Integrally packaged solid oxide electric pile

Abstract

The invention relates to an integrally packaged solid oxide stack. A disc spring is arranged between a top plate and a pressurizing plate; the sealing nut is embedded in the bottom plate; an insulating bolt sequentially penetrates through the pressurizing plate, the disc spring, the top plate, the compression piece of each repeating unit, the connecting plate and the bottom plate, and is matched and fastened with a sealing nut to form an independent sealed electric pile unit; tension provided by the insulating bolt acts on the disc spring and the compression piece, the disc spring generates fastening force in the vertical direction, and the compression piece generates fastening force in the horizontal direction. According to the electric pile, compact design is achieved through the built-in fastening assembly, and the situation that an external fastening piece occupies space is avoided; the structural stability in all directions is greatly improved through bidirectional fastening, and the horizontal anti-shearing capacity is enhanced; the elastic component can be dynamically matched with size change caused by temperature change, and fastening failure is avoided; the stack does not need an additional fastening mechanism due to integrated packaging, and the built-in fastening assembly realizes an anti-disassembly effect, so that the independence is improved, and the large-scale application and industrialization process of the solid oxide stack are effectively promoted.

Description

Technical Field

[0001] This invention relates to the field of solid oxide fuel cell technology, and more specifically to an integrated packaged solid oxide fuel cell. Background Technology

[0002] High-temperature solid oxide (SOFC) technology is a class of electrochemical technologies that utilize solid electrolytes to achieve the interconversion of chemical energy with electrical and thermal energy. Among these technologies, solid oxide fuel cells (SOFCs) are the core application devices. Because they use solid oxides as the electrolyte, SOFCs possess an all-solid-state structure, offering not only no corrosion or leakage risks and extremely high safety, but also the flexibility to be designed for individual use or combined use of multiple individual stacks, depending on actual current and voltage requirements or fuel supply conditions, demonstrating significant commercial application potential.

[0003] Structurally, solid oxide fuel cell stacks mainly consist of upper and lower end plates and repeating units. Each repeating unit is formed by vertically stacking connectors, batteries, seals, and current collectors. Multiple repeating units are further stacked with the upper and lower end plates to assemble a complete fuel cell stack. In practical applications, fuel cell stacks have specific requirements for fastening: Firstly, during transportation and storage, the components must be tightly fitted without relative looseness to prevent slippage of stacked components due to vibration, tilting, or other external factors, which could lead to stack deformation and failure. Secondly, during operation, a stable fastening force must be applied vertically. This serves two purposes: first, to ensure sufficient fastening pressure between the seals and adjacent components, allowing the seals to effectively seal and prevent gas leakage that could cause combustion, thus extending the stack's lifespan; second, to ensure close contact between the batteries, connectors, current collectors, and other charged components, minimizing contact resistance and improving the stack's electrical performance.

[0004] To meet the above-mentioned fastening requirements, while taking into account the compactness of the fuel cell stack and the control of material costs, the components of the fuel cell stack are usually designed as thin plate structures with a thickness of 0.5mm to 3mm. It is difficult to achieve self-fastening between components through structural design. At present, the industry mainly uses the following two fastening methods, but both have obvious defects.

[0005] The first type of fastening method is bolt fastening, which involves designing fastening points (such as fastening holes) on some components of the fuel cell stack (such as upper and lower end plates) and using bolt assemblies to connect and fasten the components. For example, the solid oxide fuel cell stack disclosed in CN102122722B connects the upper current collector, stacking mechanism and lower current collector with bolt assemblies. By improving the fixing and pressurizing method of the upper and lower current collectors and stacking structure, there are no bolts protruding on the outside of the current collector, which facilitates series or parallel connection between stacks. However, this method still has a key problem: the bolts occupy the space around the fuel cell stack, which can easily cause interference when the fuel cell stack is used with external equipment or when multiple fuel cell stacks are densely arranged, seriously affecting the compactness of the fuel cell stack. At the same time, this method clearly requires that after the fuel cell stack is assembled, an additional pressure of 0~400 kg must be applied after heating, which means that the assembled fuel cell stack does not have complete functions and must rely on external additional fastening force to be used normally. For example, CN216427428U directly connects the upper and lower fixing plates with bolts, which also fails to solve the problem of bolts occupying external space and affecting the compactness of the fuel cell stack. Another example is the solid oxide fuel cell stack disclosed in CN107248586B, which has fixing holes at the four corners of the end plates and through holes in the upper plate, lower plate, and stacked structure. Tubular insulating components are inserted into these holes, and the stack is connected using bolts with insulating films on their surfaces or bolts surrounded by insulating components to improve electrical stability. However, this method has core flaws: first, it ignores the impact of processing and assembly errors on the fastening effect; second, the insulating components and through holes cannot maintain an ideal limiting relationship under all operating conditions from room temperature to high temperature, failing to form a stable whole. This causes the assembled fuel cell stack to easily deform under lateral shear forces, severely compromising its stability.

[0006] The second type of fastening method is the external independent fastening device, which achieves pressure fastening by installing an independent fastening device around the fuel cell stack. For example, the fastening device disclosed in CN109244516B uses an X-shaped pressure frame in conjunction with main and auxiliary pressure blocks to achieve multi-point pressure, and adds a sidewall pressure structure to achieve comprehensive pressure. However, this device has two key shortcomings: first, the core pressure mechanism only uses a combination of adjusting bolts and pressure plates, without considering the bolt unloading problem caused by plastic deformation after long-term stress on the fuel cell stack; second, when the fuel cell stack heats up to its operating temperature, it will undergo dimensional changes due to thermal expansion, and the bolts, which are fixed after installation, do not have dynamic adjustment capabilities, which may ultimately lead to two failure outcomes: either the tight contact between the bolts and the fuel cell stack disappears, resulting in complete unloading, or the pressure increases sharply, damaging components and causing the pressure device to fail completely. For example, CN206639869U uses springs and bolts outside the hot box to apply pressure to the fuel cell stack between the top cover and the base to prevent pressure failure caused by mismatch in the coefficients of thermal expansion of the fuel cell stack components. However, this method also has obvious drawbacks: First, the size of the fastening device is much larger than the size of the fuel cell stack body, and it requires an external platform of sufficient height to be used, which is not practical. Second, only the top cover and the base are equipped with fiber slots that cooperate with the pressure bar, and the fuel cell stack itself has no measures to resist shear force, resulting in poor lateral stability. Third, the device components are scattered, making it impossible to form a fully functional single unit of fuel cell stack, and it is difficult to realize the combined use of multiple stacks.

[0007] In summary, existing solid oxide fuel cell stack fastening and encapsulation technologies generally suffer from three major problems. First, insufficient structural compactness: to accommodate bolt installation space or external fastening devices, dedicated pressure zones are required around the stack components, hindering the integrated installation of multiple stacks. Second, poor reliability of horizontal fastening: current technologies achieve stacking fastening solely through vertical pressure, with horizontal shear resistance entirely dependent on friction generated by vertical pressure. This indirect fastening method suffers from poor stability and cannot withstand lateral forces during transportation or use. Third, lack of stack integrity and enclosure: as the smallest usable unit, the fuel cell stack should possess complete functionality. However, current technologies require continuous monitoring of the fastening mechanism and lack innovative encapsulation processes, easily dispersing into multiple fragmented components, failing to form independent, enclosed single units. This low independence severely restricts the large-scale production and industrialization of solid oxide fuel cell stacks. Summary of the Invention

[0008] To address the problems of non-compact stack structure, insufficient horizontal fastening reliability, and lack of integrated sealing in the existing technology, this invention aims to provide an integrated packaged solid oxide fuel cell stack.

[0009] According to the present invention, an integrated packaged solid oxide fuel cell stack includes a base plate, multiple sets of repeating units, a top plate, and a pressure plate stacked sequentially from bottom to top. Each set of repeating units includes a connecting plate and a compression member disposed on the upper side of the connecting plate; a disc spring disposed between the top plate and the pressure plate; a sealing nut embedded in the base plate; and an insulating bolt that sequentially passes through the pressure plate, the disc spring, the top plate, the compression member and connecting plate of each repeating unit, and the base plate, and is fastened with the sealing nut to form an independent and closed fuel cell stack unit. The tensile force provided by the insulating bolt acts on the disc spring and the compression member, the disc spring generating a vertical fastening force, and the compression member generating a horizontal fastening force.

[0010] In a preferred embodiment, the disc spring and the compression member dynamically adapt to the dimensional changes caused by temperature variations in the integrated packaged solid oxide fuel cell through elastic deformation.

[0011] In a preferred embodiment, the connecting plate is provided with a first stepped through hole structure, the first stepped through hole structure including an upper first section and a lower second section arranged concentrically, the diameter of the first section being larger than the diameter of the second section, the first section forming a connecting plate positioning groove, and the second section forming a connecting plate positioning hole; at least a portion of the compression member is disposed in the connecting plate positioning groove, and the insulating bolt passes through the connecting plate positioning hole.

[0012] In a preferred embodiment, the compression component is generally annular, comprising an outer contour, an arc-shaped thin plate, and an inner contour. The arc-shaped thin plate is a thin, arc-shaped transition structure located in the middle and connecting the outer and inner contours. Both the outer and inner contours of the compression component are circumferentially arranged serrations, with the serrations being relatively independent. When not under stress, the outer tangent circle diameter of the serrations on the outer contour of the compression component is smaller than the inner diameter of the positioning groove on the connecting plate, and the outer tangent circle diameter of the serrations on the inner contour of the compression component is larger than the diameter of the central cylinder of the insulating bolt. The thickness of the compression component is greater than the depth of the positioning groove on the connecting plate.

[0013] In a preferred embodiment, the pressure plate is provided with a stepped blind hole structure, which includes a lower third section and an upper fourth section arranged concentrically. The diameter of the third section is larger than the diameter of the fourth section. The third section forms a pressure plate positioning groove, and the fourth section forms a pressure plate threaded hole. At least a portion of the disc spring is disposed in the pressure plate positioning groove, and the pressure plate threaded hole is threaded with the upper side of the insulating bolt.

[0014] In a preferred embodiment, the stepped blind hole structures are evenly distributed at the four corners of the pressure plate within the horizontal range of the pressure plate, and the distance from the center of each stepped blind hole structure to the center of the pressure plate is equal.

[0015] In a preferred embodiment, the base plate is provided with a second stepped through hole structure, which includes a fifth section at the top and a sixth section at the bottom, both arranged concentrically. The diameter of the fifth section is smaller than the diameter of the sixth section. The fifth section forms a base plate positioning hole, and the sixth section forms a base plate nut hole. The diameter of the base plate positioning hole is larger than the diameter of the central cylinder of the insulating bolt, and the inner diameter of the base plate nut hole is larger than the outer diameter of the closed nut. The connection between the base plate nut hole and the base plate positioning hole forms an annular force-bearing surface, which is located on the inner side of the base plate.

[0016] In a preferred embodiment, the depth of the bottom plate nut hole is greater than the thickness of the sealing nut, and the sealing nut does not protrude from the lower side plane of the bottom plate; the sealing nut is fixed to the inner wall of the bottom plate nut hole by welding.

[0017] In a preferred embodiment, the middle part of the insulating bolt is a smooth cylindrical section, and the insulating bolt achieves its insulating function by high-temperature spraying of a ceramic insulating coating or by fitting an insulating sleeve that is attached to the cylindrical section.

[0018] In a preferred embodiment, the insulating bolt and the sealing nut are an integrated structure.

[0019] This invention achieves a compact design for the fuel cell stack through built-in fastening components, effectively avoiding the space-consuming and multi-stack integration issues caused by external fasteners. The bidirectional fastening action in both vertical and horizontal directions significantly improves the structural stability of the fuel cell stack in all directions, especially enhancing its horizontal shear resistance, overcoming the reliability deficiencies of traditional indirect fastening methods that rely solely on vertical pressure to generate friction. By utilizing the continuous elastic deformation of elastic components from room temperature to high temperature, dynamic matching between the fastening force and the temperature-induced dimensional changes of the fuel cell stack is achieved, preventing fastening failures caused by temperature variations. The integrated packaging design allows the fuel cell stack to form an independent, closed functional unit, eliminating the need for additional fastening mechanisms, thus improving component independence and effectively promoting the large-scale application and industrialization of solid oxide fuel cell stacks. Attached Figure Description

[0020] Figure 1 This is an exploded view of the integrally packaged solid oxide fuel cell according to the present invention.

[0021] Figure 2 yes Figure 1 A schematic diagram of the pressure plate structure.

[0022] Figure 3 yes Figure 1 A schematic diagram of the top plate structure.

[0023] Figure 4 yes Figure 1 A schematic diagram of the compression component.

[0024] Figure 5 yes Figure 1 A cross-sectional view of the compressed component.

[0025] Figure 6 yes Figure 1 A schematic diagram of the connecting plate.

[0026] Figure 7 yes Figure 1 A schematic diagram of the base plate.

[0027] Figure 8 yes Figure 1 A schematic diagram of the structure of a closed nut. Detailed Implementation

[0028] The preferred embodiments of the present invention are given below with reference to the accompanying drawings and described in detail.

[0029] like Figure 1 As shown, the integrated packaged solid oxide fuel cell stack according to the present invention includes a pressure plate 1, a disc spring 2, a top plate 3, an insulating bolt 4, a compression member 5, a connecting plate 6, a bottom plate 7, and a sealing nut 8. The bottom plate 7, multiple sets of repeating units, the top plate 3, and the pressure plate 1 are stacked from bottom to top. Each repeating unit consists of a compression member 5 and a connecting plate 6. The disc spring 2 is installed between the top plate 3 and the pressure plate 1. The sealing nut 8 is embedded in the bottom plate. The insulating bolt 4 passes through the pressure plate 1, disc spring 2, top plate 3, compression member 5, connecting plate 6, and bottom plate 7 and is fastened by the sealing nut 8, ultimately forming a complete and independent fuel cell stack unit. It should be understood that the repeating unit is the core functional unit of the fuel cell stack. To form a complete and usable fuel cell stack, in addition to the need to machine flow channels on both sides of the connecting plate 6 for gas flow, the repeating unit also contains commonly used components in the industry (not shown in the figure), such as seals, current collectors, and batteries. It should be understood that the number of repeating units is determined by the power requirements of the fuel cell stack (not less than one set, and the higher the power, the more units are required).

[0030] like Figure 2As shown, the pressure plate 1 has a stepped blind hole structure (not penetrating the pressure plate 1), including a concentrically arranged lower section with a large diameter and an upper section with a small diameter. The lower section forms a pressure plate positioning groove 21, the inner diameter of which is slightly larger than the upper outer diameter of the disc spring 2, used to position the disc spring 2, thereby achieving precise positioning of the disc spring 2 through the pressure plate positioning groove 21 and preventing the disc spring 2 from shifting. The upper section forms a pressure plate threaded hole 22, the internal thread of which matches the upper thread of the insulating bolt 4, thereby cooperating with the insulating bolt 4 through the pressure plate threaded hole 22. By rotating the insulating bolt 4, the compression of the disc spring 2 by the pressure plate 1 can be adjusted, and the tension of the insulating bolt 4 can be converted into pressure on the disc spring 2. It should be understood that the stepped blind hole structure is uniformly distributed within the horizontal range of the pressure plate 1. Preferably, the stepped blind hole structure is uniformly distributed at the four corners of the pressure plate 1, and the distance from the center of each stepped blind hole structure to the center of the pressure plate 1 is equal, that is, the distribution center of all stepped blind hole structures is on the same plumb line as the center of the pressure plate 1.

[0031] like Figure 3 As shown, the top plate 3 has a top plate positioning hole 31 with a through-hole structure. Its inner diameter is slightly larger than the diameter of the central cylinder of the insulating bolt 4 to facilitate the assembly of the insulating bolt 4. The number of top plate positioning holes 31 is the same as the number of pressure plate positioning slots 21, and their positions correspond. It should be understood that the top plate 3 serves as a connecting element, with the disc spring 2 placed on its upper side (the center of the disc spring 2 is aligned with the top plate positioning hole 31), and its lower side fitting against the upper side of the connecting plate 6 of the uppermost repeating unit, used to transmit the pressure of the pressure plate 1 and the disc spring 2 to the repeating unit below.

[0032] The aforementioned placement of the positioning groove corresponding to the disc spring 2 on the lower side of the pressure plate 1 with internal threads, instead of on the top plate 3 with a simple positioning hole, aims to reduce the number of complex parts in the device and improve the reliability of the invention. Eliminating the pressure plate positioning groove 21 on the lower side of the pressure plate 1 and instead creating a positioning groove on the upper side of the top plate 3, while simultaneously rotating the axis of the disc spring 2 by 180°, still achieves the positioning of the disc spring 2, reducing the processing complexity of the pressure plate, which is also entirely feasible.

[0033] like Figure 4 As shown, the connecting plate 6 has a stepped through-hole structure, including a concentric upper section with a large diameter and a lower section with a small diameter. The upper section forms a connecting plate positioning groove 61, the inner diameter of which is slightly larger than the lower outer diameter of the compression member 5, for positioning the compression member 5, thereby achieving pre-positioning of the compression member 5 through the connecting plate positioning groove 61 and preventing the compression member 5 from shifting. The lower section forms a connecting plate positioning hole 62 for the insulating bolt 4 to pass through. It should be understood that the connecting plate 6 is the skeleton of the repeating unit, used to support the compression member 5 and other conventional components. The upper side of the connecting plate 6 of each repeating unit is stacked with the compression member 5; the lower side of the connecting plate 6 of the previous repeating unit is directly pressed against the upper side of the compression member 5 of the next repeating unit; the lower side of the connecting plate 6 of the bottommost repeating unit is attached to the upper side of the base plate 7.

[0034] like Figure 5 and Figure 6 As shown, the compression component 5 is generally annular, comprising an outer contour 51, an arc-shaped thin plate 52, and an inner contour 53. The arc-shaped thin plate 52 is located in the middle of the compression component 5, connecting the outer contour 51 and the inner contour 53, and is a thin arc-shaped transition structure capable of elastic deformation. The outer contour 51 of the compression component has circumferentially arranged serrations, and the diameter of the outer tangent circle of the serrations when not under stress is smaller than the inner diameter of the positioning groove 61 of the connecting plate. The inner contour 53 of the compression component has circumferentially arranged serrations, and the diameter of the outer tangent circle of the serrations when not under stress is larger than the diameter of the central cylinder of the insulating bolt 4, allowing the insulating bolt 4 to pass through the compression component 5. The overall thickness of the compression component 5 is greater than the depth of the positioning groove 61 of the connecting plate (ensuring that the upper side of the compression component 5 can protrude from the groove and be squeezed by the upper connecting plate 6). In its initial state, the compression component 5 has gaps with the inner wall of the positioning groove 61 of the connecting plate and the insulating bolt 4. Its upper side is squeezed by the lower side of the upper connecting plate 6 of the top plate 3 / the upper set of repeating units. The arc-shaped thin plate 52 undergoes elastic deformation. After being deformed by force, the diameter of the outer tangent circle of the sawtooth of the outer contour 51 increases, and the diameter of the outer tangent circle of the sawtooth of the inner contour 53 decreases. Finally, the outer contour 51 of the compression component is tightly fitted with the inner wall of the positioning groove 61 of the connecting plate (horizontal radial fastening), and the inner contour 53 of the compression component is tightly fitted with the central cylinder of the insulating bolt 4 (horizontal axial fastening). This converts the pressure in the vertical direction into the fastening force in the horizontal direction, achieving double limiting in the horizontal direction. Thus, through the elastic deformation of the arc-shaped thin plate 52, it adapts to the size changes caused by the temperature change of the fuel cell stack (dynamic matching fastening force).

[0035] like Figure 7 As shown, the base plate 7 has a stepped through-hole structure, including a concentrically arranged upper section with a small diameter and a lower section with a large diameter. The upper section forms a base plate positioning hole 71, with the same diameter as the top plate positioning hole 31, for the insulating bolt 4 to pass through. The lower section forms a base plate nut hole 72, the inner diameter of which is slightly larger than the outer diameter of the sealing nut 8. Because the diameter of the base plate nut hole 72 is larger than that of the base plate positioning hole 71, a stepped surface is formed at the junction of the two, which forms an annular force-bearing surface 74. The force-bearing surface 74 of the base plate nut hole 72 bears the vertical tensile force transmitted by the insulating bolt 4, and the force-bearing surface 74 is located on the inner side of the base plate 7. Compared with a design where the force point is on the outer side, this effectively improves the compactness of the fuel cell stack. The depth of the base plate nut hole 72 is greater than the thickness of the sealing nut 8 to ensure that the sealing nut 8 can be completely embedded in the base plate nut hole 72. The outer side of the sealing nut 8 and the inner wall of the nut hole 72 in the base plate are fixed by welding (the solder fills the gap between the two and does not protrude from the lower side plane of the base plate 7, ensuring the flatness of the lower side of the base plate, which can serve as the sealing surface of the fuel cell stack), forming an inseparable whole.

[0036] like Figure 8As shown, the sealing nut 8 is cylindrical in shape, with an internal thread 82 on its upper side that matches the thread on the lower side of the insulating bolt 4, providing vertical tightening force for the fuel cell stack. The lower side of the sealing nut 8 has an internal hexagonal groove 81 for tightening with the insulating bolt 4 by rotating the sealing nut 8 with an Allen wrench.

[0037] The insulating bolt 4 and the sealing nut 8 mentioned above are separate components and are only used as examples, not as limitations. Designing the insulating bolt 4 and the sealing nut 8 as a single component (such as an integrated bolt with an internal hexagonal socket at the lower end) can still achieve the fastening function while simplifying the number of parts.

[0038] In this invention, the materials for the pressure plate 1, top plate 3, insulating bolt 4, connecting plate 6, bottom plate 7, and sealing nut 8 can all be high-temperature resistant alloys or ceramics, while the disc spring 2 and compression component 5 are made of high-temperature resistant metals. The pressure plate 1, top plate 3, connecting plate 6, and bottom plate 7 have the same external dimensions and are assembled by stacking them vertically.

[0039] In this invention, the disc springs 2 are conical discs, and their number and position correspond to the number of positioning slots 21 on the pressure plate. The upper outer diameter of the disc springs 2 is smaller than the inner diameter of the positioning slots 21 on the pressure plate (so that they can be completely placed inside the positioning slots), and its lower inner diameter is larger than the diameter of the positioning hole 31 on the top plate (so as not to affect the passage of the insulating bolts 4). After being compressed, the disc springs 2 generate a continuous elastic force, providing a stable vertical fastening force for the fuel cell stack; by utilizing their own elastic deformation, they adapt to the dimensional changes caused by temperature changes in the fuel cell stack (working in conjunction with the compression component 5 to achieve dynamic fastening, avoiding stress relief or overpressure caused by temperature changes).

[0040] In this invention, the insulating bolt 4 penetrates all stacked components, with a smooth cylindrical section in the middle. Its two ends have upper threads (matching the threaded hole 22 of the pressure plate) and lower threads (matching the internal thread 82 of the sealing nut), respectively, with consistent rotation directions. Through the threads at both ends, it engages with the pressure plate 1 and the sealing nut 8, providing a vertical tightening force. Specifically, the insulating bolt 4 passes through the bottom plate positioning hole 71, the connecting plate positioning hole 62, the compression member 5, the top plate positioning hole 31, the disc spring 2, and the pressure plate threaded hole 22 sequentially from bottom to top. Finally, it is tightened by the lower thread with the internal thread 82 of the sealing nut and the upper thread with the threaded hole 22 of the pressure plate, forming a tensile skeleton penetrating the fuel cell stack. It should be understood that the bottom plate positioning hole 71, the connecting plate positioning hole 62, the compression member 5, the top plate positioning hole 31, the disc spring 2, and the pressure plate threaded hole 22 mentioned above maintain axial alignment to ensure fastener assembly accuracy. The outer surface of the cylindrical section in the middle of the insulating bolt 4 has an insulating function. A ceramic insulating coating can be prepared by high-temperature spraying; or an insulating sleeve that fits into the cylindrical section can be fitted to prevent short circuits of live parts between repeated units (improving the safety of the fuel cell stack).

[0041] In addition, the upper and lower surfaces of the connecting plate 6 need to be processed by etching or machining to create flow channels for gas flow. The connecting plate 6 also has through-holes 63 that communicate with the flow channels. The bottom plate 7 also has through-holes 73 that communicate with the bottom plate. External gas flows with the repeating unit through the bottom plate 73. All the connecting plate 63 and bottom plate 73 of the repeating unit keep their axes aligned to ensure gas flow.

[0042] The assembly process of the integrated packaged solid oxide fuel cell of the present invention is briefly described below. First, the sealing nut 8 is embedded into the bottom plate nut hole 72 of the bottom plate 7 and welded in place (the solder does not protrude from the underside of the bottom plate); then, the connecting plate 6, the compression component 5, and conventional components (sealant, current collector, battery) are stacked sequentially from bottom to top, ensuring that the positioning hole 62 of the connecting plate is aligned with the positioning hole 71 of the bottom plate and the vent hole 63 of the connecting plate is aligned with the vent hole 73 of the bottom plate, and the stacking is repeated until the required number of units is reached; then, the top plate 3 is stacked on the connecting plate 6 of the topmost repeated unit, ensuring that the positioning hole 31 of the top plate is aligned with the positioning hole 62 of the connecting plate; corresponding to the top plate 3 on the upper side. Place the disc spring 2 in the correct position; then place the pressure plate 1 on top of the disc spring 2, ensuring that the pressure plate positioning groove 21 is aligned with the disc spring 2; from bottom to top, pass the insulating bolt 4 through the bottom plate positioning hole 71, the connecting plate positioning hole 62, the top plate positioning hole 31, and the disc spring 2, and finally tighten it with the threaded hole 22 of the pressure plate; finally, use an Allen wrench to rotate the insulating bolt 4 through the inner hexagonal groove 81 of the closed nut until the disc spring 2 and the compression component 5 produce a preset elastic deformation. At this time, the elastic force of the disc spring 2 is transmitted to the compression component 5, causing the arc-shaped thin plate 52 to produce elastic deformation, thus completing the assembly.

[0043] Thus, this invention transforms vertical tension into horizontal fastening force through the serrated outer contour 51 / inner contour 53 of the compression component 5 and the arc-shaped thin plate 52, solving the defect of existing technologies that rely solely on friction to resist shear. The disc spring 2 and the compression component 5 maintain elasticity in the range from room temperature to high temperature (up to 850°C, from room temperature such as 25°C to 850°C), automatically adapting to dimensional changes caused by thermal expansion and contraction of the fuel cell stack, solving the problems of loosening or overpressure in existing bolt fastening. Since all fasteners (insulating bolts 4, disc springs 2, and compression component 5) are built into the fuel cell stack without external protrusions, the problem of existing technologies occupying peripheral space and affecting integration is solved. The closed nut 8 is welded and fixed to the base plate 7, combined with the built-in fastener design, achieving a reliable anti-disassembly effect (the built-in fasteners themselves are difficult to directly touch and damage), allowing the fuel cell stack to be used as an independent component, solving the problem of existing fuel cell stacks being easily dispersed and requiring additional fastening mechanisms.

[0044] In summary, this invention provides tensile force through insulated bolts connected to the pressure plate and sealing nut, using this tensile force to compress the compression component and disc spring, generating elastic deformation, and simultaneously securing the fuel cell stack in both horizontal and vertical directions, thereby improving the stability of the fuel cell stack in all directions. Furthermore, it utilizes the elastic deformation maintained throughout the temperature range from room temperature to high temperature to achieve a dynamic matching function between the applied fastening force and the constantly changing dimensions caused by the thermal expansion of the fuel cell stack, ensuring that the device maintains high reliability in fuel cell stack fastening under temperature variations. In addition, the force-applying component is located inside the fuel cell stack, significantly improving the stack's compactness and facilitating stack stacking and combination. Moreover, the base plate and sealing nut are welded together to complete the integrated encapsulation of the fuel cell stack, improving its independence and sealing.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the invention. Various variations can be made to the above embodiments of the present invention. That is, all simple and equivalent changes and modifications made based on the claims and description of this invention fall within the protection scope of the claims. All aspects not described in detail in this invention are conventional technical content.

Claims

1. A one-piece packaged solid oxide fuel cell stack, characterized in that, include: The bottom plate (7), multiple sets of repeating units, top plate (3) and pressure plate (1) are stacked sequentially from bottom to top. Each set of repeating units includes a connecting plate (6) and a compression member (5) disposed on the upper side of the connecting plate (6). Disc spring (2), which is disposed between the top plate (3) and the pressure plate (1); A sealing nut (8) is fitted inside the base plate (7); An insulating bolt (4) passes through the pressure plate (1), disc spring (2), top plate (3), compression parts (5) of each repeating unit, connecting plate (6), and bottom plate (7) in sequence, and is fastened with the sealing nut (8) to form an independent and closed fuel cell stack unit. The tension provided by the insulating bolt (4) acts on the disc spring (2) and the compression member (5), the disc spring (2) generates a vertical tightening force, and the compression member (5) generates a horizontal tightening force.

2. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The disc spring (2) and the compression member (5) dynamically adapt to the dimensional changes caused by temperature changes in the integrated packaged solid oxide stack through elastic deformation.

3. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The connecting plate (6) is provided with a first stepped through hole structure, which includes a first upper section and a second lower section arranged concentrically. The diameter of the first section is larger than the diameter of the second section. The first section forms a connecting plate positioning groove (61), and the second section forms a connecting plate positioning hole (62). At least part of the compression member (5) is disposed in the connecting plate positioning groove (61), and the insulating bolt (4) passes through the connecting plate positioning hole (62).

4. The integrated packaged solid oxide fuel cell stack according to claim 3, characterized in that, The compression component (5) is generally annular, including an outer contour (51), an arc-shaped thin plate (52), and an inner contour (53). The arc-shaped thin plate (52) is a thin arc-shaped transition structure located in the middle and connecting the outer contour (51) and the inner contour (53). The outer contour (51) and the inner contour (53) of the compression component are both circumferentially arranged sawtooth-shaped, and the sawtooths are relatively independent. When not under force, the outer tangent circle diameter of the sawtooth of the outer contour (51) of the compression component is smaller than the inner diameter of the positioning groove (61) of the connecting plate, and the outer tangent circle diameter of the sawtooth of the inner contour (53) of the compression component is larger than the diameter of the central cylinder of the insulating bolt (4). The thickness of the compression component (5) is greater than the depth of the positioning groove (61) of the connecting plate.

5. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The pressure plate (1) is provided with a stepped blind hole structure, which includes a lower third section and an upper fourth section arranged concentrically. The diameter of the third section is larger than the diameter of the fourth section. The third section forms a pressure plate positioning groove (21), and the fourth section forms a pressure plate threaded hole (22). At least part of the disc spring (2) is provided in the pressure plate positioning groove (21), and the pressure plate threaded hole (22) is threaded with the upper side of the insulating bolt (4).

6. The integrated packaged solid oxide fuel cell stack according to claim 5, characterized in that, The stepped blind hole structures are evenly distributed at the four corners of the pressure plate (1) within the horizontal range of the pressure plate (1), and the distance from the center of each stepped blind hole structure to the center of the pressure plate (1) is equal.

7. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The base plate (7) is provided with a second stepped through hole structure, which includes a fifth section at the top and a sixth section at the bottom arranged concentrically. The diameter of the fifth section is smaller than that of the sixth section. The fifth section forms a base plate positioning hole (71), and the sixth section forms a base plate nut hole (72). The diameter of the base plate positioning hole (71) is larger than the diameter of the central cylinder of the insulating bolt (4). The inner diameter of the base plate nut hole (72) is larger than the outer diameter of the closed nut (8). The connection between the base plate nut hole (72) and the base plate positioning hole (71) forms an annular force-bearing surface (74), which is located inside the base plate (7).

8. The integrated packaged solid oxide fuel cell stack according to claim 7, characterized in that, The depth of the bottom plate nut hole (72) is greater than the thickness of the closing nut (8), and the closing nut (8) does not protrude from the lower side plane of the bottom plate (7); the closing nut (8) is fixed to the inner wall of the bottom plate nut hole (72) by welding.

9. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The insulating bolt (4) has a smooth cylindrical section in the middle. The insulating bolt (4) achieves its insulating function by spraying a ceramic insulating coating at high temperature or by fitting an insulating sleeve that fits into the cylindrical section.

10. The integrated packaged solid oxide fuel cell stack according to claim 1, characterized in that, The insulating bolt (4) and the sealing nut (8) are an integrated structure.

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