Heat pump arrangement with indirect battery heating for a battery electric motor vehicle and method of operating a heat pump arrangement

Abstract

The invention relates to a heat pump arrangement and a method of operating a heat pump arrangement. The heat pump arrangement has a refrigerant circuit and a coolant circuit, wherein the coolant circuit is configured for indirect battery heating.

Description

TECHNICAL FIELD

[0001] The present invention relates to a heat pump arrangement with indirect battery heating for a battery electric motor vehicle.

[0002] The present invention also relates to a method of operating a heat pump arrangement in selected operating modes.

[0003] The field of application of the present invention is the field of electric vehicles that typically use high voltage batteries (HV batteries) as energy storage devices for supplying energy to the drivetrain of the vehicle. BACKGROUND

[0004] The efficient thermal supply of the vehicle plays an important role in combination with the optimal thermal management of the battery and the electric drivetrain.

[0005] Battery electric vehicles generate relatively little waste heat and therefore it is often necessary in such vehicles to efficiently generate heat for heating the passenger compartment and make it available in sufficient quantities at the appropriate temperature level.

[0006] In the prior art, for this series of ideas, refrigerant circuits and heat pump circuits for refrigeration systems are known that are specifically tailored for battery electric vehicles.

[0007] However, these systems are often complex and rarely able to combine the need and the requirement of the vehicle occupants for an adequate thermal supply via the air conditioning system of the vehicle with the optimal required cooling or heating of the battery and the electric drivetrain in various operating states. SUMMARY

[0008] TECHNICAL PROBLEM

[0009] The object of the present invention is to provide a heat pump arrangement for a battery electric vehicle that combines the increased efficiency of a heat pump for supplying heat to an air conditioning system for the passenger compartment of a motor vehicle with the possibility of optimal thermal supply for the battery, which in addition to efficient cooling also includes the required heating in certain operating states.

[0010] SOLUTION TO THE PROBLEM

[0011] This object is achieved by a heat pump arrangement and a method with the features recited in the embodiments. Further developments are set forth in the preferred embodiments.

[0012] The object of the present invention is achieved by a heat pump arrangement with indirect battery heating for a battery electric motor vehicle, which is achieved by means of a circuit arrangement characterized as follows.

[0013] The heat pump arrangement has a refrigerant circuit with a compressor, a heating condenser, a first three-way expansion valve, an external heat exchanger, at least one evaporator with an associated first expansion element, and a second three-way expansion valve arranged in parallel to the evaporator, and a battery chiller. In this case, a first bypass with a second expansion element and a drive train chiller is branched off between the heating condenser and the first three-way expansion valve.

[0014] Furthermore, the heat pump arrangement has a coolant circuit with a coolant cooler and a battery heat exchanger with an associated first coolant pump, and at least one drive train cooler arranged in parallel to the battery heat exchanger with an associated second coolant pump. In this case, on the coolant side, a battery temperature control loop with the battery heat exchanger, the first coolant pump, the first three-way valve and the battery chiller is formed with an electric drive cooling loop with the drive train cooler, the second coolant pump, the second three-way valve and the drive train chiller in such a way that the battery temperature control loop and the electric drive cooling loop can be operated independently of each other and independently of the coolant circuit as separate circuits. Furthermore, the heat pump arrangement has a heating circuit formed by the heating condenser, a third coolant pump, a heating device and a thermal heat exchanger, and the heating circuit has an indirect battery heating loop. The indirect battery heating loop can be connected to the heating circuit via a third three-way valve and has an indirect heat exchanger which transfers heat from the battery heating loop into the refrigerant circuit or into a thermal carrier circuit, which is referred to as a secondary bypass circuit and is formed as part of the coolant circuit by the battery heat exchanger, the first coolant pump, the first three-way valve and the indirect heat exchanger. The indirect heat exchanger couples the battery heating loop of the heating circuit with the secondary bypass circuit, so that heat of the heating condenser can be transferred from the refrigerant circuit via the heating circuit and the indirect battery heating loop in the indirect heat exchanger to the secondary bypass circuit and finally to the battery heat exchanger. Alternatively or additionally, heat from the heating device can be transferred via the heating circuit and the indirect battery heating loop in the indirect heat exchanger to the secondary bypass circuit and finally to the battery heat exchanger.

[0015] It is particularly advantageous if the first three-way expansion valve and the second three-way expansion valve are formed with an expansion function and a bypass function.

[0016] Furthermore, it is advantageous if a heating condenser bypass is arranged in the refrigerant circuit as a connection between the high-pressure outlet of the compressor and the first three-way expansion valve. The refrigerant can be guided from the compressor to the external heat exchanger via the heating condenser bypass, bypassing the heating condenser.

[0017] The refrigerant collector is preferably arranged in the refrigerant circuit upstream of the compressor, wherein the location information relates to the flow direction of the fluid.

[0018] The battery electronics cooler is advantageously arranged in the secondary bypass circuit in order to optimally control the temperature of the control and regulating components in the battery in addition to the battery itself and thereby to cool or, if necessary, to heat these control and regulating components.

[0019] The external heat exchanger and the coolant cooler are preferably combined in a cooler unit, wherein the external heat exchanger is arranged downstream of the coolant cooler in the flow direction of the ambient air.

[0020] Furthermore, a second bypass is advantageously arranged in parallel to the battery chiller in the refrigerant circuit.

[0021] The object of the application is also achieved by a method of operating a heat pump arrangement for active cooling of a vehicle cabin, in which method the refrigerant downstream of the compressor flows via a heating condenser bypass and a first three-way expansion valve to an external heat exchanger operating as a condenser, and is subsequently expanded in a first expansion element and evaporated in an evaporator. The battery heat exchanger flows the coolant through the battery heat exchanger, and at the same time, the battery temperature control loop and the secondary bypass circuit are operated in parallel. The coolant circuit is further operated by a coolant cooler and a drive train cooler for passive cooling of the drive train.

[0022] Advantageously, a method of operating a heat pump arrangement for active cooling of a vehicle battery is formed, in which method the refrigerant downstream of the compressor flows via a heating condenser bypass and a first three-way expansion valve to an external heat exchanger operating as a condenser, and is subsequently expanded in a second three-way expansion valve and evaporated in a battery chiller. The battery temperature control loop with the battery chiller, the battery heat exchanger is connected in parallel with a battery electronics cooler and in a secondary bypass. The coolant circuit is operated by a coolant cooler and a drive train cooler for passive cooling of the drive train.

[0023] The operation of the refrigerant circuit in the evaporator provides cold. In addition to the evaporator of the air conditioning system, the battery chiller and the drive train chiller also function as evaporators in the refrigerant circuit.

[0024] Advantageously, the refrigerant circuit is operated by a coolant cooler and a battery heat exchanger and a drive train cooler connected in parallel thereto for passive cooling of the vehicle battery, wherein the secondary bypass circuit is operated in parallel by a battery electronics cooler.

[0025] Preferably, the coolant circuit is operated through a coolant cooler and a drive train cooler for passive cooling of the drive train, wherein the battery temperature control loop with the battery heat exchanger and the secondary bypass circuit with the battery electronics cooler are operated parallel to each other and independently of the coolant circuit.

[0026] According to the configuration of the method for the reheat mode of the vehicle cabin, downstream of the compressor, the refrigerant is routed via the heating condenser and the first three-way expansion valve to the external heat exchanger operating as a condenser or evaporator and subsequently expanded in the first expansion element and evaporated in the evaporator. The battery temperature control loop and the secondary bypass are operated in parallel. The electric drive cooling loop with the drive train cooler and the heating circuit with the heating condenser are also operated in this mode.

[0027] The reheat mode of the vehicle air conditioning system is understood to mean an air treatment in which the air is first cooled and dehumidified and then heated to the desired temperature. Both cooling the air and heating the air are therefore required in the air conditioning system.

[0028] In the method for the reheat mode of the vehicle cabin, the heating device is also preferably operated in the heating circuit.

[0029] In the reheat mode of the vehicle cabin, the part flow of the refrigerant downstream of the heating condenser is preferably routed through the first bypass and expanded in the second expansion element and evaporated in the drive train chiller in order to absorb further waste heat of the drive train components.

[0030] Likewise, in order to reheat the vehicle cabin, the intermediate pressure level in the external heat exchanger is preferably set in such a way that the temperature of the refrigerant in the external heat exchanger corresponds to the temperature of the ambient air.

[0031] In order to heat the vehicle cabin with waste heat of the drive train, the refrigerant downstream of the compressor is preferably guided through the heating condenser and the first bypass and subsequently expanded in the second expansion element and evaporated in the drive train chiller. The battery heat exchanger flows the coolant through the battery heat exchanger and the battery temperature control loop and the secondary bypass are operated in parallel. The electric drive cooling loop with the drive train cooler and the heating circuit with the heating condenser and the thermal energy heat exchanger are operated in the same way.

[0032] To heat the vehicle cabin with ambient heat, the refrigerant downstream of the compressor is guided via the heating condenser to the first three-way expansion valve and expanded and evaporated in the external heat exchanger. The battery heat exchanger flows the coolant through the battery heat exchanger and at the same time, the battery temperature control loop and the secondary bypass operate in parallel. The electrically driven cooling loop with the drive train cooler and the heating circuit with the heating condenser and the thermal energy heat exchanger operate in the same way.

[0033] To indirectly heat the battery, the heating circuit is heated to the desired temperature with the heating device and the heat carrier of the heating circuit is routed to the indirect heat exchanger via the third three-way valve and the indirect battery heating loop. In this case, the heating condenser and the thermal energy heat exchanger do not operate. The secondary bypass circuit absorbs the heat in the indirect heat exchanger and releases it to the battery heat exchanger. The electrically driven cooling loop operates alone by the drive train cooler.

[0034] To indirectly heat the battery with waste heat of the drive train, the refrigerant downstream of the compressor flows through the heating condenser and the first bypass. The refrigerant then reaches the second expansion element, expands and is finally evaporated in the drive train chiller. The electrically driven cooling circuit operates accordingly, wherein the waste heat is used for the evaporation of the refrigerant in the drive train chiller. The heating circuit and the indirect battery heating loop operate and deliver the heat of condensation via the indirect heat exchanger to the battery heat exchanger. In this mode, the heating device in the heating circuit does not operate.

[0035] To indirectly heat the battery with ambient heat, the refrigerant downstream of the compressor is guided via the heating condenser to the first three-way expansion valve and at the same time, the refrigerant is expanded and evaporated in the external heat exchanger. The refrigerant then flows via the second three-way expansion valve in the bypass to the battery chiller, wherein the heating device does not operate. The heating circuit and the indirect battery heating loop operate and deliver the heat of condensation from the heating condenser to the battery heat exchanger via the indirect heat exchanger.

[0036] Indirect heating of the battery is understood to mean that the heat or waste heat from various sources and coolant or heat carrier or refrigerant circuits for heating the battery is indirectly transferred to the battery via one or more heat exchangers one or more times.

[0037] In the context of the present invention, a thermal energy heat exchanger is understood to mean a heat exchanger within the air conditioning system of a motor vehicle which releases heat to the air flow of the air conditioning system for heating the passenger compartment. The heating condenser thermally couples the refrigerant circuit and the coolant circuit as a heat exchanger. Within the refrigerant circuit, the heating condenser fulfils the function of a condenser and releases the heat of condensation to the coolant circuit. Depending on its function, the coolant circuit is referred to as a heating circuit. The heat exchanger is provided as an external heat exchanger which, as a radiator, absorbs heat from the ambient air in the heat pump mode of the arrangement or releases heat to the ambient air in the refrigeration system mode.

[0038] The battery chiller is a heat exchanger which is integrated on one side into the refrigerant circuit and on the other side into the coolant circuit, wherein the battery chiller supplies cold on the coolant side to the battery heat exchanger and releases heat on the refrigerant side.

[0039] The refrigerant collector is also referred to as an accumulator and can optionally also be implemented and operated as a separator for liquid refrigerant upstream of the compressor.

[0040] A bypass is understood to mean a refrigerant line which bypasses components of the refrigerant circuit or which leads a partial refrigerant mass flow in parallel to the relevant components.

[0041] The coolant circuit of the vehicle is thermally coupled to the refrigerant circuit via the chiller and usually contains a water-glycol mixture which functions as a coolant or heat carrier depending on the operating state of the overall system.

[0042] The coolant cooler is a radiator which releases heat to the ambient air. The battery heat exchanger absorbs waste heat from the battery in the coolant circuit and dissipates it in order to enable optimum operation of the battery. The drive train cooler also absorbs heat from components of the drive train in order to cool the drive train. Components of the drive train are, for example, components which generate electronic waste heat, and the electric motor drive itself.

[0043] The thermal management system comprises a fully fledged heat pump system with which heat can be obtained from the ambient air and waste heat from the electric drive train components.

[0044] On the refrigerant side, the condensation heat can be released either into the A / C- coolant circuit by means of a water-cooled heating condenser or into the ambient air by means of an external heat exchanger. The use of a three-way refrigerant valve with expansion function between the heating condenser, which is also referred to as water-cooled condenser, and the external heat exchanger enables the utilization of a bypass to bypass the water-cooled condenser on the refrigerant side or to change or expand the pressure level between the water-cooled condenser and the external heat exchanger. By setting this so-called intermediate pressure level, the external heat exchanger can be used as a condenser for releasing heat into the environment or as an evaporator for absorbing heat from the ambient air.

[0045] A battery temperature control loop and an electric drive cooling loop are used to absorb the waste heat of the HV battery and the electric drive components. These two coolant circuits can be merged or completely separated from each other, depending on whether the heat is to be released into the ambient air or is to be recovered.

[0046] The system uses a battery chiller, which can actively cool the battery, and a drive train chiller, which is used to absorb the waste heat from the electrical and electronic drive components and to provide it as evaporation heat to the refrigerant circuit. In a combined heat pump mode, which corresponds to the combined use of ambient air and the waste heat of the electric drive train components as heat sources, the refrigerant mass flow between the external heat exchanger and the drive train chiller is divided into two parallel flows. The passage of the two components in parallel leads to a reduction of the pressure loss on the suction side of the refrigerant circuit. In a pure water heat pump operation, downstream of the water-cooled condenser, the refrigerant is guided to bypass the external heat exchanger and directly to the drive train chiller. In this way, the waste heat from the electrical and electronic drive components can be absorbed at a higher temperature level, which can be significantly above the ambient temperature. This enables the system to operate at a higher suction pressure, which at the same time leads to a higher performance and efficiency.

[0047] By using a three-way coolant valve at the outlet of the heating register, the coolant flow can be diverted by means of an indirect coolant-coolant heat exchanger. This heat exchanger serves to transfer heat from the indirect battery heating loop of the heating circuit into the secondary bypass circuit, wherein, in the operating mode in which heat is transferred into the battery temperature control loop, the battery is heated. In this way, the HV-PTC of the heating device can be used to heat the battery. In this case, however, the condensation residual heat from the refrigerant circuit can also be fed via the heating circuit into the battery temperature control loop in order to be used there as evaporating heat in the battery chiller or as a heat source for heating the battery. The indirect heat exchanger is installed in the bypass line to the battery chiller, i.e. the secondary bypass circuit, so that in active battery cooling, this component is not subjected to the main coolant volume flow circulating between the battery heat exchanger of the HV battery and the battery chiller for cooling the battery. In this way, the indirect heat exchanger does not cause any additional pressure loss in the battery cooling mode.

[0048] It is particularly advantageous that with this particular system up to fifteen different operating modes can be set. In this case, four different operating modes for cooling at ambient temperatures between 25°C and 50°C are implemented as cabin cooling, active battery cooling, passive battery cooling and drive train cooling.

[0049] In the dehumidification and reheating mode at ambient temperatures of 0°C to 25°C, five operating modes for cabin air dehumidification and cabin reheating circuit are implemented.

[0050] As a third main operating mode for heating at temperatures between -18°C and 0°C, six operating modes are implemented which can be subdivided into the groups of cabin heating and battery heating. BRIEF DESCRIPTION OF DRAWINGS

[0051] Further details, features and advantages of the configuration of the present application emerge from the following description of exemplary embodiments with reference to the associated drawings.

[0052] Figure 1 : shows the refrigeration system and heat pump circuit,

[0053] Figure 2 : shows the cabin cooling,

[0054] Figure 3 : shows the active battery cooling,

[0055] Figure 4 : shows the passive battery cooling,

[0056] Figure 5 : shows driveline cooling,

[0057] Figure 6 : shows cabin dehumidification,

[0058] Figure 7 : shows cabin re-heating,

[0059] Figure 8 : shows cabin re-heating using driveline waste heat,

[0060] Figure 9 : shows cabin re-heating using heating device or refrigeration system waste heat,

[0061] Figure 10 : shows cabin heating using heating device,

[0062] Figure 11 : shows cabin heating using driveline waste heat,

[0063] Figure 12 : shows cabin heating,

[0064] Figure 13 : shows battery heating using heating device,

[0065] Figure 14 : shows battery heating using driveline waste heat,

[0066] Figure 15 : shows battery heating using ambient heat, and

[0067] Figure 16 : shows refrigeration system circuit with increased cooling capacity. DETAILED DESCRIPTION

[0068] Figure 1 A refrigeration system and heat pump circuit for a heat pump arrangement with indirect battery heating for a battery powered motor vehicle is shown in a schematic diagram. The system essentially comprises a refrigerant circuit thermally coupled to a coolant circuit via various indirect heat exchangers.

[0069] In the basic form of the refrigerant circuit, the refrigerant circuit comprises a compressor 1 and a heating condenser 2, also referred to as a water-cooled condenser 2. Downstream of the heating condenser 2, a three-way expansion valve 3 and an external heat exchanger 4 are arranged on the refrigerant side. Furthermore, downstream of the external heat exchanger 4, an evaporator 5 and a battery chiller 9 are arranged in parallel in the refrigerant circuit, after which the refrigerant is fed back to the compressor 1 via an accumulator 10. In accordance with the application, the battery chiller 9 is thermally coupled to the coolant circuit via an indirect heat exchanger 6. Figure 1In the illustration, two evaporators 5 are connected in parallel, which are configured as an evaporator 5 for the front region of an air conditioning system of a vehicle and an evaporator 5 for the rear region of an air conditioning system of a vehicle, for example. An associated expansion element 6 is assigned to each of the evaporators 5, wherein a three-way expansion valve 8 is assigned to the battery chiller 9. The three-way expansion valve 8 has an outlet to a bypass 13, which is connected to bypass the battery chiller 9 and to route the refrigerant directly to the refrigerant collector 10.

[0070] The refrigerant circuit also has a heating condenser bypass 36, which bypasses the water-cooled condenser 2 in parallel directly downstream of the compressor 1 and is reintegrated into the refrigerant circuit in the three-way expansion valve 3.

[0071] Furthermore, the refrigerant circuit has a bypass 12, which forms a branch downstream of the heating condenser 2 and guides the refrigerant via an expansion element 14 to an associated drive train chiller 15, after which the refrigerant is fed to the compressor 1 via the refrigerant collector 10, which is also referred to as an accumulator.

[0072] The refrigerant circuit is thermally coupled to an A / C coolant circuit as well as a battery coolant circuit and an e-drive train circuit. The A / C coolant circuit comprises a heating circuit 34, which is routed on the coolant side from the heating condenser 2 via a coolant pump 27 and a heating device 24 to the thermal energy heat exchanger 7. Furthermore, the heating circuit 34 contains an indirect battery heating loop 32, which is routed downstream of the thermal energy heat exchanger 7 via a three-way valve 31 to the indirect heat exchanger 11 and is configured as a loop of the heating circuit. The battery temperature control loop and the e-drive train cooling loop are part of a coolant circuit 17, which initially comprises a coolant cooler 18, in which ambient air 29 absorbs or releases heat.

[0073] The coolant cooler 18 is accommodated together with the external heat exchanger 4 in a cooler unit 30 of the motor vehicle. The coolant circuit 17 branches off in parallel to the cooling of a battery heat exchanger 19 and to the cooling of a drive train cooler 16. The battery temperature control loop 22 contains the battery heat exchanger 19 and has two three-way valves 25 as well as a battery chiller 9. This coolant circuit is driven by a coolant pump 20.

[0074] Furthermore, a two-stage bypass circuit 35 is provided in the battery temperature control loop, which is decoupled via the three-way valves 25 and is guided via the indirect heat exchanger 11 and a battery electronics cooler 33 as well as the battery heat exchanger 19.

[0075] The indirect heat exchanger 11 thermally couples the indirect battery heating loop 32 with the secondary bypass loop 35. Through the indirect heat exchanger 11, heat of the heating loop 34 is transferred from the heating condenser 2 via the indirect battery heating loop 32 to the secondary bypass loop 35, which eventually releases heat to the battery heat exchanger 19.

[0076] On the coolant side, the drive train cooler 16 is integrated into the electrically driven cooling loop 23, which can be actively cooled via the drive train chiller 15. According to Figure 1 , two drive train coolers 16 are provided for the front and rear region, wherein the coolant pump 21 delivers coolant. The electrically driven cooling loop 23 branches off from the coolant circuit 17 downstream of the coolant pump 21 via a three-way valve 26.

[0077] With the refrigeration system and heat pump circuit shown in Figure 1 , various thermal management methods of modern battery electric vehicles can be operated. In the following Figures 2 to 16 , different variants of the method for cooling or heating supply are shown and explained.

[0078] Figure 2 The mode of cabin cooling is shown in Fig. 6. For cabin cooling, the compressor 1 is operated and compresses the refrigerant, which then reaches the external heat exchanger 4 via the heating condenser bypass 36 and the three-way expansion valve 3, condenses there, releases heat and then expands in the expansion element 6 and evaporates in the associated evaporator 5 with the heat absorbed from the cabin air. After passing through the non-return valve 28 to the refrigerant collector 10 and to the compressor 1, the circuit is closed.

[0079] As an example, Figure 2 two evaporators 5 are shown connected in parallel, wherein one evaporator 5 is the front evaporator of a modern multi-zone air conditioning system and the other evaporator 5 is the rear evaporator of a modern multi-zone air conditioning system. After the coolant has absorbed heat in the drive train cooler 16, the coolant circuit 17 is routed via the coolant pump 21 to the coolant cooler 18, which releases heat as a radiator to the ambient air 29. The cooled coolant then reaches the drive train cooler 16; the circuit is closed. Independently of the coolant circuit 17, the battery temperature control loop 22 is implemented by the battery heat exchanger 19 and the coolant pump 20 as well as the parallel connection of the indirect heat exchanger 11 and the battery electronics cooler 33. The coolant flows in parallel through the battery chiller 9, which is not operated on the refrigerant side, and through the branch of the indirect heat exchanger 11 to the battery heat exchanger 19. The battery temperature control loop 22 is coupled in parallel to the secondary bypass loop 35 and can be operated independently of the coolant circuit 17.

[0080] In summary, in this mode, the air flowing into the cabin is cooled by two evaporators 5 arranged in parallel for the front and rear regions of the air conditioning system of the vehicle.

[0081] In this case, the refrigerant is guided around the water-cooled condenser 2. The connections 1 to 3 of the three-way expansion valve 3 between the water-cooled condenser 2 and the external heat exchanger 4 are completely open, so that the refrigerant flows from the compressor 1 into the external heat exchanger 4 without any significant pressure loss. In the external heat exchanger 4, the condensation heat of the refrigerant is released into the ambient air 29. The refrigerant expands into the evaporators 5 arranged in parallel in order to cool the air flowing into the cabin.

[0082] Figure 3 Active battery cooling is shown. In contrast to the passive cooling shown in Fig. 1, no fluid passes through the evaporators 5, but instead, a liquid refrigerant is supplied to the battery chiller 9 with the associated three-way expansion valve 8 for evaporation. The refrigerant vapor is then routed via the refrigerant collector 10 to the compressor 1. The cold provided in the battery chiller 9 is delivered via the battery temperature control loop 22 to the battery heat exchanger 19, and thus the battery heat exchanger is cooled. In parallel, the battery electronics cooler 33 is also supplied with cold. The drive train cooler 16 works in the coolant circuit 17, the coolant pump 21 delivers coolant for indirect cooling via the coolant cooler 18, wherein the ambient air 29 absorbs the heat of the drive train components. Figure 2

[0083] In summary, in this mode, the HV battery is actively cooled by releasing heat to the refrigerant. In this case, the refrigerant is guided around the water-cooled condenser 2 in the heated condenser bypass 36. The connections 1 to 3 of the three-way expansion valve 3 between the water-cooled condenser 2 and the external heat exchanger 4 are completely open, so that the refrigerant flows from the compressor 1 into the external heat exchanger 4 without any significant pressure loss. In the external heat exchanger 4, the condensation heat of the refrigerant is released into the ambient air 29. The refrigerant expands into the battery chiller 9 in order to cool the coolant flowing through the chiller.

[0084] The battery electronics integrated around the HV battery in the secondary bypass circuit 35 are also cooled by the coolant exiting the battery heat exchanger 19. The fluid passing through the secondary bypass circuit 35 is regulated by the first three-way valve 25 downstream of the battery heat exchanger 19, so that a main volume flow flows through the battery chiller 9, while an auxiliary volume flow flows through the battery electronics cooler 33.

[0085] Figure 4 ​Passive battery cooling is shown. In this case, the coolant circuit 17 is operated through the coolant cooler 18 and the coolant is routed in parallel through the battery heat exchanger 19 and the battery electronics cooler 33 as well as through the driveline cooler 16. According to Figure 4 these parallel branches are operated by the coolant pump 20 and the coolant pump 21.

[0086] In this mode, the HV battery is passively cooled by releasing heat to the ambient air 29. In this case, the waste heat of the HV battery is released into the ambient air 29 via the coolant cooler 18 together with the waste heat of the electric driveline, the coolant cooler 18 being classified as a low temperature cooler according to its temperature level.

[0087] The battery electronics integrated around the HV battery in the secondary bypass circuit 35 are cooled by the coolant leaving the battery heat exchanger 19. The flow through the secondary bypass circuit 35 is regulated by the first three-way valve 25 downstream of the battery heat exchanger 19 so that a main volume flow is flowing through the battery heat exchanger 19 and an auxiliary volume flow is flowing through the battery electronics cooler 33.

[0088] Figure 5 Driveline cooling is shown, wherein, in contrast to Figure 4 the battery heat exchanger 19 is operated independently from the coolant circuit 17 via the battery temperature control loop 22 and the secondary bypass circuit 35. Only the driveline cooler 16 is integrated in the coolant circuit 17 and is passively cooled by releasing heat in the coolant cooler 18 through the ambient air 29.

[0089] In summary, in this mode, the electric driveline is cooled by circulating coolant between the electrical and electronic drive components and the coolant cooler 18. In this way, the waste heat is absorbed by the coolant and released into the ambient air 29.

[0090] Figure 6 Vehicle cabin dehumidification is shown. For vehicle cabin dehumidification, the refrigerant circuit is operated to dehumidify the vehicle cabin air. For this purpose, the compressor 1 compresses the refrigerant which is then routed to the external heat exchanger 4 via the heating condenser bypass 36 and the three-way expansion valve 3, where the refrigerant releases heat into the ambient air 29. The condensed refrigerant is finally expanded in the expansion element 6 of the evaporator 5 and then evaporated in the evaporator 5. The humidity in the vehicle cabin air condenses on the evaporator and is thereby removed from the air. The refrigerant gas reaches the compressor 1 again via the refrigerant collector 10. As Figure 5 described, the coolant circuit 17 as well as the battery temperature control loop 22 and the secondary bypass circuit 35 are functioning in this mode.

[0091] Figure 7A reheating mode of the vehicle cabin is shown. In the reheating mode, both heat and cold are provided to the vehicle cabin and the air of the vehicle cabin is first dehumidified and then heated to the desired temperature. To this end, the refrigerant in the compressor 1 is guided over the heating condenser 2, at which the refrigerant releases heat to the heating circuit 34, which guides the coolant, which in this mode acts as a heat carrier, through the thermal energy heat exchanger 7, at which heat is released into the air of the vehicle cabin. Downstream of the heating condenser 2, the refrigerant reaches the external heat exchanger 4 and, after expansion in the expansion element 6, reaches the evaporator 5, in which heat for dehumidifying the air is absorbed. The battery temperature control loop 22 and the secondary bypass circuit 35 are operated against the battery heat exchanger 19, and the electric drive cooling circuit 23 is operated independently thereof by the drive train cooler 16.

[0092] In summary, in this mode, the air flowing into the vehicle cabin is first dehumidified and then heated to the desired temperature. The air is dehumidified when flowing through the evaporator 5. Downstream of the evaporator 5, the air is heated when flowing through the thermal energy heat exchanger 7.

[0093] In this case, the refrigerant flows through the water-cooled condenser 2 on the high-pressure side. The connection 2 to 3 of the three-way expansion valve 3 between the heating condenser 2 and the external heat exchanger 4 is adjusted in order to set the heat required in the case of reheating into the coolant circuit or to release excess condensation heat of the refrigerant into the ambient air 29. This can be achieved, for example, by setting the pressure level in the external heat exchanger 4. Depending on the ambient temperature and the corresponding heating or cooling capacity required, the external heat exchanger 4 can be operated as a condenser for releasing condensation heat into the environment or as an evaporator for absorbing evaporation heat from the ambient air 29.

[0094] In Figure 8 , the reheating operation of the vehicle cabin is operated in an extended mode, according to which the refrigerant system circuit is extended by the following: via the bypass 12, a part of the fluid reaches the drive train cooler 15 with the associated expansion element 14. In this way, the drive train cooler 15 is actively cooled and the coolant of the electric drive cooling circuit 23 cools the drive train cooler 16.

[0095] In addition to the operating modes described above in Figure 7 , it is also possible for the expansion element 14 to be opened at the inlet of the drive train cooler 15 in order to additionally absorb the waste heat of the electric drive components without evaporation heat. In this case, the refrigerant flow is split in parallel between the external heat exchanger 4 and the drive train cooler 15 after the heat is released in the water-cooled condenser 2.

[0096] Figure 9 A reheating circuit according to Figure 7 is shown, wherein the coolant heating is additionally used as heating device 24 in the heating circuit 34 in order to additionally heat the coolant to the desired target temperature.

[0097] In this mode, the air flowing into the cabin is first dehumidified and then heated to the desired temperature. The air is dehumidified while flowing through the evaporator 5. Downstream of the evaporator 5, the air is heated while flowing through the thermal energy heat exchanger 7.

[0098] In this case, the high-pressure side refrigerant flows via the water-cooled condenser 2. The connection 2 to 3 to the three-way expansion valve 3 between the heating condenser 2 and the external heat exchanger 4 is adjusted. In this case, the intermediate pressure level in the external heat exchanger 4 is set such that the temperature of the refrigerant in the external heat exchanger 4 corresponds to the ambient temperature. Due to the lack of temperature difference, there is no heat transfer between the refrigerant and the ambient air 29. In this way, neither heat is released to the ambient air 29 nor heat is taken from the ambient air 29.

[0099] Figure 10 A circuit for cabin heating is shown. In this case, the cabin is heated purely electrically.

[0100] In this mode, the air flowing into the cabin is heated via the thermal energy heat exchanger 7, because the coolant flowing through the thermal energy heat exchanger 7 is directly heated by the heating device 24. In this way, the heating capacity required for heating the cabin is provided purely electrically by the heating device 24.

[0101] By means of the heating device 24, the heating circuit 34 is operated by means of the coolant pump 27 and the thermal energy heat exchanger 7 for heating the cabin air. The battery heat exchanger 19 and the drive train cooler 16 operate in their coolant loops in parallel to each other without the external heat exchanger 4 being active.

[0102] Figure 11 A method for cabin heating using waste heat of drive train components is shown. In this case, the compressor 1 and the heating condenser 2 are connected via the bypass 12 to the expansion element 14, to the drive train cooler 15 and to the refrigerant collector 10. The condensation heat in the heating condenser 2 is released into the heating circuit 34 and the heating circuit 34 releases the condensation heat in the thermal energy heat exchanger 7 into the cabin air. As in the modes according to Figure 11 、 Figure 10 、 Figure 9 and Figure 7 , the battery heat exchanger 19 and the drive train cooler 16 operate in parallel and independently of each other.

[0103] In summary, in this mode, the air flowing into the cabin is heated via the thermal energy heat exchanger 7, as the condensation heat of the refrigerant is released into the coolant flowing through the thermal energy heat exchanger 7.

[0104] After releasing heat in the water-cooled condenser 2, the refrigerant flows back to the compressor 1 via the drive train chiller 15. In this way, the waste heat of the electric drive train is used as a heat source for the heat pump system. Thus, the water-heat pump functionality is used.

[0105] Figure 12 The heating of the vehicle cabin without active battery cooling using the refrigerant circuit is shown. The refrigerant is compressed in the compressor 1, at least partially condensed in the heating condenser 2 and then routed via the three-way expansion valve 3 to the external heat exchanger 4. Downstream of the heating condenser 2, the refrigerant is expanded in the three-way expansion valve 3 and absorbs heat from the ambient air 29 in the external heat exchanger 4 and then reaches the refrigerant collector 10 and finally the compressor 1 via the three-way expansion valve 8 in the bypass position by means of the bypass 13. Here, likewise, the battery heat exchanger 19 and the drive train cooler 16 are recirculated separately.

[0106] In summary, in this mode, the air flowing into the cabin is heated via the thermal energy heat exchanger 7, as the condensation heat of the refrigerant is released into the coolant flowing through the thermal energy heat exchanger 7.

[0107] After releasing heat in the water-cooled condenser 2, the refrigerant continues to flow through the three-way expansion valve 3. The connection 2 to 3 of the three-way expansion valve 3 between the water-cooled condenser 2 and the external heat exchanger 4 is adjusted such that in the external heat exchanger 4 the evaporation capacity of the refrigerant required for the heat pump operation can be absorbed from the ambient air 29. The refrigerant continues to flow to the battery chiller 9 to return to the compressor 1 via the bypass 13. Thus, the air heat pump functionality is used.

[0108] In the combined heat pump operation, the modes according to Figure 11 and Figure 12 are carried out simultaneously.

[0109] Figure 13Battery heating is shown to take place by means of the heating device 24. The heating device 24 within the heating circuit 34 heats the coolant, which in this case acts as a heat carrier, and this heat carrier reaches the indirect battery heating loop 32 via the three-way valve 31 to the indirect heat exchanger 11, where the heat is released into the secondary bypass circuit 35 and ultimately into the battery heat exchanger 19. The secondary bypass circuit 35 is recirculated via the coolant pump 20 and the first three-way valve 25 to the indirect heat exchanger 11 and the battery electronics cooler 33 and is cooled by the battery heat exchanger 19.

[0110] In this operating mode, the electrically driven cooling circuit 23 is operated independently thereof.

[0111] In summary, in this mode, the three-way valve 31 at the outlet of the thermal energy heat exchanger 7 is connected so that the coolant can flow through the indirect heat exchanger 11. According to its function, the indirect heat exchanger 11 is a coolant-coolant heat exchanger that transfers heat from the indirect battery heating loop 32 to the secondary bypass circuit 35. Prior to this, the coolant flowing through the indirect heat exchanger 11 is heated to the desired temperature by the heating device 24.

[0112] In the indirect heat exchanger 11, the heat required for heating the battery is transferred from the A / C coolant circuit to the battery coolant circuit. In the battery coolant circuit, the coolant flows only through the integrated electronics and battery heat exchanger 19 via the smaller secondary bypass circuit 35.

[0113] In Figure 14 , the battery heating is again connected via the heating circuit 34 and the indirect battery heating loop 32, wherein the refrigerant circuit instead of the heating device 24 is operated, and the condensation heat is fed into the heating circuit 34 via the heating condenser 2. The refrigerant is compressed in the compressor 1, condensed in the heating condenser 2 and routed via the bypass 12 to the expansion element 14 of the drive train chiller 15. As described above, the drive train chiller 15 absorbs the waste heat of the drive train cooler 16 and makes this waste heat available to the battery heat exchanger 19 via the refrigerant collector 10 and the compressor 1 and then via the heating condenser 2.

[0114] In summary, in this mode, the three-way valve 31 at the outlet of the thermal energy heat exchanger 7 is connected so that the coolant can flow through the indirect coolant-coolant heat exchanger 11. Prior to this, the coolant flowing through the indirect coolant-coolant heat exchanger 11 is heated to the desired temperature by the condensation heat of the refrigerant.

[0115] After the heat is released in the water-cooled condenser 2, the refrigerant flows back to the compressor 1 via the drive train chiller 15. In this way, the waste heat of the electric drive train is used as a heat source for the heat pump system. Thus, the water-heat pump function is used.

[0116] Finally, Figure 15 Battery heating is shown by additionally using the environmental heat of the ambient air 29. The refrigerant is compressed in the compressor 1, condensed in the heating condenser 2 and then expanded in the three-way expansion valve 3. In the external heat exchanger 4, the refrigerant absorbs heat from the ambient air 29 using evaporation. The evaporated refrigerant reaches the refrigerant collector 10 and the compressor 1 via the three-way expansion valve 8 and its bypass outlet via the bypass 13. Heat is supplied to the secondary bypass circuit 35 with the battery heat exchanger 19 via the indirect heat exchanger 11. Said heat is fed into the heating circuit 34 via the heating condenser 2 and reaches the indirect heat exchanger 11 via the indirect battery heating loop 32. The drive train cooler 16 is recirculated in the electric drive cooling loop 23 independently of the indirect battery heating loop 32.

[0117] In summary, in this mode, the three-way valve at the outlet of the thermal energy heat exchanger 7 is connected so that coolant can flow through the indirect coolant-coolant heat exchanger 11. Before that, the coolant flowing through the indirect coolant-coolant heat exchanger 11 is heated to the desired temperature by the condensation heat of the refrigerant.

[0118] After the heat is released in the water-cooled condenser 2, the refrigerant continues to flow through the three-way expansion valve 3. The connection 2 to 3 of the three-way expansion valve 3 between the water-cooled condenser 2 and the external heat exchanger 4 is adjusted so that in the external heat exchanger 4 the evaporation quantity of the refrigerant required for the heat pump operation can be absorbed from the ambient air. The refrigerant continues to flow to the battery chiller 9 to return to the compressor 1 via the bypass 13. Thus, the air heat pump function is used.

[0119] According to Figure 16 The refrigerant system circuit according to Figure 1 is a simplified version of the refrigerant system and heat pump circuit according to Figure 1 which is primarily designed to provide a higher cooling capacity at high ambient temperatures. Instead of the external heat exchanger in the circuit according to , an A / C condenser 37 with an active sub-cooling section and a collector are provided. The A / C condenser 37 is designed as a heat exchanger for releasing the condensation heat into the ambient air 29 and achieving a higher output than the external heat exchanger under the same boundary conditions. At the same time, in the case of the A / C condenser 37, there is no longer the function of the air heat pump to absorb heat from the ambient air. Therefore, in the heating operation, the refrigerant system circuit can only rely on the waste heat from the electrical and electronic drive components of the coolant circuit 17 as evaporation heat for the refrigerant. Due to the missing air heat pump function, it is also no longer necessary for the refrigerant to bypass the battery chiller.

[0120] Due to the reduced functionality, the refrigeration system circuit is less complex and requires fewer components than a refrigeration system and heat pump circuit according to Figure 1

[0121] Industrial applicability

[0122] The present invention relates to a heat pump arrangement with indirect battery heating for a battery electric motor vehicle.

[0123] The present invention also relates to a method of operating the heat pump arrangement in selected operating modes.

[0124] The field of application of the present invention is the field of electric vehicles that typically use high voltage batteries (HV batteries) as energy storage devices for supplying energy to the drivetrain of the vehicle.​

Claims

1. A heat pump arrangement for a battery-powered vehicle with indirect battery heating. - It has a refrigerant circuit, the refrigerant circuit having a compressor (1), a heating condenser (2), a first three-way expansion valve (3), an external heat exchanger (4), at least one evaporator (5) having an associated first expansion element (6) and a second three-way expansion valve (8) arranged in parallel with said evaporator (5), and a battery-operated cooler (9), wherein, -A first bypass (12) having a second expansion element (14) and a transmission system cooler (15) is arranged between the heating condenser (2) and the first three-way expansion valve (3), and -Having a coolant circuit (17), the coolant circuit (17) having a coolant cooler (18) and a battery heat exchanger (19) with an associated first coolant pump (20), and at least one drivetrain cooler (16) with an associated second coolant pump (21) arranged in parallel with the battery heat exchanger (19), wherein, -A battery temperature control loop (22) on the coolant side, comprising the battery heat exchanger (19), the first coolant pump (20), the first three-way valve (25), and the battery cooler (9), and -The electrically driven cooling loop (23) on the coolant side, comprising the drivetrain cooler (16), the second coolant pump (21), the second three-way valve (26), and the drivetrain cooler (15), is formed in the following manner: - This allows the battery temperature control loop (22) and the electric drive cooling loop (23) to operate as separate loops independently of each other and independently of the coolant loop (17), and - It has a heating circuit (34) having the heating condenser (2), a third coolant pump (27), a heating device (24), a heat exchanger (7), and an indirect battery heating loop (32) with an indirect heat exchanger (11), the indirect battery heating loop (32) being connectable via a third three-way valve (31), and - It has a secondary bypass circuit (35) as part of the coolant circuit (17), the secondary bypass circuit (35) having the battery heat exchanger (19), the first coolant pump (20), the first three-way valve (25) and the indirect heat exchanger (11).

2. The heat pump arrangement according to claim 1, characterized in that, The first three-way expansion valve (3) and the second three-way expansion valve (8) are configured to have expansion and bypass functions.

3. The heat pump arrangement according to claim 1 or 2, characterized in that, A heated condenser bypass (36) is arranged in the refrigerant circuit as a connection between the high-pressure outlet of the compressor (1) and the first three-way expansion valve (3).

4. The heat pump arrangement according to claim 1 or 2, characterized in that, A refrigerant collector (10) is arranged upstream of the compressor (1) in the refrigerant circuit.

5. The heat pump arrangement according to claim 1 or 2, characterized in that, A battery electronic device cooler (33) is arranged in the secondary bypass circuit (35).

6. The heat pump arrangement according to claim 1 or 2, characterized in that, The external heat exchanger (4) and the coolant cooler (18) are formed together in the cooler unit (30), wherein the external heat exchanger (4) is arranged downstream of the coolant cooler (18) along the flow direction of the ambient air (29).

7. The heat pump arrangement according to claim 1 or 2, characterized in that, A second bypass (13) is arranged in parallel with the battery cooler (9) in the refrigerant circuit.

8. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for active cooling of a vehicle cabin, characterized in that, The refrigerant downstream of the compressor (1) flows via the heated condenser bypass (36) and the first three-way expansion valve (3) to the external heat exchanger (4) which operates as a condenser, and then expands in the first expansion element (6) and evaporates in the evaporator (5), wherein the battery heat exchanger (19) allows the refrigerant to flow through the battery heat exchanger (19), and at the same time, the battery temperature control loop (22) and the secondary bypass loop (35) operate in parallel, and the refrigerant loop (17) is operated via the refrigerant cooler (18) and the drivetrain cooler (16) for passive cooling of the drivetrain.

9. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for active cooling of a vehicle battery, characterized in that, The refrigerant downstream of the compressor (1) flows via the heated condenser bypass (36) and the first three-way expansion valve (3) to the external heat exchanger (4) which operates as a condenser, and then expands in the second three-way expansion valve (8) and evaporates in the battery cooler (9), wherein the battery temperature control loop (22) is connected to the battery cooler (9), the battery heat exchanger (19) and in parallel to the battery electronics cooler (33) in the secondary bypass loop (35), and the coolant loop (17) is operated via the coolant cooler (18) and the drivetrain cooler (16) for passive cooling of the drivetrain.

10. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for passive cooling of a vehicle battery, characterized in that, The coolant circuit (17) is operated by the coolant cooler (18) and the battery heat exchanger (19) and the drivetrain cooler (16) in parallel for passive cooling, wherein the secondary bypass circuit (35) having the battery electronics cooler (33) operates in parallel.

11. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for passive cooling of a drivetrain, characterized in that, The coolant circuit (17) having the coolant cooler (18) and the transmission cooler (16) is operated for passive cooling, wherein the battery temperature control loop (22) having the battery heat exchanger (19) and the secondary bypass loop (35) having the battery electronics cooler (33) operate in parallel with each other and independently of the coolant circuit (17).

12. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for reheating a vehicle cabin, characterized in that, The refrigerant downstream of the compressor (1) flows via the heated condenser (2) and the first three-way expansion valve (3) to the external heat exchanger (4), which operates as a condenser or an evaporator, and then expands in the first expansion element (6) and evaporates in the evaporator (5). The battery heat exchanger (19) allows the refrigerant to flow through the battery heat exchanger (19), and at the same time, the battery temperature control loop (22) and the secondary bypass loop (35) operate in parallel, and the electric drive cooling loop (23) operates via the drive cooler (16), and the heating loop (34) operates via the heated condenser (2) and the heat exchanger (7).

13. The method of operating a heat pump arrangement for reheating a vehicle cabin according to claim 12, characterized in that, The heating device (24) also operates in the heating circuit (34).

14. The method of operating a heat pump arrangement for reheating a vehicle cabin according to claim 12 or 13, characterized in that, A portion of the refrigerant downstream of the heating condenser (2) flows via the first bypass (12) and expands in the second expansion element (14) and is evaporated in the drivetrain cooler (15) to additionally absorb waste heat from the drivetrain components.

15. The method of operating a heat pump arrangement for reheating a vehicle cabin according to claim 12 or 13, characterized in that, The intermediate pressure level in the external heat exchanger (4) is set in such a way that the temperature of the refrigerant in the external heat exchanger (4) corresponds to the temperature of the ambient air (29).

16. A method for operating a heat pump arrangement according to any one of claims 1 to 7 to heat the vehicle cabin using waste heat from the drivetrain, characterized in that, The refrigerant downstream of the compressor (1) flows via the heating condenser (2) and the first bypass (12), and then expands in the second expansion element (14) and evaporates in the drive cooler (15), wherein the battery heat exchanger (19) allows the refrigerant to flow through the battery heat exchanger (19), and simultaneously, the battery temperature control loop (22) and the secondary bypass loop (35) operate in parallel, and the electric drive cooling loop (23) operates via the drive cooler (16), and the heating loop (34) operates via the heating condenser (2) and the heat exchanger (7).

17. A method of operating a heat pump arrangement according to any one of claims 1 to 7 to heat a vehicle cabin using ambient heat, characterized in that, The refrigerant downstream of the compressor (1) flows through the heating condenser (2) to the first three-way expansion valve (3) and expands and evaporates in the external heat exchanger (4), wherein the battery heat exchanger (19) allows the coolant to flow through the battery heat exchanger (19), and at the same time, the battery temperature control loop (22) and the secondary bypass loop (35) operate in parallel, and the electric drive cooling loop (23) is operated through the transmission cooler (16), and the heating loop (34) is operated through the heating condenser (2) and the heat exchanger (7).

18. A method of operating a heat pump arrangement according to any one of claims 1 to 7 for indirect heating of a battery, characterized in that, The heating circuit (34) is heated to the desired temperature by the heating device (24) and connected to the indirect heat exchanger (11) via the third three-way valve (31), wherein the heating condenser (2) and the thermal energy heat exchanger (7) are not in operation, and the secondary bypass circuit (35) is connected to the battery heat exchanger (19) and the indirect heat exchanger (11), and the electric drive cooling circuit (23) is operated via the transmission cooler (16).

19. The method for operating a heat pump arrangement according to claim 18 to indirectly heat a battery using waste heat from the drive system, characterized in that, The refrigerant downstream of the compressor (1) flows via the heated condenser (2) and the first bypass (12), and then expands in the second expansion element (14) and evaporates in the drive system refrigerator (15), wherein the heating device (24) is not operated.

20. The method for operating a heat pump arrangement according to claim 18 to indirectly heat a battery using ambient heat, characterized in that, The refrigerant downstream of the compressor (1) flows through the heating condenser (2) to the first three-way expansion valve (3), expands and evaporates in the external heat exchanger (4), and then flows back to the compressor (1) through the second three-way expansion valve (8), wherein the heating device (24) is not operated.

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