Fuel cell system and operating method for operating a fuel cell system
Patent Information
- Application Number
- PCT/EP2025/054092
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2024-03-07
- Filing Date
- 2025-02-14
- Publication Date
- 2025-10-02
AI Technical Summary
Existing fuel cell systems face challenges in achieving compactness and efficient power output while accommodating varying power requirements and system states, particularly due to the need for multiple sub-modules and non-uniform aging of partial fuel cell systems.
A fuel cell system design comprising multiple partial fuel cell systems, each with subassemblies for symmetrical and asymmetrical operation, utilizing central and individual adjustments of operating parameters like anode recirculation, hydrogen concentration, and water balance, facilitated by a computing unit for adaptive operation.
Enables a compact fuel cell system with efficient power output adaptation and uniform aging, minimizing sub-module requirements and optimizing system performance based on power demands and states.
Smart Images
Figure EP2025054092_02102025_PF_FP_ABST
Abstract
Description
[0001] Description
[0002] The presented invention relates to an operating method for operating a fuel cell system and a fuel cell system according to the appended claims.
[0003] State of the art
[0004] Fuel cell systems convert oxygen and hydrogen into water and electrical power.
[0005] Fuel cell systems are known that comprise several fuel cell stacks in order to be able to provide particularly high performance, for example.
[0006] Disclosure of the invention
[0007] Within the scope of the invention presented, a fuel cell system and an operating method for operating the fuel cell system are presented. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the operating method according to the invention naturally also apply in connection with the fuel cell system according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other. The invention presented serves, in particular, to provide a possibility for a compact fuel cell system.
[0008] Thus, according to a first aspect of the invention presented, an operating method for operating a fuel cell system is presented, wherein the fuel cell system comprises a plurality of partial fuel cell systems and a number of system assemblies, each of which is configured to jointly operate all of the partial fuel cell systems of the plurality of partial fuel cell systems, each partial fuel cell system comprising a number of subassemblies, each of which is configured to specifically operate only one respective partial fuel cell system.
[0009] The presented operating method comprises operating the plurality of partial fuel cell systems in a symmetrical operating mode, in which each partial fuel cell system is operated at a centrally predetermined system operating point, and / or operating the plurality of partial fuel cell systems in an asymmetrical operating mode, in which each partial fuel cell system is operated at an individual operating point.
[0010] In the context of the invention presented, a partial fuel cell system is understood to mean a part of a fuel cell system with a plurality of fuel cell stacks, which comprises a fuel cell stack and a number of assemblies for operating the fuel cell stack.
[0011] The presented operating method is based on a symmetrical operating mode, in which the respective sub-fuel cell systems of the presented fuel cell system are operated at the same or centrally specified operating point. For this purpose, for example, the respective subassemblies can be configured or adjusted identically according to the specified operating point, so that the same operating point, in particular the same power output, is achieved in the various sub-fuel cell systems.
[0012] The reverse sequence can also be used, with asymmetric operation first, followed by symmetric operation. The sequence can be selected, for example, based on the externally requested power of the fuel cell system and the state of the individual stacks.
[0013] In particular, according to the operating method presented, it is provided that the various partial fuel cell systems are operated equally via the system modules, for example by setting an identical anode recirculation rate for all partial fuel cell systems via a central anode recirculation blower system module.
[0014] Accordingly, the presented fuel cell system can be designed to be particularly compact by using system modules and symmetrical operation, since the number of sub-modules required multiple times is minimized.
[0015] It can be provided that the subassemblies are used to adjust a mass flow of at least one operating medium through an anode subsystem of a respective partial fuel cell system, wherein the subassemblies of each partial fuel cell system comprise at least one assembly from the following list of subassemblies: anode recirculation blower, jet pump, anode control valve, anode recirculation valve.
[0016] By individually adjusting the mass flow of, for example, hydrogen or hydrogen-containing fluid through a respective anode subsystem, i.e., a partial fuel cell system-specific adjustment, the power provided by a respective partial fuel cell system can be adapted to the power provided by another partial fuel cell system or adjusted independently of the other partial fuel cell system. Accordingly, subassemblies for adjusting the mass flow of, for example, hydrogen or hydrogen-containing fluid through a respective anode subsystem enable both a symmetrical operating mode and an asymmetrical operating mode.
[0017] It can further be provided that the subassemblies are used to adjust a water discharge from a respective sub-fuel cell system, wherein the subassemblies of each sub-fuel cell system comprise at least one assembly from the following list of subassemblies: water drain valve, water separator.
[0018] By individually adjusting the water balance of a partial fuel cell system, i.e., a partial fuel cell system-specific setting, an operating point of the partial fuel cell system can be adapted to an operating point of another partial fuel cell system or set independently of the other partial fuel cell system. Accordingly, subassemblies for adjusting the water balance enable both a symmetrical operating mode and an asymmetrical operating mode.
[0019] It can further be provided that the subassemblies are used to adjust a specific hydrogen concentration in a respective sub-fuel cell system, wherein the subassemblies of each sub-fuel cell system comprise at least one assembly from the following list of subassemblies: hydrogen dosing valve, anode control valve at the anode inlet, anode control valve at the anode outlet.
[0020] By individually adjusting the hydrogen concentration in a respective anode subsystem, i.e., a fuel cell subsystem-specific setting, the power provided by a respective fuel cell subsystem can be adapted to the power provided by another fuel cell subsystem or adjusted independently of the other fuel cell subsystem. Accordingly, subassemblies for adjusting the hydrogen concentration in a respective anode subsystem enable both a symmetrical operating mode and an asymmetrical operating mode.
[0021] It can further be provided that the system assemblies are used to jointly adjust a mass flow of at least one operating medium through all partial fuel cell systems, wherein the system assemblies comprise at least one central assembly from the following list of central assemblies: anode recirculation blower, jet pump, water separator, hydrogen metering valve in a bypass line. By using central system assemblies, the operating conditions of each partial fuel cell system are adjusted centrally, and the installation space requirements of the proposed fuel cell system are minimized.
[0022] In particular, by using a hydrogen dosing valve in a bypass line, which is used in addition to a main hydrogen dosing valve in a main line, a hydrogen mass flow can be provided which is greater than the maximum hydrogen mass flow required by only a single partial fuel cell system.
[0023] It may further be provided that switching between the asymmetric operating mode and the symmetric operating mode takes place depending on a provided power requirement or a system state.
[0024] In addition to a power requirement, the system state of the respective fuel cell systems can be used as a switching criterion. For example, if the respective system states of the fuel cell systems are comparable, symmetrical operation is appropriate. For non-comparable or asymmetrical states, such as different temperatures, humidity, pressure, or liquid water quantities, asymmetrical operation may be appropriate.
[0025] According to a second aspect, the presented invention relates to a fuel cell system for converting energy. Advantages described in detail for the operating method for operating a fuel cell system according to the first aspect of the invention equally apply to the fuel cell system for converting energy according to the second aspect of the invention.
[0026] The presented fuel cell system comprises a plurality of partial fuel cell systems, wherein each partial fuel cell system comprises a number of subassemblies, each of which is configured to specifically operate only a respective partial fuel cell system, a number of system assemblies, each of which is configured to jointly operate all partial fuel cell systems of the plurality of partial fuel cell systems, and a computing unit, wherein the computing unit is configured to carry out a possible embodiment of the presented operating method.
[0027] In the context of the invention presented, a computing unit is understood to mean a computer, a processor, a control unit or any other programmable circuit.
[0028] It can be provided that the computing unit is configured to operate the plurality of partial fuel cell systems in a symmetrical operating mode and to operate each partial fuel cell system at a centrally predetermined system operating point, and / or to operate the plurality of partial fuel cell systems in an asymmetrical operating mode and to operate each partial fuel cell system at an individual operating point.
[0029] By operating the partial fuel cell systems at a centrally specified system operating point, particularly fuel-efficient operation of the fuel cell system can be achieved.
[0030] By operating the partial fuel cell systems at individual operating points, a particularly uniform aging of the various partial fuel cell systems can be achieved.
[0031] It can further be provided that the fuel cell system comprises, as subassemblies of each sub-fuel cell system, at least one assembly from the following list of subassemblies: anode recirculation blower, jet pump, anode control valve, anode recirculation valve, water drain valve, water separator, hydrogen dosing valve, anode control valve at the anode inlet, anode control valve at the anode outlet.
[0032] In particular, individually adjusting the water balance and / or fluid flow through an anode subsystem of a respective partial fuel cell system has proven beneficial for the service life of the partial fuel cell system. Furthermore, the fuel cell system may comprise at least one central component from the following list of central components: anode recirculation blower, jet pump, water separator, and hydrogen metering valve in a bypass line.
[0033] In particular, assemblies for adjusting a water balance and / or a hydrogen mass flow require particularly large installation space, so that their design as system assemblies leads to a particularly compact fuel cell system.
[0034] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.
[0035] Identical features are marked with the same reference symbols.
[0036] They show schematically:
[0037] Figure 1 shows a possible design of the presented operating procedure,
[0038] Figure 2 shows a representation of a first possible design of the presented fuel cell system,
[0039] Figure 3 shows a second possible embodiment of the fuel cell system presented,
[0040] Figure 4 shows a representation of a fourth possible embodiment of the presented fuel cell system with several subassemblies,
[0041] Figure 5 shows a representation of a fifth possible embodiment of the presented fuel cell system with several subassemblies, and Figure 6 shows an overview of possible embodiments of the presented fuel cell system.
[0042] Figure 1 shows an operating method 100 for operating a fuel cell system.
[0043] The fuel cell system comprises a plurality of sub-fuel cell systems and a number of system assemblies, each configured to jointly operate all of the sub-fuel cell systems of the plurality of sub-fuel cell systems, wherein each sub-fuel cell system comprises a number of sub-assemblies, each configured to specifically operate only a respective sub-fuel cell system.
[0044] The operating method 100 comprises a first operating step 101 in which the plurality of partial fuel cell systems is operated in a symmetrical operating mode in which each partial fuel cell system is operated at a centrally predetermined system operating point, and / or a second operating step 103 in which the plurality of partial fuel cell systems is operated in an asymmetrical operating mode in which each partial fuel cell system is operated at an individual operating point.
[0045] Figure 2 shows a fuel cell system 200 for converting energy.
[0046] The fuel cell system 200 includes a first sub-fuel cell system 201, which includes a first fuel cell stack 203 and a first water separation system 205.
[0047] Furthermore, the fuel cell system 200 of a second partial fuel cell system 207 comprises a second fuel cell stack 209 and a second water separation system 211.
[0048] By means of the two water separation systems 205 and 211, the first partial fuel cell system 201 and the second partial fuel cell system 207 can be dewatered independently of one another or subjected to a purge and / or draining process.
[0049] The first partial fuel cell system 201 and the second partial fuel cell system 207 are supplied with hydrogen from a tank 215 via a system assembly in the form of a hydrogen metering valve 213.
[0050] A central anode recirculation blower 217 is used to recirculate anode gas through the first sub-fuel cell system 201 and the second sub-fuel cell system 207.
[0051] Figure 3 shows the fuel cell system 200 in a configuration in which a further system component in the form of an additional hydrogen metering valve 219 is provided in a bypass line 221 that bypasses a jet pump 223. Accordingly, a particularly large load spread or a particularly small hydrogen mass flow and a particularly large hydrogen mass flow are possible.
[0052] In Figure 4, the fuel cell system 200 is shown in a configuration in which an additional recirculation fan 225 is provided so that a recirculation rate of the first partial fuel cell system 201 can be adjusted independently of a recirculation rate of the second partial fuel cell system 207.
[0053] In Figure 5, the fuel cell system 200 is shown in a configuration in which an additional valve 227 is provided for controlling a recirculation flow through the second partial fuel cell system 207.
[0054] Furthermore, an additional dosing system 229 is provided for adjusting a hydrogen mass flow through the second partial fuel cell system 207.
[0055] Figure 6 shows an overview 300 of possible configurations of the presented fuel cell system. V_dot represents auxiliary units for adjusting a mass flow of a hydrogen-containing fluid through a respective anode subsystem, Drain represents auxiliary units for adjusting a water balance, x_H2 / p_H2 represents auxiliary units for adjusting a hydrogen concentration in a respective anode subsystem, and Reci represents auxiliary units for adjusting an anode recirculation rate.
Claims
Claims 1. An operating method (100) for operating a fuel cell system (200), wherein the fuel cell system (200) comprises a plurality of partial fuel cell systems (201, 207) and a number of system assemblies, each of which is configured to jointly operate all of the partial fuel cell systems (201, 207) of the plurality of partial fuel cell systems (201, 207), each partial fuel cell system (201, 207) comprising a number of subassemblies, each of which is configured to specifically operate only one respective partial fuel cell system (201, 207), the operating method (100) comprising: Operating (101) the plurality of partial fuel cell systems (201, 207) in a symmetrical operating mode, in which each partial fuel cell system (201, 207) is operated at a centrally predetermined system operating point, and / or Operating (103) the plurality of partial fuel cell systems (201, 207) in an asymmetric operating mode in which each partial fuel cell system (201, 207) is operated at an individual operating point.
2. Operating method (100) according to claim 1, characterized in that the subassemblies are used to adjust a mass flow of at least one operating medium through an anode subsystem of a respective partial fuel cell system (201, 207), wherein the subassemblies of each partial fuel cell system (201, 207) comprise at least one assembly from the following list of subassemblies: Anode recirculation blower, jet pump, anode control valve, anode recirculation valve.
3. Operating method (100) according to claim 1 or 2, characterized in that the subassemblies are used to adjust a water discharge from a respective partial fuel cell system (201, 207), wherein the subassemblies of each partial fuel cell system (201, 207) comprise at least one assembly from the following list of subassemblies: Water drain valve, water separator.
4. Operating method (100) according to one of the preceding claims, characterized in that the subassemblies are used to set a specific hydrogen concentration in a respective sub-fuel cell system (201, 207), wherein the subassemblies of each sub-fuel cell system (201, 207) comprise at least one assembly from the following list of subassemblies: Hydrogen metering valve, anode control valve at the anode inlet, anode control valve at the anode outlet.
5. Operating method (100) according to one of the preceding claims, characterized in that the system modules are used to jointly adjust a mass flow of at least one operating medium through all partial fuel cell systems (201, 207), wherein the system modules comprise at least one central module from the following list of central modules: anode recirculation blower, jet pump, water separator, hydrogen metering valve in a bypass line, 6. Operating method (100) according to claim 5, characterized in that that switching between the asymmetric operating mode and the symmetric operating mode occurs depending on a provided power requirement or a system state.
7. A fuel cell system (200) for converting energy, the fuel cell system (200) comprising: a plurality of partial fuel cell systems (201, 207), each partial fuel cell system (201, 207) comprising a number of sub-assemblies, each configured to specifically operate only a respective partial fuel cell system (201, 207), a number of system assemblies, each configured to jointly operate all partial fuel cell systems (201, 207) of the plurality of partial fuel cell systems (201, 207), a computing unit, the computing unit being configured to carry out an operating method (100) according to any one of claims 1 to 6.
8. Fuel cell system (200) according to claim 7, characterized in that the computing unit is configured to operate the plurality of partial fuel cell systems (201, 207) in a symmetrical operating mode and to operate each partial fuel cell system (201, 207) at a centrally predetermined system operating point, and / or to operate the plurality of partial fuel cell systems (201, 207) in an asymmetrical operating mode and to operate each partial fuel cell system at an individual operating point.
9. Fuel cell system (200) according to claim 7 or 8, characterized in that the fuel cell system (200) comprises as subassemblies of each partial fuel cell system (201, 207) at least one assembly from the following list of subassemblies: Anode recirculation blower, jet pump, anode control valve, anode recirculation valve, water drain valve, water separator, hydrogen dosing valve, anode control valve at the anode inlet, anode control valve at the anode outlet.
10. Fuel cell system (200) according to one of claims 7 to 9, characterized in that the fuel cell system (200) comprises as system modules at least one central module from the following list of central modules: Anode recirculation blower, jet pump, water separator, hydrogen dosing valve in a bypass line.