.

FIG.6illustrates—analogously toFIG.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.

Between these two modes, a middle area with a multiplicity of intermediate positions of the valve14can be controlled in order to bring about a needs-based mixing of the coolant flows of the cooling circuits4,6(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 in order to enable even more precise control of the temperature both of the battery10and the electric motor12.

With regard to the two proposed embodiments, the additional path20makes it possible, in a corresponding valve position of the 3/2-way valve18(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 battery10is made possible.

Via the path22, however, in addition or as an alternative thereto, it is possible, in a corresponding valve position of the 3/2-way valve18(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 battery10is avoided by cooling via the radiator24.

The graph inFIG.5illustrates the volume flows VS that can be set with respect to the 3/2-way valve of the first embodiment, whereas the graph inFIG.7illustrates the volume flows VS that can be set with respect to the 5/3-way valve of the second embodiment. InFIG.5, the input b′ and the two outputs a1, c1of the 3/2-way valve are seen. InFIG.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 b1to the junction KP downstream of the electric motor12, at which junction the bypass path20and the radiator path22originate.

The graph inFIG.7is compressed in relation to the graph inFIG.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 toFIG.7, and therefore closing input a is accompanied by opening input e, and vice versa.

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.

Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.