Cooling system for apparatus having fuel cell device and electrical energy storage device, and method for cooling fuel cell vehicle

Abstract

A vehicle cooling system for a fuel cell and an electrical energy storage device includes a first cooling circuit configured to cool the fuel cell and a second cooling circuit configured to cool the electrical energy storage device, wherein the first cooling circuit and the second cooling circuit are selectively fluidly connected to each other in response to temperatures of the fuel cell and the electrical energy storage device. The first cooling circuit may include a coolant removal point disposed downstream of the fuel cell and upstream of the heat exchanger. The first cooling circuit may also include a coolant recirculation point disposed downstream of the heat exchanger and upstream of the fuel cell.

Description

Technical Field

[0001] The present disclosure relates to a cooling system for an apparatus having a fuel cell arrangement and an electrical energy storage device, a motor vehicle and a method for cooling a fuel cell arrangement. Background Art

[0002] Optimizing the cooling system performance of fuel cell devices for vehicles with fuel cell drives represents a major challenge in the development of these vehicles. Compared to vehicles with internal combustion engines, the necessary heat dissipation capacity of the cooling system is higher. In addition, the necessary temperature level of the coolant for cooling the fuel cells or fuel cell stacks is lower, which is accompanied by a lower efficiency of the heat exchangers, which are usually arranged in the front area of ​​the vehicle.

[0003] Under certain conditions, such as uphill travel at high ambient temperatures, part of the required drive energy can be provided by the vehicle's high-voltage battery in order to be able to reduce the power of the fuel cell and thus also the load on the cooling system. However, the battery capacity is limited and the battery's state of charge is variable, so that this possibility exists only in a few use cases or for a limited period of time. It should be noted that the term "battery" is used in the present context in a simplified manner to refer to rechargeable batteries, also known as secondary batteries.

[0004] The cooling system should therefore be dimensioned so that ideally sufficient cooling power is available under all conditions. This results in large dimensions for the cooling system, in particular for the heat exchanger or heat exchangers in the front area of ​​the vehicle. Alternatively, it is also conceivable to reduce the power of the fuel cell under certain conditions (e.g. uphill travel at high ambient temperatures) in order to reduce the cooling requirement. However, this could potentially lead to reduced customer satisfaction.

[0005] From the prior art, many concepts are known which at least indirectly connect cooling circuits and also have an effect on the cooling of the fuel cell.

[0006] DE 10 2015 015 635 A1, DE 10 2018 219 203 A1, DE 10 2009 035 471 A1 and US 9 136 549 B2 disclose thermally coupling a fuel cell cooling circuit to a battery cooling circuit. However, in this case it is not possible to separate the two cooling circuits; instead, they are always coupled to one another. Furthermore, DE 10 2010 032 886 A1 discloses coupling a charge air cooling circuit of a fuel cell to a battery cooling circuit. Summary of the invention

[0007] As described in detail herein, embodiments according to the present disclosure further optimize the cooling of a fuel cell device specifically designed for powering a motor vehicle.

[0008] A first aspect of the present disclosure relates to a cooling system for an apparatus having a fuel cell device and an electrical energy storage device. In this case, the fuel cell device can have one or more fuel cells, for example in the form of a fuel cell stack. The electrical energy storage device can be a battery, such as a high-voltage battery, such as can be used as a drive battery for a motor vehicle, for example.

[0009] The device can be arranged on a motor vehicle, wherein a motor vehicle is understood to mean a vehicle that can be driven by at least one motor, such as a land vehicle, an aircraft or a watercraft. The motor vehicle can be a passenger car or a truck. In other words, the proposed cooling system can be designed for cooling a fuel cell device and a drive battery of a motor vehicle.

[0010] The cooling system has a first cooling circuit designed to cool the fuel cell device, and a second cooling circuit designed to cool the electrical energy storage device. In this case, the first cooling circuit and the second cooling circuit can be directly fluidly connected to each other. In this context, direct fluid connection means that the two cooling circuits can be coupled to each other in such a way that the same coolant can flow at least in parts of the two cooling circuits. As explained in more detail below, being able to connect or being able to couple is understood to mean that the two cooling circuits can be separated or that the two cooling circuits can be coupled or connected.

[0011] For example, a direct fluid connection can be realized via a coolant line which can convey coolant from the first cooling circuit from a removal point to the second cooling circuit and from the second cooling circuit to a recirculation point in the first cooling circuit.

[0012] The coolant used in both cooling circuits can be, for example, a water / glycol mixture, optionally equipped with additives, which meets the requirements of both cooling circuits. When starting a cooling circuit or multiple cooling circuits, the coolant flows through the respective cooling circuit and can, as the case may be, through the connected cooling circuits.

[0013] As mentioned, the first cooling circuit is designed for cooling the fuel cell device. For example, the first cooling circuit can be used to ensure that the maximum temperature of the fuel cell device measured directly upstream of or at the input of the fuel cell device remains in the range between 55°C and 60°C.

[0014] The first cooling circuit can have a heat exchanger, for example for exchanging heat between the coolant and the ambient air. Advantageously, such a heat exchanger can be arranged in the front region of the motor vehicle equipped with the cooling system to allow the best possible heat dissipation. In order to form and intensify the coolant flow through the first cooling circuit, the first cooling circuit can have a coolant pump, for example a water pump.

[0015] Optionally, a bypass line for bypassing the heat exchanger and a temperature control valve arranged at a branch point of the bypass line (i.e. at a removal point or recirculation point of the bypass line) can be provided. The temperature control valve can be used to influence the temperature of the coolant in a specific area, in which more or less coolant is led through the bypass line instead of being led to the heat exchanger and is cooled to a lower degree as a result. For this purpose, the temperature control valve can be combined with a temperature sensor, which can be arranged, for example, directly upstream of the fuel cell device or at its input and measures the temperature of the coolant and allows the coolant temperature to be controlled. Furthermore, a balancing vessel may optionally be incorporated into the first cooling circuit.

[0016] As mentioned, the second cooling circuit is designed for cooling the electrical energy storage device. For example, the second cooling circuit can be used to ensure that the maximum temperature of the electrical energy storage device remains in the range between 25° C. and 40° C. In order to achieve this temperature of the electrical energy storage device, the temperature of the coolant of the second cooling circuit measured directly upstream of the electrical energy storage device or at its input can, for example, be below 25° C.-30° C. Depending on the cooling concept of the electrical energy storage device, the coolant temperature upstream of the electrical energy storage device can also be significantly below a specified value.

[0017] The second cooling circuit may have a cooler to cool the coolant flowing through the second cooling circuit. The cooler may be used to ensure heat exchange between the coolant and the refrigerant. In other words, the second cooling circuit may have a cooler thermally coupled to the refrigerant circuit.

[0018] As a rule, the refrigerant circuit can have an electric refrigerant compressor and a condenser. An evaporator, for example, which is used to cool the interior of a vehicle, can optionally be integrated into the refrigerant circuit.

[0019] In order to establish and intensify the coolant flow through the second cooling circuit, the second cooling circuit can have a coolant pump, for example a water pump. Optionally, a balancing vessel can be integrated into the second cooling circuit.

[0020] The first cooling circuit and the second cooling circuit may be operated substantially at ambient pressure, ie neither cooling circuit is a refrigerant circuit.

[0021] The possibility of direct fluid connection of the first cooling circuit and the second cooling circuit allows, on the one hand, the fuel cell device and the electrical energy storage device to be cooled separately from one another in the non-connected state. As a result, the required cooling of the electrical energy storage device in particular can be ensured.

[0022] On the other hand, in the connected state, additional cooling of the fuel cell arrangement is made possible by the cooling capacity of the second cooling circuit (for example by using a cooler arranged on the second cooling circuit). This can also allow the fuel cell arrangement to be operated at a higher power, which would otherwise either not be possible or only possible by means of a cooling device with correspondingly large dimensions and an associated large space requirement, due to insufficient cooling of the fuel cell arrangement.

[0023] According to various embodiment variants, a first cooling circuit and a second cooling circuit can be provided which can be operated separately from one another in the first operating mode.

[0024] This first operating mode advantageously allows the fuel cell device and the electrical energy storage device to be cooled independently of one another. Different cooling requirements of the fuel cell device and the electrical energy storage device can thus be met in a simple manner.

[0025] If both the fuel cell device and the electrical energy storage device require cooling, the cooling system can be operated in the first operating mode. In this regard, reference is made to the following explanations.

[0026] According to further embodiment variants, in the second operating mode, the first cooling circuit and the second cooling circuit can be operated coupled to each other without incorporating an electrical energy storage device.

[0027] In other words, a cooling circuit can be formed, which comprises the first cooling circuit, a portion of the second cooling circuit (i.e. a portion into which no electrical energy storage device is incorporated) and a connecting line between the first cooling circuit and the second cooling circuit. For this purpose, corresponding branching points in the first cooling circuit and the second cooling circuit can be provided, which branching points are appropriately equipped with one or more flow control valves.

[0028] If a cooler of the second cooling circuit is coupled to the refrigerant circuit, this cooler can therefore preferably be activated or become active in the second operating mode.

[0029] The second operating mode advantageously allows the cooling capacity of the second cooling circuit to be used for cooling the fuel cell device. By appropriately adding coolant in the second cooling circuit, which is cooled significantly compared to the coolant in the first cooling circuit, the temperature of the coolant just upstream of the fuel cell device can be adjusted as required (i.e. as per the necessary cooling requirement, which depends among other things on the current power of the fuel cell device). For example, the temperature of the coolant can be reduced by a further 5 to 10 K.

[0030] According to further embodiment variants, the cooling system may have a control unit which is configured and designed to generate a control signal which causes the cooling system to operate in the first operating mode or in the second operating mode.

[0031] The control unit can be implemented in the form of hardware and / or software and can be physically in a single-piece or multi-piece form. In particular, the control unit can be part of the drive controller or integrated into the drive controller. The control unit has an operating signal connection with one or more actuators (e.g. flow control valves) of the cooling circuit to be able to transmit the generated control signals to the actuator and thus control the operation of the cooling system.

[0032] The control unit allows selective operation of the cooling system in a first operating mode or in a second operating mode. Optionally, other operating modes may be provided.

[0033] The control unit can be configured and designed to generate a control signal based on the temperature of the energy storage device and the temperature of the fuel cell device. In other words, the control unit can selectively select the first operating mode or the second operating mode based on the temperature of the energy storage device and the fuel cell device.

[0034] For this purpose, the control unit can receive sensor signals from temperature sensors measuring the temperature of the fuel cell device and / or the electrical energy storage device, process these sensor signals based on instructions or coding programmed in the control unit and corresponding to one or more routines, and transmit control signals to one or more drivers of the cooling system. The temperature sensors for measuring the temperature of the fuel cell device and the electrical energy storage device can, for example, be part of the proposed cooling system. It is also possible to directly measure the temperature of the electrical energy storage device (e.g. the temperature of the battery cells) using temperature sensors which are correspondingly arranged on or in the electrical energy storage device.

[0035] Optionally, the control unit may take into account at least one influencing factor when generating the control signal. In this case, the influencing factor may be selected from the group consisting of: the state of charge of the electrical energy storage device, the speed of the motor vehicle equipped with the cooling system, the ambient temperature, the required driving power of the motor vehicle equipped with the cooling system, and the opening position of the coolant valve.

[0036] In other words, one or more influencing factors other than the temperature of the fuel cell device and the energy storage device can be used to make a decision about operating the cooling system in the first operating mode or the second operating mode, generate a corresponding control signal, and output the control signal to a driver of the cooling system.

[0037] According to further embodiment variants, a removal point can be provided for the cooling medium from the first cooling circuit, which is arranged downstream of a heat exchanger located in the first cooling circuit and upstream of the fuel cell arrangement to be cooled.

[0038] This means that when the first cooling circuit and the second cooling circuit are connected, ie in the second operating mode, the coolant previously cooled by the heat exchanger in the first cooling circuit is conducted into the second cooling circuit and further cooled there, for example by a cooler arranged in the second cooling circuit and operating together with the refrigerant circuit.

[0039] Alternatively or in addition, the removal point for the cooling medium from the first cooling circuit can be arranged downstream of the fuel cell device to be cooled and upstream of the heat exchanger located in the first cooling circuit. The removal point can be arranged downstream of the temperature control valve at the branching point of the bypass line for bypassing the heat exchanger of the first cooling circuit.

[0040] This means that when the first cooling circuit and the second cooling circuit are connected (that is to say in the second operating mode), the coolant heated by contact with the fuel cell arrangement is first conducted to the second cooling circuit and cooled there, for example by a cooler arranged in the second cooling circuit and operating with the refrigerant circuit. Here, the coolant supplied to the cooler thus has a higher temperature than the temperature of the coolant in the previously described variants.

[0041] The position of the removal point may depend, among other things, on operating parameters of the cooler, such as its input temperature range. Both described possibilities for the removal point position allow optimizing the cooling capacity of the fuel cell arrangement, in particular to be adapted to the specific operating parameters of the cooler.

[0042] According to further embodiment variants, the recirculation point for the cooling medium into the first cooling circuit can be arranged downstream of a heat exchanger located in the first cooling circuit and upstream of the fuel cell arrangement to be cooled.

[0043] This allows efficient cooling of the fuel cell arrangement, since the supplied coolant cooled in the second cooling circuit is ideally recirculated directly upstream of the fuel cell arrangement into the first cooling circuit.

[0044] Another aspect of the present disclosure relates to a motor vehicle having a fuel cell device, an electrical energy storage device and a cooling system as described above.

[0045] Therefore, the statements above for explaining the proposed cooling system also apply to the description of the motor vehicle. The advantages of the cooling system are correspondingly relevant to the motor vehicle.

[0046] Another aspect of the present disclosure relates to a method for cooling a fuel cell device by a cooling system as described above, wherein the cooling system operates in a first operating mode if the energy storage device needs to be cooled, and wherein the cooling system operates in a second operating mode if the energy storage device does not need to be cooled.

[0047] The proposed method is carried out by means of the cooling system explained above. In this respect, the statements above for explaining the cooling system also serve to describe the proposed method. The advantages of the cooling system are accordingly relevant to the method. For example, the method can be carried out in a motor vehicle equipped with a corresponding cooling system, a fuel cell device and an electrical energy storage device.

[0048] For further explanation of the conditions under which an energy storage device may or may not require cooling, please refer to the following statement: The energy storage device may not require cooling if the temperature of the energy storage device is already low enough without cooling and / or if the state of charge of the energy storage device is too low for further use and therefore the energy storage device is deactivated.

[0049] According to different embodiment variants, it is possible that the power of the fuel cell arrangement can be varied depending on the operation of the cooling system in the first operating mode or in the second operating mode.

[0050] For example, operation of the cooling system in the second operating mode may involve a higher power of the fuel cell device than operation of the cooling system in the first operating mode. In other words, the power of the fuel cell device in the second operating mode may be higher than the power of the fuel cell device in the first operating mode.

[0051] The possibility to increase the power of the fuel cell arrangement in the second operating mode compared to the first operating mode may allow the fuel cell arrangement to fully or almost fully meet the power demand even under difficult operating conditions (eg high ambient temperature, uphill driving etc.).

[0052] Further advantages are apparent from the accompanying drawings and the associated description, based on which representative embodiments of the claimed subject matter will be explained in more detail below. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 A schematic diagram showing a cooling system with a cooling circuit according to the prior art; Figure 2 A schematic diagram showing a cooling system according to an embodiment of the present disclosure; Figure 3 In the first operating mode, Figure 2 A cooling system of an embodiment; Figure 4 In the second operating mode, Figure 2 A cooling system of an embodiment; Figure 5 A schematic diagram showing a cooling system according to another embodiment of the present disclosure; Figure 6 A flow chart showing a method for controlling or operating a cooling system according to the present disclosure; Figure 7 Explain that fuel cell devices and electrical energy storage devices may be able to meet the power requirements; and Figure 8 is a schematic diagram of a representative motor vehicle according to one or more embodiments of the present disclosure. DETAILED DESCRIPTION

[0054] As required, specific embodiments are disclosed herein; however, it is to be understood that the disclosed embodiments are merely representative and may be embodied in various alternative forms. The drawings are not necessarily drawn to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, the specific structural and functional details disclosed herein are not to be construed as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the claimed subject matter.

[0055] Figure 1 A cooling system 1 according to the prior art is shown, which can be used, for example, in a motor vehicle 100, the driving energy of which can be obtained from a fuel cell device 2 and an electrical energy storage device 3 (i.e., a battery). Both the fuel cell device 2 and the electrical energy storage device 3 generally need to be cooled in order not to exceed an upper temperature limit FC of the fuel cell device, respectively. Thresh And the upper temperature limit of the energy storage device Batt Thresh .

[0056] According to the prior art, separate cooling circuits are provided for cooling purposes, namely a first cooling circuit 4 for cooling the fuel cell device 2 and a second cooling circuit 5 for cooling the electrical energy storage device 3. The fuel cell device 2 and the electrical energy storage device 3 are thus cooled completely independently of one another.

[0057] The first cooling circuit 4 is formed by a coolant line 21a, which connects the individual devices of the first cooling circuit 4 to each other and through which the coolant flows. In order to form a flow of coolant in the first cooling circuit 4, the first cooling circuit has a coolant pump 14a. In addition, a heat exchanger 12 that allows heat exchange between the coolant and the environment is arranged in the first cooling circuit 4. The heat exchanger 12 therefore takes the form of a coolant-air heat exchanger. The heat exchanger 12 can be arranged in the front area of ​​the motor vehicle 100 to allow heat to be dissipated to the environment as well as possible with as little influence as possible from other heat exchangers present in the motor vehicle 100.

[0058] The first cooling circuit 4 may additionally have a bypass line 22 for bypassing the heat exchanger 12. The temperature control valve 18 may be used to determine whether and how much coolant flows through the bypass line 22 and therefore cannot be cooled by the heat exchanger 12. The temperature control valve 18 may be arranged in the first cooling circuit 4, for example. Figure 1 The position shown (i.e., at the branch point of the bypass line 22). Therefore, the temperature of the coolant in the first cooling circuit 4 can be controlled within a certain range by adjusting the valve position of the temperature control valve 18. Optionally, a balancing tank (not shown) can be provided in the first cooling circuit 4.

[0059] The second cooling circuit 5 is formed by a coolant line 21b, which connects the various devices of the second cooling circuit 5 to each other and through which the coolant flows. The second cooling circuit 5 includes a coolant pump 14b. Optionally, a balancing tank (not shown) can also be provided in the second cooling circuit 5.

[0060] Furthermore, a cooler 10 is provided in the second cooling circuit 5, which is thermally coupled to the refrigerant circuit 9 and allows heat exchange between the coolant and the refrigerant flowing through the refrigerant circuit 9. The cooler 10 thus takes the form of a coolant-refrigerant heat exchanger. By thermally coupling the second cooling circuit 5 to the refrigerant circuit 9 via the cooler 10, a stronger cooling of the coolant in the second cooling circuit 5 compared to the coolant in the first cooling circuit 4 is possible. As a result, the temperature T FC Compared with the conventional energy storage device, a lower temperature T Batt .

[0061] The refrigerant circuit 9, which is thermally coupled to the second cooling circuit 5, is constructed in a conventional manner. The refrigerant circuit 9 has a refrigerant compressor 17 and a condenser 16 as well as a refrigerant valve 20, and the working principle of the refrigerant circuit 9 is known to those skilled in the art. In addition, an evaporator 15 is provided, which can be arranged, for example, in the interior of the motor vehicle 100 and can be used for air conditioning, in particular cooling, in the vehicle interior.

[0062] As described previously, according to the prior art, the two cooling circuits 4, 5 are designed to be always separate from each other. This has the consequence that if the fuel cell device 2 is not sufficiently cooled, its power is reduced or at least cannot be increased in order not to exceed the upper temperature limit FC of the fuel cell device. ThreshThis can have a negative effect, for example, when it is no longer possible to drive the motor vehicle 100 by means of the electrical energy storage device 5 because the state of charge of the electrical energy storage device 5 is no longer sufficient. In order to maintain the required drive power for the motor vehicle 100, the loss proportion of the electrical energy storage device 5 will have to be compensated by the fuel cell device 2, which generally leads to an increase in the temperature T of the fuel cell device. FC The rise and therefore the higher cooling requirement, however, cannot be met by the first cooling circuit 4 alone.

[0063] In order to be able to increase the cooling of the fuel cell device 2 in the above-described situation, among other things, an improvement of the cooling system 1 is provided according to the present disclosure. Figure 2 A first representative embodiment of such an improved cooling system 1' is shown in the schematic diagram. Figure 1 The difference between the cooling system 1 and the cooling system 2; for other aspects, refer to Figure 1 explanation.

[0064] Figure 2 The cooling system 1 ' of FIG. 1 is distinguished in that the first cooling circuit 4 and the second cooling circuit 5 can be directly fluidically connected to one another. For this purpose, a supply line 23 and a recirculation line 24 are provided, which guide the coolant as required from a removal point 11 arranged in the first cooling circuit 4 into the second cooling circuit 5 and from the second cooling circuit 5 to a recirculation point 13 arranged in the first cooling circuit 4. The coolant used is water, optionally provided with additives.

[0065] In the first embodiment, the removal point 11 is arranged downstream of the heat exchanger and upstream of the fuel cell device 2. In other words, when the cooling system 1' is operating in the second operating mode B (see explanation of the operating modes below), the heat exchanger 12 and the cooler 10 are arranged parallel to each other with respect to the flow of the coolant.

[0066] The recirculation point 13 is arranged downstream of the heat exchanger 12 and upstream of the fuel cell device 2. Furthermore, in the first exemplary embodiment, the removal point 11 is arranged upstream of the recirculation point 13.

[0067] In order to couple the first cooling circuit 4 and the second cooling circuit 5 to each other as required, i.e. only when special conditions exist, a coolant valve 8 is provided. The coupling of the two cooling circuits 4, 5 as required is achieved by a controller or control unit 6, and the control signal 7 generated and output by the control unit 6 is output to the coolant valve 8 and causes a change in the valve position, i.e. in the open state of the coolant valve 8.

[0068] The controller or control unit 6 can in particular be based on the temperature T Batt and the temperature T of the fuel cell deviceFC Generate control signal 7, as shown below Figure 6 More detailed explanation. In order to determine the temperature T of the energy storage device Batt and the temperature T of the fuel cell device FC A temperature sensor (not shown) may be provided, the sensor signal of which is transmitted to the control unit 6 and processed by the control unit 6. Batt The temperature sensor can be arranged, for example, directly in or on the energy storage device 3 in order to directly measure the temperature of the battery cell. FC A temperature sensor may be arranged, for example, directly upstream of the fuel cell arrangement 2 in the first cooling circuit 4 in order to measure the coolant temperature at the input of the fuel cell arrangement 2 .

[0069] The controller or control unit 6 may be implemented by a programmable microprocessor having stored data and instructions that, when implemented, perform a method for controlling a cooling system or a vehicle having a cooling system 1'. The stored data and instructions may be stored in a volatile memory and / or a non-volatile memory or other non-transitory computer readable storage medium. The instructions of the programmed microprocessor and / or hardware logic control circuit perform one or more control functions or algorithms to control one or more outputs in response to one or more inputs. This may be accomplished, for example, by Figure 6 The flow charts or similar diagrams illustrated in FIG. 1 and described in more detail herein schematically represent control functions or algorithms. exist Figure 2 In the embodiment of the present invention, the coolant valve 8 is in the form of a three-way valve. As a result, depending on the valve position of the coolant valve 8, it can be determined on the one hand whether the first cooling circuit 4 and the second cooling circuit 5 are coupled to each other, and on the other hand whether the electrical energy storage device 3 is incorporated into the cooling circuit. Figure 3 and 4 These are explained in more detail. The function of the coolant valve 8 as a three-way valve can alternatively also be realized by two separate valves.

[0070] Figure 3 Display in the first operating mode A according to Figure 2 In the cooling system 1 ′ of the first embodiment, the first cooling circuit 4 and the second cooling circuit 5 are operated separately from each other in the first operating mode A. The fuel cell device 2 and the electrical energy storage device 3 are therefore cooled independently of each other according to the necessary cooling requirements in each case.

[0071] To activate the first operating mode A, the control unit 6 generates a control signal 7 which is output to the coolant valve 8 and leads to an interruption of the flow through the recirculation line 24 and the merging of the electrical energy storage device 3 into the second cooling circuit 5 .

[0072] Figure 4 Display in the second operation mode B according to Figure 2 In the cooling system 1' of the first embodiment, the first cooling circuit 4 and the second cooling circuit 5 are operated coupled to each other in the second operating mode B, wherein the energy storage device 3 is not integrated into the second cooling circuit 5. This means that on the one hand, the energy storage device is not cooled by the cooling system 1 in the second operating mode B. On the other hand, the fuel cell device 2 is cooled to a higher degree by means of the coolant cooled not only by the heat exchanger 12 but also by the cooler 10.

[0073] In order to activate the second operating mode B, the control unit 6 generates a control signal 7 which is output to the coolant valve 8 and causes the flow through the recirculation line 24 to be enabled and the flow in the direction of the electrical energy storage device 3 to be interrupted. By influencing the flow rate in the recirculation line 24, the mixing temperature of the coolant can be determined so that the cooling requirements of the fuel cell device 2 can be met without unnecessary loading or activation of the refrigerant circuit 9. The flow rate in the recirculation line 24 can likewise be influenced by the control signal 7 which is generated by the control unit 6 and output to the coolant valve 8, by means of which a corresponding change in the valve opening is caused.

[0074] In the second operating mode B, the bypass line 22 can preferably additionally be deactivated or become deactivated, so that all the coolant flows through the heat exchanger 12 and is cooled as much as possible.

[0075] exist Figure 5 In the figure, a second embodiment of the cooling system 1 is schematically illustrated. Only the cooling system ( Figure 2 ) changes; for other aspects, refer to the explanation of the first embodiment. In particular, the cooling system 1 "of the second exemplary embodiment can also be used to implement the two operating modes A and B in a similar manner.

[0076] The cooling system 1 ″ of the second embodiment differs from the cooling system 1 ′ of the first embodiment in the position of the removal point 11. However, the removal point 11 in the first embodiment is arranged downstream of the heat exchanger 12 and upstream of the fuel cell device 2, as shown in FIG. Figure 5 As shown in , the removal point 11 in the second embodiment is arranged downstream of the fuel cell device 2 and upstream of the heat exchanger 12. In other words, when the cooling system 1" is operated in the second operating mode B, the heat exchanger 12 and the cooler 10 are arranged parallel to each other with respect to the flow of the coolant.

[0077] The result of this is that the coolant guided into the second cooling circuit 5 via the supply line 23 in the second operating mode B has a higher temperature than in the first embodiment, since the coolant previously cools the fuel cell device 2 and absorbs heat in the process. Depending on the configuration of the refrigerant circuit 9, this can have a positive effect on the subsequent cooling of the coolant by the cooler 10.

[0078] Figure 6 A flow chart showing a method 200 for cooling a fuel cell device 2 is shown. For example, the first embodiment ( Figure 2 ) of the cooling system 1 'or the second embodiment described above ( Figure 5 )'s cooling system 1" executes method 200.

[0079] In method step S1 , the temperature T of the energy storage device is determined, for example, by one or more temperature sensors in or on the energy storage device 3 or in or on the battery cells. Batt In method step S2, the temperature T of the fuel cell arrangement is determined, for example, by means of a further temperature sensor. FC A further temperature sensor can be arranged, for example, directly upstream of the fuel cell device 2 and determines the temperature of the coolant at this point, from which the temperature T of the fuel cell device can be inferred. FC .

[0080] In method step S3, it is checked whether the energy storage device 3 needs to be cooled. For this purpose, for example, the temperature T of the energy storage device can be determined. Batt Whether the temperature limit of the energy storage device is exceeded Batt Thresh , that is, T Batt >Batt Thresh Is it true? The upper temperature limit of the energy storage device Batt Thresh For example, it may be in the range between 30° C. and 45° C., in particular in the range between 35° C. and 40° C., for example, the upper temperature limit Batt Thresh When the temperature of the energy storage device exceeds the upper limit Batt Thresh When the normal operation of the energy storage device 2 is no longer guaranteed, the cooling should be below the upper temperature limit Batt Thresh If it is determined in method step S3 that the energy storage device 3 needs to be cooled, that is, T Batt >Batt Thresh If true, the method 200 then continues to method step S4.

[0081] In method step S4, the cooling system 1' or 1" is operated in the first operating mode A. In other words, the first cooling circuit 4 and the second cooling circuit 5 are operated separately from each other. Therefore, the electrical energy storage device 3 can be cooled sufficiently. The method 200 can then continue with method step S1 again, i.e., T can be continuously checked. Batt >Batt Thresh whether this is true and whether the energy storage device 3 needs to be cooled.

[0082] If, on the other hand, it is determined in method step S3 that the electrical energy storage device 3 does not need to be cooled, that is to say T Batt >Batt Thresh If not, the method 200 continues with method step S5 .

[0083] In method step S5, it is checked whether the fuel cell system 2 needs to be cooled. For this purpose, for example, the temperature T of the fuel cell system can be determined. FC Whether the temperature limit of the fuel cell device is exceeded Thresh , that is, T FC >FC Thresh Is it true? The upper temperature limit of the fuel cell device FC Thresh For example, the upper temperature limit FC of the fuel cell device may be in the range between 50° C. and 65° C., in particular in the range between 55° C. and 60° C. Thresh When the temperature of the fuel cell device exceeds the upper limit FC Thresh When the temperature is lower than the upper limit FC, the normal operation of the fuel cell device 2 is no longer guaranteed. Therefore, the cooling should be performed at a temperature lower than the upper limit FC. Thresh Alternatively or in addition, the power of the fuel cell device 2 can be reduced to facilitate cooling. If it is determined in method step S5 that the fuel cell device 2 needs to be cooled, that is, T FC >FC Thresh If true, the method 200 then continues to method step S6.

[0084] In method step S6, the cooling system 1' or 1" is operated in the second operating mode B. In other words, the first cooling circuit 4 and the second cooling circuit 5 are coupled to each other, wherein the electrical energy storage device 3 is not combined and is therefore no longer cooled. In a representative embodiment, the cooler 10 of the second cooling circuit 5 is enabled, i.e. the refrigerant circuit 9 is in the active state or becomes active. In the second operating mode B, the fuel cell device 2 is cooled to a greater extent, since the coolant is cooled not only by the heat exchanger 12 but also additionally by the cooler 10. The method 200 can then continue with method step S1 again, i.e. the T can be continuously checked. Batt >Batt Thresh Whether it is established and whether the electric energy storage device 3 needs to be cooled.

[0085] If, on the other hand, it is determined in method step S5 that the electrical energy storage device 3 does not need to be cooled, that is to say T Batt >Batt Thresh If not, the method 200 continues with method step S7 .

[0086] In method step S7, the chiller 10 is deactivated, for example by means of the refrigerant circuit becoming deactivated. The method can then continue with method step S1.

[0087] Method steps S1 and S2 can also be performed in reverse order or at least partially in parallel in time, in particular, method steps S1 and S2 can also be performed continuously. In addition, method step S2 can also be performed at a later time point, requiring the temperature T of the fuel cell device at this later time point to be FC The method 200 is further executed, that is, for example, when method step S3 indicates T Batt >Batt Thresh When established.

[0088] Except the temperature T of the energy storage device Batt and the temperature T of the fuel cell device FC In addition, further influencing factors may be taken into account when deciding whether the cooling system 1', 1" is to be operated in the first operating mode A or in the second operating mode B. Such possible further influencing factors are the state of charge of the electrical energy storage device 3, the speed of the motor vehicle 100 equipped with the cooling system 1, the ambient temperature, the required driving power of the motor vehicle 100 and the opening position of the coolant valve 8. Including one or more of these influencing factors allows a more stable control of the coolant temperature to be achieved.

[0089] Reference below Figure 7 The influencing factors that may be involved are explained in more detail: the state of charge of the electrical energy storage device 3 and the required drive power of the motor vehicle 100 .

[0090] exist Figure 7 In the diagram, an uphill trip of a motor vehicle 100 equipped with a cooling system 1', 1" is considered, wherein the motor vehicle 100 can be driven by the energy storage device 3 or the fuel cell device 2 or by the energy storage device 3 and the fuel cell device 2 in a combined manner. The distance or duration of the uphill trip is plotted on the x-axis; the driving power of the motor vehicle 100 is plotted on the y-axis. The simplifying assumption is that a constant driving power is required for the entire uphill trip. The required driving power can be met by the power of the fuel cell device 2 and / or the power of the energy storage device 3, i.e. the power of the fuel cell device 2 and the power of the energy storage device 3 together meet the required driving power.

[0091] At the beginning of the uphill journey, the cooling system is operated in the first operating mode A, i.e. with separate cooling circuits 4, 5. The available power of the fuel cell device 2 is limited in this case by the cooling of the fuel cell device 2, that is to say the performance of the first cooling circuit 4. Since the energy storage device 3 is sufficiently cooled in the first operating mode A, the energy storage device 3 can make a partial contribution to the drive power. In other words, during the duration of the first operating mode A, the drive power of the motor vehicle 100 is met by the fuel cell device 2 and the energy storage device 3.

[0092] As the distance or duration increases, the state of charge of the energy storage device 3 decreases. At time point X or after completing distance X, the lower limit of the state of charge is reached (eg 5% remaining capacity) and the energy storage device 3 is deactivated and the associated power supply is reduced to zero.

[0093] If the cooling system continues to operate in the first operating mode A, the power provided by the electrical energy storage device 2 will disappear and it will therefore no longer be possible to meet the necessary drive power of the motor vehicle 100. Therefore, the cooling system operates in the second operating mode B starting from point X.

[0094] Since a higher cooling power is available in the second operating mode B for cooling the fuel cell device 2, the power of the fuel cell device 2 can be increased so that the required driving power can be fully or almost fully met by the fuel cell device 2. In other words, the power of the fuel cell device 2 can be changed according to the operation of the cooling system in the first operating mode A or the second operating mode B.

[0095] Figure 8 A schematic block diagram of a motor vehicle 100 is shown. The motor vehicle 100 is in the form of a passenger car and has a fuel cell device 2 and an electrical energy storage device 3, which individually or together provide the drive power of the motor vehicle 100. The fuel cell device 2 and the electrical energy storage device 3 are cooled by a cooling system 1', 1", which is designed according to the first or second embodiment and allows cooling in a first operating mode A or a second operating mode B.

[0096] The proposed cooling system and the associated method allow for increasing the cooling capacity of the cooling device of the fuel cell device 2 by incorporating the cooling device of the electrical energy storage device 3, so that the fuel cell device 2 can be operated at a higher power without reducing the driving power of the motor vehicle due to insufficient power of the fuel cell device 2. Alternatively, for a constant power of the fuel cell device 2, its cooling device can be smaller in size, so that installation space can be saved. Optimization between these two variants is also possible.

[0097] Although representative embodiments are described above, these embodiments are not intended to describe all possible forms of the claimed subject matter. The words used in the specification are descriptive rather than restrictive, and it should be understood that various changes can be made without departing from the spirit and scope of the claimed subject matter. In addition, the features of different embodiments can be combined to form more embodiments that may not be explicitly illustrated or described.

Claims

1. A vehicle comprising: Fuel cells; an electrical energy storage device electrically connected to the fuel cell; a first cooling circuit configured to circulate a liquid coolant through the fuel cell; a second cooling circuit configured to circulate the liquid coolant through the electrical energy storage device; at least one controllable valve selectively coupling the first cooling circuit and the second cooling circuit; as well as A controller in communication with the at least one controllable valve, the controller being programmed to control the at least one controllable valve to fluidly separate the first cooling circuit and the second cooling circuit when operating in a first mode and to fluidly connect the first cooling circuit and the second cooling circuit when operating in a second mode.

2. The vehicle according to claim 1, wherein: The controller is programmed to operate the at least one controllable valve in the first mode or in the second mode in response to a temperature of the electrical energy storage device and a temperature of the fuel cell.

3. The vehicle according to claim 2, wherein: The first cooling circuit includes a heat exchanger configured to exchange heat between a coolant of the first cooling circuit and ambient air.

4. The vehicle according to claim 3, wherein: The first cooling circuit includes a coolant pump.

5. The vehicle according to claim 3, further comprising: a bypass line configured to bypass the heat exchanger; a temperature control valve disposed at a branch point of the bypass line; as well as a temperature sensor disposed directly upstream of the fuel cell and configured to measure the temperature of the coolant; The controller is programmed to control the temperature control valve to control coolant flowing through the bypass line in response to a signal from the temperature sensor.

6. The vehicle according to claim 5, wherein: The first cooling circuit includes a balancing vessel.

7. The vehicle according to claim 5, wherein: The second cooling circuit includes a chiller configured to exchange heat between a coolant and a refrigerant of the second cooling circuit.

8. The vehicle according to claim 7, wherein: The second cooling circuit includes a coolant pump.

9. The vehicle according to claim 7, wherein: The controller is programmed to operate the at least one controllable valve to fluidly couple the first cooling circuit and the second cooling circuit while bypassing the electrical energy storage device. 10 . The vehicle of claim 7 , further comprising a second temperature sensor in communication with the controller, the second temperature sensor disposed in the second cooling circuit and configured to measure a temperature of a coolant flowing through the electrical energy storage device.

11. The vehicle according to claim 7, wherein: The controller is further programmed to operate in the first mode or in the second mode further in response to at least one of: a state of charge of the electrical energy storage device, a speed of the vehicle, an ambient temperature, and a desired drive power of the vehicle.

12. The vehicle according to claim 7, wherein: The first cooling circuit includes a coolant removal point disposed downstream of the heat exchanger and upstream of the fuel cell such that coolant passing through the heat exchanger is directed into the second cooling circuit upstream of the cooler.

13. The vehicle according to claim 7, wherein: The first cooling circuit comprises a coolant recirculation point arranged downstream of the heat exchanger and upstream of the fuel cell.

14. A vehicle comprising: Fuel cells; an electrical energy storage device electrically connected to the fuel cell; a first cooling circuit configured to circulate a liquid coolant through the fuel cell; a heat exchanger configured to exchange heat between the coolant of the first cooling circuit and ambient air; a second cooling circuit configured to circulate the liquid coolant through the electrical energy storage device; a chiller configured to exchange heat between the coolant and the refrigerant of the second cooling circuit; at least one controllable valve selectively coupling the first cooling circuit and the second cooling circuit; as well as a controller in communication with the at least one controllable valve, the controller being programmed to control the at least one controllable valve to fluidly separate the first cooling circuit and the second cooling circuit when operating in a first mode and to fluidly connect the first cooling circuit and the second cooling circuit when operating in a second mode, the controller operating the first cooling circuit and the second cooling circuit in one of the first mode and the second mode in response to a temperature of a coolant flowing through the fuel cell and a temperature of a coolant flowing through the electrical energy storage device.

15. The vehicle of claim 14, further comprising a coolant removal point disposed downstream of the fuel cell and upstream of the heat exchanger.

16. The vehicle of claim 15, further comprising a coolant recirculation point disposed downstream of the heat exchanger and upstream of the fuel cell.

17. The vehicle of claim 16, further comprising: a bypass line configured to bypass the heat exchanger; a temperature control valve disposed at a branch point of the bypass line; as well as a temperature sensor disposed directly upstream of the fuel cell and configured to measure the temperature of the coolant at the input of the fuel cell; The controller is programmed to control the temperature control valve to control coolant flow through the bypass line in response to a signal from the temperature sensor.

18. The vehicle of claim 17, wherein: The controller is programmed to operate the at least one controllable valve to fluidly couple the first cooling circuit and the second cooling circuit while bypassing the electrical energy storage device.

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