Metal foam-supported self-breathing solid oxide fuel cell stack

Abstract

The present invention provides a self-breathing solid oxide fuel cell stack supported by a foam metal, which can improve the mechanical strength of the battery cells and reduce the volume and cost of the solid oxide fuel cell stack; it can also promote the electrochemical reaction at the anode and increase the power density of the battery cells. The present invention provides a solid oxide fuel cell stack, comprising: a first end plate, a second end plate, and a plurality of stacked battery cells disposed between the first and second end plates, wherein the battery cells include: a bipolar plate, composed of a cathode plate and an anode plate bridged together, with a clamping structure formed between two adjacent bipolar plates; a battery cell, which is embedded in the clamping structure; and a foam metal, with the anode plate and the battery cell respectively attached to either side of the foam metal, and the cathode plate formed into a concave platform structure with multiple ventilation holes.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cells, and in particular to a self-breathing solid oxide fuel cell stack supported by foam metal. Background Art

[0002] Fuel cells are widely used energy conversion devices that not only efficiently convert the chemical energy in fuel gases (such as hydrogen, carbon monoxide, and methanol) into electricity and heat, but also reduce carbon dioxide and pollutant emissions and water usage. Solid oxide fuel cells, with their higher operating temperatures and favorable thermodynamic and reaction kinetic conditions not found in other fuel cells, offer broad application prospects for both large-scale, station-based, and small, portable solid oxide fuel cells. However, traditional solid oxide fuel cells face significant limitations in their application due to the high cost of their cells and poor durability over time.

[0003] In recent years, metal-supported solid oxide fuel cells (SOFCs) have attracted extensive research and attention due to their exceptional robustness, ability to withstand redox and thermodynamic cycles, and lower manufacturing costs compared to traditional anode- and electrolyte-supported SOFCs. The metal substrate of a SOFC not only supports the cell but also provides the gas flow channels on the anode side. However, due to the high density and hardness of the metal support and its resistance to deformation, the contact between the SOFC anode and the metal substrate is poor, and the metal support is unable to absorb the thermal expansion of the cell during the reaction.

[0004] In addition, existing solid oxide fuel cell stacks are generally large and bulky, requiring a series of auxiliary equipment to support their normal operation. These auxiliary equipment, such as air pumps, not only greatly increase the volume of the solid oxide fuel cell stack, but also increase the installation and maintenance costs of the solid oxide fuel cell stack. Summary of the Invention

[0005] In response to the above problems, the present invention provides a foam metal supported self-breathing solid oxide fuel cell stack, which can reduce the volume and cost of the solid oxide fuel cell stack, improve the start-stop performance, fuel adaptability and service life of the solid oxide fuel cell stack, and also improve the overall volume power density of the solid oxide fuel cell stack.

[0006] The present invention provides a self-breathing solid oxide fuel cell stack supported by foam metal, comprising: a first end plate, a second end plate and a plurality of stacked battery cells arranged between the first end plate and the second end plate, wherein the battery cells include: a bipolar plate, which is composed of a cathode plate and an anode plate bridged together, and a clamping structure is formed between two adjacent bipolar plates; the battery cells are built into the clamping structure; the foam metal, the anode plate and the active anode layer of the battery cell are respectively adhered to both sides of the foam metal, and the cathode plate is formed into a concave platform structure with multiple ventilation holes.

[0007] According to this technical solution, firstly, the use of foam metal as the support structure of solid oxide fuel cells can significantly reduce the manufacturing cost of battery cells. The foam metal material has excellent thermal conductivity, electrical conductivity and thermal stress absorption capacity. It is not only an ideal support and current collection conductive material for solid oxide fuel cells, but also can improve the durability of solid oxide fuel cells. The porous structure of the foam metal can also promote the rapid transmission of fuel gas and expand the surface area of the three-phase reaction interface, promote the electrochemical reaction of the anode, and improve the power density of the battery cell.

[0008] The cathode plate is formed into a concave structure with ventilation holes, so that air can enter the clamping structure through the ventilation holes and directly contact the cathode of the battery cell. There is no need to set up a cathode gas flow channel separately. This can reduce the flow channel arrangement in the solid oxide fuel cell stack and the processing of fine flow channels on the surface of the bipolar plate, reduce the complexity of the solid oxide fuel cell structure, reduce the processing difficulty and cost of the solid oxide fuel cell, reduce the use of solid oxide fuel cell auxiliary equipment, and reduce the volume and installation cost of the solid oxide fuel cell stack.

[0009] In addition, a battery stack formed by stacking multiple battery cells and clamping them with end plates is more convenient for disassembly and assembly when adding or reducing battery cells according to changes in output power.

[0010] As a preferred technical solution of the present invention, the battery cell is arranged in the recess of the cathode plate, and a plurality of vent holes are opened in the recess.

[0011] According to this technical solution, the battery cell is built into the recess of the cathode plate, and ventilation holes are provided in the recess, which can expand the contact area between the battery cell and the air and increase the efficiency of the battery cell in self-breathing with the external air through the ventilation holes.

[0012] As a preferred technical solution of the present invention, the battery unit further includes a metal mesh, and the cathode plate and the battery sheet are respectively attached to both sides of the metal mesh.

[0013] According to the technical solution, the metal mesh can be a silver mesh or a platinum mesh. The silver mesh fits tightly to the cathode surface of the battery cell, playing the role of collecting current; the silver mesh fits tightly to the cathode plate surface, so that the entire solid oxide fuel cell stack can form a series path.

[0014] As a preferred technical solution of the present invention, the foam metal is a porous Ni-Fe alloy.

[0015] According to this technical solution, Ni-Fe alloy materials have excellent electrical conductivity and strong oxidation resistance. Compared with stainless steel, Ni-Fe alloy does not contain Cr, which has less toxicity to the active anode of the battery cell. At the same time, its porous nature can increase the anode's fuel gas transmission rate, increase the contact area between the anode and the fuel gas, further promote the electrochemical reaction of the anode, and improve the power density of the battery cell.

[0016] As a preferred technical solution of the present invention, the thickness of the foam metal is 200-400 μm.

[0017] According to this technical solution, if the thickness of the foam metal is too low, it will easily lead to insufficient supporting force, and if the thickness is too high, it will hinder the penetration rate of the fuel gas. When the thickness of the foam metal is within 200-400μm, it can provide sufficient support for the solid oxide fuel cell stack while ensuring the fuel gas transmission rate of the anode.

[0018] As a preferred technical solution of the present invention, the cell sheet is a circular solid oxide fuel cell with a layered structure, and the solid oxide fuel cell stack is a cylindrical cell stack with multiple circular solid oxide fuel cells built in.

[0019] According to this technical solution, the circular solid oxide fuel cell with a layered structure has a simple structure and is easy to seal, and the solid oxide fuel cell stack is set as a cylindrical cell stack, that is, the first end plate, the second end plate and the bipolar plate are all formed into a circular structure, so that the solid oxide fuel cell is easier to assemble and seal, and the structure is more stable. In particular, the cylindrical geometric structure can effectively improve the efficiency of air circulation between the cathode plate and the anode plate, thereby achieving better self-breathing function.

[0020] As a preferred technical solution of the present invention, through holes are opened at corresponding positions on the first end plate and the battery cell to form a fuel gas inlet channel; through holes are opened at corresponding positions on the second end plate and the battery cell to form a fuel gas outlet channel.

[0021] According to this technical solution, for the structure of a cylindrical layered solid oxide fuel cell stack, it is only necessary to penetrate the two bottom surfaces of the cylinder to supply fuel gas to all the battery cells inside the stack. The processing is simple and does not require a complicated fuel gas path setting, thereby simplifying the structure of the solid oxide fuel cell stack.

[0022] As a preferred technical solution of the present invention, a fuel gas flow channel is formed on the surface of the anode plate. The fuel gas flow channel is formed on the surface of the anode plate as a main flow channel connecting the fuel gas inlet channel and the fuel gas outlet channel and a plurality of serpentine annular auxiliary flow channels connected to the main flow channel.

[0023] According to this technical solution, the fuel gas enters the solid oxide fuel cell through the fuel gas inlet channel, and then flows into the anode plate from the main channel, filling the multiple serpentine annular auxiliary flow channels on the anode plate, increasing the contact area between the battery anode and the fuel gas, and improving the transmission efficiency of the fuel gas. The excess solid oxide fuel gas continues to flow from the main channel into the fuel gas outlet channel, which is convenient, fast, and easy to process.

[0024] As a preferred technical solution of the present invention, the bipolar plate also includes a sealing gasket, which is arranged around the battery cell between the cathode plate and the anode plate. Corresponding through mounting holes are also formed on the first end plate, the second end plate, multiple bipolar plates and the sealing gasket.

[0025] According to this technical solution, a combination of end plate clamping and bolt tightening is adopted for assembly, resulting in a stable structure. Only two long bolts are required to assemble and fix the solid oxide fuel cell stack, which is convenient for assembly and disassembly and more conducive to the circulation of air and fuel gas inside the stack. In addition, the compression fit of the sealing gasket and the bolt can achieve good airtightness.

[0026] As a preferred technical solution of the present invention, the hierarchical structure of the battery cell includes an active anode layer, an electrolyte layer, a barrier layer and an active cathode layer in sequence, and the electrolyte layer is sealed and connected to the bipolar plate and the sealing gasket with ceramic sealant.

[0027] According to this technical solution, air enters from the vents of the concave platform of the cathode plate, passes through the metal mesh and reaches the active cathode layer. Oxygen undergoes a reduction reaction near the three-phase reaction interface of the active cathode layer, and oxygen gains electrons to generate oxygen ions. The generated oxygen ions are transported to the active anode layer and react with the fuel gas to generate water vapor and carbon dioxide, thereby converting chemical energy into electrical energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a structural schematic diagram of a foam metal supported self-breathing solid oxide fuel cell stack provided in an embodiment of the present invention.

[0029] Figure 2 Schematic diagram of the structure of a battery unit in an embodiment of the present invention.

[0030] Figure 3 Schematic diagram of the structure of a bipolar plate of a battery cell in an embodiment of the present invention.

[0031] Reference numerals:

[0032] 11-first end plate; 12-second end plate; 13-mounting hole; 14-fuel gas inlet channel; 15-fuel gas outlet channel; 2-battery cell; 21-bipolar plate; 211-anode plate; 212-cathode plate; 213-fuel gas flow channel; 2131-main flow channel; 2132-auxiliary flow channel; 214-recess; 22-sealing gasket; 23-metal mesh; 24-battery cell; 241-active cathode layer; 242-barrier layer; 243-electrolyte layer; 244-active anode layer; 25-foam metal. DETAILED DESCRIPTION

[0033] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0034] It should be noted that the directions or positional relationships indicated by “left”, “right”, “inside” and “outside” in this embodiment are based on the directions or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they cannot be understood as a limitation on the present invention.

[0035] Figure 1 This is a schematic structural diagram of a foam metal-supported self-breathing solid oxide fuel cell stack provided in this embodiment.

[0036] like Figure 1 As shown, the foam metal supported self-breathing solid oxide fuel cell stack comprises: a first end plate 11, a second end plate 12 and a plurality of stacked battery cells 2 arranged between the first end plate 11 and the second end plate 12. In a preferred embodiment, as shown in FIG. Figure 1 As shown, the solid oxide fuel cell stack is a cylindrical battery stack, and the first end plate 11, the second end plate 12 and the battery unit 2 are all circular plate structures. Further preferably, the first end plate 11, the second end plate 12 and the plurality of battery units 2 have corresponding penetrating mounting holes 13. Figure 1The figure preferably shows a situation in which two mounting holes 13 are arranged at the upper and lower ends of the solid oxide fuel cell stack. Two long screws pass through the mounting holes 13 of the first end plate 11, multiple battery cells 2 and the second end plate 12 in turn, and are fastened with bolts. For a cylindrical solid oxide fuel cell stack, it is only necessary to fasten the two bottom surfaces of the cylinder (i.e., the first end plate 11 and the second end plate 12) with bolts, that is, the multiple battery cells 2 in the end plate can be fixed in a clamping manner. The bolt fastening structure is easy to assemble and disassemble and has good airtightness. In particular, the cylindrical geometric structure can effectively improve the efficiency of air circulation in the solid oxide fuel cell, thereby achieving better self-breathing function.

[0037] In addition, in this embodiment, the number of battery units 2 is preferably 2-12, and the power output of the solid oxide fuel cell stack can be flexibly adjusted as the number of stacked battery units 2 changes.

[0038] Figure 2 Schematic diagram of the structure of a battery unit in this embodiment. Figure 3 Schematic diagram of the structure of a bipolar plate of a battery cell in this embodiment. Figure 2 and Figure 3 From a perspective, a single battery cell 13 includes: a bipolar plate 21 , including a cathode plate 212 and an anode plate 211 , as well as a metal mesh 23 , a battery sheet 24 and a foam metal 25 built into the bipolar plate 21 .

[0039] The bipolar plate 21 is composed of an anode plate 211 and a cathode plate 212 connected by a bridge, and a clamping structure is formed between two adjacent bipolar plates. Figure 3 As shown, the anode plate 211 and the cathode plate 212 are connected by bolts only at the upper and lower mounting holes 13 .

[0040] The cathode plate 212 is a recessed platform with multiple ventilation holes (not shown). Preferably, multiple ventilation holes are opened in the recess 214, and the recess 214 can accommodate components such as the battery cell 24, so that air can enter the bipolar plate 21 through the ventilation holes in the recess 214 and react with the cathode of the battery cell 24, without the need to set up an additional air flow channel and air pump device.

[0041] like Figure 3 As shown, through holes are further provided at corresponding positions on the first end plate 11 and the battery cell 2 to form a fuel gas inlet channel 14; through holes are further provided at corresponding positions on the second end plate 12 and the battery cell 2 to form a fuel gas outlet channel 15. A fuel gas flow channel 213 is formed on the surface of the anode plate 211. The fuel gas flow channel 213 is formed on the surface of the anode plate 211 as a main flow channel 2131 connecting the fuel gas inlet channel 14 and the fuel gas outlet channel 15, and a plurality of serpentine annular auxiliary flow channels 2132 connected to the main flow channel 2131.

[0042] Specifically, for the structure of a cylindrical layered solid oxide fuel cell stack, it is only necessary to penetrate the two bottom surfaces of the cylinder (i.e., the first end plate 11 and the second end plate 12) to supply fuel gas to all the battery cells 2 inside the battery stack. The fuel gas enters the solid oxide fuel cell stack through the fuel gas inlet channel 14, and then flows into the battery cell 2 through the main channel 2131 on the anode plate 211. At the end of the main channel 2131, it is divided into two streams and flows into two serpentine annular auxiliary channels 2132. The unreacted fuel gas and reaction products converge into the fuel gas outlet channel 15 at the end of the auxiliary channel, thereby increasing the contact area between the battery anode and the fuel gas and improving the transmission efficiency of the fuel gas.

[0043] Preferably, the bipolar plate 21 further includes a sealing gasket 22, which is disposed around the battery cells 24 and between the cathode plate 212 and the anode plate 211. Corresponding mounting holes 13 are also formed on the first end plate 11, the second end plate 12, the plurality of bipolar plates 21, and the sealing gasket 22. The assembly method of combining end plate clamping and bolt fastening provides a stable structure, and only two long bolts are required to assemble and secure the solid oxide fuel cell stack, making assembly and disassembly easier and more conducive to the circulation of air and fuel gas within the stack. Furthermore, the compression fit between the sealing gasket 22 and the bolts ensures excellent airtightness.

[0044] The metal mesh 23 is fitted with the cathode plate 212 and the battery cell 24, that is, the cathode plate 212 and the battery cell 24 are respectively fitted on both sides of the metal mesh 23. Spacing the battery cell 24 and the cathode plate 212 can provide more space for air flow. It is worth mentioning that the metal mesh 23 collects the current generated by the active cathode layer 241, thereby reducing the resistance between the active cathode layer 241 and the cathode plate 212.

[0045] The battery cell 24 is built into the clamping structure of the bipolar plate 21, wherein the cathode of the battery cell 24 is arranged corresponding to the cathode plate 212 of the previous bipolar plate 21, and the anode of the battery cell 24 is arranged corresponding to the anode plate 211 of the next bipolar plate 21. Preferably, the battery cell 24 is arranged in the recess 214 of the cathode plate 212. Figure 2 The example in FIG. 2 shows a case where the cell sheet 24 is a circular solid oxide fuel cell with a layered structure. The structure of the layered solid oxide fuel cell is as follows:

[0046] NiO-YSZ|YSZ|GDC|LSCF-GDC;

[0047] NiO-YSZ is the active anode layer 244, YSZ is the electrolyte layer 243, GDC is the barrier layer 242, and LSCF-GDC is the active cathode layer 241. The circular solid oxide fuel cell with a layered structure is simple and easy to seal. The cell sheet of the present invention is not limited to this, and the use of other solid oxide fuel cells also falls within the scope of protection of the present invention.

[0048] The metal foam 25 is laminated to the anode plate 211 and the cell 24. Specifically, the anode plate 211 and the active anode layer 244 of the cell 24 are laminated to either side of the metal foam 25. The metal foam 25 is preferably made of a porous Ni-Fe alloy. This porous Ni-Fe alloy has excellent electrical conductivity and strong oxidation resistance. Compared to stainless steel, it contains no Cr and has less toxicity to the active anode of the cell 24. This porous nature also increases the anode fuel gas transmission rate, increases the contact area between the anode and the fuel gas, further promotes the electrochemical reaction at the anode, and improves the power density of the cell 24. Furthermore, the thickness of the metal foam 25 is preferably 200-400 μm. If the thickness of the foam metal 25 is too low, it may easily lead to insufficient supporting force, while if the thickness is too high, it will hinder the penetration rate of the fuel gas. When the thickness of the foam metal 25 is within 200-400μm, it can provide sufficient support for the solid oxide fuel cell stack while ensuring the fuel gas transmission rate of the anode. Further preferably, when the thickness of the foam metal 25 is 300μm, it can take into account both the fuel gas transmission rate and the supporting force, thereby maximizing the performance of the solid oxide fuel cell.

[0049] Specifically, fuel gas (such as hydrogen, carbon monoxide, methanol and methane, etc.) flows in from the fuel gas inlet channel 14 of the first end plate 11, circulates in the entire fuel gas inlet channel 14, and then flows into the fuel gas flow channel 213 of the anode plate 211. When flowing in the fuel gas flow channel 213, the fuel gas penetrates into the foam metal 25 and is transferred to the active anode layer 244 through the larger pores of the foam metal 25. After reaching the active anode layer 244, the fuel gas is oxidized near its three-phase reaction interface, and combines with the oxygen ions near the three-phase reaction interface to generate water vapor and carbon dioxide. The water vapor and carbon dioxide leave the active anode layer 244 by diffusion and pass through the foam metal 25 into the fuel gas flow channel 213. They leave the fuel gas flow channel 213 of the anode plate 211 along with part of the fuel gas that does not participate in the reaction, and then enter the fuel gas outlet channel 15 together to leave the self-breathing solid oxide fuel cell stack supported by the foam metal 25.

[0050] In this embodiment, the use of metal foam 25 provides sufficient mechanical strength for the functional layers of the solid oxide fuel cell, allowing the cell 24 to be made thinner. This not only reduces the resistance of ion transport and improves the power density of the solid oxide fuel cell, but also reduces the use of expensive ceramic materials, significantly reducing the production cost of the battery cell 13. It also improves the transmission efficiency of fuel gas, water vapor, and carbon dioxide. The smaller pores of the metal foam 25 increase the contact area with the active anode layer 244, expanding the area of the three-phase reaction interface and promoting the electrochemical reaction near the three-phase reaction interface on the anode side. Electrons generated by the oxidation reaction are collected by the metal foam 25 and then conducted to the bipolar plate 21. Compared to a current collection and conductive structure in which the active anode layer 244 directly contacts the bipolar plate 21, the use of metal foam 25 improves the current collection efficiency of the solid oxide fuel cell, reduces the direct contact resistance between the active anode layer 244 and the bipolar plate 21, and increases the power density of the cell 24.

[0051] Air enters through the porous structure of the recess 214 of the cathode plate 212, passes through the metal mesh 23 and reaches the active cathode layer 241. Oxygen undergoes a reduction reaction near the three-phase reaction interface of the active cathode layer 241, and oxygen gains electrons to generate oxygen ions. The generated oxygen ions are transported to the active anode layer 244 and react with the fuel gas to generate water vapor and carbon dioxide. The oxygen ions need to pass through the active cathode layer 241, the barrier layer 242, the electrolyte layer 243 and the active anode layer 244 in sequence.

[0052] Compared with the oxygen supply method of the cathode of the traditional solid oxide fuel cell using flow channel transport, the cathode of the cylindrical self-breathing solid oxide fuel cell stack supported by foam metal uses a self-breathing oxygen supply method, which can reduce the flow channel arrangement in the solid oxide fuel cell stack and the processing of fine flow channels on the surface of the bipolar plate 21, reduce the complexity of the solid oxide fuel cell structure, and reduce the processing difficulty and cost of the solid oxide fuel cell; reduce the difficulty of airtightness of the solid oxide fuel cell stack, so that the airtightness of the solid oxide fuel cell stack is improved; it can also reduce the use of gas supply auxiliary equipment, reduce the cost of the solid oxide fuel cell stack, and improve the power density per unit volume.

[0053] The cylindrical, self-breathing solid oxide fuel cell stack supported by metal foam utilizes a cylindrical geometry that effectively improves the efficiency of air circulation between the cathode plate 212 and the anode plate 211, thereby achieving enhanced self-breathing functionality. This geometry also enhances the compactness of the membrane electrode assembly, improving the airtightness of the solid oxide fuel cell stack and reducing fuel gas leakage. The cylindrical, self-breathing solid oxide fuel cell stack, secured by a circular end plate and a long screw and nut structure, can adjust the number of repeating battery cells 2 based on the required power. While ensuring compactness and airtightness, it facilitates disassembly and assembly, initially meeting the requirements of today's solid oxide fuel cell architectures for small, portable applications.

[0054] In this embodiment, a method for preparing the solid oxide fuel cell stack is also provided, comprising the following steps:

[0055] (1) Component preparation

[0056] The materials of the first end plate 11, the second end plate 12, the long screw and the bolt are Crofer22 metal, SUS430 metal or SUS441 metal; the material of the bipolar plate 21 is Crofer22 metal, SUS430 metal or SUS441 metal; the metal mesh 23 is a silver mesh or a platinum mesh; the thickness of the metal mesh 23 is 0.05 to 0.15 mm, and the mesh size is (0.2 to 0.4) mm by (0.5 to 0.7) mm; the foam metal 25 is a porous NiCrAl alloy, and the thickness of the foam metal is 300 μm.

[0057] The bonding methods of the battery cell 24 and the metal foam 25 include but are not limited to the following methods:

[0058] The anode slurry is deposited on one side of the foam metal 25 by using a tape casting technique, dried at room temperature and then kept at 1100° C. for 2 hours to form an active anode layer 244 on one side of the foam metal 25;

[0059] On the other side of the active anode layer 244, Y2O3 doped ZrO2 is prepared by screen printing or coating as the electrolyte layer 243, and sintered at a temperature of 1250-1500°C to ensure that the active anode layer 244 and the electrolyte layer 243 are tightly bonded;

[0060] On the other side of the electrolyte layer 243, a Gd2O3-doped CeO2 thin layer is prepared on the electrolyte layer 243 by magnetron sputtering or plasma spraying as a barrier layer 242, and the temperature is kept at 1380°C for 2 hours;

[0061] Then, an active cathode layer 241 is prepared on the barrier layer 242 by screen printing or coating.

[0062] (2) Stack assembly

[0063] The metal mesh 23, battery cell 24 and foam metal 25 are placed in the recess 214 of the cathode plate 214, and the battery cell 24, the recess 214 and the sealing gasket 22 are bonded and sealed with glass ceramic sealant; the metal mesh 23, battery cell 24 and foam metal 25 are clamped and fastened between two adjacent bipolar plates by a clamping structure consisting of bipolar plate-sealing gasket-bipolar plate, the metal mesh 23 is in close contact with the porous recess 214 of the cathode plate 212, and the foam metal 25 is in close contact with the fuel gas flow channel 213 of the anode plate 211.

[0064] A first end plate 11 and a second end plate 12 clamp several battery cells 2. Two long screws are inserted through the first end plate 11, the battery cells 2, and the upper and lower mounting holes 13 of the second end plate 12, respectively, and then fastened with bolts. This bolt-fastening structure is easy to assemble and disassemble, and has good airtightness. The power output of the metal foam-supported solid oxide fuel cell stack can be flexibly adjusted according to changes in the number of battery cells 2.

[0065] In this embodiment, first, the use of foam metal 25 as the support layer of the solid oxide fuel cell can significantly reduce the manufacturing cost of the battery unit 2. The foam metal material has excellent thermal conductivity, electrical conductivity and thermal stress absorption capacity. It is not only an ideal support and current collecting conductive material for the solid oxide fuel cell, but also can improve the durability of the solid oxide fuel cell. The porous structure of the foam metal can also promote the rapid transmission of fuel gas and expand the surface area of the three-phase reaction interface, promote the electrochemical reaction of the anode, and improve the power density of the battery cell.

[0066] Then, a recess 214 structure having a plurality of air vents is provided on the cathode plate 212, so that air can enter the recess 214 through the air vents and directly contact the cathode of the battery cell 24, without the need to separately provide a cathode gas flow channel. This can reduce the flow channel arrangement in the solid oxide fuel cell stack and the processing of fine flow channels on the surface of the bipolar plate 21, reduce the complexity of the solid oxide fuel cell structure, reduce the processing difficulty and cost of the solid oxide fuel cell, reduce the use of solid oxide fuel cell auxiliary equipment, and reduce the volume and installation cost of the solid oxide fuel cell stack.

[0067] In addition, the battery stack formed by stacking multiple battery cells 2 and clamping them with end plates is more convenient for disassembly and assembly when adding or reducing battery cells according to changes in output power. The cylindrical geometric structure can also effectively improve the efficiency of air circulation between the cathode plate 212 and the anode plate 211, thereby achieving a higher self-breathing function.

[0068] The technical solutions of the present invention have been described above in conjunction with the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is not limited to the above specific embodiments. Without departing from the principles of the present invention, those skilled in the art may make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will fall within the scope of protection of the present invention.

Claims

1. A foam metal supported self-breathing solid oxide fuel cell stack comprising: A first end plate, a second end plate, and a plurality of stacked battery cells disposed between the first end plate and the second end plate, wherein the battery cells include: Bipolar plates, each of which is composed of a cathode plate and an anode plate bridged together, with a clamping structure formed between two adjacent bipolar plates; A battery cell, built into the clamping structure; Foam metal, the anode plate and the active anode layer of the battery cell are respectively attached to both sides of the foam metal, The cathode plate is formed into a concave structure with a plurality of ventilation holes. The battery cell is disposed in a recessed portion of the cathode plate, and the plurality of vent holes are provided in the recessed portion; The foam metal is a porous Ni-Fe alloy, and the thickness of the foam metal is 200-400 μm.

2. A foam metal supported self-breathing solid oxide fuel cell stack according to claim 1, characterized in that: The battery unit further comprises: The cathode plate and the battery cell are respectively attached to two sides of the metal mesh.

3. The foam metal supported self-breathing solid oxide fuel cell stack according to claim 1, characterized in that: The cell sheet is a circular solid oxide fuel cell with a layered structure, and the solid oxide fuel cell stack is a cylindrical cell stack in which a plurality of the circular solid oxide fuel cells are built.

4. The foam metal supported self-breathing solid oxide fuel cell stack according to claim 3, characterized in that: Through holes are provided at corresponding positions on the first end plate and the battery unit to form a fuel gas inlet channel; Through holes are provided at corresponding positions on the second end plate and the battery unit to form a fuel gas outlet channel.

5. The foam metal supported self-breathing solid oxide fuel cell stack according to claim 4, characterized in that: A fuel gas flow channel is formed on the surface of the anode plate. The fuel gas flow channel is formed on the surface of the anode plate as a main flow channel connecting the fuel gas inlet channel and the fuel gas outlet channel and a plurality of serpentine annular auxiliary flow channels connected to the main flow channel.

6. The foam metal supported self-breathing solid oxide fuel cell stack according to any one of claims 3 to 5, characterized in that: The bipolar plate further includes a sealing gasket, which surrounds the battery cell and is disposed between the cathode plate and the anode plate. Corresponding through mounting holes are also formed on the first end plate, the second end plate, the plurality of bipolar plates and the sealing gasket.

7. The foam metal supported self-breathing solid oxide fuel cell stack according to claim 6, characterized in that: The hierarchical structure of the battery cell sequentially comprises an active anode layer, an electrolyte layer, a barrier layer and an active cathode layer. The electrolyte layer is sealed with the bipolar plate and the sealing gasket using ceramic sealant.

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