Operation of electrolysis system having plurality of electrolysis cells

Abstract

The invention relates to a support device (90) for an electrolysis device (10) having a plurality of electrolysis cells (12), having connection contacts (72) for electrically coupling to respective electrodes of the electrolysis cells (12). According to the invention, the support device (90) has at least one voltage detection unit for detecting a cell voltage of a respective one of the electrolytic cells (12), and an evaluation unit (18), which is signal-coupled to the at least one voltage detection unit, the invention relates to a support device for determining at least one cell characteristic or at least one aging state for a respective one of the electrolytic cells (12), comprising controllable electronic current source circuits (42), the number of which is equal to the number of electrolytic cells (12), a respective one of the current source circuits (42) is electrically coupled to an electrode of a respective one of the electrolytic cells (12), and a direct current is individually applied to the respective electrolytic cell (12), which direct current can be set in accordance with a current source control signal.

Description

Technical Field

[0001] The invention relates to a support device for an electrolysis system having a plurality of electrolysis cells, which has a connection contact for electrically coupling to the individual electrodes of the electrolysis cells. The invention also relates to an electrolysis system having a plurality of electrolysis cells. Finally, the invention also relates to a method for operating an electrolysis system having a plurality of electrolysis cells, wherein, for electrically coupling to the support device for the electrolysis system, the individual electrodes of the electrolysis cells are electrically coupled to the connection contacts of the support device. Background Art

[0002] Electrolysis devices, support devices for the electrolysis devices and methods for operating the electrolysis devices are known in the prior art, so that no special written evidence is required for this purpose. Electrolysis cells and electrolysis devices of this type, in particular electrolysis cells and electrolysis devices for electrolyzing water into hydrogen and oxygen, are known in the prior art, for example from DE 197 29 429 C1. The basic function of electrolysis, in particular water electrolysis, is known to those skilled in the art, so a detailed description is not given here.

[0003] Electrolysis plants with single, but in particular multiple, electrolysis cells, which are usually at least partially electrically connected in series, are used in particular for the production of substances that can preferably be used on an industrial scale, such as hydrogen during water electrolysis, carbon monoxide during carbon dioxide electrolysis, etc. For this purpose, a suitable small DC voltage is applied to at least two electrodes of the respective electrolysis cell during the prescribed operation, which DC voltage can be in the range of several volts or even possibly less than 1V. Corresponding to the amount of substance to be provided by electrolysis, a corresponding DC current is provided as electrolysis current by the electrolysis energy source. For electrolysis cells connected in series, this DC current flows through all battery cells connected in series. The series circuit is electrically coupled to the electrolysis energy source. However, in principle, the electrolysis cells can not only be connected in series, but can also be connected at least partially in parallel.

[0004] In particular, in water-based electrolysis, such as chlorine / alkali electrolysis, PEM electrolysis, etc., membranes are usually provided, which separate the corresponding reaction chambers of the corresponding reaction regions of the corresponding electrolysis cells, in which the corresponding electrodes are arranged. Usually, catalysts are arranged on such membranes in order to enable the electrolysis process or to accelerate the electrolysis process in a catalytic manner. The electrolysis is usually carried out in such a way that, in the specified operation, an electrolysis current or a suitable DC voltage, also referred to as cell voltage, is applied to the electrodes of the corresponding electrolysis cells.

[0005] It is at least partially critical for the respective electrolytic cells that in particular a transition is made from or to an operating state that is different from the prescribed operating state. This relates in particular to the start-up of the electrolytic cell or electrolysis device and the shut-down of the electrolytic cell or electrolysis device. In particular, when shutting down after the prescribed operation, residual substances, in particular dissolved or gaseous residual gases, may still be present in the electrolytic cell, which may in some cases cause the electrolytic cell to exhibit a fuel cell function. However, this can irreversibly damage the electrolytic cell, so that the fuel cell function must be avoided. For this purpose, it is known to apply a protective voltage, also called a polarization voltage, to the electrolytic cell outside the prescribed operation time, which is selected so that the fuel cell function can be avoided as much as possible. For an electrolytic cell for the electrolysis of water, the protective voltage can be, for example, about 1.25V. Once the electrolytic cell is cooled accordingly and the residual gas is removed, the provision of the protective voltage can be stopped.

[0006] Such a support device is used in particular to support or enable safe operation of an electrolytic cell, in particular an electrolytic device. For this purpose, the electrolytic cell is electrically connected to the support device so that the electrolytic cells can be supplied with polarization currents independently of one another. For example, EP 3 982 501 A1 discloses such a device.

[0007] It has also been shown that electrolytic cells may age in different ways and / or have different properties. This has proven to be problematic, in particular for electrolytic cells connected in series and when a protective voltage is provided as a polarization voltage by the voltage applied to the series circuit. Due to different aging or properties, it may happen that the voltage applied to the series circuit, in particular when the electrolytic cells are connected in series, is not evenly distributed to all electrolytic cells connected in series. Therefore, the voltage of the series connection needs to be selected to be very large so that the protective voltage can still be reliably reached for the most unfavorable electrolytic cell. However, this also results in the application of a correspondingly high voltage to other electrolytic cells, which may be significantly greater than the protective voltage, so that these electrolytic cells continue to operate in the electrolysis operation mode. Therefore, in order to avoid the presence of explosive mixtures in these electrolytic cells, nitrogen is usually used for purging.

[0008] It is also known from EP 3 982 501 A1 to apply a protective voltage to each electrolytic cell individually. However, providing the electrolytic cells with separate protective voltages has proven to be relatively labor-intensive. In addition, neither the aging state nor any properties of the electrolytic cell are taken into account in this solution, so that undesirable states may continue to occur. Summary of the invention

[0009] The object of the present invention is to enable improved operation of electrolysis cells and electrolysis plants and to provide corresponding methods.

[0010] For this type of support device, the present invention particularly proposes that the support device has at least one voltage detection unit for detecting the cell voltage of a corresponding electrolytic cell among the electrolytic cells; and an evaluation unit coupled to the at least one voltage detection unit in terms of signal technology, which is used to determine at least one electrolytic cell characteristic or at least one aging state for a corresponding electrolytic cell among the electrolytic cells, wherein controllable electronic current source circuits are provided, the number of which is the same as the number of electrolytic cells, wherein corresponding current source circuits among the current source circuits are electrically coupled to the electrodes of the corresponding electrolytic cells among the electrolytic cells, and a direct current is applied to the corresponding electrolytic cell individually, and the direct current can be set according to a current source control signal.

[0011] For an electrolysis plant of this type, the invention provides in particular that the electrolysis plant has a supporting device according to the invention.

[0012] For a method of this type, the present invention in particular proposes that the cell voltage of the electrolytic cell is detected by means of at least one voltage detection unit of a support device which is electrically coupled to the connecting contact, wherein the voltage detection unit provides a corresponding voltage signal as a function of the corresponding detected voltage, wherein the voltage signal is evaluated by means of an evaluation unit in order to determine at least one electrolytic cell characteristic or at least one aging state for the corresponding electrolytic cell.

[0013] The present invention is based in particular on the idea that the cell voltage of each electrolytic cell is detected, in particular when these electrolytic cells are connected in series, and is evaluated by means of an evaluation unit. The evaluation unit can then determine at least one electrolytic cell characteristic or at least one aging state based on these data. For this purpose, it can be considered, for example, what cell current is applied or previously applied to the respective electrolytic cell in the electrolytic cell. Of course, the cell characteristics and aging state of the respective electrolytic cell can also be determined. These data can be used, for example, to better operate the electrolytic cells individually by setting the cell current individually, so that these electrolytic cells can be operated individually as far as possible in the optimal operating state of each of these electrolytic cells. This can be particularly provided for the electrolysis operation, the start-up of the electrolytic device and / or the closing of the electrolytic device according to the regulations. In addition, it can be realized that, for example, data is provided for the electrolysis control unit located at a higher level of the electrolytic device, which allows the load capacity of the respective electrolytic cell to be identified. This load capacity (which can also include the aging state) can be used to achieve the power setting of the electrolytic cell within a predetermined operating range. This can be used, for example, to change, set, etc. the electrolysis power of the electrolytic device.

[0014] If, for example, a low electrolysis power is to be activated, it is advantageous to operate an electrolytic cell with an unfavorable aging state as far as possible, whereas, if a high electrolysis power is desired, an electrolytic cell with a low aging state is preferably activated, i.e., a substantially new electrolytic cell is preferably activated. Of course, it can also be provided that by operating the electrolytic cell as specified and activating or deactivating the electrolytic cell accordingly, different aging states of the electrolytic cell can be balanced. The following knowledge is used here, that the cell voltage can be set according to the aging state when a predetermined cell current is applied. When a predetermined cell current is applied, the cell voltage generally increases with increasing aging. Therefore, the aging state of the electrolytic cell can be determined, for example, according to the operating parameters of the electrolytic cell. The operating parameters can be, for example, the cell voltage, the cell current, the temperature of the electrolytic cell, for example the flow value of a fluid such as a liquid and / or a gas, etc.

[0015] Furthermore, it is conceivable that the cell voltage may also depend on the activation of the catalyst etc. used in the respective electrolysis cell. Thus, in conjunction with the support device, an improved operation of the electrolysis cells of the electrolysis device and thus also of the electrolysis device as a whole can be achieved.

[0016] At the same time, the support device according to the invention also enables a safer and more reliable startup and shutdown of the electrolysis plant as a whole. This can be achieved in particular by detecting the respective cell voltages of the electrolysis cells during operation as specified and / or during startup or shutdown and taking this into account when setting the respective cell currents. Preferably, the respective cell currents can also be taken into account. This is preferably achieved based on determined cell characteristics or determined aging states. The cell characteristics can, for example, include respective characteristic curves of the respective cells of the electrolysis cells, if necessary other cell parameters and / or the like.

[0017] The supporting device has a corresponding connection contact, which is used to connect to the electrolytic device, in particular to connect to the electrolytic cell in the form of electrical coupling, so that the desired electrical connection with the electrode of the electrolytic cell can be established. The supporting device also has a voltage detection unit for detecting the cell voltage of the electrolytic cell. For this purpose, the voltage detection unit is preferably electrically coupled to the connection contact of the supporting device. The voltage detection unit can detect the corresponding cell voltage, for example, individually or in a time-multiplexed manner. The voltage detection unit provides a corresponding voltage signal, which is transmitted to an evaluation unit coupled in terms of signal technology. Therefore, the corresponding voltage signal is available in the evaluation unit, so that the evaluation unit can at least determine the electrolytic cell characteristics of the corresponding electrolytic cell or at least determine the aging state. The supporting device, in particular the voltage detection unit and, if necessary, the evaluation unit can be an electronic hardware circuit. However, they can also be formed at least in part by a program-controlled computing unit. Of course, a combination thereof can also be provided.

[0018] The invention is particularly advantageous if the electrolytic cells of the electrolytic device are at least partially connected in series. However, the invention is not limited to this. The support device can also be used for electrolytic devices with electrolytic cells that are at least partially connected in parallel. Of course, a combination of a series circuit and a parallel circuit of electrolytic cells can also be provided.

[0019] According to an improved solution, the voltage detection unit has a plurality of voltage sensors, the number of which is the same as the number of electrolytic cells, wherein a corresponding voltage sensor among the voltage sensors is electrically coupled to an electrode of a corresponding electrolytic cell among the electrolytic cells, and is used to detect the cell voltage of the corresponding electrolytic cell and output a corresponding voltage signal according to the detected cell voltage. Therefore, the voltage detection unit can detect the cell voltages of a plurality of electrolytic cells at the same time and output a corresponding voltage signal. This allows very fast signal processing. In short, this allows the support device to be improved and the function to be improved if necessary.

[0020] It is further proposed that the supporting device has at least one current sensor for detecting the cell current of at least one of the electrolytic cells and outputting a current signal according to the detected cell current. If the electrolytic cells are connected in series, a single current sensor is usually sufficient. However, it can also be provided that a corresponding separate current sensor for detecting the cell current is preferably provided for each electrolytic cell. With the aid of this current sensor, the cell current can preferably be detected at least during the prescribed electrolysis operation or outside the prescribed electrolysis operation, i.e., for example, the polarization current is also detected when the electrolysis device is turned off. The current sensor is preferably also coupled to the evaluation unit in terms of signal technology, so that the current signal can be transmitted to the evaluation unit. The evaluation unit can also additionally consider at least one current signal during the evaluation.

[0021] It is also proposed that the support device has a controllable, electronic current source circuit, the number of which is the same as the number of multiple electrolytic cells, wherein a corresponding current source circuit in the current source circuit is electrically coupled to the electrodes of the corresponding electrolytic cell in the electrolytic cells, and a direct current is applied to the corresponding electrolytic cell, which can be set according to a current source control signal. It can be achieved that a corresponding direct current can be applied to each electrolytic cell in the multiple electrolytic cells separately. It has been proven to be particularly advantageous that the electrolytic device, more precisely the electrolytic cell, is operated outside the prescribed electrolysis operation in such a way that a protective current, i.e. a polarization current, is preferably applied to the electrolytic cell in order to, for example, suppress or avoid undesirable fuel cell functions. This is especially true when starting up the electrolytic device or shutting down the electrolytic device, otherwise, in particular, the electrolytic cells connected in series may be supplied unevenly. Using a separately arranged current source circuit, a cell current can be applied to each electrolytic cell in the electrolytic cell separately. This cell current can be, for example, a protective current for avoiding fuel cell functions. Preferably, the protective current depends on the determined electrolytic cell characteristics and / or the determined aging state.

[0022] Each of the current source circuits can be set by means of a current source control signal. The current source control signal can be provided to one or more current source circuits, for example, by an evaluation unit, but can also be provided by a higher-level electrolysis control of the electrolysis device. As a result, each of the electrolysis cells can be operated in the best possible respective operating state.

[0023] It is further proposed that the evaluation unit detects the cell voltage and the cell current during a predeterminable time period and determines the cell characteristics and / or aging state of the electrolytic cell accordingly. Preferably, the cell current can be detected at least during the specified electrolytic operation or at least outside the specified electrolytic operation. However, it is particularly advantageous to be able to detect the cell current substantially permanently. For this purpose, it can be provided that the evaluation unit can use the data of a new electrolytic cell as a reference value or starting value, or retrieve the data as a data item from an external data storage via a communication connection. With the help of the corresponding current source circuit, a separate characteristic curve can also be detected and stored in real time for each electrolytic cell. In this way, for example, the cell characteristics of an unknown electrolytic cell can also be determined. This data can be used to determine changes in the corresponding cell characteristics of the corresponding electrolytic cell in further operation, in particular changes in the aging state caused by operation. The cell characteristics include, but are not limited to, the operating state, changes in the operating state, operating parameters and / or changes in operating parameters that can be determined for the electrolytic cell. Of course, it can also be provided that data on the state of the end of the life of the electrolytic cell can be stored in a retrievable manner, wherein the evaluation unit can determine whether the corresponding electrolytic cell in the electrolytic cell has reached its end of life. If the end of life is reached, the evaluation unit can, for example, output a signal indicating that the respective electrolytic cell should be maintained or replaced. This can further improve the function of the electrolysis device as a whole. At the same time, the determined aging state of the electrolytic cell can be used to provide individual current source control signals based thereon, so that the electrolytic cell can preferably be supplied with a cell current depending on its respectively determined aging state. This also achieves a further improvement in the operation of the electrolysis device as a whole.

[0024] It has proven to be advantageous if the evaluation unit determines the cell properties and / or aging state of all electrolysis cells coupled to the support device and determines control data for the operating state during electrolysis operation, startup and / or shutdown of the electrolysis device based on the determined aging state. The control data may include, but are not limited to, data on the current source control signals, so that the best possible operation of the electrolysis cells can be achieved, in particular when starting up or shutting down the electrolysis device, in particular when the electrolysis cells are connected in series.

[0025] It is further proposed that the support device has a separately operable housing with a plug connector for electrically connecting the support device to the electrolytic cell. This makes it possible to easily connect the support device to the electrolytic cell, in particular to the electrolytic device, and to establish reliable electrical contact. The separately operable housing can be a closed housing, so that the support device is reliably protected from external influences. This is particularly advantageous if harmful substances, such as explosive gas mixtures, corrosive atmospheres and / or the like, may be present in the vicinity of the support device. The connecting contact can preferably also be arranged on the housing in an electrically contacting manner.

[0026] According to another design, the evaluation unit determines the operating state of all electrolytic cells coupled to the evaluation unit, and provides a state signal to the electrolysis control unit at a higher level according to the determined operating state, so as to control the cell current according to the state signal. The state signal can be used to set each current source control signal. However, it can also be used to control the cell current provided by the electrolysis control unit at a higher level during the specified electrolysis operation. Thus, the overload of each electrolytic cell, especially the electrolytic cell of severe aging, can be avoided in particular. Thus, for example, it can be achieved that the cell current can be controlled in a suitable manner during the protection operation at least during the specified electrolysis operation or at least outside the specified electrolysis operation. In addition, it can be avoided that the electrolytic cell is operated outside the allowed specified electrolysis operation, which can be determined by the electrolytic cell structure and / or design parameters, for example. In short, the reliability of the operation and the service life of the electrolytic device can be further improved or increased.

[0027] The support device preferably has a communication interface, through which the support device is connected to the electrolysis control unit of the electrolysis device at a higher level for communication. The communication interface can be used for wireless communication or wired communication.

[0028] The support device can also detect other operating parameters of the electrolytic cell, preferably for each electrolytic cell separately. For this purpose, the support device can have a suitable parameter sensor, which can be at least partially integrated in the support device or arranged in the corresponding electrolytic cell. Such a parameter sensor can be used, for example, to detect the temperature in the electrolytic cell or its electrolytic cell membrane or process fluid and process gas, detect the flow rate of the process fluid in the corresponding electrolytic cell, and in particular for the electrolytic cell for electrolysis of water, the parameter sensor is used for water vapor measurement, detection of gas composition, for example, in order to determine whether the gas composition contains a combustible mixture, for pressure measurement, etc. Preferably, these parameter sensors can also be coupled to the evaluation unit in terms of signal technology, so that the evaluation unit can supplement the evaluation based on these signals. Further improvement of the operation of the electrolytic device can also be achieved here.

[0029] In the method according to the invention for operating a plurality of electrolytic cells, a corresponding current source circuit of a plurality of current source circuits of a support device is advantageously electrically coupled to electrodes of a corresponding electrolytic cell of the plurality of electrolytic cells, wherein a direct current is applied individually to the corresponding electrolytic cell, which direct current can be set as a function of a current source control signal.

[0030] Thus, the support device can be used to independently perform the protection operation and normal operation of each of the plurality of electrolytic cells. At the same time, the determined aging state of the electrolytic cell can be used, for example, to provide a separate current source control signal based thereon, and the electrolytic cells are preferably individually supplied with a cell current according to their respectively determined aging state. Here, depending on the operating mode, the protection current is supplied to the respective electrolytic cell during the protection operation, or the operating current for normal electrolysis operation is supplied during the normal operation.

[0031] Of course, the advantages and effects given for the supporting device according to the invention also apply to the electrolysis device according to the invention and the method according to the invention, and vice versa. In this regard, device features can also be expressed as method features, and vice versa.

[0032] The embodiments explained below relate to preferred embodiments of the present invention. The features, feature combinations given above in the specification and the features and feature combinations mentioned below in the description of the embodiments and / or shown separately in the drawings can be used not only in the corresponding combinations given, but also in other combinations. Therefore, the present invention also includes the following embodiments or the following embodiments are also considered to be disclosed, which are not clearly shown and explained in the drawings, but can be derived and generated by the explained embodiments through separate feature combinations. The features, functions and / or effects shown according to the embodiments can independently represent the various features, functions and / or effects of the present invention to be considered independently of each other, which can also improve the present invention independently of each other. Therefore, the embodiments should also include other combinations in addition to the combinations in the explained embodiments. In addition, the described embodiments can also be supplemented by other features, functions and / or effects in the features, functions and / or effects already described in the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In the accompanying drawings, the same reference numerals represent the same features and functions.

[0034] Figure 1 An electrolysis device is shown in a schematic connection diagram, the electrolysis device having a plurality of electrolysis cells connected in series, the electrolysis cells being connected to an electrolysis energy source and an auxiliary energy source connected in parallel with the electrolysis energy source;

[0035] Figure 2 The schematic diagram shows the Figure 1A polarization characteristic curve of an electrolytic cell of an electrolytic device, wherein the cell voltage of the electrolytic cell related to the electrolytic current of the electrolytic cell is shown;

[0036] Figure 3 With Figure 1 A similar schematic connection diagram shows an electrolysis plant, in which a protection unit is connected in parallel to each individual electrolysis cell;

[0037] Figure 4 A schematic diagram is shown, wherein the corresponding graphs are used to illustrate the Figure 1 the clock current of the electrolytic cell as a protection current as well as the cell voltage and a control signal for the protection current,

[0038] Figure 5 A schematic curve diagram showing another waveform diagram of a protection current,

[0039] Figure 6 shows that is applied according to Figure 5 Schematic diagram of the aging of the protective current of the electrolytic cell determined based on the polarization characteristic curve,

[0040] Figure 7 Shown according to Figure 3 Schematic block connection diagram of the protection unit,

[0041] Figure 8 The structure of an electrolysis device with supporting equipment is shown in a schematic block diagram,

[0042] Fig. 9 a schematic perspective view of a first embodiment of an arrangement of a support device on an electrolysis device designed as a module, and

[0043] Fig.10 With Fig. 9 A similar schematic diagram shows a second embodiment of the arrangement of a support device on an electrolysis device designed as a module. DETAILED DESCRIPTION

[0044] Figure 1 A schematic connection diagram of an electrolysis device 52 is shown with a plurality of electrolysis cells 12 electrically connected in series. The electrolysis cells 12 are used in the present case to electrolyze water into hydrogen and oxygen in a reaction chamber (not shown in further detail) which is constructed between the corresponding electrodes of the respective electrolysis cell 12. Of course, in alternative embodiments, other substances can also be reactants for the electrolysis in order to convert them into corresponding other substances as products.

[0045] The series-connected electrolytic cells 12 are connected to a main rectifier 14 as an electrolysis energy source. The main rectifier 14 provides an operating voltage 50 which is applied to the series connection of the electrolytic cells 12 so that an electrolysis current 48 flows through the electrolytic cells 12 during normal operation, ie, electrolysis operation.

[0046] The series circuit consisting of the polarization rectifier 54 and the protective inductor 58 as an auxiliary energy source is connected to the series circuit of the electrolytic cells 12 in a manner connected in parallel with the main rectifier 14. The polarization rectifier 54 and the protective inductor 58 are used to apply a rectifier voltage 68 to the electrolytic cells 12 during the period outside the specified electrolysis operation, and the rectifier voltage is selected so that a protective current 56 is formed, which is large enough so that all electrolytic cells 12 are at least applied with a sufficiently large polarization voltage U0 ( Figure 2 ), the polarization voltage is set to be greater than or equal to the required protection voltage U S This is intended to avoid undesirable processes in the electrolysis cell 12 during periods other than those during the intended electrolysis operation.

[0047] Figure 2 A diagram 60 is shown in a schematic diagram, wherein the ordinate 62 represents the cell voltage at the respective cell connection 28 of each of the plurality of electrolytic cells 12. The abscissa 64 represents the respective cell current of the electrolytic cell 12. The graph 66 shows the dependence of the cell voltage on the cell current as a polarization characteristic curve. N Indicates that when the electrolytic current intensity I is applied to the electrolytic cell 12 during the specified electrolytic operation n At an electrolysis current of 48, an electrolysis voltage is formed at the electrolysis cell 12. The intersection of the graph line 66 with the ordinate 62 defines the polarization voltage U0, below which a change in the polarization of the cell current occurs.

[0048] In the present embodiment of the electrolysis cell 12 for electrolyzing water, the electrolysis voltage U N is about 1.8 to 1.9 V. In the current design, the polarization voltage U0 may be about 1.48 V. Depending on the structure of the electrolytic cell 12, the polarization voltage U0 may also be in the range of about 1.25 V to about 1.45 V. When the cell voltage is greater than about 1.48 V, hydrogen and oxygen are generated, and the electrolytic cell 12 begins the electrolysis function.

[0049] In this regard, according to Figure 1 The electrolysis system 52 of FIG. 5 is disadvantageous because gas is still produced outside the actual electrolysis process, that is, outside the intended electrolysis operation. In this case, undefined states can occur in the electrolysis system 52, which in the worst case can even lead to the production of ignitable gas mixtures. In order to ensure safety in this regard, additional extensive protective measures are required.

[0050] Furthermore, in particular when starting up the electrolysis device 52 or shutting down the electrolysis device 52, a protective voltage U S The distribution is not uniform, resulting in a situation where the polarization voltage U0 is undershot in one or more electrolysis cells 12. This problem occurs in particular because the electrolysis cells 12 are not all identical and / or have different aging states, that is, have different cell characteristics and / or different aging states. As a result, an undesired fuel cell operation may occur, which may damage the corresponding electrolysis cell 12.

[0051] Figure 3 Now an electrolysis device 10 is shown in which the above-mentioned problems can be reduced or even completely avoided. The electrolysis device 10 is based on Figure 1 Here, too, a series circuit consisting of a plurality of electrolytic cells 12 is provided, which is connected in parallel with a main rectifier 14 in order to supply electrical energy during the prescribed electrolysis operation. In this context, the electrolytic device 10 corresponds to the electrolytic device 52, so reference is made to the embodiments related thereto as a supplement. Figure 1 and Figure 2 The corresponding implementation method of .

[0052] According to Figure 1 The design scheme is different from that of Figure 3 The electrolysis device 10 of the present invention provides that the electrolysis device has a support device 90 with a protection device 16 and a control unit 18, wherein the protection device is used to provide a separate protection current 76 ( Figure 4 ). The protective device 16 is connected to the electrolytic cell 12, more precisely to its electrolytic cell connection 28. The protective device 16 has an auxiliary voltage source 22 as an electrical energy source for providing an auxiliary DC voltage 24. In addition, the protective device 16 has a contact connection 26 for electrical connection to the electrolytic cell connection 28 of the electrolytic cell 12 of the series circuit. Therefore, in the current design, it is provided that all electrolytic cell connections 28 are electrically coupled to the protective device 16.

[0053] The protective device 16 also has a corresponding protective unit 40, which has a connecting contact 72, which is electrically coupled to the corresponding electrolytic cell 12, more precisely to its electrodes, via a contact connection 26 and a cell connection 28. In addition, the protective unit 40 has two connecting connections 34, by means of which the protective unit can be electrically coupled to the auxiliary voltage source 22. As a result, a protective current 76 can be applied individually to each electrolytic cell 12, so that a cell voltage above the polarization voltage U0 can be reliably achieved, even independently of the specified operation.

[0054] The auxiliary voltage source 22 can be electrically coupled, for example, to a public energy supply network or the like. Each protection unit 40 provides a separate protection current 76 for the corresponding electrolytic cell 12, thereby enabling a separate protection voltage U S .

[0055] Protection voltage U S ( Figure 2 ) is selected so that no fuel cell effect occurs at any electrolysis cell 12, that is to say it is avoided that gas residues react according to the fuel cell principle in the respective electrolysis cell 12 to form water and thus release energy. This would lead to significant aging and damage to the respective electrolysis cell 12.

[0056] In the present case, a switching unit 36 ​​is also provided, which is connected to the connection contact 72 of the protection unit 40 of the support device 90 and the contact connection 26 of the electrolysis device 10, more precisely the electrolytic cell 12. The switching unit 36 ​​is not absolutely necessary for the present invention and can also be omitted or constructed in a modified manner as required. In the present design, the switching unit 36 ​​is constructed so that the protection unit 40 is electrically coupled to the contact connection 26 according to the switching state of the switching unit 36, so that a protection current 76 is provided to the connection contact 72. This provides the possibility that the protection unit 40 is electrically connected to the electrolytic cell 12 only when it is necessary or desired based on the operating conditions of the electrolysis device 10. Therefore, if the electrolytic cell 12 is operated in electrolysis operation as specified, the protection unit 40 can be deactivated relative to the electrolytic cell 12 by means of the switching unit 36. In addition, it can be provided, for example, that if it is desired to be able to detect the cell voltage independently of the switching state of the switching unit 36, the voltage sensor 44 (see Figure 7 ) is directly connected to the contact connection portion 26.

[0057] The switching unit 36 ​​has a separate switching element 38, which is formed in the present case by a reed relay or a reed contact, for each contact connection 26. Of course, in alternative embodiments, corresponding relays or contacts or also electronic switching elements can also be provided.

[0058] The respective switching states of the switching elements 38 are controlled together by the control unit 18 of the support device 90, so that all switching elements 38 assume substantially the same switching state in each case. For this purpose, the control unit 18 can include a control circuit which is also used, in particular, to control the protective device 16. In the present case, the control unit 18, as will be explained in detail below, provides an evaluation function, so that it also assumes the function of an evaluation unit.

[0059] In order to control the switching unit 36, in the present embodiment, it is provided that the cell current of the series circuit of the electrolytic cells 12 is detected by means of a current sensor (not shown in detail) as a sensor unit. The current sensor transmits a corresponding sensor signal to the control unit 18, which evaluates the signal. As soon as the sensor signal is less than a predetermined comparison value, the switching unit 36 ​​switches from the disconnected switching state to the connected switching state. This means that each electrolytic cell 12 is acted upon by the protective device 16, which is now activated.

[0060] Currently, the protection units 40 are identical. However, if desired, the protection units may also be different. Figure 7 The schematic block connection diagram of exemplarily explains one of the protection units 40. In order to provide the protection current 76, the protection unit 40 has an electronic converter 42 electrically coupled to the auxiliary voltage source 22, which is currently a DC / DC converter of the current source circuit type that can be controlled by current, is current-separated, and is current-sourced. At the same time, the converter 42 emits a predeterminable protection current 76 according to a current source control signal. The characteristics of the current source circuit are usually mainly, in particular, that the current source circuit outputs a current for a predetermined operating range, such as a voltage range, etc., by measuring, and its value basically depends only on the current source control signal. For this purpose, the converter 42 is connected to the control unit 18 of the support device 90 via the interface connection part 70. The control unit 18 mainly provides the corresponding current source control signal, so that the electrolytic cell 12 connected to the protection unit 40 can be provided with a separate protection current 76.

[0061] Furthermore, the protection unit 40 has a voltage sensor 44 connected to the connection contact 72, with which the cell voltage of the electrolytic cell 12 can be detected. A corresponding voltage signal is transmitted from the voltage sensor 44 via the interface connection 70 to the control unit 18. The control unit 18 evaluates the voltage signal and determines therefrom a protection current 76 to be set for the respective electrolytic cell 12. Depending on the respectively determined protection current 76, a current source signal is transmitted to the converter 42. Even though the protection current 76 can be a constant DC current, the provided protection current 76 does not need to be a constant DC current, as will be explained below.

[0062] Provision is made here that the protection units 40 of the protection device 16 are all identical and can be controlled by means of the control unit 18 .

[0063] Figure 4 A schematic curve diagram is used for Figure 3 One of the electrolytic cells 12 shown in FIG. 1 shows, by way of example, a protection current 76 of a protection unit 40 coupled to the corresponding electrolytic cell 12. Figure 4In the graph 80 shown, the left ordinate represents the voltage in V and the right ordinate represents the current in A. The abscissa represents the time axis in ms. The graph line 74 shows a converter control signal inside the converter 42, which controls the output of the protection current 76. At present, the converter control signal 74 is a rectangular signal, so that the converter 42 can provide a clocked direct current. The clocked direct current representing the protection current 76 is represented by means of the corresponding graph line 76. It can be seen that the protection current 76 is switched on or off synchronously with the converter control signal 76 according to the corresponding graph line 76.

[0064] During this operation, the voltage sensor 44 (see Figure 7 ) detects the cell voltage of the electrolytic cell 12. For this purpose, there is currently no need to set a separate circuit, as has been described with reference to Figure 7 As explained. It can be seen that due to the clock direct current as protection current 76, the cell voltage of the electrolytic cell 12 is a direct voltage 78 that fluctuates with a relatively low amplitude. At present, the voltage fluctuations are in the range from about 1.25V to about 1.35V. Due to the capacitive effect of the electrolytic cell 12, the voltage curve according to the graph 78 is generated. This also explains why according to the graph 76, the amplitude is not constant during the corresponding duration of the corresponding direct current pulse, but slightly decreases. This is also a reaction caused by the capacitive properties of the electrolytic cell 12.

[0065] The amplitude of the clock DC current and the duty cycle of the clock DC current can be set as required by the control signal of the control unit 18. For this purpose, the control unit 18 can control the voltage sensor 44 (see Figure 7 and Figure 8 ) is evaluated accordingly. In any case, the amplitude and duty cycle of the clock DC current are determined so that the detected cell voltage of the electrolytic cell 12 is greater than the corresponding associated protection voltage U S Furthermore, by taking into account the cell voltage of the electrolytic cell 12 and the cell current caused by the clocked DC current as protection current 76, the aging state of the electrolytic cell 12 can be determined based on the evaluation of the control unit 18. The duty cycle and / or the amplitude of the clocked DC current can then be set in addition to the aging state of the electrolytic cell 12 determined.

[0066] In an alternative embodiment, it can be provided that the regulation can be carried out by using the sensor signal of the voltage sensor 44. For this purpose, it can be provided that, in order to set the duty cycle of the clocked DC current, the cell voltage is compared with the separate protection voltage U of the electrolytic cell 12. S The battery voltage can then be compared with the separate protection voltage U SThe larger predetermined voltage comparison value is compared, and the current pulse of the clock DC current can be terminated according to the comparison. Therefore, by selecting the predetermined voltage comparison value, the duty cycle and / or frequency of the clock DC current can be set.

[0067] Furthermore, it can be provided that in an alternative embodiment a constant direct current is also superimposed on the clock direct current. This makes it possible, for example, for the protection current 76 not to reach a zero value. This can increase reliability and safety.

[0068] Figure 5 A waveform diagram 88 of another protection current 76 is shown in another schematic curve diagram. The protection current 76 is again shown in the corresponding graph 76. The abscissa is the time in ms and the ordinate is the current in A. It can be seen that in this embodiment, the clock direct current has current pulses in the range between 0.5 and 1.5 A. The current pulses are currently separated by corresponding time periods of approximately 145 ms.

[0069] Figure 6 In another schematic diagram, a curve diagram 86 is shown, which shows how the clock protection current 76 affects the aging of the electrolytic cell 12. The abscissa is the current in A, and the ordinate is the voltage in V. The curve 84 shows the effect of the clock protection current 76 on the aging of the electrolytic cell 12. Figure 5 The polarization curve of the electrolytic cell 12 at the protection current 76 is shown in Figure 82. Another polarization curve at the end of the investigation period is shown in Figure 82. 2 The electrolytic cell 12 with an electrode surface of 166 hours was performed, wherein the power was turned on during a period of 166 hours as the investigation period, and the protection current 76 was about 1.3 A at most. It can be seen from the graph 84 and the graph 82 that there is no significant difference in the polarization curve. It can be inferred from this that the electrolytic cell 12 has not undergone measurable aging.

[0070] The frequency of the clock direct current can be selected in the range of about 10 Hz to about 100 Hz. Preferably, the frequency is in the range of about 30 Hz.

[0071] Figure 8 The structure of the electrolysis device 10 with the support device 90 is shown in a schematic block diagram. Figure 8It can be seen that the electrolytic cells 12 in the present case are summarized as modules to realize the modular or modular structure of the electrolytic device 10. The fluid connection part 98 not shown in detail is connected at the module, and the reactant water to be electrolytically decomposed and the hydrogen and oxygen produced during the specified electrolysis can be supplied via the fluid connection part as the product. Each electrolytic cell 12 is electrically connected to the corresponding current source circuit 42 so that the cell current can be applied separately. In addition, each electrolytic cell 12 is electrically connected to the corresponding voltage sensor 44. The voltage sensor 44 and the current source circuit 42 are currently connected to the control unit 18 in terms of signal technology. The control unit 18 used as an evaluation unit determines the aging state of all electrolytic cells 12 coupled to the support device 90, and determines the control data for starting or shutting down the electrolytic device 10 according to the determined aging state. The control data is transmitted from the control unit 18 to the electrolysis control unit 32 located at a higher level via a communication connection not shown in detail. The electrolysis control unit 32 is used for the higher-level control of the electrolytic device 10. The electrolysis control unit 32 can be connected to a plurality of electrolysis devices 10 and can, for example, jointly control all electrolysis devices 10 that are communicatively connected thereto. In addition, it is currently provided that the control unit 18 is coupled in terms of communication technology to a further control unit 18 of a further support device 90, which is used to operate the further electrolysis device.

[0072] Fig. 9 A schematic three-dimensional view of a first design of an arrangement of a support device 90 at an electrolysis device 10 designed as a module with a module housing 96 is shown. It can be seen that the support device 90 has a housing 94 that can be operated separately, which has a substantially flat cuboid structure. The support device 90 also has a plug connector 92 for electrically connecting the support device 90 to the electrolysis cell 12, which is currently connected to the housing 94 via an electrical connection line 100. In this way, the connection of the support device 90 to the electrolysis device 10 can be easily achieved. The plug connector 92 is connected to the module at the end side and is arranged at the module housing 96 in this way.

[0073] Fig.10 With Fig. 9 A similar schematic diagram shows a second embodiment of the arrangement of the support device 90 on the electrolysis device 10 designed as a module with a module housing 96. This embodiment is based on Fig. 9 design scheme, so refer to Fig. 9 This design is different from the first design in that the plug connector 92 is integral with the housing 94. This eliminates the need for a connecting line 100. The plug connector 92 is located at the end of the housing 94 and protrudes from a plane formed by the housing 94. This allows the plug connector 92 to be connected substantially as in the embodiment of the present invention. Fig. 9As in the first embodiment of the present invention, it is connected to the module, in particular, it is plugged onto the module housing 96.

[0074] Although the principle of the present invention has been explained above based on the application of individual electrolytic cells of an electrolytic device, the principle of the present invention is also equally applicable to electrolytic devices having one or more electrolytic cell blocks, wherein the electrolytic cell blocks may respectively include two or more electrolytic cells. Therefore, as will be readily appreciated by those skilled in the art, aspects associated with the electrolytic cells may be substantially adjusted accordingly and also applied to the corresponding electrolytic cell blocks. Therefore, the processing of the electrolytic cell blocks may also be achieved by convenient and simple adjustments. Of course, a combination of electrolytic cell blocks and a single electrolytic cell may also be provided.

[0075] The examples are only used to explain the present invention, not to limit the present invention.

Claims

1. A support device (90) for an electrolysis device (10) having a plurality of electrolysis cells (12), the support device comprising: - a connecting contact (72) for electrically coupling to a corresponding electrode of the electrolytic cell (12), It is characterized in that - at least one voltage detection unit, the voltage detection unit being used to detect the cell voltage of a corresponding electrolytic cell among the electrolytic cells (12), an evaluation unit (18) which is coupled to at least one voltage detection unit in terms of signal technology for determining at least one cell characteristic or at least one aging state for a respective one of the electrolytic cells (12), and - controllable electronic current source circuits (42), the number of which is equal to the number of the electrolytic cells (12), wherein corresponding ones of the current source circuits (42) are electrically coupled to the electrodes of corresponding ones of the electrolytic cells (12) and direct current is applied individually to the corresponding electrolytic cells (12), and the direct current can be set according to a current source control signal.

2. The support device (90) according to claim 1, characterized in that The voltage detection unit has a plurality of voltage sensors (44), the number of which is equal to the number of the electrolytic cells (12), wherein corresponding voltage sensors among the voltage sensors (44) are electrically coupled to electrodes of corresponding electrolytic cells among the electrolytic cells (12) and are used to detect the cell voltage of the corresponding electrolytic cell (12) and output corresponding voltage signals according to the detected cell voltage.

3. A support device (90) according to any one of the preceding claims, characterized in that At least one current sensor is used to detect the cell current of at least one electrolytic cell in the electrolytic cells (12) and output a current signal according to the detected cell current.

4. The support device (90) according to any one of the preceding claims, characterized in that The evaluation unit (18) detects the cell voltage and the cell current during a predeterminable period of time and determines therefrom a cell property and / or an aging state of the electrolytic cell (12).

5. The support device (90) according to claim 4, characterized in that The evaluation unit (18) determines the cell characteristics and / or aging state of all electrolysis cells (12) coupled to the support device (90) and determines control data for operating states in electrolysis operation, startup and / or shutdown of the electrolysis device (10) based on the determined aging state.

6. A support device (90) according to any one of the preceding claims, characterised in that A separately operable housing (94) has a plug connector (92) for electrically connecting the support device (90) to the electrolytic cell (12).

7. A support device (90) according to any one of the preceding claims, characterized in that The evaluation unit (18) determines the operating status of all electrolysis cells (12) coupled to the evaluation unit (18) and provides a status signal to a higher-level electrolysis control unit (32) based on the determined operating status, so as to control the cell current based on the status signal.

8. An electrolysis device (10) having a plurality of electrolysis cells (12), characterized in that Support device (90) according to any one of the preceding claims.

9. A method for operating an electrolysis system (10) having a plurality of electrolysis cells (12), wherein: For electrical coupling to a support device (90) according to any one of the preceding claims for an electrolysis device (10), respective electrodes of the electrolysis cells (12) are electrically coupled to connection contacts (72) of the support device (90), It is characterized in that The cell voltage of the electrolytic cell (12) is detected by means of at least one voltage detection unit of the support device (90) which is electrically coupled to the connection contact (72), wherein the voltage detection unit provides a corresponding voltage signal as a function of the respectively detected voltage, wherein the voltage signal is evaluated by means of an evaluation unit (18) in order to determine at least one cell characteristic or at least one aging state for the corresponding electrolytic cell (12).

10. The method of claim 9, wherein a respective one of the current source circuits (42) of the support device (90) is electrically coupled to an electrode of a respective one of the electrolytic cells (12), wherein: A direct current is applied individually to the corresponding electrolytic cells (12), and the direct current is set according to a current source control signal.

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