Method for operating a fuel cell electric vehicle and fuel cell electric vehicle

Abstract

The invention relates to a method for operating a fuel cell electric vehicle (2) with an electric drive system (14), with at least one battery (10), with a fuel cell system (4) comprising at least one fuel cell (6) in which electrical energy can be generated and supplied to the battery (10) and / or the electric drive system (14), and with at least one control unit (18) by which at least the electric drive system (14), the battery (10) and the fuel cell system (4) can be controlled.

Description

The invention relates to a method for operating a fuel cell electric vehicle and a fuel cell electric vehicle that can be operated according to such a method. Fuel cell electric vehicles are known in various designs from the state of the art. To achieve an extended range, these vehicles include a high-voltage battery, which serves as the primary energy source. A fuel cell provides additional charging energy for the battery, thus increasing the range compared to a "pure" battery electric vehicle. Such concepts can also include so-called "low-power" designs, in which the battery is the primary energy source and the fuel cell makes a minor contribution. Current technology includes so-called "full-power concepts" in which the fuel cell serves as the primary energy source and is operated dynamically. These electric vehicles incorporate a small high-voltage battery to provide support during transient driving maneuvers. However, fuel cells achieve their highest efficiency in stationary operation, which is comparatively lower in dynamic operation. Between the two previously mentioned options there is a so-called "mid-power concept" that forms a compromise between both. Medium-power concepts have the disadvantage that the fuel cell alone is unable to meet high traction requirements, which can arise, for example, from a combination of heavy payload, steep uphill climbs, and / or high vehicle speeds. A battery must compensate for this power gap. This proves particularly critical if the battery cannot be discharged due to thermal limitations or a low state of charge and therefore cannot contribute to supporting the traction requirements. Predictive energy management methods are known from the prior art, in which the energy and fuel consumption of the anticipated journey from a starting node to an end node is calculated using weighted diagrams. The journey is segmented into individual sections, and the various possibilities for hydrogen consumption from the beginning to the end of each section are determined. The options available are always that the fuel cell is operated in such a way that it charges the battery, the battery maintains its current charge level, or the battery is discharged. This results in three possible routes from each starting node to the end of the respective section. Considering the entire journey, this yields a very large number of possibilities.A control unit then calculates the most energy-efficient or fuel-efficient route. Due to the large number of calculation steps, a high memory requirement is necessary and determining the most favorable path is very computationally intensive. One object of an embodiment of the invention is to propose a method for operating a fuel cell electric vehicle and a fuel cell electric vehicle that can be operated according to such a method, in which the storage requirement and the computing time for determining an optimal operation can be reduced. This problem is solved by a method for operating a fuel cell electric vehicle with an electric drive system, with at least one battery, with a fuel cell system comprising at least one fuel cell in which electrical energy can be generated and supplied to the battery and / or the electric drive system, and with at least one control unit by which at least the electric drive system, the battery, and the fuel cell system can be controlled, comprising the steps: a. 100: Recording all sections of the journey, recording the energy demand of the drive system in the sections of the journey, and combining all sections into a single route segment; b. 101: Determining a total electrical energy demand for the entire journey; c. 102: Determining a usable battery energy window for charging and discharging the battery for each section of the route segment.103: Determining a constant fuel cell cycle power over the route segment to provide the total electrical energy demand; e. 104: Determining a delta at each point of the route segment, formed from the difference between the energy demand of the propulsion system on the one hand and the sum of the energy provided by the fuel cell cycle power and the maximum usable battery energy window on the other, wherein a critical delta is detected in the route segment if the delta at at least one point of the route segment is positive when the battery is discharging or negative when the battery is charging, and wherein a non-critical delta is detected in all other cases, and i. operating the fuel cell system at the determined fuel cell cycle power over the entire journey if the delta at each point of the route segment is non-critical; or ii.Performing fuel cell operation optimization to determine route segment-dependent cycle powers of the fuel cell with which the fuel cell is operated constantly in different route segments when the delta is critical at least at one point of the route segment. Due to the initial assumption chosen here that the route segment encompasses the entire journey, and the assumption that the fuel cell contributes a constant cycle power to the total electrical energy requirement for the entire journey over the route segment (i.e., in the initial assumption, the entire journey), all journeys in which the delta is non-critical at every point of the route segment can be modeled quickly and with little computational effort. If necessary, specifically if the delta is critical at at least one point in the route segment (i.e., the entire journey in the initial assumption), the calculation can be intensified during fuel cell operation optimization. This provides an algorithm that requires fewer memory resources and less computational effort compared to the state of the art while achieving similar results. This allows the method to be applied to current vehicles and even transferred to older vehicle architectures that have fewer memory resources and less computing capacity than current vehicles. In comparison to the previously mentioned method of calculation using weighted diagrams, this provides an alternative solution that reduces storage and computational effort. The usable battery energy window for charging may differ in amount from the usable battery energy window for discharging the battery for each section of the route segment. When calculating the sum of the energy provided by the fuel cell's cycle power and the maximum usable battery energy window, the amount of the usable battery energy window for discharging the battery is added to the energy provided by the fuel cell's cycle power when discharging the battery in the route segment, and the amount of the usable battery energy window for charging the battery is subtracted from the energy provided by the fuel cell's cycle power when charging the battery in the route segment. If the critical delta is positive at at least one point in the route segment, the energy provided by the fuel cell together with the energy provided by the battery is insufficient to meet the energy requirements of the drive system. If the critical delta is negative at at least one point in the route segment, the battery will continue to be charged with electrical energy at that point, even though the battery has already reached its maximum state of charge. The total electrical energy consumption for the entire journey includes the energy required by the powertrain to complete the journey. In some embodiments of the method, additional electrical energy consumption by auxiliary units, such as seat heating, media devices, air conditioning units, etc., can also be recorded. The method according to the invention makes it possible to operate the fuel cell at a constant power output in the route segment, minimizing fuel cell consumption while simultaneously protecting the battery against overcharging and complete discharge. This results in optimal fuel cell efficiency. The present method can be applied in particular to so-called "mid-power concepts". However, the method can also be applied to so-called "full-power concepts" and "range-extender concepts". If a critical delta is detected at any point in the route segment, i.e., if the delta is positive at at least one point in the route segment when the battery is discharged or negative when the battery is charged, and this necessitates performing fuel cell operation optimization according to step 104 ii., it is advantageous if the fuel cell operation optimization comprises the following iterative feasible steps for each route segment that includes at least one critical delta at any point: a. 200: Identifying the position of the point of the largest critical delta in the route segment and detecting the magnitude of the largest critical delta; b. 201: Dividing the route segment into a pre-route segment, which includes all driving sections before the point of the largest critical delta, and a post-route segment, which includes all driving sections after the point of the largest critical delta; c.202: Determine a constant pre-cycle power of the fuel cell for the pre-route segment such that the delta at the location of the previous largest critical delta is zero; d. 203: Determine a constant post-cycle power of the fuel cell for the post-route segment from the total electrical energy demand subtracted from the sum of the energy provided by the pre-cycle power of the fuel cell; e.204: Capturing a pre-delta at each point of the pre-route segment, formed from the difference between the energy demand of the propulsion system at each point of the pre-route segment on the one hand and the sum of the energy provided by the pre-cycle power of the fuel cell and the usable battery energy window at the same point on the other hand; and capturing a post-delta at each point of the post-route segment, formed from the difference between the energy demand of the propulsion system at the same point on the one hand and the sum of the energy provided by the post-cycle power of the fuel cell and the usable battery energy window at each point of the post-route segment on the other hand; f.205: Constant operation of the fuel cell system with the determined pre-cycle power of the fuel cell in the pre-route segment, if the pre-delta is non-critical at every point of the pre-route segment and / or constant operation of the fuel cell system with the determined post-cycle power of the fuel cell in the post-route segment, if the post-delta is non-critical at every point of the post-route segment; or g.206: Equating the pre-route segment with the route segment, the pre-delta with the delta, and the total energy with the energy provided by the pre-cycle power of the fuel cell, and proceeding through steps 200 to 205 if the pre-delta is critical for driving at least at one point in the pre-route segment, and / or equating the post-route segment with the route segment, the post-delta with the delta, and the total energy with the energy provided by the post-cycle power of the fuel cell, and proceeding through steps 200 to 205 if the post-delta is critical for driving at least at one point in the post-route segment. By dividing the section of road under investigation into a pre-section and a post-section, the section is segmented. The power output of the fuel cell system is then determined before and after the point with the largest critical delta, ensuring that the fuel cell operates at a constant power output in each segment. This process is repeated iteratively until there is no longer a point with a critical delta for the entire journey. The route segments, in particular the pre-route segments and post-route segments generated by segmentation, where the delta is non-critical at any point along their course, are not subjected to any further iteration, but are stored in the control unit according to step 205, with the pre-cycle power or post-cycle power prevailing at the fuel cell. A critical pre-delta in the pre-slice segment is detected if the pre-delta is positive at at least one point in the pre-slice segment when the battery is discharged or negative when the battery is charged, and a non-critical delta is detected in all other cases. A critical post-delta in the post-track segment is detected if the post-delta is positive at at least one point in the post-track segment when the battery is discharged or negative when the battery is charged, and a non-critical delta is detected in all other cases. The iterations are performed for the pre-route segments and / or post-route segments where a critical delta is detected at a point within the route segment. This continues until the entire journey is divided into individual route segments, all of which contain a non-critical delta at every point. This allows the journey to be segmented in just a few iterations so that the fuel cell is operated at constant power in each individual route segment. The proposed iterative fuel cell operation optimization segments the entire journey into route segments in which the fuel cell operates at a constant power output. The computational requirements for this are significantly lower than those of the previously described, known predictive energy management methods. The proposed algorithm eliminates the need for filtering the fuel cell's power demand, a process essential in the currently used algorithm. Furthermore, the described method requires less storage and computational effort. This enables a reduction in storage requirements and computational effort to significantly less than half compared to currently used predictive energy management methods. In principle, it is conceivable that fuel cell operation optimization could be performed until the delta is non-critical at every point in every route segment. It proves advantageous to terminate the fuel cell operation optimization upon reaching a predefined or definable number of iterations or a specific performance criterion. This allows the fuel cell operation optimization to be limited to a maximum number of iterations. This makes it possible to keep storage capacity and computational effort low. The maximum number of iterations is calibratable and can include a maximum of 30 iterations, in particular a maximum of 20 iterations. One quality criterion could be, for example, an acceptable critical delta relative to the usable battery energy window, which could be, for example, 1% or less. It proves advantageous if a detected negative delta at a point in the journey represents an exceedance, if a detected positive delta at a point in the journey represents a fall below the limit, and if a detected delta of zero at a point in the journey represents the coverage of the energy requirement of the drive system at that point by the sum of the energy provided by the fuel cell power and the usable battery energy window at that point. In one embodiment of the method, it is provided that two adjacent sections of the route differ at least in speed limits and / or in gradients and inclines in the respective section, that the acquisition of route information for the sections includes at least the length of the section, existing speed limits and / or gradients in the section, and / or that the acquisition of the respective energy requirement of the drive system for each section is based on the route information. Furthermore, it proves advantageous if a route segment includes at least one of the at least one route section. Because a route segment includes at least one of the at least one route section, the number of iterations can be limited in such a way that the fuel cell operation optimization iteration is terminated at least when there is the same number of route segments as route sections. The total energy requirement for the entire journey can, in principle, be arbitrary. In one embodiment of the method, determining the total electrical energy requirement for the entire journey includes the sum of the energy requirements of the drive system for all route segments and the charging energy required to recharge the battery from its actual state of charge at the beginning of the journey to a stored or storable target state of charge at the end of the journey. Within each section of the route, the energy demand at the edges can be determined for each segment, based on route information such as gradient and speed limit. By recording the speed limit, the highest speed the driver of the vehicle is likely to reach in that section can be estimated. Therefore, the total energy demand always includes the maximum possible energy required to travel the entire route at the permitted maximum speed. To ensure that a battery energy window is always available, it proves advantageous if, when a non-critical delta is detected at a point in the route segment, where the difference between the energy requirement of the drive system in the route segment and the energy provided by the cycle power of the fuel cell in the route segment is negative and smaller in absolute value than the maximum battery energy window usable for charging, the battery is charged by the fuel cell system if the battery is below a stored or storable maximum state of charge. In route segments where the actual state of charge is equal to or below a definable or definable minimum state of charge of the battery, the battery energy window for discharging is zero, but for charging it is equal to the battery energy window. To estimate the maximum possible battery window, one embodiment of the method provides that the determination of a usable battery energy window of the battery in the sections of the respective route segment is calculated by multiplying the product of one hundredth of the battery capacity by the difference between the determined target state of charge of the battery at the end of the respective route segment and the determined actual state of charge of the battery at the beginning of the respective route segment. The battery should be charged in the route section if the target state of charge is greater than the actual state of charge, and discharged if the target state of charge is less than the actual state of charge. Charging is limited by a maximum battery charge level, which can be less than 100%, and discharging by a minimum battery charge level, which can be greater than 0%. Alternatively or additionally, it proves advantageous if determining the usable battery energy window of the battery in the sections of the respective route segment includes the difference between the maximum permissible state of charge of the battery in the respective route segment and the minimum permissible state of charge of the battery in the respective route segment. Furthermore, the problem is solved by a fuel cell electric vehicle with an electric drive system, with at least one battery, with a fuel cell system comprising at least one fuel cell in which electrical energy can be generated and supplied to the battery and / or the electric drive system, and with at least one control unit by which at least the electric drive system, the battery and the fuel cell system can be controlled, wherein the fuel cell electric vehicle can be operated with a method according to at least one of the aforementioned claims. Further features, details and advantages of the invention will become apparent from the attached patent claims, the graphic representation and the following description of preferred embodiments of the method and the fuel cell electric vehicle. The drawing shows: Fig. 1 A schematic top view of an embodiment of the fuel cell electric vehicle according to the invention; Fig. 2 A schematic flowchart of an embodiment of the method according to the invention; Fig. 3 An embodiment of a fuel cell operating optimization of the method according to Fig. 2; Fig. 4 A graphical representation of the energy requirements of the drive system, the electrical energy supplied by the fuel cell, and the battery energy window of the method according to Fig. 2 without iteration; Fig. 5 A graphical representation of the energy requirements of the drive system, the electrical energy supplied by the fuel cell, and the battery energy window of the method according to Fig. 2 after a first iteration according to Fig. 3; Fig.6 A graphical representation of the energy requirements of the drive system, the electrical energy supplied by the fuel cell and the battery energy window of the method according to Fig. 2 after a second iteration according to Fig. 3. Fig. 1 shows a schematic representation of a fuel cell electric vehicle, designated as reference numeral 2. This comprises a fuel cell system 4 with a fuel cell 6. In the embodiment shown in Fig. 1, the fuel cell system 4 also includes a fluid tank 8 in which a fluid is stored. The fluid can be supplied from the fluid tank 8 to the fuel cell 6, in which electrical energy is generated by inverse electrolysis. Furthermore, the fuel cell electric vehicle 2 includes a battery 10, which is a high-voltage battery. A converter 12 is connected upstream and downstream of this battery. An electric drive system 14 is connected downstream of the battery 10. This drive system powers the wheels 16. With reference to the illustration in Fig. 1, a method for operating such a fuel cell electric vehicle 2 is described below in Fig. 2: In step 100, a control unit 18 records all sections of a journey. In addition, in step 100, the energy demand of the drive system 14 in the sections of the journey is recorded, and all sections are combined into a single route segment SEG. The individual route segments are defined by the fact that two adjacent route segments differ at least in speed limit and / or in gradient and incline in the respective route segment. Route information can be recorded for each section, including at least the length of the sections, existing speed limits, and / or any gradients. The respective energy requirement of the drive system 14 in each section can then be determined based on this route information. In step 101, a total energy requirement for the entire journey is determined. This can be composed of the energy requirements of the drive system 14 for each route segment based on the route information. In a subsequent step 102, a usable battery energy window for charging and discharging battery 10 is determined for each section of the route segment SEG. In step 103, a constant cycle power of the fuel cell 6 is determined over the route segment SEG to provide the total energy requirement. In step 104, deltas are recorded at each point of the route segment SEG. The respective delta is calculated as the difference between the energy demand of the drive system 14 on the one hand and the sum of the energy provided by the cycle power of the fuel cell 6 and the usable battery energy window on the other. If the delta at each point of the route segment SEG is non-critical, in step 104i, the fuel cell system 4 is operated constantly with the determined cycle power of the fuel cell 6 throughout the entire journey. If the delta is critical at at least one point in the SEG route segment, fuel cell operating optimization is performed. A delta is critical if it is negative at at least one point in the SEG route segment during charging, or positive at at least one point in the SEG route segment during discharging. The fuel cell operating optimization determines route-segment-dependent cycle powers for fuel cell 6, which are used to operate fuel cell 6 at a constant rate across different SEG route segments. Fig. 3 shows a schematic flowchart of a fuel cell operating optimization. This includes step 104 ii. of the representation according to Fig. 2. In a first step 200, the position of the point of the critical, largest delta in the route segment SEG is identified and the amount of the largest critical delta is recorded. In a subsequent step 201, the route segment SEG is divided into a pre-route segment PRE-SEG, which includes all sections of travel before the point of the largest critical delta, and a post-route segment POST-SEG, which includes all sections of travel after the point of the largest critical delta. In a subsequent step 202, a constant pre-cycle power of the fuel cell 6 for the pre-route segment PRE-SEG is determined, with a delta at the location of the previously largest critical delta being zero. In a subsequent step 203, a constant post-cycle power of the fuel cell 6 for the post-route segment POST-SEG is determined from the total energy requirement subtracted from the sum of the energy provided by the pre-cycle power of the fuel cell 6. In a subsequent step 204, all pre-deltas at each point of the pre-route segment PRE-SEG are recorded. These deltas are calculated as the difference between the energy demand of the drive system 14 at each point of the pre-route segment PRE-SEG and the sum of the energy provided by the pre-cycle power of the fuel cell 6 and the usable battery energy window at the same point. Furthermore, in step 204, all post-deltas at each point of the post-route segment POST-SEG are recorded. These deltas are calculated as the difference between the energy demand of the drive system 14 at each point of the post-route segment POST-SEG and the sum of the energy provided by the post-cycle power of the fuel cell 6 and the usable battery energy window at the same point. If the measured pre-deltas are non-critical at every point in the pre-route segment PRE-SEG, in step 205 the fuel cell system 4 is operated at a constant rate with the determined pre-cycle power of fuel cell 6 in the pre-route segment PRE-SEG. Alternatively or additionally, the fuel cell system 4 can be operated with the determined post-cycle power of fuel cell 6 in the post-route segment POST-SEG if the post-delta is non-critical at every point in the post-route segment POST-SEG. However, if the delta is critical at a point in the pre-route segment PRE-SEG, in step 206 the pre-route segment PRE-SEG is equated with the route segment SEG, the pre-delta with the delta, and the total energy with the energy provided by the pre-cycle power of fuel cell 6, and steps 200 for 205 are performed for the pre-route segment PRE-SEG. The same applies to the post-route segment POST-SEG if the delta is critical at any point in the post-route segment POST-SEG. Accordingly, in step 206, the post-route segment POST-SEG is equated with the route segment SEG, the post-delta with the delta, and the total energy with the energy provided by the post-cycle power of the fuel cell, and steps 200 to 205 are executed. The previously described fuel cell operation optimization can be performed until the deltas are non-critical in all route segments. Furthermore, a maximum possible number of iterations can be defined. Figures 4, 5 to 6 show illustrations of different calculation steps of the iterative method described in Figures 2 and 3. The top row of each figure plots the energy supplied by the fuel cell 6 and the energy demand of the electric drive system 14 over time. The fuel cell power output is shown in the middle row. In the bottom row of each figure, the delta is formed at each position from the difference between the energy requirement of the drive system 14 on the one hand and the sum of the energy provided by the cycle power of the fuel cell 6 and the usable battery energy window on the other. The dashed line A shows the boundary of the usable battery energy window when discharging battery 10, and the dashed line B shows the boundary of the usable battery energy window when charging battery 10. A critical delta exists above line A and below line B. Before the first iteration, the usable battery energy window lies between lines A and B. Fig. 4 shows the procedure before performing the iteration according to step 104 ii. of the fuel cell operation optimization. Fig. 5 shows the representation shown in Fig. 4 after a first iteration of steps 200 to 206. It becomes apparent, particularly with regard to the middle column, that the cycle power of the fuel cell 6 has been divided into a constant pre-cycle power and a constant post-cycle power. In the bottom row, the lower graph shows the now improved energy supply by the fuel cell 6 through the provision of the pre-cycle and post-cycle power. Fig. 6 shows the process after a second iteration. In this iteration, the pre-route segment PRE-SEG from the first iteration became the route segment SEG from the second iteration, and the post-route segment POST-SEG from the first iteration became the route segment SEG from the second iteration. These were then further subdivided, as in the first iteration, into a pre-route segment PRE-SEG and a post-route segment POST-SEG. This results in four different cycle power outputs for the fuel cell 6 in the second iteration, at which it can be operated. Looking at the bottom diagram in Fig. 6, it becomes clear that the critical deltas remaining after this iteration are significantly reduced, so that further iterations are only necessary in intermediate ranges. The features of the invention disclosed in the foregoing description, in the claims and in the drawing may be essential, both individually and in any combination, in the realization of the invention in its various embodiments within the scope of protection of the following claims. Reference symbol list 2 Fuel cell electric vehicle 4 Fuel cell system 6 Fuel cell 8 Fluid tank 10 Battery 12 Converter 14 Drive system 16 Wheels 18 Control unit SEG Route segment PRE-SEG Pre-route segment POST-SEG Post route segment

Claims

Method for operating a fuel cell electric vehicle (2) with an electric drive system (14), with at least one battery (10), with a fuel cell system (4) comprising at least one fuel cell (6) in which electrical energy can be generated and supplied to the battery (10) and / or the electric drive system (14), and with at least one control unit (18) by which at least the electric drive system (14), the battery (10) and the fuel cell system (4) can be controlled, comprising the steps: a. 100: Recording all sections of the journey, recording the energy demand of the drive system (14) in the sections of the journey and combining all sections into a single route segment (SEV); b. 101: Determining a total electrical energy demand for the entire journey; c.102: Determining a usable battery energy window for charging and discharging the battery (10) for each section of the route segment (SEG); d. 103: Determining a constant cycle power of the fuel cell (6) over the route segment (SEG) to provide the total electrical energy demand; e. 104: Determining a delta at each point of the route segment (SEG), formed from the difference between the energy demand of the drive system (14) on the one hand and the sum of the energy provided by the cycle power of the fuel cell (6) and the usable maximum battery energy window on the other hand, wherein a critical delta in the route segment is determined if the delta at at least one point of the route segment (SEG) is positive when discharging the battery (10) or negative when charging the battery (10), and wherein a non-critical delta is determined in all other cases, undi.constant operation of the fuel cell system (4) with the determined cycle power of the fuel cell (6) over the entire journey, if the delta is non-critical at every point of the route segment (SEG); orii. Performing a fuel cell operating optimization to determine route segment-dependent cycle powers of the fuel cell (6) with which the fuel cell (6) is operated constantly in different route segments (SEG), if the delta is critical at at least one point of the route segment (SEG). The method according to claim, characterized in that the fuel cell operating optimization comprises the following iteratively executable steps for each route segment (SEG) that includes at least one critical delta at a location: a. 200: Identifying the position of the location of the largest critical delta in the route segment (SEG) and determining the magnitude of the largest critical delta; b. 201: Dividing the route segment (SEG) into a pre-route segment (PRE-SEG) comprising all driving segments before the location of the largest critical delta, and a post-route segment (POST-SEG) comprising all driving segments after the location of the largest critical delta; c. 202: Determining a constant pre-cycle power of the fuel cell (6) for the pre-route segment (PRE-SEG) such that a delta at the location of the previous largest critical delta is zero; d.203: Determining a constant post-cycle power of the fuel cell (6) for the post-route segment (POST-SEG) from the total electrical energy demand subtracted from the sum of the energy provided by the pre-cycle power of the fuel cell (6);e.204: Capturing a pre-delta at each point of the pre-route segment (PRE-SEG), formed from the difference between the energy demand of the propulsion system (14) at each point of the pre-route segment (PRE-SEG) on the one hand and the sum of the energy provided by the pre-cycle power of the fuel cell (6) and the usable maximum battery energy window at the same point on the other hand; and capturing a post-delta at each point of the post-route segment (POST-SEG), formed from the difference between the energy demand of the propulsion system (14) at each point of the post-route segment (POST-SEG) on the one hand and the sum of the energy provided by the post-cycle power of the fuel cell (6) and the usable maximum battery energy window at the same point on the other hand; f.205: Constant operation of the fuel cell system (4) with the determined pre-cycle power of the fuel cell (6) in the pre-route segment (PRE-SEG), if the pre-delta at every point of the pre-route segment (PRE-SEG) is non-critical and / or constant operation of the fuel cell system (4) with the determined post-cycle power of the fuel cell (6) in the post-route segment (POST-SEG), if the post-delta at every point of the post-route segment (POST-SEG) is non-critical; org.206: Equating the pre-route segment (PRE-SEG) with the route segment (SEG), the pre-delta with the delta and the total energy with the energy provided by the pre-cycle power of the fuel cell (6) and proceeding through steps 200 to 205 if the pre-delta is critical at at least one point in the pre-route segment (PRE-SEG) and / or equating the post-route segment (POST-SEG) with the route segment (SEG), the post-delta with the delta and the total energy with the energy provided by the post-cycle power of the fuel cell (6) and proceeding through steps 200 to 205 if the post-delta is critical at at least one point in the post-route segment (POST-SEG). Method according to claim 1 or 2, characterized in that the fuel cell operation optimization is terminated upon reaching a stored or storeable number of iterations or when a stored or storeable quality criterion is achieved. Method according to one of the preceding claims, characterized in that a detected negative delta at a point in the journey comprises an exceedance, a detected positive delta at a point in the journey comprises a fall below, and a detected delta equal to zero at a point in the journey comprises covering the energy requirement of the drive system (14) at the respective point by the sum of energy provided by the fuel cell power and usable battery energy window at the respective point. Method according to one of the preceding claims, characterized in that two adjacent sections of the route differ at least in speed limit and / or in gradient and incline in the respective section, that the acquisition of route information of the sections includes at least the length of the section, existing speed limit and / or an incline or a gradient in the section and / or that the acquisition of the respective energy requirement of the drive system (14) for each section is based on the route information. Method according to one of the preceding claims, characterized in that a track segment (SEG) comprises at least one of the at least one track section. Method according to one of the preceding claims, characterized in that the determination of the total energy requirement for the entire journey comprises the sum of the electrical energy requirements of the drive system (14) of all route sections and charging energy for charging the battery (10) from an actual state of charge at the beginning of the journey to a stored or storable target state of charge at the end of the journey. A method according to one of the preceding claims, characterized in that when a non-critical delta is detected at a point in the route segment (SEG), wherein the difference between the energy provided by the cycle power of the fuel cell (6) in the route segment (SEG) and the energy requirement of the drive system (14) in the route segment (SEG) is positive and smaller in magnitude than the maximum battery energy window usable for charging, the battery (10) is charged by the fuel cell system (4) if the battery (10) is below a stored or storable maximum state of charge. Method according to one of the preceding claims, characterized in that the determination of a usable battery energy window of the battery (10) for charging and / or discharging the battery (10) in the sections of the respective route segment (SEG) is the product of one hundredth of the capacity of the battery (10) multiplied by the difference of determined target state of charge of the battery (10) at the end of the respective route segment subtracted by the determined actual state of charge of the battery (10) at the beginning of the respective route segment. Fuel cell electric vehicle (2) with an electric drive system (14), with at least one battery (10), with a fuel cell system (4) comprising at least one fuel cell (6) in which electrical energy can be generated and supplied to the battery (10) and / or the electric drive system (14), and with at least one control unit (18) by which at least the electric drive system (14), the battery (10) and the fuel cell system (4) can be controlled, wherein the fuel cell electric vehicle (2) can be operated using a method of claims 1 to 9.

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