JP2006344434A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell composed of an improved laminated structure of many fuel battery cells, capable of intensively realizing fluid sealing property between superposed separators with high reliability without accompanying assembly of specific components or complication of structure. <P>SOLUTION: Main face sealing rubber layers 38a, 38b are formed respectively on a first separator 20 and a second separator 22 superposed on a film-electrode assembly 18, and linear sealing protrusions 72, of which both faces in width direction is slanted and narrowed toward top end part of the protrusion, are formed on the main face sealing rubber layer 38a, on the other hand, sealing grooves 74 of which both faces in width direction is slanted and widened toward opening side are formed on the main face sealing rubber layer 38b. The sealing protrusions are fitted to the sealing grooves 74 and the faces in width direction of the protrusions and the grooves are pressed to each other, and by the above, the sealing structure is constituted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polymer electrolyte fuel cell, and more particularly to a fuel cell equipped with a novel sealing mechanism capable of obtaining a high and stable sealing property between stacked separators.

  In general, in a polymer electrolyte fuel cell, a membrane / electrode assembly (MEA) in which electrodes are arranged on both sides of a solid polymer electrolyte membrane is overlapped with a pair of separators made of a conductive material on both sides. It is comprised by the fuel cell of a structure. In this fuel cell, a gas flow path is formed between the overlapping surfaces of the MEA and each separator. Through this gas flow path, oxygen (air) as an oxidant is supplied to one surface of the MEA, while hydrogen as a fuel is supplied to the other surface of the MEA. Yes. These oxygen and hydrogen act on both sides of the solid polymer electrolyte membrane, so that an electromotive force is generated by an electrochemical reaction, and power is taken out through a pair of separators.

  Moreover, with such a fuel cell unit, the electromotive force obtained is very small. Therefore, in many cases, a fuel cell that generates a target voltage has a laminated structure in which several tens to several hundreds of fuel cells are stacked in series.

  By the way, in the fuel cell having such a structure, in order to stably obtain a target performance, a high degree of sealing performance with respect to fluid is required between the stacked separators. That is, in each fuel cell unit, a high degree of sealing performance is required in the gas flow path of oxygen or hydrogen supplied to the MEA between the pair of separators stacked with the MEA interposed therebetween. Further, even between the stacked fuel cells, a cooling water channel is formed between the separators stacked on each other. Therefore, a high sealing performance is required in the cooling water channel.

  Thus, for example, a seal structure in which a gasket is sandwiched between separators that are overlapped with each other and sealed in a fluid-tight manner has been proposed. Patent Document 1 (Japanese Patent Application Laid-Open No. 2003-157867) discloses that both sides of the MEA are held by holding a solid polymer electrolyte membrane with a pair of gaskets fixed to both separators that are overlapped with each other. There has also been proposed a sealing structure in which the gas flow paths formed in the above are each fluid-tightly sealed.

  However, further research and experiments by the present inventors have revealed that it is still difficult to obtain sufficient fluid tightness with such a conventional sealing mechanism.

  That is, as described above, the fuel cell is formed with a stacked structure in which a large number of fuel cells are stacked in series. However, in most cases, the tightening force in the stacking direction is generally the both ends in the stacking direction. It can only act in between. As a result, theoretically the same clamping force is applied between the separators stacked between each fuel cell and adjacent fuel cells, but the clamping force is affected by the friction with the clamping member. May vary.

  Further, even if the same tightening force is exerted, dimensional errors and distortions are unavoidable at the time of manufacturing and assembling at each part, member, and part constituting each fuel cell.

  And it became clear that in the fuel cell, the gap between the stacked separators is likely to vary in the fuel cell due to such manufacturing and assembly reasons. Thus, when the gaps between the separators vary, the clamping pressure on the gasket between the separators varies. Therefore, it has been found that it is difficult to stably secure the sealing performance between all the separators with high reliability.

  In order to stably obtain a high level of sealing performance, it is conceivable to increase the tightening force in the stacking direction of the fuel cells, but each member such as the MEA and the separator constituting the fuel cells is very thin. Since the strength is small, there is a risk of damage or the like when the tightening force is increased, which is not realistic. In addition, since the rubber material of the seal ring is required to have durability and sealability against oxygen, hydrogen, water, etc., it is difficult to consider measures by adopting a rubber material having a particularly large elasticity.

JP 2003-157867 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is a fuel cell composed of a stacked structure of a large number of fuel cells, which are superposed on each other. To provide a fuel cell having an improved structure capable of realizing highly reliable fluid tightness between separators without requiring special parts or complicated structures. is there.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  First, according to a first aspect of the present invention, a fuel cell is formed by stacking a separator on both sides of a membrane / electrode assembly in which electrodes are arranged on both sides of a solid polymer electrolyte membrane. In the fuel cell having a laminated structure, the sealing rubber layers are respectively formed on the overlapping surfaces of the separators that are overlapped with each other, and the sealing rubber layer on one of the overlapping surfaces of the separators is on the opening side. A seal groove having a cross-sectional shape that widens toward the top is formed, and a seal protrusion having a cross-sectional shape that narrows toward the front end side is formed on the seal rubber layer on the overlapping surface of the other separator. The seal protrusion is fitted in the seal groove, and the inclined surfaces on both sides in the width direction of the seal protrusion are in relation to the inclined surfaces on both sides in the width direction of the seal groove. That sealing mechanism is configured attached to by induced to elastic deformation, characterized.

  In the fuel cell having such a structure according to this aspect, even if the distance between the opposed surfaces of the pair of separators is different for each fuel cell, the fuel cell can exhibit a stable sealing effect. It is possible to prevent the leakage of gas, oxidant gas, cooling water, etc., and to improve the efficiency of power generation.

  In a fuel cell in which a plurality of separators are stacked and stacked in a stacked state, the distance between the opposing surfaces of adjacent separators may differ depending on the dimensional error of the seal rubber or the difference in elastic force. In a fuel cell, separators that are adjacent in the stacking direction of the separators are formed by forming both side surfaces in the width direction of the seal protrusion and both side surfaces in the width direction of the seal grooves, which are seal surfaces that exhibit a sealing effect by abutment, respectively. Even when the distance between the opposing surfaces changes, the difference in the amount of elastic deformation of the seal protrusion and the seal groove can be kept small. Therefore, in a fuel cell in which a large number of separators are stacked, the desired sealing performance can be stably exhibited between the separators.

  Further, according to a second aspect of the present invention, in the fuel cell according to the first aspect, in the overlapping surface of the separator overlapped with the membrane / electrode assembly interposed therebetween, the periphery of the membrane / electrode assembly The seal mechanism including the seal groove and the seal protrusion is provided so as to surround the seal.

  In the fuel cell having the structure according to this aspect, it is possible to effectively prevent the leakage of the fuel gas and the oxidizing gas, and to stably exhibit the efficient power generation operation.

  Further, according to a third aspect of the present invention, in the fuel cell according to the first or second aspect, a gap exists between the opposing surfaces of the seal rubber layer between the overlapping surfaces of the separators overlapped with each other. And a gap is also present between the bottom surface of the seal groove and the tip surface of the seal protrusion.

  In the fuel cell having the structure according to this embodiment, the inclined surfaces on both sides in the width direction of the seal protrusion are more advantageously pressed against the inclined surfaces on both sides in the width direction of the seal groove. The sealing performance can be effectively demonstrated.

  Further, the seal ridge and the seal groove bulged and deformed by fitting the seal ridge into the seal groove are formed on the gap between the opposed surfaces of the seal rubber layer to be overlapped or on the protruding tip side of the seal ridge. It is possible to deform so as to enter the gap between the bottom surface of the seal groove and the tip surface of the seal protrusion. Therefore, the both side surfaces in the width direction of the seal protrusion and the both side surfaces in the width direction of the seal groove are made uniform, and the sealing effect can be exhibited more effectively.

  According to a fourth aspect of the present invention, in the fuel cell according to any one of the first to third aspects, the seal groove and the seal protrusion are both symmetrical cross-sectional shapes. It is characterized by being.

  In the fuel cell having the structure according to this embodiment, the pressure acting on the inclined surfaces on both sides in the width direction of the seal protrusion and the inclined surfaces on both sides in the width direction of the seal groove is substantially the same. Thus, a substantially equal sealing effect can be obtained and a more stable seal can be realized. In addition, distortion deformation of the seal ridge and seal groove can be avoided, and local stress concentration and variation in seal performance of the seal ridge and seal groove due to such distortion deformation can be effectively prevented. Is possible.

  According to a fifth aspect of the present invention, in the fuel cell according to any one of the first to fourth aspects, an inclination angle of inclined surfaces on both sides in the width direction in a cross section of the seal groove, and the seal protrusion The difference between the inclination angles of the inclined surfaces on both sides in the width direction in the cross section is ± 10 degrees or less.

  In the fuel cell having the structure according to this aspect, by sufficiently reducing the difference in the inclination angle, the pressure contact state between the seal protrusion and the seal groove can be secured on the surface, and the stable sealing performance. Can be achieved.

  According to a sixth aspect of the present invention, in the fuel cell according to any one of the first to fifth aspects, the inclination angle of the inclined surfaces on both sides in the width direction in the cross section of the seal groove, and the seal protrusion The inclination angle of the inclined surfaces on both sides in the width direction in the cross section is 20 degrees or more and 70 degrees or less with respect to the surface of the separator at least in a region where they are pressed against each other.

  In the fuel cell having the structure according to this aspect, since the inclined surfaces on both sides in the width direction of the seal protrusion are pressed against the inclined surfaces on both sides in the width direction of the seal groove, the excellent sealing effect and the adjacent It is possible to achieve avoidance of variation in sealing performance due to variation in the distance between opposing surfaces of matching separators.

  Further, according to a seventh aspect of the present invention, in the fuel cell according to any one of the first to sixth aspects, inclined surfaces on both sides in the width direction in the cross section of the seal protrusion are convex outward. It is characterized by being a curved inclined surface.

  Also in the fuel cell having the structure according to this embodiment, the difference in the sealing effect due to the variation in the distance between the opposing surfaces between the separators can be suppressed, and a stable sealing effect can be obtained.

  In addition, according to an eighth aspect of the present invention, in the fuel cell according to any one of the first to seventh aspects, the width dimension of the opening in the seal groove is the width dimension of the tip in the seal protrusion. And the width of the bottom of the seal groove is smaller than the width of the tip of the seal protrusion.

  In the fuel cell having the structure according to this embodiment, the seal protrusion and the projecting tip can be easily aligned and inserted with respect to the opening of the seal groove, and further pushed, A sealing effect can be stably obtained by press-fitting the seal protrusion into the seal groove.

  According to a ninth aspect of the present invention, in the fuel cell according to any one of the first to eighth aspects, a compression allowance of the seal protrusion is 5 in cross-sectional area between the overlapping surfaces of the separator. It is characterized by being -20%.

  In the fuel cell having the structure according to this embodiment, by setting the compression allowance of the seal protrusion to a predetermined ratio, it is possible to realize a pressing force having an appropriate size capable of obtaining the desired seal performance. In addition, it is possible to achieve both avoidance of variations in sealing performance due to a difference in the distance between the opposing surfaces of the separator. In addition, it is possible to reliably exhibit the desired sealing performance while avoiding problems such as deformation of the separator due to stress at the time of sealing.

  According to a tenth aspect of the present invention, in the fuel cell according to any one of the first to ninth aspects, the separator has a surface on both sides in the width direction of the seal groove and a width of the seal protrusion. The seal rubber layer is formed so as to spread on both sides in the direction, and the surface of the separator is also covered with the seal rubber layer at the bottom of the seal groove.

  In the fuel cell having the structure according to this aspect, even when the tip end surface of the seal protrusion is pressed against the bottom surface of the seal groove, it is effective for the problem that the separator is damaged by the pressure by the pressing. Therefore, a more reliable sealing mechanism can be realized. Even when a corrosive environment is formed between the opposing surfaces of the tip surface of the seal protrusion and the bottom surface of the seal groove, the bottom surface of the seal groove is covered with the seal rubber layer, so that the separator is corroded. It can be effectively avoided. Moreover, generation | occurrence | production of the burr | flash etc. at the time of shaping | molding of a seal groove | channel can also be prevented.

  An eleventh aspect of the present invention is the fuel cell according to any one of the first to tenth aspects, wherein the protruding height of the seal protrusion is the seal rubber in which the seal groove is formed. It is characterized by being 75 to 125% of the thickness dimension of the layer.

  In the fuel cell having the structure according to this aspect, the inclined surfaces on both sides in the width direction of the seal protrusion are sufficiently pressed against the inclined surfaces on both sides in the width direction of the seal groove, thereby improving the sealing performance. It can be fully demonstrated.

  A twelfth aspect of the present invention is the fuel cell according to any one of the first to eleventh aspects, wherein 50 to 125% of a thickness dimension of the seal rubber layer in which the seal groove is formed. The seal rubber layer is formed on the base end portion of the seal protrusion with a thickness dimension of.

  As is clear from the above description, in the fuel cell having the structure according to the present invention, the fluid between all the separators stacked on each other in the fuel cell having a stacked structure of a large number of fuel cells. High density can be achieved with high reliability with a small number of parts and a simple structure.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows a schematic perspective view of a polymer electrolyte fuel cell (PEFC) 10 having a structure according to the present invention. Such a polymer electrolyte fuel cell 10 is constituted by assembling a large number of single cells 12 as fuel cells having a structure according to the present invention in a stacked state. The polymer electrolyte fuel cell 10 shown in FIG. 1 is installed so that the vertical direction and the horizontal direction in the illustrated state are the vertical direction and the horizontal direction. In the following description, the vertical and horizontal directions, and the vertical and horizontal directions refer to the installation conditions shown in FIG.

  More specifically, as shown in FIG. 2, the unit cell 12 constituting the polymer electrolyte fuel cell 10 includes a solid polymer membrane 14 as a solid polymer electrolyte membrane such as a solid ion exchange membrane. And a membrane / electrode assembly (MEA) 18 having a structure in which a fuel electrode 16a and an oxidation electrode 16b as a pair of catalyst electrodes are overlapped and integrated on both surfaces. In this embodiment, the solid polymer film 14, the fuel electrode 16a, and the oxidation electrode 16b are all rectangular flat plate shapes, and the solid polymer film 14 is in front of the fuel electrode 16a and the oxidation electrode 16b. In the membrane / electrode assembly 18 in which the areas are viewed, the solid polymer membrane 14 extends outward from the fuel electrode 16a and the oxidation electrode 16b over the entire circumference. Yes. Specifically, for example, the solid polymer film 14 is a square of 82 mm × 82 mm in a front view, and the fuel electrode 16 a and the oxidation electrode 16 b are a square of 78 mm × 78 mm. The molecular film 14 is superposed and fixed so as to extend 2 mm outward from the electrodes 16a and 16b.

  In addition, the fuel electrode 16a and the oxidation electrode 16b have platinum as a catalyst as is well known, and are formed with a porous structure that allows gas to pass through, for example, a conductive material such as carbon. However, the material of the membrane / electrode assembly (MEA) 18 including the fuel electrode 16a and the oxidation electrode 16b, including the material of the solid polymer membrane 14, the structure in the micro region, etc. Since any known technique can be applied instead of the characteristic part, detailed description is omitted here.

  A pair of separators 20 and 22 are superimposed on the membrane / electrode assembly 18 so as to be sandwiched. In the present embodiment, the separator that is superimposed on the fuel electrode 16a side is referred to as the first separator 20, and the separator that is superimposed on the oxidation electrode side is referred to as the second separator 22. In the present embodiment, the same metal separator 24 as shown in FIGS. 3 to 5 is employed as the first separator 20 and the second separator 22.

  The metal separator 24 is formed of a metal material having effective rigidity and corrosion resistance under an oxidizing atmosphere in addition to good conductivity. For example, stainless steel is used as a basic material, and if necessary. A material that can achieve the required characteristics to a high degree by subjecting it to a surface treatment or a composite material with carbon or the like is preferably employed. The metal separator 24 is a flat metal plate having a substantially constant thickness dimension (for example, a thickness dimension of about 0.1 mm to 0.5 mm) so that the required rigidity and processing accuracy can be satisfied. Is formed by press working. In particular, in this embodiment, the metal separator 24 is formed using a metal plate having a thickness dimension of 0.3 mm.

  Specifically, the metal separator 24 has the same number (this embodiment) located on the first edge portion 26 and the second edge portion 28 that are positioned on the same side when the single cell 12 is configured. In the embodiment, three through holes 30a, 30b, 30c, 30d, 30e, and 30f are formed by punching. The three through holes 30a, 30e, and 30d in the first edge portion 30 and the three through holes 30c, 30f, and 30b in the second edge portion 28 are formed with symmetrical shapes and positions. Yes. That is, even when the metal separator 24 is turned upside down around any center axis of the horizontal center axis extending horizontally in the height direction center of the metal separator 24 and the vertical center axis extending vertically in the width direction center, A total of six through-holes 30a to 30f are positioned at the same position on the left and right side edge portions. The first edge portion 26 is formed with through holes 30a, 30e, and 30d in order from the top, while the second edge portion 28 is formed with through holes 30c, 30f, and 30b in order from the top. ing.

  As a result, when the two metal separators 24 and 24 are turned upside down and overlapped, each of the three through holes formed in the left and right edge portions communicates with each other in the overlapping direction. It is supposed to be squeezed. In the present embodiment, in the first separator 20, the through holes 30a, 30b, 30c, 30d, 30e, and 30f in FIGS. 3 and 4 are respectively the fuel gas supply hole 30a, the fuel gas discharge hole 30b, and the oxidizing gas supply. A hole 30c, an oxidizing gas discharge hole 30d, a cooling water supply hole 30e, and a cooling water discharge hole 30f are provided.

  Further, in the metal separator 24, the main surface 34 superimposed on the fuel electrode 16a has a fuel gas supply formed at the upper left portion of the first edge portion 26 as shown in FIGS. It extends in the horizontal direction from the vicinity of the hole 30a toward the second edge portion 28, bends vertically downward and extends slightly downward near the second edge portion 28, and further makes a U-turn to make the first edge. It extends in the horizontal direction toward the portion 26, bends vertically downward and extends slightly downward near the first edge portion 26, and again makes a U-turn and extends in the horizontal direction toward the second edge portion 28. A bent groove 32 for gas circulation that is bent and reaches the fuel gas discharge hole 30b formed in the lower right portion of the second edge portion 28 is formed. The concave groove 32 connects one through-hole 30 to another through-hole 30 opposed in a substantially diagonal direction. In particular, in the present embodiment, a plurality of ( In the present embodiment, five are formed. In particular, it is desirable that the concave groove 32 be formed so that each straight line portion extending in the horizontal direction is positioned at a substantially constant interval in the vertical direction of the main surface 34.

  In particular, in this embodiment, the groove 32 has a substantially isosceles trapezoidal cross-sectional shape in which the groove width gradually decreases toward the bottom surface, and has a substantially constant cross-sectional shape over the entire length. The groove 32 preferably has a groove width of 1.0 mm to 3.0 mm at the opening, 0.5 mm to 1.5 mm at the bottom, and a groove depth of 0.5 mm to 1.5 mm. More preferably, the groove width of the opening is 2.0 mm, the groove width of the bottom is 1.0 mm, and the groove depth is 1.0 mm. Further, in the groove 32 formed in a plurality of strips, the interval between the adjacent grooves 32 is preferably 0.5 mm to 1.5 mm at the opening, and more preferably 1.0 mm. Is desirable.

  In addition, a gas diffusion region in which a region formed on the main surface 34 of the metal separator 24 excluding a connection portion with the through holes 30 a to 30 d of the concave groove 32 is overlapped with the membrane / electrode assembly 18. 36. As shown in FIG. 4, a main surface sealing rubber layer 38 is vulcanized and deposited around the gas diffusion region 36 so as to surround the gas diffusion region 36. Sealing of the diffusion region 36 is realized.

  Further, on the main surface 34 of the metallic separator 24, a part of the concave groove 32 formed outside the gas diffusion region 36, that is, connection to the through holes 30a, 30b, 30c, 30d of the concave groove 32 is provided. A cover plate fitting 42 formed of a metal plate material is assembled in a bridging manner so as to cover the opening of the connection portion which is a part. In other words, the connection portion, which is a connection portion of the concave groove 32 to the through holes 30a to 30d, has a substantially tunnel-like structure by covering the opening of the concave groove 32 with the cover plate fitting 42. A main surface seal rubber layer 38 is also formed on the lid plate fitting 42.

  On the other hand, in the metallic separator 24, a concave passage 48 is formed on the sub-surface 46 opposite to the main surface 34 where the concave groove 32 opens, as shown in FIG. The concave passage 48 is formed in the sub-surface 46 between the plurality of concave grooves 32 formed in the main surface 34, and extends from the vicinity of the fuel gas supply hole 30a to the vicinity of the fuel gas discharge hole 30b. That is, in the first separator 20, the convex portion between the concave grooves 32 in the main surface 34 is used as the concave passage 48 in the opposite sub surface 46, and the oxidizing gas supply hole 30 c and the oxidizing gas discharge hole 30 d are formed. It extends along the concave groove 32 to the near side. In this embodiment, the concave passage 48 is filled with seal rubber at both ends in the vicinity of the fuel gas supply hole 30a and the fuel gas discharge hole 30b, and the concave passage 48 has the fuel gas supply hole 30a and the fuel gas discharge hole. It is not connected to 30b.

  Further, a connection recess 50 is formed near the cooling water supply hole 30e and the cooling water discharge hole 30f. The connection recess 50 has one end connected to the cooling water supply hole 30e or the cooling water discharge hole 30f, and the other end extending to the vicinity of the fuel gas supply hole 30a or the fuel gas discharge hole 30b. Yes.

  As shown in FIG. 5, on the substantially entire surface of the sub-surface 46 except for the portion near the outer periphery of the metallic separator 24 and the portion where the bottoms of the grooves 32 are brought into direct contact with each other in the assembled state, A sub surface sealing rubber layer 52 is formed. The sub-surface seal rubber layer 52 is preferably also formed on the inner surface of the concave passage 48, and the concave passage 48 is electrically insulated from the outside over substantially the entire length.

  Further, as shown in FIG. 6, a positioning portion 58 is formed on the outer surface of the main surface sealing rubber layer 38, that is, on the outer peripheral edge portion of the metallic separator 24 over substantially the entire circumference. The positioning portions 58 are formed of resin, and the positioning portions 58 formed on the adjacent metal separators 24 are formed so as to have concavo-convex shapes that engage with each other. In the polymer electrolyte fuel cell 10 formed by stacking the layers, the metal separators 24 can be easily aligned.

  In addition, as shown in FIG. 6, the outer peripheral edge of the metallic separator 24 on which the positioning portion 58 is deposited is formed on the main periphery in which the concave groove 32 is formed substantially over the entire circumference. The groove 34 is open to the surface 34 side. Thereby, the strength of the metal separator 24 can be increased and the positioning portion 58 can be more firmly fixed.

  Then, the membrane / electrode assembly 18 is sandwiched between the first separator 20 and the second separator 22 using such a metal separator, and each of the first separator 20 and the second separator 22 with respect to the membrane / electrode assembly 18. The single cell 12 is formed by the main surfaces 34 and 34 being overlapped. Further, the opening of the groove 32 for gas circulation formed in the first separator 20 is covered with the fuel electrode 16a, so that a fuel gas channel 60 for supplying fuel (hydrogen) is formed in a tunnel shape. Has been. Furthermore, the opening of the groove 32 for gas flow formed in the second separator 22 is covered with the oxidation electrode 16b, so that an oxidation gas flow path 62 for supplying oxygen (air) is formed in a tunnel shape. Has been. Furthermore, between the two adjacent single cells 12 and 12 that constitute a cell stack by being overlapped, the first separator 20 of one single cell 12 and the second separator 22 of the other single cell 12 are arranged. A cooling water flow path 64 through which cooling water flows is formed between the overlapping surfaces. The first separator 20 and the second separator 22 are configured by the same metal separator 24 that is overlapped so as to be opposite to each other. While the gas supply hole 30a and the fuel gas discharge hole 30b are connected, in the second separator 22, the oxidation gas supply hole 30c and the oxidation gas discharge hole 30d are connected by the concave groove 32. ing.

  Further, each single cell 12 is located at each of the upper and lower portions of the first edge portion 26 and the second edge portion 28 that are opposed to each other in the horizontal direction under the installed state of the polymer electrolyte fuel cell 10. A fuel gas supply hole 30a, a fuel gas discharge hole 30b, an oxidant gas supply hole 30c, and an oxidant gas discharge hole 30d are each formed penetrating in the stacking direction. In particular, the oxidizing gas supply hole 30c is formed so that the fuel gas supply hole 30a and the fuel gas discharge hole 30b are formed so as to be substantially opposed to each other in one diagonal direction and to be substantially opposed to each other in the diagonal direction. And an oxidizing gas discharge hole 30d.

  Moreover, in each center part of the 1st edge part 26 and the 2nd edge part 28 in each single cell 12, the cooling water supply hole 30e and the cooling water discharge hole 30f are opposing positions in a horizontal direction, respectively, It is formed to penetrate in the stacking direction.

  The supply holes 30a, 30c, 30e and the discharge holes 30b, 30d, 30f as described above are formed, for example, within a range of 18 mm from the first edge portion 26 or the second edge portion 28. In the embodiment, it is formed in a portion within 14 mm.

  Further, in each single cell 12, the membrane / electrode assembly 18 has a rectangular plate shape that is slightly smaller than the first and second separators 20 and 22. Specifically, for example, the first separator 20 and the second separator 22 have a substantially rectangular shape of 118 mm × 114 mm when viewed from the front, and the solid polymer film 14 has a square of 82 mm × 82 mm when viewed from the front. .

  Thereby, each supply-and-discharge hole 30a-f of fuel gas, oxidizing gas, and cooling water is each corresponding part of the 1st and 2nd separators 20 and 22 in the position which removed the membrane / electrode assembly 18 to the outer peripheral side. Each is formed as a through hole. In the polymer electrolyte fuel cell 10, the plurality of stacked single cells 12 are also communicated with each other, and as a whole, the cell stack that forms the main body of the polymer electrolyte fuel cell 10 is arranged in the stacking direction. The fuel gas, oxidant gas, and cooling water supply / discharge holes 30a to 30f are formed in a penetrating form.

  Although not explicitly shown in the drawings, a plurality of unit cells stacked in the polymer electrolyte fuel cell 10 are described as described in, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2002-83610). 12, the first separator 20 of the single cell 12 positioned at one end in the stacking direction and the second separator 22 of the single cell 12 positioned at the other end in the stacking direction The side current collecting plate and the cathode side current collecting plate are overlapped, and the total power of the plurality of single cells 12 connected in series is taken out from both the current collecting plates. Furthermore, the anode side pressing plate 66 and the cathode side pressing plate 68 are overlapped on the outer surfaces of the anode side current collecting plate and the cathode side current collecting plate via appropriate insulating spacers (not shown). Although not clearly shown in the drawing, the whole including the plurality of single cells 12 and the current collector plates and the holding plates 66 and 68 of both poles is tightened in the stacking direction by tightening bolts inserted at four corners. Are integrally fixed to form a polymer electrolyte fuel cell 10.

  In the polymer electrolyte fuel cell 10, the anode side retainer plate 66 and the cathode side retainer plate 68 are provided with a fuel gas supply port 70 a, a fuel gas discharge port 70 b, an oxidant gas supply port 70 c, and an oxidant gas discharge. A total of six ports 70a to 70f are formed including a port 70d for cooling, a port 70e for supplying cooling water, and a port 70f for discharging cooling water. Further, these respective ports 70a to 70f are respectively connected to the corresponding holes of the fuel gas, oxidizing gas and cooling water supply / discharge holes 30a to 30f formed in communication with each other in the plurality of stacked single cells 12. Are connected to each other. Further, by connecting external pipes (not shown) to the ports 70a to 70f, the fuel gas, the oxidizing gas, and the cooling water are supplied to the fuel gas, the oxidizing gas, and the cooling water supply / discharge holes 30a to 30f. It is designed to supply and discharge.

  The fuel gas, the oxidizing gas, and the cooling water supplied to the supply holes 30a, 30c, and 30e through the supply ports 70a, 70c, and 70e are the fuel gas flow paths 60 formed in the unit cell 12 described above. And the oxidant gas flow path 62 and the cooling water flow path 64 formed between the single cells 12 and 12, and then passed through the discharge holes 30b, 30d, and 30f and through the discharge ports 70b, 70d, and 70f. It is supposed to be discharged.

  Thus, as is well known, in the fuel electrode 16a disposed on the first separator 20 side of the solid polymer film 14, the supplied fuel gas is ionized by the catalytic action to supply electrons, while the solid polymer film 14 in the oxidation electrode 16b disposed on the second separator 22 side, the hydrogen ions sent through the solid polymer film 14 are supplied from the outside with the oxidizing gas (air) and the electrons returned through the external electric circuit, It reacts to produce water vapor and functions as a battery that exhibits power generation as a whole.

  Here, in order to efficiently achieve the target power generation action, the fuel gas and the oxidant gas continuously supplied to each single cell 12 are reacted without leaking from the gas diffusion region 36 to the outside. In addition to obtaining the action, it is necessary to circulate the cooling water continuously supplied to each single cell 12 without leaking, and to stably realize the temperature management of the single cell 12.

  Therefore, in the present embodiment, as described above, the main surface sealing rubber layer 38 formed so as to surround the gas diffusion region 36 and the through hole 30 is attached to the main surface 34 side of the metallic separator 24. At the same time, a sub surface seal rubber layer 52 is formed on the sub surface 46 side of the metallic separator 24 so as to surround the cooling water flow path 64.

  The main surface sealing rubber layer 38 is a substantially sheet-like rubber layer formed so as to surround the gas diffusion region 36 and the through-hole 30 over the entire circumference, and the main surface sealing rubber formed on the first separator 20. Seal ridges 72 are formed on the layer 38 a so as to surround the gas diffusion region 36 (membrane / electrode assembly 18) and the through-hole 30 over the entire circumference, while being attached to the second separator 22. A seal groove 74 is formed at a position corresponding to the seal protrusion 72 in a state of being overlapped with the first separator 20 with respect to the main surface seal rubber layer 38b. The thickness dimension of the main surface sealing rubber layer 38a is desirably 50% or more and 125% or less of the thickness dimension of the main surface sealing rubber layer 38b. In particular, in this embodiment, the main surface sealing rubber layer 38a The main surface sealing rubber layer 38b is formed with substantially the same thickness.

  As shown in FIGS. 7 and 8, the seal protrusion 72 has a substantially constant trapezoidal cross-sectional shape. In particular, in this embodiment, the seal projection 72 has a substantially isosceles trapezoidal shape in which the cross-sectional shape is gradually narrowed toward the protruding tip side, and has a symmetrical shape. Moreover, it is desirable that the inclination angle of the inclined surfaces on both sides in the width direction of the seal protrusion 72 is 20 degrees or more and 70 degrees or less. It should be noted that it is desirable to appropriately chamfer the portion where the corner is formed in the seal ridge 72 in order to avoid breakage and the like.

  On the other hand, the seal groove 74 has a substantially constant trapezoidal cross section as shown in FIGS. In particular, in this embodiment, the seal groove 74 is gradually widened toward the opening side, and both side wall surfaces of the seal groove 74 are formed of inclined surfaces. Further, as shown in FIG. 8, the cross-sectional shape of the seal concave groove 74 has a symmetrical shape. In addition, similarly to the seal protrusion 72, it is desirable to appropriately chamfer the portion where the corner is formed in the seal groove 74 in order to avoid breakage and the like. Further, the bottom surface of the seal groove 74 is formed of a rubber elastic body formed integrally with the main surface seal rubber layer 38b, and the second separator 22 is also covered with the rubber elastic body on the bottom surface of the seal groove 74. It is desirable. Thereby, malfunctions, such as a failure | damage by the contact to the 2nd separator 22 of the seal protrusion 72, can be avoided effectively.

In addition, the difference in inclination angle between both sides in the width direction of the seal ridge 72 and the seal groove 74 is desirably ± 10 degrees or less. In this embodiment, the side wall surface of the seal ridge 72 and the groove 32 The inclination angles of the side wall surfaces are substantially equal. The width dimension of the projecting distal end portion of the seal ridge 72: width of the bottom of the B ₁ is the groove 32: with is larger than W1, the width dimension of the base end portion of the seal ridge 72: B ₂ is width dimension of the opening of the groove 32: while being larger than W2, the width of the projecting distal end portion of the seal ridge 72: width of the opening of B ₁ is the groove 32: the smaller than W ₂ ing.

In addition, it is desirable for the seal protrusion 72 to have a width dimension B ₁ of the protruding tip portion of 0.1 mm ≦ B ₁ ≦ 0.4 mm, and more preferably 0.2 mm ≦ B ₁ ≦. 0.3 mm. The width dimension of the base end portion of the seal ridge 72: B ₂ is desirably being a 0.2mm ≦ B ₂ ≦ 0.6mm, more preferably, 0.3mm ≦ B ₂ ≦ 0. It is 5 mm. Furthermore, it is desirable that the projecting height dimension H of the seal protrusion 72 is 50% or more and 125% or less with respect to the thickness dimension of the main seal rubber layer 38b attached to the second separator 22. More preferably, the protruding height dimension H of the seal protrusion 72 is 75% or more and 125% or less with respect to the thickness dimension of the main surface seal rubber layer 38b attached to the second separator 22. More preferably, the protruding height dimension H of the seal protrusion 72 is substantially equal to the thickness dimension of the main seal rubber layer 38b. In particular, the seal protrusion 72 in this embodiment has a width at the protruding tip: B ₁ = 0.25 mm, a width at the base end: B ₂ = 0.4 mm, and a protruding height: H = 0.25 mm. Has been.

On the other hand, the width of the bottom of the seal groove 74: W ₁ is preferably 0.05 mm ≦ W ₁ ≦ 0.3 mm, and more preferably 0.1 mm ≦ W ₁ ≦ 0.2 mm. It is said that. The width dimension of the opening of the seal groove 74: W ₂ is desirably being a 0.1mm ≦ W ₂ ≦ 0.5mm, more preferably, 0.2mm ≦ W ₂ ≦ 0.4mm It is said that. Further, it is desirable that the depth dimension D of the seal concave groove 74 is 80% or more of the thickness dimension of the main seal rubber layer 38b formed on the second separator. In particular, the seal concave groove 74 in this embodiment has a bottom width dimension: W ₁ = 0.162 mm, an opening width dimension: W ₂ = 0.3 mm, and a depth dimension: D = 0.2 mm.

The seal ridges 72 and the seal grooves 74 are sealed in the single cell 12 by inserting the seal ridges 72 into the seal grooves 74 between the overlapping surfaces of the first separator 20 and the second separator 22. Has come to be demonstrated. That is, the inclination angle of the side wall surface of the seal protrusion 72 and the side wall surface of the seal groove 74 is substantially the same, and the width dimension B ₁ of the protruding tip of the seal protrusion 72 is the bottom of the seal groove 74. The width dimension of the seal ridge 72 is smaller than W ₁ , so that the inclined surfaces on both sides of the seal protrusion 72 are brought into pressure contact with the inclined surfaces on both sides of the seal groove 74. A seal mechanism that effectively exhibits a sealing effect by the engagement of the groove 74 is configured. In this embodiment, the outer peripheral portion of the solid polymer film 14 is sandwiched between the main surface sealing rubber layers 38a and 38b, and the solid polymer film 14 is held under pressure between the main surface sealing rubber layers 38a and 38b. Thus, a sealing effect can be effectively obtained.

  According to such a sealing mechanism, the component force of the assembly force that acts in the overlapping direction of the first separator 20 and the second separator 22 is on both side surfaces in the width direction of the seal protrusion 72 and the seal groove 74. The inclined surface acts as a sealing force. Such component force is smaller than the assembling force, and accordingly, variation in sealing force can be reduced. Further, since the seal protrusion 72 is pressed against the seal groove 74 on the inclined surfaces which are both side surfaces in the width direction of the seal protrusion 72 and the seal groove 74, the seal protrusion 72 and the seal groove 74 are compressed and deformed. At the same time, shear deformation occurs. Therefore, even when the distance between the opposing surfaces of the first separator 20 and the second separator is different, the sealing force generated between both side surfaces in the width direction of the seal protrusion 72 and the seal groove 74 is stably exhibited. .

In order to obtain a sufficient sealing effect, the compression margin area in the longitudinal section: S ₁ + S ₂ is 10% or more and 40% or less with respect to the area of the trapezoid ADHE in the longitudinal section: S ₃ . It is desirable. In particular, in order to exert the sealing performance advantageously, it is desirable that the ratio is approximately 25%. The compression allowance is preferably 25% in the thickness direction of the rubber seal when the lid is covered and one side is a seal rubber with a normal rubber seal and the other is a rigid body. In this embodiment, however, the compression allowance depends on the generated seal stress (pressing force). In order to avoid the influence of the metal separator 24 being deformed or the like, the compression allowance was set to 12.5%, which is half. However, in this embodiment, since both the seal ridge 72 and the seal groove 74 are formed of a rubber elastic body, the seal ridge 72 and the dimension at the time of design are shown in the longitudinal section shown in FIG. By setting the area (S ₁ + S ₂ ) of the overlapping portion of the seal groove 74 to approximately 25%, the seal protrusion 72 and the seal groove 74 are compressed by approximately 12.5%, respectively.

In addition, in the cross-sectional view of the sealing mechanism according to the present embodiment shown in FIG. 8, the sum of the area of trapezoid ABFE that is the compression margin: S ₁ and the area of trapezoid CDHG: S ₂ is the area of trapezoid ADHE: S ₃ and the area of the trapezoid BCGF: can be obtained by the difference of S _4.
(1) Area of trapezoid ADHE: S ₃
S ₃ = {(AD + HE) / 2} × (0.25-0.05)
= [{(0.075 / 0.25) × 0.2 × 2 + 0.25} / 2] × 0.2
= 0.0620
(2) Trapezoid BCGF area: S ₄
S ₄ = {(BC + GF) / 2} × (0.25−0.05)
= [{0.30 + {(0.025 / 0.225) × 0.069 × 2 + 0.162}} / 2] × 0.2
≒ 0.0477
(3) Area of trapezoid ABFE: Area of S ₁ and trapezoid CDHG: Sum of S ₂ S ₁ + S ₂ = (S ₃ −S ₄ ) ≈0.0620−0.0477 = 0.0143

Further, from the numerical values of S ₁ , S ₂ , and S ₃ , the area of the compression allowance in the present embodiment: the ratio of the trapezoidal ADHE of S ₁ + S ₂ to the ratio of S ₃ : {(S ₁ + S ₂ ) / S ₃ } × 100 (%) can be obtained.
That is, the area of the compression allowance in this embodiment is
(4) Area of compression allowance: Area of S ₁ + S ₂ trapezoid ADHE: ratio to S ₃ {(S ₁ + S ₂ ) / S ₃ } × 100≈ (0.0143 / 0.0620) × 100
≒ 23.1 (%)
It is said that.

Further, in the present embodiment, the width of the projecting tip of the seal ridge 72: B ₁ is smaller than the width of the opening of the seal groove 74: W ₂ , so that the seal ridge 72 is easy. It is inserted into the seal groove 74.

  By the way, in the present embodiment, the seal protrusion 72 and the seal groove 74 are formed on the main surface seal rubber layer 38 fixed to the main surface 34 side of the separator 24 to constitute a seal mechanism. 5, for the sub surface seal rubber layer 52 fixed to the sub surface 46 side, a seal ditch 76 is provided for the sub surface seal rubber layer 52 a fixed to the first separator 20. While being formed, a seal protrusion 78 is formed on the sub-surface seal rubber layer 52b fixed to the second separator 22, and a seal mechanism for preventing leakage of cooling water is configured.

  The seal protrusion 78 and the seal groove 76 formed on the side of the sub surface 46 are formed so as to surround the periphery of the cooling water flow path 64 and the through holes 30a to 30f formed on the sub surface 46, respectively. . The seal protrusions 78 and the seal grooves 76 formed integrally with the sub surface seal rubber layer 52 are the seal protrusions 72 and seal grooves 74 formed integrally with the main surface seal rubber layer 38 described above, Since the cross-sectional shape and dimensions have substantially the same structure, and the principle that the sealing effect is exhibited in the assembled state is also the same, detailed description is omitted to avoid redundant description. .

  In the polymer electrolyte fuel cell 10 having the structure according to this embodiment, the main surface sealing rubber layer 38 a and the main surface sealing rubber layer 38 b are overlapped between the overlapping surfaces of the first separator 20 and the second separator 22. The seal ridges 72 formed in the main surface seal rubber layer 38a are press-fitted into the seal concave grooves 74 formed in the main surface seal rubber layer 38b, thereby the main surface seal rubber layer 38a and the main surface seal rubber layer 38b. The subsurface seal rubber layer 52a and the subsurface seal rubber layer 52b are overlapped to form a seal protrusion 82 formed on the subsurface seal rubber layer 52b. By being press-fitted into the seal concave groove 76 formed in 52a, there is a flow between the opposing surfaces of the sub surface seal rubber layer 52a and the sub surface seal rubber layer 52b. It is tightly sealed. Thereby, problems such as a decrease in power generation efficiency due to leakage of fuel gas, oxidizing gas, and cooling water can be advantageously avoided, and the performance of the fuel cell 10 can be improved.

  In particular, in the polymer electrolyte fuel cell 10 having the structure according to the present embodiment, the first separator 20 is likely to cause a problem when an assembly force is applied in the stacking direction in a state where a large number of single cells 12 are stacked. The difference in sealing performance due to the variation in the distance between the opposing surfaces of the second separator 22 is made relatively small. That is, both side surfaces in the width direction of the seal ridges 72 (78) are both inclined surfaces inclined at substantially the same inclination angle, and both side surfaces in the width direction of the seal grooves 74 (76) are both. Since the inclined surface is inclined at substantially the same inclination angle as both side surfaces in the width direction of the seal protrusion 72 (78), the sealing performance is exhibited by the component force of the compressive force acting in the overlapping direction. Compared to the case where the assembly force is applied directly and the sealing effect is exerted, the difference in the sealing performance when the applied assembly force is different is suppressed. -ing

  Further, since the solid polymer film 14 is sandwiched between the main surface sealing rubber layer 38a fixed to the first separator and the main surface sealing rubber layer 38b fixed to the second separator, the main surface sealing rubber layer 38a, As shown in FIG. 8, a gap is generated between 38 b, and the protruding tip end surface of the seal protrusion 72 and the bottom surface of the seal groove 74 are positioned apart from each other. Therefore, when the seal protrusion 72 and the seal groove 74 are elastically deformed by press-fitting the seal protrusion 72 into the seal groove 74, the base end portion of the seal protrusion 72 and the opening portion of the seal groove 74 are formed. Rubber that is elastically deformed and is sandwiched between the opposed surfaces of the main seal rubber layers 38a and 38b, and the space between the opposed surfaces of the projecting tip surface of the seal protrusion 72 and the bottom surface of the seal groove 74 is bulged and deformed. By being filled with the elastic body, a uniform seal surface is formed on both side walls in the width direction of the seal protrusion 72 and the seal groove 74, and the seal performance on the main surface 34 side can be obtained more advantageously.

  FIG. 9 is a cross-sectional view of a seal mechanism (the seal ridge 82 and the seal groove 84 in the assembled state), which is a main part of the polymer electrolyte fuel cell according to the second embodiment of the present invention. Has been. In the following description, members or portions that are substantially the same as those in the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof is omitted.

  In the polymer electrolyte fuel cell according to the present embodiment, the main surface seal rubber layer 76a is formed with seal ridges 82 extending in a substantially semicircular fixed cross section. More specifically, the seal ridge 82 is formed so as to surround the gas diffusion region 36 and the through hole 30 respectively, as in the first embodiment. In addition, as for the seal protrusion 82, it is desirable for the diameter in the cross section to be 0.3 mm or more and 0.6 mm or less, and it is set as the substantially semicircle shape with a diameter of 0.45 mm in this embodiment. Further, in the seal protrusion 82 in the present embodiment, the semicircular portion is integrally formed with a step having a height of 0.05 mm and protruding from the main surface seal rubber layer 76a. Yes. Further, a fillet radius having a radius of 0.05 mm is formed over the entire length on both side surfaces of the step, and the seal protrusion 82 is smoothly connected to the main surface seal rubber layer 76a. Thereby, the seal protrusion 82 in this embodiment has a height dimension of 0.23 mm. The width of the base end of the seal protrusion 82 is desirably larger than the width of the opening of a seal groove (84) described later, and in this embodiment, it is preferably 0.45 mm. Has been. As is clear from the fact that the seal protrusion 82 in the present embodiment has a substantially semicircular cross-sectional shape, the surface including both side surfaces in the width direction is a substantially curved inclined surface that protrudes outward. It is comprised.

  In the polymer electrolyte fuel cell according to the present embodiment, the seal concave groove 84 is formed in the main surface seal rubber layer 76b. The seal groove 84 is formed to extend in a trapezoidal cross-sectional shape, and has a shape that gradually expands toward the opening side. In addition, the bottom surface of the seal groove 84 in the present embodiment is configured by the second separator 22. In short, the main seal rubber layer 76b is not formed on the bottom surface of the seal concave groove 84 in the present embodiment. In particular, in the seal groove 84 in this embodiment, the groove width dimension of the bottom surface is 0.20 mm, and the groove width dimension in the opening is 0.40 mm. In order to avoid metal corrosion of the second separator 22, it is desirable that the second separator 22 be made of a corrosion-resistant material or subjected to a corrosion-resistant film processing for preventing corrosion.

  Here, when the main surface 34 of the first separator 20 and the main surface 34 of the second separator 22 are overlapped with the membrane / electrode assembly 18 interposed therebetween, the main surface seal rubber layer 76a fixed to the first separator 20 is integrated. The formed seal protrusion 82 is press-fitted into the seal groove 84 formed in the main surface seal rubber layer 76 b fixed to the second separator 22. In particular, in this embodiment, the seal protrusion 82 is formed in a substantially semicircular cross section, and the seal groove 84 is formed in a groove shape having a substantially isosceles trapezoidal cross section. After being easily inserted into the groove 84 and after being inserted to a certain extent, a part of the surface of the seal protrusion 82 and the side wall surface of the seal groove 84 are brought into pressure contact with each other. It will be demonstrated effectively.

  In particular, in this embodiment, the width dimension of the base end portion of the seal protrusion 82 is made larger than the width dimension of the opening of the seal groove 84. Therefore, the sealing protrusion 82 can be press-fitted into the sealing groove 84 to surely exert the sealing effect.

  As mentioned above, although some embodiment of this invention has been described, this is an illustration to the last, Comprising: This invention is not limited at all by the specific description in this embodiment.

  For example, in the first embodiment, the seal protrusion 72 having an isosceles trapezoidal cross section is shown, and in the second embodiment, the seal protrusion 82 having a substantially semicircular cross section is shown, and the seal recess into which they are press-fitted. Although the example which made the groove | channels 74 and 84 into the isosceles trapezoid cross-sectional shape was shown, the seal | sticker protruding item | line is not limited at all by the specific description in these embodiment. Specifically, for example, both the side surfaces in the width direction of the seal protrusion and the seal groove are different from each other like the seal protrusion 86 shown in FIG. 10 and the seal groove 87 having a cross-sectional shape corresponding thereto. You may be comprised by the inclined surface which has an inclination angle.

  In the first and second embodiments, the seal grooves 74, 78, and 84 all have a groove shape having a trapezoidal cross section. However, the shape of the seal groove is the first and second embodiments. It is not limited at all by the specific description in the form. Specifically, for example, a groove shape having a substantially semicircular cross section may be used.

  The specific dimensions of the seal protrusions 72, 76, 82, the seal grooves 74, 78, 84, etc. in the first and second embodiments are suitable numerical values, and are limitedly interpreted. Is not to be done.

  In the first and second embodiments, the gas diffusion region 36 and the through hole 30 are each surrounded by a single strip of projecting ridge 72 (82) (sealing groove 74 (84)). A plurality of ridges 72 (82) and seal grooves 74 (84) may be formed. Thus, by forming the plurality of seal ridges 72, 72... And the seal grooves 74, 74..., A more reliable sealing effect can be obtained, effectively reducing the power generation efficiency. Can be prevented. Of course, a plurality of seal ridges 78 and seal grooves 76 formed on the sub-surface 46 side may be formed.

  In the first and second embodiments, the main surface seal rubber layer 38 a fixed to the first separator 20 is formed with the seal protrusion 72, and the main surface seal rubber layer fixed to the second separator 22. Although the example in which the seal groove 74 is formed in 38b is shown, the seal separator is formed on the second separator 22 side that forms the oxidizing gas channel 62, and the first separator 20 that forms the fuel gas channel. A seal groove 74 may be formed on the surface. Further, any of the seal protrusions 78 and the seal grooves 76 formed on the sub surface 46 side may be formed in the first separator 20. Further, it is not necessary to form only one of the seal protrusion 72 or the seal groove 74 on one separator. For example, gas diffusion is performed on the main surface seal rubber layer 38 fixed to one separator 24. The seal protrusion 72 may be formed so as to surround the region 36, and the seal groove 74 may be formed so as to surround the through hole 30.

  In the first and second embodiments, the seal protrusion 72 (82) formed on the main surface 34 side and the seal protrusion 76 formed on the sub surface 46 side have substantially the same cross-sectional shape. In addition, an example is shown in which the seal groove 74 (84) formed on the main surface 34 side and the seal groove 78 formed on the sub surface 46 side have substantially the same cross-sectional shape. The seal ridges 72 (82) and the seal grooves 74 (84) on the 34 side need not have the same shape as the seal ridges 76 and the seal grooves 78 on the sub-surface 46 side. Depending on the performance, the cross-sectional shape can be varied or the dimensions can be varied.

  In addition, the concave grooves 32 formed in the metal separator 24 desirably extend in a distorted manner as shown in the first and second embodiments, but are necessarily in such a shape. There is no need. Furthermore, the cross-sectional shape of the concave groove 32 is not limited to the shape described in the embodiment. Specifically, for example, a concave groove having a rectangular cross section may be employed.

  Furthermore, in the first and second embodiments, the first separator 20 and the second separator 22 are configured by the same metal separator 24, but the first separator 20 and the second separator 22 are not necessarily the same. It is not necessary to be comprised with the metal separator 24, and may be comprised with the separator which has a different shape. The separator is not necessarily made of metal, and may be any material that satisfies the required performance such as gas impermeability, conductivity, and corrosion resistance. Specifically, for example, various separators such as carbon and conductive resin can be used.

  In the embodiment, the cooling water channel 64 is formed by using the unevenness formed on the sub-surface 46 of the metal separator 24 by the concave groove 32. However, the cooling water channel 64 does not necessarily use such unevenness. It is not necessary to form. Furthermore, it is not necessary that the flow path has a substantially constant cross-sectional area, and it is only necessary that the cooling water supply hole 30e and the cooling water discharge hole 30f are connected on the sub-surface 46 so that the cooling water can flow.

  In addition, the fuel gas supply hole 30a and the fuel gas discharge hole b to which the concave groove 32 is connected, or the cooling water supply hole 30e and the cooling water discharge hole 30f to which the concave passage 48 is connected need not necessarily be one each. There is no. That is, a plurality of supply holes and discharge holes may be formed. In that case, a plurality of flow paths are formed so as to connect the holes. Needless to say, the same applies to the oxidizing gas supply hole 30c and the oxidizing gas discharge hole 30d.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

  Next, as an embodiment of the present invention, simulation result data will be shown to further clarify the present invention. In addition, it cannot be overemphasized that this invention does not receive any restrictions by description of the Example shown below. In addition to the examples described below, the present invention can be variously based on the knowledge of those skilled in the art without departing from the spirit of the present invention other than the description of the above-described embodiments. It should be understood that changes, modifications, improvements, etc. may be made.

  First, as a rubber material used for forming the main surface sealing rubber layer 38a fixed to the first separator 20 and the main surface sealing rubber layer 38b fixed to the second separator 22, in this embodiment, HS = 70. The simulation was carried out assuming that the ethylene-propylene rubber (EPDM) was adopted. The rubber material has a Young's modulus E of 5.096 MPa and a Poisson's ratio ν of the rubber material of 0.495. For the simulation in this example, simulation software capable of performing nonlinear calculation for a rubber material was used.

  Using such a rubber material, the main surface seal rubber layer 38 having the seal protrusion 72 and the seal groove 74 having a structure according to the present invention, and the main surface seal rubber layers 88 and 90 having a conventional seal structure as a comparison target. Respectively. In addition, the main surface sealing rubber layer 38 having a structure according to the present invention has the structure shown in the above-described embodiment, and the shape and dimensions thereof are in accordance with the shape and dimensions shown in the above-described embodiments. Further, as shown in FIG. 11, the main surface seal rubber layer 88 having a conventional seal structure is a seal ridge having a substantially semicircular cross-sectional shape on the main surface seal rubber layer 88a fixed to the first separator 20. On the other hand, the main surface sealing rubber layer 88b fixed to the second separator 22 has a substantially flat surface. Particularly in this embodiment, the seal projection 92 has a substantially semicircular cross section having a diameter of 0.3 mm. Further, as shown in FIG. 12, the main surface seal rubber layer 90 having a conventional seal structure has a cross-sectional shape in which the protruding tip portion is substantially semicircular to the main surface seal rubber layer 90a fixed to the first separator 20. In addition, a seal protrusion 94 having a substantially trapezoidal cross-sectional shape at the base end portion is formed, and a groove extending along the seal protrusion 94 is formed on both sides of the seal protrusion 94. On the other hand, the main surface sealing rubber layer 90b fixed to the second separator 22 is a substantially flat surface. In particular, in this embodiment, the projecting height dimension of the seal protrusion 94 is 0.15 mm, and the projecting tip portion has a semicircular cross-sectional shape having a diameter of 0.2 mm. Further, the recessed grooves formed on both sides of the seal protrusion 94 have a depth dimension of 0.1 mm and a bottom width dimension of 0.05 mm.

Then, in the assembled state, the stress distribution inside the main surface seal rubber layer 38 was measured in three states in which the total thickness of each main surface seal rubber layer 38 was T ₁ , T ₂ , and T ₃ , respectively. That is, by making the distance between the opposing surfaces of the main surface sealing rubber layer 38a and the main surface sealing rubber layer 38b different,
Condition (A): Thickness dimension: T ₁ = 0.550 mm
Condition (B): Thickness dimension: T ₂ = T ₁ −0.025 mm = 0.525 mm
Condition (C): Thickness dimension: T ₃ = T ₁ +0.025 mm = 0.575 mm
The stress distribution under the three conditions was measured. The measured data of the stress distribution under the conditions (A), (B), and (C) are shown in FIGS.

  Similarly, in the main surface sealing rubber layers 88a and 88b and the main surface sealing rubber layers 90a and 90b, the stresses of the main surface sealing rubber layers 88a and 88b and the main surface sealing rubber layers 90a and 90b in three states having different thickness dimensions: T. The distribution was measured. 16, 17, and 18 show measured data of the stress distribution of the main seal rubber layers 88 a and 84 under the conditions (A), (B), and (C), and FIGS. The actual measurement data of the stress distribution of the main surface seal rubber layers 90a and 90b under the conditions (A), (B), and (C) are shown.

  According to FIGS. 13, 14, and 15, in the main surface seal rubber layers 38 a and 38 b according to the present invention, a part of the side wall surface of the seal protrusion 72 and the seal groove 74, that is, the seal protrusion 72 indicated by an arrow. The maximum value of stress was measured at the protruding tip. Specifically, as shown in FIG. 13, under condition (A), a stress value of 1.47 MPa was measured as the maximum value of stress near the protruding tip of the seal protrusion 72. Further, as shown in FIG. 14, under the condition (B), a stress value of 1.56 MPa was measured as the maximum stress value in the vicinity of the protruding tip of the seal protrusion 72. Furthermore, as shown in FIG. 15, under the condition (C), a stress value of 1.17 MPa was measured as the maximum stress value in the vicinity of the protruding tip of the seal protrusion 72.

  On the other hand, according to FIGS. 16, 17, and 18, in the main surface seal rubber layers 88a and 84 of the conventional structure, the maximum value of stress was measured inside the main surface seal rubber layer 88b against which the seal protrusion 92 was pressed. Specifically, as shown in FIG. 16, under the condition (A), a stress value of 1.55 MPa was measured as the maximum value of stress inside the main surface seal rubber layer 88b. Further, as shown in FIG. 17, under the condition (B), a stress value of 2.08 MPa was measured as the maximum value of stress inside the main surface sealing rubber layer 88b. Further, as shown in FIG. 18, under the condition (C), a stress value of 1.13 MPa was measured as the maximum value of stress inside the main surface sealing rubber layer 88b.

  Furthermore, according to FIGS. 19, 20, and 21, in the main surface seal rubber layers 90 a and 90 b of the conventional structure, the maximum value of stress was measured inside the seal protrusion 94. Specifically, as shown in FIG. 19, under the condition (A), a stress value of 1.74 MPa was measured as the maximum value of stress inside the seal protrusion 94. Further, as shown in FIG. 20, under the condition (B), a stress value of 2.26 MPa was measured as the maximum value of stress inside the seal protrusion 94. Furthermore, as shown in FIG. 21, under the condition (C), a stress value of 1.30 MPa was measured as the maximum value of stress inside the seal protrusion 94.

  From the measured data of the stress distribution described above, it has been proved that, in the main surface sealing rubber layers 38a and 38b having the structure according to the present invention, the variation in stress is minimized when the separation distance between the main surface sealing rubber layers is different.

  That is, in the main surface sealing rubber layer 38 having a structure according to the present invention, the difference between the maximum stress value in the condition (A) and the maximum stress value in the condition (B) is 0.09 MPa. Further, the difference between the maximum stress value in the condition (A): and the maximum stress value in the condition (C) is 0.30 MPa.

  On the other hand, in the main surface sealing rubber layer 88 having the conventional sealing mechanism, the difference between the maximum stress value in the condition (A) and the maximum stress value in the condition (B) is 0.53 MPa. Further, the difference between the maximum stress value in the condition (A): and the maximum stress value in the condition (C) is 0.42 MPa.

  On the other hand, in the main surface sealing rubber layer 90 having the conventional sealing mechanism, the difference between the maximum stress value in the condition (A) and the maximum stress value in the condition (B) is 0.52 MPa. Further, the difference between the maximum stress value in the condition (A): and the maximum stress value in the condition (C) is 0.44 MPa.

  As is clear from the above, the condition (A) in which the distance between the opposed surfaces of the main surface sealing rubber layer is the reference T1, and the distance between the opposed surfaces of the pair of main surface sealing rubber layers is 25 μm with respect to the condition (A). Three conditions: a condition (B) in which the distance between the opposing surfaces of the pair of main surface sealing rubber layers is separated from the condition (A) by 25 μm. In the simulation below, the main surface sealing rubber layer 38 having the structure according to the present invention has the smallest difference in the maximum stress value between the conditions. That is, in the main surface sealing rubber layer 38 (sealing mechanism) having the structure according to the present invention, even when the distance between the opposing surfaces of the pair of main surface sealing rubber layers 38a and 38b to be overlapped is different, the expected surface is stably obtained. It was proved by simulation that the sealing performance can be demonstrated.

  And according to FIGS. 16-21 which showed the simulation result of the sealing mechanism of the conventional structure, the maximum stress is not the sealing surface (the press contact portion of the sealing protrusion and the main surface sealing rubber layer), but the main surface sealing rubber layer 88b or It is generated inside the seal protrusion 94 formed on the main surface seal rubber layer 90a, and the generated stress cannot be used skillfully for the sealing effect, and in order to obtain a sufficient sealing effect, an excessive internal stress is required. This may cause adverse effects such as a decrease in durability due to the internal stress. On the other hand, according to the simulation results shown in FIGS. 13 to 15, in the sealing mechanism having the structure according to the present invention, the sealing surfaces (the both sides in the width direction of the seal protrusion 72 and the both sides in the width direction of the seal groove 74). It is clear that the maximum stress exhibited in the seal structure is skillfully utilized for the expression of the sealing effect. Therefore, the fuel cell 10 having such a sealing mechanism and having a structure according to the present invention can exhibit a sufficient sealing effect even when the compressive force applied in the overlapping direction is relatively small, and is excellent. Durability can also be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective explanatory view showing a polymer electrolyte fuel cell as a first embodiment of the present invention. FIG. 2 is a perspective explanatory view showing a single cell constituting the fuel cell shown in FIG. 1. It is the front view which showed the main surface of the metal separator which comprises the fuel cell shown by FIG. It is a front view which shows the state which adhere | attached and formed the main surface sealing rubber layer on the main surface of the metal separator shown by FIG. FIG. 5 is a front view showing a state in which a sub surface sealing rubber layer is formed on the sub surface of the metal separator shown in FIG. FIG. 2 is an enlarged longitudinal sectional view showing a positioning portion in an assembled state of single cells constituting the fuel cell shown in FIG. 1. FIG. 2 is an enlarged longitudinal sectional view showing a main surface sealing rubber layer in an assembled state of single cells constituting the fuel cell shown in FIG. 1. It is a longitudinal cross-sectional explanatory drawing which shows the principal part of the main surface sealing rubber layer shown by FIG. It is a longitudinal cross-sectional explanatory drawing which shows the principal part of the polymer electrolyte fuel cell as 2nd embodiment of this invention. It is a longitudinal cross-sectional explanatory drawing which shows the principal part of the polymer electrolyte fuel cell as another one Embodiment of this invention. It is longitudinal cross-sectional explanatory drawing which shows the main surface sealing rubber layer which has the sealing mechanism of the conventional structure as a comparison object. It is a longitudinal cross-sectional explanatory drawing which shows the main surface sealing rubber layer which has another conventional structure sealing mechanism as a comparison object. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example. It is a stress distribution figure which shows the measurement result of the stress distribution by the simulation as an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fuel cell 12 Single cell 14 Solid polymer membrane 16a Fuel electrode 16b Oxidation electrode 18 Membrane / electrode assembly 20 First separator 22 Second separator 36 Gas diffusion region 38a Main surface seal rubber layer 38b Main surface seal rubber layer 52 Sub surface seal rubber layer 72 Sealing ridge 74 Sealing groove 76 Sealing ridge 78 Sealing groove

Claims (12)

A fuel cell comprising a membrane / electrode assembly in which electrodes are disposed on both sides of a solid polymer electrolyte membrane to form a fuel cell by laminating the separator from both sides, and a fuel cell having a laminated structure in which a plurality of the fuel cells are further superimposed In
A sealing rubber layer is formed on each of the overlapping surfaces of the separators that are overlapped with each other, and a sealing groove having a cross-sectional shape that widens toward the opening side is formed on the sealing rubber layer on the overlapping surface of one of the separators. In addition, the seal rubber layer on the overlapping surface of the other separator is formed with a seal protrusion having a cross-sectional shape narrowing toward the front end side, and the seal protrusion is fitted into the seal groove. The fuel cell is characterized in that a sealing mechanism is constituted by the inclined surfaces on both sides in the width direction of the seal protrusion being pressed against the inclined surfaces on both sides in the width direction of the seal groove and being elastically deformed.   The sealing mechanism including the sealing groove and the sealing protrusion is provided so as to surround the membrane / electrode assembly on the overlapping surface of the separator that is overlapped with the membrane / electrode assembly interposed therebetween. The fuel cell according to claim 1.   Between the overlapping surfaces of the separators overlapped with each other, there is a gap between the opposing surfaces of the seal rubber layer, and there is also a gap between the bottom surface of the seal groove and the front end surface of the seal protrusion. The fuel cell according to claim 1, wherein the fuel cell is present.   4. The fuel cell according to claim 1, wherein each of the seal groove and the seal protrusion has a symmetrical cross-sectional shape. 5.   The difference between the inclination angle of the inclined surfaces on both sides in the width direction in the cross section of the seal groove and the inclination angle of the inclined surfaces on both sides in the width direction in the cross section of the seal protrusion is ± 10 degrees or less. 5. The fuel cell according to any one of 4 above.   The inclination angle of the inclined surfaces on both sides in the width direction in the cross section of the seal groove and the inclination angle of the inclined surfaces on both sides in the width direction in the cross section of the seal protrusion are both at least on the surface of the separator in a region pressed against each other. 6. The fuel cell according to claim 1, wherein the fuel cell is set to 20 degrees or more and 70 degrees or less.   The fuel cell according to any one of claims 1 to 6, wherein inclined surfaces on both sides in the width direction in the cross section of the seal protrusion are curved inclined surfaces that protrude outward.   The width of the opening in the seal groove is larger than the width of the tip of the seal ridge, and the width of the bottom of the seal groove is greater than the width of the tip of the seal ridge. The fuel cell according to claim 1, which is also made smaller.   The fuel cell according to any one of claims 1 to 8, wherein a compression allowance of the seal protrusion is 5 to 20% in a cross-sectional area between the overlapping surfaces of the separators.   On the surface of the separator, the seal rubber layer is formed so as to spread on both sides in the width direction of the seal groove and on both sides in the width direction of the seal protrusion, and the surface of the separator is also formed on the bottom surface of the seal groove. The fuel cell according to claim 1, which is coated with   11. The fuel cell according to claim 1, wherein a protruding height of the seal protrusion is 75 to 125% of a thickness of the seal rubber layer in which the seal groove is formed. 12. The seal rubber layer according to claim 1, wherein the seal rubber layer is formed at a base end portion of the seal protrusion with a thickness dimension of 50 to 125% of a thickness dimension of the seal rubber layer in which the seal groove is formed. 2. The fuel cell according to item 1.