A flat tube SOFC anode support and its preparation method as well as a flat tube solid oxide fuel cell and a stack

Abstract

The present invention belongs to the field of solid oxide fuel cells, and specifically relates to a flat tube SOFC anode support, a preparation method thereof, a flat tube solid oxide fuel cell, and a stack. The method comprises the following steps: preparing an anode layer membrane and a volatile layer membrane; processing the anode layer membrane into an anode upper layer, an anode middle layer, and an anode lower layer; machining a through hole in the anode middle layer; cutting the volatile layer membrane into volatile layer membrane strips; aligning and stacking the anode upper layer, the anode middle layer, and the anode lower layer to form a laminated body; performing warm isostatic pressing on the laminated body, and then sintering. The flat tube SOFC anode support prepared by the present invention using a cast membrane lamination method has the characteristics of thin thickness and high strength, and the pore size and proportion can be adjusted. The total thickness of a single cell containing the flat tube SOFC anode support can be controlled within 1 mm, which is beneficial for adjusting the fuel gas diffusion efficiency and increasing the number of single cells assembled per unit volume during stack assembly, thereby improving energy density.

Description

Technical Field

[0001] The present invention belongs to the field of solid oxide fuel cells, and in particular relates to a flat tube type SOFC anode support and a preparation method thereof, as well as a flat tube type solid oxide fuel cell and a stack. Background Art

[0002] Solid Oxide Fuel Cell (SOFC) belongs to the third generation of solid fuel cells. It is an all-solid-state chemical power generation device that converts the chemical energy stored in the fuel directly into electrical energy in an efficient and environmentally friendly manner at medium and high temperatures. It has broad application prospects. Currently, solid oxide fuel cells are mainly divided into tubular and flat plate types. The flat plate type includes thin plate type and flat tube type. The flat tube type is a solid oxide fuel cell with a symmetrical electrode layer structure. Its anode support contains a hollow tubular cavity for the circulation and diffusion of fuel gas. The cell structure is designed to be distributed up and down with the supporting electrode layer as the center. The supporting electrode layer has a hollow hole structure with two open ends to facilitate the passage of gas into the hollow hole from the side around the supporting electrode layer. The symmetrical structure of the cell is not only conducive to maintaining the flatness of the cell during the cell sintering process, but also can effectively offset the thermal stress generated during cell operation, thereby significantly reducing thermal stress and reducing damage to the electrolyte and electrodes. It has good application prospects.

[0003] CN114204044A discloses a method for preparing a supporting anode in an anode-supported solid oxide fuel cell with a symmetrical structure, and proposes to use an extrusion pressing method, an injection method, a grouting method or a 3D printing method to prepare a flat-plate solid oxide fuel cell with a symmetrical structure. However, when preparing a support body with a hollow channel structure, the existing preparation methods have disadvantages such as a large overall thickness of the single cell, a thick inner wall of the anode, a thickness of at least 2 mm for the prepared single cell, and high requirements for the mold, resulting in high preparation costs and increased difficulty in commercialization. Therefore, how to prepare the flat-plate solid oxide fuel cell with a symmetrical structure at low cost and high efficiency is one of the research topics of technical personnel in this field. Summary of the Invention

[0004] In order to solve the above problems, the present invention provides a flat tube SOFC anode support and its preparation method, as well as a flat tube solid oxide fuel cell and a stack. The method has the advantages of simple preparation method, low production cost, and mass production, and the obtained solid oxide fuel cell is thin in thickness and high in strength.

[0005] To achieve the above object, the present invention provides a method for preparing a flat tube SOFC anode support, comprising the following steps:

[0006] S1, preparing an anode layer membrane and a volatile layer membrane;

[0007] S2, processing the anode layer membrane into an anode upper layer, an anode middle layer and an anode lower layer;

[0008] S3, processing a plurality of rectangular through holes on the anode intermediate layer;

[0009] S4, cutting the volatile layer film sheet into volatile layer film strips, wherein the size of the volatile layer film strips matches the size of the rectangular through-hole and can be placed in the rectangular through-hole;

[0010] S5, aligning and stacking the anode upper layer, the anode middle layer, and the anode lower layer to form a laminated body, wherein the volatile layer film strips are placed in the rectangular through holes of the anode middle layer;

[0011] S6. Warm isostatically pressing the laminated green body, then cutting off both ends to expose both ends of the through hole to obtain a flat tube SOFC anode support green body, and then sintering the flat tube SOFC anode support to obtain a flat tube SOFC anode support.

[0012] A second object of the present invention is to provide a flat tube SOFC anode support prepared according to the aforementioned method.

[0013] A third object of the present invention is to provide a flat tube solid oxide fuel cell, wherein the flat tube SOFC comprises, from the inside to the outside, a flat tube SOFC anode support, an anode functional layer, an electrolyte layer and a cathode layer, and the flat tube SOFC anode support is the aforementioned flat tube SOFC anode support.

[0014] A fourth object of the present invention is to provide a fuel cell stack, comprising the aforementioned flat tube anode supported solid oxide fuel cell assembly.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. The flat-tube SOFC anode support prepared by the cast sheet lamination method is thin and high in strength. The total thickness of the single cell including the support can be controlled within 1 mm. The volume proportion of the gas flow channel is high, which is conducive to improving the fuel gas diffusion efficiency and stacking density.

[0017] 2. The cast film lamination method used in this process is a mature process that is mature and reliable in the MLCC, electronic ceramics and other industries and has the ability to be mass-produced.

[0018] 3. The anode layer membrane of the present invention is made primarily from a 3YSZ-NiO composite powder. Taking advantage of the fact that NiO and 3YSZ do not react with each other, the present invention uniformly mixes the 3YSZ powder with an insoluble nickel source and then anneals it. This physical barrier prevents the agglomeration and growth of NiO generated by the decomposition of 3YSZ and the insoluble nickel source during the thermal process, allowing the resulting YSZ and NiO to mix uniformly in primary particle size. The anode layer prepared from this 3YSZ-NiO composite powder exhibits excellent mechanical properties and good electronic conductivity, meeting diverse application requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 Schematic diagram of the preparation of a flat tube SOFC anode support body by tape casting lamination method;

[0020] Figure 2 2 is a schematic cross-sectional view of a flat tube SOFC anode support body in the present invention;

[0021] Figure 3 3YSZ-NiO composite powder preparation process according to one embodiment of the present invention;

[0022] Figure 4 It is a schematic cross-sectional view of the flat tube solid oxide fuel cell in the present invention.

[0023] Explanation of the accompanying symbols: 1-flat tube SOFC anode support 1; 2-anode functional layer; 3-electrolyte layer; 4-barrier layer; 5-cathode layer; 6-sealing layer; 10-flat tube SOFC anode support blank; 11-anode upper layer; 12-anode middle layer; 13-anode lower layer; 121-volatile layer membrane strip; 14, gas flow channel. DETAILED DESCRIPTION

[0024] The present invention will be described in detail below with reference to specific embodiments.

[0025] The Chinese meanings of the English abbreviations in this application document are as follows:

[0026] SOFC is a solid oxide fuel cell, NiO is nickel oxide, 3YSZ is 3 mol% yttrium-stabilized zirconia, 8YSZ is 8 mol% yttrium-stabilized zirconia, PMMA is polymethyl methacrylate, PVA is polyvinyl alcohol, PVB is polyvinyl butyral, DBP is dibutyl phthalate, PEG is polyethylene glycol, GDC is gadolinium oxide-doped cerium oxide, and LSCF is lanthanum strontium cobalt iron powder.

[0027] Figure 1 Schematic diagram of the preparation of a flat tube SOFC anode support body by tape casting lamination method, as shown in Figure 1As shown, the present invention provides a method for preparing a flat tube SOFC anode support, comprising the following steps:

[0028] S1, preparing an anode layer membrane and a volatile layer membrane;

[0029] S2, processing the anode layer membrane into an anode upper layer, an anode middle layer and an anode lower layer, wherein the three layers have the same external dimensions;

[0030] S3, processing a plurality of rectangular through holes on the anode intermediate layer;

[0031] S4, cutting the volatile layer film sheet into volatile layer film strips, wherein the size of the volatile layer film strips matches the size of the rectangular through-hole and can be placed in the rectangular through-hole;

[0032] S5, aligning and stacking the anode upper layer, the anode middle layer, and the anode lower layer to form a laminated body, wherein the volatile layer film strips are placed in the rectangular through holes of the anode middle layer;

[0033] S6. Warm isostatically pressing the laminated green body, then cutting off both ends to expose both ends of the through hole to obtain a flat tube SOFC anode support green body, and then sintering the flat tube SOFC anode support to obtain a flat tube SOFC anode support.

[0034] Figure 2 : is a cross-sectional schematic diagram of the flat tube SOFC anode support body of the present invention; Figure 2 As shown, the flat tube SOFC anode support body 10 includes an anode upper layer 11, an anode middle layer 12 and an anode lower layer 13. The anode upper layer 11, the anode middle layer 12 and the anode lower layer 13 are stacked to form a rectangular cavity, and a volatile layer membrane strip 121 is provided in the rectangular cavity.

[0035] In the present invention, the flat tube SOFC anode support prepared by the lamination method is thin and high in strength. The total thickness of the single cell including the support can be controlled within 1 mm, and the proportion of channels in the anode support layer can be adjusted, which is beneficial to improving the fuel gas diffusion efficiency and stacking density.

[0036] The tape casting process of the present invention is mature, low-cost, requires minimal equipment, and is capable of mass production, thus possessing promising commercial prospects. In some preferred embodiments of the present invention, the anode layer membrane is prepared using a tape casting method; the tape casting method comprises: first ball milling 3YSZ-NiO composite powder, a solvent, and a dispersant, followed by a second ball milling with a binder and a plasticizer to produce an anode slurry, which is then tape-casted to produce the anode layer membrane.

[0037] FIG. 1 is a flow chart for preparing 3YSZ-NiO composite powder according to one embodiment of the present invention, as shown in FIG. Figure 3 As shown, the preparation method of the 3YSZ-NiO composite powder includes: uniformly mixing an insoluble nickel source with a solvent B to obtain an insoluble nickel source slurry, then mixing the insoluble nickel source slurry with a 3YSZ slurry; and annealing the resulting slurry. This method utilizes the fact that NiO and 3YSZ do not react with each other, uniformly mixing the 3YSZ slurry and the insoluble nickel source. This physical barrier prevents the agglomeration and growth of 3YSZ and NiO during the thermal process, resulting in uniform mixing of the primary particle size of 3YSZ and NiO. This prevents the agglomeration and growth of Ni formed after hydrogen reduction of the 3YSZ-NiO composite powder during high-temperature use, thereby improving the long-term stability of the battery.

[0038] In the present invention, the insoluble nickel source is a nickel-containing substance that does not react with solvent B and can form a slurry in solvent B, and the nickel-containing substance can decompose into nickel oxide under high temperature conditions. Preferably, the insoluble nickel source is selected from at least one of nickel carbonate, nickel hydroxide, and basic nickel carbonate. Preferably, the solid content of the insoluble nickel source slurry is 20-40wt%.

[0039] Preferably, the annealing conditions include: temperature of 700-1100° C., time of 1-6 h;

[0040] Preferably, the solvent B is selected from at least one of water and / or organic solvents; for example, it can be at least one of water, ethanol and propanol; in order to save costs and improve production safety, the solvent is preferably water.

[0041] In the present invention, the preparation method of the 3YSZ slurry may be known to those skilled in the art, for example, it may be a hydrothermal method or a co-precipitation method; in some preferred embodiments of the present invention, the method for preparing the 3YSZ slurry comprises: mixing a zirconium source and a yttrium source uniformly in a solvent at a pH of 8-10 to obtain a mixed solution, then subjecting the mixed solution to a hydrothermal reaction, and washing and filter-filtering the product obtained by the hydrothermal reaction to obtain a 3YSZ slurry.

[0042] During the process of drying 3YSZ slurry to prepare 3YSZ, 3YSZ is prone to agglomeration under the action of capillary force, which makes it difficult to mix 3YSZ and NiO evenly in the primary particle size during the subsequent mixing and sintering process; therefore, in this application, the 3YSZ slurry is not dried or directly annealed, but the 3YSZ slurry obtained by pressure filtration is directly used as a raw material to mix and react with an insoluble nickel source, which can avoid the agglomeration of 3YSZ and improve the mixing uniformity of 3YSZ and NiO in the product in the primary particle size.

[0043] In the present invention, the zirconium source is selected from soluble zirconium salts; the soluble zirconium salts may be known to those skilled in the art, including but not limited to at least one of zirconium oxychloride, zirconium nitrate, zirconium chloride and zirconium sulfate;

[0044] In the present invention, the yttrium source is selected from soluble yttrium salts, which are known to those skilled in the art and include but are not limited to at least one of yttrium nitrate, yttrium sulfate and yttrium chloride.

[0045] In the present invention, the pH value of the mixed solution is adjusted by a mineralizer, and the mineralizer can be any alkaline substance. The alkaline substance can be commonly known to those skilled in the art, including but not limited to ammonia water and sodium hydroxide.

[0046] In the present invention, the concentration of zirconium ions in the mixed solution can be adjusted according to actual needs, for example, it can be 0.5-1 mol / L.

[0047] According to the present invention, under preferred conditions, the hydrothermal reaction conditions include: temperature of 160-200° C., and reaction time of 10-30 h.

[0048] According to the present invention, preferably, the anode slurry comprises, by weight, 20-60% 3YSZ-NiO composite powder, 25-60% solvent A, 0.5-5% dispersant, 1-10% binder, and 1-10% plasticizer. Further preferably, the solvent A is selected from at least one of ethanol, xylene, butanone, and n-butanol; the dispersant is selected from at least one of phosphate esters, polyvinyl pyrrolidone, and triethanolamine; the binder is selected from at least one of PVA, PVB, and ethyl cellulose; and the plasticizer is selected from DBP and / or PEG.

[0049] Further preferably, the anode slurry is ball-milled at a rotation speed of 100-250 rpm for 12-24 h for the first time, and the anode slurry is ball-milled at a rotation speed of 100-250 rpm for 12-24 h for the second time.

[0050] In the present invention, the volatile layer membrane can prevent the rectangular cavity from deforming during warm isostatic pressing. Furthermore, the volatile layer membrane can oxidize and generate gas during the subsequent sintering (debinding) process, thereby forming a gas flow channel within the anode support. Specifically, the present invention uses the volatile layer membrane as a sacrificial template to prepare the gas flow channel. The present invention has no special requirements for the composition and preparation of the volatile layer membrane. Exemplarily, the volatile layer membrane preparation method includes: mixing a volatile layer powder, a solvent, and a dispersant, and then ball milling the mixture. After the mixture is ball milled, a binder and a plasticizer are mixed and mixed to prepare a volatile layer slurry, which is then tape-casted to form a volatile layer membrane. The volatile layer powder is any one or more of graphite powder, starch, and PMMA powder; the solvent is any one or more of ethanol, xylene, butanone, and n-butanol; the dispersant is any one or more of phosphate, polyvinyl pyrrolidone, and triethanolamine; the binder is any one or more of PVA, PVB, and ethyl cellulose; the plasticizer is one or two of DBP and PEG; the first ball milling speed of the volatile layer slurry is 100-250 rpm, and the ball milling time is 12-24 hours; the second ball milling speed is 100-250 rpm, and the ball milling time is 12-24 hours.

[0051] The flat tubular solid oxide fuel cell provided by the present invention is thin and occupies a small volume, which can increase the stacking density of the flat tubular solid oxide fuel cell. Specifically, more cells can be accommodated within a given stack volume. The thickness of the flat tubular solid oxide fuel cell can be controlled by adjusting the thickness of the anode upper layer, anode lower layer, and anode middle layer. Preferably, the thickness of the anode upper layer is 200-1000 μm; the thickness of the anode lower layer is 200-1000 μm; the thickness of the anode middle layer is 200-1000 μm; the thickness of the volatile layer membrane is 200-1000 μm; the anode layer is square; and the side length of the anode layer is preferably 50-200 mm.

[0052] In the present invention, by adjusting the length, width and spacing of the rectangular through holes in the anode intermediate layer, the volume of the rectangular cavity can be adjusted, thereby facilitating improving the utilization rate of gas during battery operation; under preferred conditions, the length of the rectangular through hole is 90%-100% of the length of the anode intermediate layer, preferably 95%-98%; preferably, the width of the rectangular through hole is 0.5-5mm; preferably, the spacing between two adjacent rectangular through holes is 0.5-5mm; preferably, the size of the volatile membrane strip is consistent with the size of the rectangular through hole.

[0053] In the present invention, the conditions for warm isostatic pressing include: temperature of 30-80° C., time of 1-10 min, and pressure of 5-40 MPa.

[0054] A second object of the present invention is to provide a flat tube SOFC anode support prepared according to the aforementioned method.

[0055] A third object of the present invention is to provide a flat tube solid oxide fuel cell, wherein the flat tube SOFC comprises, from the inside to the outside, a flat tube SOFC anode support, an anode functional layer, an electrolyte layer, and a cathode layer, wherein the flat tube SOFC anode support is the flat tube SOFC anode support described above;

[0056] The flat tube solid oxide fuel cell further includes a barrier layer disposed between the electrolyte layer and the cathode layer.

[0057] Figure 4 is a schematic cross-sectional view of a flat tubular solid oxide fuel cell in the present invention, as shown in FIG. Figure 4 As shown, the flat tube solid oxide fuel cell includes a flat tube SOFC anode support 1, an anode functional layer 2, an electrolyte layer 3, a barrier layer 4 and a cathode layer 5 from the inside to the outside, and a sealing layer 6 is also provided on both sides of the single cell; a gas flow channel 14 is provided in the flat tube SOFC anode support 1.

[0058] In some preferred embodiments of the present invention, the preparation method of the flat tube solid oxide fuel cell includes: silk-screening an anode functional layer and an electrolyte layer on the surface of the flat tube SOFC anode support in sequence, then adding an electrolyte sealing layer on the left and right sides of the flat tube SOFC anode support, and obtaining a half cell through debinding and sintering; wherein the anode functional layer is made of active powder, adhesive and solvent, wherein the active powder is NiO-8YSZ composite powder; the thickness of the anode functional layer is 10-20 μm.

[0059] In the present invention, the electrolyte layer is made of active powder, adhesive and solvent, wherein the active powder is 8YSZ powder; the thickness of the electrolyte layer is 10-20 μm.

[0060] The present invention adopts the dipping and pulling method to add the electrolyte sealing layer on both sides of the anode support. The electrolyte layer material is 8YSZ powder with a thickness of 10-20 μm.

[0061] In the present invention, the debinding temperature is 400-600°C, the debinding time is 1h-3h, the sintering temperature is 1300-1400°C, and the sintering time is 1-5h. The volatile membrane strips placed inside are completely volatilized by high-temperature ablation, leaving a flat tube anode support type half-cell.

[0062] A barrier layer is screen-printed on the upper and lower electrolyte layers of the flat tubular anode-supported half-cell using a screen-printing method. The barrier layer material is GDC powder with a screen-printing thickness of 3-5 μm. The barrier layer is then sintered at 1200-1300°C for 15 hours to form the barrier layer.

[0063] The cathode layer is screen-printed on the barrier layer by screen printing. The cathode layer material is LSCF powder with a screen printing thickness of 10-20 μm, and then sintered at 800-1200 ° C for 1 hour.

[0064] A third object of the present invention is to provide a fuel cell stack, comprising the aforementioned flat tube anode supported solid oxide fuel cell assembled.

[0065] The present invention is described in detail below through examples.

[0066] 1. Powder preparation

[0067] Preparation Example 1: Preparation of 3YSZ slurry

[0068] Dissolve zirconium oxychloride octahydrate and yttrium nitrate in water to obtain a solution, in which Zr 4+ The concentration is 0.97 mol / L; Y 3+ The concentration is 0.06 mol / L; then ammonia water is added to adjust the pH of the solution to 9 to obtain a mixed solution; then the mixed solution is hydrothermally reacted in a reactor at 180°C for 24 hours. After the reaction is completed, the obtained product is washed with an ion cleaner until no Cl is detected in the supernatant with silver nitrate solution. - ions are removed, and the washed product is filtered to obtain 3YSZ slurry.

[0069] Preparation Example 2: Preparation of 3YSZ-NiO-1 powder

[0070] Basic nickel carbonate was added to deionized water and stirred and ground for 24 hours to obtain a basic nickel carbonate slurry with a solid content of 40 wt%.

[0071] The 3YSZ powder and basic nickel carbonate slurry (according to the weight ratio of 3YSZ slurry to NiO being 1:1.8) were mixed and ground, and then the ground mixture was dried at 80°C for 24 hours; the dried product was sintered at 1000°C for 2 hours, and then the sintered product was air flow-pulverized to obtain 3YSZ-NiO-1 composite powder.

[0072] Preparation Example 3: Preparation of 3YSZ-NiO-2 powder

[0073] The method of Preparation Example 2 was followed, except that 3YSZ was dried at 80°C for 24 h to obtain 3YSZ powder;

[0074] NiO powder was obtained by directly pyrolyzing basic nickel carbonate at 1000℃.

[0075] 3YSZ powder and NiO powder were mixed in a weight ratio of 1:1.8, and then water was added and ball milled for 24 hours; the ground mixture was then dried at 80°C for 24 hours; and the mixed product was then air-milled to obtain 3YSZ-NiO-2 composite powder.

[0076] Test Example 1

[0077] Using terpineol as a solvent, 90 wt% of anode support powder and 10 wt% of ethyl cellulose were ball-milled and mixed. A 10 cm × 10 cm anode support layer green body was then prepared using a tape casting process. Ten 1 cm × 10 cm anode support layer green bodies were cut from the same green body. The anode support layer green bodies were sintered at 1330°C and then reduced in pure hydrogen at 750°C for 2 h to obtain the anode support layer. The electrical conductivity and average three-point flexural strength of the ten anode support layers were tested. The experimental results are shown in Tables 1 and 2.

[0078] Among them, the three-point flexural strength is obtained by testing with a universal material testing machine;

[0079] The electrical conductivity was measured by a digital multimeter using the four-probe method at a temperature of 750°C;

[0080] Table 1

[0081]

[0082] As can be seen in Table 1, the anode support layer made from the 3YSZ-NiO-1 composite powder has a more stable conductivity, consistently above 1000 S / cm, while the conductivity of the anode support layer made from the 3YSZ-NiO-2 composite powder is extremely unstable, ranging from a minimum of 46 S / cm to a maximum of 2430 S / cm. This further demonstrates that the 3YSZ and NiO in 3YSZ-NiO-1 are more uniformly mixed than in 3YSZ-NiO-2.

[0083] Table 2

[0084]

[0085] Note: The average conductivity is the average conductivity of 10 anode support layers prepared from the same anode powder;

[0086] The average three-point flexural strength is the average value of the three-point flexural strengths of 10 anode support layers prepared from the same anode powder.

[0087] It can be seen from Table 2 that the anode support layer made of 3YSZ-NiO-1 composite powder has higher three-point flexural strength.

[0088] Preparation Examples 4-6

[0089] The method of Preparation Example 2 was followed, except that the annealing temperature was as shown in Table 3.

[0090] The composite powders prepared in Preparation Examples 4-6 were made into anode support layers (preparation method was the same as that in Test Example 1). The experimental results are shown in Table 3.

[0091] The porosity of the anode support after reduction is measured using a water drainage method.

[0092] Table 3

[0093]

[0094] Table 3 shows that within the 800°C-1000°C range, the flexural strength and electrical conductivity of the anode support decrease with increasing heat treatment temperature. This is likely because increasing heat treatment temperature increases the primary particle size of the powder and reduces its specific surface area, which in turn reduces the sintering activity of the powder, resulting in less dense sintering of the anode support and, consequently, reduced flexural strength and electrical conductivity. This is also evident from the porosity of the anode support after reduction, which increases with increasing heat treatment temperature, indicating a continuous decrease in the density of the anode support after sintering. Since the anode support itself requires sufficient porosity to allow the anode fuel gas to reach the three-phase interface where the oxidation reaction occurs, porosity must be considered as a factor when selecting the anode support material.

[0095] 2. SOFC Half-Cell Preparation

[0096] Example 1

[0097] 1. Preparation of anode support body

[0098] 1) adding ethanol, butanone, and triethanolamine to 3YSZ-NiO-1 and ball milling at 150 rpm for 24 h, then adding PVB, DBP, and PEG and ball milling at 150 rpm for 24 h to prepare an anode support slurry, casting the anode support slurry on a tape casting machine to obtain an anode layer membrane having an anode upper layer, an anode middle layer, and an anode lower layer, each with a thickness of 300 μm, cutting the anode layer membrane (the anode upper layer, the anode middle layer, and the anode lower layer) into a number of square membranes with uniform dimensions (length × width × thickness: 100 mm × 100 mm × 300 μm), and processing rectangular through holes on the anode middle layer membrane by laser cutting or mechanical stamping, wherein the through holes have a length of 95 mm and a width of 1 mm, and a spacing of 1 mm between two adjacent rectangular through holes;

[0099] In order to obtain anode layer cast membrane with better quality, this embodiment adjusts the content of different components in the anode slurry to obtain cast membranes with different states. After comprehensive comparison, the optimal ratio of the anode slurry is obtained. The states of cast membranes with different components are shown in Table 4 below.

[0100] Table 4

[0101]

[0102]

[0103] 2) adding ethanol, butanone, and triethanolamine to graphite powder and ball-milling at 150 rpm for 24 h. Then, adding PVB, DBP, and PEG and ball-milling at 150 rpm for 24 h to prepare a volatile film slurry. The volatile film slurry was cast on a tape casting machine to obtain a volatile film sheet with a thickness of 300 μm. The volatile film sheet was cut into square films with uniform dimensions (length × width × thickness: 100 mm × 100 mm × 300 μm). The volatile film sheet was cut into rectangular volatile film strips using laser cutting, and the film strips had the same dimensions as the rectangular through-holes.

[0104] The composition of the volatile film slurry is as follows:

[0105]

[0106] 3) Laminating an anode middle layer membrane with rectangular through holes on an anode lower layer membrane, then filling each rectangular through hole of the anode middle layer with a rectangular volatile membrane strip, and finally laminating an anode upper layer membrane on the anode support middle layer membrane to form a laminated body;

[0107] 4) performing warm isostatic pressing on the laminated green body at 60° C. and 20 MPa for 5 minutes, and then cutting off 3 mm from each end of the green body on a hot cutter to expose the end surface of the rectangular through hole, thereby obtaining an anode support green body;

[0108] 2. Preparation of half-cell

[0109] 1) preparing an anode functional layer on the upper and lower surfaces of the anode support body by screen printing, wherein the thickness of the anode functional layer is 15 μm;

[0110] The composition of the anode functional layer slurry is as follows:

[0111]

[0112] 2) Screen printing an electrolyte layer on the surface of the anode functional layer with a thickness of 15 μm; then adding an electrolyte sealing layer with a thickness of 15 μm on both sides of the anode support body by dip-coating to obtain a half-cell body;

[0113] The electrolyte layer slurry composition is as follows:

[0114]

[0115] 3) The prepared half-cell body was debinded at 450°C for 2 hours and then sintered at 1400°C for 3 hours to obtain a flat tubular anode-supported half-cell with a through-hole structure and a thickness of 0.69 mm;

[0116] 3. Preparation of solid oxide fuel cells

[0117] A GDC barrier layer was screen-printed on the surface of a flat-tube anode-supported half-cell with a thickness of 3 μm, and sintered at 1250°C for 2 hours to form a barrier layer. Finally, an LSCF cathode layer was screen-printed on the barrier layer with a thickness of 20 μm, and then sintered at 1100°C for 1 hour to obtain a flat-tube solid oxide fuel cell.

[0118] The composition of GDC barrier layer slurry is as follows:

[0119]

[0120] The LSCF cathode layer slurry composition is as follows:

[0121]

[0122]

[0123] Example 2

[0124] The method of Example 1 is followed, except that a rectangular through hole is machined on the anode support intermediate layer membrane by mechanical stamping. The through hole has a length of 95 mm and a width of 2 mm, and the distance between two adjacent rectangular through holes is 1 mm.

[0125] Example 3

[0126] The method of Example 1 is followed, except that a rectangular through hole is machined on the anode support intermediate layer membrane by mechanical stamping. The through hole has a length of 95 mm and a width of 3 mm, and the distance between two adjacent rectangular through holes is 1 mm.

[0127] Example 4

[0128] The method of Example 1 is followed, except that a rectangular through hole is machined on the anode support intermediate layer membrane by mechanical stamping. The through hole has a length of 95 mm and a width of 1 mm, and the distance between two adjacent rectangular through holes is 2 mm.

[0129] Example 5

[0130] The method of Example 1 is followed, except that a rectangular through hole is machined on the anode support intermediate layer membrane by mechanical stamping. The through hole has a length of 95 mm and a width of 1 mm, and the distance between two adjacent rectangular through holes is 3 mm.

[0131] Example 6

[0132] The method of Example 1 is followed, except that a rectangular through hole is machined on the anode support intermediate layer membrane by mechanical stamping. The through hole has a length of 95 mm and a width of 1 mm, and the distance between two adjacent rectangular through holes is 0.5 mm.

[0133] Example 7

[0134] The method of Example 1 is followed, except that the anode support slurry is cast on a tape casting machine to obtain an anode upper layer and an anode lower layer with a thickness of 200 μm, and an anode middle layer with a thickness of 300 μm; the volatile film layer slurry is cast on a tape casting machine to obtain a volatile layer membrane with a thickness of 300 μm; and rectangular through holes are processed on the anode support middle layer membrane by laser cutting or mechanical punching. The through holes have a length of 95 mm and a width of 3 mm, and the spacing between two adjacent rectangular through holes is 1 mm.

[0135] The performance of the flat tube SOFC anode support in Examples 1-7 is shown in Table 5.

[0136] Table 5

[0137]

[0138] The gas flow channel ratio* refers to the ratio of the volume of the gas flow channel to the total volume of the support body.

[0139] As shown in Table 5, the present invention can prepare green bodies of different thicknesses by tape-casting different anode layer thicknesses, and the total green body thickness can be controlled within 1 mm. By designing different cavity width dimensions and cavity spacing, the ratio of the pore volume to the green body volume can be adjusted, which is beneficial to optimizing the fuel gas flow efficiency of the solid oxide fuel cell and increasing the number of single cells assembled during stack assembly.

[0140] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a flat tube SOFC anode support, characterized in that: The steps include: S1, preparing an anode layer membrane and a volatile layer membrane; S2, using the anode layer membrane as an anode upper layer, an anode middle layer and an anode lower layer respectively; S3, processing a plurality of rectangular through holes on the anode intermediate layer; S4, cutting the volatile layer film sheet into volatile layer film strips, wherein the size of the volatile layer film strips matches the size of the rectangular through hole and can be placed in the rectangular through hole; S5, aligning and stacking the anode upper layer, the anode middle layer, and the anode lower layer to form a laminated body, wherein the volatile layer film strips are placed in the rectangular through holes of the anode middle layer; S6. warm isostatically pressing the laminated green body, then cutting off both ends to expose both ends of the through-hole to obtain a flat tube anode support green body, and then sintering the flat tube anode support to obtain a flat tube SOFC anode support; The anode layer membrane is prepared by a tape casting method, which includes: performing a first ball milling on 3YSZ-NiO composite powder, a solvent and a dispersant, then adding a binder and a plasticizer and performing a second ball milling to obtain an anode slurry, and then tape casting the anode slurry to prepare the anode layer membrane. The preparation method of the 3YSZ-NiO composite powder includes: uniformly mixing an insoluble nickel source with a solvent B to obtain an insoluble nickel source slurry, then mixing the insoluble nickel source slurry with a 3YSZ slurry; and annealing the mixed slurry. The method for preparing the 3YSZ slurry includes: uniformly mixing a zirconium source and a yttrium source in a solvent at a pH of 8-10 to obtain a mixed solution, then subjecting the mixed solution to a hydrothermal reaction, and washing and filter-filtering the product obtained by the hydrothermal reaction to obtain a 3YSZ slurry.

2. The method according to claim 1, characterized in that The components of the anode slurry include, by weight, 20-60% of 3YSZ-NiO composite powder, 25-60% of solvent A, 0.5-5% of dispersant, 1-10% of adhesive, and 1-10% of plasticizer.

3. The method according to claim 1, characterized in that The solid content of the insoluble nickel source slurry is 20-40 wt %.

4. The method according to claim 1, wherein The annealing conditions include: a temperature of 700-1100° C. and a time of 1-6 hours.

5. The method according to claim 1, characterized in that The solvent B is selected from at least one of water and / or organic solvents.

6. The method according to claim 1, characterized in that The insoluble nickel source is selected from at least one of nickel carbonate, nickel hydroxide and basic nickel carbonate.

7. The method according to claim 1, characterized in that The solvent A is selected from at least one of ethanol, xylene, butanone and n-butanol.

8. The method according to claim 1, characterized in that The dispersant is selected from at least one of phosphate, polyvinyl pyrrolidone and triethanolamine.

9. The method according to claim 1, characterized in that The binder is selected from at least one of PVA, PVB and ethyl cellulose.

10. The method according to claim 1, characterized in that The plasticizer is selected from DBP and / or PEG.

11. The method according to claim 1, wherein The rotation speed of the first ball milling of the anode slurry is 100-250 rpm, and the ball milling time is 12-24 hours.

12. The method according to claim 1, characterized in that The rotation speed of the second ball milling is 100-250 rpm, and the ball milling time is 12-24 hours.

13. The method according to any one of claims 1 to 12, characterized in that The thickness of the anode upper layer is 200-1000 μm.

14. The method according to any one of claims 1 to 12, characterized in that The thickness of the anode lower layer is 200-1000 μm.

15. The method according to any one of claims 1 to 12, characterized in that The thickness of the anode intermediate layer is 200-1000 μm.

16. The method according to any one of claims 1 to 12, characterized in that The thickness of the volatile layer membrane is 200-1000 μm.

17. The method according to any one of claims 1 to 12, characterized in that The anode layer is square; the side length of the anode layer is 50-200 mm.

18. The method according to claim 13, characterized in that The length of the rectangular through hole is 90%-100% of the length of the anode intermediate layer.

19. The method according to claim 18, characterized in that The length of the rectangular through hole is 95%-98% of the length of the anode intermediate layer.

20. The method according to claim 19, characterized in that The width of the rectangular through hole is 0.5-5 mm.

21. The method according to claim 18, wherein The distance between two adjacent rectangular through holes is 0.5-5 mm.

22. The method according to claim 18, wherein The size of the volatile layer film strip is consistent with the size of the rectangular through hole.

23. The method according to claim 1, wherein The conditions of the warm isostatic pressing include: temperature of 30-80° C., time of 1-10 min, and pressure of 5-40 MPa.

24. A flat tube SOFC anode support prepared according to the method according to any one of claims 1 to 23.

25. A flat tube solid oxide fuel cell, comprising, from the inside out, a flat tube SOFC anode support, an anode functional layer, an electrolyte layer, and a cathode layer, characterized in that: The flat tube SOFC anode support is the flat tube SOFC anode support according to claim 24.

26. The flat tube solid oxide fuel cell according to claim 25, characterized in that: The flat tube solid oxide fuel cell further includes a barrier layer disposed between the electrolyte layer and the cathode layer.

27. A fuel cell stack formed by assembling the flat tube anode supported solid oxide fuel cell according to claim 25 or 26.

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