Coolant circuit with flexibly usable electric heating device, motor vehicle and method for operating a coolant circuit

Abstract

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 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 flows and a chiller (24) through which the coolant flows 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), wherein the coolant circuit (10) has a valve device (30) with two coolant inlets (32, 34) and with two coolant outlets (36, 38), wherein the cooling device (18) is arranged in a line branch (42) of the coolant circuit (10), which branches off from another line (44) of the coolant circuit (10) at a branch point (46), wherein the line branch (42) leads from the branch point (46) to one of the two coolant inlets (32, 34), characterized by the fact that the further line (44) leads from the electric heating device (22) to the other of the two coolant inlets (32, 34), wherein the valve device (30) is operable 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), and wherein in the first valve state of the valve device (30) the coolant can be conveyed by means of the pump device (20) by bypassing the chiller (24) through the deactivatable electric heating device (22) and through the cooling device (18).

Description

[0001] 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.

[0002] 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.

[0003] 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.

[0004] 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.

[0005] EP 3 504 408 B1 describes a cooling system for an electric drive unit in a vehicle. A low-temperature circuit for a coolant circulating therein comprises a low-temperature cooler and a bypass line having a heating device. A four-way valve makes it possible to direct the coolant flow through the low-temperature cooler or the bypass line. The four-way valve directs the coolant flow to a chiller. The coolant then enters an electrical energy storage device. The coolant leaving the electrical energy storage device enters a coolant pump, which circulates the coolant in the low-temperature circuit.

[0006] 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 through the battery and through the electric auxiliary heater, or through the battery, through the electric auxiliary heater, and through the chiller.

[0007] The thermal management system described in DE 10 2021 207 249 A1 is not very flexible with regard to the use of the heat provided by the electric auxiliary heating device.

[0008] The object of the present invention is to provide a coolant circuit of the type mentioned at the outset which is particularly flexible with regard to the usability of the heat that can be provided by means of the electric heating device, 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 8, and a method having the features of patent claim 9. 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 cooling device is arranged in a line branch of the coolant circuit, which branches off from another line of the coolant circuit at a branching point.Here, the line branch leads from the branching point to one of the two coolant inlets of the valve assembly. The further line leads from the electric heater to the other of the two coolant inlets.

[0011] Depending on the valve state of the valve device, this ensures that, during operation of the pump device, the coolant is conveyed via the branch line from the branching point to one of the two coolant inlets and / or the coolant is conveyed via the further line from the electric heating device to the other of the two coolant inlets. Consequently, the heat that can be provided by the electric heating device or introduced into the coolant can be used very flexibly in the coolant circuit.

[0012] The valve device is coupled, on the one hand, to the line branch in which the cooling device is located, and, on the other hand, to the further line that originates from the electric heating device and has the branching point. This allows a variety of temperature control functions, such as cooling and / or heating functions, to be easily implemented by placing the valve device in a respective valve state. This contributes to the coolant circuit being very flexible with regard to the utilization of the heat provided by the electric heating device.

[0013] If, for example, ordinal numbers such as "first," "second," "third," and so on are used below to refer to a valve state, these ordinal numbers do not represent a ranking or sequence. Rather, the 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 components of the coolant circuit.

[0014] The valve device is operable in a first valve state, in which the coolant 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 first valve state of the valve device, the coolant can be conveyed by means of the pump device, bypassing the chiller, through the deactivatable or deactivated electrical heating device and through the cooling device. If the valve device is operated according to the first valve state and the electrical heating device is deactivated at the same time, temperature differences within the battery can be compensated for very easily. In this case, the pump device does not need to convey the coolant through the chiller.As a result, the operation of the coolant circuit in the first valve state of the valve device is accompanied by a lower pressure loss than would be the case if the cooling water flowed through the chiller. Accordingly, the coolant circuit allows for an improved temperature control function of the battery.

[0015] Temperature differences within the battery can occur, for example, due to different operating states of the battery's individual battery cells. Furthermore, the battery's battery cells can be arranged in individual battery modules, and the battery can comprise a plurality of such battery modules. If the pumping device causes the coolant to flow through the cooling device, temperature differences between such battery modules can also be effectively compensated.

[0016] Preferably, the valve device is operable in a second 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 one of the coolant outlets. In the second valve state of the valve device, the coolant can be conveyed by means of the pump device, starting from the deactivatable or deactivated electric heating device, through the cooling device and through the chiller.

[0017] If the chiller is operated as an evaporator of the refrigerant circuit in this second valve state of the valve device, cooling of the battery can be advantageously achieved. This is because the refrigerant evaporating in the refrigerant circuit can absorb heat in the chiller and thus extract heat from the coolant. In this way, particularly intensive cooling of the battery can be achieved using the cooling device.

[0018] In this second valve state of the valve device, the coolant flows through the line branch of the coolant circuit. Accordingly, the coolant pumped by the pump device can be pumped from the deactivatable or deactivated electric heater, first through the cooling device, and then through the chiller. This allows for very direct heat dissipation from the battery by operating the chiller as the evaporator of the refrigerant circuit.

[0019] Preferably, the valve device is operable in a third 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 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 activatable or activated electric heating device. Accordingly, activating the electric heating device can heat the battery. This is advantageous, for example, when the battery is to be quickly brought to a favorable operating temperature.When the battery is at the desired operating temperature, it has a high capacity to provide electrical energy, for example, for an electric drive system in a motor vehicle. This is advantageous.

[0020] In particular, the line branch of the coolant circuit branching off from the branching point can be used in the third valve state of the valve device to convey the warm coolant coming from the activated electric heating device through the cooling device. Accordingly, the heat provided by the electric heating device is directly available for heating the battery. Since the cooling device acts as a heating device in this case, the cooling device can also be generally referred to as a temperature control device.

[0021] Preferably, the valve device is operable in a fourth valve state, in which the coolant conveyed or conveyable by the pump device enters the valve device at both 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 and then through the electric heating device.

[0022] Thus, all coolant leaving the valve assembly at exactly one of the coolant outlets is available to transfer heat into the chiller. By transferring heat from the electric heater to the chiller, the vehicle's refrigerant circuit can be put into operation as a heat pump very early on.

[0023] When operating the refrigerant circuit as a heat pump, it is important to ensure that the chiller has a certain minimum temperature. If the chiller has the minimum temperature, stable operation of the refrigerant circuit can be ensured. If the minimum temperature at the chiller is reached quickly, this allows the refrigerant circuit to be activated or commissioned as a heat pump accordingly quickly. For example, at ambient temperatures of around -20°C, the refrigerant circuit can be operated as a heat pump if the coolant heated by the electric heater is fed to the chiller. This allows the passenger compartment of a vehicle to be heated very quickly using the refrigerant circuit operating as a heat pump, even at such low ambient temperatures. This leads to increased comfort for the occupants of the vehicle's passenger compartment.

[0024] At the same time, in the fourth valve state of the valve device, at least a portion of the coolant can be supplied by means of the pump device via the line branch of the cooling device, which is then used to heat the battery. Accordingly, the heat provided by the electric heating device can be used both to heat the battery and to heat the chiller.

[0025] In particular, if a valve device's closure mechanism is adjusted to ensure that different partial coolant flows enter the valve device at the two coolant inlets, the heat provided by the electric heater can be distributed very precisely between the battery and the chiller, as needed. This is advantageous.

[0026] 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 via the line branch having the cooling device 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, on the one hand, via the chiller and, on the other hand, bypassing the chiller, back to the electric heating device.

[0027] This allows for very precise adjustment of the volume flow of coolant supplied to the chiller. In the fifth valve state, a portion of the coolant can be pumped back to the electric heating device, bypassing the chiller. This ensures that only a reduced volume flow, rather than the full volume flow delivered by the pumping device, flows through the chiller. This is advantageous for stable operation of the chiller as an evaporator in the motor vehicle's refrigerant circuit.

[0028] 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.

[0029] The valve device is preferably operable in a sixth valve state, in which the coolant conveyed or conveyable by means of the pump device enters the valve device via the further line and exits the valve device at one of the coolant outlets. In the sixth valve state of the valve device, the coolant can be supplied to the chiller by means of the pump device, bypassing the cooling device. Furthermore, in the sixth valve state of the valve device, the coolant can be conveyed from the chiller by means of the pump device, bypassing the cooling device, back to the electric heating device. This makes it possible to use all of the heat that can be provided or is provided by the electric heating device to increase the temperature of the coolant flowing through the chiller.As a result, the chiller can be brought to its minimum temperature particularly quickly, which allows the refrigerant circuit to operate as a heat pump.

[0030] In the coolant circuit, by moving the valve device to the respective valve state, the heating output of the electric heating device can be distributed completely freely between the heat sinks in the form of the cooling device for the battery and in the form of the chiller. This completely free distribution includes, on the one hand, the function that the battery is heated exclusively by means of the cooling device, which then has a heating function, and, on the other hand, the function that the heat generated by the electric heating device is supplied exclusively to the chiller. Operating the coolant circuit in the corresponding valve states of the valve device is therefore advantageous.

[0031] The valve device preferably has a closure means that can be moved into a plurality of positions. In the respective positions of the closure means, different partial flows of the coolant can be supplied to the valve device via the two coolant inlets by operating the pump device, or can be discharged from the valve device via the two coolant outlets. This makes it possible, in particular, to very precisely meter the partial flows of the coolant to be supplied to the cooling device and the chiller. Consequently, the respective temperature control requirements of the battery and the chiller can be met very effectively.

[0032] When operating the valve device 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 forcibly 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.

[0033] 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.

[0034] Preferably, the electric heating device, the cooling device, the valve device, and the pumping device are arranged in a first sub-circuit of the coolant circuit. The chiller and a further pumping device of the coolant circuit are arranged in a second sub-circuit of the coolant circuit. The coolant can be conveyed through the second sub-circuit by operating the further pumping device, regardless of whether the coolant flows through the first sub-circuit.

[0035] Such a coolant circuit design is advantageous, for example, when components of the motor vehicle arranged in the second subcircuit, such as at least one electric drive device and / or at least one power electronics unit and / or at least one electrical converter or power inverter and / or at least one control unit or the like, dissipate heat. This is because, during heat pump operation of the motor vehicle's refrigerant circuit, this heat can be transferred to the refrigerant evaporating in the chiller. This enables efficient operation of the refrigerant circuit as a heat pump without the need for the electric heating device to contribute heat for this heat pump operation. This is advantageous.

[0036] Furthermore, by operating the pumping device arranged in the first partial circuit, the 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 generally be referred to as a temperature control device.

[0037] Preferably, a further valve device with two coolant inlets and two coolant outlets is arranged in the second partial circuit. By providing such a further four-way valve in the second partial circuit, a respective coolant flow through components of the coolant circuit arranged in the second partial circuit can be adjusted very easily and as needed. This is advantageous.

[0038] The motor vehicle according to the invention has a coolant circuit according to the invention and a battery. The battery is designed to supply electrical energy to at least one electric drive device of the motor vehicle. In the motor vehicle, the coolant circuit can advantageously be used to cool and heat the battery.

[0039] 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 up to several hundred volts. If the electric heating device of the coolant circuit is supplied with electrical energy by the high-voltage battery, the electric heating device designed as an auxiliary heating device can be referred to as a high-voltage heater.

[0040] 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.

[0041] 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.

[0042] 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. By means of the pumping device, coolant can be conveyed through the cooling device. An electric heating device through which the coolant flows 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. The cooling device is arranged in a line branch of the coolant circuit, which branches off from another line of the coolant circuit at a branching point.By operating the pumping device, the coolant is pumped via the branch line from the branching point to one of the two coolant inlets. Additionally or alternatively, by operating the pumping device, the coolant is pumped via the further line from the electric heater to the other of the two coolant inlets.

[0043] The coolant circuit operated in this way is particularly flexible with regard to the utilization of the heat provided by the electric heater. Depending on the valve state of the valve device, the coolant can be introduced into the valve device via the line branch and / or the further line. From there, depending on the valve state of the valve device, the coolant can be pumped further through the coolant circuit via one of the coolant outlets or both coolant outlets.

[0044] In the method according to the invention, the valve device is operated in a first valve state in which the coolant 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, wherein in the first valve state of the valve device the coolant is conveyed by means of the pump device, bypassing the chiller, through the deactivatable electrical heating device and through the cooling device.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049] Exemplary embodiments of the invention are described below. Shown are: Fig. 1 schematically and in detail a coolant circuit for a motor vehicle, which has a valve device operable in several valve states; Fig. 2 the coolant circuit according to Fig. 1 with the valve device in a first valve state, in which a cooling device provided for cooling a battery of the motor vehicle is flowed through by coolant, wherein a chiller is bypassed by the coolant, and wherein an electrical heating device arranged in the coolant circuit is deactivated or taken out of operation; Fig. 3 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; Fig. 4 the coolant circuit according to Fig. 1, wherein the valve device is operated in a third valve state in which the battery is heated; Fig. 5 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 electric heating device; Fig. 6 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 supplied to the chiller on the one hand and is returned to the electric heating device bypassing the chiller on the other hand; Fig. 7 the coolant circuit according to Fig. 1, wherein the valve device is operated in a sixth valve state in which the chiller is supplied with the coolant coming from the electric heating device, bypassing the cooling device; Fig. 8 a variant of the coolant circuit according to Fig. 1, in which a further valve device with two coolant inlets and two coolant outlets is arranged in a second partial circuit of the coolant circuit; and Fig. 9 shows a highly schematic representation of the motor vehicle with the battery and an electric drive system for moving the motor vehicle.

[0050] The exemplary embodiments explained below are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention that can be considered independently of one another, each of which also develops the invention independently of one another. Therefore, the disclosure is intended to encompass combinations of the features of the embodiments other than those shown. Furthermore, the described embodiments can also be supplemented by further features of the invention already described.

[0051] In the figures, the same reference symbols designate elements with the same function.

[0052] In Fig. 1 is a schematic view of a coolant circuit 10 of a Fig. 1 not shown in detail motor vehicle 12 (compare Fig. 9). 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 (cf. Fig. 9) is designed to move the motor vehicle 12 or at least to assist the movement of the motor vehicle 12. Accordingly, the motor vehicle 12 can be designed as an electric vehicle or as a hybrid vehicle.

[0053] 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.

[0054] 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 mode, the cooling device 18 serves to cool the battery 14, and in the heating mode, 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 below.

[0055] 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.

[0056] A chiller 24 is also arranged in the coolant circuit 10. The chiller 24 is a heat exchanger through which the coolant and a refrigerant flow. Accordingly, the chiller 24 is integrated into both the coolant circuit 10 and a refrigerant circuit 26, which is Fig. 1 is shown only schematically and in detail.

[0057] 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 fed into a passenger compartment 28 (see Fig. 9) of the motor vehicle 12 in order to heat the passenger compartment 28.

[0058] 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.

[0059] In the coolant circuit 10, a valve device 30 is arranged, 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.

[0060] In 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. Furthermore, the closure means 40 preferably makes it possible to open only one of the coolant inlets 32, 34 and both coolant outlets 36, 38 at the same time.

[0061] Preferably, a volume flow of the coolant to be distributed between the respective coolant outlets 36, 38 and / or a volume flow of the coolant entering the valve device 30 via the coolant inlets 32, 34 can be adjusted as required, for example by adjusting the closure means 40.

[0062] Different valve states of the valve device 30 are explained below, in particular with reference to possible or advantageous connection options, which are described in Fig. 2 to Fig. 7. In preferred operating states of the coolant circuit 10, 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.

[0063] According to Fig. 1, the cooling device 18 is arranged in a line branch 42 of the coolant circuit 10, which branches off from another line 44 of the coolant circuit at a branching point 46. The line branch 42, in which the cooling device 18 is arranged, leads from the branching point 46 to one of the two coolant inlets 32, 34, for example, to the first coolant inlet 32. The further line 44 leads from the electric heating device 22 to the other of the two coolant inlets 32, 34 of the valve device 30.

[0064] According to Fig. 1, the further line 44 leads to the second coolant inlet 34 of the valve device 30. Depending on the position into which the closure means 40 of the valve device 30 is moved, it can be ensured by operating the pump device 20 that the coolant enters the valve device 30 via the line branch 42 and thus the first coolant inlet 32 ​​and / or via the further line 44 and thus the second coolant inlet 34.

[0065] As a result, the heating power provided by the electric heating device 22 in the activated state of the heating device 22 can be completely freely directed to the heat sinks in the form of the cooling device 18 for cooling the battery 14 (see Fig. 9) and divide it in the form of the chiller 24. Volume flows of the liquid coolant flowing through the cooling device 18 and / or through the chiller 24 can be adjusted by means of the four-way valve designed as a mixing valve in the form of the valve device 30.

[0066] This free distribution of the heating power includes the function that only the cooling device 18 is supplied with coolant, which is heated by means of the electric heating device 22. A corresponding operating state of the coolant circuit 10 with the associated valve state of the valve device 30 is shown in Fig. 4 shown.

[0067] And a function in which the coolant heated by the electric heating device 22 is supplied to the chiller 24 bypassing the cooling device 18 and thus the heat provided by the electric heating device 22 is used exclusively for heating the chiller 24 is in Fig. 7, together with a corresponding valve state of the valve device 30.

[0068] In Fig. 2, the valve device 30 is shown 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. Here, the coolant flows from the branching point 46 exclusively via the line branch 42 to the valve device 30, with the cooling device 18 being arranged in the line branch 42.

[0069] According to Fig. 2, the coolant exits the valve device 30 at one of the coolant outlets 36, 38, in this case at the first coolant outlet 36. In the Fig. In the first valve state of the valve device 30 shown in Figure 2, the coolant is pumped through the deactivated electric heating device 22 by means of the pump device 20, bypassing the chiller 24. The coolant flows through the cooling device 18, thus balancing temperature differences within the battery 14.

[0070] The same function of a pure flow through the cooling device 18, without the electric heating device 22 introducing heat into the coolant, is possible by operating the pumping device 20 and bringing the valve device 30 into a corresponding valve state, in which the coolant exits the valve device 30 at the second coolant outlet 38 and not as in Fig. 2 at the first coolant outlet 36. The coolant then returns to the pumping device 20 via the chiller 24 and a return line 48. A corresponding flow path of the coolant is shown in Fig. 3 illustrates.

[0071] The return line 48 branches off from a line branch 54 of the coolant circuit 10 at a further branching point 52 downstream of the chiller 24 and upstream of a further pumping device 50 or second pumping device 50 of the coolant circuit 10. The chiller 24 is integrated into this line branch 54. Preferably, a check valve 56 arranged in the return line 48 ensures that the coolant can flow through the return line 48 in only one direction.

[0072] If the chiller 24 is not operated as an evaporator of the refrigerant circuit 26, no cooling of the coolant by evaporation of the refrigerant takes place at the chiller 24. Thus, even in this valve state of the valve device 30, a pure flow of the coolant through the cooling device 18 can be achieved to compensate for temperature differences within the battery 14.

[0073] In Fig. However, Figure 3 shows an operating state of the coolant circuit 10 in which the battery 14 is cooled. This is done by the valve device 30 in a Fig. 3 shown second valve state. In the second valve state of the valve device 30, the coolant conveyed by means of the pump device 20 exits at one of the coolant inlets 32, 34, according to Fig. 3 at the first coolant inlet 32, into the valve device 30.

[0074] The coolant exits one of the coolant outlets 36, 38, according to Fig. 3 at the second coolant outlet 38, from the valve device 30. The electric heating device 22 is deactivated in this operating state of the coolant circuit 10, so that the electric heating device 22 does not introduce heat into the coolant. However, the chiller 24 is used as an evaporator of the refrigerant circuit 26 (see Fig. 1). Consequently, heat from the coolant is transferred to the evaporating refrigerant at the chiller 24, thus cooling the coolant. This allows cooling of the battery 14 (see Fig. 9). In the Fig. In the second valve state of the valve device 30 shown in Fig. 3, the cooling device 18 assigned to the battery 14 is thus fluidically connected to the chiller 24.

[0075] According to Fig. 4, the valve device 30 can be operated in a third valve state in which the chiller 24 is bypassed. In this third valve state, the coolant enters one of the coolant inlets 32, 34, according to Fig. 4 at the first coolant inlet 32, into the valve device 30 and at one of the coolant outlets 36, 38, according to Fig. 4 at the first coolant outlet 36, again from the valve device 30.

[0076] Accordingly, the coolant coming from the activated electric heating device 22 and thus heated is supplied exclusively via the line branch 42 and thus the cooling device 18 of the valve device 30. By means of the cooling device 18, heat is transferred to the battery 14 (see Fig. 9), so that a heating function is realized by the cooling device 18. Accordingly, the cooling device 18 can provide a heating function or a cooling function depending on the operating mode of the heat exchangers integrated into the coolant circuit 10.

[0077] According to Fig. 5, the valve device 30 is operable in a fourth valve state, in which the coolant enters the valve device 30 at both coolant inlets 32, 34 and exits the valve device 30 at one of the coolant outlets 36, 38, in this case at the second coolant outlet 38. In the 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 through the electric heating device 22.

[0078] In this respect, the further flow path of the coolant from the chiller 24 back to the pumping device 20 corresponds to the flow path which in Fig. 3. However, in the Fig. 5 shown position of the closure means 40 (compare Fig. 1) of the valve device 30, the coolant is supplied both via the further line 44 and via the line branch 42 to the valve device 30. The volume flow of coolant, which is supplied from the heating device 22 via the line branch 42 of the cooling device 18, causes the battery 14 to be heated (see Fig. 9). And the entire coolant flow conveyed from the second coolant outlet 38 to the chiller 24 serves to introduce heat into the refrigerant flowing through the chiller 24.

[0079] Depending on how much coolant flows through the line branch 42 in the fourth valve state and how much coolant is conveyed through the further line 44 to the chiller 24, the amount of heat applied to the chiller 24 can be precisely metered. This is advantageous for ensuring stable operation of the refrigerant circuit 26 (see Fig. 1) to ensure.

[0080] In Fig. 6 shows a fifth valve state of the valve device 30, in which the coolant conveyed by the pump device 20 is supplied to the valve device 30 via the line branch 42 having the cooling device 18. Thus, the entire coolant enters the valve device 30 at the first coolant inlet 32. However, the closure means 40 (cf. Fig. 1) of the valve device 30 is moved into a position in which the coolant exits the valve device 30 at both coolant outlets 36, 38.

[0081] In this fifth valve state of the valve device 30, the coolant is pumped by means of the pump device 20, starting from the valve device 30, on the one hand, via the chiller 24 and, on the other hand, through the environment of the chiller 24 back to the electric heating device 22. This allows the volume flow of the coolant pumped via the chiller 24 to be adjusted very precisely. If, on the other hand, the entire volume flow of coolant pumped by the pump device 20 were to be pumped through the chiller 24, this could lead to an undesirably high coolant temperature level at the chiller 24.

[0082] By dividing the volume flow at the valve device 30 or by operating the valve device 30 in the fifth valve state, it can be achieved that not the full volume flow conveyed by the pump device 20 flows through the chiller 24, but only a reduced volume flow of the coolant. For proper and stable operation of the refrigerant circuit 26 (see Fig. 1) to set a specific average temperature. For a given coolant temperature, this can be achieved by reducing the volume flow of coolant conveyed through the chiller 24. Therefore, it is advantageous that the valve device 30 can be operated in the fifth valve state.

[0083] According to Fig. 7, the valve device 30 can be operated in a sixth valve state, in which the coolant conveyed by means of the pump device 20 enters the valve device 30 exclusively via the further line 44, according to Fig. 7 via the second coolant inlet 34 of the valve device 30. In this case, the entire coolant exits the valve device 30 at one of the coolant outlets 36, 38, in this case at the second coolant outlet 38, and thus reaches the chiller 24.

[0084] The coolant pumped by the pumping device 20 is thus fed to the chiller 24, bypassing the cooling device 18. Furthermore, the coolant is pumped from the chiller 24 back to the electric heating device 22, bypassing the cooling device 18. This allows a particularly large amount of heat to be introduced into the chiller 24. This enables very early commissioning of the refrigerant circuit 26 as a heat pump, in particular even at very low ambient temperatures, for example at ambient temperatures of approximately -20°C. This leads to an improvement in the heating dynamics of the passenger compartment 28 of the motor vehicle 12 (see Fig. 9) and thus to an increase in comfort for passengers in the passenger compartment 28.

[0085] According to Fig. 2, a first partial circuit 58 of the coolant circuit 10 can be operated decoupled from a second partial circuit 60 of the coolant circuit 10. In this case, the electric heating device 22, the cooling device 18, the valve device 30, and the pump device 20 are arranged in the first partial circuit 58. The chiller 24 and the further pump device 50 or second pump device 50 of the coolant circuit 10, in contrast, are arranged in the second partial circuit 60. If only the second pump device 50 is put into operation, the coolant is pumped through the second partial circuit 60, regardless of whether the first partial circuit 58 is flowing through, i.e., without the first partial circuit 58 of the coolant circuit 10 needing to be flowed through by coolant for this purpose.

[0086] At least one further component 62 is arranged in the second partial circuit 60, the cooling and / or heating of which may be desirable. The respective components 62 can be supplied with coolant by means of at least one heat exchanger integrated into the second partial circuit 60. The at least one heat exchanger can be configured to dissipate heat from the coolant and / or to absorb heat from the coolant.

[0087] For example, the components 62 may include at least one heat exchanger for cooling the electric drive device 16 (see Fig. 9) 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.

[0088] In Fig. Figure 8 schematically shows a possible configuration of the second partial circuit 60. Thus, the at least one component 62 to be cooled and / or heated can be arranged in the second partial circuit 60, as can an air-cooled heat exchanger 64. Heat can thus be dissipated via this heat exchanger 64 by supplying air to the heat exchanger 64 while the coolant conveyed by the second pump device 50 flows through the heat exchanger 64.

[0089] In particular, at least one further valve device 66 can be arranged in the second partial circuit 60 of the coolant circuit 10, by means of which coolant flows through the at least one component 62 and / or the coolant-air heat exchanger 64 can be adjusted as required during operation of the second pump device 50.

[0090] According to Fig. 8, this additional valve device 66 can be designed analogously to the valve device 30 arranged in the first partial circuit 58 and thus as a four-way mixing valve. The valve device 66 can accordingly also have two coolant inlets 68, 70 and two coolant outlets 72, 74.

[0091] Depending on the position of a closure means (not shown) of the further valve device 66, the coolant coming from the components 62 can be returned to the pump device 50 using the heat exchanger 64 or bypassing the heat exchanger 64. The coolant can be conveyed through a return line 76 connected to the first coolant outlet 72, which is connected to one of the coolant outlets 72, 74, in this case to the first coolant outlet 72. The return line 76 opens into the line branch 54 of the second partial circuit 60 upstream of the second pump device 50.

[0092] Furthermore, the coolant coming from the at least one component 62 can leave the further valve device 66 at the second coolant outlet 74 and then be returned to the second pump device 50 via the chiller 24. A further check valve 80 can be arranged in the line branch 54 of the second partial circuit 60 that opens into the chiller 24. The further check valve 80 ensures that the line branch 54 can only flow in one direction, namely toward the chiller 24.

[0093] The provision of the further valve device 66 in the form of the four-way mixing valve allows a very flexible operation of the second partial circuit 60 of the coolant circuit 10. In Fig. 1 to 7, the heat exchanger 64 and the further valve device 66 of the second partial circuit 60 are not shown in detail for reasons of clarity.

[0094] 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

[1] 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), wherein the coolant circuit (10) has a valve device (30) with two coolant inlets (32, 34) and with two coolant outlets (36, 38), wherein the cooling device (18) is arranged in a line branch (42) of the coolant circuit (10), which branches off from a further line (44) of the coolant circuit (10) at a branching point (46), wherein the line branch (42) leads from the branching point (46) to one of the two coolant inlets (32, 34), characterized by , that the further line (44) leads from the electrical heating device (22) to the other of the two coolant inlets (32, 34), wherein the valve device (30) is operable 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), and wherein in the first 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 deactivatable electrical heating device (22) and through the cooling device (18). [2] Coolant circuit (10) according to claim 1, characterized byin 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) starting from the deactivatable electrical heating device (22) through the cooling device (18) and through the chiller (24), in particular starting from the deactivatable electrical heating device (22) first through the cooling device (18) and then through the chiller (24). [3] Coolant circuit (10) according to one of the preceding claims, characterized byin 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 activatable electrical heating device (22), in particular starting from the valve device (30) first through the activatable electrical heating device (22) and then through the cooling device (18). [4] Coolant circuit (10) according to one of the preceding claims, characterized bythat 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 both 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) and then through the electrical heating device (22). [5] Coolant circuit (10) according to one of the preceding claims, characterized byin that the valve device (30) is operable in a fifth 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) via the line branch (42) having the cooling device (18) 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) on the one hand via the chiller (24) and on the other hand bypassing the chiller (24) back to the electric heating device (22). [6] Coolant circuit (10) according to one of the preceding claims, characterized bythat the valve device (30) is operable in a sixth valve state, in which the coolant conveyed by means of the pump device (20) enters the valve device (30) via the further line (44) and exits the valve device (30) at one of the coolant outlets (36, 38), wherein in the sixth valve state of the valve device (30) the coolant can be fed to the chiller (24) by means of the pump device (20), bypassing the cooling device (18), and can be conveyed from the chiller (24) back to the electrical heating device (22), bypassing the cooling device (18). [7] Coolant circuit (10) according to one of the preceding claims, characterized byin that the electric heating device (22), the cooling device (18), the valve device (30) and the pump device (20) are arranged in a first partial circuit (58) of the coolant circuit (10), wherein the chiller (24) and a further pump device (50) of the coolant circuit (10) are arranged in a second partial circuit (60) of the coolant circuit (10), wherein the coolant can be conveyed through the second partial circuit (60) by operating the further pump device (50) independently of flow through the first partial circuit (58), and wherein a further valve device (66) with two coolant inlets (68, 70) and with two coolant outlets (72, 74) is arranged in the second partial circuit (60). [8] 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). [9] 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 can be conveyed through the cooling device (18), wherein an electric heating device (22) through which the coolant flows and a chiller (24) through which the coolant flows 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), wherein the cooling device (18) is arranged in a line branch (42) of the coolant circuit (10), which is connected to a further line (44) of the coolant circuit (10) branches off at a branching point (46),wherein by operating the pumping device (20) the coolant is conveyed via the line branch (42) from the branching point (46) to one of the two coolant inlets (32, 34), , characterized by that the coolant is additionally or alternatively conveyed via the further line (44) from the electrical heating device (22) to the other of the two coolant inlets (32, 34), wherein the valve device (30) is 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), and wherein in the first valve state of the valve device (30), the coolant is conveyed by means of the pump device (20), bypassing the chiller (24), through the deactivatable electrical heating device (22) and through the cooling device (18).

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