Soluble modified polyarylsulfonyl high-temperature-resistant composite bipolar plate and preparation method thereof

Abstract

The invention belongs to the technical field of hydrogen fuel cell preparation, and particularly relates to a soluble modified polyarylsulfonyl high-temperature-resistant composite bipolar plate and a preparation method thereof. The soluble modified polyarylsulfonyl high-temperature-resistant composite bipolar plate is prepared from the following raw materials in parts by weight: 70-95% of conductive matrix and 5-30% of binder, and the binder is a soluble high-temperature-resistant modified polysulfone high polymer material. The high-temperature-resistant composite bipolar plate obtained by the invention is low in production energy consumption and high in processing efficiency. A high-temperature-resistant stability test proves that the performance stability is greatly improved, and the application requirements of high-temperature fuel cells are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrogen fuel cell preparation, and in particular relates to a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate and a preparation method thereof. Background Art

[0002] With the growing global demand for clean energy, proton exchange membrane fuel cells (PEMFCs) have attracted widespread attention for their high conversion efficiency, pollution-free, and renewable fuel characteristics. There are two types of proton exchange membrane fuel cells: low-temperature hydrogen fuel cells (LT-PEMFCs) and high-temperature hydrogen fuel cells (HT-PEMFCs). In contrast, HT-PEMFCs operating under high temperature conditions have faster electrode reaction kinetics and higher energy conversion efficiency; the catalyst's tolerance to impurity gases such as CO in the raw materials is significantly enhanced (CO content <25pm, 80℃; CO content <1000pm, 130℃; CO content <3000pm, 200℃), thereby reducing the requirements for H2 purity and further broadening the range of fuel choices; in addition, when the operating temperature is higher than 100℃, most of the water inside the battery exists in gaseous form, which is easy to discharge, and the temperature difference with the surrounding environment is large, which can greatly simplify the water management system and thermal management system.

[0003] In order to promote the application of high-temperature proton exchange membrane fuel cells, it is urgent to develop high-temperature resistant and low-cost key materials and components for hydrogen fuel cells. Bipolar plates can distribute reaction gases, provide fluid channels, conduct electricity and heat, and support membrane electrodes. They are the skeleton and foundation of fuel cells. However, the existing high-temperature resistant bipolar plates have the disadvantage of high cost. Composite bipolar plates can significantly reduce costs, but traditional composite bipolar plates have poor high-temperature resistance. It is of great practical significance to develop a composite bipolar plate for high-temperature hydrogen fuel cells with superior performance and low cost.

[0004] In view of this, the present invention is proposed. Summary of the invention

[0005] The object of the present invention is to provide a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate and a preparation method thereof to solve the above problems.

[0006] In order to achieve the above objectives, the present invention particularly adopts the following technical solutions:

[0007] The present invention provides a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, characterized in that the raw materials of the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate include:

[0008] By weight, the conductive matrix is ​​70-95% and the binder is 5-30%, wherein the binder is a soluble high temperature resistant modified polysulfone polymer material.

[0009] Preferably, the conductive substrate is a graphite material, preferably high-purity graphite or expanded graphite, wherein the carbon content in the high-purity graphite is above 99%.

[0010] Preferably, the soluble high temperature resistant modified polysulfone polymer material is obtained by solution blending of polyarylsulfone and polyimide, and the mass ratio of polyarylsulfone to polyimide is 1:0.1-3.

[0011] The present invention provides a method for preparing the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, comprising the following steps:

[0012] 1) adding polyarylsulfone and polyimide into a solvent medium respectively to obtain a polyarylsulfone / polyimide mixed dispersion;

[0013] 2) adding the conductive matrix to the polyarylsulfone / polyimide mixed dispersion in step 1), and drying to obtain a polyarylsulfone / polyimide / conductive matrix premix;

[0014] 3) pouring the polyarylsulfone / polyimide / conductive matrix premix obtained in step 2) into a mold, pressurizing, heating, cooling, and demolding to obtain a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate.

[0015] Preferably, in step 1), the mass ratio of the total mass of the polyarylsulfone and the polyimide to the solvent medium is 1:2 to 10;

[0016] Preferably, the solvent medium in step 1) comprises N,N-dimethylacetamide.

[0017] Preferably, in step 2), the drying temperature is 50-150° C., and the drying time is 1-6 h.

[0018] Preferably, in step 3), the mold preheating temperature is 55-100° C., the pre-pressing pressure is 1-5 MPa, and the pre-pressing time is 1 to 20 min.

[0019] Preferably, in step 3), the molding temperature is 200-400° C., the molding pressure is 10-100 MPa, and the molding time is 5-200 min;

[0020] Preferably, in step 3), after the molding is completed and the mold temperature drops to 20-80° C., the pressure is released and the mold is demolded.

[0021] The invention mixes polyaryl sulfone and polyimide to obtain modified polyaryl sulfone resin, and then wet-mixes the resin with a conductive matrix, and finally obtains a high-temperature resistant composite bipolar plate through drying, molding and heat treatment.

[0022] Beneficial effects of the present invention:

[0023] The soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate obtained by the present invention has low production energy consumption and high processing efficiency. The high-temperature stability test proves that its performance stability is greatly improved, meeting the application requirements of high-temperature fuel cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0025] Figure 1 The graph of the change in flexural strength of the soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate before and after the high-temperature resistance test at different PAS and PI mass ratios (1:0.5, 1:0.75, 1:1, 1:1.25, 1:1.5 and 100% PI);

[0026] Figure 2 The conductivity change diagram of the soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate before and after the high-temperature resistance test at different PAS and PI mass ratios (1:0.5, 1:0.75, 1:1, 1:1.25, 1:1.5 and 100% PI).

[0027] Figure 3 It is a schematic diagram of the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] First, the present invention is explained as a whole, as follows:

[0030] The present invention provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, wherein a graphite material is used as a conductive matrix, a soluble high temperature resistant modified polysulfone polymer material is used as a binder, the conductive matrix mass fraction is 70-95%, and the binder mass fraction is 5-30%, and then the mixture is wet mixed to obtain a mixed material; and the mixed material is dried, molded and heat treated in sequence to finally obtain a high temperature resistant composite bipolar plate, such as Figure 3As shown; wherein, the modified polysulfone polymer material is obtained by a solution blending method of polyarylsulfone (PAS) and polyimide (PI), and the mass ratio of polyarylsulfone to polyimide is 1:0.1-3;

[0031] The polyarylsulfone and polyimide solution blending process and the wet mixing process use N,N-dimethylacetamide (DMAc) as a solvent medium; the mass ratio of the total mass of polyarylsulfone and polyimide to the solvent medium is 1:2-10.

[0032] Specifically, the present invention provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, comprising the following steps:

[0033] (1) Weighing graphite materials, polyarylsulfone and polyimide in proportion, adding polyarylsulfone and polyimide into a solvent medium respectively, and ultrasonically dispersing them in an ultrasonic disperser to obtain a polyarylsulfone / polyimide mixed dispersion. Then adding graphite materials and stirring evenly to finally obtain a polyarylsulfone / polyimide / graphite premixed slurry;

[0034] (2) treating the premixed slurry obtained in step (1) at 50-150° C. for 1-6 hours to obtain a dry polyarylsulfone / polyimide / graphite premix;

[0035] (3) Loading the dried graphite / polyarylsulfone / polyimide premix into a compression mold with a customized flow channel, ensuring that the mixture is flat and uniform, and then closing the mold. The mold preheating temperature is 55-100° C., the pre-pressing pressure is 1-5 MPa, the pre-pressing time is 1-20 min, the molding temperature is 200-400° C., the molding pressure is 10-100 MPa, and the molding time is 5-200 min;

[0036] (4) After the molding is completed, when the mold temperature drops to 20-80° C., the pressure is released and the mold is demolded to obtain the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate.

[0037] Example 1

[0038] This embodiment 1 provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, which is as follows:

[0039] (1) Preparation of polysulfone / polyimide mixed dispersion

[0040] According to the mass ratio of polyaryl sulfone to polyimide of 1:0.5 and the mass ratio of the total mass of polyaryl sulfone and polyimide to N,N-dimethylacetamide of 1:5, weigh the corresponding masses of polyaryl sulfone, polyimide and N,N-dimethylacetamide, pour the polyaryl sulfone and polyimide into the N,N-dimethylacetamide organic solvent successively, and stir ultrasonically for 20 minutes to fully dissolve the materials.

[0041] (2) Preparation of polysulfone / polyimide / high-purity graphite premix

[0042] According to the proportion of 70% mass fraction of conductive matrix (high-purity graphite) and 30% mass fraction of binder (polyarylsulfone and polyimide), high-purity graphite is weighed, and high-purity graphite is added to the polyarylsulfone / polyimide mixed dispersion, and the mixed slurry is stirred in a high-speed stirrer for 15 minutes to make the polyarylsulfone / polyimide evenly coated on the surface of high-purity graphite to obtain polyarylsulfone / polyimide / high-purity graphite mixed slurry. After stirring, it is dried in a blast oven at 100°C for 3 hours, and then the dried polyarylsulfone / polyimide / high-purity graphite premix is ​​transferred to a preheated molding mold.

[0043] (3) Loading, molding and heat treatment

[0044] The polyarylsulfone / polyimide / high-purity graphite premix obtained in step (2) is poured into a 90°C mold, and the surface of the material is smoothed with a scraper. After the mold is closed, the pressure is increased to 1 MPa and maintained for 5 minutes. The temperature is then increased to 250°C, and the molding pressure is maintained at 30 MPa for 30 minutes. After naturally cooling to 80°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate.

[0045] Example 2

[0046] This embodiment 2 provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, which is as follows:

[0047] (1) Preparation of polysulfone / polyimide mixed dispersion

[0048] According to the mass ratio of polyaryl sulfone to polyimide of 1:0.75 and the mass ratio of the total mass of polyaryl sulfone and polyimide to N,N-dimethylacetamide of 1:6, the corresponding masses of polyaryl sulfone, polyimide and N,N-dimethylacetamide were weighed, and the polyaryl sulfone and polyimide were poured into the N,N-dimethylacetamide organic solvent in turn, and ultrasonic stirring was carried out for 20 minutes to fully dissolve the materials.

[0049] (2) Preparation of polysulfone / polyimide / high-purity graphite premix

[0050] According to the proportion of 80% mass fraction of conductive matrix (high-purity graphite) and 20% mass fraction of binder (polyarylsulfone and polyimide), high-purity graphite is weighed, and high-purity graphite is added to the polyarylsulfone / polyimide mixed dispersion, and the mixed slurry is stirred in a high-speed stirrer for 15 minutes to make the polyarylsulfone / polyimide evenly coated on the surface of high-purity graphite to obtain polyarylsulfone / polyimide / high-purity graphite mixed slurry. After stirring, it is dried in a blast oven at 110°C for 4 hours, and then the dried polyarylsulfone / polyimide / high-purity graphite premix is ​​transferred to a preheated molding mold.

[0051] (3) Loading, molding and heat treatment

[0052] The polyarylsulfone / polyimide / high-purity graphite premix obtained in step (2) is poured into a 100°C mold, and the surface of the material is smoothed using a scraper. After the mold is closed, the pressure is increased to 4 MPa and maintained for 1 min. The temperature is then increased to 300°C, and the molding pressure is maintained at 50 MPa for 50 min. After naturally cooling to 70°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate.

[0053] Example 3

[0054] This embodiment 3 provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, which is as follows:

[0055] (1) Preparation of polysulfone / polyimide mixed dispersion

[0056] According to the mass ratio of polyaryl sulfone to polyimide of 1:0.75 and the mass ratio of the total mass of polyaryl sulfone and polyimide to N,N-dimethylacetamide of 1:5, the corresponding masses of polyaryl sulfone, polyimide and N,N-dimethylacetamide were weighed, and the polyaryl sulfone and polyimide were poured into the N,N-dimethylacetamide organic solvent in turn, and ultrasonic stirring was carried out for 20 minutes to fully dissolve the materials.

[0057] (2) Preparation of polysulfone / polyimide / high-purity graphite premix

[0058] According to the proportion of 90% mass fraction of conductive matrix (high-purity graphite) and 10% mass fraction of binder (polyarylsulfone and polyimide), high-purity graphite is weighed, and graphite is added to the polyarylsulfone / polyimide mixed dispersion, and the mixed slurry is stirred in a high-speed stirrer for 15 minutes to make the polyarylsulfone / polyimide evenly coated on the surface of high-purity graphite to obtain polyarylsulfone / polyimide / high-purity graphite mixed slurry. After stirring, it is dried in a blast oven at 150°C for 1 hour, and then the dried polyarylsulfone / polyimide / high-purity graphite premix is ​​transferred to a preheated molding mold.

[0059] (3) Loading, molding and heat treatment

[0060] The polyarylsulfone / polyimide / high-purity graphite premix obtained in step (2) is poured into a 60°C mold, and the surface of the material is smoothed with a scraper. After the mold is closed, the pressure is increased to 2.5 MPa and maintained for 20 minutes. The temperature is then raised to 200°C, and the molding pressure is maintained at 10 MPa for 5 minutes. After naturally cooling to 30°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate.

[0061] Example 4

[0062] This embodiment 4 provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, which is as follows:

[0063] (1) Preparation of polysulfone / polyimide mixed dispersion

[0064] According to the mass ratio of polyaryl sulfone to polyimide of 1:1.25 and the mass ratio of the total mass of polyaryl sulfone and polyimide to N,N-dimethylacetamide of 1:10, the corresponding masses of polyaryl sulfone, polyimide and N,N-dimethylacetamide were weighed, and the polyaryl sulfone and polyimide were poured into the N,N-dimethylacetamide organic solvent in turn, and ultrasonic stirring was carried out for 20 minutes to fully dissolve the materials.

[0065] (2) Preparation of polysulfone / polyimide / high-purity graphite premix

[0066] According to the proportion of 95% mass fraction of conductive matrix (high-purity graphite) and 5% mass fraction of binder (polyarylsulfone and polyimide), high-purity graphite is weighed, and graphite is added to the mixed dispersion of polyarylsulfone / polyimide, and the mixed slurry is stirred in a high-speed stirrer for 15 minutes to make polyarylsulfone / polyimide evenly coated on the surface of high-purity graphite to obtain polyarylsulfone / polyimide / high-purity graphite mixed slurry. After stirring, it is dried in a blast oven at 60°C for 6 hours, and then the dried polyarylsulfone / polyimide / high-purity graphite premix is ​​transferred to a preheated molding mold.

[0067] (3) Loading, molding and heat treatment

[0068] The polyarylsulfone / polyimide / high-purity graphite premix obtained in step (2) is poured into a 70°C mold, and the surface of the material is smoothed with a scraper. After the mold is closed, the pressure is increased to 5 MPa and maintained for 10 min. The temperature is then increased to 400°C, and the molding pressure is maintained at 100 MPa for 100 min. After naturally cooling to 20°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate.

[0069] Example 5

[0070] This embodiment 5 provides a method for preparing a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, which is specifically as follows:

[0071] (1) Preparation of polysulfone / polyimide mixed dispersion

[0072] According to the mass ratio of polyaryl sulfone to polyimide of 1:0.5 and the mass ratio of the total mass of polyaryl sulfone and polyimide to N,N-dimethylacetamide of 1:5, weigh the corresponding masses of polyaryl sulfone, polyimide and N,N-dimethylacetamide, pour the polyaryl sulfone and polyimide into the N,N-dimethylacetamide organic solvent successively, and stir ultrasonically for 20 minutes to fully dissolve the materials.

[0073] (2) Preparation of polyarylsulfone / polyimide / expanded graphite premix

[0074] Weigh the expanded graphite according to the ratio of 70% by mass fraction of the conductive matrix (expanded graphite) and 30% by mass fraction of the binder (polyarylsulfone and polyimide), add the expanded graphite to the polyarylsulfone / polyimide mixed dispersion, stir the mixed slurry in a high-speed stirrer for 15 minutes, so that the polyarylsulfone / polyimide is evenly coated on the graphite surface, and obtain the polyarylsulfone / polyimide / expanded graphite mixed slurry. After the stirring is completed, dry it in a blast oven at 100° C. for 3 hours, and then transfer the dried polyarylsulfone / polyimide / expanded graphite premix to a preheated molding die.

[0075] (3) Loading, molding and heat treatment

[0076] The polyarylsulfone / polyimide / expanded graphite premix obtained in step (2) is poured into a 90°C mold, and the surface of the material is smoothed using a scraper. After the mold is closed, the pressure is increased to 1 MPa and maintained for 5 minutes. The temperature is then increased to 250°C, and the molding pressure is maintained at 1 30 MPa for 30 minutes. After naturally cooling to 80°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate.

[0077] Comparative Example 1

[0078] (1) Preparation of polyimide dispersion

[0079] According to the mass ratio of polyimide to N,N-dimethylacetamide being 1:5, corresponding masses of polyimide and N,N-dimethylacetamide were weighed, and the polyimide was poured into the organic solvent of N,N-dimethylacetamide, and ultrasonically stirred for 20 minutes to fully dissolve the materials.

[0080] (2) Preparation of polyimide / high purity graphite premix

[0081] According to the proportion of 70% mass fraction of conductive matrix (high-purity graphite) and 30% mass fraction of binder (polyimide), high-purity graphite is weighed, and high-purity graphite is added to polyimide dispersion, and the mixed slurry is stirred in a high-speed stirrer for 15 minutes to make polyimide evenly coated on the surface of high-purity graphite to obtain polyimide / high-purity graphite mixed slurry. After stirring, it is dried in a blast oven at 100°C for 3 hours, and then the dried polyimide / high-purity graphite premix is ​​transferred to a preheated molding mold.

[0082] (3) Loading, molding and heat treatment

[0083] The polyimide / high-purity graphite premix obtained in step (2) is poured into a 90°C mold, and the surface of the material is smoothed using a scraper. After the mold is closed, the pressure is increased to 1 MPa and maintained for 5 minutes. The temperature is then increased to 250°C, and the molding pressure is maintained at 30 MPa for 30 minutes. After naturally cooling to 80°C, the mold is demolded to obtain a soluble modified polyarylsulfone-based high-temperature resistant composite bipolar plate.

[0084] The density, flexural strength and electrical conductivity of the bipolar plates obtained in the above embodiments 1-5 and comparative embodiment 1 were tested respectively. The bipolar plates obtained in the above embodiments 1-5 and comparative embodiment 1 were placed in a 200°C oven for a 15-day high temperature resistance test, and then their density, flexural strength and electrical conductivity were tested respectively.

[0085]

[0086] The present invention combines Table 1 and the attached Figure 1-2 It can be found that the performance indicators of the composite bipolar plate prepared by the present invention meet the relevant application requirements. The high temperature test results also show that its performance degradation rate is generally low, proving that its performance stability is good and meets the application requirements of high temperature fuel cells.

[0087] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate, characterized in that: The raw materials of the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate include: By weight, the conductive matrix is ​​70-95% and the binder is 5-30%, wherein the binder is a soluble high temperature resistant modified polysulfone polymer material.

2. The soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate according to claim 1, characterized in that: The conductive substrate is a graphite material, preferably high-purity graphite or expanded graphite.

3. The soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate according to claim 1, characterized in that: The soluble high temperature resistant modified polysulfone polymer material is obtained by using a solution blending method for polyarylsulfone and polyimide, and the mass ratio of polyarylsulfone to polyimide is 1:0.1-3.

4. A method for preparing the soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate according to claims 1-3, comprising the following steps: 1) adding polyarylsulfone and polyimide into a solvent medium respectively to obtain a polyarylsulfone / polyimide mixed dispersion; 2) adding the conductive matrix to the polyarylsulfone / polyimide mixed dispersion in step 1), and drying to obtain a polyarylsulfone / polyimide / conductive matrix premix; 3) pouring the polyarylsulfone / polyimide / conductive matrix premix obtained in step 2) into a mold, pressurizing, heating, cooling, and demolding to obtain a soluble modified polyarylsulfone-based high temperature resistant composite bipolar plate.

5. The preparation method according to claim 4, characterized in that: The mass ratio of the total mass of the polyarylsulfone and the polyimide to the solvent medium in step 1) is 1:2-10.

6. The preparation method according to claim 4, characterized in that: The solvent medium in step 1) includes N,N-dimethylacetamide.

7. The preparation method according to claim 4, characterized in that: In step 2), the drying temperature is 50-150° C. and the drying time is 1-6 hours.

8. The preparation method according to claim 4, characterized in that: In step 3), the mold preheating temperature is 55-100° C., the pre-pressing pressure is 1-5 MPa, and the pre-pressing time is 1 to 20 minutes.

9. The preparation method according to claim 4, characterized in that: In step 3), the molding temperature is 200-400° C., the molding pressure is 10-100 MPa, and the molding time is 5-200 min.

10. The preparation method according to claim 4, characterized in that: In step 3), after the molding is completed, the mold temperature drops to 20-80° C., and then the pressure is released and the mold is demolded.

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