Abstract:
A fuel battery in which a gas communication passage, wide in relation to the thickness of the unit cell, is provided and sufficient gas can be supplied to a generating section even if the fuel battery is made thin. A spacer and a separator are stacked. The spacer has a vent step groove where gas passes and a fitting step groove closed by the separator. The step grooves are formed between a square opening disposed in the center and containing a generating section and vent holes constituting manifolds. The separator has a projecting section projecting toward the fitting step groove and disposed between a gas supply section opposed to the generating section and the vent holes constituting the manifolds. The separator further has a communication groove for communicating with the projecting section along the vent holes and the gas supply section. The vent step groove is connected to the communication groove. Therefore, a gas communication passage for communication between the manifolds and the gas supply section is defined.

Description:
CROSS REFERENCE TO PRIOR APPLICATION  
       [0001]     This is a U.S. national phase application under 35 U.S.C. §371 of International Application No. PCT/JP2005/001575 filed Feb. 3, 2005 and claims the benefit of Japanese Application No. 2004-036083, filed Feb. 13, 2004. The International Application was published in Japanese on Aug. 25, 2005 as International Publication No. WO 2005/078837 under PCT Article 21(2).  
       FIELD OF THE INVENTION  
       [0002]     This invention relates to a fuel battery for use as a power source in automobiles and portable terminals.  
       BACKGROUND OF THE INVENTION  
       [0003]     The fuel battery is a device that causes reaction between hydrogen and oxygen in a generating section made up by joining electrodes to both surfaces of an electrolyte layer. It converts chemical energy produced by that reaction into electric energy while producing water. It is drawing attention as a system that is clean and high in electricity generating efficiency. The optimum working temperature of the fuel battery varies with the material of the ion conductor (usually proton conductor) making up the electrolyte layer. Therefore, the fuel battery is classified by the kind of the ion conductor it contains. Of such fuel batteries, one called the proton-exchange membrane fuel battery is expected for its use in automobiles and cell phones because it works at room temperatures and is relatively small in size.  
         [0004]     In the proton-exchange membrane fuel battery, a polymer electrolyte membrane, or the proton conductor, is used as the electrolyte layer. Usually, a pair of electrodes (gas diffusion electrodes), each consisting of an electrolyte layer holding conductive particles carrying catalyst such as platinum and a gas diffusion conductive layer for diffusing supplied gas, are joined by thermo-compression bonding to both surfaces of the polymer electrolyte membrane to form a single body of generating section in which the gas diffusion electrodes and the electrolyte layer are joined together. An example of such fuel batteries are disclosed in Japanese Patent No. JP-A-2002-313358 and JP-A-2003-217339. Then the generating section is interposed between a pair of separators each having gas flow passages formed therein, to form a unit cell. A plural number of the unit cells are placed one over another to form a stack, the main part of the fuel battery.  
         [0005]     Of the polymer electrolyte membrane mentioned above, the one using an ion exchange membrane based on perfluorosulfonic acid, typically Nafion™ is the most advanced in development, closest to the stage of practical use. However, the existing ion exchange membrane based on perfluorosulfonic acid such as Nafion is complicated in manufacturing process, high in cost, posing hindrance to the commercial application of the proton-exchange membrane fuel battery. Further, because its proton conductivity depends greatly on ambient humidity, there is a problem that the fuel battery requires a large-scale humidity control means. Thus, research and development of new proton conductors for replacing such ion exchange membranes have become active.  
         [0006]     To improve practicality of the fuel battery as a power source in fuel battery-powered automobiles and portable terminals, the fuel battery is required of small size and high output. It is desirable to make the unit cell thin and to make the stack high density. However, reducing the unit cell structure in thickness entails a number of drawbacks. One of them is that the thinner the unit cell structure is made, the more it becomes difficult to secure passages for fuel gas and air. To explain more specifically in reference to the unit cell  102  shown in  FIG. 12 , manifolds  106  for flowing fuel gas and air are formed vertically in the perimeter portion of the unit cell  102 , so that fuel gas and air branch from the manifold  106  and are supplied into the gas communication passages  111 , from the gas flow grooves  141  formed along the contact surfaces of the gas diffusion electrode, to the fuel electrode and air electrode. Fuel gas having not reacted yet and water content on the air electrode side are discharged through different gas communication passages to the manifold  106  for discharging gas. Therefore, if the unit cell  102  of the conventional constitution is simply reduced in thickness, gas flow passages such as the gas communication passages  111  are narrowed accordingly, causing a situation in which gas supply amount to the generating section  103  is insufficient.  
         [0007]     This invention is an attempt to solve the above described problems, and therefore, its object is to provide a fuel battery, having gas passages that are wide relative to the thickness of the unit cell, in which sufficient gas is supplied to the generating section even if the cell is reduced in thickness.  
       SUMMARY OF THE INVENTION  
       [0008]     In accordance with one embodiment of the present invention, a proton conducting gel comprises molten glass as a raw material, replacing the conventional polymer electrolyte membrane. The proton conducting gel is a substance, having a dispersion phase made of phosphoric acid chains and a dispersion medium of water, obtained by causing phosphate glass powder obtained by melting method to react with water. While the substance normally has an appropriate degree of viscosity to be easily formed, it can also be solidified by partially crystallizing or by heat treatment and the like so that it loses fluidity. The proton conducting gel exhibits proton conductivity higher than that of the Nafion at ordinary working temperatures (around 80° C.) of the proton-exchange membrane fuel battery. Further, the substance is found to have many other advantages such as stable proton conductivity with respect to ambient humidity and far lower manufacturing cost in comparison with Nafion.  
         [0009]     Embodiments of the present invention pertain to a unit cell structure favorably using the electrolyte layer of the proton conducting gel (patent application 2003-193845). In such a structure, as shown in  FIG. 12 , the proton conducting gel is sandwiched with gas diffusion electrodes  130 ,  130  to form a thin film-shaped electrolyte layer  131 . In this state, the proton conducting gel is solidified, and the electrolyte layer  131  and the gas diffusion electrodes  130 ,  130 , are joined together to make a generating section  103 . Further, the generating section  103  is fit to a spacer  105  by engaging with support projections  151 ,  151  to form a generating structure  110 , in which the generating section  103  and the spacer  105  are united. A unit cell  102  is constituted with the generating structure  110  held between separators  4 ,  4  provided with gas flow grooves  141 . In each unit cell  102  are formed gas communication passages  111  for supplying gas from manifolds  106  to both surfaces of the generating section  103 . Incidentally, while the constitution of the unit cell  102  is developed for fitting the proton conducting gel into the electrolyte layer, it is also proposed to use with the constituting material of the electrolyte layer replaced with other proton conductor.  
         [0010]     This invention relates to a fuel battery made by piling up a plural number of generating structures and separators, with each generating structure comprising a generating section of a thin plate shape made by joining gas diffusion electrodes to both surfaces of an electrolyte layer. The generating structure further comprises an insulating spacer surrounding the parametric edge of the generating section, with each separator formed in its center with a gas supply section having a contact section for contacting the generating section and a gas flow groove to be placed over the generating structure so that the gas supply section faces the generating section. The generating section is of a square shape and the spacer is formed in its center with a square containing opening for containing the generating section in alignment. The upside and underside of the perimeter of the containing opening are each formed with an attachment seat for the separator to attached to. Wide vent openings are formed in four positions opposing respective side edges of the containing opening. The portion between each vent opening and each side edge of the containing opening is formed with vent step grooves for passing gas and fit step grooves to be closed with the separator in pairs on upside and underside and, as for the same surface, placed by turns along the parametric direction of the containing opening. The separator is made of metallic sheet with its central upside and underside formed with square gas supply sections to be attached with its upside and underside parametric edges in contact to the attachment seat. Its parametric section is formed with four wide vent holes respectively conforming to the vent openings of the spacer in the direction of piling up and a raised portion raised on either one side for fitting into the fit step groove is formed between each side edge of the gas supply section and each vent hole. Each raised portion is formed with a communication groove communicating with the vent hole and the gas supply section along planar direction, and joining with the vent step groove of the spacer.  
         [0011]     According to the above constitution, as the separators are attached to both surfaces of the generating structure, the unit cell is formed in which the generating section installed in the center of the generating structure faces the gas supply section provided in the center of the separator. According to one arrangement of the invention, the gas supply sections are provided on both surfaces in the center of the separator, so that a stack consisting of a plural number of piled up unit cells may be formed with the separators and generating structures placed one over another. As they are piled up, the vent openings of the spacers and the vent holes of the separators are aligned in the piling up direction. Manifolds for supplying and discharging fuel gas and air are formed in positions opposing the parametric edges of the square generating section and the gas supply section superposed in piling up direction. Also according to the invention, by attaching the separators to both surfaces of the generating structure, the raised portions of the separator are fit into the fit step grooves. At the same time, by joining the communication grooves in the raised portions to the vent step grooves, gas supply passages are formed to make communication between the manifolds and the gas supply section. In other words, the gas communication passages are formed not only with the grooves formed in the separator, but also by joining together the communication grooves formed in the separator and the vent step grooves of the spacer. Therefore, it is possible to increase the depth of the gas communication passage relative to the unit cell thickness in comparison with the conventional arrangements. Also according to the above constitution, the manifolds are formed in positions facing respective side edges of the gas supply section, while the gas communication passages make mutual communication between the manifolds located on both sides of the gas supply section through the gas supply section located on the same surface side. As a result, fuel, gas and air flowing through the manifolds are supplied from the side edge on one side of the gas supply section and flow out of the side edge on the opposite side. This makes it possible to increase the width of the gas communication passage up to the length of the side edge of the gas supply section. Furthermore, because the constitution according to the invention uses metallic sheet suited for reducing thickness and cost of the separator, it can harmonize not only with the gas flow passage but also with other constitution necessary for reducing thickness.  
         [0012]     Here, it is proposed that the gas supply sections on both surfaces of the separator are each constituted with a plural number of projections projecting on both surface sides and having contact portions near their peaks for contacting the generating section, and with mesh-like gas flow grooves formed among the peaks of the projections. According to such an arrangement, the projections may be easily formed by a simple press process applied to a metallic sheet. It is also possible to form mesh-like gas flow grooves by forming the projections in appropriate positions, such that the gas supply sections may be formed on both surfaces of the separator.  
         [0013]     The gas communication passage may be enlarged not only in the depth direction but also in the width direction. On the other hand, however, if the gas flow passage is widened, depression at the end portion of the generating section is weak in the thickness direction, such that the generating section is likely to deform in the thickness direction. Therefore, it is preferable to provide a support member placed in the width direction inside the mutually joined vent step groove and communication groove to bring the inside end on the vent step groove side into contact with the end portion of the generating section in the thickness direction. This makes it possible to securely hold the generating section so that it does not deform even if the generating section is mechanically pliable, which in turn makes it possible to use a thin generating section in the unit fuel battery while enlarging the gas communication passage in the width direction. Incidentally, the electrolyte layer of this invention may be made not only of the above-described proton conducting gel but also any other materials commercially available. Further, the generating structure is not limited to the one in which the generating section and the spacer are assembled to be a single member but may be one in which they are separable.  
         [0014]     In the fuel battery described above, the gas communication passage for making communication between the manifold and the gas supply section is formed by joining together the vent step groove formed in the spacer and the communication groove formed in the separator. Therefore, it is possible to form the gas communication passage having a smaller thickness relative to the thickness of the unit cell in comparison with conventional arrangements. Therefore, it is possible to make the unit cell thinner, make the stack of a higher density, and realize a fuel battery that is compact and of a high output. Also according to the invention, because the manifolds are formed to face respective side edges of the gas supply section, and the mutually opposing manifolds on both sides of the gas supply section communicate with the gas supply section on the same side, the gas communication passage may be widened up to the same width as the side edge length of the gas supply section. Further, because this arrangement uses a separator made of metallic sheet suited for reducing thickness and cost, it also provides an advantage of favorably harmonizing with other constitution suited for reducing thickness.  
         [0015]     In case the gas supply sections on both surfaces of the separator are constituted with a plural number of projections directed toward one surface side and the other surface side with contact portions for contacting the generating section in the vicinity of their peaks and with mesh-like gas flow grooves formed among the peaks of the projections, it is possible to easily form the gas passages on both surfaces of the metallic sheet at a low cost.  
         [0016]     Further, in case a support member placed in the width direction inside the mutually joined vent step groove and communication groove to bring the inside end on the vent step groove side into contact with the end portion of the generating section in the thickness direction is provided, the end portion of the generating section may be held in a stabilized manner even if the gas communication passage is enlarged in the width direction. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0017]      FIG. 1  is an enlarged side view of a stack  8  made by piling up unit cells  2 .  
         [0018]      FIG. 2  is an exploded perspective view of the stack  8 .  
         [0019]      FIG. 3  shows the section A-A in  FIG. 1 .  
         [0020]      FIG. 4  shows the section B-B in  FIG. 3 .  
         [0021]      FIG. 5  is a plan view of a generating structure  10 .  
         [0022]      FIG. 6  shows the section C-C in  FIG. 5 .  
         [0023]      FIG. 7  is an exploded perspective view of a separator  4  and a support member  9 .  
         [0024]      FIG. 8  is a plan view of the separator  4 .  
         [0025]      FIG. 9  shows the section D-D in  FIG. 8 .  
         [0026]      FIG. 10  is a plan view of the support member  9 .  
         [0027]      FIG. 11  is a view as seen from the lower section in  FIG. 10 .  
         [0028]      FIG. 12  is a side view in vertical section of a conventional unit cell  102 . 
     
    
     DETAILED DESCRIPTION  
       [0029]     For convenience, below is a brief description of several of the reference numerals and symbols mentioned throughout the following detailed description. 
         1 : fuel battery      2 ,  102 : unit cell      3 ,  103 : generating section      4 ,  104 : separator      5 ,  105 : spacer      6   a - 6   d ,  106 : manifold      7 : positioning hole      8 : stack      9 : support member      10 ,  110 : generating structure      11   a - 11   d ,  11 : gas supply passage      30   a ,  30   b ,  130 : gas diffusion electrode      31 ,  131 : electrolyte layer      40 : gas supply section      42 : gas flow groove      42 : round projection      43 : vent hole      44 : raised portion      45 : communication groove      46 : through hole      47 : contact portion      48 : contact seat surface      50 : containing opening      51 ,  151 : support projection      52 : vent opening      53   a : vent step groove      53   b : fit step groove      54 : through hole      55 : attachment seat      90 : support plate      91 : leg        
 
         [0061]     An embodiment of the invention is described with reference to the drawings.  FIGS. 1 and 2  show a stack  8  of a fuel battery  1  in accordance with a first embodiment. The stack  8  is made by piling up a plural number of thin plate-shaped, rectangular unit cells  2 . The stack  8  is provided with four, wide manifolds  6   a - 6   d  running vertically through the parametric portions of the unit cells  2 . The manifolds  6   a - 6   d  of the unit cells  2  are: the manifold  6   a  for supplying fuel gas (hydrogen) to the fuel electrode side, the manifold  6   b  for supplying air (oxygen) to the air electrode side, the manifold  6   c  for discharging fuel gas having not reacted in the unit cells  2  out of the fuel electrode side, and the manifold  6   d  for discharging water content produced by the cell reaction and air after the reaction out of the air electrode side. The stack  8  is formed with positioning holes  7 ,  7  running through its comer portions. The unit cells  2  are stacked in alignment as positioning rods (not shown) are inserted into the positioning holes  7 ,  7 . While gas supply devices for forcing fuel, gas and air into the manifolds  6   a ,  6   c  and current collectors as well as the stack  8  are attached to the fuel battery  1 , these devices may be similar in constitution to those of the known proton-exchange membrane fuel battery, and therefore, their description is omitted.  
         [0062]     As shown in  FIGS. 2 and 3 , the unit cell  2  includes: a thin plate-shaped generating section  3  is surrounded with a flat spacer  5  to form a single body of generating structure  10 , with its both surfaces covered with separators  4 ,  4 , with their centers each formed with a gas supply section  40 . The gas supply sections  40  formed on both upper and lower surfaces of the separator  4 , as the upper and lower gas supply sections  40  come into contact with the generating sections  3 , are commonly used with the neighboring unit cells  2 . In other words, the stack  8  is formed by alternately piling up the generating structures  10  and the separators  4 . Further, according to this embodiment as will be described later, a support member  9  for supporting the parametric portion of the generating section  3  in the thickness direction is provided between the generating structure  10  and the separator  4 .  
         [0063]     The generating section  3  is made by joining gas diffusion electrodes  30   a  and  30   b  to both surfaces of the electrolyte layer  31 . The gas supply section  40  faces and contacts the gas diffusion electrodes  30   a  and  30   b  of the generating section  3 , so that, through the contact portion  47 , the gas diffusion electrodes  30   a  and  30   b  come into electrical contact with the separator  4 . The gas supply section  40 , excluding the contact portion  47 , is made a gas flow groove  41  for gas to flow along the gas diffusion electrodes  30   a  and  30   b  . Through the gas flow groove  41 , fuel and gas are supplied to the gas diffusion electrodes  30   a  and  30   b , and water content produced in the generating section  3  flows toward the gas flow groove  41 .  
         [0064]     As for the unit cells  2  in  FIG. 3 , its upper side is assumed to be the fuel electrode while lower side the air electrode. As seen in  FIGS. 3 and 4 , gas communication passages  11   a  and  11   c  for circulating fuel gas to the gas supply section  40  are formed between the gas supply section  40  in contact with the upper surface of the generating section  3  and the manifolds  6   a ,  6   c  for letting fuel gas flow. In other words, as for the unit cell  2  of this embodiment, the fuel gas flowing through the manifold  6   a  on the left side in  FIG. 3  flows through the gas communication passage  11   a , and is supplied from the gas flow groove  41  on the upper side (fuel electrode side) of the generating section  3  to the gas diffusion electrode  30   a  on the fuel electrode side. Fuel gas having not reacted flows through the gas communication passage  11   c  to the manifold  6   c  on the right side in  FIG. 3 .  
         [0065]     Referring to  FIG. 4 , gas communication passages  11   b  and  11   d  for circulating air to the gas supply section  40  are formed between the gas supply section  40  contacting the air electrode side of the generating section  3  and the manifolds  6   b ,  6   d  through which air flows. Similar to the fuel electrode side, the oxygen flowing through the manifold  6   b  on one side flows through the gas communication passage  11   b  to the gas flow groove  41  on the air electrode side, and is supplied to the gas diffusion electrode  30   b  on the air electrode side. Water content produced in the gas diffusion electrode  30   b  by cell reaction and air having not reacted pass through the gas communication passage  11   d  and flow out to the manifold  6   d  on the other side.  
         [0066]     As shown in  FIG. 2 , in the unit cell  2 , the manifolds  6   a ,  6   c  for flowing fuel gas are formed on both sides of the gas supply section  40 , and the manifolds  6   b ,  6   d  for flowing air are formed on both sides of the gas supply section  40 , so that fuel gas and air flow crisscross each other in the gas supply sections  40 ,  40  contacting the fuel electrode side and the air electrode side of the generating section  3 . Incidentally, the fuel electrode side and the air electrode side of the unit cell  2  of this embodiment are symmetric on both sides. Because their difference is on the operational matter such as difference in the gas supplied to the gas supply section  40 , their constitution is explained without discrimination between both the electrodes. As a matter of course, because this is an embodiment, the present invention need not be embodied with identical constitution on both the fuel electrode side and the air electrode side. Therefore, there is no problem in making both the electrodes asymmetric in constitution.  
         [0067]     The constitution of the generating structure  10  and the separator  4  making up the unit cell  2  is described below. The generating structure  10  is of a square shape made by surrounding the thin plate-shaped generating section  3  with the flat-shaped insulating spacer  5 . The generating section  3  and the spacer  5  are inseparably assembled by causing the entire perimeter of the generating section  3  to engage with the support projection  51  formed on the inside parametric portion of the containing opening  50  formed in the center of the spacer  5 .  
         [0068]     As shown in  FIGS. 5 and 6 , the generating section  3  is made by joining a pair of gas diffusion electrodes  30   a  and  30   b  to both opposite surfaces of the evenly thick, film-shaped electrolyte layer  31 .  
         [0069]     The gas diffusion electrodes  30   a  and  30   b  are each made of a porous carbon paper, of a thickness of 1 mm or less, cut to a square shape. One entire surface of the carbon paper is applied with carbon particles carrying platinum to form a catalyst layer. The gas diffusion electrodes  30   a  and  30   b  may favorably use gas diffusion electrodes made up of a catalyst layer and a gas diffusion conductive layer that are used in existing proton-exchange membrane fuel battery. Therefore, details on their constitution and manufacturing process are omitted here. Further, while the gas diffusion electrodes  30   a  and  30   b  used are preferably about the same in shape, they may be different in materials and catalyst conforming to the cell reaction of both the electrodes.  
         [0070]     The constituent material used in the electrolyte layer  31  is proton conducting gel obtained from calcium phosphate glass. The proton conducting gel of this embodiment was made in the following process. First, dry mixed powder of calcium carbonate and phosphoric acid was prepared to be a composition of 50 mol percent with phosphoric acid converted to P 2 O 5 . Then, the dry mixed powder is melted in an electric furnace through heat treatment at 1300 degrees C. for 0.5 hours. After that, the molten matter is let to flow onto a carbon plate and rapidly cooled down to room temperatures to obtain calcium phosphate glass. The calcium phosphate glass obtained is pulverized in a mortar until the particle diameter is 10 micrometers or less. The obtained powder is then put into a plastic Petri dish, stirred while adding the same weight of distilled water, covered with a  11   d  to prevent drying, and let it stand in that state for three days at room temperatures. This causes phosphate glass powder to react with water, so that pliable proton conducting gel is obtained in which calcium phosphate molecule chains are dispersed in water. The proton conducting gel is put between a pair of gas diffusion electrodes  30   a  and  30   b  with their catalyst layers facing inward, heat-treated (for example at a temperature of 90 degrees C., a humidity of 90 percent, for six hours) with the proton conducting gel in the state of being formed and held in a thin film shape. The proton conducting gel is solidified to make it an electrolyte layer  31  that is unlikely to deform. At the same time, the electrolyte layer  31   a  and the gas diffusion electrodes  30   a  and  30   b  are inseparably joined together into a single generating section  3 .  
         [0071]     The spacer  5  is made by cutting out a rectangular Teflon sheet with its center formed as shown in  FIG. 5  with a square containing opening  50  for containing the generating section  3 . The containing opening  50  is formed in a square shape to conform to the gas diffusion electrodes  30   a  and  30   b  and to be able to contain the generating section  3  in alignment. As shown in  FIGS. 5 and 6 , support projections  51  projecting inward for contacting the perimeter edges of the gas diffusion electrodes  30   a  and  30   b  are provided on the perimeter edges of the containing opening  50 . The projection  51  is provided as shown in  FIG. 6  in the center of thickness of the containing opening  50 . The inside perimeter of the spacer  5  is formed with an inward directed rectangular projection in vertical section.  
         [0072]     Upper and lower sides of the perimeter of the spacer  5  are formed with attachment seats  55  for the separator  4  to be attached to. The attachment seat  55  defines the thickness of the generating section  3  so that the gas supply section  40  comes into contact with the gas diffusion electrodes  30   a  and  30   b  under an appropriate force and that no excessive force is applied to the generating section  3  in the state of the separator  4  attached to the generating structure  10 . Four positions opposite the perimeter edges of the containing opening  50  are each formed with a vent opening  52 . The vent opening  52  is approximately the same in length as the perimeter edge of the containing opening  50  to make up the manifolds  6   a - 6   d  when piled up. Two through holes  54 ,  54  for making up the positioning holes  7  are bored in two parametric comers.  
         [0073]     A vent step groove  53   a  and a fit step groove  53   b  are formed on upper and lower sides of the portion between each vent opening  52  and each side edge of the containing opening  50 . The vent step groove  53   a  and the fit step groove  53   b  are formed as shown in  FIGS. 5 and 6  to form a pair on upper and lower sides and, as for the same side, placed alternately along the parametric direction of the containing opening  50 . In other words, on the same surface of the spacer  5 , the vent step grooves  53   a ,  53   a  oppose each other, and the fit step grooves  53   b ,  53   b  oppose each other across the containing opening  50 . Incidentally in this embodiment, the vent step groove  53   a  and the fit step groove  53   b  are not made different in shape, so that they are used in common.  
         [0074]     The generating section  3  and the separator  4  are put together simultaneously with making the generating section  3 . In other words, in the manufacturing process of the generating section  3  described above, the generating section  3  is made by placing the pliable proton conducting gel between a pair of the gas diffusion electrodes  30   a  and  30   b  and then solidifying the proton conducting gel. In this embodiment, however, the support projections  51  for the spacer  5  are interposed between the perimeter edges of the gas diffusion electrodes  30   a  and  30   b  simultaneously with placing the proton conducting gel between the gas diffusion electrodes  30   a  and  30   b  . While holding the above state unchanged with a jig or the like, proton conducting gel is solidified to produce the generating section  3  in which the electrolyte layer  31  is tightly attached to the gas diffusion electrodes  30   a  and  30   b  . At the same time, the generating section  3  may be fit into the containing opening  50  by causing it to engage with the support projection  51  of the spacer  5 .  
         [0075]     The separator  4 , as shown in  FIGS. 7-9 , is made of a square metallic sheet with a square gas supply section  40  formed in its center and with both sides of its perimeter portion made as contact seat surfaces  48  for tightly contacting the attachment seat  55  of the spacer  5 . As the materials for constituting the separator  4  those used for the separator of the proton-exchange membrane fuel battery, such as stainless steel and titanium with excellent corrosion resistance and conductivity may be favorably used.  
         [0076]     The gas supply section  40  is formed with a plural number of round projections  42  formed to project on upper and lower surfaces of the metallic sheet. The round projections  42  are formed by press-forming the metallic sheet with crisscross rows of projections  42  projecting alternately on opposite surfaces. As for the gas supply sections  40  on both upper and lower surfaces, the portion near the peak of each round projection  42  is made a contact portion  47  for contacting the generating section  3 , while the portion excluding the contact portion  47  is made a mesh-like gas flow groove  41 . According to this embodiment as described above, the gas supply section  40  is brought into contact with the generating section  3  through the portions near the peaks of a plural number of the round projections  42 , so that the contact portions  47  are made discontinuous in the planar direction, and that the mesh-like gas flow grooves  41  are formed to meander among the contact portions  47 . As a result, the gas flow grooves  41  of the gas supply section  40  permits gas to flow crisscross along planar direction. Therefore, fuel gas and air may be caused to flow crisscross each other through the gas supply sections  40  on upper and lower surfaces. As described above, because the gas supply section  40  of such a shape may be made by simply press-processing a metallic sheet, it has an advantage of being manufactured easily at a low cost. The gas supply section  40  and the generating section  3  are both of a square shape so that, when piled up in contact with each other, they are almost conforming as seen in piling up direction. However, the gas supply section  40  is made slightly smaller than the surface of the generating section  3  so that the perimeter of the generating section  3 , when piled up, projects slightly beyond the gas supply section  40 .  
         [0077]     Elongated vent holes  43  are formed in positions, on the contact seat surfaces  48  around the gas supply section  40 , opposite the side edges of the gas supply section  40 . The vent hole  43  is approximately the same in length as the opposing side edge of the gas supply section  40 , formed in a position aligned with the vent opening  52  of the spacer  5  in the piling up direction. The vent hole  43  and the vent opening  52  are placed one over another in the piling up direction to make up the manifolds  6   a - 6   d  . Through holes  46 ,  46  for making up the positioning holes  7 ,  7  are also formed in perimeter corners.  
         [0078]     A rectangular, raised portion  44  raised on either one surface side is formed between each vent hole  43  and each side edge of the gas supply section  40 . A communication groove  45  is formed to make communication between the vent hole  43  and the gas supply section  40  along the planar direction in each raised portion  44 . The raised portion  44  is made in a shape that, when piled up, conforms to both the vent step groove  53   a  and the fit step groove  53   b  of the spacer  5  in the piling up direction. The raised portions  44  located opposite each other on both sides of the gas supply section  40  are raised on the same surface side. The raised portions  44  located adjacent to each other around the gas supply section  40  are raised on opposite surface sides. Referring to  FIGS. 3 and 4 , when the separators  4  and the spacers  5  are piled up one over another, the raised portion  44  is fit to the neighboring fit step groove  53   b , and the neighboring communication groove  45  is joined to the vent step groove  53   a , to form each of the communication passages  11   a - 11   d  of the unit cells  2 .  
         [0079]     Also as described above, in the unit cell  2  of this embodiment, the support member  9  for supporting the parametric portion of the generating section  3  in the thickness direction is provided between the generating structure  10  and the separator  4 . The support member  9  is made as shown in  FIGS. 10 and 11  by joining together two pieces of formed stainless steel sheets in the length direction to have a rectangular support plate  90 , and legs  91  provided in the center and at both ends of the rectangular support plate  90 . The support member  9  as shown in  FIG. 7  is approximately the same in size as the communication groove  45 . The support member  9  is fixed in the state of the legs  9  being brought into contact, in advance, with the bottom surface of each communication groove  45  of the separator  4 . The support plate  90  of the support member  9  is attached to the bottom surface of the vent step groove  53   a  as shown in  FIGS. 3 and 4  in the state of the separators  4  and the generating structure  10  being piled up. The inner end (symbol x in  FIG. 3 ) of the support plate  90  supports the end of the generating section  3  in the thickness direction.  
         [0080]     On the basis of the constitution of the separators  4  and the generating structure  10  described above, the constitution of the stack  8  of this embodiment is detailed as below. The stack  8  of the fuel battery  1  of this embodiment is made up by piling up the separators  4  and the generating structures  10  alternately. As shown in  FIGS. 3 and 4 , the gas diffusion electrodes  30   a ,  30   b  on both surfaces of the generating section  3  are brought into contact with the gas supply section  40  of the separator  4  by joining the attachment seat  55  of the spacer  5  to the contact seat surface  48  of the separator  4 . At the same time, the raised portion  44  of the separator  4  fits into the fit step groove  53   b  of the spacer  5  to close it. At the same time, the communication groove  45  within the raised portion  44  joins to the vent step groove  53   a  of the spacer  5  to form the gas communication passages  11   a - 11   d  causing the manifolds  6   a - 6   d  to communicate with the gas supply section  40 . Therefore, the gas communication passage  11  of the unit cell  2  of this embodiment is formed by joining the grooves formed in the separator  4  as well as in the spacer  5 , so that the depth of the gas flow passage relative to the thickness of the unit cell  2  is made deeper than that according to the conventional constitution. This embodiment also makes it possible to increase the width of the gas communication passages  11   a  - 11   d  up to about the same as the length of each side edge of the square-formed gas supply section  40 . Therefore, in the fuel battery  1  according to this embodiment, width of the gas communication passages  11   a - 11   d  relative to the size of the unit cell  2  is made far wider than according to the background art. Therefore, even if the width of the gas communication passage of the unit cell  2  is held unchanged, the unit cell  2  of this embodiment may be made thinner than that of the background art, so that the stack  8  may be made with high density without sacrificing output.  
         [0081]     In the unit cell  2  of this embodiment as described above, because the perimeter portion (portion x in  FIG. 3 ) of the generating section  3  is supported in the thickness direction by means of the support member  9  provided in the width direction within the gas communication passages  11   a - 11   d , it is possible to support the generating section  3  in stabilized manner without sustaining deformation even if the width of the gas communication passages  11   a - 11   d  is made approximately the same as the length of each side edge of the gas supply section  40 . Therefore, the generating section  3  of this embodiment may be used even if its thickness is reduced down to the extent that invites reduction in mechanical strength. Therefore, the unit cell  2  may be made thinner.  
         [0082]     Further, because the separator  4  of this embodiment is made of a single metallic sheet, it is suited for reducing thickness. The raised portion  44  and the gas supply section  40  of the separator  4  may be formed by a pressing process, and therefore they may be made without cut-processing the metallic sheet.  
         [0083]     As described above, the gas communication passages of the fuel battery according to this embodiment may be made large both in thickness and width relative to the constitution of the unit cell. Therefore, even if the thickness of the unit cell  2  is reduced, it is possible to circulate sufficient gas and make the fuel battery stack of a high density without undergoing reduction in output.  
         [0084]     This invention is not limited to the constitutions and methods of the above embodiments but may be appropriately changed within the scope of the invention. For example, the shapes of the communication groove  45  of the separator  4 , the vent step groove  53   a  and the fit step groove  53   b  of the spacer  5  are not limited to those described in the embodiments but may be changed appropriately. For example, in the above embodiment, while the communication groove  45  and the vent step groove  53   a  are made approximately conforming to each other, they need not completely conform as long as gas communication passages having depth may be formed by joining them.  
         [0085]     Further, while the above embodiment uses the proton conducting gel as the constituent material of the electrolyte layer, any other material may be used as the constituent material as long as the same generating structure  10  as in the above embodiment may be formed. In that case, the generating section  3  and the spacer  5  need not be united into an inseparable form.  
         [0086]     Some of the conventional proton-exchange membrane fuel batteries are known to have a constitution in which cooling water is circulated through the stack. As for the fuel battery of this invention too, it is possible to combine appropriately with existing cooling mechanism such as forming manifolds for circulating cooling water through the stack, or interposing a unit cell having a cooling water passage between the unit cells at certain number of unit cell intervals. Although no mention is made in the description of the above embodiment, it is preferable to appropriately fill the gap between the separator and the generating structure of this invention by appropriately using gaskets and grease for preventing gas leakage. Such a gas leak preventing structure may be appropriately added to embodiments of the present invention.