Cathode current collector of flat tube type solid oxide fuel cell and preparation method of cathode current collector

Abstract

The invention provides a cathode current collector of a flat tube type solid oxide fuel cell and a preparation method thereof, and the preparation method of the cathode current collector of the flat tube type solid oxide fuel cell comprises the following steps: mixing cobaltic oxide, lanthanum oxide and copper oxide to obtain current collector powder; and depositing the current collector powder on the surface of a battery cathode through a plasma spraying technology to obtain the cathode current collector.

Description

Technical Field

[0001] The present invention relates to the technical field of solid oxide fuel cells, and in particular to a method for preparing a cathode current collector of a flat tube type solid oxide fuel cell and a cathode current collector of a flat tube type solid oxide fuel cell. Background Art

[0002] In the related art, flat tube solid oxide fuel cells use Ag, Pt, Au sheets or Ag, Pt, Au slurries as current collector materials. This design method, on the one hand, has high preparation costs; on the other hand, sintering is required during the preparation process, and it is difficult to control the density of the cathode current collector. Summary of the invention

[0003] In order to solve or improve at least one of the above technical problems, an object of the present invention is to provide a method for preparing a cathode current collector of a flat tube solid oxide fuel cell.

[0004] Another object of the present invention is to provide a cathode current collector for a flat tube solid oxide fuel cell.

[0005] To achieve the above objectives, the first aspect of the present invention provides a method for preparing a cathode current collector of a flat tube solid oxide fuel cell, comprising: mixing cobalt trioxide, lanthanum oxide and copper oxide to obtain a current collector powder; depositing the current collector powder on the surface of the battery cathode by plasma spraying technology to obtain a cathode current collector.

[0006] According to the technical solution of the method for preparing the cathode current collector of the flat tube solid oxide fuel cell provided by the present invention, on the first aspect, the preparation method is simple; on the second aspect, no expensive materials such as silver, platinum, gold, etc. are required, which is conducive to reducing costs; on the third aspect, no sintering is required during the preparation process, and the density and conductivity of the prepared cathode current collector are relatively high.

[0007] Solid Oxide Fuel Cell (SOFC) belongs to the third generation of fuel cells. It is an all-solid-state chemical power generation device that can efficiently convert the chemical energy stored in fuel and oxidant into electrical energy at medium and high temperatures.

[0008] Solid oxide fuel cells mainly include: electrolyte, anode or fuel electrode, cathode or air electrode, interconnect or bipolar separator. The working principle of solid oxide fuel cells is similar to that of other fuel cells, which is equivalent to the "reverse" device of water electrolysis in principle. Its single cell is composed of anode, cathode and solid oxide electrolyte. The anode is the place where the fuel is oxidized, and the cathode is the place where the oxidant is reduced. Both electrodes contain catalysts that accelerate the electrochemical reaction of the electrodes. When working, it is equivalent to a DC power supply, with the anode as the negative pole of the power supply and the cathode as the positive pole of the power supply.

[0009] Fuel gas, such as hydrogen (H2), methane (CH4), city gas, etc., is continuously introduced into the anode side of the solid oxide fuel cell. The catalytic anode surface absorbs the fuel gas and diffuses to the interface between the anode and the electrolyte through the porous structure of the anode. Oxygen or air is continuously introduced into the cathode side. The porous cathode surface absorbs oxygen and obtains O due to the catalytic effect of the cathode itself. 2- , under the action of chemical potential, O 2- The electrons enter the solid oxygen ion conductor that acts as an electrolyte, diffuse due to the concentration gradient, and eventually reach the interface between the solid electrolyte and the anode, react with the fuel gas, and the lost electrons return to the cathode through the external circuit.

[0010] A single cell can only generate a voltage of about 1V, and its power is limited. In order to make SOFC have practical applications, the power of SOFC needs to be greatly improved. To this end, several single cells can be assembled into a battery pack in various ways (series, parallel, hybrid). The structure of the battery pack mainly includes: tubular, planar and unique. Among them, the planar type has become the development trend of SOFC due to its high power density and low production cost.

[0011] Specifically, the method for preparing the cathode current collector of the flat tube solid oxide fuel cell comprises the following steps:

[0012] The first step is to mix cobalt trioxide, lanthanum oxide and copper oxide to obtain a current collector powder. Cobalt trioxide is an inorganic compound with the chemical formula Co2O3, which is a black oxide of cobalt. Lanthanum oxide is an inorganic compound with the chemical formula LaO. Copper oxide is an inorganic substance with the chemical formula CuO, which is a black oxide of copper. After the three oxides are mixed, they are deposited on the surface of the battery cathode through plasma spraying technology, producing the following reaction to form LaCo x Cu (1-x) O3。

[0013] LaO+(1-x)CuO+1 / 2xCo2O3→2LaCo x Cu (1-x) O3, x=0~1.

[0014] The current collector refers to a structure or part that collects current. Its main function is to collect the current generated by the active materials of the battery so as to form a larger current for external output. Optionally, the mass fraction of cobalt trioxide in the current collector powder is 70% to 80%; the mass fraction of lanthanum oxide in the current collector powder is 5% to 10%; the mass fraction of copper oxide in the current collector powder is 10% to 20%. The purpose of this step is to obtain the current collector powder after mixing the three raw materials;

[0015] In the second step, the current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain a cathode current collector. The current collector powder is subjected to high temperature treatment by a plasma torch. The plasma torch has a plasma flame. The plasma flame has an ultra-high temperature (the center temperature exceeds 10,000°C). The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain a cathode current collector. Optionally, the voltage of the plasma torch is 70V to 90V; the current of the plasma torch is 450A to 700A. Optionally, the current collector powder is sprayed to the plasma flame of the plasma torch under the atmosphere of a protective gas and an auxiliary gas. Optionally, the protective gas is argon and / or nitrogen; the auxiliary gas is oxygen. Optionally, the powder feeding speed of the current collector powder is 50mg / min; the powder feeding pressure of the current collector powder is 40MPa to 80MPa. Optionally, the spraying distance of the current collector powder is 20cm to 40cm. During the spraying process, the auxiliary gas is used to accelerate the melting of the current collector powder into droplets. The droplets can be evenly deposited on the surface of the battery cathode under the action of the protective gas purge.

[0016] In the technical solution defined in the present invention, a method for preparing a cathode current collector of a flat tube solid oxide fuel cell is provided. On the first aspect, the preparation method is simple; on the second aspect, no expensive materials such as silver, platinum, and gold are required, which is conducive to reducing costs; on the third aspect, no sintering is required during the preparation process, and the density and conductivity of the prepared cathode current collector are relatively high.

[0017] In addition, the above technical solution provided by the present invention may also have the following additional technical features:

[0018] In the above technical scheme, the current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector, specifically: the current collector powder is subjected to high-temperature treatment by a plasma torch, the current collector powder is sprayed toward the plasma flame of the plasma torch under an atmosphere of protective gas and auxiliary gas, the current collector powder is melted into droplets and then deposited on the surface of the battery cathode to obtain the cathode current collector.

[0019] In this technical solution, a plasma torch (also known as a plasma generator or plasma heating system) generates high-temperature gas through an electric arc, and can work in an oxidizing, reducing or inert environment, providing a heat source for industrial furnaces with various functions such as gasification, cracking, reaction, melting and smelting. The plasma torch has a plasma flame, and the central temperature of the plasma flame exceeds 10,000°C. The current collector powder is sprayed onto the plasma flame of the plasma torch under an atmosphere of protective gas and auxiliary gas. Optionally, the protective gas is argon and / or nitrogen; the auxiliary gas is oxygen. During the spraying process, the auxiliary gas is used to accelerate the melting of the current collector powder into droplets. The droplets can be evenly deposited on the surface of the battery cathode under the action of the protective gas purge.

[0020] In the above technical solution, the protective gas is argon.

[0021] In this technical solution, argon, as an inert gas, will not react chemically with the current collector powder to ensure the purity of the prepared cathode current collector. In addition, during the spraying process, the current collector powder is treated by the high temperature of the plasma torch and melted into droplets. The argon gas can purge the droplets so that the droplets are evenly deposited on the surface of the battery cathode.

[0022] In the above technical solution, the flow rate of argon gas is 70 L / min to 130 L / min.

[0023] In this technical solution, by controlling the flow rate of argon gas, on the one hand, it is possible to avoid the flow rate of the protective gas being too low, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector. The droplets can also be purged during the spraying process to allow the droplets to be evenly deposited on the surface of the battery cathode. On the other hand, it is possible to avoid the flow rate of the protective gas being too large, which is beneficial to controlling energy consumption.

[0024] In the above technical solution, the flow rate of argon is 100 L / min.

[0025] In this technical solution, by setting the flow rate of argon gas to 100L / min, the energy consumption will not be too high, and the protective gas has a large enough flow rate to ensure the purity of the prepared cathode current collector. The droplets can also be purged during the spraying process so that the droplets are evenly deposited on the surface of the battery cathode.

[0026] In the above technical solution, the protective gas is nitrogen.

[0027] In this technical solution, nitrogen, as an inert gas, will not react chemically with the current collector powder to ensure the purity of the prepared cathode current collector. In addition, during the spraying process, the current collector powder is treated by the high temperature of the plasma torch and melted into droplets. The nitrogen can purge the droplets so that the droplets are evenly deposited on the surface of the battery cathode.

[0028] In the above technical solution, the flow rate of nitrogen is 20L / min to 100L / min.

[0029] In this technical solution, by controlling the flow rate of nitrogen, on the one hand, it is possible to avoid the flow rate of the protective gas being too low, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector. The droplets can also be purged during the spraying process to allow the droplets to be evenly deposited on the surface of the battery cathode. On the other hand, it is possible to avoid the flow rate of the protective gas being too large, which is beneficial to controlling energy consumption.

[0030] In the above technical solution, the flow rate of nitrogen is 60L / min.

[0031] In this technical solution, by setting the nitrogen flow rate to 60L / min, the energy consumption will not be too high, and the protective gas has a large enough flow rate to ensure the purity of the prepared cathode current collector. The droplets can also be purged during the spraying process so that the droplets are evenly deposited on the surface of the battery cathode.

[0032] In the above technical solution, the auxiliary gas is oxygen.

[0033] In this technical solution, by setting the auxiliary gas to oxygen, on the one hand, it plays a role of combustion support, accelerating combustion to melt the collector powder into droplets; on the other hand, it can also control the flow direction of the fluid and play a guiding role to a certain extent.

[0034] In the above technical solution, the flow rate of oxygen is 10 L / min to 35 L / min.

[0035] In this technical solution, by controlling the flow rate of oxygen, on the one hand, the flow rate of the auxiliary gas will not be too low, ensuring the combustion-supporting effect and the guiding effect; on the other hand, the flow rate of the auxiliary gas will not be too high, which is conducive to controlling energy consumption.

[0036] In the above technical solution, the flow rate of oxygen is 20L / min.

[0037] In this technical solution, by setting the oxygen flow rate to 20L / min, the energy consumption will not be too high, and the oxygen has a large enough flow rate to ensure the combustion-supporting effect and the guiding effect.

[0038] In the above technical solution, the voltage of the plasma torch is 70V to 90V.

[0039] In this technical solution, by controlling the voltage of the plasma torch, on the one hand, the voltage of the plasma torch will not be too low, ensuring the central temperature of the plasma flame; on the other hand, the voltage of the plasma torch will not be too high, which is conducive to controlling energy consumption.

[0040] In the above technical solution, the current of the plasma torch is 450A to 700A.

[0041] In this technical solution, by controlling the current of the plasma torch, on the one hand, the current of the plasma torch will not be too low, ensuring the central temperature of the plasma flame; on the other hand, the current of the plasma torch will not be too high, which is conducive to controlling energy consumption.

[0042] In the above technical solution, the feeding speed of the current collector powder is 50 mg / min to 80 mg / min.

[0043] In this technical solution, by controlling the powder feeding speed of the current collector powder, on the one hand, the powder feeding amount of the current collector powder per unit time will not be too small, ensuring that the current collector powder can be deposited on the surface of the battery cathode through plasma spraying technology to prepare the cathode current collector; on the other hand, the powder feeding amount of the current collector powder per unit time will not be too much, avoiding material waste.

[0044] In the above technical solution, the feeding speed of the current collector powder is 65 mg / min.

[0045] In this technical solution, by setting the powder feeding speed of the current collector powder to 65 mg / min, material waste is avoided while ensuring that the powder feeding amount of the current collector powder per unit time is sufficient, so that the current collector powder can be deposited on the surface of the battery cathode through plasma spraying technology to prepare the cathode current collector.

[0046] In the above technical solution, the powder feeding pressure of the current collector powder is 40MPa to 80MPa.

[0047] In this technical solution, by controlling the powder feeding pressure of the current collector powder, it is possible to ensure that the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch, wherein the dispersion range is neither too large nor too small.

[0048] In the above technical solution, the powder feeding pressure of the current collector powder is 60 MPa.

[0049] In this technical solution, by setting the powder feeding pressure of the current collector powder to 60 MPa, the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch.

[0050] In the above technical solution, the spraying distance of the current collector powder is 20 cm to 40 cm.

[0051] In this technical solution, by controlling the spraying distance of the current collector powder, it is possible to ensure that the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch, wherein the dispersion range is neither too large nor too small.

[0052] In the above technical solution, the spraying distance is 30 cm.

[0053] In this technical solution, by setting the spraying distance of the current collector powder to 30 cm, the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch.

[0054] In the above technical solution, the mass fraction of cobalt trioxide in the current collector powder is 70% to 80%.

[0055] In this technical solution, by controlling the mass fraction of cobalt trioxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode through plasma spraying technology, thereby preparing a low-cost cathode current collector.

[0056] In the above technical solution, the mass fraction of lanthanum oxide in the current collector powder is 5% to 10%.

[0057] In this technical solution, by controlling the mass fraction of lanthanum oxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode through plasma spraying technology, thereby preparing a low-cost cathode current collector.

[0058] In the above technical solution, the mass fraction of copper oxide in the current collector powder is 10% to 20%.

[0059] In this technical solution, by controlling the mass fraction of copper oxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode through plasma spraying technology, thereby preparing a low-cost cathode current collector.

[0060] A second aspect of the present invention provides a cathode current collector for a flat tube type solid oxide fuel cell, which is manufactured by the method for preparing a cathode current collector for a flat tube type solid oxide fuel cell in any of the above technical solutions.

[0061] According to the technical solution of the cathode current collector of the flat tube solid oxide fuel cell of the present invention, the cathode current collector of the flat tube solid oxide fuel cell is manufactured by the preparation method of the cathode current collector of the flat tube solid oxide fuel cell in any of the above technical solutions. The cathode current collector has the advantages of low cost, high density and high conductivity.

[0062] Additional aspects and advantages of the technical solutions of the present invention will become apparent in the following description or will be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Figure 1 A first flow chart showing a method for preparing a cathode current collector of a flat tube solid oxide fuel cell according to an embodiment of the present invention;

[0064] Figure 2 A second schematic diagram of a method for preparing a cathode current collector of a flat tube solid oxide fuel cell according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0065] In order to more clearly understand the above-mentioned purposes, features and advantages of the embodiments of the present invention, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0066] In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the embodiments of the present invention may also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present application is not limited to the specific embodiments disclosed below.

[0067] Refer to the following Figure 1 and Figure 2 The cathode current collector of a flat tube solid oxide fuel cell and a preparation method thereof are described according to some embodiments of the present invention.

[0068] Solid Oxide Fuel Cell (SOFC) belongs to the third generation of fuel cells. It is an all-solid-state chemical power generation device that can efficiently convert the chemical energy stored in fuel and oxidant into electrical energy at medium and high temperatures.

[0069] Solid oxide fuel cells mainly include: electrolyte, anode or fuel electrode, cathode or air electrode, interconnect or bipolar separator. The working principle of solid oxide fuel cells is similar to that of other fuel cells, which is equivalent to the "reverse" device of water electrolysis in principle. Its single cell is composed of anode, cathode and solid oxide electrolyte. The anode is the place where the fuel is oxidized, and the cathode is the place where the oxidant is reduced. Both electrodes contain catalysts that accelerate the electrochemical reaction of the electrodes. When working, it is equivalent to a DC power supply, with the anode as the negative pole of the power supply and the cathode as the positive pole of the power supply.

[0070] Fuel gas, such as hydrogen (H2), methane (CH4), city gas, etc., is continuously introduced into the anode side of the solid oxide fuel cell. The catalytic anode surface absorbs the fuel gas and diffuses to the interface between the anode and the electrolyte through the porous structure of the anode. Oxygen or air is continuously introduced into the cathode side. The porous cathode surface absorbs oxygen and obtains O due to the catalytic effect of the cathode itself. 2- , under the action of chemical potential, O 2- The electrons enter the solid oxygen ion conductor that acts as an electrolyte, diffuse due to the concentration gradient, and eventually reach the interface between the solid electrolyte and the anode, react with the fuel gas, and the lost electrons return to the cathode through the external circuit.

[0071] A single cell can only generate a voltage of about 1V, and its power is limited. In order to make SOFC have practical applications, the power of SOFC needs to be greatly improved. To this end, several single cells can be assembled into a battery pack in various ways (series, parallel, hybrid). The structure of the battery pack mainly includes: tubular, planar and unique. Among them, the planar type has become the development trend of SOFC due to its high power density and low production cost.

[0072] In one embodiment according to the present invention, Figure 1 As shown, the steps of the method for preparing the cathode current collector of the flat tube solid oxide fuel cell include:

[0073] S102, mix cobalt trioxide, lanthanum oxide and copper oxide to obtain current collector powder. Cobalt trioxide is an inorganic compound with the chemical formula Co2O3, which is a black oxide of cobalt. Lanthanum oxide is an inorganic compound with the chemical formula LaO. Copper oxide is an inorganic substance with the chemical formula CuO, which is a black oxide of copper. The current collector refers to a structure or part that collects current, and its main function is to collect the current generated by the active substances of the battery in order to form a larger current for external output. Optionally, the mass fraction of cobalt trioxide in the current collector powder is 70% to 80%; the mass fraction of lanthanum oxide in the current collector powder is 5% to 10%; the mass fraction of copper oxide in the current collector powder is 10% to 20%. The purpose of this step is to obtain the current collector powder after mixing the three raw materials;

[0074] S104, depositing the current collector powder on the surface of the battery cathode by plasma spraying technology to obtain a cathode current collector. The current collector powder is subjected to high temperature treatment by a plasma torch. The plasma torch has a plasma flame. The plasma flame has an ultra-high temperature (the center temperature exceeds 10000°C). The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain a cathode current collector. Optionally, the voltage of the plasma torch is 70V to 90V; the current of the plasma torch is 450A to 700A. Optionally, the current collector powder is sprayed to the plasma flame of the plasma torch under the atmosphere of protective gas and auxiliary gas. Optionally, the protective gas is argon and / or nitrogen; the auxiliary gas is oxygen. Optionally, the powder feeding speed of the current collector powder is 50mg / min; the powder feeding pressure of the current collector powder is 40MPa to 80MPa. Optionally, the spraying distance of the current collector powder is 20cm to 40cm. During the spraying process, the auxiliary gas is used to accelerate the melting of the current collector powder into droplets. The droplets can be evenly deposited on the surface of the battery cathode under the action of the protective gas purge.

[0075] Table 1

[0076]

[0077] Table 1 is a comparison between the preparation method of the present invention and the traditional preparation method. It can be seen from Table 1 that the preparation method of the present invention does not require expensive materials such as silver, platinum, and gold compared to the traditional preparation method, and the prepared cathode current collector has higher density and conductivity.

[0078] In the technical solution defined in the present invention, a method for preparing a cathode current collector of a flat tube solid oxide fuel cell is provided. On the first aspect, the preparation method is simple; on the second aspect, no expensive materials such as silver, platinum, and gold are required, which is conducive to reducing costs; on the third aspect, no sintering is required during the preparation process, and the density and conductivity of the prepared cathode current collector are relatively high.

[0079] In one embodiment according to the present invention, Figure 2 As shown, the steps of the method for preparing the cathode current collector of the flat tube solid oxide fuel cell include:

[0080] S202, mix cobalt trioxide, lanthanum oxide and copper oxide to obtain current collector powder. Cobalt trioxide is an inorganic compound with the chemical formula Co2O3, which is a black oxide of cobalt. Lanthanum oxide is an inorganic compound with the chemical formula LaO. Copper oxide is an inorganic substance with the chemical formula CuO, which is a black oxide of copper. The current collector refers to a structure or part that collects current, and its main function is to collect the current generated by the active substances of the battery in order to form a larger current for external output. Optionally, the mass fraction of cobalt trioxide in the current collector powder is 70% to 80%; the mass fraction of lanthanum oxide in the current collector powder is 5% to 10%; the mass fraction of copper oxide in the current collector powder is 10% to 20%. The purpose of this step is to obtain the current collector powder after mixing the three raw materials;

[0081] S204, subjecting the current collector powder to high temperature treatment by a plasma torch, spraying the current collector powder onto the plasma flame of the plasma torch in an atmosphere of protective gas and auxiliary gas, and depositing the current collector powder on the surface of the battery cathode after melting into droplets to obtain a cathode current collector. A plasma torch (also known as a plasma generator or plasma heating system) generates high-temperature gas by an electric arc, and can work in an oxidizing, reducing or inert environment, providing a heat source for industrial furnaces with various functions such as gasification, cracking, reaction, melting and smelting. A plasma torch has a plasma flame. The plasma flame has an ultra-high temperature (the center temperature exceeds 10,000°C). The current collector powder is sprayed onto the plasma flame of the plasma torch in an atmosphere of protective gas and auxiliary gas. Optionally, the protective gas is argon and / or nitrogen; the auxiliary gas is oxygen. Optionally, the voltage of the plasma torch is 70V to 90V; the current of the plasma torch is 450A to 700A. Optionally, the powder feeding speed of the current collector powder is 50 mg / min; the powder feeding pressure of the current collector powder is 40 MPa to 80 MPa. Optionally, the spraying distance of the current collector powder is 20 cm to 40 cm. During the spraying process, the auxiliary gas is used to accelerate the melting of the current collector powder into droplets. The droplets can be evenly deposited on the surface of the battery cathode under the action of the protective gas purge.

[0082] In one embodiment of the present invention, the protective gas is argon. As an inert gas, argon will not react chemically with the current collector powder to ensure the purity of the prepared cathode current collector. In addition, during the spraying process, after the current collector powder is treated by the high temperature of the plasma torch and melted into droplets, the argon gas can purge the droplets so that the droplets are evenly deposited on the surface of the battery cathode.

[0083] Furthermore, the flow rate of argon gas is 70L / min to 130L / min. By controlling the flow rate of argon gas, on the one hand, the flow rate of the protective gas can be prevented from being too low, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector, and the droplets can be purged during the spraying process to make the droplets evenly deposited on the surface of the battery cathode; on the other hand, the flow rate of the protective gas can be prevented from being too large, which is conducive to controlling energy consumption.

[0084] In another embodiment, the flow rate of argon is 100 L / min. By setting the flow rate of argon to 100 L / min, the energy consumption will not be too high, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector, and the droplets can be purged during the spraying process so that the droplets are evenly deposited on the surface of the battery cathode.

[0085] In one embodiment of the present invention, the protective gas is nitrogen. As an inert gas, nitrogen will not react chemically with the current collector powder to ensure the purity of the prepared cathode current collector. In addition, during the spraying process, after the current collector powder is treated by the high temperature of the plasma torch and melted into droplets, the nitrogen can purge the droplets so that the droplets are evenly deposited on the surface of the battery cathode.

[0086] Furthermore, the flow rate of nitrogen is 20L / min to 100L / min. By controlling the flow rate of nitrogen, on the one hand, the flow rate of the protective gas can be prevented from being too low, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector, and the droplets can be purged during the spraying process to make the droplets evenly deposited on the surface of the battery cathode; on the other hand, the flow rate of the protective gas can be prevented from being too large, which is conducive to controlling energy consumption.

[0087] In another embodiment, the flow rate of nitrogen is 60 L / min. By setting the flow rate of nitrogen to 60 L / min, the energy consumption will not be too high, and the protective gas has a sufficiently large flow rate to ensure the purity of the prepared cathode current collector, and the droplets can be purged during the spraying process so that the droplets are evenly deposited on the surface of the battery cathode.

[0088] In one embodiment of the present invention, the auxiliary gas is oxygen. By setting the auxiliary gas to oxygen, on the one hand, it plays a role of combustion support, accelerating combustion to melt the collector powder into droplets; on the other hand, it can also control the flow direction of the fluid and play a guiding role to a certain extent.

[0089] Furthermore, the flow rate of oxygen is 10L / min to 35L / min. By controlling the flow rate of oxygen, on the one hand, the flow rate of the auxiliary gas will not be too low, ensuring the combustion-supporting effect and the guiding effect; on the other hand, the flow rate of the auxiliary gas will not be too high, which is conducive to controlling energy consumption.

[0090] In another embodiment, the flow rate of oxygen is 20 L / min. By setting the flow rate of oxygen to 20 L / min, the energy consumption will not be too high, and the oxygen has a sufficiently large flow rate to ensure the combustion-supporting effect and the guiding effect.

[0091] In another embodiment, the voltage of the plasma torch is 70 V to 90 V. By controlling the voltage of the plasma torch, on the one hand, the voltage of the plasma torch will not be too low, ensuring the central temperature of the plasma flame; on the other hand, the voltage of the plasma torch will not be too high, which is conducive to controlling energy consumption.

[0092] In another embodiment, the current of the plasma torch is 450 A to 700 A. By controlling the current of the plasma torch, on the one hand, the current of the plasma torch will not be too low, ensuring the central temperature of the plasma flame; on the other hand, the current of the plasma torch will not be too high, which is conducive to controlling energy consumption.

[0093] In one embodiment of the present invention, the powder feeding speed of the current collector powder is 50 mg / min to 80 mg / min. By controlling the powder feeding speed of the current collector powder, on the one hand, the powder feeding amount of the current collector powder per unit time will not be too small, ensuring that the current collector powder can be deposited on the surface of the battery cathode through the plasma spraying technology to prepare the cathode current collector; on the other hand, the powder feeding amount of the current collector powder per unit time will not be too much, avoiding material waste.

[0094] Furthermore, the powder feeding speed of the current collector powder is 65 mg / min. By setting the powder feeding speed of the current collector powder to 65 mg / min, while avoiding material waste, it is ensured that the powder feeding amount of the current collector powder per unit time is sufficient, so that the current collector powder can be deposited on the surface of the battery cathode through the plasma spraying technology to prepare the cathode current collector.

[0095] In one embodiment of the present invention, the powder feeding pressure of the current collector powder is 40MPa to 80MPa. By controlling the powder feeding pressure of the current collector powder, it is possible to ensure that the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch, wherein the dispersion range is neither too large nor too small.

[0096] Furthermore, the powder feeding pressure of the current collector powder is 60 MPa. By setting the powder feeding pressure of the current collector powder to 60 MPa, the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch.

[0097] In one embodiment of the present invention, the spraying distance of the current collector powder is 20 cm to 40 cm. By controlling the spraying distance of the current collector powder, it is possible to ensure that the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch, wherein the dispersion range is neither too large nor too small.

[0098] Furthermore, the spraying distance is 30 cm. By setting the spraying distance of the current collector powder to 30 cm, the current collector powder has an appropriate dispersion effect and dispersion range in the plasma torch.

[0099] In one embodiment of the present invention, the mass fraction of cobalt trioxide in the current collector powder is 70% to 80%. By controlling the mass fraction of cobalt trioxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode by plasma spraying technology, and a low-cost cathode current collector is prepared.

[0100] In one embodiment of the present invention, the mass fraction of lanthanum oxide in the current collector powder is 5% to 10%. By controlling the mass fraction of lanthanum oxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode by plasma spraying technology, and a low-cost cathode current collector is prepared.

[0101] In one embodiment of the present invention, the mass fraction of copper oxide in the current collector powder is 10% to 20%. By controlling the mass fraction of copper oxide in the current collector powder, it is ensured that the current collector powder is deposited on the surface of the battery cathode by plasma spraying technology, and a low-cost cathode current collector is prepared.

[0102] In one embodiment of the present invention, the cathode current collector of the flat tube solid oxide fuel cell is made by the preparation method of the cathode current collector of the flat tube solid oxide fuel cell in any of the above embodiments. The cathode current collector has the advantages of low cost, high density and high conductivity.

[0103] According to the embodiments of the cathode current collector of the flat tube solid oxide fuel cell and the preparation method thereof of the present invention, on the one hand, the preparation method is simple; on the other hand, no expensive materials such as silver, platinum, and gold are required, which is conducive to reducing costs; on the third hand, no sintering is required during the preparation process, and the density and conductivity of the prepared cathode current collector are relatively high.

[0104] Example 1

[0105] This embodiment adopts the preparation method of the present invention to prepare a cathode current collector of a flat tube solid oxide fuel cell, including the following steps:

[0106] Cobalt trioxide, lanthanum oxide and copper oxide are mixed to obtain a current collector powder, wherein the mass fraction of cobalt trioxide in the current collector powder is 70%, the mass fraction of lanthanum oxide in the current collector powder is 10%, and the mass fraction of copper oxide in the current collector powder is 20%.

[0107] The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector. The voltage of the plasma torch is 70V, the current is 450A, the protective gas is argon, and the flow rate of argon is 70L / min; the auxiliary gas is oxygen, and the flow rate of oxygen is 35L / min; the powder feeding speed of the current collector powder is 50mg / min, the powder feeding pressure is 40MPa, and the spraying distance is 20cm.

[0108] Example 2

[0109] This embodiment adopts the preparation method of the present invention to prepare a cathode current collector of a flat tube solid oxide fuel cell, including the following steps:

[0110] Cobalt trioxide, lanthanum oxide and copper oxide are mixed to obtain a current collector powder, wherein the mass fraction of cobalt trioxide in the current collector powder is 75%, the mass fraction of lanthanum oxide in the current collector powder is 10%, and the mass fraction of copper oxide in the current collector powder is 15%.

[0111] The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector. The voltage of the plasma torch is 80V, the current is 600A, the protective gas is argon, and the flow rate of argon is 100L / min; the auxiliary gas is oxygen, and the flow rate of oxygen is 20L / min; the powder feeding speed of the current collector powder is 65mg / min, the powder feeding pressure is 60MPa, and the spraying distance is 30cm.

[0112] Example 3

[0113] This embodiment adopts the preparation method of the present invention to prepare a cathode current collector of a flat tube solid oxide fuel cell, including the following steps:

[0114] Cobalt trioxide, lanthanum oxide and copper oxide are mixed to obtain a current collector powder, wherein the mass fraction of cobalt trioxide in the current collector powder is 80%, the mass fraction of lanthanum oxide in the current collector powder is 5%, and the mass fraction of copper oxide in the current collector powder is 15%.

[0115] The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector. The voltage of the plasma torch is 90V, the current is 700A, the protective gas is nitrogen, the flow rate of nitrogen is 60L / min, the auxiliary gas is oxygen, the flow rate of oxygen is 25L / min, the powder feeding speed of the current collector powder is 80mg / min, the powder feeding pressure is 80MPa, and the spraying distance is 40cm.

[0116] Comparative Example 1

[0117] This comparative example adopts a conventional preparation method to prepare a cathode current collector of a flat tube solid oxide fuel cell, comprising the following steps:

[0118] Step 1: Cobalt trioxide, lanthanum oxide, copper oxide, precious metal powder (silver powder) and polyvinyl butyral are mixed to prepare slurry A. The mass ratio of cobalt trioxide, lanthanum oxide and copper oxide is the same as that in Example 1, and the mass ratio of their total mass to silver powder is 99:1; in slurry A, the mass percentages of inorganic powder (cobalt trioxide, lanthanum oxide, copper oxide and silver powder) and polyvinyl butyral are 98% and 2%, respectively.

[0119] Step 2: Print the slurry A onto the surface of the flat battery by screen printing technology to complete the printing of the current collector C;

[0120] Step 3: Sinter the printed current collector C in a high-temperature furnace at 800°C for 5 hours to complete the current collector preparation.

[0121] The cathode current collectors prepared in the above Examples 1-3 and Comparative Example 1 were tested for performance, and the results are shown in Table 2:

[0122] Table 2

[0123]

[0124] The conductivity test adopts the four-probe method; porosity = 100% - density, density = actual density / theoretical density x 100%, and the actual density is determined by the Archimedes drainage method.

[0125] In the present invention, the terms "first", "second", and "third" are used for descriptive purposes only and should not be understood as indicating or implying relative importance; the term "plurality" refers to two or more, unless otherwise clearly defined. The terms "installed", "connected", "connected", "fixed", etc. should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral connection; "connected" can be a direct connection or an indirect connection through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0126] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by terms such as “upper”, “lower”, “left”, “right”, “front” and “back” are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or unit referred to must have a specific direction, be constructed and operated in a specific orientation, and therefore, cannot be understood as a limitation on the present invention.

[0127] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0128] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a cathode current collector for a flat tube solid oxide fuel cell, characterized in that: include: Mixing cobalt trioxide, lanthanum oxide and copper oxide to obtain a current collector powder; The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector.

2. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 1, characterized in that: The current collector powder is deposited on the surface of the battery cathode by plasma spraying technology to obtain the cathode current collector, specifically: The current collector powder is subjected to high temperature treatment by a plasma torch, and the current collector powder is sprayed onto the plasma flame of the plasma torch under an atmosphere of protective gas and auxiliary gas. The current collector powder is melted into droplets and then deposited on the surface of the battery cathode to obtain the cathode current collector.

3. The method for preparing the cathode current collector of the flat tube solid oxide fuel cell according to claim 2, characterized in that: The protective gas is argon.

4. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 3, characterized in that: The flow rate of the argon gas is 70 L / min to 130 L / min.

5. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 4, characterized in that: The flow rate of the argon gas is 100 L / min.

6. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 2, characterized in that: The protective gas is nitrogen.

7. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 6, characterized in that: The flow rate of the nitrogen gas is 20 L / min to 100 L / min.

8. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 7, characterized in that: The flow rate of the nitrogen gas is 60 L / min.

9. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 2, characterized in that: The auxiliary gas is oxygen.

10. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 9, characterized in that: The flow rate of the oxygen is 10 L / min to 35 L / min.

11. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 10, characterized in that: The flow rate of the oxygen is 20 L / min.

12. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 2, characterized in that: The voltage of the plasma torch is 70V to 90V.

13. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 2, characterized in that: The current of the plasma torch is 450A to 700A.

14. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The powder feeding speed of the current collector powder is 50 mg / min to 80 mg / min.

15. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 14, characterized in that: The feeding speed of the current collector powder is 65 mg / min.

16. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The powder feeding pressure of the current collector powder is 40 MPa to 80 MPa.

17. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 16, characterized in that: The powder feeding pressure of the current collector powder is 60 MPa.

18. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The spraying distance of the current collector powder is 20 cm to 40 cm.

19. The method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to claim 18, characterized in that: The spraying distance is 30 cm.

20. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The mass fraction of the cobalt trioxide in the current collector powder is 70% to 80%.

21. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The mass fraction of the lanthanum oxide in the current collector powder is 5% to 10%.

22. The method for preparing a cathode current collector for a flat tube solid oxide fuel cell according to any one of claims 1 to 13, characterized in that: The mass fraction of the copper oxide in the current collector powder is 10% to 20%.

23. A cathode current collector for a flat tube solid oxide fuel cell, characterized in that: The cathode current collector of a flat tube solid oxide fuel cell is manufactured by the method for preparing the cathode current collector of a flat tube solid oxide fuel cell according to any one of claims 1 to 22.

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