CN117254053B - High-conductivity bipolar plate and preparation method and application thereof - Google Patents
High-conductivity bipolar plate and preparation method and application thereof Download PDFInfo
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- 238000002360 preparation method Methods 0.000 title claims abstract description 20
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- 238000002156 mixing Methods 0.000 claims abstract description 52
- 229910002804 graphite Inorganic materials 0.000 claims abstract description 51
- 239000010439 graphite Substances 0.000 claims abstract description 51
- 239000002245 particle Substances 0.000 claims abstract description 48
- 229920002313 fluoropolymer Polymers 0.000 claims abstract description 42
- 238000000034 method Methods 0.000 claims abstract description 42
- 239000000843 powder Substances 0.000 claims abstract description 39
- 238000004519 manufacturing process Methods 0.000 claims abstract description 37
- 238000007731 hot pressing Methods 0.000 claims abstract description 24
- 238000001125 extrusion Methods 0.000 claims abstract description 16
- 238000007872 degassing Methods 0.000 claims abstract description 14
- 230000001007 puffing effect Effects 0.000 claims abstract description 13
- 239000000446 fuel Substances 0.000 claims abstract description 11
- 238000003490 calendering Methods 0.000 claims abstract description 9
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 9
- 238000009826 distribution Methods 0.000 claims abstract description 8
- 239000000463 material Substances 0.000 claims description 37
- 238000005096 rolling process Methods 0.000 claims description 19
- 238000005520 cutting process Methods 0.000 claims description 12
- 239000000428 dust Substances 0.000 claims description 12
- -1 polytrichlorofluoroethylene Polymers 0.000 claims description 12
- 230000005540 biological transmission Effects 0.000 claims description 9
- 239000011812 mixed powder Substances 0.000 claims description 9
- 239000002033 PVDF binder Substances 0.000 claims description 8
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 8
- 239000004744 fabric Substances 0.000 claims description 7
- 229920001780 ECTFE Polymers 0.000 claims description 6
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 claims description 6
- 238000004321 preservation Methods 0.000 claims description 6
- 239000002994 raw material Substances 0.000 abstract description 12
- 239000007788 liquid Substances 0.000 abstract description 10
- 238000010924 continuous production Methods 0.000 abstract description 7
- 238000010008 shearing Methods 0.000 abstract description 7
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- 230000000052 comparative effect Effects 0.000 description 7
- 230000007547 defect Effects 0.000 description 5
- 238000012360 testing method Methods 0.000 description 5
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- 229910052731 fluorine Inorganic materials 0.000 description 4
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/0204—Non-porous and characterised by the material
- H01M8/0223—Composites
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0234—Carbonaceous material
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- H—ELECTRICITY
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- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/02—Details
- H01M8/0202—Collectors; Separators, e.g. bipolar separators; Interconnectors
- H01M8/023—Porous and characterised by the material
- H01M8/0239—Organic resins; Organic polymers
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
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- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M8/00—Fuel cells; Manufacture thereof
- H01M8/18—Regenerative fuel cells, e.g. redox flow batteries or secondary fuel cells
- H01M8/184—Regeneration by electrochemical means
- H01M8/188—Regeneration by electrochemical means by recharging of redox couples containing fluids; Redox flow type batteries
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Abstract
The invention provides a high-conductivity bipolar plate and a preparation method and application thereof, which take expandable graphite and fluoroplastic micro powder particles as raw materials, and prepare the high-conductivity bipolar plate through the procedures of high-temperature puffing, air flow mixing, degassing, conveyor belt distribution, preliminary belt extrusion, continuous roller calendaring, trimming, slitting and hot pressing, wherein the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance and can be widely used for various electrochemical-based water-based flow batteries and fuel cells; compared with the prior art, the continuous production among the steps of the invention improves the production efficiency, shortens the production time, reduces the production cost and is convenient for realizing industrial large-scale continuous batch production; the working procedures work together, so that the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance, and the power density and the service life of the water-based flow battery and the fuel battery are greatly improved; belongs to the technical field of batteries.
Description
Technical Field
The invention relates to the technical field of batteries, in particular to a high-conductivity bipolar plate and a preparation method and application thereof.
Background
The battery bipolar plate is classified into a metal bipolar plate, a graphite bipolar plate, and a composite bipolar plate according to the materials. Among them, graphite bipolar plates have good conductivity and corrosion resistance, and have been widely used in the field of batteries. The expanded graphite is a loose and porous worm-shaped substance obtained by intercalation, washing, drying and high-temperature puffing of natural graphite flakes, has the excellent properties of cold and heat resistance, corrosion resistance, self-lubrication and the like of natural graphite, and also has the characteristics of softness, compression rebound resilience, plasticity, adsorptivity, ecological environment harmony, biocompatibility, radiation resistance and the like which are not possessed by the natural graphite, so that the expanded graphite is commonly used for producing bipolar plates of energy storage flow batteries and fuel cells.
Because of the poor mechanical strength and leakage resistance of expanded graphite, it is often necessary to add resins to enhance its performance. The current method for preparing the bipolar plate by taking the expanded graphite and the resin as raw materials mainly comprises a wet mixing method and a dry mixing method. The Chinese patent CN107046140B discloses a fluorine-containing bipolar plate and a preparation method thereof, wherein expandable graphite and fluorine-containing polymer suspension emulsion are used as raw materials, and the fluorine-containing bipolar plate is obtained through mixing, drying, secondary crushing and sieving, continuous roller cold pressing and vacuum hot pressing treatment. The method solves the problem of dispersion uniformity of the fluororesin in the graphite by adopting a wet mixing method, improves the conductivity of the bipolar plate, but the method has the advantages of complex process flow, high production cost due to the need of a large amount of solvents, unsuitability for large-scale continuous production, and limited conductivity of the bipolar plate prepared by the method up to 285S/cm. The Chinese patent CN111261893B discloses a high-conductivity flexible graphite bipolar plate for a flow battery and preparation and application thereof, wherein expanded graphite and PVDF powder are used as raw materials, and the graphite bipolar plate is obtained through mixing, pressing, vacuum hot press molding or calendaring molding. The method adopts a dry mixing method, the preparation method is simple, the production process is easy to control, but the method has limited mixing uniformity of the expanded graphite and PVDF powder, and is easy to cause defects such as cracks and the like of the bipolar plate, so that the production quality of the bipolar plate is poor, the service life is short, and in addition, the conductivity of the bipolar plate prepared by the method is up to 250S/cm at most, and the conductivity is still poor. The above problems are to be solved.
Disclosure of Invention
In order to solve the technical problems, the technical scheme adopted by the application is to provide the high-conductivity bipolar plate and the preparation method and application thereof, so as to solve the technical problems of poor conductivity, poor production quality, high production cost and unsuitability for large-scale continuous production of the existing graphene bipolar plate.
A first aspect of an embodiment of the present application provides a method for manufacturing a highly conductive bipolar plate, including the steps of:
(1) Puffing: puffing the expandable graphite at high temperature to obtain graphite worms;
(2) Mixing: mixing and degassing graphite worms and fluoroplastic micro powder particles to obtain mixed powder;
(3) Cloth: distributing the mixed powder to obtain a material belt;
(4) And (3) forming: primarily extruding the material belt to obtain a blank coiled material, and then calendaring the blank coiled material to obtain a finished coiled material;
(5) Cutting: cutting the finished coiled material into product plates;
(6) Hot pressing: and hot-pressing the product plate into the high-conductivity bipolar plate.
Preferably, in the step (1), the purity of the expandable graphite is 95-99.95%, and the granularity is 32-80 meshes; the high-temperature puffing temperature is 500-950 ℃, and the volume expansion rate of the expandable graphite is 80-300 times.
Preferably, in the step (2), the fluoroplastic micro powder particles are any one of polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytrichloroethylene and ethylene-chlorotrifluoroethylene copolymer, and the particle size of the fluoroplastic micro powder particles is 1-50 μm.
Preferably, in the step (2), when the fluoroplastic micro powder particles are polyvinylidene fluoride, the addition amount is 10-20wt% of the total amount after mixing; when the fluoroplastic micro powder particles are ethylene-tetrafluoroethylene copolymer, the addition amount is 11-21 wt% of the total amount after mixing; when the fluoroplastic micro powder particles are polytrichlorofluoroethylene, the addition amount is 5-18wt% of the total amount after mixing; when the fluoroplastic micropowder particles are ethylene-chlorotrifluoroethylene copolymer, the addition amount is 11-21 wt% of the total amount after mixing.
Preferably, in the step (2), the graphite worms and the fluoroplastic micro powder particles are mixed by adopting air flow in the mixing process, the air flow pressure in the feeding process is 0.01-0.3 MPa, the air flow pressure in the mixing process is 0.1-1 MPa, and the mixing time is 1-15 s; and (3) degassing by adopting a cyclone dust collector after mixing, wherein the air flow pressure of the cyclone dust collector is 0.01-0.5 MPa.
Preferably, in the step (3), the mixed powder is paved on a conveyor belt during material distribution to obtain a material belt, the conveying speed of the conveyor belt is 0.1-2 m/min, the thickness of the material belt is 10-50 cm, and the density of the material belt is 0.1-0.5 g/cm 3.
Preferably, in the step (4), a belt is adopted for extrusion in preliminary extrusion, the transmission speed of the belt and the transmission speed of the conveyor belt are both 0.1-2 m/min, the extrusion pressure is 1-5 MPa, the thickness of the blank coiled material is 1-5 cm, and the density is 0.8-1.5 g/cm 3; the continuous rolling is carried out by adopting a roller in the rolling time delay, the rotating speed of the roller is 0.2-2 m/min, the rolling pressure is 1-8 MPa, the thickness of the finished coiled material is 0.2-2 mm, and the density is 1.5-1.8 g/cm 3.
Preferably, in the step (6), when the fluoroplastic micro powder particles are polyvinylidene fluoride, the hot pressing temperature is 170-230 ℃; when the fluoroplastic micropowder particles are ethylene-tetrafluoroethylene copolymer, the hot pressing temperature is 260-320 ℃; when the fluoroplastic micropowder particles are polytrichlorofluoroethylene, the hot pressing temperature is 210-270 ℃; when the fluoroplastic micropowder particles are ethylene-chlorotrifluoroethylene copolymer, the hot-pressing temperature is 240-300 ℃; the hot pressing pressure is 5-25 MPa, and the heat preservation and pressure maintaining time is 1-4 h; the thickness of the high-conductivity bipolar plate is 0.5-1.0 mm, and the density is 1.70-1.85 g/cm 3.
The second aspect of the embodiment of the application provides the high-conductivity bipolar plate prepared by the preparation method of any one of the above.
A third aspect of the embodiments of the present application provides an application of the highly conductive bipolar plate prepared by the preparation method described in any one of the above in water-based flow batteries and fuel cells.
The invention provides a high-conductivity bipolar plate and a preparation method and application thereof, which take expandable graphite and fluoroplastic micro powder particles as raw materials, and prepare the high-conductivity bipolar plate through the procedures of high-temperature puffing, air flow mixing, degassing, conveyor belt distribution, preliminary belt extrusion, continuous roller calendaring, trimming, slitting and hot pressing, wherein the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance and can be widely used for various electrochemical-based water-based flow batteries and fuel cells;
Compared with the prior art, the invention has the beneficial effects that:
(1) According to the invention, by adopting an air flow mixing mode, fluoroplastic micro powder particles are adhered to the surface of graphite worms, so that the raw materials are uniformly mixed in a short time, the mixing efficiency is improved, the mixing time is shortened, and the industrial mass production is convenient to realize; in addition, the high uniform mixing of the raw materials improves the overall uniformity of the bipolar plate, so that the conductivity, the mechanical strength and the service life of the bipolar plate are greatly improved, the addition amount of fluoroplastic micro powder particles is reduced, and the conductivity of the bipolar plate is further improved;
(2) According to the invention, the cyclone dust collector is adopted to carry out degassing on the mixed materials, so that the pressure of the mixed air flow is reduced, the gas-solid speed reduction separation is realized, and the stability of the material distribution process of the conveyor belt is ensured; in addition, the defects of holes and the like on the surface of the bipolar plate caused by the heated volatilization of the gas in the hot pressing process can be avoided after the degassing, and the production quality of the bipolar plate is improved, so that the mechanical strength and the service life of the bipolar plate are improved;
(3) According to the invention, by adopting a twice molding process of belt preliminary extrusion and roller continuous rolling, three working procedures of belt cloth, belt preliminary extrusion and roller continuous rolling are connected, and continuous production is realized by extruding and rolling the cloth, so that the production efficiency is improved, and the production time is shortened;
(4) The hot pressing process of the invention sets the heat preservation and pressure maintaining time of 1-4 hours, so that heated and melted fluoroplastic micro powder particles have enough time to flow, fully enter between layers of graphite and in pores of graphite worms, realize the full cross-linking and solidification of the graphite worms and the fluoroplastic micro powder particles, and improve the conductivity and mechanical strength of the bipolar plate on the premise of low addition of the fluoroplastic micro powder particles; in addition, the sufficient heat preservation and pressure maintaining time is favorable for timely discharging residual gas in the bipolar plate, avoids defects on the surface of the bipolar plate, and further improves the mechanical strength, the liquid resistance and the service life of the bipolar plate;
(5) The high-temperature puffing furnace, the powder adding machine, the mixing pipeline, the cyclone dust collector, the material distributor, the conveyor belt, the calender and the circular cutting machine are sequentially connected to form a production line, and the continuous production among the steps is realized, so that the production efficiency is improved, the production time is shortened, the production cost is reduced, and the large-scale continuous batch production in industry is conveniently realized; the working procedures work together to ensure that the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance, the conductivity is up to 423S/cm, the tensile strength is up to 35MPa, the compressive strength is up to 42MPa, the bending strength is up to 33MPa, and the power density and the service life of the water-based flow battery and the fuel battery are greatly improved.
Detailed Description
In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the application is further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the application. The raw materials and the devices used in the application are all conventional commercial products if no special regulations exist; the methods used, unless otherwise specified, are all conventional.
In order to confirm the reliability of the effect of the present invention, the present invention will be described below with reference to examples and comparative examples.
Examples 1-12 illustrate highly conductive bipolar plates and methods of making the same.
Table 1 preparation process parameters of highly conductive bipolar plates of examples 1 to 12
The preparation method of the high-conductivity bipolar plates of the above embodiments 1 to 12 comprises the following steps:
(1) Puffing: weighing expandable graphite with purity of 99% and granularity of 50 meshes according to the addition amount of examples 1-12 in Table 1, and carrying out high-temperature expansion on the expandable graphite at 800 ℃ by adopting a high-temperature expansion furnace to obtain graphite worms with volume expansion multiplying power of 200 times;
(2) Mixing: weighing fluoroplastic micro powder particles with the particle size of 30 mu m according to the types and the addition amounts of examples 1-12 in Table 1, adding graphite worms into a mixing pipeline by adopting a powder adding machine, simultaneously adding the fluoroplastic micro powder particles, mixing the graphite worms and the fluoroplastic micro powder particles in the mixing pipeline by adopting air flow, setting the air flow pressure at the feeding time to be 0.1MPa, the air flow pressure at the mixing time to be 0.5MPa, and the mixing time to be 2-3 s; degassing by adopting a cyclone dust collector after mixing, setting the air flow pressure of the cyclone dust collector to be 0.2MPa, and obtaining mixed powder after degassing;
(3) Cloth: distributing the mixed powder by a distributing machine, and spreading the mixed powder on a conveyor belt with the transmission speed of 0.5m/min to obtain a material belt with the thickness of 10-50 cm and the density of 0.1-0.5 g/cm 3;
(4) And (3) forming: the material belt on the conveyor belt is primarily extruded by adopting the belt, the transmission speed of the belt and the conveyor belt is set to be 0.5m/min, the extrusion pressure is 5MPa, and the blank coiled material with the thickness of 1-5 cm and the density of 0.8-1.5 g/cm 3 is obtained; then adopting a calender to calender the blank coiled material in a continuous roller rolling mode, setting the rotation speed of the roller to be 0.5m/min and the calendering pressure to be 8MPa, and trimming by adopting a trimming machine while calendering in the calendering process to obtain a finished coiled material with the thickness of 0.2-2 mm and the density of 1.5-1.8 g/cm 3;
(5) Cutting: dividing the finished coiled material into product plates by a circular cutting machine according to the required size of the bipolar plate of the battery;
(6) Hot pressing: the product plates were hot-pressed according to the hot-pressing process of examples 1 to 12 in table 1 to obtain highly conductive bipolar plates having a thickness of 0.5 to 1.0mm and a density of 1.70 to 1.85g/cm 3, which were prepared according to the preparation process parameters of examples 1 to 12 in table 1.
The high conductivity bipolar plates prepared in examples 1 to 12 and the commercial bipolar plate of comparative example 1 were each subjected to performance test, and their electrical conductivity, tensile strength, compressive strength and flexural strength were measured. Wherein,
Comparative example 1: a commercial fuel cell bipolar plate is produced by a manufacturer, wherein the raw materials are a cell graphite plate and liquid resin.
Conductivity, tensile strength, compressive strength and flexural strength were measured as follows:
Conductivity: testing according to the specification of NB/T42007-2013 bipolar plate test method for all-vanadium redox flow batteries;
Tensile strength: according to JB/T9141.2-2013, part 2 of flexible graphite sheet: the tensile strength test method is specified for testing;
Compressive strength: testing according to the specification of GB/T13465.3-2014 compression strength test method of impermeable graphite material;
flexural strength: the test was carried out according to the specification of GB/T13465.2-2002 method for testing flexural Strength of impermeable graphite Material.
The performance test results of the highly conductive bipolar plates of examples 1 to 12 and the commercial bipolar plate of comparative example 1 are shown in table 2.
Table 2 results of performance tests of examples 1 to 12 and comparative example 1
From table 2 it can be seen that:
Compared with comparative example 1, the conductivity, tensile strength, compressive strength and bending strength of the highly conductive bipolar plates prepared in examples 1 to 12 are all superior to those of comparative example 1, and it is understood that the highly conductive bipolar plates prepared in examples 1 to 12 of the present invention not only maintain the ultra-high conductivity of the hard sintered graphite, but also maintain the excellent flexibility and compression resistance of the flexible graphite sheet, i.e., the highly conductive bipolar plates prepared in the preparation method of the present invention have excellent conductivity, flexibility, liquid resistance and shearing resistance, which are determined by the preparation method of the present invention.
Compared with the fluorine-containing bipolar plate disclosed in the Chinese patent No. CN107046140B and the graphite bipolar plate disclosed in the Chinese patent No. CN111261893B, the high-conductivity bipolar plate prepared by the preparation method provided by the invention has the conductivity of 281-423S/cm and shows excellent high conductivity.
The high-conductivity bipolar plate prepared by the preparation method disclosed by the invention is applied to water-based flow batteries and fuel cells.
The invention provides a high-conductivity bipolar plate and a preparation method and application thereof, which take expandable graphite and fluoroplastic micro powder particles as raw materials, and prepare the high-conductivity bipolar plate through the procedures of high-temperature puffing, air flow mixing, degassing, conveyor belt distribution, preliminary belt extrusion, continuous roller calendaring, trimming, slitting and hot pressing, wherein the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance and can be widely used for various electrochemical-based water-based flow batteries and fuel cells;
Compared with the prior art, (1) the fluoroplastic micro powder particles are adhered to the surfaces of graphite worms by adopting an air flow mixing mode, so that the high-uniformity mixing of raw materials is realized in a short time, the mixing efficiency is improved, the mixing time is shortened, and the industrial mass production is convenient to realize; in addition, the high uniform mixing of the raw materials improves the overall uniformity of the bipolar plate, so that the conductivity, the mechanical strength and the service life of the bipolar plate are greatly improved, the addition amount of fluoroplastic micro powder particles is reduced, and the conductivity of the bipolar plate is further improved; (2) According to the invention, the cyclone dust collector is adopted to carry out degassing on the mixed materials, so that the pressure of the mixed air flow is reduced, the gas-solid speed reduction separation is realized, and the stability of the material distribution process of the conveyor belt is ensured; in addition, the defects of holes and the like on the surface of the bipolar plate caused by the heated volatilization of the gas in the hot pressing process can be avoided after the degassing, and the production quality of the bipolar plate is improved, so that the mechanical strength and the service life of the bipolar plate are improved; (3) According to the invention, by adopting a twice molding process of belt preliminary extrusion and roller continuous rolling, three working procedures of belt cloth, belt preliminary extrusion and roller continuous rolling are connected, and continuous production is realized by extruding and rolling the cloth, so that the production efficiency is improved, and the production time is shortened; (4) The hot pressing process of the invention sets the heat preservation and pressure maintaining time of 1-4 hours, so that heated and melted fluoroplastic micro powder particles have enough time to flow, fully enter between layers of graphite and in pores of graphite worms, realize the full cross-linking and solidification of the graphite worms and the fluoroplastic micro powder particles, and improve the conductivity and mechanical strength of the bipolar plate on the premise of low addition of the fluoroplastic micro powder particles; in addition, the sufficient heat preservation and pressure maintaining time is favorable for timely discharging residual gas in the bipolar plate, avoids defects on the surface of the bipolar plate, and further improves the mechanical strength, the liquid resistance and the service life of the bipolar plate; (5) The high-temperature puffing furnace, the powder adding machine, the mixing pipeline, the cyclone dust collector, the material distributor, the conveyor belt, the calender and the circular cutting machine are sequentially connected to form a production line, and the continuous production among the steps is realized, so that the production efficiency is improved, the production time is shortened, the production cost is reduced, and the large-scale continuous batch production in industry is conveniently realized; the working procedures work together, so that the high-conductivity bipolar plate has excellent conductivity, flexibility, liquid resistance and shearing resistance, the conductivity is up to 423S/cm, the tensile strength is up to 35MPa, the compressive strength is up to 42MPa, the bending strength is up to 33MPa, and the power density and the service life of the water-based flow battery and the fuel battery are greatly improved; can be widely applied to the technical field of batteries.
It should be noted that:
(1) In the above embodiment, the purity of the expandable graphite is 99%, the particle size is 50 mesh, and only as a preferred embodiment, in actual production, the purity of the expandable graphite may be 95-99.95%, the particle size may be 32-80 mesh, and in actual operation, the expandable graphite is adaptively adjusted according to specific conditions.
(2) In the above embodiment, the high temperature expansion temperature of the expandable graphite is 800 ℃, the volume expansion rate of the expandable graphite after high temperature expansion is 200 times, and only as a preferred embodiment, in actual production, the high temperature expansion temperature may be 500-950 ℃, the volume expansion rate of the expandable graphite may be 80-300 times, and the expansion rate may be adaptively adjusted according to actual conditions.
(3) In the above embodiment, the particle size of the fluoroplastic fine particles is 30. Mu.m, but as a preferred embodiment, the particle size of the fluoroplastic fine particles may be 1 to 50. Mu.m.
(4) In the above embodiment, during the mixing process, the air pressure during feeding is 0.1MPa, the air pressure during mixing is 0.5MPa, the mixing time is 2-3 s, the air pressure of the cyclone dust collector during degassing is 0.5MPa, which is just a preferred embodiment, during actual production, the air pressure during feeding may be 0.01-0.3 MPa, the air pressure during mixing may be 0.1-1 MPa, the mixing time may be 1-15 s, the air pressure of the cyclone dust collector during degassing may be 0.01-0.5 MPa, and the adaptive adjustment is performed according to the actual situation.
(5) In the above embodiment, in the material distribution process, the transmission speed of the conveyor belt is 0.5m/min, in the preliminary extrusion process, the transmission speeds of the belt and the conveyor belt are both 0.5m/min, and the extrusion pressure is 5MPa, which is just a preferred embodiment, in the actual production, the transmission speed of the conveyor belt may be 0.1-2 m/min, the transmission speed of the belt may be 0.1-2 m/min, and the extrusion pressure may be 1-5 MPa, and the adaptive adjustment is performed according to the actual situation.
(6) In the above embodiment, the rolling speed of the roller is 0.5m/min and the rolling pressure is 8MPa in the rolling process, which is just a preferred embodiment, and in actual production, the rolling speed of the roller may be 0.2-2 m/min and the rolling pressure may be 1-8 MPa, and the rolling pressure is adaptively adjusted according to actual conditions.
(7) The powder adding machine adopted in the embodiment is a bipolar plate static-removing powder adding machine disclosed by a patent CN213010871U, the material distributing machine adopted is a graphite powder distributing machine disclosed by a patent CN207618672U, the calender adopted is a bipolar plate calender disclosed by a patent CN207681168U, the edge cutting machine adopted is a bipolar plate edge cutting machine disclosed by a patent CN207616102U, and the circular cutting machine adopted is a bipolar plate circular cutting machine disclosed by a patent CN 213351006U.
The above embodiments are only for illustrating the technical solution of the present application, and not for limiting the same; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.
Claims (10)
1. The preparation method of the high-conductivity bipolar plate is characterized by comprising the following steps of:
(1) Puffing: puffing the expandable graphite at high temperature to obtain graphite worms;
(2) Mixing: mixing and degassing graphite worms and fluoroplastic micro powder particles to obtain mixed powder; when mixing, adopting air flow to mix graphite worms with fluoroplastic micro powder particles in a mixing pipeline, and adopting a cyclone dust collector to remove gas after mixing;
(3) Cloth: distributing the mixed powder to obtain a material belt;
(4) And (3) forming: primarily extruding the material belt to obtain a blank coiled material, and then calendaring the blank coiled material to obtain a finished coiled material;
(5) Cutting: cutting the finished coiled material into product plates;
(6) Hot pressing: and hot-pressing the product plate into the high-conductivity bipolar plate.
2. The method for producing a highly conductive bipolar plate according to claim 1, wherein in step (1), the purity of the expandable graphite is 95 to 99.95%, and the particle size is 32 to 80 mesh; the high-temperature puffing temperature is 500-950 ℃, and the volume expansion rate of the expandable graphite is 80-300 times.
3. The method for producing a highly conductive bipolar plate according to claim 1, wherein in the step (2), the fluoroplastic micro powder particles are any one of polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, polytrichlorofluoroethylene, and ethylene-chlorotrifluoroethylene copolymer, and the particle size of the fluoroplastic micro powder particles is 1 to 50. Mu.m.
4. The method for producing a highly conductive bipolar plate according to claim 3, wherein in the step (2), when the fluoroplastic micro powder particles are polyvinylidene fluoride, the addition amount thereof is 10to 20wt% of the total amount after mixing;
when the fluoroplastic micro powder particles are ethylene-tetrafluoroethylene copolymer, the addition amount is 11-21 wt% of the total amount after mixing;
when the fluoroplastic micro powder particles are polytrichlorofluoroethylene, the addition amount is 5-18wt% of the total amount after mixing;
When the fluoroplastic micropowder particles are ethylene-chlorotrifluoroethylene copolymer, the addition amount is 11-21 wt% of the total amount after mixing.
5. The method for producing a highly conductive bipolar plate according to claim 1, wherein in step (2), the gas flow pressure at the time of feeding is 0.01 to 0.3MPa, the gas flow pressure at the time of mixing is 0.1 to 1MPa, and the mixing time is 1 to 15s; the airflow pressure of the cyclone dust collector is 0.01-0.5 MPa.
6. The method for producing a highly conductive bipolar plate according to claim 1, wherein in step (3), the mixed powder is spread on a conveyor belt during the distribution to obtain a material belt, the conveying speed of the conveyor belt is 0.1-2 m/min, the thickness of the material belt is 10-50 cm, and the density is 0.1-0.5 g/cm 3.
7. The method for producing a highly conductive bipolar plate according to claim 6, wherein in step (4), the preliminary extrusion is performed by using a belt, the transmission speeds of the belt and the conveyor belt are both 0.1 to 2m/min, the extrusion pressure is 1 to 5MPa, the thickness of the blank coiled material is 1 to 5cm, and the density is 0.8 to 1.5g/cm 3;
The continuous rolling is carried out by adopting a roller in the rolling time delay, the rotating speed of the roller is 0.2-2 m/min, the rolling pressure is 1-8 MPa, the thickness of the finished coiled material is 0.2-2 mm, and the density is 1.5-1.8 g/cm 3.
8. The method for producing a highly conductive bipolar plate according to claim 3, wherein in step (6), when the fluoroplastic micro powder particles are polyvinylidene fluoride, the hot pressing temperature is 170 to 230 ℃;
When the fluoroplastic micropowder particles are ethylene-tetrafluoroethylene copolymer, the hot pressing temperature is 260-320 ℃;
when the fluoroplastic micropowder particles are polytrichlorofluoroethylene, the hot pressing temperature is 210-270 ℃;
when the fluoroplastic micropowder particles are ethylene-chlorotrifluoroethylene copolymer, the hot-pressing temperature is 240-300 ℃;
the hot pressing pressure is 5-25 MPa, and the heat preservation and pressure maintaining time is 1-4 h;
The thickness of the high-conductivity bipolar plate is 0.5-1.0 mm, and the density is 1.70-1.85 g/cm 3.
9. A highly conductive bipolar plate prepared by the method of any one of claims 1-8.
10. Use of a highly conductive bipolar plate prepared by the method of any one of claims 1-8 in water-based flow batteries and fuel cells.
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