Flat tube type solid oxide electrolysis reactor

Abstract

The invention discloses a flat tube type solid oxide electrolysis stack. The flat tube type solid oxide electrolysis stack comprises an electrolysis galvanic pile; the electrolytic stack comprises symmetrical flat tube type solid oxide electrolytic cells which are arranged in a stacked manner; each electrolytic cell comprises a supporting layer with a fuel channel, an electrolyte layer and an air electrode layer which are symmetrically distributed on the upper surface and the lower surface of the supporting layer, and a breathable conductive net which is arranged on the surface of the air electrode layer and communicates with the air electrode layers on the two surfaces of the electrolytic cell; the fuel electrode cover plates are arranged at the two ends of the electrolysis galvanic pile, are connected with the supporting layer and comprise gas cavities which are in sealed connection with the fuel channels; a gas transmission pipeline; and the air electrode cover plates are arranged on and fixedly connected with the upper surface and the lower surface of the electrolysis galvanic pile. According to the scheme disclosed by the invention, the plurality of electrolytic tanks are stacked to form the electric pile, the fuel electrode cover plates are arranged at the two ends of the electric pile, and for the air electrode, only the breathable conductive net is arranged on the surface of the air electrode, and the fixedly connected air electrode cover plates are arranged on the upper surface and the lower surface of the electric pile; the flat tube type solid oxide electrolysis reactor is simple and compact in structure.

Description

Technical Field

[0001] The present application relates to the technical field of solid oxide electrolytic cells, and more specifically, to a flat tube solid oxide electrolytic stack. Background Art

[0002] SOEC (solid oxide electrolysis cell) is a high-efficiency, low-cost, low-pollution, all-solid-state energy conversion device that can efficiently convert surplus electricity into chemical energy and store it in large quantities, thereby saving electricity and improving the utilization rate of renewable energy.

[0003] At present, SOECs are usually integrated by stacking them in series to form a stack in order to increase the effective reaction area of ​​the battery. The existing flat tube solid oxide stack follows the design of the SOFC (solid oxide fuel cell) stack: the sealing of the fuel electrode and the air electrode is ensured at the same time, that is, the corresponding sealing structure and gas flow channel are respectively provided for the fuel electrode and the air electrode. Moreover, the existing flat tube solid oxide stack is to seal the fuel electrode of each single cell separately, and then stack the single cells with sealed fuel electrodes together. The above-mentioned flat tube solid oxide stack has a complex and loose structure.

[0004] In summary, how to reduce the complexity of the flat tube solid oxide electrolysis stack and improve the compactness of the flat tube solid oxide electrolysis stack is a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a flat tube solid oxide electrolysis stack, which is used to reduce the complexity of the flat tube solid oxide electrolysis stack and improve the compactness of the flat tube solid oxide electrolysis stack.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A flat tube solid oxide electrolysis stack, comprising:

[0008] An electrolytic stack; the electrolytic stack comprises symmetrical flat tube solid oxide electrolytic cells arranged in layers, the symmetrical flat tube solid oxide electrolytic cells comprising a support layer with a fuel channel, an electrolyte layer and an air electrode layer symmetrically distributed on the upper and lower surfaces of the support layer, and a permeable conductive mesh arranged on the surface of the air electrode layer and connecting the air electrode layers on both sides of the symmetrical flat tube solid oxide electrolytic cells;

[0009] A fuel electrode cover plate disposed at both ends of the electrolytic stack, connected to the support layer and comprising an air cavity sealed and connected to the fuel channel;

[0010] A gas delivery pipeline connected to the gas cavity of the fuel electrode cover plate;

[0011] The air electrode cover plate is arranged on the upper surface and the lower surface of the electrolytic cell stack and is fixedly connected.

[0012] Preferably, a groove for accommodating the symmetrical flat-tube solid oxide electrolytic cell is provided on a surface of the fuel electrode cover plate that contacts the electrolytic cell stack;

[0013] An air hole connected to the air cavity and the fuel channel is provided at the bottom of the groove.

[0014] Preferably, a sealant is provided in the gap between the groove and the symmetrical flat-tube solid oxide electrolytic cell.

[0015] Preferably, a porous metal layer or a foam metal layer is provided between the fuel electrode cover plate and the electrolytic cell stack.

[0016] Preferably, a porous nickel layer or a foamed nickel layer is provided between the fuel electrode cover plate and the electrolytic cell stack.

[0017] Preferably, the air electrode cover plates arranged on the upper surface and the lower surface of the electrolytic cell stack are fixedly connected by screws.

[0018] Preferably, the breathable conductive mesh is a silver mesh.

[0019] Preferably, the symmetrical flat-tube solid oxide electrolytic cell further comprises an active fuel electrode layer which is symmetrically distributed on the upper and lower surfaces of the support layer and is located between the support layer and the electrolyte layer.

[0020] Preferably, the symmetrical flat-tube solid oxide electrolytic cell further comprises a barrier layer which is symmetrically distributed on the upper and lower surfaces of the support layer and is located between the electrolyte layer and the air electrode layer.

[0021] Preferably, the electrolyte layer completely covers the support layer, the air electrode layer is not provided in the edge area of ​​the electrolyte layer surface close to the fuel electrode cover plate, and the air electrode layer is provided in the area of ​​the electrolyte layer surface other than the edge area close to the fuel electrode cover plate.

[0022] The present application provides a flat tube solid oxide electrolysis stack, comprising: an electrolysis stack; the electrolysis stack may include a symmetrical flat tube solid oxide electrolysis cell arranged in layers, the symmetrical flat tube solid oxide electrolysis cell may include a support layer with a fuel channel, an electrolyte layer and an air electrode layer symmetrically distributed on the upper and lower surfaces of the support layer, a breathable conductive mesh arranged on the surface of the air electrode layer and connecting the air electrode layer on both sides of the symmetrical flat tube solid oxide electrolysis cell; a fuel electrode cover plate arranged at both ends of the electrolysis stack, connected to the support layer and including a sealed connection with the fuel channel; a gas transmission pipeline connected to the air cavity of the fuel electrode cover plate; an air electrode cover plate arranged on the upper and lower surfaces of the electrolysis stack and fixedly connected.

[0023] The above technical solution disclosed in the present application stacks a plurality of symmetrical flat-tube solid oxide electrolytic cells to form an electrolytic stack and arranges fuel electrode covers at both ends of the electrolytic stack, without the need to seal the fuel electrode of each electrolytic cell separately and then stack them to form an electrolytic stack. For the air electrode, only a breathable conductive mesh is arranged on the surface of the air electrode to connect the air electrode layer on both sides of the symmetrical flat-tube solid oxide electrolytic cell, and a fixedly connected air electrode cover is arranged on the upper and lower surfaces of the electrolytic stack to ensure that the gas generated by the air electrode electrolysis can be smoothly diffused, and there is no need to arrange an air electrode sealing device and a gas flow channel. Therefore, the flat-tube solid oxide electrolytic stack of the present application has a simple and compact structure, a small size, and occupies a small space, which is convenient for large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0025] Figure 1 A schematic diagram of the structure of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application;

[0026] Figure 2 A schematic diagram of a cross section of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application at one viewing angle;

[0027] Figure 3 A schematic diagram of a cross section of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application from another perspective;

[0028] Figure 4 A cross-sectional view of a symmetrical flat tube solid oxide electrolytic cell without a gas-permeable conductive mesh provided in an embodiment of the present application;

[0029] Figure 5 A schematic diagram of a symmetrical flat tube solid oxide electrolytic cell without a gas-permeable conductive mesh provided in an embodiment of the present application at one viewing angle;

[0030] Figure 6 A schematic diagram of a symmetrical flat tube solid oxide electrolytic cell with a gas-permeable conductive mesh provided in an embodiment of the present application at one viewing angle;

[0031] Figure 7 A schematic diagram of a breathable conductive mesh provided in an embodiment of the present application;

[0032] Figure 8A schematic diagram of a fuel electrode cover provided in an embodiment of the present application at a certain viewing angle;

[0033] Fig. 9 A schematic cross-sectional view of a fuel electrode cover plate provided in an embodiment of the present application;

[0034] Fig.10 A schematic plan view of a fuel electrode cover plate in contact with an electrolytic cell stack provided in an embodiment of the present application;

[0035] Fig.11 A schematic diagram of a porous structure on a fuel electrode cover plate provided in an embodiment of the present application;

[0036] Fig.12 A cross-sectional view of another symmetrical flat tube solid oxide electrolytic cell without a gas-permeable conductive mesh provided in an embodiment of the present application;

[0037] Fig.13 The SOEC mode IV polarization curves at different water bath temperatures provided in the examples of the present application;

[0038] Fig.14 A curve diagram showing the change of voltage and hydrogen production under long-term constant current provided in an embodiment of the present application;

[0039] The reference numerals are as follows:

[0040] 1- symmetrical flat tube solid oxide electrolytic cell, 10- fuel channel, 11- support layer, 12- electrolyte layer, 13- air electrode layer, 14- active fuel electrode layer, 15- barrier layer, 2- breathable conductive mesh, 3- fuel electrode cover plate, 31- air cavity, 32- groove, 33- pore, 4- gas pipeline, 5- air electrode cover plate, 6- screw. DETAILED DESCRIPTION

[0041] At present, SOECs are usually integrated by stacking them in series to form a stack in order to increase the effective reaction area of ​​the battery. The existing flat tube solid oxide stack follows the design of the SOFC (solid oxide fuel cell) stack: the sealing of the fuel electrode and the air electrode is ensured at the same time, that is, the corresponding sealing structure and gas flow channel are respectively provided for the fuel electrode and the air electrode. Moreover, the existing flat tube solid oxide stack is to seal the fuel electrode of each single cell separately, and then stack the single cells with sealed fuel electrodes together. The above-mentioned flat tube solid oxide stack has a complex and loose structure.

[0042] To this end, the present application provides a flat tube solid oxide electrolysis stack, which is used to reduce the complexity of the flat tube solid oxide electrolysis stack and improve the compactness of the flat tube solid oxide electrolysis stack.

[0043] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0044] See also Figures 1 to 7 ,in, Figure 1 The schematic diagram of the structure of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application is shown. Figure 2 A schematic diagram of a cross section of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application at one viewing angle is shown. Figure 3 A schematic diagram of a cross section of a flat tube solid oxide electrolysis stack provided in an embodiment of the present application from another perspective is shown. Figure 4 A cross-sectional view of a symmetrical flat tube solid oxide electrolytic cell without a gas-permeable conductive mesh provided in an embodiment of the present application is shown. Figure 5 A schematic diagram of a symmetrical flat tube solid oxide electrolytic cell without a gas permeable conductive mesh provided in an embodiment of the present application at one viewing angle is shown. Figure 6 A schematic diagram of a symmetrical flat tube solid oxide electrolytic cell with a gas-permeable conductive mesh provided in an embodiment of the present application at one viewing angle is shown. Figure 7 A schematic diagram of a gas-permeable conductive mesh provided in an embodiment of the present application is shown. A flat tube solid oxide electrolysis stack provided in an embodiment of the present application may include:

[0045] The electrolytic stack; the electrolytic stack may include a stacked symmetrical flat tube solid oxide electrolytic cell 1, which may include a support layer 11 with a fuel channel 10, an electrolyte layer 12 and an air electrode layer 13 symmetrically distributed on the upper and lower surfaces of the support layer 11, and a permeable conductive mesh 2 disposed on the surface of the air electrode layer 13 and connecting the air electrode layer 13 on both sides of the symmetrical flat tube solid oxide electrolytic cell 1;

[0046] A fuel electrode cover plate 3 is arranged at both ends of the electrolytic stack, connected to the support layer 11 and includes a fuel electrode cover plate 3 which is sealed and connected to the fuel channel 10;

[0047] A gas delivery pipeline 4 connected to the gas cavity 31 of the fuel electrode cover plate 3;

[0048] The air electrode cover plate 5 is arranged on the upper surface and the lower surface of the electrolytic cell stack and is fixedly connected.

[0049] The flat tube solid oxide electrolysis stack provided in the present application may include an electrolysis stack, a fuel electrode cover plate 3 arranged at both ends of the electrolysis stack, a gas pipeline 4 arranged on the fuel electrode cover plate 3, and an air electrode cover plate 5 arranged on the upper surface and the lower surface of the electrolysis stack. That is, the fuel electrode cover plate 3 includes a first fuel electrode cover plate located at the first end of the electrolysis stack and a second fuel electrode cover plate located at the second end of the electrolysis stack. The first end of the electrolysis stack is consistent with the first end of the fuel channel 10 in the symmetrical flat tube solid oxide electrolysis cell 1, and the second end of the electrolysis stack is consistent with the second end of the fuel channel 10 in the symmetrical flat tube solid oxide electrolysis cell 1. The gas pipeline 4 includes a first gas pipeline arranged on the first fuel electrode cover plate and a second gas pipeline arranged on the second fuel electrode cover plate. The air electrode cover plate 5 includes a first air electrode cover plate located on the upper surface of the electrolysis stack and a second air electrode cover plate located on the lower surface of the electrolysis stack, and the first air electrode cover plate is fixedly connected to the second air electrode cover plate. Among them, the first fuel electrode cover plate, the second fuel electrode cover plate, the first air electrode cover plate and the second air electrode cover plate are all conductive. Specifically, these cover plates can all be steel plates.

[0050] The electrolytic stack includes symmetrical flat-tube solid oxide electrolytic cells 1 stacked in layers, that is, the electrolytic stack is formed by stacking a plurality of symmetrical flat-tube solid oxide electrolytic cells 1 in sequence, wherein, in the electrolytic stack, two adjacent symmetrical flat-tube solid oxide electrolytic cells 1 are in contact with each other, that is, the flat-tube solid oxide electrolytic stack provided in the present application is a parallel arrangement of symmetrical flat-tube solid oxide electrolytic cells 1. Since the resistance of the solid oxide electrolytic cell during actual operation mainly comes from the air electrode, appropriately sacrificing the fuel electrode current collecting area and increasing the air electrode current collecting area can effectively improve the performance of the stack, therefore, the flat-tube parallel double air electrode SOEC stack provided in the present application can improve the efficiency and performance of the stack.

[0051] Each symmetrical flat tube solid oxide electrolytic cell 1 includes a support layer 11 (i.e., a supporting anode) as a fuel electrode and provided with a fuel channel 10, an electrolyte layer 12 and an air electrode layer 13 symmetrically distributed on the upper and lower surfaces of the support layer 11, and a breathable conductive mesh 2 arranged on the surface of the air electrode layer 13 and connecting the air electrode layer 13 on the upper and lower surfaces of the symmetrical flat tube solid oxide electrolytic cell 1, wherein the number of fuel channels 10 can be multiple, and the fuel channel 10 is arranged in the support layer 11 and penetrates the support layer 11 (specifically penetrates the long side of the support layer 11). The electrolyte layer 12 of the symmetrical flat tube solid oxide electrolytic cell 1 specifically includes a first electrolyte layer and a second electrolyte layer, the first electrolyte layer is located on the upper surface of the support layer 11, and the second electrolyte layer is located on the lower surface of the support layer 11. The air electrode layer 13 of the symmetrical flat tube solid oxide electrolytic cell 1 specifically includes a first air electrode layer and a second air electrode layer, the first air electrode layer is located on the upper surface of the first electrolyte layer, and the second air electrode layer is located on the lower surface of the second electrolyte layer. The air-permeable conductive mesh 2 wraps around the side of the symmetrical flat tube solid oxide electrolytic cell 1 and the upper surface of the first air electrode layer and the lower surface of the second air electrode layer, so that the first air electrode layer and the second air electrode layer of each symmetrical flat tube solid oxide electrolytic cell 1 are electrically connected through the conductivity of the air-permeable conductive mesh 2, and two adjacent symmetrical flat tube solid oxide electrolytic cells 1 in the electrolytic cell stack can be electrically conductive. At the same time, the gas generated by the air electrode of the flat tube solid oxide electrolytic stack can be released through the air permeability of the air-permeable conductive mesh 2. In the symmetrical flat tube solid oxide electrolytic cell 1, the support layer 11 can be nickel oxide and 3YSZ (3% Y2O3 doped ZrO2), the electrolyte layer 12 can be 8YSZ, the thickness of which can be 10μm-15μm, and the air electrode layer 13 can be LSCF (La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3-δ )-GDC(Gd 0.1 Ce 0.9 O 2-δ , gadolinium oxide-doped cerium oxide), the thickness of which can be 10μm-20μm.

[0052] The symmetrical flat tube solid oxide electrolytic cell 1 not only has upper and lower regions that can be used as electrochemical reaction zones to improve fuel utilization and fully utilize the device potential, but also the stress generated by thermal expansion and contraction in the electrolytic cell is symmetrical. Therefore, it is not easy to deform due to thermal stress, which can greatly reduce warping and cracking.

[0053] The fuel electrode cover plate 3 is connected to the support layer 11 (specifically, the end surface of the support layer 11) of each symmetrical flat tube solid oxide electrolytic cell 1 in the electrolytic stack. The fuel electrode cover plate 3 includes an air cavity 31, which is sealed and connected to the fuel channel 10 in the support layer 11 in each symmetrical flat tube solid oxide electrolytic cell 1 to prevent leakage of fuel gas and generated gas, and the existence of the air cavity 31 can facilitate the dispersion of fuel gas. The gas transmission pipeline 4 is arranged on the fuel electrode cover plate 3 and is connected to the air cavity 31 on the fuel electrode cover plate 3.

[0054] Among them, one of the first gas pipeline and the second gas pipeline is used to transport fuel gas to the flat tube solid oxide electrolysis stack, and the other gas pipeline can be used to output the gas generated by electrolysis of the support layer 11 in the symmetrical flat tube solid oxide electrolysis cell 1. Taking the first gas pipeline as an example of inputting water vapor to the flat tube solid oxide electrolysis stack, the water vapor can enter the fuel channel 10 of the support layer 11 through the first gas pipeline and the air cavity 31 in the first fuel electrode cover plate. Under the action of voltage applied by the fuel electrode cover plate 3 and the air electrode cover plate 5, the flat tube solid oxide electrolysis stack can electrolyze the water vapor to produce hydrogen (hydrogen is produced in the support layer 11) and oxygen (oxygen is produced in the air electrode layer 13). Hydrogen can be transported out through the fuel channel 10 in the support layer 11, the air cavity 31 in the second fuel electrode cover plate and the second gas pipeline, and oxygen can be released through the air-permeable conductive mesh 2.

[0055] From the above, it can be seen that the present application is to stack a plurality of symmetrical flat tube type solid oxide electrolytic cells 1 to form an electrolytic stack, and to set fuel electrode cover plates 3 which are sealed and connected to the symmetrical flat tube type solid oxide electrolytic cells 1 at both ends of the electrolytic stack. Therefore, the flat tube type solid oxide electrolytic stack in the present application only needs two fuel electrode cover plates 3. Compared with the existing flat tube type solid oxide stack in which the fuel electrode plates are set for each electrolytic cell separately and then the electrolytic cells with the fuel electrode plates are integrated together, the present application can reduce the number of fuel electrode cover plates 3 set, and can reduce the complexity of the setting of the fuel electrode cover plates 3 and the electrolytic stack, so that the overall structure of the flat tube type solid oxide electrolytic stack is simple and compact. In addition, the present application takes into account that the flat tube solid oxide electrolysis stack does not require air or the like as a raw material during operation. Therefore, the present application only sets a breathable conductive mesh 2 and an air electrode cover plate 5 on the air electrode side of the flat tube solid oxide electrolysis stack to ensure current collection and air permeability. Compared with the existing flat tube solid oxide electrolysis stack that uses the SOFC design, the present application does not set up complex air ducts and flow channels, etc. Therefore, the complexity of the flat tube solid oxide electrolysis stack can be reduced, making the flat tube solid oxide electrolysis stack simpler and more compact.

[0056] The above technical solution disclosed in the present application stacks a plurality of symmetrical flat-tube solid oxide electrolytic cells to form an electrolytic stack and arranges fuel electrode covers at both ends of the electrolytic stack, without the need to seal the fuel electrode of each electrolytic cell separately and then stack them to form an electrolytic stack. For the air electrode, only a breathable conductive mesh is arranged on the surface of the air electrode to connect the air electrode layer on both sides of the symmetrical flat-tube solid oxide electrolytic cell, and a fixedly connected air electrode cover is arranged on the upper and lower surfaces of the electrolytic stack to ensure that the gas generated by the air electrode electrolysis can be smoothly diffused, and there is no need to arrange an air electrode sealing device and a gas flow channel. Therefore, the flat-tube solid oxide electrolytic stack of the present application has a simple and compact structure, a small size, and occupies a small space, which is convenient for large-scale application.

[0057] See also Figures 8 to 11 ,in, Figure 8 A schematic diagram of a fuel electrode cover provided in an embodiment of the present application at a certain viewing angle is shown. Fig. 9 A cross-sectional schematic diagram of a fuel electrode cover plate provided in an embodiment of the present application is shown. Fig.10 A schematic plan view of a fuel electrode cover plate in contact with an electrolytic cell stack provided in an embodiment of the present application is shown. Fig.11 A schematic diagram of a porous structure on a fuel electrode cover provided in an embodiment of the present application is shown. A flat tube solid oxide electrolysis stack provided in an embodiment of the present application, a side of the fuel electrode cover 3 in contact with the electrolysis stack is provided with a groove 32 for accommodating a symmetrical flat tube solid oxide electrolysis cell 1;

[0058] An air hole 33 connected to the air cavity 31 and the fuel channel 10 is provided at the bottom of the groove 32 .

[0059] In the present application, the fuel electrode cover plate 3 is provided with grooves 32 corresponding to each symmetrical flat tube type solid oxide electrolytic cell 1 in the electrolytic cell stack on one side thereof, and these grooves 32 are used to accommodate each symmetrical flat tube type solid oxide electrolytic cell 1 in the electrolytic cell stack, that is, to be inserted into the support layer 11 of each symmetrical flat tube type solid oxide electrolytic cell 1 in the electrolytic cell stack, so that the fuel electrode cover plate 3 is connected to the end surface of the support layer 11 of each symmetrical flat tube type solid oxide electrolytic cell 1. The bottom of the groove 32 is conductive.

[0060] In addition, the bottom of each groove 32 is provided with an air hole 33 connected to the air cavity 31 in the fuel electrode cover plate 3 and the fuel channel 10 in the symmetrical flat tube solid oxide electrolytic cell 1. The number of air holes 33 arranged at the bottom of each groove 32 is equal to the number of fuel channels 10 in the symmetrical flat tube solid oxide electrolytic cell 1. Each air hole 33 corresponds to a fuel channel 10, and the air hole 33 is sealed and connected to the fuel channel 10 to prevent gas leakage.

[0061] The fuel electrode cover plate 1 may specifically include a steel plate and a first flat plate fixed on the steel plate (specifically fixed by screws or the like), wherein the surface of the steel plate in contact with the first flat plate may be provided with an air cavity groove, and the air cavity groove and the first flat plate may form an air cavity 31 of the fuel electrode cover plate 1, and a groove 32 may be provided on one side of the first flat plate away from the steel plate, and an air hole 33 may be provided at the bottom of the groove 32. Of course, the fuel electrode cover plate 1 may also be in other structural forms.

[0062] In an embodiment of the present application, a flat tube solid oxide electrolytic stack is provided, wherein a sealant is provided in the gap between the groove and the symmetrical flat tube solid oxide electrolytic cell 1 .

[0063] In the present application, in order to ensure the sealing between the fuel electrode cover plate 3 and the symmetrical flat tube solid oxide electrolytic cell 1, a sealant can be set in the gap between the groove 32 set on the fuel electrode cover plate 3 and the symmetrical flat tube solid oxide electrolytic cell 1, so as to use the sealant for sealing, thereby ensuring that the fuel electrode gas can only enter the symmetrical flat tube solid oxide electrolytic cell 1 from the air cavity 31 through the air hole 33.

[0064] The sealant may be a glass sealant, and after the two fuel electrode cover plates 3 are assembled, pressure sintering may be performed to fix the fuel electrode cover plates 3 and the symmetrical flat tube solid oxide electrolytic cell 1 through the adhesiveness of the sealant.

[0065] In a flat tube solid oxide electrolytic stack provided in an embodiment of the present application, a porous metal layer or a foam metal layer is provided between the fuel electrode cover plate 3 and the electrolytic stack.

[0066] In the present application, considering that the fuel electrode cover plate 3 is generally a steel plate and the symmetrical flat tube solid oxide electrolysis cell 1 is generally a ceramic, in order to enhance the contact between the fuel electrode cover plate 3 and the symmetrical flat tube solid oxide electrolysis cell 1 while ensuring conductivity and air permeability, a porous metal layer or a foam metal layer can be arranged between the fuel electrode cover plate 3 and the electrolysis stack to ensure the contact between the fuel electrode cover plate 3 and the symmetrical flat tube solid oxide electrolysis cell 1 while ensuring conductivity and air permeability between the two.

[0067] In a flat tube solid oxide electrolytic stack provided in an embodiment of the present application, a porous nickel layer or a foamed nickel layer is provided between the fuel electrode cover plate 3 and the electrolytic stack.

[0068] In the present application, a porous nickel layer or a foamed nickel layer may be provided between the fuel electrode cover plate 3 and the electrolytic cell stack.

[0069] In a flat tube solid oxide electrolysis stack provided in an embodiment of the present application, air electrode cover plates 5 arranged on the upper surface and the lower surface of the electrolysis stack are fixedly connected by screws 6 .

[0070] In the present application, the air electrode cover plates 5 arranged on the upper and lower surfaces of the electrolytic stack can be connected and fixed by screws 6, that is, the first air electrode cover plate and the second air electrode cover plate can be fixedly connected by screws 6 to ensure the reliability of the connection.

[0071] In a flat tube solid oxide electrolysis stack provided in an embodiment of the present application, the air-permeable conductive mesh 2 is a silver mesh.

[0072] In the present application, considering that the flat tube solid oxide electrolysis stack works in a high temperature environment, and when the fuel gas is water vapor, the air pole produces oxygen, therefore, the air permeable conductive mesh 2 provided in the symmetrical flat tube solid oxide electrolysis cell 1 can be a silver mesh. The silver mesh has the characteristics of high temperature resistance and is not easy to oxidize. Alternatively, a platinum mesh can be used as the air permeable conductive mesh 2.

[0073] See also Fig.12 , which shows a cross-sectional view of another symmetrical flat tube solid oxide electrolysis cell without a gas permeable conductive mesh provided in an embodiment of the present application. A flat tube solid oxide electrolysis stack provided in an embodiment of the present application, the symmetrical flat tube solid oxide electrolysis cell 1 may also include an active fuel electrode layer 14 symmetrically distributed on the upper and lower surfaces of the support layer 11 and located between the support layer 11 and the electrolyte layer 12.

[0074] In the present application, the symmetrical flat tube solid oxide electrolysis cell 1 may also include an active fuel electrode layer 14 symmetrically distributed on the upper and lower surfaces of the support layer 11 and located between the support layer 11 and the electrolyte, that is, the symmetrical flat tube solid oxide electrolysis cell 1 may include a first active fuel electrode layer and a second active fuel electrode layer, wherein the first active fuel electrode layer is arranged between the support layer 11 and the first electrolyte layer, and the second active fuel electrode layer is arranged between the support layer 11 and the second electrolyte layer.

[0075] The active fuel electrode layer 14 can catalyze the reaction of the fuel electrode (i.e., the support layer 11) and conduct ions (such as oxygen ions) and electrons generated by the fuel electrode. The active fuel electrode layer 14 can be specifically NiO / 8YSZ (nickel oxide mixed with 8% Y2O3 doped ZrO2), and the thickness of each active fuel electrode layer 14 can be 15μm-20μm. The active fuel electrode layer 14 can be specifically obtained by screen printing.

[0076] An embodiment of the present application provides a flat tube solid oxide electrolysis stack. The symmetrical flat tube solid oxide electrolysis cell 1 may further include a barrier layer 15 symmetrically distributed on the upper and lower surfaces of the support layer 11 and located between the electrolyte layer 12 and the air electrode layer 13 .

[0077] In the present application, the symmetrical flat tube solid oxide electrolytic cell 1 may further include a barrier layer 15 symmetrically distributed on the upper and lower surfaces of the support layer 11 and located between the electrolyte layer 12 and the air electrode layer 13. That is, the symmetrical flat tube solid oxide electrolytic cell 1 may include a first barrier layer and a second barrier layer, wherein the first barrier layer is arranged between the first air electrode layer and the first electrolyte layer, and the second barrier layer is arranged between the second air electrode layer and the second electrolyte layer.

[0078] The barrier layer 15 is used to prevent mutual diffusion between the air electrode layer 13 and the electrolyte layer. In particular, the barrier layer 15 may be GDC, and the thickness of each barrier layer 15 may be about 3 μm.

[0079] An embodiment of the present application provides a flat tube solid oxide electrolysis stack, in which the electrolyte layer 12 completely covers the support layer 11, and the air electrode layer 13 is not arranged in the edge area of ​​the electrolyte layer 12 near the fuel electrode cover plate 3, and the air electrode layer 13 is arranged in the area of ​​the electrolyte layer 12 except the edge area near the fuel electrode cover plate 3.

[0080] In the present application, the electrolyte layer 12 can completely cover the support layer 11. The air electrode layer 13 is not provided in the edge area of ​​the electrolyte layer 12 surface close to the fuel electrode cover plate 3, and the air electrode layer 13 is provided in the area of ​​the electrolyte layer 12 surface except the edge area close to the fuel electrode cover plate 3. Among them, not providing the air electrode layer 13 in the edge area of ​​the electrolyte layer 12 surface close to the fuel electrode cover plate 3 can prevent the air electrode layer 13 and the fuel electrode layer from being connected and short-circuited, that is, in the symmetrical flat tube solid oxide electrolytic cell 1, there is a certain distance between the fuel electrode and the air electrode. Figure 4-Figure 6 , Fig.12 As shown, the area of ​​the air electrode layer 13 is smaller than that of the support layer 11, and the air electrode layer 13 is not provided in the edge area of ​​the electrolyte layer 12 surface close to the fuel electrode cover plate 3 (i.e., the short side of the electrolyte layer 12 surface).

[0081] Among them, the preparation process of the symmetrical flat tube solid oxide electrolytic cell 1 can be: nickel oxide and 3YSZ slurry are mixed by extrusion molding, and calcined at 1100°C to obtain a battery blank (i.e., a support layer 11, and a fuel channel 10 is provided in the battery blank); an active fuel electrode layer NiO / 8YSZ (10μm~15μm), an electrolyte layer 8YSZ (10μm~15μm), a barrier layer GDC, and an air electrode layer LSCF-GDC (15μm~20μm) are obtained on both sides of the battery blank by screen printing, and they are sintered into shape respectively, and finally a symmetrical flat tube solid oxide electrolytic cell 1 with a structure from top to bottom of LSCF-GDC / GDC / 8YSZ / Ni-8YSZ / Ni-3YSZ / Ni-8YSZ / 8YSZ / GDC / LSCF-GDC is obtained. The size of the entire symmetrical flat tube solid oxide electrolytic cell 1 can be 155 mm × 63 mm × 2.7 mm (length × width × thickness), and the effective area is 120 cm 2 .

[0082] The above-mentioned symmetrical flat tube solid oxide electrolytic cell 1 has a relatively good short-time charging performance. Specifically, the electrolytic cell performance is described in the following examples.

[0083] Gas flow rate: fuel electrode: fuel electrode: 0.4L / min H2+H2O;

[0084] Among them, the H2 at the fuel electrode is used to play a protective role.

[0085] Test process: The performance of the electrolytic cell when the water bath temperature is 81°C, 86°C, 90°C, 94°C, and 97°C (the saturated vapor pressure of pure water is 50%, 60%, 70%, 80%, and 90%, respectively).

[0086] 1. Water bath temperature t = 81 ° C (pure water saturated vapor pressure is 50%), gas pipe heating temperature T = 120 ° C. OCV = 0.911 V [CC] = 43 A, E ≈ 1.36-1.44 V (large fluctuations, rapid decay)

[0087] [LCC charging] E = 1.300V, I = 43A

[0088] 2. Water bath temperature t = 86 ° C (pure water saturated vapor pressure is 60%), air pipe heating temperature T = 120 ° C.

[0089] OCV=0.908V[CC]=45A,E≈1.28-1.29V(Compared with t=81℃, the curve is obviously stable)

[0090] [LCC charging] E = 1.300V, I = 45A

[0091] 3. Water bath temperature t = 90 ° C (pure water saturated vapor pressure is 70%), air pipe heating temperature T = 120 ° C

[0092] OCV=0.901V[CC]=50A, E≈1.34V

[0093] [LCC charging] E = 1.300V, I = 47A

[0094] 4. Water bath temperature t = 94°C (the saturated vapor pressure of pure water is 80%), and air pipe heating temperature T = 120°C.

[0095] OCV=0.884V[CC]=54A, E≈1.27-1.29V

[0096] [LCC charging] E = 1.300V, I = 55A

[0097] 5. Water bath temperature t = 97°C (the saturated vapor pressure of pure water is 90%), and air pipe heating temperature T = 120°C.

[0098] OCV=0.867V[CC]=58A, E≈1.301V

[0099] [LCC charging] E = 1.300V, I = 58A

[0100] For details, please refer to Fig.13 , which shows the SOEC mode IV polarization curve at different water bath temperatures, where the abscissa is the current density in mA / cm 2 , the ordinate is voltage, the unit is V. From the above, it can be seen that with the increase of water vapor amount, the charging current density at the same voltage increases significantly, and the polarization curve becomes flat when the water bath temperature is above 94°C. However, during the short-term constant current charging process, the charging voltage has a clear and visible increase at each water vapor amount.

[0101] In addition, the symmetrical flat tube solid oxide electrolytic cell 1 provided in the present application also has good long-term stability during electrolysis. Specifically, the following embodiments are used to illustrate.

[0102] At a current density of 200 mA / cm 2 The durability of seawater electrolysis was studied for a long time, with the hydrogen carrier gas at 0.2 L / min and the hydrogen production rate at Fig.14 As shown, it is a curve diagram of voltage and hydrogen production under long-term constant current. The actual hydrogen production is about 180mL / min ( Fig.14 The hydrogen output is about 380mL / min, the hydrogen intake is 200mL / min, so the electrolytic hydrogen production is about 180mL / min), which is consistent with the theoretical value. And it shows good long-term stability. Fig.14In the figure, the horizontal axis is time in h, the vertical axis on the left is voltage in V, and the vertical axis on the right is output in mL / min.

[0103] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the term "include", "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or equipment that includes a series of elements are inherent to the elements. In the absence of more restrictions, the elements limited by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or equipment that includes the elements. In addition, the above-mentioned technical solution provided in the embodiment of the present application is consistent with the corresponding technical solution in the prior art in principle, and the part is not described in detail, so as not to repeat too much.

[0104] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A flat tube solid oxide electrolysis stack, characterized in that: include: Electrolytic stack; The electrolytic stack comprises a stacked symmetrical flat tube solid oxide electrolytic cell (1), wherein the symmetrical flat tube solid oxide electrolytic cell (1) comprises a support layer (11) with a fuel channel (10), an electrolyte layer (12) and an air electrode layer (13) symmetrically distributed on the upper and lower surfaces of the support layer (11), and a permeable conductive mesh (2) arranged on the surface of the air electrode layer (13) and connecting the air electrode layer (13) on both sides of the symmetrical flat tube solid oxide electrolytic cell (1); A fuel electrode cover plate (3) disposed at both ends of the electrolytic stack, connected to the support layer (11) and comprising an air cavity (31) sealed to the fuel channel (10); A gas delivery pipeline (4) connected to the gas cavity (31) of the fuel electrode cover plate (3); An air electrode cover plate (5) is arranged on the upper surface and the lower surface of the electrolytic cell stack and is fixedly connected thereto.

2. The flat tube solid oxide electrolysis stack according to claim 1, characterized in that: A groove (32) for accommodating the symmetrical flat tube type solid oxide electrolytic cell (1) is provided on a side of the fuel electrode cover plate (3) in contact with the electrolytic cell stack; An air hole (33) connected to the air cavity (31) and the fuel channel (10) is provided at the bottom of the groove (32).

3. The flat tube solid oxide electrolysis stack according to claim 2, characterized in that: A sealant is provided in the gap between the groove (32) and the symmetrical flat-tube solid oxide electrolytic cell (1).

4. The flat tube solid oxide electrolysis stack according to claim 1, characterized in that: A porous metal layer or a foam metal layer is provided between the fuel electrode cover plate (3) and the electrolytic cell stack.

5. The flat tube solid oxide electrolysis stack according to claim 4, characterized in that: A porous nickel layer or a foamed nickel layer is provided between the fuel electrode cover plate (3) and the electrolytic cell stack.

6. The flat tube solid oxide electrolysis stack according to claim 1, characterized in that: The air electrode cover plates (5) arranged on the upper surface and the lower surface of the electrolytic cell stack are fixedly connected by screws (6).

7. The flat tube solid oxide electrolysis stack according to claim 1, characterized in that: The air-permeable conductive mesh (2) is a silver mesh.

8. The flat tube solid oxide electrolysis stack according to any one of claims 1 to 7, characterized in that: The symmetrical flat tube solid oxide electrolytic cell (1) further comprises an active fuel electrode layer (14) symmetrically distributed on the upper and lower surfaces of the support layer (11) and located between the support layer (11) and the electrolyte layer (12).

9. The flat tube solid oxide electrolysis stack according to claim 8, characterized in that: The symmetrical flat-tube solid oxide electrolytic cell (1) further comprises a barrier layer (15) symmetrically distributed on the upper and lower surfaces of the support layer (11) and located between the electrolyte layer (12) and the air electrode layer (13).

10. The flat tube solid oxide electrolysis stack according to claim 8, characterized in that: The electrolyte layer (12) completely covers the support layer (11), the air electrode layer (13) is not provided in the edge area of ​​the surface of the electrolyte layer (12) close to the fuel electrode cover plate (3), and the air electrode layer (13) is provided in the area of ​​the surface of the electrolyte layer (12) other than the edge area close to the fuel electrode cover plate (3).

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