Power supply device

Abstract

The invention relates to a power supply device (1) having a plurality of fuel cell units (12) arranged in parallel strands (50, 60, 70), wherein each strand (50, 60, 70) has at least two fuel cell units (12) connected in series or at least two groups (13, 13'), connected in series, of fuel cell units (12). According to the invention, the strands (50, 60, 70) are interconnected in each case at a node point by means of at least one cross connector (90, 90', 90'', 90'''), wherein the node points (92, 92') are formed between two fuel cell units (12), connected in series, of a strand (50, 60, 70) or between two groups (13, 13') of fuel cell units (12) of a strand (50, 60, 70).

Description

[0001] Description

[0002] title

[0003] The invention relates to an energy supply device.

[0004] State of the art

[0005] To achieve higher power outputs, it is known to interconnect multiple fuel cell units. It is also known to connect the fuel cell units electrically in strings. It is also known to connect the strings electrically in parallel. If one of the fuel cell units fails or experiences problems, this can lead to the failure of the entire string.

[0006] Disclosure of the invention

[0007] The invention relates to an energy supply device comprising a plurality of fuel cell units arranged in parallel strings, each string comprising at least two fuel cell units or two groups of fuel cell units. It is advantageous that the strings are each connected to one another at a node via at least one cross-connector. Furthermore, it is advantageous that the nodes are formed between two series-connected fuel cell units of a string or between two groups of fuel cell units of a string. A fuel cell unit is connected in series with at least one further fuel cell unit and in parallel with at least one further fuel cell unit.Alternatively, a single group of fuel cell units is connected in series with at least one other group of fuel cell units and in parallel with at least one other group of fuel cell units. This advantageously allows problems in individual fuel cell units or groups of fuel cell units to be compensated for. This prevents the entire power supply system or large parts of the power supply system from failing.

[0008] The measures listed in the subclaims result in advantageous further developments and improvements of the energy supply device specified in the main claim.

[0009] An advantageous development is that the fuel cell units or groups of fuel cell units are interconnected in parallel and series in a matrix-like manner. This results in a matrix-like interconnection.

[0010] A beneficial development has been shown to be the integration of fuses or electrical switches into the cross-connectors. The function of the electrical cross-connector can be activated or deactivated. At the same time, fuses represent a simple way to prevent damage in the event of a fault.

[0011] An advantageous development is that at least one, and in particular all, of the fuses are designed as bonding wires. Such a fuse represents a simple and cost-effective way to protect the power supply device and its components.

[0012] An advantageous development has been shown for at least one group of fuel cell units to have at least two fuel cell units connected in parallel and / or series. This advantageously increases flexibility and reduces the risk of failure. An advantageous development is for at least one group of fuel cell units or at least one fuel cell unit to have a serially arranged voltage converter, in particular a DC / DC converter. This advantageously allows the voltages to be adjusted.

[0013] An advantageous further development is that each cross connector connects two nodes of two strands.

[0014] It has been shown that an advantageous further development is that the groups of fuel cell units, in particular those connected in parallel to one another, each have an identical number of fuel cell units.

[0015] The drawings schematically illustrate embodiments of the invention and explain them in more detail in the following description.

[0016] Figure 1 shows a schematic circuit diagram of an embodiment of a fuel cell device;

[0017] Figure 2 shows schematically the electrical circuitry of a power supply device according to an embodiment;

[0018] Figure 3 shows schematically the electrical circuitry of a power supply device according to a further development; and

[0019] Figure 4 shows the process flow of a method for regulating the fuel cell units.

[0020] In the following, descriptions of the elements with a reference symbol without an apostrophe always also refer to the elements with one or more apostrophes.

[0021] The invention relates to an energy supply device 1. The energy supply device 1 comprises at least one fuel cell device 10 and a plurality of fuel cell units 12. Figure 1 shows an example of the structure of a fuel cell device 10. Figure 2 shows an example of the structure of an energy supply device 1 with six fuel cell units 12. Figure 3 shows an example of the structure of an energy supply device 1 with six groups of fuel cell units 12. Figures 2 and 3 are simplified in that only the electrical paths are shown schematically. It is self-evident that the energy supply device 1 shown in Figures 2 and 3 also has additional processor units 14 in addition to the fuel cell units 12. The processor units 14 are described in more detail below in Figure 1.As described below, the fuel cell units 12 and the processor units 14 can be combined in any desired manner to form a fuel cell device 10. A fuel cell device 10 can also form a group of fuel cell units.

[0022] Figure 1 shows a schematic circuit diagram of an embodiment of a fuel cell device 10. The fuel cell device 10 comprises, for example, two fuel cell units 12. Preferably, more than the two fuel cell units 12 shown in Figure 1 can be formed.

[0023] In the exemplary embodiment shown, the fuel cell units 12 are designed as a fuel cell stack, which has a plurality of fuel cells, in the present case solid oxide fuel cells (SOFC).

[0024] Furthermore, the fuel cell device 10 comprises a plurality of processor units 14. The number and scaling of the processor units 14 depends on the number of fuel cell units 12 as well as on the design and structure of the entire energy supply device 1.

[0025] In the context of this invention, a "processor unit" 14 is to be understood in particular as a unit or component of the fuel cell device 10 or of the energy supply device 1, which is not a fuel cell unit 12. In the present case, the processor units 14 are units for the chemical and / or thermal pre- and / or post-processing of at least one medium to be converted and / or converted in a fuel cell unit 12, such as an oxidation medium, in particular air and / or oxygen, and / or an exhaust gas and / or a fuel, preferably a combustible gas, in particular natural gas or hydrogen.

[0026] One of the processor units 14 is a heat exchanger 18 arranged in an air supply 16 for heating an oxidation medium, in particular oxygen-containing air L, supplied to the fuel cell units 12. In the present case, the oxidation medium, in particular the air L, is supplied, for example, during normal operation, to a cathode chamber 20 of the fuel cell units 12, while reformed fuel RB, in this case hydrogen or natural gas, is supplied to an anode chamber 22. In the fuel cell units 12, the reformed fuel RB is electrochemically converted with the aid of oxygen from the air L, generating electricity and heat. Electrical energy is generated.

[0027] The reformed fuel RB is produced by supplying fuel B, in particular natural gas or hydrogen or methane or coal gas, to the fuel cell device 10 via a fuel supply 24, which fuel B is reformed in a further processor unit 14, in the present case a reformer 26.

[0028] Furthermore, the fuel cell units 12 are connected on the exhaust side to another processor unit 14, in this case to an afterburner 28. Exhaust gas from the fuel cell units 12 is supplied to the afterburner 28, in this case cathode exhaust gas KA via a cathode exhaust gas duct 30 and a portion of the anode exhaust gas AA via an anode exhaust gas duct 32. The cathode exhaust gas KA contains unused oxidation medium, in particular air L, or unused oxygen, while the anode exhaust gas AA contains possibly unreacted, reformed fuel RB and / or possibly unreformed fuel B. By means of the afterburner 28, the anode exhaust gas AA, or the unreacted, reformed fuel RB possibly contained therein and / or the unreformed fuel B possibly contained therein, is combusted with the admixture of the cathode exhaust gas KA, or the oxygen of the oxidation medium, in particular the air L, contained therein, whereby additional heat can be generated.

[0029] The hot exhaust gas A produced during combustion in the afterburner 28 is discharged from the afterburner 28 via an exhaust gas duct 34 through another processor unit 14, in this case via a heat exchanger 36. The heat exchanger 36 is in turn fluidly connected to the reformer 26, so that heat is transferred from the hot exhaust gas A to the fuel B supplied to the reformer 26. Accordingly, the heat of the hot exhaust gas A can be used for reforming the supplied fuel B in the reformer 26.

[0030] Downstream of the heat exchanger 36, a further processor unit 14, in this case the heat exchanger 18, is located in the exhaust duct 34, so that the remaining heat of the hot exhaust gas A can be transferred to the supplied oxidation medium, in particular air L in the air supply 16. Accordingly, the remaining heat of the hot exhaust gas can be used to preheat the supplied oxidation medium, in particular the air L in the air supply 16.

[0031] Furthermore, the fuel cell device 10 has a return line 38, by means of which a portion of the anode exhaust gas AA can be diverted from the anode exhaust gas line 32 and fed to an anode recirculation circuit 40. The diverted anode exhaust gas AA passes through a further processor unit 14, in this case a further heat exchanger 39.

[0032] By means of the anode recirculation circuit 40, the branched portion of the anode exhaust gas AA can be returned or recirculated to the respective anode chamber 22 of the fuel cell units 12 and / or the reformer 26, so that any unreacted, reformed fuel RB contained in the branched anode exhaust gas AA can be subsequently converted in the fuel cell unit 12 and / or any unreformed fuel B contained in the branched anode exhaust gas AA can be subsequently reformed in the reformer 26. This can further increase the efficiency of the fuel cell device 10. In addition, fresh fuel B can be mixed with the branched anode exhaust gas AA recirculated in the anode recirculation circuit 40 via the fuel supply line 24. By means of the additional heat exchanger

[0033] 39, heat can then be transferred from the branched anode exhaust gas AA from the return line 38 to the fuel mixture in the anode recirculation circuit 40 resulting from the addition of the fresh fuel B for thermal processing.

[0034] Via compressors 42 in the respective lines, the supply of an oxidation medium, in particular of oxidation media, preferably air L in the air supply 16, the supply of fuel B in the fuel supply 24 and the recirculation rate of the anode exhaust gas AA in the anode recirculation circuit

[0035] 40 are regulated and / or coordinated.

[0036] Preferably, the fuel cell device has a heating element 44 for, in the present case, additional heating of the oxidation medium supplied to the fuel cell units 12, in particular air L in a bypass line 46, whereby the operating efficiency of the fuel cell device 10 is increased.

[0037] The invention is not limited to solid oxide fuel cells. Rather, any fuel cell can be embodied. For example, the fuel cells can also be embodied as alkaline fuel cells (AFCs), low-temperature polymer electrolyte fuel cells (LT-PEMFCs), high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs), direct methanol fuel cells (DMFCs), phosphoric acid fuel cells (PAFCs), or molten carbonate fuel cells (MCFCs). The fuels or oxidation media used differ accordingly. Examples of fuels are hydrogen, alcohols (ethanol, propanol, glycerol, methanol), methane, coal gas, ammonia reformate gas, especially methanol. Examples of oxidation media are air, especially atmospheric oxygen, oxygen, hydrogen peroxide, nitric acid, or halogens.

[0038] Depending on the fuel cell used in the fuel cell unit 12, the process units 14 are adapted.

[0039] Figure 2 schematically illustrates the electrical circuitry of a power supply device 1. The power supply device 1 comprises, for example, three strings 50, 60, 70, each with two fuel cell units 12. The number of fuel cell units 12 is not limited to two per string. The fuel cell units 12 of a string 50, 60, 70 are interconnected in series, for example.

[0040] The strings 50, 60, and 70 are electrically connected in parallel. According to the invention, the number of strings 50, 60, and 70 can be chosen arbitrarily. The number of fuel cell units 12 per string can also be chosen arbitrarily.

[0041] According to a first embodiment, the fuel cell units 12 of a string 50, 60, 70 form a fuel cell device 10. Accordingly, Figure 2 shows one fuel cell device 10 per string, i.e. three fuel cell devices 10.

[0042] Contrary to the example in Figure 1, a fuel cell device 10 can also have more or fewer than the two fuel cell units 12 shown in Figure 1. Accordingly, the processor units 14 required by a fuel cell unit are adapted in number, power, and dimensions. Preferably, each fuel cell unit 12 requires a plurality of processor units 14 as shown in Figure 1.

[0043] Individual processor units 14 can be designed and configured such that they share multiple fuel cell units 12. For example, Figure 1 shows two fuel cell units 12 and a plurality of processor units 14 for supplying them.

[0044] According to a further development, individual processor units 14 can simultaneously supply multiple fuel cell units 12. A single processor unit 14 can also supply fuel cell units 12 from more than one string 50, 60, 70. In particular, one compressor 42 can be provided for two or more fuel cell units 12. The air supply 16 can also be used for many, in particular all, fuel cell units 12.

[0045] The strands 50, 60, 70 are connected to one another via at least one cross-connector 90. For example, three cross-connectors 90', 90", 90'" are formed. The cross-connectors 90 connect two strands 50, 60, 70 at one of the nodes 92, which are formed between two serially arranged fuel cell units 12.

[0046] In particular, the cross connector 90' connects a node 92 of the first strand 50 to a node 92 of the second strand 60. The cross connector 90' connects the first strand 50 to the second strand 60. In particular, the cross connector 90" connects a node 92 of the second strand 60 to a node 92 of the third strand 70. The cross connector 90" connects the second strand 60 to the third strand 70. In particular, the cross connector 90'" connects a node 92 of the third strand 70 to a node 92 of the first strand 50. The cross connector 90'" connects the third strand 70 to the first strand 50. In particular, the cross connector 90"' is optional. The cross connector 90'" is necessary in particular when the cross connector 90 has a component. The cross connector 90 establishes an electrical connection between two nodes 92, in particular strands 50, 60, 70.

[0047] Preferably, a matrix-like parallel and serial connection of the fuel cell units 12 results. If one of the fuel cell units 12 fails, in particular due to maintenance, damage, or aging, the energy supply device 1 can still continue to provide energy.

[0048] According to a further development, at least one of the cross-connectors 90 has an additional electrical component 82 or an electrical circuit. In particular, the electrical component 82 can be designed as a fuse, switch, diode, or converter, preferably a voltage converter, or a combination thereof. Preferably, a fuse and a diode or a fuse and a switch would be possible.

[0049] A diode would have to be installed in such a way that it opens in the desired current flow direction and blocks in the opposite current direction.

[0050] The fuse can preferably be designed as a bonded fuse. The switch can be designed, in particular, as a thyristor, relay, contactor, pyroelectric switch, or semiconductor switch, in particular a transistor, preferably a field-effect transistor, for example a MOSFET, JFET, or bipolar transistor. It is also conceivable for a combination of various of these switches or fuses to be designed. A parallel connection of several semiconductor switches, transistors, field-effect transistors, MOSFETs, JFETs, or bipolar transistors is also conceivable. The electrical component is advantageously formed in all cross-connectors that would have the same potential without the electrical component. In particular, all cross-connectors that lead to a parallel connection of two fuel cell units 12.

[0051] According to a further development, some or all of the strands 50, 60, 70 have at least one electrical component 80. Preferably, a component 80 is assigned to at least one fuel cell unit 12. In particular, each fuel cell unit 12 is assigned a component 80. The fuel cell unit 12 and the assigned component 80 are connected in series with one another, in particular. Preferably, at least one electrical component is formed between at least one, in particular all, nodes 92 (including nodes 92') of a strand 50, 60, 70.

[0052] Component 80 can be designed, in particular, as a fuse, switch, diode, or converter. This preferably compensates for inequalities between the fuel cell units. Such inequalities arise, for example, during startup or shutdown, due to minimal temperature differences between the fuel cell units. These inequalities lead, in particular, to differing current intensities in the individual strings.

[0053] Training as a converter has the disadvantage that converters are more expensive. Using converters also involves the use of additional components, which can create additional sources of error.

[0054] The fuse can preferably be designed as a bonded fuse. The switch can be designed, in particular, as a thyristor or semiconductor switch, preferably a MOSFET.

[0055] Component 80 can preferably be designed as a diode, semiconductor switch, or relay. During the warm-up and cool-down phases of the energy supply device 1, the individual fuel cell units 12 generally have different voltages and internal resistances. The reason for this is that the warm-up or cool-down process is generally not completely synchronous. This results in the voltage of the fuel cell units 12 differing from the voltage of a parallel-connected fuel cell unit 12 if they were not connected in parallel. However, since the voltage in parallel connections is always the same without any interruption at 80 or 82, compensating currents flow, which can lead to damage, in particular cell oxidation or unwanted aging, of the fuel cell units 12. This prevents current from flowing into the fuel cell units 12 in the opposite direction to what is actually intended.The components 80 designed as diodes or corresponding switches, relays, thyristors, MOSFETs or similar prevent the flow of such compensating currents.

[0056] According to an advantageous development, the components 80 are each designed as voltage converters, in particular DC / DC converters. According to an advantageous development, at least one electrical component 80 per row can be omitted.

[0057] It is advantageous that by installing, for example, relays, thyristors, semiconductor switches, field-effect transistors, in particular MOSFETs, or bipolar transistors or diodes at the position of the component 80, it can be easily prevented that, in particular during normal operation and / or start-up operation and / or shut-down operation, a defect, in particular a fuel cell unit-internal short circuit, reduction of the active anodes or cathode area, reduction of the generated cell voltage, imbalance between the fuel cell units, increase of the internal resistance in a fuel cell unit 12 leading to a negative influence of electrically parallel connected

[0058] Fuel cell units 12. Furthermore, different performance during start-up and / or shut-down can be compensated.

[0059] An advantageous development is that a control unit is provided that controls the components 80. In particular, the control can be carried out depending on detected defects or errors. Such errors or defects include, for example, a short circuit within the fuel cell unit, a reduction in the active anode or cathode area, a reduction in the generated cell voltage, and an increase in the internal resistance.

[0060] In particular, the control unit can be designed to carry out scenario calculations, in particular continuously, which check the usefulness of shutting down individual strings 50, 60, 70 or fuel cell units 12 or groups of fuel cell units 12 according to one or more of the following criteria. A first criterion is the maximization of the total electrical power of the entire energy supply device 1. A further criterion is the achievement of maximum efficiency, in particular at a predetermined target power. A further criterion is the achievement of maximum efficiency, in particular at a predetermined target power. A further criterion is the achievement of minimum aging, in particular individually for each fuel cell unit 12.A further criterion is compliance with specifications (grid codes) for rapid load changes, in particular, individual or multiple fuel cell units 12 at partial load, in order to enable a power increase or reduction within a specified time. Another criterion is continued operation of the system when a fuel cell unit 12 is deactivated.

[0061] As already explained, the electrical component 80 and / or 82 can be designed as a switch, in particular an electrical switch, preferably a semiconductor switch, for example a transistor. This allows the individual fuel cell units 12 to be electrically isolated between two nodes 92. This has no direct effects on the other fuel cell units 12.

[0062] From a mathematical perspective, the power supply device 1 shown in Figure 2 has two rows and three columns. The columns correspond to the strands. The rows have the same voltage if a cross-connector 90 is present, but it is not provided with an electrical component 82.

[0063] Figure 3 shows a further embodiment. In contrast to the embodiment shown in Figure 2, individual fuel cell units 12 are replaced by groups 13 of fuel cell units 12.

[0064] In particular, by way of example, each group 13 of fuel cell units 12 comprises two fuel cell units 12. Preferably, each group 13 of fuel cell units 12 could form a fuel cell device 10. Preferably, each group 13 of fuel cell units 12 can also comprise more than two fuel cell units 12.

[0065] The groups 13' of fuel cell unit 12 of the first row are interconnected in series, for example. The fuel cell unit 12 of group 13' of fuel cell unit 12 and the optional component 80 are connected in series between two nodes 92.

[0066] The 13" groups of fuel cell unit 12 of the second row are interconnected in parallel, for example. The fuel cell unit 12 of the 13" group of fuel cell unit 12 and the optional component 80 are connected in series between two nodes 92.

[0067] Preferably, a mixed connection, i.e., parallel and serial, is also conceivable. This preferably requires at least four or more fuel cell units 12 per group 13.

[0068] According to an advantageous development, individual fuel cell units 12 can be controlled such that the current and voltage established between two nodes 92 are equalized to the parallel-connected fuel cell units 12. Such control is also referred to below as regulation.

[0069] Preferably, processor units 14 used for regulation are each designed separately for the individual fuel cell units 12 or groups of fuel cell units 12 to be regulated.

[0070] Preferably, the regulation 120 is carried out by corresponding control 122 of a processor unit 14, in particular of several processor units 14. The method 100 and its method steps are explained in detail in Figure 4.

[0071] With an electrically parallel connection according to Figure 2, a forced voltage equalization occurs between the nodes 92, 92'. A forced voltage equalization can lead to an asymmetrical current distribution, particularly due to aging and / or temperature differences and / or manufacturing tolerances between the fuel cell units 12.

[0072] The resulting current depends on the internal resistance of the fuel cell units 12. The internal resistance depends, for example, on the temperature of the fuel cell unit 12, the aging of the fuel cell unit 12, the supplied oxidation medium, and the supplied fuel.

[0073] In particular, fuel cell units 12 with many adjacent fuel cell units 12 are additionally heated by these. A warmer fuel cell unit 12 has lower thermal losses. Warmer fuel cell units 12 also have a lower internal resistance. The lower internal resistance leads to an increased current, which in turn leads to an increased temperature. A spiral can result.

[0074] In the exemplary embodiments according to Figures 2 and 3, an optional converter 98 is provided. This is preferably a DC / AC voltage converter that converts the direct current generated by the fuel cell unit 12 into alternating current. Public power grids, in particular, and most consumers operate with alternating current.

[0075] Preferably, an additional voltage converter 96 is connected upstream of the optional converter 98. The voltage converter 96 is a DC / DC converter. The additional voltage converter 96 can be omitted if the components 80 themselves are designed as voltage converters, in particular DC / DC converters. The voltage converter 96 is particularly necessary because a defined minimum voltage level is always required upstream of a DC / AC converter 98 so that the DC / AC converter 98 can convert into alternating current reasonably and efficiently. The voltage converter 96 and additionally or alternatively the voltage converters formed at position 80 generate an intermediate circuit voltage 97 with a minimum necessary voltage level so that the voltage converter 98 can operate reasonably and / or efficiently.

[0076] An advantageous development is that voltage converters 96 and 98 are combined in a single device. This advantageously optimizes costs and installation space. The small number of individual components also reduces the probability of failure.

[0077] Preferably, all components 80 are identical. Preferably, all components 82 are identical. In particular, components 80 and 82 may also have differences, but these are based on the fuel cell units 12 with which they are connected in series or parallel.

[0078] Figure 4 shows a method 100 according to the invention.

[0079] In a first method step 110, the current flowing between two nodes is determined. Preferably, all currents are determined.

[0080] The determination 110 is carried out, in particular, by measuring individual currents. The unmeasured currents can then be calculated from the measured currents during the determination.

[0081] Preferably, the currents are determined using a shunt resistor. In particular, the shunt resistor can be arranged according to component 80. The shunt resistor is arranged in series with the fuel cell unit(s) 12 or the group of fuel cell units 12.

[0082] In a further method step 120, the regulation of at least one fuel cell unit 12, in particular several fuel cell units 12, preferably all fuel cell units 12, takes place.

[0083] Regulation 120 comprises changing, in particular increasing or reducing, the supply of a fuel and / or the supply of an oxidation medium and / or the heating of the supplied oxidation medium and / or the heating of the fuel and / or the recirculation rate into the fuel cell unit to be regulated. Regulation 120 achieves a change in the current. The fuel cell units 12 react more sensitively to a change in the supply of fuel than to a change in the oxidation medium and / or the recirculation rate.

[0084] Preferably, each fuel cell unit 12 is individually regulated. Preferably, groups 13 of fuel cell units 12 are regulated. In particular, several fuel cell units 12 can be combined into a group 13, which are then supplied by a processor unit 14. Preferably, the fuel cell units 12 are jointly regulated between two nodes 92, 92'.

[0085] For example, the supply of air L can be regulated by means of a compressor 42 in the air supply 16. A compressor 42 in the fuel supply 24 can regulate the supply of fuel B. A compressor 42 in the anode recirculation circuit 40 can regulate the recirculation rate of the anode exhaust gas AA. In method step 120, individual or multiple fuel cell units 12 are regulated depending on the strand currents determined in method step 110.

[0086] Preferably, the regulation 120 in method step 120 is carried out such that the currents equalize to one another. In particular, the currents differ negligibly after the regulation 120. Preferably, the currents are substantially equal after the regulation.

[0087] In an optional method step 122, individual or multiple processor units 14 are controlled. Control 122 is a sub-step of method step 120. In an optional method step 116, the fuel cell units 12 that are regulated in method step 120 are selected. Preferably, the fuel cell units 12 are selected that have a current that deviates from the other currents by a certain tolerance.

[0088] According to an advantageous development, the aging of individual fuel cell units 12 can also be determined. The selection 116 is then additionally based on the aging of the fuel cell units 12.

[0089] Furthermore, the selection 116 can be made depending on the position of the fuel cell unit 12 relative to other fuel cell units 12. In particular, fuel cell units 12 that have many adjacent fuel cell units 12 tend to be warmer and therefore have a lower internal resistance.

[0090] Preferably, the fuel cell units 12 to be regulated are selected whose determined currents deviate from a defined target current.

[0091] Preferably, the target current is defined. Alternatively or additionally, the target current is determined from the total current. To do this, the total current is divided by the number of strings (50, 60, 70).

Claims

Claims Energy supply device (1), comprising a plurality of fuel cell units (12) arranged in parallel strings (50, 60, 70), wherein each string (50, 60, 70) comprises at least two fuel cell units (12) connected in series or at least two groups (13, 13') of fuel cell units (12) connected in series, characterized in that the strings (50, 60, 70) are connected to each other at a node via at least one cross connector (90, 90', 90“, 90'“), wherein the nodes (92, 92') are formed between two fuel cell units (12) connected in series of a string (50, 60, 70) or between two groups (13, 13') of fuel cell units (12) of a string (50, 60, 70).Energy supply device (1) according to the preceding claim, characterized in that the fuel cell units (12) or groups (13, 13') of fuel cell units (12) are interconnected in parallel and series in a matrix configuration. Energy supply device (1) according to any of the preceding claims, characterized in that fuses or electrical switches are formed in the cross-connectors (90, 90', 90", 90'"). Energy supply device (1) according to any of the preceding claims, characterized in that at least one, in particular all, fuses are designed as bond wires. Energy supply device (1) according to any of the preceding claims, characterized in that at least one group (13, 13', 13") of fuel cell units (12) comprises at least two fuel cell units (12) that are interconnected in parallel and / or series.

6. Energy supply device (1) according to one of the preceding claims, characterized in that at least one group (13, 13', 13") of fuel cell units (12) or at least one fuel cell unit (12) has a series-arranged voltage converter, in particular a DC / DC converter.

7. Energy supply device (1) according to one of the preceding claims, characterized in that each cross connector (90, 90', 90", 90'") connects two nodes (92, 92') of two strands (50, 60, 70) to each other.

8. Energy supply device (1) according to one of the preceding claims, characterized in that the groups (13, 13', 13") of fuel cell units (12), in particular those connected in parallel to each other, each comprise an identical number of fuel cell units (12).

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