FUEL CELL TEMPERATURE CONTROL SYSTEM

Abstract

The present development relates to a system (5) for temperature control of a fuel cell (20) of a motor vehicle (1) comprising: - a coolant circuit (11) of a motor vehicle air conditioning system (10), which has a fluid-carrying line (15), - a fluid-carrying circuit (21) which is thermally coupled to the fuel cell (20), and - a heat exchanger (30) by means of which the coolant circuit (11) and the fluid-carrying circuit (21) for controlling the temperature of the fuel cell (20) can be thermally coupled to one another.

Description

Technical area

[0001] The present development relates to a system for tempering a fuel cell of a motor vehicle and a method for tempering a corresponding fuel cell. background

[0002] For optimal operation of a motor vehicle fuel cell, it is necessary that the fuel cell be operated within a specified temperature window. For this purpose, it is known to equip the fuel cell with a separate heater.

[0003] Furthermore, it is generally known from CN 114079062 B to thermally couple a motor vehicle heater with a heater for the fuel cell via a heat exchanger.

[0004] Motor vehicles with an air conditioning system typically have a closed coolant circuit that connects a compressor, a condenser, an expansion device, and an evaporator. During operation of the vehicle air conditioning system, thermal energy is released into the environment via the condenser. Thermal energy is absorbed from the environment in the area of the evaporator. In this way, for example, the vehicle interior can be cooled to a predetermined temperature level.

[0005] Against this background, the present development aims to optimize the temperature control of a motor vehicle's fuel cell, particularly by reducing the vehicle's energy consumption for temperature control of the fuel cell. Furthermore, the solution should be as simple to implement as possible. Advantageous designs

[0006] This object is achieved with a system for controlling the temperature of a fuel cell, with a motor vehicle, and with a method for controlling the temperature of a fuel cell according to the features of the independent patent claims. Advantageous embodiments are the subject of dependent patent claims.

[0007] In a first aspect, a system for controlling the temperature of a fuel cell of a motor vehicle is provided. This system comprises a coolant circuit of a motor vehicle air conditioning system, which has a fluid-carrying line. The system further comprises a fluid-carrying circuit that is thermally coupled to the fuel cell. The fluid-carrying circuit and the coolant circuit are fluidically isolated from one another. They are separate circuits.

[0008] Finally, the system includes a heat exchanger that thermally couples the coolant circuit and the fluid-carrying circuit for controlling the temperature of the fuel cell. In this way, excess thermal energy generated during operation of the vehicle's air conditioning system can be used for temperature control, particularly for heating the fuel cell.

[0009] In particular, it is intended to feed waste heat generated during operation of the coolant circuit of the motor vehicle air conditioning system into the fluid-carrying circuit of the fuel cell, thereby providing particularly efficient heating for the fuel cell. Any additional heating of the fuel cell may be eliminated, or the energy required for additional heating for the fuel cell may be significantly reduced, since at least part of the energy required to heat the fuel cell can be obtained or recovered from waste heat of the motor vehicle air conditioning system.

[0010] According to a further development of the system, the coolant circuit of the motor vehicle air conditioning system has at least one compressor and one condenser, which are connected to one another via the fluid-carrying line of the coolant circuit. The compressor and the condenser are connected to one another in a fluid-carrying manner. Relative to the coolant circuit and the flow direction of the coolant flowing through the coolant circuit, the condenser is located downstream of the compressor. Comparatively high temperatures typically prevail downstream of the compressor, since the coolant circulating through the coolant circuit is compressed by the compressor.

[0011] The heat exchanger is thermally coupled to a section of the coolant circuit located between the condenser and the compressor. In this way, the heat exchanger is thermally coupled to the so-called hot side of the coolant circuit, and excess thermal energy, in particular, generated downstream of the compressor, can be transferred to the fluid-carrying circuit, i.e., the heating circuit for the fuel cell.

[0012] This creates thermal synergy effects. On the one hand, the removal of excess thermal energy from the coolant circuit of the vehicle's air conditioning system can be improved. At the same time, the thermal energy released into the environment by the vehicle's air conditioning system can be used, at least in part, to heat the fuel cell.

[0013] According to a further embodiment, the heat exchanger is thermally coupled to a section located between the condenser and the expansion element of the coolant circuit of the motor vehicle air conditioning system. In this respect, the heat exchanger can also be arranged downstream of the condenser. Both the condenser of the coolant circuit and the heat exchanger serve to cool the area of the coolant circuit located downstream of the compressor, thereby dissipating thermal energy from the motor vehicle air conditioning system to the environment or to the fuel cell.

[0014] According to a further embodiment of the system, the coolant circuit has a bypass line. This bypass line is branched off from the fluid-carrying line, i.e., the primary line of the coolant circuit, via an adjustable valve. The heat exchanger is thermally coupled, particularly or exclusively, to the bypass line. The adjustable valve can be used to control or regulate the flow of coolant through the bypass line.

[0015] In this way, the amount of thermal energy flowing through the bypass line and thus also through the heat exchanger can be regulated or adjusted as needed. For example, if heating of the fuel cell is not required under certain operating conditions, the bypass line can be fluidically decoupled from the coolant circuit of the vehicle's air conditioning system. However, if maximum heating power is required for the fuel cell, the valve can be fully opened, allowing all of the coolant flowing through the fluid-carrying circuit to flow through the bypass line.

[0016] The valve can be designed, for example, as a three-way valve. The valve can be arranged, in particular, downstream of the compressor and upstream of the condenser. The entire bypass line can be located between the compressor and the condenser, or a downstream section of the bypass line can flow back into the fluid-carrying line of the coolant circuit upstream of the condenser.

[0017] According to a further embodiment, the bypass line is connected in a fluidically parallel manner to a section of the fluid-carrying line located downstream of the compressor and upstream of an expansion valve of the coolant circuit. The bypass line can, in particular, be connected in parallel to the fluid-carrying line of the coolant circuit. It can be connected in parallel to a section of the fluid-carrying line located downstream of the compressor and upstream of the condenser.

[0018] However, the bypass line can also be connected in parallel to a section of the fluid-carrying line of the coolant circuit, which is located downstream of the condenser and upstream of the expansion element. In both configurations, heat is dissipated from the coolant circuit toward the fluid-carrying circuit, which is thermally coupled to the fuel cell.

[0019] According to a further embodiment, the system comprises an electronic controller for regulating or adjusting the valve. The system further comprises a first temperature sensor, which is thermally coupled to the coolant circuit. It further comprises a second temperature sensor, which is thermally coupled to the fluid-carrying circuit. The controller is data-linked to both the first temperature sensor and the second temperature sensor. The controller is further configured to regulate the valve depending on signals from the first temperature sensor and depending on signals from the second temperature sensor.

[0020] Using the two temperature sensors, the respective temperatures of the coolant circuit and the fluid-carrying circuit can be monitored and measured. If the temperature measurement reveals a difference that could be used, for example, to heat the fuel cell, the controller can be configured to open the valve to divert a portion of the heated coolant flowing through the coolant circuit into the bypass line, thus transferring thermal energy to the fuel cell's fluid-carrying circuit via the heat exchanger.

[0021] In other operating conditions, for example when the fuel cell is to be heated or warmed and if the temperature in the area of the coolant circuit downstream of the compressor is not sufficiently high for heating or for heating the fuel cell, the valve can be closed in order to prevent unwanted cooling of the fuel cell.

[0022] According to a further embodiment, the control system is designed in particular to use waste heat from the motor vehicle air conditioning system to heat or warm up the fuel cell by regulating the valve. In this way, both thermal circuits, i.e. the coolant circuit of the motor vehicle air conditioning system and the fluid-carrying circuit, which is thermally coupled to the fuel cell, can be operated in a thermally optimized manner. Due to the thermal coupling by means of the heat exchanger, thermal energy or waste heat released by the coolant circuit can be used particularly elegantly and efficiently to heat or warm the fuel cell. The total energy consumption of the motor vehicle, which must be used, for example, to heat the fuel cell, can be reduced in this way.

[0023] According to a further embodiment of the system, the fluid-carrying circuit comprises a fluid-carrying line thermally coupled to the heat exchanger and a pump for circulating a heat exchange medium through the fluid-carrying circuit. The fluid-carrying circuit can, in particular, be provided with a fluid, such as water, which enables heat exchange with the heat exchanger and with the fuel cell.

[0024] According to a further embodiment, the fluid-carrying circuit can also be provided with an additional heater in order to set or achieve a desired temperature in the area of the fuel cell independently of the thermal coupling and / or independently of the respective operating state of the motor vehicle air conditioning system.

[0025] According to a further aspect of the present development, a motor vehicle, such as a passenger car or a small van, is also provided, which has a motor vehicle air conditioning system and a fuel cell, as well as a previously described system for temperature control of the fuel cell. Since the motor vehicle comprises a previously described system for temperature control of a fuel cell of a motor vehicle, all features, advantages, and possible applications previously described with regard to the system also apply equally to the motor vehicle; and vice versa.

[0026] Finally, according to a further aspect, a method for controlling the temperature, for example for heating or warming up a fuel cell of a motor vehicle, is provided using a previously described system. Thermal energy is transferred from a motor vehicle air conditioning system to the fuel cell by means of the system's heat exchanger. In this way, the motor vehicle air conditioning system can be heated or warmed up to a predetermined temperature level, for example, to ensure smooth or optimal operation of the fuel cell.

[0027] The method particularly encompasses the operation of the previously described system or motor vehicle. In this respect, all features, advantages, and possible applications described above with regard to the system and motor vehicle also apply equally to the method for controlling the temperature of the fuel cell, and vice versa.

[0028] According to a further embodiment of the method, the fuel cell is heated or warmed using waste heat from the vehicle's air conditioning system. The waste heat from the vehicle's air conditioning system can be used partially or entirely to heat or warm the fuel cell. In any case, a portion of the waste heat generated in the coolant circuit of the vehicle's air conditioning system can be transferred to the fuel cell using the heat exchanger and the system provided here.

[0029] Additional heating power for heating the fuel cell, for example, using an auxiliary heater, can be reduced in this way. The vehicle's energy consumption, for example, for operating the vehicle's air conditioning system or for controlling the temperature of the fuel cell, can be minimized or optimized in this way. Short description of the characters

[0030] Further objectives, features, and advantageous embodiments of the present development are explained in the following description of an exemplary embodiment. Herein: Fig. 1 is a schematic side view of a motor vehicle, and Fig. 2 Block diagram of the system for temperature control of the vehicle's fuel cell. Detailed description

[0031] The Fig. The motor vehicle 1 schematically illustrated in Figure 1 comprises a motor vehicle body 2 and an interior 3 functioning as a passenger compartment. The motor vehicle 1 further comprises a motor vehicle air conditioning system 10 and a fuel cell 20. The fuel cell serves to generate electrical energy, which can be used to operate the motor vehicle 1, for example, to drive the motor vehicle 1.

[0032] To operate the fuel cell 20, it is necessary to heat it to a predetermined temperature level or to maintain the temperature in the area of the fuel cell 20 within a predetermined temperature range. For this purpose, a system 5 for temperature control of a fuel cell 20 is provided, which is shown as a block diagram in Fig. 2 is shown.

[0033] The system 5 comprises a coolant circuit 11 of the motor vehicle air conditioning system 10. The coolant circuit has, in particular, a fluid-carrying line 15, for example, for a refrigerant. The motor vehicle air conditioning system 10 further comprises a compressor 12, a condenser 18, an expansion element 16, and an evaporator 14. The compressor 12 compresses the coolant circulating through the coolant circuit 11. In the region of the condenser 18, the coolant heated by compression can release thermal energy to the environment. The expansion element 16 reduces the pressure in the coolant circuit 11, thereby cooling the coolant, so that the evaporator downstream of the expansion element 16 can absorb thermal energy from the environment or cool the environment.

[0034] The system 5 further comprises a fluid-carrying circuit 21, which is thermally coupled to the fuel cell 20. The fluid-carrying circuit 21 also has a fluid-carrying line 25. The fluid-carrying circuit 21 further comprises a pump 22, by means of which a heat medium can be pumped through the fluid-carrying circuit 21.

[0035] The coolant circuit 11 of the motor vehicle air conditioning system 10 and the fluid-carrying circuit 21 can be thermally coupled to one another by means of a heat exchanger 30. The heat exchanger 30 can be thermally coupled, in particular, to a so-called hot side of the coolant circuit 11. The hot side extends downstream of the compressor 12 and upstream of the expansion element 16. In the exemplary embodiment shown here, the heat exchanger 30 is thermally coupled to a section 9 of the coolant circuit 11, which is located downstream of the compressor 12 and upstream of the condenser 18.

[0036] Furthermore, a bypass line 13 is provided in that section 9, which can be variably supplied with the coolant or refrigerant of the coolant circuit 11 via a valve 19. The valve 19 can be designed as a control valve or a regulating valve. In particular, it can be electronically controlled by a controller 40. By means of the valve 19, the flow of the heated refrigerant through the bypass line 13 can be regulated as needed, thus regulating the heat supply to the heat exchanger 30.

[0037] The bypass line 13 branches off downstream of the valve 19 toward the heat exchanger 30. It enters the heat exchanger 30 via a first inlet 33 of the heat exchanger. The bypass line 13 is connected again to the fluid-carrying line 15 of the coolant circuit 11 via a first outlet 34 of the heat exchanger 34. The heat exchanger 30 further comprises a further, approximately a second inlet 31, which is fluid-carryingly connected to the line 25.

[0038] The heat exchanger 30 further comprises a further, for example, second outlet 32, which is fluidically connected to the inlet 31 and which also opens into the line 25. The heat exchanger 30 is fluidically connected in parallel with the coolant circuit 11, and in particular via the bypass line 13 to the coolant circuit. The heat exchanger 30 is connected in series in the fluid-conducting circuit 21 for the fuel cell 20.

[0039] The controller 40 is further connected for data purposes to a first temperature sensor 41 and a second temperature sensor 42. The first temperature sensor 41 can be used to determine a temperature of the coolant circuit 11 downstream of the compressor 12. The second temperature sensor 42 can be used to measure or determine a temperature in the region of the fluid-carrying circuit 21. By comparing the temperatures in the region of the coolant circuit 11 and the fluid-carrying circuit 21, or by appropriate data processing, the valve 19 can be controlled as needed in order to regulate and control heat transfer from the coolant circuit 11 of the motor vehicle air conditioning system 10 to the fluid-carrying circuit 21 of the fuel cell 20.

[0040] This can, in particular, increase the efficiency of heating the fuel cell 20. Waste heat generated, particularly in the area of the air conditioning system 10 or in the area of the coolant circuit 11, can be used to heat or warm up the fuel cell 20. In this way, both the air conditioning system 10 and the heating system for the fuel cell 20 can be operated far more efficiently than without the thermal coupling achieved by means of the heat exchanger 30.

[0041] The illustrated embodiments merely show possible configurations of the development, for which numerous further variants are conceivable within the scope of the development. The exemplary embodiments shown are in no way to be interpreted as limiting the scope, applicability, or configuration options of the development. This description merely shows the person skilled in the art one or several possible implementations of an exemplary embodiment. Thus, a wide variety of modifications can be made to the function and arrangement of the described elements without departing from the scope of protection defined by the following claims or their equivalents. List of reference symbols 1 motor vehicle 2 Motor vehicle body 3 Interior 5 Systems Section 9 10 Automotive air conditioning system 11 Coolant circuit 12 Compressor 13 Bypass line 14 evaporators 15 Line 16 Expansion organ 18 Capacitor 19 Valve 20 fuel cells 21 fluid-carrying circuit 22 Pump 25 Line 30 heat exchangers 31 Entrance 32 Outlet 33 Entrance 34 Outlet 40 Control 41 Sensor 42 Sensor QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] CN 114079062 B

[0003]

Claims

[1] System (5) for temperature control of a fuel cell (20) of a motor vehicle (1) comprising: - a coolant circuit (11) of a motor vehicle air conditioning system (10), which has a fluid-carrying line (15), - a fluid-carrying circuit (21) which is thermally coupled to the fuel cell (20), and - a heat exchanger (30) by means of which the coolant circuit (11) and the fluid-carrying circuit (21) for controlling the temperature of the fuel cell (20) can be thermally coupled to one another. [2] System (5) according to claim 1, wherein the coolant circuit (11) comprises at least one compressor (12) and one condenser (18) which are connected to one another via the fluid-carrying line (15), and wherein the heat exchanger (30) is thermally coupled to a section (9) of the coolant circuit (11) located between the condenser (18) and the compressor (12). [3] System (5) according to one of the preceding claims, wherein the coolant circuit (11) has a bypass line (13) branching off from the fluid-carrying line (15) via a controllable valve (19), and wherein the heat exchanger (30) is thermally coupled to the bypass line (13). [4] System (5) according to claim 2 and 3, wherein the bypass line (13) is connected fluidically parallel to a section of the fluid-carrying line (15) which is located downstream of the compressor (12) and upstream of an expansion valve (16) of the coolant circuit (11). [5] System (5) according to claim 3 or 4, further comprising an electronic controller (40) for regulating the valve (19), wherein the controller (40) is data-linked to a first temperature sensor (41) of the coolant circuit (11) and to a second temperature sensor (42) of the fluid-carrying circuit (21) and is designed to regulate the valve (19) in dependence on signals from the first temperature sensor (41) and signals from the second temperature sensor (42). [6] System (5) according to claim 5, wherein the controller (40) is designed to use waste heat from the motor vehicle air conditioning system (10) to heat or warm up the fuel cell (20) by regulating the valve (19). [7] System (5) according to one of the preceding claims, wherein the fluid-carrying circuit (21) comprises a fluid-carrying line (25) thermally coupled to the heat exchanger (30) and a pump (22) for circulating a heat exchange medium through the fluid-carrying circuit (21). [8] Motor vehicle (1) with a motor vehicle air conditioning system (10) and with a fuel cell (20) and with a system (5) according to one of the preceding claims. [9] Method for tempering a fuel cell (20) of a motor vehicle (1) using a system (5) according to one of the preceding claims 1 to 6, wherein thermal energy is transferred from a motor vehicle air conditioning system (10) to the fuel cell (20) by means of the heat exchanger (30). [10] Method according to claim 9, wherein the fuel cell (20) is heated by means of waste heat from the motor vehicle air conditioning system (10).

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