CN111261891A - Weldable bipolar plate for flow battery and preparation and application thereof - Google Patents

Weldable bipolar plate for flow battery and preparation and application thereof Download PDF

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CN111261891A
CN111261891A CN201811451354.2A CN201811451354A CN111261891A CN 111261891 A CN111261891 A CN 111261891A CN 201811451354 A CN201811451354 A CN 201811451354A CN 111261891 A CN111261891 A CN 111261891A
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bipolar plate
carbon
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body layer
zinc
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刘涛
李先锋
张华民
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Dalian Institute of Chemical Physics of CAS
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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
    • H01M8/0241—Composites
    • H01M8/0245—Composites in the form of layered or coated products
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
    • 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
    • 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
    • H01M8/0239—Organic resins; Organic polymers
    • 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
    • H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
    • H01M8/0273—Sealing or supporting means around electrodes, matrices or membranes with sealing or supporting means in the form of a frame
    • 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
    • H01M8/0271—Sealing or supporting means around electrodes, matrices or membranes
    • H01M8/0286—Processes for forming seals
    • 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
    • H01M8/18—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
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
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    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells

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Abstract

The invention relates to a weldable bipolar plate for a flow battery, and preparation and application thereof. The bipolar plate has higher conductivity and low contact resistance in a contact area with an electrode material, so that the ohmic polarization of the battery is reduced, and the voltage efficiency of the battery is improved; the contact area of the electrode frame and the electrode frame has higher polymer content, so that enough high welding strength can be ensured during welding, and the sealing reliability of the galvanic pile is ensured.

Description

Weldable bipolar plate for flow battery and preparation and application thereof
Technical Field
The invention relates to the field of flow batteries in the chemical energy storage technology, in particular to a bipolar plate of a flow battery and a preparation method thereof.
Background
The all-vanadium redox flow battery has the advantages that the output power and the capacity are mutually independent, and the system design is flexible; the energy efficiency is high, the service life is long, the operation stability and reliability are high, and the self-discharge is low; the method has the advantages of large site selection freedom degree, no pollution, simple maintenance, low operation cost, high safety and the like, has wide development prospect in the aspect of scale energy storage, is considered as an effective method for solving the randomness and intermittent unsteady state characteristics of a solar energy and wind energy renewable energy power generation system and the like, and has important requirements in the construction of renewable energy power generation and an intelligent power grid.
The bipolar plate is used as a key component of the flow battery, plays a role of connecting single batteries in series to form an electric stack, and needs to have good conductivity, liquid resistance, chemical stability and certain mechanical strength. The bipolar plate material mainly used at present is a hard graphite plate and a carbon-plastic composite material. The hard graphite plate has the characteristics of high conductivity, good liquid resistance and good chemical stability, but the practical application of the hard graphite plate is limited due to high cost and poor mechanical property. The carbon-plastic composite material is a bipolar plate material which is widely concerned at present, and has the main advantages of simple processing, low cost and easy realization of large-scale production. However, such materials are less conductive and in order to increase the conductivity, the content of the conductive filler in the material needs to be increased. And the composite board becomes brittle due to the excessively high content of the conductive filler, and is not suitable for electric pile assembly.
In addition, the sealing of the current flow battery mainly adopts a fluororubber line sealing or surface sealing mode, so that the cost is high, the reliability is poor, and the leakage is easy to occur after the rubber is aged. Therefore, ultrasonic welding or laser welding is a good solution to weld the bipolar plate and the electrode frame together. However, the composite board with high conductive filler content has insufficient welding strength when being welded with the electrode frame by laser welding, ultrasonic welding and other methods. Therefore, it is necessary to develop a carbon-plastic composite bipolar plate with high conductivity and low conductive filler content.
In order to pursue high power density, the flow battery requires low internal resistance of the battery, so that high requirements are imposed on the bulk conductivity of the bipolar plate and the contact resistance between the electrode and the bipolar plate. To increase the bulk conductivity, the content of the conductive filler is increased. In order to prepare the carbon-plastic composite bipolar plate material with the bulk conductivity higher than 5S/cm, the mass fraction of the conductive filler is usually more than 50%, and at the moment, because the polymer matrix contains a large amount of conductive filler, the welding strength is not high enough when the polymer matrix is welded with an electrode frame in a laser welding mode, an ultrasonic welding mode and the like, and the sealing effect cannot be realized. Therefore, to ensure high weld strength, a sufficiently high polymer content is ensured. However, such a bipolar plate material has poor electrical conductivity, especially because of containing more non-conductive polymer, the surface of the bipolar plate is composed of conductive particles and most of the non-conductive polymer, when the porous electrode is in contact with the bipolar plate, a part of contact points are in contact with the non-conductive polymer, and a conductive path cannot be formed, so that the contact resistance between the bipolar plate and the electrode material is large, the ohmic internal resistance of the battery is increased, and the battery performance is reduced.
Disclosure of Invention
The invention aims to provide a bipolar plate for a flow battery, which has high conductivity, high toughness, low conductive filler content, low contact resistance and high welding strength, and a preparation method thereof.
In order to achieve the purpose, the invention adopts the technical scheme that: the bipolar plate provided by the invention is shown in figure 1 and comprises a main body layer 1 which is a carbon-plastic composite plate consisting of high-density polyethylene, carbon nanotubes, a coupling agent and a lubricant, wherein high- conductivity coatings 2 and 3 are respectively arranged in the contact areas of the upper surface and the lower surface of the main body layer and the electrode.
The thickness of the main body layer is 0.2-1mm, in the main body layer, the mass fraction of the high-density polyethylene is 65-85%, the mass fraction of the carbon nano tube is 13-33%, the mass fraction of the coupling agent is 0.1-2%, and the mass fraction of the lubricating agent is 0.1-2%; preferably, the mass fraction of the high-density polyethylene is 71-83%, the mass fraction of the carbon nano tube is 15-25%, the mass fraction of the coupling agent is 1-2%, and the mass fraction of the lubricant is 1-2%;
the thickness of the high-conductivity coating on the upper surface and the lower surface is 1-1000 μm, preferably 1-100 μm, and the high-conductivity coating is composed of a mixture of carbon powder and a binder; the carbon powder is one or more than two of graphite powder, expanded graphite powder, carbon black, carbon fiber powder and graphene; the binder is one or two of polyvinylidene fluoride and polytetrafluoroethylene; the mass ratio of the carbon powder to the binder is 7/1-100/1, preferably 9/1-20/1.
Wherein the content of the first and second substances,
the high density polyethylene is an extrusion grade high density polyethylene and has a melt index of 0.05 to 10, preferably 0.05 to 2.
The carbon nanotube is a multi-walled carbon nanotube with a diameter of 10-100nm, a length of 5-100 μm, a mass purity of more than 95%, preferably 98-99.9%, and a specific surface area of 100-250m2/g。
The coupling agent is one or more than two of aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, vinyltriethoxysilane, mercaptopropyltrimethoxysilane (ethyl) oxysilane, ethylenediamine propyltriethoxysilane, ethylenediamine propylmethyldimethoxysilane, titanate, aluminate, zirconate and borate.
The lubricant is one or more than two of polyethylene wax, stearic acid, calcium stearate, zinc stearate, paraffin and vinyl bis stearamide.
The melt index is measured at 230 ℃/2.16kg using ASTM D1238 standard test method.
The method for preparing the bipolar plate comprises the following steps:
(1) uniformly mixing the high-density polyethylene, the carbon nano tube, the coupling agent and the lubricant according to the proportion required by the main layer by adopting an internal mixing mode, wherein the internal mixing temperature is 200-240 ℃, the rotor rotating speed is 40-60r/min, and the internal mixing time is 15-35 min;
(2) crushing the uniformly mixed banburying materials by using a crusher, adopting an extrusion calendaring molding process, and preparing a middle main body layer by using a single-screw extruder, wherein the temperature of a charging barrel is 160-250 ℃, and the temperature of a neck mold is 180-240 ℃;
(3) adding carbon powder and binder into ethanol and/or NMP solvent according to the proportion of high conductive coating, stirring and mixing uniformly, spreading a layer on the surface of electrode (such as carbon felt) placement region on one side surface of the main body layer by spraying or coating, drying to remove solvent, spreading a layer on the surface of carbon felt placement region on the other side of the middle main body layer, and drying at 30-80 deg.C to remove solvent;
(4) placing the carbon-plastic composite board with the high-conductivity coating evenly laid on the upper surface and the lower surface into a mould, and pressing the high-conductivity coating and the main body layer into a whole in a hot pressing mode to prepare the bipolar plate with low contact resistance; the hot pressing temperature is 100-300 ℃, the hot pressing pressure is 5-50 MPa, and the hot pressing time is 1-30 min.
The bipolar plate can be applied to all-vanadium flow batteries, zinc-bromine flow batteries, zinc-iron flow batteries, zinc-iodine flow batteries, sodium polysulfide-bromine flow batteries or zinc-nickel flow batteries.
The flow cell stack comprises an electrode frame, a bipolar plate and the electrode frame in the flow cell stack are not sealed by a sealing element, and the bipolar plate and the electrode frame are welded into a whole by an ultrasonic welding or laser welding method and are simultaneously sealed.
Compared with the prior art, the invention has the following advantages:
(1) compared with the existing carbon-plastic composite bipolar plate, the bipolar plate provided by the invention has the advantages that the carbon nano tube content is lower, the toughness and the mechanical strength are higher, and the galvanic pile assembly is easy.
(2) Compared with the existing carbon-plastic composite bipolar plate, the bipolar plate provided by the invention has the advantages that the polymer content in the contact area with the electrode frame is higher, so that the high enough welding strength can be ensured during welding with the electrode frame, and the reliability of a galvanic pile can be ensured.
(3) Compared with the existing carbon-plastic composite bipolar plate, the bipolar plate has the advantages that the contact points between the bipolar plate and the porous electrode are all conductive points due to the high-conductivity coating layer on the contact surface of the bipolar plate and the electrode material, so that a better conductive network can be constructed by utilizing the conductive points on the surfaces of the bipolar plate and the porous electrode to the greatest extent, the contact resistance between the electrode bipolar plate is reduced, and the voltage efficiency of a battery is improved.
(4) Compared with the existing carbon-plastic composite bipolar plate taking polypropylene as a matrix, the bipolar plate has higher corrosion resistance due to the fact that the polymer matrix is made of high-density polyethylene, and can be used for a long time in all-vanadium flow batteries, other halogen-containing flow batteries and other flow batteries, such as zinc-bromine flow batteries, vanadium-bromine flow batteries, sodium polysulfide-bromine flow batteries and alkaline electrolyte flow batteries, of which electrolyte is made of mixed acid of sulfuric acid and hydrochloric acid.
(5) The bipolar plate provided by the invention has the advantages of simple preparation method, easily controlled production process, easy batch preparation, low price of used raw materials and capability of realizing localization of all the raw materials.
Drawings
FIG. 1 is a schematic view of the structure of a bipolar plate according to the present invention; 1-a main body layer, 2, 3-a high conductive coating in the contact area of the middle part of the main body layer and the upper and lower surface electrodes respectively;
fig. 2 is a graph showing the voltage efficiencies of the single cell in example 1 of the present invention and the single cell in the comparative example at different current densities.
Detailed Description
The present invention is described in detail below with reference to specific examples.
Example 1
Respectively weighing 0.78kg of high-density polyethylene (melt index of 0.5), 0.2kg of carbon nano tube, 10g of titanate coupling agent, 5g of polyethylene wax and 5g of zinc stearate, wherein the diameter of the carbon nano tube is 20-30nm, the length of the carbon nano tube is 15-50 mu m, the purity of the carbon nano tube is 99 percent, and the specific surface area of the carbon nano tube is 160m2(ii) in terms of/g. The materials are mixed and then added into an internal mixer, the internal mixing temperature is 200 ℃, the rotor speed is 40r/min, and the internal mixing time is 20 minutes. And then crushing the uniformly mixed internal mixing material by a crusher, feeding the crushed material into a single-screw extruder, extruding a sheet at the charging barrel temperature of the extruder of 200 ℃, the main machine rotating speed of 15rpm and the mouth mold temperature of 230 ℃, and performing calendaring molding to obtain the carbon-plastic composite bipolar plate with the thickness of 0.8 mm.
Weighing 90g of nano graphite powder and 10g of PVDF, adding into 1L of ethanol, stirring and mixing uniformly, blade-coating the nano graphite powder and 10g of PVDF on the surface of a carbon-plastic composite plate by using a 100-micrometer scraper, and drying to remove ethanol; then the obtained product is placed into a mould for hot-press forming. The hot pressing temperature is 200 ℃, the hot pressing pressure is 20MPa, and the hot pressing time is 5 min.
The contact resistances of the bipolar plates of the present example and the comparative example with the carbon felt were measured, respectively, and the results showed that the contact resistance of the bipolar plates of the present example was from 100 m.OMEGA.cm with respect to the comparative example2Reduced to 35m omega cm2And the reduction is 65 percent.
The bipolar plate of the embodiment is used for assembling the all-vanadium redox flow battery, and the positive electrolyte is 1.5M VO2+3M H2SO440ml of the solution, the negative electrode electrolyte solution was 1.5M V3+3M H2SO440ml of the solution. The voltage efficiencies of the cells at different current densities are shown in fig. 2. The single cell adopting the bipolar plate has the current density of 80mA/cm2When the voltage efficiency reaches 92.8 percent; the current density is 160mA/cm2The voltage efficiency still reaches 85.2%, which is much higher than that of the bipolar plate without the high conductive coating in the comparative example.
Example 2
Respectively weighing 0.83kg of high-density polyethylene (melt index of 0.05), 0.15kg of carbon nano tube, 10g of aminopropyltriethoxysilane coupling agent, 5g of polyethylene wax and 5g of zinc stearate, wherein the diameter of the carbon nano tube is 15-30nm, the length of the carbon nano tube is 15-30 mu m, the purity of the carbon nano tube is 99 percent, and the specific surface area of the carbon nano tube is 200m2(ii) in terms of/g. The materials are mixed and then added into an internal mixer, the internal mixing temperature is 200 ℃, the rotor speed is 45r/min, and the internal mixing time is 20 minutes. And then crushing the uniformly mixed internal mixing material by a crusher, feeding the crushed material into a single-screw extruder, extruding a sheet at the charging barrel temperature of the extruder of 200 ℃, the main machine rotating speed of 15rpm and the mouth mold temperature of 230 ℃, and performing calendaring molding to obtain the carbon-plastic composite bipolar plate with the thickness of 1 mm.
Weighing 88g of carbon fiber powder and 12g of PVDF, adding the carbon fiber powder and 12g of PVDF into 1L NMP, stirring and mixing uniformly, blade-coating the carbon fiber powder and 12g of PVDF on the surface of a carbon-plastic composite plate by using a 100-micrometer scraper, and then drying to remove NMP; then the obtained product is placed into a mould for hot-press forming. The hot pressing temperature is 200 ℃, the hot pressing pressure is 20MPa, and the hot pressing time is 5 min.
Example 3
0.8kg of high-density polyethylene (melt index of 1) is weighed respectively,0.18kg of carbon nano tube, 10g of aluminate coupling agent and 10g of calcium stearate, wherein the diameter of the carbon nano tube is 20-30nm, the length of the carbon nano tube is 15-50 mu m, the purity of the carbon nano tube is 99 percent, and the specific surface area of the carbon nano tube is 160m2(ii) in terms of/g. The materials are mixed and then added into an internal mixer, the internal mixing temperature is 220 ℃, the rotor speed is 50r/min, and the internal mixing time is 20 minutes. And then crushing the uniformly mixed internal mixing material by a crusher, feeding the crushed material into a single-screw extruder, extruding a sheet at the temperature of a charging barrel of the extruder of 230 ℃, the rotating speed of a main engine of 8rpm and the temperature of a neck ring of 200 ℃, and performing calendaring molding to obtain the carbon-plastic composite bipolar plate with the thickness of 0.5 mm.
Weighing 95g of graphite powder and 5g of PVDF, adding the graphite powder and the PVDF into 1L NMP, stirring and mixing uniformly, blade-coating the graphite powder and the PVDF on the surface of a carbon-plastic composite plate by using a 150-micrometer scraper, and then drying to remove NMP; then the obtained product is placed into a mould for hot-press forming. The hot pressing temperature is 200 ℃, the hot pressing pressure is 20MPa, and the hot pressing time is 5 min.
Example 4
Respectively weighing 0.73kg of high-density polyethylene (melt index of 2), 0.25kg of carbon nano tube, 10g of titanate coupling agent, 5g of polyethylene wax and 5g of zinc stearate, wherein the diameter of the carbon nano tube is 20-30nm, the length of the carbon nano tube is 15-50 mu m, the purity of the carbon nano tube is 99 percent, and the specific surface area of the carbon nano tube is 160m2(ii) in terms of/g. The materials are mixed and then added into an internal mixer, the internal mixing temperature is 220 ℃, the rotor speed is 50r/min, and the internal mixing time is 20 minutes. And then crushing the uniformly mixed internal mixing material by a crusher, feeding the crushed material into a single-screw extruder, extruding a sheet at the temperature of a charging barrel of the extruder of 230 ℃, the rotating speed of a main engine of 8rpm and the temperature of a neck ring of 200 ℃, and performing calendaring molding to obtain the carbon-plastic composite bipolar plate with the thickness of 0.5 mm.
Weighing 90g of graphene and 10g of PVDF, adding the graphene and the PVDF into 5L NMP, stirring and mixing uniformly, blade-coating the graphene and the PVDF on the surface of a carbon-plastic composite plate by using a 100-micrometer scraper, and then drying to remove NMP; then the obtained product is placed into a mould for hot-press forming. The hot pressing temperature is 200 ℃, the hot pressing pressure is 20MPa, and the hot pressing time is 5 min.
Comparative example
0.78kg of high-density polyethylene (melt index of 0.05), 0.2kg of carbon nano-tube, 10g of titanate coupling agent, 5g of polyethylene wax and 5g of zinc stearate are respectively weighed, wherein the diameter of the carbon nano-tube is 20-30nm, length of 15-50 μm, purity of 99%, and specific surface area of 160m2(ii) in terms of/g. The materials are mixed and then added into an internal mixer, the internal mixing temperature is 200 ℃, the rotor speed is 40r/min, and the internal mixing time is 20 minutes. And then crushing the uniformly mixed internal mixing material by a crusher, feeding the crushed material into a single-screw extruder, extruding a sheet at the charging barrel temperature of the extruder of 200 ℃, the main machine rotating speed of 15rpm and the mouth mold temperature of 230 ℃, and performing calendaring molding to obtain the carbon-plastic composite bipolar plate with the thickness of 0.8 mm.
The conductivity, the contact resistance with the carbon felt electrode, the mechanical properties and the welding strength of the carbon-plastic composite plate in the bipolar plate and the comparative example were respectively tested, and the results are shown in table 1. Therefore, compared with the prior art, the bipolar plate has higher conductivity.
TABLE 1
Figure BDA0001886770610000051

Claims (9)

1. A weldable bipolar plate for a flow battery, comprising: the bipolar plate comprises a main body layer, wherein the main body layer is a carbon-plastic composite plate consisting of high-density polyethylene, carbon nano tubes, a coupling agent and a lubricant, and high-conductivity coatings are respectively arranged in the middle parts of the upper surface and the lower surface of the main body layer and are used for contacting with electrode contact areas;
the thickness of the main body layer is 0.2-1mm, in the main body layer, the mass fraction of the high-density polyethylene is 65-85%, the mass fraction of the carbon nano tube is 13-33%, the mass fraction of the coupling agent is 0.1-2%, and the mass fraction of the lubricating agent is 0.1-2%; preferably, the mass fraction of the high-density polyethylene is 71-83%, the mass fraction of the carbon nano tube is 15-25%, the mass fraction of the coupling agent is 1-2%, and the mass fraction of the lubricant is 1-2%;
the thickness of the high-conductivity coating on the upper surface and the lower surface is 1-1000 μm, preferably 1-100 μm, and the high-conductivity coating is composed of a mixture of carbon powder and a binder; the carbon powder is one or more than two of graphite powder, expanded graphite powder, carbon black, carbon fiber powder and graphene; the binder is one or two of polyvinylidene fluoride and polytetrafluoroethylene; the mass ratio of the carbon powder to the binder is 7/1-100/1, preferably 9/1-20/1.
2. The bipolar plate of claim 1, wherein: the high density polyethylene is an extrusion grade high density polyethylene and has a melt index of 0.05 to 10, preferably 0.05 to 2.
3. The bipolar plate of claim 1, wherein: the carbon nanotube is a multi-walled carbon nanotube with a diameter of 10-100nm, a length of 5-100 μm, a mass purity of more than 95%, preferably 98-99.9%, and a specific surface area of 100-250m2/g。
4. The bipolar plate of claim 1, wherein: the coupling agent is one or more than two of aminopropyltriethoxysilane, glycidoxypropyltrimethoxysilane, vinyltriethoxysilane, mercaptopropyltrimethoxysilane (ethyl) oxysilane, ethylenediamine propyltriethoxysilane, ethylenediamine propylmethyldimethoxysilane, titanate, aluminate, zirconate and borate.
5. The bipolar plate of claim 1, wherein: the lubricant is one or more than two of polyethylene wax, stearic acid, calcium stearate, zinc stearate, paraffin and vinyl bis stearamide.
6. A bipolar plate as set forth in claim 2, wherein: the melt index is measured at 230 ℃/2.16kg using ASTM D1238 standard test method.
7. A method of manufacturing a bipolar plate as claimed in any one of claims 1 to 6, wherein: the preparation method of the bipolar plate comprises the following steps:
(1) uniformly mixing the high-density polyethylene, the carbon nano tube, the coupling agent and the lubricant according to the proportion required by the main layer by adopting an internal mixing mode, wherein the internal mixing temperature is 200-240 ℃, the rotor rotating speed is 40-60r/min, and the internal mixing time is 15-35 min;
(2) crushing the uniformly mixed banburying materials by using a crusher, adopting an extrusion calendaring molding process, and preparing a middle main body layer by using a single-screw extruder, wherein the temperature of a charging barrel is 160-250 ℃, and the temperature of a neck mold is 180-240 ℃;
(3) adding carbon powder and a binder into ethanol and/or NMP solvent according to a ratio required by the high-conductivity coating, stirring and mixing uniformly, respectively coating the mixture on contact areas of the middle part of the main body layer and the upper and lower surface electrodes, drying at 30-80 ℃ to remove the solvent, and forming the high-conductivity coating on the contact areas of the middle part of the main body layer and the upper and lower surface electrodes;
(4) putting the bipolar plate with the high-conductivity coating evenly laid on the upper surface and the lower surface into a mould, and pressing the high-conductivity coating and the main body layer into a whole in a hot pressing mode to prepare the weldable bipolar plate; the hot pressing temperature is 100-300 ℃, the hot pressing pressure is 5-50 MPa, and the hot pressing time is 1-30 min.
8. Use of a bipolar plate according to any one of claims 1 to 6, wherein: the bipolar plate is applied to flow batteries including all-vanadium flow batteries, zinc-bromine flow batteries, zinc-iron flow batteries, zinc-iodine flow batteries, vanadium-bromine flow batteries, sodium polysulfide-bromine flow batteries or zinc-nickel flow batteries; the electrolyte is preferably applied to an all-vanadium flow battery, a zinc-bromine flow battery, a vanadium-bromine flow battery, a sodium polysulfide-bromine flow battery or a zinc-nickel battery for use; more preferably, the electrolyte is an all vanadium flow battery using a mixed acid of sulfuric acid and hydrochloric acid as a supporting electrolyte, or an alkaline zinc-iron flow battery.
9. Use of a bipolar plate according to claim 8, wherein: the flow cell stack comprises an electrode frame, a bipolar plate and the electrode frame in the flow cell stack are not sealed by a sealing element, and the bipolar plate and the electrode frame are welded into a whole by an ultrasonic welding or laser welding method and are simultaneously sealed.
CN201811451354.2A 2018-11-30 2018-11-30 Weldable bipolar plate for flow battery and preparation and application thereof Pending CN111261891A (en)

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CN111933963A (en) * 2020-09-11 2020-11-13 杭州德海艾科能源科技有限公司 Vanadium cell concatenation graphite bipolar plate
CN112909280A (en) * 2020-12-31 2021-06-04 大连融科储能技术发展有限公司 Method for insulating surface edge of bipolar plate and application thereof
CN114520345A (en) * 2020-11-20 2022-05-20 中国科学院大连化学物理研究所 Integrated electrode frame with bipolar plate and preparation and application thereof
CN115548363A (en) * 2022-11-29 2022-12-30 山东海化集团有限公司 Weldable bipolar plate for flow battery and preparation method and application thereof

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CN111933963A (en) * 2020-09-11 2020-11-13 杭州德海艾科能源科技有限公司 Vanadium cell concatenation graphite bipolar plate
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CN115548363A (en) * 2022-11-29 2022-12-30 山东海化集团有限公司 Weldable bipolar plate for flow battery and preparation method and application thereof

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