DE102023116840A1 - Method for heating a fuel cell system, fuel cell system, computer program product, computer-readable medium and data carrier signal - Google Patents

Abstract

The present invention relates to a method for heating up a fuel cell system (100) during a cold start or frost start, wherein the fuel cell system (100) has a fuel cell stack (10), an electrical energy interface (200), a cathode gas path (20) for supplying the fuel cell stack (10) with a cathode gas, and at least one electrical auxiliary consumer (90), wherein the method comprises the steps of monitoring (420) an electrical demand system power (Pcharge_max*) requested at the electrical energy interface (200), checking (440) the fuel cell stack (10) for a first operating point with a predetermined target current (iStck*) and a predetermined target voltage (UStck*), wherein the fuel cell stack (10) provides an actual electrical stack power (PStack), and checking (460) at least the cathode gas compressor (21) at least as a function of the monitored, requested electrical Demand system power (PCharge_max*) such that the actual electrical stack power (PStack) provided by the fuel cell stack (10) controlled at the first operating point is divided into the requested electrical demand system power (Pcharge_max*), a cathode gas compressor power (Pcmpr) and an auxiliary consumer power (Paux).

Description

The present invention relates to a method for heating a fuel cell system, a fuel cell system, a computer program product, a computer-readable medium and a data carrier signal.

When operating fuel cells or a fuel cell stack, cold starts (starting at an ambient temperature of 0 °C to 25 °C) and frost starts (starting at an ambient temperature below 0 °C) can be problematic. The fuel cell system can therefore operate less efficiently at low temperatures. For this reason, there is a need, among other things, to bring the fuel cell system up to an operating temperature as quickly as possible at which the system has a particularly high level of efficiency. Furthermore, the charging limit of a vehicle battery that is electrically connected to the fuel cell stack can be limited or "closed" at ambient temperatures below 25 °C and the battery can therefore only be charged to a limited extent, i.e. with low currents or low power.

It is the object of the present invention to at least partially remedy the disadvantages described above. In particular, it is the object of the present invention to provide a method or a fuel cell system in which heating of a fuel cell system takes place particularly easily and/or particularly quickly, in particular taking into account a charging limit of an electrical energy storage device.

The above object is achieved by a method with the features of claim 1 and a fuel cell system with the features of claim 8 as well as a computer program product, a computer-readable medium and a data carrier signal with the features of claim 9, 10 and 11 respectively. Further features and details of the invention emerge from the subclaims, the description and the drawings. Features and details that are described in connection with the method according to the invention naturally also apply in connection with the fuel cell system according to the invention and/or the computer program product and/or the computer-readable medium and/or the data carrier signal and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made mutually.

According to a first aspect, the present invention shows a method, in particular a computer-implemented method, for heating up a fuel cell system, in particular during a frost start and/or a cold start, wherein the fuel cell system has a fuel cell stack. The fuel cell system also comprises an electrical energy interface for transmitting at least part of an electrical energy generated by the fuel cell stack at least to an electrical energy storage device. The fuel cell system also comprises a cathode gas path for supplying the fuel cell stack with a cathode gas, wherein a cathode gas compressor is arranged fluidically in the cathode gas path. The fuel cell system also comprises at least one electrical auxiliary consumer or several electrical auxiliary consumers for the operation of the fuel cell system. The method comprises as a step monitoring an electrical demand system power requested at the electrical energy interface. The method also comprises as a step controlling, in particular regulating, the fuel cell stack to a first operating point with a predetermined target current and a predetermined target voltage, wherein the fuel cell stack provides an actual electrical stack power. The method further comprises, in particular as a step, controlling, in particular regulating, at least the cathode gas compressor at least as a function of the monitored, requested electrical demand system power such that the actual electrical stack power provided by the fuel cell stack controlled at the first operating point is divided at least between the requested electrical demand system power, a cathode gas compressor power of the cathode gas compressor and an auxiliary consumer power of the at least one electrical auxiliary consumer, wherein preferably the actual electrical stack power provided by the fuel cell stack controlled at the first operating point is only divided between the requested electrical demand system power, the cathode gas compressor power of the cathode gas compressor and the auxiliary consumer power of the at least one electrical auxiliary consumer.

The process steps described above and below can, if technically reasonable, be carried out individually, together, once, several times, in parallel and/or one after the other in any order.

The fuel cell stack may be a polymer electrolyte membrane fuel cell stack (PEM fuel cell stack).

A cold start is defined as starting or starting up the fuel cell system at an ambient temperature of 0 °C to 25 °C. Frost start is understood to mean starting or starting up the fuel cell system at an ambient temperature below 0 °C.

The electrical energy interface is in particular an electrotechnical interface of the fuel cell system for transmitting at least part of the electrical energy generated by the fuel cell stack or for providing at least part of the electrical (actual) stack power provided by the fuel cell stack to an external system arranged “outside” the fuel cell system, wherein the external system comprises, for example, an electrical energy storage device. In particular, the fuel cell system comprises only a single electrical energy interface for transmitting at least part of the electrical energy generated by the fuel cell stack to an external system arranged “outside” the fuel cell system. The “remaining” part of the electrical energy generated by the fuel cell stack or the (actual) stack power provided is consumed in particular by the fuel cell system itself. The transmission of at least part of the electrical energy generated by the fuel cell stack can take place with the aid of a DC converter. The electrical energy storage device can also be understood as an electrochemical energy storage device, in particular as a battery. The battery can be a high-voltage battery of a vehicle. The requested electrical demand system power can be understood as an electrical power requested by the external system from the fuel cell stack system.

Controlling the fuel cell stack to the first operating point with the specified target current and the specified target voltage can be understood as regulating the fuel cell stack. Controlling at least the cathode gas compressor at least as a function of the monitored, requested electrical demand system power in such a way that the actual electrical stack power provided by the fuel cell stack controlled to the first operating point is divided between the requested electrical demand system power, the cathode gas compressor power of the cathode gas compressor and the auxiliary consumer power can also be understood as regulating the cathode gas compressor.

In particular, the first operating point with the specified target current and the specified target voltage can be specified or determined depending on an outside temperature and/or a charging limit of the electrical energy storage device and/or the requested electrical system power. The outside temperature can also be understood as the ambient temperature, e.g. of the fuel cell system or a vehicle.

By controlling, in particular controlling and maintaining, the fuel cell stack at the first operating point with the specified target current and the specified target voltage, the fuel cell stack can be heated up independently of the electrical demand system power requested at the electrical energy interface, in particular it can be heated up evenly and/or particularly quickly. The actual electrical stack power provided by the fuel cell stack controlled at the first operating point is divided between the requested electrical demand system power, the cathode gas compressor power of the cathode gas compressor and an auxiliary consumer power of the at least one electrical auxiliary consumer, whereby in particular in the event of a change, e.g. an increase, in the requested electrical demand system power, only the cathode gas compressor power or the cathode gas compressor power and the auxiliary consumer power are adjusted. The cathode gas compressor can thus act as a (positive and/or negative) power buffer. Advantageously, a large power range can be buffered particularly easily with the cathode gas compressor. Furthermore, no more electrical power is provided at the electrical energy interface than is required (required electrical demand system power) and a charging limit of the electrical energy storage device is taken into account, so that the service life of the electrical energy storage device can be particularly long.

It can be advantageous in a method according to the invention that the first operating point of the fuel cell stack is an operating point of the fuel cell stack at which the heat output of the fuel cell stack is greater than the actual electrical stack output provided. The fuel cell stack can thus be heated up particularly quickly and the actual electrical stack output provided by the fuel cell stack and to be "distributed" can be kept particularly low during a cold start or frost start. It can also be advantageous in a method according to the invention that the fuel cell stack has a large number of fuel cells arranged next to one another, wherein the target voltage of the first operating point of the fuel cell stack, in particular of a PEM fuel cell stack, is or will be specified in such a way that the large number of fuel cells of the fuel cell stack, in particular of the PEM Fuel cell stack, each have a voltage between 0.2 and 0.4 volts, preferably a voltage between 0.2 and 0.3 volts. The thermal output of a PEM fuel cell stack can thus be particularly high and the actual electrical stack output provided by the PEM fuel cell stack can be kept particularly low. The heating time of the fuel cell stack can thus be kept particularly short.

It can be advantageous in a method according to the invention that at least one cathode gas valve for controlling a flow of the cathode gas is arranged fluidically in the cathode gas path of the fuel cell system, wherein the cathode gas compressor is controlled at least in cooperation with the at least one cathode gas valve at least as a function of the monitored, requested electrical demand system power in such a way that the actual electrical stack power provided by the fuel cell stack is divided between the requested electrical demand system power, the cathode gas compressor power and the auxiliary consumer power. The fuel cell stack can thus be kept particularly easily at the first operating point with a changing requested electrical demand system power. If the requested electrical system power increases over time, for example due to an expanded charging limit of the electrical energy storage device, the cathode gas compressor can be controlled in such a way that its speed is reduced, with the position of the cathode gas valve also being changed. The cathode gas valve is arranged in particular in fluid terms between the cathode gas compressor and a cathode gas inlet of the fuel cell stack. In a method according to the invention, it can be advantageous that the target current of the fuel cell stack is regulated to the first operating point using the cathode gas valve. In particular, a change in the position of the cathode gas valve changes the air flow of the cathode gas and ensures a voltage increase or a voltage drop in the fuel cell stack, with a DC converter of the fuel cell system adjusting the actual current of the DC converter or the fuel cell stack based on the control target of the target voltage of the fuel cell stack. In other words, the cathode gas valve has the particular task of regulating the current provided by the DC converter to the target current of the fuel cell stack at the (first) operating point. This makes it particularly easy to ensure that the fuel cell stack is depleted of air and to maintain a specific target air stoichiometry, e.g. of approximately λ=1.

In a method according to the invention, it can be advantageous for the fuel cell system to have a plurality of auxiliary electrical consumers, whereby none of the plurality of auxiliary electrical consumers is a passive power sink. Due to the power buffering by the cathode gas compressor, a passive power sink, for example a heating element dedicated to heating, can be omitted. The fuel cell system can thus be designed to be particularly simple. Furthermore, the at least one auxiliary electrical consumer or the plurality of auxiliary electrical consumers for the operation of the fuel cell system can be a sensor for detecting a physical quantity of the fuel cell system, for example a temperature sensor, a pressure sensor, etc., and/or an actuator for changing a physical quantity in the fuel cell system, for example a cooling fluid conveyor arranged fluidically in a cooling fluid path of the fuel cell system for controlling the temperature of the fuel cell stack, and/or a control device for controlling at least the fuel cell system.

In a method according to the invention, it can be advantageous that at least the cathode gas compressor power of the cathode gas compressor is reduced when the requested electrical demand system power at the electrical energy interface increases and/or that at least the cathode gas compressor power of the cathode gas compressor is increased when the requested electrical demand system power at the electrical energy interface decreases. A change in the requested electrical demand system power at the electrical energy interface can thus be counteracted particularly easily and the fuel cell stack can be kept at the first operating point.

According to a second aspect, the present invention shows a fuel cell system, wherein the fuel cell system is electrically connected to an electrical energy storage device via an electrical energy interface. The fuel cell system further comprises a fuel cell stack and the electrical energy interface for transmitting at least part of an electrical energy generated by the fuel cell stack at least to the electrical energy storage device. The fuel cell system further comprises a cathode gas path for supplying the fuel cell stack with a cathode gas, wherein at least one cathode gas compressor is arranged fluidically in the cathode gas path. The fuel cell system further comprises at least one electrical auxiliary consumer or several electrical auxiliary consumers for the Operation of the fuel cell system. The fuel cell system further comprises a control device, wherein the control device is at least designed to monitor an electrical demand system power requested at the electrical energy interface and to control the fuel cell system. In particular, the fuel cell system is designed to carry out a method according to the invention.

The fuel cell system can be deployed or used in a vehicle, in particular a motor vehicle, for example a passenger car, a truck or a motorcycle.

Furthermore, the fuel cell system can have a DC converter for transmitting at least part of the electrical energy generated by the fuel cell stack or for providing the electrical system power required at the electrical energy interface. The DC converter can form at least part of the control device of the fuel cell system.

The fuel cell system according to the second aspect of the invention thus has the same advantages as have already been described for the method according to the first aspect of the invention.

According to further aspects, the present invention shows a computer program product, a computer-readable medium and a data carrier signal, wherein the computer program product, the computer-readable medium and the data carrier signal have the same advantages as have already been described for the method according to the first aspect of the invention or the fuel cell system according to the second aspect of the invention or the computer program product or the computer-readable medium or the data carrier signal according to the further aspects of the invention.

The computer program product comprises commands, in particular instructions, wherein the commands, in particular instructions, cause a fuel cell system according to the invention to carry out a method according to the invention. The computer program product can be implemented as a computer-readable instruction code in any suitable programming language such as JAVA, C++, etc., wherein in particular the instruction code of the computer program product can program a computer or other programmable devices such as a control device of a vehicle according to the invention such that the desired functions are carried out.

The computer program product can be implemented either by means of an instruction code, i.e. software (computer program), or by means of one or more special electronic circuits, i.e. in hardware, or in any hybrid form, i.e. by means of software components and hardware components.

The computer program product can be stored on a computer-readable storage medium, for example a volatile or non-volatile memory and/or a processor of the control device.

Furthermore, the computer program product can be provided in a network such as the Internet, from which it can be downloaded by a user if necessary, wherein in particular when downloading the computer program product the data carrier signal transmits the computer program product according to the invention.

Further measures to improve the invention emerge from the following description of some embodiments of the invention, which are shown schematically in the figures. All features and/or advantages arising from the claims, the description or the drawings, including design details, spatial arrangements and method steps, can be essential to the invention both individually and in various combinations. It should be noted that the figures are only descriptive and are not intended to limit the invention in any way.

• 1 ein Verfahren,
• 2 ein Verfahren,
• 3 ein Brennstoffzellensystem, und
• 4 einen Regelkreis.

They show schematically:

• 1 a procedure
• 2 a procedure
• 3 a fuel cell system, and
• 4 a control loop.

In the following figures, identical reference symbols are used for the same technical features even in different embodiments.

1 discloses schematically a method for heating a fuel cell system (100) during a cold start or frost start, wherein the fuel cell system (100) is, for example, as described in 3 described.

The method comprises as a step monitoring (420) an electrical demand system power (P _{Charge_max} *) requested at the electrical energy interface (200). The method further comprises, as a step, checking (440), in particular checking and maintaining (440), the fuel cell stack (10) at a first operating point with a predetermined target current (i _Stck *) and a predetermined target voltage (U _Stck *), wherein the fuel cell stack (10) provides an actual electrical stack power (P _Stack ), and wherein at least the cathode gas compressor (21) is controlled (460) at least as a function of the monitored, requested electrical requirement system power (P _{Charge_max} *) such that the actual electrical stack power (P _Stack ) provided by the fuel cell stack (10) controlled at the first operating point is divided between the requested electrical requirement system power (P _{charge_max*} ), a cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) and an auxiliary consumer power (P _aux ) of the at least one auxiliary electrical consumer (90).

It can be in the 1 It can also be advantageous in the method shown that the first operating point of the fuel cell stack (10) is an operating point of the fuel cell stack (10) at which the thermal output of the fuel cell stack (10) is greater than the actual electrical stack output (P _Stack ) provided. In particular, the fuel cell stack (10) is a PEM fuel cell stack and has a large number of fuel cells arranged next to one another, wherein the target voltage (U _Stck *) of the first operating point of the fuel cell stack (10) is predetermined such that the large number of fuel cells of the fuel cell stack (10) each have a voltage of between 0.2 and 0.4 volts.

It can be in the 1 It may further be advantageous in the method shown that the fuel cell system (10) has a plurality of auxiliary electrical consumers (90), wherein none of the plurality of auxiliary electrical consumers (90) is a passive power sink.

It can be in the 1 It can also be advantageous in the method shown that at least the cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) is reduced when the requested electrical demand system power (P _{Charge_max} *) at the electrical energy interface (200) increases and/or that at least the cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) is increased when the requested electrical demand system power (P _{Charge_max} *) at the electrical energy interface (200) decreases.

2 discloses schematically a further method, in particular as already described 1 is described, wherein the fuel cell system (100) e.g. as described in 3 is designed as described. At least one cathode gas valve (22) for controlling a flow of the cathode gas can be fluidically arranged in the cathode gas path (20) of the fuel cell system (100), wherein the cathode gas compressor (21) is controlled (461) at least in cooperation with the at least one cathode gas valve (22) at least as a function of the monitored, requested electrical requirement system power (P _{Charge_max} *) such that the actual electrical stack power (P _Stack ) provided by the fuel cell stack (10) is divided between the requested electrical requirement system power (P _{Charge_max} *), the cathode gas compressor power (P _cmpr ) and the auxiliary consumer power (P _aux ). The method can comprise, as a further step, in particular as an initial step, a detection (410) of a cold start/frost start, for example based on a determined outside temperature or ambient temperature. It can be used in the 2 The method shown may also be advantageous if the target current (i _Stck *) of the fuel cell stack (10) is regulated to the first operating point using the cathode gas valve (22) (462).

3 schematically discloses a fuel cell system (100, dashed frame), wherein the fuel cell system (100) is electrically connected to an electrical energy store (300) via an electrical energy interface (200) using a DC converter (210) of the electrical fuel cell system (100). In particular, the fuel cell system (100) is designed to carry out or implement a method as described for the other figures. The fuel cell system (100) comprises a cathode gas path (20, solid line) for supplying the fuel cell stack (10) with a cathode gas, wherein at least one cathode gas compressor (21) and one cathode gas valve (22) are fluidically arranged in the cathode gas path (20). The fuel cell system (100) further comprises at least one electrical auxiliary consumer (90) or a plurality of electrical auxiliary consumers (90), for example a cooling fluid conveyor (31) arranged in a cooling fluid path (30, solid line) and/or a control device (91), for operating the fuel cell system (100). The fuel cell system (100) further comprises a fuel cell stack (10) and the electrical energy interface (200) for transmitting at least part of the electrical energy generated by the fuel cell stack (10) at least to the electrical energy storage device (300) of an external system, ie in particular outside the fuel cell system (100), or for providing an electrical demand system power (P _{Charge_max} *) requested by the external system. The "remaining" part of the electrical energy generated by the fuel cell stack (10) or the (actual) stack power provided is consumed in particular by a cathode gas compressor (21) and the at least one electrical auxiliary consumer (90) or the several electrical auxiliary consumers (90) of the fuel cell system (100) itself or is provided to them. The fuel cell system (100) further comprises a control device (91), wherein the control device (91) is at least designed to monitor an electrical demand system power (P _{Charge_max} *) requested at the electrical energy interface (200) and to control the fuel cell system (100), in particular to control the components of the fuel cell system (100), such as the cathode gas compressor (21) and/or the cathode gas valve (22) and/or the DC-DC converter (210) and/or to communicate with them (dash-dot lines).

4 discloses schematically a control circuit for controlling a fuel cell system (100) as used for example in 3 is described, to carry out a method as described, for example, for the other figures. The control circuit comprises a controller 1 (71), a controller 2 (72), a controller 3 (73), a controller 4 (74) and a controller 5 (75). Furthermore, the cathode gas valve (22), the cathode gas compressor (21) and power electronics (211) of the DC converter (210) form respective actuators. In particular, the target current (i _Stck *) of the fuel cell stack (10) is regulated with the cathode gas valve (22).

list of reference symbols

iStck*

target current fuel cell stack

iDCDC*

Target current DC converter (should correspond in particular to the target current of the fuel cell stack)

iDCDC

Actual current DC converter (fuel cell stack)

iq*

(torque-forming) target current cathode gas compressor

IQ

(torque-generating) actual current cathode gas compressor

uq*

target voltage cathode gas compressor

VAT*

target voltage fuel cell stack

VAT

actual voltage of the fuel cell stack

PStack

actual stack performance

PCharge_max*

requirement system performance

Pcmpr

cathode gas compressor performance

Paux

auxiliary consumer power

posnciv*

position specification cathode gas valve

ηDCDC

DC-DC converter efficiency

ωCmpr

speed of cathode gas compressor

ṁAir

air mass flow

10

fuel cell stack

20

cathode gas path

21

cathode gas compressor

22

cathode gas valve

30

cooling fluid path

31

cooling fluid conveyor

71

Controller 1

72

Controller 2

73

controller 3

74

controller 4

75

controller 5

90

secondary consumers

91

control device

100

fuel cell system

200

energy interface

210

DC converter

211

power electronics DC-DC converter

300

energy storage

410

Detecting a cold start/frost start

420

Monitoring a requested system performance

440

Check fuel cell stack for operating point

460

Checking the cathode gas compressor

461

Checking the cathode gas compressor together with cathode gas valve

Claims (11)

Method for heating up a fuel cell system (100) during a cold start or frost start, wherein the fuel cell system (100) comprises: - a fuel cell stack (10), - an electrical energy interface (200) for transmitting at least part of an electrical energy generated by the fuel cell stack (10) at least to one electrical energy storage device (300), - a cathode gas path (20) for supplying the fuel cell stack (10) with a cathode gas, wherein a cathode gas compressor (21) is arranged fluidically in the cathode gas path (20), - at least one electrical auxiliary consumer (90) for operating the fuel cell system (100), and wherein the method comprises: - monitoring (420) an electrical demand system power (P _{charge_max*} ) requested at the electrical energy interface (200), - checking (440) the fuel cell stack (10) for a first operating point with a predetermined target current (i _Stck *) and a predetermined target voltage (U _Stck *), wherein the fuel cell stack (10) provides an actual electrical stack power (P _Stack ), - controlling (460) at least the cathode gas compressor (21) at least as a function of the monitored, requested electrical requirement system power (P _{Charge_max} *) such that the actual electrical stack power (P _Stack ) provided by the fuel cell stack (10) controlled at the first operating point is divided between the requested electrical requirement system power (P _{Charge_max} *), a cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) and an auxiliary consumer power (P _aux ) of the at least one auxiliary electrical consumer (90). procedure according to claim 1 , characterized in that the first operating point of the fuel cell stack (10) is such an operating point of the fuel cell stack (10) at which the thermal output of the fuel cell stack (10) is greater than the actual electrical stack output (P _Stack ) provided. Method according to one of the preceding claims, characterized in that the fuel cell stack (10) has a plurality of fuel cells arranged next to one another, wherein the target voltage (U _Stck *) of the first operating point of the fuel cell stack (10) is predetermined such that the plurality of fuel cells of the fuel cell stack (10) each have a voltage between 0.2 and 0.4 volts. Method according to one of the preceding claims, characterized in that at least one cathode gas valve (22) for controlling a flow of the cathode gas is fluidically arranged in the cathode gas path (20) of the fuel cell system (100), wherein the cathode gas compressor (21) is controlled (461) at least in cooperation with the at least one cathode gas valve (22) at least as a function of the monitored, requested electrical requirement system power (P _{Charge_max} *) in such a way that the actual electrical stack power (P _Stack ) provided by the fuel cell stack (10) is divided between the requested electrical requirement system power (P _{Charge_max} *), the cathode gas compressor power (P _cmpr ) and the auxiliary consumer power (P _aux ). procedure according to claim 4 , characterized in that the target current (i _Stck *) of the fuel cell stack (10) is regulated to the first operating point (462) using the cathode gas valve (22). Method according to one of the preceding claims, characterized in that the fuel cell system (10) has a plurality of auxiliary electrical consumers (90), wherein none of the plurality of auxiliary electrical consumers (90) is a passive power sink. Method according to one of the preceding claims, characterized in that at least the cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) is reduced when the requested electrical demand system power (P _{Charge_max} *) at the electrical energy interface (200) increases and/or that at least the cathode gas compressor power (P _cmpr ) of the cathode gas compressor (21) is increased when the requested electrical demand system power (P _{Charge_max} *) at the electrical energy interface (200) decreases. Fuel cell system (100), wherein the fuel cell system (100) is electrically connected to an electrical energy storage device (300) via an electrical energy interface (200), wherein the fuel cell system (100) comprises: - a fuel cell stack (10), - the electrical energy interface (200) for transmitting at least a portion of an electrical energy generated by the fuel cell stack (10) at least to the electrical energy storage device cher (300), - a cathode gas path (20) for supplying the fuel cell stack (10) with a cathode gas, wherein at least one cathode gas compressor (21) is arranged fluidically in the cathode gas path (20), - at least one electrical auxiliary consumer (90) for operating the fuel cell system (100), - a control device (91), and wherein the control device (91) is at least designed to monitor an electrical demand system power (P _{Charge_max} *) requested at the electrical energy interface (200) and to control the fuel cell system (100), and wherein in particular the fuel cell system (100) is designed to carry out a method according to one of the preceding claims. Computer program product, wherein the computer program product comprises instructions, wherein the instructions cause a fuel cell system (100) to claim 8 a procedure according to a Claims 1 until 7 executes. Computer-readable medium, on which the computer-readable medium the computer program product according to claim 9 is stored. Data carrier signal, wherein the data carrier signal represents the computer program product according to claim 9 transmits.

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