Fuel cell separator and fuel cell stack

Abstract

To provide a separator for a fuel cell, minimizing a differential pressure while ensuring the smooth flows of a reactant gas and a coolant.SOLUTION: The present invention relates to a separator for a fuel cell, which is capable of improving performance and operational efficiency by including: a plate body 110 stacked on a gas diffusion layer and including a flow path part to define a reaction region to react with a membrane electrode assembly and manifold parts provided so as to be spaced apart from the flow path part; through-holes 112 formed in the plate body 110 to guide target fluids that have passed through the manifold parts to the flow path part; and hole caps 120 disposed on one surface of the plate body 110 that faces the gas diffusion layer to at least partially cover the through-holes 112, the hole caps defining movement paths through which the target fluids move.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the present invention relate to a separator for a fuel cell and a fuel cell stack, and more particularly to a separator for a fuel cell and a fuel cell stack that can improve performance and operating efficiency. [Background technology]

[0002] A fuel cell stack is a type of power generation device that generates electrical energy through a chemical reaction of fuel (e.g., hydrogen), and can be configured by stacking tens or hundreds of fuel cell cells (unit cells) in series.

[0003] A fuel cell includes a membrane electrode assembly (MEA) that combines an electrolyte membrane capable of transporting hydrogen cations and electrodes (catalytic electrode layers) on both sides of the electrolyte membrane to allow hydrogen and oxygen to react, gas diffusion layers (GDLs) that are in close contact with both sides of the membrane electrode assembly to uniformly distribute the reactant gases and transmit the generated electrical energy, and a separator (bipolar plate) that is in close contact with the gas diffusion layers to form a flow path.

[0004] Separators can be divided into anode separators that supply hydrogen as a fuel and cathode separators that supply air as an oxidant, and each separator includes a channel through which the fuel or oxidant flows. Furthermore, in order to stack fuel cells to form a fuel cell stack, airtightness must be maintained between the membrane electrode assembly and the reaction surface of the separator, as well as between the cooling surface of the separator.

[0005] For this purpose, gaskets are provided between the membrane electrode assembly and the reaction surfaces of the separators and between the reaction surfaces of the separators and the cooling surfaces of the separators to prevent reactant gases (e.g., hydrogen and air) flowing on the reaction surfaces of the separators and cooling water flowing on the cooling surfaces of the separators from leaking outside the fuel cell stack.

[0006] The gaskets may be integrally injection molded onto both end portions of the separator and both end portions of the manifold through which the reactant gases and the coolant flow in and out, and the gaskets may define flow paths for the reactant gases and the coolant. Meanwhile, to ensure airtightness when stacking fuel cells, a sufficient clamping pressure must be applied to the fuel cells with the gaskets provided.

[0007] However, conventional fuel cell assemblies have a problem in that the gaskets on both sides of the separators are deformed (over-compressed) when a clamping pressure (pressure) is applied to the fuel cell. In particular, the over-compression of the gaskets around the through-holes, which guide the reactant gas (or coolant) flowing in through the manifold flow path to the reaction region of the separator, makes it difficult to ensure a sufficient flow path (cross-sectional area of ​​the flow path) for the reactant gas and coolant, and makes it difficult for the reactant gas and coolant to be smoothly supplied to the reaction region of the separator (the channel between the inlet manifold and the outlet manifold).

[0008] Furthermore, in the past, the through-holes of the separator were completely covered by the gas diffusion layer (the gas diffusion layer penetrated into the through-holes to block them), so the reactant gas flowing into the through-holes had to pass through the compressed gas diffusion layer to move to the reaction region, which resulted in a decrease in the fluidity and flow efficiency of the reactant gas (or cooling water) passing through the through-holes and an increase in the differential pressure between both ends (inlet and outlet ends) of the manifold flow path.

[0009] Therefore, various studies have been conducted recently to minimize the pressure difference while ensuring smooth flow of the reaction gas and the cooling water, but the results are still insufficient, and further development is required. Summary of the Invention [Problem to be solved by the invention]

[0010] SUMMARY OF THE INVENTION An object of the present invention is to provide a separator for a fuel cell and a fuel cell stack that can ensure smooth flow of reactant gases and coolant, thereby improving safety and reliability.

[0011] In particular, an embodiment of the present invention aims to ensure stable flow of reactant gases and coolant in through-holes that guide the reactant gases and coolant that flow in through manifold channels of a separator to a reaction region, thereby improving flow efficiency.

[0012] Another object of the embodiment of the present invention is to suppress excessive compression (deformation) of the sealing member and to stably ensure a flow path area through which the reaction gas and cooling water that have passed through the through-holes move.

[0013] Another object of the embodiment of the present invention is to ensure the airtightness (fastening pressure) of the fuel cell while ensuring the flow of reactant gases and cooling water.

[0014] Another object of the present invention is to simplify the structure and manufacturing process, thereby reducing manufacturing costs.

[0015] Another object of the embodiment of the present invention is to minimize the distribution deviation (flow rate deviation) of the reactant gas cooling water and ensure stable output performance.

[0016] The problems to be solved in the embodiments are not limited to these, and may also include the means for solving the problems described below and the objectives and effects that can be grasped from the embodiments. [Means for solving the problem]

[0017] According to a preferred embodiment of the present invention for achieving the above-mentioned object of the present invention, a fuel cell separator laminated on a gas diffusion layer provided on a membrane electrode assembly (MEA) includes a flow path portion defining a reaction region that reacts with the membrane electrode assembly and a manifold portion provided to be spaced apart from the flow path portion, a plate body laminated on the gas diffusion layer, through-holes formed in the plate body for guiding a target fluid that has passed through the manifold portion to the flow path portion, and hole caps provided on one side of the plate body facing the gas diffusion layer so as to cover at least a portion of the through-holes and define a movement flow path through which the target fluid moves.

[0018] This is to ensure the smooth flow of reactant gases and coolant and improve safety and reliability. That is, in the past, when a clamping pressure (pressure) was applied to the fuel cell, the gaskets on both sides of the separator were deformed (over-compressed), and in particular, the gaskets (sealing members) around the through holes that guide the reactant gases (or coolant) that flowed in through the manifold flow paths to the reaction region of the separator were over-compressed. This made it difficult to ensure a sufficient flow path (cross-sectional area of ​​the flow paths) for the reactant gases and coolant, and made it difficult for the reactant gases and coolant to be smoothly supplied to the reaction region of the separator (the channel between the inlet manifold and the outlet manifold).

[0019] Furthermore, in the past, the through-holes of the separator were completely covered by the gas diffusion layer (the gas diffusion layer penetrated into the through-holes to block them), so the reactant gas flowing into the through-holes had to pass through the compressed gas diffusion layer to move to the reaction region, which resulted in a decrease in the fluidity and flow efficiency of the reactant gas (or cooling water) passing through the through-holes and an increase in the differential pressure between both ends (inlet and outlet ends) of the manifold flow path.

[0020] However, in an embodiment of the present invention, a hole cap is provided to cover the through-hole, and the hole cap defines a flow path that is not blocked by the gas diffusion layer, thereby ensuring the fluidity and flow efficiency of the reactant gas (or cooling water) passing through the through-hole, and ensuring stable output performance of the fuel cell stack.

[0021] Furthermore, according to an embodiment of the present invention, by supporting the gas diffusion layer with the hole cap, it is possible to prevent excessive compression of the sealing material provided around the through-hole, thereby achieving the advantageous effect of ensuring sufficient flow paths (cross-sectional area of ​​the flow path) for the reactant gas and cooling water while ensuring the airtightness (fastening pressure) of the fuel cell.

[0022] According to a preferred embodiment of the present invention, a separator for a fuel cell may include a sealing member provided on a plate body to seal the gap between adjacent through holes and defining a distribution channel that connects the flow path portion and the through holes to communicate with each other, and a hole cap may be positioned inside the distribution channel.

[0023] The hole cap may be provided in various structures having a transfer channel. According to a preferred embodiment of the present invention, the hole cap may include a side cap portion provided on the edge of the through hole and a top cap portion supported on the side cap portion so as to cover the through hole while being spaced apart from the plate body, and the transfer channel may be defined in a space between the top cap portion and the plate body. According to a preferred embodiment of the present invention, the transfer channel may be defined parallel to the plate body.

[0024] According to a preferred embodiment of the present invention, the hole caps may be integrally formed with the plate body by partially processing a portion of the plate body. In this manner, the embodiment of the present invention can obtain advantageous effects of simplifying the structure and manufacturing process and reducing costs by molding the hole caps together with the separator (flow path molding process).

[0025] According to a preferred embodiment of the present invention, the fuel cell separator may include side holes formed through the wall surfaces of the side cap portions. By providing the side holes in the side cap portions, the present invention can ensure a smooth flow of the target fluid passing through the through holes and can advantageously reduce the generation of differential pressure in the through holes.

[0026] According to a preferred embodiment of the present invention, the fuel cell separator may include a reinforcing portion that supports the hole cap relative to the plate body. The reinforcing portion may be provided in various structures that can support the hole cap relative to the plate body.

[0027] According to a preferred embodiment of the present invention, the reinforcing portion may be provided inside the through hole and may include a center reinforcing member connected to an inner surface of the top cap portion, a first side reinforcing member having one end connected to one side of the center reinforcing member and the other end connected to the plate body, and a second side reinforcing member having one end connected to the other side of the center reinforcing member and the other end connected to the plate body.

[0028] Preferably, the first side reinforcing member and the second side reinforcing member may be provided in plurality, spaced apart along the length of the center reinforcing member. In this way, by providing a plurality of first side reinforcing members and second side reinforcing members spaced apart along the length of the center reinforcing member, the embodiment of the present invention can more stably support the center reinforcing member while ensuring a smooth flow of the target fluid.

[0029] According to a preferred embodiment of the present invention, a fuel cell separator may include a center hole formed in the center reinforcing member so as to penetrate one side and the other side of the center reinforcing member. By forming the center hole in the center reinforcing member, an embodiment of the present invention can advantageously minimize a decrease in the flow of a target fluid due to the center reinforcing member being provided inside a hole cap.

[0030] According to another preferred aspect of the present invention, a fuel cell stack includes a membrane electrode assembly (MEA), a gas diffusion layer stacked on the membrane electrode assembly, a plate body stacked on the gas diffusion layer, the plate body including a flow path portion defining a reaction region that reacts with the membrane electrode assembly and a manifold portion spaced apart from the flow path portion, and the plate body having through-holes formed in the plate body and guiding a target fluid that has passed through the manifold portion to the reaction region, and a separator including hole caps that are provided on one side of the plate body opposite the gas diffusion layer to cover at least a portion of the through-holes and define a flow path through which the target fluid moves.

[0031] According to another preferred aspect of the present invention, the hole cap includes a side cap portion provided on the edge of the through hole, and a top cap portion supported on the side cap portion so as to cover the through hole and be spaced apart from the plate body, and the movement flow path can be defined in the space between the top cap portion and the plate body.

[0032] According to another preferred aspect of the present invention, the fuel cell stack may include a side hole formed through the wall of the side cap portion.

[0033] According to another preferred aspect of the present invention, the fuel cell stack may include a reinforcing portion that supports the hole cap relative to the plate body.

[0034] According to another preferred aspect of the present invention, the reinforcing portion may include a center reinforcing member connected to the inner surface of the top cap portion, a first side reinforcing member having one end connected to one side of the center reinforcing member and the other end connected to the plate body, and a second side reinforcing member having one end connected to the other side of the center reinforcing member and the other end connected to the plate body.

[0035] According to another preferred aspect of the present invention, the fuel cell stack may include a center hole formed in the center reinforcing member so as to penetrate one side and the other side of the center reinforcing member.

[0036] According to another preferred aspect of the present invention, the fuel cell stack may include a sealing member provided on the plate body to seal the space between adjacent through holes and defining a distribution channel that connects the flow path portion and the through holes to communicate with each other, and a hole cap may be positioned inside the distribution channel.

[0037] According to another preferred aspect of the present invention, the hole cap may be integrally formed with the plate body by partially machining a part of the plate body. [Brief explanation of the drawings]

[0038] [Figure 1] 1 is a diagram illustrating a fuel cell stack according to an embodiment of the present invention; [Figure 2] 1 is a cross-sectional view illustrating a fuel cell stack according to an embodiment of the present invention. [Figure 3] 1 is a diagram illustrating a separator in a fuel cell stack according to an embodiment of the present invention; [Figure 4] 1 is a diagram illustrating a separator in a fuel cell stack according to an embodiment of the present invention; [Figure 5] 3 is a diagram illustrating a fuel cell stack according to an embodiment of the present invention, for explaining a side hole. FIG. [Figure 6]3 is a diagram illustrating a fuel cell stack according to an embodiment of the present invention, for explaining a side hole. FIG. [Figure 7] 3A and 3B are diagrams illustrating a fuel cell stack according to an embodiment of the present invention, illustrating a reinforcing portion. [Figure 8] 3A and 3B are diagrams illustrating a fuel cell stack according to an embodiment of the present invention, illustrating a reinforcing portion. [Figure 9] 3A and 3B are diagrams illustrating a fuel cell stack according to an embodiment of the present invention, illustrating a reinforcing portion. DETAILED DESCRIPTION OF THE INVENTION

[0039] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, the technical concept of the present invention is not limited to some of the described embodiments, and may be realized in various different forms. One or more of the components of the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention.

[0040] Furthermore, unless otherwise clearly defined and described, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that are commonly understood by a person of ordinary skill in the art to which the present invention belongs, and commonly used terms such as predefined terms may be interpreted in light of the contextual meaning of the relevant art.

[0041] The terms used in the embodiments of the present invention are intended to explain the embodiments and are not intended to limit the present invention.

[0042] In this specification, unless otherwise specified in the context, the singular form can also include the plural form, and when it is stated that "A and (and) at least one (or more) of B and C" it can include one or more of all possible combinations of A, B, and C. Furthermore, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. can be used.

[0043] Such terms are used only to distinguish a component from other components, and are not intended to limit the essence, order, or sequence of the components.

[0044] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it includes not only the case where the component is directly coupled, coupled, or connected to the other component, but also the case where the component is "coupled," "coupled," or "connected" by yet another component between the component and the other component.

[0045] Furthermore, when described as being formed or disposed "above or below" each component, above or below includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. Furthermore, when described as "above or below," it can mean not only the upper direction based on one component, but also the lower direction.

[0046] 1 to 9, a fuel cell stack 10 according to an embodiment of the present invention includes a membrane electrode assembly (MEA) 300, a gas diffusion layer 200 stacked on the membrane electrode assembly 300, a plate body 110 stacked on the gas diffusion layer 200, the plate body 110 including a flow path portion 101 defining a reaction region that reacts with the membrane electrode assembly 300 and a manifold portion 102 spaced apart from the flow path portion 101, through holes 112 formed in the plate body 110 for guiding a target fluid (e.g., a reactant gas and a cooling water) that has passed through the manifold portion 102 to the reaction region, and a separator 100 including a hole cap 120 disposed on one side of the plate body 110 facing the gas diffusion layer 200 to cover at least a portion of the through hole 112 and defining a transfer flow path 120a through which the target fluid moves.

[0047] For reference, the fuel cell stack 10 may be constructed by stacking a plurality of unit cells in a reference direction (e.g., vertically). A fuel cell (unit cell) may include a reaction layer (not shown) and separators 100 stacked on both sides of the reaction layer. After stacking a plurality of fuel cells in the reference direction, the fuel cell stack 10 may be constructed by assembling end plates (not shown) on both ends of the stack.

[0048] More specifically, the reaction layer may include a membrane electrode assembly (MEA) 300 and gas diffusion layers (GDL) 200 that are in close contact with both sides of the membrane electrode assembly 300.

[0049] The membrane electrode assembly 300 is configured to produce electricity through an oxidation-reduction reaction between a first reactant gas, a fuel (e.g., hydrogen), and a second reactant gas, an oxidant (e.g., air). The structure and materials of the membrane electrode assembly 300 may be variously changed according to required conditions and design specifications, and the present invention is not limited or restricted by the structure and materials of the membrane electrode assembly 300. For example, the membrane electrode assembly 300 may be configured by attaching catalyst electrode layers, where an electrochemical reaction occurs, to both sides of an electrolyte membrane, centered around an electrolyte membrane through which protons move.

[0050] Gas diffusion layers (GDLs) 200 are laminated on both sides of the membrane electrode assembly 300 and serve to uniformly distribute reactant gases and transmit generated electrical energy. The GDLs 200 may be provided in various structures capable of diffusing reactant gases. For example, the GDLs 200 may be provided in a porous structure having pores of a predetermined size. The pore size and material of the GDLs 200 may vary depending on required conditions and design specifications, and the present invention is not limited or restricted by the pore size and material of the GDLs 200.

[0051] The separator 100 is provided to separate the reactant gases hydrogen and air, as well as to ensure the flow paths of the reactant gases and coolant and to transmit current to an external circuit. The separator 100 also distributes heat generated in the fuel cell (unit cell) throughout the fuel cell, and excess heat can be discharged to the outside by the coolant flowing along the cooling channel of the separator 100.

[0052] In an embodiment of the present invention, the separator 100 can be defined as including both an anode separator that forms a flow path for hydrogen as a fuel, and a cathode separator that forms a flow path for air as an oxidant.

[0053] For reference, hydrogen as a fuel and air as an oxidant are supplied to the anode (not shown) and cathode (not shown) of the membrane electrode assembly 300, respectively, through channels in the separator 100 (cathode separator and anode separator), and hydrogen can be supplied to the anode and air can be supplied to the cathode.

[0054] Hydrogen supplied to the anode is decomposed into protons and electrons by the catalyst in the electrode layers on both sides of the electrolyte membrane, and only the protons are selectively transferred to the cathode through the electrolyte membrane, which is a cation exchange membrane. At the same time, the electrons are transferred to the cathode through the gas diffusion layer 200 and separator 100, which are conductors.

[0055] At the cathode, hydrogen ions supplied through the electrolyte membrane and electrons transferred through the separator 100 come into contact with oxygen in the air supplied to the cathode by an air supply device, and a reaction occurs to produce water. The movement of hydrogen ions generated at this time causes a flow of electrons through an external conductor, and this flow of electrons generates an electric current.

[0056] The separator 100 is provided to supply a first reaction gas (e.g., hydrogen) and a second reaction gas (e.g., air) to the membrane electrode assembly 300, and is arranged to be in close contact with one side and the other side (the outer surface of the gas diffusion layer) of the membrane electrode assembly 300 based on the stacking direction of the fuel cell cells.

[0057] More specifically, the separator 100 includes a plate body 110 stacked on the gas diffusion layer 200, which includes a flow path portion 101 defining a reaction region that reacts with the membrane electrode assembly 300 and a manifold portion 102 spaced apart from the flow path portion 101, through-holes 112 formed in the plate body 110 and guiding the target fluid that has passed through the manifold portion 102 to the flow path portion 101, and hole caps 120 provided on one side of the plate body 110 facing the gas diffusion layer 200 to cover at least a portion of the through-holes 112 and defining a transfer flow path 120a through which the target fluid moves.

[0058] The plate body 110 may be formed from a flat, thin plate, and the present invention is not limited or restricted by the size, material, or structure of the plate body 110. For example, the plate body 110 may be formed in the shape of a flat, approximately rectangular plate and may be formed from a common metal material (e.g., stainless steel, Inconel, or aluminum). According to other embodiments of the present invention, the plate body may be formed from other materials, such as graphite or a carbon composite material.

[0059] A flow path portion 101 that defines a reaction region is formed in the approximate center of the plate body 110 so as to face one surface of the membrane electrode assembly 300. The flow path portion 101 may include a plurality of flow paths (channels) (not shown) that are spaced apart from each other, and the present invention is not limited or restricted by the number and arrangement of the flow paths.

[0060] Manifold units 102 (e.g., a hydrogen manifold, a cooling water manifold, and an air manifold) for flowing (supplying and discharging) hydrogen, air, and coolant are formed through both ends of the separator 100 with the flow path unit 101 sandwiched therebetween. For example, a first manifold (not shown) may be formed at one end of the separator 100 so as to be spaced apart from one end of the flow path unit 101, and a second manifold (not shown) may be formed at the other end of the separator 100 so as to be spaced apart from the other end of the flow path unit 101.

[0061] Preferably, a target fluid (e.g., a reactant gas or a coolant) may flow into one of the first and second manifolds, and the target fluid may be discharged from the other of the first and second manifolds. For example, the first manifold may include a hydrogen inlet manifold to which hydrogen is supplied, a coolant inlet manifold to which coolant is supplied, and an air outlet manifold to which air is discharged. Also, the second manifold may include a hydrogen outlet manifold to which hydrogen is discharged, a coolant outlet manifold to which coolant is discharged, and an air inlet manifold to which air is supplied.

[0062] The structure and shape of the manifold portion 102 can be variously changed depending on the required conditions and design specifications, and the present invention is not limited or restricted by the structure and shape of the manifold portion 102. As an example, the hydrogen inlet manifold, the coolant inlet manifold, and the air outlet manifold may be formed to penetrate one end of the separator 100 so as to have a substantially trapezoidal or triangular shape. Similarly, the hydrogen outlet manifold, the coolant outlet manifold, and the air inlet manifold may be formed to penetrate the other end of the separator 100 so as to have a substantially trapezoidal or triangular shape.

[0063] Further, the plate body 110 is provided with a through-hole 112 located between the manifold portion 102 and the flow path portion 101. The through-hole 112 is formed to penetrate the plate body 110 so as to guide the target fluid that has passed through the manifold portion 102 to the flow path portion 101.

[0064] As an example, a reactant gas (e.g., hydrogen) supplied through the manifold unit 102 (e.g., a hydrogen inlet manifold) can be supplied to the through-holes 112 along a transfer path (not shown) defined on one side of the separator 100 (e.g., the bottom side in FIG. 2), and the reactant gas passing through the through-holes 112 can be supplied to the flow path unit 101 along a distribution channel 132 defined on the other side of the separator 100 (e.g., the top side in FIG. 2).

[0065] The through-hole 112 may be formed in various shapes depending on the required conditions and design specifications, and the present invention is not limited or restricted by the structure and shape of the through-hole 112. For example, the through-hole 112 may be formed in the shape of an elongated hole having a length greater than its width. Alternatively, the through-hole 112 may be formed in a circular or other shape.

[0066] According to a preferred embodiment of the present invention, the fuel cell stack 10 may include a sealing member 130 provided on the plate body 110 to seal the space between adjacent through holes 112 and defining a distribution channel 132 that connects the flow path portion 101 and the through holes 112 to communicate with each other.

[0067] The sealing member 130 is provided on the plate body 110 to seal the gap between the membrane electrode assembly 300 and the separator 100 and also to seal the gap between adjacent through-holes 112. A plurality of distribution channels 132 may be defined between the membrane electrode assembly 300 and the separator 100 via the sealing member 130, connecting the flow path portion 101 and the through-holes 112 to communicate with each other. In addition, the hole caps 120 may be provided to be positioned inside the distribution channels 132.

[0068] A plurality of distribution channels 132 are provided at predetermined intervals for each through hole 112, and one end of each distribution channel 132 communicates with the manifold unit 102 via the through hole 112, and the other end of each distribution channel 132 communicates with the flow path unit 101. The number, width, and spacing of the distribution channels 132 may be varied in various ways depending on required conditions and design specifications, and the present invention is not limited or restricted by the number, width, and spacing of the distribution channels 132.

[0069] The sealing member 130 may be formed in various ways depending on required conditions and design specifications, and the present invention is not limited or restricted by the method of manufacturing the sealing member 130. As an example, the sealing member 130 may be formed by applying, transferring, or printing a sealant made of an elastic material such as rubber, silicone, or urethane onto the surface of the plate body 110.

[0070] According to other embodiments of the present invention, the sealing member can be injection molded onto the plate body, or the sealing member can be made (e.g., injection molded) separately from the plate body and then attached (glued) to the plate body.

[0071] 2 to 4, the hole cap 120 is provided on one side of the plate body 110 facing the gas diffusion layer 200 so as to cover at least a portion of the through-hole 112, and a transfer flow path 120a through which the target fluid (reactant gas or cooling water) moves is defined between the gas diffusion layer 200 and the plate body 110 via the hole cap 120.

[0072] The hole caps 120 are provided to stably ensure the fluidity and flow efficiency of the target fluid passing through the through-holes 112. That is, in the conventional technology, when a separator is stacked on the gas diffusion layer, the through-holes are completely covered by the gas diffusion layer (the gas diffusion layer penetrates into the through-holes to block them), so the reactant gas that flows into the through-holes has to pass through the gas diffusion layer in a compressed state to move to the reaction region, which causes a problem of reduced fluidity and flow efficiency of the target fluid.

[0073] Furthermore, in the past, when clamping pressure was applied to a separator stacked on a gas diffusion layer, the sealing material around the through-holes was over-compressed, reducing the width of the distribution channel (see L1 in Figure 3). This made it difficult to secure a sufficient flow path (cross-sectional area of ​​the flow path) for the target fluid (reactant gas and cooling water), making it difficult to smoothly supply the target fluid to the reaction region of the separator (plate body).

[0074] However, in an embodiment of the present invention, a hole cap 120 is provided to cover the through-hole 112, and the hole cap 120 defines a movement flow path 120a that is not blocked by the gas diffusion layer 200, thereby ensuring the fluidity and flow efficiency of the reactant gas (or cooling water) passing through the through-hole 112 and ensuring stable output performance of the fuel cell stack 10.

[0075] Furthermore, according to an embodiment of the present invention, when a clamping pressure is applied to the fuel cell stack 10, the hole cap 120 can prevent the sealing member 130 provided around the through-hole 112 from being excessively compressed (the hole cap prevents the sealing member from being compressed beyond a certain level, thereby maintaining the width of the distribution channel), thereby achieving the advantageous effect of ensuring sufficient flow paths (cross-sectional area of ​​the flow paths) for the reactant gases and coolant while ensuring airtightness of the fuel cell. Therefore, it is possible to minimize the flow rate deviation of the target fluids supplied to each flow path of the flow path unit 101, thereby achieving the advantageous effect of ensuring stable and uniform output performance of the fuel cell stack 10.

[0076] The hole cap 120 may be provided in various structures having the transfer channel 120a, and the present invention is not limited or restricted by the structure and form of the hole cap 120. According to a preferred embodiment of the present invention, the hole cap 120 may include a side cap portion 122 provided on the edge of the through-hole 112, and a top cap portion 124 supported by the side cap portion 122 so as to be spaced apart from the plate body 110 and cover the through-hole 112, and the transfer channel 120a may be defined in the space between the top cap portion 124 and the plate body 110.

[0077] For reference, in the embodiment of the present invention, the transfer channel 120a can be understood as an empty space defined along the interior of the hole cap 120. The transfer channel 120a may be formed in various structures depending on required conditions and design specifications. According to a preferred embodiment of the present invention, the transfer channel 120a may be defined substantially parallel to the plate body 110. According to other embodiments of the present invention, the transfer channel may be formed in a curved shape or in other shapes.

[0078] The side cap portion 122 may be formed in various structures having an opening communicating with the flow path portion 101 (distribution channel). According to a preferred embodiment of the present invention, the side cap portion 122 may be formed continuously along the edge of the through-hole 112. As an example, the side cap portion 122 may be formed in a continuous "C" shape along the edge of the through-hole 112.

[0079] In the embodiment of the present invention described above and illustrated, an example is given in which the side cap portion 122 is formed in a continuous strip shape. However, according to other embodiments of the present invention, it is also possible to provide a plurality of side cap portions spaced apart along the edge of the through hole.

[0080] The top cap portion 124 is supported on the end of the side cap portion 122 so as to be spaced apart from the plate body 110, and the top cap portion 124 and the side cap portion 122 cooperate to define the transfer channel 120a. As an example, the top cap portion 124 may be formed in the shape of a substantially flat plate, and the top cap portion 124 may be provided so as to cooperate with the side cap portion 122 to form a substantially U-shaped cross section.

[0081] The gas diffusion layer 200 may be supported on the outer surface (top surface in FIG. 2 ) of the top cap portion 124, and the target fluid that has passed through the through-holes 112 may move along the internal space (movement flow path) of the top gap portion. The size of the top cap portion 124 may vary depending on required conditions and design specifications, and the present invention is not limited or restricted by the size of the top cap portion 124. Preferably, the top cap portion 124 may be formed to have a size (area in contact with the gas diffusion layer) that corresponds to 50% or more of the total area of ​​the through-holes 112.

[0082] According to another embodiment of the present invention, the top cap portion 124 may be formed to have a size that is less than 50% (e.g., 25%) of the total area of ​​the through hole 112. However, if the size of the top cap portion 124 is less than 50% of the total area of ​​the through hole 112, it is difficult to effectively support the sealing member 130 around the through hole 112 (prevent over-compression of the sealing member). Therefore, it is preferable that the top cap portion 124 be formed to have a size that corresponds to 50% or more of the total area of ​​the through hole 112.

[0083] The hole cap 120 can be provided in various ways depending on the required conditions and design specifications. According to a preferred embodiment of the present invention, the hole cap 120 may be integrally formed with the plate body 110 by partially processing (e.g., pressing) a part of the plate body 110.

[0084] Preferably, the hole caps 120 may be formed together with the channels (formed in a single process) when forming the channels by partially processing a portion of the plate body 110. In this manner, the embodiment of the present invention can obtain advantageous effects of simplifying the structure and manufacturing process and reducing costs by molding the hole caps 120 together when molding the separator 100 (e.g., the channel molding process).

[0085] 5 and 6, according to a preferred embodiment of the present invention, the fuel cell stack 10 may include side holes 126 formed through the wall surface of the side cap portion 122. The structure of the side holes 126 may be formed in various structures depending on required conditions and design specifications, and the structure of the side holes 126 does not limit or restrict the present invention.

[0086] For example, the side hole 126 may be formed in a substantially circular hole shape, or a plurality of side holes 126 may be provided spaced apart at predetermined intervals. Preferably, a plurality of side holes 126 may be formed in a first wall surface of the side cap portion 122 and a second wall surface of the side cap portion 122 opposite the first wall surface, respectively, spaced apart at predetermined intervals. According to other embodiments of the present invention, only one side hole may be formed in the wall surface of the side cap portion, or a long side hole having a substantially oblong shape may be formed.

[0087] With this structure, the target fluid that passes through the through hole 112 can be supplied to the flow path section 101 along the movement flow path 120a, and at the same time, can be bypassed via the side hole 126 and additionally supplied to the flow path section 101.

[0088] In this way, by providing the side hole 126 in the side cap portion, the embodiment of the present invention can ensure a smoother flow of the target fluid passing through the through hole 112, and can achieve the advantageous effect of reducing the generation of differential pressure in the through hole 112.

[0089] 7 to 9, according to a preferred embodiment of the present invention, the fuel cell stack 10 may include a reinforcing portion 140 that supports the hole cap 120 relative to the plate body 110. The reinforcing portion 140 is provided so that the hole cap 120 does not collapse and maintains its shape (ensuring a flow path for movement) when a fastening pressure is applied to the fuel cell stack 10.

[0090] The reinforcing portion 140 may be provided in various structures capable of supporting the hole cap 120 relative to the plate body 110, and the present invention is not limited or restricted by the structure of the reinforcing portion 140. As an example, the reinforcing portion 140 may be provided inside the through-hole 112. According to another embodiment of the present invention, the reinforcing portion may be provided outside the through-hole (e.g., on the outer surface of the side cap portion).

[0091] According to a preferred embodiment of the present invention, the reinforcing portion 140 may include a center reinforcing member 142 connected to the inner surface of the top cap portion 124, a first side reinforcing member 144 having one end connected to one side of the center reinforcing member 142 and the other end connected to the plate body 110, and a second side reinforcing member 146 having one end connected to the other side of the center reinforcing member 142 and the other end connected to the plate body 110.

[0092] The center reinforcing member 142 may be provided in various structures capable of supporting the inner surface of the top cap portion 124. As an example, the center reinforcing member 142 may be disposed in a substantially linear manner in the center of the inner surface of the top cap portion 124.

[0093] The first side reinforcing member 144 and the second side reinforcing member 146 are provided to support the center reinforcing member 142 relative to the plate body 110. Preferably, a plurality of the first side reinforcing members 144 and the second side reinforcing members 146 may be provided spaced apart along the length of the center reinforcing member 142, and the first side reinforcing members 144 and the second side reinforcing members 146 may be provided to cooperate with the center reinforcing member 142 to form an approximately fishbone shape.

[0094] As described above, the embodiment of the present invention provides a plurality of first side reinforcing members 144 and second side reinforcing members 146 spaced apart along the length of the center reinforcing member 142, thereby more stably supporting the center reinforcing member 142 and ensuring smooth flow of the target fluid.

[0095] Furthermore, according to a preferred embodiment of the present invention, the fuel cell stack 10 may include a center hole 142a formed in the center reinforcing member 142 so as to penetrate one side and the other side of the center reinforcing member 142. For example, the center reinforcing member 142 may have a plurality of center holes 142a formed therein, spaced apart at predetermined intervals. The number and spacing of the center holes 142a may vary depending on required conditions and design specifications.

[0096] In this way, the embodiment of the present invention has the advantageous effect of minimizing the reduction in the flow of the target fluid caused by providing the center reinforcing member 142 inside the hole cap 120 by forming the center hole 142a in the center reinforcing member 142.

[0097] As described above, the present invention provides an advantageous effect of ensuring smooth flow of reactant gases and coolant, thereby improving safety and reliability. In particular, the present invention provides an advantageous effect of ensuring stable flow of reactant gases and coolant through through-holes that guide the reactant gases and coolant that have flowed in through manifold channels of the separator to the reaction region, thereby improving flow efficiency.

[0098] In addition, according to an embodiment of the present invention, it is possible to obtain the advantageous effect of suppressing excessive compression (deformation) of the sealing member and stably securing the flow path area through which the reaction gas and cooling water that pass through the through-hole move.

[0099] Furthermore, according to the embodiment of the present invention, it is possible to obtain the advantageous effect of ensuring the airtightness (clamping pressure) of the fuel cell while ensuring the flow of reactant gases and coolant. Furthermore, according to the embodiment of the present invention, it is possible to obtain the advantageous effect of simplifying the structure and manufacturing process, thereby reducing manufacturing costs. Furthermore, according to the embodiment of the present invention, it is possible to obtain the advantageous effect of minimizing the distribution deviation (flow rate deviation) of reactant gases, thereby ensuring stable output performance.

[0100] The above description has focused on the embodiments, but these are merely examples and do not limit the present invention. Those skilled in the art will recognize that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the present invention. For example, each component specifically illustrated in the embodiments can be modified and implemented. Differences related to such modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims. [Explanation of symbols]

[0101] 10: Fuel cell stack 100: Separator 101: Flow path section 102: Manifold section 110: Plate body 112:Through hole 120: Hole cap 120a: moving channel 122: Side cap part 124: Top cap part 126: Side hole 130: Sealing material 132: Distribution channel 140: Reinforcement section 142: Center reinforcement member 142a: Center Hall 144: First side reinforcing member 146: Second side reinforcement member 200: Gas diffusion layer 300: Membrane electrode assembly

Claims

1. A fuel cell separator laminated on a gas diffusion layer provided in a membrane electrode assembly (MEA), a plate body including a flow path portion defining a reaction region that reacts with the membrane electrode assembly and a manifold portion spaced apart from the flow path portion, the plate body being laminated on the gas diffusion layer; a through hole formed in the plate body, the through hole guiding the target fluid that has passed through the manifold portion to the flow path portion; a hole cap provided on one surface of the plate body facing the gas diffusion layer to cover at least a portion of the through-hole, the hole cap defining a flow path through which the target fluid moves.

2. The hole cap is a side cap portion provided on an edge of the through hole; a top cap portion spaced apart from the plate body and supported by the side cap portion to cover the through hole, The fuel cell separator according to claim 1 , wherein the transfer channel is defined in a space between the top cap portion and the plate body.

3. The fuel cell separator according to claim 2 , wherein the side cap portion is formed continuously along the edge of the through-hole.

4. The fuel cell separator according to claim 2 , further comprising a side hole formed through a wall surface of the side cap portion.

5. The fuel cell separator according to claim 2 , further comprising a reinforcing portion that supports the hole cap relative to the plate body.

6. The fuel cell separator according to claim 5 , wherein the reinforcing portion is provided inside the through-hole.

7. The reinforcing portion is a center reinforcing member connected to the inner surface of the top cap portion; a first side reinforcing member having one end connected to one side of the center reinforcing member and the other end connected to the plate body; 6. The fuel cell separator according to claim 5, further comprising: a second side reinforcing member, one end of which is connected to the other side of the center reinforcing member and the other end of which is connected to the plate body.

8. 8. The fuel cell separator of claim 7, wherein the first side reinforcing member and the second side reinforcing member are provided in a plurality of pieces spaced apart from each other along the length of the center reinforcing member.

9. The fuel cell separator of claim 7 , further comprising a center hole formed in the center reinforcing member so as to penetrate one side and the other side of the center reinforcing member.

10. 2. The fuel cell separator of claim 1, wherein the migration channel is defined parallel to the plate body.

11. a sealing member provided on the plate body to seal the through-holes adjacent to each other, the sealing member defining a distribution channel connecting the flow path portion and the through-holes to communicate with each other; 2. The fuel cell separator of claim 1, wherein the hole cap is located inside the distribution channel.

12. 2. The fuel cell separator according to claim 1, wherein the hole cap is formed integrally with the plate body by partially processing a portion of the plate body.

13. a membrane electrode assembly (MEA); a gas diffusion layer laminated on the membrane electrode assembly; a separator including a plate body stacked on the gas diffusion layer, the plate body including a flow path portion defining a reaction region that reacts with the membrane electrode assembly and a manifold portion spaced apart from the flow path portion; through holes formed in the plate body and guiding a target fluid that has passed through the manifold portion to the reaction region; and hole caps disposed on one surface of the plate body facing the gas diffusion layer to cover at least a portion of the through holes and defining a movement flow path through which the target fluid moves.

14. The hole cap is a side cap portion provided on an edge of the through hole; a top cap portion spaced apart from the plate body and supported by the side cap portion to cover the through hole, The fuel cell stack of claim 13 , wherein the transfer channel is defined in a space between the top cap portion and the plate body.

15. The fuel cell stack according to claim 14 , further comprising a side hole formed through a wall surface of the side cap portion.

16. The fuel cell stack of claim 14 , further comprising a reinforcement portion for supporting the hole cap relative to the plate body.

17. The reinforcing portion is a center reinforcing member connected to the inner surface of the top cap portion; a first side reinforcing member having one end connected to one side of the center reinforcing member and the other end connected to the plate body; 17. The fuel cell stack of claim 16, further comprising: a second side reinforcing member, one end of which is connected to the other side of the center reinforcing member and the other end of which is connected to the plate body.

18. The fuel cell stack of claim 17 , further comprising a center hole formed in the center reinforcing member so as to penetrate one side and the other side of the center reinforcing member.

19. a sealing member provided on the plate body to seal the through-holes adjacent to each other, the sealing member defining a distribution channel connecting the flow path portion and the through-holes to communicate with each other; The fuel cell stack of claim 13 , wherein the hole cap is located inside the distribution channel.

20. The fuel cell stack according to claim 13 , wherein the hole cap is integrally formed with the plate body by partially processing a portion of the plate body.

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