CN1996648A - Method for manufacturing membrane electrode assembly for fuel cell - Google Patents

Method for manufacturing membrane electrode assembly for fuel cell Download PDF

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Publication number
CN1996648A
CN1996648A CNA2006101542328A CN200610154232A CN1996648A CN 1996648 A CN1996648 A CN 1996648A CN A2006101542328 A CNA2006101542328 A CN A2006101542328A CN 200610154232 A CN200610154232 A CN 200610154232A CN 1996648 A CN1996648 A CN 1996648A
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China
Prior art keywords
catalyst layer
coating
catalyst
polyelectrolyte
layer
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CNA2006101542328A
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Chinese (zh)
Inventor
泉伸太郎
上木原伸幸
渡边胜
尾崎祐介
小林美穗
上山康博
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Panasonic Holdings Corp
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Matsushita Electric Industrial Co Ltd
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Publication of CN1996648A publication Critical patent/CN1996648A/en
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    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/30—Hydrogen technology
    • Y02E60/50—Fuel cells
    • 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
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/50—Manufacturing or production processes characterised by the final manufactured product

Abstract

A method for manufacturing a membrane electrode assembly for a fuel cell, which greatly improves the productivity and performance of the fuel cell. The method comprises a first catalyst layer forming step wherein a first catalyst layer (201) is formed by applying a noble metal-loaded first coating compound on a moving base (9), an electrolyte forming step wherein an electrolyte layer (301) is formed by applying a second coating compound, which contains a hydrogen ion-conductive resin, on the first catalyst layer (201) while the layer (201) is wet, a drying step wherein the electrolyte layer (301) is dried, and a second catalyst layer forming step wherein a second catalyst layer (401) is formed by applying a noble metal-loaded third coating compound on the dried electrolyte layer (301).

Description

The manufacture method of fuel battery membrane electrode assembly
The application is that application number is 03822987.0, the applying date is dividing an application of March 25, denomination of invention in 2005 manufacture method that is fuel battery membrane electrode assembly.
Technical field
The present invention relates to make manufacture method, its manufacturing installation, membrane-electrode assembly, fuel cell the polyelectrolyte coating and the polymer electrolyte fuel cells of the fuel battery membrane electrode assembly of employed fuel battery membrane electrode assembly in the polymer electrolyte fuel cell.
Background technology
Fuel cell is to make the fuel gas that contains hydrogen and contain the oxidant gas generation electrochemical reaction of aerobic etc. and produce the object of electric energy.In fuel cell, phosphoric acid type fuel cell, fused carbonate type fuel cell, oxide fuel cell and polymer electrolyte fuel cells etc. are for example arranged.
Polymer electrolyte fuel cells (PEFC) just can produce electric energy and heat simultaneously by making the fuel gas that contains hydrogen, air etc., containing the oxidant gas generation electrochemical reaction of aerobic.Also fuel gas and oxidant gas merging are called reacting gas.
PEFC is the fuel cell that electrolyte is used as polyelectrolyte membrane, and described polyelectrolyte membrane optionally conducts hydrogen ion.In addition, PEFC possesses and comprises that folder is every described polyelectrolyte membrane and the conjugant of the structure of stacked pair of electrodes.This kind comprised that the conjugant of polyelectrolyte membrane and pair of electrodes is called membrane-electrode assembly (MEA).In the described electrode in MEA, contain and be useful on the catalyst layer that makes the catalyst that electrochemical reaction carries out.Described catalyst layer is as long as contact with polyelectrolyte membrane.
Now, be extensive use of the porous electrode that comprises catalyst layer and gas diffusion layers as electrode.In the described catalyst layer, mainly use with the carbon dust that supported noble metal catalyst as principal component.In addition, in the described gas diffusion layers, the main use has conductivity and with respect to the carbon paper of the aeration of gas etc.
In the actual battery,, dispose the barrier film that is provided with gas flow path with conductivity on the two sides of described MEA.Described barrier film is undertaken reacting gas is supplied with to MEA, the effect that generation gas that will generate because of cell reaction or remaining reacting gas are transported.This kind is called single cell units by the tectosome that MEA and a pair of barrier film constitute.
When a plurality of single cell units that will obtain as mentioned above are stacked, just can obtain to export accordingly the laminated cell of voltage from three ten-day period of hot season spy to hundreds of volts with stacked number.This kind laminated cell is called fuel cell stack (perhaps being commonly referred to as fuel cell).
In the fuel electrodes of MEA (anode) and the oxidizing agent pole (negative electrode), produce the reaction of representing with following reaction equation respectively.
Anode: H 2→ 2H ++ 2e -
Negative electrode: 1/2O 2+ 2H ++ 2e -→ H 2O
The electronics that produces in the anode moves to negative electrode through external circuit.Meanwhile, the hydrogen ion that produces in the anode passes polyelectrolyte membrane and moves to negative electrode, generates electricity.
The membrane-electrode assembly that constitutes polymer electrolyte fuel cells is made of dielectric substrate, the catalyst layer that is in the table back side of this dielectric substrate as mentioned above, and a side of catalyst layer is called the hydrogen utmost point, and the opposing party is called the oxygen utmost point.
By supply with hydrogen to the hydrogen utmost point, supply with oxygen to the oxygen utmost point, hydrogen just becomes hydrogen ion because of the catalyst of the hydrogen utmost point, moves in dielectric substrate, and the catalytic reaction of utilizing the oxygen utmost point is reacted with oxygen and is become water.Electronics is moving to the hydrogen Ghandler motion from the oxygen utmost point in this process.
This kind membrane-electrode assembly is made by following.
That is the manufacture method of expression membrane-electrode assembly in the past among Figure 10～Figure 13.Below this manufacture method is called mode of printing in the past.
At first, in the mode of printing in the past, as shown in figure 10, by with extrusion shaper with fusion polyelectrolyte 15 on base material 9a, be coated with and become band, will be by base material 9a and be formed at the thin slice extrusion molding of the polyelectrolyte that the polyelectrolyte 15 on the base material 9a constitutes.
Then, as shown in figure 11, will be by base material 9b and the thin slice that is formed at first catalyst layer that first catalyst layer 201 (the hydrogen utmost point) on the base material 9b constitutes cut out cut and be essential shape.And the thin slice of this first catalyst layer is a thin slice of using the manufacturing process identical with extrusion molding illustrated in fig. 10 to be shaped.And first catalyst layer 201 is the layers that play a role as the hydrogen utmost point.
Then, as shown in figure 12, the thin slice heat that will cut out first catalyst layer that cuts in the operation of Figure 11 is transferred on the thin slice of the polyelectrolyte that is shaped in the operation of Figure 10.That is, on the polyelectrolyte 301 that is formed on the base material 9a, the thin slice of first catalyst layer that has utilized pushing of hot transfer platen and heating to cut out to cut.That is, first catalyst layer 201 is pressed against on the polyelectrolyte layers 301 by hot transfer platen and is heated.By utilizing hot transfer platen 18 heating and pushing like this, just first catalyst layer, 201 heat are transferred on the polyelectrolyte layers 301.
At last, as shown in figure 13, with among Figure 12 by hot transfer printing polyelectrolyte layers 301 and the counter-rotating of first catalyst layer 201, the base material 9a of the thin slice of polyelectrolyte is removed.After this, the configuration printing with the coating of filling second catalyst layer, 401 usefulness in the mould 19, is removed by scanning printing the coating of surplus in printing with mould 19 with cutter head 20 on polyelectrolyte layers 301.Like this, promptly utilize printing to form second catalyst layer 401.And second catalyst layer 401 is the layers that play a role as the oxygen utmost point.And the coating of second catalyst layer 401 is to use the carbon dust that will support noble metal on the particulate of carbon black as caltalyst, has mixed the material of resin glue and solvent in described caltalyst.
Like this, by through the described Figure 10 that associates to the operation of Figure 13, make the membrane-electrode assembly that constitutes by first catalyst layer 201, polyelectrolyte layers 301 and second catalyst layer 401.
And, in the described mode of printing, adopt after the thin slice heat with first catalyst layer is transferred on the thin slice of polyelectrolyte printing second catalyst layer 401 on the thin slice of polyelectrolyte and the explanation carried out.Promptly, utilize transfer printing to form first catalyst layer 201 though adopt, utilize and print the explanation that forms second catalyst layer 401 and carry out, be not limited thereto, both can all utilize transfer printing to form first catalyst layer 201 and second catalyst layer 401, and also can all utilize printing to form in addition.In addition, the order that forms first catalyst layer 201 and second catalyst layer 401 with which for earlier can, also can utilize any one method of transfer printing and printing to form respectively first catalyst layer 201 and second catalyst layer 401 this moment.
Below, describe with reference to the manufacture method of Figure 14 pair of membrane-electrode assembly different with described mode of printing.And, below this manufacture method is called cylinder mode in the past.Among Figure 14,1 is nozzle, and 5 is paint feeding device, and 9 is base material, and 10 is cylinder, and 11 is the coating that first catalyst layer is used.In addition, paint feeding device 5 is made of jar 501 and pump 502.The coating 11 of first catalyst layer uses the carbon dust that will support noble metal on the particulate of carbon black to be caltalyst, has mixed the material of resin glue and solvent in described caltalyst.
Below, the action of in the past cylinder mode is described.
The coating 11 that storage has the 1st catalyst layer to use in jar 501.The 1st catalyst layer, is coated on the base material 9 of the ring-type that cylinder 10 moves from nozzle 1 via pump 502 with coating 11 with becoming band continuously.And, also the 1st catalyst layer can be coated on the base material 9 off and on coating 11.Being coated with first catalyst layer is like this temporarily wound up after drying with the base material 9 of coating 11.Like this just form first catalyst layer on the base material 9.
Then, in the formation of the base material 9 of having been reeled on the face of the 1st catalyst layer, utilize the operation identical with Figure 14, be coated with the coating that dielectric substrate is used bandedly.After this, the base material 9 that has been coated with the coating that dielectric substrate uses is temporarily wound up after drying.Like this just on base material 9, form these 2 layers of first catalyst layer and dielectric substrates.
Then, in the formation of the base material 9 of having been reeled on the face of dielectric substrate, utilize the operation identical with Figure 14, be coated with the coating that second catalyst layer is used bandedly.After this, the base material 9 that has been coated with the coating that second catalyst layer uses is temporarily wound up after drying.Like this just on base material 9, form these 3 layers of first catalyst layer, dielectric substrate and second catalyst layers.
At last, cut out to cut and be specific shape, just obtain membrane-electrode assembly by being formed at the 1st catalyst layer on the base material 9, dielectric substrate and second catalyst layer.
And, though use nozzle 1 to make membrane-electrode assembly among Figure 14, also can replace nozzle 1, as shown in figure 15, use the plate 21 at the end that forms fluid storage compartment and the cutter head 22 of the thickness that adjustment is filmed.And, identical owing to the method for Figure 15 is used plate 21, the cutter head 22 except replacing nozzle 1 with the manufacture method of Figure 14, so omission will be described.
In addition, when use membrane-electrode assembly in the past generates electricity, compare with second catalyst layer (the oxygen utmost point), first catalyst layer (the hydrogen utmost point) side produces more reaction.So under first catalyst layer (the hydrogen utmost point) situation identical with the amount of catalyst in second catalyst layer (the oxygen utmost point), the hydrogen ion that produces in first catalyst layer (the hydrogen utmost point) will be superfluous, efficient is poor.Thus, will make second catalyst layer (the oxygen utmost point) compare the work that contains the noble metals such as platinum that more become catalyst, or make the thickness of second catalyst layer (the oxygen utmost point) compare thicker work with first catalyst layer (the hydrogen utmost point) with first catalyst layer (the hydrogen utmost point).
In addition, as with the manufacture method of described different membrane-electrode assembly, the method that is called as hot stamped process is arranged.That is, at first, mixed solvent and become the resin etc. of binding agent and make catalyst ink in catalyst.Then,, for example implemented the carbon paper etc. of hydrophobic treatment and gone up the described catalyst ink of coating, made it dry, formed catalyst layer, made porous electrode at gas diffusion layers.Then, utilize drop stamping etc. bonding from the two sides of polyelectrolyte membrane the porous electrode made as mentioned above, finish MEA.
In addition, in described although understand a part, but be called as the method for transfer printing in addition as the manufacture method of membrane-electrode assembly.That is, can enumerate and make it dry and directly form and make catalyst layer in advance on the method for catalyst layer, the base material and be transferred to method on the polyelectrolyte membrane etc. at film etc. in the surface coated catalyst ink of polyelectrolyte membrane.
But, in mode of printing in the past and the cylinder mode in the past, because with the coating formation separately of first catalyst layer, dielectric substrate and second each layer of catalyst layer, thereby the low problem of productivity is arranged.
In addition, in the cylinder mode in the past, after making the first catalyst layer bone dry, reel.Before first catalyst layer of reeling, when making the first catalyst layer bone dry, a lot of spaces appears in first catalyst layer, form the high layer of vesicularity.So when being coated with the coating of the raw material that becomes dielectric substrate on first catalyst layer, the coating of dielectric substrate just immerses in the space that is formed in first catalyst layer, consequently, produces the result of electrical property variation.
That is, in the cylinder mode in the past, the coating of dielectric substrate enters because of making in the dry space that forms of first catalyst layer, produces the problem of electrical property variation.
In addition, in the cylinder mode in the past, when the coating of the raw material that will become dielectric substrate is coated with simultaneously with the coating that becomes the raw material of second catalyst layer, the coating that becomes the raw material of described dielectric substrate takes place to flow, make the thickness inequality of dielectric substrate, in addition, first catalyst layer is contacted with second catalyst layer, consequently, produce the result of electrical property variation.That is, compare with the coating of the raw material that becomes second catalyst layer, the dope viscosity of raw material that becomes dielectric substrate is lower.Therefore, the coating that becomes the raw material of dielectric substrate is compared easier flowing with the coating of the raw material that becomes second catalyst layer.Like this, electrical property is with regard to variation.
That is, in the cylinder mode in the past, will become the coating of electrolytical raw material and become way that the coating of the raw material of second catalyst layer is coated with simultaneously because therefore the electrical property variation has irrealizable problem.
In addition, in the membrane-electrode assembly in the past, though carried out making second catalyst layer, one side to compare the work that contains noble metals such as more platinum with first catalyst layer, or make second catalyst layer, one side compare work such as thicker, but require to make the internal resistance of membrane-electrode assembly littler with first catalyst layer.
That is, the lower in the past problem of internal resistance ratio that makes membrane-electrode assembly is arranged.
In addition, in the described hot stamped process or transfer printing in the past, might cause following problem.
1. when carrying out punching press etc. after independent making the with polyelectrolyte layers and/or each layer of catalyst layer, process number is more, is difficult to improve the productivity of MEA.
2. when after having made each layer, carrying out each layer of MEA bonding, in catalyst layer and polyelectrolyte membrane bonding, require delicate adjustment, on both interfaces, produce small gap etc., thus the situation that has catalyst layer to separate with polyelectrolyte membrane.When using this kind MEA, just can't bring into play the performance of battery fully.
3. when catalyst ink directly being coated on polyelectrolyte membrane surperficial, the mechanical strength of polyelectrolyte membrane is generally less, polyelectrolyte membrane dissolves, expands because of solvent composition contained in the catalyst ink, and going up in these areas all becomes problem, can't obtain good MEA.At this moment, just might become short circuit between the catalyst layer that causes the clamping polyelectrolyte membrane, the reason of leakage etc.
As the method that solves described problem, developed " the while coating process " of roughly coating side by side successively on base material, stacked catalyst ink, polyelectrolyte coating, catalyst ink.Simultaneously in the coating process,, concentrate in stacked back and carry out dried, therefore the separation that just is difficult to produce each interlayer for dried catalyst layer and polyelectrolyte layers because before layer (dope layer) drying that is made of each coating, coating is a kind of coating down.In addition, can reduce process number,, then can also realize the continuous production of MEA, thereby productivity is improved if in addition base material is transferred continuously.
But, in the described while coating process, on the surface that becomes the catalyst layer of the superiors (being formed at the catalyst layer on the polyelectrolyte layers), might produce very big be full of cracks.Think that as reason because following mechanism etc., that is, the volume contraction of the catalyst ink layer when dry is subjected to the influence as the flowability of the polyelectrolyte dope layer of lower floor, develops into the very big be full of cracks of dried catalyst layer surface.When having produced very big be full of cracks in catalyst layer surface, the density of catalyst of catalyst layer just diminishes, and perhaps catalyst layer comes off from the part of be full of cracks, thereby the discharge rate of battery or the situation that cycle life characteristics reduces are arranged.
Summary of the invention
The present invention considers described problem, and purpose is, the manufacture method of the fuel battery membrane electrode assembly that the productivity that makes fuel cell and performance significantly improve, the manufacturing installation and the membrane-electrode assembly of fuel battery membrane electrode assembly are provided.
That is, the present invention considers described problem, and purpose is, the manufacture method of the high fuel battery membrane electrode assembly of productivity and the manufacturing installation of fuel battery membrane electrode assembly are provided.
In addition, the present invention considers described problem, purpose is, provides the coating that does not have dielectric substrate to enter in the space that is formed in first catalyst layer and makes the manufacture method of fuel battery membrane electrode assembly of situation of electrical property variation and the manufacturing installation of fuel battery membrane electrode assembly.
In addition, the present invention considers described problem, purpose is, even the coating that the coating that will become electrolytical raw material is provided and becomes the raw material of second catalyst layer is coated with simultaneously, the manufacture method of the fuel battery membrane electrode assembly that electrical property can variation yet and the manufacturing installation of fuel battery membrane electrode assembly.
In addition, the present invention considers described problem, and purpose is, the lower membrane-electrode assembly of internal resistance of membrane-electrode assembly compared with the past is provided.
In addition, the present invention considers described problem, purpose is, the surface that is provided at the catalyst layer that becomes the superiors can not produce very big be full of cracks, the fuel battery membrane electrode assembly that the discharge rate of battery or cycle life can not reduce, the manufacture method of fuel battery membrane electrode assembly, fuel cell polyelectrolyte coating and polymer electrolyte fuel cells.
In order to solve described problem, one of the present invention is the manufacture method of following fuel battery membrane electrode assembly, that is, possess:
To comprise the 1st catalyst and the 1st coating with resin of hydrogen to be coated on the base material and form the 1st layer the 1st operation,
The 2nd coating that will comprise resin with hydrogen be coated on described the 1st layer go up and form the 2nd layer the 2nd operation,
Before described the 2nd layer of drying, will comprise the 2nd catalyst and have the resin of hydrogen and the 3rd coating of solvent is coated on described the 2nd layer and goes up and form the 3rd layer, make and comprise described the 1st layer, the 3rd operation of described the 2nd layer and described the 3rd layer laminated body,
Described solvent comprises 1 boiling point under the air pressure at the organic solvent more than 120 ℃ with the ratio more than the 40 weight %,
The temperature of the operation more than 90% in the middle of the drying process of described laminated body drying is in 60 ℃ to 80 ℃ scope.
In addition, the present invention's two is manufacture methods of following fuel battery membrane electrode assembly, that is, possess:
To comprise the 1st catalyst and the 1st coating with resin of hydrogen to be coated on the base material and form the 1st layer the 1st operation,
The 2nd coating that will comprise resin with hydrogen be coated on described the 1st layer go up and form the 2nd layer the 2nd operation,
Before described the 2nd layer of drying, will comprise the 2nd catalyst and have the resin of hydrogen and the 3rd coating of solvent is coated on described the 2nd layer and goes up and form the 3rd layer, make and comprise described the 1st layer, the 3rd operation of described the 2nd layer and described the 3rd layer laminated body,
Described solvent is pressed in the following organic solvent of 1.06kPa (8mmHg) with the saturated steam that the ratio more than the 40 weight % comprises under 20 ℃,
The temperature of the operation more than 90% in the middle of the drying process of described laminated body drying is in 60 ℃ to 80 ℃ scope.
In addition, the present invention's three is manufacture methods of following the present invention's two fuel battery membrane electrode assembly, that is, the saturated steam that described solvent comprises under 20 ℃ is pressed in the following organic solvent of 0.20kPa (1.5mmHg).
In addition, the manufacture method of the present invention's four any one fuel battery membrane electrode assembly that is one of following the present invention in three, that is, described solvent comprises the organic solvent with the compound of following general formula (A) expression.
R 1-O-(R 2O) n-H (A)
Wherein, in the described general formula (A),
R 1For from CH 3, C 2H 5, C 3H 7And C 4H 9Middle 1 functional group who selects,
R 2For from C 2H 4And C 3H 6Middle 1 functional group who selects,
N is 1 integer selecting from 1,2 and 3.
In addition, the present invention's five is manufacture methods of following fuel battery membrane electrode assembly, that is, possess:
To comprise the 1st catalyst and the 1st coating with resin of hydrogen to be coated on the base material and form the 1st layer the 1st operation,
The 2nd coating that will comprise resin with hydrogen be coated on described the 1st layer go up and form the 2nd layer the 2nd operation,
To comprise the 2nd catalyst and have the resin of hydrogen and the 3rd coating of solvent is coated on described the 2nd layer and goes up and form the 3rd layer, and make and comprise described the 1st layer, the 3rd operation of described the 2nd layer and described the 3rd layer laminated body,
Described the 2nd coating comprises gelating agent.
In addition, the present invention's six is manufacture methods of following the present invention's five fuel battery membrane electrode assembly, that is, described gelating agent is the thermal sensitivity gelating agent.
In addition, the present invention's seven is manufacture methods of following the present invention's five or six fuel battery membrane electrode assembly, that is, described the 2nd coating comprises described gelating agent with the ratio below the 33 weight %.
In addition, the present invention's eight is manufacture methods of any one fuel battery membrane electrode assembly among one of following the present invention, two, five, that is, described the 2nd coating comprises thickener with the ratio below the 33 weight %.
In addition, the present invention's nine is manufacture methods of any one fuel battery membrane electrode assembly among one of following the present invention, two, five, that is, and and 25 ℃ of temperature, shear rate 1s -1Under the viscosities il of described the 2nd coating 1With 25 ℃ of temperature, shear rate 1s -1Under the viscosities il of described the 3rd coating 2Satisfy the relation shown in the following formula.
1/25≤η 1/η 2≤25
Wherein, in the described formula, η 1＞0, η 2＞0
In addition, the present invention's ten is manufacture methods of following the present invention's nine fuel battery membrane electrode assembly, that is, and and described η 1With described η 2Satisfy η 1＞η 2Relation.
In addition, the present invention's 11 is the manufacture method of any one fuel battery membrane electrode assembly among one of following the present invention, two, five, promptly, described the 2nd catalyst is the solid content that has supported noble metal, and described the 3rd coating is to utilize to comprise the coating that makes in the operation of ratio operation of mixing under the state more than the 20 weight % of described the 2nd catalyst with described the 2nd catalyst, as the 1st solvent of at least 1 composition of described solvent.
In addition, the present invention's 12 is manufacture methods of following the present invention's 11 fuel battery membrane electrode assembly, that is, described the 1st solvent is with respect to the highest solvent of described the 2nd solvent compatibility in the middle of the composition of described solvent.
In addition, the present invention's 13 is manufacture methods of any one fuel battery membrane electrode assembly among one of following the present invention, two, five, that is, described base material is transferred continuously, carries out described the 1st operation, described the 2nd operation and described the 3rd operation successively.
In addition, the present invention's 14 be possess fuel battery membrane electrode assembly that the manufacture method of any one fuel battery membrane electrode assembly among one of the present invention of utilizing, two, five makes, to the polymer electrolyte fuel cells of the barrier film of described fuel battery membrane electrode assembly supply response gas.
In addition, the present invention's 15 is a following fuel cell polyelectrolyte coating,, comprises the resin with hydrogen, the 2nd solvent, the gelating agent of the described resin of dissolving that is.
In addition, the present invention's 16 is following the present invention's 15 a fuel cell polyelectrolyte coating, that is, described gelating agent is the thermal sensitivity gelating agent.
In addition, in addition, the present invention's 17 is following the present invention's 15 or 16 a fuel cell polyelectrolyte coating,, contains described gelating agent with the ratio below the 33 weight % that is.
In addition, the present invention's 18 is following fuel battery membrane electrode assemblies, that is, be the folder every polyelectrolyte layers with hydrogen and with a pair of catalyst layer stacked fuel battery membrane electrode assembly, described polyelectrolyte layers is a porous layer.
In addition, the present invention's 19 is following polymer electrolyte fuel cells,, possesses the present invention's 18 fuel battery membrane electrode assembly, to the barrier film of described fuel battery membrane electrode assembly supply response gas that is.
In addition, the present invention's 20 is manufacture methods of following fuel battery membrane electrode assembly, that is, possess:
On the base material that moves, by be coated with the 1st catalyst layer that the 1st coating forms the 1st catalyst layer form operation,
During being in wet condition at described the 1st catalyst layer, the 2nd coating is coated on described the 1st catalyst layer and the electrolyte that forms dielectric substrate form operation,
Make described dielectric substrate according to the thickness that is held wet condition reach the mode drying of specific thickness drying process,
Form operation by the 3rd coating being coated on the 2nd catalyst layer that forms the 2nd catalyst layer on the described dielectric substrate that has been dried,
Described the 1st catalyst layer and described the 2nd catalyst layer are respectively the hydrogen utmost point and the oxygen utmost point, perhaps are respectively the oxygen utmost point and the hydrogen utmost point.
In addition, the present invention's 21 is the manufacture method of following the present invention's 20 fuel battery membrane electrode assembly, that is, the baking temperature of described drying process is in the scope below 150 ℃ more than 20 ℃.
In addition, the present invention's 22 is manufacture methods of following the present invention's 20 or 21 fuel battery membrane electrode assembly, that is, and and in the hot-blast outlet portion of described drying process and the scope of the distance of described dielectric substrate below the above 500mm of 10mm.
In addition, the present invention's 23 is manufacture methods of following the present invention's 22 fuel battery membrane electrode assembly, that is, in the scope of flow velocity below the above 20m of per second 1m of the hot blast of the position of the described hot-blast outlet 10mm of portion of the distance of described drying process.
In addition, the present invention's 24 is manufacturing installations of following fuel battery membrane electrode assembly, that is, possess:
The 1st catalyst layer that forms the 1st catalyst layer by coating the 1st coating on the base material that moves form mechanism,
During being in wet condition at described the 1st catalyst layer, the 2nd coating is coated on described the 1st catalyst layer and the electrolyte that forms dielectric substrate form mechanism,
Make described dielectric substrate according to the thickness that is held wet condition reach the mode drying of specific thickness drier,
Form mechanism by the 3rd coating being coated on the 2nd catalyst layer that forms the 2nd catalyst layer on the described dielectric substrate that has been dried,
Described the 1st catalyst layer and described the 2nd catalyst layer are respectively the hydrogen utmost point and the oxygen utmost point, perhaps are respectively the oxygen utmost point and the hydrogen utmost point.
In addition, the present invention's 25 is following fuel battery membrane electrode assemblies, that is, possess: the hydrogen utmost point, be formed at dielectric substrate that described hydrogen extremely goes up, be formed at the oxygen utmost point on the described dielectric substrate, the described oxygen utmost point one side compares with the described hydrogen utmost point, and the area that contacts with described dielectric substrate is bigger.
Description of drawings
Fig. 1 is the skeleton diagram of the membrane-electrode assembly of embodiments of the present invention 1.
Fig. 2 is the skeleton diagram of manufacturing installation of the membrane-electrode assembly of expression embodiments of the present invention 1.
Fig. 3 is the profile of the membrane-electrode assembly of embodiments of the present invention 1.
Fig. 4 is the schematic diagram of example of the manufacture method of expression membrane-electrode assembly of the present invention.
Fig. 5 is the schematic diagram of example of employed apparatus for coating in the manufacture method of expression membrane-electrode assembly of the present invention.
Fig. 6 is the schematic diagram of the configuration example of expression membrane-electrode assembly of the present invention.
Fig. 7 is the profile of the configuration example of expression membrane-electrode assembly of the present invention.
Fig. 8 is the schematic diagram of example of the manufacture method of expression membrane-electrode assembly of the present invention.
Fig. 9 is the schematic diagram of the configuration example of expression fuel cell of the present invention.
Figure 10 is the figure that the operation of the membrane-electrode assembly of making mode of printing in the past is described.
Figure 11 is the figure that the operation of the membrane-electrode assembly of making mode of printing in the past is described.
Figure 12 is the figure that the operation of the membrane-electrode assembly of making mode of printing in the past is described.
Figure 13 is the figure that the operation of the membrane-electrode assembly of making mode of printing in the past is described.
Figure 14 is the figure that the operation of the membrane-electrode assembly of making cylinder mode in the past is described.
Figure 15 is the figure that the operation of the membrane-electrode assembly of making cylinder mode in the past is described.
Among the figure: 1,2 nozzles, 3a, the 3b aspirator, 4 driers, 5,6,7 paint feeding devices, 9,9a, the 9b base material, 10 cylinders, the coating that 11 first catalyst layers are used, the coating that 12 polyelectrolyte layers are used, the coating that 13 second catalyst layers are used, 15 polyelectrolytes, 16 die for extrusion molding, 17 extrusion shapers, 18 hot transfer platen, 19 printing moulds, 20 printing cutter heads, 21 plates, 22 cutter heads, 201 first catalyst layers, 301 polyelectrolyte layers, 401 second catalyst layers, 202,302,402 slits, 203,303,403 arms, 501,601,701 jars, 502,602,702 pumps, 503,703 three-way valves, 1001,1101 base materials, 1002,1004,1102,1104 catalyst ink, 1003,1103 polyelectrolyte coating, 1021,1041,1121,1141 catalyst ink layers, 1031,1131 polyelectrolyte dope layers, 1022,1042,1122,1142 catalyst layers, 1032,1132 polyelectrolyte layers, 1051,1052,1053,1055,1151,1152,1153 apparatus for coating, 1054,1154 drying devices, 1231 membrane-electrode assemblies, 1232,1233 gas diffusion layers, 1234,1235 barrier films
Embodiment
Below with reference to accompanying drawings embodiments of the present invention are described.
(execution mode 1)
At first, execution mode 1 is described.
Fig. 1 represents the summary pie graph of employed membrane-electrode assembly in the present embodiment.In addition, Fig. 3 represents the profile of PP '.9 when membrane-electrode assembly made continuously the base material of employed band shape, form each layer thereon.
201 is first catalyst layer, is formed on the base material 9.In addition, 301 is polyelectrolyte layers, is formed on first catalyst layer 201.In addition, 401 is second catalyst layer, is formed on the polyelectrolyte layers 301.
And the 1st catalyst layer 201 is to be used as the layer that the hydrogen utmost point uses, and the 2nd catalyst layer 401 is to be used as the layer that the oxygen utmost point uses.
Employed membrane-electrode assembly is following in the present embodiment makes.
That is, the base material 9 of PETG system or polypropylene system moves continuously.In addition, on the base material 9 that moves continuously, the slit that the noble metal that has mixed catalyst such as supporting platinum or platinum alloy supports carbon dust, coating with the fluorine-type resin of hydrogen ion conductivity and solvent passes nozzle is extruded and is coated with bandedly, form first catalyst layer 201.
Here as carbon dust, can use acetylene black, Kai Qihei electrical conductivity Carbon blacks such as (ketjen black).
In addition, as fluorine-type resin, polyphenyl dioctyl phthalate glycol ester, Kynoar, Kynoar-hexafluoropropylene copolymer, perfluorinated sulfonic acid etc. can be used separately or use multiple.
In addition, as solvent, water, ethanol, methyl alcohol, isopropyl alcohol, ethylene glycol, methylene glycol, propylene glycol, methyl ethyl ketone, acetone, toluene, dimethylbenzene, n methyl-2-pyrroles's phosphorus ketone etc. can be used separately or use multiple.In addition, if the addition of solvent is made as 100 with carbon dust, then represent to adopt 10～3000 to get final product with weight ratio.
With the formation of first catalyst layer 201 simultaneously, to be that slit that the coating of principal component passes nozzle is extruded and is coated with on first catalyst layer 201 and becomes band with fluororesin, form the double-deck laminated tape that constitutes by first catalyst layer 201 and polyelectrolyte 301 with hydrogen ion conductivity.Owing to during first catalyst layer 201 be wet condition, form polyelectrolyte layers 301, so do not have the situation that the coating of polyelectrolyte layers 301 soaks into to first catalyst layer 201.
Then, by the double-deck laminated tape drying that will constitute by first catalyst layer 201 and polyelectrolyte layers 301, the dry tack free of polyelectrolyte layers 301 is solidified with drier.
Then, will mix noble metal supports carbon dust, coating with the resin of hydrogen ion conductivity and solvent passes nozzle slit to extrude and be coated with and become band, on polyelectrolyte layers 301, formed second catalyst layer 401.The average film thickness that adopts first catalyst layer 201 and second catalyst layer 401 is 3～160 μ m, and the average film thickness of polyelectrolyte layers is that the scope of 6～200 μ m gets final product.
Like this, just made stacked three layers ribbon (hereinafter referred to as three laminated tapes).Here, when coating composition, be necessary to make the width W 1 of first catalyst layer 201, the width W 2 of second catalyst layer 401 to satisfy W1≤W2.That is, be necessary that the mode that is not less than the width of first catalyst layer 201 according to the width that makes second catalyst layer 401 forms first catalyst layer 201 and second catalyst layer 401.
At last, three layer laminate bands are peeled off from base material 9, stamping-out is specific shape, makes three layer laminate body, i.e. membrane-electrode assemblies of three-layer structure.
The skeleton diagram of the manufacturing installation of the membrane-electrode assembly that uses in the expression present embodiment among Fig. 2.At first, the formation to the manufacturing installation of membrane-electrode assembly describes.1,2 is respectively the nozzle of ejection coating on base material 9,11 is the coating that first catalyst layer is used, 12 coating of using for polyelectrolyte, 13 is the coating that second catalyst layer is used, 202,303,402 be respectively slit, 203,303,403 are respectively arm, and 3a, 3b are respectively suction (sackbag) device, 4 is drier, and 5,6,7 are respectively paint feeding device.
Here, aspirator 3a, 3b are respectively the mechanisms of aspirating the coating in each arm 203,303,403 for from each slit 202,302,402 discontinuous ground coating composition of nozzle 1,2.
Drier 4 is to make at bilayer to be coated with simultaneously and the mechanism of the dry tack free of first catalyst layer 201 that forms and polyelectrolyte layers 301.
In addition, paint feeding device 5 is devices of supplying with coating in arm 203, by coating store the liquid-feeding pump 502 of jar 501, the coating of usefulness, the three-way valve 503 of switching that carries out the liquor charging direction of coating constitutes.
Paint feeding device 7 also is identical formation, and paint feeding device 6 is except possessing three-way valve, with paint feeding device the 5, the 7th, identical formation.
In addition, 10 is metal cylinder, is the mechanism that base material 9 is transferred continuously.
Below, the action of the manufacturing installation of the membrane-electrode assembly of this kind present embodiment is described.
The manufacturing installation of the membrane-electrode assembly that uses in the present embodiment, on nozzle 1, possess slit 202,302, arm 203,303, paint feeding device 5,6, with nozzle 1 first catalyst layer 201 and polyelectrolyte layers 301 are coated with simultaneously, on nozzle 2, possess slit 402, arm 403, paint feeding device 7, be utilized coating second catalyst layer 401 on first catalyst layer 201 that nozzle 2 is coated with simultaneously and the polyelectrolyte 301.
Here, according to making first catalyst layer 201 on base material 9, be formed the mode of the rectangular shape of proper alignment, switch three-way valve 503 at certain intervals, stopping when the coating of nozzle 1 is supplied with, make the aspirator 3a action of suction coating, in the coating 11 of suction nozzle 1 inside, supply with coating off and on.
In addition, polyelectrolyte layers 301 is owing to be coated with for during the wet condition at the 1st catalyst layer 201, therefore do not have polyelectrolyte layers 301 and soaks into and situation that electrical characteristics are worsened to the inside of the 1st catalyst layer 201.
In addition, second catalyst layer 401 is identical with first catalyst layer 201, and the mode that overlaps according to the rectangular shape that makes outer rim with first catalyst layer 201 is with first catalyst layer 201 coating composition 13 off and in the same manner.
In addition, polyelectrolyte layers 301 is to supply with coating 12 and become band ground coating continuously to arm 303 and slit 302.
At this moment, when the length with the direct of travel of the base material 9 of the rectangular shape of first catalyst layer 201 is made as L1, when the length of the described direct of travel of the base material 9 of the rectangular shape of second catalyst layer 401 was made as L2, then the mode according to the condition that satisfies L1≤L2 was coated with.That is, the mode of length of direct of travel that is not less than the rectangular shape of the 1st catalyst layer 201 according to the length of the direct of travel of the rectangular shape that makes second catalyst layer 401 is coated with.
And, in the present embodiment, following describing, promptly, width W 1 when first catalyst layer 201, the width W 2 of second catalyst layer 401 satisfies W1≤W2, the length of the direct of travel of the base material 9 of the rectangular shape of first catalyst layer 201 is made as L1, when the length of the described direct of travel of the base material 9 of the rectangular shape of second catalyst layer 401 is made as L2, then the mode according to the condition that satisfies L1≤L2 is coated with, in brief, need only the area that with dielectric substrate 301 contact of the area that contacts with dielectric substrate 301 of second catalyst layer 401 greater than first catalyst layer 201.
The feature of present embodiment is, the drier 4 between nozzle 1 and the nozzle 2 is located in utilization, soon hygrometric state thickness is made as 100% behind the forming of the double-deck laminated tape that will be made of catalyst layer 201 and dielectric substrate 301, according to making hygrometric state thickness reach mode drying on cylinder 10 of 20～90%, be coated with second catalyst layer 401, form three layer laminate bands on the whole thereafter.
That is,, for example can use hot air blower, infrared heater etc. as drier 4.As its baking temperature,, then there is not drying effect if less than 20 ℃, if more than 150 ℃, then because the burning of the 1st catalyst layer 201, therefore preferred 20 ℃～150 ℃ scope is for the thermal source of drier 4 and the distance on double-deck laminated tape surface, if hot air blower, during then less than 10mm, can make the surface of filming disorderly, be longer than under the situation of 500mm because of wind, heat is diffusion towards periphery, the scope that therefore preferred 10mm is above and 500mm is following.In addition, preferably be in scope from 1m/s to 20m/s apart from the wind speed of the hot blast of the hot air blow port 10mm position of hot air blower.
If infrared heater, then owing to thermal source can not contact with double-deck laminated tape surface, as long as be in the scope of infrared ray arrival, so the scope from infrared heater to the preferred 10mm～1000mm of distance that films.
And, in the present embodiment,, be not limited thereto though the situation that formed first catalyst layer 201 before second catalyst layer 401 is illustrated, also can before first catalyst layer 201, form second catalyst layer 401.That is, both can also can extremely form the hydrogen utmost point in the back forming the extremely back formation oxygen utmost point of hydrogen at formation oxygen.
In addition, in the present embodiment, though the situation that first catalyst layer 201 and dielectric substrate 301 are formed simultaneously is illustrated, but be not limited thereto, so long as during the 1st catalyst layer 201 is in wet condition, also can after the formation of the 1st catalyst layer 201, form dielectric substrate 301.
And, the nozzle 1 of present embodiment, slit 202 are examples that the 1st catalyst layer of the present invention forms mechanism, the nozzle 1 of present embodiment, slit 302 are examples that dielectric substrate of the present invention forms mechanism, and the nozzle 2 of present embodiment, slit 402 are examples that the 2nd catalyst layer of the present invention forms mechanism.
To concentrate below the effect of present embodiment 1 and to describe.
Owing to the drier of being located at by use between nozzle 1 and the nozzle 24, on cylinder 10, make it dry, just transmitted in the inner heat of getting up of piling up of the double-deck laminated tape that constitutes by first catalyst layer 201 and polyelectrolyte layers 301, therefore only near the curing that is dried of the top layer of dielectric substrate 301 to cylinder 10.So because second catalyst layer 401 can't soak into to dielectric substrate 301, so adhesive strength is obviously stronger, can obtains to form interface clearly and the membrane-electrode assembly of crackle does not take place on catalyst layer 301.
In addition, because first catalyst layer 201 is in wet condition, therefore do not have the situation of soaking into the electrical characteristics deterioration that makes first catalyst layer 201 because of dielectric substrate 301 to the inside of first catalyst layer 201 yet.
In addition, because the mode of the area that contacts with dielectric substrate 301 greater than first catalyst layer 201 according to the area that second catalyst layer 401 is contacted with dielectric substrate 301 constitutes, so just can dwindle the internal resistance of membrane-electrode assembly.
Like this, utilize the generating efficiency or the life characteristic of the fuel cell that the membrane-electrode assembly of present embodiment makes to significantly improve.
Like this, according to present embodiment, just can provide the flatness on surface of each layer good, the manufacture method of the uneven less fuel battery membrane electrode assembly of thickness.
(execution mode 2)
Fig. 4 is the operation schematic diagram of an example of the manufacture method of expression MEA of the present invention.In the example shown in Figure 4, banded base material 1001 is transferred continuously, is coated with catalyst ink 1002, polyelectrolyte coating 1003 and catalyst ink 1004 on base material 1001 successively.The coating of catalyst ink 1002, polyelectrolyte coating 1003 and catalyst ink 1004 utilizes apparatus for coating 1051,1052 and 1053 to carry out respectively.
In addition, in the example shown in Fig. 4, polyelectrolyte coating 1003 is coated on the catalyst ink layer 1021, and before polyelectrolyte dope layer 1031 dryings, catalyst ink 1004 is coated on the polyelectrolyte dope layer 1031.And the what is called of this specification " dry before " is meant, in polyelectrolyte dope layer 1031, and the state of the concentration of polyelectrolyte below about 30 weight %.Thereafter, each dope layer device 1054 dryings that are dried if remove base material 1001, then can obtain to comprise stacked the MEA of the structure of catalyst layer 1022, polyelectrolyte layers 1032 and catalyst layer 1042.
According to the manufacture method shown in the present embodiment, form owing to being coated on the base material successively by each layer that will constitute MEA, therefore just do not need with the operation of the independent making of each layer difference, with each layer transfer printing of made, the operation of drop stamping etc.Thus, just can cut down the number in man-hour, thereby the productivity of MEA is further improved.
In addition, and make each layer is independent, use the situation of makings MEA such as transfer printing or hot stamped process to compare thereafter, the catalyst layer of formation MEA and the cementability of polyelectrolyte layers are more good, can suppress the separation at interface or come off.
In addition, because before polyelectrolyte dope layer 1031 dryings, catalyst ink 1004 is coated on the polyelectrolyte dope layer 1031, therefore just can suppress as situation about catalyst ink directly being coated on the polyelectrolyte membrane, the problem that the dissolving of the polyelectrolyte membrane that causes because of contained solvent in the mechanical strength deficiency of polyelectrolyte membrane or the catalyst ink, expansion etc. cause, thus the stable MEA of the less power generation characteristics of textural defective can be obtained.
Here, as the solvent of coating the catalyst ink 1004 on the polyelectrolyte dope layer 1031, use to contain as the boiling point under 1 atmospheric pressure to get final product at the solvent of the organic solvent more than 120 ℃ with the ratio more than the 40 weight %.At this moment, if in the operation more than 90% in the middle of drying process described later, baking temperature is in 60 ℃ to 80 ℃ scope, just can obtain the stable MEA of the less power generation characteristics of constructional defective.
In addition, as the solvent of catalyst ink 1004, also can use the saturated steam that contains under 20 ℃ with the ratio more than the 40 weight % to be pressed in the following organic solvent of 1.06kPa (8mmHg).Wherein, the saturated steam that preferably contains under 20 ℃ is pressed in the following organic solvent of 0.20kPa (1.5mmHg).At this moment, if in the operation more than 90% in the middle of drying process described later, baking temperature is in 60 ℃ to 80 ℃ scope, just can obtain the stable MEA of the less power generation characteristics of constructional defective.
By adopting aforesaid catalyst ink 1004, brushing technique was compared with in the past the time, just can be suppressed at the be full of cracks that produces on the surface of the catalyst layer (being formed at the catalyst layer on the polyelectrolyte layers) that becomes the superiors, thereby can obtain the more stable MEA of constructional defective power generation characteristics still less.Thus, if use described MEA, then can obtain the fuel cell that the discharge rate of battery or life characteristic have further improved.
If use aforesaid catalyst ink 1004, then the rate of drying of catalyst ink layer 1041 is compared with speed in the past and is become littler.Can think thus, compare with the speed of catalyst ink layer 1041 drying, because of the flowability of catalyst ink 1004 self is bigger relatively with the speed of catalyst ink layer 1041 surface smoothingization (levellingization), thus the generation that can suppress to chap.
And, be not only catalyst ink 1004, polyelectrolyte coating 1003 and/or the catalyst ink of coating on the base material 1002 also can contain described solvent.In addition, catalyst ink 1004 both can be an anode catalyst coating, also can be cathod catalyst coating.But if catalyst ink 1004 and catalyst ink 1,002 one sides are anode catalyst coating, then the opposing party just becomes cathod catalyst coating.
In addition, described organic solvent preferably contains the compound with following general formula (A) expression.
R 1-O-(R 2O) n-H (A)
Wherein, in described general formula (A), R 1For from CH 3, C 2H 5, C 3H 7And C 4H 9Middle 1 functional group who selects, R 2For from C 2H 4And C 3H 6Middle 1 functional group who selects, n are 1 integer selecting from 1,2 and 3.
Multivalence 01 derivatives with described general formula (A) expression does not contain water-disintegrable functional groups such as ester functional group or amide functional base, the excellent in stability in coating.In addition, particularly in catalyst ink, contain under the situation of the stronger material of acid degree (binding agent etc.), produce effect for the stabilisation of coating proterties.
Organic solvent as with described general formula (A) expression for example can be used alone or as a mixture dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, propylene glycol-n-propyl ether, DPG-n-propyl ether, propylene glycol-n-butyl ether, DPG-n-butyl ether, tripropylene glycol-n-butyl ether etc.
In addition, be pressed in the following organic solvent of 0.20kPa (1.5mmHg), can use PGDA etc. as the saturated steam under 20 ℃.
In addition, 25 ℃ of temperature, shear rate 1s -1Under the viscosities il of polyelectrolyte coating 1003 1With 25 ℃ of temperature, shear rate 1s -1Under the viscosities il of catalyst ink 1004 2Preferably satisfy the relation shown in the following formula (1).
1/25≤η 1/η 2≤25 (η 1＞0，η 2＞0) (1)
When polyelectrolyte coating 1003 and catalyst ink 1004 satisfy described the relation, because the polyelectrolyte coating 1003 in the low shearing speed zone and the differences in viscosity of catalyst ink 1004 diminish, the be full of cracks generation in the time of therefore just can suppressing catalyst layer 1042 that the flowability by polyelectrolyte dope layer 1031 causes and form.
In addition, wherein, especially preferably satisfy η 1＞η 2Relation.At this moment, because the flowability of polyelectrolyte dope layer 1031 further diminishes, the effect that the be full of cracks when therefore suppressing catalyst layer 1042 formation produces will further become big.
And the coating of polyelectrolyte dope layer 1031 also can utilize the batch processing operation to carry out.In addition, for the coating of catalyst ink layer 1041,, then also can utilize the batch processing operation to carry out if before polyelectrolyte dope layer 1031 dryings.And, particularly such at example as shown in Figure 4, being coated with continuously under the situation of each coating on the base material of the band shape of being transferred continuously, can further realize productive raising.
In addition, apparatus for coating not necessarily all needs 1 for each coating as shown in Figure 4, also can use the apparatus for coating of the coating of carrying out multiple coating.An example of apparatus for coating is illustrated among Fig. 5.
In the example shown in Figure 5, by utilizing apparatus for coating 1055, on the base material of being transferred continuously 1001, with polyelectrolyte coating 1003 and roughly coating continuously side by side of catalyst ink 1004, catalyst ink layer 1021, polyelectrolyte dope layer 1031 and catalyst ink layer 1041 are layered on the base material 1001.At this moment, will before polyelectrolyte dope layer 1031 dryings, catalyst ink 1004 be coated on the polyelectrolyte dope layer 1031.
Below, catalyst ink and polyelectrolyte coating are described.
Polyelectrolyte coating is so long as contain the coating of the resin with hydrogen and get final product.As described resin, for example can use perfluoroethylene sulfonic acid resinoid, with the vinyl sulfonic acid resinoid partially fluorinated resin, hydrocarbon resins etc.Wherein, preferably use perfluor resinoids such as perfluoroethylene sulfonic acid.
In addition, as employed solvent in the polyelectrolyte coating, though get final product so long as can dissolve described solvent with resin of hydrogen, consider from the easness of painting process, drying process, preferably make water, ethanol, 1-propyl alcohol etc.The scope of the preferred 20 weight % of the content of the resin in the polyelectrolyte coating～30 weight %, the scope of preferred especially 22 weight %～26 weight %.Will be formed on the porous polyelectrolyte layers that the surface possesses appropriateness, the characteristic of the MEA of gained improves.
In addition, polyelectrolyte coating preferably contains thickener.Because by containing thickener, the flowability of polyelectrolyte dope layer further diminishes, the effect that the be full of cracks when therefore suppressing the catalyst layer formation on the polyelectrolyte layers produces will further become big.
The ratio that 33 weight % of the preferred polyelectrolyte coating of thickener are following.In this scope, can suppress deterioration as the hydrogen ion transport properties of polyelectrolyte layers.As thickener, for example can use ethyl cellulose, polyvinyl alcohol etc.In addition, wherein, contain thickener particularly preferably in the scope with 10 weight %～33 weight % in the polyelectrolyte coating.
Catalyst ink so long as contain gets final product the catalyst of the conductivity that described electrochemical reaction carries out.In order to obtain good characteristic, the pulverous material of preferred use in described catalyst as coating.As described catalyst, for example can use the carbon dust that has supported noble metal.
When use has supported the carbon dust of noble metal,, can use platinum etc. as noble metal.And, under the situation that forms anode catalyst layer after the coating, when in anode, not being to use pure hydrogen, and when being to use the reformed gas that contains CO etc., preferably also contain ruthenium etc.
In addition, as carbon dust, can use conductive carbon powders such as Kai Qihei (ketjen black), acetylene black.The scope of the preferred 100nm～500nm of its average grain diameter.
As employed solvent in the catalyst ink, water, ethanol, methyl alcohol, isopropyl alcohol, ethylene glycol, methylene glycol, propylene glycol, methyl ethyl ketone, acetone, toluene, dimethylbenzene equal solvent can be used alone or as a mixture.The addition of solvent is the scope of 10 weight portions～400 weight portions preferably with respect to carbon dust 100 weight portions.
In addition, in catalyst ink, preferably contain resin with hydrogen.Wherein, preferred fluorine-type resin.As fluorine-type resin with hydrogen, can independent or mixing various kinds of resin use with polyvinyl fluoride, Kynoar, Kynoar-hexafluoropropylene copolymer, perfluoroethylene sulfonic acid, polyvinyl fluoride-perfluoroethylene sulfonic acid copolymerization body etc.
In addition, in catalyst ink, can add binding agent, dispersant, thickener etc. as required again.
The solid formation branch concentration of catalyst ink is preferably adjusted in the scope of 7 weight %～20 weight %, adjusts in the scope particularly preferably in 12 weight %～17 weight %.In catalyst ink, just can not mix and have each dope layer, and can obtain high-quality MEA.
The manufacture method of catalyst ink for example uses following method to get final product.
At first, with catalyst, divide mixing under the high state of concentration solid formation as the solvent of at least 1 composition of employed solvent in the catalyst ink.Be the operation that is called as what is called " the high solid branch concentration mixing (doing thick mixing) that forms ", can adjust the dispersiveness of the catalyst in the catalyst ink.
As employed mixing machine in the described dried thick mixing operation, for example can use planetary-type mixer etc.
Then, add as the solvent of at least 1 composition of described solvent and dilute, further mixing.Thereafter, dilute repeatedly as required and mixing, the catalyst ink that finally forms essential solid formation branch concentration gets final product.Binding agent, have hydrogen resin etc. so long as described do thick mixing operation and finish after, just can add where necessary.
When use has supported the carbon dust of noble metal as catalyst, also can make resin in advance attached on the carbon dust with hydrogen.Make described resin attached to carbon dust on the time, for example use Henschel mixer etc. to get final product.
And the mixing machine as use this moment except described planetary-type mixer, can use screw mixer, the strange mixer of Airy etc.
At this moment, preferably include with catalyst, as the solvent of at least 1 composition of described solvent operation at ratio mixing under the state more than the 20 weight % of catalyst.Wherein, do in the thick mixing operation described, preferably the ratio of catalyst is the above states of 20 weight %.Owing to form admittedly under the branch concentration at height and to mix, so the dispersiveness of the catalyst in the catalyst ink will improve, thereby can reduce the viscosity of the catalyst ink in the shear rate zone.Thus, when when using, the flowability of the catalyst ink layer after the coating will become greatly as catalyst ink (particularly as being coated on catalyst ink on the polyelectrolyte layers), thus the generation of the be full of cracks can further suppress catalyst layer formation the time.
In addition, in the operation of mixing under the described state of ratio more than 20 weight % at catalyst, with the solvent of catalyst mix preferably in the middle of the composition of described solvent with the highest solvent of described catalyst compatibility.Here, so-called " solvent that compatibility is the highest " is meant the solvent that described catalyst is disperseed.
As base material, can use by the resin film of PETG (PET), polypropylene (PP), polyethylene (PE), Merlon formations such as (PC) or to its surface and carry out the material of handling.In addition, also can using gases infiltration type collector body.The scope of the preferred 50 μ m of the thickness of base material～150 μ m.
As apparatus for coating, for example can use chill coating machine, intaglio plate coating machine, reverse roll coating machine etc.The scope of the preferred 10 μ m of the thickness of the polyelectrolyte dope layer after the coating～30 μ m, the scope of the preferred 3 μ m of the thickness of the catalyst ink layer after the coating～100 μ m.
In addition, in addition,, for example also can use the method for in No. 2842347 communique of patent or No. 3162026 communique of patent etc., being announced as the method for coating.
Each dope layer that is layered on the base material 1001 shown in Figure 4, device 1054 dryings that are dried form and have comprised catalyst layer stacked and the MEA of the structure of polyelectrolyte layers.At this moment, as the mode of drying, can use hot blast mode, far infrared mode etc.Though baking temperature changes according to employed solvent composition in each coating, preferred 60 ℃～80 ℃ scope.
And, as required, both can the different a plurality of drying devices of design temperature, also can omit drying device.
Fig. 6 is the schematic diagram that expression utilizes the example of the MEA that the manufacture method of MEA of the present invention makes.On the base material 1001 of band shape, be laminated with catalyst layer 1022, polyelectrolyte layers 1032 and catalyst layer 1042.And, in the example shown in Figure 6, also be not processed into the shape in the actual battery of packing into, also need removing of base material to process thereafter with shape.Here, the width W of catalyst layer 1022 1, polyelectrolyte layers 1032 width W 2And the width W of catalyst layer 1042 3Preferably satisfy W 1≤ W 2And W 3≤ W 2Relation.The width of each layer can be adjusted when each coating of coating.
In addition, if for example with catalyst layer 1022 and catalyst layer 1042 according to the mode coating composition that mutual outer rim is roughly overlapped, then add man-hour in shapes such as carrying out stamping-out thereafter, if making the shape of its shape and catalyst layer coincide, then can prevent to contain the loss of the catalyst layer of expensive noble metal widely, thereby can reduce the manufacturing cost of fuel cell.
The profile of representing the A-A direction of MEA shown in Figure 6 among Fig. 7.The length L of the catalyst layer 1022 on the transfer direction of base material 1001 1, base material 1001 transfer direction on the length L of polyelectrolyte layers 1032 2And the length L of the catalyst layer 1042 on the transfer direction of base material 1001 3Preferably satisfy L 1≤ L 2And L 3≤ L 2 Relation.Catalyst layer 1022 just is difficult to contact after stacked with catalyst layer 1042, thereby it is bad etc. to suppress the electric leakage of MEA of gained.The length of each layer can be adjusted when each coating of coating.
In addition, as Figure 6 and Figure 7, polyelectrolyte layers 1032 preferably wraps into catalyst layer 1022.Can obtain further to have suppressed the bad MEA that leaks electricity.Its shape can obtain by the coating time of regulating each coating.
And in the example shown in Fig. 6, ground forms continuously though polyelectrolyte layers 1032 is become band, also can with catalyst layer 1022 or catalyst layer 1042 in the same manner, formed off and on.At this moment, as long as be formed on the shape that to generate electricity in the actual battery.In addition,, also MEA can be made in advance the shape of the battery of packing into, at this moment, can omit the operation of shape processing by regulating the coating time of each coating.
In addition,, also can utilize the composition change of coating etc., form the intermediate layer at the interlayer of catalyst layer 1022 and polyelectrolyte layers 1032 and/or at the interlayer of catalyst layer 1042 and polyelectrolyte layers 1032.Can improve the cementability of interlayer, the adhesive strength on the interface of each layer that constitutes MEA is further increased, thus can the more good high MEA of reliability of acquired character.When the high MEA of the reliability that this specific character is good packs battery into, just can obtain the fuel cell that the discharge rate of battery or life characteristic have further improved.
(execution mode 3)
Fig. 8 is the operation schematic diagram of an example of expression MEA manufacture method of the present invention.In the example shown in Figure 8, banded base material 1101 is transferred continuously, is coated with catalyst ink 1102, polyelectrolyte coating 1103 and catalyst ink 1104 on base material 1101 successively.The coating of catalyst ink 1102, polyelectrolyte coating 1103 and catalyst ink 1104 utilizes apparatus for coating 1151,1152 and 1153 to carry out respectively.
Each coating that is coated with becomes catalyst ink layer 1121,1141 and polyelectrolyte dope layer 1131, after the drying of utilizing drying device 1154 to carry out, if remove base material 1101, then can obtain catalyst layer 1122 stacked, the MEA of polyelectrolyte layers 1132, catalyst layer 1142.
Here, as long as polyelectrolyte coating 1103 contains gelating agent.By containing gelating agent, just can suppress the flowability of polyelectrolyte dope layer 1131, thereby the be full of cracks can further suppress catalyst layer 1142 and form the time produces.
The ratio that 33 weight % of the preferred polyelectrolyte coating of gelating agent are following.In this scope, can suppress deterioration as the hydrogen ion transport properties of polyelectrolyte layers.In addition, the scope of wherein preferred 5 weight %～33 weight %.
As gelating agent, preferred thermal sensitivity gelating agent.So-called thermal sensitivity gelating agent is meant when reaching the material that specific temperature province can play a role as gelating agent when above.Thus, if use the thermal sensitivity gelating agent that in carrying out dry temperature province, begins to play a role as gelating agent, then can when the coating of polyelectrolyte coating 1103, keep coating flowability (, be coated with easily), thus can be in the flowability that is considered to suppress when meeting produces the heat drying of be full of cracks in catalyst layer 1142 polyelectrolyte dope layer 1131.
As the thermal sensitivity gelating agent, for example can be in the gelating agent of styrene butadiene rubbers class, use its gelling temperature at gelating agent of 40 ℃～70 ℃ of scopes etc.
When polyelectrolyte coating contained gelating agent, the polyelectrolyte layers of the MEA of coating, dry back gained just had the feature of porous.Though its average pore size is different because of the material of polyelectrolyte coating, employed gelating agent etc., owing to for example be the scope about 0.1 μ m～1.0 μ m, and is separate wells, so can suppresses the generation of gas leakage etc.
And polyelectrolyte coating 1103 can also contain described thickener.At this moment, with respect to polyelectrolyte coating, be preferably in below the 10 weight %.
In addition, in the example shown in Figure 8, identical with example shown in Figure 4, though painting catalyst dope layer 1141 before polyelectrolyte dope layer 1131 dryings, but in polyelectrolyte coating, contain under the situation of gelating agent, also can be after having formed polyelectrolyte layers making the polyelectrolyte dry paint layer, painting catalyst coating.
As mentioned above, when going up direct painting catalyst coating at polyelectrolyte layers (promptly equal) with polyelectrolyte membrane, the mechanical strength of polyelectrolyte membrane is generally less, polyelectrolyte membrane dissolves because of solvent composition contained in the catalyst ink or expands, and has problems in these areas.
But, if in polyelectrolyte coating, contain gelating agent, then after drying, when having formed polyelectrolyte layers, just can improve intensity, the dissolving that can suppress in addition to cause, expansion etc. by solvent composition contained in the catalyst ink.Thus, just can the good high MEA of reliability of acquired character.In addition, not only be pre-formed polyelectrolyte layers, and in its two sided coatings catalyst ink etc., thereby can under the state that keeps characteristic, reliability, can also have increased the variation of the manufacture method of MEA as MEA.
And, in the example shown in Figure 8, for the base material beyond the polyelectrolyte coating 1103, catalyst ink, apparatus for coating, drying device etc., can use with execution mode 2 in employed identical materials or device.
(execution mode 4)
Fig. 9 is the schematic diagram of the configuration example of expression fuel-cell single-cell of the present invention unit, and the single cell units with the formation shown in the figure can utilize the manufacture method of general fuel cell to obtain.
For example, the two sides of the MEA1231 of Huo Deing disposes gas diffusion layers 1232 and 1233 in said embodiment.Then, on MEA1231, configuration is used to the liner that prevents the intrusion of cooling water or be used to prevent the leakage of reacting gas, forms the tap that cooling water and reacting gas are used., the barrier film 1234 and 1235 that on the whole formed the stream of reacting gas according to described stream mode in the face of gas diffusion layers 1232 and 1233 disposed, integral body is engaged just can obtain the fuel-cell single-cell unit thereafter.Side in the middle of the barrier film 1234 and 1235 becomes the anode barrier film, and the opposing party becomes cathode diaphragm.In addition, if the single cell units that will obtain as mentioned above is stacked a plurality of, just can obtain fuel cell stack.
As gas diffusion layers, so long as have conductivity and get final product for the material of reacting gas permeability.For example, can use carbon paper, carbon cloth etc.Also can utilize polytetrafluoroethylene etc. to carry out hydrophobic processing as required.
As liner, can use rubber, silicon etc.
As barrier film, so long as the material that has conductivity and have an essential mechanical strength gets final product.For example, can use the graphite cake that flooded phenolic resins, expandable graphite, metallic plate that resistance to oxidation handles etc. has been implemented on the surface.
To utilize embodiment that the present invention is further elaborated below.
(embodiment 1)
In the present embodiment,, prepare to contain the sample (9 kinds) of the organic solvent shown in the table 1, made MEA respectively, its characteristic is estimated as the solvent of catalyst ink.Ethanol in the middle of the described organic solvent is employed solvent in the past.
In the carbon dust that has supported 50 weight % platinum (Tanaka's noble metal industry (strain) system TEC10E50E) 100g, add ion exchange water 233g, the planetary-type mixer of use capacity 20L (special machineization (strain) system HIVIS MIX) has carried out dried thick mixing as the initial mixing operation of catalyst ink production process.The solid formation branch concentration of this moment is 30 weight %, and the rotary speed of planetary-type mixer is made as 40rpm, has carried out 90 minutes processing.
Then, divide the equivalent input 2 times with organic solvent 23g shown in the table 1 and 1-propyl alcohol 55g, each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, carried out 10 minutes mixings and handled.By the 2nd time input, reach 24.3 weight % Gu form branch concentration.
Then, 197g divides the equivalent input four times with polyelectrolyte dispersion liquid (23.5 weight % dispersion liquids of perfluoroethylene sulfonic acid), and each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, and the mixing that has carried out 10 minutes is handled.And the dispersant of polyelectrolyte dispersion liquid is the mixed solvent of water/ethanol/1-propyl alcohol, and its weight mixing ratio is 22 weight %/18 weight %/60 weight %.
Then, reach 15 weight % until solid the branchs concentration that forms, divide the equivalent input 3 times with the organic solvent 353g shown in the table 1, each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, carried out 10 minutes mixing processing.
Thereafter, divide the equivalent input 2 times with the organic solvent 174g shown in water 3g and the table 1, after the input each time all is made as 50rpm with the rotary speed of planetary-type mixer, the mixing that has carried out 10 minutes is handled, the cathod catalyst coating (weight ratio of the described organic solvent in the solvent is 60 weight %) that to have made solid formation branch concentration be 12 weight %.
In addition, as organic solvent, organic solvent shown in the replacement table 1 and use ethanol, as catalyst, use has supported the carbon dust of 30 weight % platinum, 15 weight % rutheniums on Kai Qihei (ketjen black) (45 weight %), use and made anode catalyst coating with described identical method.
As polyelectrolyte coating, with described polyelectrolyte dispersion liquid (23.5 weight % dispersion liquids of perfluoroethylene sulfonic acid), cathod catalyst coating of Zhun Beiing and anode catalyst coating as mentioned above, use the chill coating machine, make by PETG the surface is implemented base material (Japan METALLIZING corporate system CELLAPEEL SW thickness: 50 μ m), begin with anode catalyst dope layer (thickness 15 μ m) of handling of the demoulding from the base material side, polyelectrolyte dope layer (thickness 30 μ m), the order of cathod catalyst dope layer (thickness 20 μ m) is coated with.The interval of the coating of each dope layer promptly, was made as 5 seconds up to the time of the next dope layer of coating on this dope layer after the coating of any one dope layer.
At this moment, for the polyelectrolyte dope layer, carry out the width (W that is equivalent to Fig. 6 2) the continuous brushing of 130mm, for two catalyst ink layers, carried out intermittently brushing with the rectangular shape of regarding 70mm * 70mm from the stromatolith direction as.According to making anode catalyst dope layer and cathod catalyst dope layer from the stromatolith direction, the mode that roughly overlaps of its outer rim is brushed each other, and the interval of the brushing at intermittence of catalyst ink layer is made as 65mm.And the translational speed of the base material during brushing is 1.5m/ minute.
Thereafter, the drying of utilizing adverse current hot blast mode to carry out 2 minutes has obtained being laminated in the MEA of the state on the base material.At this moment, be 80 ℃ according to making the coated face temperature, the wind speed of the hot blast of coated face reaches the mode of 3.0m/s and sets.
For as the generation of the be full of cracks of the cathod catalyst laminar surface of the superiors of the MEA of acquisition as mentioned above, implemented to utilize the picture appraisal of binaryzation method, carried out the evaluation of the occupation rate of be full of cracks part.The value of having used ethanol as the sample of described organic solvent is made as 100, the relative value of the be full of cracks occupation rate of each sample is illustrated in the following table 1.
The MEA that will obtain as mentioned above cut out cut after, in 100 ℃ ion exchange water, flooded 1 hour after, carry out 80 ℃ of heated-air dryings of 30 minutes, removed residual solvent.Use the MEA that so obtains to generate electricity practically, estimated its power generation characteristics.
At first, the part that only will be laminated with polyelectrolyte layers from the MEA that is laminated in the state on the base material is cut out and is cut, removes, and thereafter base material is removed, and has obtained the MEA sample of the size of 120mm * 120mm.
On the other hand, with the following preparation of gas diffusion layers.The aqueous liquid dispersion of acetylene black and polytetrafluoroethylene is mixed, modulated the hydrophobic black liquid that contains 20 weight % polytetrafluoroethylene with the dry weight conversion.This hydrophobic black liquid coating is immersed on the carbon paper of the skeleton that becomes gas diffusion layers, and the use air drier is heat-treated under 300 ℃, has formed to have hydrophobic gas diffusion layers.
Described gas diffusion layers fitted according to the mode that contacts with two catalyst layer surface of described MEA and make electrode, engage the lining plank of rubber system, formed the general tap of cooling water and reacting gas flow at the peripheral part of described electrode.
Then, the diaphragm plate that preparation is made by the graphite cake that has flooded phenolic resins (has formed the stream of fuel gas on 1, formed the plate of the stream of oxidant gas on 1 at other) 2 slices, make it to overlap and engage according to the mode that above-mentioned barrier film is contacted with described electrode (mode that contacts, makes the stream of oxidant gas to contact according to the stream that makes fuel gas with anode side electrode), made single cell units with formation shown in Figure 9 with the cathode side electrode.
After having made single cell units, supply with pure hydrogen to fuel electrodes respectively, to oxidation utmost point air supply, carry out the generator experimental of described single cell units, measured current density 0.2A/cm 2Under the initial stage discharge voltage at generating initial stage and generating beginning after through the discharge voltage after 1000 hours.At this moment, battery temperature is made as 75 ℃, with fuel gas utilance U fBe made as 70%, with oxidant gas utilance U oBe made as 40%, the dew point of fuel gas is made as 70 ℃, the dew point of oxidant gas is made as 50 ℃.
The result of the generator experimental of described single cell units is illustrated in the table 1.And when having used ethanol as organic solvent, the be full of cracks on cathod catalyst surface is very serious, is difficult to make single cell units.Thus, for the result of generator experimental, the relative value that the value when will use propylene glycol monomethyl ether as organic solvent (initial stage discharge voltage 0.74V, passed through discharge voltage 0.72V after 1000 hours) was made as 100 o'clock is represented.
The solvent name Boiling point (℃) Saturated vapor pressure under 20 ℃ (mmHg) Catalyst layer be full of cracks occupation rate (%) Initial stage discharge voltage (relative value) (%) Discharge voltage after 5000 hours (relative value) (%)
Ethanol (example in the past) 78 45 - - -
Propylene glycol monomethyl ether 121 8 70 100 100
Dipropylene glycol monomethyl ether 189 ＜0.1 60 103 101
The tripropylene glycol monomethyl ether 243 0.02 10 110 109
Propylene glycol-n-propyl ether 150 1.5 50 104 105
DPG-n 212 0.08 10 110 111
-propyl ether
Propylene glycol-n-butyl ether 170 0.85 10 109 110
DPG-n-butyl ether 229 0.04 10 111 109
PGDA 190 ＜0.1 75 98 97
As shown in table 1, when solvent as catalyst ink, used and contained 1 boiling point under the atmospheric pressure when (being 60 weight % in the present embodiment) solvent of the organic solvent more than 120 ℃, the be full of cracks occupation rate that is layered in the cathode catalyst layer on the polyelectrolyte layers reduces.In addition,, be difficult to make single cell units, on the contrary, can generate electricity no problemly with in having used the example in the past of ethanol.
In addition, similarly, when solvent as catalyst ink, when having used the saturated steam that contains under 20 ℃ to be pressed in (being 60 weight % in the present embodiment) solvent of the following organic solvent of 1.06kPa (8mmHg), the be full of cracks occupation rate that is layered in the cathode catalyst layer on the polyelectrolyte layers reduces.
Wherein, when the solvent of catalyst ink contains saturated steam under 20 ℃ and is pressed in organic solvent (being 60 weight % in the present embodiment) below the 0.20kPa (1.5mmHg), under the situation that contains the organic solvent of representing with described general formula (A), battery behaviors such as discharge rate or life-span particularly improve.
(embodiment 2)
In the present embodiment, use the method identical, carried out the test of the weight rate of the described organic solvent in the change cathod catalyst coating with embodiment 1.And, in described organic solvent, used propylene glycol-n-butyl ether.
At first, the following cathod catalyst coating of weight rate below 40 weight % of having made the described organic solvent in the catalyst ink.
In carbon dust (Tanaka's noble metal industry (strain) system TEC10E50E) 100g of the platinum that has supported 50 weight %, add ion exchange water 233g, the planetary-type mixer of use capacity 20L (special machineization (strain) system HIVIS MIX) has carried out dried thick mixing as the initial mixing operation of catalyst ink production process.The solid formation branch concentration of this moment is 30 weight %, and the rotary speed of planetary-type mixer is made as 40rpm, has carried out 90 minutes processing.
Then, divide the equivalent input 2 times with propylene glycol-n-butyl ether 23g and 1-propyl alcohol 55g, each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, carried out 10 minutes mixings and handled.
Then, 197g divides the equivalent input four times with polyelectrolyte dispersion liquid (23.5 weight % dispersion liquids of perfluoroethylene sulfonic acid), and each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, and the mixing that has carried out 10 minutes is handled.And the dispersant of polyelectrolyte dispersion liquid is the mixed solvent of water/ethanol/1-propyl alcohol, and its weight mixing ratio is 22 weight %/18 weight %/60 weight %.
Then, divide the equivalent input 2 times with propylene glycol-n-butyl ether 235g, each after the input time all is made as 50rpm with the rotary speed of planetary-type mixer, carried out 10 minutes processing.Then, drop into propylene glycol-n-butyl ether 89g, the rotary speed of planetary-type mixer is made as 50rpm, the mixing that has carried out 10 minutes is handled.
Thereafter, divide the equivalent input 2 times with water 205g and propylene glycol-n-butyl ether 82g, after the input each time all is made as 50rpm with the rotary speed of planetary-type mixer, the mixing that has carried out 10 minutes is handled, the cathod catalyst coating (weight ratio of the propylene glycol in the solvent-n-butyl ether is 40 weight %) that to have made solid formation branch concentration be 12 weight %.
Then, the following weight rate of having made the described organic solvent in the catalyst ink cathod catalyst coating that is 30 weight %.
Handling up to the input of polyelectrolyte dispersion liquid, the mixing that utilizes planetary-type mixer to carry out, all with after described identical order is carried out, drop into propylene glycol-n-butyl ether 118g, the rotary speed of planetary-type mixer is made as 50rpm, the mixing that has carried out 10 minutes is handled.
Thereafter, drop into propylene glycol-n-butyl ether 107g again, the rotary speed of planetary-type mixer is made as 50rpm, the mixing that has carried out 10 minutes is handled.Then, divide the equivalent input 2 times with water 312g and propylene glycol-n-butyl ether 74g, after the input each time all is made as 50rpm with the rotary speed of planetary-type mixer, the mixing that has carried out 10 minutes is handled, the cathod catalyst coating (weight ratio of the propylene glycol in the solvent-n-butyl ether is 30 weight %) that to have made solid formation branch concentration be 12 weight %.
Then, the following weight rate of having made the described organic solvent in the catalyst ink cathod catalyst coating that is 35 weight %.
Handling up to the input of polyelectrolyte dispersion liquid, the mixing that utilizes planetary-type mixer to carry out, all with after described identical order is carried out, with propylene glycol-n-butyl ether 235g equivalent input at twice, after the input each time all is made as 50rpm with the rotary speed of planetary-type mixer, and the mixing that has carried out 10 minutes is handled.
Thereafter, divide the equivalent input 2 times with water 259g, propylene glycol-n-butyl ether 118g again, after the input each time all is made as 50rpm with the rotary speed of planetary-type mixer, the mixing that has carried out 10 minutes is handled, the cathod catalyst coating (weight ratio of the propylene glycol in the solvent-n-butyl ether is 35 weight %) that to have made solid formation branch concentration be 12 weight %.
Use the cathod catalyst coating of making as mentioned above, with embodiment 1 in the same manner, the battery behavior when be full of cracks occupation rate that produces in cathode catalyst layer when making MEA and the MEA that uses gained make single cell units is estimated.Comprise result's (weight ratio of the propylene glycol in the solvent-n-butyl ether is 60 weight %) of embodiment 1, described evaluating characteristics result is illustrated in the table 2.
(table 2)
The ratio of organic solvent (%) Catalyst layer be full of cracks occupation rate (%) Initial stage discharge voltage (relative value) (%) Discharge voltage after 5000 hours (relative value) (%)
60 10 109 110
40 50 105 105
35 75 99 99
30 80 98 97
As shown in table 2, at solvent as catalyst ink, used to contain more than the 40 weight % under the situation of saturated vapor pressure under 20 ℃ as (propylene glycol n-butyl ether) solvent of the following organic solvent of 1.06kPa (8mmHg), the be full of cracks occupation rate that is layered in the cathode catalyst layer on the polyelectrolyte layers reduces, and battery behavior improves.
(embodiment 3)
The solvent as catalyst ink for embodiment 2 has used the cathod catalyst coating that contains the solvent of propylene glycol-n-butyl ether with 40 weight %, when carrying out as the initial mixing operation of catalyst ink production process dried thick mixing, made and to have formed the catalyst ink that branch concentration is made as 20 weight % and 17 weight % admittedly, carried out the evaluation identical with embodiment 1.
Gu formation branch concentration is the cathod catalyst coating of 20 weight % is by when doing thick mixing, in the carbon dust that has supported 50 weight % platinum (Tanaka's noble metal industry (strain) system TEC10E50E) 100g, adds ion exchange water 400g and make.The weight ratio of the propylene glycol-n-butyl ether in the solvent of other operation and embodiment 2 is that the cathod catalyst coating of the 40 weight % method of making is identical.But,, replace " with water 312g and propylene glycol-n-butyl ether 84g equivalent input at twice " for the last input in the middle of the method shown in the embodiment 2, change to " with water 54g and propylene glycol-n-butyl ether 93g equivalent input at twice ".
In addition, Gu formation branch concentration is the cathod catalyst coating of 17 weight % is by when doing thick mixing similarly, in the carbon dust that has supported 50 weight % platinum (Tanaka's noble metal industry (strain) system TEC10E50E) 100g, adds ion exchange water 488g and make.Here,, also replace " with water 312g and propylene glycol-n-butyl ether 84g equivalent input at twice " for the last input in the middle of the method shown in the embodiment 2, change to " with propylene glycol-n-butyl ether 59g equivalent input at twice ".
Use the cathod catalyst coating of making as mentioned above, with embodiment 1 in the same manner, the battery behavior when be full of cracks occupation rate that produces in cathode catalyst layer when making MEA and the MEA that uses gained make single cell units is estimated.Comprise result's (weight ratio of the propylene glycol in the solvent-n-butyl ether is 30 weight %) of embodiment 1, described evaluating characteristics result is illustrated in the table 3.
In addition, measured shear viscosity respectively for the cathod catalyst coating of making as mentioned above, tried to achieve with present embodiment in the ratio of shear viscosity of the polyelectrolyte coating (23.5 weight % dispersion liquids of perfluoroethylene sulfonic acid) that uses.Shear viscosity be under 25 ℃, shear rate 1s -1Utilize COMPLATE type viscosity apparatus (Rheometoric Scientific corporate system RFSII) to measure down.The shear viscosity of described polyelectrolyte coating is 0.7Pas.
Described shear viscosity is than being that the shear viscosity measured value of cathod catalyst coating and the shear viscosity measured value of polyelectrolyte coating are compared, and value that will a bigger side is removed with a less side's value and the numerical value that obtains (following be B value) shows.And, in the present embodiment, all be that a side of the shear viscosity of cathod catalyst coating is bigger value.
The B value combined statement of each cathod catalyst coating of trying to achieve as mentioned above is shown in the table 3.
(table 3)
Divide concentration (%) Gu form The B value Catalyst layer be full of cracks occupation rate (%) Initial stage discharge voltage (relative value) (%) Discharge voltage after 5000 hours (relative value) (%)
30 21 50 105 105
20 25 52 104 104
17 40 65 100 100
As shown in table 3, used the generation that more can suppress the be full of cracks of cathode catalyst layer with a solid side who forms the MEA that has carried out doing thick mixing cathod catalyst coating more than the branchs concentration 20 weight %, battery behavior is further raising also.In addition, do thick solid formation when mixing and divide concentration big more, then the dispersiveness of catalyst will improve, and the viscosity of the catalyst ink under the low shearing speed will descend, and diminishes with the ratio of viscosities of polyelectrolyte coating.As shown in table 3, under the situation below 25, can suppress the generation of the be full of cracks of cathode catalyst layer, the battery behavior raising in the B value of the ratio of viscosities of expression catalyst ink and polyelectrolyte coating.
(embodiment 4)
In the present embodiment,,, make the test of the viscosity variation of polyelectrolyte coating by in polyelectrolyte coating, adding thickener in order to carry out the further research of described B value.
As thickener, prepared to contain 5 weight % or 7 weight % the degree of polymerization 2000 polyvinyl alcohol or contain 4 kinds of polyelectrolyte coating of polyvinyl alcohol of the degree of polymerization 200 of 10 weight % or 13 weight %.The base material of polyelectrolyte coating is 23.5 weight % dispersion liquids of the perfluoroethylene sulfonic acid that uses among the described embodiment.And the basicity of employed polyvinyl alcohol all is the scope of 98.0mol%～99.0mol%.
In cathod catalyst coating, use use among the embodiment 1 contain the catalyst ink of propylene glycol-n-butyl ether with 40 weight % as solvent, identical with embodiment 3, cathode catalyst layer be full of cracks occupation rate, the battery behavior when packing single cell units into and B value when MEA is made have been estimated characteristic.Its result is merged with the situation that does not contain thickener, be illustrated in the table 4.And, the shear viscosity of symbol "+" the expression cathod catalyst coating shown in the B value of table 4 is greater than the situation of the shear viscosity of polyelectrolyte coating, and the shear viscosity of "-" expression cathod catalyst coating is less than the situation of the shear viscosity of polyelectrolyte coating.
(table 4)
Thickener viscosity Thickener contains ratio (%) The B value Catalyst layer be full of cracks occupation rate (%) Initial stage discharge voltage (relative value) (%) Discharge voltage after 5000 hours (relative value) (%)
2000 10 1.2+ 10 110 110
2000 13 1.2- 8 110 111
200 33 0.9- 8 105 105
200 35 1.2- 7 90 92
- 0 21+ 50 105 105
As shown in table 4, because of polyelectrolyte coating contains thickener, the viscosity of the polyelectrolyte coating in the low shearing speed zone rises, and diminishes with the difference of the viscosity of the cathod catalyst coating in identical zone.At this moment, (i.e. Gui Lie generation suppressed significantly) MEA of having reduced significantly of the be full of cracks occupation rate that just can obtain cathode catalyst layer.
In addition, when observing B value, can find that the inhibition effect of be full of cracks generation that relatively becomes the bigger side's target catalyst layer of the viscosity of polyelectrolyte coating of lower floor is bigger.
In addition,, find that containing ratio when thickener is made as 33 weight % when following, just can obtain not add the characteristic more than the situation of thickener about battery behavior.When increasing the amount of the thickener that is added, though play the effect that battery behavior is improved because of the be full of cracks of cathode catalyst layer produces to be suppressed, but simultaneously, the thickener composition that does not have hydrogen in polyelectrolyte layers increases, thereby infers the effect that battery behavior is reduced.
(embodiment 5)
In the present embodiment, carried out in polyelectrolyte coating, having added the test of the situation of gelating agent.
As gelating agent, be the thermal sensitivity gelating agent, used heat-sensitive gel voltinism latex (Sanyo changes into the industry system).When with this material heating, will be from the aqueous gel that is changed in the scope of 55 ℃～75 ℃ of temperature.In the present embodiment, the polyelectrolyte coating of the nonvolatile component that contains 5 weight %, 7 weight %, 30 weight %, 33 weight % heat-sensitive gel voltinism latexes is studied.And, in the polyelectrolyte coating of base material, used 24% dispersion liquid of the perfluoroethylene sulfonic acid that uses among the described embodiment.
In cathod catalyst coating, use use among the embodiment 1 contain the catalyst ink of 40 weight % propylene glycol-n-butyl ether as solvent, identical with embodiment 1, the cathode catalyst layer be full of cracks occupation rate when MEA is made, the battery behavior when packing single cell units into are estimated.Its result is merged with the situation that does not contain gelating agent, be illustrated in the table 5.
(table 5)
The thermal sensitivity gelating agent contains ratio (%) Catalyst layer be full of cracks occupation rate (%) Initial stage discharge voltage (relative value) (%) Discharge voltage after 5000 hours (relative value) (%)
0 50 105 105
5 11 111 110
7 9 110 110
33 8 105 105
35 7 90 92
As shown in table 5, by containing gelating agent at polyelectrolyte coating, the MEA that the be full of cracks occupation rate that just can obtain cathode catalyst layer has reduced significantly.This is because because polyelectrolyte coating gelation before the solvent evaporation of cathod catalyst coating, so the contraction of polyelectrolyte dope layer moves and be suppressed, and as a result of, just can suppress the generation of the be full of cracks in the cathode catalyst layer.
Find that in addition under the situation below the 33 weight %, battery behavior further improves at the containing ratio of gelating agent.Identical with the thickener of embodiment 4, when increasing the amount of the gelating agent that is added, though play the effect that battery behavior is improved because of the be full of cracks of cathode catalyst layer produces to be suppressed, but simultaneously, do not increase owing in polyelectrolyte layers, do not have the gelating agent composition of hydrogen, thereby we can say below the preferred 33 weight % of containing ratio of gelating agent.
The industrial possibility of utilizing
Can see that from above explanation the present invention can provide the manufacture method of the fuel battery membrane electrode assembly that the productivity that makes fuel cell and performance significantly improve, manufacturing installation and the membrane-electrode assembly of fuel battery membrane electrode assembly.
In addition, the present invention can provide the manufacture method of the high fuel battery membrane electrode assembly of productivity and the manufacturing installation of fuel battery membrane electrode assembly.
In addition, the present invention can provide the coating that does not have dielectric substrate to enter in the space that is formed in the first catalyst layer and make the manufacture method of fuel battery membrane electrode assembly of situation of electrical property variation and the manufacturing installation of fuel battery membrane electrode assembly.
In addition, even the coating that the present invention can provide the coating that will become electrolytical raw material and become the raw material of the second coating is coated with simultaneously, the manufacture method of the fuel battery membrane electrode assembly that electrical property can variation yet and the manufacturing installation of fuel battery membrane electrode assembly.
In addition, the present invention can provide the lower membrane-electrode assembly of internal resistance of membrane-electrode assembly compared with the past.
In addition, the present invention can be provided for obtaining the manufacture method of the stable fuel battery membrane electrode assembly of the less power generation characteristics of constructional defective such as separating between be full of cracks, catalyst layer and the polyelectrolyte layers of catalyst layer. In addition, the fuel battery membrane electrode assembly by use utilizes described manufacture method to make just can obtain the good fuel cell of battery behavior. The polyelectrolyte coating of the fuel cell that in addition, can obtain to realize that described battery behavior is good.

Claims (5)

1. the manufacture method of a fuel battery membrane electrode assembly is characterized in that, possesses:
On the base material that moves, by be coated with the 1st catalyst layer that the 1st coating forms the 1st catalyst layer form operation,
During being in wet condition at described the 1st catalyst layer, the 2nd coating is coated on described the 1st catalyst layer and the electrolyte that forms dielectric substrate form operation,
Make described dielectric substrate according to the thickness that is held wet condition reach the mode drying of specific thickness drying process,
Form operation by the 3rd coating being coated on the 2nd catalyst layer that forms the 2nd catalyst layer on the described dielectric substrate that has been dried,
Described the 1st catalyst layer and described the 2nd catalyst layer are respectively the hydrogen utmost point and the oxygen utmost point, perhaps are respectively the oxygen utmost point and the hydrogen utmost point.
2. the manufacture method of fuel battery membrane electrode assembly according to claim 1 is characterized in that, the baking temperature of described drying process is in the scope below 150 ℃ more than 20 ℃.
3. the manufacture method of fuel battery membrane electrode assembly according to claim 1 and 2 is characterized in that, in described drying process, in the scope of the distance of hot-blast outlet portion and described dielectric substrate below the above 500mm of 10mm.
4. the manufacture method of fuel battery membrane electrode assembly according to claim 3 is characterized in that, in described drying process, in the scope of flow velocity below the above 20m of per second 1m of the hot blast of the position of the described hot-blast outlet 10mm of portion of distance.
5. fuel battery membrane electrode assembly is characterized in that possessing: the hydrogen utmost point, be formed at dielectric substrate that described hydrogen extremely goes up, be formed at the oxygen utmost point on the described dielectric substrate, the described oxygen utmost point is compared with the described hydrogen utmost point, and the area that contacts with described dielectric substrate is big.
CNA2006101542328A 2002-07-29 2003-07-28 Method for manufacturing membrane electrode assembly for fuel cell Withdrawn CN1996648A (en)

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