The dual polar plates of proton exchange membrane fuel cell that mechanical property, conduction and thermal conductivity are good
The application is application number: the divisional application of 201110145554.7, the applying date: 2011-06-01, title " Composite Bipolar Plates For Polymer Electrolyte Membrane Fuel Cell and production method ".
Technical field
The present invention relates to a kind of advanced composite material (ACM) bipolar plates formula and the manufacturing process of Proton Exchange Membrane Fuel Cells.
Background technology
21st century is century of energy scarcity, the exploitation of novel energy, the reasonable efficiency utilization of the existing energy has been become to the theme of development in this century.At present, the fossil energies such as the oil that the mankind depend on for existence, natural gas and coal are reducing increasingly, instead will be the renewable resources such as Hydrogen Energy, solar energy and wind energy.Meanwhile, owing to using the inefficient combustion of existing resource (as oil, natural gas and coal), both wasted the energy, also severe contamination was caused to environment, become the major issue that must solve this century.
Fuel cell (FuelCells) is a kind of electricity can be directly the Blast Furnace Top Gas Recovery Turbine Unit (TRT) of electric energy by chemical energy.Energy conversion efficiency high (40%-60%); Environmental friendliness, discharges nitrogen oxide and oxysulfide hardly; The discharge capacity of carbon dioxide also reduces more than 50% than conventional power plant.Just because of the superiority that these are outstanding, the research and development of fuel cell technology enjoys the attention of national governments and major company of the world, is considered to the cleaning of 21 century first-selection, efficiently generation technology, becomes everybody and research and develop focus.
Hydrogen-oxygen proton exchange membrane fuel cell (ProtonExchangeMembraneFuelCell, PEMFC) use hydrogen fuel, air or oxygen are oxidant, except there is the general feature of fuel cell (as high in energy conversion efficiency, environmental friendliness etc.), also have simultaneously can start (working temperature is generally at 60 ~ 100 DEG C) in room temperature fast, easily discharge without electrolyte loss, water, the outstanding feature such as the life-span is long, specific power and energy height, particularly its emission is water, achieves pollution-free zero discharge.Therefore, it is acknowledged as the first-selected power supply promising to be military affairs, space flight, navigation, electric automobile and regional power station most.
Bipolar plates is the critical piece of Proton Exchange Membrane Fuel Cells (PEMFC), and bipolar plates profile is generally plate, and single or double has the flow field (groove) of dark 1mm, wide about 1mm, is the passage for hydrogen and oxygen flowing.The major function of bipolar plates has: the fuel in (1) distribution battery and oxidant; (2) monocell in split cell group; (3) conduction current; (4) transmission generates water, moisture; (5) cool batteries group.The expense of bipolar plates accounts for the over half of fuel cell, seriously hinders the commercialization of Proton Exchange Membrane Fuel Cells, finds cheap, and the life-span bipolar plate material of length becomes the extremely urgent problem of Proton Exchange Membrane Fuel Cells commercialization.
At present, the main material and the method that manufacture bipolar plates have:
(1) pure graphite bi-polar plate
The coke of general employing graphite powder, pulverizing mixes with graphitisable resin or pitch, strict with certain heating schedule in graphitizing furnace, be warming up to 2500 ~ 2700 DEG C, preparation atresia or low porosity (being not more than 1%), only containing the graphite block of nano grade pore, again through cutting and grinding, prepare the graphite cake that thickness is 2 ~ 5mm, machine work shares duct and carves the flow field of painting needs with computer engraving machine on its surface.The preparation technology of this graphite bi-polar plate is not only complicated, consuming time, costly, and is difficult to realize batch production.Graphite material has superior electric conductivity, thermal conductivity and anti-wear performance, and be a kind of low density material, be the preferred material of bipolar plates always, and the high temperature graphitization in process for machining and the machine work of gas flow cause the expensive main cause of bipolar plates.
(2) metal double polar plates
Metal material bipolar plates has the advantages such as the good and gas permeation rate of high conductivity, high-termal conductivity, mechanical strength is low, but metal is under the environment of fuel cell operation, and easily corrosion can not meet the requirement of Long-Time Service.Making the outstanding advantage of bipolar plate material with metal sheet is be particularly suitable for batch production, as the bipolar plates adopting stamping technology to prepare various configuration.The matter of utmost importance adopting metal sheet to prepare bipolar plates solves it at PEMFC condition of work (oxidation, reducing atmosphere, certain current potential and faintly acid electrolyte) under stability (i.e. anticorrosive problem), another problem is exactly also need to investigate its life-span further.
(3) graphite/polymer
For reducing the preparation cost of graphite bi-polar plate, meeting the requirement used in enormous quantities, preparing composite material double pole plate by graphite powder and fluoropolymer resin and other various formula and similar approach.This method, owing to adopting compression molding, so runner can directly go out in one-shot forming, has the advantages that efficiency is high, cost is low, has become one of current PEMFC bipolar plates research direction with development prospect, abroad existing large-scale production.But there is the deficiencies such as conductivity is low, intensity is low, thermal conductivity is low in the bipolar plates that this method is produced and the bipolar plates ratio that above-mentioned two kinds of methods are produced.
Summary of the invention
For the aspect requirement of bipolar plates mechanical property, mainly fitting tight and fastening time, certain resistance to compression and bending strength must be had, impact, alternate load complicated applied force situation is not had during work, so meeting under certain mechanics performance condition, mainly improving its conduction, heat conductivility and corrosion resistance.The object of the present invention is to provide Composite Bipolar Plates For Polymer Electrolyte Membrane Fuel Cell and production method that a kind of mechanical property, conduction and thermal conductivity are good.
It is of the present invention that to be exactly solution be:
A kind of Composite Bipolar Plates For Polymer Electrolyte Membrane Fuel Cell, is characterized in that: be made up of the raw material of following weight percents:
Described curing agent is hexamethylenetetramine.
A production method for Composite Bipolar Plates For Polymer Electrolyte Membrane Fuel Cell, is characterized in that: comprise the steps:
1) titanium carbide of the phenolic resins of 5% ~ 20% percentage by weight, 1% ~ 10% percentage by weight and the graphite of 60% ~ 93% percentage by weight are mixed, then put into 60 ~ 100 DEG C of baking ovens oven dry 1 ~ 5h;
2) taken out by dried powder, add curing agent, put into mold cavity, mold cavity is processed with runner (flow field), and making can all one-shot forming by runner after mold pressing; Matched moulds: carry out matched moulds after reinforced, burn close time is 5s ~ 30s, and the pressure of matched moulds is at 5 ~ 60MPa, and compression molding temperature is 130 ~ 220 DEG C, and temperature retention time is 1 ~ 15min.; Exhaust: need release to be vented after mould matched moulds, the number of times of exhaust is 1 ~ 3 time, and each time is 3s ~ 20s; The demoulding: after having solidified, uses the push rod demoulding.
3) after compression molding, clamp bipolar plates with fixture and put into baking oven, isothermal holding, make bipolar plates solidify to obtain finished product further.Annealing temperature is 80 ~ 130 DEG C, and temperature retention time is 4 ~ 24h.
Step 1) described in hybrid mode be that ball milling is dry mixed or thinks alcohol solvent wet mixing.
The present invention selects graphite powder, phenol-formaldehyde resin modified and titanium carbide powder.Titanium carbide (TiC) belongs to face-centered cubic crystal formation, fusing point is high, good heat conductivity, hardness is large, and chemically stable is good, and high-temperature oxidation resistance is good, do not react with acid at normal temperatures, have very strong decay resistance and very high conductivity (also higher than pure graphite), greatly can improve the mechanical property of PF Resin/Graphite Composite bipolar plates, conduction and thermal conductivity, obtained bipolar plates not only has higher conductivity, thermal conductivity, higher intensity and resistance to hydrogen-type corrosion.
The performance of the bipolar plates that the present invention obtains can reach:
Conductivity 210S/cm, bending strength 36MPa, compression strength 105MPa.
Accompanying drawing explanation
Below in conjunction with drawings and Examples, the invention will be further described.
Fig. 1 is the production method flow chart of one embodiment of the invention.
Embodiment
Embodiment 1:
1) titanium carbide of the phenolic resins of 10% percentage by weight, 10% percentage by weight and the graphite of 77% percentage by weight are carried out ball milling to be dry mixed, then put into 60 ~ 100 DEG C of baking ovens oven dry 1 ~ 5h;
2) taken out by dried powder, add the curing agent hexamethylenetetramine of 3% percentage by weight, put into mold cavity, mold cavity is processed with runner (flow field), and making can all one-shot forming by runner after mold pressing; Matched moulds: carry out matched moulds after reinforced, burn close time is 5s ~ 30s, and the pressure of matched moulds is at 40MPa, and compression molding temperature is 200 DEG C, and temperature retention time is 5min.; Exhaust: need release to be vented after mould matched moulds, the number of times of exhaust is 1 ~ 3 time, and each time is 3s ~ 20s; The demoulding: after having solidified, uses the push rod demoulding.
3) after compression molding, clamp bipolar plates with fixture and put into baking oven, isothermal holding, make bipolar plates solidify to obtain finished product further.Annealing temperature is 80 ~ 130 DEG C, and temperature retention time is 4 ~ 24h.
The performance of obtained bipolar plates is as follows:
Conductivity 210S/cm, bending strength 36Mpa, compression strength 105Mpa.
Embodiment 2:
1) graphite of titanium carbide and 60% ~ 93% (example 60%, 75%, the 93%) percentage by weight of the phenolic resins of 5% ~ 20% (example 5%, 12%, 20%) percentage by weight, 1% ~ 10% (example 1%, 5%, 10%) percentage by weight is mixed, then put into 60 ~ 100 DEG C of (example 60 DEG C, 80 DEG C, 100 DEG C) baking ovens and dry 1 ~ 5h;
2) dried powder is taken out, add the curing agent of 1 ~ 10% (example 1%, 6%, 10%) percentage by weight, put into mold cavity, mold cavity is processed with runner (flow field), and making can all one-shot forming by runner after mold pressing; Matched moulds: carry out matched moulds after reinforced, burn close time is 5s ~ 30s, the pressure of matched moulds at 5 ~ 60MPa (routine 5MPa, 30MPa, 60MPa), compression molding temperature be 130 ~ 220 DEG C (example 130 DEG C, 180 DEG C, 220 DEG C), temperature retention time is 1 ~ 15min.; Exhaust: need release to be vented after mould matched moulds, the number of times of exhaust is 1 ~ 3 time, and each time is 3s ~ 20s; The demoulding: after having solidified, uses the push rod demoulding.
3) after compression molding, clamp bipolar plates with fixture and put into baking oven, isothermal holding, make bipolar plates solidify to obtain finished product further.Annealing temperature be 80 ~ 130 DEG C (example 80 DEG C, 100 DEG C, 130 DEG C), temperature retention time is 4 ~ 24h.
Step 1) described in hybrid mode be that ball milling is dry mixed or thinks alcohol solvent wet mixing.