Method for operating a fuel cell device

Abstract

The invention is based on a method for operating a fuel cell device (10), in particular a hydrogen-powered SOFC fuel cell device, which has at least one fuel cell unit (12), in particular a fuel cell stack, at least one blower unit (14), at least one heat transfer unit (30), in particular a condensation heat transfer unit, and at least one control and regulating unit (16), with an operating step (18) in which the fuel cell unit (12) obtains electrical energy from a gaseous medium, wherein the blower unit (14) regulates and drives a recirculation circuit (20) in the operating step (18), and wherein operation of the fuel cell device (10) is regulated by means of the control and regulating unit (16) in the operating step (18). It is proposed that in at least one adaptation step (22) a fuel cell utilization factor of the fuel cell unit (12) is adapted, in particular reduced, wherein in parallel the fuel cell utilization factor of the fuel cell device (10) is kept constant.

Description

State of the art

[0001] A method for operating a fuel cell device, in particular a hydrogen-powered SOFC fuel cell device, which has at least one fuel cell unit, in particular a fuel cell stack, at least one blower unit, at least one heat transfer unit, in particular a condensation heat transfer unit, and at least one control and regulating unit, with an operating step in which the fuel cell unit obtains electrical energy from a gaseous medium, wherein the blower unit regulates and drives a recirculation circuit in the operating step and wherein an operation of the fuel cell device is regulated by means of the control and regulating unit in the operating step, has already been proposed. Disclosure of the invention

[0002] The invention is based on a method for operating a fuel cell device, in particular a hydrogen-powered SOFC fuel cell device, which has at least one fuel cell unit, in particular a fuel cell stack, at least one blower unit, at least one heat transfer unit, in particular a condensation heat transfer unit, and at least one control and regulating unit, with an operating step in which the fuel cell unit obtains electrical energy from a gaseous medium, wherein the blower unit regulates and drives a recirculation circuit in the operating step and wherein an operation of the fuel cell device is regulated by means of the control and regulating unit in the operating step.

[0003] It is proposed that in at least one adaptation step, a fuel cell utilization factor of the fuel cell unit is adapted, in particular reduced, while in parallel the fuel cell utilization factor of the fuel cell device is kept constant.

[0004] In this context, a “fuel cell device” is to be understood in particular as a device which is configured to generate electrical energy in one operating step. The fuel cell device is preferably configured to provide an energy system. The fuel cell device is preferably designed as an SOFC fuel cell device, in particular a solid oxide fuel cell. The fuel cell device preferably has a supply element which supplies an energy carrier, for example hydrogen, and / or electrical energy to the fuel cell device. The fuel cell system preferably has a discharge element which discharges exhaust gases and / or electrical energy from a fuel cell system. In particular, it is conceivable for the supply element to supply the fuel cell device with oxygen from the ambient air.Furthermore, it is conceivable for the fuel cell device to be supplied with pure oxygen via the supply element in order to increase the efficiency of the fuel cell device. The supply element and the discharge element are preferably designed as a pipeline. Particularly preferably, the supply element and the discharge element are designed to guide a gaseous medium. In particular, it is conceivable for the fuel cell device to have a heat exchanger which is designed to utilize thermal energy generated in the fuel cell unit. In particular, it is conceivable for the fuel cell device to have a cooling unit in a recirculation circuit which is designed to cool a gaseous medium heated by a blower unit. “Designed” should be understood to mean, in particular, specially programmed, designed and / or equipped.The fact that an object is intended for a specific function should be understood in particular to mean that the object fulfills and / or performs this specific function in at least one application and / or operating state. Preferably, the fuel cell device has a fuel cell utilization factor. In this context, a "fuel cell utilization factor" should be understood in particular as a potential of the releasable electrons.

[0005] In this context, a “fuel cell unit” is to be understood in particular as a unit which is designed to generate electrical energy from a gaseous medium in one operating step. The fuel cell unit is preferably designed as a fuel cell stack. The fuel cell unit is preferably designed to electrochemically generate electrical energy and heat from the chemical energy of an energy carrier. The fuel cell unit is preferably designed to generate electrical energy from a gaseous medium. The fuel cell unit is preferably designed to convert chemical reaction energy of a continuously supplied fuel and an oxidizing agent into electrical energy. Particularly preferably, hydrogen, for example, is used as the fuel and oxygen as the oxidizing agent.Alternatively, other fuels that would appear appropriate to a person skilled in the art, for example methanol, butane, ammonia and / or natural gas, are also conceivable. Preferably, in one operating step, electrical energy is generated in the fuel cell unit between an anode and a cathode. Preferably, the anode splits off the electrons from the fuel. Preferably, the electrons are conducted to the cathode via a connecting element. Preferably, the fuel cell unit has at least one fuel cell. Particularly preferably, the fuel cell unit has a plurality of fuel cells. Preferably, all fuel cells in a fuel cell unit are identical. Alternatively, it is conceivable for the fuel cell units to be differently designed. Preferably, each fuel cell has an anode and a cathode. Preferably, all fuel cells in a fuel cell unit are electrically connected to one another.Preferably, the fuel cells are electrically connected in series or parallel to achieve the desired output voltage and power. Preferably, the fuel cell unit has a fuel cell utilization factor. Preferably, in one operating step, a fuel cell utilization factor of the fuel cell unit is adjusted. Particularly preferably, in one operating step, a fuel cell utilization factor of the fuel cell unit is reduced. Preferably, in one operating step, the fuel cell utilization factor of the fuel cell device is kept constant. Particularly preferably, the fuel cell utilization factor of the fuel cell device is predetermined by the fuel cell device. Preferably, in the operating step, a fuel cell utilization factor of the fuel cell unit is adjusted to an optimized range.An “optimized range” is understood to be an operating point in which higher cell voltages can be achieved without damaging a fuel cell unit.

[0006] In this context, a "blower unit" should be understood in particular to mean an element that accelerates a gaseous medium. Preferably, the blower unit accelerates a gaseous medium to a medium flow. Preferably, the blower unit generates a medium flow of the gaseous medium. Preferably, the blower unit has at least one rotor blade element, via which a rotary movement is converted into a linear movement of the gaseous medium. Preferably, the heat transfer device has a drive unit that drives the at least one rotor blade element in rotation. A "rotor blade element" should be understood in particular to mean an element that converts a converted enthalpy at least substantially entirely or partially into flow energy of a gaseous medium. Preferably, the blower unit is arranged in a recirculation circuit.The blower unit is preferably arranged at least substantially partially, preferably at least substantially, and particularly preferably entirely in a recirculation circuit. The expression “at least substantially” is to be understood as meaning in particular at least 55%, advantageously at least 65%, preferably at least 75%, particularly preferably at least 85%, and particularly advantageously at least 95%. In this context, “at least substantially” is to be understood as meaning in particular that a deviation from a predetermined value deviates by in particular less than 25%, preferably less than 10%, and particularly preferably less than 5% of the predetermined value. The at least one guide vane element is particularly preferably arranged entirely in a recirculation circuit.

[0007] In this context, an “operating step” should be understood to mean, in particular, a method step in which the fuel cell device is operated, in particular regularly and / or continuously. Preferably, in the operating step, electrical energy is generated in a fuel cell unit. Preferably, a computing step and an application step are carried out in the operating step. Preferably, in the operating step, operation of a fuel cell device is regulated and / or monitored by means of a control and regulating unit. Preferably, 100% of the supplied fuel, in particular hydrogen, is used in an operating step. Particularly preferably, in the operating step, the molar flow of the supplied hydrogen corresponds to the molar flow of the condensed water. Preferably, in an operating step, the volume flow upstream of a fuel cell unit is equal to a volume flow downstream of the fuel cell unit.Preferably, only the composition of the volume flow, in particular the composition of the hydrogen-water mixture, is changed in one operating step. Particularly preferably, the hydrogen content of the volume flow downstream of the fuel cell unit is reduced in one operating step compared to the volume flow upstream of a fuel cell unit.

[0008] In this context, a "recirculation circuit" is to be understood in particular as a circuit which is designed to provide a return flow of waste products and / or unused fuel, in particular hydrogen. Preferably, in one operating step, a fuel, in particular hydrogen, is supplied to the recirculation circuit by means of the supply element. Preferably, the recirculation circuit connects a blower unit and a fuel cell unit by means of a circuit. Preferably, a fuel, in particular hydrogen, is supplied between the blower unit and the fuel cell unit by means of the supply element. Preferably, the recirculation circuit directs a volume flow of the discharge element at least partially, preferably to a large extent, from the discharge element to the blower unit.In particular, it is conceivable for the control and regulation unit to continuously regulate the proportion of the diverted volume flow from the diversion element via the speed of the fan unit. Preferably, the recirculation circuit is configured to regulate and ensure a supply to the fuel cell unit in one operating step. Preferably, the recirculation circuit is configured to regulate and maintain pressure and flow regulation of the volume flow in a fuel cell unit in one operating step. In particular, it is conceivable for the recirculation circuit to have a cooling element by means of which the operating temperature of the fuel is regulated in one operating step.

[0009] In this context, a "heat transfer unit" is understood to mean, in particular, a unit designed to transfer heat in the direction of a temperature gradient between at least two, in particular fluid, material flows, in particular in countercurrent operation, crosscurrent operation, and / or the cocurrent principle. The heat transfer unit is preferably designed as a condensation heat transfer unit. The heat transfer unit is preferably designed to transfer heat from at least one fluid material flow, in particular a gaseous medium of the solid oxide fuel cell unit supplied to the anode, in particular to a cooling fluid supplied to the heat transfer unit in at least one operating state.The heat transfer unit preferably has a temperature control element configured to bring the heat transfer unit to a required process temperature by supplying and / or removing thermal energy and / or to at least substantially maintain a required process temperature. The heat transfer unit preferably has a water separation element. In particular, the temperature control element is provided to temperature-control the water separation element to a process temperature at which the water content of the anode exhaust gas condenses. Preferably, the temperature control element is at least partially thermally coupled to the water separation element. In particular, the temperature control element is at least partially formed integrally with the heat transfer unit."Integral" should be understood in particular as being at least materially connected, for example, by a welding process, an adhesive process, an injection molding process, and / or another process deemed appropriate by a person skilled in the art, and / or advantageously formed in one piece, such as by production from a single casting and / or by production using a single- or multi-component injection molding process, and advantageously from a single blank. The heat transfer unit is preferably arranged in a recirculation circuit upstream of the water supply.

[0010] A "control and regulating unit" should be understood in particular to mean a unit with at least one control electronics unit. A "control electronics unit" should be understood in particular to mean a unit with a processor unit and with a memory unit as well as with an operating program stored in the memory unit. The control and regulating unit is preferably configured to adapt an operation of the fuel cell device in an operating step. The control and regulating unit is preferably configured to regulate the blower unit in an adaptation step. The control and regulating unit is preferably configured to adapt an operation of the fuel cell unit in an operating step and to regulate the blower unit in parallel in an adaptation step.Preferably, the control and regulation unit has a user interface via which a user can monitor and control an operating step and / or an adjustment step. In particular, it is conceivable for the control and regulation unit to automatically perform a calculation step, adjustment step, and / or operating step in a cyclic sequence.

[0011] The inventive design of the method for operating a fuel cell device makes it possible to provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to system performance and efficiency can be achieved. In particular, advantageous properties with regard to an operating point can be achieved. In particular, advantageous properties with regard to regulating the fuel utilization rate of the fuel cell unit can be provided. In particular, by regulating the fuel utilization rate of the fuel cell unit, higher cell voltages can be ensured without risking damage to the fuel cell unit. In this way, advantageous properties with regard to maintenance and the service life of the fuel cell device can be provided.

[0012] Furthermore, it is proposed that in at least one adaptation step, the control and regulating unit regulates a blower unit in order to reduce the fuel cell utilization factor of the fuel cell unit. Preferably, in the adaptation step, the speed of the blower unit is regulated by means of the control and regulating unit in order to reduce the fuel cell utilization factor of the fuel cell unit. Preferably, in the adaptation step, the speed of the blower unit is increased by means of the control and regulating unit in order to reduce the fuel cell utilization factor of the fuel cell unit. In this context, an "adaptation step" is to be understood in particular as a method step in which the fuel cell utilization factor of the fuel cell unit is adapted. Preferably, in the adaptation step, the fuel cell utilization factor of the fuel cell unit is reduced.Preferably, in the adjustment step, the proportion of the volume flow of the discharge element into the recirculation circuit is increased in order to reduce the fuel cell utilization factor of the fuel cell unit. Preferably, in the adjustment step, the proportion of exhaust gases and / or unused fuel in a recirculation circuit is increased by increasing the speed of the blower unit in order to reduce the fuel cell utilization factor of the fuel cell unit. This makes it possible to provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to system performance and efficiency can be achieved.

[0013] Furthermore, it is proposed that in at least one adjustment step, a fuel cell utilization factor of the fuel cell unit is adjusted by means of the heat transfer unit, in particular a condensation heat transfer unit. Preferably, in the adjustment step, excess water is separated from the gaseous medium leading to the anode within the recirculation circuit by means of the heat transfer unit. In particular, the excess water is separated from the gaseous medium leading to the anode by condensation in at least one adjustment step. In particular, in the adjustment step, the water is separated by means of the water separation element of the heat transfer unit. Preferably, in the adjustment step, the fuel cell utilization factor of the fuel cell unit is adjusted via the proportion of excess water in the recirculation circuit.Preferably, at least 50%, preferably at least 70%, and particularly preferably at least 90% of the excess water is separated by the heat transfer unit in an adjustment step. In particular, it is conceivable that the fuel cell utilization rate of the fuel cell unit is adjusted by controlling the temperature of the gaseous medium in the recirculation circuit using the temperature control element of the heat transfer unit. This can provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to system performance and efficiency can be achieved.

[0014] It is further proposed that in at least one operating step, a cell voltage of the fuel cell unit is increased by the adjustment of the fuel cell utilization factor of the fuel cell unit carried out in the adjustment step. Preferably, in the operating step, a cell voltage of the fuel cell unit is increased by reducing the fuel cell utilization factor of the fuel cell unit. Preferably, in the operating step, a cell voltage of the fuel cell unit is increased proportionally by reducing the fuel cell utilization factor of the fuel cell unit. Preferably, in the operating step, at a constant fuel cell utilization factor of the fuel cell unit, a cell voltage of the fuel cell unit is increased by reducing the fuel cell utilization factor of the fuel cell unit.Preferably, in the operating step, a cell voltage of the fuel cell unit is increased by reducing the fuel cell utilization rate of the fuel cell unit via a control and regulation unit. In particular, it is conceivable for an adjustment step to be carried out by means of the control and regulation unit in a cyclic sequence. This can provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to system performance and efficiency can be achieved.

[0015] Furthermore, it is proposed that in at least one calculation step, a quantity of the supplied fuel is determined based on the specifications of the fuel cell utilization rate of the fuel cell device. Preferably, in the calculation step, the quantity of the supplied fuel is determined based on the specifications of the fuel cell utilization rate of the fuel cell device (FU SYS ), the number of fuel cells (N Cell ), the Faraday constant (F) and the electric current (I el ). Preferably, in the calculation step, the amount of fuel supplied is calculated based on the specifications of the fuel cell utilization rate of the fuel cell device using the formula n˙H2,Sys,IN=Iel∗Ncell2F∗FUSys calculated. Preferably, the calculation step is carried out in the operating step before an adaptation step. In this context, a “calculation step” should be understood to mean, in particular, a method step in which the amount of fuel supplied is determined. Preferably, in the calculation step, the amount of fuel supplied is calculated based on the specifications of the fuel cell utilization factor of the fuel cell device. Preferably, in the calculation step, a volume flow of the amount of fuel supplied is determined. Preferably, in the operating step, a volume flow of fuel determined in a calculation step is supplied. This makes it possible to provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to system performance and efficiency can be achieved.

[0016] It is further proposed that in at least one operating step, the level of the volume flow is influenced by the choice of the fuel cell utilization factor of the fuel cell unit. Preferably, in the operating step, a low fuel cell utilization factor of the fuel cell unit (FU Stark) a high volume flow is generated. Preferably, in the operating step, a high volume flow is generated in the recirculation flow with a low fuel cell utilization rate of the fuel cell unit. In particular, in the operating step, a high volume flow is generated in the fuel cell unit with a low fuel cell utilization rate of the fuel cell unit. Preferably, in the operating step, the volume flow upstream of a fuel cell unit is equal to a volume flow downstream of the fuel cell unit. Preferably, in the operating step, the composition of the volume flow upstream of a fuel cell unit changes to the volume flow downstream of the fuel cell unit. Preferably, in the operating step, the hydrogen proportion of the volume flow upstream of a fuel cell unit changes to the hydrogen proportion of the volume flow downstream of the fuel cell unit.Preferably, in the operating step, the volume flow rate is determined using the formula:. n˙Stack,IN==Iel∗Ncell2F∗xH2∗FUStack

[0017] Preferably, in the operating step, the amount of hydrogen supplied corresponds to the same amount of condensed water. This can provide advantageous properties with regard to the efficiency of the fuel cell device. In particular, advantageous properties with regard to regulating the fuel utilization rate of the fuel cell unit can be provided.

[0018] The invention further proposes a fuel cell device, in particular a hydrogen-powered SOFC fuel cell device, for carrying out a method according to the invention. Preferably, the fuel cell device is configured to carry out an operating step. Preferably, the fuel cell device is configured to generate electrical energy. Preferably, the fuel cell device has a supply element which supplies an energy carrier, for example hydrogen, and / or electrical energy to the fuel cell device. Preferably, the fuel cell system has a discharge element which discharges exhaust gases and / or electrical energy from a fuel cell system. Preferably, the fuel cell device is configured as an SOFC fuel cell device. Particularly preferably, the fuel cell device is operated with hydrogen.The fuel cell device is preferably constructed in multiple parts. The fuel cell device preferably has at least one fuel cell unit. The fuel cell device preferably has at least one blower unit. The fuel cell device preferably has at least one recirculation circuit. The fuel cell device preferably has a heat transfer unit, in particular a condensation heat transfer unit, in a recirculation circuit, which is configured to reduce excess water from the gaseous medium flowing to the anode by means of condensation. This makes it possible to provide particularly advantageous properties with regard to a method according to the invention for operating a fuel cell device.

[0019] The method according to the invention for operating a fuel cell device is not intended to be limited to the application and embodiment described above. In particular, the method according to the invention for operating a fuel cell device may comprise a number of individual elements, components, and units, as well as method steps, that differs from the number stated herein in order to fulfill a functional function described herein. Furthermore, in the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and can be used arbitrarily. drawing

[0020] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an exemplary embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. Those skilled in the art will also expediently consider the features individually and combine them into useful further combinations.

[0021] They show: Fig. 1 a fuel cell device according to the invention in a schematic representation and Fig. 2 a schematic flow diagram of a method for operating a fuel cell device according to the invention. Description of the embodiment

[0022] Fig. 1 shows a fuel cell device 10, in particular a hydrogen-powered SOFC fuel cell device, for carrying out a method according to the invention. The fuel cell device 10 is configured to carry out an operating step 18. The fuel cell device 10 is configured to generate electrical energy. The fuel cell device 10 has a supply element 28, which supplies an energy carrier, for example hydrogen, and / or electrical energy to the fuel cell device 10. The fuel cell device 10 has a discharge element 26, which discharges exhaust gases and / or electrical energy from a fuel cell device. The fuel cell device 10 is designed as an SOFC fuel cell device. The fuel cell device 10 is operated with hydrogen. The fuel cell device 10 is designed in several parts.The fuel cell device 10 has at least one fuel cell unit 12. The fuel cell device 10 has at least one blower unit 14. The fuel cell device 10 has at least one recirculation circuit 20. In particular, it is conceivable that the fuel cell device 10 is supplied with oxygen from the ambient air via the supply element 28. Furthermore, it is conceivable that the fuel cell device 10 is supplied with pure oxygen via the supply element 28 in order to increase the efficiency of the fuel cell device 10. The supply element 28 and the discharge element 26 are designed as a pipeline. The supply element 28 and the discharge element 26 are designed to conduct a gaseous medium.In particular, it is conceivable for the fuel cell device 10 to have a heat exchanger configured to utilize thermal energy generated in the fuel cell unit 12. The fuel cell device 10 has a heat transfer unit 30, in particular a condensation heat transfer unit, configured to reduce excess water from the gaseous medium flowing to the anode by means of condensation.

[0023] The fuel cell unit 12 is designed as a fuel cell stack. The fuel cell unit 12 is configured to electrochemically generate electrical energy and heat from the chemical energy of an energy carrier. The fuel cell unit 12 is configured to generate electrical energy from a gaseous medium. The fuel cell unit 12 is configured to convert chemical reaction energy of a continuously supplied fuel and an oxidizing agent into electrical energy. For example, hydrogen is used as the fuel and oxygen as the oxidizing agent. Alternatively, other fuels that appear appropriate to a person skilled in the art, such as methanol, butane, ammonia, and / or natural gas, are also conceivable. In an operating step 18, electrical energy is generated in the fuel cell unit 12 between an anode and a cathode. The anode splits off the electrons from the fuel.The electrons are guided to the cathode via a connecting element. The fuel cell unit 12 has at least one fuel cell. The fuel cell unit 12 has a plurality of fuel cells. All fuel cells in a fuel cell unit 12 are identically designed. Alternatively, it is conceivable for the fuel cells to be differently designed. Each fuel cell has an anode and a cathode. All fuel cells of a fuel cell unit 12 are electrically connected to one another. The fuel cells are electrically connected in series or parallel to achieve the desired output voltage and power. The fuel cell unit 12 has a fuel cell utilization factor.

[0024] The blower unit 14 generates a medium flow of the gaseous medium. The blower unit 14 has at least one rotor blade element, via which a rotary movement is converted into a linear movement of the gaseous medium. The blower unit 14 has a drive unit that drives the at least one rotor blade element in rotation. The blower unit 14 is arranged in a recirculation circuit 20. The blower unit 14 is arranged at least substantially partially, preferably at least to a large extent, and particularly preferably entirely in a recirculation circuit.

[0025] In an operating step 14, a fuel, in particular hydrogen, is supplied to the recirculation circuit 20 by means of the supply element 28. The recirculation circuit 20 connects a blower unit 14 and a fuel cell unit 12 by means of a circuit. A fuel, in particular hydrogen, is supplied between the blower unit 14 and the fuel cell unit 12 by means of the supply element 28. The recirculation circuit 20 directs a volume flow of the discharge element 26 at least partially, preferably to a large extent, from the discharge element 26 to the blower unit 14. In particular, it is conceivable for a control and regulating unit 16 to continuously regulate the proportion of the diverted volume flow from the discharge element 26 via the speed of the blower unit 14. The recirculation circuit 20 is configured to regulate and ensure a supply to the fuel cell unit 12 in an operating step 18.The recirculation circuit 20 is configured to regulate and maintain pressure and flow regulation of the volume flow in a fuel cell unit 12 in an operating step 18. The fuel cell device 10 has the heat transfer unit 30, in particular a condensation heat transfer unit, which is configured to reduce excess water from the gaseous medium flowing to the anode by means of condensation. The heat transfer unit 30 is designed as a condensation heat exchanger. The heat transfer unit 30 is provided to transfer heat from at least one fluid material flow, in particular a gaseous medium of the solid oxide fuel cell unit supplied to the anode, in particular to a cooling fluid, which is supplied to the heat transfer unit 30 in at least one operating state.The heat transfer unit 30 has a temperature control element configured to bring the heat transfer unit 30 to a required process temperature and / or to at least substantially maintain a required process temperature by supplying and / or removing thermal energy. The heat transfer unit 30 has a water separation element. In particular, the temperature control element is provided to temperature-control the water separation element to a process temperature at which the water content of the anode exhaust gas condenses. The temperature control element is at least partially thermally coupled to the water separation element. In particular, the temperature control element is at least partially formed integrally with the heat transfer unit 30.The term “one-piece” should be understood in particular as meaning at least materially connected, for example by a welding process, an adhesive process, an injection-molding process and / or another process that appears appropriate to the person skilled in the art, and / or advantageously formed in one piece, such as by production from a casting and / or by production in a single-component or multi-component injection-molding process and advantageously from a single blank.

[0026] The control and regulation unit 16 is configured to adapt the operation of the fuel cell device 10 in an operating step 18. The control and regulation unit 16 is configured to regulate the blower unit 14 in an adaptation step 22. The control and regulation unit 16 is configured to adapt the operation of the fuel cell unit 12 in an operating step 18 and, in parallel, to regulate the blower unit 14 in an adaptation step 22. The control and regulation unit 16 has a user interface via which a user can monitor and control an operating step 18 and / or an adaptation step 22. In particular, it is conceivable for the control and regulation unit 16 to automatically perform a calculation step 24, adaptation step 22 and / or operating step 18 in a cyclic sequence.

[0027] Fig.2 shows a method for operating a fuel cell device 10, in particular a hydrogen-powered SOFC fuel cell device, which has at least one fuel cell unit 12, in particular a fuel cell stack, at least one blower unit 14, at least one heat transfer unit (30), in particular a condensation heat transfer unit, and at least one control and regulation unit 16. The method for operating a fuel cell device 10 has an operating step 18 in which the fuel cell unit 12 generates electrical energy from a gaseous medium, wherein the blower unit 14 regulates and drives a recirculation circuit 20 in the operating step 18, and wherein operation of the fuel cell device 10 is regulated by means of the control and regulation unit 16 in the operating step 18.In at least one adjustment step 22, a fuel cell utilization factor of the fuel cell unit 12 is adjusted, in particular reduced, while in parallel the fuel cell utilization factor of the fuel cell device 10 is kept constant. In the operating step 18, electrical energy is generated in a fuel cell unit 12. In the operating step 18, a calculation step 24 and an application step 22 are carried out. In the operating step 18, the operation of a fuel cell device 10 is regulated and / or monitored by means of a control and regulating unit 16. In the operating step 18, 100% of the supplied fuel, in particular hydrogen, is utilized. In the operating step 18, the molar flow of the supplied hydrogen corresponds to the molar flow of the condensed water. In the operating step 18, the volume flow upstream of a fuel cell unit 12 is equal to a volume flow downstream of the fuel cell unit 12.In operating step 18, only the composition of the volume flow, in particular the composition of the hydrogen-water mixture, is changed. In operating step 18, the hydrogen content of the volume flow downstream of the fuel cell unit 12 is reduced compared to the volume flow upstream of the fuel cell unit 12.

[0028] In operating step 18, a fuel cell utilization factor of the fuel cell unit 12 is adjusted. In operating step 18, a fuel cell utilization factor of the fuel cell unit 12 is reduced. In operating step 18, the fuel cell utilization factor of the fuel cell device 10 is kept constant. The fuel cell utilization factor of the fuel cell device 10 is predetermined by the fuel cell device 10. In operating step 18, a fuel cell utilization factor of the fuel cell unit 12 is adjusted to an optimized range.

[0029] In at least one adjustment step 22, a fuel cell utilization factor of the fuel cell unit 12 is adjusted by means of the heat transfer unit 30, in particular a condensation heat transfer unit. In the adjustment step 22, excess water within the recirculation circuit 20 is separated from the gaseous medium leading to the anode by means of the heat transfer unit 30. In particular, the excess water is separated from the gaseous medium leading to the anode by condensation in at least one adjustment step 22. In particular, in the adjustment step 22, the water is separated by means of the water separation element of the heat transfer unit 30. In the adjustment step 22, the fuel cell utilization factor of the fuel cell unit 12 is adjusted via the proportion of excess water in the recirculation circuit 20.In the adjustment step 22, at least 50% of the excess water is separated by the heat transfer unit 30. In particular, it is conceivable that the fuel cell utilization rate of the fuel cell unit 12 is adjusted by controlling the temperature of the gaseous medium in the recirculation circuit 20 by means of the temperature control element of the heat transfer unit 30.

[0030] In at least one adaptation step 22, the control and regulation unit 16 regulates a blower unit 14 in order to reduce the fuel cell utilization factor of the fuel cell unit 12. In the adaptation step 22, the speed of the blower unit 14 is regulated by means of the control and regulation unit 16 in order to reduce the fuel cell utilization factor of the fuel cell unit 12. In the adaptation step 22, the speed of the blower unit 14 is increased by means of the control and regulation unit 16 in order to reduce the fuel cell utilization factor of the fuel cell unit 12. In the adaptation step 22, the fuel cell utilization factor of the fuel cell unit 12 is reduced. In the adaptation step 22, the proportion of the volume flow of the discharge element 26 into the recirculation circuit 20 is increased in order to reduce the fuel cell utilization factor of the fuel cell unit 12.In the adaptation step 22, the proportion of exhaust gases and / or unused fuel in a recirculation circuit 20 is increased by increasing the speed of the blower unit 14 in order to reduce the fuel cell utilization factor of the fuel cell unit 12.

[0031] In at least one operating step 18, a cell voltage of the fuel cell unit 12 is increased by the adjustment of the fuel cell utilization factor of the fuel cell unit 12 carried out in the adjustment step 22. In the operating step 18, a cell voltage of the fuel cell unit 12 is increased by reducing the fuel cell utilization factor of the fuel cell unit 12. In the operating step 18, a cell voltage of the fuel cell unit 12 is proportionally increased by reducing the fuel cell utilization factor of the fuel cell unit 12. In the operating step 18, with a constant fuel cell utilization factor of the fuel cell unit 12, a cell voltage of the fuel cell unit 12 is increased by reducing the fuel cell utilization factor of the fuel cell unit 12.In the operating step 18, a cell voltage of the fuel cell unit 12 is increased by reducing the fuel cell utilization rate of the fuel cell unit 12 via a control and regulation unit 16. In particular, it is conceivable that an adaptation step 22 is carried out by means of the control and regulation unit 16 in a cyclic sequence.

[0032] In at least one calculation step 24, an amount of fuel supplied is determined based on the specifications of the fuel cell utilization rate of the fuel cell device 10. In the calculation step 24, the amount of fuel supplied is determined based on the specifications of the fuel cell utilization rate of the fuel cell device 10 (FU SYS ), the number of fuel cells (N Cell ), the Faraday constant (F) and the electric current (I el). In the calculation step 24, the amount of fuel supplied is calculated based on the specifications of the fuel cell utilization factor of the fuel cell device 10 using the formula n˙H2,Sys,IN=Iel∗Ncell2F∗FUSys A calculation step 24 is performed in operating step 18 before an adjustment step 22. In calculation step 24, the amount of fuel supplied is calculated based on the specifications of the fuel cell utilization factor of the fuel cell device 10. In calculation step 24, a volume flow of the amount of fuel supplied is determined. In operating step 18, a volume flow of fuel determined in a calculation step 24 is supplied.

[0033] In at least one operating step 18, the level of the volume flow is influenced by the selection of the fuel cell utilization factor of the fuel cell unit 12. In the operating step 18, a low fuel cell utilization factor of the fuel cell unit 12 (FU Stack) a high volume flow is generated. In operating step 18, a high volume flow is generated in the recirculation stream 20 with a low fuel cell utilization rate of the fuel cell unit 12. In operating step 18, a high volume flow is generated in the fuel cell unit 12 with a low fuel cell utilization rate of the fuel cell unit 12. In operating step 18, the volume flow upstream of a fuel cell unit 12 is equal to a volume flow downstream of the fuel cell unit 12. In operating step 18, the composition of the volume flow upstream of a fuel cell unit 12 changes to the volume flow downstream of the fuel cell unit 12. In operating step 18, the hydrogen content of the volume flow upstream of a fuel cell unit 12 changes to the hydrogen content of the volume flow downstream of the fuel cell unit 12. In operating step 18, the volume flow level is determined using the formula: n˙Stack,IN=Iel∗Ncell2F∗xH2∗FUStack calculated. In operating step 18, the amount of hydrogen supplied corresponds to the same amount of condensed water.

Claims

[1] A method for operating a fuel cell device (10), in particular a hydrogen-powered SOFC fuel cell device, which has at least one fuel cell unit (12), in particular a fuel cell stack, at least one blower unit (14), at least one heat transfer unit (30), in particular a condensation heat transfer unit, and at least one control and regulating unit (16), with an operating step (18) in which the fuel cell unit (12) obtains electrical energy from a gaseous medium, wherein the blower unit (14) regulates and drives a recirculation circuit (20) in the operating step (18), and wherein an operation of the fuel cell device (10) is regulated by means of the control and regulating unit (16) in the operating step (18), characterized byin that in at least one adaptation step (22) a fuel cell utilization factor of the fuel cell unit (12) is adapted, in particular reduced, wherein in parallel the fuel cell utilization factor of the fuel cell device (10) is kept constant. [2] Method according to claim 1, characterized by in that in the at least one adaptation step (22) the control and regulating unit (16) regulates a blower unit (14) in order to reduce the fuel cell utilization factor of the fuel cell unit (12). [3] Method according to claim 1 or 2, characterized by that in the at least one adaptation step (22) by means of the heat transfer unit (30), in particular condensation heat transfer unit, a fuel cell utilization factor of the fuel cell unit (12) is adapted. [4] Method according to one of the preceding claims, characterized bythat in at least one operating step (18) a cell voltage of the fuel cell unit (12) is increased by the adaptation of the fuel cell utilization factor of the fuel cell unit (12) carried out in the adaptation step (22). [5] Method according to one of the preceding claims, characterized by that in at least one calculation step (24) a quantity of the supplied fuel is determined on the basis of the specifications of the fuel cell utilization rate of the fuel cell device (10). [6] Method according to one of the preceding claims, characterized by that in at least one operating step (18) the level of the volume flow is influenced by the selection of the fuel cell utilization factor of the fuel cell unit (12). [7] Fuel cell device (10), in particular a hydrogen-powered SOFC fuel cell device, for carrying out a method according to one of the preceding claims.

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