Thermal system for a battery powered vehicle and method for said system

Abstract

A thermal system for a vehicle having an electric drive battery (2) and a passenger compartment (3), comprising a first cooling circuit (10) with a first coolant, a second cooling circuit (20) with a second coolant, the second coolant being propane or a coolant that puts the health of the passengers at risk, and the first coolant being a different coolant from the second coolant, in particular a water-glycol mixture, wherein the first cooling circuit (10) has a first heat exchanger (WT1) at the drive battery (2), a second heat exchanger (WT2) for the passenger compartment (3), a third heat exchanger (WT3) for the environment (4) and a fourth heat exchanger (WT4) for the second cooling circuit (20), in order to exchange heat or cold, wherein the second cooling circuit (20) at the fourth heat exchanger (WT4) is in the form of an evaporator in order, at the fourth heat exchanger (WT4), to permit lowering of a temperature of the first coolant below the ambient temperature, and a first valve arrangement (5), which is arranged between the first cooling circuit (10) and the second cooling circuit (20) and is designed to connect the first heat exchanger (WT1) to the third heat exchanger (WT3) or the first heat exchanger (WT1) to the fourth heat exchanger (WT4), and wherein the first valve arrangement (5) is furthermore designed to connect the second heat exchanger (WT2) for the passenger compartment (3) to the fourth heat exchanger (WT4) for the second cooling circuit (20), in order to cool air in the passenger compartment (3) of the vehicle.

Description

[0001] Description

[0002] title

[0003] Thermal system for a battery-powered vehicle and method therefor

[0004] State of the art

[0005] The present invention relates to a thermal system for a vehicle having an electric drive battery and an interior for passengers with an improved and simplified architecture for the thermal system and a method for performing thermal management.

[0006] In addition to an electric drive, electrically powered vehicles have, in particular, an electric drive battery that supplies the electric drive with energy. However, compared to vehicles with conventional internal combustion engines, thermal management in electrically powered vehicles is fundamentally different. In particular, a thermal system in an electrically powered vehicle must provide coolants with different temperature levels, for example, for the drive battery, the electrically driven axle, and the vehicle interior. The electric drive battery, in particular, must be operated within a comfortable temperature range so that, for example, during a cold start of the vehicle, the battery first needs to be heated and then cooled after a short time when the battery warms up.The same applies to the vehicle interior, which needs to be cooled at high outside temperatures and heated at low outside temperatures. Overall, this leads to a certain complexity in the thermal system of a battery-powered vehicle. Improvements and simpler architectures would therefore be desirable.

[0007] Disclosure of the Invention The thermal system according to the invention for a vehicle with an electric drive battery and an interior for passengers with the features of claim 1 has the advantage that the design and manufacture of the thermal system can be significantly simplified. In particular, it is possible to use a reduced number of pumps, valves, and lines, so that on the one hand the investment costs for the thermal system according to the invention can be reduced and on the other hand a considerable weight saving can be achieved through reduced line lengths and a reduced number of components. Furthermore, the thermal system according to the invention enables safe operation of all systems, in particular the electric drive battery. The thermal system can also be divided into several modules, which can be prefabricated as assemblies and then assembled together in a vehicle.

[0008] This is achieved according to the invention in that the thermal system comprises a first cooling circuit with a first coolant and a second cooling circuit with a second coolant. The second coolant is propane or a coolant that is hazardous to the health of the occupants, and the first coolant is a different coolant than the second coolant, e.g. water, glycol, oil, or a mixture or the like. The first cooling circuit has at least four heat exchangers. The first cooling circuit has a first heat exchanger WT1 on the drive battery, a second heat exchanger WT2 to the interior, a third heat exchanger WT3 to the environment, and a fourth heat exchanger WT4 to the second cooling circuit. The second cooling circuit is designed as an evaporator on the fourth heat exchanger WT4 in order to reduce the temperature of the first coolant at the fourth heat exchanger WT4.The thermal system further comprises a first valve arrangement arranged in the first cooling circuit. The first valve arrangement is configured to connect or disconnect the first heat exchanger WT1 with the third heat exchanger WT3 or the first heat exchanger WT1 with the fourth heat exchanger WT4. This allows different heating / cooling strategies to be implemented. Furthermore, the second heat exchanger is connected to the fourth heat exchanger via the first valve arrangement.

[0009] Thus, by using two cooling circuits, the thermal system according to the invention can prevent a cooling circuit operated with propane or another coolant that is hazardous to the health of the occupants from coming into direct contact with the interior of the vehicle. The second cooling circuit is designed, in particular, as a heat pump circuit. Thus, propane, for example, can be used as the coolant for the second cooling circuit, and the second cooling circuit can be arranged in a crash-safe position in the vehicle. Thus, temperature control of various components of the vehicle can be achieved while allowing a minimal number of pumps and valves and minimal line lengths.

[0010] In particular, the incompressibility of the first coolant can also be used to transfer coolant from a high-temperature range, in particular 65°C to 85°C, into the drive battery, in particular a high-voltage battery, operating at a medium temperature level, in particular 20°C to 45°C. This applies in particular to an internal hydraulic release of the first cooling circuit to a fourth heat exchanger WT4 of the second cooling circuit, used as a cooler.

[0011] The subclaims show preferred developments of the invention.

[0012] Preferably, the first valve arrangement is configured to simultaneously connect the first heat exchanger WT1 to the third heat exchanger WT3 and the fourth heat exchanger WT4. This allows a mixed temperature to be generated, preferably by simultaneously connecting the first heat exchanger WT1 to the third and fourth heat exchangers. Furthermore, heat absorbed via the third heat exchanger WT3 can also be transferred to the second cooling circuit via the fourth heat exchanger WT4.

[0013] Preferably, the first valve arrangement is configured such that the second heat exchanger WT2 to the interior can only be connected to the fourth heat exchanger WT4 to the second cooling circuit, or the connection is closed. When the second and fourth heat exchangers are connected to each other, the coolant exiting the fourth heat exchanger WT4 can be used in the first cooling circuit to cool the interior via the second heat exchanger WT2.

[0014] Particularly preferably, the thermal system further comprises a first

[0015] Subcircuit of the first cooling circuit, in which the first heat exchanger WT1 for the drive battery and the third heat exchanger WT3 for the environment, as well as a first pump P1, are located. Thus, the first subcircuit allows direct cooling of the battery by ambient air via the third heat exchanger WT3.

[0016] The thermal system further preferably comprises a second sub-circuit of the first cooling circuit, in which the second heat exchanger WT2 is arranged to the interior and the fourth heat exchanger WT4 to the second cooling circuit and a second pump P2. The interior can be cooled via the second sub-circuit via the second heat exchanger WT2.

[0017] Furthermore, the first valve arrangement is arranged such that the first valve arrangement connects the first and second partial circuits. The first valve arrangement can preferably connect the drive battery to the fourth heat exchanger WT4 to the second cooling circuit, so that the fourth heat exchanger WT4 can be used as a heat sink and the coolant from the first cooling circuit can be cooled and returned to the drive battery. The first coolant can be pumped in the second partial circuit, in particular, by means of the first pump P1.

[0018] The first valve arrangement can further connect the third heat exchanger WT3 of the first sub-circuit to the fourth heat exchanger WT4 of the second cooling circuit to supply heat from the environment to the second cooling circuit. The first coolant can be pumped in the second sub-circuit, in particular by means of the second pump P2, while the first pump P1 can supply coolant to the battery from another sub-circuit that is not part of the first or second sub-circuit.

[0019] Furthermore, a check valve is preferably arranged in the second partial circuit between the second heat exchanger WT2 to the interior and the fourth heat exchanger WT4 to the second cooling circuit. The check valve prevents unwanted backflow to the second heat exchanger WT2 if, for example, the drive battery is connected to the fourth heat exchanger to the second cooling circuit via the first valve arrangement. Further, the thermal system preferably comprises a fifth heat exchanger WT5 to the power electronics and / or to an electric axle. The power electronics is, in particular, power electronics for the drive battery and / or for electric machines. The power electronics usually must be cooled during vehicle operation. Furthermore, the thermal system preferably comprises a sixth heat exchanger WT6 for heating the interior. The sixth heat exchanger WT6 thus provides vehicle heating.The thermal system further preferably comprises a seventh heat exchanger WT7 for the second cooling circuit, wherein heat from the second cooling circuit can be introduced into the first cooling circuit via the seventh heat exchanger WT7. The thermal system further preferably comprises an eighth heat exchanger WT8 for the environment. The eighth heat exchanger WT8 is connected in particular to the fifth heat exchanger WT5 for the power electronics.

[0020] The thermal system further comprises a third sub-circuit of the first cooling circuit, in which the fifth heat exchanger WT5 for the power electronics and the eighth heat exchanger WT8 for the environment, as well as a third pump P3, are located. This allows the power electronics to be cooled, for example, by the ambient air.

[0021] The thermal system further preferably comprises a fourth sub-circuit of the first cooling circuit, in which the sixth heat exchanger WT6 for the interior, in particular for heating the interior, and the seventh heat exchanger WT7 for the second cooling circuit, in particular for heating the fourth sub-circuit, as well as a fourth pump P4, are arranged. The fourth sub-circuit can, for example, be used to heat the interior of the vehicle using waste heat from the second cooling circuit.

[0022] According to a particularly preferred embodiment of the invention, the thermal system further comprises a second valve arrangement which connects or disconnects the third sub-circuit with the fourth sub-circuit. The second valve arrangement is preferably a 4 / 3-way valve. The second valve arrangement connects, in particular, a line section from the seventh heat exchanger WT7 to the sixth heat exchanger WT6 with a line section of the third sub-circuit from the fifth heat exchanger WT5 to the eighth heat exchanger WT8. This allows, for example, waste heat from the power electronics to be used to heat the interior. Heat from the second cooling circuit, which is absorbed into the fourth sub-circuit via the seventh heat exchanger WT7, can also be guided to the eighth heat exchanger WT8 and thus released to the environment via the eighth heat exchanger WT8.

[0023] According to a further preferred embodiment of the invention, the thermal system further comprises a third valve arrangement, which connects or separates the third subcircuit and the first subcircuit. The third valve arrangement is preferably a 3 / 4-way valve. The third valve arrangement allows, for example, waste heat from the power electronics, which can occur very quickly during operation, to be used to heat the drive battery.

[0024] Particularly preferably, the first valve arrangement is designed as a 5 / 8-way valve. Thus, the first valve arrangement has five ports and eight positions. The first valve arrangement can have a very compact design. In particular, the first valve arrangement can thus interconnect the first heat exchanger WT1 to the drive battery, the second heat exchanger WT2 to the interior of the vehicle as a cooler, the fourth heat exchanger WT4, which functions as a cooler for the second cooling circuit, and the third heat exchanger WT3 to the environment.

[0025] The first valve arrangement is preferably a proportional valve, so that in particular a mixture of colder and warmer first coolant of the first cooling circuit is also possible.

[0026] The first valve arrangement is further preferably divided into two subvalves, more preferably into three subvalves, in particular two 3 / 3-way valves and one 2 / 2-way valve. Alternatively, the first valve arrangement is designed as a 5 / 5-way valve with five ports and five positions.

[0027] The thermal system preferably comprises exactly four pumps. Preferably, only one pump is arranged in each of the four sub-circuits of the first cooling circuit. The pumps preferably each have their own drive, or alternatively, two or more pumps can be operated via a common drive. One advantage of having their own drives on the pumps is that the pumps can be switched on or off as needed, thereby increasing the efficiency of the thermal system.

[0028] Further preferably, the third ambient heat exchanger WT3 and the eighth ambient heat exchanger WT8 are arranged in a common, but hydraulically split cooler. This allows for a compact cooler design while still allowing two separately operable subcircuits to be implemented in the split cooler. In particular, only two hydraulically separated submodules can be implemented in one ambient cooler.

[0029] The split cooler preferably also allows a separation between low-temperature cooling and high-temperature cooling for the first cooling circuit of the thermal system.

[0030] Further preferably, the thermal system is configured to supply heat from the seventh heat exchanger WT7 and / or heat from the fifth heat exchanger WT5 to the sixth heat exchanger WT6 in order to heat an interior of the vehicle via the sixth heat exchanger WT6. Thus, the second cooling circuit can be operated as a heat pump circuit, and heat from the first cooling circuit can be absorbed at the seventh heat exchanger WT7 and transferred to the sixth heat exchanger WT6 to heat the interior.

[0031] Preferably, the thermal system is further configured to connect the third heat exchanger WT3 and / or the fourth heat exchanger WT4 to the second heat exchanger WT2 to the vehicle interior in order to cool the vehicle interior. Thus, heat absorbed at the vehicle's radiator can be supplied to the fourth heat exchanger WT4 and released therefrom to the second cooling circuit. As a result, the coolant in the second subcircuit is cooled at the fourth heat exchanger WT4 and can be supplied to the second heat exchanger WT2 to cool the vehicle interior.

[0032] According to a further preferred embodiment of the invention, the thermal system is configured to supply heat from the seventh heat exchanger WT7, which can be absorbed from the second cooling circuit 2, to the first heat exchanger WT1 in order to heat the electric drive battery.

[0033] More preferably, the third heat exchanger WT3 on the radiator has an inlet which is connected to the first valve arrangement and an outlet which is connected to the first pump P1 in the first partial circuit. The first valve arrangement is designed to connect the inlet of the third heat exchanger to the second pump in the second partial circuit in order to supply heat from the radiator via the third heat exchanger WT3 to the fourth heat exchanger WT4. In this case, a flow direction in the radiator is reversed, with the second pump P2 being operated in this position of the first valve arrangement. The heat absorbed via the radiator can thus be transferred to the second cooling circuit at the fourth heat exchanger WT4 and the second cooling circuit can be operated as a heat pump in order to then introduce the heat back into the first cooling circuit at a higher temperature level via the seventh heat exchanger WT7.Preferably, by increasing a temperature in the fourth sub-circuit, additional heat can also be supplied to the sixth heat exchanger WT6 in order to enable heating of the interior of the vehicle.

[0034] Further preferably, the thermal system is configured to operate the first pump P1 and the second pump P2 simultaneously. This allows the electric drive battery to be heated or cooled, while simultaneously cooling the interior of the vehicle.

[0035] Preferably, the first sub-circuit is directly connected to the second sub-circuit by means of a first direct connection. Thus, there is always a direct fluid connection without a shut-off device between the first and second sub-circuits. This makes it possible for either the first pump to be operated in the first sub-circuit or the second pump to be operated in the second sub-circuit and, by connecting via the first valve arrangement, for there to still be a flow of coolant in the respective circuit in which the pump is stationary. This contributes in particular to efficient energy use. The first direct connection preferably serves as a flow connection from the second sub-circuit to the first sub-circuit. More preferably, the first sub-circuit is also directly connected to the third sub-circuit via a second direct connection without a shut-off device.This allows either the first pump P1 or the third pump P3 to be operated and, if one of the pumps stops, a coolant flow can still be enabled in the respective sub-circuit.

[0036] The thermal system preferably has a further sub-circuit for one electric axle of the vehicle or two further sub-circuits for two electric axles of the vehicle.

[0037] Further preferably, all pumps of the thermal system and all valve arrangements of the thermal system are arranged in a common submodule.

[0038] In conjunction with the respective pump speed, the first valve arrangement preferably enables a continuous mixing of cold and warm first coolant in order to ensure precise conditioning and regulation of required supply and return temperatures, in particular to the interior of the vehicle and / or to the drive battery.

[0039] Thus, according to the invention, a thermal system with an optimal arrangement and a minimal number of heat exchangers, pumps, and valves can be achieved, which provides both cold and heat with maximum thermal efficiency to subsystems such as an interior, a drive battery, electrically driven axles, power electronics, etc. This also allows, in particular, a vehicle's range to be maintained through optimal thermal conditions for the drive battery, particularly in a temperature range of 20 °C to 45 °C.

[0040] Furthermore, the present invention relates to an electrically driven vehicle with a thermal system according to the invention.

[0041] Preferably, the present invention also relates to a method for carrying out thermal management of an electric vehicle by means of a thermal system according to the invention.

[0042] Brief Description of the Drawings Preferred embodiments of the invention are described in detail below with reference to the accompanying drawings. In the drawing:

[0043] Figure 1 is a schematic representation of a thermal system according to a first preferred embodiment of the invention,

[0044] Figure 2 is an enlarged partial view of the thermal system of Figure 1 in a preferred mode of operation,

[0045] Figure 3 is a schematic partial view of the thermal system of Figure 1 in a further preferred mode of operation,

[0046] Figure 4 is a schematic representation of a first valve arrangement of the thermal system of the first embodiment,

[0047] Figure 5 is a schematic representation of a second valve arrangement of the thermal system of the first embodiment,

[0048] Figure 6 is a schematic representation of a third valve arrangement of the thermal system of the first embodiment, and

[0049] Figure 7 is a schematic representation of a first valve arrangement according to a second embodiment of the invention.

[0050] Preferred embodiments of the invention

[0051] A thermal system 1 and a method for carrying out thermal management of an electric vehicle according to a preferred first embodiment of the invention are described in detail below with reference to Figures 1 to 6.

[0052] The thermal system 1 provides a cooling and / or heating power requirement for individual components of the electrically powered vehicle. The individual components are, for example, an electric drive battery 2, a vehicle interior 3, power electronics 9, and / or electric axles of the vehicle. The power electronics 9 can be configured to control the drive battery 2 and / or other electrical machines, e.g., electric drives of the vehicle.

[0053] The thermal system further comprises a first cooling circuit 10 with a first coolant and a second cooling circuit 20 with a second coolant. The first cooling circuit 10 is hydraulically separated from the second cooling circuit 20. The second coolant of the second cooling circuit 20 is, for example, propane or a coolant hazardous to the health of occupants, and the first coolant is a different coolant than the second coolant. The first coolant is, for example, a water-glycol mixture.

[0054] This design, in which the second coolant may be a coolant that endangers the health of the vehicle's occupants, allows the second cooling circuit 20 to be arranged in the vehicle with the greatest possible protection, particularly in the event of an accident or the like. Furthermore, there is no contact between the second coolant and the vehicle's interior 3, since the first cooling circuit 10 is always connected between the second cooling circuit 20 and the interior 3. This means that even in the event of a leak in the second cooling circuit, for example, there is no immediate danger to the vehicle's occupants.

[0055] The second cooling circuit 20 is a cooling circuit of a heat pump with a compressor 21, an expansion valve 22 and two heat exchangers 23, 24. The coolant of the second cooling circuit 20 extracts heat from the coolant of the first cooling circuit 10 by evaporating the coolant of the second cooling circuit 20 and transfers heat to the coolant of the first cooling circuit 10 by condensing the coolant of the second cooling circuit 20.

[0056] The second cooling circuit 20 is designed to provide cold and / or heat for the thermal system 1 in certain operating situations.

[0057] The thermal system 1 is further configured such that the first cooling circuit 10 includes a first heat exchanger WT1 connected to the drive battery 2, a second heat exchanger WT2 connected to the interior 3, a third heat exchanger WT3 connected to the environment, and a fourth heat exchanger WT4 connected to the second cooling circuit, which is a submodule 23. Thus, the temperature of the first coolant of the first cooling circuit 10 can be lowered at the fourth heat exchanger WT4.

[0058] The thermal system 1 further comprises a first valve arrangement 5, which is arranged between a first sub-circuit 11 of the first cooling circuit 10 and a second sub-circuit 12 of the first cooling circuit 10. The first valve arrangement 5 is configured to connect the first heat exchanger WT1, which is arranged in the first sub-circuit, to the third heat exchanger WT3, which is also arranged in the first sub-circuit 11, or to connect the first heat exchanger WT1 of the first sub-circuit 11 to the fourth heat exchanger WT4, which is arranged in the second sub-circuit 12.

[0059] The first valve arrangement 5 is further configured to connect the third heat exchanger WT3, which is arranged in the first sub-circuit 11, to the fourth heat exchanger WT4, which is arranged in the second sub-circuit 12.

[0060] The first valve arrangement 5 is further configured to connect the second heat exchanger WT2, which is arranged in the second sub-circuit 12, to the fourth heat exchanger WT4 in the second sub-circuit 12 in order to cool and / or dehumidify interior air in the interior 3 of the vehicle.

[0061] In other words, the first cooling circuit comprises the first sub-circuit 11 and the second sub-circuit 12, which can be connected or separated in different constellations via the valve arrangement 5.

[0062] As shown in Figure 4, the first valve assembly 5 is a 5 / 8-way valve, i.e. a valve with five ports and eight positions.

[0063] Figure 4 shows a schematic representation of the first valve arrangement 5. The eight positions of the first valve arrangement 5 are designated 8.1, 8.2, 8.3, 8.4, 8.5, 8.6, 8.7, and 8.8. Below the equivalent circuit diagrams of the valve positions, the letters A, B, C, D, and E represent the respective operating states in the thermal system 1. These letters represent: A no cooling at heat exchanger WT2 B cooling at heat exchanger WT2

[0064] C no cooling on heat exchanger WT2

[0065] D Cooling of the drive battery 2 at the first heat exchanger WT1

[0066] E Heat pump operation by providing ambient heat from the third heat exchanger WT3 to the fourth heat exchanger WT4.

[0067] As can be further seen from Figure 1, the first subcircuit 11 contains the first heat exchanger WT1 leading to the drive battery 2, the third heat exchanger WT3 leading to the environment 4, and a first pump P1. In normal operating conditions, the first pump P1 conveys coolant through the heat exchanger WT1 and typically absorbs heat from the drive battery 2, which is then conducted to the third heat exchanger WT3, where it is released to the environment 4 via a radiator 8. The radiator 8 is preferably a vehicle radiator.

[0068] The second subcircuit 12 contains the second heat exchanger WT2 leading to the interior 3, the fourth heat exchanger WT4 leading to the second cooling circuit 20, and a second pump P2. During normal operation, the second pump P2 conveys coolant from the pump P2 to the fourth heat exchanger WT4. The coolant is cooled by the second cooling circuit 20 and then fed to the second heat exchanger WT2 to cool and / or dehumidify the interior 3 of the vehicle.

[0069] The first valve arrangement 5 is now arranged, as shown in Figure 1, in the line section of the first sub-circuit 11 between the first heat exchanger WT1 and the third heat exchanger WT3, and in the second sub-circuit 12 between the second heat exchanger WT2 and the fourth heat exchanger WT4. A bypass of the second pump P2 is also possible here.

[0070] Furthermore, a first direct connection 15 is provided between the first subcircuit 11 and the second subcircuit 12, in which a direct fluid exchange between the first and second subcircuits 11, 12 is possible. No shut-off device or the like is arranged in the first direct connection 15.

[0071] The thermal system 1 further comprises a third subcircuit 13 and a fourth subcircuit 14. The third subcircuit 13 contains the fifth heat exchanger WT5 for the power electronics 9, the eighth heat exchanger WT8 in the radiator 8 for the environment 4, and a third pump P3. The fourth subcircuit 14 contains the sixth heat exchanger WT6 for the vehicle interior 3, the seventh heat exchanger WT7 for the second cooling circuit 20, and a fourth pump P4. The seventh heat exchanger is part of the submodule 23.

[0072] Furthermore, a second valve arrangement 6 is provided between the third subcircuit 13 and the fourth subcircuit 14. The second valve arrangement 6 is a 4 / 3-way valve with four ports and three positions (see Figure 5).

[0073] Furthermore, a third valve arrangement 7 is arranged between the third subcircuit 13 and the first subcircuit 11. The third valve arrangement 7 is a 3 / 4-way valve with three ports and four positions (see Figure 6). The third valve arrangement 7 is connected to the first subcircuit 11 via a connecting line 18.

[0074] Furthermore, a second direct connection 16 is provided between the first sub-circuit 11 and the third sub-circuit 13. No shut-off valve or the like is arranged in the second direct connection 16, so that in every operating state, a fluid connection is always present between the first sub-circuit 11 and the third sub-circuit 13. The second direct connection 16 connects a line section of the first sub-circuit 11 between the first heat exchanger WT1 and the third heat exchanger WT3 upstream of the first valve arrangement 5 with a line section in the third sub-circuit 13 between the eighth heat exchanger WT8 and the third pump P3 upstream of the third pump P3.

[0075] Furthermore, a reservoir 17 is provided for the first coolant, which is connected to the first cooling circuit 10 via the second direct connection 16. Thus, each of the four subcircuits 11, 12, 13, 14 has its own separate pump P1, P2, P3, P4. Each subcircuit 11, 12, 13, 14 has only one pump P1, P2, P3, P4.

[0076] Furthermore, each sub-circuit 11, 12, 13, 14 has exactly two heat exchangers.

[0077] Thus, a particularly compact thermal system 1 with a simple basic structure can be realized.

[0078] Furthermore, the four pumps P1, P2, P3, P4 and the three valve arrangements 5, 6, 7 form a compact submodule 90. The submodule 90 has four connections for each subcircuit 11, 12, 13, 14.

[0079] To further improve compactness, the radiator 8 is constructed such that the third heat exchanger WT3 and the eighth heat exchanger WT8 are arranged in a common radiator housing, but are hydraulically separated there. Thus, the radiator 8 has a first partial radiator 81 and a second partial radiator 82. As shown in Figure 1, the radiator 8 has two connections for the first partial circuit 11 and two connections for the third partial circuit 13.

[0080] The thermal system 1 can now set the desired temperature levels at the eight heat exchangers according to the desired requirements. In particular, the thermal system 1 according to the invention allows for mixing of cold and warm refrigerant in the first subcircuit 11. This allows mixed temperatures to be created in order to set the most precise temperature specifications for the respective consumers.

[0081] The thermal system 1 can now be operated in the following operating situations with different thermal management procedures.

[0082] As shown, for example, in Figure 2, which is a section of the thermal system 1 of Figure 1 with the first and second sub-circuits 11, 12, the second heat exchanger WT2 can be connected to the fourth heat exchanger WT4 via the second pump P2. The coolant of the second sub-circuit 12 is then cooled in the fourth heat exchanger WT4 and fed directly back to the second heat exchanger WT2. This allows the interior 3, which is connected to the second heat exchanger WT2, to be cooled. This enables air conditioning and, if necessary, dehumidification of the interior 3, independent of the other sub-circuits of the first and second cooling circuits. The valve arrangement 5 can be located in positions 8.3 or 8.7. This is indicated in Figure 4 by the letter B.

[0083] At the same time, as can be seen from Figure 2, independent operation in the first subcircuit 11 can also be realized for independent operation in the second subcircuit 12. In this case, the first valve arrangement 5 is located in position 8.5, so that the electric drive battery 2 can be cooled by ambient air through the third heat exchanger WT3 on the radiator 8.

[0084] If no cooling is required in the interior 3 of the vehicle, the first valve arrangement 5 can be set to one of the positions 8.1, 8.2, or 8.8. Cooling of the interior is also prevented if the pump P2 is not operated in positions 8.3 to 8.7 of the first valve arrangement. Positions 8.1 and 8.8 of the first valve arrangement primarily serve the purpose of completely shutting off the heat exchanger WT1 of the battery 2 from the heat exchangers WT3 and WT4 in order to force a recirculation coolant flow exclusively via the 3 / 4 valve 7 when the pump P1 is operating.

[0085] In order to prevent a backflow of coolant in the second partial circuit 12 to the second heat exchanger WT2 in positions 8.3 and 8.4 of the first valve arrangement, a check valve 33 is arranged between the first valve arrangement 5 and the second heat exchanger WT2, as shown in Figures 1 and 2.

[0086] In a further preferred operating mode (see Figure 3), the first valve arrangement 5 is configured to simultaneously connect the first heat exchanger WT1 of the drive battery 2 to the third heat exchanger WT3 on the radiator 8 and the fourth heat exchanger WT4 for connection to the second cooling circuit 20. The first valve arrangement 5 is then located in position 8.4 shown in Figure 4 (see arrows in Figure 3). The first valve arrangement 5 can be switched to position 8.2 or 8.3, so that the heated coolant emerging from the first heat exchanger WT1 is completely conveyed back into the second sub-circuit 12, where the heat is transferred to the second cooling circuit 20 via the fourth heat exchanger WT4.

[0087] The coolant cooled by the second cooling circuit 12 from the fourth heat exchanger WT4 is returned to the first sub-circuit 11 via the first direct connection 15 by operating the first pump P1 and conveyed to the first heat exchanger WT1 to cool the drive battery 2. If the first valve arrangement 5 is in position 8.5, the coolant exiting the first heat exchanger WT1 flows completely into the third heat exchanger WT3 on the radiator, where it releases the heat previously absorbed in the first heat exchanger WT1 to the environment 4. Depending on the ambient temperature and ambient air density, the operating mode of the thermal system 1 is selected for a specific valve position of the first valve arrangement 5 and also ensures mixing of coolant that has been cooled to different degrees or that has simply been recirculated. This regulates both the flow and return temperatures of the drive battery 2 and controls the temperature of the drive battery 2.

[0088] Furthermore, an operating method - so-called heat pump operation - can also be implemented in which heat is absorbed from the environment 4 via the heat exchanger WT3 and transferred in the heat exchanger WT4 to the coolant of the second cooling circuit 20. Here, the direction of flow in the third heat exchanger WT3 of the radiator 8 is reversed. This means that an inlet 31 on the third heat exchanger WT3 becomes the outlet and an outlet 32 ​​on the third heat exchanger WT3 becomes the inlet. The designations inlet 31 and outlet 32 ​​refer to normal operation in which, for example, when the vehicle is moving, the drive battery 2 can be cooled by the radiator or by airflow on the third heat exchanger WT3 and operation of the first pump P1 without operating the heat pump (second cooling circuit 20).

[0089] If the flow direction in the third heat exchanger WT3 is to be reversed, the second pump P2 is operated, so that due to a connection between a second connection A2 and a third connection A3 of the first valve arrangement 5, coolant is drawn from the third heat exchanger WT3 and pumped to the fourth heat exchanger WT4. From the fourth heat exchanger WT4, the coolant can then be connected to the first sub-circuit 11 via the first direct connection 15 and flow back into the third heat exchanger WT3, where it can be reheated. As a result, heat from the environment 4 can be introduced into the second cooling circuit 20 via the fourth heat exchanger WT4 (heat pump operation) and discharged to the coolant of the first cooling circuit via the seventh heat exchanger WT7 and brought from the sixth heat exchanger WT6 to heat the interior 3 via the fourth pump P4 in the fourth sub-circuit 14.

[0090] The connections in the first valve arrangement 5 are designated by reference symbols A1, A2, A3, A4, and A5 in Figures 2 and 4. For clarity, these are only indicated in Figure 4 in the circuit diagram at position 8.1. In the other positions, the connections are as shown in the first circuit diagram in Figure 4.

[0091] A further operating method of the thermal system 1 can be realized if the first valve arrangement 5 is connected such that the first subcircuit 11 and the second subcircuit 12 are connected to one another, so that the first pump P1 generates a coolant flow through the first heat exchanger WT1 and the third heat exchanger WT3 on the radiator 8, and the second pump P2 in the second subcircuit 12 generates a coolant flow through the second heat exchanger WT2 and the fourth heat exchanger WT4 to cool and / or dehumidify the interior. Both the first pump P1 and the second pump P2 operate simultaneously.

[0092] Figure 5 schematically shows the second valve arrangement 6. Three positions of the second valve arrangement are designated by the designations 3.1, 3.2, and 3.3. Below the equivalent circuit diagram of the valve positions, the letters F, G, H, I, J, K, and L represent the respective operating states in the thermal system 1. The following meanings apply:

[0093] F Heating the interior with heat from the seventh heat exchanger WT7 G Heating the interior with heat from the fifth heat exchanger WT5 H Heating the battery with heat from the fifth heat exchanger WT5 I Heating the power electronics 9 in all valve positions

[0094] J Cooling the power electronics 9 with the eighth heat exchanger WT8 K Cooling the power electronics 9 with the sixth heat exchanger WT6 L Cooling the seventh heat exchanger WT7 with the sixth heat exchanger WT6 or eighth heat exchanger WT8.

[0095] The connections of the second valve arrangement 6 are designated A1, A2, A3 and A4.

[0096] Figure 6 shows the third valve arrangement 7 schematically. Four positions of the third valve arrangement are designated by the designations 4.1, 4.2, 4.3, and 4.4. Below the equivalent circuit diagram, the letters M, N, O, P, Q, R, and S represent the respective operating states in the thermal system 1. Here, M stands for battery heating and bypass.

[0097] N Maximum cooling of the battery with the third heat exchanger WT3 and the eighth heat exchanger WT8

[0098] O Heating the power electronics

[0099] P Cooling the power electronics with the eighth heat exchanger WT8 Q Heat from the seventh heat exchanger WT7 to battery 2 R Maintaining a battery temperature by cooling / heating

[0100] S Cooling the battery with the third heat exchanger WT3

[0101] The connections of the third valve arrangement 7 are labeled A1, A2 and A3.

[0102] A further operating method of the thermal system 1 can be carried out when heat from the seventh heat exchanger WT7 (position 3.1 in Figure 5), which is provided by the second cooling circuit 20, which is designed as a heat pump, and / or heat from the fifth heat exchanger WT5, which is waste heat from the power electronics 9 or the electric axles, is supplied to the sixth heat exchanger WT6 (position 3.2 or 3.3 in Figure 5). Preferably, both the third pump P3 and the fourth pump P4 can be operated, and the second valve arrangement 6 is connected such that a connection is established between the fifth heat exchanger WT5 and the sixth heat exchanger WT6 and a connection is established between the seventh heat exchanger WT7 and the sixth heat exchanger WT6 (position 3.2 in Figure 5). This allows rapid heating of the interior 3 of the vehicle, particularly using the seventh heat exchanger WT7.Further preferred is an operating method such that heat from the seventh heat exchanger WT7, which originates from the second cooling circuit 20, can be supplied to the first heat exchanger WT1 in order to heat the electric drive battery 2. This is necessary, for example, during a cold start of the vehicle. In this case, the second valve arrangement 6 is switched to position 3.2 or position 3.3 (see Figure 5), so that a connection A3 of the second valve arrangement 6 is connected to a connection A2. The third valve arrangement 7 is then switched to position 4.1, as shown in Figure 6, so that a connection A1 of the third valve arrangement 7 is connected to a connection A3. Thus, heat from the seventh heat exchanger WT7 can reach the first sub-circuit 11 upstream of the first pump P1 via the second and third valve arrangements 6, 7 and the connecting line 18 (see Figure 1). In this case, all pumps P1, P2, P3 and P4 are preferably active.

[0103] Furthermore, an operating method can be enabled in which the smallest possible coolant circuit is realized by switching the second valve arrangement 6 to position 3.1, so that the seventh heat exchanger WT7 is directly connected to the sixth heat exchanger WT6 via the fourth pump P4 for rapid heating of the interior 3. The second cooling circuit 20 can, in particular, reach very high temperatures, in particular 90 to 130 °C, in a very short time and thus provide heat for the interior, in particular at the beginning of a journey with the vehicle, for example, to dehumidify the interior 3 or to dehumidify or defrost the windows.

[0104] The thermal system 1 according to the invention can provide a variety of applications in an electrically powered vehicle. In particular, the cooler on the fourth heat exchanger WT4 can also be used to provide heat, so that the thermal system has two heat sources, namely the fourth heat exchanger WT4 and the seventh heat exchanger WT7. Furthermore, the battery or the power electronics, or the electric axles via the first and fifth heat exchangers WT1, WT5 (second valve arrangement 6 in position 3.2 or 3.3), can also be used as heat sources. Ambient heat from the environment 4 can also be utilized via the third heat exchanger WT3.

[0105] Furthermore, use cases can also be covered in which the

[0106] Drive battery 2 and / or the power electronics 9 / electric axles are not only cooled but also heated (second valve arrangement 6 in position 3.2 or 3.3, third valve arrangement 7 in position 4.1 or 4.2).

[0107] The three valve arrangements 5, 6, and 7 are preferably designed as proportional valves and can be controlled independently of one another. Furthermore, the four pumps P1, P2, P3, and P4 can each be controlled separately and, in particular, operated at different speeds, allowing very precise mixing temperatures in the respective partial circuits 11, 12, 13, and 14.

[0108] The thermal system 1 according to the invention can also ensure that in the event of failure of one of the three valve arrangements 5, 6, 7 or one of the four pumps P1, P2, P3, P4, there is no risk of overheating of the drive battery 2 and / or the power electronics 9 / electric axles, as the other pumps at least partially take over the coolant supply.

[0109] Figure 7 shows a second embodiment of the thermal system 1, in which the first valve arrangement 5 is constructed differently. Figure 7 shows a second embodiment in which the first valve arrangement 5 is a 5 / 5-way valve with five ports and 5 positions. The five positions are designated in Figure 5 by the reference numerals 9.1, 9.2, 9.3, 9.4 and 9.5. Below the positions, the equivalents from the first embodiment are shown with the nomenclature used there. Thus, position 9.1 corresponds to position 8.5 of the first embodiment, position 9.2 corresponds to position 8.3, position 9.3 corresponds to position 8.6, position 9.4 corresponds to position 8.7 and position 9.5 corresponds to position 8.8.

Claims

- TI - Claims 1 . Thermal system for a vehicle with an electric drive battery (2) and an interior (3) for passengers, comprising: - a first cooling circuit (10) with a first coolant, and - a second cooling circuit (20) with a second coolant, - wherein the second coolant is propane or a coolant that is hazardous to the health of the occupants and the first coolant is a different coolant than the second coolant, in particular a water-glycol mixture, - wherein the first cooling circuit (10) has a first heat exchanger WT1 on the drive battery (2), a second heat exchanger WT2 to the interior (3), a third heat exchanger WT3 to the environment (4) and a fourth heat exchanger WT4 to the second cooling circuit (20) for exchanging heat or cold, - wherein the second cooling circuit (20) is designed as an evaporator at the fourth heat exchanger WT4 in order to enable a reduction in the temperature of the first coolant at the fourth heat exchanger WT4, and - a first valve arrangement (5) which is arranged in the first cooling circuit (10) and is designed to connect the first heat exchanger WT1 to the third heat exchanger WT3 or the first heat exchanger WT1 to the fourth heat exchanger WT4, and - wherein the first valve arrangement (5) is further configured to connect the second heat exchanger WT2 to the interior (3) with the fourth heat exchanger WT4 to the second cooling circuit (20) in order to cool interior air in the interior (3) of the vehicle.

2. Thermal system according to claim 1, wherein the first valve arrangement (5) is arranged to connect the first heat exchanger WT1 simultaneously with the third heat exchanger WT3 and the fourth heat exchanger WT4 3. Thermal system according to claim 1 or 2, wherein the first valve arrangement (5) is arranged to connect or disconnect the second heat exchanger WT2 exclusively with the fourth heat exchanger WT4.

4. Thermal system according to one of the preceding claims, further comprising a first sub-circuit (11) of the first cooling circuit (10), in which the first heat exchanger WT1, the second heat exchanger WT3 and a first pump P1 are arranged to circulate the first coolant in the first sub-circuit (11).

5. Thermal system according to claim 4, further comprising a second sub-circuit (12) of the first cooling circuit (10), in which the second heat exchanger WT2, the fourth heat exchanger WT4 and a second pump P2 are arranged to circulate the first coolant in the second sub-circuit (12).

6. Thermal system according to claim 5, wherein the first valve arrangement (5) is arranged to connect the first sub-circuit (11) and the second sub-circuit (12) to one another, so that the first pump P1 generates a coolant flow through the first heat exchanger WT1 and the third heat exchanger WT3 and the second pump P2 generates a coolant flow through the second heat exchanger WT2 and the fourth heat exchanger WT4.

7. Thermal system according to claim 5 or 6, wherein a check valve (31) is arranged in the second sub-circuit (12) between the second heat exchanger WT2 and the first valve arrangement (5) in order to prevent backflow into the second heat exchanger WT2 during operation of the first pump P1.

8. Thermal system according to one of the preceding claims, wherein the first cooling circuit (10) further comprises a fifth heat exchanger WT5 of a power electronics (9), in particular including an electrical axis, a sixth heat exchanger WT6 to the interior (3) in order to heat the interior, a seventh heat exchanger WT7 to the second cooling circuit (20) in order to extract heat from the second cooling circuit (20), and an eighth heat exchanger WT8 to the environment (4).

9. Thermal system according to one of claims 5 to 8, further comprising a third sub-circuit (13) of the first cooler circuit (10) in which the fifth heat exchanger WT5, the eighth heat exchanger WT8 and a third pump P3 are arranged to circulate the first coolant in the third sub-circuit (13).

10. Thermal system according to claim 9, further comprising a fourth sub-circuit (14) of the first cooling circuit (10), in which the sixth heat exchanger WT6, the seventh heat exchanger WT7 and a fourth pump P4 are arranged to circulate the first coolant in the fourth sub-circuit (14).

11. Thermal system according to claim 10, further comprising a second valve arrangement (6) which connects or separates the third sub-circuit (13) and the fourth sub-circuit (14).

12. Thermal system according to one of claims 4 to 11, further comprising a third valve arrangement (7) which connects or separates the third partial circuit (13) and the first partial circuit (11).

13. Thermal system according to one of the preceding claims, wherein the first valve arrangement (5) is a 5 / 8-way valve or a 5 / 5-way valve or a 3 / 4-way valve or is divided into two or more sub-valve arrangements.

14. Thermal system according to one of claims 10 to 13, comprising exactly four pumps P1, P2, P3, P4, wherein one pump is arranged in each of the four partial circuits 11, 12, 13, 14.

15. Thermal system according to one of claims 9 to 14, comprising a common cooler in which the third heat exchanger WT3 and the eighth heat exchanger WT8 are arranged hydraulically separated.

16. Thermal system according to one of claims 8 to 15, - wherein heat from the seventh heat exchanger WT7 and / or heat from the fifth heat exchanger WT5 can be supplied to the sixth heat exchanger WT6 in order to heat the interior (3) of the vehicle and / or - wherein the third heat exchanger WT3 and / or the fourth heat exchanger WT4 are connectable to the second heat exchanger WT2 in order to cool the interior (3) of the vehicle and / or - wherein heat from the seventh heat exchanger WT7 can be supplied to the first heat exchanger WT1 in order to heat the electric drive battery (2).

17. Thermal system according to one of claims 8 to 16, wherein the third heat exchanger WT3 has an inlet (31) connected to the first valve arrangement (5) and an outlet (32) connected to the first pump P1, wherein the first valve arrangement (5) is arranged to connect the inlet (31) of the third heat exchanger WT3 to the second pump P2 in order to supply heat from the third heat exchanger WT3 to the fourth heat exchanger WT4.

18. Thermal system according to one of claims 5 to 17, arranged for parallel operation of the first pump P1 and the second pump P2 and / or wherein the first sub-circuit 11 is directly connected to the second sub-circuit (12) by means of a first direct connection (15).

19. Thermal system according to one of claims 5 to 18, wherein the first sub-circuit (11) is directly connected to the third sub-circuit (13) by means of a second direct connection (16).

20. A method for performing thermal management of an electric vehicle by means of a thermal system according to one of the preceding claims.

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