Method for operating a fuel cell, fuel cell, fuel cell system, computer program product and computer-readable storage medium

Abstract

The invention relates to a method for operating a fuel cell (100), comprising: - Calculating a first requirement parameter which, in accordance with an environmental requirement for the fuel cell (100), comprises at least one controller value of a controller of the fuel cell (100), - calculating a lifetime parameter which is at least partially determined by the effect of the controller value on a lifetime of the fuel cell (100), - Setting at least one controller, wherein the at least one controller is set to a controller value based on an operating function that is at least dependent on the requirement parameter and the service life parameter. Furthermore, the invention relates to a fuel cell (100), a fuel cell system (200), a computer program product, and a computer-readable storage medium.

Description

State of the art

[0001] The invention relates to a method for operating a fuel cell, a fuel cell, a fuel cell system, a computer program product and a computer-readable storage medium.

[0002] Fuel cell systems for power generation typically have at least one system controller. This system controller may incorporate partial functions of an energy manager. However, power- or heat-controlled operation is often standard. The energy manager, which can be integrated or separate, regulates both the operation of the fuel cell as an energy generator and the operation of the loads according to economic and / or ecological parameters. Disclosure of the invention

[0003] A method for operating a fuel cell, a fuel cell, a fuel cell system, a computer program product, and a computer-readable storage medium are proposed. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the fuel cell according to the invention and / or in connection with the fuel cell system according to the invention and / or in connection with the computer program product according to the invention and / or in connection with the computer-readable storage medium according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is and can always be made reciprocally.

[0004] According to the invention, a method for operating a fuel cell is provided, comprising: - Calculating a requirement parameter which, in accordance with an environmental requirement for the fuel cell, comprises at least one controller value of a controller of the fuel cell, - Calculating a lifetime parameter which is at least partially determined by the effect of the controller value on a lifetime of the fuel cell, - Setting at least one controller, wherein the setting of the at least one controller to a controller value is carried out on the basis of an operating function which is at least dependent on the requirement parameter and the lifetime parameter.

[0005] The method can be implemented as a computer-implemented method.

[0006] The method steps can be performed at least partially simultaneously and / or sequentially, whereby the sequence of the method steps is not limited by the specified order, so that individual steps can be performed in different orders. Furthermore, individual or all steps can be performed repeatedly.

[0007] In other words, a method for operating a device for generating electricity by means of an electrochemical reaction can be provided in which two different parameters are calculated, wherein one of the two parameters determines a setting value of the fuel cell which reflects an external requirement on the fuel cell and the other parameter quantitatively evaluates the effect of the setting value with regard to the effect on the service life, wherein the setting of the setting value in the fuel cell is carried out using a function which takes both parameters into account.

[0008] A fuel cell can be understood as a device designed to convert the chemical reaction energy of a fuel, in particular a continuously supplied fuel, and an oxidizing agent into electrical energy. The fuel cell according to the invention can be designed, in particular, as a stationary fuel cell. The fuel cell can have a plurality of subcells connected in series, which can, in particular, be arranged in a stack.

[0009] Calculating a requirement parameter can be understood as executing an algorithm, particularly by a computing unit, which, when called, outputs an output value corresponding to the requirement parameter. The output value can depend on the ambient requirement. For example, the ambient requirement could correspond to a requested power output. The requirement parameter could then include, for example, a fuel flow rate and / or a temperature specification for the fuel cell output. It is to be expected that the requested power output will be achieved given these requirement parameters. It can be provided that the requirement parameter is calculated using a model. This achieves particularly precise control of the fuel cell so that the ambient requirement is met.

[0010] The ambient demand can be an external demand from a consumer or, more generally, from a device external to the fuel cell that places a demand on the fuel cell. The ambient demand can be embodied as a requested power and / or requested heat.

[0011] Depending on their design, fuel cells can comprise a multitude of controllers. The controllers can directly control a physical variable, such as the fuel flow into the fuel cell. However, a controller can also control an abstract, particularly higher-level variable, such as the overall temperature of the fuel cell, which can be achieved by adjusting associated controllers (e.g., the temperature at the fuel cell inlet and outlet).

[0012] A controller can be set to a controller value. The controller value can be configured as a setpoint. Each controller value can also be assigned an actual value, which corresponds to the actual current value specified by the controller.

[0013] Calculating a lifetime parameter can be understood as meaning that, in particular, a computing unit executes an algorithm which, when called, outputs an output value corresponding to the lifetime parameter. The output value depends on the effect of the controller value on the lifetime of the fuel cell. For example, the controller value could correspond to a power output, e.g., 1000 W. The lifetime parameter could then include, for example, the expected lifetime of the fuel cell under the set controller value. It is to be expected that the controller value of the controller has an influence on the expected lifetime of the fuel cell. It can be provided that the lifetime parameter is calculated using a model. This achieves a particularly accurate estimate of the lifetime of the fuel cell.

[0014] Adjusting the at least one controller can be understood as setting a target value of a controller of the fuel cell. The controller can be configured to at least partially determine the current output by the fuel cell. Overall, fuel cells offer a multitude of controllable variables, which are generally familiar to those skilled in the art and to which the teachings of the invention are applicable. Adjusting the at least one controller can comprise transmitting a control signal, which can be designed, in particular, to control an actuator such that the controller moves to a position corresponding to the control value.

[0015] The controller value is determined via the operating function, which in turn depends at least on the requirement parameter and the service life parameter. In other words, at least the requirement parameter and the service life parameter are taken into account when calculating the operating function. It can be provided that the requirement parameter or the service life parameter correspond to different controller values. For example, the requirement parameter can take into account that a particularly rapid change in power output is desired, so that the corresponding controller value deviates significantly from the actual value. The service life parameter could then take into account that a rapid change reduces the service life. For optimization for the service life of the fuel cell, a controller value that deviates less from the actual value would then result.In other words, the operational function can be designed to perform a trade-off between the requirement parameter and the lifetime parameter. The operational function can be designed to trade off the requirement parameters and lifetime parameters in the form of costs.

[0016] Such a cost function, which the operating function may have, may in particular be designed as: Costs = operating costs−feed-in tariff−own electricity generation−heat generation+CO2 costs+aging

[0017] The operating costs of a fuel cell can include the fuel consumed and other necessary materials, as well as, in particular, maintenance costs. The feed-in tariff represents a negative cost. Self-generated electricity can also be represented as a negative cost and can, in particular, include the costs that would have been incurred if the fuel cell had not been operated and the electricity had been obtained from another source. Heat generation can also be represented as a negative cost if used appropriately, and includes the costs that would have been incurred if the fuel cell had not been operated and the heat had been obtained from another source. CO2 costs can correspond, in particular, to legally regulated costs that arise from the generation of CO2. They can be represented, for example, as: CO2 costs = CO2 price * gas consumption * emission factor

[0018] The aging of the fuel cell can cause costs in the sense that parts or the fuel cell as a whole must be replaced if they are defective. It can be provided that the aging includes one or more controller values, which are transferred to a cost point in a currency via a factor. The aging function can, in particular, take the form Aging=f1*controller value1+f2 controller value2+…fn*controller valuen It can further be provided that the lifetime parameter corresponds to the aging function.

[0019] The dependence of the operating function on the demand parameter and the lifetime parameter should not be understood to mean that the operating function would necessarily change if only one of the parameters were considered. However, it will often be the case that considering both parameters will lead to a different controller value.

[0020] Overall, the method according to the invention offers the advantage that, in addition to established parameters, at least one further parameter is taken into account to optimize the service life of the fuel cell. This subsequently results in the advantage that cost savings can be achieved through fewer failures and downtimes. Fewer failures and downtimes also increase the comfort and, if applicable, safety for users of the devices connected to the fuel cell. By calculating the requirement parameter, the established parameters are therefore taken into account. Calculating a service life parameter adds a component to the analysis that optimizes the service life of the fuel cell by taking it into account in the operating function.

[0021] Within the scope of the invention, it is conceivable that the lifetime parameter is at least dependent on a load point of the fuel cell, a number of cycles run by the fuel cell, a power gradient of the fuel cell or an output current of the fuel cell.

[0022] The load point of a fuel cell can be understood as an operating point at which the fuel cell achieves a certain power and / or efficiency. Further details regarding the load point will be discussed in further subclaims. Each load point can be associated with a degree of material wear and / or degradation, which influences the service life of the fuel cell.

[0023] The number of cycles performed by a fuel cell can describe how often the fuel cell completes a cycle. Each cycle can result in a certain degree of material wear and / or degradation, which can limit its service life.

[0024] The power gradient of a fuel cell can indicate how rapidly the fuel cell's performance changes when environmental requirements change, for example, when the load and / or energy demand varies. A steep power gradient indicates that the fuel cell is sensitive to changes, while a shallow gradient indicates that performance remains relatively stable even when operating conditions change. In particular, a steep power gradient may be associated with a higher degree of material wear and / or degradation than a shallow one. Therefore, the power gradient can influence the fuel cell's lifetime.

[0025] It can be provided that the lifetime parameter contains at least one term of an aging function of the form f1*current+f2*cycles+f3*power gradient+f4*deviation from load point optimum wherein the current indicates the current provided by the fuel cell, the cycles indicate the number of cycles run by the fuel cell, the power gradient (in particular as described above) is the indication of how quickly the power of the fuel cell changes, and the deviation from the load point optimum indicates the degree to which the current load point deviates from the optimal load point (which is described in more detail below).

[0026] Within the scope of the invention, it can be provided that the service life parameter comprises at least one factor that converts a sensor-detectable measured value into a unit of the operating function. In other words, it can be provided that the service life parameter comprises a value accessible by measuring a physical quantity, such as “X amperes.” This can then be converted into a unit of the operating function. This can, for example, have a unit of a controller value. It can further be provided that the service life parameter is included in the operating function as a cost function. It can then be provided that the sensor-detectable measured value is converted into a cost point using the factor. In the above example, the factor would then have the unit currency / ampere. By converting the measured value into a unit of the operating function, this can be taken into account quickly, efficiently, and reliably.

[0027] It is further conceivable that a determination of a load point of the fuel cell is also provided. The load point can be determined, for example, using at least one voltage-current characteristic curve (also called a UI characteristic curve for short), stored in particular in a memory accessible to the fuel cell's processing unit. It can be provided that the UI characteristic curve is specific to at least one fuel flow. It can be provided that UI characteristic curves are stored for at least two, in particular for a plurality of fuel flows. This allows a load point for the fuel cell to be determined particularly easily and reliably.

[0028] It is also conceivable that an optimal load point of the fuel cell is further determined, wherein in particular the optimal load point is determined at least by a minimized current, a maximized efficiency, and depletion-free operation of the fuel cell. In other words, among the possible load points, there may also be an optimal load point which is particularly advantageous compared to the other load points. A minimized current has the advantage of extending the service life of the fuel cell. A maximized efficiency has the advantage that particularly little energy is wasted. Depletion-free operation prevents damage to the fuel cell which can occur due to operation in depletion (i.e. when the fuel is fully converted before the end of the fuel cell stack has been reached).

[0029] Within the scope of the invention, it may be advantageous for the environmental requirement to include at least a requirement for current output or heat output. In other words, it may be provided that an external device, in particular a consumer, places a requirement on the fuel cell with respect to at least a current, a power output, or a heat quantity. Such a requirement can be implemented particularly easily via the requirement parameter, whereby consideration of the service life parameter ensures that the service life of the fuel cell is not excessively shortened.

[0030] Furthermore, a fuel cell according to the invention, in particular at least comprising a computing unit or a sensor, is proposed, operated according to a method according to the invention.

[0031] Possible embodiments of the fuel cell have already been explained in connection with the method and can also relate to the fuel cell according to the invention and / or the fuel cell system.

[0032] This results in the same advantages with regard to a fuel cell according to the invention as have already been described with regard to a method according to the invention.

[0033] Furthermore, a fuel cell system according to the invention is proposed, comprising at least one fuel cell according to the invention and at least one consumer.

[0034] The fuel cell system may be provided with a computing unit. This may be arranged on the fuel cell, in particular integrated into it, or at a distance from it.

[0035] The consumer can be implemented as a basic electrical consumer in a building or facility, in particular in lighting, electronic devices, heating and cooling systems, pumps, ventilation systems and other electrical machines.

[0036] Furthermore, the consumer can also be designed as a heat consumer. The heat emitted by the fuel cell can be used for heating purposes in buildings or fed into refrigeration systems to generate cold.

[0037] Furthermore, the consumer can also be designed as an emergency power supply, which can be designed in particular as a backup power supply system in the event of a power failure.

[0038] This results in the same advantages with regard to a fuel cell system according to the invention as have already been described with regard to a method according to the invention and / or a fuel cell according to the invention.

[0039] Furthermore, a computer program product according to the invention is proposed, comprising instructions which, when the program is executed by a computer, in particular by a computing unit of a fuel cell according to the invention, cause the computer to carry out a method according to the invention.

[0040] This results in the same advantages with regard to a computer program product according to the invention as have already been described with regard to a method according to the invention and / or a fuel cell according to the invention and / or a fuel cell system according to the invention.

[0041] Furthermore, a computer-readable storage medium is proposed, comprising instructions which, when executed by a computer, in particular by a computing unit of a fuel cell according to the invention, cause the computer to carry out a method according to the invention.

[0042] This results in the same advantages with regard to a computer-readable storage medium according to the invention as have already been described with regard to a method according to the invention and / or a fuel cell according to the invention and / or a fuel cell system according to the invention and / or a computer program product according to the invention.

[0043] Further advantages, features, and details of the invention will become apparent from the following description, which describes several embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination. These schematically show: Fig. 1 a fuel cell and a fuel cell system and Fig. 2 a UI characteristic curve of a fuel cell.

[0044] In the following figures, identical reference numerals are used for the same technical features, even for different embodiments.

[0045] Fig. 1 shows a fuel cell 100 according to the invention in connection with a fuel cell system 200 according to the invention.

[0046] As in the Fig. As can be seen in Figure 1, the fuel cell 100 can have a computing unit 110. Alternatively, it can also be provided (not shown) that the computing unit 110 is part of the fuel cell system 200 and is arranged at a distance from the fuel cell 100. The computing unit 110 can be designed to carry out the inventive method for operating the fuel cell.The method for operating a fuel cell 100 comprises calculating a requirement parameter which, in accordance with an environmental requirement on the fuel cell 100, comprises at least one controller value of a controller of the fuel cell 100, calculating a lifetime parameter which is at least partially determined by the effect of the controller value on a lifetime of the fuel cell 100, and setting the at least one controller, wherein the setting of the at least one controller to a controller value is carried out based on an operating function which is at least dependent on the requirement parameter and the lifetime parameter.

[0047] Overall, the method according to the invention offers the advantage that, in addition to established parameters, at least one further parameter is taken into account, which optimizes the service life of the fuel cell 100. This subsequently results in the advantage that cost savings can be achieved through fewer failures and downtimes. Fewer failures and downtimes also increase the comfort and, if applicable, safety for the users of the devices connected to the fuel cell 100. By calculating the requirement parameter, the established parameters are therefore taken into account. Calculating a service life parameter adds a component to the analysis, which optimizes the service life of the fuel cell 100 by taking it into account in the operating function.

[0048] Furthermore, the Fig. 1 that the fuel cell has at least one sensor 120. The sensor can be designed to detect at least one actual value of a controller and / or a variable associated with the controller. Detecting the actual value of the controller can also be part of the method according to the invention.

[0049] Compared to the fuel cell 100, the fuel cell system 200 is expanded because it includes a consumer 210.

[0050] The consumer 210 can be designed as a basic electrical consumer 210 in a building or the facility, in particular in lighting, electronic devices, heating and cooling systems, pumps, ventilation systems and other electrical machines.

[0051] Furthermore, the consumer 210 can also be designed as a heat consumer. This heat emitted by the fuel cell 100 can be used for heating purposes in buildings or fed into refrigeration systems to generate cold.

[0052] Furthermore, the consumer 210 can also be designed as an emergency power supply, which can be designed in particular as a backup power supply system in the event of a power failure.

[0053] The Fig. Figure 2 shows a UI characteristic curve of a fuel cell 100, with the voltage plotted on the ordinate and the current density on the abscissa. Furthermore, different regions are shown, separated by dashes. From top to bottom, these regions are waste heat, resting overvoltage, breakdown overvoltage, ohmic overvoltage, concentration overvoltage, and (at the very bottom) usable electrical energy. Accordingly, the slightly bolder line marks load points of the fuel cell 100.

[0054] It is conceivable that a determination of a load point of the fuel cell 100 is also provided. The load point can be determined, for example, based on at least one voltage-current characteristic curve (also called a UI characteristic curve for short), stored in particular in a memory accessible to the computing unit 110 of the fuel cell 100. It can be provided that the UI characteristic curve is specific to at least one fuel flow. It can be provided that UI characteristic curves are stored for at least two, in particular for a plurality of fuel flows. This allows a load point for the fuel cell 100 to be determined particularly easily and reliably.

[0055] It is also conceivable that an optimal load point of the fuel cell 100 is further determined, wherein in particular the optimal load point is determined at least by a minimized current, a maximized efficiency, and depletion-free operation of the fuel cell 100. In other words, among the possible load points, there may also be an optimal load point which is particularly advantageous compared to the other load points. A minimized current has the advantage of extending the service life of the fuel cell 100. A maximized efficiency has the advantage that particularly little energy is wasted. Depletion-free operation prevents damage to the fuel cell 100 that could occur due to depletion operation (i.e., when the fuel is fully converted before the end of the fuel cell stack has been reached).

[0056] The load point can be included in the lifetime parameter. It can be provided that the lifetime parameter is at least dependent on a load point of the fuel cell 100, a number of cycles run by the fuel cell 100, a power gradient of the fuel cell 100, or an output current of the fuel cell 100.

[0057] The number of cycles performed by the fuel cell 100 can describe how often the fuel cell 100 completes a cycle. Each cycle can result in a certain degree of material wear and / or degradation, which can limit the service life.

[0058] The power gradient of a fuel cell 100 can indicate how quickly the performance of the fuel cell 100 changes when environmental requirements change, for example, when the load and / or energy demand varies. A steep power gradient indicates that the fuel cell 100 is sensitive to changes, while a shallow gradient indicates that performance remains relatively stable even when operating conditions change. In particular, a steep power gradient may be associated with a higher degree of material wear and / or degradation than a shallow one. As a result, the power gradient can influence the lifetime of the fuel cell 100.

Claims

[1] A method for operating a fuel cell (100), comprising: - Calculating a requirement parameter which, in accordance with an environmental requirement for the fuel cell (100), comprises at least one controller value of a controller of the fuel cell (100), - calculating a lifetime parameter which is at least partially determined by the effect of the controller value on a lifetime of the fuel cell (100), - Setting the at least one controller, wherein the setting of the at least one controller to a controller value is carried out on the basis of an operating function which is at least dependent on the requirement parameter and the service life parameter. [2] Method according to claim 1, characterized bythat the lifetime parameter is at least dependent on a load point of the fuel cell (100), a number of cycles run by the fuel cell (100), a power gradient of the fuel cell (100) or an output current of the fuel cell (100). [3] Method according to claim 1 or 2, characterized by that the lifetime parameter comprises at least one factor which converts a sensor-detectable measured value into a unit of the operating function. [4] Method according to one of the preceding claims, characterized by that a determination of a load point of the fuel cell (100) is further provided. [5] Method according to one of the preceding claims, characterized bythat further provision is made for determining an optimum load point of the fuel cell (100), wherein in particular the optimum load point is determined at least by a minimised current, a maximised efficiency and a depletion-free operation of the fuel cell (100). [6] Method according to one of the preceding claims, characterized by that the environmental requirement includes at least a requirement for power output or heat output. [7] Fuel cell (100), in particular at least comprising a computing unit (110) or a sensor (120), operated according to a method according to one of claims 1 to 6. [8] Fuel cell system (200) comprising at least one fuel cell according to claim 7 and at least one consumer (210). [9] Computer program product, comprising instructions which, when the program is executed by a computer, in particular by a computing unit (110) of a fuel cell (100) according to claim 7, cause the computer to carry out a method according to one of claims 1 to 6. [10] Computer-readable storage medium, comprising instructions which, when executed by a computer, in particular by a computing unit (110) of a fuel cell (100) according to claim 7, cause the computer to carry out a method according to one of claims 1 to 6.

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