DE102019132088A1 - Fuel cell system, method for operating a fuel cell system, vehicle, air conditioning system - Google Patents

Abstract

The invention relates to a fuel cell system (1000, 1000 ', 1000 ") for providing a power output (PO), comprising: a fuel cell (100) for generating an amount of energy (E, EE, EM, ET) for the power output (PO) and - an energy store (300) for storing the amount of energy (E, EE, ET), - a control device (400, 400 ', 400 ") which is designed in an operation to control the fuel cell (100), with a power specification (LV ) is specified for the fuel cell (100) for controlling the power output (PO), the fuel cell (100) being assigned an efficiency (WG) as a function of a fuel cell power (PB). According to the invention, it is provided in the fuel cell system that- for an efficiency-improved operation, the power specification (LV) is dependent on the state of charge (LZ) of the energy store (300).

Description

The invention relates to a fuel cell system according to the preamble of claim 1.

The invention also relates to a method according to claim 17 and to a vehicle and an air conditioning system.

Fuel cells are well known. By means of a fuel cell - or in particular a plurality of fuel cells in the form of a fuel cell stack - electrical energy and / or heat can be generated from the chemical reaction energy of a fuel and an oxidizing agent. Fuel cells are used in numerous applications, particularly in vehicle drives or in heating systems.

EP 2 491 612 B1 describes a method for managing a state of charge of a battery in a hybrid power supply network with a fuel cell. The method described aims in particular at keeping the state of charge of a battery at a predetermined level by means of a fuel cell.

The problem with such an approach, however, is that, although an optimal state for the battery is achieved, the state and the efficiency of the fuel cell or the fuel cell stack are not taken into account.

This is where the invention comes in, the task of which is to increase the efficiency of a fuel cell system and to protect the condition of the fuel cell, in particular to reduce its wear and tear.

• - eine Brennstoffzelle zum Erzeugen einer Energiemenge für die Leistungsabgabe und
• - einen Energiespeicher zum Speichern der Energiemenge,
• - eine Steuereinrichtung, die ausgebildet ist in einem Betrieb zum Steuern der Brennstoffzelle, wobei eine Leistungsvorgabe für die Brennstoffzelle zum Steuern der Leistungsabgabe vorgegeben wird, wobei
• - der Brennstoffzelle ein Wirkungsgrad in Abhängigkeit einer Brennstoffzellen-Leistung zugeordnet ist.

The object is achieved by the invention with a fuel cell system of claim 1. The invention is based on a fuel cell system for providing a power output, having:

• - A fuel cell for generating an amount of energy for the power output and
• - an energy store for storing the amount of energy,
• - A control device which is designed in an operation to control the fuel cell, wherein a power specification for the fuel cell for controlling the power output is specified, wherein
• - The fuel cell is assigned an efficiency as a function of a fuel cell output.

• - für einen wirkungsgrad-verbesserten Betrieb die Leistungsvorgabe abhängig vom Ladezustand des Energiespeichers erfolgt.

According to the invention it is provided in the fuel cell system that

• - For an efficiency-improved operation, the power specification is made depending on the state of charge of the energy store.

The fuel cell is assigned an efficiency as a function of a fuel cell output, in particular in the form of a relative nominal output of the fuel cell, in particular as an efficiency characteristic stored in the control device.

The invention is based on the consideration that it is fundamentally advantageous to provide an energy store in a fuel cell system for storing an amount of energy generated by the fuel cell. In particular, this energy store can be designed to store the energy generated by the fuel cell and to make it selectively available to a consumer and / or thermal consumer, in particular an electrical consumer. This means that energy generated by the fuel cell can be temporarily stored in the energy store and, if required, can be delivered to a consumer and / or thermal consumer. The fuel cell system is preferably operated as a system in combination with the consumer and / or thermal consumer. In this respect, the energy store is arranged on the energy output side of the fuel cell for receiving energy to be output or output by the fuel cell, in particular electrical energy and / or waste heat.

The invention includes the knowledge that - if such an energy store is available - a temporal decoupling of the generation of energy from the consumption of energy is made possible. Due to this flexibility in time, the state and the efficiency of the fuel cell can advantageously be taken into account in the overall control of the fuel cell system.

The invention has recognized that, with regard to the efficiency of the fuel cell, it is advantageous to take into account the efficiency of the fuel cell, which depends on a fuel cell output, when determining a power specification for the fuel cell. This consideration is in the form that in an efficiency-improved operation, the output specification specifies a reduced fuel cell output. As a result of a reduced fuel cell output, the fuel cell is advantageously operated with an increased degree of efficiency.

The efficiency of a fuel cell - and in particular a fuel cell stack - has a course over its Fuel cell power, which at a low fuel cell power - in particular an amount of a tenth of the fuel cell power - has its maximum. This means that a fuel cell works most effectively with such a relatively low fuel cell output, that is to say generates a relatively high output with a relatively low fuel consumption. For higher values of the fuel cell power, the efficiency usually drops, which is why it is generally advantageous with regard to the efficiency to select an operating point by specifying a corresponding fuel cell power which is as close as possible to the efficiency-optimized operating point, i.e. the fuel cell -Power at which maximum efficiency is achieved.

In this context, the invention has recognized that it is advantageously possible in a fuel cell system with an energy store to operate the fuel cell in efficiency-improved operation if the output specification is determined accordingly, taking into account the state of charge of the energy store, because in this way a possibly lower fuel cell power when providing the power output can be compensated for by an amount of energy stored in the energy store.

Such a fuel cell system uses the leeway created by an energy store to operate the fuel cell with a lower fuel cell output, but with a higher degree of efficiency; in other words, in an efficiency-improved operation.

Efficiency-optimized operation with maximum efficiency of the fuel cell corresponds to a special case of efficiency-improved operation. An efficiency-improved operation is an operation of the fuel cell that - against the background of the required energy requirement and the current state of charge of the energy storage device - comes closest to the efficiency-optimized operation, i.e. represents the highest possible efficiency under these circumstances. As a result of the efficiency-improved operation with a reduced fuel cell output, the best possible efficiency of the fuel cell for a specific application can advantageously be achieved in each case. This is particularly advantageous in the case in which the state of charge is no longer sufficient for optimum efficiency to achieve a target state because the fuel cell output in optimum efficiency would be too low in this case.

• - eine Brennstoffzelle zum Erzeugen einer Energiemenge für die Leistungsabgabe und
• einen Energiespeicher zum Speichern der Energiemenge,
• - eine Steuereinrichtung, die ausgebildet ist in einem Betrieb zum Steuern der Brennstoffzelle, wobei
• - der Brennstoffzelle ein Wirkungsgrad in Abhängigkeit einer Brennstoffzellen-Leistung zugeordnet ist, und das Verfahren den Schritt aufweist:
• - Vorgeben einer Leistungsvorgabe für die Brennstoffzelle zum Steuern der Leistungsabgabe.

In order to achieve the object, the invention also leads to a method of claim 17. The method for operating a fuel cell system has:

• - A fuel cell for generating an amount of energy for the power output and
• an energy store for storing the amount of energy,
• - A control device which is designed in an operation for controlling the fuel cell, wherein
• - The fuel cell is assigned an efficiency as a function of a fuel cell output, and the method has the step:
• - Specifying a power specification for the fuel cell for controlling the power output.

• - für einen wirkungsgrad-verbesserten Betrieb die Leistungsvorgabe abhängig vom Ladezustand des Energiespeichers erfolgt.

In the method according to the invention it is provided that

• - For an efficiency-improved operation, the power specification is made depending on the state of charge of the energy store.

When carrying out the method, the advantages of the fuel cell system described above are used accordingly.

The invention also leads to the solution of the object in a vehicle with a fuel cell system according to the concept of the invention.

In order to achieve the object, the invention also leads to an air conditioning system with a fuel cell system according to the concept of the invention and a thermal consumer. In the air conditioning system, the fuel cell system provides in particular a thermal power output for the thermal consumer for use in a heating and / or cooling application.

In the vehicle and in the air conditioning system, the advantages of the fuel cell system are used accordingly.

Advantageous further developments of the invention can be found in the subclaims and indicate in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

The term efficiency is to be understood in particular as the efficiency with which the input products of a fuel cell, in particular oxygen and hydrogen, are converted into energy. When the fuel cell system is used with an electrical consumer, the efficiency therefore relates to the electrical energy generated. In particular, in the context of a further development for the control device, values relating to the degree of efficiency, in particular as a characteristic curve, are shown in Dependence of the fuel cell power provided.

It is advantageously provided that, for the efficiency-improved operation, the output specification according to the value specifications, in particular the output specification, is a relative nominal output compared to the full (100%) PREL ) or current (<100% PREL ) Power specifies reduced fuel cell power in such a way that the efficiency according to the value data is increased compared to the efficiency at nominal power or the current efficiency.

The reduction in the fuel cell output relates in particular to an output fuel cell output, in particular to a fuel cell output that is normal in operation according to the prior art, namely that which only results in order to - together with the output provided by the energy store - without Consideration of an efficiency - to provide a power output.

It is advantageously provided that an adjustment amount for the reduced fuel cell power is dependent on the state of charge of the energy store. To take into account the compensation for the lack of fuel cell power by the energy store, an adjustment amount is advantageously introduced as a measure for the reduction in the fuel cell power by an amount that is covered by the state of charge of the energy store. If the energy store is relatively fully charged and thus has a high state of charge, a relatively large proportion can be taken from the energy store to provide the power output and the proportion provided by the fuel cell power of the fuel cell can be correspondingly lower, which creates a greater margin, reduce fuel cell performance in favor of higher efficiency; in particular on the basis of a curve of the efficiency in relation to fuel cell performance. This leeway is defined by the adjustment amount - an illustrative, non-restrictive example is based on a preferred embodiment of FIG 7th explained, which shows the course of the efficiency.

In the context of a further development, it is provided that the output specification for the efficiency-improved operation is determined when the charge state of the energy store is above a lower state of charge and / or below an upper state of charge. In a development of this type, it is advantageously ensured that the fuel cell system is only operated in an efficiency-improved mode if the state of charge of the energy store allows this in a technically meaningful manner. If the state of charge does not allow this, it is advantageous to react accordingly.

One reaction can be that, if the charge state of the energy store falls below a lower charge state, the control device reacts accordingly and, for example, sets the power specification in such a way that the fuel cell output provides the entire power output without resorting to the energy store. In such a case, there is in particular no reduction in the non-fuel cell output in order to achieve an improved degree of efficiency.

A reaction can also be that, if the state of charge is above an upper state of charge, the fuel cell is operated at a reduced operating point, in particular partially or completely, by means of the power specification, in particular independently of the power requirement. Specifically, this can include that when it is determined by the control device that the energy store has reached an upper state of charge, the control device reduces the power of the fuel cell, in particular shuts off the fuel cell completely. It is thus achieved that in the event that the state of charge is above the upper state of charge but still below a maximum state of charge - possibly harmful to the energy store - the operation of the fuel cell is reduced or completely throttled. “Completely throttled” in this case means that the fuel cell is switched off or the output power of the fuel cell is reduced to practically zero. In this way, damage to the energy store, in particular a battery, due to overcharging or overheating is advantageously prevented.

The control device can also switch the fuel cell to a regeneration mode, in particular in a third operating mode, in which the current power requirement is met and, moreover, the energy store is recharged.

As part of a further development, it is provided that the control device is designed in the company to accept a performance request. In such a development, a target value for a power output of the fuel cell system can be specified by means of a power request. In such a further development, the concept of the invention can be used advantageously: If there is a short-term need for a high power output due to a high power requirement, for example because the driver of a vehicle with a fuel cell system of this further development is about to accelerate, this can generally be covered in the fuel cell system by an amount of energy stored in the energy store, in particular without the fuel cell having to leave the efficiency-improved operation.

Such a development also enables the energy store to be charged, in particular in a second operating mode, in periods in which there is no need for energy on the part of the consumer. This charging can take place particularly advantageously in that the fuel cell is operated in the efficiency-improved mode. This is particularly advantageous because in many systems supplied by fuel cells, in particular vehicles, there are sometimes long periods of standstill or pause in which the energy storage device is charged by a fuel cell operated in efficiency-improved operation with reduced fuel cell power due to the availability of the fuel cell standing time is easily possible.

In such a development with a fuel cell system according to the invention, the fuel cell can also be continuously, i.e. H. operated independently of briefly occurring and / or briefly lasting power requirements and thus frequent switching on and off of the fuel cell can be avoided. Because the starting process of a fuel cell is relatively complex due to processes such as the flushing process and the startup of the turbocharger required to supply compressed air to the fuel cell, frequent switching on and off of the fuel cell results in increased wear and thus premature aging of the fuel cell and the fuel cell system.

By operating the fuel cell - in particular continuously - in an efficiency-improved mode, frequent switching on and off, which is mainly caused by short-term and / or short-term power requirements, is advantageously avoided. Instead, the system can be operated for longer at an operating point at which an improved, in particular maximum, efficiency is achieved. In this way, the wear on the fuel cell and the fuel cell system can advantageously be reduced and, at the same time, the efficiency of the fuel cell can be increased.

In the context of a further development, it is provided that the output specification for the efficiency-improved operation takes place as a function of a charge state of the energy store in such a way that the power output corresponds to the power requirement. In a development of this type, the control device in particular is advantageously designed to provide a power requirement specified for the fuel cell system as a setpoint value in the sense of a control loop as a power output.

In the context of a further development, it is provided that the determination of the efficiency-improved operation takes place in such a way that the power requirement results from the power specification and the state of charge of the energy store.

As part of a further development, it is provided that the determination of the output specification for the efficiency-improved operation takes place in such a way that a target amount of energy required to achieve a target state results for a forecast period in the future from the output specification and the state of charge of the energy store. In particular, the target amount of energy is a cumulative power requirement (KLA) that cumulatively takes into account the entirety of a forecast period in the future and thus represents the integral of the performance requirements forecast in the forecast period, i.e. the integral of the target values for the power output.

Specifically, this can include that the control device has a predictive observer who is designed to predict, on the basis of existing data, with sufficient accuracy a target amount of energy that is required to reach the target state. The target amount of energy thus represents an energy horizon which can be adapted by updating the prognosis, in particular in the case of changing operating, ambient or similar boundary conditions.

In particular, the control device has a predictive observer for determining the amount of energy required up to a target state, in particular a target position.

In the context of a further development, it is provided that the specification of the power output is determined in such a way that the target amount of energy is determined as a function of a predicted power profile, in particular a predicted driving profile. A predicted power profile is an estimate of the power output required by the consumer, in particular the required electrical or thermal power, for a future period of time. The more precisely the temporal resolution of this estimate and the more data on consumption are taken into account, in particular actual data such as position data, status data and data on environmental influences, the better the quality of the prognosis and thus the estimate of the expected energy consumption in the form of the target -Energy amount.

As part of a further development, it is provided that the determination of the performance specification takes place in such a way that the predicted performance profile is calculated on the basis of one or more actual data, in particular an actual position, and one or more target data, in particular one or more target positions or segment target positions.

In a fuel cell system that is used in a vehicle that has a drive, an actual date can be, for example, an actual position determined by a GPS sensor or navigation device. Target data can be target position data which arise from a target route. The target state is formed here, for example, by a target position as the target at the end of the target route. From these actual data and target data, a route can be calculated from which the energy required to reach the target state can be estimated. It is also advantageously possible to divide the forecasted performance profile into several profile segments and to carry out a forecast for each segment. When the fuel cell system is used in a vehicle, the target route can be divided into several target route segments, each with a segment target state, and a segment target state in the form of a segment target position can be determined for each target route segment become.

The more influences on the energy consumption are taken into account in the calculation, for example height differences, weather conditions, route conditions, etc., the better the target amount of energy can be estimated. In order to be able to compensate for possible inaccuracies in the estimations of the conditions, it is advantageous to plan in a certain additional amount of energy as a buffer. In this way, it is prevented that the fuel cell system has to leave the efficiency-improved operation due to an imprecise estimate before reaching the target state, for example, since the state of charge of the energy store is too low.

Furthermore, profile data can be taken into account which, for example, take into account differences between different users, for example drivers of a vehicle, or different machine types, for example different vehicle types, in consumption.

As part of a further development, it is provided that the consumer is an electric drive and the energy storage device is a battery. This can specifically include that the fuel cell system is used in a vehicle, and there the control device can operate the fuel cell according to the concept of the invention at an operating point that is optimized for efficiency. In this way, the fuel cell can advantageously generate electrical drive energy with improved efficiency, which can be temporarily stored in an energy store designed as a battery and fed to an output connection for power output as required and provided to one or more electrical drives of the vehicle. In such a development, other electrical loads can also be supplied via the fuel cell system.

In the context of a further development it is provided that the fuel cell system is designed to provide a thermal power output. Specifically, this can mean that the fuel cell generates thermal energy in the form of heat, in particular in the form of waste heat when generating electrical energy.

Within the scope of a further development, it is provided that the control device is designed to accept a further power requirement in the form of a thermal power requirement and to determine the specified performance as a function of the thermal performance requirement. Specifically, this means that a further setpoint generator, for example in the form of a thermostat, specifies a setpoint for a temperature that is to be achieved in a thermal consumer. In this development, the control device is designed to specify a power specification for the fuel cell, by means of which a thermal power output is provided which corresponds to the thermal power requirement. The control device in this development can be designed to treat one of the two assumed performance requirements, namely the first performance requirement and the second thermal performance requirement, depending on which form of energy - electrical or thermal - is primarily required.

The invention is developed by an energy store designed as a heat store. In such developments, the heat can be temporarily stored in an energy store designed as a heat store, in particular as a hot water store, and can be provided to a consumer, in particular a heater, as required.

In further developments with an energy store designed as a heat store, the concept of the invention for thermal energy can advantageously be implemented in such a way that the fuel cell can be operated with maximum thermal efficiency and, if necessary, an amount of thermal energy stored in the heat store can be used to provide the thermal power output , so that Fuel cell does not have to leave its operating point at maximum thermal efficiency.

In further developments of the fuel cell system that are used in systems that have both a consumer - in particular an electric drive - and a battery, as well as a thermal consumer - in particular a heater - and a heat store, the fact can advantageously be used in a synergetic manner that a fuel cell produces both electrical energy and thermal energy in the form of heat when in operation. Thus, by using both forms of energy, the efficiency of the entire fuel cell system can be increased.

Within the scope of a further development, it is provided that the control device is designed to specify the output specification preferably in a range between 5% and 15%, particularly preferably at 10%, of the fuel cell output. The value of approx. 10% of the fuel cell output represents an approximation of the optimum efficiency of a typical fuel cell - i.e. the fuel cell output at which there is maximum efficiency - and may differ for different fuel cell types.

In a further development of the method it is provided that the performance specification is determined as a function of the performance requirement.

In a further development of the method, it is provided that a target amount of energy required to achieve a target state, in particular an accumulated power requirement, is met for a forecast period in the future.

In a further development of the method it is provided that the target amount of energy is determined as a function of a predicted performance profile, in particular a predicted driving profile.

A further development of the method provides that the forecast performance profile is calculated on the basis of one or more actual data, in particular an actual position, and one or more target data, in particular one or more target positions or segment target positions becomes.

• 1 eine bevorzugte Ausführungsform eines Brennstoffzellensystems gemäß dem Konzept der Erfindung,
• 2 eine bevorzugte Ausführungsform eines Brennstoffzellensystems mit einem thermischen Abnehmer,
• 3 eine weitere Ausführungsform eines Brennstoffzellensystems mit Details eines thermischen Abnehmers,
• 4 eine bevorzugte Ausführungsform eines Verfahrensablaufs zum Betrieb eines Brennstoffzellensystems gemäß dem Konzept der Erfindung,
• 5 eine weitere bevorzugte Ausführungsform eines Verfahrensablaufs zum Betrieb eines Brennstoffzellensystems zur Bestimmung einer Leistungsvorgabe für die Brennstoffzelle,
• 6 eine detaillierte Ansicht einer Steuereinrichtung für eine bevorzugte Au sführungsform,
• 7 eine bevorzugte Ausführungsform einer Wirkungsgrad-Kennlinie als ein schematischer Verlauf des Wirkungsgrads einer Brennstoffzelle aufgetragen über deren relativer Nominalleistung,
• 8 ein schematisches Diagramm des zeitlichen Verlaufs des Ladezustands eines Energiespeichers in einem Brennstoffzellensystem gemäß einer bevorzugten Ausführungsform,
• 9 eine schematische Ansicht eines Fahrzeugs mit einem Brennstoffzellensystem gemäß einer bevorzugten Ausführungsform.

Embodiments of the invention will now be described below with reference to the drawing in comparison to the prior art, which is also shown in part. This is not necessarily intended to represent the embodiments to scale; rather, the drawing, where useful for explanation, is shown in a schematic and / or slightly distorted form. With regard to additions to the teachings that can be seen directly from the drawing, reference is made to the relevant prior art. It must be taken into account that various modifications and changes relating to the shape and detail of an embodiment can be made without deviating from the general idea of the invention. The features of the invention disclosed in the description, in the drawing and in the claims can be essential for the development of the invention both individually and in any combination. In addition, all combinations of at least two of the features disclosed in the description, the drawing and / or the claims fall within the scope of the invention. The general idea of the invention is not limited to the exact form or the detail of the preferred embodiment shown and described below or limited to an object which would be restricted in comparison to the object claimed in the claims. In the case of specified measurement ranges, values lying within the stated limits should also be disclosed as limit values and be able to be used and claimed as required. Further advantages, features and details of the invention emerge from the following description of the preferred embodiments and with reference to the drawing; this shows in:

• 1 a preferred embodiment of a fuel cell system according to the concept of the invention,
• 2 a preferred embodiment of a fuel cell system with a thermal consumer,
• 3rd another embodiment of a fuel cell system with details of a thermal consumer,
• 4th a preferred embodiment of a method sequence for operating a fuel cell system according to the concept of the invention,
• 5 a further preferred embodiment of a method sequence for operating a fuel cell system for determining a power specification for the fuel cell,
• 6th a detailed view of a control device for a preferred embodiment,
• 7th a preferred embodiment of an efficiency characteristic curve as a schematic profile of the efficiency of a fuel cell plotted against its relative nominal power,
• 8th a schematic diagram of the time course of the state of charge of a Energy storage in a fuel cell system according to a preferred embodiment,
• 9 a schematic view of a vehicle with a fuel cell system according to a preferred embodiment.

The embodiments shown in the drawing generally relate to a fuel cell system 1000 according to the concept of the invention to operate for at least one consumer 200 and / or a thermal collector 240 . The fuel cell system 1000 has a fuel cell 100 , here marked with BSZ, here in the form of a fuel cell stack 102 on. The fuel cell system is preferred 1000 in combination with the consumer 200 and / or thermal consumers 240 operated. The energy storage 300 as a rechargeable intermediate storage device, the fuel cell is arranged on the energy output side for receiving energy, in particular electrical energy and / or waste heat, which is given off or given off by the fuel cell.

The in 1 The first embodiment shown is the fuel cell 100 via a supply line 104 and a discharge port 140 with a consumer 200 selectively connectable with current, the present here as an electrical consumer 201 in the form of an electric drive 202 is trained. The electric drive 202 is marked here with D. Electrical power E. that by means of the fuel cell 100 was generated, in particular an amount of electrical energy EE , can thus the consumer 200 be fed to in particular a vehicle 2000 to drive. This is done using the fuel cell 100 Oxygen O2 and / or air AIR as well as hydrogen H2 fed. During the reaction in the fuel cell 100 In particular, water H2O and residual air are produced AIRRES .

The fuel cell 100 is still via a storage line 106 with one as a battery 302 trained energy storage 300 , herewith IT marked, selectively connectable with current carrying. According to the concept of the invention, the battery 302 - In particular, regardless of the operation of the electrical consumer 201 - by the fuel cell 100 generated electrical energy EE to be charged.

Furthermore, there is the delivery connection 140 and a buffer line 108 with the energy storage 300 Can be selectively connected to be live. At the delivery port 140 becomes a power output PO for the consumer 200 provided. The delivery port 140 and the buffer line 108 are bidirectional. In the present case, this means that both one in the battery 302 stored amount of electrical energy EM the electrical consumer 201 can be supplied, as well as that electrical energy from the electrical consumer 201 , in particular by means of recuperation from an electric drive 202 generated electrical energy in the battery 302 can be saved.

The fuel cell system 1000 further has a control device 400 on, here marked as ECU. The control device 400 has a control input 402 on over which a performance requirement LA from a setpoint generator 500 to the control device 400 can be transmitted. Such a performance requirement LA can, for example, if the fuel cell system 1000 like here in the vehicle 2000 is used by the driver directly, for example via an accelerator pedal 501 trained setpoint generator 500 , or, in the case of autonomous vehicles, via an automated speed controller 502 trained setpoint generator 500 . The performance requirement LA is in the control device 400 into a control signal RS converted and via a control output 408 and at a control connection 208 for the consumer 200 , especially as a drive signal AS to the electric drive 202 , are provided to regulate its performance. The control connection 208 can as shown here at the delivery connection 140 be arranged, in particular such that the consumer 200 about the power output PO is controlled, alternatively the control connection 208 also elsewhere, for example directly at the consumer 200 , be arranged. Furthermore, the control signal RS controlled whether the power output via the supply line 104 through a fuel cell power PB , or the buffer line 108 through a storage capacity PS is provided, or whether the power output is provided by a combination of both. The latter can be the case, for example, when the fuel cell 100 in an efficiency-improved operation BPA is operated. Not shown here, but also conceivable, would be an embodiment in which the control device 400 a signal line to the energy store 300 consists, over which the power is regulated, which from the battery 302 via the buffer line 108 to the drive 202 is delivered. In one embodiment with a signal line from the control device 400 to energy storage 300 is thus the over the buffer line 108 transferred service not on the consumer's side 200 , but on the side of the energy storage 300 regulated.

The control device 400 also includes a measuring input 404 about which a charge status LZ of the energy storage 300 which is currently in the energy storage 300 stored amount of energy EM characterized, the control device 400 can be transmitted. The state of charge LZ can for example via a measuring connection 306 of the energy storage 300 are recorded.

The control device 400 furthermore has a control output 406 on over which a performance specification LV to a control input 110 the fuel cell 100 for setting the fuel cell output PB , especially in the form of an operating point BP , can be transmitted. The control device 400 is designed depending on the state of charge LZ a performance target LV for improved efficiency BPA to determine the performance target LV - taking advantage of the energy storage 300 stored amount of energy EM - a fuel cell power PB in the form of reduced fuel cell performance PA corresponds to that of the fuel cell 100 works with the highest possible efficiency. The state of charge is particularly taken into account in order to avoid the reduced fuel cell performance PA a power output PO in the required amount - in particular a performance fee PO that is a performance requirement LA corresponds to - provide.

2 shows a further embodiment of a fuel cell system 1000 ' according to the concept of the invention. This embodiment also has a thermal output connection 150 on to the supply of a thermal consumer 240 . The thermal consumer 240 can in particular a heater 244 and / or a chiller 246 have, here accordingly with HZ / KM Marked are. The fuel cell system 1000 ' additionally has a heat storage unit 304 trained energy storage 300 on, here marked with WS. The heat storage 304 can in particular be designed as a hot water tank. The thermal consumer 240 can in particular be part of an air conditioning system 3000 be. The fuel cell 100 , which in the present case is a fuel cell stack 102 is formed, represents the heat it produces as a thermal amount of energy ET via a thermal supply line 124 and the thermal discharge port 150 in the form of thermal fuel cell power PBT to the thermal consumer 240 to disposal. At the thermal consumer 240 becomes a thermal power output PT provided. Furthermore, the fuel cell represents 100 the heat storage 304 the amount of thermal energy ET via a thermal storage line 126 to disposal. Furthermore, there is - analogously to the electrical design of the first embodiment shown - a fluid and thus heat-carrying connection between the energy store 300 and the consumer 200 , present in the form of a thermal buffer line 128 . Via the thermal buffer line 128 can be a stored amount of thermal energy EMT from the heat accumulator 304 to the thermal output connection 150 as thermal storage capacity PST for the thermal consumer 240 to be provided. Conversely, the thermal consumer 240 a stored amount of thermal energy EMT back to the heat accumulator 304 be transferred. In all cycles 124 , 126 , 128 an appropriate medium suitable for heat transport, for example water, can be used. Via a memory measurement connection 326 can be a thermal state of charge LZT of the heat storage 304 , that is, the amount of heat in the storage tank 304 stored amount of thermal energy EMT to be determined. This can be done in particular by measuring or estimating the temperature and the amount of heat in the heat storage tank 304 contained water (or similar suitable for heating, in the heat storage 304 contained medium) happen.

The control device 400 ' can advantageously be designed as a performance specification LV such as to determine a thermal fuel cell performance PBT the fuel cell 100 taking advantage of the state of charge LZ of the heat storage 304 , is determined such that the fuel cell 100 is operated in an improved thermal efficiency - this is analogous to the (electrical) efficiency of the control device 400 in the first embodiment.

Via a consumer control connection 248 can the thermal power output PT for the thermal consumer 240 from the control device 400 ' being controlled. Here is the consumer control connection 248 at the thermal output connection 150 arranged. In other developments it is also possible to use the consumer control connection 248 at another point, especially directly at the thermal consumer 240 for direct control of the thermal consumer 240 to arrange.

Analogously to the first embodiment shown, the control device 400 ″ determines on the basis of a second, thermal power requirement LAT, which in the case of heating, for example, by a thermostat 521 or an air conditioning controller 522 or the like setpoint generator 500 can be formed, and based on the thermal state of charge LZT of the heat storage 304 a performance target LV for the fuel cell 100 which the fuel cell 100 via the control output 406 and then the control input 110 is transmitted. The thermal power requirement LAT is the control device 400 ' via a second control input 410 provided.

The development shown here can advantageously provide an (electrical) power output in the sense of a power-heat coupling PO and a thermal power output PT combine. In such Further development, the fact that a fuel cell generates energy both in the form of heat and in the form of electrical energy during operation, the approach according to the invention achieving an efficiency-improved operation for both electrical efficiency and thermal efficiency can be. This can also be made possible in a switchable manner by the control device during operation, in particular by adding either an electrical load, as required 200 relevant performance requirement LA , or one, the thermal consumer 240 relevant thermal power requirement LAT is given priority.

In 3rd is a fuel cell system 1000 " shown in a further embodiment. Here is a thermal consumer 240 , as part of a climate system 3000 ' in a vehicle 2000 'not shown in detail, shown in detail. This in 3rd fuel cell system shown 1000 " can in particular serve the primary purpose, a drive 202 for the vehicle 2000 provide. In the 34 The embodiment shown differs from that in FIG 2 embodiment shown in particular in that the fuel cell 100 via a vehicle radiator 130 and a cooling line 132 a cooling medium 134 is supplied to the fuel cell 100 to cool in the sense of a cooling circuit. The thermal supply line is still required for this purpose 124 ' bidirectional in the sense of a cycle. The vehicle radiator 130 is here marked with FK. The vehicle radiator 130 can be part of a vehicle 2000 '(not shown here) and in particular serve for cooling in other applications in the vehicle 2000'. The embodiment shown here also has a heat accumulator 304 in the sense of in 2 embodiment shown, wherein the heat storage 304 is optional. The thermal consumer 240 is present in the form of an air conditioner 242 educated.

The present is a consumer control connection 248 at the thermal output connection 150 arranged. In other developments it is also possible to use the consumer control connection 248 at another point, in particular as a further consumer control connection 248 'directly on the thermal consumer 240 , for direct control of the thermal consumer 240 to arrange. In the present case, this is indicated by the dotted line between the control device 400 ″ and the thermal consumer 240 shown.

The thermal consumer 240 in the present case has a main heat exchanger 250 on, which has another thermal supply line 124A with the cooling medium 134 which is supplied by the fuel cell 100 was heated. The thermal energy thus obtained ET can continue through a primary circuit 260 to a chiller 246 be passed on. About the chiller 246 the thermal energy can now be used for various applications, in particular in the vehicle 2000 '. For example, the thermal energy ET via a device circuit 262 by means of a suitable medium to a device heat exchanger 252 are conducted, the device heat exchanger 252 can be used in particular for heating applications. It is also possible by means of the refrigeration machine 246 To produce cold air, which via a cold air duct 264 directly to an air conditioning system 254 can be delivered.

The cooling medium 134 can after it is the main heat exchanger 250 has happened via a first cooling return line 138 in the vehicle radiator 130 be returned. The supply line 124 ' shows a switch 136 on, by means of which the flow of the cooling medium 134 via three different course settings P1 , P2 , P3 can be directed. When the switch 136 in the first setting of the course P1 is located, the cooling medium 134 as already described to the main heat exchanger 250 of the thermal consumer 240 directed. When the switch 136 in a second position P2 is located, the cooling medium 134 via a second cooling return line 138.2 at the thermal consumer 240 passing straight back into the vehicle radiator 130 directed. When the switch 136 in a third position P3 is located, the cooling medium 134 , past the thermal consumer 240 and the vehicle radiator 130 , directly via a third cooling return line 138.3 back into the fuel cell 100 directed.

A method for operating a fuel cell system, in particular for determining a power specification LV , is in 4th - partially with reference to the developments shown in the previous - shown schematically.

After a starting point S0, the state of charge is queried in a first step S1 LZ of the energy storage 300 . This determination can be made by the control device 400 especially via the measuring connection 306 respectively. Then there is a branch V1 a check of the state of charge LZ is greater than a lower state of charge LZL . If this is not the case, the power specification is set in a step S2 LV to the required output PO , especially the actual performance requirement LA customized. In this case, the charge level is sufficient LZ of the energy storage 300 , so the amount of in the energy storage 300 stored energy EM - currently or in a specific, immediately following period - not to provide the required power output PO , especially to meet the momentary Performance requirement LA out. In the event that the state of charge LZ is greater than the lower state of charge LZL , the process flow leads from the first branch V1 to a second branch V2 . In the second branch V2 it is checked whether the requested charge status LZ is less than an upper state of charge LZH . If this is not the case, the power of the fuel cell is reduced in a third step S3 100 or a complete shutdown of the fuel cell 100 by the control device 400 , especially about damage to the energy storage device 300 to be avoided by overloading. In this case, the consumer is supplied - in particular completely - from the energy store 300 . Should be in the second branch V2 it can be determined that the requested state of charge LZ is less than the upper state of charge LZH , an operation of the fuel cell can in a fourth step S4 according to the concept of the invention 100 in an efficiency-improved operation BPA , through a corresponding performance specification LV by the control device 400 respectively.

Through the first branch V1 and the second branch V2 So two conditions are checked to ensure that the state of charge is correct LZ in a range between a lower state of charge LZL and an upper state of charge LZH is because the fuel cell is in operation in this area 100 in efficiency-improved operation BPA is sensibly possible.

In the sense of a control loop, after all steps S2, S3 and S4 there is a return to a return point SR1, from which the first step S1 and then the process sequence described above is carried out again. In the control device 400 that this in 4th carries out the process sequence shown, a corresponding cycle time for the repetition of the process sequence from the return point RF1 which represents an optimal compromise between response time and computing power for the application of the control system.

In 5 a process sequence according to a further preferred embodiment is shown. This can be programmed in the control device 400 are executed. After a starting point S10, in a first step S11, the state of charge is initially set LZ of the energy storage 300 determined. A subsequent second step S12 now takes place - taking into account the determined state of charge LZ - the calculation of an amount of energy required up to a target state ZZ EZZ .

For calculating the amount of energy required EZZ can be a predicted performance profile PLP can be used. The forecasted performance profile PLP can - in the event that the fuel cell system 1000 is used in a drive of a vehicle and the target state ZZ is correspondingly a target position SP is - the one up to the target position SP Distance to be covered in the form of a target route SR consider. In this case, differences in height to be overcome, the expected or maximum permissible speed and / or an expected remaining travel time can advantageously be overcome TV including breaks to improve the calculation of the amount of energy required EZZ must be taken into account.

In other embodiments, for example in those in which the fuel cell system is used to generate electricity and / or to generate heat, the predicted performance profile can also contain a plan with an energy requirement in a prediction period. This energy requirement can be estimated on the basis of empirical values, for example, or it can be calculated using models and in this case forms the required amount of energy EZZ .

In a subsequent branch V11 it is checked whether the state of charge LZ of the energy storage 300 , that is, the one in the energy store 300 stored amount of energy EM is smaller than the amount of energy required to achieve the target state ZZ EZZ . If this is not the case, a third step S13 takes place by means of a corresponding output specification LV an operation of the fuel cell 100 with a fuel cell power PB which, in particular, do not affect the efficiency-improved operation BPA corresponds to. In particular, the fuel cell performance PB chosen so that the performance specification LV sufficient to generate the required amount of energy EZZ in the expected remaining travel time TV to create. The fuel cell performance PB In this case, it can be set so that the actual power requirement LA is fulfilled. It can also increase fuel cell performance PB also in a regeneration operation BPR assume a higher value at which the fuel cell also has enough power to recharge the energy store 300 produced. The fuel cell performance PB can be above an efficiency-optimized fuel cell output PBO and below the actual power requirement LA lie, in which case the current power requirement LA partly from the energy storage 300 and partly from the fuel cell 100 is fulfilled. This is particularly advantageous in efficiency-improved operation BPA achieved, the reaching of a specific target state ZZ, in particular for a specific trip F. expected amount of energy EZZ can be customized as in 8th explained. In such a case, the energy store is emptied 300 similar to an operation of the Fuel cell 100 with optimal fuel cell performance PBO , however - due to the higher performance of the fuel cell - at a slower speed, so that in the battery 300 stored amount of energy EM is still sufficient to reach the target state ZZ.

Should the test in the branch V11 reveal that the state of charge LZ of the battery is greater than or equal to the amount of energy required to achieve the target state ZZ EZZ is, the fuel cell is operated in a step S14 100 according to the in 5 procedural sequence shown. Provided the state of charge LZ is greater than the lower state of charge LZL , the fuel cell is operated 100 particularly advantageous in an efficiency-improved operation BPA , by corresponding performance specification LV the control device 400 .

In other developments it is also possible that instead of an energy comparison in branching V11 a performance comparison is made. For this purpose, the amount of energy determined in step S12 EZZ by the expected remaining driving time TV divided in order to determine a power that has to be provided on average by the fuel cell system as output power. Depending on the state of charge LZ an adjustment amount can be made on this basis PAN can be determined by the fuel cell performance PB can be reduced in order to achieve an improved degree of efficiency, while the average output power to be achieved is provided.

In 6th is an embodiment of a control device 400 shown in detail. The control device 400 includes a forward-looking observer 420 , which is formed, a required amount of energy EZZ based on a forecast performance profile PLP to calculate. The forecasted performance profile PLP can especially in the case that the fuel cell system 1000 is used in a vehicle as a predicted driving profile PFP be trained. The predicted performance profile may well be PLP vary depending on the area of application of the fuel cell system. It is thus possible for the fuel cell system to be used in other areas, for example to generate electricity or in an air conditioning unit.

The forecasted performance profile PLP is generated by a profile generator 422 generated based on target data SD , for example one from a navigation device 450 generated target route SR including route and height profiles, of others, in particular of a profile memory 460 profile data provided PD , such as user profiles PN , Vehicle profiles PF , Machine profiles PM and the like profile data, as well as from a measuring unit 440 actual data provided ID such as an actual position IP , Weather data WD and environmental data UD the forecasted performance profile PLP calculated. The one from the measuring unit 440 The actual data provided do not necessarily have to be determined via a sensor, but can, for example, also be made available via a service, for example a web service for weather data. When calculating the forecast performance profile PLP it is calculated with what probable power in what time a target state ZZ, in particular a target position SP , can be reached. In the event that the fuel cell system 1000 is used in a vehicle, is used in the profile generator 422 calculates the expected drive power with which a target position is calculated, taking into account all relevant circumstances SP a target route SR can be reached. The target route SR also in individual target route segments SRS and the calculation for each individual target route segment SRS each with a segment target position SSP be performed. The determination of the forecasted performance profile PLP is therefore particularly suitable for applications in which the expected operation and the associated operating conditions can be foreseen, in particular have a repetitive pattern. This is especially the case when the fuel cell system 1000 with as drive 202 educated consumer 200 is used in a vehicle operating in the planned operation, such as a train, a mine truck, or a liner.

Specific target data and specific actual data can also be provided from a single device, for example the navigation device.

Based on the forecast performance profile PLP is then used in an energy determination unit 424 the total amount of energy EZZ calculated to meet the forecast performance profile PLP is needed. In particular, the calculation of the amount of energy EZZ when looking at the predicted performance profile PLP viewed as a curve of the required power plotted over time, can be formed by integrating this curve over the entire period.

Based on the amount of energy EZZ and via the exhibition entrance 404 transmitted state of charge LZ is in a default unit 426 a performance target LV for the fuel cell 100 calculated and via the control input 110 transmitted to this so that the fuel cell 100 with a fuel cell output that meets the requirements PB , for example in an efficiency-improved operation BPA with a reduced fuel cell performance PA , or an efficiency-optimized operation BPO with an efficiency-optimized fuel cell performance PBO can be operated. An efficiency curve can be used for this KL with the course of the degree of efficiency Flat share a fuel cell 100 serve as they do in 7th is shown - ie the course of the degree of efficiency is plotted Flat share about the fuel cell performance BP , in this case as a relative nominal output PREL on the x-axis in percent.

Furthermore, the present embodiment of the control device 400 a control signal generator 428 on which the control input 402 transmitted performance requirement LA into a control signal RS , especially a drive signal AS converts and this via the control output 408 and then the control connection 208 of the consumer 200 transmitted.

7th shows a schematic representation of the efficiency curve KL with the course of the degree of efficiency Flat share a fuel cell 100 , plotted against the fuel cell output BP , in this case as a relative nominal output PREL on the x-axis in percent. It can be seen that already at approx. 10% of the relative nominal power PREL the efficiency Flat share its maximum - as optimal WGO efficiency at a value of approx. 0.65 - has. This is where the optimal efficiency of the fuel cell can be found PBO for an operation that is optimal in terms of efficiency BPO ; this efficiency-optimized fuel cell performance PBO is comparatively low at approx. 10% of the relative nominal power PREL

To a larger relative nominal power PREL the efficiency decreases Flat share but from; at 100% of the relative nominal power PREL is the value of the efficiency Flat share on the other hand at only approx. 0.4. 100% of the relative nominal power PREL are used here as the starting fuel cell power PK for a power-nominal fuel cell power PBK in the case of an operation with nominal performance BPK - This means that based on the efficiency-optimized fuel cell performance PBO Although the output power of the fuel cell increases, its efficiency decreases; ie the value of the efficiency Flat share decreases.

The present is for a performance specification LV one against 100% of the relative nominal power PREL , ie compared to the full value of the relative nominal power PREL , reduced fuel cell performance PA for an operation that is improved in terms of efficiency BPA at 60% of the relative nominal power PREL for a performance specification LV drawn in as an example. The relative nominal power compared to the full (100%) PREL reduced fuel cell performance PA is therefore an adjustment amount PAN of 40% of an initial fuel cell output PK - here corresponding to 100% of the relative nominal power PREL - Reduced in order to achieve an improved efficiency according to the concept of the invention.

Should the state of charge LZ in this case even higher, the reduced fuel cell output could be PA for a performance specification LV be correspondingly lower compared to the full (100%) relative nominal output PREL , especially again lower than the current performance (<100% PREL ), in favor of a higher degree of efficiency or even higher degree of efficiency Flat share , since in this case a larger or even larger proportion could be taken from the energy store to provide the power output. The adjustment amount PAN in this case would be even higher compared to the aforementioned adjustment amount of 40% for a performance specification LV at 60% of the relative nominal power PREL . In short, this means that for an efficiency-improved operation BPA the performance target LV takes place in such a way that as possible -dh depending on the state of charge LZ of the energy storage 300 - the efficiency ( Flat share ) is increased accordingly compared to the efficiency at nominal power PREL or the current efficiency. For improved efficiency BPA gives the performance specification LV So if possible -dependent on the state of charge LZ of the energy storage 300 - reduced fuel cell performance PA before that of an increased efficiency Flat share corresponds according to the values given for the efficiency Flat share , especially as a characteristic KL , depending on the fuel cell performance PB . In operation and thus in the context of the control, there is in particular the performance specification LV if possible one compared to the full (100%) relative nominal output PREL or current output, reduced fuel cell output PA such before that the efficiency Flat share according to the values is increased compared to the efficiency at nominal power PREL or the current efficiency.

8th shows a schematic profile of a state of charge LZ over different time intervals TI and operating phases. Reference is made here to an application of a fuel cell system as an example 1000 taken according to the concept of the invention in a vehicle not shown in detail. The consumer 200 is therefore considered an electric drive 202 educated.

In a first time interval TI1, the vehicle is initially in a state of rest P , and the charge level LZ is equal to the upper state of charge LZH ; the fuel cell system 1000 is therefore in an idle operating mode BM0 in which the fuel cell 100 in a resting business BPN no energy generated. The state of charge LZ therefore has a constant profile in the first time interval TI1.

The vehicle then drives a first journey in a second time interval TI2 F1 , wherein in a first operating mode BM1 the fuel cell 100 in an efficiency-optimized operation BPO is operated. Because the power required to drive the vehicle is greater than that of the fuel cell 100 generated power, the state of charge increases in this second time interval TI2 LZ up to the target state ZZ1 of the journey F1 in the form of the target position SP1 , continuously. The progress of the state of charge LZ is in 8th shown in a highly simplified linear manner. The slope of the progression of the state of charge LZ thus represents the power balance of the fuel cell 100 and the consumer 200 represent.

The vehicle is in a subsequent third time interval TI3 after the first trip F1 again in an idle state P . The fuel cell 100 however - in a second operating mode BM2 of the fuel cell system 1000 - continue to operate with optimum efficiency BPO operated until the energy storage 300 back to its upper state of charge LZH has reached.

After reaching the upper charge level LZH becomes the fuel cell system 1000 in a fourth time interval TI4 again in the idle operating mode BM0 operated in which the fuel cell 100 in a dormant operation BPN no electrical energy is generated, and the energy store therefore does not have a maximum state of charge that may be harmful to the energy store LZMAX reached. Consequently, the state of charge LZ a constant curve again in the fourth time interval T4.

A second journey begins in a fifth time interval TI5 F2 of the vehicle, which, due to driving and route conditions, such as differences in altitude, average driving speed, headwind and the like, requires a higher drive power than during the first trip F1 in the second time interval TI2, and thus the fuel cell system 1000 a higher power output PO must provide. In 8th this is simplified by a steeply falling linear course of the state of charge LZ shown. The fuel cell system 1000 is still operated in the first operating mode BM1, in which the fuel cell 100 in the efficiency-optimized operation BPO is located.

Due to the higher drive power required during the second trip F2 is the state of charge LZ of the energy storage 300 before the end of the second trip F2 , namely at the end of the fifth time interval TI5, at its lower state of charge LZL . So that the energy storage 300 not further emptied and in particular no - possibly harmful to the energy storage - minimal state of charge LZMIN reached, the control device 400 the fuel cell during a sixth time period TI6 100 in a third operating mode BM3 in a regeneration mode BPR on a regeneration fuel cell power PBR switched in which the fuel cell 100 produces more power than is required to drive the vehicle, so that the energy storage device goes beyond driving the vehicle 300 while driving F2 can be charged. The regeneration fuel cell performance PBR is thus above the efficiency-optimized fuel cell output PBO . With the regeneration fuel cell performance PBR is the efficiency of the fuel cell 100 not as high as with the optimal efficiency fuel cell output PBO , however, is the absolute electrical output of the fuel cell 100 higher. The energy store is at the end of the sixth time interval TI6 300 again up to the upper state of charge LZH loaded. The second trip F2 is also at this point in time when the target state ZZ2 is reached in the form of the target position SP2 completed.

In a seventh time interval TI7 there are three different possible operating modes BM of the fuel cell system 1000 in a different company BP the fuel cell 100 shown comparatively. The basis is a comparison drive F2 ' that have the same trip and route conditions as the second trip F2 subject. For the entire comparison drive F2 ' becomes an amount of energy EZZ for an expected remaining driving time TV needed. The amount of energy EZZ corresponds to each of the three operating modes BM the area under the respective course of the state of charge LZ in the sense of an integral. Would the comparison drive F2 ' in idle operating mode BM0 operated in which the fuel cell 100 in their idle mode BPN would be the state of charge LZ the lower state of charge already at a point in time T7.1 LZL to reach. The fuel cell system 1000 would therefore have to switch to the third operating mode BM3, in which the fuel cell, so that the vehicle can continue to drive, for example, as in the sixth time interval TI6 100 in the regeneration mode BPR is operated.

Even in the first operating mode BM1, in which the fuel cell 100 in optimal efficiency operation BPO is the amount of energy required EZZ still too big to make the comparison trip F2 ' completely with the capacity of the energy store 300 to accomplish. Here, too, the state of charge reaches LZ the battery 300 before the end of the comparison drive F2 ' the lower state of charge at a point in time T7.2 LZL . Analogous to the previous one An example would also have to be the operating mode in order to continue the journey BM be changed accordingly.

An improved approach, just like the one in 5 is described here in 9 shown in a fourth operating mode BM4. In this fourth operating mode BM4, the comparison travel is started F2 ' a predicted performance profile based on the knowledge of the upcoming trip (in particular based on data from a navigation device of the vehicle) PLP that takes into account all relevant, expected driving and route conditions. On the basis of the forecast performance profile PLP can - optionally taking into account a certain additional amount of energy EZZS as a safety buffer - the required amount of energy EZZ must be estimated in advance.

By knowing about the for the comparison drive F2 ' - To reach the target state ZZ2 'in the form of the target position SP2 ' - amount of energy required EZZ can now the control device 400 reduced fuel cell performance PA for improved efficiency BPA the fuel cell 100 be determined by the capacity of the battery here 302 trained energy storage 300 - especially taking into account the current state of charge LZ - suffices with sufficient accuracy. Even if with this reduced fuel cell performance PA the fuel cell 100 is not operated in its optimum efficiency, so the reduced fuel cell performance PA however - under these specific conditions - on the characteristic KL closest to the efficiency-optimized fuel cell performance PBO lying fuel cell power PB represent.

In this way, the fuel cell system 1000 thus advantageous in one - for an individual application, here the comparison drive F2 ' - the greatest possible efficiency of the fuel cell 100 operate.

9 shows a vehicle 2000 with a fuel cell system 1000 according to the concept of the invention. The vehicle has four wheels 1010 of which two are visible here. In the present case, each bike is made by a consumer 200 in the form of an electric drive 202 driven. The setpoint generator 500 is present as an accelerator pedal 501 trained, over this is a performance requirement LA to the control device 400 directed. This generates a performance target LV for the fuel cell 100 . The fuel cell 100 is then in a corresponding company BP operated to provide electrical energy for the drives 202 and that as a battery 300 trained energy storage 300 to create.

List of reference symbols

100

Fuel cell

102

Fuel cell stack

104

supply line

106

Storage line

108

Buffer line

110

Control input

124, 124 '

thermal supply line

124A

further thermal supply line

126

thermal storage line

128

thermal buffer line

130

Vehicle cooler

132

Cooling pipe

134

Cooling medium

136

Soft

138

Cooling return line

138.1, 138.2,

first to third cooling return line

138.3 140

Delivery connection

150

thermal discharge connection

200

consumer

201

electrical consumer

202

electric drive

208

Control connection

240

thermal consumer

242

Air conditioner

244

heater

246

Chiller

248

Consumer control connection

250

Main heat exchanger

252

Unit heat exchanger

254

air conditioning

260

Main circuit

262

Device circuit

264

Cold air duct

300

Energy storage

302

battery

304

Heat storage

306

Measuring connection

326

Storage measurement connection

400, 400 ',

Control device

400 '' 402

Control input

404

Fair input

406

Control output

408

Control output

410

second control input

420

Forward-looking observer, forecasting unit

422

Profile generator

424

Energy determination unit

426

Default unit

428

Control signal generator

440

Measuring unit

450

navigation device

460

Profile memory

500

Setpoint generator

501

accelerator

502

Automated speed controller

521

thermostat

522

Air conditioning control device

1000, 1000 ',

Fuel cell system

1000 "1010

wheel

2000

vehicle

3000.3000 '

Climate system

AIR

air

AIRRES

Residual air

AS

Drive signal

BM

operation mode

BM0

Idle operating mode

BM1-4

first to fourth operating mode

BP

Operation of the fuel cell

BPA

efficiency-improved operation

BPN

Idle mode

BPO

efficiency-optimized operation

BPK

performance nominal operation

BPR

Regeneration operation

D.

drive

E.

Energy, amount of energy generated by the fuel cell

EE

electrical energy, amount of electrical energy

EM

Amount of energy stored in the energy store, amount of stored energy

EMT

thermal amount of storage energy

ET

thermal amount of energy

IT

Energy storage

EZZ

Amount of energy required to achieve a target state, energy horizon

F.

journey

F1, F2

first, second trip

F2 '

Comparison trip

H2

hydrogen

H20

water

HZ

heater

ID

Actual date, actual dates

IP

Actual position

KL

Efficiency curve

KM

Chiller

LA

Performance requirement

LV

Performance specification

LZ

State of charge

LZT

thermal state of charge

LZH

upper state of charge

LZL

lower charge level

LZMAX

Maximum charge level

LZMIN

Minimum charge level

02

oxygen

P

Hibernation

P1, P2, P3

first to third course setting

PA

reduced fuel cell performance

PAN

Adjustment amount

PB

Fuel cell performance

PBO

Efficiency-optimized fuel cell performance

PBR

Regeneration fuel cell performance

PBT

thermal fuel cell performance

PD

Profile date, profile data

PF

Vehicle profile

PFP

Predicted driving profile

PLP

Predicted performance profile

PK

Output fuel cell power

PBK

power-nominal fuel cell power

PM

Machine profile

PN

User profile

PO

Power output

PS

Memory performance

PST

thermal storage capacity

PT

thermal power output

PREL

Relative nominal power

RF1

Return point

RS

Control signal

S1 - S4

first to fourth step of the first process sequence

S11 - S14

first to fourth step of the second process sequence

SD

Target date, target data

SP

Target position

SP1, SP2, SP2 '

first, second target position

SR

Target route

SRS

Target route segment

SSP

Target segment position

T

time

TI

Time interval

TI1 - TI7

first to seventh time interval

TV

expected remaining driving time

UD

Environmental data

V1, V2

first, second branch of the first process sequence

V11

Branch of the second process sequence

WD

Weather date, weather data

Flat share

Efficiency

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 2491612 B1 [0004]

Claims (27)

Fuel cell system (1000, 1000 ', 1000 ") for providing a power output (PO), comprising: - a fuel cell (100) for generating an amount of energy (E, EE, ET) for the power output (PO) and - an energy store (300) for storing the amount of energy (E, EE, ET), a control device (400, 400 ', 400 ") for controlling the fuel cell (100), which is designed to provide a power specification (LV) for the fuel cell (100) for controlling the power output (PO), wherein - the fuel cell (100) is assigned an efficiency (WG) as a function of a fuel cell output (PB), characterized in that - for an efficiency-improved operation (BPA) the output specification (LV) is dependent on State of charge (LZ) of the energy store (300). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 1 , characterized in that for the control device (400, 400 ', 400 ") value specifications for the efficiency (WG), in particular as a characteristic curve (KL), are provided as a function of the fuel cell output (PB). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 1 or 2 , characterized in that for the efficiency-improved operation (BPA) the power specification (LV) specifies a reduced fuel cell power (PA), which corresponds to an increased efficiency (WG) according to the values, in particular the power specification (LV) compared to the full (100%) relative nominal power (PREL) or current (<100% PREL) power reduced fuel cell power (PA) so that the efficiency (WG) is increased according to the values compared to the efficiency at nominal power (PREL) or the current efficiency. Fuel cell system (1000, 1000 ', 1000 ") according to Claim 3 , characterized in that an adjustment amount (PAN) of the reduced fuel cell power (PA) is dependent on the state of charge (LZ) of the energy store (300). Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the output specification (LV) for the efficiency-improved operation (BPA) is determined when the state of charge (LZ) of the energy store (300) is above a lower state of charge (LZL) and / or below an upper state of charge (LZH). Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the control device (400, 400', 400") is designed to accept a power request (LA) during operation. Fuel cell system (1000, 1000 ', 1000 ") according to Claim 6 , characterized in that the output specification (LV) for the efficiency-improved operation (BPA) takes place as a function of a state of charge (LZ) of the energy store (300) in such a way that the power output (PO) corresponds to the power requirement (LA). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 6 or 7th , characterized in that the determination of the output specification (LV) for the efficiency-improved operation (BPA) takes place in such a way that the performance requirement (LA) results from the output specification (LV) and the state of charge (LZ) of the energy store (300). Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the determination of the output specification (LV) for the efficiency-improved operation (BPA) takes place in such a way that a target required to achieve a target state (ZZ) Amount of energy (EZZ) for a forecast period (TP) in the future from the output specification (LV) and the state of charge (LZ) of the energy store (300). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 9 , characterized in that the power specification (LV) is determined in such a way that the target amount of energy (EZZ) is determined as a function of a predicted power profile (PLP), in particular a predicted driving profile (PFP). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 7 , characterized in that the performance specification (LV) is determined in such a way that the predicted performance profile (PLP) is based on one or more actual data (ID), in particular an actual position (IP), and one or more target data (SD), in particular one or more target positions (SP) or segment target positions (SSP), is calculated. Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the consumer (200) is an electric drive (202) and the energy store (300) is a battery (302). Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the fuel cell system (1000, 1000 ', 1000 ") is designed to provide a thermal power output (PT). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 7 , characterized in that the control device (400, 400 ', 400 ") is designed to accept a further performance requirement in the form of a thermal performance requirement (LAT) and to determine the performance specification (LV) as a function of the thermal performance requirement (LAT). Fuel cell system (1000, 1000 ', 1000 ") according to Claim 7 or 8th , further comprising an energy store (300) designed as a heat store (304). Fuel cell system (1000, 1000 ', 1000 ") according to one of the preceding claims, characterized in that the control device (400, 400', 400") is designed, the output specification (LV) preferably in a range between 5% and 15%, particularly preferably at 10% of the fuel cell power (PB). Method for operating a fuel cell system (1000, 1000 ', 1000 "), in particular a fuel cell system (1000, 1000', 1000") for providing a power output (PO) according to one of the Claims 1 to 16 , wherein the fuel cell system has: - a fuel cell (100) for generating an amount of energy (E, EE, EM, ET) for the power output (PO) and an energy store (300) for storing the amount of energy (E, EE, ET), a control device (400, 400 ', 400 ") which is designed in an operation to control the fuel cell (100), wherein - the fuel cell (100) is assigned an efficiency (WG) as a function of a fuel cell output (PB), and the method comprises the step of: - specifying a power specification (LV) for the fuel cell (100) for controlling the power output (PO), characterized in that - for an efficiency-improved operation (BPA) the power specification (LV) is dependent on the state of charge (LZ) of the energy store (300) takes place. Procedure according to Claim 17 , characterized in that for the control device (400, 400 ', 400 ") value information on the efficiency (WG), in particular as a characteristic curve (KL), depending on the fuel cell output (PB) is provided. Fuel cell system (1000, 1000 ', 1000 ") according to Claim 1 or 2 , characterized in that for the efficiency-improved operation (BPA) the power specification (LV) specifies a reduced fuel cell power (PA), which corresponds to an increased efficiency (WG) according to the values, in particular the power specification (LV) compared to the full (100%) relative nominal power (PREL) or current (<100% PREL) power reduced fuel cell power (PA) so that the efficiency (WG) is increased according to the values compared to the efficiency at nominal power (PREL) or the current efficiency. Fuel cell system (1000, 1000 ', 1000 ") according to Claim 19 , characterized in that an adjustment amount (PAN) of the reduced fuel cell output (PA) is dependent on the state of charge (LZ) of the energy store (300). Method according to one of the Claims 17 to 20th , characterized in that the performance specification (LV) is determined as a function of the performance requirement (LA). Method according to one of the Claims 17 to 21 , characterized in that the performance specification (LV) is determined that a target amount of energy (EZZ) required to achieve a target state (ZZ) is met for a forecast period (TP) in the future. Method according to one of the Claims 17 to 22nd , characterized in that the target amount of energy (EZZ) is determined as a function of a predicted performance profile (PLP), in particular a predicted driving profile (PFP). Method according to one of the Claims 17 to 23 , characterized in that the predicted performance profile (PLP) is based on one or more actual data (ID), in particular an actual position (IP), and one or more target data (SD), in particular one or more target positions (SP) or segment target positions (SSP), is calculated. Vehicle (2000) with a fuel cell system (1000, 1000 ', 1000 ") according to one of the Claims 1 to 16 and a consumer (200) designed as an electric drive (202). Vehicle (2000) according to Claim 25 , further comprising a thermal collector (240). Air conditioning system (3000) with a fuel cell system (1000, 1000 ', 1000 ") according to one of the Claims 1 to 16 and a thermal pickup (240).

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