Coolant circuit for a motor vehicle having a four-way mixing valve, motor vehicle and method for operating a coolant circuit

Abstract

The invention relates to a coolant circuit (10) for a motor vehicle, to a motor vehicle and to a method for operating the coolant circuit (10). A cooling device (18) is provided for cooling a battery of the motor vehicle, and a pumping device (20) is provided for conveying the coolant. An electric heating device (22) and a chiller (24) are arranged in the coolant circuit (10). The chiller (24) can be operated as an evaporator of a refrigerant circuit of the motor vehicle (12). The coolant circuit (10) has a valve device (30) having two coolant inlets (32, 34) and two coolant outlets (36, 38). The valve device (30) can be operated in a first valve state in which the coolant conveyed by means of the pump device (20) enters the valve device (30) at one of the coolant inlets (32, 34) and exits the valve device (30) at one of the coolant outlets (36, 38). In the first valve state, the coolant can be conveyed through the cooling device (18) by means of the pump device (20), bypassing the heating device (22) and the chiller (24).

Description

[0001] Coolant circuit for a motor vehicle with a four-way mixing valve, motor vehicle and method for operating a coolant circuit

[0002] DESCRIPTION:

[0003] The invention relates to a coolant circuit for a motor vehicle, comprising a cooling device for cooling a battery of the motor vehicle, and comprising a pumping device by means of which coolant can be conveyed through the cooling device. An electric heating device through which the coolant can flow and a chiller through which the coolant can flow are arranged in the coolant circuit. The chiller can be operated as an evaporator of a refrigerant circuit of the motor vehicle. The coolant circuit has a valve device with two coolant inlets and two coolant outlets. Furthermore, the invention relates to a motor vehicle with such a coolant circuit and a method for operating a coolant circuit.

[0004] Motor vehicles designed as electric or hybrid vehicles today typically have a compression refrigeration machine or a refrigerant circuit, which can be used in air conditioning mode to cool the passenger compartment of the motor vehicle and in heat pump mode to heat the passenger compartment. Furthermore, a coolant circuit is usually provided for cooling and heating a battery of the motor vehicle, with a coolant being pumped through the coolant circuit by means of a pumping device.

[0005] To achieve efficient heating of the passenger compartment using a refrigerant circuit operating as a heat pump, heat sources such as the ambient air or heated coolant in the coolant circuit can be used. However, at very low ambient temperatures, it may be the case that insufficient heat energy from such heat sources is available for heat pump operation of the refrigerant circuit. In this case, it may be advisable to provide heat in the coolant circuit using an electric heater. This heat introduced into the coolant can then be used as a heat source in the heat pump operation of the refrigerant circuit.

[0006] Furthermore, it is possible to heat the coolant using the electric heating device integrated into the coolant circuit in order to bring the motor vehicle's battery to a desired operating temperature. Accordingly, supporting the heat pump function using the electric heating device can be considered a secondary function or functional extension of the electric heating device arranged in the coolant circuit.

[0007] DE 10 2021 207 249 A1 describes a thermal management system for a motor vehicle battery. The thermal management system can have a four-way valve, which, together with a pumping device, is arranged in a coolant circuit of the thermal management system. A battery, an electric auxiliary heater, and a chiller are also arranged in the coolant circuit. Depending on the switching position of the four-way valve and an additional switching valve, the pumping device can pump the coolant only through the battery and through the electric auxiliary heater, or through the battery, through the electric auxiliary heater, and through the chiller. If, in this thermal management system, coolant is only to flow through the battery to compensate for temperature differences within the battery, an additional pumping device of the thermal management system is activated.

[0008] This is complex. The thermal management system described in DE 10 2021 207 249 A1 therefore has potential for improvement. The object of the present invention is therefore to create a coolant circuit of the type mentioned above, by means of which an improved cooling function can be realized with minimal effort, as well as to provide a motor vehicle with such a coolant circuit and a corresponding method for operating a coolant circuit.

[0009] This object is achieved by a coolant circuit having the features of patent claim 1, a motor vehicle having the features of patent claim 9, and a method having the features of patent claim 10. Advantageous embodiments with expedient further developments of the invention are specified in the dependent patent claims and in the following description.

[0010] The coolant circuit according to the invention for a motor vehicle comprises a cooling device for cooling a battery of the motor vehicle. By means of a pump device of the coolant circuit, coolant can be conveyed through the cooling device. An electric heating device through which the coolant can flow and a chiller through which the coolant can flow are arranged in the coolant circuit. The chiller can be operated as an evaporator of a refrigerant circuit of the motor vehicle. Accordingly, the chiller is a heat exchanger through which the coolant can flow on the one hand and the refrigerant on the other. The coolant circuit has a valve device with two coolant inlets and two coolant outlets. The valve device can be operated in a first valve state.In the first valve state, the coolant conveyed or conveyable by the pump device enters the valve device at one of the coolant inlets and exits the valve device at one of the coolant outlets. In the first valve state of the valve device, the coolant can be conveyed through the cooling device by means of the pump device, bypassing both the electric heating device and the chiller. As a result, temperature differences within the battery can be very easily compensated for in the first valve state of the valve device. In this case, the pump device does not need to convey the coolant through the electric heating device or through the chiller. As a result, operation of the coolant circuit in the first valve state of the valve device is associated with a particularly low pressure loss. Accordingly, an improved cooling function can be achieved with very little effort using the coolant circuit.

[0011] Since in the first valve state of the valve device, neither the heating device nor the chiller are flowing through the coolant, the flow through the cooling device intended for cooling the battery can be achieved with a comparatively low pumping power of the pump device. This is advantageous for efficient operation of the coolant circuit.

[0012] Furthermore, the two coolant inlets and the two coolant outlets of the valve device arranged in the coolant circuit enable a plurality of different valve states of the valve device to be set, by means of which a plurality of cooling functions and / or temperature control functions can be realized in the coolant circuit.

[0013] Preferably, the cooling device designed to cool the battery is in contact with the battery to be cooled, allowing heat conduction. For example, the cooling device can comprise at least one heat sink through which the coolant can flow, to which heat can be transferred from the battery cells by heat conduction in order to cool the battery.

[0014] If ordinal numbers such as "first," "second," "third," and so on are used above or below in reference to a valve state, these ordinal numbers do not represent a ranking or sequence. Rather, the respective designation of the valve state with such an ordinal number merely serves to distinguish the valve states from one another. The same applies if ordinal numbers such as "first," "second," "third," and so on are used for other devices in the coolant circuit.

[0015] The valve device is preferably operable in a second valve state, in which the coolant that can be or is being pumped by means of the pump device enters the valve device at one of the coolant inlets and exits the valve device at one of the coolant outlets. In the second valve state of the valve device, the coolant can be pumped through the chiller and through the cooling device, bypassing the electric heating device. As a result, efficient cooling of the battery can be achieved by means of the chiller in that the cooling device is supplied with coolant, which also flows through the chiller. In the chiller, the coolant evaporating in the coolant circuit can absorb heat and thus extract heat from the coolant. In this way, particularly intensive cooling of the battery can be achieved by means of the cooling device.

[0016] In particular, in the second valve state, the coolant can be pumped by means of the pumping device, bypassing the electric heating device, from the valve device, first through the chiller and then through the cooling device. This facilitates easy integration of the chiller into the coolant circuit.

[0017] The valve device is preferably operable in a third valve state, in which the coolant that can be conveyed or is being conveyed by the pump device enters the valve device at one of the coolant inlets and exits the valve device at one of the coolant outlets. In the third valve state of the valve device, the coolant can be conveyed by the pump device, bypassing the chiller, through the cooling device and through the electric heating device. In this way, the temperature of the battery can be increased by means of the cooling device, which is then operated as a temperature control device. This is advantageous, for example, at low ambient temperatures in order to quickly bring the battery to a favorable operating temperature.When the battery is at operating temperature, it has a high capacity to provide electrical energy, for example, for a motor vehicle's electric drive system. This is advantageous.

[0018] In particular, in the third valve state of the valve device, the coolant can be conveyed by means of the pump device, bypassing the chiller, from the valve device, first through the cooling device and then through the electric heating device. This is advantageous with regard to a fluidically favorable integration of the electric heating device into the coolant circuit.

[0019] The valve device is preferably operable in a fourth valve state, in which the coolant that can be conveyed or is being conveyed by means of the pump device enters the valve device at one of the coolant inlets and exits the valve device at one of the coolant outlets. In the fourth valve state of the valve device, the coolant can be conveyed by means of the pump device, starting from the valve device, first through the chiller, then through the cooling device, and finally through the electric heating device. Accordingly, in this fourth valve state of the valve device, during operation of the coolant circuit, the chiller is supplied with the warmest coolant before the coolant reaches the cooling device, which in this fourth valve state of the valve device serves to heat the battery.

[0020] This allows the vehicle's refrigerant circuit to be put into operation as a heat pump very early on. To operate the refrigerant circuit as a heat pump, it is necessary to ensure that the chiller is at a certain minimum temperature. This ensures stable operation of the refrigerant circuit. By supplying the particularly warm coolant to the chiller in the fourth valve state of the valve device during operation of the coolant circuit—namely, the coolant heated by the electric heater—this minimum temperature can be set very quickly on the chiller, which allows the refrigerant circuit to be activated or commissioned as a heat pump.

[0021] For example, even at ambient temperatures of approximately -20°C, the refrigerant circuit can be operated as a heat pump if the heated coolant is first fed to the chiller via the electric heater. This allows the passenger compartment of a vehicle to be heated very quickly, even at such low ambient temperatures, using the refrigerant circuit operating as a heat pump. This leads to increased comfort for the vehicle's passenger compartment.

[0022] Preferably, the valve device is operable in a fifth valve state, in which the coolant conveyed or conveyable by the pump device enters the valve device at one of the coolant inlets and exits the valve device at both coolant outlets. In the fifth valve state of the valve device, the coolant can be conveyed by means of the pump device, starting from the valve device, both to the chiller and to the cooling device. Furthermore, the coolant coming from the cooling device can be conveyed through the electric heating device by means of the pump device before entering the valve device.

[0023] Such an operating state of the coolant circuit is particularly advantageous in order to ensure stable operation of the refrigerant circuit. This is because if the entire volume flow of coolant delivered by the pumping device is delivered both through the cooling device of the battery and through the chiller, this can lead to an undesirably high temperature level of the coolant at the chiller. This applies in particular if the volume flow to be provided by the pumping device, which is to be delivered through the cooling device for the battery, is based on the temperature control requirements of the battery. In this case in particular, it is therefore advantageous if, by dividing the volume flow at the valve device by operating the valve device in the fifth valve state, not the full volume flow delivered by the pumping device flows through the chiller, but only a reduced volume flow.

[0024] This is based on the realization that a specific average temperature must be set at the chiller for proper and stable operation of the refrigerant circuit. For a given coolant temperature, a lower average temperature can be set at the chiller by reducing the volume flow of coolant pumped through the chiller. Therefore, it is advantageous if the valve device can be operated in the fifth valve state.

[0025] When the valve device is operated in the respective valve state, it can advantageously be ensured that the electric heater is flowed through unidirectionally, i.e. always in the same direction, provided that flow through the electric heater is intended at all in the respective operating state of the coolant circuit. This is particularly advantageous with regard to the arrangement of the electric heater in the motor vehicle. This is because it allows a great deal of freedom with regard to the type of arrangement of the electric heater in the motor vehicle. In particular, this avoids the electric heater having to be installed in a specific installation position. In addition, this makes it easy to ensure that the electric heater can be easily vented. Furthermore, particularly robust operation of the electric heater is guaranteed.

[0026] Furthermore, the valve device, designed as a four-way valve, enables the heat provided by the electric heating device to be distributed between both the cooling device intended for cooling or heating the battery and the chiller. Heating the chiller can support the operation of the refrigerant circuit as a heat pump in certain operating cases. This is particularly true for operating cases in which not enough heat energy can be obtained from other sources to set a certain minimum temperature at the chiller. Therefore, it is advantageous for the coolant circuit to have the electric heating device and the valve device with two coolant inlets and two coolant outlets.

[0027] Preferably, the valve device has a closure means that can be moved into a plurality of positions in the fifth valve state. In the respective positions, different partial flows of the coolant can be conveyed from the valve device to both the chiller and the cooling device by operating the pump device. This allows the volume flow to be supplied to the chiller to be metered very precisely. This is advantageous with regard to stable operation of the chiller as an evaporator in the refrigerant circuit of the motor vehicle.

[0028] Preferably, the electric heating device, the cooling device, the valve device, and the pumping device are arranged in a first sub-branch of the coolant circuit. The chiller and a further pumping device of the coolant circuit are arranged in a second sub-branch of the coolant circuit. Furthermore, the coolant can be conveyed through the second sub-branch by operating the further pumping device, regardless of whether the coolant flows through the first sub-branch.Such a coolant circuit design is advantageous, for example, when motor vehicle components arranged in the second sub-branch of the coolant circuit, such as an electric drive device and / or power electronics and / or at least one electrical converter or power inverter and / or at least one control unit or the like, emit heat, which can be transferred to the refrigerant evaporating in the chiller during heat pump operation of the motor vehicle's refrigerant circuit. Efficient operation of the refrigerant circuit as a heat pump is then possible without the need for heat from the electric heating device.

[0029] Heat pump operation needs to be contributed. This is advantageous.

[0030] Nevertheless, by operating the pumping device arranged in the first sub-branch, heat provided by the electric heating device can be used to heat the battery via the cooling device, which in this case serves as a heat source for the battery and can therefore also be generally referred to as a temperature control device.

[0031] Preferably, a first bypass line is arranged in the first sub-branch, via which the coolant conveyed by the pumping device can be conveyed through the cooling device, bypassing the electric heating device and the valve device. This allows temperature differences within the battery to be compensated for with a particularly low pressure loss and thus a particularly low delivery rate or pumping capacity of the pumping device. Temperature differences within the battery can occur, for example, due to different operating states of the respective battery cells of the battery.

[0032] Additionally or alternatively, a second bypass line can be arranged in the second sub-branch, via which the coolant conveyed by the pumping device can be conveyed through a section of the second sub-branch, bypassing the further pumping device. This allows for very efficient operation of the pumping device, in which the pumping device does not need to generate a particularly high flow rate or pumping power.

[0033] The motor vehicle according to the invention has a coolant circuit according to the invention and a battery. Here, the battery is designed to supply at least one electric drive device of the motor vehicle with electrical energy. In the motor vehicle, the coolant circuit can advantageously be used to cool and heat the battery. The battery can be designed, in particular, as a high-voltage battery or high-voltage storage device, which has a nominal voltage of more than 60 volts and preferably of up to several hundred volts. If the electrical heating device of the coolant circuit is supplied with electrical energy by the high-voltage battery, the electrical heating device designed as an auxiliary heating device can be referred to as a high-voltage heater.

[0034] Preferably, the at least one electric drive device of the motor vehicle is designed to effect or at least assist the movement of the motor vehicle. Accordingly, the motor vehicle can be designed, in particular, as an electric vehicle or a hybrid vehicle.

[0035] In such a motor vehicle, cooling and heating the battery is particularly advantageous so that it can provide the desired amount of electrical energy for the motor vehicle's electric drive system. Furthermore, when the motor vehicle is designed as an electric vehicle or hybrid vehicle, it is particularly advantageous to operate the refrigerant circuit, in which the chiller is integrated as well as the coolant circuit, either as an air conditioning system or as a heat pump.

[0036] In the method according to the invention for operating a coolant circuit of a motor vehicle, the coolant circuit has a cooling device for cooling a battery of the motor vehicle and a pumping device. Coolant is pumped through the cooling device by means of the pumping device. An electric heating device through which the coolant can flow and a chiller through which the coolant can flow are arranged in the coolant circuit, wherein the chiller can be operated as an evaporator of a refrigerant circuit of the motor vehicle. The coolant circuit has a valve device with two coolant inlets and two coolant outlets. The valve device is operated in a first valve state in which the coolant pumped by means of the pumping device enters the valve device at one of the coolant inlets and exits the valve device at one of the coolant outlets.In the first valve state of the valve device, the coolant is pumped through the cooling device by means of the pump device, bypassing both the electric heating device and the chiller.

[0037] This allows for an improved cooling function, which compensates for temperature differences within the battery, to be implemented with particularly low effort. Because the pumping device does not need to pump the coolant through the electric heater or the chiller of the coolant circuit, the pressure loss in the coolant circuit during operation can be kept particularly low.

[0038] The advantages and preferred embodiments described for the coolant circuit according to the invention also apply to the motor vehicle according to the invention and to the method according to the invention and vice versa.

[0039] The invention therefore also includes further developments of the method according to the invention that have features already described in connection with the further developments of the coolant circuit according to the invention and the motor vehicle according to the invention. For this reason, the corresponding further developments of the method according to the invention are not described again here.

[0040] The motor vehicle according to the invention is preferably designed as a motor vehicle, in particular as a passenger car or truck, or as a passenger bus.

[0041] The invention also encompasses combinations of the features of the described embodiments. The invention therefore also encompasses implementations that each comprise a combination of the features of several of the described embodiments, unless the embodiments are described as mutually exclusive.

[0042] Exemplary embodiments of the invention are described below. Shown are:

[0043] Fig. 1 shows schematically and in detail a coolant circuit for a motor vehicle, which has a valve device operable in several valve states;

[0044] Fig. 2 shows the coolant circuit with the valve device in a first valve state, in which coolant flows through a cooling device provided for cooling a battery of the motor vehicle, an electric heating device and a chiller being bypassed;

[0045] Fig. 3 shows the coolant circuit according to Fig. 1 with the valve device operated in a second valve state, in which a cooling operation of the battery is realized;

[0046] Fig. 4 shows the coolant circuit according to Fig. 1, wherein the valve device is operated in a third valve state in which the battery is heated;

[0047] Fig. 5 shows the coolant circuit according to Fig. 1 , wherein the valve device is operated in a fourth valve state in which both the chiller and the battery are heated by means of heat provided by the electrical heating device;

[0048] Fig. 6 shows the coolant circuit according to Fig. 1, wherein the valve device is operated in a fifth valve state, in which a coolant flow leaving the valve device via two coolant outlets is directed to the battery-associated coolant flow.

[0049] cooling device and distributed to the chiller; and

[0050] Fig. 7 shows a highly schematic view of the motor vehicle with the battery and an electric drive device for moving the motor vehicle.

[0051] Fig. 1 schematically shows a coolant circuit 10 of a motor vehicle 12 (see Fig. 7), not shown in detail in Fig. 1. The motor vehicle 12 has a battery 14, by means of which at least one electric drive device 16 of the motor vehicle 12 can be supplied with electrical energy. The at least one electric drive device 16 of the motor vehicle 12 (see Fig. 7) is designed to propel the motor vehicle 12 or at least to assist the propulsion of the motor vehicle 12. Accordingly, the motor vehicle 12 can be designed as an electric vehicle or as a hybrid vehicle.

[0052] It is useful to cool the battery 14 if heat is to be dissipated from battery cells (not shown) of the battery 14. Furthermore, it is advantageous to heat the battery 14 in order to bring the battery 14 to a desired operating temperature at which the battery 14 can efficiently provide electrical energy for the at least one electric drive device 16.

[0053] For this purpose of cooling and heating the battery 14, a cooling device 18 is arranged in the coolant circuit 10. The cooling device 18 can also be referred to as a temperature control device. In the cooling case, the cooling device 18 serves to cool the battery 14, and in the heating case, heat is introduced into the battery 14 via the cooling device 18. To simplify the terminology, however, this temperature control device will be referred to simply as the cooling device 18 hereinafter. The cooling device 18 is preferably arranged on the battery 14. This allows waste heat from the battery cells of the battery 14 to be introduced into the cooling device 18 very effectively via thermal conduction, or to heat the battery 14, heat can be introduced very directly via thermal conduction into the battery 14 by means of the cooling device 18.

[0054] A first pumping device 20 is arranged in the coolant circuit 10, by means of which coolant can be pumped through the cooling device 18. Furthermore, an electric heating device 22 through which the coolant flows is arranged in the coolant circuit 10. Because the electric heating device 22 is supplied with electrical energy by the battery 14, which is preferably designed as a high-voltage battery, the electric heating device 22 can be referred to as a high-voltage heater.

[0055] Furthermore, a chiller 24 is arranged in the coolant circuit 10. The chiller 24 is a heat exchanger through which the coolant flows on the one hand and a refrigerant on the other. Accordingly, the chiller 24 is integrated into both the coolant circuit 10 and a refrigerant circuit 26, which is shown only schematically and in detail in Fig. 1.

[0056] The chiller 24 can be operated as an evaporator of the refrigerant circuit 26. Accordingly, the chiller 24 can be pressurized with refrigerant, which is expanded by means of an expansion device (not shown here) arranged upstream of the chiller 24. The expanded refrigerant can absorb heat from the coolant. The refrigerant is then fed to a compressor (not shown) of the refrigerant circuit 26. From the compressor, the compressed and therefore hot refrigerant reaches a heating register (not shown), which is designed as a refrigerant-to-air heat exchanger. The air passing over the heating register can be introduced into a passenger compartment 28 (see Fig. 7) of the motor vehicle 12 to heat the passenger compartment 28.

[0057] Consequently, the refrigerant circuit 26 can be operated as a heat pump when heat is required in the passenger compartment 28 of the motor vehicle 12. Furthermore, it is preferably possible to operate the refrigerant circuit 26 as an air conditioning system, whereby the air introduced into the passenger compartment 28 is cooled.

[0058] A valve device 30 is arranged in the coolant circuit 10, which, according to Fig. 1, is designed as a four-way valve. Accordingly, the valve device 30 has exactly two coolant inlets 32, 34 and exactly two coolant outlets 36, 38. Respective lines of the coolant circuit 10 are connected to both the two coolant inlets 32, 34 and the two coolant outlets 36, 38 of the valve device 30.

[0059] Fig. 1 schematically shows a closure means 40 of the valve device 30, which makes it possible to open at least one of the coolant inlets 32, 34 and at least one of the coolant outlets 36, 38 in respective valve states of the valve device 30. Furthermore, the closure means 40 preferably makes it possible to open both coolant inlets 32, 34 and only one of the coolant outlets 36, 38 at the same time.

[0060] In addition, the closure means 40 preferably makes it possible to open only one of the coolant inlets 32, 34 and simultaneously both coolant outlets 36, 38. In this case, a volume flow of the coolant to be distributed between the respective coolant outlets 36, 38 can preferably be adjusted as required.

[0061] Different valve states of the valve device 30 are explained below, in particular with reference to possible or advantageous connection options, which are shown in Fig. 2 to Fig. 6. In preferred operating states of the coolant circuit 10, the flow directions of the coolant through the coolant circuit 10 are illustrated in the figures by respective arrowheads indicated on respective lines of the coolant circuit 10. According to Fig. 2, the valve device 30 can be operated in a first valve state, in which the coolant conveyed by the pump device 20 enters the valve device 30 at one of the coolant inlets 32, 34, for example at the first coolant inlet 32, and exits the valve device 30 at one of the coolant outlets 36, 38, for example at the first coolant outlet 36. The corresponding adjustment position of the valve or the valve device 30 is shown in Fig.2 is illustrated by a further schematic representation in which there is no fluidic connection between the second coolant inlet 34 and the second coolant outlet 38.

[0062] In the first valve state of the valve device 30, the coolant is pumped through the cooling device 18 by means of the pump device 20, bypassing both the electric heating device 22 and the chiller 24. Accordingly, the battery 14 is connected neither to a heat source nor to a heat sink. However, pumping the coolant through the cooling device 18 results in temperature differences within the battery 14 being equalized. Temperature differences within the battery 14 may be due to the fact that the battery cells (not shown) of the battery 14 have different temperatures from one another.

[0063] Furthermore, the battery cells of battery 14 can be arranged in respective battery modules, wherein battery 14 can comprise a plurality of such battery modules. When the coolant flows through the cooling device 18 according to the operating state of coolant circuit 10 shown in Fig. 2, temperature differences between such battery modules of battery 14 can also be well compensated.

[0064] According to Fig. 3, the valve device 30 can be operated in a second valve state, in which the coolant conveyed by the pump device 20 enters the valve device 30 at one of the coolant inlets 32, 34, for example, at the first coolant inlet 32. The coolant exits the valve device 30 at one of the coolant outlets 36, 38, for example, at the second coolant outlet 38. In the second valve state of the valve device 30, the coolant is conveyed by the pump device 20, bypassing the electric heating device 22, through the chiller 24 and through the cooling device 18. The coolant preferably flows from the valve device 30, first through the chiller 24 and then via a bypass line 42 back to the pump device 20, and from the pump device 20 further to the cooling device 18.In this case, the bypass line 42 serves to bypass a further or second pumping device 44 of the coolant circuit 10, the function of which will be explained in more detail later. A first check valve 52 arranged in the bypass line 42 ensures, as shown in Fig. 3, that the coolant can only flow through the bypass line 42 in one direction.

[0065] In the second valve state of the valve device 30, the battery 14 can be cooled by the cooling device 18, which is supplied with the coolant coming from the chiller 24 and thus cooled. Accordingly, the battery 14 is connected to the chiller 24.

[0066] According to Fig. 4, the valve device 30 can be operated in a third valve state, in which the coolant conveyed by the pump device 20 enters the valve device 30 at one of the coolant inlets 32, 34, for example, at the second coolant inlet 34. At one of the coolant outlets 36, 38, for example, at the first coolant outlet 36, the coolant exits the valve device again in the third valve state of the valve device 30.

[0067] In the third valve state of the valve device 30, the coolant is pumped through the cooling device 18 and through the electric heating device 22 by means of the pump device 20, bypassing the chiller 24. In particular, the coolant is pumped from the valve device 30, first via the pump device 20 to the cooling device 18, then through the cooling device 18, and finally through the electric heating device 22 when the valve device 30 is in the third valve state. In the third valve state, the valve device 30 enables heating of the battery by supplying the cooling device 18 with the coolant, which is heated by the electric heating device 22.

[0068] In the operating state of the coolant circuit 10 shown in Fig. 4, a first sub-branch 46 of the coolant circuit 10 is decoupled from a second sub-branch 48 of the coolant circuit 10. The electric heating device 22, the cooling device 18, the valve device 30, and the pumping device 20 or first pumping device 20 are arranged in the first sub-branch 46. In contrast, the chiller 24 and the second pumping device 44 are arranged in the second sub-branch 48 of the coolant circuit 10. By operating the second pumping device 44, the coolant can thus be conveyed through the second sub-branch 48 without the need for flow through the first sub-branch 46 of the coolant circuit 10.

[0069] Further components 50 are arranged in the second sub-branch 48, the cooling and / or heating of which may be desirable. The components 50 can be supplied with coolant by means of at least one heat exchanger integrated into the second sub-branch 48. The at least one heat exchanger can be configured to dissipate heat from the coolant and / or to absorb heat from the coolant.

[0070] For example, the components 50 may comprise at least one heat exchanger for cooling the electric drive device 16 (see Fig. 7) of the motor vehicle 12 and / or at least one heat exchanger for cooling at least one power electronics unit and / or at least one electrical converter or power converter and / or at least one control unit of the motor vehicle 12. Additionally or alternatively, the components 50 may comprise a heat exchanger which is designed as an air-cooled heat exchanger and can be cooled, in particular, by ambient air. For reasons of simplicity, such a coolant-to-air heat exchanger is not shown in detail in the second sub-branch 48 of the coolant circuit 10.

[0071] In particular, at least one further valve device (not shown here) can be arranged in the second sub-branch 48 of the coolant circuit 10, by means of which, during operation of the second pump device 44, corresponding coolant flows through the components 50, shown only schematically here, and / or the coolant-to-air heat exchanger (not shown) can be adjusted as needed. However, the corresponding operating modes need not be explained in more detail here.

[0072] The use of the electric heating device 22 to provide heat for the chiller 24 is particularly advantageous when the components 50 arranged in the second sub-branch 48 are not able to provide sufficient heat for the chiller 24.

[0073] For example, in the operating state of the coolant circuit 10 shown in Fig. 2, the first sub-branch 46 can be operated decoupled from the second sub-branch 48. In particular, in this operating state of the coolant circuit 10, a further ambient line 54 can be used, which is arranged in the first sub-branch 46.

[0074] Via this additional ambient line 54, the coolant that can be pumped by means of the pumping device 20 or the first pumping device 20 can be pumped through the cooling device 18, bypassing the electric heating device 22 and the valve device 30. This enables operation of the coolant circuit 10 with a particularly low pressure loss if only temperature differences between the individual battery cells of the battery 14 and / or between individual battery modules of the battery 14 are to be compensated.

[0075] According to Fig. 5, the valve device 30 can be operated in a fourth valve state, in which the coolant conveyed by the pump device 20 enters the valve device 30 at one of the coolant inlets 32, 34, for example, at the second coolant inlet 34. The coolant exits the valve device 30 again at one of the two coolant outlets 36, 38, for example, at the second coolant outlet 38.

[0076] In this fourth valve state of the valve device 30, the coolant is pumped by means of the pump device 20, starting from the valve device 30, first through the chiller 24 and then via the bypass line 42 back to the pump 20.

[0077] From the first pump or first pumping device 20, the coolant then first flows into the cooling device 18 and then through the electric heating device 22 back to the valve device 30. In this operating state of the valve device 30, the chiller 24 is supplied with the coolant having the highest temperature level within the coolant circuit 10. Consequently, the chiller 24 can be brought very quickly to a desired minimum temperature, which allows for particularly trouble-free and robust operation of the refrigerant circuit 26.

[0078] In this way, the heat pump operation of the refrigerant circuit 26 can be carried out even at very low ambient temperatures. Accordingly, the passenger compartment 28 of the motor vehicle 12 can be supplied with warm air very quickly, so that a comfortable temperature is quickly provided for the occupants of the motor vehicle 12 in the passenger compartment 28.

[0079] The coolant, which is slightly less warm after flowing through the chiller 24, can continue to be used to transfer heat to the battery 14 in the cooling device 18. In the valve state of the valve device 30 shown in Fig. 5, both the battery 14 and the chiller 24 are connected to the electric heating device 22, so that both the chiller 24 and the battery 14 can be heated.

[0080] According to Fig. 6, the valve device 30 is operable in the fifth valve state, in which the coolant conveyed by the pump device 20 enters the valve device 30 at one of the coolant inlets 32, 34, for example, at the second coolant inlet 34. However, here the coolant simultaneously exits the valve device 30 at both coolant outlets 36, 38.

[0081] The coolant exiting the first coolant outlet 36 reaches a branching point 56 of the first sub-branch 46 of the coolant circuit 10. At this branching point 56, a first sub-flow of the coolant branches off to the pumping device 20 and then to the cooling device 18. A second sub-flow can continue from the branching point 56 via a connecting line 58 into the second sub-branch 48 of the coolant circuit 10. In the second sub-branch 48, the coolant coming from the connecting line 58 can reach the chiller 24.

[0082] The coolant exiting the valve device 30 at the second coolant outlet 38 can also be introduced into the second sub-branch 48 of the coolant circuit 10 via a further connecting line 60. Preferably, a second check valve 62 prevents coolant introduced into the second sub-branch 48 via the second connecting line 60 from reaching the first connecting line 58.

[0083] Accordingly, in this case, the second check valve 62 is arranged between a junction point 64, at which the second connecting line 60 opens into the second sub-branch 48, and the first connecting line 58. The coolant coming from the second connecting line 60 therefore flows from the junction point 64 toward the chiller 24.

[0084] In the fifth valve state of the valve device 30 shown in Fig. 6, the heat provided by the electric heating device 22, which enters the valve device 30, for example, at the second coolant inlet 34, is distributed to the cooling device 18 and the chiller 24. Accordingly, both the battery 14 and the chiller 24 can be heated or supplied with heat by means of the heat provided by the electric heating device 22.

[0085] By appropriately adjusting the closure means 40 (see Fig. 1) of the valve device 30, it can preferably be ensured in the present case that the volume flow of the coolant via the chiller 24 is lower than the volume flow of coolant which is guided via the cooling device 18.

[0086] In a manner analogous to that described for the heating case with reference to Fig. 6, in the cooling case shown in Fig. 3, the coolant introduced into the valve device 30 via the first coolant inlet 32 ​​can be distributed to the cooling device 18 and the chiller 24 via both coolant outlets 36, 38. Here, too, it can be ensured that the volume flow of coolant at the chiller 24 is not too large, so that the chiller 24 is not overloaded with regard to providing cooling capacity.

[0087] The valve device 30 designed as a four-way valve thus enables the realization of a plurality of cooling functions and / or heating functions in the coolant circuit 10. In this case, it can always be ensured that the chiller 24 is operated in an operating state which allows stable operation of the refrigerant circuit 26.

[0088] As can be seen from the figures, it is advantageously ensured in this case that the coolant flows through the electric heating device 22 in the same direction in all described valve states of the valve device 30. This unidirectional flow through the heating device 22 is particularly advantageous with regard to a favorable and simple arrangement of the heating device 22 in the motor vehicle 12.

[0089] Furthermore, in the present case, the electric heating device 22 is arranged such that, in the combined heating case, in which the heating device 22 supports the heat pump on the one hand and the battery 14 is to be heated on the other, the coolant first flows through the chiller 24 and then through the cooling device 18 assigned to the battery 14. This is particularly advantageous with regard to rapid heating of the passenger compartment 28 during heat pump operation of the refrigerant circuit 26.

[0090] Overall, the examples show how an improved cooling circuit or coolant circuit 10 can be provided for a motor vehicle 12 with heat pump functionality, in particular one designed as a battery-electric vehicle.

Claims

PATENT CLAIMS:

1. A coolant circuit (10) for a motor vehicle (12), comprising a cooling device (18) for cooling a battery (14) of the motor vehicle (12), and comprising a pumping device (20) by means of which coolant can be conveyed through the cooling device (18), wherein an electric heating device (22) through which the coolant can flow and a chiller (24) through which the coolant can flow are arranged in the coolant circuit (10), wherein the chiller (24) can be operated as an evaporator of a refrigerant circuit (26) of the motor vehicle (12), and wherein the coolant circuit (10) has a valve device (30) with two coolant inlets (32, 34) and with two coolant outlets (36, 38), characterized in that the valve device (30) is operable in a first valve state, in which the coolant conveyed by means of the pumping device (20) enters the valve device at one of the coolant inlets (32, 34). (30) and at one of the coolant outlets (36,38) exits the valve device (30), wherein in the first valve state of the valve device (30) the coolant can be conveyed through the cooling device (18) by means of the pump device (20), bypassing both the electric heating device (22) and the chiller (24).

2. Coolant circuit (10) according to claim 1, characterized in that the valve device (30) is operable in a second valve state, in which the coolant conveyed by means of the pump device (20) enters the valve device (30) at one of the coolant inlets (32, 34) and exits the valve device (30) at one of the coolant outlets (36, 38), wherein in the second valve state of the valve device (30), the coolant can be conveyed by means of the pump device (20) bypassing the electrical heating device (22) through the chiller (24) and through the cooling device (18), in particular starting from the valve device (30) first through the chiller (24) and then through the cooling device (18).

3. Coolant circuit (10) according to one of the preceding claims, characterized in that the valve device (30) is operable in a third valve state, in which the coolant conveyed by means of the pump device (20) enters the valve device (30) at one of the coolant inlets (32, 34) and exits the valve device (30) at one of the coolant outlets (36, 38), wherein in the third valve state of the valve device (30), the coolant can be conveyed by means of the pump device (20), bypassing the chiller (24), through the cooling device (18) and through the electric heating device (22), in particular starting from the valve device (30), firstly through the cooling device (18) and then through the electric heating device (22).

4. Coolant circuit (10) according to one of the preceding claims, characterized in that the valve device (30) is operable in a fourth valve state, in which the coolant conveyed by means of the pump device (20) enters the valve device (30) at one of the coolant inlets (32, 34) and exits the valve device (30) at one of the coolant outlets (36, 38), wherein in the fourth valve state of the valve device (30), the coolant can be conveyed by means of the pump device (20), starting from the valve device (30), first through the chiller (24), then through the cooling device (18) and subsequently through the electric heating device (22).

5. Coolant circuit (10) according to one of the preceding claims, characterized in that the valve device (30) is operable in a fifth valve state, in which the coolant conveyed by means of the pump device (20) is fed into the valve device (30) at one of the coolant inlets (32, 34). enters and exits the valve device (30) at both coolant outlets (36, 38), wherein in the fifth valve state of the valve device (30) the coolant can be conveyed by means of the pump device (20) starting from the valve device (30) both to the chiller (24) and to the cooling device (18), and wherein the coolant coming from the cooling device (18) can be conveyed by means of the pump device (20) through the electrical heating device (22) before entering the valve device (30).

6. Coolant circuit (10) according to claim 5, characterized in that the valve device (30) has a closure means (40) which, in the fifth valve state, is movable into a plurality of positions in which different partial flows of the coolant can be conveyed by operating the pump device (20) from the valve device (30) both to the chiller (24) and to the cooling device (18).

7. Coolant circuit (10) according to one of the preceding claims, characterized in that the electrical heating device (22), the cooling device (18), the valve device (30) and the pumping device (20) are arranged in a first partial branch (46) of the coolant circuit (10), wherein the chiller (24) and a further pumping device (44) of the coolant circuit (10) are arranged in a second partial branch (48) of the coolant circuit (10), wherein the coolant can be conveyed through the second partial branch (48) by operating the further pumping device (44) independently of flow through the first partial branch (46).

8. Coolant circuit (10) according to claim 7, characterized in that a first bypass line (54) is arranged in the first partial branch (46), via which the coolant (54) conveyable coolant can be conveyed through the cooling device (18), bypassing the electrical heating device (22) and the valve device (30), and / or a second bypass line (42) is arranged in the second partial branch (48), via which the coolant that can be conveyed by means of the pumping device (20) can be conveyed through a section of the second partial branch (48), bypassing the further pumping device (44).

9. Motor vehicle (12) with a coolant circuit (10) according to one of the preceding claims, and with a battery (14), wherein the battery (14) is designed to supply at least one electric drive device (16) of the motor vehicle (12) with electrical energy, and wherein the at least one electric drive device (16) is designed to cause or at least assist movement of the motor vehicle (12).

10. A method for operating a coolant circuit (10) of a motor vehicle (12), wherein the coolant circuit (10) has a cooling device (18) for cooling a battery (14) of the motor vehicle (12) and a pumping device (20) by means of which coolant is conveyed through the cooling device (18), wherein an electrical heating device (22) through which the coolant can flow and a chiller (24) through which the coolant can flow are arranged in the coolant circuit (10), wherein the chiller (24) can be operated as an evaporator of a refrigerant circuit (26) of the motor vehicle (12), and wherein the coolant circuit (10) has a valve device (30) with two coolant inlets (32, 34) and with two coolant outlets (36, 38), characterized in that the valve device (30) is operated in a first valve state, in which the coolant conveyed by means of the pumping device (20) is at one of the coolant inlets (32,34) enters the valve device (30) and exits the valve device (30) at one of the coolant outlets (36, 38), wherein in the first valve state the, Valve device (30) the coolant is conveyed through the cooling device (18) by means of the pump device (20), bypassing both the electrical heating device (22) and the chiller (24).

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