A method for batch production of PEMFC flexible graphite bipolar plates by impregnation

Abstract

The application discloses a kind of batch preparation PEMFC flexible graphite bipolar plate impregnation method, including in the impregnation tank into the graphite bipolar plate to be impregnated processing;Resin solution is stored in liquid storage tank, by impregnation pipeline and reflux pipeline respectively each other communication liquid storage tank and impregnation tank;Vacuum pump is used to carry out vacuumizing treatment to impregnation tank;Open impregnation pipeline, close reflux pipeline, resin solution in liquid storage tank enters impregnation tank under the action of negative pressure in impregnation tank, and close impregnation pipeline after impregnation tank;By air compressor, gas is pumped into impregnation tank, so that the pressure in impregnation tank reaches preset value, and resin impregnation process of graphite bipolar plate is carried out;After completing resin impregnation of graphite bipolar plate, open reflux pipeline, and resin solution is refluxed to liquid storage tank under the action of gas pressure in impregnation tank;The finished product of graphite bipolar plate after impregnation is taken out.The application can reduce the impregnation time of flexible graphite bipolar plate, and help to realize the resin efficient impregnation of PEMFC flexible graphite bipolar plate.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of graphite bipolar plate preparation, and particularly relates to a batch preparation method of a PEMFC flexible graphite bipolar plate. BACKGROUND

[0002] The bipolar plate is an important component of the PEMFC, and its main functions include isolating and distributing oxidants and fuels, conducting current, supporting the membrane electrode, adjusting the temperature inside the stack, and the like, and needs to meet the performance requirements of electric conductivity, bending strength, corrosion resistance and the like.

[0003] The fuel cell bipolar plate is mainly made of graphite and metal materials. The mechanical properties, electric conductivity and thermal conductivity of the metal bipolar plate are very excellent, but the corrosion resistance is poor, which seriously restricts the practical application of the metal bipolar plate. The graphite bipolar plate mainly includes a hard graphite bipolar plate prepared by mechanical carving and a flexible graphite bipolar plate prepared by molding and impregnation.

[0004] At present, the flexible graphite bipolar plate is prepared by molding and impregnation. The flexible graphite plate raw material is molded by a press machine, then impregnated with resin by an impregnation device, and then subjected to processes such as cleaning, curing, drying and bipolar plate bonding.

[0005] In the production process of the PEMFC flexible graphite bipolar plate, the impregnation time is relatively long, and it usually takes several hours or even longer to completely impregnate the resin into the pores of the flexible graphite bipolar plate.

[0006] Therefore, the existing impregnation process of the graphite bipolar plate is not only time-consuming, but also low in batch production efficiency, and the performance of the obtained graphite bipolar plate is not high (such as bending strength). SUMMARY

[0007] The present application aims to provide a batch preparation method of a PEMFC flexible graphite bipolar plate, so as to solve the technical problems in the prior art that the impregnation process of the graphite bipolar plate is not only time-consuming, but also low in batch production efficiency, and the performance of the obtained graphite bipolar plate is not high.

[0008] To solve the above technical problems, the present application specifically provides the following technical scheme:

[0009] A batch preparation method of a PEMFC flexible graphite bipolar plate, comprising the following steps:

[0010] Step 100, placing the graphite bipolar plate to be impregnated in an impregnation tank;

[0011] Step 200, storing a preset amount of resin solution in a storage tank, connecting the storage tank and the impregnation tank through an impregnation pipeline and a backflow pipeline respectively, the impregnation pipeline being used to form a passage for the resin solution from the storage tank to the impregnation tank, and the backflow pipeline being used to form a passage for the resin solution from the impregnation tank to the storage tank;

[0012] Step 300, performing vacuumizing treatment on the impregnation tank by using a vacuum pump;

[0013] Step 400, opening the impregnation pipeline and closing the backflow pipeline, and the resin solution in the storage tank enters the impregnation tank under the action of negative pressure in the impregnation tank, and then the impregnation pipeline is closed;

[0014] Step 500, then pumping gas into the impregnation tank to make the pressure in the impregnation tank reach a first pressure preset value, so as to perform resin impregnation of the graphite bipolar plate;

[0015] Step 600, after the resin impregnation of the graphite bipolar plate is completed, opening the backflow pipeline, and the resin solution flows back to the storage tank under the action of the gas pressure in the impregnation tank;

[0016] Step 700, taking out the graphite bipolar plate product after the impregnation is completed.

[0017] As a preferred scheme of the present application, after each impregnation process is completed, the resin solution is supplemented into the storage tank when the resin solution flows back to the storage tank.

[0018] As a preferred scheme of the present application, when the gas pressure in the impregnation tank cannot meet the requirement that the resin solution completely flows back to the storage tank, part of the gas in the storage tank is extracted or the storage tank is vacuumized by using the vacuum pump before the backflow pipeline is opened.

[0019] As a preferred scheme of the present application, a pressure relief valve is connected to the storage tank, the pressure in the storage tank is monitored by using a pressure sensor, and when the pressure value in the storage tank exceeds a second pressure preset value, the pressure relief valve is automatically opened by using a control system to relieve pressure until the pressure value in the storage tank is lower than the second pressure preset value.

[0020] As a preferred scheme of the present application, a pressure relief valve is connected to the impregnation tank, the pressure in the impregnation tank is monitored by using a pressure sensor, and when the pressure value in the impregnation tank exceeds a second pressure preset value, the pressure relief valve is automatically opened by using a control system to relieve pressure until the pressure value in the impregnation tank is lower than the second pressure preset value.

[0021] As a preferred scheme of the present application, the second pressure preset value is 1.5 MPa.

[0022] As a preferred scheme of the present application, the first pressure preset value is 0.8-1.5 MPa;

[0023] The gas is pumped into the impregnation tank by the air compressor and is pressurized by the gas pressurizing device, so that the gas pumped into the impregnation tank reaches the first pressure preset value.

[0024] As a preferred scheme of the present application, the gas pressurizing device is used to pressurize the gas to 1.3 Mpa before sending it into the impregnation tank.

[0025] As a preferred scheme of the present application, a filtering device is arranged on the reflux pipeline to filter the graphite carbon powder particles contained in the resin solution during the reflux of the resin solution from the impregnation tank to the liquid storage tank.

[0026] As a preferred scheme of the present application, the specific method for filtering the graphite carbon powder particles contained in the resin solution by the filtering device arranged on the reflux pipeline includes:

[0027] Step 1, the filtering device includes a first filtering channel and a second filtering channel constructed on the reflux pipeline, the first filtering channel and the second filtering channel can be switched in position, and a filtering body is arranged in each of the first filtering channel and the second filtering channel.

[0028] The filtering body of the first filtering channel or the second filtering channel has its liquid inlet always facing the impregnation tank when it is connected to the reflux pipeline.

[0029] Step 2, when the first filtering pipeline is connected to the reflux pipeline as a part of the reflux pipeline, the resin solution flowing from the impregnation tank to the liquid storage tank is filtered by the filtering body.

[0030] The second filtering channel is connected to the cleaning pipeline, the cleaning liquid is injected into the pipeline through the liquid supply end at one end of the cleaning pipeline, the filtering body in the second filtering channel is flushed, and the flushed solution is collected by the collection end connected to the other end of the cleaning pipeline.

[0031] Step 3, after the first filtering pipeline works for a period of time, the positions of the first filtering channel and the second filtering channel are switched, so that the second filtering channel is connected to the reflux pipeline and the first filtering channel is connected to the cleaning pipeline.

[0032] The direction of the cleaning liquid provided by the liquid supply end through the first filtering channel or the second filtering channel is opposite to the direction of the resin solution flowing in the first filtering channel or the second filtering channel.

[0033] Compared with the prior art, the present application has the following beneficial effects:

[0034] The application improves the impregnation pressure of the graphite polar plate by increasing the pressure in the impregnation tank, and controls the negative pressure state in the impregnation tank and the resin storage tank by the vacuum pump, so that the resin flows between the two tank bodies, reduces the resin impregnation time of the flexible graphite bipolar plate, realizes the efficient resin impregnation of the PEMFC flexible graphite bipolar plate, and improves the bending strength of the graphite bipolar plate. BRIEF DESCRIPTION OF DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the following embodiment or prior art description will be briefly introduced. Obviously, the drawings in the following description are only exemplary, and other drawings can be obtained by the provided drawings without creative labor for those skilled in the art.

[0036] Figure 1 It is a schematic diagram of the overall structure of the embodiment of the present application.

[0037] Figure 2 It is a schematic diagram of the method flow of the embodiment of the present application.

[0038] Figure 3 It is a schematic diagram of the return pipe structure of the embodiment of the present application.

[0039] Figure 4 It is a schematic diagram of the filter device structure of the embodiment of the present application.

[0040] The numbers in the drawings represent the following:

[0041] 1-impregnation tank; 2-resin storage tank; 3-vacuum pump; 4-air compressor; 5-first pipeline; 6-second pipeline; 7-third pipeline; 8-three-way valve; 9-filter device; 10-gas pressure boosting device; 11-pressure relief valve; 12-safety valve; 13-first valve; 14-second valve; 15-third valve; 16-valve chamber; 17-valve port; 18-valve body; 19-first filter passage; 20-second filter passage; 191-pipeline main body; 192-filter pipe; 193-liquid inlet; 21-valve seat. DETAILED DESCRIPTION

[0042] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0043] As Figure 1 and Figure 2As shown, the embodiment provides a batch preparation method of PEMFC flexible graphite bipolar plate, which comprises the following steps:

[0044] Step 100, placing the graphite bipolar plate to be impregnated into the impregnation tank;

[0045] Step 200, storing a preset amount of resin solution in the liquid storage tank, and connecting the liquid storage tank and the impregnation tank through the impregnation pipeline and the backflow pipeline respectively, wherein the impregnation pipeline is used to form a passage for the resin solution from the liquid storage tank to the impregnation tank, and the backflow pipeline is used to form a passage for the resin solution from the impregnation tank to the liquid storage tank;

[0046] Step 300, vacuumizing the impregnation tank by using the vacuum pump;

[0047] Step 400, opening the impregnation pipeline and closing the backflow pipeline, and the resin solution in the liquid storage tank enters the impregnation tank under the action of negative pressure in the impregnation tank, and then the impregnation pipeline is closed;

[0048] Step 500, then pumping gas into the impregnation tank to make the pressure in the impregnation tank reach a first pressure preset value, so as to perform the resin impregnation process of the graphite bipolar plate;

[0049] Step 600, after completing the resin impregnation of the graphite bipolar plate, opening the backflow pipeline, and the resin solution flows back to the liquid storage tank under the action of gas pressure in the impregnation tank;

[0050] Step 700, taking out the graphite bipolar plate product after impregnation.

[0051] The method provided by the embodiment mainly completes the resin impregnation of the graphite bipolar plate in the impregnation tank under a certain pressure by pumping gas into the impregnation tank, which can greatly reduce the time for completing the impregnation of the graphite bipolar plate, and also improves the bending strength of the graphite bipolar plate product.

[0052] In addition, the whole preparation method is more conducive to batch preparation of the graphite bipolar plate, and can improve the batch preparation effect as follows:

[0053] Firstly, the vacuum negative pressure of the impregnation tank and the negative pressure difference with the liquid storage tank are used to realize the supply of the resin in the liquid storage tank to the impregnation tank.

[0054] Secondly, the pressure difference between the impregnation tank and the liquid storage tank can also make the unused resin solution in the impregnation tank flow back to the liquid storage tank.

[0055] The resin solution supply mode does not need to increase the pump for conveying the resin solution, which is beneficial to reduce the structure of the whole system and reduce the cost. The pressure transformation between the infiltration tank and the liquid storage tank is constructed, which avoids the problem that the system cannot work due to the failure of the conveying pump, and is more beneficial to the stability of the infiltration tank and the liquid storage tank system based on the method.

[0056] Moreover, the resin solution is conveyed between the infiltration tank and the liquid storage tank by using the existing negative pressure condition generated by the vacuum requirement and the gas pressure infiltration, instead of adding vacuum equipment and gas pumping equipment.

[0057] Furthermore, the method provided by the embodiment can supplement the resin solution into the liquid storage tank when the resin solution flows back to the liquid storage tank after completing one or several infiltration processes.

[0058] Considering that the pressure in the infiltration tank is set according to the infiltration requirement, and the gas pressure in the infiltration tank cannot meet the requirement that the resin solution completely flows back to the liquid storage tank, the embodiment can further increase the vacuum pump, and part of the gas in the liquid storage tank is extracted or the liquid storage tank is extracted to the vacuum state by the vacuum pump before the backflow pipeline between the infiltration tank and the liquid storage tank is opened.

[0059] Considering that the pressure in the liquid storage tank and the infiltration tank may exceed the maximum pressure value or the target pressure value, and affect the preparation of the graphite bipolar plate, the embodiment further provides the following embodiments:

[0060] A pressure relief valve is connected to the liquid storage tank, the pressure in the liquid storage tank is monitored by a pressure sensor, and when the pressure value in the liquid storage tank exceeds the second pressure preset value, the pressure relief valve is automatically opened by the control system to relieve the pressure in the liquid storage tank to be lower than the second pressure preset value.

[0061] A pressure relief valve is connected to the infiltration tank, the pressure in the infiltration tank is monitored by a pressure sensor, and when the pressure value in the infiltration tank exceeds the second pressure preset value, the pressure relief valve is automatically opened by the control system to relieve the pressure in the infiltration tank to be lower than the second pressure preset value.

[0062] According to experiments, the second pressure preset value is 1.5 MPa.

[0063] A gas booster device is arranged in the pipeline for supplying gas to the infiltration tank from the air compressor, the gas booster device is used to pressurize the gas to 0.8-1.5 MPa and then send the gas into the infiltration tank, so that the gas pumped into the infiltration tank reaches the first pressure preset value, and the first pressure preset value range adjusted according to the real-time requirement of the graphite bipolar plate in the infiltration tank is 0.8-1.5 MPa.

[0064] The following further illustrates the present embodiment in combination with experiments of the flexible graphite bipolar plate impregnation process.

[0065] The same batch of the same flexible graphite bipolar plate sample was used to perform the impregnation process according to the same method above, and different impregnation pressures were used to obtain the following examples:

[0066] (Example 1)

[0067] The impregnation pressure was 0.8 MPa, the impregnation time was 240 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 56 MPa.

[0068] (Example 2)

[0069] The impregnation pressure was 1.0 MPa, the impregnation time was 120 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 62 MPa.

[0070] (Example 3)

[0071] The impregnation pressure was 1.2 MPa, the impregnation time was 50 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 67 MPa.

[0072] (Example 4)

[0073] The impregnation pressure was 1.3 MPa, the impregnation time was 30 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 68 MPa.

[0074] (Example 5)

[0075] The impregnation pressure was 1.4 MPa, the impregnation time was 30 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 67.9 MPa.

[0076] (Example 6)

[0077] The impregnation pressure was 1.5 MPa, the impregnation time was 30 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 68 MPa.

[0078] (Comparative Example)

[0079] The impregnation pressure was 0.7 MPa, the impregnation time was 360 min, and the final obtained flexible graphite bipolar plate product had a bending strength of 48 MPa.

[0080] Among them, the comparative example is the impregnation pressure and impregnation time used in the existing graphite bipolar plate impregnation process.

[0081] The above examples are arranged into a table as follows:

[0082] Serial number Infiltration pressure (MPa) Infiltration time (min) Bending strength of bipolar plate (MPa) Example 1 0.8 240 56 Example 2 1.0 120 62 Example 3 1.2 60 67 Example 4 1.3 30 68 Example 5 1.4 30 67.9 Example 6 1.5 30 68 Comparative example 0.7 360 48

[0083] From the above table, it can be clearly seen that in the present embodiment, the resin impregnation of the graphite bipolar plate in the impregnation tank is realized by pressurization. Under the conventional impregnation pressure, by continuously increasing the pressure, the graphite bipolar plate is impregnated with resin after the gas pressurization device is used to pressurize the gas to 1.3 MPa, that is, the pressure in the impregnation tank is maintained at 1.3 MPa, and the time for the graphite bipolar plate to complete the resin impregnation is controlled within 30 minutes, and the bending strength reaches the maximum. Continue to increase the impregnation pressure, the bending strength of the graphite bipolar plate changes little.

[0084] Therefore, in the present embodiment, the gas pressure and the performance of the overall system are considered. That is, the higher the pressure in the impregnation tank, the higher the structural performance requirement, the greater the sealing requirement of the pipeline, and the system needs to meet the resin backflow action between the impregnation tank and the liquid storage tank. Preferably, the pressure in the impregnation tank is 1.3 MPa.

[0085] A filtering device is arranged on the backflow pipeline to filter the graphite particles contained in the resin solution during the backflow of the resin solution from the impregnation tank to the liquid storage tank.

[0086] Since both the mold impregnation and the gas pressurization impregnation have the problem of carbon powder particles, the flexible graphite plate needs to be punched and sheared during the mold forming of the raw material plate, which may have burrs. The burr carbon powder particles may fall off during the resin transmission movement of the mold formed graphite plate. The carbon powder particles may be more in batch production, which may block the resin transmission channel and affect the efficiency of the fluid passing through the channel.

[0087] The most important effect is that the carbon powder particles are easily adsorbed on the surface of the flexible graphite plate in the resin, which hinders the resin from entering the pores of the flexible graphite plate, thereby affecting the impregnation effect of the product and reducing the mechanical properties of the final product of the flexible graphite plate.

[0088] Currently, the resin is extracted from the impregnation tank body for sedimentation and then cleaned. Therefore, the existing state treatment of the resin solution in the impregnation tank is performed after a certain number of impregnation operations of the graphite bipolar plate in the impregnation tank, and the resin impregnation effect of the graphite bipolar plate is reduced each time.

[0089] Therefore, in the present embodiment, two channels are arranged between the impregnation tank and the liquid storage tank, including an impregnation pipeline and a backflow pipeline. A filtering device, which can be a filter screen, is arranged on the backflow pipeline to filter the graphite carbon powder particles existing in the resin during the backflow of the resin to the liquid storage tank.

[0090] And this is exactly the main reason why the pump body is not used as the power source for resin delivery in the above-mentioned embodiments. Graphite carbon powder particles will accumulate in the pump body, affecting the delivery effect of the pump body, or the graphite carbon powder particles will remain in the pump body. After several infiltration operations, the residual graphite carbon powder particles in the pump body will still be pumped into the infiltration tank by the pump body, thereby affecting the infiltration effect of the graphite bipolar plate.

[0091] In the present embodiment, a filter screen is arranged on the return pipeline to filter the resin and block the graphite carbon powder particles in the return pipeline. When the return pipeline is closed, it will not affect the resin solution in the infiltration tank. At the same time, the resin solution is not extracted and precipitated. Extracting the resin solution will stop the work of the infiltration tank.

[0092] In the present embodiment, the filtration device of the return pipeline only needs to be disassembled and cleaned during the interval of the resin infiltration work of the infiltration tank, so it does not affect the batch production of the graphite bipolar plate at all.

[0093] The graphite bipolar plate is first placed in the tool basket, and then the tool basket is placed in the infiltration tank body.

[0094] As shown in Figure 1 The present embodiment provides an infiltration device for batch production of PEMFC flexible graphite bipolar plates, which is used to realize the infiltration method for batch production of PEMFC flexible graphite bipolar plates.

[0095] Specifically, it includes:

[0096] The infiltration tank 1 is used to place the graphite bipolar plate.

[0097] The liquid storage tank 2 stores a predetermined amount of resin solution. The liquid storage tank 2 is respectively connected to the infiltration tank 1 through the infiltration pipeline 5 and the return pipeline 6. The infiltration pipeline 5 is used to form a passage for the resin solution from the liquid storage tank 2 to the infiltration tank 1. The return pipeline 6 is used to form a passage for the resin solution from the infiltration tank 1 to the liquid storage tank 2.

[0098] In the specific work of the device, the vacuum pump 3 is connected to the liquid storage tank 2 and the infiltration tank 1. The vacuum pump 3 is used to vacuum the infiltration tank 1 after placing the graphite bipolar plate in the infiltration tank 1, so that there is a pressure difference between the infiltration tank 1 and the liquid storage tank 2.

[0099] Then, the infiltration pipeline 5 is opened, and the return pipeline 6 is closed. The resin solution in the liquid storage tank 2 enters the infiltration tank 1 under the negative pressure in the infiltration tank 1, and then the infiltration pipeline 5 is closed.

[0100] The air compressor 4 is connected to the infiltration tank 1 through the pipeline 7. The air compressor 4 pumps gas into the infiltration tank 1 to make the pressure in the infiltration tank 1 reach a predetermined value, so as to perform the resin infiltration process of the graphite bipolar plate.

[0101] In the embodiment of the device, the graphite polar plate in the impregnation tank 1 completes resin impregnation under a certain pressure mainly by the way of the air compressor 4 pumping gas into the impregnation tank 11, which can greatly reduce the time for the graphite bipolar plate to complete impregnation, and also improve the bending strength of the graphite bipolar plate product.

[0102] In the embodiment of the device, compressed air is used as the pressurized working medium, which has a low cost and can avoid the problem of complex overall system structure caused by the need to provide and connect other working medium supply equipment.

[0103] In the above-mentioned resin supply mode, it is generally not necessary to provide power for resin solution delivery by increasing the pump body for delivering the resin solution, which is conducive to reducing the structure of the entire system and reducing costs, and by constructing the pressure conversion between the impregnation tank 1 and the liquid storage tank 2, the problem of system failure caused by failure of the delivery pump body is avoided, which is more conducive to the stability of the impregnation tank 1 and the liquid storage tank 2 system based on this method.

[0104] In the device, the vacuum pump 3 is connected to the liquid storage tank 2 and the impregnation tank 1 through the total and partial pipelines, thereby completing the positive and negative pressure control between the liquid storage tank 2 and the impregnation tank 1.

[0105] Of course, the air compressor 4 can be used to apply positive pressure to the impregnation tank 1, and when the resin impregnation of the graphite polar plate is completed, the backflow pipeline 6 is opened, and the resin in the impregnation tank 1 will flow into the liquid storage tank 2 under the action of positive pressure, completing the one-way delivery of the resin solution between the impregnation tank 1 and the liquid storage tank 2.

[0106] Further, in the case that the impregnation pipeline 5 is closed and the liquid storage tank 2 maintains normal pressure, the resin in the impregnation tank 1 can completely enter the liquid storage tank 2 under the condition that the air compressor delivers air, and then the valve of the backflow pipeline 6 is closed. When the graphite bipolar plate is placed in the impregnation tank 1 next time, the valve of the backflow pipeline 6 is opened first to connect the backflow pipeline 6 to the liquid storage tank 2, thereby increasing the pressure in the liquid storage tank 2, and then the valve of the backflow pipeline is closed, and then the valve of the impregnation pipeline 5 is opened to connect the impregnation pipeline 5, at this time the resin will enter the impregnation tank 1 (the impregnation tank 1 is released to negative pressure at this time) through the impregnation pipeline 5.

[0107] Through the above-mentioned mode, the resin can be transferred between the two tanks by the air compressor, the impregnation pipeline 5 and the backflow pipeline 6, that is, it can not rely on the addition of vacuum equipment and gas pumping equipment, but use the existing negative pressure condition generated by the original vacuum requirement and air pressure impregnation to complete the flow of the resin solution.

[0108] Obviously, the operation steps are too complex, and a large resin pumping pressure is required, and the structural performance requirements of the liquid storage tank 2 and the infiltration tank 1 are high. Therefore, in the embodiment, the infiltration tank 1 and the liquid storage tank 2 are connected by the same vacuum pump 3, and the negative pressure difference of the two is adjusted and converted.

[0109] Further, in the method provided by the embodiment, after each or several infiltration processes are completed, the resin solution is refluxed to the liquid storage tank 2, and the liquid storage tank 2 is supplemented with resin solution.

[0110] Considering that the pressure in the infiltration tank 1 is set according to the infiltration needs, and there is a case that the gas pressure in the infiltration tank 1 cannot meet the complete reflux of the resin solution to the liquid storage tank 2, the embodiment can further increase the vacuum pump 3, and before the reflux pipeline between the infiltration tank 1 and the liquid storage tank 2 is opened, the vacuum pump 3 extracts part of the gas in the liquid storage tank 2 or extracts it to a vacuum state.

[0111] Considering that the pressures in the liquid storage tank 2 and the infiltration tank 1 can exceed the maximum pressure value or the target pressure value, and affect the preparation of the graphite bipolar plate, the embodiment further provides the following embodiment:

[0112] The infiltration tank 1 and the liquid storage tank 2 are both provided with a pressure relief valve 11 and a safety valve 12. The safety valve 12 opens the pressure relief when the pressure of the infiltration tank 1 or the liquid storage tank 2 exceeds 1.5 MPa.

[0113] Further, in the embodiment, the two ends of the reflux pipeline 6 are connected to the two ends of the infiltration pipeline 5 respectively, and the end of the reflux pipeline 6 is connected to the infiltration pipeline 5 through the three-way valve 8. The reflux pipeline 6 is not directly connected to the tank body of the infiltration tank 1 and the liquid storage tank 2, which can avoid excessive damage to the structure of the tank body, and the requirement for the structural performance of the tank body is relatively small.

[0114] The filtration device 9 is arranged on the reflux pipeline 6; after the graphite bipolar plate in the infiltration tank 1 is infiltrated, the three-way valve 8 closes the infiltration pipeline 5, and the unused resin solution in the infiltration tank 1 is filtered through the filtration device 9 on the reflux pipeline 6 and then enters the liquid storage tank 2, so as to filter the graphite carbon powder particles contained in the infiltrated resin of the infiltration tank 1.

[0115] Of course, in consideration of the convenience of disassembling the reflux pipeline 6 and cleaning the filtration device 9, the reflux pipeline 6 and the infiltration pipeline 5 can also be connected through a quick release.

[0116] A gas booster 10 is arranged on the pipeline 7, and the gas booster 10 is used to adjust the pressure of the compressed air injected by the air compressor device into the infiltration tank 1 within a preset pressure range. The preset pressure adjustment range of the gas booster 10 is 0.8-1.5 MPa. The purpose is to provide a dynamically adjustable pressure range in the infiltration tank 1 for different performance gypsum bipolar plates, so that the pressure in the infiltration tank 1 can be increased to improve the infiltration efficiency, and at the same time, the pressure is not too high to cause the structure of the graphite bipolar plate to be damaged.

[0117] A first valve 13 is arranged on the pipeline 7 between the gas booster 10 and the infiltration tank 1, and a second valve 14 and a third valve 15 are arranged on the pipelines connecting the infiltration tank 1 and the resin storage tank 2 to the vacuum pump 3, respectively. By controlling the opening and closing of the second valve 14 and the third valve 15, the vacuum pump 3 causes the infiltration tank 1 and the resin storage tank 2 to have a pressure difference.

[0118] The embodiment relates to the technical field of proton exchange membrane fuel cells, in particular to an infiltration device for efficiently and batch-preparing a PEMFC flexible graphite bipolar plate, which increases the infiltration pressure by adding a gas booster on a gas pipeline (pipeline 7), thereby being capable of batch-preparing a high-performance PEMFC flexible graphite bipolar plate, reducing the infiltration time of the flexible graphite bipolar plate, and improving the batch production efficiency of the PEMFC flexible graphite bipolar plate.

[0119] Meanwhile, a filtering device 9 is arranged before the transmission channel of the infiltration tank and the resin storage tank, the resin flowing out of the infiltration tank 1 is caused to flow through different pipelines through the infiltration pipeline 5 and the backflow pipeline 6, and the filtering device 9 is arranged on the backflow pipeline 6, so that the graphite carbon powder particles in the resin can be filtered during the backflow of the resin into the storage tank, and the resin transported again into the infiltration tank 1 is kept clean and free of impurities, thereby not affecting the continuous work of the infiltration tank 1, and the graphite carbon powder particles do not need to be removed by the way of extracting the resin from the infiltration tank or the storage tank to deposit, and the efficient batch production of the PEMFC flexible graphite bipolar plate can be realized.

[0120] As shown in FIGS. Figure 3 and Figure 4 The specific method for arranging the filtering device on the backflow pipeline to filter the graphite carbon powder particles contained in the resin solution includes the following steps.

[0121] Step 1, the filtering device includes a first filtering channel and a second filtering channel capable of position switching constructed on the backflow pipeline, and a filtering main body is arranged in each of the first filtering channel and the second filtering channel, wherein the filtering main body of the first filtering channel or the second filtering channel is always directed towards the infiltration tank when connected to the backflow pipeline.

[0122] Step 2, when the first filter pipe is connected as a part of the backflow pipe, the resin solution flowing from the soaking tank to the storage tank is filtered by the filter body in the second filter channel;

[0123] The second filter channel is connected to the cleaning pipe, and the cleaning liquid is injected into the pipe through the liquid supply end at one end of the cleaning pipe to flush the filter body in the second filter channel, and the flushed solution is collected by the collection end connected to the other end of the cleaning pipe;

[0124] Step 3, after the first filter pipe works for a period of time, the positions of the first filter channel and the second filter channel are switched, so that the second filter channel is connected to the backflow pipe, and the first filter channel is connected to the cleaning pipe;

[0125] The direction of the cleaning liquid provided by the liquid supply end through the first filter channel or the second filter channel is opposite to the direction of the resin solution flowing in the first filter channel or the second filter channel.

[0126] Further, as shown in Figure 3 and Figure 4 The embodiment provides a backflow pipe and a filter device arranged in the backflow pipe, which comprises a valve seat 21, a valve cavity 16 is arranged in the valve seat 21, four valve ports 17 are arranged on the valve seat 21, and the four valve ports 17 are all connected to the valve cavity 16, wherein the valve cavity 16 can be a disc-shaped cavity or a spherical cavity structure, a valve body 18 arranged in the valve cavity 16 is matched with the structure of the valve cavity 16, so that the surface of the valve body 18 and the inner wall of the valve cavity 16 are in close contact.

[0127] Then, on the inlet and outlet of the valve cavity 16, the valve cavity 16 has four valve ports 17, the four valve ports 17 are grouped into two valve ports 17, one valve port 17 in the two valve ports 17 of one group is connected to the storage tank 2 through a pipe A, and the other valve port 17 is connected to the soaking tank 1 through a pipe B (that is, the backflow pipe 6 in the application is formed);

[0128] One valve port 17 in the two valve ports 17 of the other group is connected to the liquid supply end through a pipe C, specifically an external cleaning solution supply device, and the other valve port 17 is connected to the collection end, specifically a collection box or cylinder.

[0129] The valve cavity 16 is provided with the valve body 18, and the valve body 18 is provided with the first filter channel 19 and the second filter channel 20;

[0130] The first filter channel 19 is connected to the pipe A and the pipe B;

[0131] The second filter channel 20 is connected to the pipe C and the pipe D;

[0132] The valve body 18 is driven by the driving part to rotate and switch the positions of the first filter channel 19 and the second filter channel 20, so that the second filter channel 20 is connected with the pipe A and the pipe B, and the first filter channel 19 is connected with the pipe C and the pipe D.

[0133] The inlet end of the first filter channel 19 is connected with the valve port 17 of the pipe B, and the inlet end of the second filter channel 20 is directed to the valve port 17 of the pipe D.

[0134] In the embodiment, two filter channels are arranged on the valve body 18, the two filter channels have the same structure, the positions of the two filter channels are switched by rotating the valve body 18 in the valve cavity 16, so that the two filter channels are in two working modes of working and cleaning, and in the above-mentioned embodiment of the infiltration method, the filtration device can work without stopping, and the filtration net in the filtration device does not need to be disassembled and cleaned during stopping, and the infiltration and filtration efficiency of the graphite bipolar plate is greatly improved.

[0135] In the position design of the above-mentioned four valve ports 17, a plane rectangular coordinate system is constructed with the center of the valve body 18 as the origin, and then the four valve ports 17 are respectively located on the coordinate axes of the plane rectangular coordinate system to realize the central symmetric distribution, and a group of two valve ports 17 are arranged in central symmetry.

[0136] Of course, the distribution of the four valve ports 17 is preferably in the same plane, and in the embodiment, only the rotation of the valve body is needed to switch the connection of the first filter channel 19 and the second filter channel 20 with the cleaning pipes (the pipe C and the pipe D) and the return pipes (the pipe A and the pipe B).

[0137] Further, in the embodiment, if the four valve ports 17 are located on the same circumference of the valve cavity 16 (the valve cavity 16 is a spherical cavity), the first filter channel 19 is a cylindrical pipe passing through the diameter of the valve body 18, and the middle of the second filter channel 20 is curved to avoid the first filter channel 19, at this time, the valve body 18 only needs to be driven to rotate along the circumference to realize the switching of the pipes of the first filter channel 19 and the second filter channel 20.

[0138] If the first filter channel 19 and the second filter channel 20 are located on different circumferences of different valve bodies 18, the first filter channel 19 and the second filter channel 20 are both cylindrical structures, at this time, the driving direction of the driving part to drive the valve body 18 is the direction of the center line of the openings of the first filter channel 19 and the second filter channel 20 on the surface of the valve body 18.

[0139] In the embodiment, the direction of liquid flow in the cleaning pipeline (pipeline C and pipeline D) is opposite to the direction of flow in the return pipeline, which aims to clean and remove the carbon powder particles filtered in the first filter channel 19 or the second filter channel 20. Therefore, a specific embodiment of the first filter channel 19 (the structure of the first filter channel 19 and the second filter channel 20 is the same) is provided.

[0140] The first filter channel 19 includes a pipeline body 191, and the inside of the pipeline body 191 is provided with a plurality of filter tubes 192 distributed in a honeycomb shape. The surface of the filter tube 192 has filter pores that do not allow graphite carbon powder particles in a certain particle size range to pass through. The filter tube 192 is along the axial direction of the pipeline body 191, one end of the filter tube 192 is open to form a liquid inlet 193, and the other end of the filter tube 192 is closed. The liquid inlet 193 is consistent with the entering end of the pipeline body 191.

[0141] When the return pipeline 6 is in the working state, that is, the resin solution enters the valve cavity 16 through the pipeline B into the first filter channel 19, the resin solution enters the filter tube 192 from the liquid inlet 193, and the graphite carbon powder particles contained in the resin solution are intercepted by the filter tube 192. At the same time, the graphite carbon powder particles are continuously accumulated at the bottom of the filter tube 192, and most of the resin solution will be filtered out from the side wall of the filter tube 192 to flow out to the other end of the pipeline body 191 relative to the liquid inlet 193, and then enter the pipeline A.

[0142] When the filter tube 192 specifically implements the filtering function, the bottom wall of the filter tube 192 filters the graphite carbon powder particles, and the resin solution entering the filter tube 192 is along the axial direction of the filter tube 192. Therefore, even if there are graphite carbon powder particles on the side wall of the filter tube 192, the graphite carbon powder particles will be pushed to the bottom of the filter tube 192 (the closed end of the filter tube 192 opposite to the liquid inlet 193) due to the flow of the resin solution. The filtering mode of the filter tube 192 will not greatly affect the filtering rate of the resin solution through the filter tube 192 as the working time increases.

[0143] Obviously, when the first filter pipeline 19 is switched to the cleaning pipeline, the cleaning solution will impact the filtered graphite carbon powder particles from the bottom of the filter tube 192 (relative to the closed end), so that the graphite carbon powder particles are discharged from the liquid inlet 193 of the filter tube 192 into the pipeline D, and then collected by the collection end.

[0144] The filter tube 192 provided in the embodiment can be a hollow tubular filter core with a fixed shape. The main constituent material of the filter core is any one or a combination of polytetrafluoroethylene, nylon, and polyether sulfone.

[0145] The above examples are only exemplary embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Those skilled in the art can make various modifications or equivalent replacements to the present application within the spirit and protection scope of the present application, and such modifications or equivalent replacements are also considered to fall within the protection scope of the present application.

Claims

1. A method for batch production of PEMFC flexible graphite bipolar plates by impregnation, characterized in that, It comprises the following steps: Step 100, put the graphite bipolar plate to be impregnated into the impregnation tank; Step 200, store a predetermined amount of resin solution in the liquid storage tank, and respectively connect the liquid storage tank and the impregnation tank through the impregnation pipeline and the backflow pipeline, the impregnation pipeline is used to form the passage of the resin solution from the liquid storage tank to the impregnation tank, and the backflow pipeline is used to form the passage of the resin solution from the impregnation tank to the liquid storage tank; Step 300, vacuumize the impregnation tank with a vacuum pump; Step 400, open the impregnation pipeline and close the backflow pipeline, and the resin solution in the liquid storage tank enters the impregnation tank under the negative pressure in the impregnation tank, and then the impregnation pipeline is closed; Step 500, then pump gas into the impregnation tank to make the pressure in the impregnation tank reach a first pressure preset value, and the first pressure preset value is 0.8-1.5 MPa, so as to perform the resin impregnation process of the graphite bipolar plate; Step 600, after the resin impregnation of the graphite bipolar plate is completed, the backflow pipeline is opened, and the resin solution flows back to the liquid storage tank under the action of the gas pressure in the impregnation tank; Step 700, take out the finished graphite bipolar plate product; The gas is pumped into the impregnation tank by an air compressor and is pressurized by a gas pressurizing device to make the gas pumped into the impregnation tank reach the first pressure preset value; The gas pressurizing device is used to pressurize the gas to 1.3 MPa and then send it into the impregnation tank; A filtering device is arranged on the backflow pipeline to filter the graphite carbon powder particles contained in the resin solution during the backflow of the resin solution from the impregnation tank to the liquid storage tank; The specific method for filtering the graphite carbon powder particles contained in the resin solution by the filtering device arranged on the backflow pipeline comprises: Step 1, the filtering device comprises a first filtering channel and a second filtering channel constructed on the backflow pipeline, the first filtering channel and the second filtering channel can be switched in position, and a filtering body is arranged in each of the first filtering channel and the second filtering channel; The filtering body of the first filtering channel or the second filtering channel always faces the impregnation tank when it is connected to the backflow pipeline; Step 2, when the first filtering pipeline is connected to the backflow pipeline as a part of the backflow pipeline, the resin solution flowing from the impregnation tank to the liquid storage tank is filtered by the filtering body; The second filtering channel is connected to the cleaning pipeline, cleaning liquid is injected into the pipeline through the liquid supply end at one end of the cleaning pipeline, the filtering body in the second filtering channel is flushed, and the flushed solution is collected by the collection end connected to the other end of the cleaning pipeline; Step 3, after the first filtering pipeline works for a period of time, the positions of the first filtering channel and the second filtering channel are switched, so that the second filtering channel is connected to the backflow pipeline and the first filtering channel is connected to the cleaning pipeline; The direction of the cleaning liquid provided by the liquid supply end through the first filtering channel or the second filtering channel is opposite to the direction of the resin solution flowing in the first filtering channel or the second filtering channel.

2. The impregnation method according to claim 1, wherein After each impregnation process is completed, the resin solution is returned to the storage tank, and the storage tank is replenished with resin solution.

3. The batch production method of claim 2, wherein the impregnation tank is connected to the storage tank through a return line, and the return line is provided with a valve. When the air pressure in the impregnation tank cannot meet the requirement of returning the resin solution to the storage tank, the storage tank is partially evacuated or vacuumized by a vacuum pump before the valve of the return line is opened.

4. The batch production method of claim 1, wherein the storage tank is connected to a pressure relief valve, and the pressure in the storage tank is monitored by a pressure sensor. When the pressure in the storage tank exceeds the second pressure preset value, the pressure relief valve is automatically opened by a control system to release pressure until the pressure in the storage tank is lower than the second pressure preset value.

5. The batch production method of claim 1, wherein the impregnation tank is connected to a pressure relief valve, and the pressure in the impregnation tank is monitored by a pressure sensor. When the pressure in the impregnation tank exceeds the second pressure preset value, the pressure relief valve is automatically opened by a control system to release pressure until the pressure in the impregnation tank is lower than the second pressure preset value.

6. The batch production method of claim 5, wherein the second pressure preset value is 1.5 MPa. ​

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