Method for operating an electrochemical device, and electrochemical device operated by means of such a method

Abstract

The invention relates to a method for operating an electrochemical device (10), and to an electrochemical device (10) operated by means of such a method, comprising an electrochemical unit (12). It is proposed to increase a temperature gradient (ΔT) prevailing at the electrochemical unit (12), preferably at the cathode, in particular within a predefined, preferably specified, temperature range.

Description

[0001] R. 414646

[0002] -1 -

[0003] Description

[0004] title

[0005] Method for operating an electrochemical as well as electrochemical which is operated using such a procedure

[0006] The present invention relates to a method for operating an electrochemical device, as well as an electrochemical device comprising an electrochemical unit.

[0007] State of the art

[0008] Methods for operating electrochemical devices comprising an electrochemical unit are known.

[0009] Disclosure of the invention

[0010] In contrast, the present method for operating an electrochemical device with the features of the main claim has the advantage that a temperature gradient prevailing at the electrochemical unit, particularly within a predetermined, preferably specified, temperature range, is increased. This allows the efficiency of the electrochemical device to be increased.

[0011] Advantageous further developments of the method according to the main claim are possible due to the features listed in the dependent claims. For example, it is advantageous if the temperature gradient within the specified temperature range is increased dynamically, in particular continuously or at regular intervals. This allows the efficiency of the electrochemical device to be flexibly increased. R. 414646

[0012] -2-

[0013] It is also advantageous to increase the temperature gradient within the specified temperature range depending on the lifespan of the electrochemical unit. This allows the efficiency of the electrochemical device to be maintained at a high level.

[0014] It is also advantageous if the temperature gradient within the specified temperature range is adjusted depending on a state parameter, particularly a component, of the electrochemical unit. This allows the efficiency of the electrochemical device to be maintained at a particularly high level.

[0015] It is advantageous if the temperature gradient within a given, and in particular specified, temperature range is increased at least towards a given, and in particular specified, minimum temperature value. This enables a very beneficial increase in efficiency.

[0016] It is particularly advantageous if the temperature gradient within the specified temperature range, preferably at least towards the specified minimum temperature value, is adjusted as a function of a degradation parameter of a reformer component of the electrochemical unit. This enables a particularly advantageous increase in efficiency.

[0017] It is also particularly advantageous if the temperature gradient is increased by adjusting, and in particular lowering, the actual temperature of a medium supplied to the electrochemical unit, preferably on the cathode side, at least substantially to a target temperature for the medium supplied to the electrochemical unit, preferably on the cathode side. This also enables a particularly advantageous increase in efficiency.

[0018] It is also advantageous if the temperature gradient within a given, and in particular specified, temperature range is increased at least up to a given, and in particular specified, maximum temperature value. This also enables a very beneficial increase in efficiency.

[0019] It is also particularly advantageous if the temperature gradient within the specified temperature range, preferably at least towards the specified, in particular specified, maximum temperature value, is dependent on a degradation parameter R. 414646

[0020] -3- is adapted to a functional layer component of the electrochemical unit. This also enables a particularly advantageous increase in efficiency.

[0021] A method according to one of the preceding claims, characterized in that the temperature gradient is increased by adjusting, and in particular increasing, the actual temperature of a medium discharged from the electrochemical unit, preferably on the cathode side, at least substantially to a target temperature for the medium discharged from the electrochemical unit, preferably on the cathode side. This also enables a particularly advantageous increase in efficiency.

[0022] The present electrochemical device has the advantage that it is operated using a method as described above. This allows the efficiency of the electrochemical device to be increased.

[0023] Within the scope of the present invention, an "electrochemical device" can be understood to mean, in particular, a device designed to convert chemical energy into electrical and / or thermal energy, or vice versa. An electrochemical device can, for example, be a fuel cell device, which in particular enables the conversion of a fuel, e.g., hydrogen, into electrical and / or thermal energy, or an electrolysis cell device, which in particular enables the conversion of electrical energy into chemical energy, preferably for storage. Preferably, the electrochemical device comprises one or more electrochemical units.

[0024] Within the scope of the present invention, an "electrochemical unit" can be understood to mean, in particular, a unit comprising a plurality of electrochemical cells. If the electrochemical cells are fuel cells, the electrochemical unit can, in particular, be a fuel cell unit. If the electrochemical cells are electrolysis cells, the electrochemical unit can be an electrolysis cell unit. Preferably, the electrochemical unit can be an electrochemical cell stack in which the plurality of electrochemical cells are stacked on top of one another. If the electrochemical cells are fuel cells, the electrochemical cell stack can, in particular, be a fuel cell stack. If the electrochemical cells are R. 414646

[0025] -4-

[0026] Electrolysis cells, the electrochemical cell stack can in particular be an electrolysis cell stack (English: Electrolyser Cell Stack).

[0027] Within the scope of the present invention, an "electrochemical cell" can be understood to mean, in particular, a cell designed to convert chemical energy into electrical energy or vice versa. An electrochemical cell can, for example, be a fuel cell, which in particular enables the conversion of a fuel, e.g., hydrogen, into electrical and / or thermal energy, or an electrolysis cell, which in particular enables the conversion of electrical energy into chemical energy, preferably for storage. In the case of a fuel cell, it can, for example, be designed as a solid oxide fuel cell (SOFC), a proton exchange membrane fuel cell (PEMFC), or an anion exchange membrane fuel cell (AEMFC).In the case of an electrolysis cell, it can be designed, for example, as a solid oxide electrolyzer cell (SOEC), a proton exchange membrane electrolyzer cell (PEMEC), or an anion exchange membrane electrolyzer cell (AEMEC).

[0028] Within the scope of the present invention, an “actual temperature” can be understood in particular as an actually prevailing temperature, which can be determined, for example, by means of a measurement, preferably direct, in particular by means of a sensor.

[0029] Within the scope of the present invention, a “target temperature” can be understood in particular as a temperature value which can be determined, for example, by a mathematical and / or experimental analysis, preferably an indirect one.

[0030] In the context of the present invention, the phrase "at least substantially" can be understood to mean, in particular, that a condition or property to which the phrase refers is present or fulfilled in its fundamental or important aspects or characteristics, but possibly not in all details or with perfect accuracy. In particular, the phrase indicates that, although there may be some minor tolerances, deviations, variations, or imperfections, the condition or property is nevertheless present. In particular, the phrase indicates that a close approximation to the condition or property R. 414646

[0031] -5- has been achieved, even if this or that is not 100% perfect or exact. In particular, the wording indicates that the condition or property can be achieved at least 90%, preferably at least 95%.

[0032] Drawings

[0033] The single figure shows a schematic representation of an exemplary embodiment of an electrochemical device.

[0034] Description of the exemplary implementations

[0035] The single figure shows a schematic representation of an embodiment of an electrochemical device 10. The electrochemical device 10 comprises an electrochemical unit 12. The electrochemical unit 12 comprises an electrochemical cell stack 14, which in turn comprises a plurality of electrochemical cells.

[0036] In the illustrated embodiment, the electrochemical device 10 is a fuel cell device 16 and the electrochemical unit 12 is a fuel cell unit 18. Accordingly, the fuel cell device 16 comprises the fuel cell unit 18.

[0037] In the case shown, the fuel cell unit 18 is an electrochemical unit 12, comprising a fuel cell stack 20, which in turn comprises a plurality of fuel cells.

[0038] In the case shown, the fuel cells are solid oxide fuel cells (SOFCs). Alternatively, they could also be proton exchange membrane fuel cells (PEMFCs) or anion exchange membrane fuel cells (AEMFCs).

[0039] In an alternative embodiment, it would also be possible for the electrochemical device 10 to be an electrolysis cell device and the electrochemical unit 12 to be an electrolysis cell unit. Accordingly, R. 414646 would then

[0040] -6- The electrolysis cell device comprises the electrolysis cell unit. Alternatively, in the case of an electrolysis cell device, it would also be possible for the electrolysis cell unit to comprise an electrolysis cell stack, which in turn comprises a multitude of electrolysis cells, for example, proton exchange membrane electrolyzer cells (PEMEC) or anion exchange membrane electrolyzer cells (AEMEC).

[0041] In the illustrated embodiment, a first medium M1 is supplied to a first electrode compartment 22 of the electrochemical unit 12 via a first media supply 24, and a second medium M2 is supplied to a second electrode compartment 26 via a second media supply 28. In the electrochemical unit 12, the first medium M1 is then electrochemically reacted with the participation of the second medium M2.

[0042] In the illustrated case of the fuel cell unit 18 as electrochemical unit 12, the first electrode compartment 22 is an anode compartment 30 and the second electrode compartment 22 is a cathode compartment 32. Furthermore, in the illustrated case of the fuel cell unit 18 as electrochemical unit 12, the first medium supplied, M1, is fuel containing a reducing agent, in this case hydrogen, and the second medium supplied, M2, is air containing an oxidizing agent, in this case oxygen. Thus, in the case of the fuel cell unit 18 as electrochemical unit 12, the fuel is supplied to the anode side, i.e., the anode compartment 30, while air is supplied to the cathode side, i.e., the cathode compartment 32. The hydrogen contained in the fuel is then electrochemically reacted with the oxygen contained in the air.

[0043] Subsequently, in the illustrated embodiment, a third medium M3 is removed from the first electrode compartment 22, in this case the anode compartment 30, via a first media outlet 34, and a fourth medium M4 is removed from the first electrode compartment 22, in this case the cathode compartment 32, via a second media outlet 36 from the electrochemical unit 12.

[0044] In the case of the fuel cell unit 18 as electrochemical unit 12, the third medium M3 is an exhaust gas discharged from the anode compartment 30, in this case an anode exhaust gas, which contains at least some of a product formed during the electrochemical reaction in the anode compartment 30. In contrast, in the case of the fuel cell unit 18 as electrochemical unit 12, the medium M4 is R. 414646

[0045] -7- an exhaust gas discharged from the cathode chamber 32, in this case a cathode exhaust gas, which contains at least partially an unused portion of air or oxygen.

[0046] In the illustrated embodiment, the first media discharge 34 leads via a first heat exchanger 38, which is in thermal exchange with the first media supply 24, and via a second heat exchanger 40, which is in thermal exchange with the second media supply 28. Thus, during operation of the electrochemical device 10, thermal energy generated during the electrochemical reaction of the fuel contained in the first medium M1 can be transferred to preheat the media M1 and M2 yet to be supplied.

[0047] In the illustrated embodiment, a first compressor 42 regulates the quantity of the first medium M1, in this case fuel, supplied to the electrochemical unit 12 (anode side in this case). A second compressor 44, in turn, regulates the quantity of the second medium M2, in this case air, supplied to the electrochemical unit 12 (cathode side in this case).

[0048] The thermal energy generated during the electrochemical reaction in electrochemical unit 12 is at least partially transferred to the media flowing through electrochemical unit 12. Thus, the media discharged from electrochemical unit 12, in this case the third medium M3 and the fourth medium M4, exhibit a higher level of thermal energy than the media supplied to electrochemical unit 12, in this case the first medium M1 and the second medium M2.

[0049] Accordingly, when the electrochemical device 10 is operated, a temperature gradient AT prevails at the electrochemical unit 12.

[0050] The temperature gradient AT, on the cathode side in the case shown, corresponds to a difference between the actual temperature (Tstack,out,Act) of the medium discharged from the electrochemical unit 12, in this case the fourth medium M4, and the actual temperature (Tstack,in,Act) of the medium supplied to the electrochemical unit 12, in this case the cathode side, in this case the second medium M2. Accordingly, the temperature gradient AT, in the case shown on the cathode side, can be set by adjusting the actual temperature (Tstack,in,Act) of the medium supplied to the electrochemical unit 12, in this case on the cathode side (second medium M2), and / or the actual temperature (Tstack,out,Act) of the medium discharged from the electrochemical unit 12, in this case on the cathode side (fourth medium M4). R. 414646

[0051] -8- In the illustrated embodiment, the electrochemical device 10 comprises a bypass 46, which is designed to divert a portion of the medium M2 supplied to the electrochemical device 10 from the second media supply 28 upstream of the second heat exchanger 40 and return it to the second media supply 28 downstream of the second heat exchanger 40. In the illustrated case, the quantity of the portion of the second medium M2 diverted by the bypass 46 can be controlled by a three-way valve 48, which is controllable in this case. This ensures that the portion of the second medium M2 diverted by the bypass 46 does not flow through the second heat exchanger 40 and is therefore not preheated.

[0052] By mixing the unheated portion of the second medium M2, diverted through bypass 48 in the case shown, downstream of the second heat exchanger 40, with the preheated portion of the second medium M2, which passes through the second heat exchanger 40 in the case shown, the actual temperature (Tstack,in,Act) of the medium supplied to the electrochemical unit 12, in this case on the cathode side, can be influenced. Similarly, in the case shown, the actual temperature (Tstack,in,Act) of the medium supplied to the electrochemical unit 12, in this case on the cathode side, can be regulated or set by controlling the amount of the portion of the second medium M2 diverted through bypass 46.

[0053] The actual temperature (Tstack,out,Act) of the medium discharged from the electrochemical unit 12 (in this case, the fourth medium M4) can be influenced by the total quantity of medium supplied to the electrochemical unit 12 (in this case, the second medium M2) via the cathode side. Similarly, in this case, the actual temperature (Tstack,out,Act) of the medium discharged from the electrochemical unit 12 (in this case, the fourth medium M4) via the compressor 44 can be regulated or set.

[0054] In the illustrated embodiment, the electrochemical device 10 is operated such that the prevailing temperature gradient AT does not leave a predetermined temperature range, specified in the illustrated case, thereby preventing damage to and / or in the electrochemical unit 12. R. 414646

[0055] -9-

[0056] The temperature range corresponds to a range between a predetermined, specified minimum temperature value Tceii.in and a predetermined, specified maximum temperature value Tceii.out.

[0057] Accordingly, in the illustrated embodiment, the actual temperature Tstack.in.Act of the medium supplied to the electrochemical unit 12, in this case the cathode side, here the second medium M2, and the actual temperature Tstack,out,Act of the medium discharged from the electrochemical unit 12, in this case the cathode side, here the fourth medium M4, are set such that the specified minimum temperature value Tceii.in is not undercut and the specified maximum temperature value Tceii.out is not exceeded.

[0058] Furthermore, the electrochemical device 10 shown is operated in such a way that the temperature gradient AT prevailing at the electrochemical unit 12, in this case on the cathode side, is increased, particularly within the specified temperature range. By increasing the temperature gradient AT, the volume flow rate of the medium supplied to the electrochemical unit 12, in this case on the cathode side, namely the second medium M2, can be kept essentially constant or only slightly increased. This, in turn, allows the power consumption of the first compressor 44 to be kept essentially constant or only slightly increased. Ultimately, this increases the overall efficiency of the electrochemical device 10.

[0059] In the illustrated embodiment, the temperature gradient AT can be dynamically increased within the specified temperature range. This allows the volumetric flow rate of the medium supplied to the electrochemical unit 12 (in this case, the cathode side), in this instance the second medium M2, to be flexibly increased during operation of the electrochemical device 10. Consequently, the efficiency of the electrochemical device 10 can be flexibly increased during operation.

[0060] In the case shown, the dynamic increase of the temperature gradient AT can occur at regular time intervals. Alternatively, it would also be possible for the dynamic adjustment of the temperature gradient AT to occur continuously.

[0061] In the case shown, the temperature gradient AT can be increased within the specified temperature range depending on the lifetime of the electrochemical unit 12. Thus, the volume flow rate of the electrochemical unit 12, R. 414646

[0062] -10- preferably cathode-side, supplied medium, in the case shown second medium M2, and thus the power consumption of the blower is adjusted in such a way as to counteract power losses of the electrochemical unit, which can be associated with a longer service life. This in turn allows the efficiency of the electrochemical device 10 to be maintained at a high level.

[0063] In this case, the temperature gradient AT within the specified temperature range can be adjusted as a function of a state parameter, in particular a degradation parameter, preferably of a component, of the electrochemical unit. Thus, the volume flow rate of the medium supplied to the electrochemical unit 12 (in this case, the cathode side), in this instance the second medium M2, and consequently the power consumption of the first compressor 44, can be adjusted in such a way as to counteract power losses of the electrochemical unit 12 caused by a change of state, for example, by degradation of components, within the electrochemical unit 12 over its lifetime. This allows the efficiency of the electrochemical device 10 to be maintained at a particularly high level.

[0064] The increase of the temperature gradient AT, particularly within the specified temperature range, can be achieved, for example, by the methods described in more detail below.

[0065] In a first embodiment, the electrochemical device 10 shown can be operated such that the temperature gradient AT within the specified temperature range is increased at least to the specified minimum temperature value Tceii.in. This enables a very advantageous increase in the efficiency of the electrochemical device.

[0066] In this first embodiment, the temperature gradient (AT) within the specified temperature range, preferably at least towards the specified minimum temperature value Tceii.in, can be adjusted as a function of a degradation parameter of a reformer component of the electrochemical unit 12. Thus, the volume flow rate of the medium supplied to the electrochemical unit 12, in this case the cathode side, and in this case the second medium M2, and therefore the power consumption of the compressor 44, can be adjusted such that power losses of the electrochemical unit 12 caused by degradation of a reformer component within the electrochemical unit 12 over its lifetime R. 414646

[0067] -11 - can be specifically counteracted. This enables a particularly advantageous increase in efficiency.

[0068] In this first embodiment, the temperature gradient AT can be adjusted, or increased, by setting the actual temperature Tstack.in.Act of the medium supplied to the electrochemical unit 12 (in this case, the cathode side), specifically the second medium M2, at least substantially to a target temperature Tstack.in.set for the medium supplied to the electrochemical unit (in this case, the cathode side), specifically the second medium M2. This allows the temperature gradient AT to be precisely controlled towards the specified minimum temperature value Tceii.in. This also enables a particularly advantageous increase in efficiency.

[0069] In the illustrated embodiment of the electrochemical device 10, the actual temperature (Tstack.in.Act) of the medium supplied to the electrochemical unit 12, in this case on the cathode side, in this case the second medium M2, can be measured by means of a sensor 50, in this case arranged in the second medium supply 28.

[0070] In the aforementioned first embodiment, the target temperature Tstack.in.set for the medium supplied to the electrochemical unit 12, in this case the cathode side (second medium M2), can correspond to the sum of the specified minimum temperature value Tceii.in and a compensation value Toffsetjn, where the compensation value Toffset n can be determined. Thus, it is possible to determine the target temperature Tstack.in.set, and in particular the compensation value Toffset n, via mathematical and / or experimental analysis, which simplifies the adjustment or control of the actual temperature Tstack.in.Act to the target temperature Tstackjn.set. This, in turn, enables a simplified adjustment of the temperature gradient AT, in this case towards the specified minimum temperature value Tceii.in. Accordingly, this also facilitates a simplified increase in efficiency.

[0071] The target temperature Tstackjn.set for the medium supplied to the electrochemical unit 12, in the case shown on the cathode side, here medium M2, in particular the compensation value Toffsetjn, can be adjusted dynamically in the first embodiment, preferably continuously or at regular time intervals. Thus, it is possible to adjust the target temperature Tstackjn.set, in particular the compensation value Toffsetjn, via a R. 414646

[0072] -12- mathematical and / or experimental analysis can also be used to dynamically determine the actual temperature Tstack.in.Act, thereby simplifying the dynamic adjustment or control of the actual temperature Tstack.in.set to the target temperature Tstack.in.set. Accordingly, this can simplify and flexibly increase the efficiency of the electrochemical device 10 during its operation.

[0073] In the aforementioned first embodiment, the target temperature Tstack.in.set for the medium supplied to the electrochemical unit 12 (in this case, the cathode side), specifically the second medium M2, and in particular the compensation value Toffsetjn, can be adjusted as a function of a state parameter, especially a component, of the electrochemical unit 12. This allows for the consideration of changes in state, such as those caused by component degradation within the electrochemical unit 12 over its lifetime, when adjusting the target temperature Tstack.in.set for the medium supplied to the electrochemical unit 12 (in this case, the cathode side), specifically the compensation value Toffsetjn. Consequently, the efficiency of the electrochemical device 10 can be simplified and maintained at a high level.

[0074] The target temperature Tstack.in.set for the medium supplied to the electrochemical unit 12, in this case the cathode side, here the second medium M2, and in particular the compensation value Toffset n, can be adjusted in the first embodiment as a function of a degradation parameter of a reformer component of the electrochemical unit. This allows a specific change in state, caused specifically by degradation of the reformer component of the electrochemical unit 12 over its lifetime, to be taken into account when adjusting the target temperature Tstackjn.set for the medium supplied to the electrochemical unit 12, in this case the cathode side, here the second medium M2, and in particular the compensation value Toffsetjn. Accordingly, the efficiency of the electrochemical device 10 can be simplified and maintained at a particularly high level.

[0075] In the aforementioned first embodiment, the target temperature Tstackjn.set for the medium supplied to the electrochemical unit 12, in the case shown on the cathode side, here the second medium M2, in particular the compensation value Toffsetjn, can be determined from a comparison, in particular of the state parameter, preferably the degradation parameter, with an existing data set, in particular a characteristic curve, stored in a control unit 56. The existing data set, or the characteristic curve, can be derived from an experimental, preferably one-time, R. 414646

[0076] -13-

[0077] The temperature may have been determined through analysis, for example a measurement, and / or a mathematical analysis, for example a simulation. This makes it particularly easy to adjust or regulate the actual temperature Tstack.in.Act to the target temperature Tstack.in.set. This, in turn, greatly simplifies the efficiency of the electrochemical device 10 and allows it to be maintained at a high level.

[0078] In a second embodiment, the electrochemical device 10 shown can be operated such that the temperature gradient AT within the specified temperature range is increased at least to the specified maximum temperature value Tceii.out. This also enables a very advantageous increase in the efficiency of the electrochemical device 10.

[0079] In this second embodiment, the temperature gradient AT can be adjusted within the specified temperature range, preferably at least up to the specified maximum temperature value Tceii.out, as a function of a degradation parameter of a functional layer component of the electrochemical unit 12. Thus, the volume flow rate of the medium supplied to the electrochemical unit 12 (in this case, the second medium M2), and consequently the power consumption of the compressor 44, can be adjusted in such a way as to specifically counteract power losses in the electrochemical unit 12 caused by degradation of a functional layer within the electrochemical unit 12 over its lifetime. This also enables a particularly advantageous increase in the efficiency of the electrochemical device 10.

[0080] In the second embodiment mentioned, the temperature gradient AT can be increased by adjusting, and in particular increasing, the actual temperature Tstack,out,Act of the medium discharged from the electrochemical unit 12 (in this case, the cathode side), here the fourth medium M4, at least substantially to a target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in this case, the cathode side), here medium M4. Thus, the temperature gradient AT can be specifically controlled towards the predetermined maximum temperature value Tceii.out, as specified here. This also enables a particularly advantageous increase in the efficiency of the electrochemical device 10.

[0081] In the illustrated embodiment of the electrochemical device 10, the

[0082] Actual temperature Tstack,out,Act of the electrochemical unit 12, in the case shown R. 414646

[0083] -14- cathode-side, discharged medium, in this case fourth medium M4, are measured by means of a sensor 52, in this case arranged in the second media discharge 36.

[0084] The target temperature Tstack,out,set for the medium discharged from electrochemical unit 12 (in this case, the cathode side), here the fourth medium M4, can, in the second embodiment mentioned, correspond to a difference between the specified maximum temperature value Tceii.out and a compensation value Toffset,out, which can be determined. Thus, it is possible to determine the target temperature Tstack,out,set, and in particular the compensation value Toffset,out, via mathematical and / or experimental analysis, which simplifies the adjustment or control of the actual temperature Tstack,out,Act to the target temperature Tstack,out,set. This, in turn, enables a simplified adjustment of the temperature gradient AT, in this case towards the specified maximum temperature value Tceii.out. Accordingly, this also facilitates a simplified increase in efficiency.

[0085] In the second embodiment mentioned, the target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in this case, the cathode side), in this instance the fourth medium M4, and in particular the compensation value Toffset,out, can be dynamically adjusted, preferably continuously or at regular intervals. This makes it possible to dynamically determine the target temperature Tstack,out,set, and especially the compensation value Toffset,out, via mathematical and / or experimental analysis, thereby simplifying the dynamic adjustment or control of the actual temperature Tstack,out,Act to the target temperature Tstack,out,set. Consequently, the efficiency of the electrochemical device can be simplified and flexibly increased during operation.

[0086] The target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in the case shown, on the cathode side), here the fourth medium M4, and in particular the compensation value Toffset,out, can be adjusted in the aforementioned second embodiment depending on a state parameter, in particular a component, of the electrochemical unit 12. Thus, a change in state, which, for example, is caused by degradation of components within the electrochemical unit 12 over its lifetime, can be taken into account when adjusting the target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in the case shown, on the cathode side), here the fourth medium M4, and in particular the compensation value Toffset,out. R. 414646

[0087] -15- will be. Accordingly, the efficiency of the electrochemical device 10 can be simplified and efficiently maintained at a high level.

[0088] In the second embodiment mentioned, the target temperature Tstack,out,set for the medium discharged by the electrochemical unit 12 (in this case, the cathode side), here the fourth medium M4, and in particular the compensation value Toffset,out, can be adjusted as a function of a degradation parameter of a functional layer component of the electrochemical unit 12 and / or a reformer component of the electrochemical unit 12. This allows a specific change in state, caused specifically by degradation of the functional layer component and / or the reformer component of the electrochemical unit 12 over its lifetime, to be taken into account when adjusting the target temperature Tstack,out,set for the medium discharged by the electrochemical unit 12 (in this case, the cathode side), here the fourth medium M4, and in particular the compensation value Toffset,out.Accordingly, this can simplify the efficiency of the electrochemical device 10 and keep it at a particularly high level of efficiency.

[0089] The target temperature Tstack,out,set for the medium discharged by the electrochemical unit 12, in this case the cathode side, here the fourth medium M4, in particular the compensation value Toffset,out, can be determined in the aforementioned second embodiment by comparing, in particular the state parameter, preferably the degradation parameter, with an existing data set, in particular a characteristic curve, stored in the control unit 56. The existing data set, or the characteristic curve, can be determined from an experimental analysis, preferably a single measurement, and / or a mathematical analysis, for example a simulation. This allows for a particularly simplified adjustment or control of the actual temperature Tstack,out,Act to the target temperature Tstack,out,set.This in turn makes it possible to simplify the efficiency of the electrochemical device 10 and to maintain it efficiently at a high level.

[0090] In a third embodiment, the electrochemical device 10 shown can be operated such that the actual temperature Tstack,out,Act of a medium discharged by the electrochemical unit 12 is adjusted at least substantially to a target temperature value Tstack,out,set for the medium discharged by the electrochemical unit 12, wherein the actual temperature T S The actual temperature Tstack, anode, out, Act of a medium discharged from the anode side of electrochemical unit 12, in this case a third medium M3, is determined by measuring the actual temperature Tstack, anode, out, Act of the medium M3. This is determined by measuring the actual temperature Tstack, anode, out, Act of the medium M3 discharged from the anode side of electrochemical unit 12.

[0091] -16- By reducing the influence of temperature losses, such as those that can occur when measuring the actual temperature Tstack, cathode, out, Act of the medium discharged from the cathode side of the electrochemical unit 12, the influence of temperature losses, such as those that can occur when measuring the actual temperature Tstack, cathode, out, Act of the medium discharged from the electrochemical unit 12, can be reduced. This, in turn, enables more precise control of the actual temperature Tstack, out, Act of the medium discharged from the electrochemical unit 12 and thus also a more targeted increase of the temperature gradient AT. Accordingly, the efficiency of the electrochemical device 10 can be specifically increased.

[0092] In the illustrated embodiment of the electrochemical device 10, the actual temperature Tstack, Anode, out, Act of the medium discharged from the electrochemical unit 12, in the case shown on the anode side, in this case the third medium M3, can be measured by means of a sensor 54, in this case arranged in the first medium discharge 34.

[0093] In this third embodiment, the target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in this case, the anode side), here the third medium M3, can correspond to a difference between a predetermined, specified maximum temperature value Tceii.out and a compensation value Tottset,out, whereby the compensation value Tottset,out can be determined, in particular, set. This makes it possible to determine the target temperature Tstack,out,set via a mathematical and / or experimental analysis, thereby simplifying the adjustment or control of the actual temperature Tstack,out,Act to the target temperature Tstack,out,set. Thus, in addition to more precise control of the actual temperature Tstack,out,Act, simpler control of the actual temperature Tstack,out,Act is also enabled. Accordingly, this also facilitates a simplified increase in efficiency.

[0094] In the third embodiment mentioned, the target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12 (in this case, the anode side), specifically the third medium M3, and in particular the compensation value Tottset,out, cannot be dynamically adjusted. This simplifies the determination of the target temperature Tstack,out,set, which in turn further simplifies the efficiency improvement.

[0095] The target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12, preferably on the anode side, in this case the third medium M3, in particular the compensation value Tottset,out, can be determined once, in particular set, in the aforementioned third embodiment. R. 414646

[0096] -17-

[0097] Furthermore, the target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12, in this case the anode side, here the third medium M3, in particular the compensation value Toffset,out, in the aforementioned third embodiment, can be determined, preferably once, by measuring a temperature drop, in particular between a temperature substantially prevailing in the electrochemical unit 12 and a temperature prevailing at the anode-side outlet of the electrochemical unit 12, particularly on the anode and / or cathode side. This allows for a particularly reliable determination of the target temperature Tstack,out,set, in this case the compensation value Toffset,out. Accordingly, this also enables a particularly reliable increase in efficiency.

[0098] The target temperature Tstack,out,set for the medium discharged from the electrochemical unit 12, in this case the anode side, here the third medium M4, in particular the compensation value Toffset,out, can be determined in this third embodiment, preferably once, during operation of the electrochemical device 10 or before commissioning the electrochemical device 10. Thus, the determination of the target temperature value Tstack,out,set, in this case the compensation value Toffset,out, can be carried out, for example, during the start-up operation of the electrochemical device, during assembly of the electrochemical device, or during factory adjustment. This simplifies the operation of the electrochemical device.

[0099] In a further, alternative embodiment, the electrochemical device 10 shown can be operated with a combination of the first, second, and / or third embodiments described above. This would enable a particularly significant increase in the efficiency of the electrochemical device 10.

[0100] Within the framework of this further, alternative embodiment, it would also be possible for the electrochemical device 10 shown to be operated in such a way that the temperature gradient AT within the specified temperature range is increased, in particular dynamically, towards the specified minimum temperature value Tceii.in, as described above, and, in particular dynamically, towards the specified maximum temperature value Tceii.out, as described above, as described above. R. 414646

[0101] -18-

[0102] In this further, alternative embodiment, it would also be possible for the electrochemical device 10 shown to be operated in such a way that the temperature gradient AT within the specified temperature range, as described above, is increased, in particular dynamically, towards the specified minimum temperature value Tceii.in, and, as described above, the actual temperature Tstack,out,Act of a medium discharged by the electrochemical unit 12 is set at least substantially to a target temperature value Tstack,out,set for the medium discharged by the electrochemical unit 12, wherein the actual temperature T S tack,out,Act is determined by measuring the actual temperature Tstack, Anode, out, Act of a medium discharged from the anode side of the electrochemical unit 12, in this case a third medium M3.

[0103] Likewise, within the framework of this further, alternative embodiment, it would be possible for the electrochemical device 10 shown to be operated in such a way that the temperature gradient AT within the specified temperature range, as described above, is increased dynamically towards the specified minimum temperature value Tceii, and as described above, as described above, towards the specified maximum temperature value Tceii.The actual temperature Tstack, out, Act of a medium discharged by the electrochemical unit 12 is increased, in accordance with the third embodiment described above, and is set at least substantially to a target temperature value Tstack, out, set for the medium discharged by the electrochemical unit 12, wherein the actual temperature Tstack, out, Act is determined by measuring the actual temperature Tstack, anode, out, Act of a medium discharged on the anode side of the electrochemical unit 12, in this case the third medium M3.

Claims

R. 414646 -19- Claims 1. Method for operating an electrochemical device (10) comprising an electrochemical unit (12), characterized in that a temperature gradient (AT) prevailing at the electrochemical unit (12), preferably on the cathode side, is increased, in particular within a predetermined, preferably specified, temperature range.

2. Method according to claim 1, characterized in that the temperature gradient (AT) within the specified temperature range is increased dynamically, in particular continuously or at regular time intervals.

3. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within the specified temperature range is increased depending on the lifetime of the electrochemical unit (12).

4. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within the specified temperature range is adapted as a function of a state parameter, in particular a degradation parameter, preferably a component, of the electrochemical unit (12).

5. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within a predetermined, in particular specified, temperature range is increased at least towards a predetermined, in particular specified, minimum temperature value (Tceii.in).

6. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within the R. 414646 -20- specified temperature range, preferably at least towards the specified, in particular specified, minimum temperature value (Tceii.in), depending on a degradation parameter of a reformer component of the electrochemical unit (12).

7. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) is increased by adjusting, in particular lowering, an actual temperature (Tstack n.Act) of one of the electrochemical units (12), preferably on the cathode side, to at least substantially a setpoint temperature (Tstack n.set) for the medium (M2) supplied to the electrochemical unit, preferably on the cathode side.

8. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within a predetermined, in particular specified, temperature range is increased at least towards a predetermined, in particular specified, maximum temperature value (Tceii.out).

9. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) within the predetermined temperature range, preferably at least towards the predetermined, in particular specified, maximum temperature value (Tceii.out), is adjusted as a function of a degradation parameter of a functional layer component of the electrochemical unit (12).

10. Method according to one of the preceding claims, characterized in that the temperature gradient (AT) is increased by adjusting, in particular increasing, an actual temperature (Tstack,out,Act) of a medium (M4) discharged from the electrochemical unit (12), preferably on the cathode side, at least substantially to a target temperature (Tstack,out,set) for the medium (M4) discharged from the electrochemical unit (12), preferably on the cathode side.

11. Electrochemical device (10) operated by a method according to one of the preceding claims.

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