Fuel cell system and method for providing electrical energy

Abstract

The present invention relates to a fuel cell system (100) for providing electrical energy. SOLUTION: The fuel cell system (100) includes a blower (101) for pumping an anode gas, a motion sensor (103) for determining a measured value of the motion of an impeller of the blower (101), and a control unit (105). The control unit (105) is configured to assign, using a predetermined assignment scheme, a state of material composition in an anode circuit of the fuel cell system (100) to the measured value determined by the motion sensor (103) within a rotational speed range between a start rotational speed and a predetermined target rotational speed, and to adjust the fuel cell system (100) in accordance with the assigned state.

Description

[Technical Field]

[0001] The present invention relates to fuel cell systems and methods for providing electrical energy. [Background technology]

[0002] Hydrogen-based fuel cells are seen as the mobility concept of the future, as they only produce water as an off-gas and allow for fast refuelling.

[0003] Some of the water produced on the cathode side of the fuel cell when hydrogen reacts with air diffuses through the membrane to the anode side, where it mixes with fresh hydrogen. Similarly, nitrogen, a component of air, is transported from the cathode to the anode. This results in a gas mixture or composition of matter on the anode side consisting of hydrogen, nitrogen, and water during operation.

[0004] To ensure an adequate supply of hydrogen to the fuel cells in a fuel cell system, hydrogen is typically provided in stoichiometric excess. To improve efficiency and reduce hydrogen losses, the anode off-gas is typically directed back in a recirculation circuit and mixed with fresh hydrogen.

[0005] To remove the undesirable species nitrogen and water, the anode circuit of a fuel cell system is periodically purged. For this purpose, a scavenging valve, or so-called "purge valve," is opened while an increased amount of fresh hydrogen is supplied. However, such scavenging processes are generally not performed selectively, and therefore hydrogen is also discharged.

[0006] Various topologies are known for the configuration of the anode circuit, in which the pressure gradient creating the recirculating flow is generated by an active blower, e.g. a compressor, and / or passively by an ejector, i.e. a so-called "jet pump".

[0007] When a fuel cell system is started, the anode circuit is first filled with fresh hydrogen while the respective cathode shutoff valves are still closed. This is known as "flushing." During the flush, only the oxygen still available in each fuel cell is converted. At the same time, the nitrogen and water present in the anode circuit are removed from the anode circuit by opening the scavenge valves.

[0008] Efforts are made to limit the duration of the scavenging process to the minimum necessary, since otherwise there is a risk that the hydrogen released by the scavenging process will form an explosive mixture in the off-gas path of the fuel cell system. To prevent this, an air compressor or blower is typically operated to dilute the outgoing hydrogen to a non-explosive level.

[0009] However, the problem is that, due to limited construction space in the vehicle, there is usually no possibility to directly measure the hydrogen concentration in the anode circuit. Summary of the Invention [Problem to be solved by the invention]

[0010] Within the scope of the present invention, a fuel cell system and a method for operating a fuel cell system are presented. Further features and details of the invention can be seen from the respective dependent claims, the description and the drawings. It is clear that the features and details explained in the context of the fuel cell system according to the invention also apply in the context of the method according to the invention and vice versa, so that reference is or can always be made to each other in the disclosure of the individual inventive aspects.

[0011] The invention presented is particularly useful for the efficient provision of electrical energy by fuel cell systems, and more particularly for the efficient operation of vehicles. [Means for solving the problem]

[0012] Thus, according to a first aspect of the present invention, a fuel cell system for providing electrical energy is presented, which comprises a blower for pumping an anode gas, a motion sensor for measuring the motion of the blower, and a control unit, which is configured to assign, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system to a measured value determined by the motion sensor within a speed range between a starting speed, in particular zero, and a predetermined target speed, and to adjust the fuel cell system in accordance with the assigned state.

[0013] By blower, in the context of the present invention, is to be understood a mechanism for pumping air, such as a compressor, which has a drive and a rotatable impeller.

[0014] Target speed is to be understood in the context of the present invention as a predetermined speed for the operation of the fan.

[0015] The state of a substance composition in the context of the present invention is to be understood as the concentration distribution and / or aggregation state of the substances in the substance composition. Correspondingly, the state of substance concentration refers to the chemical and / or physical state of the substance concentration.

[0016] By state of the fan is to be understood in the context of the present invention, for example, the rotational speed and / or momentum of the fan impeller within a given time window.

[0017] An allocation scheme is to be understood in the context of the present invention as an allocation table, in particular an allocation table which assigns a respective state to each measured value or is configured to assign a respective state to each measured value.

[0018] By anode gas, in the context of the present invention, is to be understood the gas, for example a hydrogen-nitrogen-water mixture, that flows within the anode subsystem of the fuel cell system.

[0019] In the context of the present invention, a movement sensor is to be understood as a sensor, in particular a combination sensor, which determines a variable that can be evaluated for the movement of the fan provided according to the invention, whereby the variables can be understood as rotational speed, acceleration, moment, jerk and / or current supplied to the fan motor.

[0020] The present invention is based on the principle that the resistance of the impeller of a blower arranged in the anode circuit of a fuel cell system during a change in rotation speed, in particular during the ramp-up period after starting, varies depending on the state of the substance composition in the corresponding anode circuit of the fuel cell system. Correspondingly, the speed profile of the blower and / or the torque profile driving the blower during a change in rotation speed, for example during the ramp-up period, in particular during the start-up process of the fuel cell system or the start-up process, varies depending on the respective substances and their concentrations present in the anode circuit, i.e., the state of the substance composition present.

[0021] Hydrogen is a low density gas and therefore exhibits a particularly low mechanical resistance, whereas nitrogen is significantly denser than hydrogen and exhibits a correspondingly higher mechanical resistance, a particularly high mechanical resistance being exhibited by water, especially frozen water.

[0022] Based on the interaction between the mechanical resistance caused by the respective substances and their concentrations in the anode circuit and the speed profile of the blower operating in the anode circuit, the state of the substance composition in the anode circuit, in particular the hydrogen concentration, can be estimated based on characteristic variables in the speed profile and / or momentum profile of the blower.

[0023] As soon as the current state of the material composition in the anode circuit of the respective fuel cell system is known, the fuel cell system can be adjusted to the current state, for example by lengthening or shortening the duration of the scavenging process relative to a base value or by selecting it depending on, for example, the nitrogen concentration in the anode circuit. Correspondingly, the duration of the scavenging process can be dynamically adjusted and does not have to be designed for a maximum nitrogen concentration, as is common in the prior art. Due to the dynamically adapted duration of the scavenging process, hydrogen leakage is minimized and the efficiency of the fuel cell system is maximized.

[0024] The control unit may be configured to determine first and second order gradients of the measured values determined in the rotational speed range, and the assignment scheme may further assign to each value of the first and second order gradients a corresponding concentration value of hydrogen and / or water and / or nitrogen in the anode circuit.

[0025] On the basis of the gradients of different orders, characteristic regions in the measured values, in particular in the speed curve and / or torque curve, such as rises or falls, can be displayed in a compressed form. In particular, by matching gradients of different orders with the assignment scheme provided according to the invention, a reliable discrimination or identification of different states or different material compositions can be carried out.

[0026] The assignment scheme may assign the state "low hydrogen concentration" to each determined measurement value when the slope of the first-order measurement value is above a predetermined first slope threshold and the slope of the second-order measurement value is below a predetermined second slope threshold, and the assignment scheme may assign the state "medium hydrogen concentration" to each determined measurement value when the slope of the second-order measurement value is less than zero and more negative than a predetermined negative threshold within a speed range around 50% of the target speed, and the assignment scheme may assign the state "low hydrogen concentration" to each determined measurement value when the slope of the second-order measurement value is less negative than the negative threshold within a speed range around 50% of the target speed. In the case of high hydrogen concentrations in the anode circuit, for example above 80 vol.%, the speed trajectory of the fan of the fuel cell system is approximately linear and the target speed is reached after a few seconds. As a result, in this case, the first-order gradient reaches a maximum value, and the second-order gradient, i.e., the change in inclination, exhibits only small values up to the vicinity of the target rotation speed.

[0027] The threshold values provided in the proposed inventive configuration can be configured as positive or negative depending on the measured value sought, so that it is possible to map, for example, the behavior of the torque value inversely to the rotational speed value.

[0028] Therefore, the assignment scheme may assign the state "low hydrogen concentration" to each determined rotational speed value when the gradient of the first order of the rotational speed value is above a predetermined first gradient threshold and the gradient of the second order of the rotational speed value is below a predetermined second gradient threshold, and the assignment scheme may assign the state "medium hydrogen concentration" to each determined rotational speed value when the gradient of the second order of the rotational speed value takes a negative value less than zero and more than a predetermined negative threshold within a rotational speed range around 50% of the target rotational speed, and the assignment scheme may assign the state "low hydrogen concentration" to each determined rotational speed value when the gradient of the second order of the rotational speed value takes a negative value less than the negative threshold within a rotational speed range around 50% of the target rotational speed.

[0029] Alternatively or additionally, the assignment scheme may assign the state "low hydrogen concentration" to each determined moment value when the first-order slope of the moment value is below a predetermined first slope threshold and the second-order slope of the moment value is above a predetermined second slope threshold, and the assignment scheme may assign the state "medium hydrogen concentration" to each determined moment value when the second-order slope of the moment value is greater than zero and less negative than a predetermined negative threshold within a moment region around 50% of the target moment, and the assignment scheme may assign the state "low hydrogen concentration" to each determined moment value when the second-order slope of the moment value is less negative than a negative threshold within a moment region around 50% of the target moment.

[0030] In the case of high hydrogen concentrations in the anode circuit, for example above 80 vol.%, the speed trajectory of the fan of the fuel cell system is approximately linear and the target speed is reached after a few seconds, so that in this case the first-order gradient reaches a maximum value and the second-order gradient, i.e. the change in slope, shows only small values up to the target speed.

[0031] In the case of a medium hydrogen concentration, for example 50 to 70 vol.%, the rotational speed trajectory of the blower of the fuel cell system has a bend in the region exceeding 50% of the target rotational speed, and as a result, the rotational speed trajectory or rotational speed progression becomes flatter and the second-order gradient becomes negative.

[0032] In the case of low hydrogen concentrations, e.g., 0-50 vol.%, the rotational speed trajectory of the fan of the fuel cell system exhibits a strong inflection above approximately 50% of the target rotational speed, resulting in a more negative second-order gradient. At the same time, a step increase in rotational speed occurs during each scavenging process, resulting in a short-term positive second-order gradient.

[0033] Furthermore, the control unit may be configured to control the operation of a scavenge valve of the fuel cell system in response to the determined state of matter composition.

[0034] By controlling the operation of the scavenging valve in response to the desired state of material composition in the anode circuit of the fuel cell system, the scavenging valve can be dynamically controlled, so that unnecessary leakage of hydrogen is minimized and the efficiency of the fuel cell system is maximized.

[0035] Furthermore, the allocation scheme may be configured to allocate water in the anode circuit to the determined measurements when the value of the first order gradient of the determined measurements varies between positive and negative values, and the control unit may be configured to control the operation of the scavenging valve such that the scavenging valve periodically opens and closes for cases in which the allocation scheme allocates water in the anode circuit to each determined measurement.

[0036] By periodically or pulse-wise opening and closing the scavenging valve, for example, in a period of a few seconds, in particular 1 to 10 seconds, preferably 3 to 5 seconds, the water can be particularly well removed from the fuel cell system, since the cyclical opening and closing of the valve drives the water towards the scavenging valve. During the cyclical opening and closing, the scavenging valve is, for example, repeatedly opened for a predetermined duration and closed again for a short intermediate phase of similar duration.

[0037] Furthermore, the allocation scheme may allocate water in the anode circuit to the determined measured values when the value of the first order gradient of the determined measured values varies between positive and negative values, and the control unit may be configured to control the operation of the scavenging valve such that the scavenging valve periodically opens and closes for cases in which the allocation scheme allocates water to the anode circuit for each determined measured value.

[0038] Therefore, the allocation scheme may allocate water in the anode circuit to the determined rotational speed values when the value of the first-order gradient of the determined rotational speed values varies between positive and negative values, and the control unit may be configured to control the operation of the scavenging valves so that they periodically open and close for the cases in which the allocation scheme allocates water to the anode circuit for each determined rotational speed value.

[0039] Alternatively or additionally, the allocation scheme may allocate water in the anode circuit to the determined moment values when the value of the first order gradient of the determined moment values varies between negative and positive values, and the control unit may be configured to control the operation of the scavenging valves such that the scavenging valves periodically open and close for cases in which the allocation scheme allocates water to the anode circuit for each determined moment value.

[0040] A low hydrogen concentration in the anode circuit of a fuel cell system means that nitrogen has accumulated in the anode circuit. The increased density of nitrogen causes the speed of the blower operating in the anode circuit to increase more slowly than when the hydrogen concentration is high. This means that the first-order slope of the measurement taken at the start of the blower rotation is below a predetermined threshold. However, the first-order slope exceeds the threshold when water is present in the anode circuit.

[0041] Furthermore, above 50% of the target speed of each fan, a bend in the speed trajectory occurs, resulting in a short-term negative second-order gradient. In this case, the scavenging valve is continuously opened and remains open at least until the fan reaches its target speed. In this region, the hydrogen concentration is typically above 70 vol.%, which is sufficient for a reliable start of the fuel cell system.

[0042] Furthermore, the control unit may be configured to continuously open the scavenging valve until the target speed of the blower is reached when the allocation scheme assigns a low hydrogen concentration in the anode circuit to the determined measured value.

[0043] By continuously opening the scavenging valve, high nitrogen concentrations can be reduced efficiently and accordingly problem-free operation of the fuel cell system can be enabled.

[0044] Furthermore, the movement sensor may be a rotational speed sensor and / or a moment sensor, for example a current sensor that determines the current flowing towards the fan, i.e. the current taken up by the fan.

[0045] A moment sensor, i.e. a sensor for determining momentum, in particular a sensor for determining current intensity, on the impeller of the fan provided according to the invention has proven to be particularly advantageous for determining the moment progression or moment trajectory of the fan of a fuel cell system.

[0046] By way of example, the moment sensor may be integrated into the fan provided according to the invention or may be configured as an additional or external moment sensor relative to the fan.

[0047] Based on the analysis of the first and second order gradients of the signal determined by the moment sensor and the time taken for the signal determined by the moment sensor to reach its maximum value during the speed jump or during the ramp-up, especially the initial ramp-up, of the fan, the hydrogen concentration at the start of the speed jump can be estimated and / or the arrival of the target speed can be detected. Alternatively or additionally, the hydrogen concentration can be estimated by analyzing the signal determined by the moment sensor after the maximum value has been passed.

[0048] Furthermore, the assignment scheme may be such that the determined measurement value is assigned the status "frozen scavenge valve" when the value of the second order gradient of the determined measurement value is below a predetermined scavenge threshold value after the scavenge process.

[0049] Therefore, the assignment scheme may be such that the determined speed value is assigned the status "frozen scavenge valve" when the value of the second order gradient of the determined speed value is below a predetermined scavenge threshold value after the scavenge process.

[0050] Alternatively or additionally, the assignment scheme may assign the state "frozen scavenge valve" to the determined moment value when the value of the second order gradient of the determined moment value is above a predetermined scavenge threshold after the scavenge process.

[0051] If the blower speed increases stepwise during each scavenging process, this is usually due to the flow of fresh hydrogen into the anode circuit due to the scavenging process. This is because the density of the medium circulating in the anode circuit decreases, and the blower has to overcome less flow resistance. The operation of the hydrogen valve supplying hydrogen to the anode circuit is usually controlled by pressure, so that the target pressure in the anode circuit is adjusted or maintained by opening the hydrogen valve. If the scavenging valve is frozen, no pressure drop occurs when the scavenging valve opens, which is compensated for by the supply of fresh hydrogen. As a result, no hydrogen is supplied during the scavenging process, and the blower speed does not increase stepwise, which can be recognized by a second-order gradient change in the blower speed. If a second-order gradient increase in the blower speed does not occur directly during the scavenging process, one must conclude that the scavenging valve is frozen.

[0052] In a second aspect, the present invention provides a method for operating a fuel cell system, the method comprising: a determining step of determining, by a motion sensor, measured values of a blower of the fuel cell system for pumping anode gas within a speed range between a starting speed and a predetermined target speed; an assigning step of assigning the measured values determined by the motion sensor within the speed range to states of material composition in an anode circuit of the fuel cell system using a predetermined assignment scheme; and an adjusting step of adjusting the fuel cell system in accordance with the states assigned in the assigning step.

[0053] The methods presented are particularly useful for operating the fuel cell systems presented.

[0054] The adjusting step may include controlling the operation of a scavenging valve of the fuel cell system.

[0055] Further advantages, features and details of the invention can be seen from the following description, in which an embodiment of the invention is explained in detail with reference to the drawings, in which it is to be noted that each of the features mentioned in the claims and in the description may be essential to the invention, either alone in itself or in any combination. [Brief explanation of the drawings]

[0056] [Figure 1] 1 shows a schematic structure of one possible configuration of a fuel cell system according to the present invention; [Figure 2] 3 shows various curves of the fan speed signal of one possible configuration of the fuel cell system according to the invention; [Figure 3] 1 is a schematic diagram of one possible configuration of the method according to the invention; DETAILED DESCRIPTION OF THE INVENTION

[0057] 1 shows a fuel cell system 100. The fuel cell system 100 includes a blower 101 for pumping anode gas, a motion sensor 103 for obtaining a measurement of the motion of the impeller of the blower 101, and a control unit 105.

[0058] The control unit 105 is configured to assign, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system 100 to a measured value of the blower 101 determined by the motion sensor 103 within a speed range between a starting speed, in particular zero, and a predetermined target speed, and to adjust the fuel cell system 100 in accordance with the assigned state.

[0059] To regulate the fuel cell system 100, the control unit 105 can, for example, open or close the scavenging valve 107 of the fuel cell system 100, thereby changing the state of the substance composition in the anode circuit. In particular, the control unit 105 can dynamically change the duration for which the scavenging valve 107 is open, depending on the state assigned to each determined measured value by the allocation scheme. The measured value determined by the motion sensor 103 can be the rotational speed value of the impeller of the blower and / or the moment value of the momentum required to move the impeller. Accordingly, the measured value determined by the motion sensor 103 depends on the forces acting on the impeller, in particular the resistance of the gas to be moved by the impeller. Since the density of the gas, and therefore the resistance of the gas, varies depending on the concentration of the respective components, in particular hydrogen, the concentration of the respective components of the gas being moved by the impeller can be estimated based on the measured values. In this case, the moment value and / or the rotational speed value, in particular during acceleration and / or braking of the impeller, can be characteristic variables for determining the concentration of the respective components of the gas. Correspondingly, the slope of the second and / or third grade of change in the measured value may be used to identify the concentration of the respective component of the gas.

[0060] FIG. 2 shows graphs 201, 203 and 205, each of which has time on the abscissa axis and the rotational speed of a blower operating in the anode circuit of a fuel cell system on the ordinate axis.

[0061] Transitions 207, 209 and 211 show the change in hydrogen concentration in the anode circuit.

[0062] Transitions 213, 215 and 217 show the operation of the scavenging valves.

[0063] The progressions 219, 221 and 223 show progressions of the measured values of the motion sensors, for example progressions of the number of revolutions of a fan.

[0064] The progression 225 is the same for graphs 201, 203 and 205 and represents the predetermined RPM target value for the fan.

[0065] Comparing graphs 201, 203, and 205, it can be seen that at low hydrogen concentrations, as shown in curve 207, a rapid increase in the rotational speed is first achieved up to approximately 50% of the target rotational speed, followed by a slower increase, as shown in curve 219. Therefore, curve 219 exhibits a strong inflection at 50% of the target rotational speed, resulting in a strongly negative second-order slope at this point. At the same time, it can be observed that a speed step occurs with each scavenging process, and that during this speed step, the second-order slope of curve 219 is briefly positive.

[0066] At medium hydrogen concentration, as shown in transition 209, the rotational speed transition 221 has a bend in the region above 50% of the target rotational speed, resulting in the transition 221 becoming flatter and the second-order slope of the transition 221 becoming negative.

[0067] At high hydrogen concentrations, as shown in the curve 211, a nearly linear rotational speed curve 223 occurs, and the target rotational speed is reached after a few seconds. As a result, in this case, the first-order gradient of the curve 223 reaches a maximum value, and the second-order gradient of the curve 223 only exhibits small values up to the target rotational speed.

[0068] Furthermore, comparing the graphs 201, 203 and 205, it can be seen that depending on the hydrogen concentration present or the water content in the anode circuit, clearly different profiles 225, 227 and 229 of the current drawn by the blower occur.

[0069] Upon reaching the target speed at point 231, the current curve 225 exhibits a significant inflection. This inflection can thus be associated with the end of the fan acceleration process. At the same time, it becomes clear that the current curve assumes different steady-state values after reaching the target speed depending on the respective hydrogen concentrations present. This results from the fact that different hydrogen concentrations lead to different densities and thus different resistances for the fan. Thus, analysis of the current curve during ramp-up can be used to determine the hydrogen concentration at the start and as a result of the scavenging process. Correspondingly, the hydrogen concentration present after the speed jump can be estimated based on the steady-state value after the speed jump.

[0070] 3 shows a method 300 for operating a fuel cell system. The method 300 includes a determining step 301 in which a motion sensor measures the motion of an impeller of a blower that pumps anode gas in the fuel cell system within a speed range between a starting speed, in particular zero, and a predetermined target speed, an assigning step 303 in which the measured values measured by the motion sensor within this speed range are assigned to states of material composition in the anode circuit of the fuel cell system using a predetermined assignment scheme, and an adjusting step 305 in which the fuel cell system is adjusted in accordance with the states assigned in the assigning step. [Explanation of symbols]

[0071] 100 Fuel Cell System 101 Blower 103 Motion Sensor 105 Control Unit 107 Scavenging valve 201 graphs 203 graphs 205 graphs 207 Transition, change in hydrogen concentration in the anode circuit 209 Transition, change in hydrogen concentration in the anode circuit 211 Transition, change in hydrogen concentration in the anode circuit 213 Transition, scavenging valve operation 215 Transition, scavenging valve operation 217 Transition, scavenging valve operation 219 Transition, Motion Sensor Measurements, Fan RPM 221 Transition, motion sensor readings, fan rotation speed 223 Transition, motion sensor readings, fan rotation speed 225 Transition, the predetermined speed target of the fan, the current drawn by the fan 227 Transition, current drawn by the blower 229 Transition, current drawn by the blower 231 points, target rotation speed reached 300 Method for operating a fuel cell system 301 Search Step 303 Allocation Step 305 Adjustment Steps

Claims

1. A fuel cell system (100) for providing electrical energy, comprising: The fuel cell system (100) a blower (101) for pumping the anode gas; a movement sensor (103) for determining a measurement of the movement of the impeller of said fan (101); a control unit (105), Equipped with The control unit (105) assigning, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system to a measured value of the blower (101) determined by the motion sensor (103) within a rotational speed range between a start rotational speed and a predetermined target rotational speed, and adjusting the fuel cell system (100) in accordance with the assigned state; It is composed of the control unit (105) is configured to control the operation of a scavenging valve (107) of the fuel cell system (100) in response to a determined state of matter composition; A fuel cell system (100) for providing electrical energy.

2. A fuel cell system (100) for providing electrical energy, comprising: The fuel cell system (100) a blower (101) for pumping the anode gas; a movement sensor (103) for determining a measurement of the movement of the impeller of said fan (101); a control unit (105), Equipped with The control unit (105) assigning, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system to a measured value of the blower (101) determined by the motion sensor (103) within a rotational speed range between a start rotational speed and a predetermined target rotational speed, and adjusting the fuel cell system (100) in accordance with the assigned state; It is composed of the control unit (105) is configured to determine first and second order gradients of the measured values determined within the rotational speed range; and the allocation scheme assigns to each value of the first and second order gradients a corresponding concentration value of hydrogen and / or water and / or nitrogen in the anode circuit; A fuel cell system (100) for providing electrical energy.

3. the assignment scheme assigns a status "low hydrogen concentration" to each determined measurement when the first-order slope of the measurement is above a predetermined first slope threshold and the second-order slope of the measurement is below a predetermined second slope threshold; and the assignment scheme assigns the state "medium hydrogen concentration" to each determined measurement when the second order gradient of the measurement is less than zero and more negative than a predetermined negative threshold within a speed range around 50% of the target speed; and the assignment scheme assigns the status "low hydrogen concentration" to each determined measurement when the second order gradient of the measurement takes a negative value less than the negative threshold value within the rotational speed range around 50% of the target rotational speed; The fuel cell system (100) of claim 2.

4. 4. The fuel cell system (100) according to claim 2 or 3, characterized in that the control unit (105) is configured to control the operation of a scavenging valve (107) of the fuel cell system (100) depending on the desired state of material composition.

5. 2. The fuel cell system (100) according to claim 1, characterized in that the assignment scheme assigns the state "water in the anode circuit" to the determined measurement value when the value of the first-order gradient of the determined measurement value varies between positive and negative values, and the control unit (105) is configured to control the operation of the scavenging valve (107) so that the scavenging valve (107) is periodically opened and closed for cases in which the assignment scheme assigns water in the anode circuit to the respective determined measurement value.

6. 2. The fuel cell system (100) according to claim 1, wherein the control unit (105) is configured to continuously open the scavenging valve (107) until the target rotation speed of the blower (101) is reached when the allocation scheme allocates a low hydrogen concentration in the anode circuit to the determined measured value.

7. 4. The fuel cell system (100) according to claim 2 or 3, characterized in that the motion sensor (103) is a rotational speed sensor and / or a moment sensor for determining the momentum of the blower, in particular a current sensor for determining the current flowing towards the blower (101).

8. A fuel cell system (100) for providing electrical energy, comprising: The fuel cell system (100) a blower (101) for pumping the anode gas; a movement sensor (103) for determining a measurement of the movement of the impeller of said fan (101); a control unit (105), Equipped with The control unit (105) assigning, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system to a measured value of the blower (101) determined by the motion sensor (103) within a rotational speed range between a start rotational speed and a predetermined target rotational speed, and adjusting the fuel cell system (100) in accordance with the assigned state; It is composed of the motion sensor (103) is a rotational speed sensor and / or a moment sensor for determining the momentum of the blower, in particular a current sensor for determining the current flowing towards the blower (101); A fuel cell system (100) for providing electrical energy.

9. 4. The fuel cell system (100) according to claim 2 or 3, characterized in that the assignment scheme assigns the determined measurement value to the state "frozen scavenge valve" when the value of the second-order gradient of the determined measurement value is below a predetermined scavenge threshold after the scavenge process.

10. A fuel cell system (100) for providing electrical energy, comprising: The fuel cell system (100) a blower (101) for pumping the anode gas; a movement sensor (103) for determining a measurement of the movement of the impeller of said fan (101); a control unit (105), Equipped with The control unit (105) assigning, using a predetermined assignment scheme, a state of material composition in the anode circuit of the fuel cell system to a measured value of the blower (101) determined by the motion sensor (103) within a rotational speed range between a start rotational speed and a predetermined target rotational speed, and adjusting the fuel cell system (100) in accordance with the assigned state; It is composed of - the assignment scheme assigns the determined measurement value to the status "frozen scavenge valve" when the value of the second order gradient of the determined measurement value is below a predetermined scavenge threshold value after a scavenge process; A fuel cell system (100) for providing electrical energy.

11. A method (300) of operating a fuel cell system (100), comprising: The method (300) comprises: a determining step (301) for determining, by a motion sensor (103), a measurement value of the motion of an impeller of a blower (101) of the fuel cell system (100) for pumping an anode gas within a rotational speed range between a start rotational speed and a predetermined target rotational speed; an assignment step (303) of assigning the measurements determined by the motion sensor (103) within the rotational speed range to a state of material composition in the anode circuit of the fuel cell system (100) using a predetermined assignment scheme; an adjusting step (305) of adjusting the fuel cell system (100) according to the state assigned in the assigning step (303); Including, A method (300) of operating a fuel cell system (100).

12. The method (300) of claim 11, wherein the adjusting (305) step comprises controlling the operation of a scavenge valve (107) of the fuel cell system (100).

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