A clamping-pressure maintaining device and its use method and application

Abstract

The present invention relates to a clamping-pressure maintaining device and its use method and application. The device mainly includes a mounting seat 1, a base plate 2, a clamping mechanism 3, and a clamping force maintaining mechanism 4, wherein the clamping mechanism 3 is located between the mounting seat 1 and the base plate 2, and the fuel cell to be clamped 7 is located between the clamping mechanism 3 and the mounting seat 1. After the clamping mechanism 3 clamps the fuel cell, it is locked by the clamping force maintaining mechanism 4, thereby achieving uniform clamping of the product and the effect of maintaining the clamping force for a long time. The device solves the common problems of the existing fuel cell stack clamping mechanism, such as uneven distribution of clamping force and difficulty in maintaining clamping force under long-term work, and has many advantages such as simple structure, easy use, and good clamping effect. The use of this device can ensure that the clamping force is evenly distributed and maintained within the clamping force value range for optimal fuel cell performance, ensuring that the structure of the fuel cell assembly is more compact and the clamping force distribution is more uniform, ultimately improving the power density of the fuel cell.

Description

Technical Field

[0001] The present invention relates to the field of battery and mechanical technology, and in particular to a clamping-pressure maintaining device and a use method and application thereof. Background Art

[0002] As a secondary energy source, hydrogen not only boasts abundant reserves and a wide range of sources, but can also promote the development and utilization of various primary energy sources. Hydrogen-fueled proton exchange membrane fuel cells (PEMFCs) offer numerous advantages, including low noise, fast startup, high power density, no electrolyte corrosion, clean, carbon-free, pollution-free operation, and high energy conversion efficiency. They are considered the most promising alternative to traditional internal combustion engines for automotive power generation. They can also be used in distributed power generation systems, military equipment, and stationary power stations. Therefore, PEMFCs hold great potential for development. Vigorously promoting the development of their core technologies can effectively improve my country's energy structure and achieve "energy independence and controllability," which is of great significance to my country's environment, economy, society, and development.

[0003] PEMFC is composed of bipolar plates (BP), gas diffusion layers (GDL), catalyst layers (CL), proton exchange membranes (PEM), and other components. The bipolar plates are made by welding or gluing anode and cathode plates. The bipolar plates are the backbone of the stack, supporting the membrane electrode, collecting current, providing channels for reactant gas / coolant, and separating hydrogen and air. The membrane electrode is a five-in-one system consisting of a cathode / anode diffusion layer, a cathode / anode catalyst layer, and a proton exchange membrane. In actual applications, the PEMFC stack is assembled in series from several components. The manufacturing and assembly errors of each component accumulate during assembly and affect the overall stack error, thereby reducing the stack performance. Therefore, the stack packaging process determines the performance and cost of the stack.

[0004] During the assembly process of the fuel cell, the uneven clamping force applied by the clamping mechanism to the fuel cell may cause uneven surface pressure and internal stress distribution in some areas of the fuel cell assembly, thereby affecting the contact resistance of the fuel cell and the compression rate of the diffusion layer of the membrane electrode assembly, causing the fuel cell performance to deteriorate or even cause damage and leakage. In addition, in various application scenarios of fuel cells, the assembly clamping force may be greatly affected by frequent vibration environments. Although traditional clamping structures use spring washers and apply pre-tightening torque to reduce this effect, these structures are usually more complex and have more parts, which will also lead to an increase in the mass and volume of the fuel cell system. Therefore, there is an urgent need to develop a new fuel cell clamping mechanism and pressure maintenance device to better solve the above problems. Summary of the Invention

[0005] The primary purpose of this invention is to address the common issues of existing fuel cell clamping devices, such as complex structure, uneven clamping force distribution, and the inability to maintain the clamping force over a long period of time. This invention provides a novel clamping and pressure-maintaining device that applies a uniform clamping force to the fuel cell, with the clamping force being flexibly adjustable within a certain range for locking. This device reduces the contact resistance of the fuel cell and improves its performance.

[0006] To achieve the above object, the technical solutions adopted by the present invention are as follows:

[0007] A clamping-pressure maintaining device mainly includes a mounting seat 1, a base plate 2, a clamping mechanism 3, and a clamping force maintaining mechanism 4, wherein the clamping mechanism 3 is fixedly connected to the base plate 2 and is located between the mounting seat 1 and the base plate 2, and the object to be clamped 7 is located between the clamping mechanism 3 and the mounting seat 1. After the clamping mechanism 3 clamps the object to be clamped 7, it is locked by the clamping force maintaining mechanism 4, thereby achieving uniform clamping of the product and keeping the clamping force unchanged for a long time.

[0008] Furthermore, a support rod 6 is fixed to the mounting base 1. The support rod 6 passes through the object 7, the clamping mechanism 3, and the base plate 2, and is then fixedly connected to the nut 5, thereby evenly clamping and locking at least one set of objects 7 in place. The support rod not only provides fixed support, but also serves as positioning and guidance during assembly, and also serves to strengthen the structure and protect the fuel cell.

[0009] Furthermore, a plurality of support rods 6 are arranged at a certain distance on the edge of the contour of the mounting base 1 .

[0010] Furthermore, each support rod 6 has a cylindrical stepped shaft structure, comprising, from bottom to top, at least a first shaft section and a second shaft section, wherein the diameter of the first shaft section is larger than that of the second shaft section, and the end of the second shaft section is provided with threads that mate with the nut 5. The cylindrical stepped shaft can pass through the through-holes around the base plate 2, and the diameter of the second shaft section is larger than the diameter of the through-holes uniformly distributed around the base plate 2. Thus, the base plate 2 can be positioned and installed using the stepped shaft shoulder and the nut 5 installed on the first shaft section.

[0011] Furthermore, the length of the second shaft sections of the two diagonal support rods is greater than the length of the second shaft sections of the other support rods. The two diagonal support rods with slightly longer lengths mainly play a role in positioning and guiding during assembly.

[0012] Furthermore, a circular groove is provided on the outer edge of the base plate 2 to accommodate the support rod 6. A mounting hole for the fixed clamping mechanism 3 is provided in the center of the base plate 2. This mounting hole is composed of at least two through-holes of different diameters. The mounting hole for the fixed clamping mechanism 3 is divided into two sections, upper and lower, each with a different aperture diameter. The upper section has a smaller aperture, while the lower section has a larger aperture. The end surface formed by the two sections with different apertures can be used to axially position the bearing.

[0013] Furthermore, the clamping mechanism 3 includes an upper pressure plate 31, a bearing 32, a steel ball 33, and a lower pressure plate 34. The upper pressure plate 31 is mounted in the bearing 32, and the bearing 32 is fixed in the mounting hole in the center of the base plate 2. Gradient arc ramps are provided on the two opposite surfaces of the upper pressure plate 31 and the lower pressure plate 34. The steel ball 33 is located between the upper and lower gradient arc ramps and can roll along the ramp, thereby making it possible to conveniently and quickly continuously adjust the clamping force.

[0014] Furthermore, the upper pressure plate 31 has a stepped shaft structure, including at least a first shaft segment 31b, a second shaft segment 31d, a third shaft segment 31e, and a fourth shaft segment 31f from top to bottom, and the diameter of each shaft segment gradually increases.

[0015] Furthermore, a groove 31 a for rotationally adjusting the clamping force is provided on the upper end surface of the first shaft segment 31 b , and a keyway 31 c for installing a connecting key 42 is provided on the side surface of the first shaft segment 31 b .

[0016] Furthermore, the outer cylindrical surface of the second shaft segment 31d contacts and is fixedly connected to the inner ring of the bearing 32, and the shoulder of the third shaft segment 31e contacts and is fixedly connected to the side surface of the inner ring of the bearing 32, thereby limiting the displacement of the upper pressure plate 31; the fourth shaft segment 31f and the lower pressure plate 34 transmit the clamping force evenly to the object to be clamped 7 through the steel ball 33 and the gradual arc ramp combination structure.

[0017] Furthermore, the gradually changing arc ramps on the upper pressure plate 31 and the lower pressure plate 34 are composed of 2-4 gradually changing arc grooves arranged discontinuously along the circumference; the number of steel balls 33 is the same as the number of gradually changing arc grooves, which is also 2-4.

[0018] Furthermore, the slope of the gradual arc-shaped ramp is 5%-50%, and the diameters of the steel balls are the same and are no larger than the cross-sectional profile diameter of the gradual arc-shaped ramp, preferably equal to.

[0019] Furthermore, a plurality of through holes are provided on the contour edge of the lower pressure plate 34 for the support rod 6 to pass through, thereby connecting and fixing the clamping mechanism 3 in series with the mounting seat 1 , the object to be clamped 7 , and the base plate 2 .

[0020] Furthermore, the clamping force maintaining mechanism 4 includes a ratchet 41, a pawl 43, and an elastic element 44. A through hole is provided on the ratchet 41. The upper pressure plate 31 passes through the through hole and is fixedly connected to the ratchet 41 and rotates with it. The pawl 43 is fixed on the base plate 2 and fits with the tooth surface of the ratchet 41. One end of the elastic element 44 is fixed on the base plate 2 and the other end is connected to the pawl 43 and tightens it.

[0021] Furthermore, the elastic element 44 is specifically a tension spring.

[0022] Furthermore, the upper pressure plate 31 is fixedly connected to the ratchet 41 via a connecting key 42 .

[0023] Furthermore, the projection shapes of the mounting seat 1, base plate 2, lower pressure plate 34, and object to be clamped 7 on the horizontal plane are the same, all selected from one of circular and rectangular; the projection of the fourth shaft segment 31f of the upper pressure plate 31 on the horizontal plane is circular.

[0024] Another object of the present invention is to provide a method for using the above-mentioned clamping-pressure maintaining device, which includes the following steps: (a) first, the object to be clamped 7, the clamping mechanism 3, and the base plate 2 are sequentially mounted on the support rod 6, and then the nut 5 is tightened to complete the initial clamping; (b) the upper pressure plate 31 of the clamping mechanism 3 is rotated to drive the steel ball 33 to roll in the gradient arc ramp, and the steel ball 33 squeezes the lower pressure plate 34, and the lower pressure plate 34 squeezes the object to be clamped 7 to complete the secondary clamping. At the same time, the ratchet 41 also rotates synchronously with the upper pressure plate 31 and is locked by the pawl 43, thereby achieving the locking of the clamping force.

[0025] Furthermore, the method further includes step (c): loosening the ratchet 43 and rotating the upper pressure plate 31 in the opposite direction, thereby reducing or releasing the clamping force.

[0026] A third object of the present invention is to provide applications of the clamping-pressure maintaining device in fuel cells, electrolyzer hydrogen production devices, and the like.

[0027] The present invention aims to address the problems commonly found in existing fuel cell stack clamping mechanisms, such as uneven clamping force distribution and difficulty maintaining clamping force over long periods of operation. Uniform clamping of the fuel cell is achieved through a support column-nut combination, a steel ball-gradually curved ramp combination, and a base plate-upper pressure plate-lower pressure plate combination. A ratchet-pawl-tension spring combination ensures that the clamping force of the fuel cell remains constant over the long term. This device offers numerous advantages, including a simple structure, ease of use, and effective clamping. When used in the assembly of fuel cell stacks or single cells, it ensures uniform distribution of clamping force and maintains it within the optimal clamping force range for fuel cell performance, ensuring that the stress and surface pressure of the sealing assembly reach the operating pressure. Ultimately, this results in a more compact fuel cell assembly structure and a more uniform distribution of clamping force, helping to increase the power density of the fuel cell and prevent loosening of the fuel cell.

[0028] Compared with existing similar products, the beneficial effects of the present invention are mainly reflected in the following aspects:

[0029] (1) In the clamping and pressure maintaining device provided by the present invention, each component is provided with a positioning hole and a positioning groove, which facilitates the rapid installation and positioning of the fuel cell assembly, not only significantly reducing the tolerance of the fuel cell during the assembly process, but also improving the installation efficiency of the fuel cell assembly;

[0030] (2) The clamping-pressure maintaining device provided by the present invention adopts a ball cam mechanism to amplify the input torque, cleverly converting the rotational motion of the input torque into vertical movement of the upper pressure plate. The upper pressure plate applies a uniform clamping force to the fuel cell stack, thereby avoiding problems such as increased contact resistance and decreased fuel cell performance caused by uneven distribution of fuel cell clamping force. The improvement of the fuel cell clamping state in turn increases its power density.

[0031] (3) The clamping-pressure maintaining device provided by the present invention limits the unidirectional rotation of the fuel cell through a ratchet mechanism, so that the clamping force acting on the fuel cell stack is always maintained within the rated value range, preventing the clamping mechanism from loosening due to vibration during use, thereby improving the service life and durability of the fuel cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a three-dimensional schematic diagram of the device of the present invention;

[0033] Figure 2 It is a front view of the device of the present invention;

[0034] Figure 3 Schematic diagram of the structure of the clamping mechanism 3 in the device of the present invention;

[0035] Figure 4 Schematic diagram of the structure of the clamping force maintaining mechanism 4 in the device of the present invention;

[0036] Figure 5 It is a structural schematic diagram of the upper pressure plate in the device of the present invention.

[0037] Among them, 1-mounting seat, 2-base plate, 3-clamping mechanism, 4-clamping force maintaining mechanism, 5-nut, 6-support rod, 7-object to be clamped; 31-upper pressure plate, 32-bearing, 33-steel ball, 34-lower pressure plate; 31a-groove, 31b-first shaft segment, 31c-keyway, 31d-second shaft segment, 31e-third shaft segment, 31f-fourth shaft segment; 41-ratchet, 42-connecting key, 43-pawl, 44-elastic element. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to fully understand the technical solutions and beneficial effects of the present invention, further description will be given below in conjunction with specific embodiments and drawings.

[0039] Cost and lifespan are two major issues facing PEMFC. An excellent stack assembly solution can reduce fuel cell costs and improve fuel cell lifespan and power generation performance. Currently, the clamping force on fuel cells during clamping may be unevenly distributed due to design defects in the assembly method and clamping mechanism. In severe cases, air leakage, water leakage and other adverse phenomena may occur. Therefore, the present invention has designed and developed the following solution: Figure 1-5 The fuel cell clamping mechanism shown improves the uniformity of the fuel cell clamping force by changing the way the clamping force is applied, thereby reducing the contact resistance of the fuel cell and improving the performance of the fuel cell.

[0040] The clamping-pressure maintaining device comprises, from bottom to top, a mounting plate 1, a fuel cell stack (i.e., the object to be clamped 7), a clamping mechanism 3, a base plate 2, and a clamping force maintaining mechanism 4, wherein the clamping mechanism 3 comprises an upper pressure plate 31, a bearing 32, three steel balls 33, and a lower pressure plate 34; the clamping force maintaining mechanism 4 comprises a ratchet 41 that rotates synchronously with the upper pressure plate 31, a pawl 43 that engages with the ratchet 41 and limits its unidirectional rotation, and an elastic element 44 (i.e., a tension spring) that tightens the ratchet to keep it in a locked state.

[0041] The mounting base 1 is a rectangular metal plate with rounded corners, and a plurality of support rods 6 perpendicular to the base plane are evenly distributed on its four sides at a certain distance. The support rod 6 is in the shape of a stepped shaft with a thickness at the bottom and a thickness at the top, and has a first shaft section and a second shaft section from bottom to top, wherein the first shaft section is a round shaft with a smooth surface, and the second shaft section has a threaded surface. Among the many support rods, the second shaft sections of the two support rods in diagonal positions are longer than those of the other support rods. This design is mainly to match the circular groove corresponding to the lower surface of the base plate 2, so that the base plate 2 can be positioned during assembly, ensuring that the shoulder from the second shaft section to the first shaft section is in contact with the lower surface of the base plate 2, and limiting the downward displacement of the base plate 2. After assembly is in place, tighten the nut 5 on the threaded section of the second shaft section of the support rod 6 to complete the fastening of the base plate 2.

[0042] Base plate 2 is also a rectangular metal plate with rounded corners. Through-holes are distributed uniformly along its four edges. Support rods 6 pass through these through-holes and are fixedly connected to nuts 5. Accordingly, circular grooves are provided in base plate 2 at the through-holes corresponding to the two positioning support rods (the aforementioned diagonal holes) in mounting base 1, primarily for positioning base plate 2. Furthermore, a larger through-hole is provided in the center of base plate 2, primarily for securing and mounting clamping mechanism 3.

[0043] The upper platen 31 of the clamping mechanism 3 has a ⊥-shaped structure and, from top to bottom, comprises a first shaft segment 31b, a second shaft segment 31d, a third shaft segment 31e, and a fourth shaft segment 31f. A rectangular groove 31a is provided on the upper end surface of the first shaft segment 31b of the upper platen 31. This groove 31a connects to a torque-transmitting device (such as a motor or torque wrench). Rotation of the groove 31a and the upper platen 31 is converted into downward movement of the lower platen 34, thereby applying a clamping force to the fuel cell. A keyway 31c is provided on the side of the first shaft segment 31b. A connecting key 42, which is fixedly connected to the ratchet 41, is installed in this keyway 31c, thereby securely connecting the upper platen 31 to the ratchet 41 of the clamping force maintaining mechanism 4. The outer circumference of the second shaft segment 31d contacts the inner race of the bearing 32, and the bearing is axially positioned by the shoulders of the second and third shaft segments 31d and 31e. The third shaft segment 31e serves as a transition between the second shaft segment 31d and the fourth shaft segment 31f, enhancing component strength and preventing friction caused by direct contact between the outer ring of the bearing 32 and the upper pressure plate 31. The lower end surface of the fourth shaft segment 31f and the upper end surface of the lower pressure plate 34 are both machined with a gradually curved ramp. Multiple steel balls 33 are mounted between them, applying a uniform pressure to the lower pressure plate 34.

[0044] The bearing 32 of the clamping mechanism 3 is fixedly mounted in a through-hole at the center of the base plate 2. The outer ring of the bearing contacts the inner wall of the through-hole and remains stationary. The inner ring of the bearing contacts the outer circumference of the second shaft segment 31d of the upper pressure plate 31 and the shoulder of the second to third shaft segments. The inner ring of the bearing can rotate with the upper pressure plate 31. The lower pressure plate 34 of the clamping mechanism is a rectangular metal plate similar to the mounting base 1 or base plate 2. It is also uniformly distributed with through-holes on its four sides. The support rod 6 passes through these through-holes and then through the base plate 2, allowing the base plate 2 to move axially along the support rod 6 to accommodate different numbers of fuel cell stacks. As previously mentioned, a gradually curved ramp (also known as a ball ramp) is provided at the center of the circular bottom surface of the upper pressure plate 31 and the upper surface of the lower pressure plate 34, and is equipped with a steel ball 33. When the fuel cell is compressed, the steel ball is located at the deepest point of the gradually curved ramp of the upper and lower pressure plates 31 and 34, and the upper and lower surfaces of the steel ball 33 are in close contact with the two ramps respectively.

[0045] The clamping force maintaining mechanism 4 is fixedly mounted on the first shaft section 31b of the upper pressure plate 31 and the upper end surface of the base plate 2. The specific connection method is as follows: the upper pressure plate 31 passes through and is fixed in the through hole at the center of the base plate 2. The connecting key 42 is installed in the keyway 31c on the side of the first shaft section 31b of the upper pressure plate 31. The ratchet 41 is fixedly connected to the upper pressure plate 31 through the connecting key 42. The pawl 43 is installed on the cylinder on the upper end surface of the base plate 2. One end of the elastic element 44 is connected to the pawl 43 to tighten it, and the other end is connected to another cylinder on the base plate 2. The pawl 43 is pressed by the tension of the elastic element 44 and engages with the tooth surface of the ratchet 41, thereby limiting the unidirectional rotation of the ratchet 41.

[0046] The operation process of the clamping-pressure maintaining device is as follows: the fuel cell (i.e., the object to be clamped 7) and the clamping mechanism 3 are assembled in sequence and the nut 5 is tightened, a torque (rotation) is applied to the upper pressure plate 31 to make it rotate together with the ratchet 41, and the ball ramp mechanism on the upper pressure plate 31 rotates relative to the lower pressure plate 34. The steel ball 33 in the ball ramp produces a downward displacement due to the gradual decrease in the depth of the ball ramp. The support rod 6 passing through the through hole around the lower pressure plate 34 limits the relative rotation so that it can only produce a downward displacement. The displacement of the steel ball 33 acting on the ball ramp mechanism of the lower pressure plate 34 is converted into a uniform downward force on the lower pressure plate 34, thereby clamping the fuel cell stack together with the mounting base 1; at the same time, the ratchet 41 rotates together with the upper pressure plate 31, and the ratchet 41 produces a displacement relative to the pawl 43 during the rotation. When the rated clamping force is reached, the upper pressure plate 31 stops rotating, and the ratchet 41 cannot produce a reverse rotation under the action of the pawl 43, thereby locking and maintaining the clamping force of the fuel cell stack.

Claims

1. A clamping-pressure maintaining device, characterized in that: The device mainly comprises a mounting seat (1), a base plate (2), a clamping mechanism (3) and a clamping force maintaining mechanism (4); the clamping mechanism (3) comprises an upper pressure plate (31), a steel ball (33) and a lower pressure plate (34); gradient arc ramps are provided on two opposite surfaces of the upper pressure plate (31) and the lower pressure plate (34); the steel ball (33) is provided between the upper and lower gradient arc ramps between the upper pressure plate (31) and the lower pressure plate (34) and can roll along the ramps; the clamping force maintaining mechanism (4) comprises an upper pressure plate (31), a steel ball (33) and a lower pressure plate (34); the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; ... upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure plate (34) are provided with gradient arc ramps; the upper pressure plate (31) and the lower pressure The holding mechanism (4) comprises a ratchet (41) and a pawl (43); the upper pressure plate (31) is fixedly connected to the ratchet (41) and rotates therewith; the pawl (43) is fixed on the base plate (2) and fits with the tooth surface of the ratchet (41); the clamping mechanism (3) is arranged between the mounting seat (1) and the base plate (2); the object to be clamped (7) is arranged between the clamping mechanism (3) and the mounting seat (1); the clamping mechanism (3) clamps the object to be clamped (7) and is locked by the clamping force holding mechanism (4).

2. The device according to claim 1, wherein: A plurality of support rods (6) are fixed on the mounting seat (1), and the support rods (6) sequentially pass through the object to be clamped (7), the clamping mechanism (3), and the through holes on the base plate (2) and are fixedly connected to the nuts (5).

3. The device according to claim 1, wherein: The clamping mechanism (3) includes a bearing (32), the upper pressure plate (31) is sleeved in the bearing (32), and the bearing (32) is fixed in a mounting hole at the center of the base plate (2).

4. The device according to claim 1, wherein: The upper pressure plate (31) has a stepped shaft structure, comprising at least a first shaft section (31b), a second shaft section (31d), a third shaft section (31e) and a fourth shaft section (31f) from top to bottom, and the diameter of each shaft section gradually increases.

5. The device according to claim 4, characterized in that: A groove (31a) is provided on the upper end surface of the first shaft section (31b), a keyway (31c) is provided on the side surface of the first shaft section (31b), the outer cylindrical surface of the second shaft section (31d) contacts and is fixedly connected to the inner ring of the bearing (32), the shoulder of the third shaft section (31e) contacts and is fixedly connected to the side surface of the inner ring of the bearing (32), and the fourth shaft section (31f) and the lower pressure plate (34) uniformly transmit the clamping force to the object to be clamped (7) through the steel ball (33) and the gradually changing arc ramp.

6. The device according to claim 1, wherein: The gradually changing arc-shaped ramps on the upper pressing plate (31) and the lower pressing plate (34) are composed of multiple sections of gradually changing arc-shaped grooves arranged discontinuously along the circumference, and the slope of the gradually changing arc-shaped ramps is 5%-50%; the number of steel balls (33) is the same as the number of the gradually changing arc-shaped grooves, and the diameters of the steel balls are the same and are not greater than the cross-sectional profile diameter of the gradually changing arc-shaped ramps.

7. The device according to claim 1, wherein: The clamping force holding mechanism (4) further comprises a connecting key (42) and an elastic element (44). A through hole is provided on the ratchet (41). The upper pressure plate (31) passes through the through hole and is fixedly connected to the ratchet (41) via the connecting key (42) and rotates with the ratchet (41). One end of the elastic element (44) is fixed to the base plate (2), and the other end is connected to the ratchet (43) and tightens it.

8. The method for using the clamping-pressure maintaining device according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: (a) firstly, fixing the object to be clamped (7), the clamping mechanism (3), and the base plate (2) in sequence to complete the initial clamping; (b) rotating the upper pressure plate (31) of the clamping mechanism (3) to drive the steel ball (33) to roll in the gradually changing arc-shaped ramp, the steel ball (33) presses the lower pressure plate (34), and the lower pressure plate (34) presses the object to be clamped (7) to complete the secondary clamping; at the same time, the ratchet (41) also rotates synchronously with the upper pressure plate (31) and is locked by the ratchet pawl (43), thereby realizing the locking of the clamping force.

9. The method according to claim 8, wherein The method further comprises step (c): loosening the ratchet (43) and rotating the upper pressure plate (31) in the opposite direction, thereby reducing or releasing the clamping force.

10. Use of the clamping-pressure maintaining device according to any one of claims 1 to 7 in a fuel cell or electrolyzer hydrogen production device.

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