JP2007141550A - Fuel cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel cell suppressing the flowing-out of a sealing member. <P>SOLUTION: The fuel cell is formed by alternately stacking a separator and a membrane electrode assembly. A plurality of through holes are installed in the thickness direction of the separator along each side on the plane of the separator, a manifold for reaction gas is formed on the inside of the fuel cell with the through holes of the stacked separator, and in stacking, the sealing member preventing leak of the reaction gas to the outside of the fuel cell is interposed, a seal line surrounding the through hole and having a shape different from the through hole is installed in the sealing member, and more than half of a part of the seal line, which is at least a part of of the seal line, formed between one side of the separator and one through hole corresponding to the one side is formed in a shape in which the distance from one side of the separator to the seal line is continuously changed in the one side direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a structure of a fuel cell, and more particularly to a seal structure that suppresses leakage of a reaction gas used in a fuel cell.

  Conventionally, various structures have been studied as fuel cells for vehicles. For example, a fuel cell called a solid polymer type is formed by laminating a plurality of single cells formed by arranging separators on both sides of a membrane electrode assembly (MEA) in which an electrode is joined to an electrolyte membrane of a solid polymer. A structure that is held under a predetermined pressure is a basic structure. Each separator is provided with a through-hole through which a reaction gas supplied from the outside passes, and a plurality of separators are stacked to form a manifold as a reaction gas flow path inside the fuel cell.

  As an example of a fuel cell having such a basic structure, Patent Document 1 below discloses a structure in which a separator formed by stacking three plates and a membrane electrode structure are stacked.

JP 2004-6104 A

  By the way, in such a fuel cell having a manifold inside, a seal member is interposed in the stacking process in order to suppress leakage of the reaction gas to the outside of the fuel cell. Such a seal member is fixed by a predetermined pressure at the time of assembly, but the seal member sometimes protrudes from the outer periphery of the fuel cell due to the pressure of the reaction gas flowing in the manifold. As a result, the sealing performance inside the fuel cell may be deteriorated.

  In order to deal with these problems, it is conceivable to provide a reinforcing frame on the outer periphery of the seal member, etc., so that the seal member does not protrude even when subjected to pressure in the manifold. As the number of fuel cells increases, the weight of the fuel cell itself increases, which is not realistic. Therefore, it has been desired to cope with the protrusion to the outer periphery depending on the structure of the seal member itself.

  An object of the present invention is to provide a fuel cell that suppresses the sticking of the sealing member in view of the problem that the sealing member protrudes.

  In view of the above problems, the fuel cell of the present invention employs the following method. That is, a fuel cell in which separators and membrane electrode assemblies are alternately stacked, and a plurality of through holes are provided in the thickness direction of the separator along each side on the plane of the separator. A plurality of reaction gas manifolds are formed inside the fuel cell by the through holes of the separator, and in the stacking, a seal member for suppressing leakage of the reaction gas to the outside of the fuel cell is interposed, The seal member is provided with a seal line that surrounds the through hole and has a shape different from that of the through hole, and is at least part of the seal line, and one side of the separator and one side of the through hole corresponding to the one side The majority of the part of the seal line formed between the separator and the separator is formed into a shape in which the distance from one side of the separator to the seal line continuously changes in the one side direction. It is the gist.

  According to the fuel cell of the present invention, the shape of the seal line that functions to suppress leakage of the reaction gas is different from the shape of the through hole, and the majority of the portion between the separator side and the through hole is sealed from the separator side. Forming into a shape in which the distance to the line continuously changes in one side direction. Of the seal line, the portion between one side of the separator and the through-hole receives a force in a direction protruding from the fuel cell or the outer periphery of the separator (force perpendicular to one side) due to the pressure of the reaction gas flowing through the through-hole. . In order to form such a part in a shape in which the distance changes continuously, the force in the direction perpendicular to one side is dispersed. Therefore, the seal line has a structure that is difficult to be deformed in a direction that protrudes from the outer periphery of the fuel cell or the separator, and can prevent the seal member from protruding due to the pressure of the reaction gas. As a result, the leakage of the reaction gas from the fuel cell can be appropriately suppressed.

  The shape in which the distance in the fuel cell having the above configuration continuously changes in one side direction may be a shape having a predetermined curvature in a direction perpendicular to one side of the separator.

  According to such a fuel cell, a shape having a predetermined curvature is adopted as a shape whose distance continuously changes in one side direction. That is, the seal line portion between one side of the separator and the through hole is formed not in a straight line parallel to the one side direction of the separator but in a curved shape. Therefore, the force in the direction protruding from the outer periphery of the separator is dispersed along the curvature, and the deformation of the seal member in the protruding direction can be suppressed. As a result, the leakage of the reaction gas from the fuel cell can be appropriately suppressed.

  The separator of the fuel cell having the above configuration is formed in a substantially rectangular plane, includes the substantially rectangular through hole, and the shape of the entire seal line having the predetermined curvature is substantially the same as that of the separator. The shape may be a substantially crescent shape that is convex in a direction perpendicular to one side of the rectangle.

  According to such a fuel cell, a substantially crescent-shaped seal line is formed with respect to the substantially rectangular through-hole, and the convex line of the substantially crescent moon is arranged in the vertical direction on one side of the separator. By forming a substantially crescent-shaped seal line in this direction, a force is exerted on the seal member in a direction perpendicular to the vertical direction on one side of the separator. With such a force, the seal member does not easily deform in the direction of protruding from the outer periphery of the separator, and the protrusion of the seal member due to the pressure of the reaction gas can be suppressed.

  The fuel cell having the above-described configuration is provided with a plurality of adjacent through holes for the same reactive gas along each side on the plane of the separator, and the seal member corresponds to each through hole. The seal line may be formed.

  According to such a fuel cell, a plurality of through holes are provided at adjacent locations along each side on the plane of the separator corresponding to the same reaction gas, and a seal line is provided for each through hole. By providing a seal line for each through-hole, a seal member exists between adjacent through-holes, and a structure in which the seal member hardly deforms in the direction of protruding from the outer periphery of the separator can be obtained.

  In the fuel cell having the above-described configuration, the separator is a three-layer stacked separator formed by stacking three conductive plates, and the seal member surrounds the membrane electrode assembly, and the membrane electrode joint The three-layer laminated separator and the integral membrane electrode assembly may be alternately laminated to form a single body.

  According to such a fuel cell, the seal member is integrally formed with the membrane electrode assembly, and a plurality of three-layer stacked separators and integral membrane electrode assemblies are alternately stacked to form a fuel cell. By making the seal member an integral structure, the number of parts can be reduced and the number of assembly steps can be reduced. In addition, by applying the structure of the seal member to a fuel cell composed of a three-layered separator in which the seal member may be protruded, a significant effect is obtained in suppressing the leakage of the reaction gas.

Embodiments of the present invention will be described in the following order based on examples.
A. Configuration of fuel cell system:
B. Seal line of the first embodiment:
C. Seal line of the second embodiment:
D. Variation:

A. Configuration of fuel cell system:
FIG. 1 is an explanatory diagram showing a schematic configuration of a fuel cell system including a fuel cell as one embodiment of the present invention. As shown in the figure, the fuel cell system 1 includes a fuel cell 10 that generates electricity by an electrochemical reaction between hydrogen and oxygen, a hydrogen tank 100 that supplies hydrogen gas to the fuel cell 10, and air that contains oxygen to the fuel cell 10. A compressor 110 for cooling, a radiator 120 for cooling the fuel cell 10, a battery 140 for storing electric power of the fuel cell 10, a traveling motor 160 driven by the electric power of the fuel cell 10 and the like are mounted on the vehicle.

  The fuel cell 10 is a polymer electrolyte fuel cell, and includes a terminal 34, an insulator 33, and an end plate 30 in order at both ends of a plurality of modules 20 having electrolyte membranes, electrodes, separators, and the like. The end plate 30 has supply ports and discharge ports for hydrogen, oxygen, cooling water, and the like, and includes a fastening portion for bolts 32 that are coupled to the tension plate 31. By connecting the end plates 30 at both ends of the plurality of stacked modules 20 with the tension plates 31 by the bolts 32, a predetermined compressive force is applied in the stacking direction of the modules 20. The separator is provided with a plurality of through holes in the thickness direction, and a plurality of modules 20 are stacked to form a plurality of manifolds. The position of each manifold corresponds to the position of the supply / discharge port of the end plate 30, and various fluids from the outside are supplied to each module 20 without stagnation. The detailed structure of the module 20 and the separator will be described later.

  The hydrogen tank 100 is a supply source that supplies hydrogen gas to the fuel cell 10 thus formed, and stores high-pressure hydrogen gas. The hydrogen tank 100 and the fuel cell 10 are connected by a hydrogen supply pipe 104, and high-pressure hydrogen gas from the hydrogen tank 100 is decompressed to a predetermined pressure by a pressure reducing valve 102 provided on the hydrogen supply pipe 104 and fuel It is supplied into the battery 10. The supplied hydrogen gas is used for the above reaction and cannot be used for the reaction. A part of the hydrogen gas discharged from the hydrogen discharge pipe 106 is supplied by a circulation pump 108 provided on the hydrogen discharge pipe 106. Circulated to the side.

  The compressor 110 is a supply source that supplies air to the fuel cell 10, sucks air in the atmosphere, and supplies this to the fuel cell 10. The compressor 100 and the fuel cell 10 are connected by an air supply pipe 112, and air from the outside is supplied into the fuel cell 10 through the air supply pipe 112. The supplied air is used for the above reaction, and the gas after the reaction is discharged from the air discharge pipe 115 to the outside.

  The reaction by the hydrogen gas and air supplied in this way is an exothermic reaction. The radiator 120 and the fuel cell 10 are connected to each other by a cooling water supply pipe 121 and a cooling water discharge pipe 122. By circulating the cooling water through the radiator 120, a temperature rise in the fuel cell 10 is within a predetermined range. In. The cooling water is circulated by driving a pump 125 provided on the cooling water supply pipe 121.

  The electric power generated by the reaction in the fuel cell 10 is stored in the battery 140 via the DC / DC converter 130 and used for the rotational power of the travel motor 160 via the inverter 150.

  FIG. 2 is a cross-sectional view showing a schematic structure of the module 20 of the fuel cell 10. This sectional view shows a section obtained by cutting the module 20 having a predetermined thickness on a substantially rectangular surface in the thickness direction. As shown in the drawing, the module 20 includes a single cell 40 and a part of separators 50 arranged at both ends thereof. The unit cell 40 includes an MEA (membrane electrode assembly) 42 including an electrolyte membrane, second gas diffusion layers 44 and 46 disposed outside the MEA 42, and a seal member 48 that mainly covers the outer periphery of the MEA 42. And these are integrally formed.

  The MEA 42 includes electrodes (anode and cathode) on the surface of the electrolyte membrane, which is a thin film, and includes a first gas diffusion layer outside each electrode. The electrolyte membrane is made of a solid polymer material having proton conductivity and exhibits good electrical conductivity in a wet state. The electrode includes a catalyst that promotes an electrochemical reaction, such as platinum. The first gas diffusion layer is a carbon porous body, and is formed of, for example, carbon cloth or carbon paper. Each part made of such a material is integrated by bonding to form MEA 42.

  The second gas diffusion layers 44 and 46 are formed of a metal porous body having a large number of pores therein, such as foam metal or metal mesh. The space formed by the internal pores functions as a flow path for air and hydrogen gas in the single cell 40. That is, the second gas diffusion layer 44 is disposed in the space between the cathode side of the MEA 42 and the separator 50 and functions as an air flow path, and the second gas diffusion layer 46 is disposed in the space between the anode side of the MEA 42 and the separator 50. Arranged to serve as a hydrogen gas flow path. Air and hydrogen gas supplied to the flow path made of the porous material are diffused to the respective surfaces of the MEA 42 in the process of flowing through the flow path. The air and hydrogen gas supplied to the MEA 42 are diffused by the first gas diffusion layer, reach the respective electrodes, and react via the electrolyte membrane. Hereinafter, a structure in which the MEA 42 includes the second gas diffusion layers 44 and 46 is referred to as MEGA 47.

  FIG. 3 is a perspective view showing a part of the seal member 48 covering the outer periphery of the MEGA 47. The seal member 48 is formed of an insulating resin material having elasticity such as silicon rubber, butyl rubber, or fluorine rubber, and is integrated with the MEGA 47 as illustrated. Specifically, the seal member 48 is injection-molded on the outer periphery of the MEGA 47, and is integrated with the MEGA 47 by impregnating the insulating resin material into the gaps of the porous body. Thus, the seal member 48 is joined to the MEGA 47 without any gap. Hereinafter, the unit cell 40 having such a configuration is referred to as a MEGA 47 having an integrated seal structure.

  The seal member 48 is formed with a convex portion covering the manifold hole in the fuel cell 10 in the thickness direction, and a hole corresponding to the manifold hole is formed in the inner region surrounded by the convex portion. ing. When such a seal-integrated MEGA 47 and separator 50 are alternately stacked and a compressive force in the stacking direction by the tension plate 31 is applied, the convex portion of the seal member 48 comes into contact with two adjacent separators 50 in the stacking direction. Crush and deform. As a result, the convex portion forms a seal line SL that suppresses leakage of reaction gas (air, hydrogen gas) from the inside of the manifold.

  As described above, the fuel cell 10 according to the present embodiment is formed by alternately stacking the MEGA 47 and the separator 50 having an integrated seal structure. That is, the seal member 48 is sandwiched and fixed between two adjacent separators 50, and there is no need to provide a resin frame or the like having higher rigidity than the seal member 48 between the separators 50. Therefore, the number of parts can be reduced and the volume and weight of the fuel cell 10 can be reduced.

  Next, the detailed structure of the separator 50 will be described. As shown in FIG. 2, the separator 50 includes a cathode side plate 52 that contacts the second gas diffusion layer 44 that serves as an air flow path, and an anode side that contacts the second gas diffusion layer 46 that serves as a hydrogen gas flow path. There are three plates: a plate 54 and an intermediate plate 53 disposed between the two plates. The separator 50 has a three-layer structure in which these plates are stacked in the order of a cathode side plate 52, an intermediate plate 53, and an anode side plate 54. The separator 50 having such a structure is called a three-layer stacked separator.

  FIG. 4 is an explanatory view showing a planar shape of the cathode side plate 52. As shown in the figure, the cathode side plate 52 is formed in a substantially rectangular outer shape, and includes six substantially rectangular through holes 60a to 65a along four sides of the rectangle. Specifically, a through hole 60a for supplying air (denoted as air in in the drawing) is provided along one of the two long sides of the rectangle, and for discharging air along the other side (in the drawing). (Referred to as “air out”). Further, along one of the two short sides, a through hole 65a for supplying hydrogen gas (denoted as hydrogen in) and a through hole 63a for discharging cooling water (denoted as water out) are provided. Along with, a through hole 62a for supplying cooling water (denoted as water in) and a through hole 64a for discharging hydrogen gas (denoted as hydrogen out) are provided.

  Further, the cathode side plate 52 includes a plurality of substantially circular holes 55 and 56 at positions moved by a predetermined distance from the air through holes 60a and 61a toward the center of the cathode side plate 52. That is, the plurality of holes 55 and 56 are arranged side by side in the long side direction of the cathode side plate 52, the hole 55 corresponds to the through hole 60a, and the hole 56 corresponds to the through hole 61a. The holes 55 and 56 also function as part of the air flow path, and the air flow will be described later.

  FIG. 5 is an explanatory view showing a planar shape of the anode side plate 54. As shown in the figure, the anode side plate 54 is formed in a substantially rectangular outer shape that is the same as the cathode side plate 52, and includes through holes 60 b to 65 b having the same shape at the same position as the cathode side plate 52. The anode side plate 54 includes a plurality of substantially circular holes 57 and 58 at positions moved from the through holes 62b and 63b for hydrogen gas by a predetermined distance in the center direction of the anode side plate 54. That is, the plurality of holes 57 and 58 are arranged side by side in the short side direction of the anode side plate 54, the hole 57 corresponds to the through hole 65b, and the hole 58 corresponds to the through hole 64b.

  FIG. 6 is an explanatory view showing the planar shape of the intermediate plate 53. As shown in the figure, the intermediate plate 53 is formed in the same substantially rectangular outer shape as the cathode side plate 52. The intermediate plate 53 includes an air supply through portion 60c along one of the two long sides and an air discharge through portion 61c along the other side. The air supply through portion 60 c is formed in a shape in which the through hole 60 a and the hole 55 of the cathode side plate 52 are joined together, and the air discharge through portion 61 c is formed of the through hole 61 a and the hole 56 of the cathode side plate 52. It is formed in a shape that joins together.

  The intermediate plate 53 includes a through-hole 64c for discharging hydrogen gas along one of the two short sides and a through-hole 65c for supplying hydrogen gas along the other side. Similar to the air penetration part, the hydrogen gas discharge penetration part 64c is formed to connect the through hole 64b and the hole 58 of the anode side plate 54, and the hydrogen gas supply penetration part 65c The through hole 65b and the hole 57 of the anode side plate 54 are connected to each other.

  Further, the intermediate plate 53 has an elongated hole portion 66 that connects the positions of the through holes 62a and 62b for supplying cooling water and the positions of the through holes 63a and 63b for discharging cooling water shown in FIGS. There are several. The hole 66 is formed in a linear shape in the long side direction in the vicinity of the approximate center of the intermediate plate 53, and both ends of the straight portion have the size of the through holes 62a, 62b, 63a, 63b for cooling water. It is formed diagonally to fit.

  These three plates having a planar shape have a flat surface with no irregularities such as a flow path, and are made of a conductive metal material such as stainless steel, titanium, or a titanium alloy. By separating and joining these plates, the separator 50 is completed. 4, 5, and 6 correspond to the cross-sectional shape of the separator 50 illustrated in FIG. 2.

  By using such MEGA 47 in which separators 50 are formed by laminating such flat plates and the flow path is formed of a porous body, it is not necessary to form a flow path groove by a complicated manufacturing method such as etching. Note that the material of the plate constituting the separator 50 may be a resin material having conductivity.

  In the completed separator 50, flow paths for various fluids are formed by overlapping the through holes, and a manifold is formed inside the fuel cell 10 by stacking a plurality of such separators 50. Hereinafter, the manifold formed by the through holes 60a and the like is the air supply manifold 60, the manifold formed by the through holes 61a and the like is the air discharge manifold 61, and the manifold formed by the through holes 65a and the like is the hydrogen supply manifold 65, A manifold formed by the through holes 64a and the like is a hydrogen discharge manifold 64, a manifold formed by the through holes 62a and the like is a cooling water supply manifold 62, a manifold formed by the through holes 63a and the like is a cooling water discharge manifold 63, Each will be called.

  Next, the flow of fluid in the separator 50 having such a structure will be described. The air flowing through the air supply manifold 60, that is, the air supplied to the through hole 60a of the cathode side plate 52 of the separator 50 (air flowing from the front side to the back side of the paper surface of FIG. 4) is the through portion 60c of the intermediate plate 53. , And flows through the through hole 60 b of the anode side plate 54, and a part thereof flows through the hole 55 of the cathode side plate 52 by the through portion 60 c of the intermediate plate 53. That is, air flows through the hole 55 in FIG. 4 from the back side to the front side. Thus, the air flowing on the surface of the separator 50 (the surface of the cathode side plate 52) flows in the second gas diffusion layer 44 of the MEGA 47 adjacent to the separator 50, and flows into the holes 56 of the cathode side plate 52 while being subjected to the reaction. (The hole 56 in FIG. 4 flows from the front side to the back side of the paper surface). Then, the through-hole 61 c of the intermediate plate 53 merges with the air flowing through the through-hole 61 b of the anode-side plate 54 and the through-hole 61 c of the intermediate plate 53 (air flowing through the air discharge manifold 61). The through hole 61a flows toward the front side of the paper surface of FIG.

  The hydrogen gas is almost the same as the air flow. Through the through portions 64 c and 65 c of the intermediate plate 53, the hydrogen gas moves from the hole 57 to the hole 58 on the surface of the anode side plate 54, and The gas flows in the two-gas diffusion layer 46 and is subjected to the reaction. The cooling water circulates through the hole 66 of the intermediate plate 53 without any delay.

  The reaction gas in the manifold formed by stacking a plurality of the separators 50 flows with a pressure of about 100 kPa. Therefore, the internal pressure in the manifold acts on the seal line SL between the separators 50. With this internal pressure, the seal line SL (seal member 48) tends to be deformed in the expanding direction. That is, it tries to deform in a direction that protrudes from the outer periphery of the separator 50. In this embodiment, the shape of the seal line SL itself prevents the seal member 48 from protruding from the outer periphery of the separator 50. Hereinafter, the shape of such a seal line SL will be described.

B. Seal line of the first embodiment:
FIG. 7 is an explanatory view showing a planar shape of the MEGA 47 having a seal-integrated structure as the first embodiment. As shown in the figure, the MEGA 47 having an integrated seal structure has a substantially rectangular outer shape that is the same as each plate of the separator 50, and the seal member 48 that covers the outer periphery of the MEGA 47 has positions corresponding to the manifolds 60 to 65. Holes 60d to 65d having a size are provided. A seal line SL is provided as a part of the seal member and around each of the holes 60d to 65d.

  Usually, the shape of the seal line is formed in accordance with the shape of the manifold. For example, if the manifold is rectangular, the seal line is also rectangular. In contrast, in this embodiment, as shown in FIG. 7, a seal line is formed with a substantially crescent shape different from the manifold hole shape with respect to the substantially rectangular manifold hole (through hole of the separator). ing.

  This seal line SL covers a substantially rectangular manifold hole, and is a portion of the seal line SL formed between one side of the outer periphery of the seal member 48 (the outer periphery of the separator 50) and the corresponding one through hole. Is formed with a predetermined curvature in a direction perpendicular to one side of the outer periphery, and is formed in a substantially crescent shape as a whole. Taking the air supply manifold 60 as an example, a seal line SL formed between the one side α of the outer periphery of the illustrated seal member 48 and the hole 60d of the seal member 48 is a curve that is convex in the Y direction in the figure. Forming. That is, the seal line SL is formed in a substantially crescent shape that is convex in the Y direction. The Y direction shown in the figure indicates a direction perpendicular to one side α of the outer periphery of the seal member 48 (short side direction of the seal member 48 having a substantially rectangular outer shape), and the X direction is parallel to one side α of the outer periphery of the seal member 48. Direction (long side direction of the seal member 48).

  Such a substantially crescent-shaped seal line SL is provided around each manifold hole, that is, each of the illustrated holes 60d to 65d, and is perpendicular to each side of the outer periphery of the seal member 48 from the center of the MEGA 47 having an integrated seal structure. It is formed to be convex.

  FIG. 8 is an enlarged view showing the shape of the seal line SL near one manifold. The seal line SL shown in the figure is an enlarged view of the hole 60d (hole corresponding to the air supply manifold 60) of the seal member 48 shown in FIG. 7, the Y direction in the drawing indicates the short side direction of the seal member 48, and the X direction indicates the long side direction of the seal member 48.

  As shown in the drawing, when air of a predetermined pressure is supplied to the air supply manifold 60, air flows through the hole 60d of the seal member 48 sandwiched between the separators 50, and air pressure is applied to the seal line SL. This pressure acts equally on each part of the substantially crescent-shaped seal line SL, and works in the direction of expanding the seal line SL.

  As described above, the seal member 48 including the seal line SL is made of an insulating resin material having elasticity, and has lower rigidity than the MEGA 47 including the MEA 42. That is, a portion near the MEGA 47 side in the seal line SL is hardly deformed due to the influence of the rigidity of the MEGA 47. As a result, the seal line SL receiving the pressure tends to deform exclusively in the Y direction (the direction in which the seal member 48 protrudes from the outer periphery of the separator 50).

  Since the seal line SL of the present embodiment is formed in a substantially crescent shape having a predetermined curvature on the outer peripheral side of the separator 50, the seal line SL receives a force to be deformed in the Y direction by pressure and also receives a force in the X direction. . In other words, the force in the direction in which the seal member 48 protrudes from the outer periphery of the separator 50 is dispersed to generate the force F in the direction orthogonal to the direction in which the seal member 48 protrudes (see FIG. 8). The seal member 48 is pulled by the force F in the orthogonal direction, and the deformation in the direction protruding from the outer periphery of the separator 50 is suppressed.

  Although the seal line SL portion close to the MEGA 47 side is hardly deformed as described above, a compressive force in the X direction acts on the seal member 48 on the MEGA 47 side due to the substantially crescent-shaped recess. Therefore, it can be set as the structure which cannot change easily to a Y direction according to the shape of a seal line.

  Further, the seal line SL of the present embodiment has a predetermined curvature on the outer peripheral side of the separator 50, and the distance in the Y direction from the outer periphery of the separator 50 to the seal line SL varies continuously in the X direction. ing. That is, the margin in the Y direction is thicker near both ends of the seal line SL that is long in the X direction than in the vicinity of the center. Therefore, the ease of deformation in the Y direction at each portion of the seal line SL in the X direction is different, and there is no large deformation due to continuous displacement as in the case where the seal line is formed linearly.

  By adopting the seal line SL having such a shape, it is possible to prevent the seal member 48 from protruding from the outer periphery of the separator 50 due to the pressure of the reaction gas. As a result, leakage of the reaction gas from the fuel cell 10 can be appropriately suppressed.

  In particular, when the seal line SL having such a shape is employed in a fuel cell having a configuration in which a seal member is sandwiched between separators and the seal member is held by a compressive force in a module stacking direction, the effect is great. By using the seal line SL having such a shape to improve the reliability of the seal member, there is no need to adopt a member or configuration for preventing deformation (displacement) of the seal member, the number of parts is reduced, and the structure is improved. While simplifying, the volume and weight of the whole fuel cell can be reduced. As a result, manufacturing costs can be reduced and mass productivity can be improved.

  In the first embodiment described above, the substantially crescent-shaped seal line SL that protrudes from the center in a direction perpendicular to each side of the outer periphery of the seal member 48 is formed. A substantially crescent-shaped seal line that is concave in the direction may be formed.

  Specifically, as shown in FIG. 9, a substantially crescent-shaped seal line SL <b> 2 in which the convex direction of FIG. 7 is reversed is formed. When pressure is applied to the seal line SL2 having such a shape, the force in the direction in which the seal member 48a protrudes from the outer periphery of the separator 50 is dispersed to generate a force in a direction perpendicular to the direction in which the seal member 48a protrudes (for example, the force F2 shown in the figure). Let The force in the orthogonal direction compresses the seal member 48a and suppresses deformation in the direction protruding from the outer periphery of the separator 50.

  Further, the margin in the Y direction is longer in the vicinity of the center of the seal line SL2 that is longer in the X direction than in the vicinity of both ends. Therefore, a large deformation due to continuous displacement does not occur as in the case where the seal line is formed linearly. Therefore, the sticking out of the seal member 48a can be suppressed, and the leakage of the reaction gas from the fuel cell 10 can be appropriately suppressed.

C. Seal line of the second embodiment:
FIG. 10 is an explanatory view showing a planar shape of the MEGA 47 having a seal-integrated structure as the second embodiment. As shown in the drawing, the MEGA 47 portion of the second embodiment is the same as the MEGA 47 portion of the first embodiment shown in FIG. 7, and the shape of the seal member including the seal line is different. Accordingly, only the parts different from the first embodiment will be described with the seal member as the center.

  As shown in the drawing, the substantially rectangular seal member 48b includes holes 62d to 65d having the same positions and sizes as the holes 62d to 65d for hydrogen and cooling water shown in FIG. For the sake of simplicity, the same reference numerals as those in FIG. 7 are used.

  Further, the seal member 48b has a total of six holes 71 to 76 obtained by dividing the two air holes 60d and 61d shown in FIG. A substantially crescent-shaped seal line SL3 protruding in the outer peripheral direction of the separator is provided as a part of the seal member 48b and around each of the holes 62d to 65d and 71 to 76. That is, in the second embodiment, the three holes 71, 72, 73 function as the holes 60d as the air supply path in the first embodiment, and the three holes 74, 75, 76 serve as the air discharge path. Acts as a hole 61d. In addition, although illustration is abbreviate | omitted, the separator of 2nd Example is a three-layer lamination type separator substantially the same as the separator 50 of 1st Example, and the shape of the through-hole for air differs. That is, a plurality of through holes for air are provided corresponding to FIG. 10, and a fuel cell is formed by including a total of ten manifolds obtained by dividing the air manifolds 60 and 61 of the first embodiment into three equal parts. Has been.

  Thus, when pressure is applied to the seal line SL3 formed around each manifold (each hole 62d to 65d, 71 to 76), the force in the direction in which the seal member 48b protrudes from the outer periphery of the separator is dispersed as in the first embodiment. The protrusion of the sealing member 48b from the outer periphery of the separator is suppressed.

  Further, three substantially crescent-shaped seal lines SL3 are arranged side by side in one long side direction of the seal member 48b. Since each seal line SL3 forms a closed region independently, a seal member 48b exists between adjacent seal lines SL3 (see part B in FIG. 10). Such a portion (B portion) serves as a reinforcement (so-called rib) that suppresses deformation from the outer periphery of the separator into a protruding square. Therefore, the seal member 48b can be prevented from protruding from the outer periphery of the separator, and the leakage of the reaction gas from the inside of the fuel cell can be appropriately suppressed.

  In this embodiment, since the air manifolds 60 and 61 of the first embodiment are divided, the total opening area of the manifold is reduced. In such a case, the shape of the manifold hole may be set in accordance with the shape of the seal line SL3, and an opening area capable of supplying an amount of reaction gas necessary for the reaction in the fuel cell may be ensured. That is, the shape of the manifold hole is set so as to be within the region inside the substantially crescent-shaped seal line. By doing so, the seal line of the second embodiment can be adopted while securing a necessary and sufficient opening area, and a fuel cell with a small volume can be formed.

  In this embodiment, the air manifold is formed by a plurality of adjacent through holes, and the seal line SL3 is provided for each through hole. However, the hydrogen manifold is formed by a plurality of adjacent through holes. It is also good. Further, the cooling water manifold may be formed by a plurality of adjacent through holes. That is, the same reaction gas flow path such as air and hydrogen including cooling water is formed by a plurality of adjacent manifolds. Almost the same pressure acts in adjacent manifolds of the same reaction gas. For such a separator (fuel cell), by using the seal member formed with the seal line shape of the present embodiment, it is possible to suppress the protrusion of the seal member from the outer periphery of the separator.

D. Variation:
Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and can of course be implemented in various forms without departing from the spirit of the present invention. .

  In this embodiment, the seal line is described as being formed in a substantially crescent shape. However, the present invention is not limited to this, and the seal line is formed between one side of the separator outer periphery and one corresponding through hole. This portion may have any shape as long as the distance from one side of the outer periphery of the separator to the seal line continuously changes in the direction of the one side.

  Specifically, as shown in FIGS. 11A to 11D, a seal line may be formed in a semicircular shape, a triangular shape, an elliptical shape, or a circular shape. FIG. 11 shows the shape of the seal line for one through hole, and the broken line inside the seal line indicates the shape of the through hole of the separator.

  By forming the seal line in the shape shown in FIG. 11, the force in the direction in which the seal member protrudes from the outer periphery of the separator due to the pressure is dispersed, the protrusion of the seal member is suppressed, and the leakage of the reaction gas from the inside of the fuel cell is appropriately performed. Can be suppressed.

  In this embodiment, the seal member provided with the seal line has been described as having an integral structure together with the MEGA. However, the seal member does not necessarily have to be an integral structure. For example, the seal line shape of the present invention can be adopted even when the seal member is formed in a frame shape covering the MEGA and the seal member as an individual component is sandwiched between the separators.

  Furthermore, in the present embodiment, the separator having a flat surface in contact with the MEGA has been described as an example, but the seal line shape of the present invention can be adopted even with a separator having a channel groove. . In this case, for example, the fuel cell is formed by sandwiching the MEA excluding the second gas diffusion layer functioning as a porous body flow path with a separator having a flow path uneven groove on the surface. A seal member formed in a frame shape covering the MEA is sandwiched between the separator and the MEA, and, for example, a substantially crescent-shaped seal line is provided on the seal member. By doing so, it is possible to suppress the seal member from protruding from the outer periphery of the separator, and appropriately suppress the leakage of the reaction gas to the outside of the fuel cell.

It is explanatory drawing which shows schematic structure of the fuel cell system containing the fuel cell of this invention. It is sectional drawing which shows schematic structure of the module of a fuel cell. It is a perspective view which shows a part of sealing member which covers the outer periphery of MEGA. It is explanatory drawing which shows the planar shape of a cathode side plate. It is explanatory drawing which shows the planar shape of an anode side plate. It is explanatory drawing which shows the planar shape of an intermediate | middle plate. It is explanatory drawing which shows the planar shape of MEGA of the seal integrated structure of 1st Example. It is an enlarged view which shows the shape of the seal line SL near one manifold. It is explanatory drawing which shows the planar shape of MEGA of the seal integrated structure of the modification of 1st Example. It is explanatory drawing which shows the planar shape of MEGA of the seal integrated structure of 2nd Example. It is explanatory drawing which shows the shape of the seal line as a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system 10 ... Fuel cell 20 ... Module 30 ... End plate 31 ... Tension plate 32 ... Bolt 33 ... Insulator 34 ... Terminal 40 ... Single cell 42 ... MEA
44, 46 ... second gas diffusion layer 47 ... MEGA
48, 48a, 48b ... seal member 50 ... separator 52 ... cathode side plate 53 ... intermediate plate 54 ... anode side plate 55, 56, 57, 58 ... hole 60a, 61a, 62a, 63a, 64a, 65a ... through hole 60b, 61b, 62b, 63b, 64b, 65b ... through hole 60c, 61c, 64c, 65c ... through portion 60 ... air supply manifold 61 ... air discharge manifold 62 ... cooling water supply manifold 63 ... cooling water discharge manifold 64 ... hydrogen discharge manifold 65 ... Hydrogen supply manifold 60d, 61d, 62d, 63d, 64d, 65d ... Hole 66 ... Hole 71, 72, 73 ... Hole 74, 75, 76 ... Hole 100 ... Hydrogen tank 102 ... Pressure reducing valve 104 ... Hydrogen supply pipe 106 ... Hydrogen discharge pipe 108 ... circulation pump 110 ... co Presser 112 ... air supply pipe 115 ... air discharge pipe 120 ... radiator 121 ... cooling water supply pipe 122 ... cooling water discharge pipe 125 ... pump 130 ... DC / DC converter 140 ... battery 150 ... inverter 160 ... traveling motor

Claims (5)

A fuel cell in which separators and membrane electrode assemblies are alternately laminated,
A plurality of through holes are provided in the thickness direction of the separator along each side on the plane of the separator,
By forming through holes in the stacked separator, a reaction gas manifold is formed inside the fuel cell,
In the stacking, a seal member that suppresses leakage of the reaction gas to the outside of the fuel cell is interposed,
The seal member surrounds the through hole, and is provided with a seal line having a shape different from the through hole,
A majority of the part of the seal line, which is at least part of the seal line and formed between one side of the separator and the one through hole corresponding to the one side, extends from one side of the separator to the seal line. A fuel cell formed into a shape in which the distance up to continuously changes in the one side direction. The fuel cell according to claim 1,
The shape in which the distance continuously changes in the one side direction is a fuel cell having a predetermined curvature in a direction perpendicular to one side of the separator. The fuel cell according to claim 2, wherein
The separator is formed in a substantially rectangular plane and includes the substantially rectangular through hole,
The shape of the entire seal line having the predetermined curvature is a fuel cell having a substantially crescent shape protruding in a direction perpendicular to one side of the substantially rectangular shape of the separator. A fuel cell according to any one of claims 1 to 3,
Along each side on the plane of the separator, a plurality of adjacent through holes are provided for the same reactive gas,
A fuel cell in which the seal line corresponding to each through hole is formed in the seal member. A fuel cell according to any one of claims 1 to 4,
The separator is a three-layer stacked separator formed by stacking three conductive plates,
The seal member surrounds the membrane electrode assembly and is configured integrally with the membrane electrode assembly;
A fuel cell formed by alternately laminating a plurality of the three-layer stacked separators and the integral membrane electrode assembly.

Images