JP2010244983A - Composite sheet for direct methanol fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite sheet for direct methanol fuel cells, which is excellent in methanol diffusivity and which can supply methanol to a large area of an anode by diffusion pass-through effect even if an area of a methanol solution delivery portion of a fuel cartridge is comparatively small. <P>SOLUTION: The composite sheet for direct methanol fuel cells includes a polyphenylene sulfide-based resin layer and a cellulose fiber layer continuously formed on at least one principal surface of the polyphenylene sulfide-based resin layer, wherein the content of the polyphenylene sulfide-based resin is 10 to 45 wt.%, and the total thickness is 0.05 to 0.2 mm. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention is a direct methanol fuel cell that is excellent in methanol diffusibility and can supply methanol to the anode in a large area by the diffusion permeation effect even if the methanol aqueous solution delivery part from the fuel cartridge has a relatively small area It relates to a composite sheet.

Power consumption and continuous use time are increasing as portable small electronic devices such as mobile phones, personal digital assistants (PDAs), notebook PCs, video cameras, etc. have become multifunctional, and they are installed in portable small electronic devices. There is a strong demand for higher energy density of batteries.

Currently, lithium secondary batteries are mainly used as power sources for portable small electronic devices, but lithium secondary batteries are expected to reach a limit at an energy density of about 600 Wh / L. An early practical application of a fuel cell using a solid polymer electrolyte membrane is expected as a power source to replace the secondary battery.

Among fuel cells, the direct methanol fuel cell (DMFC) can generate electricity by supplying methanol as a fuel or methanol aqueous solution directly into the cell without reforming it into hydrogen. Development is underway. In addition, direct methanol fuel cells are attracting more attention from the viewpoints of high theoretical energy density of methanol, simplification of the system, ease of fuel storage, and the like.

In a direct methanol fuel cell, a method of supplying a methanol aqueous solution by using a diffusion auxiliary machine such as a pump or a fan is generally performed.
However, if a diffusion auxiliary machine such as a pump or a fan is used, downsizing of the entire system is hindered. Therefore, there is a demand for a more simplified and downsized fuel supply system without using these.

As such a fuel supply system, a method of supplying a methanol aqueous solution with high efficiency by utilizing natural diffusion such as capillary phenomenon has been studied. For example, Patent Document 1 discloses a fuel permeation made of a porous material. A method of introducing methanol to the anode by utilizing a capillary phenomenon by disposing a plate is disclosed. Patent Document 2 discloses a fuel introduction body made of a foam, a fiber bundle, a non-woven fiber or the like, and a foam such as a polyurethane foam is used.
However, in these methods, since the diffusibility of methanol is insufficient, it is necessary to enlarge the contact surface between the liquid flow path from the fuel cartridge and the permeation plate, and there is a problem that it is difficult to reduce the size. In addition, as in Patent Document 2, when polyurethane is used as the fuel introduction body, there is a problem that the deterioration due to methanol occurs and the diffusion performance is not stable.

JP 2001-93540 A JP 2003-368866 A

In view of the above situation, the present invention is excellent in methanol diffusibility, and even if the methanol aqueous solution delivery part from the fuel cartridge has a relatively small area, methanol can be supplied to the anode in a large area by the diffusion permeation effect. An object is to provide a composite sheet for a direct methanol fuel cell.

The present invention has a polyphenylene sulfide-based resin layer and a cellulose fiber layer continuously formed on at least one main surface of the polyphenylene sulfide-based resin layer, and the content of the polyphenylene sulfide-based resin is 10 to 45. It is a composite sheet for a direct methanol fuel cell having a weight percent and a total thickness of 0.05 to 0.2 mm.
The present invention is described in detail below.

As a result of intensive studies, the present inventors have found that a sheet used for a direct methanol fuel cell is a cellulose fiber layer continuously formed on at least one main surface of a polyphenylene sulfide resin layer and the polyphenylene sulfide resin layer. In addition, by prescribing the content and total thickness of the polyphenylene sulfide resin, it is possible to provide a composite sheet with extremely high methanol diffusibility while preventing elution and deterioration of impurities due to methanol. It has been found that a direct methanol fuel cell capable of realizing power generation characteristics at a higher current density can be obtained, and the present invention has been completed.

The composite sheet for a direct methanol fuel cell of the present invention has a polyphenylene sulfide resin layer and a cellulose fiber layer continuously formed on at least one main surface of the polyphenylene sulfide resin layer.

The polyphenylene sulfide (PPS) -based resin is excellent in heat resistance because the heat distortion temperature is as high as 260 ° C. Moreover, since it is excellent in chemical resistance and has high rigidity, the obtained sheet has high strength and can be suitably used as a composite sheet for a direct methanol fuel cell.

The polyphenylene sulfide resin is generally synthesized by a polycondensation reaction of p-dichlorobenzene and sodium mercaptan or sodium sulfide.
The polyphenylene sulfide-based resin includes a linear type and a crosslinked type. In the present invention, it is preferable to use a linear type.
Since the crosslinked type has a branched structure, it can be spun by the melt spinning method as in the linear type, and the resulting fiber has a high molecular weight, so that it exhibits high rigidity but lacks stretchability. On the other hand, the linear type has moderate flexibility, and in the step of integrally laminating a sheet made of cellulose fiber and a sheet made of polyphenylene sulfide resin, which will be described later, on the surface of the cellulose fiber layer. It can be suitably used in the present invention because it is excellent in fusibility (particularly in the production of nonwoven sheets by the melt blown method) and is easy to heat-bond at a lower temperature.

The polyphenylene sulfide-based resin is usually used as a homopolymer, but a copolymer having a polyphenylene sulfide unit as a main component and a comonomer unit copolymerizable therewith may be used. Further, for example, a mixed resin with polysulfone, polyolefin or the like can be used.

The preferable lower limit of the number average molecular weight of the polyphenylene sulfide resin is 1000, and the preferable upper limit is 30000. By setting the number average molecular weight within the above range, a direct methanol fuel cell composite sheet having excellent methanol diffusion performance can be obtained. In this specification, the number average molecular weight refers to that measured by gel permeation chromatography (GPC).

As the polyphenylene sulfide resin used in the polyphenylene sulfide resin layer, a polyphenylene sulfide resin having the above-described composition may be used alone, or two or more polyphenylene sulfide resins having the above-described composition may be used in combination. Also good. Moreover, when the said polyphenylene sulfide type resin is two or more layers, although the said polyphenylene sulfide type resin is good also as a thing of a different composition, in order to suppress the trouble by a deformation | transformation etc., it is preferable to set it as the same composition.

The lower limit of the content of the polyphenylene sulfide resin in the composite sheet for a direct methanol fuel cell of the present invention is 10% by weight, and the upper limit is 45% by weight. When the content of the polyphenylene sulfide resin is less than 10% by weight, the diffusion performance of methanol decreases, and when it exceeds 45% by weight, the methanol permeability decreases. The minimum with preferable content of the said polyphenylene sulfide type resin is 12 weight%, and a preferable upper limit is 40 weight%. In addition, content of the said polyphenylene sulfide-type resin represents content per unit area.

You may add well-known additives, such as antioxidant and a heat stabilizer, to the said polyphenylene sulfide-type resin layer in the range which does not impair the essence of this invention.

Examples of the cellulose fibers include natural cellulose fibers such as cotton, hemp, wood (hardwood, conifer) pulp, non-wood pulp (bagasse pulp, straw pulp), and regenerated cellulose fibers such as rayon, polynosic, cupra, tencel, and lyocell. Examples include waste paper pulp.

The cellulose fiber includes semi-synthetic cellulose obtained by modifying pure cellulose, such as cellulose acetate. Pure cellulose fibers have high water retention but low strength. Therefore, by controlling the degree of acetylation of the cellulose acetate, the water retention, strength, etc. can be changed to obtain optimum cellulose fibers. Moreover, you may mix and use a pure cellulose fiber and a cellulose acetate fiber suitably.

The form of the cellulose fiber may be a short fiber or a long fiber, but is preferably a long fiber that hardly causes the fibers to fall off in the system. The cross-sectional shape may be circular or irregular, but a flat cross section is preferred.
In general, the fiber diameter is preferably 0.5 to 100 μm, and more preferably 2 to 70 μm.
In addition, the said fiber diameter is taken as the long diameter of a cross section in the case of an irregular cross section.

The lower limit of the total thickness of the composite sheet for a direct methanol fuel cell of the present invention is 0.05 mm, and the upper limit is 0.2 mm. When the total thickness is less than 0.05 mm, unevenness occurs in diffusion, and when it exceeds 0.2 mm, methanol diffusibility is lowered. The minimum with said preferable total thickness is 0.06 mm, and a preferable upper limit is 0.19 mm.

As a specific configuration of the composite sheet for a direct methanol fuel cell according to the present invention, the polyphenylene sulfide resin (A) and the cellulose fiber layer (B) are (A) / (B) or (B) / (A). It may be a two-layer structure laminated as described above, or may be a three-layer structure laminated as (A) / (B) / (A) or (B) / (A) / (B). It may be a four-layer structure of (A) / (B) / (A) / (B). Especially, it is preferable to make the surface by the side of a fuel supply into a cellulose fiber layer (B).

The composite sheet for a direct methanol fuel cell of the present invention is preferably formed by integrally laminating a sheet made of cellulose fibers and a sheet made of a polyphenylene sulfide resin by heat fusion. The direct methanol fuel cell composite sheet obtained by such a method has a structure in which the cellulose fiber layer and the polyphenylene sulfide resin layer are integrated at the joint, and as a result, the methanol diffusion performance is greatly improved. Can do. In particular, the laminated interface is preferably configured such that a porous polyphenylene sulfide resin is impregnated between cellulose fibers.

The basis weight of the cellulose fiber sheet is not particularly limited, but a preferable lower limit is 10 g / m ² and a preferable upper limit is 37 g / m ² . If the basis weight of the cellulose fiber sheet is less than 10 g / m ² , unevenness may occur during methanol supply, and if it exceeds 37 g / m ² , a sufficient methanol diffusion effect may not be obtained.

Although it does not specifically limit as thickness of the sheet | seat which consists of the said cellulose fiber, A preferable minimum is 0.04 mm and a preferable upper limit is 0.14 mm. If the thickness of the cellulose fiber sheet is less than 0.04 mm or exceeds 0.14 mm, a sufficient methanol diffusion effect may not be obtained.

Examples of the form of the sheet made of the cellulose fiber include a wet papermaking sheet, a wet-spun nonwoven fabric sheet, and a spunbond nonwoven fabric sheet.

The basis weight of the sheet made of the polyphenylene sulfide resin is not particularly limited, but a preferable lower limit is 7 g / m ² and a preferable upper limit is 28 g / m ² . If the basis weight of the sheet made of the polyphenylene sulfide resin is less than 7 g / m ^2, it may unevenness when the methanol feed, and when it exceeds 28 g / m ^2, that sufficient methanol diffusion effect can not be obtained is there. A more preferable lower limit of the basis weight of the sheet made of the polyphenylene sulfide resin is 10 g / m ² , and a more preferable upper limit is 25 g / m ² .

Although it does not specifically limit as thickness of the sheet | seat consisting of the said polyphenylene sulfide type-resin, A preferable minimum is 0.1 mm and a preferable upper limit is 0.3 mm. When the thickness of the sheet made of the polyphenylene sulfide resin is less than 0.1 mm or exceeds 0.3 mm, a sufficient methanol diffusion effect may not be obtained. A more preferable lower limit of the thickness of the sheet made of the polyphenylene sulfide resin is 0.1 mm, and a more preferable upper limit is 0.16 mm.

Examples of the form of the sheet made of the polyphenylene sulfide resin include a spunbond nonwoven fabric sheet, a wet papermaking nonwoven fabric sheet, a wet spinning nonwoven fabric sheet, a nonwoven fabric sheet such as a meltblown nonwoven fabric sheet, a porous sheet by film stretching, and a foamed porous sheet. It is done.

The sheet made of the polyphenylene sulfide resin can be produced by using, for example, a fiber made of a polyphenylene sulfide resin obtained by a melt spinning method or the like.
The fiber form of the fiber made of the polyphenylene sulfide-based resin may be a short fiber or a long fiber, or the cross-sectional shape may be a circle or an irregular cross-section.
Although the fiber diameter of the fiber made of the polyphenylene sulfide resin is different depending on the cellulose fiber to be used, it is generally preferable that the fiber is a finer fiber than the cellulose fiber.
The fiber diameter is preferably 1 to 80 μm, and more preferably 5 to 60 μm. As the fiber diameter increases, the humidification rate for the cellulose fibers is hindered, and the thickness of the resulting direct methanol fuel cell composite sheet itself is also increased, which may be harder than necessary. In addition, the said fiber diameter shall be represented by the average value of a cross-sectional diameter, and shall convert into a circle | round | yen in the case of an irregular cross section.

In addition, by integrally laminating the sheet made of cellulose fiber and the sheet made of polyphenylene sulfide resin by heat fusion, the sheet made of polyphenylene sulfide resin is emptied at the joint portion with the sheet made of cellulose fiber. It can be easily fused and fixed with high adhesion without blocking the hole.
The temperature at the time of heat-sealing is higher than the melting point of the polyphenylene sulfide-based resin, but can be fused at a temperature lower than the melting point of the polyphenylene sulfide-based resin.

The method for producing the direct methanol fuel cell composite sheet of the present invention is not particularly limited. For example, as described above, a sheet made of cellulose fiber and a sheet made of polyphenylene sulfide resin are integrated by heat fusion. The method of laminating is mentioned.
Specifically, for example, a sheet of cellulose fibers and a sheet of polyphenylene sulfide resin are passed through a pair of heated rollers, and the sheet passes at a predetermined speed while applying nipping pressure. And the like.

According to the present invention, a direct methanol type that is excellent in methanol diffusibility and can supply methanol in a large area to the anode by the diffusion permeation effect even if the methanol aqueous solution delivery part from the fuel cartridge has a relatively small area. A composite sheet for a fuel cell can be provided.
In addition to efficient diffusion supply of high-concentration methanol aqueous solution, it can be made thin, and by using natural diffusion using fibers, diffusion auxiliary equipment such as pumps and fans can be used. Therefore, it can be suitably used for a small direct methanol fuel cell.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
Nonwoven sheet made of polyphenylene sulfide on the main surface opposite to the methanol supply surface of a wet papermaking sheet made of cellulose fibers (flat fiber cross-sectional shape, fiber diameter 5 to 55 μm, basis weight 19 g / m ² , thickness 0.11 mm) (Melting point 285 ° C., circular fiber cross-section, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm) and by heating at 135 ° C. for 3 seconds using a hot press machine, Heat-sealing was performed to obtain a composite sheet (two layers) having a total thickness of 0.07 mm and a polyphenylene sulfide content of 35% by weight.
Here, the thickness of each sheet was measured using a digital thickness meter (measurement part φ20 mm) manufactured by Mitutoyo Corporation. As for the fiber diameter, 30 points were marked on the SEM photograph, and the minimum value to the maximum value were recorded. Each sheet basis weight was converted into weighed and the weight per 1 m ² of the test piece of 25 mm × 200 mm.

(Example 2)
Nonwoven sheet made of polyphenylene sulfide (melting point 285 ° C.) with a methanol supply surface of a wet papermaking sheet (flat fiber cross-sectional shape, fiber diameter 5 to 55 μm, basis weight 19 g / m ² , thickness 0.11 mm) made of cellulose fiber , Fiber cross-section circle, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm), and heat-sealed by heating at 135 ° C. for 3 seconds using a hot press machine A composite sheet (two layers) having a total thickness of 0.06 mm and a polyphenylene sulfide content of 35% by weight was obtained.

Example 3
Nonwoven sheet made of polyphenylene sulfide on the main surface opposite to the methanol supply surface of wet papermaking sheet made of cellulose fibers (fiber flat cross section, fiber diameter 5 to 55 μm, basis weight 37 g / m ² , thickness 0.14 mm) (Melting point 285 ° C., circular fiber cross section, fiber diameter 0.8 to 8 μm, basis weight 25 g / m ² , thickness 0.24 mm) and by heating at 135 ° C. for 3 seconds using a hot press machine, Heat-sealing was performed to obtain a composite sheet (two layers) having a total thickness of 0.12 mm and a polyphenylene sulfide content of 40% by weight.

Example 4
Non-woven sheet made of polyphenylene sulfide (melting point 285 ° C.) with a methanol supply surface of a wet papermaking sheet made of cellulose fibers (flat fiber cross-sectional shape, fiber diameter 5 to 55 μm, basis weight 37 g / m ² , thickness 0.14 mm). , fibers circular cross section, the fiber diameter 0.8～8Myuemu, basis weight 25 g / ^{m 2,} placing the thickness 0.24 mm), by heating for 3 seconds at 135 ° C. using a hot press machine, heat sealed A composite sheet (two layers) having a total thickness of 0.12 mm and a polyphenylene sulfide content of 40% by weight was obtained.

(Example 5)
A wet sheet made of two cellulose fibers on both main surfaces of a non-woven sheet made of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 25 g / m ² , thickness 0.24 mm). A paper sheet (flat fiber cross-sectional shape, fiber diameter of 5 to 55 μm, basis weight of 37 g / m ² , thickness of 0.14 mm) is placed and heated at 135 ° C. for 3 seconds using a hot press machine. Thus, a composite sheet (three layers) having a total thickness of 0.19 mm and a polyphenylene sulfide content of 25% by weight was obtained.

(Example 6)
A wet sheet made of two cellulose fibers on both main surfaces of a non-woven sheet made of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm). paper sheet (fiber cross-sectional shape flat, fiber diameter 5～55Myuemu, basis weight 10 g / ^{m 2,} thickness 0.04 mm) was placed on, by heating for 3 seconds at 135 ° C. using a hot press machine, heat-sealing Thus, a composite sheet (three layers) having a total thickness of 0.11 mm and a polyphenylene sulfide content of 33% by weight was obtained.

(Example 7)
A wet sheet made of two cellulose fibers on both main surfaces of a non-woven sheet made of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm). A paper sheet (flat fiber cross-sectional shape, fiber diameter of 5 to 55 μm, basis weight of 37 g / m ² , thickness of 0.14 mm) is placed and heated at 135 ° C. for 3 seconds using a hot press machine. Thus, a composite sheet (three layers) having a total thickness of 0.14 mm and a polyphenylene sulfide content of 12% by weight was obtained.

(Comparative Example 1)
Nonwoven sheet made of polyphenylene sulfide on the main surface opposite to the methanol supply surface of wet papermaking sheet made of cellulose fibers (fiber flat cross section, fiber diameter 5 to 55 μm, basis weight 37 g / m ² , thickness 0.14 mm) (Melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 35 g / m ² , thickness 0.31 mm) and by heating at 135 ° C. for 3 seconds using a hot press machine, Heat-sealing was performed to obtain a composite sheet (two layers) having a total thickness of 0.18 mm and a polyphenylene sulfide content of 49% by weight.

(Comparative Example 2)
A wet sheet made of two cellulose fibers on both main surfaces of a non-woven sheet made of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm). A paper sheet (flat fiber cross-sectional shape, fiber diameter of 5 to 55 μm, basis weight of 40 g / m ² , thickness of 0.18 mm) is placed and heated at 135 ° C. for 3 seconds using a hot press machine. Thus, a composite sheet (three layers) having a total thickness of 0.21 mm and a polyphenylene sulfide content of 11% by weight was obtained.

(Comparative Example 3)
A wet sheet made of two cellulose fibers on both main surfaces of a non-woven sheet made of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 10 g / m ² , thickness 0.11 mm). A paper sheet (flat fiber cross-sectional shape, fiber diameter of 5 to 55 μm, basis weight of 48 g / m ² , thickness of 0.22 mm) is placed and heated at 135 ° C. for 3 seconds using a hot press machine for heat fusion. Thus, a composite sheet (three layers) having a total thickness of 0.23 mm and a polyphenylene sulfide content of 9% by weight was obtained.

(Comparative Example 4)
Nonwoven sheet made of polyphenylene sulfide on the main surface opposite to the methanol supply surface of wet papermaking sheet made of cellulose fibers (fiber flat cross section, fiber diameter 5 to 55 μm, basis weight 9 g / m ² , thickness 0.04 mm) (Melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 5 g / m ² , thickness 0.04 mm) and by heating at 135 ° C. for 3 seconds using a hot press machine, Heat-sealing was performed to obtain a composite sheet (two layers) having a total thickness of 0.04 mm and a polyphenylene sulfide content of 36% by weight.

(Comparative Example 5)
Wet surface composed of two cellulose fibers on both principal surfaces of a nonwoven fabric sheet composed of polyphenylene sulfide (melting point 285 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 35 g / m ² , thickness 0.31 mm) paper sheet (fiber cross-sectional shape flat, fiber diameter 5～55Myuemu, basis weight 37 g / ^{m 2,} thickness 0.14 mm) was placed on, by heating for 3 seconds at 135 ° C. using a hot press machine, heat-sealing Thus, a composite sheet (three layers) having a total thickness of 0.21 mm and a polyphenylene sulfide content of 32% by weight was obtained.

(Comparative Example 6)
Nonwoven sheet made of 6 nylon on the main surface opposite to the methanol supply surface of wet papermaking sheet made of cellulose fibers (fiber flat cross section, fiber diameter 5 to 55 μm, basis weight 20 g / m ² , thickness 0.07 mm) (Melting point: 222 ° C., fiber cross-section circle, fiber diameter: 0.8-8 μm, basis weight: 10 g / m ² , thickness: 0.10 mm) and heating at 210 ° C. for 3 seconds using a hot press machine, Heat-sealing was performed to obtain a composite sheet (two layers) having a total thickness of 0.09 mm and a nylon content of 33% by weight.

(Comparative Example 7)
6 Nylon non-woven fabric sheet (melting point 222 ° C., circular fiber cross section, fiber diameter 0.8-8 μm, basis weight 20 g / m ² , thickness 0.07 mm) A paper sheet (flat fiber cross-sectional shape, fiber diameter of 5 to 55 μm, basis weight of 20 g / m ² , thickness of 0.07 mm) is placed and heated at 210 ° C. for 3 seconds using a hot press machine. Thus, a composite sheet (three layers) having a total thickness of 0.18 mm and a nylon content of 33% by weight was obtained.

(Comparative Example 8)
A wet papermaking sheet made of cellulose fibers (flat fiber cross-sectional shape, fiber diameter 5 to 55 μm, basis weight 20 g / m ² , thickness 0.07 mm, one layer) was used.

(Comparative Example 9)
A non-woven sheet made of polyphenylene sulfide (melting point: 285 ° C., circular fiber cross section, fiber diameter: 0.8 to 8 μm, basis weight: 10 g / m ² , thickness: 0.11 mm, one layer) was used.

(Evaluation)
(Methanol permeation diffusivity test)
About the sheet | seat obtained by the Example and the comparative example, a sheet | seat is mounted in the circular frame shape of inner diameter 76mm, outer diameter 86mm, and height 20mm, and a micropipette is taken from 5 mm above the 1st layer (methanol IN side) surface. 10 μL of a special grade methanol reagent colored with a small amount of blue ink was dropped. After the dropping, the sheet was visually observed, and the blue portion was judged to be due to methanol penetration and evaluated according to the following criteria.

(Methanol permeability)
◯: When the blue part shape of the dripping surface (front) and the opposite surface (back) is oval or circular, and the blue part areas of the front and back are equal
×: When there is no blue part on the back
Unevenness: When the blue part shape on the front and back is mosaic, and the blue part area on the back is small
Regarding Comparative Example 4, it was determined that deformation of the film was observed due to the dropwise addition of methanol, the dimensions were unstable, and the function was not stable.

According to the present invention, a direct methanol type that is excellent in methanol diffusibility and can supply methanol in a large area to the anode by the diffusion permeation effect even if the methanol aqueous solution delivery part from the fuel cartridge has a relatively small area. A composite sheet for a fuel cell can be provided.
In addition to efficient diffusion supply of high-concentration methanol aqueous solution, it can be made thin, and by using natural diffusion using fibers, diffusion auxiliary equipment such as pumps and fans can be used. Therefore, it can be suitably used for a small direct methanol fuel cell.

Claims (5)

Having a polyphenylene sulfide-based resin layer and a cellulose fiber layer continuously formed on at least one main surface of the polyphenylene sulfide-based resin layer;
The content of the polyphenylene sulfide resin is 10 to 45% by weight, and
A composite sheet for a direct methanol fuel cell, having a total thickness of 0.05 to 0.2 mm. 2. The composite sheet for a direct methanol fuel cell according to claim 1, wherein a sheet made of cellulose fiber and a sheet made of a polyphenylene sulfide resin layer are integrally laminated by heat fusion. 3. The direct methanol fuel cell composite sheet according to claim 1, wherein the sheet made of cellulose fibers has a basis weight of 10 to 37 g / m < ² > and a thickness of 0.04 to 0.14 mm. The sheet of polyphenylene sulfide resin has a basis weight of 7 to 28 g / m ² and a thickness of 0.1 to 0.3 mm. Composite sheet. 5. The direct methanol fuel cell composite sheet according to claim 1, wherein the polyphenylene sulfide-based resin is polyphenylene sulfide.