Metallic porous body for a fuel cell

Abstract

A metallic porous body (10) for a fuel cell formed by stacking a plurality of unit cells consisting of a metallic porous body (10), the metallic porous body (10) comprising: a porous portion (11) in contact with a reactive region of a membrane electrode assembly (40) and corresponding to a reactive region of each unit cell; a flat portion (12) having a flat surface structure formed along the outer edges of the metallic porous body (10) which does not correspond to the porous portion (11) constituting the reactive region, wherein the metallic porous body (10) is a gas diffusion layer, and wherein the planar portion (12) is integrated with a gasket (20) such that the gasket (20) is integrally connected to the metallic porous body (10), and the planar portion (12) has through holes (14) formed at positions where the gasket (20) is molded, so that the metallic porous body (10) is firmly integrated with the gasket (20) molded on both sides of the planar portion (12) by a resin to function as a gasket (20) introduced into the through holes (14).

Description

Background(a) Technical area

[0001] The present invention relates to a metallic porous body for a fuel cell. More specifically, the present invention relates to a metallic porous body for a fuel cell that has improved handling and operational properties and can be stacked accurately and precisely, thereby also improving the productivity of a fuel cell stack. (b) State of the art

[0002] A fuel cell is a system for generating electrical energy that, instead of converting the chemical energy of a fuel into heat through combustion, converts the chemical energy electrochemically directly into electrical energy in a fuel cell stack. Fuel cells can be used as an electrical power source for small electrical and electronic devices, including portable devices, industrial applications, household appliances, and vehicles.

[0003] One of the most commonly used fuel cells, particularly for vehicles, is a proton exchange membrane fuel cell or polymer electrolyte membrane fuel cell (PEMFC). It consists of a fuel cell stack including a membrane electrode assembly (MEA), a gas diffusion layer (GDL), a gasket, a sealing member, and a bipolar plate (separator). Generally, the MEA includes a polymer electrolyte membrane through which hydrogen ions are transported, and an electrode / catalyst layer, where an electrochemical reaction takes place, is arranged on either side of the polymer electrolyte membrane. The GDL serves to evenly distribute the gaseous reactants and conduct the generated electricity. The gasket serves to provide airtightness suitable for the gaseous reactants and the coolant.The sealing part serves to provide the appropriate pressure for the connection. Finally, the bipolar plate serves to support the MEA and the GDL, collect and conduct the generated electricity, conduct the gaseous reactants, conduct and remove the reaction products, and conduct the coolant to dissipate the reaction heat, etc.

[0004] The GDL is bonded to the outer surface of the electrode / catalyst layer deposited on the surface of the polymer electrolyte membrane, forming an anode (“fuel electrode”) and a cathode (“air electrode” or “oxygen electrode”), and serves to supply hydrogen and air (oxygen) as gaseous reactants, transfer the electrons generated by the electrochemical reaction, and remove the reaction product water to minimize flooding in the fuel cell.

[0005] Recently, intensive research has been carried out worldwide on the application of a thin metal plate with a mesh structure instead of a carbon fiber for the GDL of the fuel cell, that is, a porous structure such as an expanded metal, a metal mesh, etc.

[0006] Fig. Figure 1 shows metallic porous bodies that can be used as GDL for a fuel cell, where (a) shows an example of a porous body in the form of an expanded metal and (b) shows an example of a porous body in the form of a metal mesh. Fig. The expanded metal 1 shown in Fig. 1(a) is an example of a porous plate having a plurality of rectangular openings formed by pressing or rolling a metal plate, and the ... Fig. The metal mesh 2 shown in Fig. 1(b) is an example of a porous plate formed by weaving a plurality of wires 2a in the form of a mesh.

[0007] These metallic porous bodies, which feature regular porous structures, can demonstrate consistent performance during use in fuel cells and reduce cell-to-cell variation. In addition, the diffusion of gaseous reactants is improved and water removal is efficient, which in turn contributes to an improvement in the overall performance of the fuel cells.

[0008] However, even in a case where these metallic porous bodies 1 and 2 are used as GDL, each metallic porous body 1 and 2 is stacked together with the components of a fuel cell such as the MEA, the separator, the gasket, etc., in the same manner as conventional methods to complete a fuel cell stack.

[0009] Conventionally, the metallic porous bodies 1 and 2 used in Fig. 1, cut to a size suitable for a reactive region on the separator of the fuel cell (i.e., a reactive region of the membrane electrode assembly), simply placed on the separator, and then assembled with the separator. Here, each of the metallic porous bodies 1 and 2 is a separate component that is not integrated with other components of the fuel cell.

[0010] These metallic porous bodies have sharp outer edges formed due to the material properties during cutting, and when the conventional metallic porous bodies are used without any modifications, the handling and operating properties are deteriorated due to the sharp outer edges formed during cell assembly.

[0011] In particular, the sharp outer edges of the metallic porous bodies are quite likely to damage the pin openings in the membrane electrode assembly that come into contact with the sharp outer edges during cell assembly, thus degrading the overall performance of the fuel cell stack.

[0012] Furthermore, since the conventional metallic porous bodies are separate components that are not integrated with any other component of the fuel cell, the arrangement of the metallic porous bodies becomes irregular during cell assembly, and therefore, the metallic porous bodies cannot be stacked accurately and precisely. Furthermore, an automatic assembly (stacking) method such as air suction cannot be used, which reduces the productivity of the fuel cell stack. With an automatic assembly (stacking) method such as air suction, the metallic porous bodies must be transported in a state where they are adsorbed to the suction device. Due to the presence of many pores on the surface (i.e.,However, due to the lack of a flat surface of the metallic porous bodies, it is difficult to achieve stable adsorption between the metallic porous bodies and the suction device. Therefore, to achieve stable adsorption, it is essential that the suction device adsorbs onto a non-porous flat surface.

[0013] The information disclosed in this Background section is intended only to provide a better understanding of the background of the invention and may therefore contain information that does not constitute prior art as already known to a person of ordinary skill in the art in this country.

[0014] EP 1 296 394 A1 describes a structure configured such that a separator made of a carbon plate or the like, a gas diffusion layer made of a carbon fiber or the like, and a gasket made of a liquid-cured rubber material or the like are integrally formed, and further gaskets are provided respectively on both surfaces of a pair of gas diffusion layers, holding an independent electrolyte membrane from both sides between the pair.

[0015] JP 2005 293 944 A discloses a fuel cell comprising a metal separator and diffusion layers, and further including a porous metal member provided between the metal separator and the diffusion layers, wherein the porous metal member is integrated with the metal separator.

[0016] GB 2 400 723 A relates to a medium temperature solid oxide fuel cell comprising a ferritic stainless steel substrate with a coarsely porous support and a non-porous frame housing for the coarsely porous support, a first electrode layer located in the non-porous frame and supported internally by the coarsely porous support of the substrate, an electrolyte layer disposed over the first electrode layer, and a second electrode layer disposed over the electrolyte layer. Summary of Revelation

[0017] The present invention provides a metallic porous body for a fuel cell that has improved handling and operational properties. Furthermore, the present invention provides a metallic porous body for a fuel cell that can be accurately and precisely stacked and processed using an automated assembly method, thereby improving the productivity of a fuel cell stack.

[0018] In one aspect, the present invention provides a metallic porous body for a fuel cell formed by stacking a plurality of unit cells made of a metallic porous body. This metallic porous body has a porous portion that contacts a reactive region of a membrane electrode assembly and corresponds to a reactive region of each of the unit cells; and a flat portion that has a flat surface structure formed along outer edges of the metallic porous body other than the porous portion constituting the reactive region. The metallic porous body is a gas diffusion layer.

[0019] According to the present invention, the planar portion is integrated with a gasket formed by injection molding such that the gasket is integrally bonded to the metallic porous body.

[0020] In another embodiment, the planar portion disposed on both sides of the metallic porous body has manifold apertures through which hydrogen, air, and coolant flow. These manifold apertures are the same size as the manifold apertures of a separator and are formed at positions corresponding to the manifold apertures of the separator. Specifically, the manifold apertures of the planar portion, together with the manifold apertures of the separator, form inlet and outlet manifolds for hydrogen, air, and coolant after assembly of the fuel cell.

[0021] In yet another embodiment, the distribution pipe openings of the planar portion may be integrated with a seal formed by injection molding, so that the metallic porous body around the distribution pipe openings of the planar portion may be integrally connected to the seal.

[0022] In yet another embodiment, the seal may be cast and bonded to both sides of the planar portion of the metallic porous body or cast to surround the outer edges and both sides of the planar portion.

[0023] In still another embodiment, the gasket may be molded to surround the planar portion and the outer edges of the separator in a state where the metallic porous body and the separator are stacked on each other, so that the separator may be further integrated with the metallic porous body through the gasket.

[0024] In a further embodiment, the gasket may be molded onto and bonded to the manifold openings of the separator to provide a state in which the metallic porous body and the separator are integrated with each other.

[0025] According to the present invention, through holes are provided in the planar portion formed at positions where the gasket is molded, so that the metallic porous body is firmly integrated with the gasket molded onto both sides of the planar portion by means of a resin to act as a gasket inserted into the through holes.

[0026] In some embodiments of the present invention, the separator also has through-holes formed at positions corresponding to the through-holes in the planar portion. In this embodiment, the gasket may be molded to surround the outer edges of the planar portion and the separator (including their corresponding through-holes). In such an embodiment, the metallic porous body and the separator may be stacked on top of each other, so that the metallic porous body may be firmly integrated with the gasket and the separator via the through-holes.

[0027] In yet another embodiment, the porous portion corresponding to the reactive region may be an expanded metal or a metal mesh. If the porous portion corresponding to the reactive region is an expanded metal, preferably only the porous portion has openings. In addition, in this embodiment of the present invention, a metal plate having no openings is arranged at the outer edges of the porous portion to form a flat portion integrated with the porous portion.

[0028] However, when the porous portion corresponding to the reactive region is a metal mesh, the outer edges of the metal mesh may be coated with a thin metal layer or inserted into the inner notches of an opening of a metal member having a rectangular frame structure, so that the thin metal layer or the metal member forms the flat portion and the metal mesh forms the porous portion.

[0029] Further aspects and embodiments of the invention are discussed below. Short description of the characters

[0030] The above and other features of the present invention will now be described in detail with reference to specific exemplary embodiments thereof, which are illustrated in the accompanying figures, which are provided herein for illustrative purposes only and are not intended to limit the present invention in any way. Fig. 1 shows conventional metallic porous bodies that can be used as components for a fuel cell, wherein (a) shows an example of a porous body in the form of an expanded metal and (b) shows an example of a porous body in the form of a metal mesh; Fig. 2 shows plan views of metallic porous bodies each having a planar portion according to an exemplary embodiment of the present invention; Fig. 3 shows plan views of metallic porous bodies integrated with a gasket according to an exemplary embodiment of the present invention; Fig. 4 shows plan views of metallic porous bodies integrated with a gasket according to another exemplary embodiment of the present invention; Fig. 5 and Fig. 6 show plan views of metallic porous bodies integrated with a seal in an improved manner according to an exemplary embodiment of the present invention; Fig. 7 shows plan views of metallic porous bodies integrated with a gasket and utilizing through-holes according to yet another exemplary embodiment of the present invention; and Fig. 8 to 11 are diagrams illustrating states in which a metallic porous body integrated with a gasket, a separator, and a membrane-electrode assembly according to an exemplary embodiment of the present invention are stacked.

[0031] The reference numerals indicated in the figures refer to the following components, as further discussed below: 10 metallic porous body 11 porous section (reactive area) 12 flat section 14 passage opening 20 Seal 30 Separator 31 passage opening 40 membrane electrode assembly

[0032] It should be understood that the accompanying figures are not necessarily to scale and present a somewhat simplified representation of various exemplary features illustrating the basic principles of the invention. The specific features of the embodiment of the present invention disclosed herein, including, for example, particular dimensions, orientations, positions, and shapes, will be determined in part by the conditions and circumstances of the particular application and use contemplated.

[0033] In the various figures of the drawing, the reference numerals designate the same or equivalent parts of the present invention. Detailed description

[0034] Reference will now be made in detail to various embodiments of the present invention, which are illustrated by way of example in the accompanying figures and described below. While the invention will be described in connection with exemplary embodiments, it should be understood that the present description is in no way intended to limit the invention to these exemplary embodiments. Rather, the invention is intended to cover not only the exemplary embodiments given, but also various alternatives, modifications, equivalents, and other embodiments that may be included within the spirit and scope of the invention as defined by the appended claims.

[0035] It should be understood that the term "vehicle" or "vehicular" or a similar term, as used herein, includes motor vehicles generally, such as passenger cars, including sports utility vehicles (SUVs), buses, trucks, various commercial vehicles, watercraft, including various boats and ships, aircraft, and the like, as well as hybrid vehicles, electric vehicles, plug-in electric hybrid vehicles, hydrogen-powered vehicles, and vehicles powered by other alternative fuels (e.g., fuels derived from sources other than petroleum). As used herein, a hybrid vehicle refers to a vehicle that has two or more sources of power, for example, vehicles capable of running on both gasoline and electricity.

[0036] The present invention provides a metallic porous body for a fuel cell used as a gas diffusion layer (GDL) component in the fuel cell. Specifically, the metallic porous body of the present invention includes a planar portion having a flat surface structure formed along the outer edges of the metallic porous body.

[0037] Fig. 2 shows plan views of metallic porous bodies each having a flat portion according to the present invention, wherein (a) shows a metallic porous body using an expanded metal, and (b) shows a metallic porous body using a metal net. Fig. Figure 2 also shows cross-sectional views taken along lines AA and BB, respectively.

[0038] As in Fig. 2, each of the metallic porous bodies 10 according to the present invention includes a porous portion 11 formed in a region corresponding to a reactive region on a separator of the fuel cell (ie, a reactive region connected to a catalyst layer of a membrane electrode assembly), and a flat portion 12 having a flat surface structure formed along outer edges of the metallic porous body other than the porous portion 11.

[0039] When an expanded metal is manufactured by forming a plurality of openings in the starting material, as Fig. 2(a), the flat portion 12 can be manufactured here without forming an opening in the outer edges. For example, a plurality of rectangular openings are formed by pressing or rolling a metal plate to form a porous structure in an area that does not correspond to the predetermined outer edges constituting the flat portion 12.

[0040] This means that the metal plate is designed such that the outer edges have no openings and correspond to the flat section 12 and that the interior has openings and corresponds to the porous section 11, which in turn corresponds to the reactive region of the porous body.

[0041] Alternatively, a porous plate or porous body in the form of a metal mesh may be formed by interweaving a plurality of wires. In this embodiment, a member forming the flat portion 12 may be provided separately, taking into account that the flat portion cannot be formed integrally with the outer edges, as is the case with the plate of the porous body in the form of an expanded metal.

[0042] That is, a metal element 12 having a rectangular frame structure can be provided into which a metal net 11 can be inserted, as shown in Fig. 2(b). The outer edges of the metal mesh 11 (ie, the porous portion) can be mechanically inserted into inner notches of a rectangular opening of the metal element 12 (ie, the flat portion), as shown in the cross-sectional view BB of Fig. 2, so that the metal net 11 is arranged in the rectangular opening of the metal member 12 so as to integrally form a porous body 10 in the form of a metal net having a flat portion 12 formed at the outer edges.

[0043] In this case, the metal element 12 corresponds to the flat section and the metal mesh 11 corresponds to the porous section 11.

[0044] Alternatively, the flat portion 12 may also be formed by applying a thin metal layer along the outer edges of the metal mesh 11.

[0045] In one embodiment, the size of the metallic porous body 10 can substantially correspond to the overall size of the separator with which it—as well as the membrane-electrode assembly—is to be assembled during cell assembly. In addition, distribution tube openings 13, through which hydrogen, air, and coolant flow, can be formed in the planar portion 12 at both ends of the metallic porous body 10.

[0046] The manifold openings 13 can be the same size as corresponding manifold openings of the separator through which hydrogen, air, and coolant flow, and they are formed at positions corresponding to the positions of the separator, respectively. Therefore, after assembly of the fuel cell, the manifold openings 13 at both ends of the metallic porous body 10 and the manifold openings of the separator form an inlet manifold and an outlet manifold of the fuel cell stack, through which hydrogen, air, and coolant are supplied to or discharged from the fuel cell stack according to the respective unit cell (i.e., through each flow field of the separator).

[0047] Since the metallic porous body 10 formed as described above has a flat portion 12 along the outer edges, a gasket can be formed integrally on the flat portion 12, so that a metallic porous body integrated with a gasket can be formed.

[0048] Fig. 3 shows plan views of metallic porous bodies integrated with a gasket according to an exemplary embodiment of the present invention, wherein (a) shows a metallic porous body 10 integrated with a gasket and using an expanded metal, and (b) shows a metallic porous body 10 integrated with a gasket and using a metal mesh.

[0049] The metallic porous body 10 integrated with a gasket can be formed by pressing the metallic porous body 10 (in which the flat portion and the porous portion are integrally formed with each other) provided in Fig. 2, is mounted in an injection mold, and a resin to function as a gasket 20 is injection-molded onto the surface of the flat portion 12. When the gasket 20 is integrally formed on the flat portion 12 of the metallic porous body 10 by injection molding, the gasket 20 may be bonded as such to both sides of the flat portion 12 of the metallic porous body 10.

[0050] Out of Fig. 3 it can be seen that the seal 20 is integrally connected to the metallic porous body 10 by injection molding along the entire circumference of the porous section 11 and the corresponding distribution pipe openings 13.

[0051] According to the present invention, therefore, when using a flat portion 12 formed along the outer edges of the metallic body 10, as shown in Fig. 3, it is possible to form a metallic porous body 10 integrated with a gasket by injection-molding the gasket 20 onto the planar portion 12.

[0052] As a result, when the metallic porous body 10 according to the present invention integrated with a gasket is used, an increase in productivity can be observed when the fuel cell stack is assembled by stacking a plurality of unit cells.

[0053] While conventional metallic porous bodies have sharp outer edges, the metallic porous body 10 according to the present invention further includes a flat portion 12 formed along the outer edges, thereby improving handling and operational properties during cell assembly. Furthermore, it is possible to minimize the risk of damage to the membrane-electrode assembly, thereby improving cell performance uniformity and overall safety.

[0054] Fig. 4 shows plan views of metallic porous bodies integrated with a gasket according to another exemplary embodiment of the present invention, wherein (a) shows a metallic porous body 10 integrated with a gasket and using an expanded metal, and (b) shows a metallic porous body 10 integrated with a gasket and using a metal mesh.

[0055] In the embodiment of the Fig. 4 is the total circumference of a flat section (in Fig. 2 with the reference numeral 12), which does not correspond to the porous section 11 and the distribution pipe openings 13, is integrally surrounded by a seal 20.

[0056] As shown in the figure, the gasket 20 may, for example, be injection-molded to surround the flat portion on both sides of the metallic porous body 10. More specifically, the metallic porous body integrated with a gasket, in which the flat portion around the porous portion 11 and the distribution pipe openings 13 is integrated with the gasket 20, may be formed, for example, by injecting a resin to function as the gasket 20 onto the flat portion around the porous portion 11 and the distribution pipe openings 13.

[0057] When a metallic porous body 10 integrated with a gasket and in which the gasket 20 is bonded to the planar portion is used, a stack assembling apparatus using an automatic stacking method such as air suction can be advantageously used, thereby improving the efficiency of the assembling process.

[0058] Alternatively, the Fig. 5 and Fig. 6 Top views of metallic porous bodies providing improved integration with a seal according to an illustrative embodiment of the present invention. Fig. 5 shows a state of the metallic porous body before bonding with a gasket, and Fig. 6 shows a state of the metallic porous body after bonding with a gasket. Fig. 5 and Fig. 6 shows (a) an example in which an expanded metal is used as the metallic porous body, and (b) shows an example in which a metallic net is used as the metallic porous body.

[0059] As in the Fig. 5 and Fig. As shown in Fig. 6, through holes 14 are formed at positions of the flat portion 12 of the metallic porous body 10 where the gasket 20 may be formed, for example, by injection molding. A resin for the gasket 20 may be injection-molded onto the flat portion 12, for example, such that the through holes 14 are filled with the resin. Since the resin is injected into the through holes 14, the gasket 20 is firmly bonded to the flat portion 12 of the metallic porous body 10.

[0060] Since the seal 20 can be injection-molded, for example, along the through-holes 14 of the planar portion 12 on both sides of the metallic porous body 10, the seals 20 on both sides of the metallic porous body 10 are integrally connected to one another, in particular through the through-holes 14, and are therefore firmly connected to the planar portion 12 of the metallic porous body 10 in the form of a single casting.

[0061] The plurality of through holes 14 are formed at regular intervals at positions where the seal 20 is connected to the planar portion 12, ie, around the porous portion 11 and the distribution pipe openings 13. Although in the embodiments of the Fig. 5 and Fig. 6 circular through-holes 14 are shown, the through-holes may have various shapes, such as a triangle, a rectangle, etc., and the number, size, and pitch of the through-holes may vary depending on the size of the metallic porous body. Therefore, the number, size, and pitch of the through-holes are not particularly limited in the present invention.

[0062] Furthermore, the shape and size of the gasket 20 may be appropriately selected in consideration of the size of the metallic porous body 10, and any structure capable of maintaining airtightness of the porous portion 11 and the distribution pipe openings 13 may be used in the present invention.

[0063] Fig. Fig. 7 shows plan views of metallic porous bodies integrated with a gasket and using through-holes according to yet another exemplary embodiment of the present invention, wherein the through-holes 14 are formed in the same manner as in Fig. 6 and the seal 20 is integrally formed so as to cover the flat portion (which is shown in Fig. 6 is designated by the reference numeral 12) of each metallic porous body 10.

[0064] For example, as shown in the figure, the gasket 20 may be injection-molded to surround the flat portion on both sides of the metallic porous body 10 in such a manner that a resin for the gasket 20 may be injection-molded to the flat portion around the porous portion 11 and around the distribution pipe openings 13 so that the flat portions around the porous portion 11 and around the distribution pipe openings 13 are integrated by the gasket 20, thereby forming a metallic porous body integrated with a gasket.

[0065] The Fig. 8 to 11 are diagrams illustrating states in which a metallic porous body 10 integrated with a gasket, a separator 30, and a membrane-electrode assembly 40 according to the present invention are stacked. The metallic porous body 10 of the present invention may be integrated with a gasket 20 (see Fig. 8(a), Fig. 9(a), Fig. 10(a) and Fig. 11(a)) or it can be integrated with a seal 20 and a separator 30 (see Fig. 8(b), Fig. 9(b), Fig. 10(b) and Fig. 11(b)).

[0066] In this way, the present invention can provide a metallic porous body 10 further integrating the separator 30. This corresponds to a metallic porous body integrated with a gasket and a separator (or an assembly of a gasket, a separator, and a metallic porous body), as well as a metallic porous body 10 integrated with a gasket, which are repeatedly stacked with the membrane-electrode assembly 40 to form a fuel cell stack.

[0067] The Fig. 8 and Fig. 9 are cross-sectional views showing plate metal separators, and the Fig. 10 and Fig. 11 are cross-sectional views showing flow field plate metal separators arranged along the same lines AA and BB of the Fig. 2 were taken.

[0068] In each figure, (a) shows an example of a metallic porous body 10 integrated with a gasket 20 (ie, the metallic porous body integrated with a gasket), and (b) shows an example of a metallic porous body 10 integrated with a gasket 20 and a separator 30 (ie, the metallic porous body integrated with a gasket and a separator).

[0069] More precisely, Fig. 8(a) shows an example of a metallic porous body 10 integrated with a seal and manufactured by forming through holes 14 in the planar portion 12 of the metallic porous body 10 as shown in Fig. 5, and the seal 20 was injection-molded, for example, so that the seal 20 and the metallic porous body 10 are inserted through the through-hole 14, as shown in Fig. 6 is shown, are firmly integrated with each other.

[0070] Here, the metallic porous body 10 integrated with the seal 20 may be a porous body in the form of an expanded metal or a porous body in the form of a metal mesh, as discussed above. Although the Fig. 6 shown metallic porous body 10, which is integrated with a seal and in which the seal 20 can be injection-molded, for example, along the through-openings 14, is used, the one shown in Fig. 7, which is integrated with a seal and in which the seal 20 can be injection-molded, for example, so that it surrounds the flat section, including the through openings 14, can be used.

[0071] Besides, a porous body 10 integrated with a gasket may be stacked on both sides of the membrane electrode assembly 40, and the separator 30 may be stacked on the outside of the metallic porous body 10 integrated with a gasket, as shown in Fig. 8(a).

[0072] That is, the separator 30, the metallic porous body 10 integrated with a gasket, the membrane-electrode assembly 40, the metallic porous body 10 integrated with a gasket, and the separator 30 are repeatedly stacked in this order. Here, the gasket 20, which is integrally bonded to the metallic porous body 10, maintains the airtightness between the separator 30 and a polymer electrolyte membrane 41 of the membrane-electrode assembly 40.

[0073] Alternatively, Fig. 9(a) an example of a metallic porous body integrated with a gasket and manufactured without forming a through hole, ie the metallic porous body integrated with a gasket, from Fig. 3.

[0074] As in Fig. 3, the metallic porous body 10 integrated with a seal was manufactured here by applying the seal 20 along the entire circumference of the porous section 11 and the distribution pipe openings (in Fig. 9 not shown and in Fig. 3 with the reference numeral 13) e.g. injection molded. As a further alternative, instead of the metallic porous body 10 which is integrated with a seal, as shown in Fig. 3, a metallic porous body 10 which is integrated with a seal and was manufactured by the seal (in Fig. 7 with the reference numeral 20) has been injection-molded so as to surround the flat portion 12 (ie a structure without the through holes in the embodiment of the Fig. 7).

[0075] Even in this case, during the assembly of the fuel cell stack, the separator 30, the metallic porous body 10 integrated with a gasket, the membrane-electrode assembly 40, the metallic porous body 10 integrated with a gasket, and the separator 30 are assembled in the same manner as in Fig. 8(a) repeatedly stacked on top of each other.

[0076] In contrast, Fig. 8(b) shows an example of a metallic porous body integrated with a gasket and a separator, which is manufactured by forming through holes 31 coinciding with the through holes 14 of the metallic porous body 10 along the outer edges of the separator 30 and injection-molding the gasket 20 along the through holes 31 of the separator and the metallic porous body 10, for example, which are stacked on top of each other, so that the metallic porous body 10 and the separator 30 are integrally connected to each other via the gasket 20.

[0077] When the metallic porous body 10 and the separator 30 are stacked on top of each other, the gasket 20 is injection-molded, as shown in the figure, onto the flat portion 12 of the metallic porous body 10 and onto the outer edges of the separator 30, including the through-holes 14 and 31, so that the gaskets 20, which are injection-molded on both sides, are connected to each other through the through-holes 14 and 31, respectively. As a result, the separator 30 is further integrated with the metallic porous body 10 through the gaskets 20.

[0078] In this case, during assembly of the fuel cell stack, a metallic porous body integrated with a gasket and a separator is stacked on both sides of the membrane electrode assembly 40. After assembly of the fuel cell stack, the metallic porous body 10 is arranged on both sides of the membrane electrode assembly 40, and the separator 30 is arranged on the outside of the metallic porous body 10.

[0079] That is, the separator 30, the metallic porous body 10, the membrane-electrode assembly 40, the metallic porous body 10, and the separator 30 are repeatedly stacked in this order.

[0080] Although in Fig. 8(b) shows a metallic porous body which is integrated with a seal and a separator and in which the seal 20 can be injection-molded, for example, along the through-holes 14 and 31, the metallic porous body can be made of Fig. 7, which is integrated with a seal and with a separator and which is manufactured by, for example, injection-molding the seal so that it surrounds the flat portion of the metallic porous body and the outer edges of the separator, including the through-holes, can be used (ie a structure in which the through-holes in the embodiment of Fig. 9B were added).

[0081] Next, Fig. 9(b) shows an example of a metallic porous body integrated with a seal and a separator, the integration being carried out without forming a through-hole.

[0082] The metallic porous body integrated with a gasket and a separator was manufactured by, for example, injection molding the gasket 20 to surround the flat portion 12 of the metallic porous body 10 and the outer edges of the separator 30, so that the separator 30 and the metallic porous body 10 are integrated with each other through the gasket 20.

[0083] During the assembly of the fuel cell stack, the metallic porous body, which is integrated with a seal and a separator, is in this case as well as in Fig. 9(a) stacked on both sides of the membrane-electrode assembly 40. After assembly of the fuel cell stack, the metallic porous body 10 is arranged on both sides of the membrane-electrode assembly 40, and the separator 30 is arranged on the outside of the metallic porous body 10.

[0084] That is, the separator 30, the metallic porous body 10, the membrane-electrode assembly 40, the metallic porous body 10, and the separator 30 are repeatedly stacked in this order.

[0085] If the separators are integrated with the metallic porous bodies, as in the Fig. 8(b) and Fig. 9(b), the seal may be integrally injection molded around the distribution pipe openings of the corresponding separator.

[0086] In addition, as in the examples of Fig. 10 and Fig. 11, no differences between the integrally connected structure and the stacked structure and the structures from the examples of Fig. 8 and Fig. 9, except that flow field metal plate separators are used instead of metal plate separators.

[0087] This means that in the Fig. 10(a) and Fig. 11(a) no differences between the integrally connected structure of the gasket 20 and the metallic porous body 10 and the stacked structure of the metallic porous body integrated with a gasket, the membrane electrode assembly 40 and the separator and the structures of the Fig. 8(a) and Fig. 9(a). In addition, there are Fig. 10(b) and Fig. 11(b) no differences between the integrally connected structure of the gasket 20, the separator 30 and the metallic porous body 10 and the stacked structure of the metallic porous body integrated with a gasket and a separator and the membrane electrode assembly 40 and the structures of the Fig. 8(b) and Fig. 9(b).

[0088] In particular, Fig. 10 a structure integrated with the through openings 14 and 31, and Fig.11 shows a structure that is integrated without forming a through hole.

[0089] The metallic porous body provided by the present invention for fuel cells advantageously utilizes a flat portion having a flat surface structure formed along the outer edges of a metallic porous body, thereby improving handling and operational properties. Furthermore, the metallic porous body described above eliminates sharp outer edges and, therefore, when used as a gas diffusion layer, prevents damage to the pin openings in the membrane electrode assembly, thereby preventing deterioration of the overall performance of the fuel cell.

[0090] Furthermore, the metallic porous body according to the present invention can be accurately and precisely stacked and processed by an automatic assembly method, thereby improving the productivity of the fuel cell stack.

[0091] The invention has been described in detail with reference to exemplary embodiments thereof. However, one skilled in the art will understand that changes may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

[1] A metallic porous body (10) for a fuel cell formed by stacking a plurality of unit cells consisting of a metallic porous body (10), the metallic porous body (10) comprising: a porous portion (11) in contact with a reactive region of a membrane electrode assembly (40) and corresponding to a reactive region of each unit cell; a flat portion (12) having a flat surface structure formed along the outer edges of the metallic porous body (10) which does not correspond to the porous portion (11) constituting the reactive region, wherein the metallic porous body (10) is a gas diffusion layer, and wherein the planar portion (12) is integrated with a gasket (20) such that the gasket (20) is integrally connected to the metallic porous body (10), and the planar portion (12) has through holes (14) formed at positions where the gasket (20) is molded, so that the metallic porous body (10) is firmly integrated with the gasket (20) molded on both sides of the planar portion (12) by a resin to function as a gasket (20) introduced into the through holes (14). [2] The metallic porous body (10) according to claim 1, wherein the planar portion (12) disposed on both sides of the metallic porous body (10) has manifold openings through which hydrogen, air, and coolant flow, which have the same size as the manifold openings of a separator (30) and are formed at positions corresponding to the manifold openings of the separator (30), wherein the manifold openings of the planar portion (12) together with the manifold openings of the separator (30) form inlet and outlet manifolds for hydrogen, air, and coolant after assembly of the fuel cell. [3] A metallic porous body (10) according to claim 2, wherein the distribution pipe openings of the planar portion (12) are integrated with a gasket (20) formed by injection molding, so that the metallic porous body (10) is integrally connected to the gasket (20) around the distribution pipe openings of the planar portion (12). [4] A metallic porous body (10) according to claim 1, wherein the gasket (20) is molded and bonded to both sides of the planar portion (12) of the metallic porous body (10) or is molded to surround the outer edges and both sides of the planar portion (12). [5] The metallic porous body (10) according to claim 1, wherein the gasket (20) is molded to surround the planar portion (12) and the outer edges of the separator (30) in a state where the metallic porous body (10) and the separator (30) are stacked on each other, so that the separator (30) is further integrated with the metallic porous body (10) through the gasket (20). [6] The metallic porous body (10) according to claim 5, wherein the gasket (20) is molded and bonded to the manifold openings of the separator (30) in a state in which the metallic porous body (10) and the separator (30) are integrated with each other. [7] The metallic porous body (10) according to claim 1, wherein the planar portion (12) has through holes (14) formed at positions where the gasket (20) was molded, the separator (30) has through holes (14) formed at positions corresponding to the through holes (14) of the planar portion (12), and the gasket (20) is molded in a state where the metallic porous body (10) and the separator (30) are stacked on each other so as to surround the outer edges including the through holes (14) of the planar portion (12) and the separator (30), so that the metallic porous body (10) is firmly integrated with the gasket (20) and the separator (30) through the through holes (14). [8] A metallic porous body (10) according to claim 1, wherein the porous portion (11) corresponding to the reactive region is an expanded metal, and wherein the porous portion (11) has openings, and a metal plate arranged at the outer edges of the porous portion has no openings and forms the planar portion (12) integrated with the porous portion (11). [9] A metallic porous body (10) according to claim 1, wherein the porous portion (11) corresponding to the reactive region is a metal mesh, and wherein the outer edges of the metal mesh are coated with a thin metal layer such that the thin metal layer is the flat portion and the metal mesh is the porous portion (11). [10] A metallic porous body (10) according to claim 1, wherein the porous portion (11) corresponding to the reactive region is a metal mesh, and wherein the outer edges of the metal mesh are fitted into the inner notches of an opening of a metal member having a rectangular frame structure so that the metal member is the flat portion and the metal mesh is the porous portion (11).

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