A green multilayer co-fired SOFC flat plate single cell stack and a preparation method thereof

Abstract

The application relates to the technical field of solid oxide fuel cells, and discloses a green body multilayer co-firing SOFC flat plate single cell stack and a preparation method, which comprises the following steps: S1, multilayer co-firing treatment: S101, silk printing AFL: preparing a sheet type anode green body raw material, silk screen printing AFL on the surface of the sheet type anode green body raw material, and then sequentially performing low-temperature drying, wet smoothing and natural drying; S102, silk printing YSZ: silk screen printing YSZ on the AFL surface of the dried sheet type anode green body obtained in the step S101, and then sequentially performing low-temperature drying and wet smoothing. By reducing the sintering times, the porosity reduction of the anode support caused by multiple sintering is avoided, the gas transmission rate and the electrochemical performance of the cell are further improved under the premise of ensuring the mechanical strength of the cell, and by means of low-temperature drying and wet smoothing, warping is avoided, the thickness of the functional layer is uniform, the co-sintering temperature is further reduced, and the influence of the formation of a highly insulated solid solution phase of the electrolyte layer YSZ and the barrier layer GDC under high temperature on the cell performance is avoided.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, specifically to a green multilayer co-fired SOFC planar single-cell stack and its preparation method. Background Technology

[0002] Solid oxide fuel cells (SOFCs) belong to the third generation of fuel cells. They are all-solid-state chemical power generation devices that directly convert the chemical energy stored in fuel and oxidant into electrical energy at medium and high temperatures in an efficient and environmentally friendly manner. Among the various types of fuel cells, SOFCs have the highest theoretical energy density and are widely regarded as a type of fuel cell that will be widely used in the future, just like proton exchange membrane fuel cells (PEMFCs).

[0003] Planar SOFCs offer advantages such as short current flow, low power loss, high power density, and simple structure. To further improve battery performance, thinning of the planar support has become a growing trend. To reduce costs and sintering cycles and increase porosity in the anode support, multi-layer co-firing directly on the anode greenstock yields a planar half-cell. However, during the fabrication of greenstock planar single cells, warping is easily caused, affecting the uniformity of functional layers and stacking performance. Furthermore, at sintering temperatures above 1300℃, the electrolyte layer (YSZ) and barrier layer (GDC) form highly insulating solid solutions at the interfaces, further impacting single-cell performance. Additionally, traditional solid oxide fuel cell stacks cannot circulate the input fuel gas and air through their fuel gas and air channels, leading to insufficient utilization of fuel gas and air and increased economic costs. Therefore, this paper proposes a greenstock multi-layer co-firing SOFC planar single-cell stack and its fabrication method to address these issues. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a green-mounted multilayer co-fired SOFC planar single-cell stack and its preparation method. This invention solves the problems that occur easily during the preparation of existing green-mounted planar single-cell stacks, which can lead to warping, affecting the uniformity of functional layers and stacking performance. It also addresses the issue that when the electrolyte layer YSZ and the barrier layer GDC are sintered at excessively high temperatures, highly insulating solid solutions form at the interface, thus affecting the performance of the single cell.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a green multilayer co-fired SOFC flat single cell stack, characterized in that it includes a support frame one and a support frame two, and a sheet single cell assembly engaged between the support frame one and the support frame two.

[0006] Both sides of the first support frame are provided with mortises, and both sides of the second support frame are provided with tenons. The tenons and mortises engage with each other. The adjacent sides of the first support frame and the second support frame are connected by the tenons and mortises. Several return cavities are provided at equal intervals on the inward side of the first support frame and the second support frame.

[0007] The single-cell assembly includes a flow guide. The top of the flow guide has several oxidant flow channels arranged laterally, and the bottom of the flow guide has several fuel flow channels arranged longitudinally. A return hole is provided between each pair of adjacent oxidant flow channels, and a return hole is also provided between each pair of adjacent fuel flow channels. A single-cell assembly is disposed at both the top and bottom of the flow guide. Each single-cell assembly includes an anode layer, an electrolyte layer, and a cathode layer. An end plate is stacked on the outer side of each single-cell assembly. The bottom of the upper end plate has several fuel flow channels arranged longitudinally at equal intervals, and the top of the lower end plate has several oxidant flow channels arranged laterally at equal intervals. Each side of the oxidant flow channel and the fuel flow channel corresponds to a return cavity in its respective orientation.

[0008] Preferably, keyholes are provided on the top and bottom left and right sides of the support frame one and support frame two, and a locking pin is engaged in each keyhole. The top of the locking pin is fixedly installed at the four corners of the bottom of the pressure plate, and a pressure end strip is fixedly installed on the inner wall of the pressure plate.

[0009] Preferably, the first support frame includes two support frames 1 arranged opposite to each other, and the second support frame includes two support frames 2 arranged opposite to each other. An oxidant inlet is fixedly installed on the outward side of one of the first support frames, and a fuel inlet is fixedly installed on the outward side of one of the second support frames. The fuel inlet and the oxidant inlet are respectively connected to their respective reflux chambers.

[0010] Preferably, the fuel inlet and the oxidant inlet are provided with seals, and gas sealing materials are provided on both the oxidant flow path and the fuel flow path to prevent gas leakage and mixing.

[0011] A method for preparing a green-mounted multilayer co-fired SOFC planar single-cell stack, using the aforementioned green-mounted multilayer co-fired SOFC planar single-cell stack, includes the following steps:

[0012] S1, Multi-layer co-firing treatment:

[0013] S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence;

[0014] S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing.

[0015] S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing.

[0016] S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell;

[0017] S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing.

[0018] S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate.

[0019] S4. Assemble and seal the single-cell flat panel with support frame one, support frame two, current guide, end plate, and pressure plate to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

[0020] Preferably, the low-temperature drying temperature for the screen-printed AFL, YSZ, and GDC is 40-50℃, and the drying time is 10-12h; the drying temperature for the screen-printed cathode is 100-110℃, and the drying time is 20-30min.

[0021] Preferably, the specific steps of wetting and smoothing are as follows: use a lint-free cloth to wet the unscreened side of the sheet anode green blank, then attach the two sheet anode green blanks together with their respective screen-screened sides, and apply pressure to smooth the unscreened side of the two sheet anode green blanks under the action of a firing plate or other pressure device.

[0022] Preferably, the wetting and smoothing temperature of the screen printing AFL, YSZ, and GDC is 40-50℃, and the pressure is 0.1-0.2MPa.

[0023] Preferably, the temperature of the multi-layer co-firing treatment is 1280-1290℃, and the holding time is 2-3h; the sintering temperature of the sintering treatment is 1040-1050℃, and the sintering time is 2-3h.

[0024] Preferably, the AFL is obtained by screen printing with AFL paste. By weight, the AFL paste is obtained by mixing raw materials comprising the following components: 0.35-0.40 parts of nickel oxide powder, 0.3-0.35 parts of YSZ powder, 0.3-0.35 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, and 0.01-0.02 parts of dispersant;

[0025] The YSZ is obtained by screen printing YSZ slurry. By weight, the YSZ slurry is obtained by mixing raw materials including the following components: 0.45-0.55 parts of YSZ powder, 0.40-0.45 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, 0.02-0.04 parts of dispersant, and 0.01-0.02 parts of plasticizer.

[0026] The GDC is obtained by screen printing GDC slurry. By weight, the GDC slurry is obtained by mixing raw materials including the following components: 0.5-0.55 parts GDC powder, 0.35-0.40 parts solvent, 0.01-0.02 parts suspending stabilizer, 0.01-0.02 parts binder, and 0.02-0.03 parts dispersant.

[0027] Preferably, the solvent includes terpineol; the suspension stabilizer includes ethyl cellulose; the binder includes polyvinyl butyral (PVB); the dispersant includes triethanolamine, and the dispersant in the GDC slurry includes, in addition to triethanolamine, one or more of polyvinylpyrrolidone (PVP), fish oil, and furoic acid; the plasticizer includes polyethylene glycol and / or dibutyl phthalate.

[0028] Working Principle: This invention utilizes two pairs of interlocking support frames (SFrame 1 and SFrame 2) to form the overall peripheral support frame of the SOFC flat-plate single-cell stack. Further fixation of SFrame 1 and SFrame 2 is achieved through the interlocking of keyholes, locking posts, and edge plates. Simultaneously, the end-pressing strips on the edge plates fix, limit, and compact the functional layers. The functional layers are mainly composed of a central flow guide, sheet-like single cells above and below the flow guide, and end plates covering the outer sides of the sheet-like single cells. These layers are stacked to form the functional layers. During operation, fuel and oxidant are input through the fuel inlet and oxidant inlet, flowing in the oxidant flow channel and fuel flow channel, respectively. After flowing through the entire oxidant flow channel and fuel flow channel, the fuel and oxidant will... Fuel and oxidant accumulate in the reflux chambers on the inner walls of support frame one and support frame two. Due to the injection of oxidant and fuel flow channels, fuel and oxidant fill the channels of oxidant and fuel flow channels respectively. At this time, the reflux holes set in the transverse and longitudinal directions of the guide will output the fuel and oxidant in the reflux chamber back. As for the channels for inputting fuel and oxidant, due to the pressurized input of the input port and oxidant input port, they enter the oxidant and fuel flow channels at a relatively fast speed. Therefore, they will not be input through the discharge position of the reflux holes. Instead, the fuel and oxidant flowing out of the reflux holes will cooperate with the newly entered fuel and oxidant. Through its high flow rate, it will drive the low flow rate of fuel and oxidant to be input, cooperate with the prepared planar single cell to react, and complete its operation process.

[0029] This invention provides a green multilayer co-fired SOFC planar single-cell stack and its preparation method.

[0030] It has the following beneficial effects:

[0031] 1. By reducing the number of sintering cycles and avoiding the decrease in porosity of the anode support caused by multiple sintering cycles, this invention further improves the gas transport rate and electrochemical performance of the battery while ensuring the mechanical strength of the battery.

[0032] 2. This invention solves the warping phenomenon caused during the preparation of green flat single cells by using multi-layer co-firing treatment, as well as low-temperature drying and wetting smoothing, resulting in uniform functional layer thickness and better subsequent stacking effect.

[0033] 3. This invention reduces the co-sintering temperature on the basis of multi-layer co-firing of green blanks, thereby avoiding the formation of highly insulating solid solution phases in the electrolyte layer YSZ and barrier layer GDC at high temperatures, which would affect battery performance.

[0034] 4. This invention utilizes a reflux channel to recirculate fuel and oxidant, which on the one hand saves input fuel and oxidant, and on the other hand makes their contact reaction with the flat single cell more complete, better consumes the overall input of fuel and oxidant, and saves economic costs. Attached Figure Description

[0035] Figure 1 This is a perspective view of the present invention;

[0036] Figure 2 This is a schematic diagram of the disassembled structure of the present invention;

[0037] Figure 3 This is a schematic diagram showing the disassembled structure of support frame one and support frame two of the present invention;

[0038] Figure 4 This is a schematic diagram of the flow guide of the present invention;

[0039] Figure 5 This is a schematic diagram of the reflux cavity structure of the present invention;

[0040] Figure 6 This is a schematic diagram of the fabrication process of the chip single cell of the present invention;

[0041] Figure 7 This is a schematic diagram of the wetting and smoothing process of the present invention;

[0042] Figure 8 This is a schematic diagram comparing the sintering temperatures of the YSZ electrolyte layer in this invention.

[0043] Figure 9 A schematic diagram of the IV curves of a button cell prepared by stepwise firing and a button cell prepared by multi-layer co-firing of the green blank according to the present invention.

[0044] Among them, 1. Support frame one; 2. Support frame two; 3. Tenon; 4. Mortise; 5. Return chamber; 6. Keyhole; 7. Fuel inlet; 8. Oxidant inlet; 9. Locking post; 10. Edge plate; 11. End bar; 12. Flow guide; 13. Oxidant flow channel; 14. Fuel flow channel; 15. Return hole; 16. Single-cell plate; 17. End plate. Detailed Implementation

[0045] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0046] Example 1:

[0047] According to one aspect of the invention, please refer to the appendix. Figure 1 ~Attached Figure 5 This invention provides a green multilayer co-fired SOFC flat single cell stack, including a support frame 1 and a support frame 2, and a single cell assembly snapped between the support frame 1 and the support frame 2.

[0048] Both sides of support frame 1 are provided with mortises 4, and both sides of support frame 2 are provided with tenons 3. The tenons 3 and mortises 4 engage with each other. The adjacent sides of support frame 1 and support frame 2 are connected by tenons 3 and mortises 4. Several return cavities 5 are provided at equal intervals on the inward side of support frame 1 and support frame 2. In this embodiment, preferably, support frame 1 and support frame 2 can be made of ceramic material.

[0049] The single-cell assembly includes a flow guide 12. The top of the flow guide 12 has several oxidant flow channels 13 arranged laterally, and the bottom of the flow guide 12 has several fuel flow channels 14 arranged longitudinally. A return hole 15 is provided between each adjacent oxidant flow channel 13, and a return hole 15 is also provided between each adjacent fuel flow channel 14. Single-cell assemblies 16 are mounted at both the top and bottom of the flow guide 12. Each single-cell assembly 16 includes an anode layer, an electrolyte layer, and a cathode layer. An end plate 17 is stacked on the outward side of each single-cell assembly 16. The bottom of the upper end plate 17 has several fuel flow channels 14 arranged longitudinally at equal intervals, and the top of the lower end plate 17 has several oxidant flow channels 13 arranged laterally at equal intervals. Each side of the oxidant flow channel 13 and the fuel flow channel 14 has a corresponding return cavity 5. In this embodiment, preferably, the flow guide 12 can be made of stainless steel.

[0050] The top and bottom left and right sides of the support frame 1 and the support frame 2 are provided with keyholes 6, and lock pins 9 are engaged in the keyholes 6. The top of the lock pins 9 are fixedly installed at the four corners of the bottom of the pressure plate 10, and pressure end strips 11 are fixedly installed on the inner wall of the pressure plate 10.

[0051] Support frame 1 includes two support frames 1 arranged opposite to each other, and support frame 2 includes two support frames 2 arranged opposite to each other. An oxidant inlet 8 is fixedly installed on the outward side of one of the support frames 1, and a fuel inlet 7 is fixedly installed on the outward side of one of the support frames 2. The fuel inlet 7 and the oxidant inlet 8 are respectively connected to their respective return chambers 5.

[0052] In this embodiment, preferably, seals are provided at the fuel inlet 7 and the oxidant inlet 8, and gas sealing materials are provided on both the oxidant flow path and the fuel flow path to prevent gas leakage and mixing. This embodiment of the battery stack structure has good sealing performance. To further ensure sealing, the aforementioned seals and gas sealing materials can be provided. The form of the seals and gas sealing materials is not limited, as long as they can prevent gas leakage and direct mixing of the two gases. For example, high-temperature sealing rings, gaskets, or silica slurry coatings, etc.

[0053] Compared with the prior art, the present invention utilizes the interlocking of two pairs of support frames 1 and 2 to form the overall peripheral support frame of the SOFC flat single battery stack. At the same time, the support frames 1 and 2 are further fixed by the interlocking of the keyhole 6, the locking post 9, and the pressure plate 10. Meanwhile, the pressure end strip 11 on the pressure plate 10 fixes, limits the edge and compacts the functional layer, ensuring stability and sealing.

[0054] Secondly, fuel and oxidant are input through fuel inlet 7 and oxidant inlet 8, and flow in oxidant flow channel 13 and fuel flow channel 14, respectively. After flowing through the entire oxidant flow channel 13 and fuel flow channel 14, the fuel and oxidant accumulate in the return cavity 5 on the inner wall of support frame 1 and support frame 2. Due to the injection into oxidant flow channel 13 and fuel flow channel 14, the fuel and oxidant occupy the channels of oxidant flow channel 13 and fuel flow channel 14, respectively. At this time, the return flow in the transverse and longitudinal directions of the guide member 12... The orifice 15 will output the fuel and oxidant in the return chamber 5 back, while the channels for inputting fuel and oxidant, due to the pressurized input at the inlet 7 and oxidant inlet 8, enter the oxidant flow channel 13 and fuel flow channel 14 at a relatively fast speed. Therefore, it will not be input through the discharge position of the return orifice 15. The fuel and oxidant flowing out of the return orifice 15 will cooperate with the newly entered fuel and oxidant, and the high flow rate will drive the low flow rate of fuel and oxidant to be input, which will cooperate with the prepared planar single cell to react and complete its operation process.

[0055] Example 2:

[0056] According to another aspect of the invention, please refer to the appendix. Figure 6 ~Attached Figure 9 This invention provides a method for preparing a green multilayer co-fired SOFC planar single-cell stack, comprising the following steps:

[0057] S1, Multi-layer co-firing treatment:

[0058] S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence;

[0059] S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing.

[0060] S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing.

[0061] S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell;

[0062] S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing.

[0063] S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate.

[0064] S4. Assemble and seal the single-cell flat panel with support frame 1, support frame 2, current guide 12, end plate 17, and edge plate 10 to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

[0065] Furthermore, the low-temperature drying temperature for screen printing AFL, YSZ, and GDC is 40-50℃, and the drying time is 10-12 hours.

[0066] The drying temperature of the screen printing cathode is 100-110℃, and the drying time is 20-30 minutes.

[0067] Furthermore, the temperature for multi-layer co-firing is 1280-1290℃, and the holding time is 2-3 hours;

[0068] The sintering temperature for the sintering treatment is 1040-1050℃, and the sintering time is 2-3h.

[0069] Specifically, to lower the sintering temperature of YSZ and GDC, the formulations of YSZ and GDC slurries were adjusted and optimized. Furthermore, the shrinkage of the green body during sintering caused the shrinkage of the multi-layer functional layers, resulting in a multi-layer co-firing temperature <1290℃. Figure 8 and Figure 9 As shown. Specifically: During the sintering process of the green body to obtain the support, there will be some shrinkage A. If a film is applied to the support before sintering, there will also be some shrinkage B. If the film is applied directly to the green body and then sintered, the total shrinkage is A+B. This will also cause the film layer to shrink even more. At the same sintering temperature, greater shrinkage results in better density. In other words, under the same density, the sintering temperature required for direct film application to the green body is lower, i.e., the sintering temperature can be reduced.

[0070] Further, the specific steps for wetting and smoothing are as follows: Use a lint-free cloth to wet the unscreened side of the sheet anode green blank, then attach the two sheet anode green blanks together with their respective screen-screened sides, and apply pressure to smooth the unscreened side of the two sheet anode green blanks under the action of the firing plate or other pressure device.

[0071] Furthermore, the wetting and smoothing temperature for screen printing AFL, YSZ, and GDC is 40-50℃, and the pressure is 0.1-0.2MPa.

[0072] Specifically, the screen-printed green blanks are dried at a low temperature to prevent the film layer from sticking. However, even at a low temperature of 40-50℃, the green blanks may still warp. In this case, wetting and smoothing are necessary. This is done by wetting the uncoated side with a lint-free cloth, then placing the two green blanks with their film layers facing each other and smoothing them under the pressure of a firing plate or other pressure device. Smoothing should also be done at a temperature of 40-50℃. If smoothing is done directly without wetting, the green blanks will still warp after the pressure is released. Wetting before smoothing can eliminate warping under pressure. Figure 7 .

[0073] Furthermore, AFL is obtained by screen printing AFL paste. By weight, AFL paste is obtained by mixing raw materials including the following components: 0.35-0.40 parts of nickel oxide powder, 0.3-0.35 parts of YSZ powder, 0.3-0.35 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, and 0.01-0.02 parts of dispersant;

[0074] YSZ is obtained by screen printing YSZ slurry. By weight, YSZ slurry is obtained by mixing raw materials including the following components: 0.45-0.55 parts of YSZ powder, 0.40-0.45 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, 0.02-0.04 parts of dispersant, and 0.01-0.02 parts of plasticizer;

[0075] GDC is obtained by screen printing GDC slurry. By weight, GDC slurry is obtained by mixing raw materials including the following components: 0.5-0.55 parts GDC powder, 0.35-0.40 parts solvent, 0.01-0.02 parts suspending stabilizer, 0.01-0.02 parts binder, and 0.02-0.03 parts dispersant.

[0076] Solvents include terpineol; suspension stabilizers include ethyl cellulose; binders include polyvinyl butyral (PVB); dispersants include triethanolamine, and in addition to triethanolamine, dispersants in GDC slurries also include one or more of polyvinylpyrrolidone (PVP), fish oil, and furoic acid; plasticizers include polyethylene glycol and / or dibutyl phthalate.

[0077] Specifically, the mixture of ethyl cellulose and PVP can act as a thickener. Cellulose increases viscosity through the entanglement of molecular chains, which can effectively improve the suspension stability of the slurry. PVP can not only act as a thickener to stabilize the slurry state, but also as an effective dispersant to make the particles disperse more evenly.

[0078] Dibutyl phthalate and polyethylene glycol are used as plasticizers. Dibutyl phthalate can lubricate powder particles and reduce viscosity, while polyethylene glycol forms organic bridges between powder particles and can increase viscosity. A certain ratio of the two can effectively adjust the viscosity of the slurry.

[0079] Example 3:

[0080] According to another aspect of the present invention, an embodiment of the present invention provides a method for preparing a green multilayer co-fired SOFC planar single-cell stack, comprising the following steps:

[0081] S1, Multi-layer co-firing treatment:

[0082] S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence;

[0083] S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing.

[0084] S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing.

[0085] S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell;

[0086] S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing.

[0087] S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate.

[0088] S4. Assemble and seal the single-cell flat panel with support frame 1, support frame 2, current guide 12, end plate 17, and edge plate 10 to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

[0089] Furthermore, the low-temperature drying temperature for screen printing AFL, YSZ, and GDC is 40℃, and the drying time is 12h.

[0090] The drying temperature of the screen printing cathode is 100℃, and the drying time is 30 minutes.

[0091] Furthermore, the temperature for multi-layer co-firing is 1280℃, and the holding time is 3 hours;

[0092] The sintering temperature for the sintering treatment was 1040℃, and the sintering time was 3h.

[0093] Further, the specific steps for wetting and smoothing are as follows: Use a lint-free cloth to wet the unscreened side of the sheet anode green blank, then attach the two sheet anode green blanks together with their respective screen-screened sides, and apply pressure to smooth the unscreened side of the two sheet anode green blanks under the action of the firing plate or other pressure device.

[0094] Furthermore, the wetting and smoothing temperature for screen printing AFL, YSZ, and GDC is 40℃, and the pressure is 0.2MPa.

[0095] Furthermore, AFL is obtained by screen printing AFL paste. By weight, AFL paste is obtained by mixing raw materials including the following components: 0.35 parts of nickel oxide powder, 0.3 parts of YSZ powder, 0.3 parts of solvent, 0.01 parts of suspending stabilizer, 0.01 parts of binder, and 0.01 parts of dispersant.

[0096] YSZ is obtained by screen printing YSZ slurry. By weight, YSZ slurry is obtained by mixing raw materials including the following components: 0.45 parts YSZ powder, 0.40 parts solvent, 0.01 parts suspending stabilizer, 0.01 parts binder, 0.02 parts dispersant, and 0.01 parts plasticizer.

[0097] GDC is obtained by screen printing GDC slurry. By weight, GDC slurry is obtained by mixing raw materials including the following components: 0.5 parts GDC powder, 0.35 parts solvent, 0.01 parts suspending stabilizer, 0.01 parts binder, and 0.02 parts dispersant.

[0098] Solvents include terpineol; suspension stabilizers include ethyl cellulose; binders include polyvinyl butyral (PVB); dispersants include triethanolamine, and in GDC slurries, dispersants include polyvinylpyrrolidone (PVP) in addition to triethanolamine; plasticizers include polyethylene glycol.

[0099] Example 4:

[0100] According to another aspect of the present invention, an embodiment of the present invention provides a method for preparing a green multilayer co-fired SOFC planar single-cell stack, comprising the following steps:

[0101] S1, Multi-layer co-firing treatment:

[0102] S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence;

[0103] S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing.

[0104] S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing.

[0105] S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell;

[0106] S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing.

[0107] S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate.

[0108] S4. Assemble and seal the single-cell flat panel with support frame 1, support frame 2, current guide 12, end plate 17, and edge plate 10 to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

[0109] Furthermore, the low-temperature drying temperature for screen printing AFL, YSZ, and GDC is 45℃, and the drying time is 11h.

[0110] The drying temperature of the screen printing cathode is 105℃, and the drying time is 25 minutes.

[0111] Furthermore, the temperature for multi-layer co-firing was 1285℃, and the holding time was 2.5h;

[0112] The sintering temperature for the sintering treatment was 1045℃, and the sintering time was 2.5h.

[0113] Further, the specific steps for wetting and smoothing are as follows: Use a lint-free cloth to wet the unscreened side of the sheet anode green blank, then attach the two sheet anode green blanks together with their respective screen-screened sides, and apply pressure to smooth the unscreened side of the two sheet anode green blanks under the action of the firing plate or other pressure device.

[0114] Furthermore, the wetting and smoothing temperature for screen printing AFL, YSZ, and GDC is 45℃, and the pressure is 0.15MPa.

[0115] Furthermore, AFL is obtained by screen printing AFL paste. By weight, AFL paste is obtained by mixing raw materials including the following components: 0.38 parts of nickel oxide powder, 0.32 parts of YSZ powder, 0.33 parts of solvent, 0.015 parts of suspending stabilizer, 0.013 parts of binder, and 0.017 parts of dispersant.

[0116] YSZ is obtained by screen printing YSZ slurry. By weight, YSZ slurry is obtained by mixing raw materials including the following components: 0.5 parts YSZ powder, 0.42 parts solvent, 0.015 parts suspending stabilizer, 0.017 parts binder, 0.03 parts dispersant, and 0.018 parts plasticizer.

[0117] GDC is obtained by screen printing GDC slurry. By weight, GDC slurry is obtained by mixing raw materials including the following components: 0.52 parts GDC powder, 0.38 parts solvent, 0.012 parts suspending stabilizer, 0.015 parts binder, and 0.025 parts dispersant.

[0118] Solvents include terpineol; suspension stabilizers include ethyl cellulose; binders include polyvinyl butyral (PVB); dispersants include triethanolamine, and in addition to triethanolamine, dispersants in GDC slurries also include polyvinylpyrrolidone (PVP) and fish oil; plasticizers include dibutyl phthalate.

[0119] Example 5:

[0120] According to another aspect of the present invention, an embodiment of the present invention provides a method for preparing a green multilayer co-fired SOFC planar single-cell stack, comprising the following steps:

[0121] S1, Multi-layer co-firing treatment:

[0122] S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence;

[0123] S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing.

[0124] S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing.

[0125] S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell;

[0126] S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing.

[0127] S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate.

[0128] S4. Assemble and seal the single-cell flat panel with support frame 1, support frame 2, current guide 12, end plate 17, and edge plate 10 to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

[0129] Furthermore, the low-temperature drying temperature for screen printing AFL, YSZ, and GDC is 50℃, and the drying time is 10h.

[0130] The drying temperature of the screen printing cathode is 110℃, and the drying time is 20 minutes.

[0131] Furthermore, the temperature for multi-layer co-firing was 1290℃, and the holding time was 2 hours;

[0132] The sintering temperature for the sintering treatment was 1050℃, and the sintering time was 2 hours.

[0133] Further, the specific steps for wetting and smoothing are as follows: Use a lint-free cloth to wet the unscreened side of the sheet anode green blank, then attach the two sheet anode green blanks together with their respective screen-screened sides, and apply pressure to smooth the unscreened side of the two sheet anode green blanks under the action of the firing plate or other pressure device.

[0134] Furthermore, the wetting and smoothing temperature for screen printing AFL, YSZ, and GDC is 50℃, and the pressure is 0.1MPa.

[0135] Furthermore, AFL is obtained by screen printing AFL paste. By weight, AFL paste is obtained by mixing raw materials including the following components: 0.40 parts of nickel oxide powder, 0.35 parts of YSZ powder, 0.35 parts of solvent, 0.02 parts of suspending stabilizer, 0.02 parts of binder, and 0.02 parts of dispersant.

[0136] YSZ is obtained by screen printing YSZ paste. By weight, YSZ paste is obtained by mixing raw materials including the following components: 0.55 parts YSZ powder, 0.45 parts solvent, 0.02 parts suspending stabilizer, 0.02 parts binder, 0.04 parts dispersant, and 0.02 parts plasticizer.

[0137] GDC is obtained by screen printing GDC slurry. By weight, GDC slurry is obtained by mixing raw materials including the following components: 0.55 parts GDC powder, 0.40 parts solvent, 0.02 parts suspending stabilizer, 0.02 parts binder, and 0.03 parts dispersant.

[0138] Solvents include terpineol; suspension stabilizers include ethyl cellulose; binders include polyvinyl butyral (PVB); dispersants include triethanolamine, and in addition to triethanolamine, dispersants in GDC slurries also include polyvinylpyrrolidone (PVP), fish oil and furoic acid; plasticizers include polyethylene glycol and dibutyl phthalate.

[0139] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a green multilayer co-fired SOFC planar single-cell stack, characterized in that, A flat single-cell stack structure of SOFC with multiple layers of green blank co-fired is adopted. The structure includes a support frame one (1) and a support frame two (2), and a single-cell assembly of sheet type that is engaged between the support frame one (1) and the support frame two (2). Both sides of the first support frame (1) are provided with mortises (4), and both sides of the second support frame (2) are provided with tenons (3). The tenons (3) and mortises (4) are engaged. The adjacent sides of the first support frame (1) and the second support frame (2) are connected by tenons (3) and mortises (4). Several return cavities (5) are provided at equal intervals on the inward side of the first support frame (1) and the second support frame (2). The single-cell assembly includes a flow guide (12). The top end of the flow guide (12) is provided with a plurality of oxidant flow channels (13) arranged laterally, and the bottom end of the flow guide (12) is provided with a plurality of fuel flow channels (14) arranged longitudinally. A return hole (15) is provided between two adjacent oxidant flow channels (13) and between two adjacent fuel flow channels (14). A single-cell assembly (16) is provided at both the top and bottom ends of the flow guide (12). An end plate (17) is stacked on the outer side of the single-cell assembly (16). A plurality of fuel flow channels (14) are arranged longitudinally at equal intervals at the bottom end of the upper end plate (17), and a plurality of oxidant flow channels (13) are arranged laterally at equal intervals at the top end of the lower end plate (17). The two sides of the oxidant flow channels (13) and the fuel flow channels (14) are respectively provided with return chambers (5) in their respective directions. The preparation method includes the following steps: S1, Multi-layer co-firing treatment: S101, Screen Printing AFL: Prepare sheet anode green blank raw material and screen print AFL on its surface, then perform low-temperature drying, wetting and smoothing and natural drying in sequence; S102, Screen Printing YSZ: Screen printing YSZ onto the AFL surface of the dried sheet anode green blank obtained in step S101, followed by low-temperature drying and wetting smoothing. S103, Screen Printing GDC: Screen printing GDC on the YSZ surface of the sheet anode green blank obtained in step S102, followed by low-temperature drying and wetting smoothing. S104. Perform multi-layer co-firing on the product processed in step S103 to obtain a half cell; S2, screen-printed cathode: The GDC surface of the obtained half cell is screen-printed with a cathode, and then dried after screen printing. S3. The half-cell with the screen-printed cathode completed in step S2 is sintered to obtain a single-cell plate. S4. Assemble and seal the single-cell flat panel with support frame one (1), support frame two (2), flow guide (12), end plate (17), and pressure plate (10) to obtain a green multilayer co-fired SOFC flat panel single-cell stack.

2. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The top and bottom left and right sides of the support frame one (1) and support frame two (2) are provided with keyholes (6), and each keyhole (6) is fitted with a locking post (9). The top of the locking post (9) is fixedly installed at the four corners of the bottom of the pressure plate (10), and the inner wall of the pressure plate (10) is fixedly installed with a pressure end strip (11).

3. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The first support frame (1) includes two support frames (1) arranged opposite to each other, and the second support frame (2) includes two support frames (2) arranged opposite to each other. An oxidant inlet (8) is fixedly installed on the outward side of one of the support frames (1), and a fuel inlet (7) is fixedly installed on the outward side of one of the support frames (2). The fuel inlet (7) and the oxidant inlet (8) are respectively connected to their respective return chambers (5). The fuel inlet (7) and oxidant inlet (8) are provided with seals, and gas sealing materials are provided on both the oxidant flow path and the fuel flow path to prevent gas leakage and mixing.

4. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The low-temperature drying temperature for screen printing AFL, YSZ, and GDC is 40-50℃, and the drying time is 10-12h. The drying temperature of the screen-printed cathode is 100-110℃, and the drying time is 20-30 minutes.

5. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The specific steps for wetting and smoothing are as follows: Moisten the unscreened side of the sheet anode blank with a lint-free cloth, then attach the two sheet anode blanks together with their respective screened sides, and apply pressure to the unscreened side of the two sheet anode blanks under the action of a firing plate or other pressure device.

6. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The wetting and smoothing temperature for the screen printing AFL, YSZ, and GDC is 40-50℃, and the pressure is 0.1-0.2MPa.

7. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The temperature of the multi-layer co-firing treatment is 1280-1290℃, and the holding time is 2-3 hours; The sintering temperature for the sintering treatment is 1040-1050℃, and the sintering time is 2-3h.

8. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 1, characterized in that, The AFL is obtained by screen printing with AFL paste. By weight, the AFL paste is obtained by mixing raw materials including the following components: 0.35-0.40 parts of nickel oxide powder, 0.3-0.35 parts of YSZ powder, 0.3-0.35 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, and 0.01-0.02 parts of dispersant. The YSZ is obtained by screen printing YSZ slurry. By weight, the YSZ slurry is obtained by mixing raw materials including the following components: 0.45-0.55 parts of YSZ powder, 0.40-0.45 parts of solvent, 0.01-0.02 parts of suspending stabilizer, 0.01-0.02 parts of binder, 0.02-0.04 parts of dispersant, and 0.01-0.02 parts of plasticizer. The GDC is obtained by screen printing GDC slurry. By weight, the GDC slurry is obtained by mixing raw materials including the following components: 0.5-0.55 parts GDC powder, 0.35-0.40 parts solvent, 0.01-0.02 parts suspending stabilizer, 0.01-0.02 parts binder, and 0.02-0.03 parts dispersant.

9. The method for preparing a green multilayer co-fired SOFC planar single-cell stack according to claim 8, characterized in that, The solvent includes terpineol; the suspension stabilizer includes ethyl cellulose; the binder includes polyvinyl butyral; the dispersant includes triethanolamine, and the dispersant in the GDC slurry includes, in addition to triethanolamine, one or more of polyvinylpyrrolidone, fish oil, and furoic acid; the plasticizer includes polyethylene glycol and / or dibutyl phthalate.

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