JPS6282664A - Electrode substrate for manifold mounted fuel cell and its manufacture - Google Patents

Abstract

PURPOSE:To join together a manifold with a separator by joining a manifold comprising a dense-carbon plate to the extended part of a separator through a fluorine resin layer. CONSTITUTION:An electrode substrate consists of two electrode 1 having a reaction gas passage 5, a separator 4 interposed between the electrodes 1, and a manifold 2 arranged in the periphery of electrode 1. The separator 4 largely extends outward from the periphery of the electrode 1, and the manifold 2 is joined to the extended part. A flexible graphite sheet is placed between the separator 4 and the electrode 1, and the extended periphery of the separator 4 and the manifold 2 are joined through fluorine resin. Thereby, the manifold 2 is joined together with the separator 4.

Description

[Detailed Description of the Invention] [Industrial Field of Application 1] The present invention generally relates to an electrode substrate for a phosphoric acid fuel cell;
More specifically, a porous carbonaceous electrode section provided with a reaction gas flow path is joined to both sides of a separator via a flexible graphite sheet, and the separator extends outward from the electrode section. A manifold part made of a gas-impermeable dense carbon plate provided with a passage for supplying a reactive gas to the extension part of the separator is bonded to the fuel cell electrode substrate J3 through a wood resin layer. The present invention relates to an electrode substrate for a fuel cell with a manifold, characterized by:

All the members of the "manifold f" fuel cell electrode substrate of the present invention are bonded with carbon or fluororesin, and are particularly resistant to phosphoric acid. (abbreviated) are joined into one body, which has a reinforcing effect and therefore has excellent handling properties.

"Prior Art" Generally, substrates used as electrodes in phosphoric acid fuel cells are stacked with one side in contact with a phosphoric acid matrix and the other side in contact with a separator.

In addition, in order to make a fuel cell by using a VI layer on the electrode substrate, a manifold for supplying reactive gas to the cell at the end of the electrode substrate must be installed, and at the same time, a fuel cell must be installed. The reaction gas is prevented from diffusing to the outside from the side of the ti VMu plate.

Conventionally, in such a fuel cell, the 1a connection between each member (
It was carried out using Bonzemen 1.

1 However, since carbon piment is oxidized by phosphoric acid, there is a possibility that parts may peel off or a reaction gas may leak through the joints.

Furthermore, since the electrode substrate is usually in the form of a thin plate, there is a problem in terms of mechanical strength that it may break during handling, especially if the substrate area is large.

[Problem of the Invention] An object of the present invention is to provide an electrode substrate for a manifold 4-stitched battery, in which a manifold portion provided with a reaction gas supply passage is joined and integrated with a separator.

Another object of the present invention is to provide an electrode substrate for a phosphoric acid fuel cell that has excellent resistance to phosphoric acid.

Further objects and advantages of the present invention will be apparent to those skilled in the art from the following description.

[Structure of the Invention J The present invention is characterized in that a porous carbonaceous electrode portion provided with a reaction gas flow path is joined to both sides of a separator via a flexible graphite sheet, and the separator is further away from the periphery of the electrode portion. In the fuel cell electrode substrate extending outward, a manifold part made of a gas-impermeable dense carbon plate provided with a reaction gas supply passage is joined to the extended part of the separator via a fluororesin layer. Is it characterized by being there? Provided is a fuel cell electrode plate 13 Jζ with two holds and a method for manufacturing the same.

[Detailed Description] Hereinafter, the electrode substrate of the present invention will be described in more detail with reference to the accompanying drawings.

′? Figure jS1 is a plan view of the electrode substrate of the present invention, and Figures 2 and 3 are cross-sectional views taken along lines n-yn and mm in Figure 1, respectively.

The electrode substrate of the present invention consists of two electrode parts 1 having reaction gas flow paths 5, a lever lever 4 located between the two electrode parts, and a manifold part 2 at the peripheral end of the electrode parts. The structure is right.

As shown in the figure, the separator 4 extends outward from the periphery of the electric current part 1, and the manifold part 2 is joined to this extended part.

A graphite sheet is interposed between the separator and the electrode part, and the peripheral end of the lever lever extending outward and the manifold part are respectively joined via fluororesin (Fig. 4). reference). Further, the manifold section 2 is provided with a reaction gas supply passage 3 that passes through the separator 4 including the separator 4. It is connected to the flow path 5.

The direction of flow of the reaction gas is indicated by arrows in FIGS. 2 and 3.

The reaction gas flow path 5 is defined by the gas diffusion part 6 and the rib part 7 in the electrode part 1, and the separator 4 or the flexible graphite sheet 1- (see FIG. 4, 30) joined to the separator 4.

The electrode part is made of porous carbonaceous material and has an average bulk density of 0.3 to -0.9 g/cc after firing at 1000°C or above.
, gas permeability 200M1/ Cri・hr -1111
It is preferable to have characteristics of 11 A 0 or more and an electrical resistance of 200 mΩ·cm or less.

Sepa 1 Noter has an average bulk density of 1.4 LJ/cc or more, a gas permeability of 10"d/, l -hr -111111
It is preferable to have an electrical resistance of 10 mΩ·C11l or more and a thickness of 2 mm or less.

There are many different internal structures of the manifold section, some examples of which are shown in FIG. The left diagram in FIG. 4 is a partial sectional view of the end portion, and the right diagram is a partial plan view of each.

In Figure 4 (1), the manifold part is 21.22 and 2.
The rib part 7 of the electrode part on one side of the lever is connected to the manifold part 2.
It has a structure that extends somewhat below 1 (for example, up to 7'). Moreover, the inner end of the manifold part 22 is 22
′ is indicated. These 21 and 222 are joined.

In Fig. 4, ■ indicates that the manifold parts 21 and 22 in (1) are integrally formed and are made into two parts, the manifold parts 21 and 23, and the rib part extends to the same surface 7' as the end surface of the gas diffusion part. There is. Note that the surface corresponding to the inner end 22' in (1) is indicated by 21'.

In FIG. 4 (J and (4)), the electrode section on one side of the separator extends to either end of the gas supply passage 3 (indicated by 1' in the figure), where the manifold section 21 It has a structure in which it touches the inner edge.

In either case, the manifold part b and the separator are joined via a fluororesin. Note that the structure shown in FIG. 4 is merely an example, and various structures different from that shown in FIG. 4 can be adopted depending on the purpose.

The above-mentioned 72 hold part has an average bulk density of 1.4(]/CC
At above, the gas permeability is 1O-4d/r:i-hr
-mmAq or less is preferable.

As already mentioned, although all the manifold parts and the lever regulator of the present invention are connected via fluororesin (in the case of the first base), it is possible to connect the battery to the outside through the manifold part, including the joint parts. The leakage time is expressed by the relationship [leak gas amount/(side length)/(differential pressure)], where the leakage gas per unit time per peripheral length of the joint under a constant differential pressure is 1O-2d101i-hr. -mmAq
Below/fit) f ma L, i.

The fluororesin used in the present invention is generally a fluororesin C with a melting point of 200°C or higher, and is particularly limited.
°C, 4.6K (If/ci heat distortion temperature 121 °C),
Edylene tetrafluoride-butylene hexafluoride [1-pyrene copolymer resin (
Abbreviation FEP, ia point 250-280'C.

4.6K (if10j heat distortion temperature 72℃), fluoroalkoxyethylene resin (abbreviation PFA, melting point 300-310
℃.

4.6 gf/crA heat distortion temperature 75℃), fluorinated ethylene propylene resin (abbreviation TFP, melting point 290~
300℃). These fluororesins are commercially available.

In d3 of the present invention, the above fluororesin is, for example, 50μ
It can be used as a sheet of about 601% ffi or as a dispersion of about 601% ffi. Small amounts of surfactants can be added to this dispersion.

To manufacture the electrode substrate for a manifold combustible FL battery of the present invention, a flexible graphite sheet is sandwiched between the electrode member and the separator material, and both sides of the sheet are bonded with an adhesive, and the temperature is further increased to about 1,000°C. The above is fired, and the extended portion of the separator material extending outward and the manifold member are joined by interposing a fluororesin sheet or ice version.

Note that hole 3 in the manifold section serves as a reaction gas supply passage.
can be opened at any stage during the process, such as before joining each manifold member to the separator material or at any stage during the process.
It can be opened by suitable means after being well-joined. Of course, a passage connecting this hole 3 and the reaction gas flow path 5 of the electrode member is provided as appropriate at the part where the manifold member is joined.'=j-T:
13 < is preferable.

The following materials are used as the electrode members of the electric vjAu plate of the present invention.

■ A hexacompound of short carbon fibers, a binder, and an organic particulate material is molded under heat and pressure (e.g., JP-A-59-6817
◇). In particular, short carbon fibers with a length of 2 mm or less 20 to 6
0 wt%, 20 to 50 Wj% of phenolic resin, and 20 to 50 wt% of organic particulate matter (pore control I) at a molding temperature of 100 to 180 °C and a molding pressure of 2 to 100 °C.
K (If/aA, molded under pressure holding time of 1 to 60 minutes.

(2) The molded member of [1] above is fired at 1,000°C or higher.

■ Carbon uA fibers with a length of 20 mm or less, pulp, regenerated cellulose fibers, and at least one type of i-fiber selected from polyacrylonite (heril), etc., are used as a papermaking binder (
A paper made by impregnating a mixed paper with a solution of phenolic resin (for example, see Japanese Patent Publication No. 18603/1983) is used as the gas diffusion part, and the raw material of [1] above is used. A molded product with a rib part formed using.

■ The molded product of [3] above is fired at 1,000°C or higher.

The separator material used in the present invention is 2.000℃
A dense carbon plate having a firing shrinkage rate of 0.2% or less when fired at is preferable.

Further, the manifold member is preferably a dense carbon material having a firing shrinkage rate of 0.2% or less when fired at 2,000°C.

A flexible V&V made by compressing expanded graphite particles used in the present invention
t/J Chuhin sheet is made by compressing expanded graphite particles obtained by acid treatment of graphite particles with a particle size of 5 mm or less and further heating, and has a thickness of +mm or less and a bulk density of 1. 0-1.
5 g/cc, compression strain rate, compression amount ffi I
Kg (distortion rate relative to /cni) is 0.35X 1O
-2ci/K (Jf or less, radius of curvature is 20m1
It is preferable to use a material that is flexible enough to not break even when bent up to 1, and a suitable example of a commercially available product is Graphoil (trade name) manufactured by UCC.

The adhesive used before each bonding when the above-mentioned electrode member and separator material are bonded via a flexible graphite sheet may be an adhesive normally used for bonding carbon materials.
Preferably, Si is a thermosetting resin selected from phenolic resin, EVO resin, and furan resin.

The thickness of this adhesive layer is not particularly limited, but
Generally, it is preferable to apply the coating uniformly with a thickness of 0.5 mm or more.

Furthermore, the bonding using the adhesive is performed at a temperature of 100° to 180°.
℃, press light - power 1, ! I-50K (l r /
It can be carried out within a range of 1 to 120 minutes between pressing sections.

As described above, the electrode member is bonded to the separator material via the flexible graphite sheet and fired at a temperature of about 1,000° C. or higher.

After that, a fluororesin sheet or dispersion is sandwiched or impregnated between the peripheral end of the separator material and the surface of the manifold member to be joined to it, and the 2KIN/c
The resin is bonded at a temperature of (melting point -50°C) or higher (melting point - 50°C) or higher when the frost melts at a pressure higher than M.

[Effect of the invention 1 Manifold part of the present invention obtained as described above 1
Since the manifold is integrally formed on the electric rod board for combustion batteries, once a reactive gas, etc. is introduced into the manifold, the necessary gases are supplied and discharged from the battery through the manifold parts of each member of the stacked battery. This will be possible as a holiday,
Normal MoF! Providing an external manifold for supplying and discharging reaction gases and the like required by the battery is of course not unnecessary, but has the following effects.

In other words, the Ti pole part and the valator are flexible graphite sheets 1
-, and since the manifold part and the separator are integrally bonded with a fluororesin, it has excellent phosphoric acid resistance and is particularly useful as an electrode substrate for phosphoric acid fuel cells. Also, since the manifold parts are evenly arranged and bonded around the flaky electrode substrate, this has a reinforcing effect, and as a result, the fuel... Excellent handling properties when producing 6 ponds.

[Examples] Hereinafter, the present invention will be explained in detail with reference to Examples, but the present invention is not limited to the following Examples.

Electrode part I Short carbon fiber (manufactured by Kenbetsu Kagaku Kogyo Co., Ltd., product name M-20)
48, flat EJf4 diameter 14m, average F28400μ5) 3
5%, phenolic resin (manufactured by Asahi Yokuzai Co., Ltd., product name R)
M-210) 30wt%, and polyvinyl alcohol particles (Nippon Gosei Kagaku Co., Ltd. special, average particle size 180-) 3
After mixing 5wt%, it is supplied to a predetermined mold, and the molding temperature is 13.
Molded at 5℃, molding pressure 35Kgf/ci, pressure holding time 20 minutes, 600mm (vertical) x 600m
A ribbed electrode member having a size of m (horizontal) x l and 5 mm (thickness) was manufactured. The flatness of the rib portion was 1.0 mm, and the thickness of the gas diffusion portion was 0.5 ml.

■ Separator material Showa Denko Co., Ltd.'s wI dense carbon root (thickness o, amm+) was cut to 720 mm lengthwise and widthwise, respectively, to make a separator material.

■ Manifold member manufactured by Tokai Carbon Co., Ltd. (7:!J density 1.85g/cc
, 1.5mm thick) dense carbon plate, length 60mm x width 720mm (4 pieces) 83 and length 60mm x E m
It was cut into pieces of 1600+ nm (4 pieces), and a portion corresponding to the reaction gas flow path of the electric 4G Jet board was cut to provide a gas flow path, thereby making a manifold member.

■ Teflon ■ A Teflon sheet (thickness 0.05 mm, manufactured by Nichias Co., Ltd.) was used.

■ Flexible graphite sheet Made by Graph Oil ■cucc, bulk density 1.10g/cc.

A piece (0.1 m thick) was cut appropriately according to the dimensions of the bonding surface and used.

A phenolic resin adhesive was applied to both sides of the Robeta material and one side of the graph oil, and then dried. then 1
Bonding was carried out under the conditions of 35°C, 10K (if/ci, 20 minutes).

Next, the adhesive was applied to the graph oil surface of the bonded product and dried. Similarly, the above adhesive was applied to the rib portion surface of the 1-distribution electrode member and dried. Then 135℃, 10K
(Bonded under the conditions of lf/cri, 20 minutes. After that, 2
,000°C.

Next, a Teflon sheet was sandwiched between the manifold member and the separator material. Then 360℃.

Melt pressure bonding was carried out at 50Kof10+f.

In order to measure the peel strength of the molten I@i, rl-attached surface, a test piece was adhered to a measuring jig with an epoxy adhesive and a tensile test was conducted. The peel strength was estimated to be 90 g f / cIi or more, since it did not peel off at the joint of Teflon Sea 1- but peeled off at the epoxy adhesive. This 9
The peel strength of 0 to 9r/ci or more is the peel strength of 3Kgr when ordinary carbon materials are bonded together with a thermosetting resin solution adhesive.
The adhesive strength is actually 30 times that of /Ci.

Instead of the Teflon sheet in Example 1, a Teflon ice version (manufactured by Mitsui Fluorochemical Co., Ltd.) was used.

PTFE (abbreviated as PTFE, aqueous solution containing 60% by volume) was applied evenly to the joint surface of the manifold member and the separator material, and dried in air. After that, 360℃, 50K
(Melting and crimping with Jf/ci.

The peel strength was the same as in Example 1.

[Brief explanation of drawings]

FIG. 1 is a plan view of the electric I4i board of the present invention, and FIGS. 2 and 3 are respectively shown in 1-1 of FIG. llll-l11 sectional view, Figure 4 t shows the inside of the manifold part (111 structure), and is a partial cross-sectional view (left figure) and a partial plan view (right figure). 1... Electrode part , 2... Manifold part, 3... Reaction gas supply passage, 4...
Separator, 5... Reaction gas flow path, 30...
...Flexible graphite sheet. 40...Fluororesin layer. Agent 1F Buri July 1 Yoshio Kuchi Figure 4 Procedural Amendment October 1985/l Day 2 Title of Invention Fuel cell electrode substrate with manifold and its manufacturing method 3 Relationship with the case of the person making the amendment Patent applicant name (110) Kureha Chemical Industry Co., Ltd. 4, Agent 5 Yamada Building, 1-1-14 Shinjuku, Shinjuku-ku, Tokyo, Date of amendment order Proprietor 8, Contents of amendment (1) Box in the specification r 50Kof/c on page 23, line 4
Correct iJ to [20 gr/crti]. (2) In the second line of page 24, [50Kof/CiJ is corrected to [20 gr/mJ].

Claims (15)

[Claims] (1) A fuel in which a porous carbonaceous electrode section equipped with a reaction gas flow path is joined to both sides of a separator via a flexible graphite sheet, and the separator extends outward from the electrode section. A battery electrode substrate with a manifold, characterized in that a manifold part made of a gas-impermeable dense carbon plate having a passage for supplying a reaction gas in an extended part of the separator is joined via a fluororesin layer. Electrode substrate for fuel cells. (2) The electrode substrate for a fuel cell with a manifold according to claim 1, wherein the fluororesin has a melting point of 200° C. or higher. (3) When the porous carbonaceous electrode part is fired at 1,000°C or higher, the bulk density is 0.3 to 0.9 g/cc, 2
The electrode for a fuel cell with a manifold according to claim 1 or 2, which has a gas permeability of 00ml/cm^2.hr.mmAq or more and an electrical resistance of 200mΩ.cm or less. substrate. (4) Separator has a bulk density of 1.4 g/cc or more, 1
Gas permeability of 0^-^6ml/cm^2・hr・mmAq or less, electrical resistance of 10mΩ・cm or less, and 2mm
The electrode substrate for a fuel cell with a manifold according to any one of claims 1 to 3, characterized in that it has the following thickness: (5) Claims 1 to 1, characterized in that the manifold portion has a bulk density of 1.4 g/cc or more and a gas permeability of 10^-^4ml/cm^2.hr.mmAq or less. The electrode substrate for a fuel cell with a manifold according to any one of Item 4. (6) A flexible graphite sheet is interposed between the porous carbonaceous electrode member provided with a reaction gas flow path and a larger separator material so that the separator material extends outward from the electrode member. with adhesive, and further approximately 1
After producing a fuel cell electrode substrate part in which a porous carbonaceous electrode member is bonded to both sides of a separator material via a flexible graphite sheet by firing at . A manifold member made of a gas-impermeable dense carbon plate is bonded to the separator material using a fluororesin sheet or dispersion, and holes are formed in the manifold member at an arbitrary stage to serve as reaction gas supply passages. A method for manufacturing a fuel cell electrode substrate with a manifold according to claim 1, which comprises opening the electrode substrate for a fuel cell with a manifold. (7) The method according to claim 6, wherein the fluororesin has a melting point of 200°C or higher. (8) The electrode member may be [1] a molded member formed by integrally heating and press-molding a mixture of short carbon fibers, a binder, and an organic particulate material, [2] a fired member obtained by firing the molded member of [1] above, [ 3] A solution of phenolic resin is added to the mixed paper obtained by mixing carbon fiber and at least one organic fiber selected from pulp, regenerated cellulose fiber, and polyacrylonitrile fiber together with a papermaking binder (polyvinyl alcohol fiber, etc.). A patent characterized in that a molded member is selected from a molded member in which the impregnated papermaking is used as a gas diffusion portion and a rib portion is formed from the mixture of the above [1], and [4] a fired member in which the molded member of the above [3] is fired. A method according to claim 6 or 7. (9) Any one of claims 6 to 8, wherein the separator material is a dense carbon plate with a firing shrinkage rate of 0.2% or less when fired at 2,000°C. The method described in. (10) Any one of claims 6 to 9, characterized in that the manifold member is a dense carbon material with a firing shrinkage rate of 0.2% or less when fired at 2,000°C. Method described. (11) Claim 6, characterized in that the flexible graphite sheet is produced by compressing expanded graphite particles.
The method according to any one of Items 1 to 10. (12) The flexible graphite sheet is manufactured by compressing expanded graphite particles obtained by acid-treating graphite particles with a particle size of 5 mm or less and further heating, and has a thickness of 1 mm or less and a bulk density of is 1.0-1.5g/cc, compression strain rate is 0.35×10
^-^2cm^2/Kgf or less, and the radius of curvature is 20
12. The method according to claim 11, characterized in that the method has such flexibility that it does not break even when bent up to mm. (13) Any one of claims 6 to 12, wherein the adhesive for the flexible graphite sheet is a thermosetting resin selected from phenol resin, epoxy resin, and furan resin. Method described in Crab. (14) The bonding conditions for the electrode member and separator material are:
Temperature 100-180℃, press pressure 1.5-50Kgf
14. The method according to any one of claims 6 to 13, characterized in that the press time is in the range of 1 to 120 minutes. (15) The joining condition of the manifold member is a pressure of 2K.
gf/cm^2 or more, the melting point of the fluororesin is -50℃
) or above, the method according to any one of claims 6 to 14.