Fuel cell cluster

Abstract

The invention relates to a fuel cell cluster, in particular a SOFC cluster, for supplying power to an infrastructure (12a; 12b; 12c; 12d), in particular a critical infrastructure, with several fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d), in particular several SOFC fuel cell units, with an electrical supply module (22a; 22b; 22c; 22d) for supplying the infrastructure to be supplied (12a; 12b; 12c; 12d) with electrical energy from the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d), wherein the electrical supply module (22a; 22b; 22c; 22d) provides an electrical supply path (24a; 24b; 24c; 24d) has, via which electrical energy can be supplied to all fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) of the infrastructure to be supplied (12a; 12b; 12c; 12d). It is proposed that the supply module (22a; 22b; 22c; 22d) has a second electrical supply path (26a; 26b; 26c; 26d) via which electrical energy from all fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) of the infrastructure to be supplied (12a; 12b; 12c; 12d) can be supplied as an alternative to the first supply path (24a; 24b; 24c; 24d).

Description

State of the art

[0001] A fuel cell cluster, in particular a SOFC cluster, for supplying power to an infrastructure, in particular a critical infrastructure, has already been proposed, comprising several fuel cell units, in particular several SOFC fuel cell units, with an electrical supply module for supplying the infrastructure to be supplied with electrical energy from the fuel cell units, wherein the electrical supply module has an electrical path through which electrical energy from all fuel cell units can be supplied to the infrastructure to be supplied. Disclosure of the invention

[0002] The invention relates to a fuel cell cluster, in particular a SOFC cluster, for supplying power to an infrastructure, in particular a critical infrastructure, with several fuel cell units, in particular several SOFC fuel cell units, with an electrical supply module for supplying the infrastructure to be supplied with electrical energy from the fuel cell units, wherein the electrical supply module has an electrical supply path via which electrical energy from all fuel cell units can be supplied to the infrastructure to be supplied.

[0003] It is proposed that the supply module has a second electrical supply path, via which electrical energy can be supplied to all fuel cell units of the infrastructure to be supplied as an alternative to the first supply path.

[0004] The term "fuel cell cluster" preferably refers to a fuel cell system consisting of several fuel cell units. Preferably, the fuel cell cluster comprises a plurality of fuel cell units, in particular at least five, preferably more than ten, and most preferably more than 15. The fuel cell units are preferably of identical construction. Alternatively, the fuel cell cluster comprises at least two differently configured fuel cell units, for example, with different nominal power outputs or with different fuel cell types. Unless otherwise specified, "power output" is always understood to mean electrical power output. The terms "first fuel cell unit" and "further fuel cell unit" preferably serve only for linguistic differentiation.In particular, each of the multiple fuel cell units can be used as the first fuel cell unit or as a further fuel cell unit. The fuel cell units are preferably operable independently of one another, in particular being able to be switched on or off independently and / or modulated independently. Particularly preferred are the fuel cell units being structurally separate units, which are preferably spaced apart from one another and which can be replaced individually or in groups. One, and in particular each, of the fuel cell units has, for example, a nominal power output of more than 1 kW, preferably more than 10 kW, and particularly preferably at least 20 kW. One, and in particular each, of the fuel cell units has, for example, a nominal power output of less than 100 kW, preferably less than 50 kW, and particularly preferably less than 25 kW.The fuel cell cluster is preferably designed as a self-contained system for the, in particular, decentralized generation of electrical energy. The fuel cell cluster is preferably intended for the electrical supply of an infrastructure. In principle, it would also be conceivable for the fuel cell cluster to additionally provide heat to an infrastructure. The fuel cell cluster preferably has a nominal output of at least 25 kW, more preferably at least 50 kW, and particularly advantageously at least 100 kW. In principle, it would also be conceivable for the fuel cell cluster to have a nominal output greater than 200 kW or greater than 500 kW. The inventive concept is particularly independent of the exact nominal output of the fuel cell cluster. Preferably, several fuel cell clusters can also be operated together in a decentralized energy supply system and scaled up to the megawatt range.For example, a fuel cell cluster can be designed as a plug-and-play system, which is arranged in a housing, such as a container, and only needs to be connected to a fuel gas supply and the corresponding infrastructure to be supplied at its place of use.

[0005] A "fuel cell unit" is preferably understood to be a unit comprising at least one fuel cell, more preferably at least one stack of fuel cells or a group of several stacks of fuel cells, as well as peripheral devices specifically designed for the operation of the at least one fuel cell. A fuel cell is understood to be, in particular, a single cell consisting of an anode, an electrolyte, and a cathode. Several of these fuel cells, configured as single cells, are electrically connected in series to form a stack. Several fuel cells configured as single cells, connected in series to form a stack, constitute the fuel cell unit, configured as a fuel cell stack. The at least one fuel cell is particularly preferably a high-temperature fuel cell, more preferably a solid oxide fuel cell (SOFC) or a molten carbonate fuel cell.A "SOFC fuel cell unit" is understood to be a solid oxide fuel cell. Alternatively, the at least one fuel cell may be designed as a polymer electrolyte fuel cell, a phosphorus fuel cell, or a fuel cell of another type. Preferably, the fuel cells of the fuel cell unit, i.e., the electrodes of the individual cells themselves, consisting of anode, electrolyte, and cathode, are electrically connected in series and, in particular, can only be operated together. Examples of peripheral devices of one, and especially each, of the fuel cell units include a separate reformer, a separate exhaust gas recirculation system, at least one separate exhaust gas heat exchanger, a separate air intake, a separate fuel delivery unit, a separate afterburner, and / or the like. The peripheral devices include, in particular, electrically operated elements such as electric motors, actuators, sensors, valves, electric heating elements, and / or the like.Preferably, one, and in particular each, of the fuel cell units comprises a unit housing in which the at least one fuel cell, i.e., in particular the individual cells connected in series to form a stack, and the associated peripheral devices are arranged together. Each fuel cell unit, which is configured as a stack of several fuel cells configured as individual cells, has its own unit housing. An "infrastructure" is preferably understood to mean an infrastructure with electrical loads that are supplied with electricity by means of the fuel cell cluster. In principle, it would be conceivable that the infrastructure to be supplied is a building or a facility that has loads that can be electrically operated. For example, it would be conceivable that the infrastructure is configured as a residential complex or an industrial facility, such as a factory or a production plant.The term "critical infrastructure" is preferably understood to mean infrastructure that requires a reliable power supply and is essential for maintaining vital facilities or services. Specifically, critical infrastructure includes facilities or systems for which an operator must provide a fail-safe power supply, such as systems that power essential medical equipment, emergency power supplies, emergency lighting, or a data center. In particular, "critical infrastructure" refers to infrastructure that must be protected and secured against power outages. A data center, such as an edge data center, is preferably considered critical infrastructure. Fundamentally, critical infrastructure can also include a hospital or other facility that requires protection against power outages.The term "electrical supply module" preferably refers to the electrical component of the fuel cell cluster, which is designed to convert, distribute, and transmit the electrical energy generated by the fuel cell units to the infrastructure being supplied. The electrical supply module is also intended to supply the fuel cell units, and in particular their peripheral devices, with electrical current.

[0006] An "electrical supply path" is preferably understood to be an electrical connection path with conductors and / or electrical or electronic components, designed for the conversion, distribution, and transmission of electrical energy from the fuel cell units to consumers within the infrastructure being supplied. The electrical supply path preferably also includes components for voltage conversion. A "secondary electrical supply path" is understood to be an additional supply path for electrical energy, completely separate from the primary electrical supply path. The second electrical supply path provides an alternative electrical connection path for all fuel cell units to the consumers within the infrastructure being supplied.The phrase "the electrical energy can be supplied as an alternative to the first supply path" means that the electrical energy of all fuel cell units can be supplied to the infrastructure via one supply path if the other supply path fails. The electrical energy generated by the fuel cell units can be supplied to the infrastructure via either one electrical supply path or, alternatively, via the second electrical supply path. In any given operating state, some of the fuel cell units can be connected to the first electrical supply path and others to the second.

[0007] The design of the fuel cell cluster according to the invention allows it to be implemented particularly simply and cost-effectively as a fail-safe module, which is especially well protected against failure in order to ensure a reliable power supply for the infrastructure to be served. According to the invention, a defect in one of the electrical supply paths can be compensated for simply and quickly by enabling all fuel cell units to supply the infrastructure to be served with electrical energy via the other, undamaged electrical supply path.

[0008] It is further proposed that the supply module for each fuel cell unit includes a switching module by means of which the respective fuel cell unit can be electrically coupled either to a supply line of the first supply path or to a supply line of the second supply path. A "switching module" is preferably understood to be a module that can be switched between at least a first switching position and a second switching position, wherein the switching module has different switching positions, the respective fuel cell unit being electrically coupled to the first supply path in the first switching position and electrically coupled to the second supply path in the second switching position.In principle, it is conceivable that the switching module has a neutral position in which it is open and the respective fuel cell unit is not electrically coupled to either of the two supply paths. The switching module is preferably formed by two separately switchable switching elements, each of which can electrically connect or disconnect a fuel cell unit from one of the supply paths. It is also conceivable that the switching module is formed by a single switching element that selectively connects either one or the other supply path electrically to the respective fuel cell unit. Preferably, the switching module is formed by a circuit breaker. A "circuit breaker" is preferably understood to be a switch designed for switching high currents.A circuit breaker can preferably not only switch regular operating currents and small overload currents, but also, in the event of a fault, switch on high overload currents, hold these currents for a predetermined time, and safely switch them off without damage. A "supply line" is preferably understood to be an electrical line to which the fuel cell units are directly connected. The fuel cell units can be selectively connected directly to one of the supply lines via the switching modules. A supply line is designed as an electrical line to which the fuel cell units can be connected directly and in parallel to each other. Preferably, the fuel cell units output a DC voltage. The supply lines of the supply paths are preferably designed as DC supply lines.In principle, it would also be conceivable for the fuel cell units to output an alternating current (AC) voltage. In that case, the supply lines would be designed as AC power supply lines. This would allow each individual fuel cell unit to be connected to its respective supply path independently. This would make switching to the other supply path particularly easy and quick in the event of a fault in one of the supply paths.

[0009] Furthermore, it is proposed that each electrical supply path include an auxiliary power supply path for supplying the fuel cell units with alternating current, which is connected to a supply line of the respective supply path via a DC / AC converter. An "auxiliary power supply path" is preferably understood to be an electrical supply path for supplying the peripheral devices of the fuel cell units or for operating the fuel cell units. Since the peripheral devices of the fuel cell units are operated using alternating current, the auxiliary power supply path is designed as an AC power supply path. A "DC / AC converter" is understood to be an inverter that converts a direct current voltage into an alternating current voltage. "Connected" is preferably understood to mean electrically connected.This allows for advantageous and simple redundancy in the electrical supply of the fuel cell units, making it easy to compensate for a failure in one of the auxiliary power supply paths.

[0010] It is further proposed that each supply path include an energy storage device designed to be charged during normal operation and to support the infrastructure's power supply during operation with increased and / or dynamically fluctuating electricity demand. An "energy storage device" is preferably understood to be an electrical energy storage device for storing electrical energy. The energy storage device is designed to be charged in at least one operating state, particularly by the fuel cell units. In another operating state, the energy storage device is designed to release electrical energy, particularly to supply the infrastructure to be supplied with electricity. An energy storage device is specifically designed as a battery.The energy storage systems are preferably designed to supply electrical power in an operating state where the fuel cell units cannot provide the required power demanded by the infrastructure, in order to compensate for the difference between the available and requested electrical power. The energy storage systems are preferably designed to compensate for fluctuations in the electrical energy supplied by the fuel cell units or fluctuations in the load demand of the infrastructure, i.e., the electrical energy requested by the infrastructure. A "normal operating state" is preferably understood to mean an operating state in which all components of the fuel cell cluster operate normally, in particular without malfunctions or errors.In normal operating conditions, preferably half of the fuel cell units of the fuel cell cluster are connected to the infrastructure to be supplied, in particular to the consumers of the infrastructure, via one supply path and the other half via the other supply path. This allows the fuel cell cluster to advantageously compensate for fluctuations in the energy supply to the infrastructure. In particular, rapid changes in load requirements or a drop in output or failure of a fuel cell unit can be quickly compensated for. Advantageously, the energy storage system can bridge periods required by the fuel cell units to increase their output power.

[0011] Furthermore, it is proposed that the energy storage devices of the supply paths are each connected to a supply line of the respective supply path via a DC / DC converter. A "DC / DC converter" is preferably understood to be a converter that converts an input DC voltage into a stable output DC voltage and can boost or attenuate it. This allows the energy storage device to be integrated into the respective supply path particularly easily.

[0012] Furthermore, it is proposed that each supply path include a DC / AC converter. This allows the DC voltage provided by the fuel cell units to be converted into an AC voltage required for operating the infrastructure in each supply path, thus advantageously compensating for the failure of one of the two DC / AC converters.

[0013] Furthermore, it is proposed that each supply path include a transformer. This allows the alternating voltage flowing within each supply path to be advantageously transformed to a voltage required by the infrastructure, thus effectively compensating for the failure of either transformer.

[0014] It is further proposed that each supply path include a consumer power supply line to which consumers of the infrastructure being supplied are connected. A "consumer power supply line" is preferably understood to be an electrical line to which the infrastructure being supplied, and in particular the consumers of the infrastructure being supplied, can be connected for power supply. This allows the infrastructure being supplied to be conveniently and easily connected to both supply paths.

[0015] Furthermore, it is proposed that each supply path include at least one disconnect switch, allowing the electrical connection between a supply line and a consumer power supply line of the respective supply path to be severed. A "disconnect switch" is preferably understood to be an electrical switch that can open or close an electrical connection. The disconnect switch has a closed state, in which an electrical flow can occur between an input and an output, and an open state, in which an electrical flow between an input and an output cannot occur. This allows the supply paths to be advantageously and easily decoupled from the infrastructure they serve if a fault occurs in the respective supply path.

[0016] It is further proposed that the fuel cell cluster include a control unit for controlling the fuel cell units and the components of the supply paths. A "control unit" is understood to be, in particular, a unit with at least one control electronics module. Specifically, "control electronics" is understood to be a unit with a processor module, a memory module, and an operating program stored in the memory module. The control unit is intended to execute a procedure for controlling the fuel cell cluster.The control unit preferably sends control signals to peripheral devices and / or other components of the fuel cell cluster for its operation, such as, in particular, a central fuel supply, a central air supply, a central power supply, or the like. The control unit is preferably configured to selectively control the fuel cell units. The control unit is designed to control the supply module, especially its components. The control unit is preferably also configured to control the disconnect switches of the entire supply path. This allows for particularly advantageous control of the fuel cell cluster.

[0017] Furthermore, a method for operating a fuel cell cluster with multiple fuel cell units and a supply module having two supply paths is proposed, wherein in one process step the fuel cell units can be electrically coupled to either the first or the second supply path. This allows a fuel cell cluster to be operated particularly advantageously as a fail-safe fuel cell cluster, and the failure of components of the supply module can be compensated for.

[0018] It is further proposed that, in an operating condition where a fault occurs in one of the two supply paths, the fuel cell units supplying the infrastructure should be electrically connected to the other supply path. This would make fail-safe operation particularly easy to achieve.

[0019] The fuel cell cluster according to the invention is not to be limited to the application and embodiment described above. In particular, the fuel cell cluster according to the invention may, to fulfill a functionality described herein, have a different number of individual elements, components, units, and process steps than specified herein. Furthermore, values ​​within the specified limits of the value ranges stated in this disclosure shall also be considered disclosed and freely usable. drawing

[0020] Further advantages will become apparent from the following description of the drawings. The drawings illustrate four exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination. It will be advantageous for those skilled in the art to also consider the features individually and combine them into meaningful further combinations.

[0021] They show: Fig. 1 a schematic representation of a fuel cell cluster according to the invention in a first embodiment, Fig. 2 a schematic representation of a fuel cell cluster according to the invention in a second embodiment, Fig. 3 a schematic representation of a fuel cell cluster according to the invention in a third embodiment and Fig. 4 a schematic representation of a fuel cell cluster according to the invention in a fourth embodiment. Description of the embodiments

[0022] The Fig. Figure 1 shows a fuel cell cluster 10a according to the invention in a first embodiment. The fuel cell cluster 10a is intended for supplying an infrastructure 12a, in particular a critical infrastructure 12a. The infrastructure 12a is, for example, configured as a data center. The data center is, for example, configured as an edge data center. The infrastructure 12a has several consumers 14a, 16a. In the present embodiment, the consumers 14a, 16a are configured as servers of the infrastructure 12a configured as a data center. By way of example, the infrastructure 12a to be supplied has twelve consumers 14a, 16a, whereby, for the sake of clarity, only two consumers 14a, 16a have been designated with a reference numeral. The consumers 14a, 16a can be configured identically. However, it is fundamentally irrelevant for the embodiment according to the invention whether the consumers 14a, 16a are configured identically.In principle, it would also be conceivable that the infrastructure to be supplied (12a) has a different number of consumers (14a, 16a), or even a different number of consumers (14a, 16a). It would also be conceivable that the infrastructure to be supplied (12a) has only one consumer (14a, 16a).

[0023] The fuel cell cluster 10a is designed as a fail-safe fuel cell cluster. The fuel cell cluster 10a is designed to reliably supply the infrastructure 12a. The fuel cell cluster 10a is designed to compensate for the failure of individual components. The fuel cell cluster 10a has a nominal power output. For this embodiment, the nominal power output of the fuel cell cluster 10a is 100 kW. In principle, it would also be conceivable for the fuel cell cluster 10a to have a different nominal power output, for example, 50 kW, 200 kW, or more than 500 kW. The exact nominal power output of the fuel cell cluster 10a is irrelevant for the invention. The fuel cell cluster 10a is designed to reliably supply the infrastructure 12a by providing at least the essential, and preferably the entire, nominal power output.To ensure a reliable supply of electrical energy to the infrastructure 12a to be supplied, the fuel cell cluster 10a should always provide at least 90%, preferably 95% and particularly preferably more than 99% of the nominal power.

[0024] The fuel cell cluster 10a is configured as a solid oxide fuel cell (SOFC) cluster. The fuel cell cluster 10a comprises several fuel cell units 18a, 20a. The fuel cell units 18a, 20a are configured as SOFC fuel cell units. The fuel cell units 18a, 20a are configured as fuel cell stacks. Preferably, the fuel cell units 18a, 20a are configured as solid oxide fuel cell stacks. The fuel cell units 18a, 20a each comprise several fuel cells, in particular solid oxide fuel cells. The fuel cell units 18a, 20a each have peripheral devices for operating the fuel cells of the fuel cell units 18a, 20a. The peripheral devices are not described in detail here and are known from the prior art. The fuel cell units 18a, 20a are preferably configured as hot boxes. The fuel cell units 18a, 20a preferably each have their own independent housing.The fuel cell units 18a and 20a each have a nominal power output. The sum of the nominal power outputs of the fuel cell units 18a and 20a is at least as high as the nominal power output of the fuel cell cluster 10a. The nominal power output of the fuel cell cluster 10a can be at most equal to the sum of the nominal power outputs of the fuel cell units 18a and 20a. Preferably, the sum of the nominal power outputs of the fuel cell units 18a and 20a is greater than the nominal power output of the fuel cell cluster 10a. Preferably, the sum of the nominal power outputs of all fuel cell units 18a and 20a is at least 5%, preferably at least 10%, and most preferably 20% greater than the nominal power output of the fuel cell cluster 10a.

[0025] Fuel cell cluster 10a comprises, for example, twelve fuel cell units 18a, 20a. The twelve fuel cell units 18a, 20a preferably each have a nominal power output of 10 kW. The sum of the nominal power outputs of the fuel cell units 18a, 20a is thus 120 kW, which is 20% higher than the nominal power output of the fuel cell cluster 10a. By using twelve fuel cell units 18a, 20a with a combined nominal power output of 120 kW, two fuel cell units 18a, 20a can fail in this embodiment, and the fuel cell cluster 10a can provide its nominal power output during normal operation of the remaining ten fuel cell units 18a, 20a. The fuel cell units 18a, 20a are identical. In principle, it would also be conceivable that not all fuel cell units 18a, 20a are identical. The fuel cell units 18a and 20a each have the same nominal power output.In principle, it would also be conceivable here that fuel cell units 18a and 20a of fuel cell cluster 10a have at least partially different nominal power outputs. For the sake of clarity, only two of the twelve fuel cell units 18a and 20a are marked with a reference symbol in the figures.

[0026] The fuel cell cluster 10a includes an electrical supply module 22a. The electrical supply module 22a is designed to supply the infrastructure 12a with the electrical energy generated by the fuel cell units 18a and 20a. The electrical supply module 22a allows the consumers 14a and 16a of the infrastructure 12a to be electrically connected to the fuel cell units 18a and 20a. During operation, electrical current generated by the fuel cell units 18a and 20a of the fuel cell cluster 10a flows via the electrical supply module 22a to the infrastructure 12a, specifically to its consumers 18a and 20a.

[0027] The supply module 22a has a first electrical supply path 24a. Electrical energy from all fuel cell units 18a, 20a of the fuel cell cluster 10a can be supplied to the infrastructure 12a via the first electrical supply path 24a. Preferably, each fuel cell unit 18a, 20a of the fuel cell cluster 10a can be electrically connected to the infrastructure 12a, i.e., to its consumers 14a, 16a, via the first electrical supply path 24a.

[0028] The supply module 22a has a second electrical supply path 26a. Electrical energy from all fuel cell units 18a, 20a of the fuel cell cluster 10a can be supplied to the infrastructure 12a via this second electrical supply path 26a. Preferably, each fuel cell unit 18a, 20a of the fuel cell cluster 10a can be electrically connected to the infrastructure 12a, i.e., to its consumers 14a, 16a, via this second electrical supply path 26a. Alternatively to the first supply path 24a, electrical energy from all fuel cell units 18a, 20a of the fuel cell cluster 10a can be supplied to the infrastructure 12a via this second electrical supply path 26a of the supply module 22a.The infrastructure 12a to be supplied, in particular all consumers 14a, 16a thereof, can be connected to the fuel cell units 18a, 20a of the fuel cell cluster 10a via the second supply path 26a as an alternative to the first supply path 24a. The fuel cell units 18a, 20a of the fuel cell cluster 10a can be electrically connected either to the first electrical supply path 24a or to the second electrical supply path 26a. The fuel cell units 18a, 20a of the fuel cell cluster 10a can each be individually electrically connected either to the first electrical supply path 24a or to the second electrical supply path 26a.

[0029] Preferably, all fuel cell units 18a, 20a of the fuel cell cluster 10a can be simultaneously connected to the first supply path 24a during operation. The infrastructure 12a to be supplied would then be provided exclusively via the first electrical supply path 24a with the electrical energy generated by the fuel cell units 18a, 20a. Preferably, all fuel cell units 18a, 20a of the fuel cell cluster 10a can also be simultaneously connected to the second supply path 26a during operation. The infrastructure 12a to be supplied would then be provided exclusively via the second electrical supply path 26a with the electrical energy generated by the fuel cell units 18a, 20a.Preferably, in an operation, some of the fuel cell units 18a, 20a can be electrically connected to the first electrical supply path 24a and another part of the fuel cell units 18a, 20a to the second electrical supply path 26a. This would allow part of the infrastructure 12a to be supplied, i.e., preferably part of the consumers 14a, 16a of the infrastructure 12a, to be supplied via the first electrical supply path 24a with the electrical energy generated by part of the fuel cell units 18a, 20a, and part of the infrastructure, in particular a second part of the consumers 14a, 16a of the infrastructure 12a to be supplied, to be supplied via the second electrical supply path 26a with the electrical energy generated by the other part of the fuel cell units 18a, 20a.Advantageously, in such an operating condition, one half of the fuel cell units 18a, 20a of the fuel cell cluster 10a are electrically connected to the first electrical supply path 24a and the other half of the fuel cell units 18a, 20a are electrically connected to the second electrical supply path 26a.

[0030] The supply module 22a has one switching module 28a, 30a for each fuel cell unit 18a, 20a of the fuel cell cluster 10a. In the illustrated embodiment with twelve fuel cell units 18a, 20a, the supply module 22a accordingly has twelve switching modules 28a, 30a. For clarity, only two of the switching modules 28a, 30a are labeled with a reference numeral in the figures. For clarification, the two switching modules 28a, 30a that are located on the referenced fuel cell units 18a, 20a are labeled with reference numerals. The switching modules 28a, 30a are each arranged directly between one of the fuel cell units 18a, 20a and the two supply paths 24a, 26a of the supply module 22a. Each switching module 28a, 30a is assigned to exactly one fuel cell unit 18a, 20a of the fuel cell cluster 10a.The respective fuel cell unit 18a, 20a can be electrically connected to either the first electrical supply path 24a or the second supply path 26a via the corresponding switching module 28a, 30a. Preferably, in a neutral position, the switching modules 28a, 30a cannot electrically couple the associated fuel cell unit 18a, 20a to either of the two electrical supply paths 24a, 26a. In the neutral position of a switching module 28a, 30a, the associated fuel cell unit 18a, 20a is electrically disconnected from the supply module 22a, and in particular from both supply paths 24a, 26a. The switching modules 28a, 30a are preferably designed as circuit breakers.

[0031] The two supply paths 24a, 26a of the supply module 22a are preferably identical. Due to the identical design of both supply paths 24a, 26a of the supply module 22a, the infrastructure 12a to be supplied with electrical energy from the fuel cell units 18a, 20a can be supplied in the same way via both supply paths 24a, 26a. Because of the identical design of both supply paths 24a, 26a of the supply module 22a, it is irrelevant whether the infrastructure 12a to be supplied is powered via the first supply path 24a or the second supply path 26a. The two supply paths 24a, 26a of the supply module 22a preferably each have the same components. The two supply paths 24a, 26a of the supply module 22a have the same structure, in particular the same interconnection of their components.

[0032] Electrical supply paths 24a and 26a each have a supply line 32a and 34a, respectively. Supply lines 32a and 34a are intended for connecting the fuel cell units 18a and 20a to their respective supply paths 24a and 26a. The first supply path, 24a, has supply line 32a. The second supply path, 26a, has supply line 34a. Supply lines 32a and 34a of supply paths 24a and 26a can be directly connected to the corresponding fuel cell units 18a and 20a via switching modules 28a and 30a. The fuel cell units 18a and 20a are connected in parallel to supply lines 32a and 34a of supply paths 24a and 26a via switching modules 28a and 30a.Via the switching modules 28a, 30a, electrical energy can be directed from the corresponding fuel cell units 18a, 20a directly into the supply line 32a of the first supply path 24a or into the supply line 34a of the second supply path 26a.

[0033] The electrical supply paths 24a and 26a each have an auxiliary power supply path 36a and 38a, respectively. The auxiliary power supply paths 36a and 38a are intended to supply the fuel cell units 18a and 20a with alternating current. The auxiliary power supply paths 36a and 38a are intended to supply the peripheral devices of the fuel cell units 18a and 20a with electrical energy for the operation of the fuel cell units 18a and 20a. The fuel cell units 18a and 20a each have a peripheral device circuit, which is not shown in detail. The peripheral devices of the respective fuel cell units 18a and 20a can be supplied with electrical energy via this peripheral device circuit.The supply module 22a has one switching module 40a, 42a for each fuel cell unit 18a, 20a of the fuel cell cluster 10a, via which the peripheral device circuits of the fuel cell units 18a, 20a can each be electrically connected to the auxiliary power supply paths 36a, 38a of the supply paths 24a, 26a. In the illustrated embodiment with twelve fuel cell units 18a, 20a, the supply module 22a has twelve switching modules 40a, 42a accordingly. For clarity, only two of the switching modules 40a, 42a are shown with a reference numeral in the figures. For clarification, the two switching modules 40a, 42a that are located on the fuel cell units 18a, 20a with reference numerals are shown.The switching modules 40a, 42a are each arranged directly between the peripheral device circuits of the respective fuel cell units 18a, 20a and the two auxiliary power supply paths 36a, 38a of the supply paths 24a, 26a of the supply module 22a. Each switching module 40a, 42a is assigned to exactly one fuel cell unit 18a, 20a, in particular to one peripheral device circuit of one of the fuel cell units 18a, 20a of the fuel cell cluster 10a. Via the corresponding switching module 40a, 42a, the respective peripheral device circuit of one of the fuel cell units 18a, 20a can be electrically connected either to the auxiliary power supply path 36a of the first electrical supply path 24a or to the auxiliary power supply path 38a of the second supply path 26a.Preferably, the switching modules 40a, 42a, in a neutral position, cannot electrically couple the respective peripheral device circuit of the corresponding fuel cell unit 18a, 20a to either of the two auxiliary power supply paths 36a, 38a. In the neutral position of a switching module 40a, 42a, the associated fuel cell unit 18a, 20a is not supplied with an auxiliary current for operation and cannot be operated.

[0034] The peripheral devices of the fuel cell units 18a, 20a are preferably operated with alternating current. The electrical supply paths 24a, 26a each have a DC / AC converter 44a, 46a. The auxiliary power supply paths 36a, 38a of the supply paths 24a, 26a are connected via the DC / AC converters 44a, 46a to the supply lines 32a, 34a of the respective supply path 24a, 26a. The DC / AC converters 44a, 46a allow the direct current fed into the supply line 32a, 34a of the supply paths 24a, 26a by the fuel cell units 18a, 20a to be converted into an alternating current, which can be supplied to the peripheral device circuits of the fuel cell units 18a, 20a for their operation via the auxiliary power supply paths 36a, 38a.

[0035] The electrical supply paths 24a and 26a each have an energy storage device 48a and 50a, respectively. The energy storage devices 48a and 50a are designed as electrical energy storage devices. The energy storage devices 48a and 50a are preferably designed as batteries. The energy storage devices 48a and 50a are intended to be charged during normal operating conditions. During operating conditions with increased power demand, the energy storage devices 48a and 50a are intended to support the power supply of the infrastructure 12a. The energy storage devices 48a and 50a are preferably intended to feed electrical energy into the respective supply paths 24a and 26a, particularly when there is an increased load demand from the infrastructure 12a.The energy storage devices 48a, 50a are preferably designed to feed electrical energy into the corresponding supply path when the energy currently supplied by the respective fuel cell units 18a, 20a is less than the load demand of the infrastructure 12a to be supplied. The energy storage devices 48a, 50a are preferably designed to compensate for fluctuations in the load demand of the infrastructure 12a to be supplied. The energy storage devices 48a, 50a are preferably designed to compensate for fluctuations in the electrical energy supplied by the fuel cell units 18a, 20a.Firstly, in the event of a rapid increase in load demand from the infrastructure 12a being supplied, the energy storage units 48a, 50a can feed in a difference between the electrical energy requested by the infrastructure 12a and the electrical energy supplied by the fuel cell units 18a, 20a until the corresponding fuel cell units 18a, 20a have been sufficiently ramped up and are generating all the required electrical energy. This is necessary because the fuel cell units 18a, 20a have a certain response time before they can provide the required electrical energy. Likewise, the energy storage units 48a, 50a can temporarily compensate for the failure of one fuel cell unit 18a, 20a until the remaining fuel cell units 18a, 20a have been sufficiently ramped up to compensate for the failure of the single fuel cell unit 18a, 20a.The energy storage units 48a and 50a are advantageously designed to compensate for the failure of two fuel cell units 18a and 20a.

[0036] Supply paths 24a and 26a each have a DC / DC converter 52a and 54a, respectively. The respective energy storage devices 48a and 50a are connected to the supply lines 32a and 34a of the respective supply paths 24a and 28a via the DC / DC converters 52a and 54a. DC / DC converter 52a is assigned to the first supply path 24a. In the circuit, DC / DC converter 52a is located between energy storage device 48a and supply line 32a of the first electrical supply path 24a. DC / DC converter 54a is assigned to the second supply path 26a. In the circuit, DC / DC converter 54a is located between energy storage device 50a and supply line 34a of the second electrical supply path 26a.

[0037] Supply paths 24a and 26a each have a consumer power supply line 56a and 58a, respectively. Consumer power supply line 56a is part of the first electrical supply path 24a. Consumer power supply line 58a is part of the second electrical supply path 26a. The infrastructure 12a to be supplied can be electrically connected to the respective supply paths 24a and 26a via the consumer power supply lines 56a and 58a. Consumers 14a and 16a of the infrastructure 12a to be supplied are connected to the consumer power supply lines 56a and 58a. Preferably, each individual consumer 14a and 16a of the infrastructure 12a to be supplied can be electrically connected individually to the consumer power supply lines 56a and 58a of supply paths 24a and 26a. Each of the consumers 14a, 16a is preferably individually and independently of the other consumers 14a.16 of the infrastructure 12a can each be electrically coupled either to the consumer power supply line 56a of the first electrical supply path 24a or to the consumer power supply line 58a of the second electrical supply path 26a.

[0038] To couple the consumers 14a, 16a of the infrastructure 12a with the consumer power supply lines 56a, 58a of the supply paths 24a, 26a, the supply module has switching modules 60a, 62a.

[0039] The supply module 22a has one switching module 60a, 62a for each consumer 14a, 16a of the infrastructure 12a. For clarity, only two of the switching modules 60a, 62a are shown with a reference numeral in the figures. Specifically, the two switching modules 60a, 62a that are located at the consumers 14a, 16a of the infrastructure 12a that are marked with reference numerals are shown with reference numerals. The switching modules 60a, 62a are each located directly between one of the consumers 14a, 16a of the infrastructure 12a and the consumer power supply lines 56a, 58a of the two supply paths 24a, 26a of the supply module 22a. Each switching module 60a, 62a is assigned to exactly one consumer 14a, 16a of the infrastructure 12a.Via the corresponding switching module 60a, 62a, the respective consumer 14a, 16a of the infrastructure 12a can be electrically connected either to the first electrical supply path 24a or to the second supply path 26a, in particular to the corresponding consumer power supply lines 56a, 58a of a supply path 24a, 26a. Preferably, the switching modules 60a, 62a can electrically connect the respective consumer 14a, 16a simultaneously to the first electrical supply path 24a and to the second supply path 26a in one operating state. The consumers 14a, 16a can be electrically connected to both supply paths 24a, 26a simultaneously via the switching modules 60a, 62a. The power supplies of the corresponding consumers 14a, 16a are designed to be connected to both supply paths 24a, 26a simultaneously.Preferably, the switching modules 60a, 62a, in a neutral position, cannot electrically couple the corresponding consumer 14a, 16a of the infrastructure 12a to be supplied with either of the two electrical supply paths 24a, 26a. In the neutral position of the switching modules 60a, 62a, the corresponding consumer 14a, 16a of the infrastructure 12a is disconnected from the power supply by the fuel cell cluster 10a.

[0040] In principle, it would also be conceivable that the entire infrastructure 12a could only be connected in its entirety to one of the consumer power supply lines 56a, 58a of the supply paths 24a, 26a. For this purpose, the supply module 22a would only have a switching module that electrically couples the entire infrastructure 12a either to the first supply path 24a or the second supply path 26a.

[0041] Supply paths 24a and 26a each have a DC / AC converter 64a and 66a, respectively. DC / AC converter 64a is assigned to the first supply path 24a. DC / AC converter 66a is assigned to the second electrical supply path 26a. The DC / AC converters 64a and 66a are designed to convert the direct current (DC) voltage supplied by the fuel cell units 18a and 20a and / or the energy storage units 48a and 50a into alternating current (AC) voltage.

[0042] Supply paths 24a and 26a each have a transformer 68a and 70a, respectively. Transformer 68a is assigned to the first supply path 24a. Transformer 70a is assigned to the second electrical supply path 26a. Transformers 68a and 70a are designed to transform the alternating voltage supplied as DC voltage by the fuel cell units 18a and 20a and / or the energy storage units 48a and 50a, which is converted by the DC / AC converters 64a and 66a, in particular to increase the voltage and to enable, if necessary, an unbalanced load on the three-phase supply network. Transformer 68a and 70a can also be configured as a neutral conductor former. Transformers 68a and 70a are connected downstream of the DC / AC converters 44a and 46a of the respective supply paths 24a and 26a.

[0043] Supply paths 24a and 26a each have a first disconnect switch 72a and 74a, respectively. Disconnect switch 72a is assigned to the first supply path 24a. Disconnect switch 74a is assigned to the second supply path 26a. An electrical connection between a supply line 32a and 34a and a consumer power supply line 56a and 58a of the respective supply path 24a and 26a can be disconnected via the corresponding disconnect switch 72a and 74a. The first disconnect switch 72a and 74a is located in the respective supply line 32a and 34a and is connected upstream of the energy storage device 48a and 50a and the DC / AC converter 64a and 66a of the respective supply path 24a and 26a. The fuel cell units 18a, 20a of the fuel cell cluster 10a can be electrically disconnected from the remainder of the respective supply path 24a, 26a via the first disconnect switch 72a, 74a.

[0044] Supply paths 24a and 26a each have a second disconnect switch 76a and 78a, respectively. Disconnect switch 76a is assigned to the first supply path 24a. Disconnect switch 78a is assigned to the second supply path 26a. An electrical connection between a supply line 32a or 34a and a consumer power supply line 56a or 58a of the respective supply path 24a or 26a can be disconnected via the corresponding disconnect switch 76a or 78a. The second disconnect switch 76a or 78a is located between the DC-AC converters 64a and 66a and the transformers 68a and 70a of the respective supply path 24a or 26a. The fuel cell units 18a, 20a of the fuel cell cluster 10a and the energy storage units 48a, 50a can be electrically disconnected from a remainder of the respective supply path 24a, 26a facing the infrastructure 12a via the second disconnect switch 76a, 78a.The second disconnect switch 76a, 78a allows the consumer power supply lines 56a, 58a and the transformers 68a, 70a of the respective supply path 24a, 26a to be electrically disconnected from the remainder of the supply path 24a, 26a.

[0045] The fuel cell cluster 10a has a control unit 80a. Preferably, the fuel cell cluster 10a has at least one second control unit 100a. The second control unit 100a is provided as a fail-safe for the first control unit 80a. The second control unit 100a is designed to take over control of the fuel cell cluster 10a in the event of a failure of the first control unit 80a. For example, the second control unit 100a can only be activated if the first control unit 80a fails and then take over control of the fuel cell cluster 10a.Preferably, the two control units 80a, 100a can also control the fuel cell cluster 10a in parallel, wherein the control signals of the first control unit 80a have priority over those of the second control unit 100a, and the control signals of the second control unit 100a are only used to control the fuel cell cluster 10a if the first control unit 80a fails. In principle, it would also be conceivable that each control unit 80a, 100a could control a part of the fuel cell cluster 10a, for example, the components of a supply path 24a, 26a, and that if one of the two control units 80a, 100a fails, the remaining control unit 80a, 100a would take over the control tasks of the failed control unit 80a, 100a.The second control unit 100a is preferably identical in design and intended for the same tasks. Therefore, only the first control unit 80a will be described in detail below, whereby the description of the first control unit 80a can be used to explain the second control unit 100a. The control unit 80a is intended for controlling the fuel cell units 18a, 20a and the components of the supply paths 24a, 26a. The control or regulating unit 80a is preferably intended for controlling all switching modules 28a, 30a, 40a, 42a, 60a, 62a, all converters 44a, 46a, 52a, 54a, 64a, 66a, all transformers 68a, 70a and all disconnect switches 72a, 74a, 76a, 78a as well as the energy storage devices 48a, 50a.The control or regulation unit 80a is intended for controlling or regulating the fuel cell units 18a, 20a of the fuel cell cluster 10a and can adjust an output power of the fuel cell units 18a, 20a, preferably individually and independently of each other.

[0046] The following briefly describes a method for operating the fuel cell cluster 10a to reliably supply the power providers 14a and 16a of the infrastructure 12a. In a normal operating state, in which all fuel cell units 18a and 20a are fully functional and the other components of the fuel cell cluster 10a, in particular the power supply module 22a, are also functioning correctly, the infrastructure 12a is supplied with electrical energy by all fuel cell units 18a and 20a. In a process step during this normal operating state, the fuel cell units 18a and 20a can be electrically connected to either the first power supply path 24a or the second power supply path 26. During this normal operating state, the electrical energy is preferably routed to the infrastructure 12a via both power supply paths 24a and 26a.In normal operating conditions, preferably a portion of the consumers 14a, 16a of the infrastructure 12a to be supplied are supplied with electrical energy via the first supply path 24a from a first portion of the fuel cell units 18a, and another portion of the consumers 14a, 16a of the infrastructure 12a to be supplied are supplied with electrical energy via the second supply path 24a from another portion of the fuel cell units 20a. Preferably, in normal operating conditions, half of the fuel cell units 18a, 20a are electrically connected to the first supply path 24a and the other half of the fuel cell units 18a, 20a are electrically connected to the second supply path 24a. Preferably, in normal operating conditions, some of the consumers 14a, 16a of the infrastructure 12a to be supplied are electrically connected to the first supply path 24a and another portion to the second supply path.Preferably, in the normal operating state, exactly half of the consumers 16a, 18a of the infrastructure to be supplied are electrically connected to the first supply path 24a and the other half of the consumers 14a, 16a to the second supply path. In the normal operating state, the control unit 80a switches a portion, in particular half, of the fuel cell units 18a, 20a to the first supply path 24a via its switching modules 28a, 30a and a portion, in particular the other half, of the fuel cell units 18a, 20a to the second supply path 26a via the corresponding switching modules 28a, 30a. Examples are shown in the... Fig. 1 correspondingly six fuel cell units 18a are directly electrically connected via their switching module 28a to the supply line 32a of the first supply path 24a and the other six fuel cell units 20a are directly electrically connected via their switching module 30a to the supply line 34a of the second supply path 24a.

[0047] In principle, it would also be conceivable that in an alternative normal operating state, in which all fuel cell units 18a, 20a of the fuel cell cluster and all components of the supply module 20a, or all components of the fuel cell cluster 10a, are functioning, at least 80% or all fuel cell units 18a, 20a are electrically connected to a supply path, 24, 26, for example to the first supply path 24a.

[0048] During operation of the fuel cell cluster 10a, malfunctions or defects in individual components of the fuel cell cluster 10a may occur. If a fault or defect occurs in a component of a supply path 24a, 26a during operation, the fuel cell units 18a, 20a supplying the infrastructure 12a are all electrically connected to the infrastructure 12a via the other supply path 24a, 26a. If a fault occurs in a component of the first supply path 24a, all fuel cell units 18a, 20a currently electrically connected to the first supply path 24a are disconnected from the first supply path 24a and connected to the second supply path 26a.The control unit 80a activates the corresponding switching modules 40a and 42a to electrically disconnect the fuel cell units 18a and 20a from the supply line 32a of the first supply path 24a and connect them to the supply line 34a of the second supply path 26a. Essentially simultaneously, all fuel cell units 18a and 20a, in particular all peripheral circuits of the fuel cell units, are electrically connected to the auxiliary power supply path 28a of the second supply path 26a. In this process step, all switching modules 40a and 42a that were connected to the auxiliary power supply path 36a of the first supply path 24a are switched to the auxiliary power supply path 38a of the second supply path 26a. All consumers 14a, 16a of the infrastructure 12a to be supplied, which were connected to the primary supply path 24a in the normal operating state, will be switched to the second supply path 26a.The control or regulating unit 80a switches the corresponding switching modules 60a, 62a to the corresponding consumer power supply line 64a of the second supply path 26a.

[0049] Since, under normal operating conditions, preferably only half of all fuel cell units 18a, 20a were connected to the first supply path, it is advantageous that only these fuel cell units 18a, 20a need to be switched from the first supply path to the second supply path. This allows the infrastructure 12a to be supplied via the second supply path 26a by the fuel cell units 18a, 20a, which were already connected to the second supply path 26a under normal operating conditions, during the period between the occurrence of the defect in the first supply path 24a and the completion of the switchover to the second supply path 26a.During the period between the occurrence of the defect in the first supply path 24a and a completed switchover of the supply to the second supply path 26a, the energy storage unit 50a of the second supply path 26a feeds additional energy into the second supply path 26a to compensate for the missing electrical energy of the fuel cell units 18a, 20a which were connected to the first supply path 24a.

[0050] Depending on which component in the supply path 24a, 26a a fault occurs, the disconnect switches 72a, 74a can be opened to disconnect a defective part of the supply path 24a from the fuel cell units 18a, 20a or the infrastructure 12a to be supplied.

[0051] During normal operation, the fuel cell units 18a, 20a are preferably operated below their rated power. Should a fuel cell unit 18a, 20a fail during operation, the power loss can be compensated for by increasing the power output of the remaining fuel cell units. For this purpose, in an operating condition where a fuel cell unit 18a, 20a fails, the corresponding fuel cell unit is disconnected from both supply paths 24a, 26a via its switching module 28a, 30a. The power output of all other fuel cell units 18a, 20a is increased. Alternatively, if a fuel cell unit 18a, 20a fails that is connected to the first supply path 24a during normal operation, only the power output of all fuel cell units 18a, 20a connected to the first supply path is increased to compensate for the failure of the single fuel cell unit 18a, 20a.All other fuel cell units 18a, 20a connected to the second supply path 26a would continue operating without increasing their output power. While the fuel cell units 18a, 20a connected to the first supply path 24a increase their power output, the energy storage unit 48a feeds electrical energy into the first supply path 24a to compensate for the power loss of the failed fuel cell unit 18a, 20a until the remaining fuel cell units 18a, 20a have reached their full power output.

[0052] If a fault occurs only in one of the auxiliary power supply paths 36a, 38a, the supply to the fuel cell units 18a, 20a, in particular their peripheral circuits, only needs to be switched to the auxiliary power supply path 36a, 38a of the other supply path 24a, 26a. If a fault occurs in the second supply path 26a, an equivalent switch to the first supply path 24a is carried out, as described above for the reverse case.

[0053] In the Fig. Figures 2 to 4 show three further embodiments of the invention. The following descriptions and drawings are essentially limited to the differences between the embodiments, whereby, with regard to identically designated components, particularly those with the same reference numerals, reference is also generally made to the drawings and / or descriptions of the other embodiments, especially those of the Fig. 1, can be referenced. To distinguish the embodiments, the letter a is the reference numeral of the embodiment in the Fig. 1. In the exemplary embodiments of the Fig. In numbers 2 to 4, the letter a is replaced by the letters b to d.

[0054] The Fig. Figure 2 shows a fuel cell cluster 10b according to the invention in a second embodiment. The fuel cell cluster 10b is intended for supplying an infrastructure 12b, in particular a critical infrastructure 12b.

[0055] The infrastructure includes several consumers 14b, 16b. The fuel cell cluster 10b is designed as a fail-safe fuel cell cluster. The fuel cell cluster 10b is designed to reliably supply the infrastructure 12b. The fuel cell cluster 10b includes several fuel cell units 18b, 20b. The fuel cell units 18b, 20b are designed as SOFC fuel cell units. The fuel cell units 18b, 20b can be configured identically to those in the first embodiment.

[0056] Fuel cell cluster 10b includes an electrical supply module 22b. The electrical supply module 22b is designed to supply the infrastructure 12b with electrical energy generated by the fuel cell units 18b and 20b. Supply module 22b has a first electrical supply path 24b. Electrical energy from all fuel cell units 18b and 20b of fuel cell cluster 10b can be supplied to the infrastructure 12b via the first electrical supply path 24b. Supply module 22b also has a second electrical supply path 26b. Electrical energy from all fuel cell units 18b and 20b of fuel cell cluster 10b can be supplied to the infrastructure 12b via the second electrical supply path 26b.Via the second supply path 26b of the supply module 22b, electrical energy from all fuel cell units 18b, 20b of the fuel cell cluster 10b can be supplied to the infrastructure 12b to be supplied as an alternative to the first supply path 24b.

[0057] The supply module 22b has a switching module 28b, 30b for each fuel cell unit 18b, 20b of the fuel cell cluster 10b. The respective fuel cell unit 18b, 20b can be electrically connected to either the first electrical supply path 24b or the second supply path 26b via the corresponding switching module 28b, 30b. The electrical supply paths 24b, 26b each have a supply line 32b, 34b.

[0058] Electrical supply paths 24b and 26b each have a DC / AC converter 44b and 46b, respectively. Electrical supply paths 24b and 26b each have an energy storage device 48b and 50b, respectively. Supply paths 24b and 26b each have a DC / DC converter 52b and 54b, respectively. The supply module 22b has a switching module 60b and 62b for each consumer 14b and 16b of the infrastructure 12b. Supply paths 24b and 26b each have a DC / AC converter 64b and 66b, respectively. Supply paths 24b and 26b each have a transformer 68b and 70b, respectively. Transformer 68b is assigned to the first supply path 24b. Supply paths 24b and 26b each have a first disconnect switch 72b and 74b, respectively. Supply paths 24b and 26b each have a second disconnect switch 76b and 78b, respectively. The fuel cell cluster 10b has a control unit 80b.The control unit 80b is intended for controlling the fuel cell units 18b, 20b and the components of the supply paths 24b, 26b. The fuel cell cluster 10b has a further control unit 100b, which is intended in particular for fail-safe operation of the first control unit 80b.

[0059] The electrical supply paths 24b, 26b each have an auxiliary power supply path 36b, 38b. In contrast to the first embodiment, the auxiliary power supply paths 36b, 38b each have two auxiliary power supply lines 82b, 84b, 86b, 88b, which can be selectively supplied with electrical energy. The auxiliary power supply paths 36b, 38b each have a switching module 90b, 92b, which allows switching between the two auxiliary power supply lines 82b, 84b, 86b, 88b. The switching modules 90b, 92b are connected downstream of the respective DC / AC converters 44b, 46b of the respective auxiliary power supply paths 36b, 38b. Furthermore, the auxiliary power supply paths 36b, 38b have a switching unit 94b, via which the second auxiliary power supply line 84b of the first auxiliary power supply path 36b and the second auxiliary power supply line 88b of the second auxiliary power supply path 38b can be electrically coupled to each other.This allows switching between the two auxiliary power supply paths 36b, 38b to be carried out using only two switching modules 90b, 92b, which are designed as circuit breakers. The switching modules 40b, 42b for connecting the peripheral switching circuit of the fuel cell units 18b, 20b to the auxiliary power supply paths 36b, 38b can be designed as simple switches.

[0060] The Fig. Figure 3 shows a fuel cell cluster 10c according to the invention in a third embodiment. The fuel cell cluster 10c is intended for supplying an infrastructure 12c, in particular a critical infrastructure 12c. The infrastructure has several consumers 14c, 16c. The fuel cell cluster 10c is designed as a fail-safe fuel cell cluster. The fuel cell cluster 10c is designed for the safe supply of the infrastructure 12c to be supplied. The fuel cell cluster 10c has several fuel cell units 18c, 20c. The fuel cell units 18c, 20c are designed as SOFC fuel cell units. The fuel cell units 18c, 20c can be configured in the same way as in the first embodiment.

[0061] The fuel cell cluster 10c has an electrical supply module 22c. The electrical supply module 22c is designed to supply the infrastructure 12c with the electrical energy generated by the fuel cell units 18c and 20c. The supply module 22c has a first electrical supply path 24c. Electrical energy from all fuel cell units 18c and 20c of the fuel cell cluster 10c can be supplied to the infrastructure 12c via the first electrical supply path 24c. The supply module 22c has a second electrical supply path 26c. Electrical energy from all fuel cell units 18c and 20c of the fuel cell cluster 10c can be supplied to the infrastructure 12c via the second electrical supply path 26c.Via the second supply path 26c of the supply module 22c, electrical energy from all fuel cell units 18c, 20c of the fuel cell cluster 10c can be supplied to the infrastructure 12c to be supplied as an alternative to the first supply path 24c.

[0062] The supply module 22c has a switching module 28c, 30c for each fuel cell unit 18c, 20c of the fuel cell cluster 10c. The respective fuel cell unit 18c, 20c can be electrically connected to either the first electrical supply path 24c or the second supply path 26c via the corresponding switching module 28c, 30c. The electrical supply paths 24c, 26c each have a supply line 32c, 34c.

[0063] Electrical supply paths 24c and 26c each have a DC / AC converter 44c and 46c, respectively. Electrical supply paths 24c and 26c each have an energy storage device 48c and 50c, respectively. Supply paths 24c and 26c each have a DC / DC converter 52c and 54c, respectively. The supply module 22c has a switching module 60c and 62c for each consumer 14c and 16c of the infrastructure 10c. Supply paths 24c and 26c each have a DC / AC converter 64c and 66c, respectively. Supply paths 24c and 26c each have a transformer 68c and 70c, respectively. Transformer 68c is assigned to the first supply path 24c. Supply paths 24c and 26c each have a first disconnect switch 72c and 74c, respectively. Supply paths 24c and 26c each have a second disconnect switch 76c and 78c, respectively. The fuel cell cluster 10c has a control unit 80c.The control unit 80c is intended for controlling the fuel cell units 18c and 20c and the components of the supply paths 24c and 26c. The fuel cell cluster 10c has a further control unit 100c, which is intended in particular for fail-safe operation of the first control unit 80c.

[0064] In contrast to the previous embodiments, fuel cell units 18c, 20c can be operated with direct current. The peripheral devices of the fuel cell units 18c, 20c can also be operated with direct current. The peripheral devices of the fuel cell units 18c, 20c are supplied by an internal power supply within the fuel cell units 18c, 20c. Therefore, in this embodiment, the supply paths 24c, 26c do not have an auxiliary power supply path. This advantageously allows for component savings. One function of the fuel cell cluster 10c, in particular a method for ensuring the reliable supply of the infrastructure 12c, essentially corresponds to that of the first embodiment.

[0065] The Fig.Figure 4 shows a fuel cell cluster 10d according to the invention in a fourth embodiment. The fuel cell cluster 10d is intended for supplying an infrastructure 12d, in particular a critical infrastructure 12d.

[0066] The infrastructure includes several consumers 14d, 16d. The fuel cell cluster 10d is designed as a fail-safe fuel cell cluster. The fuel cell cluster 10d is designed to reliably supply the infrastructure 12d. The fuel cell cluster 10d includes several fuel cell units 18d, 20d. The fuel cell units 18d, 20d are designed as SOFC fuel cell units. The fuel cell units 18d, 20d can be configured identically to those in the first embodiment.

[0067] The fuel cell cluster 10d has an electrical supply module 22d. The electrical supply module 22d is designed to supply the infrastructure 12d with the electrical energy generated by the fuel cell units 18d and 20d. The supply module 22d has a first electrical supply path 24d. Electrical energy from all fuel cell units 18d and 20d of the fuel cell cluster 10d can be supplied to the infrastructure 12d via the first electrical supply path 24d. The supply module 22d has a second electrical supply path 26d. Electrical energy from all fuel cell units 18d and 20d of the fuel cell cluster 10d can be supplied to the infrastructure 12d via the second electrical supply path 26d.Via the second supply path 26d of the supply module 22d, electrical energy from all fuel cell units 18d, 20d of the fuel cell cluster 10d can be supplied to the infrastructure 12d to be supplied as an alternative to the first supply path 24d.

[0068] The supply module 22d has a switching module 28d, 30d for each fuel cell unit 18d, 20d of the fuel cell cluster 10d. The respective fuel cell unit 18d, 20d can be electrically connected to either the first electrical supply path 24d or the second supply path 26d via the corresponding switching module 28d, 30d. The electrical supply paths 24d, 26d each have a supply line 32d, 34d.

[0069] Electrical supply paths 24d and 26d each have a DC / AC converter 44d and 46d, respectively. Electrical supply paths 24d and 26d each have an energy storage device 48d and 50d, respectively. Supply paths 24d and 26d each have a DC / DC converter 52d and 54d, respectively. The supply module 22d has a switching module 60d and 62d for each consumer 14d and 16d of the infrastructure 12d. Supply paths 24d and 26d each have a DC / AC converter 64d and 66d, respectively. Supply paths 24d and 26d each have a transformer 68d and 70d, respectively. Transformer 68d is assigned to the first supply path 24d. Supply paths 24d and 26d each have a first disconnect switch 72d and 74d, respectively. Supply paths 24d and 26d each have a second disconnect switch 76d and 78d, respectively. The fuel cell cluster 10d has a control unit 80d.The control unit 80d is intended for controlling the fuel cell units 18d and 20d and the components of the supply paths 24d and 26d. The fuel cell cluster 10d has a further control unit 100d, which is primarily intended for fail-safe operation of the first control unit 80d.

[0070] In contrast to the previous embodiments, the fuel cell units 18d, 20d are designed to provide an alternating voltage. The fuel cell units output an alternating voltage that can be fed directly onto the supply lines 32d, 34d of the corresponding supply paths 24d, 26d via the corresponding switching modules 28d, 30d. In this embodiment as well, the supply paths 24d, 26d do not have auxiliary power supply paths.

[0071] Supply paths 24d and 26d each have an additional AC / DC converter 96d and 98d, respectively. The AC / DC converters 96d and 98d are each connected upstream of the energy storage devices 48d and 50d of the corresponding supply path 24d and 26d. A function of the fuel cell cluster 10d, in particular a method for ensuring the reliable supply of the infrastructure 12d, essentially corresponds to that of the first embodiment.

Claims

[1] Fuel cell cluster, in particular SOFC cluster, for supplying power to an infrastructure (12a; 12b; 12c; 12d), in particular a critical infrastructure, with a plurality of fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d), in particular a plurality of SOFC fuel cell units, with an electrical supply module (22a; 22b; 22c; 22d) for supplying the infrastructure to be supplied (12a; 12b; 12c; 12d) with electrical energy from the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d), wherein the electrical supply module (22a; 22b; 22c; 22d) has an electrical supply path (24a; 24b; 24c; 24d), via which electrical energy of all fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) can be supplied to the infrastructure (12a; 12b; 12c; 12d) to be supplied, characterized byin that the supply module (22a; 22b; 22c; 22d) has a second electrical supply path (26a; 26b; 26c; 26d) via which electrical energy of all fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) of the infrastructure to be supplied (12a; 12b; 12c; 12d) can be supplied as an alternative to the first supply path (24a; 24b; 24c; 24d). [2] Fuel cell cluster according to claim 1, characterized by that the supply module (22a; 22b; 22c; 22d) has a switching module (28a, 30a; 28b, 30b; 28c, 30c; 28d, 30d) for each fuel cell unit (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d), by means of which the respective fuel cell unit (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) can be selectively connected to a supply line (32a; 32b; 32c; 32d) of the first supply path (24a; 24b; 24c; 24d) or to a supply line (34a; 34b; 34c; 34d) of the second supply path (26a; 26b; 26c; 26d) can be electrically coupled. [3] Fuel cell cluster according to claim 1 or 2, characterized by that the electrical supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have an auxiliary power supply path (36a, 38a; 36b, 38b; 36c, 38c; 36d, 38d) for supplying the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) with an alternating current, which is connected via a DC / AC converter (44a, 46a; 44b, 46b; 44c, 46c; 44d, 46d) to a supply line (32a, 34a; 32b, 34b; 32c, 34c; 32d, 34d) of the respective supply path (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d). [4] Fuel cell cluster according to one of the preceding claims, characterized byin that the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have an energy storage device (48a, 50a; 48b, 50b; 48c, 50c; 48d, 50d) which is intended to be charged in a normal operating state and to support the power supply of the infrastructure (12a; 12b; 12c; 12d) in an operating state with increased and / or dynamically fluctuating power demand. [5] Fuel cell cluster according to one of the preceding claims, characterized by that the energy stores (48a, 50a; 48b, 50b; 48c, 50c; 48d, 50d) of the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) are each connected via a DC / DC converter (52a, 54a; 52b, 54b; 52c, 54c; 52d, 54d) to a supply line (32a, 34a; 32b, 34b; 32c, 34c; 32d, 34d) of the respective supply path (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d). [6] Fuel cell cluster according to one of the preceding claims, characterized bythat the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have a DC / AC converter (64a, 66a; 64b, 66b; 64c, 66c; 64d, 66d). [7] Fuel cell cluster according to one of the preceding claims, characterized by that the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have a transformer (68a, 70a; 68b, 70b; 68c, 70c; 68d, 70d). [8] Fuel cell cluster according to one of the preceding claims, characterized by that the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have a consumer power supply line (56a, 58a; 56b, 58b; 56c, 58c; 56d, 58d) to which consumers (14a, 16a; 14b, 16b; 14c, 16c; 14d, 16d) of the infrastructure to be supplied (12a; 12b; 12c; 12d) are connected. [9] Fuel cell cluster according to one of the preceding claims, characterized byin that the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) each have at least one isolating switch (72a-78a; 72b-78b; 72c-78c; 72d-78d) via which an electrical connection between a supply line (32a, 34a; 32b, 34b; 32c, 34c; 32d, 34d) and a consumer power supply line (56a, 58a; 56b, 58b; 56c, 58c; 56d, 58d) of the respective supply path (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d) can be severed. [10] Fuel cell cluster according to one of the preceding claims, characterized by a control or regulating unit (80a; 80b; 80c; 80d) which is provided for controlling the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) and the components of the supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d). [11] Method for operating a fuel cell cluster (10a; 10b; 10c; 10d) with a plurality of fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) and with a supply module (22a; 22b; 22c; 22d) having two electrical supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d), characterized by in that in one method step the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) can be electrically coupled optionally to the first supply path (24a; 24b; 24c; 24d) or the second supply path (26a; 26b; 26c; 26d). [12] Method according to claim 11, characterized byin that, in an operating state in which there is a fault in one of the two supply paths (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d), the fuel cell units (18a, 20a; 18b, 20b; 18c, 20c; 18d, 20d) for supplying the infrastructure (12a; 12b; 12c; 12d) are electrically connected to the infrastructure (12a; 12b; 12c; 12d) to be supplied via the other supply path (24a, 26a; 24b, 26b; 24c, 26c; 24d, 26d).

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