A method of impregnating a fuel cell flexible graphite bipolar plate

Abstract

The present application relates to the technical field of fuel cell, especially to a kind of impregnation method of fuel cell flexible graphite polar plate.The present application first carries out pre-treatment to the flexible graphite polar plate after forming, obtains pre-treatment polar plate;Then it is immersed in cold isostatic pressing working tank body filled with incompressible fluid, the cold isostatic pressing working tank body is closed, and is pressurized after pressurization;Pressure holding ends after pressure relief to normal pressure, the cold isostatic pressing working tank body is opened, and the flexible graphite polar plate after cold isostatic pressing impregnation is taken out, and impregnation is completed after post-processing.The present application realizes the high-speed impregnation of polar plate by cold isostatic pressing impregnation process, and greatly improves production efficiency.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to an impregnation method for flexible graphite plates in fuel cells. Background Technology

[0002] Flexible graphite bipolar plates have become an important development direction in the field of bipolar plates due to their excellent corrosion resistance, formability, low price, and ability to be mass-produced and continuously manufactured. Traditional processes typically involve molding, impregnation, cleaning, curing, and bonding to prepare bipolar plates. However, the use of compressed air for pressurization in traditional processes makes the impregnation process too time-consuming, resulting in low plate preparation efficiency. Facing the rapidly growing fuel cell industry, traditional processes can only meet market demand through large amounts of equipment, space, and manpower. How to significantly improve impregnation efficiency to match downstream demand is a major challenge in the impregnation process of flexible graphite bipolar plates. Summary of the Invention

[0003] To address the shortcomings of existing technologies with excessively long impregnation times and significantly shorten the impregnation period, this invention aims to provide an impregnation method for flexible graphite electrode plates in fuel cells. This invention first pre-treats the formed flexible graphite electrode plates to obtain pre-treated electrode plates. Then, it immerses these pre-treated electrode plates in a cold isostatic pressing (COP) tank filled with incompressible fluid. The COP tank is then sealed and pressurized and held. After pressurization, the pressure is released to atmospheric pressure, the COP tank is opened, and the cold isostatically impregnated flexible graphite electrode plates are removed. Post-processing completes the impregnation process. This invention achieves high-speed impregnation of electrode plates through the cold isostatic pressing (COP) impregnation process, significantly improving production efficiency.

[0004] The objective of this invention can be achieved through the following technical solutions:

[0005] This invention provides a method for impregnating flexible graphite electrode plates for fuel cells, comprising the following steps:

[0006] (1) Immerse the pretreated electrode plate into a cold isostatic pressure working tank filled with incompressible fluid;

[0007] (2) Seal the cold isostatic pressing working tank and pressurize it;

[0008] (3) After pressurization is completed, maintain the pressure.

[0009] (4) After the pressure holding is completed, release the pressure to normal pressure and open the cold isostatic pressure working tank;

[0010] (5) Take out the flexible graphite electrode plate after cold isostatic pressing and impregnation, and complete the impregnation after post-processing.

[0011] In one embodiment of the present invention, in step (1), the pretreated electrode plate is prepared by the following method:

[0012] The formed flexible graphite electrode plate is pretreated to obtain a pretreated electrode plate.

[0013] In one embodiment of the present invention, the pretreatment is exhaust treatment.

[0014] In one embodiment of the present invention, in step (1), the incompressible fluid is selected from one or more of liquid thermosetting resin, hydraulic oil or water.

[0015] In one embodiment of the present invention, the thermosetting resin is selected from one or more of acrylic resins, unsaturated resins, vinyl resins or epoxy resins.

[0016] In one embodiment of the present invention, in step (2), the pressurization rate is 0.5-5 MPa / s during the pressurization process.

[0017] In one embodiment of the present invention, in step (2), the pressure inside the cold isostatic working tank is increased to 10-600 MPa.

[0018] In one embodiment of the present invention, in step (3), the pressure holding time is 0.5-60 min.

[0019] In one embodiment of the present invention, in step (4), the depressurization rate is 1-5 MPa / s during the depressurization process.

[0020] In one embodiment of the present invention, in step (5), the post-processing is a cleaning and curing operation.

[0021] In one embodiment of the present invention, if the working tank is filled with the liquid resin to be impregnated, the electrode plate can be directly placed into the working tank of the equipment; if the working tank is filled with an incompressible fluid other than the liquid resin to be impregnated, the electrode plate needs to be placed in polyurethane or other soft mold that does not react with incompressible fluid.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] (1) Existing technologies typically use compressed air for pressurization, which makes the impregnation process too time-consuming and results in low electrode plate preparation efficiency. Compared with existing technologies, the impregnation method of a flexible graphite electrode plate for fuel cells of the present invention uses this process to impregnate the flexible graphite electrode plate, which can significantly shorten the process time and significantly improve production efficiency.

[0024] (2) The impregnation method of the flexible graphite electrode plate of the fuel cell of the present invention can significantly improve the yield of the flexible graphite electrode plate. Detailed Implementation

[0025] This invention provides a method for impregnating flexible graphite electrode plates for fuel cells, comprising the following steps:

[0026] (1) Immerse the pretreated electrode plate into a cold isostatic pressure working tank filled with incompressible fluid;

[0027] (2) Seal the cold isostatic pressing working tank and pressurize it;

[0028] (3) After pressurization is completed, maintain the pressure.

[0029] (4) After the pressure holding is completed, release the pressure to normal pressure and open the cold isostatic pressure working tank;

[0030] (5) Take out the flexible graphite electrode plate after cold isostatic pressing and impregnation, and complete the impregnation after post-processing.

[0031] In one embodiment of the present invention, in step (1), the pretreated electrode plate is prepared by the following method:

[0032] The formed flexible graphite electrode plate is pretreated to obtain a pretreated electrode plate.

[0033] In one embodiment of the present invention, the pretreatment is exhaust treatment.

[0034] In one embodiment of the present invention, in step (1), the incompressible fluid is selected from one or more of liquid thermosetting resin, hydraulic oil or water.

[0035] In one embodiment of the present invention, the thermosetting resin is selected from one or more of acrylic resins, unsaturated resins, vinyl resins or epoxy resins.

[0036] In one embodiment of the present invention, in step (2), the pressurization rate is 0.5-5 MPa / s during the pressurization process.

[0037] In one embodiment of the present invention, in step (2), the pressure inside the cold isostatic working tank is increased to 10-600 MPa.

[0038] In one embodiment of the present invention, in step (3), the pressure holding time is 0.5-60 min.

[0039] In one embodiment of the present invention, in step (4), the depressurization rate is 1-5 MPa / s during the depressurization process.

[0040] In one embodiment of the present invention, in step (5), the post-processing is a cleaning and curing operation.

[0041] In one embodiment of the present invention, if the working tank is filled with the liquid resin to be impregnated, the electrode plate can be directly placed into the working tank of the equipment; if the working tank is filled with an incompressible fluid other than the liquid resin to be impregnated, the electrode plate needs to be placed in polyurethane or other soft mold that does not react with incompressible fluid.

[0042] The present invention will now be described in detail with reference to specific embodiments.

[0043] Unless otherwise specified, all reagents used in the following embodiments are commercially available reagents, and all detection methods and means described herein are conventional detection methods and means in the art.

[0044] Example 1

[0045] This embodiment provides a method for impregnating flexible graphite electrode plates for fuel cells, including the following steps:

[0046] (1) The formed flexible graphite electrode plate is placed into an impregnation basket and degassing is performed to obtain a pretreated electrode plate;

[0047] (2) Immerse the pretreated electrode plate obtained in step (1) into a cold isostatic pressing working tank filled with acrylic resin liquid to be impregnated.

[0048] (3) Seal the cold isostatic pressure working tank and pressurize it to 35MPa at a rate of 0.5MPa / s;

[0049] (4) Hold the pressure for 5 minutes after pressurization is complete;

[0050] (5) After the pressure holding is completed, release the pressure to atmospheric pressure at a rate of 1MPa / s and open the cold isostatic pressure working tank;

[0051] (6) Take out the flexible graphite plate after cold isostatic pressing and impregnation, clean and solidify it to complete the impregnation and make a monopolar plate.

[0052] Example 2

[0053] This embodiment provides a method for impregnating flexible graphite electrode plates for fuel cells, including the following steps:

[0054] (1) The formed flexible graphite electrode plate is placed into an impregnation basket and degassing is performed to obtain a pretreated electrode plate;

[0055] (2) Immerse the pretreated electrode plate obtained in step (1) into a cold isostatic pressing working tank filled with unsaturated resin liquid to be impregnated;

[0056] (3) Seal the cold isostatic pressure working tank and pressurize it to 50MPa at a rate of 2MPa / s;

[0057] (4) After pressurization, maintain the pressure for 10 minutes;

[0058] (5) After the pressure holding is completed, release the pressure to atmospheric pressure at a rate of 5MPa / s and open the cold isostatic pressure working tank;

[0059] (6) Take out the flexible graphite plate after cold isostatic pressing and impregnation, clean and solidify it to complete the impregnation and make a monopolar plate.

[0060] Example 3

[0061] This embodiment provides a method for impregnating flexible graphite electrode plates for fuel cells, including the following steps:

[0062] (1) The formed flexible graphite electrode plate is placed into an impregnation basket and degassing is performed to obtain a pretreated electrode plate;

[0063] (2) Immerse the pretreated electrode plate obtained in step (1) into a cold isostatic pressing working tank filled with unsaturated resin liquid to be impregnated;

[0064] (3) Seal the cold isostatic pressure working tank and pressurize it to 10MPa at a rate of 0.5MPa / s;

[0065] (4) After pressurization, maintain the pressure for 60 minutes;

[0066] (5) After the pressure holding is completed, release the pressure to atmospheric pressure at a rate of 1MPa / s and open the cold isostatic pressure working tank;

[0067] (6) Take out the flexible graphite plate after cold isostatic pressing and impregnation, clean and solidify it to complete the impregnation and make a monopolar plate.

[0068] Example 4

[0069] This embodiment provides a method for impregnating flexible graphite electrode plates for fuel cells, including the following steps:

[0070] (1) The formed flexible graphite electrode plate is placed into an impregnation basket and degassing is performed to obtain a pretreated electrode plate;

[0071] (2) Immerse the pretreated electrode plate obtained in step (1) into a cold isostatic pressing working tank filled with unsaturated resin liquid to be impregnated;

[0072] (3) Seal the cold isostatic pressure working tank and pressurize it to 600MPa at a rate of 5MPa / s;

[0073] (4) Hold the pressure for 0.5 minutes after pressurization is complete;

[0074] (5) After the pressure holding is completed, release the pressure to atmospheric pressure at a rate of 5MPa / s and open the cold isostatic pressure working tank;

[0075] (6) Take out the flexible graphite plate after cold isostatic pressing and impregnation, clean and solidify it to complete the impregnation and make a monopolar plate.

[0076] It is worth noting that if the working tank is filled with an incompressible fluid other than the liquid resin to be impregnated, the electrode plate must be placed in a polyurethane or other soft mold that does not react with the incompressible fluid, and the other steps are the same.

[0077] 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 method of impregnating a flexible graphite pole plate for a fuel cell, characterized by, Includes the following steps: (1) Immerse the pretreated electrode plate into a cold isostatic pressure working tank filled with incompressible fluid; (2) Seal the cold isostatic pressure working tank and pressurize it; (3) After pressurization, maintain the pressure. (4) After the pressure holding is completed, release the pressure to atmospheric pressure and open the cold isostatic pressure working tank; (5) Take out the flexible graphite electrode plate after cold isostatic pressing and impregnation, and complete the impregnation after post-processing; In step (1), the pretreated electrode plate is prepared by the following method: The formed flexible graphite electrode plate is degassed to obtain a pretreated electrode plate. In step (2), during the pressurization process, the pressurization rate is 0.5-5 MPa / s; the pressure inside the cold isostatic working tank is pressurized to 10-600 MPa; In step (3), the pressure holding time is 0.5-60 min; In step (4), the depressurization rate is 1-5 MPa / s during the depressurization process.

2. A process for impregnating a flexible graphite pole plate for a fuel cell according to claim 1, characterized by, In step (1), the incompressible fluid is selected from one or more of liquid thermosetting resin, hydraulic oil or water.

3. A method of impregnating a flexible graphite polar plate for a fuel cell according to claim 2, wherein The thermosetting resin is selected from one or more of acrylic resins, vinyl resins, or epoxy resins.

4. The method of claim 2, wherein the graphite sheet is impregnated with the pitch by a method comprising: The thermosetting resin is an unsaturated resin system.

5. The impregnation method for a flexible graphite electrode plate for a fuel cell according to claim 1, characterized in that, In step (5), the post-processing is cleaning and curing.