A stress-compensated flexible graphite plate cleaning device and method of use thereof

Abstract

The present application relates to a kind of stress-compensated flexible graphite plate cleaning device and its use method, the device includes solidification unit and stress compensation component, the upper wire mesh screen (2) of the solidification unit and the lower wire mesh screen (4), the upper wire mesh (22) of the upper wire mesh screen (2) is arranged between the lower wire mesh (42) of the lower wire mesh screen (4), flexible graphite plate (3), the stress compensation component is electromagnet (1), the electromagnet (1) is suspended in the outside of upper wire mesh (22);The material of the upper wire mesh (22) is metastable austenitic stainless steel or stable austenitic stainless steel, the material of the lower wire mesh (42) is ferritic stainless steel;The outside surface of the upper wire mesh (22) and the lower wire mesh (42) is fixed with upper frame (21) and lower frame (41). Compared with prior art, the present application realizes stress compensation in the case where no reinforcing rib design is realized in the screen plate, and the service time of high-tension screen plate is greatly improved.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology and relates to a stress-compensated flexible graphite electrode cleaning device and its usage method. Background Technology

[0002] Flexible graphite, due to its excellent formability, thermal conductivity, electrical conductivity, and low price, is considered the most likely material for mass production and application in fuel cell electrode plates, attracting numerous companies and research institutions to conduct research and development on flexible graphite electrode plates. In traditional processes, the cleaning baskets used after impregnation are usually in the form of slats, with a large number of hollow parts. This design can easily lead to damage to the electrode plates during the cleaning process.

[0003] Therefore, a pair of high-tensile stainless steel mesh plates can be used to constrain the impregnated single electrode plate for cleaning. It is well known that the tension of the wire mesh decreases due to stress relaxation. To compensate for this tension, a conventional approach is to use structural design to add reinforcing ribs to the back of the mesh plate to reduce the impact of stress relaxation. However, using reinforcing ribs increases the contact area between the electrode plate and the ribs, causing resin to precipitate and solidify on the electrode plate surface during water bath curing, resulting in the electrode plate becoming unusable.

[0004] Patent CN114927702A discloses a device for cleaning residual resin from molded graphite plates in fuel cells. The device includes a hot water tank, an electric hoist, an impregnation basket, and a push-pull module. The impregnation basket is suspended above the hot water tank by the electric hoist and is submerged in the hot water tank under the action of the hoist. The push-pull module includes a motor, a crank, and a push rod. The motor is located on one side of the hot water tank, the crank is mounted on the motor's output shaft, and one end of the push rod is connected to the crank, while the other end is connected to the electric hoist's cable. However, the cleaning basket in this patent provides no constraint on the electrode plates. In the cleaning state, the resin on the electrode plates has not yet solidified, making the plates extremely soft and prone to damage.

[0005] Patent CN115106319A discloses a cleaning fixture and method for flexible graphite electrode plates in fuel cells, including a fixed frame and multiple detachable perforated mesh frames disposed within the fixed frame for fixing the flexible graphite electrode plates. Each perforated mesh frame includes a pair of parallel perforated mesh plates, multiple cleaning through holes formed on the sides of the perforated mesh plates, and limiting spacers located between the perforated mesh plates and at their edges. The flexible graphite electrode plate is clamped and fixed between the pair of perforated mesh plates, and its perimeter is limited and fixed by the limiting spacers. However, the mesh plates in this patent are made of stainless steel, aluminum alloy, or plastic with a thickness of 1-3mm. Stainless steel or aluminum alloy mesh plates are heavy, and while plastic mesh plates offer significant weight reduction, their reliability is low and they are easily damaged. Furthermore, the perforation method in this patent cannot uniformly constrain the electrode plate surface, and the perforations can easily damage the electrode plate in the uncured resin state. Summary of the Invention

[0006] The purpose of this invention is to overcome at least one defect of the prior art by providing a stress-compensated flexible graphite electrode cleaning device and its usage method. This invention enables stress compensation of the mesh plate without reinforcing rib design, thereby significantly improving the service life of high-tensile mesh plates.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] One of the technical solutions of the present invention is to provide a stress-compensated flexible graphite electrode cleaning device. The device includes a curing unit and a stress compensation component. The curing unit is a pair of high-tensile stainless steel mesh plates with the same mesh count and tension, including an upper mesh plate and a lower mesh plate. The flexible graphite electrode plate to be cleaned after being impregnated is placed between the upper mesh of the upper mesh plate and the lower mesh of the lower mesh plate. The curing unit is fixed by an edge locking structure. The stress compensation component is an electromagnet, which is suspended outside the upper mesh.

[0009] Furthermore, the upper wire mesh material is metastable austenitic stainless steel or stable austenitic stainless steel, and the lower wire mesh material is ferritic stainless steel.

[0010] Furthermore, the metastable austenitic stainless steel includes 301, 301L, 304, 304L, 316 or 316L, the stable austenitic stainless steel includes 310 or 310L, and the ferritic stainless steel includes 430 or 441.

[0011] Furthermore, the upper and lower wire meshes have a mesh count of 50-200 and a tension of 15-40N.

[0012] Furthermore, the upper and lower borders are fixed to the outer sides of the upper and lower wire mesh.

[0013] Furthermore, the upper and lower frame are made of aluminum alloy or stainless steel, with a thickness of 1-30mm and a width of 5-50mm.

[0014] As a preferred technical solution, the inner dimensions of the frame depend on the size of the constrained flexible graphite electrode, with a length of 400-600mm and a width of 200-350mm.

[0015] Furthermore, the lower surface of the electromagnet is 100-500mm away from the contact surface between the upper wire mesh and the upper frame. The electromagnet fixing area is characterized by an austenitic stainless steel upper wire mesh and a flexible graphite electrode plate between the contact surface between the electromagnet and the lower frame of the ferritic stainless steel lower wire mesh, so as to ensure that the ferritic stainless steel lower wire mesh is subjected to a magnetic force applied in the direction of the flexible graphite electrode plate.

[0016] Furthermore, the magnetic field strength of the electromagnet is 0.05-0.8T.

[0017] One of the technical solutions of the present invention is to provide a method for using a stress-compensated flexible graphite electrode cleaning device, the method comprising the following steps:

[0018] (1) Fix the upper wire mesh onto the upper frame to prepare the upper wire mesh plate;

[0019] (2) Using the same process, fix the lower wire mesh with the same mesh number as in step 1 onto the lower frame to prepare the lower wire mesh plate, ensuring that the wire mesh tension is the same as in step 2;

[0020] (3) Place a piece of lower wire mesh with the lower frame facing down, and place a piece of flexible graphite electrode plate that has been soaked and is to be cleaned flat on top of the lower wire mesh. Then, cover the upper surface of the flexible graphite electrode plate with another piece of upper wire mesh with the upper frame facing up. The above parts form a curing unit, and the curing unit is fixed by the edge locking structure.

[0021] (4) Suspend the electromagnet above the contact surface between the upper wire mesh and the upper frame, and form a cleaning device with the curing unit. Adjust the magnetic field strength of the electromagnet to control the stress compensation on the lower wire mesh.

[0022] (5) Place the flexible graphite electrode plate after the curing unit is impregnated in water for cleaning, keeping the liquid level higher than the upper surface of the curing unit, and the electromagnet above the liquid surface without contacting the liquid surface. After cleaning, take out the flexible graphite electrode plate.

[0023] As a preferred technical solution, the wire mesh and the frame are fixed by adhesive bonding, welding, or pressing.

[0024] Furthermore, the distance between the liquid level and the upper surface of the curing unit is 100-200mm, and the cleaning time is 5-30min.

[0025] Because austenite and ε-martensite are paramagnetic phases, while α'-martensite and ferrite are ferromagnetic phases; and because stable austenitic stainless steel is entirely austenite, while metastable austenitic stainless steel contains ε-martensite and α'-martensite generated by cold working, but in extremely low amounts; therefore, electromagnets have no effect on austenitic stainless steel wire mesh, have minimal effect on metastable austenitic stainless steel, but produce a significant magnetic force on ferritic stainless steel. Using a curing assembly for stress-compensated cleaning of flexible graphite plates can meet the long-term service conditions of tooling components, significantly extending their service life.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] (1) This invention utilizes the paramagnetic properties of austenitic stainless steel wire mesh and the ferromagnetic properties of ferritic stainless steel wire mesh to compensate for stress in the metal wire mesh by using magnetic force, thereby preventing significant stress relaxation of the mesh plate during long-term water bath operation.

[0028] (2) The present invention uses a non-contact stress compensation method, which avoids the stress compensation design of traditional reinforcing ribs and avoids the surface resin precipitation caused by the contact between the electrode plate and the reinforcing rib, which would lead to the scrapping of the electrode plate. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the stress-compensated flexible graphite electrode cleaning device in an embodiment of the present invention.

[0030] Explanation of markings in the diagram:

[0031] 1—Electromagnet, 2—Upper wire mesh plate, 21—Upper frame, 22—Upper wire mesh, 3—Flexible graphite electrode plate, 4—Lower wire mesh plate, 41—Lower frame, 42—Lower wire mesh. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0033] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0034] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0035] Example:

[0036] A stress-compensated flexible graphite plate cleaning device and its usage method, such as Figure 1 As shown, the desired cleaning process involves using a curing unit combined with a stress compensation component to clean a flexible graphite electrode plate 3 that has been impregnated with a thickness of 1 mm, a length of 350 mm, and a width of 180 mm. The specific steps are as follows:

[0037] Step 1: Use 316L metastable austenitic stainless steel wire mesh 22 with a mesh size of 50 mesh and 6063 aluminum alloy with a thickness of 20mm, a width of 30mm, an inner length of 500mm, and an inner width of 300mm as the upper frame 21. Fix the wire mesh to the frame by pressing to make an austenitic stainless steel wire mesh plate 2 with a tension of 35N.

[0038] Step 2: Use 430 ferritic stainless steel lower wire mesh 42 with a mesh size of 50 mesh and 6063 aluminum alloy with a thickness of 20mm, a width of 30mm, an inner length of 500mm, and an inner width of 300mm as the lower frame 41. Fix the wire mesh to the frame by pressing to make a ferritic stainless steel lower wire mesh plate 4 with a tension of 35N.

[0039] Step 3: Place the front of the austenitic stainless steel upper wire mesh plate 2 opposite to the front of the ferritic stainless steel lower wire mesh plate 4 (non-frame bonding surface), and place the flexible graphite electrode plate 3 to be cleaned in the center. The above parts form a curing unit, and the curing unit is locked with a locking nut.

[0040] Step 4: Fix electromagnet 1 as a stress compensation component at a distance of 350mm from the back (frame bonding surface) of the austenitic stainless steel upper wire mesh plate 2 on the lower surface of electromagnet 1 to form a cleaning device. Turn on the power and control the magnetic field strength of the electromagnet to 0.3T.

[0041] Step 5: Place the curing unit in deionized water, keeping the liquid level 120mm above the upper surface of the curing unit. Electromagnet 1 should be above the liquid surface without contacting it. After cleaning for 15 minutes, remove the flexible graphite plate.

[0042] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A stress-compensated flexible graphite electrode cleaning device, characterized in that, The device includes a curing unit and a stress compensation component. The curing unit includes an upper wire mesh plate (2) and a lower wire mesh plate (4). A flexible graphite electrode plate (3) is provided between the upper wire mesh (22) of the upper wire mesh plate (2) and the lower wire mesh (42) of the lower wire mesh plate (4). The stress compensation component is an electromagnet (1), which is suspended outside the upper wire mesh (22). The upper wire mesh (22) is made of metastable austenitic stainless steel or stable austenitic stainless steel, and the lower wire mesh (42) is made of ferritic stainless steel.

2. The stress-compensated flexible graphite electrode cleaning device according to claim 1, characterized in that, The metastable austenitic stainless steel includes 301, 301L, 304, 304L, 316 or 316L, the stable austenitic stainless steel includes 310 or 310L, and the ferritic stainless steel includes 430 or 441.

3. The stress-compensated flexible graphite electrode cleaning device according to claim 1, characterized in that, The upper wire mesh (22) and lower wire mesh (42) have a mesh count of 50-200 and a tension of 15-40 N.

4. The stress-compensated flexible graphite electrode cleaning device according to claim 1, characterized in that, The upper frame (21) and lower frame (41) are fixed to the outer sides of the upper wire mesh (22) and lower wire mesh (42).

5. The stress-compensated flexible graphite electrode cleaning device according to claim 4, characterized in that, The upper frame (21) and lower frame (41) are made of aluminum alloy or stainless steel, with a thickness of 1-30 mm and a width of 5-50 mm.

6. The stress-compensated flexible graphite electrode cleaning device according to claim 1, characterized in that, The electromagnet (1) is 100-500 mm away from the upper wire mesh (22).

7. The stress-compensated flexible graphite electrode cleaning device according to claim 1, characterized in that, The magnetic field strength of the electromagnet (1) is 0.05-0.8 T.

8. A method of using a stress-compensated flexible graphite electrode cleaning device as described in any one of claims 1 to 7, characterized in that, The method includes the following steps: (1) Fix the upper wire mesh (22) onto the upper frame (21) to prepare the upper wire mesh plate (2); (2) Fix the lower wire mesh (42) onto the lower frame (41) to prepare the lower wire mesh plate (4). (3) Place the lower wire mesh (42) with the lower frame (41) facing downwards, and place the flexible graphite electrode plate (3) flat on top of the lower wire mesh (42), and then cover the upper surface of the flexible graphite electrode plate (3) with the upper wire mesh (22) and the upper frame (21) facing upwards. (4) Suspend the electromagnet (1) above the contact surface between the upper wire mesh (22) and the upper frame (21), and adjust the magnetic field strength of the electromagnet (1); (5) Place the curing unit with the flexible graphite electrode plate (3) in water for cleaning, keeping the liquid level higher than the upper surface of the curing unit. After cleaning, remove the flexible graphite electrode plate (3).

9. The method of using the stress-compensated flexible graphite electrode cleaning device according to claim 8, characterized in that, The liquid level is 100-200 mm above the upper surface of the curing unit, and the cleaning time is 5-30 min.

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