JP2006196280A - Composite sheet body and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite sheet body in which falling-off of particulates accompanied with pulverization of a hydrogen storage alloy, and which is easily deformable, and provide a manufacturing method in which the composite sheet body can be manufactured by a simple process. <P>SOLUTION: Fiber materials such as pulp that become raw materials of paper are dispersed into a solution together with hydrogen storage alloy particulates 3, and by a similar technique as that of tamezuki (accumulated papermaking), this is poured into a wire cloth (papermaking net) to form this into a sheet-form. When the formed sheet body is dried, a fiber structure 2 in which the fiber materials have been entangled mutually and bonded to each other is formed, and the hydrogen storage alloy particulates 3 are dispersed and retained in the inside. Numerous gaps are formed among the fiber materials in the fiber structure 2 that has excellent gas permeability. Furthermore, the hydrogen storage alloy particulates are easily deformable similar to the paper, and they are locked to the gaps among the fiber materials so that their falling-off is prevented. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a composite sheet carrying a hydrogen storage alloy fine powder and a method for producing the same.

  In recent years, hydrogen storage alloys have attracted attention as materials used for secondary batteries and fuel cells. Hydrogen storage alloys have the property of absorbing hydrogen by lowering the ambient temperature or increasing the surrounding hydrogen pressure and releasing hydrogen by raising the ambient temperature or lowering the surrounding hydrogen pressure. Taking advantage of these characteristics, they are used for hydrogen storage bodies such as fuel cells and hydrogen separation membranes, electrode materials for secondary batteries, hydrogen permeable membranes and hydrogen permeable electrodes for fuel cells, and the like.

  It is known that a hydrogen storage alloy is pulverized by repeatedly absorbing and releasing hydrogen, causing distortion in the crystal lattice and generating many cracks in the alloy. Although the contact area with hydrogen increases by pulverization, the absorption and release of hydrogen is enhanced, but the problem is that it drops off from the support and scatters around, or the conductivity deteriorates when used as an electrode. Has also been pointed out.

  Various methods for forming into a sheet shape in consideration of the characteristics of such a hydrogen storage alloy have been proposed. For example, in Patent Document 1, a granular material obtained by pulverizing a hydrogen storage alloy is kneaded with a PVA solution to produce a paste-like material, and a nickel fiber nonwoven fabric is immersed into the ultrasonic bath while stirring the paste-like material. The point that the electrode of the secondary battery is manufactured by drying and pressing after the paste-like material sufficiently enters the nonwoven fabric is described. In Patent Document 2, a pulverized product of a hydrogen storage alloy and nickel fibers are mixed, a PTFE solution is added to a kneaded paste to form a sheet, and then fired to obtain a porous sheet. The point that the electrode was manufactured by adding nickel by electrolytic plating is described. In Patent Document 3, between a pair of rolls, a hydrogen mixture alloy powder mixed with a carbon powder, a fluororesin powder and a binder, and a metal non-porous or perforated plate-like substrate. It is described that the negative electrode sheet in which the powder mixture is fixed to both surfaces of the substrate by supplying and powder rolling is manufactured.

In addition, the point which added the carbon fiber and the carbon powder to the Japanese paper raw material and uniformly dispersed by ultrasonic oscillation is described in Patent Document 4, and the point that the conductive fiber was mixed with the Japanese paper raw material to produce the static eliminating paper. It is described in Patent Document 5.
JP-A-9-92272 JP-A-5-3029 Japanese Patent Application Laid-Open No. 2000-1113880 JP 2001-98493 A Registered Utility Model No. 3000969

  In Patent Document 1, the hydrogen storage alloy granular material is made into a paste and allowed to enter the nickel fiber nonwoven fabric. In Patent Document 2, the hydrogen storage alloy pulverized material is made into a paste and then molded and fired. Therefore, it requires a complicated processing step and a forming step for forming a sheet. Further, in Patent Document 3, the hydrogen storage alloy powder is fixed by a powder rolling method, but an additive such as a binder is required, and a porous material for ensuring the ventilation of hydrogen into the hydrogen storage alloy powder. It is difficult to adjust the rolling to form the properties.

  Then, this invention aims at providing the manufacturing method which can manufacture the composite sheet | seat body which can suppress the drop | offset | aggregation accompanying pulverization of hydrogen storage alloy, and can deform | transform easily, and it with a simple process. It is.

  The composite sheet according to the present invention includes a sheet-like fiber structure in which fiber materials are entangled and bonded to each other by papermaking, and a hydrogen storage alloy fine powder dispersed and held inside the fiber structure. Features.

  Another composite sheet according to the present invention includes a sheet-like fiber structure in which fiber materials are entangled and bonded together by papermaking, and a hydrogen storage alloy fine powder layer dispersed and held in layers inside the fiber structure. It is characterized by having.

  In the above composite sheet, the fiber material is mainly composed of cellulose fibers. Furthermore, the fiber material includes an inorganic fiber or an organic synthetic fiber. Furthermore, it has a porous metal plating layer formed so that the said sheet-like fiber structure and the said hydrogen storage alloy fine powder whole may be coat | covered. Furthermore, the porous metal plating layer is a metal plating layer containing fine particles other than metal.

  A method for producing a composite sheet according to the present invention is characterized in that an aqueous solution in which a fiber material and a hydrogen storage alloy fine powder are mixed and dispersed is made into a sheet, and the formed sheet is dried. To do.

  Another method for producing a composite sheet according to the present invention is to form a sheet by forming an aqueous solution in which a fiber material and a hydrogen storage alloy fine powder are mixed and dispersed, and then drying the formed sheet. The sheet body is subjected to electroless plating in a solution in which a metal compound is dissolved, thereby forming a metal plating layer so as to cover the sheet body and the entire hydrogen storage alloy fine powder, and the metal plating layer Is made porous.

  Still another method for producing a composite sheet according to the present invention is to form a sheet by forming an aqueous solution in which a fiber material and a hydrogen storage alloy fine powder are mixed and dispersed, and then drying the formed sheet. Metal is applied so as to cover the entire sheet body and the hydrogen storage alloy fine powder by performing electroless plating in a solution in which the metal compound is dissolved in the dried sheet body and fine particles other than metal are dispersed. A metal plating layer containing fine particles other than the above is formed.

  In the above method for producing a composite sheet, the aqueous solution is a paper material liquid in which hydrogen storage alloy fine powder is dispersed.

  Still another method for producing a composite sheet according to the present invention is to form a sheet by making an aqueous solution in which a paper fiber material is dispersed, stacking a hydrogen storage alloy fine powder on the surface of the formed sheet, Paper is made by laminating an aqueous solution in which a fiber material is dispersed so as to cover the laminated hydrogen storage alloy fine powder layer, and the laminated sheet is dried.

  Still another method for producing a composite sheet according to the present invention is to form an aqueous solution in which a fiber material is dispersed into a sheet, laminate a hydrogen storage alloy fine powder on the surface of the formed sheet, A solution in which an aqueous solution in which a fiber material is dispersed so as to cover the fine hydrogen storage alloy powder layer is made by paper and laminated, the laminated sheet is dried, and the metal compound is dissolved in the dried sheet A metal plating layer is formed so as to cover the sheet body and the entire hydrogen storage alloy fine powder by performing electroless plating therein, and the metal plating layer is made porous.

  Still another method for producing a composite sheet according to the present invention is to form an aqueous solution in which a fiber material is dispersed into a sheet, laminate a hydrogen storage alloy fine powder on the surface of the formed sheet, Paper is made by laminating an aqueous solution in which fiber materials are dispersed so as to cover the fine hydrogen storage alloy powder layer, the laminated sheet is dried, and the metal compound is dissolved in the dried sheet. By performing electroless plating in a solution in which fine particles other than metal are dispersed, a metal plating layer containing fine particles other than metal is formed so as to cover the sheet body and the entire hydrogen storage alloy fine powder. And

  In the above method for producing a composite sheet, the aqueous solution is a paper solution. Furthermore, a thickener is added to the aqueous solution.

  In the composite sheet according to the present invention, since the hydrogen storage alloy fine powder is dispersed and held inside the sheet-like fiber structure in which the fiber materials are entangled and bonded by papermaking, even if the hydrogen storage alloy is pulverized, the sheet Can be prevented from falling off from the fibrous structure, and since a large number of gaps are formed between the fiber materials, sufficient hydrogen permeability to the hydrogen storage alloy can be secured. That is, according to the method for producing a composite sheet according to the present invention, a paper solution is formed by mixing and dispersing the fiber material and the hydrogen storage alloy fine powder, the sheet is formed, and the formed sheet is dried. Therefore, the hydrogen storage alloy fine powder is dispersed inside the sheet body during paper making, and the hydrogen storage alloy fine powder is reliably held inside the sheet body. Also, by making paper, the fiber material comes to be arranged along the sheet surface, so that a highly flexible structure can be formed, and further, a narrow and narrow gap is formed between the fiber materials. Sufficient breathability is ensured with the reliable holding of the fine powder. Further, it can be manufactured by a process of making paper, forming it into a sheet and drying it, and the manufacturing process becomes extremely simple.

  Further, another composite sheet according to the present invention includes a sheet-like fiber structure in which fiber materials are intertwined with each other by papermaking, and a hydrogen storage alloy fine powder layer dispersed and held in layers inside the fiber structure. Therefore, the hydrogen storage alloy fine powder is held inside the sheet-like fiber structure, and the hydrogen storage alloy fine powder is not held near the surface of the sheet-like fiber structure. Deterrence can be further improved. That is, according to the method for producing a composite sheet according to the present invention, an aqueous solution in which a paper fiber material is dispersed is made into a sheet, and a hydrogen storage alloy fine powder is laminated on the surface of the formed sheet. Paper is made by laminating an aqueous solution in which the fiber material is dispersed so as to cover the laminated hydrogen storage alloy fine powder layer, and the laminated sheet body is dried, so that the hydrogen storage alloy fine powder is surely placed inside the sheet body. It is possible to prevent the hydrogen storage alloy fine powder from being dispersed and held near the surface of the sheet body. And by making paper, the fiber material comes to be arranged along the sheet surface, it can be a highly flexible structure, and furthermore, a narrow and narrow gap is formed between the fiber materials, Sufficient breathability is ensured with the reliable holding of the fine powder. Further, it can be manufactured by a process of making paper, forming it into a sheet and drying it, and the manufacturing process becomes extremely simple.

  And by using a paper stock solution as an aqueous solution in the method for producing a composite sheet, it can be produced using the conventional paper making process as it is, and the production cost can be reduced. In addition, by using cellulose fiber as the fiber material of the composite sheet body, a sheet-like fiber structure with sufficient strength is formed by entanglement between fibers and hydrogen bonding, so there is no need to add additional additives. In addition, a large number of gaps for ventilation are sufficiently secured. Moreover, the composite sheet can be provided with various functions by using, as the fiber material, a material conventionally used for nonwoven fabrics such as inorganic fibers or organic synthetic fibers.

  Then, the composite sheet body has a porous metal plating layer formed so as to cover the entire sheet-like fiber structure and the hydrogen storage alloy fine powder, thereby providing conductivity to the entire composite sheet body. It becomes possible to give the function as. Because it is a porous metal plating layer, the hydrogen absorption and release action of the hydrogen storage alloy can be performed quickly, and the hydrogen storage alloy fine powder is prevented from falling off and the electrode has high flexibility. The composite sheet can be variously deformed and placed inside the battery.

  The porous metal plating layer is formed by subjecting the dried sheet body to electroless plating in a solution that dissolves the metal compound to cover the entire sheet body and the hydrogen storage alloy fine powder, It can be easily formed by making the metal plating layer porous. As another production method, the sheet compound and the entire hydrogen storage alloy fine powder are coated by electroless plating in a solution in which the metal compound is dissolved in the dried sheet and the fine particles other than the metal are dispersed. Thus, a porous metal plating layer can be formed by forming a metal plating layer containing fine particles other than metal. In any of the manufacturing methods, a composite sheet that functions as an electrode having excellent conductivity and air permeability can be manufactured.

  Hereinafter, embodiments according to the present invention will be described in detail. The embodiments described below are preferable specific examples for carrying out the present invention, and thus various technical limitations are made. However, the present invention is particularly limited in the following description. Unless otherwise specified, the present invention is not limited to these forms.

  FIG. 1 is a partially enlarged schematic cross-sectional view of an embodiment of a composite sheet body according to the present invention. The composite sheet 1 is configured such that a hydrogen storage alloy fine powder 3 is dispersed and held inside a sheet-like fiber structure 2 formed by intertwining and bonding a large number of fiber materials. Since the fiber structure 2 is formed by papermaking, the fiber material is arranged substantially along the sheet surface of the composite sheet 1. Accordingly, a large number of elongated gaps are formed between the fiber materials, and the hydrogen storage alloy fine powder 3 is held in the gaps.

  Therefore, the hydrogen storage alloy fine powder 3 is securely held without falling off, and the dropping is suppressed by the intertwined fiber material even if it is further finely powdered by the hydrogen absorption / release action. Become. A large number of gaps between the respective fiber materials are excellent in air permeability and smoothly flow of hydrogen, so that the absorption / release action of the hydrogen storage alloy can be performed quickly. In addition, as described later, when the composite sheet body is immersed in the plating tank when performing electroless plating, the plating solution penetrates to every corner of the composite sheet body, and the entire composite sheet body can be uniformly plated. it can.

  In addition, the fiber structure 2 is formed by arranging a large number of fiber materials along the sheet surface, and thus has excellent flexibility and can be deformed into various shapes. is there. For example, it can be formed into a corrugated plate by a spirally wound shape as shown in FIG. 2 (a) or by bending as shown in FIG. 2 (b). Further, if the folded composite sheet body shown in FIG. 2 (b) is rounded into a cylindrical shape and arranged concentrically as shown in FIG. 2 (c), the composite sheet body can be arranged in a compact manner. And is suitable as a hydrogen storage body such as a fuel cell or a hydrogen separation membrane.

  And the thickness of the fiber structure 2 can be easily adjusted at the time of papermaking, and should just be set suitably according to a use. Even if the thickness of the fiber structure 2 is increased, the air permeability is secured to the inside by the gaps between the respective fiber materials, so that the absorption / release action of the hydrogen storage alloy is not affected.

  The fiber material of the fiber structure 2 is a material conventionally used for paper and non-woven fabric produced by papermaking. For example, as cellulose fiber, fibers generated from plants such as wood, hemp, cotton, and bast are used. Can be mentioned. Examples of inorganic fibers include fibers made of metal, carbon, glass, and ceramic materials, and examples of organic synthetic fibers include polyolefin fibers, polyester fibers, polyimide fibers, and polyamide fibers. Moreover, the fiber length of fiber material should just be a thing which can form paper and a nonwoven fabric. When the fiber length is short, the bonding of the fiber material may be strengthened by using an adhesive, and when the fiber material having thermoplasticity is used, the fiber material should be fused by heating. Also good. Moreover, methods, such as punching used for manufacture of a nonwoven fabric, may be used.

As the hydrogen storage alloy fine powder 3, an ingot is mechanically pulverized and classified so as to have a uniform particle size. A particle diameter of 0.01 μm to 2 mm can be used, and a particle diameter of 0.1 to 10 μm is preferable from the viewpoint of the dispersion state in the solution. The fine powder is degreased by a known method and activated. As a material of the hydrogen storage alloy, known alloys as listed below can be used.
(1) AB ₅ type (rare earth) alloy LaNi ₅ , LaNi ₄ Cu, LaNi ₄ Al, LaNi _2.5 Co _2.5 , La _0.8 Nd _0.2 Ni ₂ Co ₃ , La _0.7 Nd _0.2 Ti _0.1 Ni _2.5 Co _2.4 Al _0.1 , La _0.8 Nd _0.2 Ni _2.5 Co _2.4 Si _0.1 , La _0.9 Zr _0.1 Ni _4.5 Al _0.5 , MmNi ₅ (Mm = Mish metal), MmNi _3.55 Co _0.75 Mn _0.4 Al _0.3 , MmNi _4.2 Mn _0.6 Al _0.2 , MmNi ₃ Co _1.5 Al _0.5 , MmB _x (x = 4.55-4.76, B = Ni, Co, Mn, Al).
(2) AB / A ₂ B type (titanium-based) alloys TiNi, Ti ₂ Ni, TiMn _1.5 , Ti ₂ Ni—TiNi based multi-component alloys (V, Cr, Zr, Mn, Co, Cu, Fe, etc. partial _{replacement); Ti 1-y Zr y} Ni x (x = 0.5~1.45, y = 0~1).
(3) AB ₂ type (Laves phase) alloy _{Ti 2-x Zr x V 4} -y Ni y, Ti 1-x Cr x V 2-y Ni y, ZrV 0.4 Ni 1.6, ZrMn 0.6 Cr 0.2 Ni 1.2, Ti ₁₇ Zr ₁₅ V ₂₂ Ni ₃₉ Cr ₇ , LaNi ₂ , CeNi ₂ .

  The hydrogen storage alloy fine powder may be plated in advance. As the plating treatment in this case, for example, a plating treatment method described in JP-A-9-106817 can be used.

FIG. 3 is an explanatory view showing a process for manufacturing the composite sheet 1 shown in FIG. First, the lump 10 of the fiber material and the hydrogen storage alloy fine powder 11 are put into the water 12 and mixed (FIG. 3A). What is necessary is just to set the input amount of a fiber material according to the magnitude | size and thickness of the composite sheet body 1 to manufacture. What is necessary is just to carry out similarly to the setting at the time of manufacture of normal paper or a nonwoven fabric. Further, the amount of hydrogen storage alloy powder 11 is input according to the performance of the composite sheet. For example, when manufacturing the electrode may be introduced as for example, the thickness of 100μm of the sheet member when the unit area per 0.01g / cm ² ~0.5g / cm ² dispersion retention. A thickener may be added to the water 12 in advance. By adding the thickener, a good dispersion state in the solution of the fiber material and the hydrogen storage alloy fine powder can be maintained. As the thickening agent, neri (made from the roots of troro-aoi or borage) and synthetic glue (PVA or the like) used for Japanese paper are suitable.

  After the charging, the mixed solution is stirred by the stirrer 13 so that the fiber material and the fine alloying alloy fine powder in the solution are almost uniformly dispersed (FIG. 3B). Next, the dispersion solution is poured into a screen net installed on the support frame 14 so as to have a uniform thickness (FIG. 3C). Such a paper-making method is a method generally referred to as “reservoir-making”. FIG. 3C shows a partially enlarged view showing a state where the paper has been rolled. The screen net 15 has a number of fine meshes formed by stretching stainless steel wires vertically and horizontally, and the size of the mesh is set to a size used for normal papermaking. The perforated net 15 is supported at the peripheral edge by the support frame 14, and a sheet body 16 made of paper is formed on the upper surface thereof. When the dispersion solution is poured into the screen 15, fine fiber material and hydrogen storage alloy fine powder fall together with the water through the screen 15, but most of the fiber material remains on the screen 15 in the surface direction. It will be in a state of being arranged almost along. Since the hydrogen storage alloy fine powder is poured together with the fiber material, it is dispersed and held among the remaining fiber material. Fine powder smaller than the mesh of the screen net 15 is also held and held in the gap between the fiber materials. Therefore, it is not necessary to reduce the mesh of the net 15 according to the particle size of the hydrogen storage alloy fine powder. The mesh size of the net 15 is preferably 10 mesh to 500 mesh.

  The sheet body 16 that has been made is placed on the upper surface of the mounting table 17 together with the screen net 15 so that the sheet body 16 faces down, and the screen net 15 is removed (FIG. 3D). If the upper surface of the mounting table 17 is formed in a wavy uneven surface as shown in FIG. 3D ', the shape of the composite sheet can be easily deformed as will be described later.

  The sheet body 16 installed on the mounting table 17 is dried at room temperature (FIG. 3 (e), FIG. 3 (e) ′) so that the fiber materials are coupled in an entangled state and have sufficient strength. (FIG. 3 (f), FIG. 3 (f) ′). In the wet state, the sheet body 16 is soft, so that it easily deforms along the shape of the upper surface of the mounting table 17 by the action of gravity as shown in FIG. Since the sheet body 16 has strength when dried, as shown in FIG. 3 (f) ′, the sheet body 16 retains its shape even when it is removed from the mounting table 17.

  FIG. 4 is a partially enlarged schematic cross-sectional view relating to another embodiment of the composite sheet according to the present invention. In this example, the composite sheet 20 has a fine powder layer 22 in which a hydrogen storage alloy fine powder is held in layers between upper and lower fiber layers 21a and 21b made of the same fiber material as in FIG. Yes. The upper and lower fiber layers 21a and 21b are not separated, and the fiber materials are intertwined and bonded to each other in the same manner as in FIG. 1, but the hydrogen storage alloy fine powder is densely packed in layers between them. Is held. With such a structure, the hydrogen storage alloy fine powder is dispersed and held in the central portion inside the sheet body, and it is possible to further prevent the fine powder from falling off. Further, since the fiber layers 21a and 21b have excellent air permeability characteristics as in the fiber structure of FIG. 1, a sufficient amount of hydrogen flows in the hydrogen storage alloy fine powder held in the central portion. To come.

  FIG. 5 is an explanatory view showing a manufacturing process of the composite sheet body 20. First, the mass 23 of the fiber material is put into the water 24 (FIG. 5 (a)) and sufficiently stirred (FIG. 5 (b)). As described above, a thickener may be added to the water 24 as necessary. The solution in which the fiber material is dispersed by agitation is poured into a stainless steel screen 27 installed on the support frame 26 in the same manner as the pooling described in FIG. 3 to form a sheet-like papermaking layer 28a (FIG. 5 ( c)).

  Next, a fine powder layer 29 is formed by spreading hydrogen storage alloy fine powder in a layered manner on the upper surface of the formed paper making layer 28a (FIG. 5D). Next, a solution in which the fiber material is dispersed is poured onto the fine powder layer 29 formed in the same manner as in the paper making process shown in FIG. 3C to form the paper making layer 28b (FIG. 5E). In this case, by pouring the solution, the fiber material of the paper-making layer 28b is entangled with the fiber material of the lower paper-making layer 28a, and is integrated. Further, although the hydrogen storage alloy fine powder has a small amount of outflow due to the pouring of the solution, most of the fine powder is held by the papermaking layer 28a and is prevented from flowing out.

  The sheet body 30 thus made is placed on the upper surface of the mounting table 31 together with the perforated net 27, the perforated net 27 is removed (FIG. 5 (f)), and dried at room temperature. (FIG. 5 (g)) The strength of the sheet body is generated, and the composite sheet body 20 is finished.

  In the manufacturing process of FIG. 5, it is only necessary to add a process of spraying fine powder to the conventional papermaking process from the dispersion forming process to the papermaking process, and the manufacturing cost can be suppressed.

  In the above example, the method of pooling is used in the paper making process, but paper making can be performed using other methods. For example, “flowing” used in the papermaking process of Japanese paper may be used, and it may be mechanically manufactured using a known papermaking machine.

  When imparting conductivity to the composite sheet as described above, it can be imparted by subjecting the entire composite sheet to metal plating. By using electroless plating for metal plating, it is possible to plate even non-conductive fiber materials, and a metal plating layer is formed to cover the fiber material of the composite sheet and the entire hydrogen storage alloy fine powder. can do.

  As the metal constituting the metal plating layer, Ni, Ni alloy, Cu, Cu alloy, Sn, Cr, Zn, Co, Ti, Al, Au, Ag, Pt, Pt alloy, Pd, Rh, Ru It is selected from metals selected from the group or alloys such as Ni-P, Ni-B, Ni-Cu-P, Ni-Co-P, Ni-Cu-B. By using such a metal, a metal plating layer with little variation in physical properties can be obtained. And since it is a metal plating layer, it is excellent in thermal conductivity, contact resistance is small, and the oxidation of hydrogen storage alloy fine powder is also suppressed. In particular, since Ni has high corrosion resistance and acts as a catalyst for the electrochemical reaction of hydrogen, the Ni-plated composite sheet is suitable for a polymer solid electrolyte fuel cell.

  When such a metal is formed to be porous, it may be formed to be porous after plating. In the case of forming a porous structure, for example, a calcium carbonate powder or an aluminum powder may be included in the plating process, and after forming the plating layer, the powder may be eluted with an acidic solution or an alkaline solution. By forming the porous body in this way, gas permeability can be ensured, and a sufficient amount of hydrogen can be distributed to the hydrogen storage alloy fine powder without impairing the air permeability of the composite sheet body. it can.

  Moreover, a porous metal plating layer can also be comprised by disperse | distributing and containing fine particles other than a metal in the metal mentioned above. As fine particles other than metals, polytetrafluoroethylene (PTFE), polyethylene (PE), polypropylene (PP), ABS resin, polyamide (PA), polysulfone (PSU), AS resin, polystyrene (PS), vinylidene chloride resin (PVDC), vinylidene fluoride resin, PFA resin, polyphenylene ether (PFE), methylpentene resin, methacrylic acid resin, carbon (C), catalyst-supporting fine particles, and thermosetting resin. The particle diameter of the fine particles is preferably 0.01 μm to 500 μm. By using such a compound as fine particles, the metal plating layer is formed to be porous, and excellent gas permeability can be secured, and the characteristics of each compound can be imparted to the metal plating layer.

  When performing electroless plating on the composite sheet body, for example, as shown in FIG. 6, the plating solution is stored in a plating tank 40 and the composite sheet body 1 is immersed. An appropriate amount of calcium carbonate powder or aluminum powder is added to the plating solution, and after plating, these powders are eluted with an acidic solution to make the plating layer porous. Moreover, a porous metal plating layer can be formed by adding an appropriate amount of the above-mentioned fine particles to the plating solution and performing a plating treatment. With this manufacturing method, since the porous metal plating layer can be formed by plating, the manufacturing process can be simplified and the entire metal plating layer can have gas permeability without variation. Moreover, after imparting conductivity by electroless plating, the conductivity may be improved by further electrolytic plating. In FIG. 6, the sheet body is immersed in the plating solution, but the plating process can also be performed by pouring the plating solution into the sheet body or sucking and impregnating the plating solution into the sheet body.

  By covering the composite sheet body with the porous metal plating layer in this way, it has gas permeability and conductivity, and thus is suitable, for example, as a negative electrode material for a nickel metal hydride storage battery.

Prepared as a fiber material using 1.2 kg of Manila hemp and wood pulp (Manila hemp 3 wood 7; manufactured by Fukui Prefecture Washi Kogyo Kyokai), and dispersed so that the fiber content is about 5 g when dried Further, as the hydrogen storage alloy fine powder, 15 g of MmNi _3.55 Co _0.75 Mn _0.4 Al _0.3 was mechanically pulverized and classified to obtain an average particle size of about 30 μm. Then, the fiber material and hydrogen storage alloy fine powder are stirred in water to prepare a paper solution in which the fine powder is dispersed, and the size is 15 cm in length and 10 cm in thickness by the same manufacturing process as FIG. A 1 mm composite sheet was produced. A 50 mesh mesh was used as the net. As shown in FIG. 2 (a), the finished composite sheet can be easily rounded into a spiral shape and can be easily returned to the original plane, and is flexible enough to be deformed into any shape. It was confirmed that In addition, almost no falling off of the hydrogen storage alloy fine powder was observed during the deformation. The content of the hydrogen storage alloy in the finished composite sheet was about 52.3% by weight.

  FIG. 7 is a photograph showing the result of analyzing the cross section of the manufactured composite sheet by SEM. It can be confirmed that the particulate hydrogen storage alloy fine powder is dispersed and held inside the fiber structure in which the string-like fiber materials are joined while being intertwined with each other.

  8 and 9 are graphs showing the results of measuring the hydrogen absorption / release characteristics of the composite sheet. For the measurement, an automatic measuring device (manufactured by Reska) based on JIS H 7201 was used. As samples, (A) a composite sheet body and (B) a fine powder of the same amount as the hydrogen storage alloy fine powder contained in the composite sheet body were prepared. Samples (A) and (B) were each placed in a sample container, and the amount of change in the atomic ratio between hydrogen and the hydrogen storage alloy was calculated by changing the equilibrium pressure of hydrogen in the sample container. FIG. 8 shows a measurement result in a temperature state of 60 ° C., and FIG. 9 shows a measurement result in a temperature state of 20 ° C. In both figures, the vertical axis represents the equilibrium pressure (MPa) of hydrogen, and the horizontal axis represents the value (H / M) obtained by integrating the amount of change in the atomic ratio of the hydrogen storage alloy of hydrogen.

  8 and 9, the composite sheet body (Δ mark) and the hydrogen storage alloy fine powder (◯ mark) are changed in substantially the same manner, and the fiber is related to the absorption / release action of the hydrogen storage alloy in the composite sheet body. It turns out that there is almost no influence by a structure. Therefore, it can be seen that hydrogen is sufficiently circulated to the hydrogen storage alloy dispersed and held inside the sheet body and has excellent gas permeability.

Next, electroless plating was performed on the manufactured composite sheet. The bath composition and conditions of the plating solution are as follows.
<Plating solution>
Nickel sulfate 15 g / liter Sodium hypophosphite 14 g / liter Sodium hydroxide 8 g / liter glycine 20 g / liter PTFE (particle size 0.3 μm) 15 g / liter surfactant 0.5 g / liter <Condition>
pH 9.5
Bath temperature 90 ° C
Stirring time The composite sheet was immersed in a plating tank for 40 minutes and subjected to electroless plating, and then sufficiently washed with water and vacuum-dried for 5 hours. The metal plating layer formed as a result is formed to be porous by containing dispersed fine particles of PTFE. The content of the metal plating layer was about 8% by weight.

  In order to confirm the performance of the plated composite sheet as an electrode, the applicability as a negative electrode of a nickel metal hydride storage battery was examined. As test electrodes, (C) a plated composite sheet body and (D) a conventionally used electrode were prepared. The test electrode (D) is obtained by applying a paste containing a hydrogen storage alloy fine powder to a foamed nickel sheet (0.5 mm thick), rolling and drying, and is conventionally known as a negative electrode material. The weight of the hydrogen storage alloy contained in both test electrodes was 0.168 g (active material 0.087 g).

  As a test apparatus, in addition to the test electrode, a counter electrode made of nickel hydroxide and a separator were arranged in the electrolytic solution in the test cell. Such an arrangement configuration is a general configuration of a nickel metal hydride storage battery. Then, the test electrode and the counter electrode were connected to a DC constant current source for charging / discharging.

The charge / discharge cycle was set as follows.
In electric quantity of charge .... 1 hour per 0.1 C _calc, for 15 hours exemplary charging suspension · 1 hour electricity quantity of discharge ... 1 hour per 0.2 C _calc, 5 hours performed discharge rest .. One hour C _calc is a calculation capacity defined in JIS H7205. Discharging was performed until the potential of the test electrode reached 0.6V. It was calculated discharge capacity C _d defined in JIS H 7205 on the basis of the measurement results for each repeated cycle of charge and discharge. FIG. 10 shows a repeated charge / discharge characteristic diagram based on the discharge capacity. The vertical axis represents the calculated discharge capacity, and the horizontal axis represents the number of cycles.

  Referring to FIG. 10, the test electrode (C) (● mark) and the test electrode (D) (◇ mark) have almost the same charge / discharge characteristics, and are composites coated with a porous metal plating layer. It can be seen that the sheet body has excellent gas permeability and conductivity and has sufficient performance as an electrode.

  The composite sheet according to the present invention can be used for hydrogen storage bodies such as fuel cells, electrode materials for secondary batteries, hydrogen permeable membranes and hydrogen permeable electrodes for fuel cells, and the like. It is also suitable as a material for hydrogen gas sensors and hydrogen compression devices.

It is a partial expanded cross section schematic diagram regarding embodiment which concerns on this invention. It is an external view which shows the shape of a composite sheet body. It is explanatory drawing which shows the manufacturing process of the composite sheet body shown in FIG. It is a partial expanded cross section schematic diagram regarding another embodiment which concerns on this invention. It is explanatory drawing which shows the manufacturing process of the composite sheet body shown in FIG. It is the schematic regarding a plating process. It is a photograph which shows the result of having analyzed the section of the composite sheet object by SEM. It is a graph which shows the measurement result of the absorption and discharge | release characteristic of hydrogen regarding a composite sheet body. It is a graph which shows the measurement result of the absorption and discharge | release characteristic of hydrogen regarding a composite sheet body. It is a repeating charge / discharge characteristic figure based on discharge capacity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Composite sheet body 2 Fiber structure 3 Hydrogen storage alloy fine powder
20 Composite sheet
21 Fiber layer
22 Fine powder layer

Claims (16)

  A composite sheet comprising: a sheet-like fiber structure in which fiber materials are entangled and bonded to each other by papermaking; and hydrogen storage alloy fine powder dispersed and held in the fiber structure.   A composite sheet comprising a sheet-like fiber structure in which fiber materials are intertwined and bonded by papermaking, and a hydrogen storage alloy fine powder layer dispersed and held in layers inside the fiber structure .   The composite sheet body according to claim 1, wherein the fiber material is mainly composed of cellulose fibers.   The composite sheet body according to any one of claims 1 to 3, wherein the fiber material includes inorganic fibers or organic synthetic fibers.   The composite sheet body according to any one of claims 1 to 4, further comprising a porous metal plating layer formed so as to cover the sheet-like fiber structure and the entire hydrogen storage alloy fine powder.   The composite sheet body according to claim 5, wherein the porous metal plating layer is a metal plating layer containing fine particles other than metal.   An electrode comprising the composite sheet according to claim 5.   A method for producing a composite sheet, comprising: making an aqueous solution in which a fiber material and a hydrogen storage alloy fine powder are mixed and dispersed, making a sheet, and drying the formed sheet.   In a solution in which an aqueous solution in which a fiber material and hydrogen storage alloy fine powder are mixed and dispersed is made into a sheet, and the formed sheet is dried, and the metal compound is dissolved in the dried sheet A metal plating layer is formed so as to cover the sheet body and the entire hydrogen storage alloy fine powder by electroless plating, and the metal plating layer is made porous. Production method.   Paper is made from an aqueous solution in which fiber materials and hydrogen storage alloy fine powder are mixed and dispersed, and the sheet is formed into a sheet. The formed sheet is dried, and the metal compound is dissolved in the dried sheet and the metal. Forming a metal plating layer containing fine particles other than metal so as to cover the whole of the sheet body and the hydrogen storage alloy fine powder by performing electroless plating in a solution in which fine particles other than the above are dispersed. A method for manufacturing a composite sheet.   The method for producing a composite sheet according to any one of claims 8 to 10, wherein the aqueous solution is a paper solution in which hydrogen storage alloy fine powder is dispersed.   Paper is made from an aqueous solution in which a paper fiber material is dispersed, formed into a sheet shape, a hydrogen storage alloy fine powder is laminated on the surface of the formed sheet body, and a fiber is formed so as to cover the laminated hydrogen storage alloy fine powder layer A method for producing a composite sheet comprising: making an aqueous solution in which a material is dispersed, making a paper, and laminating; and drying the laminated sheet.   A paper material is formed from an aqueous solution in which the fiber material is dispersed, the sheet is formed into a sheet shape, the hydrogen storage alloy fine powder is laminated on the surface of the formed sheet body, and the fiber material is coated with the laminated hydrogen storage alloy fine powder layer. Paper sheet is laminated by laminating, the laminated sheet body is dried, and the dried sheet body is subjected to electroless plating in a solution that dissolves the metal compound. A method for producing a composite sheet, comprising forming a metal plating layer so as to cover the entire hydrogen-absorbing alloy fine powder, and making the metal plating layer porous.   A paper material is formed from an aqueous solution in which the fiber material is dispersed, the sheet is formed into a sheet shape, the hydrogen storage alloy fine powder is laminated on the surface of the formed sheet body, and the fiber material is coated with the laminated hydrogen storage alloy fine powder layer. Paper is made by laminating and laminating the aqueous solution, and the laminated sheet is dried, and the electroless plating is performed in a solution in which the metal compound is dissolved in the dried sheet and the fine particles other than the metal are dispersed. A method for producing a composite sheet body, comprising: forming a metal plating layer containing fine particles other than metal so as to cover the sheet body and the entire hydrogen storage alloy fine powder.   The method for producing a composite sheet according to any one of claims 12 to 14, wherein the aqueous solution is a stock liquid.   The method for producing a composite sheet according to any one of claims 8 to 15, wherein a thickener is added to the aqueous solution.