A carbon-resistant, self-sealing, electrically symbiotic solid oxide fuel cell structure

Abstract

This invention provides a self-sealing, anti-carbon-deposit, electrically symbiotic solid oxide fuel cell structure, relating to the field of battery technology. The battery structure includes a connecting weight reforming plate, an anode, an electrolyte, and a cathode. The connecting weight reforming plate includes a connecting body, with a battery support porous region and an oxidation gas flow channel respectively on its upper and lower surfaces. The lower surface of the battery support porous region has a reforming and reforming gas flow channel, and a reforming porous region is located between the reforming and reforming gas flow channel and the oxidation gas flow channel. The reforming porous region is separated from the upper and lower flow channels by a leak-free wall. The anode, electrolyte, and cathode are sequentially stacked on the upper surface of the battery support porous region. This battery structure achieves self-sealing of the reformed fuel and reformed gas, reducing the sealing difficulty of planar SOFCs. The indirect reforming of the fuel in the reforming porous region avoids excessive local thermal stress during internal reforming, which could cause battery structural damage and anode carbon deposition, significantly improving battery performance and service life.

Description

Technical Field

[0001] This invention relates to the field of battery technology, and more specifically, to a structure for a carbon-resistant, self-sealing, electrically symbiotic solid oxide fuel cell. Background Technology

[0002] Solid oxide fuel cells (SOFCs) are power generation devices that directly convert the chemical energy of fuel into electrical energy. They mainly consist of an anode, an electrolyte, and a cathode. The most common SOFC stack configurations are planar and tubular. Planar stacks have the advantages of simple structure, easy modular assembly, and, most importantly, a shorter current conduction path, resulting in higher power density. However, planar SOFC stacks have always suffered from disadvantages such as a large area requiring sealing, difficulty in sealing at high temperatures, and mismatch in thermal expansion between materials of various components.

[0003] Compared to other types of fuel cells, SOFCs use a wider range of fuels, including not only hydrogen but also methane, syngas, ethanol, and other hydrocarbon fuels. When using hydrocarbons as SOFC fuel, the fuel typically needs to be reformed to obtain syngas, a mixture of CO and H2, which then enters the porous electrode to undergo an electrochemical reaction. From the perspective of the reforming process, fuel reforming can be divided into external reforming and internal reforming. External reforming involves first generating syngas from the hydrocarbon fuel and then introducing it into the SOFC stack. This reforming method increases the system's size and complexity, thus increasing costs. Internal reforming involves adding a suitable amount of water vapor to the hydrocarbon fuel, utilizing the high-temperature operating environment of the SOFC to achieve internal reforming of the fuel. Although this can reduce the complexity and cost of external reforming equipment, internal fuel reforming, which occurs inside the cell, is a very fast, strongly endothermic chemical reaction that requires the absorption of a large amount of heat. This results in a large temperature gradient inside the cell, and the resulting thermal stress can easily damage the cell structure and lead to performance degradation. Furthermore, hydrocarbon fuels are highly susceptible to cracking during reforming inside the high-temperature anode, resulting in carbon deposits that coat the surface of the anode active sites, significantly degrading battery performance. Additionally, directly heating the fuel, preheating the stack with oxidizing gases to raise the temperature, or increasing the oxidizing gas flow rate to lower the stack's excessively high operating temperature can lead to structural damage, such as separation of heterogeneous interfaces within the battery, by directly exposing the preheating or cooling gases to the cathode or anode surfaces.

[0004] Therefore, sealing of flat-plate SOFC battery structures and carbon buildup in hydrocarbon fuel reforming are challenges in this field. Successfully solving these challenges would greatly advance the development and engineering application of SOFC technology.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a self-sealing electro-co-existing solid oxide fuel cell structure with anti-carbon deposits, which can achieve self-sealing of reformed fuel and reformed gas, reducing the sealing difficulty of flat SOFCs; wherein the reformed fuel in the reforming porous region can indirectly reform the reformed fuel, avoiding the battery structure damage and anode carbon deposit problems caused by excessive local thermal stress in the internal reforming, thus greatly improving battery performance and service life.

[0007] This application can be implemented as follows:

[0008] This application provides a carbon-resistant, self-sealing, electrically symbiotic solid oxide fuel cell structure, which includes a connecting weight rebalancing plate, an anode, an electrolyte, and a cathode;

[0009] The connecting reforming plate includes a connecting body. The upper and lower surfaces of the connecting body are respectively provided with a battery support porous area and an oxidation gas flow channel. The lower surface of the battery support porous area is provided with a reforming reforming gas flow channel. A reforming porous area for catalytic reaction of reformed fuel is provided between the reforming reforming gas flow channel and the oxidation gas flow channel. The reforming porous area is separated from the reforming reforming gas flow channel and the oxidation gas flow channel by a leak-free wall to achieve self-sealing of the reformed fuel.

[0010] The anode, electrolyte, and cathode are stacked sequentially on the upper surface of the porous region supporting the battery.

[0011] In an optional embodiment, the connector body is provided with at least one pair of through holes for the flow of at least one of hydrocarbon fuel, recombination gas and oxidizing gas.

[0012] In an optional embodiment, the area of ​​the battery support porous region is smaller than the area of ​​the upper surface of the connector body, and the battery support porous region is connected to the recombination syngas flow channel to allow the syngas to diffuse through the pores of the battery support porous region to the anode located on the upper surface of the battery support porous region.

[0013] In an optional implementation, the reformed porous region is a region having a polyhedral lattice unit structure.

[0014] In an optional embodiment, the porous region includes at least two porous sub-regions, adjacent porous sub-regions are separated by ribs, and multiple porous sub-regions are arranged sequentially along a direction perpendicular to the reforming fuel flow direction.

[0015] In an optional implementation, the porosity of each porous region gradually decreases along the reformed fuel flow direction.

[0016] In an optional implementation, the porosity decreases in a gradient.

[0017] In an optional implementation, the porosity is such that the maximum porosity does not exceed 90% and the minimum porosity is not less than 50%.

[0018] In an optional embodiment, all surfaces in contact with the reformed fuel are provided with a catalyst for the reforming reaction of the hydrocarbon fuel.

[0019] In an optional implementation, the thickness of the reformed porous region is 0.5-2.0 mm.

[0020] In an optional embodiment, the minimum distance between the reforming porous zone and the top of the oxidation gas flow channel or the bottom of the reforming synthesis gas flow channel is 0.5-1.0 mm.

[0021] In an optional embodiment, the anode and electrolyte respectively cover the porous area of ​​the battery support and the upper surface of the entire connecting weight remodeling plate, and the projection of the cathode coincides with the area occupied by the remodeling airflow channel.

[0022] The beneficial effects of this application include:

[0023] The battery structure of this application includes a connecting reforming plate comprising a connecting body, the upper and lower surfaces of which are respectively provided with a battery support porous region and an oxidation gas flow channel. The lower surface of the battery support porous region is provided with a reforming reforming gas flow channel. A reforming porous region for catalytic reaction of reforming fuel is provided between the reforming reforming gas flow channel and the oxidation gas flow channel. The reforming porous region is separated from the reforming reforming gas flow channel and the oxidation gas flow channel by a leak-free wall to achieve sealing of the reforming fuel. The anode, electrolyte and cathode are stacked sequentially on the upper surface of the battery support porous region.

[0024] The above settings enable self-sealing of reformed fuel and reformed gas, reducing the sealing difficulty of flat SOFCs. Furthermore, the indirect reforming of reformed fuel in the porous reforming zone avoids excessive local thermal stress during internal reforming, which can cause battery structure damage and anode carbon buildup, thus significantly improving battery performance and service life. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 A schematic diagram of the anti-carbon-deposit self-sealing electrical symbiosis solid oxide fuel cell structure provided in this application;

[0027] Figure 2 for Figure 1 Cross-sectional view along direction 1-1;

[0028] Figure 3 for Figure 2 Enlarged view of point A in the middle;

[0029] Figure 4 for Figure 3 Enlarged view of point B in the middle;

[0030] Figure 5 for Figure 1 A schematic diagram of the structure of the connecting weight-integrating plate.

[0031] Icons: 10-Connector weight reforming plate; 11-Connector body; 111-First side; 112-Second side; 113-Third side; 114-Fourth side; 115-Reformation gas inlet; 116-Reformation gas outlet; 117-Oxidation gas inlet; 118-Oxidation gas outlet; 119-Reformation fuel inlet; 120-Reformation fuel outlet; 12-Porous area of ​​battery support; 13-Reformation gas flow channel; 14-Reformation porous area; 15-Oxidation gas flow channel; 20-Anode; 30-Electrolyte; 40-Cathode. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," or "outer" are used to indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed, they are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0036] Furthermore, the terms "first" and "second" are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0037] It should be noted that, where there is no conflict, the features in the embodiments of the present invention can be combined with each other.

[0038] Example

[0039] Please refer to this as well. Figures 1 to 5 This embodiment provides a carbon-resistant, self-sealing, electrically symbiotic solid oxide fuel cell structure, which includes a connecting weight rebalancing plate 10, an anode 20, an electrolyte 30, and a cathode 40.

[0040] The connecting reforming plate 10 includes a connecting body 11. The upper and lower surfaces of the connecting body 11 are respectively provided with a battery support porous region 12 and an oxidation gas flow channel 15. The lower surface of the battery support porous region 12 is provided with a reforming reforming gas flow channel 13. A reforming porous region 14 for catalytic reaction of reformed fuel is provided between the reforming reforming gas flow channel 13 and the oxidation gas flow channel 15. The reforming porous region 14 is separated from the reforming reforming gas flow channel 13 and the oxidation gas flow channel 15 by a leak-free wall to achieve sealing of the reformed fuel.

[0041] Anode 20, electrolyte 30 and cathode 40 are stacked sequentially on the upper surface of the porous region 12 supporting the battery.

[0042] The area of ​​the aforementioned battery support porous region 12 is smaller than the area of ​​the upper surface of the connector body 11 (to avoid air leakage). The battery support porous region 12 is connected to the recombination syngas flow channel 13 to allow the syngas to diffuse through the pores of the battery support porous region 12 to the anode 20 located on the upper surface of the battery support porous region 12.

[0043] Anode 20, electrolyte 30 and cathode 40 are stacked sequentially on the upper surface of the porous region 12 supporting the battery.

[0044] The anode 20 covers the upper surface of the porous region 12 supporting the battery, while the electrolyte 30 covers the entire connecting weight remodeling plate 10 and the upper surface of the anode 20. The projection of the cathode 40 coincides with the area occupied by the remodeling gas flow channel 13.

[0045] In this application, the reformed porous region 14 is a region with a polyhedral lattice unit structure. For example, the polyhedron can be a hexahedron or an octahedron.

[0046] In some embodiments, the number of reformed porous regions 14 may be only one. In other embodiments, the reformed porous region 14 includes at least two porous sub-regions. For example, the porous region may be formed by two, three, four, five or more porous sub-regions.

[0047] When the reforming porous region 14 includes at least two porous sub-regions, adjacent porous sub-regions are separated by ribs, and multiple porous sub-regions are arranged sequentially along the direction perpendicular to the reforming fuel flow.

[0048] In this application, the porosity of each porous sub-region gradually decreases along the reformed fuel flow direction, preferably in a gradient decrease.

[0049] It should be noted that the internal reforming of fuel within the battery is a very fast, strongly endothermic chemical reaction that requires the absorption of a large amount of heat. This application, by setting the porosity to a gradient reduction mode, helps to avoid a large temperature gradient inside the battery during the reforming process, reducing the resulting thermal stress and preventing damage to the battery structure. Furthermore, this method not only prevents carbon deposits formed from hydrocarbon fuels from covering the surface of the anode 20 active sites, thus avoiding a significant decrease in battery performance, but also prevents structural damage such as separation of heterogeneous interfaces inside the battery.

[0050] For reference, among the porosities mentioned above, the maximum porosity shall not exceed 90%, and the minimum porosity shall not be less than 50%. The porosity gradient settings may involve gradients of 1%, 2%, 5%, 10%, 15%, 20%, 25%, or 30%, etc.

[0051] It should be noted that if the minimum porosity of the reforming porous region 14 is less than 50%, a large pressure drop in hydrocarbon fuel flow is likely to occur in the porous region, increasing the energy loss of the fuel pump; if the maximum porosity is greater than 90%, the area of ​​the reforming reaction region will be reduced, resulting in incomplete hydrocarbon fuel reforming reaction.

[0052] The pore size of each pore in the aforementioned reforming porous region 14 can be 50-1000μm, such as 50μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm or 1000μm, or any other value within the range of 50-1000μm.

[0053] It should be noted that if the pore size of each pore in the reforming porous region 14 is less than 50 μm, it increases the flow resistance of fuel gas and is not conducive to reducing pressure loss; if it is greater than 1000 μm, it will not only reduce the area of ​​the reforming reaction region, but also increase the thickness of the connecting body.

[0054] For reference, the total thickness of the reformed porous region 14 can be 0.5-2.0 mm, such as 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm or 2.0 mm, or any other value within the range of 0.5-2.0 mm.

[0055] If the total thickness of the reforming porous region 14 is less than 0.5 mm, it is not conducive to providing sufficient reforming reaction space, resulting in incomplete reforming reaction; if it is greater than 2.0 mm, it is not conducive to reducing the thickness of individual cells, resulting in increased stack volume and weight, and reduced stack energy density.

[0056] For ease of understanding, the recombination gas flow channel 13 can be a groove that is recessed from top to bottom. Similarly, the oxidation gas flow channel 15 can be a groove that is recessed from the lower surface of the connector body 11.

[0057] The minimum distance between the bottom of the reforming porous zone 14 and the top of the oxidation gas flow channel 15, or between the top of the reforming porous zone 14 and the bottom of the reforming synthesis gas flow channel 13, can be set to 0.5-1.0 mm, such as 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1.0 mm, or any other value within the range of 0.5-1.0 mm.

[0058] If the minimum distance between the bottom of the reforming porous region 14 and the top of the oxidation gas flow channel 15, or between the top of the reforming porous region 14 and the bottom of the reforming synthesis gas flow channel 13, is less than 0.5 mm, gas leakage and cross-contamination are likely to occur due to high-temperature corrosion of the wall surface, causing premature failure of the fuel cell stack. If the minimum distance between the bottom of the reforming porous region 14 and the top of the oxidation gas flow channel 15, or between the top of the reforming porous region 14 and the bottom of the reforming synthesis gas flow channel 13, is greater than 1.0 mm, the fuel cell stack will have a large volume and weight and a low energy density.

[0059] Preferably, all surfaces in contact with the reformed fuel are provided with a catalyst for the reforming reaction of the hydrocarbon fuel. Alternatively, only certain parts of the surfaces in contact with the reformed fuel may be provided with a catalyst for the reforming reaction of the hydrocarbon fuel.

[0060] For reference, the catalyst can be generated in situ through the design of the linker material, or it can be loaded onto the surface of the porous region 14 by methods such as impregnation.

[0061] The catalyst described above can be a material with high catalytic activity, and can include, by example but not by limitation, at least one of Al2O3, NiO, CeO2 and La2O3.

[0062] In this application, the connector body 11 is provided with at least one pair of through holes for the flow of at least one of hydrocarbon fuel, recombination gas and oxidizing gas.

[0063] In some specific embodiments, the connector body 11 and the through hole can be configured as follows:

[0064] Taking the overall quadrilateral shape (such as a rectangle) of the connecting body 11 as an example, it has a first side 111, a second side 112, a third side 113 and a fourth side 114 connected from end to end. The first side 111 and the third side 113 are arranged opposite each other, and the second side 112 and the fourth side 114 are arranged opposite each other.

[0065] The through-hole includes a reforming gas inlet 115, a reforming gas outlet 116, an oxidizing gas inlet 117, an oxidizing gas outlet 118, a reforming fuel inlet 119, and a reforming fuel outlet 120.

[0066] The reforming gas inlet 115 is located near the first side 111 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11; the reforming gas outlet 116 is located near the third side 113 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11; the oxidation gas inlet 117 is located near the third side 113 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11; the oxidation gas outlet 118 is located near the first side 111 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11; the reforming fuel inlet 119 is located near the second side 112 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11; and the reforming fuel outlet 120 is located near the fourth side 114 of the connecting body 11 and penetrates the upper and lower surfaces of the connecting body 11.

[0067] The two ends of the reforming gas flow channel 13 are connected to the reforming gas inlet 115 and the reforming gas outlet 116, respectively. The two ends of the oxidation gas flow channel 15 are connected to the oxidation gas inlet 117 and the oxidation gas outlet 118, respectively. The two ends of the reforming porous region 14 are connected to the reforming fuel inlet 119 and the reforming fuel outlet 120, respectively.

[0068] For example, the recombination gas flow channel 13 can be formed by multiple spaced recombination gas sub-channels, and the extension direction of each recombination gas sub-channel is the flow direction of the recombination gas, specifically extending from the first side 111 to the third side 113. Similarly, the oxidation gas flow channel 15 can also be formed by multiple spaced oxidation gas sub-channels, and the extension direction of each oxidation gas sub-channel is the flow direction of the oxidation gas, specifically extending from the third side 113 to the first side 111.

[0069] In some embodiments, there may be one recombination gas inlet 115 and one recombination gas outlet 116. One end of each recombination gas sub-channel is connected to the recombination gas inlet 115, and the other end is connected to the recombination gas outlet 116. In other embodiments, there may be two recombination gas inlets 115 and one recombination gas outlet 116. In this case, one end of some recombination gas sub-channels is connected to one of the recombination gas inlets 115, and one end of the remaining recombination gas sub-channels is connected to the remaining recombination gas inlet 115. The other end of all recombination gas sub-channels is connected to the recombination gas outlet 116. In other embodiments, the number of recombination gas inlets 115 and recombination gas outlets 116 can be adjusted as needed, and their specific locations on the connector body 11 can also be configured accordingly.

[0070] Similarly, in some embodiments, there may be one oxidizing gas inlet 117 and one oxidizing gas outlet 118. One end of each oxidizing gas sub-channel is connected to the oxidizing gas inlet 117, and the other end is connected to the oxidizing gas outlet 118. In other embodiments, there may be two oxidizing gas inlets 117 and one oxidizing gas outlet 118. In this case, one end of some oxidizing gas sub-channels is connected to one of the oxidizing gas inlets 117, one end of the remaining oxidizing gas sub-channels is connected to the remaining oxidizing gas inlet 117, and the other end of all oxidizing gas sub-channels is connected to the oxidizing gas outlet 118. In other embodiments, the number of oxidizing gas inlets 117 and oxidizing gas outlets 118 can be adjusted as needed, and their specific locations on the connector body 11 can also be set accordingly.

[0071] Similarly, the number of reforming fuel inlets 119 and reforming fuel outlets 120 can also be set in the manner described above. Preferably, the number of reforming fuel inlets 119 and reforming fuel outlets 120 is equal, and can be set to 1, 2 or more. More preferably, the number of reforming fuel inlets 119 and reforming fuel outlets 120 is equal to the number of porous regions and is set in a one-to-one correspondence.

[0072] It should be noted that in other embodiments, the shape of the connector body 11, as well as the location and number of through holes, can be adjusted according to actual needs. Furthermore, other aspects of solid fuel cells not detailed in this application can be found in the relevant prior art, and will not be elaborated upon here.

[0073] In summary, the battery structure provided by this application achieves self-sealing of reformed fuel and reformed gas, reducing the sealing difficulty of flat SOFC; in particular, the indirect reforming of reformed fuel in the reformed porous region 14 can avoid the battery structure damage and anode carbon deposition problems caused by excessive local thermal stress during internal reforming, thus significantly improving battery performance and service life.

[0074] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A self-sealing, anti-carbon-depositing, electrical coexisting solid oxide fuel cell structure, characterized by, The reforming plate comprises a reforming plate body, an anode, an electrolyte and a cathode. The reforming plate body comprises an upper surface and a lower surface, and the upper surface and the lower surface are respectively provided with a battery support porous area and an oxidation gas flow channel. The anode, the electrolyte and the cathode are sequentially stacked on the upper surface of the battery support porous area. The reforming porous area is a region with a polyhedral lattice unit structure. Each of the porous sub-areas has a porosity gradient decreasing along the reforming fuel flow direction. The maximum porosity is not more than 90%, and the minimum porosity is not less than 50%.

2. The self-coking, self-sealing, electrical coexisting solid oxide fuel cell structure of claim 1, wherein, The diameter of each hole in the reforming porous area is 50-1000 μm.

3. The self-coking, self-sealing, electrical coexisting solid oxide fuel cell structure of claim 1, wherein, The thickness of the reforming porous area is 0.5-2.0 mm.

4. The carbon deposition resistant self-sealing electrical symbiotic solid oxide fuel cell structure of claim 1 wherein, The minimum distance between the reforming porous area and the top of the oxidation gas flow channel or the bottom of the reforming synthesis gas flow channel is 0.5-1.0 mm.

5. The self-coking, self-sealing, electrically coexisting solid oxide fuel cell structure of any of claims 1-4, wherein, The reforming plate body is provided with at least one pair of through holes for the flow of at least one of the hydrocarbon fuel, the reforming synthesis gas and the oxidation gas. The area of the battery support porous area is smaller than the area of the upper surface of the reforming plate body. All surfaces in contact with the reforming fuel are provided with a catalyst for the reforming reaction of the hydrocarbon fuel. The anode and the electrolyte cover the upper surface of the battery support porous area and the entire reforming plate, respectively. The projection of the cathode coincides with the area occupied by the reforming synthesis gas flow channel.

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