Method for operating a cell system having at least one electrochemical cell, cell system and computer program

Abstract

The invention relates to a method for operating a cell system (22) having at least one electrochemical cell (24). It is proposed to adjust at least one operating parameter of the temperature control unit (30) as a function of at least one internal temperature characteristic parameter of the cell system (22).

Description

Technical Field

[0001] A method for operating a cell system having at least one electrochemical cell has been proposed. Summary of the Invention

[0002] The invention relates to a method for operating a cell system having at least one electrochemical cell.

[0003] It is proposed to adjust at least one operating parameter of a temperature control unit of the battery cell system as a function of at least one internal temperature characteristic parameter of the battery cell system.

[0004] The embodiment of the method for operating a battery cell system according to the present invention makes it possible to particularly precisely and efficiently prevent the battery cell system from operating outside a set temperature range. Advantageously, the battery cell system can be operated particularly smoothly. Advantageously, temperature-induced damage to the battery cell system can be particularly effectively and precisely prevented. Advantageously, the battery cell system can be operated particularly efficiently and safely. Advantageously, a particularly durable battery cell system can be provided. Advantageously, the battery cell system can be adjusted particularly dynamically.

[0005] Preferably, the electrochemical cell is designed as a solid oxide fuel cell. However, it is also conceivable as an alternative to design the electrochemical cell as another fuel cell, for example as a polymer electrolyte fuel cell, an electrolyte cell or a storage cell. For example, it is also conceivable as an alternative to use the electrochemical cell in an electrolyzer. It is conceivable that the cell system has only one electrochemical cell, in particular the electrochemical cell mentioned above, or that the cell system has a plurality of electrochemical cells, for example two, three or hundreds of electrochemical cells. Preferably, the electrochemical cells of the cell system having a plurality of electrochemical cells are combined into a stack and in particular connected in series. It is also conceivable that the cell system comprises a plurality of stacks formed by a plurality of electrochemical cells, which stacks are preferably combined into a module or a tower.

[0006] The battery system preferably includes a control unit. The control unit is particularly configured to execute a method for operating the battery system. "Configured" should be understood as specially configured, specially designed and / or specially equipped. The fact that an object is configured for a certain function should be understood as that the object realizes and / or executes this specific function in at least one application state and / or operating state. The control unit particularly includes at least one processor and a storage element and an operating program stored on the storage element. The storage element is preferably configured as a digital storage medium, such as a hard disk or the like. The battery system particularly includes a housing, in which at least one electrochemical cell or a stack formed by a plurality of electrochemical cells is preferably arranged. It is conceivable that the control unit is at least partially arranged on the housing, in particular at least partially arranged in the housing. Alternatively or additionally, it is also conceivable that the battery system has an external unit, wherein the external unit includes at least part of the control unit. The external unit can be, for example, a cloud, a server, etc. It is conceivable that the external unit includes the storage element of the control unit.

[0007] The temperature control unit preferably has at least one fan unit. The temperature control unit, in particular the fan unit, is in particular configured to generate an air volume flow, preferably on the cathode side of the battery cell system. With the aid of the fan unit, preferably with the aid of the air volume flow that can be generated by the fan unit, the oxygen ions required for the electrochemical reaction of the battery cell system (preferably including fuel cells) are provided, in particular. The battery cell system, in particular at least one electrochemical cell or a stack of a plurality of electrochemical cells, is preferably temperature-controlled with the aid of the temperature control unit. The battery cell system, in particular at least one electrochemical cell or a stack of a plurality of electrochemical cells, is in particular cooled or heated with the aid of the temperature control unit. Preferably, the fan unit is configured to generate an air volume flow for cooling the battery cell system, in particular for cooling at least one electrochemical cell or a stack of a plurality of electrochemical cells. Alternatively or additionally, it is conceivable that the fan unit is configured to generate a (preferably preheated) air volume flow for heating the battery cell system, in particular for heating at least one electrochemical cell or a stack of a plurality of electrochemical cells. It is conceivable that the fan unit has one or more fans.

[0008] Alternatively or in addition, it is conceivable that the temperature control unit includes a heating unit for heating the cell system, in particular heating at least one electrochemical cell or a stack formed by a plurality of electrochemical cells, for example for heating the air volume flow that can be generated by the fan unit. The heating unit is preferably designed as an electric heating unit. The heating unit in particular has at least one heating element, preferably an electric heating element. However, it is also conceivable as an alternative to design the heating unit as a fluid-based heating unit, in particular a liquid-based heating unit and / or a gas-based heating unit. The fluid-based heating unit is particularly configured to heat the cell system by means of a fluid, in particular heating at least one electrochemical cell or a stack formed by a plurality of electrochemical cells. The liquid-based heating unit is particularly configured to heat the cell system by means of a liquid (e.g. water, etc.), preferably heating at least one electrochemical cell or a stack formed by a plurality of electrochemical cells. The gas-based heating unit is particularly configured to heat the cell system by means of a gas, preferably heating at least one electrochemical cell or a stack formed by a plurality of electrochemical cells. Furthermore, it is alternatively conceivable that the heating unit is designed as a fluid-based, in particular gas-based, heating unit and / or as a combination of a liquid-based heating unit and an electric heating unit.

[0009] Alternatively or additionally, it is also conceivable that the temperature control unit includes a liquid cooling unit for cooling the cell system, in particular, cooling at least one electrochemical cell or a stack of a plurality of electrochemical cells. The fluid cooling unit is particularly configured to cool the cell system, preferably at least one electrochemical cell or a stack of a plurality of electrochemical cells, using a fluid. The liquid cooling unit is particularly configured to cool the cell system, preferably at least one electrochemical cell or a stack of a plurality of electrochemical cells, using a liquid (e.g., water, etc.). It is conceivable that the liquid cooling unit is at least partially integral with the liquid-based heating unit. "At least one unit and at least one further unit are at least partially integral with one another" is to be understood in particular to mean that at least one element of a unit is integral with at least one further element of a further unit. "Integrally" is to be understood in particular to mean at least materially connected, for example, by welding, adhesive bonding, injection molding, and / or other processes appropriate to a person skilled in the art, and / or advantageously formed in one piece, for example, by casting and / or by single-component or multi-component injection molding, advantageously from a single blank. It is also conceivable that the gas cooling unit is at least partially integrated with the gas-based heating unit. The gas cooling unit is particularly provided for cooling the cell system, preferably at least one electrochemical cell or a stack of a plurality of electrochemical cells, by means of a gas.

[0010] The at least one operating parameter of the temperature control unit may preferably be a heating power of a heating unit (in particular an electric heating unit), a volume flow (in particular a volume flow of a fan unit), a volume flow of a fluid-based heating unit (in particular a volume flow of a liquid-based heating unit), and / or a volume flow of a gas-based heating unit, a volume flow of a fluid cooling unit (preferably a volume flow of a liquid cooling unit and / or a volume flow of a gas cooling unit), etc. In particular, the internal temperature characteristic parameter is a cell characteristic parameter of the cell system, preferably an internal characteristic parameter of the cell system.

[0011] Furthermore, it is proposed to determine the internal temperature characteristic parameter based on a physical model of the battery cell system. In particular, at least one aging characteristic parameter of the battery cell system is determined based on the physical model. Additionally, it is conceivable to determine at least one further battery cell characteristic parameter of the battery cell system based on the physical model, preferably another internal characteristic parameter of the battery cell system. The physical model is preferably a simulation model of the battery cell system, which in particular describes the operation of the battery cell system in a steady state. Preferably, the physical model is based on a finite element method. In particular, the physical model has clear reversibility with respect to the aging characteristic parameter of the battery cell system. It is conceivable that the physical model has clear reversibility with respect to the aging characteristic parameter at least by filtering out physically irrelevant results of the physical model. For example, a physical model according to the publication of Zaccaria, Tucker and Traverso entitled "A distributed real-time model of degradation in a solid oxide fuel cell" (2016, Journal of Power Sources, 311, 175-181) can describe the degradation of a cell system with solid oxide fuel cells, wherein the ohmic component of the internal voltage loss is provided with an aging characteristic parameter as a prefactor. Alternatively, it is also conceivable, for example, that other resistances different from the ohmic component of the internal voltage loss of the cell system (in particular concentration losses or polarization losses) or the total internal resistance of the cell system are multiplied by the aging characteristic parameter as a prefactor. In a preferred physical model, in particular the total specific surface resistance of the cell system is multiplied by the aging characteristic parameter. The aging characteristic parameter is in particular a cell characteristic parameter that describes the cell system. The aging characteristic parameter preferably describes the aging state of the cell system. For example, in the unaged state of the cell system, the aging characteristic parameter has a value of 1, and for the aged state of the cell system preferably has a value greater than 1. The aging characteristic parameter is preferably a scalar. Advantageously, the internal temperature characteristic variable can be determined with particularly low sensor technology expenditure. Advantageously, the internal temperature characteristic variable, which requires particularly high sensor technology expenditure for detection, can be determined particularly simply.

[0012] Furthermore, it is proposed to determine an internal temperature characteristic parameter based on a physical model of the cell system as a function of the cell system's operating parameters, preferably by means of a control unit. Preferably, an aging characteristic parameter is determined based on the physical model as a function of the cell system's operating parameters, preferably by means of a control unit. Additionally, it is conceivable to determine at least one further cell characteristic parameter (in particular, at least one further internal characteristic parameter of the cell system) based on the physical model as a function of the cell system's operating parameters. The physical model in particular has at least one input variable and at least one output variable. Preferably, the at least one input variable of the physical model comprises at least one operating parameter of the cell system, in particular at least one input characteristic parameter of the cell system, preferably at least one operating parameter of the cell system. Preferably, the at least one further input variable of the physical model is an aging characteristic parameter. The cell system's operating parameters are, for example, the queried load current, temperature (in particular, gas temperature), volume flow, air utilization, fuel utilization, gas composition, pressure, differential pressure, etc. Preferably, the at least one output variable of the physical model comprises at least one operating parameter of the cell system, in particular at least one output characteristic parameter of the cell system, preferably at least one performance characteristic parameter of the cell system. The performance characteristic parameter of the cell system is, in particular, the output voltage of an electrochemical cell, preferably the output voltage of a stack formed of a plurality of electrochemical cells. It is conceivable that the output variable of the physical model comprises at least one further cell characteristic parameter of the cell system, in particular at least one further internal characteristic parameter. Preferably, the output variable of the physical model is an internal temperature characteristic parameter. The internal temperature characteristic parameter is preferably the temperature of the cell system, in particular the temperature of at least one electrochemical cell or a stack formed of a plurality of electrochemical cells. The internal temperature characteristic parameter is preferably a local field variable. The at least one further cell characteristic parameter of the cell system (in particular an internal characteristic parameter) is preferably a local field variable, such as a fluid distribution (preferably oxygen distribution or hydrogen distribution) in the cell system, a current density distribution in the cell system, or the like. The physical model is, in particular, a mapping that maps input variables of the physical model (preferably at least one operating parameter of the cell system and an aging characteristic parameter of the cell system) to output variables of the physical model (preferably at least one performance characteristic parameter of the cell system, an internal temperature characteristic parameter, and in particular at least one further cell characteristic parameter of the cell system). Advantageously, the internal temperature characteristic parameter can be determined using characteristic parameters of the cell system that are particularly easily detectable. Advantageously, the internal temperature characteristic variable can be determined with particularly low expenditure in sensor technology as a function of at least one operating parameter of the temperature control unit.

[0013] Furthermore, it is proposed that the characteristic operating parameter comprises at least one (in particular already mentioned) input characteristic parameter of the cell system. It is conceivable that the characteristic operating parameter, from which at least the internal temperature characteristic parameter is determined based on a physical model of the cell system, comprises only one or more input characteristic parameters of the cell system. Advantageously, the internal temperature characteristic parameter, in particular the at least one input characteristic parameter of the cell system, can be determined using particularly easily detectable characteristic parameters of the cell system. Advantageously, the internal temperature characteristic parameter can be determined with particularly low sensor technology expenditure.

[0014] Furthermore, it is proposed that the input characteristic parameter has at least one (in particular already mentioned) operating parameter of the battery cell system. In particular, the input characteristic parameter corresponds to the operating parameter of the battery cell system. It is conceivable that at least one operating parameter of the battery cell system is a control variable or a controlled variable of the battery cell system, in particular an actual value or a target value of the controlled variable. Advantageously, characteristic parameters of the battery cell system that can be detected particularly easily can be used to determine an internal temperature characteristic parameter, in particular at least one operating parameter of the battery cell system. Advantageously, the internal temperature characteristic parameter can be determined with particularly low technical expenditure. Advantageously, for determining the internal temperature characteristic parameter, characteristic parameters of the battery cell system that have already been detected during operation of the battery cell system can be used at least in part.

[0015] Furthermore, it is proposed that the operating characteristic parameter comprises at least one (in particular already mentioned) output characteristic parameter of the battery cell system. It is conceivable that the operating characteristic parameter on the basis of which the internal temperature characteristic parameter is determined based on a physical model of the battery cell system comprises only one output characteristic parameter of the battery cell system or a plurality of output characteristic parameters of the battery cell system. Advantageously, characteristic parameters of the battery cell system that can be detected particularly easily (in particular at least one output characteristic parameter) can be used to determine the internal temperature characteristic parameter. Advantageously, the internal temperature characteristic parameter can be determined with a particularly low sensor technology overhead. Advantageously, characteristic parameters of the battery cell system that have already been detected during operation of the battery cell system can be used at least partially to determine the internal temperature characteristic parameter.

[0016] Furthermore, it is proposed that the output parameter comprises at least one (particularly the aforementioned) characteristic performance parameter of the cell system. In particular, the output characteristic parameter corresponds to a characteristic performance parameter of the cell system. Preferably, the operating characteristic parameter is at least partially detected on the cell system. Preferably, at least one characteristic performance parameter of the cell system (particularly the output voltage) is detected on the cell system (preferably by sensor). Preferably, the cell system comprises a detection unit for at least partially detecting the operating characteristic parameter. The detection unit is preferably connected to the control unit via data technology, in particular for wireless and / or wired data transmission. It is also conceivable that the control unit at least partially comprises the detection unit. It is conceivable that the operating characteristic parameter formed as an input characteristic parameter of the cell system and / or the operating characteristic parameter formed as an output characteristic parameter of the cell system are detected at least partially (preferably by sensor), preferably by means of the detection unit. The detection unit, for example, comprises at least one sensor unit for at least partially detecting the operating characteristic parameter. The detection unit is preferably configured (particularly by sensor) to detect at least the output characteristic parameter formed as a characteristic performance parameter. The sensor unit, for example, comprises at least one voltage sensor, in particular for detecting the characteristic performance parameter of the cell system formed as the output voltage. It is conceivable that the detection unit is configured to detect at least an input characteristic parameter of the cell system which is constituted as an operating parameter of the cell system. Additionally or alternatively, it is conceivable that at least one input characteristic parameter (preferably constituted as an input characteristic parameter of a control variable or a controlled variable, in particular constituted as a target value of an input characteristic parameter of a controlled variable) is read directly by means of the control unit, preferably provided by the control unit. Advantageously, characteristic parameters of the cell system which can be detected particularly easily (in particular at least one performance characteristic parameter of the cell system) can be used to determine the internal temperature characteristic parameter. Advantageously, the internal temperature characteristic parameter can be determined with particularly low technical expenditure. Advantageously, characteristic parameters of the cell system which have already been detected during operation of the cell system can be used to determine the internal temperature characteristic parameter.

[0017] Furthermore, it is proposed that a physical model be inverted and optimized to determine an internal temperature characteristic parameter, in particular with respect to an aging characteristic parameter. Preferably, the physical model is inverted and optimized with respect to an aging characteristic parameter (in particular, one of the input variables of the physical model) to determine the aging characteristic parameter, and preferably the internal temperature characteristic parameter and preferably at least one further cell characteristic parameter are subsequently determined based on the physical model and, in particular, from the determined aging characteristic parameter. Preferably, a time series is formed from the operating characteristic parameters. Preferably, in one method step, in particular in a detection step, operating characteristic parameters, preferably at least one input characteristic parameter and at least one output characteristic parameter, are recorded over time. Preferably, the recorded operating characteristic parameters are stored as a time series on a control unit, in particular on a memory element of the control unit. Preferably, in one method step, in particular in a selection step, a time is selected from the time series of the operating characteristic parameters, preferably by the control unit, wherein the control unit is in particular configured to determine at least the aging characteristic parameter for the selected time. Preferably, the control unit is configured to select a time from the time series of the operating characteristic parameters such that the system state of the cell system associated with this time can be described by the physical model. For example, it is conceivable that the physical model can only be applied to stable conditions, in particular the input characteristic parameters of the cell system, so that correspondingly sufficiently stable operating characteristic parameters are used. It is also conceivable that the operating characteristic parameters are at least partially preprocessed, for example by filtering to remove oscillations, etc. It is conceivable that the operating characteristic parameters, in particular at least one input characteristic parameter and at least one output characteristic parameter, are at least partially combined. It is also conceivable that the operating characteristic parameters associated with the instant are preferably at least partially converted in a conversion step, in particular by a control unit, in order to adapt to the physical model. Preferably, the operating characteristic parameters associated with the instant are converted, in particular in the conversion step, as required, into input variables and / or output variables of the physical model. For example, it is conceivable that the cell system has a plurality of stacks, each of which has a plurality of electrochemical cells, wherein averaging is performed on the individual stacks, or the detected current of the cell system is converted into a current density. Preferably, in particular in the determination step, an aging characteristic parameter is determined at a (preferably previously selected) time instant based on the physical model, for which the physical model predicts, together with at least one input characteristic parameter at the (preferably previously selected) time instant, at least one (preferably detected) output characteristic parameter at the (preferably previously selected) time instant. In particular, in order to determine the aging characteristic parameter, an optimization method, such as Bayesian optimization, simulated annealing, gradient method, etc., is preferably applied in the determination step, in particular involving the output characteristic parameter of the cell system detected for the at least one input characteristic parameter at the (preferably previously selected) time instant and the output characteristic variable predicted by the physical model for the input characteristic parameter at the selected time instant.An internal temperature characteristic parameter is determined based on the determined aging characteristic parameter, preferably in a determination step. Furthermore, it is conceivable to determine at least one further cell characteristic parameter of the cell system based on the determined aging characteristic parameter, preferably in a determination step. Preferably, the internal temperature characteristic parameter (in particular one of the output variables of the physical model) is determined based on a physical model based on the aging characteristic parameter determined based on the physical model (in particular by inverting and optimizing the physical model with respect to the aging characteristic parameter or by a regression model that can be generated with the aid of the physical model). Advantageously, the internal temperature characteristic parameter can be determined sensorlessly from the operating characteristic parameters of the cell system. Advantageously, the internal temperature characteristic parameter can be determined with particularly low sensor technology expenditure.

[0018] It is further proposed that the physical model be used to train a regression model, in particular the regression model already mentioned. The regression model is preferably trained based on results determined using the physical model. Preferably, the trained regression model is configured to replace the physical model at least for determining an aging characteristic parameter based on operating parameters of the battery cell system. The regression model is particularly configured to determine the aging characteristic parameter in an optimization method or to determine the aging characteristic parameter directly based on the operating parameters. In particular, it is conceivable that the regression model be trained to determine the aging characteristic parameter of the battery cell system directly from operating parameters detected during operation of the battery cell system (preferably at least one input characteristic parameter and at least one output characteristic parameter), wherein in particular, an inversion of the physical model is omitted. It is conceivable that the regression model be trained using operating parameters detected on the battery cell system and / or using a statistical experimental design (e.g., Latin hypercube sampling, active learning, etc.). In particular, the statistical experimental design is generated from a combination of operating parameters of the physical model for which the aging characteristic parameter is determined based on the physical model, with the results used to train the regression model. The training of the regression model is based on, for example, linear regression, random forests, Gaussian processes, neural networks, interpretable boosting machines, etc. Preferably, during operation of the cell system, at least the aging characteristic parameter is determined based on the trained regression model. Advantageously, the internal temperature characteristic parameter can be determined particularly time-efficiently and computationally efficiently based on the aging characteristic parameter determined by the regression model.

[0019] Furthermore, it is proposed to determine an internal temperature characteristic parameter in a spatially resolved manner. Preferably, a local distribution of the internal temperature characteristic parameter is determined. In particular, the spatially resolved internal temperature characteristic parameter corresponds to the local distribution of the internal temperature characteristic parameter. Furthermore, it is conceivable to determine at least one further cell characteristic parameter (in particular, at least one further internal characteristic parameter) of the cell system in a spatially resolved manner. The local distribution of the internal temperature characteristic parameter is in particular the local distribution of the internal temperature characteristic parameter within the cell system, preferably within at least one electrochemical cell or within a stack of a plurality of electrochemical cells. In particular, at least one operating parameter of the temperature control unit is adjusted based on the spatially resolved internal temperature characteristic parameter. Preferably, the spatially resolved internal temperature characteristic parameter is determined based on the operating characteristic parameters of the cell system based on a physical model, preferably by an optimization method that applies an inverse to the physical model for aging characteristic parameters or by a regression model using physical model parameters. In particular, the internal temperature characteristic parameter can be determined at a location or a list of locations in the cell system. It is also conceivable to determine a combination of multiple further cell characteristic parameters (preferably multiple internal characteristic parameters of the cell system) of the cell system at the location or the list of locations in the cell system, such as a product, a sum, a nonlinear function, etc. Furthermore, it is also conceivable to determine derived values ​​of the internal temperature characteristic parameter or derived values ​​of a combination of multiple further cell characteristic parameters, such as maximum, minimum, average values ​​in a partial volume or the total volume of the cell system, for describing a distribution, such as a first-order area moment, a second-order area moment, a support point of the cumulative distribution density, a gradient, or a rate of change. Advantageously, knowledge of the local distribution of the internal temperature characteristic parameter allows the efficiency and dynamics of the cell system to be improved, for example, by optimizing the operating strategy of the cell system. Advantageously, a particularly smooth, precise, and efficient operation of the cell system can be achieved.

[0020] Furthermore, it is proposed to predict an expected behavior of an internal temperature characteristic parameter based on a physical model. Alternatively or additionally, it is conceivable to predict an expected behavior of at least one further cell characteristic parameter (in particular at least one further internal characteristic parameter) and / or an aging characteristic parameter of the cell system based on the physical model. Based on the operating characteristic parameters of the cell system, an aging characteristic parameter is determined at a further time, in particular at a plurality of further time points, preferably from a time series of the operating characteristic parameters, based on the physical model, preferably similarly to the determination of the aging characteristic parameter at a previously selected time point, for example by inverting and optimizing the physical model or using a regression model. The corresponding internal temperature characteristic parameter is preferably determined based on the determined aging characteristic parameter at a further time point (in particular at a plurality of further time points) and the associated operating characteristic parameters based on the physical model. Preferably, another regression model (in particular a temperature course model) or a regression model is trained based on the internal temperature characteristic parameters determined at different time points and the corresponding operating characteristic parameters, preferably to describe the behavior of the internal temperature characteristic parameter based on the operating characteristic parameters and / or preferably to predict an expected behavior of the internal temperature characteristic parameter. In particular, the expected course of the internal temperature characteristic parameter is predicted by the further regression model (in particular a temperature course model). It is also conceivable to determine the time profile of at least one internal temperature characteristic parameter of the cell system, in particular based on the internal temperature characteristic parameters determined at different times and the corresponding operating characteristic parameters. Additionally or alternatively, it is also conceivable to determine the time profile of at least one other cell characteristic parameter and / or aging characteristic parameter. Advantageously, damage to the cell system caused by operation of the cell system within a critical temperature range can be particularly effectively prevented. Advantageously, the cell system can be operated particularly smoothly.

[0021] Furthermore, it is proposed that at least one operating parameter of the temperature control unit be adjusted based on an expected behavior of an internal temperature characteristic parameter. Preferably, the at least one operating parameter of the temperature control unit is adjusted based on the expected behavior of the internal temperature characteristic parameter and / or based on an internal temperature characteristic parameter that is preferably determined for the current operating characteristic parameter, in particular based on an inversion and optimization physical model with respect to an aging characteristic parameter or based on a regression model. It is conceivable that sensor signals from the detection unit are at least partially taken into account when adjusting at least one operating parameter of the temperature control unit (in particular by means of the control unit). The temperature control unit preferably has a feedforward control component. The feedforward control component is preferably based on an energy balance, wherein the storage term is the sum of the energy input minus the sum of the energy output. The storage term is in particular the product of the heat capacity and the time variation of the internal temperature characteristic parameter. The storage term can be formulated discretely (in particular spatially resolved) or globally for the entire cell system (in particular for the entire at least one electrochemical cell or the entire stack of a plurality of electrochemical cells), wherein the time variation of the internal temperature characteristic parameter is preferably provided based on a physical model, in particular at least at the feedforward control component. The control unit preferably includes the feedforward control component. The control unit or the temperature control unit preferably has at least one PID controller. The PID controller is preferably configured to empirically correct model errors of the feedforward control component. The PID controller preferably has access to internal temperature characteristic parameters, particularly those determined based on a physical model, preferably to maximum values ​​of the internal temperature characteristic parameters of the battery cell system. Advantageously, this can effectively prevent damage to the battery cell system due to operation within a critical temperature range. Advantageously, the battery cell system can be operated particularly smoothly.

[0022] Furthermore, a cell system, in particular the cell system already mentioned, is proposed, comprising at least one electrochemical cell, in particular the electrochemical cell already mentioned, and at least one control unit for carrying out the method according to the invention. Advantageously, a particularly robust cell system can be provided. Advantageously, a particularly dynamically operable cell system can be provided.

[0023] Furthermore, a computer program is proposed, comprising instructions which, when a computer executes the computer program, cause the computer to carry out the method according to the invention. The computer program is preferably stored on a storage element of the control unit. Alternatively, it is also conceivable to store the computer program on a portable data carrier, such as a USB stick, a portable hard drive, an optical data carrier (in particular a CD etc.), a cloud, a server etc. In particular, the control unit has a computer for executing the computer program. Advantageously, the method for operating a battery cell system can be adapted particularly conveniently and flexibly. Advantageously, the method can be applied to different battery cell systems and, in particular, can be adapted particularly conveniently to the corresponding battery cell system.

[0024] The method according to the invention, the battery cell system according to the invention, and / or the computer program according to the invention are not limited to the above-described applications and embodiments. In particular, the method according to the invention, the battery cell system according to the invention, and / or the computer program according to the invention may have a number of individual elements, components, units, and method steps that differs from the number described herein in order to achieve the method of action described herein. Furthermore, within the value ranges specified in this disclosure, values ​​within the stated limits are also to be considered disclosed and may be used arbitrarily. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Further advantages can be derived from the following description of the drawings. The drawings illustrate an embodiment of the present invention. The drawings, the description, and the claims contain numerous combined features. Those skilled in the art may consider these features individually as appropriate and combine them into other meaningful combinations.

[0026] Figure 1 A schematic diagram of a cell system according to the present invention is shown, which has at least one electrochemical cell and at least one control unit for executing a method for operating the cell system;

[0027] Figure 2 The schematic flow of the method according to the present invention is shown. DETAILED DESCRIPTION

[0028] Figure 1 A cell system 22 is shown having a plurality of electrochemical cells 24 (in Figure 1 Only one electrochemical cell 24 is shown by way of example). Alternatively, it is also conceivable that the cell system 22 has only one electrochemical cell 24. The electrochemical cells 24 are combined into a stack. It is also conceivable that the cell system 22 comprises a plurality of stacks formed by a plurality of electrochemical cells 24, which are preferably combined into a module or a tower. The electrochemical cells 24 are connected in series. The electrochemical cells 24 are configured as solid oxide fuel cells. Alternatively, it is also conceivable that the electrochemical cells 24 are configured as other fuel cells, for example as polymer electrolyte fuel cells, etc., electrolyte cells or storage cells. For example, it is also conceivable as an alternative to use the electrochemical cells 24 in an electrolyzer.

[0029] The cell system 22 has at least one control unit 26. The control unit 26 is configured to execute a method for operating the cell system 22. The control unit 26 is configured to adjust at least one operating parameter of the temperature control unit 30 as a function of at least one internal temperature characteristic parameter of the cell system 22. The temperature characteristic parameter is the temperature of the cell system 22, preferably the temperature of the stack formed by a plurality of electrochemical cells 24. The internal temperature characteristic parameter is a cell characteristic parameter of the cell system 22, preferably an internal characteristic parameter of the cell system 22.

[0030] The control unit 26 has at least one processor (not shown here) and a storage element (not shown here) and an operating program stored on the storage element. The storage element is designed as a digital storage medium, for example, a hard disk or the like.

[0031] The cell system 22 comprises a housing (not shown here), in which a stack of a plurality of electrochemical cells 24 is arranged. It is conceivable that the control unit 26 is at least partially arranged on the housing, in particular at least partially arranged in the housing. Alternatively or additionally, it is also conceivable that the cell system 22 has an external unit (not shown here), wherein the external unit in particular comprises at least part of the control unit 26. The external unit can be, for example, a cloud, a server, etc. It is conceivable that the external unit comprises a storage element of the control unit 26.

[0032] A computer program 28 is stored on the storage element and includes instructions that, when executed by a computer, cause the computer to carry out the method for operating the cell system 22. The control unit 26 includes a computer. Alternatively, it is also conceivable that the computer program 28 is stored on a portable data carrier, such as a USB stick, a portable hard drive, an optical data carrier (in particular a CD or the like), a cloud, a server, or the like.

[0033] The temperature control unit 30 has at least one fan unit (not shown here). The temperature control unit 30, in particular the fan unit, is configured to generate an air volume flow, preferably on the cathode side (not shown here) of the cell system 22. The fan unit, in particular the air volume flow that can be generated by the fan unit, is used to provide the oxygen ions required for the electrochemical reaction of the cell system 22. The cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, is temperature-controlled by means of the temperature control unit 30. The cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, is cooled in particular by means of the temperature control unit 30. The fan unit is configured to generate an air volume flow for cooling the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24. It is conceivable that the fan unit has one or more fans. Alternatively or additionally, it is also conceivable that the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, is heated by means of the temperature control unit 30, in particular at least by means of the fan unit. In particular, it is additionally or alternatively conceivable that the fan unit is provided to generate a (preferably preheated) air volume flow for heating the cell system 22 , in particular a stack formed from a plurality of electrochemical cells 24 .

[0034] Alternatively or in addition, it is also conceivable that the temperature control unit 30 has a heating unit for heating the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24. The heating unit can be designed as an electric heating unit, for example. The heating unit in particular has at least one heating element, preferably an electric heating element. Alternatively, however, it is also conceivable that the heating unit is designed as a fluid-based heating unit, in particular a liquid-based heating unit and / or a gas-based heating unit. The fluid-based heating unit is in particular provided for heating the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, by means of a fluid. The liquid-based heating unit is in particular provided for heating the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, by means of a liquid (e.g. water, etc.). The gas-based heating unit is provided for heating the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, by means of a gas. Furthermore, it is also conceivable as an alternative that the heating unit is designed as a combination of a fluid-based (in particular gas-based) heating unit and / or a liquid-based heating unit and an electric heating unit.

[0035] Alternatively or in addition, it is also conceivable that the temperature control unit 30 has a fluid cooling unit, in particular a liquid cooling unit and / or a gas cooling unit, for cooling the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24. The fluid cooling unit is particularly configured to cool the cell system 22 by means of a fluid. The liquid cooling unit is particularly configured to cool the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, by means of a liquid (e.g. water, etc.). It is conceivable that the liquid cooling unit is at least partially integrated with the liquid-based heating unit. It is also conceivable that the gas cooling unit is at least partially integrated with the gas-based heating unit. The gas cooling unit is particularly configured to cool the cell system 22, in particular a stack formed by a plurality of electrochemical cells 24, by means of a gas.

[0036] At least one operating parameter of the temperature control unit 30 includes at least one volume flow of the fan unit. Alternatively or additionally, it is conceivable that at least one operating parameter of the temperature control unit 30 includes the heating power of the heating unit (in particular an electric heating unit), the volume flow of a fluid-based heating unit (in particular a volume flow of a liquid-based heating unit and / or a volume flow of a gas-based heating unit), the volume flow of a fluid cooling unit (preferably a volume flow of a liquid cooling unit and / or a volume flow of a gas cooling unit), or other operating parameters of the temperature control unit 30 that are meaningful to a person skilled in the art.

[0037] Figure 2A schematic flow chart of a method for operating a cell system 22 is shown. In one method step of the method, in particular in the detection step 10, an operating characteristic parameter of the cell system 22 is detected at least partially on the cell system 22. The operating characteristic parameter comprises a plurality of input characteristic parameters of the cell system 22, or alternatively comprises only one input characteristic parameter of the cell system 22. The input characteristic parameters of the cell system 22 are operating parameters of the cell system 22, here exemplarily being the queried load current, temperature (in particular gas temperature), volume flow, gas composition, pressure, pressure difference, etc. It is conceivable that the operating parameters of the cell system 22 are at least partially control variables or controlled variables of the cell system 22, in particular actual values ​​or target values ​​of the controlled variables.

[0038] The characteristic operating parameter comprises at least one characteristic output parameter of the cell system 22. It is also conceivable that the characteristic operating parameter comprises a plurality of characteristic output parameters of the cell system 22. The characteristic output parameter of the cell system 22 comprises a characteristic performance parameter of the cell system 22. The characteristic performance parameter of the cell system 22 is the output voltage of the cell system 22, in particular the output voltage of a stack formed by a plurality of electrochemical cells 24.

[0039] The battery system 22 has a detection unit (not shown here) for at least partially detecting the operating characteristic parameters of the battery system 22. The detection unit is connected to the control unit 26 by data technology, in particular for wireless and / or wired data transmission. It is also conceivable that the control unit 26 at least partially includes the detection unit. The detection unit includes a sensor unit for at least partially detecting the operating characteristic parameters. The detection unit, in particular the sensor unit, is configured to at least detect an output characteristic parameter of the battery system 22 that is constituted as a performance characteristic parameter, in particular by means of a sensor. The sensor unit, for example, includes at least one voltage sensor, in particular for detecting a performance characteristic parameter of the battery system 22 that is constituted as an output voltage.

[0040] It is conceivable that the operating characteristic parameter formed as an input characteristic parameter of the cell system 22 can be detected at least partially by means of a detection unit (preferably in the form of a sensor). Alternatively or additionally, it is also conceivable that the input characteristic parameter (preferably formed as an input characteristic parameter of a control variable or a controlled variable, in particular as a target value of the input characteristic parameter of the controlled variable) is read at least partially directly by means of the control unit 26 in the detection step 10, preferably provided by the control unit 26.

[0041] In the detection step 10, operating characteristic parameters (particularly input characteristic parameters and output characteristic parameters) of the cell system 22 are recorded over time. A time series is formed based on the recorded operating characteristic parameters. The recorded operating characteristic parameters are stored as a time series on the control unit 26, particularly on a storage element of the cell system 22.

[0042] In one method step of the method, in particular in the selection step 12, a time is selected from the time series of the characteristic operating parameters, preferably by the control unit 26. The control unit 26 is configured to determine at least one aging characteristic parameter of the cell system 22 for the selected time. The control unit 26 is configured to select the time from the time series of the characteristic operating parameters such that the system state of the cell system 22 associated with this time can be described by a physical model of the cell system 22. For example, it is conceivable that the physical model can only be applied to stable conditions (in particular the input characteristic parameters of the cell system 22), so that correspondingly sufficiently stable characteristic operating parameters are used.

[0043] The physical model is a simulation model of the cell system 22, which in particular describes the operation of the cell system 22 in a steady state. The physical model is based on the finite element method and has clear reversibility, at least with respect to aging characteristic parameters.

[0044] It is conceivable that the physical model has clear reversibility with respect to the aging characteristic parameter, at least by filtering out physically irrelevant results of the physical model. For example, the physical model according to the publication by Zaccaria, Tucker, and Traverso, entitled "A distributed real-time model of degradation in a solid oxide fuel cell" (2016, "Journal of Power Sources", 311, 175-181), describes the degradation of a cell system 22, wherein the ohmic component of the internal voltage loss is provided with an aging characteristic parameter as a pre-factor.

[0045] Alternatively, it is also conceivable, for example, that other resistances other than the ohmic component of the internal voltage loss of the cell system 30 (in particular concentration losses or polarization losses) or the total internal resistance of the cell system 22 are multiplied by an aging characteristic parameter as a pre-factor. In a preferred physical model, the total specific surface resistance of the cell system 22 is multiplied by the aging characteristic parameter. The aging characteristic parameter describes the aging state of the cell system 30. In the unaged state of the cell system 22, the aging characteristic parameter has a value of 1, while for the aged state of the cell system 22, the aging characteristic parameter has a value greater than 1. The aging characteristic parameter is a scalar.

[0046] The physical model has multiple input variables and multiple output variables. Alternatively, it is also conceivable that the physical model has only one input variable and / or only one output variable. The input variables of the physical model are at least partially operating characteristic parameters of the battery cell system 22. The input variables of the physical model include aging characteristic parameters of the battery cell system 22. The input variables of the physical model include operating parameters of the battery cell system 22. The output variables of the physical model include at least one operating characteristic parameter of the operating characteristic parameters of the battery cell system 22, in particular, output characteristic parameters of the battery cell system 22 that are configured as performance characteristic parameters of the battery cell system 22. The output variables of the physical model include at least an internal temperature characteristic parameter. It is conceivable that the output variables of the physical model include at least one additional characteristic parameter of the battery cell system 22, preferably at least one additional internal characteristic parameter of the battery cell system 22. The at least one additional internal characteristic parameter of the battery cell system 22 can be, for example, a fluid distribution in the battery cell system 22 (preferably an oxygen distribution or a hydrogen distribution), a current density distribution in the battery cell system 22, or the like.

[0047] The physical model is in particular a mapping that maps the input variables of the physical model (preferably the operating parameters of the battery cell system 22 and the aging characteristic parameters of the battery cell system 22) to the output variables of the physical model, preferably to the performance characteristic parameters of the battery cell system 22, the internal temperature characteristic parameters of the battery cell system 22 and preferably at least one other internal characteristic parameter of the battery cell system 22.

[0048] It is conceivable that the characteristic operating parameters associated with the instant in question are at least partially converted to match the physical model in a method step (particularly in the conversion step 14), preferably by the control unit 26. The characteristic operating parameters associated with the instant in question are, if necessary, converted into input variables and / or output variables of the physical model, particularly in the conversion step 14. It is also conceivable that the characteristic operating parameters are at least partially preprocessed, for example, by filtering to remove oscillations, etc. Furthermore, it is conceivable that the characteristic operating parameters are at least partially combined, particularly in the conversion step 14.

[0049] In one method step of the method, in particular in determination step 16, an aging characteristic parameter at a selected time is determined based on the physical model, for which the physical model, together with the input characteristic parameters at the selected time, predicts a detected output characteristic parameter, in particular a performance characteristic parameter at the selected time. To determine the aging characteristic parameter, in determination step 16, the physical model is inverted and optimized, in particular with respect to the aging characteristic parameter.

[0050] In determination step 16, an optimization method is applied to determine the aging characteristic parameters, such as Bayesian optimization, simulated annealing algorithm, gradient method, etc., especially involving the output characteristic parameters of the battery cell system detected for the input characteristic parameters at the selected moment and the output characteristic parameters predicted by the physical model for the input characteristic parameters at the selected moment.

[0051] Based on the physical model of the cell system 22, an internal temperature characteristic parameter and at least one additional cell characteristic parameter are determined from the operating characteristic parameters of the cell system 22. The internal temperature characteristic parameter and the at least one additional cell characteristic parameter are determined based on the physical model of the cell system 22. The physical model is inverted and optimized with respect to an aging characteristic parameter (which is particularly one of the input variables of the physical model) to determine the aging characteristic parameter, and then the internal temperature characteristic parameter and preferably at least one additional cell characteristic parameter are determined based on the determined aging characteristic parameter based on the physical model.

[0052] An internal temperature characteristic parameter is determined based on the determined aging characteristic parameter, preferably in a determination step 16. Furthermore, it is conceivable to determine at least one further cell characteristic parameter of the cell system 22 based on the determined aging characteristic parameter, preferably in a determination step 16. Based on a physical model The internal temperature characteristic parameter (which is in particular one of the output variables of the physical model) is determined based on the aging characteristic parameter determined based on the physical model, in particular by inversion and optimization of the physical model with respect to the aging characteristic parameter or by a regression model producible with the aid of the physical model.

[0053] It is also conceivable that a physical model be used to train a regression model, in particular the regression model already mentioned. The regression model is trained based on the results determined using the physical model. The trained regression model is configured to replace the physical model, at least for determining the aging characteristic parameter based on the operating characteristic parameters of the cell system 22. The regression model is particularly configured to determine the aging characteristic parameter in an optimization method or directly based on the operating characteristic parameters. It is conceivable that the regression model be trained so that it determines the aging characteristic parameter directly from the operating characteristic parameters (preferably at least one input characteristic parameter and at least one output characteristic parameter) detected during operation of the cell system 22, in particular eliminating the need for inversion of the physical model. The regression model is trained using the operating characteristic parameters detected on the cell system 22 and / or using a statistical experimental design (e.g., using Latin hypercube sampling, active learning, etc.). In particular, the statistical experimental design is generated by combining the operating characteristic parameters of the physical model for which the aging characteristic parameter is determined based on the physical model, with the results used to train the regression model. The regression model is trained based on, for example, linear regression, random forests, Gaussian processes, neural networks, interpretable boosting machines, etc. During operation of the cell system 22 , the aging characteristic parameter is determined based on the trained regression model.

[0054] In particular, in determination step 16, an internal temperature characteristic parameter is determined spatially resolved. Additionally, it is conceivable to determine at least one further cell characteristic parameter, in particular at least one further internal characteristic parameter of the cell system 22, in spatially resolved manner. In determination step 16, a local distribution of the internal temperature characteristic parameter is determined. In particular, the spatially resolved internal temperature characteristic parameter corresponds to the local distribution of the internal temperature characteristic parameter. The local distribution of the internal temperature characteristic parameter is the local distribution of the internal temperature characteristic parameter within the cell system 22 (in particular, within a stack formed by a plurality of electrochemical cells 24). The local distribution of the internal temperature characteristic parameter is determined based on a physical model from the operating characteristic parameters of the cell system 22, preferably by an optimization method applied to an inverse physical model or by a regression model generated with the aid of the physical model. The internal temperature characteristic parameter can be determined at a location in the cell system 22 or at a location in a list. It is also conceivable to determine a combination of multiple cell characteristic parameters of the cell system (preferably multiple internal characteristic parameters of the cell system 22), such as a product, a sum, a nonlinear function, etc., at the location in the cell system 22 or at the location in the list. In addition, it is also conceivable to determine the derived value of the internal temperature characteristic parameter or the derived value of a combination of multiple battery cell characteristic parameters, such as the maximum value, minimum value, average value in a partial volume or the total volume of the battery cell system 22, for describing the distribution, such as the first-order area moment, the second-order area moment, the support point of the cumulative distribution density, etc., the gradient or the rate of change.

[0055] In one method step, in particular in the evaluation step 18, an expected behavior of the internal temperature characteristic parameter is predicted based on the physical model. Alternatively or additionally, it is also conceivable to predict the expected behavior of at least one further cell characteristic parameter (in particular at least one further internal characteristic parameter) and / or an aging characteristic parameter of the cell system 22 based on the physical model. Based on the operating characteristic parameters of the cell system 22, an aging characteristic parameter is determined at a further time (in particular at a plurality of further times) preferably from the time series of the operating characteristic parameters based on the physical model, preferably similarly to the determination of the aging characteristic parameter at a previously selected time, for example by inversion and optimization of the physical model or by means of a regression model. The corresponding internal temperature characteristic parameter is determined based on the physical model as a function of the determined aging characteristic parameter at a further time (in particular at a plurality of further times) and the associated operating characteristic parameters.

[0056] In evaluation step 18, a further regression model (in particular a temperature course model) or the regression model is trained based on the determined internal temperature characteristic parameters at different times and the corresponding operating characteristic parameters, in particular to describe the behavior of the internal temperature characteristic parameters as a function of the operating characteristic parameters and / or to predict an expected behavior of the internal temperature characteristic parameters. The expected course of the internal temperature characteristic parameters can be predicted using the further regression model (in particular the temperature course model) or the regression model.

[0057] It is also conceivable to determine the time profile of at least an internal temperature characteristic parameter of the cell system 22, in particular based on the determined internal temperature characteristic parameters and the corresponding operating characteristic parameters at different times. Additionally or alternatively, it is also conceivable to determine the time profile of at least one further cell characteristic parameter and / or aging characteristic parameter.

[0058] In the adjustment step 20, at least one operating parameter of the temperature control unit 30 is adjusted based on the internal temperature characteristic parameter. In the adjustment step 20, the at least one operating parameter of the temperature control unit 30 is adjusted, in particular by means of the control unit 26, based on at least the internal temperature characteristic parameter of the battery cell system 22 (in particular, based on an expected behavior of the internal temperature characteristic parameter and / or based on an internal temperature characteristic parameter preferably determined for the current operating characteristic parameter, in particular based on an inversion and optimization of a physical model or based on a regression model). The at least one operating parameter of the temperature control unit 30 is adjusted based on at least the local distribution of the internal temperature characteristic parameter.

[0059] It is conceivable that the sensor signal of the detection unit is at least partially taken into account when adjusting at least one operating parameter of the temperature control unit 30 in the adjustment step 20, in particular by means of the control unit 26. The temperature control unit 30 has a feedforward component (not shown here). The feedforward component is based on an energy balance, in which the storage item is the sum of the energy input minus the sum of the energy output. The storage item corresponds, in particular, to the product of the heat capacity and the time variation of the internal temperature characteristic parameter. The storage item can be formulated discretely (in particular, spatially resolved) or as a whole for the entire cell system 22 (in particular, the entire stack formed by a plurality of electrochemical cells 24), wherein the time variation of the internal temperature characteristic parameter is provided based on a physical model, in particular, at least at the feedforward component. The control unit 26 includes the feedforward component. The control unit 26 (in particular, the temperature control unit 30) has at least one PID controller. The PID controller is configured to perform an empirical correction of the model errors of the feedforward component. The PID controller can access the internal temperature characteristic parameter, in particular, determined based on the physical model, in particular, the maximum value of the internal temperature characteristic parameter of the cell system 22.

Claims

1. A method for operating a cell system (22) having at least one electrochemical cell (24), characterized in that: At least one operating parameter of a temperature regulating unit (30) of the battery cell system (22) is adjusted according to at least one internal temperature characteristic parameter of the battery cell system (22).

2. The method according to claim 1, characterized in that The internal temperature characteristic parameter is determined based on a physical model of the battery cell system (22).

3. The method according to claim 2, characterized in that The internal temperature characteristic parameter is determined according to the operating characteristic parameter of the battery cell system (22) based on the physical model of the battery cell system (22).

4. The method according to claim 3, characterized in that The operating characteristic parameter includes at least one input characteristic parameter of the battery cell system (22).

5. The method according to claim 4, characterized in that The input characteristic parameter includes at least one operating parameter of the battery system (22).

6. The method according to claim 3, characterized in that The operating characteristic parameter includes at least one output characteristic parameter of the battery system (22).

7. The method according to claim 6, characterized in that The output parameter includes at least one performance characteristic parameter of the battery cell system (22).

8. The method according to any one of the preceding claims, characterized in that The physical model is inverted and optimized to determine the internal temperature characteristic parameters.

9. The method according to any one of the preceding claims, characterized in that The physical model is used to train a regression model.

10. The method according to any one of the preceding claims, characterized in that The internal temperature characteristic parameter is determined in a spatially resolved manner.

11. The method according to any one of the preceding claims, characterized in that An expected behavior of the internal temperature characteristic parameter is predicted based on the physical model.

12. The method according to claim 11, characterized in that At least one operating parameter of the temperature regulating unit (30) is adjusted according to the expected behavior of the internal temperature characteristic parameter.

13. A cell system (22) having at least one electrochemical cell (24) and at least one control unit (26) for carrying out the method according to any one of the preceding claims.

14. A computer program (28) comprising instructions which, when a computer executes the computer program (28), cause the computer to perform the method according to any one of claims 1 to 12.

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