A self-sealing bamboo-shaped solid oxide fuel cell / electrolyzer and its stack

Abstract

This invention provides a self-sealing bamboo-joint tube-type solid oxide fuel cell / electrolyte and its stack, comprising a ceramic support, a porous insulating layer on its surface, and a battery pack. The battery pack consists of a first single cell and several other single cells connected in series along the fuel gas flow direction on the surface of the porous insulating layer. In the battery pack, a first insulating layer is disposed between adjacent fuel electrodes, a first connector and a second insulating layer are sequentially disposed between adjacent electrolyte layers along the fuel flow direction, and a third insulating layer is disposed between adjacent air electrodes. The insulating layers maintain the independent structure of the single cells, improve the sealing performance of the single cells, and prevent short circuits. The first connector is designed to longitudinally connect the fuel electrode and air electrode of adjacent battery cells, enabling current to be vertically transmitted from the fuel electrode of one battery cell to the air electrode of an adjacent battery cell through the connector. This allows for longitudinal current transmission between battery cells through the connector, reducing current loss during transmission and improving battery performance.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, and in particular to a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte and its cell / electrolyte stack. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are all-solid-state chemical power generation devices that efficiently and environmentally convert the chemical energy stored in fuel and oxidant into electrical energy directly at medium to high temperatures. They represent the most promising energy conversion and storage technology for the future. Tubular SOFCs are considered ideal prime movers for distributed energy systems due to their ease of assembly into high-power stacks and their ability to operate under pressure.

[0003] Traditional tubular SOFCs collect current circumferentially, resulting in significant ohmic losses and low power density per cell. The multi-section tubular SOFC developed to address this issue integrates multiple tubular SOFCs in series on a single support tube, while simultaneously altering the current flow direction within the cell, eliminating circumferential current flow. This is expected to significantly reduce ohmic losses and substantially increase the output power per cell.

[0004] However, the improved multi-section tubular SOFC still has the problem of long current transmission path in the connector (current is conducted laterally in the connector), insufficient sealing between multiple battery cells, which leads to oxidation of the fuel electrode, and short circuits caused by this, resulting in leakage and other problems, which limit the further improvement of battery performance. Summary of the Invention

[0005] To address the technical problems existing in the aforementioned related technologies, this application provides a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte and its battery / electrolyte stack. By adding a structure to maintain the independence of the battery cell in the single cell structure, the sealing performance of the single cell is improved, and short circuits are avoided. By connecting the connector between the fuel electrode and the air electrode, the current is longitudinally transmitted in the connector, effectively improving the performance of the battery / electrolyte.

[0006] The details are as follows:

[0007] In a first aspect, the present invention provides a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte, comprising a ceramic support with one end open and the other end closed, a porous insulating layer distributed on the surface of the ceramic support, and a battery pack distributed on the surface of the porous insulating layer, wherein the battery pack consists of a first single cell and several other single cells connected in series along the fuel gas flow direction on the surface of the porous insulating layer.

[0008] In the battery pack, a first insulating layer is provided between the fuel electrodes of every two adjacent single cells, a first connector and a second insulating layer are provided sequentially between the electrolyte layers of every two adjacent single cells along the fuel gas flow direction, and a third insulating layer is provided between the air electrodes of every two adjacent single cells.

[0009] Each of the first connectors covers the first insulating layer located beneath it and partially overlaps the fuel electrode located beneath it;

[0010] The third insulating layer is vertically disposed directly above the second insulating layer.

[0011] Optionally, in the first single cell, the fuel electrode, the electrolyte layer, and the air electrode are arranged in a stepped-back configuration based on the porous insulating layer.

[0012] Optionally, the fuel electrode is arranged with a 1-5 mm recess based on the porous insulating layer;

[0013] The electrolyte layer is laid out based on the fuel electrode recess of 0.4-2 mm;

[0014] The air electrode is arranged with a 0.4-2 mm back slope based on the electrolyte layer.

[0015] Optionally, an electrolyte tip is provided between the fuel electrodes of two adjacent single cells, and each electrolyte tip is located on the side near the opening end of the ceramic support.

[0016] Optionally, each of the electrolyte terminals is partially or completely covered by the electrolyte layer located above it.

[0017] Optionally, the overlap length between each of the first connectors and the fuel electrode located below it is 0.2-2 mm.

[0018] Optionally, the closed end of the ceramic support is provided with an electrolyte coating layer; a second connector is provided between the electrolyte coating layer and the last single cell near the closed end;

[0019] The second connector is in contact with the ceramic support and is covered by the air electrode of the last single cell;

[0020] An electrolyte terminal is provided between the fuel electrode and the second connector in the last single cell.

[0021] Optionally, the first insulating layer is at the same height as the fuel electrode;

[0022] The first connector and the second insulating layer are at the same height as the electrolyte layer;

[0023] The third insulating layer is at the same height as the air electrode.

[0024] Optionally, the thickness of the porous insulating layer is 100 μm-300 μm;

[0025] The thickness of the fuel electrode is 50 μm-250 μm;

[0026] The thickness of the electrolyte layer is 10μm-100μm;

[0027] The thickness of the air electrode is 500μm-1500μm.

[0028] In a second aspect, the present invention provides a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte stack, the solid oxide fuel cell / electrolyte stack comprising: two or more solid oxide fuel cell / electrolyte stack structures of the self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte structure described in the first aspect.

[0029] Compared with related technologies, the self-sealing bamboo-shaped solid oxide fuel cell / electrolyte and its stack provided by the present invention have at least the following advantages:

[0030] The self-sealing bamboo-joint tube solid oxide fuel cell / electrolyte provided by the present invention uses a ceramic circular tube with one end open and the other end closed as a support structure. The series battery pack is distributed on the surface of the circular tube. Insulation layers are provided between the battery pack and the support, as well as between the functional layers of each battery unit in the battery pack, to maintain the independent structure of the battery units, improve the sealing of the single battery unit, and avoid short circuits or leakage current in the battery / electrolyte.

[0031] In the bamboo-shaped solid oxide fuel cell / electrolyte provided by the present invention, the first connector is disposed on the same plane as the electrolyte layer and longitudinally overlaps the fuel electrode and air electrode of the adjacent battery cell. This enables the current to be vertically transmitted from the fuel electrode of one battery cell to the air electrode of the adjacent battery cell through the connector, thereby enabling the current between battery cells to be transmitted longitudinally through the connector, reducing the loss of current during transmission and improving the performance of the battery / electrolyte.

[0032] The self-sealing bamboo-joint tube-type solid oxide fuel cell / electrolyzer provided by this invention has a dense electrolyte layer covering the sealed end, which has self-sealing characteristics and solves the problem of sealing difficulties under high temperature operation. Furthermore, for the inert ceramic support, the second connector can seal the porous insulating layer to prevent the fuel electrode from being oxidized. For the support that can be reduced to metal ceramic by hydrogen in the working state, the current collected by the battery pack can also be introduced into the conductive ceramic support through the second connector connected to the support, thus solving the current collection problem of multi-joint tube-type solid oxide fuel cells / electrolyzers.

[0033] The self-sealing bamboo-joint tube-type solid oxide fuel cell / electrolyte provided by this invention uses screen printing to prepare each functional layer of the battery unit, which can improve the film formation speed, effectively improve the preparation efficiency, simplify the preparation method, save the preparation cost, and facilitate the commercialization of solid oxide fuel cells. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the structure of the self-sealing bamboo-shaped solid oxide fuel cell / electrolyte provided in an embodiment of the present invention is shown. Detailed Implementation

[0036] The following embodiments are provided to better understand the present invention and are not limited to the preferred embodiments described. They do not constitute a limitation on the content and scope of protection of the present invention. Any product that is the same as or similar to the present invention, derived by any person under the guidance of the present invention or by combining the features of the present invention with other prior art, falls within the protection scope of the present invention.

[0037] Specific experimental steps or conditions are not specified in the examples; however, they can be performed according to the conventional experimental steps or conditions described in the prior art. Reagents and other instruments used, unless otherwise specified, are all commercially available conventional reagent products.

[0038] Since solid oxide fuel cells and solid oxide electrolyzers are a pair of energy conversion devices with the same structure but opposite working processes, the structure of this invention is also applicable to a solid oxide electrolyzer structure.

[0039] In a first aspect, the present invention provides a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte. Figure 1 A partial cross-sectional schematic diagram of the self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte provided in an embodiment of the present invention is shown, as follows: Figure 1As shown, the bamboo-shaped solid oxide fuel cell / electrolyte includes a ceramic support 1 with one end open and the other end closed, a porous insulating layer 2 distributed on the surface of the ceramic support, and a battery pack distributed on the surface of the porous insulating layer with a thickness of 100μm-300μm. Specifically, the battery pack consists of a first single cell and several other single cells connected in series along the fuel gas flow direction on the surface of the porous insulating layer. Each single cell specifically consists of a fuel electrode, an electrolyte layer, and an air electrode. In the battery pack, a first insulating layer 4 is provided between the fuel electrodes of every two adjacent single cells. The 4th layer is at the same height as the fuel electrode 3; between each pair of adjacent single cells, the electrolyte layer 6 is provided with a first connector 7 and a second insulating layer 8 in sequence along the fuel gas flow direction, the first connector 7 and the second insulating layer 8 are at the same height as the electrolyte layer 6; between each pair of adjacent single cells, the air electrode 9 is provided with a third insulating layer 10, the third insulating layer 10 is at the same height as the air electrode 9; each first connector 7 covers the first insulating layer 4 located below it and partially overlaps the fuel electrode of the adjacent single cell located below it; the third insulating layer 10 is vertically arranged directly above the second insulating layer 8.

[0040] It should be noted that in the first single cell, i.e., the first single cell unit closest to the opening end of the ceramic support, the functional layers (fuel electrode 3, electrolyte layer 6, and air electrode 9) are arranged in a stepped-back configuration based on the porous insulating layer 2. Specifically, the fuel electrode 3 is stepped back 1-5 mm from the porous insulating layer 2; the electrolyte layer 6 is stepped back 0.4-2 mm from the fuel electrode 3; and the air electrode 9 is stepped back 0.4-2 mm from the electrolyte layer 6. Other single cells connected in series with it exhibit the same layout orientation due to the stepped-back arrangement of their functional layers.

[0041] In practical implementation, due to the staggered arrangement of each functional layer, it can be understood that there is a gap between the functional layers of two adjacent single-cell units. For example, there are gaps between the fuel electrodes 3 of two adjacent single-cell units, between the electrolyte layers 6 of two adjacent single-cell units, and between the air electrodes 9 of two adjacent single-cell units. In this embodiment of the invention, a first insulating layer 4 is provided at the gap between the fuel electrodes 3 of each adjacent single-cell unit to block the passage between the fuel electrodes 3. In this embodiment of the invention, a second insulating layer 8 is provided at the gap between the electrolyte layers 6 of each adjacent single-cell unit to block the passage between the electrolyte layers 6. In this embodiment of the invention, a third insulating layer 10 is provided at the gap between the air electrodes 9 of each adjacent single-cell unit to block the passage between the air electrodes 9. The provision of the first insulating layer 4, the second insulating layer 8, and the third insulating layer 10 achieves the sealing of the battery unit and the independence between the battery units, avoiding problems such as short circuit leakage current caused by the close proximity of the battery units. It should be noted that the first insulating layer 4, the second insulating layer 8, and the third insulating layer 10 are made of the same insulating layer material, and the first insulating layer 4, the second insulating layer 8, and the third insulating layer 10 are all dense structures.

[0042] Furthermore, in this embodiment of the invention, a first connector 7 is provided at the interval between the electrolyte layers 6 of each two adjacent single-cell units. That is, a first connector 7 and a second insulating layer 8 are simultaneously provided at the interval between the electrolyte layers 6 of each two adjacent single-cell units, and the first connector 7 and the second insulating layer 8 are sequentially arranged at the interval along the fuel gas flow direction. Based on the stepped arrangement of the functional layers, the position of each first connector 7 can cover the first insulating layer 4 located below it and partially overlap the fuel electrode of the adjacent single cell located below it. Since the electrolyte layer 6 and the first connector 7 are arranged on the same plane and longitudinally overlap the fuel electrode and air electrode of the adjacent battery unit, it not only facilitates the realization of the connector preparation process, but also changes the current collection method between battery units in the existing solid oxide fuel cell. This allows the current to be vertically transmitted from the fuel electrode of one battery unit to the air electrode of the adjacent battery unit it overlaps with through the first connector 7, so that the current between battery units can be transmitted longitudinally through the connector, reducing the loss of current in the transmission process and improving the performance of the battery / electrolyte.

[0043] As an example, the overlap length between each first connector 7 and the fuel electrode located below it is 0.2-2 mm.

[0044] In some embodiments, an electrolyte tip 5 is further provided at the interval between each pair of adjacent fuel electrodes 3 of a single cell. The electrolyte tip is made of the same material as the electrolyte layer 6. See also Figure 1As shown, an electrolyte tip 5 and a first insulating layer 4 are simultaneously provided at the interval between the fuel electrodes 3 of each adjacent single cell unit. The electrolyte tip 5 and the first insulating layer are sequentially arranged at the interval along the fuel gas flow direction (each electrolyte tip 5 is located on the side near the opening end of the ceramic support). Each electrolyte tip 5 is covered or partially covered by an electrolyte layer 6, so that there is no connection interface between each first insulating layer 4 and the electrolyte layer 6. Since the electrolyte tip 5 and the electrolyte layer 6 have the same material composition and the same coefficient of thermal expansion, their contact surface has the same shrinkage behavior during subsequent sintering or battery operation. This arrangement avoids the problem of the first insulating layer 4 being only provided between the fuel electrodes. Due to the different materials of the first insulating layer 4 and the electrolyte layer 6 above it, there is a difference in the coefficient of thermal expansion. This would cause a mismatch in shrinkage between the first insulating layer and the electrolyte layer above it during subsequent sintering or battery operation, resulting in microcracks in the electrolyte layer, which would affect the performance and service life of the battery / electrolyte.

[0045] In specific implementation, the self-sealing bamboo-joint tube-type solid oxide fuel cell / electrolyte provided in this embodiment of the invention is provided with an electrolyte coating layer 11 at the closed end; this solves the high-temperature sealing problem of multi-joint tube-type solid oxide fuel cells; a second connector 12 is provided between the electrolyte coating layer 11 and the last single cell near the closed end; it should be noted that the last single cell is the first single cell unit closest to the closed end of the ceramic support, or the single cell unit farthest from the first single cell; it should also be noted that in this embodiment of the invention, the ceramic support can be composed of inert components. The ceramic (which, under operating conditions, will not be reduced to a metallic ceramic by hydrogen) can also be a ceramic composition that can be reduced to a metallic ceramic by hydrogen under operating conditions; the second connector 12 is in contact with the ceramic support 1 and is covered by the air electrode 9 of the last single cell; thus, for a ceramic support composed of inert components, the second connector 12 can seal the porous insulating layer to prevent the fuel electrode from being oxidized; for a support that can be reduced to a metallic ceramic by hydrogen under operating conditions, the second connector can guide the current collected in the last single cell into the ceramic support, solving the current collection problem.

[0046] In some embodiments, an electrolyte terminal 5 is provided between the fuel electrode 3 and the second connector 12 in the last single cell to prevent the fuel electrode 3 of the last single cell from being connected to the second connector 12.

[0047] It should be noted that in the self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte provided by the present invention, each functional layer of the battery unit and the structure that keeps the battery unit independent can be prepared by screen printing, which can improve the film formation speed, effectively improve the preparation efficiency, simplify the preparation method, save the preparation cost, and facilitate the commercialization of solid oxide fuel cells.

[0048] In a second aspect, the present invention provides a self-sealing bamboo-tube type solid oxide fuel cell stack, the solid oxide fuel cell / electrolyte stack comprising: two or more solid oxide fuel cell / electrolyte stack structures of the self-sealing bamboo-tube type solid oxide fuel cell / electrolyte structure described in the first aspect.

[0049] To enable those skilled in the art to better understand the present invention, the following describes a self-sealing bamboo-shaped solid oxide fuel cell / electrolyte and its battery / electrolyte stack provided by the present invention through several specific embodiments.

[0050] Example 1

[0051] Step 1: A hollow cylindrical ceramic tube with an open end and a closed end is used as the base tube. This closed-section structure achieves self-sealing of the battery. The base tube is composed of 3 mol calcium oxide-stabilized zirconium oxide (3CSZ) and nickel oxide (NiO) in a mass ratio of 55:45. NiO can be reduced to Ni by hydrogen in the working state and has electrical conductivity. Its outer diameter is 15-25 mm, its wall thickness is 1.5-3 mm, and its porosity is 25%-35%. Further, a first insulating layer paste is printed on the surface of the base tube by screen printing. The insulating layer paste is composed of strontium zirconate (SrZrO3) and 2 mol% aluminum oxide (Al2O3), with a thickness of 100 μm. After screen printing, it is dried at 60 °C to prepare a porous insulating film layer.

[0052] Step 2: The fuel electrode slurry is printed at intervals on the porous insulating film layer using screen printing to form a fuel electrode film layer, and the fuel electrodes are arranged with a 5 mm backing from the porous insulating layer. The fuel electrode slurry is composed of 8 mol yttrium-stabilized zirconium oxide (8YSZ) and nickel oxide (NiO) in a mass ratio of 60:40, with a thickness of 50 μm, a width of 5 mm for each fuel electrode unit, and a 2 mm spacing between adjacent fuel electrodes. After screen printing, the mixture is dried at 60 °C.

[0053] Step 3: Between the above fuel electrode film layers, along the fuel gas flow direction, an electrolyte slurry and a second insulating layer slurry are printed respectively; the electrolyte slurry is composed of 8 mol of yttrium-stabilized zirconium oxide (8YSZ), with a printing thickness of 50 μm and a width of 1 mm, forming the first electrolyte end film layer, and the electrolyte end film layer is located on the side close to the opening end of the ceramic support; the insulating layer slurry is composed of strontium zirconate (SrZrO3) and 6 mol% aluminum oxide (Al2O3), with a screen printing thickness of 50 μm and a width of 1 mm, forming the first insulating film layer.

[0054] Step 4: Above the end region of the first insulating film layer near the closed end, at the same height as the fuel electrode, print electrolyte slurry; the electrolyte slurry has the same composition as the first electrolyte end film layer, both being 8 mol yttrium oxide stabilized zirconium oxide (8YSZ), with a printing thickness of 50 μm and a width of 1 mm. After screen printing, dry at 60 °C to obtain the second electrolyte end film layer.

[0055] Step 5: Print electrolyte slurry at intervals above the fuel electrode. The electrolyte layer is laid with a 1 mm backing from the fuel electrode, so that it partially covers the fuel electrode film layer below it, and partially or completely covers the first electrolyte end film layer below it. The electrolyte slurry has the same composition as the first and second electrolyte end film layers, which are 8 mol yttrium oxide stabilized zirconium oxide (8YSZ). The printing thickness is 20 μm and the width is 4 mm. After screen printing, it is dried at 60 °C to obtain the electrolyte film layer.

[0056] Step 6: At the intervals between the electrolyte membrane layers, print the connector paste and the second insulating layer paste along the fuel gas flow direction, respectively; wherein the connector paste is composed of lanthanum strontium titanate (La). 0.3 Sr 0.7 TiO3 (LST) is printed with a thickness of 20 μm and a width of 2 mm. The connector is located on the same plane as the electrolyte layer and overlaps with the fuel electrode below it by 1 mm, covering the first insulating film layer below it. The insulating layer slurry is composed of strontium zirconate (SrZrO3) and 6 mol% alumina (Al2O3), with a printing thickness of 20 μm and a width of 1 mm. After screen printing, it is dried at 60 °C.

[0057] Step 7: On the side of the first insulating film layer near the sealed end, print the connector paste so that the connector comes into contact with the ceramic support; the connector paste is composed of lanthanum-doped strontium titanate (La). 0.3 Sr 0.7 TiO3 (LST) was printed with a thickness of 170 μm and a width of 2 mm to obtain the second interconnect film.

[0058] Step 8: Continue printing the second insulating layer paste on top of the second insulating film layer to form the third insulating film layer. The insulating layer paste is composed of strontium zirconate (SrZrO3) and 6 mol% aluminum oxide (Al2O3). The printing thickness is 500 μm and the width is 1 mm. After screen printing, dry at 40-80 ℃ to obtain the third insulating film layer, and the insulating film layer is at the same height as the air.

[0059] Step 9: Impregnate the sealed end with a 3 mol% zirconium oxychloride solution, and after drying, form an electrolyte coating layer to achieve the sealing treatment of the ceramic support tube sealed section.

[0060] Step 10: Heat the above-mentioned battery / electrolyte precursor to 400°C at a heating rate of 1°C / min and remove the binder in air for 6 hours. Then, heat the precursor from 400°C to 600°C at a heating rate of 1°C / min for 8 hours and remove the binder. Finally, sinter the precursor in air at 1400°C for 6 hours at a heating rate of 2°C / min.

[0061] Step 11: At the intervals of the third insulating film layer and above the connector, and at a position 2 mm below the electrolyte layer of the first battery cell, print an air electrode paste; the air electrode paste is composed of 8 mol of yttrium-stabilized zirconium oxide (8YSZ) and strontium-doped lanthanum manganate (La) in a mass ratio of 50:50. 0.8 Sr 0.2 MnO3 (LSM) was printed with a thickness of 500 μm and a width of 6 mm. After screen printing, it was dried at 40 °C to obtain an air electrode film layer. This air electrode film layer was longitudinally connected to the fuel electrode of the adjacent battery cell through the connector below it, and was in contact with the ceramic support through the second connector.

[0062] Step 12: The above-mentioned battery / electrolyte precursor is sintered in air at 1200 °C for 4 h with a heating rate of 2 °C / min to obtain a tubular solid oxide fuel cell / electrolyte.

[0063] Example 2

[0064] Step 1: A hollow cylindrical ceramic tube with an open end and a closed end is used as the base tube. This closed-section structure achieves self-sealing of the battery. The base tube is composed of 3 mol calcium oxide-stabilized zirconium oxide (3CSZ), with an outer diameter of 15-25 mm, a wall thickness of 1.5-3 mm, and a porosity of 25%-35%. Further, a first insulating layer paste is printed on the surface of the base tube using screen printing. This insulating layer paste is composed of magnesium aluminum spinel (MgAl2O4) and 30 mol% magnesium oxide (MgO), with a thickness of 50 μm. After screen printing, it is dried at 50°C to prepare a porous insulating layer.

[0065] Step 2: The fuel electrode paste is printed at intervals on the porous insulating film layer using screen printing to form a fuel electrode film layer, and the fuel electrodes are arranged with a 2 mm backing from the porous insulating layer. The fuel electrode paste is composed of 8 mol yttrium-stabilized zirconium oxide (8YSZ) and nickel oxide (NiO) in a mass ratio of 60:40, with a thickness of 50 μm, a width of 4 mm for each fuel electrode unit, and a 1 mm spacing between adjacent fuel electrodes. After screen printing, the paste is dried at 50°C.

[0066] Step 3: Between the above fuel electrode film layers, along the fuel gas flow direction, an electrolyte slurry and a second insulating layer slurry are printed respectively. The electrolyte slurry consists of 8 mol of yttrium-stabilized zirconium oxide (8YSZ), with a printing thickness of 50 μm and a width of 0.5 mm, forming the first electrolyte end film layer. The electrolyte end film layer is located on the side close to the opening end of the ceramic support. The insulating layer slurry consists of magnesium aluminum spinel (MgAl2O4), 30 mol% magnesium oxide (MgO), and 10 mol% zirconium oxide (ZrO2), with a screen printing thickness of 50 μm and a width of 0.5 mm, forming the first insulating film layer.

[0067] Step 4: Above the end region of the first insulating film layer near the closed end, at the same height as the fuel electrode, print the electrolyte slurry. The electrolyte slurry has the same composition as the first electrolyte end film layer, which is 8 mol of yttrium oxide-stabilized zirconium oxide (8YSZ). The printing thickness is 50 μm and the width is 0.5 mm. After screen printing, dry at 50 °C to obtain the second electrolyte end film layer.

[0068] Step 5: Print electrolyte slurry at intervals above the fuel electrode. The electrolyte layer is laid with a 0.5 mm backing from the fuel electrode, so that it partially covers the fuel electrode film layer below it, and partially or completely covers the first electrolyte end film layer below it. The electrolyte slurry has the same composition as the first and second electrolyte end film layers, which are 8 mol yttrium oxide stabilized zirconium oxide (8YSZ). The printing thickness is 20 μm and the width is 3.5 mm. After screen printing, it is dried at 50°C to obtain the electrolyte film layer.

[0069] Step 6: At the intervals between the electrolyte membrane layers, print the connector paste and the second insulating layer paste along the fuel gas flow direction, respectively; wherein the connector paste is composed of lanthanum strontium titanate (La). 0.3 Sr 0.7TiO3 (LST) is printed with a thickness of 20 μm and a width of 1 mm. The connector is located on the same plane as the electrolyte layer and overlaps with the fuel electrode below it by 0.5 mm, covering the first insulating film layer below it. The insulating layer slurry is composed of magnesium aluminum spinel (MgAl2O4), 30 mol% magnesium oxide (MgO) and 10 mol% zirconium oxide (ZrO2), with a printing thickness of 20 μm and a width of 0.5 mm. After screen printing, it is dried at 50°C.

[0070] Step 7: On the side of the first insulating film layer near the sealed end, print the connector paste so that the connector comes into contact with the ceramic support; the connector paste is composed of lanthanum-doped strontium titanate (La). 0.3 Sr 0.7 TiO3 (LST) was printed with a thickness of 170 μm and a width of 1.5 mm to obtain the second connector film.

[0071] Step 8: Continue printing the second insulating layer paste on top of the second insulating film layer to form the third insulating film layer. The composition of the insulating layer paste is magnesium aluminum spinel (MgAl2O4), 30 mol% magnesium oxide (MgO) and 10 mol% zirconium oxide (ZrO2). The printing thickness is 500 μm and the width is 1 mm. After screen printing, dry at 50 °C to obtain the third insulating film layer, and the insulating film layer is at the same height as the air.

[0072] Step 9: Impregnate the sealed end with a 3 mol% zirconium oxychloride solution, and after drying, form an electrolyte coating layer to achieve the sealing treatment of the ceramic support tube sealed section.

[0073] Step 10: Heat the above-mentioned battery / electrolyte precursor to 400°C at a heating rate of 1°C / min and remove the binder in air for 6 hours. Then, heat the precursor from 400°C to 600°C at a heating rate of 1°C / min for 8 hours and remove the binder. Finally, sinter the precursor in air at 1400°C for 6 hours at a heating rate of 2°C / min.

[0074] Step 11: At the intervals of the third insulating film layer and above the connector, and at a position 1 mm below the electrolyte layer of the first battery cell, print an air electrode paste; the air electrode paste is composed of 8 mol yttrium-stabilized zirconium oxide (8YSZ) and strontium-doped lanthanum manganate (La) in a mass ratio of 50:50. 0.8 Sr 0.2MnO3 (LSM) was printed with a thickness of 500 μm and a width of 4.5 mm. After screen printing, it was dried at 50°C to obtain an air electrode film layer. This air electrode film layer was longitudinally connected to the fuel electrode of the adjacent battery cell through the connector below it, and was in contact with the ceramic support through the second connector.

[0075] Step 12: The above-mentioned battery / electrolyte precursor is sintered in air at 1200 °C for 4 h with a heating rate of 2 °C / min to obtain a tubular solid oxide fuel cell / electrolyte.

[0076] Example 3:

[0077] This embodiment uses a hollow cylindrical ceramic tube with an open end and a closed end as the base tube. The base tube is composed of 3 mol of yttrium oxide-stabilized zirconium oxide (3YSZ) and nickel oxide (NiO) in a mass ratio of 50:50. The remaining steps are the same as in Example 1.

[0078] Example 4: This example uses a hollow cylindrical ceramic tube with an open end and a closed end as the base tube. The base tube is composed of magnesium aluminum spinel (MgAl2O4) and 30 mol% magnesium oxide (MgO). The remaining steps are the same as in Example 2.

[0079] The foregoing has provided a detailed description of a self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyte and its battery / electrolyte stack provided by the present invention. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyzer, characterized in that, It includes a ceramic support with one end open and the other end closed, a porous insulating layer distributed on the surface of the ceramic support, and a battery pack distributed on the surface of the porous insulating layer. The battery pack consists of a first single cell and several other single cells connected in series along the direction of fuel gas flow on the surface of the porous insulating layer. In the battery pack, a first insulating layer is provided between the fuel electrodes of every two adjacent single cells, a first connector and a second insulating layer are provided sequentially between the electrolyte layers of every two adjacent single cells along the fuel gas flow direction, and a third insulating layer is provided between the air electrodes of every two adjacent single cells. Each of the first connectors covers the first insulating layer located beneath it and partially overlaps the fuel electrode located beneath it; The third insulating layer is vertically disposed directly above the second insulating layer; An electrolyte tip is provided between the fuel electrodes of two adjacent single cells, and each electrolyte tip is located on the side near the opening end of the ceramic support; each electrolyte tip is partially or completely covered by the electrolyte layer located above it; the electrolyte tip is made of the same material as the electrolyte layer. The overlap length between each of the first connectors and the fuel electrode located below it is 0.2-2 mm; the first connectors are composed of lanthanum-doped strontium titanate (La). 0.3 Sr 0.7 TiO3; the first connector and the second insulating layer are at the same height as the electrolyte layer; An electrolyte coating layer is provided at the closed end of the ceramic support; a second connector is provided between the electrolyte coating layer and the last single cell near the closed end; The second connector is in contact with the ceramic support and is covered by the air electrode of the last single cell; The first insulating layer is at the same height as the fuel electrode; The third insulating layer is at the same height as the air electrode.

2. The self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyzer according to claim 1, characterized in that, In the first single cell, the fuel electrode, the electrolyte layer, and the air electrode are arranged in a stepped-back configuration based on the porous insulating layer.

3. The self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyzer according to claim 2, characterized in that, The fuel electrode is arranged with a 1-5 mm backing off the porous insulating layer. The electrolyte layer is laid out based on the fuel electrode recess of 0.4-2 mm; The air electrode is arranged with a 0.4-2 mm back slope based on the electrolyte layer.

4. The self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyzer according to claim 1, characterized in that, An electrolyte terminal is provided between the fuel electrode and the second connector in the last single cell.

5. The self-sealing bamboo-joint tube type solid oxide fuel cell / electrolyzer according to claim 1, characterized in that, The thickness of the porous insulating layer is 100μm-300μm; The thickness of the fuel electrode is 50μm-250μm; The thickness of the electrolyte layer is 10μm-100μm; The thickness of the air electrode is 500μm-1500μm.

6. A self-sealing bamboo-joint tube type solid oxide fuel cell stack / electrolyte stack, characterized in that, The solid oxide fuel cell stack / electrolyte stack includes: two or more self-sealing bamboo-tube type solid oxide fuel cells / electrolytes as described in any one of claims 1-5.

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