Electrochemical cell system

Abstract

The present invention relates to an electrochemical cell system (100) having a plurality of electrochemical cell stack modules (200) which each have a fuel section (220) and an air section (230), the fuel sections (220) having a fuel supply section (222) for supplying fuel supply gas (BZG) and a fuel discharge section (224) for discharging fuel exhaust gas (BAG), the air sections (230) having an air supply section (232) for supplying supply air (ZL) and an exhaust air discharge section (234) for discharging exhaust air (AL), and having a common central module (300) for supplying the cell stack modules (200) with the operating media fuel supply gas (BZG) and supply air (ZL), and discharging the operating media fuel exhaust gas (BAG) and exhaust air (AL) from the cell stack modules (200), wherein the fuel supply sections (222) each have at least one media heating device (240) for active heating of the fuel supply gas (BZG) in a manner decentralised from the common central module (300).

Description

[0001] Electrochemical cell system

[0002] The present invention relates to an electrochemical cell system and a control method for regulating the operating temperature of electrochemical cell stack modules of an electrochemical cell system.

[0003] It is generally known that electrochemical cell systems are composed of numerous individual components. Particularly when the electrochemical cell system is intended to achieve high performance, for example in the megawatt range, it is common practice to construct it in a modular manner. Individual cell stack modules are combined in such a way that their individual electrochemical capacities are added together, resulting in a correspondingly powerful overall system. Each of these cell stack modules can contain one or more electrochemical cell stacks, thus exhibiting a correspondingly higher or lower module power output.

[0004] In known modular arrangements of electrochemical cell systems, shared components are typically centralized. To reduce complexity and associated costs, so-called Balance-of-Plant (BoP) components are used, which can be shared centrally by all cell stack modules. These components primarily include media preparation and / or media distribution to and from the individual cell stack modules. Furthermore, known solutions typically provide centralized heating and pumping of the individual media streams.

[0005] A disadvantage of known solutions, however, is that for very high electrical power outputs, the number of cell stack modules required for enclosing increases dramatically, potentially reaching several thousand. This leads to complex piping systems, which place high demands on temperature distribution and the uniformity of media distribution. For example, with centralized temperature control in a central module, the temperature loss will vary considerably over different pipe lengths. Therefore, temperature fluctuations and a resulting temperature imbalance across the different cell stack modules can occur in such complex electrochemical cell systems.It can also happen that, due to different pipe lengths and the resulting different pressure loss situations, an undesirable imbalance arises with regard to the mass flows of the individual media to and from the cell stack modules.

[0006] The object of the present invention is to at least partially overcome the disadvantages described above. In particular, it is an object of the present invention to improve the scalability of electrochemical cell systems in a cost-effective and simple manner.

[0007] The foregoing problem is solved by an electrochemical cell system with the features of claim 1 and a control method with the features of claim 15. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the electrochemical cell system according to the invention naturally also apply in connection with the control method according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers, or can refer, to each other.

[0008] The core concept of the invention is based on equipping an electrochemical cell system with a plurality of electrochemical cell stacking modules. Each of these cell stacking modules is equipped with a fuel section and an air section. The fuel sections have a fuel supply section for the supply of fuel gas and a fuel discharge section for the removal of fuel exhaust gas. Similarly, the air sections are equipped with an air supply section for the supply of intake air and an exhaust air discharge section for the removal of exhaust air. Furthermore, such an electrochemical cell system has a common central module for supplying the cell stacking modules with the operating media fuel gas and intake air and for discharging the operating media fuel exhaust gas and exhaust air from the cell stacking modules.

[0009] An electrochemical cell system according to the invention is characterized in that the fuel supply sections each have a media heating device for decentralized, active heating of the fuel supply gas, separate from the common central module. This equips an electrochemical cell system according to the invention with a decentralized heating functionality that can be used in any type of electrochemical cell.

[0010] An electrochemical cell system according to the invention is fundamentally capable of operating in both a so-called fuel cell mode and a so-called electrolysis mode, for example as a SOEC system. Electrolysis mode refers to a situation in which a fuel gas is generated using electrical current. This fuel gas is produced from a feedstock in the form of the fuel gas, for example water vapor, via a chemically controlled reaction and the consumption of electrical current in the electrochemical cell stack modules, and exits the electrochemical cell system as fuel exhaust, for example in the form of hydrogen. In such a case, the electrochemical cell system is configured as an electrolysis system.

[0011] The use of an electrochemical cell system according to the invention for generating electricity is also conceivable. For example, so-called SOFC systems are known, which are similarly used as SOEC systems for electrolysis systems. Accordingly, a fuel cell system is understood to be the use of a targeted and controlled electrochemical reaction that generates electricity. In this case, the fuel gas is supplied to the electrochemical cell stack modules so that the electrochemical reaction for generating electricity can take place there. Of course, electrochemical cell systems according to the present invention can also have both functionalities, so that they are designed to be bidirectional for both modes of operation and can therefore be operated in both directions, i.e., generating electricity and generating fuel gas.

[0012] The core concept of the invention will be particularly advantageous when the electrochemical cell system is one with high electrical power. Specifically, electrochemical cell systems with a total power output of approximately one to ten megawatts are to be considered. For this purpose, a multitude of cell stack modules are used, each cell stack module comprising several electrochemical cell stacks. As will be explained later, each cell stack module can also comprise a multitude of multiple cell stack submodules. Accordingly, a high degree of complexity is required, whereby the desired high electrochemical power output of the entire electrochemical cell system in the megawatt range can be provided by adding the individual electrochemical power capabilities of the individual cell stack modules and / or the individual cell stack submodules.

[0013] While the basic functionality of the electrochemical reaction is ensured by the supply and removal of the operating media, the invention provides a crucial difference compared to known solutions. This difference lies in the provision of a decentralized active heating option for the fuel supply gas. Surprisingly, it has been found that the cost of heating the fuel supply gas depends essentially solely on the total heating power required. Therefore, the required heating surface area and heating power are relevant to the associated costs. Less relevant is the question of whether the desired and required heating power is provided by a single, central, and correspondingly large heating element or by a multitude of correspondingly smaller, decentralized heating elements.Based on this surprising finding, the invention proposes to distribute the individual media heating devices decentrally in the fuel supply sections of the individual cell stack modules and, in particular, to completely dispense with a central heating module in the common central module. This leads to several decisive advantages in the operation of an electrochemical cell system according to the invention.

[0014] Firstly, this results in the heating of the fuel supply gas occurring at a later point in time, significantly further downstream of the common central module and much closer to the respective cell stack module. Consequently, the length of the pipeline between the common central module and the respective cell stack module is bridged with significantly cooler fuel supply gas compared to conventional solutions. This cooler fuel supply gas in these distribution lines leads to two further significant advantages.

[0015] Firstly, the cooler fuel supply gas has a correspondingly lower temperature gradient to the ambient temperature. This lower temperature gradient, in accordance with heat transfer processes, leads to less heat loss despite consistent insulation and pipe length compared to conventional solutions. Simply by shifting the heating element from the central module to the individual cell stack modules, an increase in energy efficiency is achieved without any further design modifications. Because the final heating takes place within the cell stack modules, the shorter pipe length from the heating element to the fuel section of each individual cell stack module results in less heat loss.This can be improved even further if this remaining section of the pipe is additionally insulated with minimal effort, so that only where there is an increased temperature gradient to the ambient temperature is the correspondingly increased thermal insulation present and protects against heat loss.

[0016] Another advantage, directly related to the reduced temperature during the supply to the individual cell stack modules, is a reduction in pressure loss. Due to the physical relationship between pressure, density, and temperature, the density of the fuel supply gas is correspondingly higher compared to conventional solutions, thanks to the reduced temperature during the supply to the individual cell stack modules. This higher density of the fuel supply gas allows for the delivery of the same mass flow rate, i.e., the same quantity of fuel supply gas per unit of time, at a lower flow velocity and therefore lower flow pressure. This directly relates to the resulting pressure loss, as a reduced delivery pressure necessitates a correspondingly lower pressure drop.Particularly in the electrochemical cell systems described in the invention, which have a very large number of up to several thousand individual cell stack modules, even small improvements in pressure loss are associated with a high degree of efficiency improvement. Thus, according to the invention, by increasing the complexity without negatively impacting costs—by arranging the individual media heating devices decentrally instead of in a common central module—a decisive operational advantage can be achieved through the reduced temperature in the supply lines to the individual cell stack modules. This is accompanied by an increase in thermal efficiency as well as an improved pressure loss situation for these supply lines.

[0017] Based on the preceding explanations, it now becomes clear that even very complex electrochemical cell systems equipped with a very large number of individual electrochemical cell stack modules can be operated very efficiently. This leads, in particular, to essentially unrestricted scalability of the electrochemical cell systems, meaning that a virtually unlimited number of electrochemical cell stack modules can be interconnected to provide correspondingly high electrical power for the electrochemical cell system, especially in the megawatt range.

[0018] It can be advantageous if, in an electrochemical cell system according to the invention, the cell stack modules at least partially, and in particular all cell stack modules, comprise two or more electrochemical cell stack submodules, each with two or more electrochemical cell stacks. Each cell stack module includes a fuel distribution section for the fuel supply section, an air distribution section for the air supply section, a fuel exhaust gas collection section for the fuel discharge section, and an exhaust air collection section for the exhaust air discharge section, all for distribution to the individual cell stack submodules. In other words, with very small individual cell stacks and correspondingly low electrochemical power outputs of, for example, 1.5 to 35 kilowatts, this combination can already be implemented at the cell stack module level.In this embodiment, a single cell stack module, which can also be understood as a pre-assembly unit, combines two or more electrochemical cell stack submodules. Each cell stack module has a connection for fuel supply gas, fuel exhaust gas, intake air, and exhaust air. Within the cell stack module, the aforementioned distribution and collection sections are capable of distributing and collecting the respective operating media, so that, from the perspective of the central module, the complexity has been at least partially shifted to the cell stack modules and thus to the cell stack submodules. In this embodiment, preheating and temperature control of the media heating device is now carried out at the module level, so that, in this embodiment, all cell stack submodules of a cell stack module with this semi-decentralized media heating device receive the same temperature control.Here too, as will be explained later, additional variation can be introduced by integrating an air mixing device, which will be discussed later, into the individual cell stack modules specifically for individual cell stack submodules. For example, each cell stack submodule can contain 18 identical cell stacks, each with a power output of 10 kW. The cell stack subsystem assembled in this way accordingly has a combined submodule power output of 180 kW. If two such cell stack submodules are integrated into the cell stack module, then such a cell stack module has a combined module power output of 360 kW.

[0019] Further advantages can arise if, in an electrochemical cell system according to the invention, the air supply sections also feature a media heating device for decentralized active heating of the supply air, separate from the common central module. This further enhances the decentralized heating advantage of the invention, which is the core concept of the present invention. Particularly in electrochemical cell systems where heating the cell stacks on both sides is advantageous, for example, to avoid temperature stresses within the electrochemical cell stack module, this bidirectional active heating can offer benefits. Finally, the advantages of reduced pressure loss and reduced temperature loss are achieved not only for the fuel supply gas but also for the supply air, so that one can speak of a multiplication of the advantages of an electrochemical cell system according to the invention.

[0020] Furthermore, it is advantageous if, in an electrochemical cell system according to the invention, the media heating devices are designed as electrical media heating devices. An electrical media heating device can comprise a simple resistance heating element or similar electrically operated heating elements. The electrical action provides significantly improved controllability and, in particular, complete independence from the temperature of other operating media within the cell system. The media heating device can be operated in the desired and targeted manner, regardless of the current ambient conditions or the current operating conditions of the individual cell stack modules, and thus the temperature of the fuel supply gas for each individual cell stack module can be specifically controlled.If a media heating device with electrical design is also provided in the air supply sections, this also applies accordingly to the control of the temperature of the supply air.

[0021] It is also advantageous if, in an electrochemical cell system according to the invention, the fuel supply sections and / or the air supply sections each have at least one control unit for regulating the mass flow of the respective operating medium in the form of the fuel supply gas and / or the supply air. Such a control unit can be, for example, passively acting orifices or actively acting control valves. Similar to the decentralized control of the temperature of the fuel supply gas, the mass flow of the two aforementioned operating media can also be regulated decentrally. Because decentralized control and, especially at the level of the cell stack modules or even the individual cell stacks, specific control is now possible, it is very easy to compensate for inequalities and the imbalances described several times due to different line lengths.For example, a central compressor unit can be provided in the common central module, which distributes the respective operating medium to the individual lines at a defined pre-pressure, so that a different inlet pressure develops at the respective cell stack module depending on the line length. These different inlet pressures can then be harmonized or balanced by the individual control units being able to compensate for these inequalities that develop over the different line lengths.

[0022] It can be advantageous if, in an electrochemical cell system as described in the preceding paragraph, the control units are located upstream of any media heating devices present in the same path. In other words, the mass flow rate is adjusted before temperature control via the media heating device takes place. Thus, the mass flow rate is controlled first, and then heating occurs. This implies a sequential effect on the respective media path, which is configured as either a supply section or an air supply section. This allows the media heating device to account for temperature changes caused by pressure changes in the control units and to regulate the desired temperature of the respective operating medium even more precisely.Further advantages arise if, in an electrochemical cell system according to the invention, at least some of the control units, and in particular all control units, are designed as passive control units. These can, for example, be designed as pressure orifices, so that the respective media mass flow is reduced passively and thus without adjustment. However, this adjustability can be provided only once, so that, for example, during assembly, construction, or even during the design of the electrochemical cell system, different orifice widths and correspondingly different passive modes of operation can be provided for the different positions of the control units.With very short cable lengths, i.e., with cell stack modules located very close to the common central module, a correspondingly greater reduction in mass flow can be implemented than is the case with cell stack modules located much further away. The lack of controllability is compensated for here by the significantly reduced complexity and more cost-effective design of the control units.

[0023] Furthermore, it is also advantageous if, in an electrochemical cell system according to the invention, at least some of the control units, and in particular all control units, are designed as active control units. An active control unit is, for example, a control valve. This can regulate the mass flow, particularly quantitatively. A combination of active and passive control units is also fundamentally conceivable within the scope of the present invention for adjacent, different, and even identical cell stack modules.

[0024] It is also advantageous if, in an electrochemical cell system according to the invention, a control unit is also arranged in a media path in which a media heating device is located. This means that for each media path to be influenced, both influencing factors, i.e., temperature and mass flow rate, are always combined. The media path refers in particular to the respective fuel supply sections and / or the respective air supply sections.

[0025] Furthermore, it is advantageous if, in an electrochemical cell system according to the invention, a control unit is arranged in a media path that is free of a media heating device. In this variant, it is essentially an opposing arrangement, such that, for example, one media path is equipped with a media heating device and the other media path with a control unit. Here, too, various combinations are fundamentally conceivable for different cell stack modules of one and the same electrochemical cell system.

[0026] Furthermore, it is advantageous if, in an electrochemical cell system according to the invention, the fuel supply sections and / or the air supply sections are identical or substantially identical for all cell stack modules. The uniformity and thus the standardized design of these relevant functional components of the cell stack modules allows for an even more cost-effective construction and, above all, a very free and flexible combination of the cell stack modules depending on the actual power required for the electrochemical cell system. Last but not least, this standardized design also further improves and simplifies the control options.

[0027] Furthermore, it offers additional advantages if, in an electrochemical cell system according to the invention, the cell stack modules are arranged in the air supply sections and / or, in a configuration with two or more cell stack submodules per cell stack module, in the air distribution sections, air mixing devices are arranged for mixing the supply air with ambient air to cool the supply air. Particularly in embodiments where the cell stack modules have two or more cell stack submodules, the temperature can now only be controlled at the module level and thus not specifically for the respective cell stack submodule within a cell stack module. Therefore, from a control perspective, a compromise must be made to distribute the desired temperature across the multiple cell stack submodules without damage or reduction in efficiency.By arranging air mixing devices at the sub-module level, an additional control option can be introduced, ensuring that heating always occurs to the maximum required temperature of all cell stack sub-modules within the respective cell stack module. The cell stack sub-module for which this increased maximum temperature would be too high can then be cooled again using the air mixing device specific to that cell stack sub-module. Thus, the air mixing devices are specifically designed for the respective cell stack sub-module within the cell stack module, while the media heating devices are designed specifically for the cell stack modules and therefore not specific to the cell stack sub-modules. In other words, cooling at the sub-module level allows for fine-tuning of the heating process at the module level.Alternatively or additionally, it is advantageous if gas mixing devices are provided in the fuel supply sections and / or, in the case of a configuration with two or more cell stack submodules per cell stack module, in the fuel distribution sections. These devices allow the fuel supply gas to be mixed with a cooler operating medium to cool the fuel supply gas. This medium could, for example, be hydrogen at ambient temperature and / or water vapor at a temperature below the current operating temperature of the cell stack module.

[0028] Furthermore, it can be advantageous if, in an electrochemical cell system according to the invention, the cell stack modules in the air supply sections and / or, in a configuration with two or more cell stack submodules per cell stack module, in the air distribution sections, have gas mixing control units for mixing the supply air with cooling air to cool the supply air. Alternatively or additionally, it can be advantageous if, in the fuel supply sections and / or, in a configuration with two or more cell stack submodules per cell stack module, in the fuel distribution sections, gas mixing control units for mixing the fuel supply gas with cooling fuel to cool the fuel supply gas. These gas mixing control units combine the functionality of the air mixing devices and / or the gas mixing devices described in the preceding paragraph with the functionality of the control units.In other words, the fine-tuning of the temperature and the regulation of the mass flow are achieved jointly by the gas mixing control units. This makes it possible to dispense with separate control units, such as hot gas dampers, while still retaining the advantages of decentralized control units according to the invention. The gas mixing control units are specifically designed with a passive control option for the mass flow.

[0029] The cooling air can be drawn directly from the environment and / or diverted from the central air module. The ambient temperature may be sufficient as the cooling temperature for the cooling air. However, temperature-controlled treatment of the cooling air within the central module is also conceivable. The cooling fuel is also primarily gaseous and can be supplied, for example, from a fuel tank. Here, the tank temperature of the fuel can be used as the cooling temperature for the cooling fuel. If the fuel, such as hydrogen, is stored under pressure, the cooling of the gas resulting from the expansion of the fuel can be used to further reduce the cooling temperature. The use of fuel exhaust gas, such as water vapor, as a cooling fuel is also conceivable.Such a recirculating gas can be used directly for cooling due to its lower temperature compared to the operating temperature of the cell stack modules.

[0030] The cooling air is preferably distributed from a central cooling air module via cooling air sections to the cell stack modules and / or the cell stack submodules. Additionally or alternatively, the cooling fuel can also be distributed to the cell stack modules and / or the cell stack submodules via cooling fuel sections. When using gas mixing control units, the cell modules and / or the cell stack modules are preferably designed to be free of other control units, free of air mixing devices, and / or free of gas mixing devices.

[0031] A further advantage is that, in an electrochemical cell system according to the invention, the central module is designed to be free or substantially free of central heating devices, in particular free or substantially free of central electrical heating devices. Such freedom from heating devices, especially electrical heating devices, reduces the complexity of the central module. Since a decentralized arrangement of the individual media heating devices is provided, which is virtually cost-neutral, the elimination of such heating devices in the central module can result in cost neutrality.

[0032] Another aspect of the present invention is a control method for regulating the operating temperature of electrochemical cell stack modules in an electrochemical cell system according to the invention. Such a control method is characterized by the following steps:

[0033] - Recording the actual temperature for each cell stack module,

[0034] Comparison of the recorded actual temperature with target temperatures for each cell stack module, decentralized heating of at least the fuel supply gas with the media heating devices in the fuel supply section of the cell stack modules, specifically based on the comparison.

[0035] Such a control method offers the same advantages as those explained in detail with reference to an electrochemical cell system according to the invention. It should also be noted that, in the case of a cell stack module with two or more cell stack submodules, the temperature of each cell stack submodule can also be determined and, for example, used as the basis for the described fine-tuning with an air mixing device.

[0036] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The drawings schematically show:

[0037] Fig. 1 shows an embodiment of an electrochemical cell system according to the invention,

[0038] Fig. 2 shows another embodiment of an electrochemical cell system according to the invention,

[0039] Fig. 3 shows another embodiment of an electrochemical cell system according to the invention,

[0040] Fig. 4 shows another embodiment of an electrochemical cell system according to the invention,

[0041] Fig. 5 shows another embodiment of an electrochemical cell system according to the invention,

[0042] Fig. 6 shows another embodiment of an electrochemical cell system according to the invention,

[0043] Fig. 7 shows a detailed view of a cell stacking module.

[0044] Fig. 8 shows a detailed representation of another embodiment of a cell stacking module and Fig. 9 shows another embodiment of an electrochemical cell system according to the invention.

[0045] Figure 1 schematically shows a very simple embodiment of an electrochemical cell system 100 according to the invention. This is shown here as an example with four separate cell stacking modules 200, although, of course, depending on the desired electrochemical performance, a significantly larger number of several hundred or even up to one thousand cell stacking modules 200 is conceivable. The operating function of such an electrochemical cell system 100 will now be explained in more detail using the cell stacking module 200 arranged on the far left as an example.

[0046] A central module 300 provides both the supply and disposal of media. To maintain operation, a central fuel module 310 distributes fuel supply gas (FSG) to various distribution lines leading to the four cell stack modules 200 shown schematically. On the far left, the fuel supply gas (FSG) is specifically routed to this cell stack module 200 via a media heating device 240, so that it is heated to the desired operating temperature just before entering the cell stack module 200. The heated fuel supply gas (FSG) then enters the cell stack module 200 through the fuel supply section 222 and is fed into the fuel section 220. In the cell stack sub-module 210, which contains two or more electrochemical cell stacks, the electrochemical reaction takes place using supply air (ZL).

[0047] This supply air ZL is also provided by the common central module 300, specifically by the central air module 320, and distributed via corresponding distribution lines to the air supply section 232. Within the cell stack module 200, it is then routed to the air section 230. After the electrochemical conversion has taken place—that is, the generation of electricity in fuel cell operation or the production of fuel in electrolysis operation—the resulting exhaust media, namely the exhaust air AL and the fuel exhaust gas BAG, are routed out of the respective sections 220 and 230 of the cell stack submodule 210 and transferred at the outlets of the cell stack module 200 to the fuel discharge section 224 and the exhaust air discharge section 234. The supply and disposal of these media occurs in the same parallel operation for all other cell stack modules 200.Here it can be clearly seen that all other cell stack modules 200 are also equipped with a decentralized media heating device 240 specific to the respective cell stack module 200, so that the same advantages of decentralized temperature control are also guaranteed for these different cell stack modules 200.

[0048] Figure 2 shows a further development of the embodiments of Figure 1. Here, an additional media heating device 240 is also provided in all air supply sections 232. This allows decentralized active heating not only of the fuel supply gas BZG, but also of the supply air ZL, so that the advantages of reduced temperature loss as well as reduced pressure loss can also be transferred to the supply air ZL.

[0049] Figure 3 shows a further development of the embodiment shown in Figure 2. In addition to controlling the temperature of the respective operating media, the mass flow rate of the respective operating medium can also be controlled by means of control units 250. These are arranged in both the fuel supply sections 222 and the air supply sections 232 and can be configured as either active control valves or passive control orifices. Depending on the distance between the respective cell stack module 200 and the common central module 300, different pressure situations arise depending on the pipe length. This imbalance across the different cell stack modules 200 can now be compensated for and harmonized by these control units 250.

[0050] Figure 4 shows a variation of Figure 3 in which the control units 250 are still provided in both media feeds, i.e., in the fuel feed sections 222 and in the air feed sections 232. However, the media heating device 240 is only provided in the fuel feed section 222 downstream of the control unit 250.

[0051] Figure 5 shows a further reduction of the embodiment shown in Figure 4. Here, the air path, and thus the air supply section 232, is essentially free of media heating devices 240 and control units 250, while the fuel supply section 222 incorporates both functionalities. Figure 6 shows the alternative embodiment of Figure 5. Here, temperature control is provided in the fuel supply section 222 and a control unit 250 is provided in the air supply section 232, thus complementing each other. As Figures 1 to 6 show, the control units 250 and / or the media heating devices 240 are distributed identically or substantially identically for all cell stack modules 200.

[0052] Figures 7 and 8 show further details for more complex cell stacking modules 200. In both figures, the cell stacking module 200 is schematically configured with two separate cell stacking submodules 210, each containing two or more electrochemical cell stacks. Naturally, even more cell stacking submodules 210 can be used, thus further increasing the size of the associated cell stacking module 200. Essentially, within the scope of the present invention, the number of two or more cell stacking submodules 210 per cell stacking module 200, as well as the number of two or more cell stacks per cell stacking submodule 210, can be freely selected according to the required power output of the electrochemical cell system 100.To ensure the division and distribution of the individual operating media within the cell stack module 200, fuel distribution sections 223, air distribution sections 233, fuel exhaust gas collection sections 225, and exhaust air collection sections 235 are provided and arranged within a cell stack module 200. Temperature and mass flow control are not performed at the level of the cell stack submodules 210, but rather at the higher-level intermediate level, which can also be referred to as the hybrid level, of the cell stack modules 200. Thus, decentralized control is still performed with respect to the common central module 300, but more specifically for the individual cell stack submodules 210. This is particularly useful when the control effort needs to be minimized for a very large number of individual, low-power cell stack submodules 210.

[0053] Figure 8 shows a further development in which, despite the reduced temperature controllability, intervention is possible in the actual inlet temperature to the respective air section 230 of the respective cell stack submodule 210. Thus, the corresponding temperature for the supply air ZL can only be set jointly for all cell stack submodules 210 via the associated media heating device 240 in the air supply section 232. Typically, the hottest required operating temperature for the supply air ZL is provided, so that, for example, one of the two cell stack submodules 210 shown here would actually be supplied with excessively hot supply air ZL.However, it is now possible here, with the aid of a very simple and cost-effective air mixing device 260, to cool the supply air ZL, which is actually too hot, for the respective cell stack submodule 210, which has a lower temperature requirement. This thus provides a further means of adjusting the temperature of the supply air ZL, at least in the direction of temperature reduction, even at the level of the cell stack submodules 210. This can also be understood as fine-tuning the temperature for the individual cell stack submodules.

[0054] In addition to fine-tuning the cooling of the supply air with ambient air, cooling the fuel supply gas (FSP) with a cooler operating medium, such as cool fuel supply gas (FSP), is also conceivable. For this purpose, a corresponding gas mixing device 270 can be provided as an alternative or additional to the air mixing device 260. This gas mixing device 270 can be used for heat exchange with a cooler operating medium, such as hydrogen at ambient temperature and / or water vapor at a temperature below the operating temperature of the cell stack module 200.

[0055] Figure 9 shows another embodiment of an electrochemical cell system 100. Here, gas mixing control units 280 were used instead of control units 250 for the cell stack submodules 210. As described previously, decentralized heating of the fuel supply gas BZG and the supply air ZL is carried out via the media heating devices 240. In the embodiment of Figure 9, this occurs at the level of the cell stack modules 200, each of which here comprises two cell stack submodules 210. The gas mixing control units 280 are provided for the individual cell stack submodules 210. By mixing cooling fuel KB into the fuel supply gas BZG and cooling air KL into the supply air ZL, the described fine-tuning of the temperature of the respective operating medium is achieved.The cooling air KL is supplied via cooling air sections 238 and the cooling fuel KB via cooling fuel sections 228 from the central module 300, specifically from a central cooling air module 330 and a central cooling fuel module 340. Figure 9 thus shows the combination of hybrid heating at the level of the cell stack modules 200 and fully decentralized fine-tuning at the level of the cell stack submodules 210. Mass flow control is also performed at the level of the cell stack submodules 210. The electrochemical cell system 100 of Figure 9 can therefore be configured without air mixing devices 260, without gas mixing devices 270, and also without control units 250.

[0056] It should also be noted that the design shown in Figure 9 can be varied. For example, the gas mixing control units 280 can also be used at the level of the cell stacks 200, thus enabling hybrid control. Use with simpler cell stack modules 200 without multiple cell stack submodules 210 is also possible.

[0057] The preceding explanation of the embodiments describes the present invention exclusively by way of examples.

[0058] Reference symbol list

[0059] 100 Electrochemical cell system

[0060] 200 cell stack module

[0061] 210 cell stack submodule

[0062] 220 Fuel section

[0063] 222 Fuel supply section

[0064] 223 Fuel distribution section

[0065] 224 Fuel discharge section

[0066] 225 Fuel exhaust gas collection section

[0067] 228 Cooling fuel section

[0068] 230 Air section

[0069] 232 Air supply section

[0070] 233 Air distribution section

[0071] 234 Exhaust air discharge section

[0072] 235 Exhaust air collection section

[0073] 238 Cooling air section

[0074] 240 Media heating device

[0075] 250 control unit

[0076] 260 air mixing device

[0077] 270 Gas mixing device

[0078] 280 Gas mixing control unit

[0079] 300 Central module

[0080] 310 Central Fuel Module

[0081] 320 Central Air Module

[0082] 330 Central cooling air module

[0083] 340 Central cooling fuel module

[0084] BZG fuel supply gas

[0085] BAG fuel exhaust

[0086] ZL supply air

[0087] AL exhaust air

[0088] KL Cooling Air

[0089] KB Cooling fuel

Claims

Patent claims 1. Electrochemical cell system (100) comprising a plurality of electrochemical cell stacking modules (200) each with a fuel section (220) and an air section (230), the fuel sections (220) comprising a fuel supply section (222) for supplying fuel supply gas (FSG) and a fuel discharge section (224) for removing fuel exhaust gas (FEG), the air sections (230) comprising an air supply section (232) for supplying supply air (SLP) and an exhaust air discharge section (234) for removing exhaust air (EA), further comprising a common central module (300) for supplying the cell stacking modules (200) with the operating media fuel supply gas (FSG) and supply air (SLP) and for removing the operating media fuel exhaust gas (FEG) and exhaust air (EA) from the cell stacking modules (200), characterized in that,that the fuel supply sections (222) each have at least one media heating device (240) for active heating of the fuel supply gas (FSP) decentrally from the common central module (300).

2. Electrochemical cell system (100) according to claim 1, characterized in that the cell stack modules (200) at least partially, in particular all cell stack modules (200), have two or more electrochemical cell stack submodules (210) each with two or more electrochemical cell stacks, wherein in each cell stack module (200) the fuel supply section (222) via fuel distribution sections (223), the air supply section (232) via air distribution sections (233), the fuel discharge section (224) via fuel exhaust gas collection sections (225) and the exhaust air discharge section (234) via exhaust air collection sections (235) is divided among the individual cell stack submodules (210).

3. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the air supply sections (232) also have a media heating device (240) for decentralized active heating of the supply air (ZL) from the common central module (300).

4. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the media heating devices (240) are designed as electrical media heating devices (240).

5. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the fuel supply sections (222) and / or the air supply sections (232) each have at least one control unit (250) for controlling the mass flow of the respective operating medium in the form of the fuel supply gas (FSG) and / or the supply air (SEA).

6. Electrochemical cell system (100) according to claim 5, characterized in that the control units (250) are located upstream of the media heating devices (240) in the same media path.

7. Electrochemical cell system (100) according to one of claims 5 or 6, characterized in that at least some of the control units (250), in particular all control units (250), are designed as passive control units (250).

8. Electrochemical cell system (100) according to one of claims 5 to 7, characterized in that at least some of the control units (250), in particular all control units (250), are designed as active control units (250).

9. Electrochemical cell system (100) according to one of claims 5 to 8, characterized in that a control unit (250) is also arranged in a media path in which a media heating device (240) is arranged.

10. Electrochemical cell system (100) according to one of claims 5 to 9, characterized in that a control unit (250) is arranged in a media path which is free of a media heating device (240).

11. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the fuel supply sections (222) and / or the air supply sections (232) are identical or substantially identical for all cell stack modules (200).

12. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the cell stack modules (200) in the air supply sections (232) and / or in an embodiment with two or more cell stack submodules (210) per cell stack module (200) in the air distribution sections (233) have air mixing devices (260) for mixing the supply air (ZL) with ambient air for cooling the supply air (ZL), and / or in the fuel supply sections (222) and / or in an embodiment with two or more cell stack submodules (210) per cell stack module (200) in the fuel distribution sections (223), gas mixing devices (270) for mixing the fuel supply gas (BZG) with a cooler operating medium for cooling the fuel supply gas (BZG).

13. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the cell stack modules (200) in the air supply sections (232) and / or in a configuration with two or more cell stack submodules (210) per cell stack module (200) in the air distribution sections (233) have gas mixing control units (280) for mixing the supply air (ZL) with cooling air (KL) for cooling the supply air (ZL), and / or in the fuel supply sections (222) and / or in a configuration with two or more cell stack submodules (210) per cell stack module (200) in the fuel distribution sections (223), gas mixing control units (280) for mixing the fuel supply gas (BZG) with cooling fuel (KB) for cooling the fuel supply gas (BZG).

14. Electrochemical cell system (100) according to one of the preceding claims, characterized in that the central module (300) is free or substantially free of central electrical heating devices, in particular free or substantially free of central heating devices.

15. Control method for controlling the operating temperature of electrochemical cell stack modules (200) in an electrochemical cell system (100) with the features of one of claims 1 to 13, characterized by the following steps: Recording an actual temperature for each cell stack module (200), - Comparison of the recorded actual temperatures with target temperatures for each cell stack module (200), - Decentralized heating of at least the fuel supply gas (FSG) with the media heating devices in the fuel supply sections (222) of the cell stack modules (200), specifically based on the comparison.

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