MODULARIZED UNIT CELL FOR FUEL CELL STACKS

Abstract

In one embodiment, a modularized unit cell for a fuel cell stack comprises an insert comprising a membrane electrode assembly in which a first electrode layer is formed on a first surface and a second electrode layer is formed on a second surface, and a pair of gas diffusion layers are arranged on both surfaces.The cell may further include a plate frame formed by joining a plurality of plates, configured to surround an edge of the insert, joined at an edge of the insert and an interface thereof, and having a discharge flow field formed therein along a longitudinal direction near an edge in a width direction for discharging generated water generated from the insert, and a pair of partition plates having flow fields formed on both surfaces of the plate frame and configured to supply a reaction gas and discharge the water generated by a reaction.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a modularized unit cell for a fuel cell stack. BACKGROUND

[0002] A fuel cell is a kind of power generation device that converts chemical energy contained in a fuel into electrical energy through an electrochemical reaction in a stack, and the fuel cell can not only provide driving power for industry, household and a vehicle, but also power a small electronic product such as a portable device, and recently its application range has been gradually expanded as a high-efficiency clean energy source.

[0003] A unit cell of a general fuel cell has a membrane electrode assembly (MEA) arranged on its innermost side, and the membrane electrode assembly consists of a polymer electrolyte membrane capable of moving protons and catalyst layers deposited on both surfaces of the electrolyte membrane so that hydrogen and oxygen can react, that is, an anode and a cathode.

[0004] Further, a gas diffusion layer (GDL) is laminated on an outer part of the membrane electrode assembly, that is, an outer part where the anode and the cathode are arranged, and a partition plate on which a flow field is formed is arranged on the outer side of the gas diffusion layer to supply a fuel and discharge water generated by the reaction.

[0005] A plurality of unit cells formed from the configurations described above form a fuel cell stack by being laminated in series so that the fuel cell can generate power at a desired level. The fuel cell stack includes an end plate connected to the outermost side of the unit cells to support and fix the plurality of unit cells.

[0006] Meanwhile, in the prior art, for the maintenance of the seal of the unit cells and to simplify a lamination process thereof, a membrane electrode gasket assembly (MEGA) in which the membrane electrode assembly and the gasket are modularized has been manufactured and used.

[0007] Furthermore, research has recently been conducted on a multifunctional frame in which the membrane electrode gas diffusion layer assembly (power generating assembly (EGA)), in which the gas diffusion layer is bonded to the membrane electrode assembly, and the gasket are modularized into one unit.

[0008] One of the results of such research is the fabrication of an elastomer frame that surrounds the edge of the membrane electrode seal assembly (MEGA).

[0009] However, the elastic body frame is manufactured by manufacturing a plate-shaped frame using a heat-sealable thermoplastic elastomer (TPE) and then bonding the frame to the membrane electrode gasket assembly (MEGA) by heat fusion, and in this case, there is a problem that the membrane electrode gasket assembly (MEGA) is damaged or the elastomer frame is deformed due to heat and pressure provided for bonding during heat fusion.

[0010] Furthermore, since the elastomer frame is bonded to the metal partition plate by heat fusion, a problem arises in which the bonding of the partition plate and the elastomer frame cannot be achieved with the desired strength. As a result, a problem arises in the alignment of the unit cells when manufacturing the fuel cell stack by unit cell lamination.

[0011] In the case of the fuel cell, a problem arises that the water produced by the chemical reaction collects in an outer region of the reaction zone and causes corrosion of the membrane electrode assembly (MEA).

[0012] Since corrosion of the membrane electrode assembly (MEA) severely affects the durability of the fuel cell, it should be prevented at all costs.

[0013] Generally, a water drainage groove structure is often formed to effectively drain the generated water from the fuel cell. However, when discharging the generated water by forming a water drainage groove on the membrane electrode assembly (MEA) or gas diffusion layer (GDL), or by collecting the generated water on the metal partition plate, there is a problem that the generated water still remains in the reaction region.

[0014] Furthermore, there are disadvantages that it may be very difficult to actually implement the fabrication of the groove structure on a thin layer, such as the membrane electrode assembly (MEA) or the gas diffusion layer (GDL), into the production process, and the reaction area may be changed in the case of fabricating the structure by molding on the metal partition plate.

[0015] The above description of the background technology is intended only for understanding the background of the present disclosure and is not intended to imply that the present disclosure falls within the scope of the already well-known prior art. SUMMARY

[0016] The present disclosure relates to a modularized unit cell for a fuel cell stack, and more particularly to a modularized unit cell for a fuel cell stack that can smoothly discharge generated water.

[0017] An embodiment of the present disclosure provides a modularized unit cell for a fuel cell stack that can connect and modularize a membrane electrode gasket assembly (MEGA) and a pair of separator plates by fabricating a plate frame having a three-dimensional (3D) shape by manufacturing a plurality of plates using a hard plastic material, punching out a specific shape from each of the plurality of plates, and connecting the respective plates.

[0018] In particular, an embodiment of the present disclosure provides a modularized unit cell for a fuel cell stack in which an output flow field for discharging generated water is formed within a plate frame.

[0019] The technical problems to be solved by an embodiment of the present disclosure are not necessarily limited to the above-mentioned technical problems, and it can be assumed that other technical problems not mentioned can be clearly understood by those skilled in the art to whom the present disclosure is directed from the description of the embodiments of the present disclosure.

[0020] A unit cell for a fuel cell stack according to an embodiment of the present disclosure includes a cartridge formed of a membrane-electrode assembly, a first electrode layer formed on one surface of a polymer electrolyte membrane, and a second electrode layer formed on the other surface of the polymer electrolyte membrane. One embodiment further includes a pair of gas diffusion layers disposed on both surfaces of the membrane-electrode assembly, a plate frame formed by joining a plurality of plates, arranged to surround an edge of the cartridge in an outer region of the cartridge, joined at the edge of the cartridge and at an interface thereof, and having a discharge flow field formed therein along a longitudinal direction at the edge in a width direction for discharging water generated from the cartridge.An embodiment further includes a pair of partition plates having flow fields formed on both surfaces of the plate frame and configured to supply a reaction gas and discharge water generated by a reaction.

[0021] In one embodiment, the plate frame comprises a first base plate and a second base plate, each having a central region on which a first insert through-hole is formed as a rim for receiving the insert, and a first flow field plate bonded between the first base plate and the second base plate and having a central region on which a second insert through-hole is formed, which communicates with the first insert through-hole, wherein the discharge flow field is formed on the first flow field plate.

[0022] In one embodiment, on the first base plate and the second base plate, a plurality of first manifold through-holes are formed on one side in a longitudinal direction based on the first insert through-hole and configured to flow in and out a reaction gas and a cooling water, and a plurality of second manifold through-holes are formed on the other side in the longitudinal direction and configured to flow in and out the reaction gas and the cooling water.In one embodiment, on the first flow field plate, a plurality of third manifold through-holes communicating with the plurality of first manifold through-holes are formed on one side in a longitudinal direction based on the second insert through-hole, and a plurality of fourth manifold through-holes communicating with the second manifold through-holes are formed on the other side in the longitudinal direction, and the discharge flow field is a first discharge flow field communicating with any one of the plurality of third manifold through-holes from a position adjacent to the second insert through-hole on the first flow field plate.

[0023] In one embodiment, the pair of gas diffusion layers is divided into a first gas diffusion layer facing a first electrode layer of the membrane-electrode assembly and a second gas diffusion layer facing a second electrode layer of the membrane-electrode assembly. In one embodiment, the pair of partition plates is divided into a first partition plate facing the first gas diffusion layer and a second partition plate facing the second gas diffusion layer, and the first discharge flow field communicates with any one of the plurality of first manifold through-holes in a region where the first gas diffusion layer and the first partition plate come into contact with each other.

[0024] In one embodiment, the first discharge flow field is divided into a first main discharge flow field formed along a longitudinal direction at an edge in a width direction of the plate frame and having an end part communicating with any one of the plurality of third manifold through-holes, and a plurality of first branched discharge flow fields spaced at a certain interval from the first main discharge flow field along a longitudinal direction and branched toward the second insert through-hole.

[0025] In one embodiment, the first main discharge flow field communicates with the third manifold through-hole located at a lowermost end among the plurality of third manifold through-holes based on a direction of gravity.

[0026] In one embodiment, the second insert through-hole is formed such that an edge thereof is larger than the first insert through-hole by a certain width. In one embodiment, due to a size difference between the second insert through-hole and the first insert through-hole, a step portion equal to a thickness of the first flow field plate is formed when the first base plate, the second base plate, and the first flow field plate are joined together. In one embodiment, an edge of the insert is bonded to the step portion.

[0027] In the modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure, the plate frame is composed of a first base plate and a second base plate, each having a central portion on which a first insert through-hole arranged as an edge of the insert is seated, and a first flow field plate and a second flow field plate, each having a central portion on which a second insert through-hole communicating with the first insert through-hole is formed, wherein the first flow field plate is bonded between the first base plate and the second base plate, the second flow field plate is bonded to an outer surface of the second base plate, and the discharge flow field is divided into a first discharge flow field formed on the first flow field plate and a second discharge flow field formed on the second flow field plate.is divided into

[0028] In one embodiment, on each of the first base plate and the second base plate, a plurality of first manifold through-holes are formed on one side in a longitudinal direction based on the first insert through-hole and configured to flow in and out a reaction gas and a cooling water, and a plurality of second manifold through-holes are formed on the other side in the longitudinal direction and configured to flow in and out the reaction gas and the cooling water.In one embodiment, on each of the first flow field plate and the second flow field plate, a plurality of third manifold through-holes communicating with the plurality of first manifold through-holes are formed on one side in a longitudinal direction based on the second insert through-hole, and a plurality of fourth manifold through-holes communicating with the second manifold through-holes are formed on the other side in the longitudinal direction.In one embodiment, the output flow field is a first output flow field communicating with any one of the plurality of third manifold through-holes from a position adjacent to the second insert through-hole on the first flow field plate, and a second output flow field communicating with any one of the plurality of fourth manifold through-holes from a position adjacent to the second insert through-hole on the second flow field plate.

[0029] In one embodiment, the pair of gas diffusion layers is divided into a first gas diffusion layer facing a first electrode layer of the membrane-electrode assembly and a second gas diffusion layer facing a second electrode layer of the membrane-electrode assembly. In one embodiment, the pair of separation plates is divided into a first separation plate facing the first gas diffusion layer and a second separation plate facing the second gas diffusion layer.In one embodiment, the first discharge flow field communicates with any one of the plurality of third manifold through-holes in a region where the first gas diffusion layer and the first partition plate come into contact with each other, and the second discharge flow field communicates with any one of the plurality of fourth manifold through-holes in a region where the second gas diffusion layer and the second partition plate come into contact with each other.

[0030] In one embodiment, the first discharge flow field is divided into a first main discharge flow field formed along a longitudinal direction at an edge in a width direction of the plate frame and having an end part communicating with any one of the plurality of third manifold through-holes, and a plurality of first branched discharge flow fields spaced at a certain distance from the first main discharge flow field along a longitudinal direction and branched toward the second insert through-hole.

[0031] In one embodiment, the second discharge flow field is divided into a second main discharge flow field formed along a longitudinal direction at an edge in a width direction of the plate frame and having an end part communicating with any one of the plurality of fourth manifold through-holes, and a plurality of second branched discharge flow fields spaced at a certain distance from the second main discharge flow field along a longitudinal direction and branched toward the second insert through-hole.

[0032] In one embodiment, the first main output flow field communicates with the third manifold through-hole located at a lowermost end based on a direction of gravity among the plurality of third manifold through-holes, and the second main output flow field communicates with the fourth manifold through-hole located at a lowermost end based on a direction of gravity among the plurality of fourth manifold through-holes.

[0033] In one embodiment, the first discharge flow field and the second discharge flow field are formed independently of each other at opposite positions based on the second base plate.

[0034] In one embodiment, a seal is provided on any one of the pair of partition plates surrounding a region where the insert is disposed, and the discharge flow field is formed between an outermost angle of the insert and a position where the seal is provided.

[0035] In one embodiment, the plate frame is formed from an engineering plastic or a high-performance plastic having a coefficient of thermal expansion equal to or less than 40.

[0036] In one embodiment, corrosion of the MEA and the partition plate can be prevented because the flow of water generated in the reaction region is directed to the interior of the plate frame, i.e., the area outside the reaction region.

[0037] In one embodiment, since the discharge flow field for guiding the generated water is directly connected to the manifold through-hole without being connected to the diffusion region, the reactant gas supply and distribution in the diffusion region can be accurately predicted, and thus a uniform distribution of the reactant gas in the reaction region can be expected.

[0038] In one embodiment, it is not necessary to separately form an additional structure for discharging the generated water on the metal partition plate because the structure for discharging the generated water is formed within the plate frame.

[0039] In one embodiment, the reaction surface can be maintained as much as possible since an additional structural change of the metal partition plate is not required.

[0040] In one embodiment, since the discharge flow field for discharging the generated water is formed on the plate frame, the 3D structure discharge flow field can be easily implemented in various shapes even by simply changing the shapes and punching patterns of the respective plates constituting the plate frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and other features and advantages of embodiments of the present disclosure can be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a diagram showing a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; Fig. 2 is a diagram unfolding and showing the structure of a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; Fig. 3 is a diagram unfolding and showing the structure of a plate frame constituting a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; Fig. 4A and Fig. 4B are diagrams showing main part cross sections of a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; Fig. 5 is a diagram showing a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; Fig. 6 is a diagram unfolding and showing the structure of a plate frame constituting a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure; and Fig. 7A and Fig. 7B are diagrams showing main part cross sections of a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF EXAMPLE DESIGNS

[0042] Hereinafter, the embodiments disclosed in the specification will be described in detail with reference to the accompanying drawings, wherein like reference numerals may be used for like or similar components regardless of the reference numerals, and duplicate explanations thereof may be omitted.

[0043] The suffixes "module" and "part" for the components used in the following description are specified or may be used interchangeably to facilitate the preparation of the description and do not necessarily have distinguishable meanings or roles in themselves.

[0044] When explaining embodiments disclosed in the present specification, if it is determined that detailed explanation of related known technology may obscure the gist of the embodiments disclosed in the present specification, the detailed explanation may be omitted. Furthermore, the accompanying drawings may contribute to the understanding of embodiments of the present specification, and it can be understood that the technical ideas disclosed in the present specification are not necessarily limited by the accompanying drawings, but include all modifications, equivalents, and substitutes included within the ideas and technical scope of the present disclosure.

[0045] Terms including ordinal numbers, such as "first, second, and the like," may be used to describe various components, but the components are not necessarily limited by the terms. Such terms may only serve to distinguish one component from another.

[0046] When a particular component is described as "connected" or "coupled" to another component, this can be understood to mean that the particular component is directly connected or coupled to the other component and / or that another component may be present in the middle. Conversely, when a particular component is described as "directly connected" or "directly coupled" to another component, it can be understood that the other component is not present in the middle.

[0047] A singular expression may include a plural expression unless the context clearly defines otherwise.

[0048] In this specification, it should be understood that the term "comprising" or "having" specifies the presence of the stated features, numbers, steps, operations, components, parts, or a combination thereof, but does not exclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or a combination thereof.

[0049] First, an embodiment of a modularized unit cell for a fuel cell stack using a plate frame is described.

[0050] Fig. 1 is a diagram showing a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure. Fig. 2 is a diagram unfolding and showing the structure of a modularized cell for a fuel cell stack according to an embodiment of the present disclosure. Fig. 3 is a diagram unfolding and showing the structure of a plate frame constituting a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure.

[0051] As in the Fig. As shown in FIGS. 1 to 3, a modularized unit cell for a fuel cell stack may be provided with a membrane-electrode-gas diffusion layer assembly (electricity generation assembly (EGA)) (hereinafter referred to as a cartridge 10) in which a membrane-electrode assembly 11 having a first electrode layer formed on one surface of a polymer electrolyte membrane and a second electrode layer formed on the other surface thereof, and a pair of gas diffusion layers 12a and 12b disposed on both surfaces of the membrane-electrode assembly 11 are bonded together. The modularized unit cell may include a plate frame 100 formed by bonding a plurality of plates, positioned to surround an edge of the cartridge 10 in an outer region of the cartridge 10, and bonded at the edge of the cartridge 10 and an interface thereof.The modularized unit cell may include a pair of partition plates 20a and 20b with flow fields formed on both surfaces of the plate frame 100 and configured to supply a reaction gas and discharge the water generated by a reaction. The insert 10, the plate frame 100, and the pair of partition plates 20a and 20b may be bonded to each other by an adhesive member 200 at their respective interfaces.

[0052] In one embodiment, the insert 10 is an assembly obtained by laminating the membrane-electrode assembly 11 and the pair of gas diffusion layers 12a and 12b. Preferably, the gas diffusion layers 12a and 12b are arranged and laminated on one surface and the other surface of the membrane-electrode assembly 11. The membrane-electrode assembly 11 may consist of a polymer electrolyte membrane capable of moving protons and catalyst layers deposited on both surfaces of the electrolyte membrane so that hydrogen and oxygen can react, i.e., a first electrode layer and a second electrode layer. The first electrode layer may be a cathode, and the second electrode layer may be an anode.Of course, the first electrode layer and the second electrode layer are not necessarily limited thereto, and the first electrode layer may be an anode and the second electrode layer may be a cathode.

[0053] The pair of gas diffusion layers 12a and 12b constituting the insert 10 may be divided into a first gas diffusion layer 12a facing a first electrode layer of the membrane-electrode assembly 11 and a second gas diffusion layer 12b facing a second electrode layer of the membrane-electrode assembly 11. The first gas diffusion layer 12a and the second gas diffusion layer 12b may be formed in the same size as the membrane-electrode assembly. However, in one embodiment, for a firm connection on the membrane electrode assembly 11 and the plate frame 100, it may be advantageous that one of the first gas diffusion layer 12a and the second gas diffusion layer 12b is formed with the same size as the membrane electrode assembly 11 and the other is formed with a size slightly smaller than the size of the membrane electrode assembly 11.For example, the first gas diffusion layer 12a may be formed with the same size as the size of the membrane electrode assembly 11, and the second gas diffusion layer 12b may be formed with a size slightly smaller than the size of the membrane electrode assembly 11.

[0054] Accordingly, the first gas diffusion layer 12a may be exposed through one surface of the edge of the insert 10, and the edge of the membrane electrode assembly 11 may be exposed through the other surface of the edge of the insert 10.

[0055] The plate frame 100 may be a structure integrally formed on the outer portion of the insert 10 for maintaining the seal of the insert 10 and simplifying a lamination process. The plate frame 100 may be formed by bonding a plurality of plates molded in a specific shape, and the respective plates may be bonded together by a separate adhesive member 200. In one embodiment, it may be advantageous for the plate frame 100 to be made of a hard plastic material having a similar thermal expansion coefficient to the partition plates 20a and 20b made of a metal material. For example, the plastic material applied to the plate frame 100 may be an engineering plastic or a high-performance plastic having a thermal expansion coefficient equal to or less than 40.

[0056] Furthermore, an adhesive or an adhesive film can be used as the adhesive element 200.

[0057] The plate frame 100 may be positioned to face one of the two surfaces of the edge of the insert 10 in the outer region of the insert 10. The plate frame 100 may be positioned to face the other of the two surfaces of the edge of the insert 10, i.e., an area with an exposed edge of the membrane electrode assembly 11. Accordingly, the plate frame 100 and the edge of the membrane electrode assembly 11 constituting the insert 10 may be bonded by the adhesive member 200.

[0058] The “outer region” of the insert 10 may be a region comprising a peripheral region of the insert 10 and a surrounding space, and the “edge” of the insert 10 may be, for example, the edge region of the insert 10.

[0059] The plate frame 100 may be configured to surround the outer region of the insert 10 while facing the other surface of the edge of the insert 10. In one embodiment, a region facing the insert 10 may be formed on the plate frame 100 for airtight bonding to the insert 10.

[0060] Furthermore, the plate frame 100 may be formed by connecting a plurality of plates.

[0061] In one embodiment of the present invention, the plate frame 100 is formed by joining three plates. For example, the plate frame 100 may be composed of a first base plate 110a and a second base plate 110b, each having a central portion on which a first insert through-hole 111a or 111b is formed, which is formed as an edge of the insert 100. The plate frame 100 may further be composed of a first flow field plate 120a bonded between the first base plate 110a and the second base plate 110b and having a central portion on which a second insert through-hole 121a communicates with the first insert through-hole 111a or 111b. Accordingly, the plate frame 100 can be formed by bonding by the adhesive member 200 in a state where the first flow field plate 120a is arranged between the first base plate 110a and the second base plate 110b.

[0062] Furthermore, a plurality of manifold through-holes for forming a manifold that allows the reaction gas and cooling water to flow into / out of the reaction region may be formed through the insert 10. The membrane electrode assembly 11 and the gas diffusion layers 12a and 12b may be formed on the plate frame 100.

[0063] For example, on each of the first base plate 110a and the second base plate 110b, a plurality of first manifold through-holes 112a and 112b may be formed on one side in a longitudinal direction based on the first insert through-hole 111a or 111b and configured to flow in and out a reaction gas and a cooling water, and a plurality of second manifold through-holes 113a and 113b may be formed on the other side in the longitudinal direction and configured to flow in and out the reaction gas and the cooling water.

[0064] Further, on the first flow field plate 120a, a plurality of third manifold through-holes 122a communicating with the plurality of first manifold through-holes 112a and 112b may be formed on one side in a longitudinal direction based on the second insert through-hole 121a, and a plurality of fourth manifold through-holes 123a communicating with the second manifold through-holes 113a and 113b may be formed on the other side in the longitudinal direction.

[0065] Furthermore, a discharge flow field 130 may be formed within the plate frame 100 to discharge generated water generated by the insert 10 along a longitudinal direction at an edge in a width direction.

[0066] The longitudinal direction of the plate frame 100 may be a direction in which the reaction gas and the cooling water flow on the plate frame 100, and the width direction of the plate frame 100, which will be described later, may be a direction perpendicular to the longitudinal direction of the plate frame 100. In some of the drawings, the longitudinal direction may be a "y" direction, and the width direction may be an "x" direction.

[0067] The pair of partition plates 20a and 20b may be structures provided to supply the reaction gas on both surfaces of the plate frame 100 and to discharge the water generated by the reaction, and may generally be made as a structure in which ridges playing a supporting role and channels (flow field) being flow paths of the reaction gas and the generated water may be repeatedly formed.

[0068] The pair of partition plates 20a and 20b may be divided into a first partition plate 20a facing the first gas diffusion layer 12a and a second partition plate 20b facing the second gas diffusion layer 12b.

[0069] On each of the two partition plates 20a and 20b, ridges and channels may be formed in the reaction region on which the insert 10 is positioned, a plurality of fifth manifold through-holes 21a and 21b through which the reaction gas and the cooling water can flow in and out may be formed on one side in the longitudinal direction based on the reaction region, and a plurality of sixth manifold through-holes 22a and 22b through which the reaction gas and the cooling water can flow in and out may be formed on the other side in the longitudinal direction.

[0070] In one embodiment, the plurality of fifth manifold through-holes 21a and 21b formed on the pair of partition plates 20a and 20b are configured to communicate with the plurality of first manifold through-holes 112a and 112b and the third manifold through-hole 122a formed on the plate frame 100, and the plurality of sixth manifold through-holes 22a and 22b formed on the pair of partition plates 20a and 20b are configured to communicate with the plurality of second manifold through-holes 113a and 113b and the fourth manifold through-hole 123a formed on the plate frame 100.

[0071] Hereinafter, a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0072] Fig. 4A and Fig. 4B are diagrams showing main part cross sections of a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure.

[0073] Fig. Figure 4A shows a cross section along line AA in Fig. 1. Fig. Figure 4B shows a cross section along line BB in Fig. 1.

[0074] As shown in the drawings, in the same manner as described above with reference to the Fig. 1 to 3, the unit cell for a fuel cell stack according to an embodiment of the present disclosure includes an insert 10 consisting of a membrane-electrode assembly 11 in which a first electrode layer is formed on one surface of a polymer electrolyte membrane and a second electrode layer is formed on the other surface of the polymer electrolyte membrane, and a pair of gas diffusion layers 12a and 12b arranged on both surfaces of the membrane-electrode assembly 11.The modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure further includes a plate frame 100 formed by joining a plurality of plates and configured to surround an edge of the cartridge 10 in an outer region of the cartridge 10, and a pair of partition plates 20a and 20b having flow fields formed on both surfaces of the plate frame 100 and configured to supply a reaction gas and discharge water generated by the reaction.

[0075] A discharge flow field 130 for discharging the generated water generated by the insert 10 may be formed within the plate frame 100 along a longitudinal direction at an edge in a width direction.

[0076] Since the insert 10 may have the same characteristics as the insert 10 having the features described above with reference to the Fig. 1 to 3, a duplicate description of the same is omitted.

[0077] Since the plate frame 100 may have a similar nature to the plate frame 100 having the features described above with reference to the Fig. 1 to 3, the duplicate description of the same is omitted.

[0078] As described above, the plate frame 100 may be formed by bonding with an adhesive member 200 in a state where a first flow field plate 120a is arranged between the first base plate 110a and the second base plate 110b.

[0079] The second insert through-hole 121a formed on the first flow field plate 120a may be formed such that an edge thereof is larger by a certain width than the first insert through-hole 111a or 111b formed on the first base plate 110a and the second base plate 110b. Accordingly, since the first base plate 110a, the second base plate 110b, and the first flow field plate 120a may be connected to each other, a step part 101 may be formed as large as the thickness of the first flow field plate 120a due to the size difference between the second insert through-hole 121a and the first insert through-hole 111a or 111b. Accordingly, the step part 101 may be formed on an inner periphery of the plate frame 100.

[0080] Accordingly, when connecting the plate frame 100 and the insert 10, the edge of the insert 10 can be bonded to the step part 101 of the plate frame 100. And in some embodiments, since the step part 101 of the plate frame 100 and the membrane electrode assembly 11 constituting the insert 10 face each other and are bonded by the adhesive member 200, a firm connection and modularization can be achieved between them.

[0081] Further, a diffusion region for inflow or outflow of the reaction gas may be formed on the plate frame 100, which diffuses between the first manifold through-hole 112a or 112b, the third manifold through-hole 122a and the first insert through-hole 111a or 111b and between the first insert through-hole 111a or 111b, the second manifold through-hole 113a or 113b and the fourth manifold through-hole 123a.

[0082] At the edge in the width direction of the plate frame 100 according to an embodiment of the present disclosure, the discharge flow field 130 for discharging the generated water generated by the insert 10 along the longitudinal direction is formed within the plate frame 100.

[0083] The discharge flow field 130 may be formed within the plate frame 100, since the plate frame 100 may be formed by joining a plurality of plates. Accordingly, in some embodiments, it is preferred that the discharge flow field 130 be formed on the first flow field plate 120a, which is disposed between the first base plate 110a and the second base plate 110b.

[0084] The discharge flow field 130 may be implemented as a first discharge flow field 130a that communicates with any one of a plurality of third manifold through-holes 122a at a position adjacent to the second insert through-hole 121a on the first flow field plate 120a.

[0085] The first discharge flow field 130a may communicate with any one of the plurality of third manifold through-holes 122a in a region where the first gas diffusion layer 12a and the first partition plate 20a come into contact with each other.

[0086] Preferably, in some embodiments, the first discharge flow field 130a communicates with the third distribution through-hole 122a positioned at a lowermost end based on a direction of gravity among the plurality of third distribution through-holes 122a. Further, the first discharge flow field 130a may be formed gradually obliquely in a downward direction toward the third distribution through-hole 122a at the lowermost end for smoothly discharging the generated water.

[0087] Accordingly, the first discharge flow field 130a may be formed at a lower part of the plate frame 100 based on the direction of gravity when the plate frame 100 is installed on the fuel cell stack.

[0088] The first discharge flow field 130a may be divided into a first main discharge flow field 130 formed along a longitudinal direction at one edge in a width direction of the plate frame 100 and having an end part communicating with any one of the plurality of third manifold through-holes 122a, and a plurality of first branched discharge flow fields 130 spaced at a certain distance from the first main discharge flow field 130 along a longitudinal direction and branched toward the second insert through-hole 121a.

[0089] Accordingly, when the generated water is generated in the reaction area on which the insert 10 is disposed and accumulates in the lower part based on the direction of gravity due to the self-weight of the generated water, the generated water can flow to the first main discharge flow field 130 through the plurality of first branched discharge flow fields 130 and can flow and be discharged through the third distribution through-hole 122a. Accordingly, in some embodiments, it is preferable that the third distribution through-hole 122a communicating with the first main discharge flow field 130 is the third distribution through-hole 122a for discharging oxygen (air), which is the reaction gas.

[0090] Since hydrogen and oxygen (air) flow independently within the fuel cell stack, the oxygen (air) can flow on one of the two surfaces of the insert 10, and the hydrogen can flow on the other surface, even in the unit cell.

[0091] Accordingly, for more effectively discharging the generated water, the discharge flow field 130 may further include a second discharge flow field 130b for discharging the generated water through the fourth distribution through-hole 123a for discharging the hydrogen together with the first discharge flow field 130a for discharging the generated water through the third distribution through-hole 122a or 122b for discharging the oxygen (air).

[0092] Fig. 5 is a diagram showing a modularized unit cell for a fuel cell stack according to an embodiment of the present disclosure.

[0093] As in Fig. 5, the second discharge flow field 130b may be formed in the same manner as the first discharge flow field 130a on the lower part of the plate frame 100 based on the direction of gravity when the plate frame 100 is installed on the fuel cell stack to smoothly discharge the generated water that accumulates on the lower part based on the direction of gravity by its own weight.

[0094] Accordingly, the first discharge flow field 130a and the second discharge flow field 130b may be formed independently of each other at corresponding positions within the plate frame 100 without communicating with each other.

[0095] However, the first discharge flow field 130a and the second discharge flow field 130b may be formed at the corresponding positions spaced apart from each other in a thickness direction of the plate frame 100. In some embodiments, it is preferable that the first discharge flow field 130a and the second discharge flow field 130b be formed in shapes that are symmetrical to each other.

[0096] Accordingly, in one embodiment of the present disclosure, the plate frame 100 is formed by joining four plates, and the plate frame 100 may, for example, consist of a first base plate 110a and a second base plate 110b, each having a central portion on which a first insert through-hole 111a or 111b is seated, which is formed as an edge of the insert 10. The plate frame 100 may further consist of a first flow field plate 120a and a second flow field plate 120b having a central portion on which a second insert through-hole 121a or 121b is formed, which communicates with the first insert through-hole 111a or 111b.Accordingly, the plate frame 100 may be configured in such a manner that the first flow field plate 120a is bonded between the first base plate 110a and the second base plate 110b, and the second flow field plate 120b is bonded to each other by the bonding member 200 in a state where the second flow field plate 120b is positioned on an outer surface of the second base plate 110b.

[0097] On the plate frame 100, a plurality of manifold through-holes for forming a manifold for flowing the reaction gas and the cooling water into and out of the reaction region may be formed through the insert 10, ie, the membrane electrode assembly 11 and the gas diffusion layers 12a and 12b.

[0098] For example, on each of the first base plate 110a and the second base plate 110b, a plurality of first manifold through-holes 112a and 112b may be formed on one side in a longitudinal direction based on the first insert through-hole 111a or 111b, and configured to allow the reaction gas and the cooling water to flow in and out. And a plurality of second manifold through-holes 113a and 113b may be formed on the other side in the longitudinal direction, and configured to allow the reaction gas and the cooling water to flow in and out.

[0099] On the first flow field plate 120a and the second flow field plate 120b, a plurality of third manifold through-holes 122a and 122b communicating with the plurality of first manifold through-holes 112a and 112b may be formed on one side in a longitudinal direction based on the second insert through-hole 121a and 121b. And a plurality of fourth manifold through-holes 123a and 123b communicating with the second manifold through-holes 113a and 113b may be formed on the other side in the longitudinal direction.

[0100] The output flow field 130 may be implemented as a first output flow field 130a communicating with any one of a plurality of third manifold through-holes 122a and 122b at a position adjacent to the second insert through-holes 121a and 121b on the first flow field plate 120a, and as a second output flow field 130b communicating with any one of a plurality of fourth manifold through-holes 122a and 122b at a position adjacent to the second insert through-holes 121a and 121b on the second flow field plate 120b.

[0101] The first discharge flow field 130a may communicate with any one of the plurality of third manifold through-holes 122a and 122b in a region where the first gas diffusion layer 12a and the first partition plate 20a come into contact with each other. And the second discharge flow field 130b may communicate with any one of the plurality of fourth manifold through-holes 123a and 123b in a region where the second gas diffusion layer 12b and the second partition plate 20b come into contact with each other.

[0102] In some embodiments, the first discharge flow field 130a may preferably communicate with the third distribution through-holes 122a and 122b positioned at a lowermost end based on a direction of gravity among the plurality of third distribution through-holes 122a and 122b. For smooth discharge of the generated water, the first discharge flow field 130a may be formed gradually obliquely in a downward direction toward the third distribution through-holes 122a and 122b at the lowermost end.

[0103] In some embodiments, it is advantageous for the second discharge flow field 130a to communicate with the fourth distribution through-holes 123a and 123b positioned at the lowermost end based on the direction of gravity among the plurality of fourth distribution through-holes 123a and 123b. For uniformly discharging the generated water, the second discharge flow field 130b may be formed gradually obliquely in the lower direction toward the fourth distribution through-holes 123a and 123b at the lowermost end.

[0104] Accordingly, the first discharge flow field 130a and the second discharge flow field 130b may be formed on the lower part of the plate frame 100 based on the direction of gravity when the plate frame 100 is installed on the fuel cell stack.

[0105] The first discharge flow field 130a may be divided into a first main discharge flow field 130 formed along a longitudinal direction at one edge in a width direction of the plate frame 100 and having an end part communicating with any one of the plurality of third manifold through-holes 122a and 122b, and a plurality of first branched discharge flow fields 130 which may be spaced at a predetermined or selected interval from the first main discharge flow field 130 along the longitudinal direction and branched toward the second insert through-holes 121a and 121b.

[0106] The second discharge flow field 130b may be divided into a second main discharge flow field 130 formed along a longitudinal direction at an edge in a width direction of the plate frame 100 and having an end part communicating with any one of the plurality of fourth manifold through-holes 123a and 123b, and a plurality of second branched discharge flow fields 130 which may be spaced at a predetermined or selected interval from the second main discharge flow field 130 along the longitudinal direction and branched toward the second insert through-holes 121a and 121b.

[0107] Accordingly, when the generated water is generated in the reaction area on which the insert 10 is disposed, and the generated water accumulates in the lower part based on the direction of gravity due to its own weight, the generated water can flow to the first main discharge flow field 130 or the second main discharge flow field 130 through the plurality of first branched flow fields 130 or the second branched flow field 130 and flow and be discharged through the third distribution through holes 122a and 122b or the fourth distribution through holes 123a and 123b. Accordingly, in some embodiments, it is preferable that the third distribution through holes 122a and 122b communicating with the first main discharge flow field 130 are the third distribution through holes 122a and 122b for discharging oxygen (air), which is the reaction gas.Further, in some embodiments, it is preferable that the fourth manifold through-holes 123a and 123b communicating with the second main discharge flow field 130 are the fourth manifold through-holes 123a and 123b for discharging hydrogen, which is the reaction gas.

[0108] Next, the position where the discharge flow field 130 may be formed on the plate frame 100 will be described in detail.

[0109] As in the Fig. 4A, Fig. 4B, Fig. 7A and Fig. As shown in Figure 7B, an adhesive region adhering to a pair of partition plates 20a and 20b may be formed along the longitudinal direction at the edge in the width direction of the plate frame 100. In some embodiments, it is preferable that the adhesive region be formed on a non-reactive region where no chemical reaction between hydrogen and oxygen occurs.

[0110] In particular, in some embodiments, it is advantageous that on any one of the pair of separating plates 20a and 20b, a seal 30 surrounding the area in which the insert 10 is arranged is provided in the adhesive area of ​​the plate frame 100.

[0111] The seal 30 may be provided to form a seal from external gases and cooling water in the unit cell structure.

[0112] Accordingly, in some embodiments, it is advantageous that the discharge flow field 130 is formed within the bonding area of ​​the plate frame 100, and in particular, in some embodiments, it is advantageous that the discharge flow field 130 is formed in the area between an outermost angle of the insert 10 and the position at which the seal 30 is provided.

[0113] The plate frame 100 and the pair of partition plates 20a and 20b may be bonded to each other by the bonding member 200 in the bonding area, and since a part capable of directly pressing the partition plates 20a and 20b may be provided to improve bonding force, it is preferable in some embodiments to provide a bonding area in a region except for the region where the gasket 30 is provided.

[0114] When the discharge flow field 130 is formed up to the position where the seal 30 is provided during stack fixation, there may be a possibility that the cross section of the discharge flow field 130 narrows due to the reaction force of the seal 30 and the operating temperature, and therefore, in some embodiments, it is preferable that the formation position of the discharge flow field 130 is limited to be between the outermost angle of the insert 10 and the position where the seal 30 is provided.

[0115] Although embodiments of the present disclosure have been described with reference to the accompanying drawings, the present disclosure is not necessarily limited thereto. Accordingly, those skilled in the art to which this disclosure pertains will recognize that various changes and corrections may be possible without departing from the technical spirit of the claims.

Claims

[1] Modularized unit cell of a fuel cell stack, the modularized unit cell comprising: an insert formed from a membrane-electrode assembly, wherein a first electrode layer is formed on a first surface of a polymer electrolyte membrane and a second electrode layer is formed on a second surface of the polymer electrolyte membrane, the first surface facing the second surface, a first gas diffusion layer on the first surface of the membrane-electrode assembly and a second gas diffusion layer on the second surface of the membrane-electrode assembly; a plate frame comprising a plurality of interconnected plates, configured to surround an edge of the insert in an outer region of the insert, connected at the edge of the insert and an interface thereof, and having a discharge flow field formed therein along a longitudinal direction near an edge in a width direction for discharging water generated by the insert; and a pair of partition plates having flow fields formed on both surfaces of the plate frame and configured to supply a reaction gas and discharge water generated by a reaction. [2] The cell of claim 1, wherein the plurality of plates of the plate frame are formed of: a first base plate and a second base plate, each having a base plate center region on which a first insert through-hole is configured as an edge for receiving the insert; and a first flow field plate bonded between the first base plate and the second base plate, the first flow field plate having a field plate center portion on which a second insert through-hole communicating with the first insert through-hole is formed, wherein the discharge flow field is formed on the first flow field plate. [3] The cell according to claim 2, wherein on the first base plate and the second base plate, a plurality of first manifold through-holes are formed on a first base plate side in the longitudinal direction based on the first insert through-hole and are configured to flow in and out a reaction gas and a cooling water, and a plurality of second manifold through-holes are formed on a second base plate side in the longitudinal direction and are configured to flow in and out the reaction gas and the cooling water, wherein on the first flow field plate, a plurality of third distributor through-holes communicating with the plurality of first distributor through-holes are formed on a first flow field plate side in the longitudinal direction based on the second insert through-hole, and a plurality of fourth distributor through-holes communicating with the second distributor through-holes are formed on a second flow field plate side in the longitudinal direction, and wherein the discharge flow field comprises a first discharge flow field communicating with any one of the plurality of third manifold through-holes from a position adjacent to the second insert through-hole on the first flow field plate. [4] The cell of claim 3, wherein the first gas diffusion layer faces the first electrode layer of the membrane-electrode assembly and the second gas diffusion layer faces the second electrode layer of the membrane-electrode assembly, wherein the pair of partition plates comprises a first partition plate facing the first gas diffusion layer and a second partition plate facing the second gas diffusion layer, and wherein the first discharge flow field communicates with any one of the plurality of first manifold through-holes in a region where the first gas diffusion layer and the first partition plate come into contact with each other. [5] The cell according to claim 4, wherein the first discharge flow field comprises a first main discharge flow field formed along the longitudinal direction near the edge in the width direction of the plate frame and having an end part communicating with any one of the plurality of third manifold through-holes, and wherein a plurality of first branched discharge flow fields are spaced at a selected interval from the first main discharge flow field along the longitudinal direction and branched toward the second insert through-hole. [6] The cell according to claim 5, wherein the first main discharge flow field communicates with the third manifold through-hole located at a lowermost end based on a direction of gravity among the plurality of third manifold through-holes. [7] The cell of claim 2, wherein the second insert through-hole is formed such that a hole edge thereof is larger than the first insert through-hole by a selected width, wherein, due to a difference in size between the second insert through-hole and the first insert through-hole, a step part equal to the thickness of the first flow field plate is formed when the first base plate, the second base plate, and the first flow field plate are connected to each other; and whereby one edge of the insert is glued to the step part. [8] The cell of claim 1, wherein a seal surrounds the insert on any one of the pair of partition plates, and wherein the discharge flow field is formed between an outermost angle of the insert and a position at which the seal is provided. [9] The cell according to claim 1, wherein the plate frame is formed of an engineering plastic or a high-performance plastic having a thermal expansion coefficient equal to or less than 40. [10] Modularized unit cell of a fuel cell stack, the modularized unit cell comprising: an insert formed from a membrane-electrode assembly, wherein a first electrode layer is formed on a first surface of a polymer electrolyte membrane and a second electrode layer is formed on a second surface of the polymer electrolyte membrane, the first surface facing the second surface, a first gas diffusion layer on the first surface of the membrane-electrode assembly and a second gas diffusion layer on the second surface of the membrane-electrode assembly; a plate frame comprising a plurality of interconnected plates, configured to surround an edge of the insert in an outer region of the insert, connected at the edge of the insert and an interface thereof, and having a discharge flow field formed therein along a longitudinal direction near an edge in a width direction for discharging water generated by the insert; and a pair of partition plates with flow fields formed on both surfaces of the plate frame and configured to supply a reaction gas and discharge water generated by a reaction, wherein the plurality of plates of the plate frame are formed from: a first base plate and a second base plate, each having a base plate center region on which a first insert through-hole is configured as an edge for receiving the insert; and a first flow field plate and a second flow field plate, each having a field plate center region on which a second insert through-hole communicating with the first insert through-hole is formed, wherein the first flow field plate is glued between the first base plate and the second base plate, wherein the second flow field plate is bonded to an outer surface of the second base plate, and wherein the output flow field comprises a first output flow field formed on the first flow field plate and a second output flow field formed on the second flow field plate. [11] The cell according to claim 10, wherein on each of the first base plate and the second base plate, a plurality of first manifold through-holes are formed on a first plate side in the longitudinal direction based on the first insert through-hole and are configured to flow in and out a reaction gas and a cooling water, and a plurality of second manifold through-holes are formed on a second plate side in the longitudinal direction and are configured to flow in and out the reaction gas and the cooling water; wherein, on each of the first flow field plate and the second flow field plate, a plurality of third manifold through-holes communicating with the plurality of first manifold through-holes are formed on a first field plate side in the longitudinal direction based on the second insert through-hole, and a plurality of fourth manifold through-holes communicating with the second manifold through-holes are formed on a second field plate side in the longitudinal direction; and wherein the output flow field comprises a first output flow field communicating with any one of the plurality of third manifold through-holes from a position adjacent to the second insert through-hole on the first flow field plate, and a second output flow field communicating with any one of the plurality of fourth manifold through-holes from a position adjacent to the second insert through-hole on the second flow field plate. [12] The cell of claim 11, wherein the first gas diffusion layer faces the first electrode layer of the membrane-electrode assembly and the second gas diffusion layer faces the second electrode layer of the membrane-electrode assembly, wherein the pair of partition plates comprises a first partition plate facing the first gas diffusion layer and a second partition plate facing the second gas diffusion layer, wherein the first discharge flow field communicates with any one of the plurality of third distributor through-holes in a region where the first gas diffusion layer and the first partition plate come into contact with each other, and wherein the second discharge flow field communicates with any one of the plurality of fourth manifold through-holes in a region where the second gas diffusion layer and the second partition plate come into contact with each other. [13] The cell of claim 12, wherein the first output flow field comprises: a first main discharge flow field formed along the longitudinal direction near the edge in the width direction of the plate frame and having an end portion communicating with any one of the plurality of third manifold through-holes; and a plurality of first branched discharge flow fields spaced at a predetermined interval from the first main discharge flow field along the longitudinal direction and branched toward the second insert through-hole, and where the second output flow field is divided into: a second main discharge flow field formed along the longitudinal direction at one edge in the width direction of the plate frame and having an end portion communicating with any one of the plurality of fourth manifold through-holes; and a plurality of second branched discharge flow fields spaced at a predetermined interval from the second main discharge flow field along the longitudinal direction and branched toward the second insert through-hole. [14] The cell according to claim 13, wherein the first main discharge flow field communicates with the third manifold through-hole located at a lowermost end based on a direction of gravity among the plurality of third manifold through-holes, and wherein the second main discharge flow field communicates with the fourth manifold through-hole located at a lowermost end based on the direction of gravity among the plurality of fourth manifold through-holes. [15] The cell according to claim 10, wherein the first discharge flow field and the second discharge flow field are formed independently of each other at opposite positions based on the second base plate. [16] The cell of claim 10, wherein a seal surrounds the insert on any one of the pair of partition plates, and wherein the discharge flow field is formed between an outermost angle of the insert and a position at which the seal is provided. [17] The cell of claim 10, wherein the plate frame is formed of an engineering plastic or a high-performance plastic having a thermal expansion coefficient equal to or less than 40.

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