Thermal management system for a battery of a motor vehicle and motor vehicle with a thermal management system

Abstract

Thermal management system (100) for a battery (10) of a motor vehicle, in particular a battery-electric vehicle, comprising a coolant circuit (11), wherein a battery (10), a refrigeration machine (12), an auxiliary heating device (13) and a fluid control device (14, 14a, 14b) are arranged in the coolant circuit (11), characterized in that the fluid control device (14, 14a, 14b) is designed to distribute a volume flow of a coolant emerging from the auxiliary heating device (13) to the refrigeration machine (12) and / or the battery (10) as required, and in that the coolant circuit (11) has a branch (15) into a first coolant branch (16) and a second coolant branch (17) downstream of the auxiliary heating device (13) in the flow direction of the coolant, wherein the refrigeration machine (12) is arranged in the first coolant branch (16), wherein the first coolant line (16) and the second coolant line (17) are connected to the fluid control device (14, 14a, 14b) and are combined into a third coolant line (18) by means of the fluid control device (14, 14a, 14b), wherein the auxiliary heating device (13) is arranged in the third coolant line (18), and by by means of the fluid control device (14) the first coolant line (16) can be separated from the third coolant line (18) and the second coolant line (17) can be connected to the third coolant line (18), so that the coolant heated by the auxiliary heating device (13) can flow directly into the battery (10) without passing through the refrigeration machine (12).

Description

[0001] The present invention relates to a thermal management system for a battery of a motor vehicle, in particular a battery-electric vehicle, comprising a coolant circuit, wherein a battery, a refrigeration machine, an auxiliary heating device and a fluid control device are arranged in the coolant circuit.

[0002] Furthermore, the present invention relates to a motor vehicle with a thermal management system.

[0003] Thermal management systems are used to cool or heat the battery of a motor vehicle, especially the battery of a battery-electric vehicle. The battery is primarily the energy storage device for operating the drive motors. Especially in battery-electric vehicles, the requirements for the thermal management system are diverse and complex. Such thermal management systems are often thermally connected to other cooling or refrigerant circuits, for example, to a refrigerant circuit for controlling the temperature in a vehicle interior.

[0004] In known thermal management systems, the use of auxiliary heating devices, in particular PTC auxiliary heaters, is known. In the prior art, these auxiliary heating devices are arranged on the sink side or hot side of a heat pump and thus in the cooling or refrigerant circuit for controlling the temperature of the vehicle interior. A disadvantage of arranging an auxiliary heating device on the hot side, for example in a cooling or refrigerant circuit for controlling the temperature of a vehicle interior, is that sharing the auxiliary heating device for the battery and the vehicle interior results in losses, since a higher temperature level prevails in the components and the cooling or refrigerant lines.

[0005] A thermal management system for a purely electric vehicle is known from CN 1 11 516 556 A. The system comprises a heating system, a high-voltage system, a high-voltage system cooling system, and a battery cooling system. A four-way valve is arranged between the high-voltage system cooling system and the heating system to connect the two circuits. A high-voltage electric heater can be used entirely to heat the passenger compartment and the battery.

[0006] CN 1 09 572 365 A discloses a thermal management system of a hybrid electric vehicle. According to the thermal management system of the hybrid electric vehicle, an engine cooling system, a charge air cooling system, a heating system, a power system cooling system, a battery cooling system, and an air conditioning system are integrated into a more efficient system using two four-way valves.

[0007] CN 1 10 481 271 A discloses a thermal management system for all-electric vehicles, comprising a heating loop, a power system cooling loop, and a battery cooling loop. A three-way valve is arranged between the power system cooling loop and the battery cooling loop to connect the two circuits.

[0008] CN 1 10 949 182 A discloses an electric vehicle thermal management system with a battery control loop and a power system control loop. The battery control loop is coupled to a battery pack of the electric vehicle. The power system control loop comprises a main path, a first branch path, and a second branch path, wherein heat transfer fluid in the power system control loop can flow from the main path into the first branch path and the second branch path and finally flow back to the main path. A radiator is arranged in the main path.

[0009] CN 1 12 109 521 A discloses a vehicle thermal management system for a purely electric vehicle. The thermal management system comprises a refrigerant circuit, a warm air-water system circuit, a battery-water system circuit, an engine-water system circuit, a water-cooled condenser for coupling the refrigerant circuit to the warm air-water system circuit, a chiller for coupling the refrigerant circuit to the battery-water system circuit, and a four-way valve for coupling the battery-water system circuit to the engine-water system circuit.

[0010] DE 10 2019 100 096 A1 discloses an air conditioning and battery cooling arrangement with an A / C coolant circuit and an electric drive train coolant circuit as well as a refrigerant circuit, wherein the A / C coolant circuit and the electric drive train coolant circuit are coupled to one another via a 4 / 2-way coolant valve in such a way that the A / C coolant circuit and the electric drive train coolant circuit are designed to be separately operable or to be flowed through in series, and the A / C coolant circuit has at least one A / C coolant radiator for dissipating heat to the ambient air, a coolant pump and a condenser via which the A / C coolant circuit is thermally connected to the refrigerant circuit, and the electric drive train coolant circuit has at least one battery cooler, a coolant pump, a drive train coolant radiator for dissipating heat to the ambient air and a chiller. has,via which the electric drive train coolant circuit is thermally connected to the refrigerant circuit, and the refrigerant circuit has at least one compressor, the condenser, an ambient heat exchanger for heat dissipation to the ambient air or heat absorption from the ambient air, an expansion device and the chiller.

[0011] DE 10 2013 008 800 A1 discloses a vehicle coolant system comprising at least two independently operable coolant circuits, wherein at least one first coolant circuit operates at a first temperature level and at least one second coolant circuit operates at a second temperature level that is lower than the first temperature level. The first coolant circuit is provided, in particular, for controlling the temperature of an internal combustion engine or an electric machine, and the second cooling circuit is provided for controlling the temperature of an energy storage device. A recuperation device is provided for thermally coupling the at least one first and the at least one second coolant circuit.

[0012] WO 2020 / 080 991 A1 discloses a cooling system for controlling the temperature of a battery within a specific temperature range, the cooling system consisting of a refrigeration machine and a cooling line arranged in heat exchange with the refrigeration machine, a heat source and a high-temperature line arranged in heat exchange with the heat source;a battery line arranged in heat exchange with the battery, at least one pump arranged to pump a cooling liquid in at least one of said lines during operation, and a condenser and a refrigeration circuit arranged in heat exchange with the condenser, wherein a working medium is arranged to be circulated in this refrigeration circuit during operation, wherein a valve is arranged to selectively bring the cooling line into heat exchange with the battery line to ensure cooling of the battery, and wherein a valve is arranged to selectively bring the high-temperature line into heat exchange with the battery line to heat the battery;

[0013] The present invention is based on the object of providing a thermal management system for a motor vehicle, in particular for a battery-electric vehicle, which has a significant reduction in complexity and efficiency advantages compared to known thermal management systems.

[0014] To achieve the object underlying the invention, a thermal management system for a battery of a motor vehicle, in particular a battery-electric vehicle, comprising a coolant circuit, wherein a battery, a refrigeration machine, an auxiliary heating device and a fluid control device are arranged in the coolant circuit, is proposed, wherein it is further provided that the fluid control device is designed to distribute a volume flow of a coolant emerging from the auxiliary heating device to the refrigeration machine and / or the battery as required.

[0015] The battery can be the primary energy source for operating the drive motors of a battery-electric vehicle. The refrigeration unit, also known as a chiller, preferably provides the thermal connection to an additional cooling or refrigerant circuit required to maintain the temperature of the vehicle interior.

[0016] The fluid control device is designed to distribute a volume flow of the coolant between the refrigeration machine and the battery. This means, in particular, that 100% of the volume flow can be supplied to either the refrigeration machine or the battery using the fluid control device. Furthermore, the volume flow of the coolant can also be distributed proportionally between the battery and the refrigeration machine using the fluid control device.

[0017] According to the invention, the auxiliary heating device is arranged in the coolant circuit of the thermal management system. In contrast to the prior art, in which the auxiliary heating device is located on the sink side or hot side of the refrigeration machine used to regulate the temperature of the passenger compartment, in the present invention the auxiliary heating device is arranged on the source side or cold side of the refrigeration machine. The auxiliary heating device can therefore be used both for temperature control of the battery and, via the refrigeration machine, for temperature control of the vehicle interior. This is made possible in particular by the fact that the volume flow of the coolant can be distributed between the refrigeration machine and / or the battery as required by means of the fluid control device.

[0018] It is advantageously provided that the cooling machine is a chiller and / or that the auxiliary heating device is an electrical auxiliary heating device, preferably a high-voltage heater, more preferably a PTC auxiliary heater.

[0019] It can be further advantageously provided that the fluid control device is a valve, in particular a three-way valve or a four-way valve.

[0020] According to the invention, the coolant circuit has a branching into a first coolant line and a second coolant line downstream of the auxiliary heating device in the flow direction of the coolant, wherein the refrigeration machine is arranged in the first coolant line.

[0021] Furthermore, the invention provides that the first coolant line and the second coolant line are connected to the fluid control device and are combined into a third coolant line by means of the fluid control device, wherein the auxiliary heating device is arranged in the third coolant line.

[0022] In other words, a coolant flows through the auxiliary heating device in the direction of flow and then splits into a first coolant line and a second coolant line through the branch. The first coolant line and the second coolant line are then combined by the fluid control device to form the third coolant line, in which the auxiliary heating device is located. The third coolant line runs from the fluid control device to the branch.

[0023] It is preferably provided that a switching device, in particular a switching valve, is provided in the third coolant line, wherein the switching device is designed to direct a volume flow of the coolant into a fourth coolant line, wherein the fourth coolant line is fluidically connected to the first coolant line between the refrigeration machine and the fluid control device.

[0024] With even further advantage, it can be provided that a pump is arranged in the third coolant line.

[0025] Furthermore, it is preferably provided that the battery is arranged in the third coolant line.

[0026] The battery is therefore preferably located in the coolant line in which the auxiliary heating device is also located. The battery can be arranged upstream of the auxiliary heating device in the direction of flow, and more preferably upstream of the switching device, in the third coolant line. In this embodiment, the volume flow of the coolant can be distributed by the fluid control device in such a way that the battery can be heated and cooled. If, for example, the first coolant line and the third coolant line are fluidically connected to one another by means of the fluid control device and the second coolant line is fluidically separated from the third coolant line, then by operating the auxiliary heating device, a heated coolant emerging from the auxiliary heating device can be supplied to the battery through the branch and the refrigeration machine via the fluid control device.When the refrigeration unit is not in operation, this allows the battery to be heated or warmed. Furthermore, the auxiliary heating device can be used in the same way to raise the refrigeration unit to a higher temperature level, allowing heat to be transferred more efficiently from the thermal management system via the refrigeration unit into another cooling or refrigerant circuit to control the temperature of the passenger compartment. The passenger compartment can therefore be heated using the auxiliary heating device in the coolant circuit of the thermal management system. If the auxiliary heating device is not in operation with the fluid control device in the same position, the battery can be cooled by operating the refrigeration unit.If, however, the second coolant line and the third coolant line are fluidically connected by means of the fluid control device and the third coolant line is fluidically separated from the first coolant line, a coolant heated by the auxiliary heating device can be supplied directly to the battery via the branch and the second coolant line and the battery can thus be heated.

[0027] It is preferably provided that the third coolant line has a bypass to the battery, wherein the bypass is fluidically connected to the fluid control device, wherein the fluid control device is designed to divide a volume flow of the coolant between the battery and the bypass as required.

[0028] The bypass allows coolant heated by the auxiliary heater to bypass the battery. This is particularly advantageous when the auxiliary heater is used to regulate the temperature of the refrigeration unit, but the battery does not require heating.

[0029] It can be further advantageously provided that the battery is arranged in the second coolant line, wherein the second coolant line preferably has a fifth coolant line, wherein the fifth coolant line is arranged in a parallel circuit to the battery, wherein the fifth coolant line has a pump and a check valve.

[0030] By arranging the battery in the second coolant line, the coolant heated by the auxiliary heating device can be distributed between the refrigeration machine and the battery as needed by positioning the fluid control device. Furthermore, the battery can also be cooled by the refrigeration machine. This is achieved by diverting a volume flow of coolant into the fourth coolant line and supplying it to the refrigeration machine using the switching device arranged in the third coolant line. The coolant cooled by the refrigeration machine then flows in the opposite direction to the flow direction in the first coolant line when the refrigeration machine is heating and via the branch into the second coolant line to cool the battery there.

[0031] The fifth coolant line is connected in parallel to the battery. The pump and check valve in the fifth coolant line allow a small coolant circuit to be provided through the battery and the fifth coolant line. This is particularly advantageous when the battery has neither a cooling nor a heating requirement. By operating the small coolant circuit with the fifth coolant line, temperature balancing for the battery can be achieved, i.e., a reduction in the temperature gradient within the battery. In this case, the first coolant line and the third coolant line can be fluidically connected using the fluid control device, and the second coolant line with the battery can be separated from the third coolant line. The auxiliary heating device then serves exclusively to control the temperature of the refrigeration machine on the source side.

[0032] With even further advantage, it can be provided that the coolant circuit is fluidically connected to a second coolant circuit, wherein the second coolant circuit is designed to cool traction components of a motor vehicle.

[0033] For example, the second coolant circuit may include an electric motor, power electronics, and / or a low-temperature cooler. Furthermore, the second coolant circuit may include a pump and a second switching valve. Such coolant circuits are known in the art and can be connected to the proposed thermal management system in a manner known to those skilled in the art.

[0034] Preferably, the fourth coolant line contains a branch, via which coolant from the coolant circuit of the thermal management system can be supplied to the second coolant circuit. Furthermore, it is preferably provided that a further branch is provided in the first coolant line upstream of the refrigeration machine in the flow direction, via which a coolant from the second coolant circuit can be supplied to the coolant circuit of the thermal management system. A switching valve or a further fluid control device can be provided in the second coolant circuit to control the inflow and outflow from the second coolant circuit to the coolant circuit of the thermal management system.

[0035] A further solution to the problem underlying the invention consists in providing a motor vehicle with a thermal management system as described above.

[0036] The invention is explained in more detail below with reference to the attached figures.

[0037] They show: Fig. 1 a first embodiment of a thermal management system, Fig. 2 a second embodiment of a thermal management system, and Fig. 3 a third embodiment of a thermal management system.

[0038] In the figures, identical or corresponding elements are identified by the same reference numerals.

[0039] Fig. 1 shows a thermal management system 100 for a battery 10 of a battery-electric vehicle (not shown in detail). The thermal management system 100 comprises a coolant circuit 11, wherein a battery 10, a refrigeration machine 12, also called a chiller, an auxiliary heating device 13, and a fluid control device 14 are arranged in the coolant circuit 11. The fluid control device 14 is designed as a three-way valve 14a. A branch 15 is provided downstream of the auxiliary heating device 13 in the flow direction, which branch divides the volume flow of a coolant into a first coolant line 16 and a second coolant line 17. The refrigeration machine 12 is arranged in the first coolant line 16. The first coolant line 16 and the second coolant line 17 are combined via the fluid control device 14 into a third coolant line 18, wherein the battery 10 and the auxiliary heating device 13 are arranged in the third coolant line 18.By means of the fluid control device 14, the volume flow of the coolant in the coolant circuit 11 can be divided between the first coolant line 16 and the second coolant line 17. Furthermore, a switching device 19, in particular a switching valve 19a, is arranged in the third coolant line 18, which can supply a volume flow from the third coolant line 18 to a fourth coolant line 20. The fourth coolant line 20 is connected to the first coolant line 16 via a further branch 21 downstream of the refrigeration machine 12 in the flow direction. The fourth coolant line 20 also contains a further branch 22, via which the thermal management system 100 or its coolant circuit 11 is fluidically connected to a second coolant circuit 23 known per se.Furthermore, in the first coolant line 16, between the branch 15 and the refrigeration machine 12, there is a further branch 24, via which the second coolant circuit 23 is coupled to the first coolant circuit 11. The second coolant circuit 23 can be designed in a manner known to those skilled in the art. In the case shown, the second coolant circuit 23 comprises an electric motor 25, power electronics 26, and a low-temperature cooler 27. A pump 28 and a switching valve 29 are also arranged in the second coolant circuit 23. By means of the switching valve 29, a coolant exchange between the first coolant circuit 11 and the second coolant circuit 23 can be adjusted. A pump 30 is also arranged in the coolant circuit 11 of the thermal management system 100. The thermal management system 100 can both heat and cool the battery 10.In addition, the refrigeration machine 12 can be raised to a higher temperature level by means of the auxiliary heating device 13. The refrigeration machine 12 is preferably connected with its sink or hot side to a cooling or refrigerant circuit (not shown) for controlling the temperature of a passenger compartment.

[0040] If the first coolant line 16 and the third coolant line 18 are connected by means of the fluid control device 14 and the second coolant line 17 is separated from the third coolant line 18, the refrigeration machine 12 can be raised to a higher temperature level and the battery 10 can be heated by operating the auxiliary heating device 13. If the auxiliary heating device 13 is not operated, the battery 10 can be cooled by operating the refrigeration machine 12 using the coolant conducted through the first coolant line 16 and the third coolant line 18. If only heating of the battery 10 is required, the first coolant line 16 can be separated from the third coolant line 18 by means of the fluid control device 14 and the second coolant line 17 can be connected to the third coolant line 18.In this case, the coolant heated by the auxiliary heating device 13 flows directly into the battery 10 without passing through the refrigeration machine 12 and can be used to heat the battery 10.

[0041] In Fig. 2 is a variant of the thermal management system 100 according to Fig. 1. Compared to the thermal management system 100 of the Fig. 1, a bypass 31 is also provided, which is connected to a fluid control device 14 designed as a four-way valve 14b. By means of the bypass 31, a volume flow of the coolant can be bypassed past the battery 10. This is particularly advantageous when the auxiliary heating device 13 is used exclusively to increase the temperature level of the refrigeration machine 12. To prevent the battery 10 from heating up, the heated coolant flowing from the auxiliary heating device 13 through the branch 15 into the first coolant line 16 and through the refrigeration machine 12 can be bypassed past the battery 10 by means of the bypass 31.

[0042] Fig. 3 shows another variant of the thermal management system 100. In the variant according to Fig. 3, the battery 10 is arranged in the second coolant line 17. A fifth coolant line 32 is provided parallel to the battery 10, wherein a further pump 33 and a check valve 34 are located in the fifth coolant line 32. The fluid control device 14 is as in the variant according to Fig. 1 is designed as a three-way valve 14a. By operating the auxiliary heating device 13 and correspondingly positioning the fluid control device 14, the coolant heated by the auxiliary heating device 13 can be supplied both to the refrigeration machine 12 to raise its temperature level and to the battery 10. The thermal management system 100 according to Fig.3 can also be operated in a cooling mode for the battery 10. In this case, the second coolant line 17 is connected to the third coolant line 18 by means of the fluid control device 14. Furthermore, a volume flow of the coolant from the third coolant line 18 is directed into the fourth coolant line 20 by means of the switching device 19. The coolant flowing through the fourth coolant line 20 is directed via the branch 21 into the refrigeration machine 12 and from there into the battery 10. If the third coolant line 18 is fluidically connected to the first coolant line 16 and fluidically separated from the second coolant line 17 by means of the fluid control device 14, the auxiliary heating device 13 is used exclusively to raise the refrigeration machine 12 to a higher temperature level. This case is useful when the battery 10 has neither a cooling nor a heating requirement.In this case, it may further be provided that the fifth coolant line 32 is operated by operating the pump 33, so that a coolant flows in a circuit through the battery 10 and the fifth coolant line 32. This can reduce a temperature gradient within the battery 10. List of reference symbols 100 thermal management system 10 Battery 11 Coolant circuit 12 Refrigeration machine 13 Auxiliary heating device 14 Fluid control device 14a Three-way valve 14b Four-way valve 15 Branching 16 First coolant line 17 Second coolant line 18 Third coolant line 19 Switching device 19a Switching valve 20 Fourth coolant line 21 Branching 22 Branching 23 Second coolant circuit 24 branching 25 electric motor 26 Power electronics 27 low-temperature coolers 28 Pump 29 Switching valve 30 pump 31 Bypass 32 Fifth coolant line 33 Pump 34 Check valve

Claims

[1] Thermal management system (100) for a battery (10) of a motor vehicle, in particular a battery-electric vehicle, comprising a coolant circuit (11), wherein a battery (10), a refrigeration machine (12), an auxiliary heating device (13) and a fluid control device (14, 14a, 14b) are arranged in the coolant circuit (11), characterized by that the fluid control device (14, 14a, 14b) is designed to distribute a volume flow of a coolant emerging from the auxiliary heating device (13) to the refrigeration machine (12) and / or the battery (10) as required, and in that the coolant circuit (11) has a branch (15) into a first coolant branch (16) and a second coolant branch (17) downstream of the auxiliary heating device (13) in the flow direction of the coolant, wherein the refrigeration machine (12) is arranged in the first coolant branch (16), wherein the first coolant line (16) and the second coolant line (17) are connected to the fluid control device (14, 14a, 14b) and are combined into a third coolant line (18) by means of the fluid control device (14, 14a, 14b), wherein the auxiliary heating device (13) is arranged in the third coolant line (18), and by by means of the fluid control device (14) the first coolant line (16) can be separated from the third coolant line (18) and the second coolant line (17) can be connected to the third coolant line (18), so that the coolant heated by the auxiliary heating device (13) can flow directly into the battery (10) without passing through the refrigeration machine (12). [2] Thermal management system (100) according to claim 1, characterized bythat the refrigeration machine (12) is a chiller, and / or that the auxiliary heating device (13) is an electrical auxiliary heating device (13), preferably a high-voltage heater, more preferably a PTC auxiliary heater, and / or that the fluid control device (14, 14a, 14b) is a valve, in particular a three-way valve (14a) or a four-way valve (14b). [3] Thermal management system (100) according to claim 1, characterized by in that a switching device (19, 19a), in particular a switching valve (19a), is provided in the third coolant line (18), wherein the switching device (19, 19a) is designed to guide a volume flow of the coolant into a fourth coolant line (20), wherein the fourth coolant line (20) is fluidically connected to the first coolant line (16) between the refrigeration machine (12) and the fluid control device (14, 14a, 14b). [4] Thermal management system (100) according to one of claims 1 to 3, characterized bythat a pump (30) is arranged in the third coolant line (18), and / or that the battery (10) is arranged in the third coolant line (18). [5] Thermal management system (100) according to one of claims 1 to 4, characterized by in that the third coolant line (18) has a bypass (31) to the battery (10), wherein the bypass (31) is fluidically connected to the fluid control device (14, 14b), wherein the fluid control device (14, 14b) is designed to divide a volume flow of the coolant between the battery (10) and the bypass (31) as required. [6] Thermal management system (100) according to one of claims 1 to 3, characterized bythat the battery (10) is arranged in the second coolant line (17), wherein preferably the second coolant line (17) has a fifth coolant line (32), wherein the fifth coolant line (32) is arranged in a parallel circuit to the battery (10), wherein the fifth coolant line (32) has a pump (33) and a check valve (34). [7] Thermal management system (100) according to one of the preceding claims, characterized by that the coolant circuit (11) is fluidly connected to a second coolant circuit (23), wherein the second coolant circuit (23) is designed to cool traction components of a motor vehicle. [8] Motor vehicle with a thermal management system (100) according to one of the preceding claims.

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