Membranes and fuel cell stacks for fuel cells

Abstract

A membrane for a fuel cell is stacked on a reaction layer including a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA. The membrane includes: a plate stacked on the GDL; a stepped portion on which a reactant gas flows in a first direction, disposed on a first surface of the plate facing the GDL, the stepped portion being disposed in a second direction intersecting the first direction of reactant gas flow; bosses disposed on the stepped portion and spaced apart from each other in the second direction, the bosses contacting the GDL; a first channel defined between the GDL and the stepped portion and disposed between adjacent bosses, the first channel being configured to allow reactant gas to flow along the first channel; and a second channel defined between the plate and the GDL and communicating with the first channel, the second channel being configured to allow reactant gas to flow along the second channel.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Korean Patent Application 10-2021-0049858, filed with the Korean Intellectual Property Office on April 16, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a membrane for a fuel cell and a fuel cell stack, and more particularly to a fuel cell with higher performance and operating efficiency. Background Technology

[0004] A fuel cell stack is a power generation device that generates electricity through the chemical reaction of fuel (such as hydrogen). A fuel cell stack can be composed of dozens or hundreds of fuel cells (cells) stacked in series.

[0005] A fuel cell may include a membrane electrode assembly (MEA) having an electrolyte membrane that allows hydrogen cations to move through, and electrodes (catalyst electrode layers) disposed on two opposing surfaces of the electrolyte membrane to enable a reaction between hydrogen and oxygen. The fuel cell may also include a gas diffusion layer (GDL) configured to be in close contact with the two opposing surfaces of the MEA and to uniformly distribute the reactant gases and transfer the generated electrical energy; and a diaphragm (bipolar plate) in close contact with the gas diffusion layer to define the flow path.

[0006] The diaphragm may include an anode diaphragm for conveying hydrogen as fuel and a cathode diaphragm for conveying air as an oxidant. The diaphragm includes channels for the flow of fuel or oxidant and lands that are in contact with the gas diffusion layer and serve as electrical pathways.

[0007] Meanwhile, in order to maximize the performance of the fuel cell stack, it is necessary to increase the reaction area of ​​the reactant gas delivered to the gas diffusion layer and improve the delivery efficiency of the reactant gas.

[0008] In related technologies, in order to maximize the performance of fuel cell stacks, a method has been proposed to uniformly distribute the surface pressure of membrane electrode assembly by setting porous components, such as metal foam or wire mesh, on the membrane (e.g., cathode membrane) to improve the diffusion performance of reactant gases and the discharge performance of generated water.

[0009] However, in related technologies, a separate porous component needs to be placed between the gas diffusion layer and the membrane, which complicates the structure and manufacturing process of the membrane and increases its manufacturing cost.

[0010] In related technologies, the presence of porous components between the gas diffusion layer and the membrane makes it difficult to ensure sufficient contact area between them. This leads to increased resistance and consequently reduced output of the fuel cell stack. Furthermore, stress concentration caused by the porous components (i.e., stress concentration caused by the irregular cross-sectional shape of the porous components) during fuel cell stack fastening can also cause deformation and damage to the gas diffusion layer.

[0011] Therefore, recent studies have focused on simplifying membrane structures while simultaneously ensuring the reaction area and transport efficiency of the reactant gases, but the results remain insufficient. Thus, it is necessary to develop a technology that can simplify membrane structures while simultaneously ensuring the reaction area and transport efficiency of the reactant gases. Summary of the Invention

[0012] This disclosure aims to provide a membrane for a fuel cell and a fuel cell stack that can improve performance and operating efficiency.

[0013] This disclosure also aims to ensure the reaction area of ​​the reactant gas delivered to the gas diffusion layer without using porous components, and to improve the delivery efficiency of the reactant gas.

[0014] This disclosure also aims to ensure that the reactant gas flows in the thickness direction of the membrane (from the membrane toward the gas diffusion layer), and at the same time ensures that the reactant gas flows in the plane directions (first direction and second direction) that intersect with each other on the membrane.

[0015] This disclosure also aims to simplify the structure and manufacturing process of the diaphragm, thereby reducing its manufacturing cost.

[0016] This disclosure also aims to reduce the contact impedance (resistance) between the gas diffusion layer and the membrane, thereby improving the output of the fuel cell stack.

[0017] This disclosure also aims to minimize deformation and damage to the gas diffusion layer and improve its durability.

[0018] This disclosure also aims to improve stability and reliability.

[0019] The objectives that can be achieved by the embodiments are not limited to those mentioned above, but also include objectives or effects that can be understood from the schemes or embodiments described below.

[0020] On one hand, this disclosure provides a membrane for a fuel cell, stacked on a reaction layer including a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA. The membrane includes: a plate stacked on the GDL; a stepped portion on which a reactant gas flows in a first direction, the stepped portion being disposed on a first surface of the plate facing the GDL, and the stepped portion being disposed in a second direction intersecting the first direction of the reactant gas flow; bosses disposed on the stepped portion and spaced apart from each other in the second direction, the bosses contacting the GDL; a first channel for the flow of reactant gas extending between the GDL and the stepped portion, disposed between adjacent bosses; and a second channel for the flow of reactant gas extending between the plate and the GDL and communicating with the first channel.

[0021] This design aims to improve the performance and operating efficiency of fuel cells.

[0022] In other words, to optimize the performance of the fuel cell stack, it is necessary to increase the reaction area of ​​the reactant gas delivered to the GDL and improve the delivery efficiency of the reactant gas.

[0023] However, in related technologies, separate porous components need to be placed between the GDL and the diaphragm, which complicates the structure and manufacturing process of the diaphragm and increases its manufacturing cost.

[0024] In related technologies, due to the presence of porous components between the fuel cell stack (GDL) and the membrane, it is difficult to ensure sufficient contact area between them. This leads to increased resistance and consequently reduced output of the fuel cell stack. Furthermore, during the fastening of the fuel cell stack, the GDL may deform and be damaged due to stress concentration caused by the porous components (i.e., stress concentration caused by the irregular cross-sectional shape of the porous components).

[0025] In contrast, in embodiments of this disclosure, the stepped portion may be positioned in a second direction intersecting the first direction of the reactant gas flow, and the reactant gas may flow along a first channel defined between the GDL and the stepped portion and located between the bosses. Therefore, the beneficial effects of ensuring the reaction area of ​​the reactant gas delivered to the GDL and improving the delivery efficiency of the reactant gas can be achieved without providing additional porous components.

[0026] Furthermore, in the embodiments of this disclosure, when the reactant gas flows through the stepped portion, the flow of the reactant gas can be confined along the thickness direction of the diaphragm (from the diaphragm toward the GDL). Therefore, it is possible to obtain the beneficial effect of further improving the material delivery performance (reactant gas delivery performance) to the GDL.

[0027] Furthermore, in the embodiments of this disclosure, since porous components are not included and the membrane is in direct contact with the GDL, the contact impedance (resistance) between the GDL and the membrane can be reduced and stress concentration minimized. Therefore, the beneficial effects of minimizing deformation and damage to the GDL and improving durability during fuel cell stack fastening can be achieved.

[0028] Furthermore, in embodiments of this disclosure, since porous components may not be included, the welding process for attaching porous components to the diaphragm can be eliminated. Therefore, the beneficial effects of simplifying the diaphragm structure and the diaphragm manufacturing process can be achieved.

[0029] The steps can be designed in various ways depending on the requirements and design specifications. In particular, the steps can be created as an embossed feature on one surface of the panel by partially machining a portion of the panel.

[0030] Bosses can be set up in a variety of ways depending on the required conditions and design specifications. In particular, a boss can be set as an relief on one surface of a stepped portion by partially machining a part of the plate.

[0031] Since bosses can be set by partially machining a portion of the plate as described above, the beneficial effects of reducing costs and simplifying the boss manufacturing process can be achieved.

[0032] According to exemplary embodiments of the present disclosure, the boss may have a polygonal cross-sectional shape or a circular cross-sectional shape.

[0033] According to an exemplary embodiment of this disclosure, the boss can be configured in the form of a grid.

[0034] Because the multiple bosses are arranged in a regular grid pattern as described above, stress concentration at specific locations on the GDL can be minimized when the fuel cell stack is fastened. Therefore, the beneficial effect of minimizing deformation and damage to the GDL caused by stress concentration can be achieved.

[0035] According to an exemplary embodiment of this disclosure, the boss may be disposed in different rows in a first direction.

[0036] According to an exemplary embodiment of this disclosure, the first direction and the second direction may be defined as perpendicular (orthogonal) to each other.

[0037] According to an exemplary embodiment of this disclosure, the second channel can be continuously arranged in a second direction.

[0038] Specifically, the steps and the second passage can be alternated in the first direction.

[0039] According to an exemplary embodiment of the present disclosure, the diaphragm for a fuel cell may include cooling channels disposed on another surface of the plate and configured to allow coolant to flow along the cooling channels.

[0040] Depending on the required conditions and design specifications, cooling channels can have various structures. In particular, cooling channels can be continuously arranged along the internal space of the stepped section.

[0041] Since the stepped portion and cooling channels are arranged on the plate as described above, the beneficial effects of simplifying the diaphragm structure and diaphragm manufacturing process can be achieved.

[0042] According to an exemplary embodiment of the present disclosure, at least two plates may be configured to be in close contact with each other, and cooling channels respectively provided on the plates may be interconnected to define a common cooling channel.

[0043] Since the two cooling channels are interconnected as described above, a straight common cooling channel with a further enlarged cross-sectional area can be provided, thereby improving the flow of the coolant. Therefore, the beneficial effect of maximizing the cooling performance and efficiency achieved by the coolant can be obtained.

[0044] According to an exemplary embodiment of the present disclosure, the diaphragm for a fuel cell may include an inclined guide portion disposed on a boss and configured to guide the reactant gas toward the GDL.

[0045] Since the inclined guide portion is provided on the boss as described above, the movement direction of the reactant gas moving towards the sidewall of the boss can be changed to the thickness direction of the diaphragm of the inclined guide portion (from the diaphragm towards the GDL). Therefore, the inclined guide portion can impart a velocity component to the reactant gas moving towards the GDL and guide the reactant gas towards the GDL. Thus, the beneficial effect of further improving the delivery efficiency of the reactant gas to the GDL can be obtained.

[0046] According to an exemplary embodiment of the present disclosure, the diaphragm for a fuel cell may include a circular portion disposed at the boundary between the inclined guide portion and the boss surface of the boss.

[0047] Because the circular portion is positioned at the boundary between the boss surface and the inclined guide portion as described above, the reactant gas guided to the GDL along the inclined guide portion can flow more smoothly and gently. Therefore, the repulsive force induced by the inclined guide portion can be minimized, and the delivery efficiency of the reactant gas to the GDL can be further improved.

[0048] Furthermore, since the circular portion is positioned at the boundary between the boss surface and the inclined guide portion, stress concentration in the edge region of the boss surface can be suppressed during the fastening of the fuel cell stack. Therefore, the beneficial effect of minimizing deformation and damage to the GDL caused by stress concentration can be achieved.

[0049] On the other hand, this disclosure provides a fuel cell stack comprising: a reaction layer including a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA; a plate stacked on the GDL; a stepped portion on which reactant gas flows in a first direction, disposed on a first surface of the plate, the first surface facing the GDL, the stepped portion being disposed in a second direction intersecting the first direction of reactant gas flow; bosses disposed on the stepped portion and spaced apart from each other in the second direction, the bosses contacting the GDL; a first channel for reactant gas flow extending between the GDL and the stepped portion and disposed between adjacent bosses; and a second channel for reactant gas flow extending between the plate and the GDL and communicating with the first channel.

[0050] According to the above embodiments of this disclosure, beneficial effects such as improved performance and operating efficiency can be obtained.

[0051] In particular, according to embodiments of this disclosure, it is possible to obtain the beneficial effects of ensuring the reaction area of ​​the reactant gas delivered to the GDL without providing porous components, and improving the delivery efficiency of the reactant gas.

[0052] Furthermore, according to embodiments of this disclosure, it is possible to obtain the beneficial effect of ensuring the flow of the reactant gas in the thickness direction of the membrane (from the membrane toward the GDL) and simultaneously ensuring the flow of the reactant gas in the intersecting planar directions (first direction and second direction) on the membrane. Moreover, it is possible to obtain the beneficial effect of further improving the material delivery performance (reactant gas delivery performance) to the GDL.

[0053] Furthermore, according to embodiments of this disclosure, beneficial effects such as reducing the contact impedance (resistance) between the GDL and the membrane and improving the output of the fuel cell stack can be achieved.

[0054] Furthermore, according to embodiments of this disclosure, beneficial effects such as simplified structure and manufacturing process and reduced manufacturing costs can be achieved.

[0055] Furthermore, according to exemplary embodiments of this disclosure, the beneficial effects of minimizing GDL deformation and damage and improving durability can be achieved.

[0056] Furthermore, according to the embodiments of this disclosure, beneficial effects such as improved stability and reliability can be obtained. Attached Figure Description

[0057] Figure 1 A view illustrating a fuel cell stack according to an embodiment of the present disclosure;

[0058] Figure 2 and Figure 3 A view illustrating a diaphragm for a fuel cell according to an embodiment of the present disclosure;

[0059] Figure 4 A view illustrating the cooling channel of the diaphragm for a fuel cell according to an embodiment of the present disclosure;

[0060] Figure 5 A view illustrating the flow of reactant gases in a membrane for a fuel cell according to an embodiment of the present disclosure;

[0061] Figure 6 and Figure 7 A view illustrating the tilted guide portion of the diaphragm for a fuel cell according to an embodiment of the present disclosure;

[0062] Figure 8 and Figure 9 A view illustrating an improved example of a boss in a diaphragm for a fuel cell according to an embodiment of the present disclosure. Detailed Implementation

[0063] The embodiments of this disclosure are described in detail below with reference to the accompanying drawings.

[0064] However, the technical spirit of this disclosure is not limited to the embodiments described herein, but can be implemented in various different forms. Within the scope of the technical spirit of this disclosure, one or more components in the embodiments can be selectively combined and substituted.

[0065] Furthermore, unless otherwise specifically defined and stated, the terms (including technical and scientific terms) used in the embodiments of this disclosure are to be understood as having the meaning commonly understood by one of ordinary skill in the art to which this disclosure pertains. The meaning of commonly used terms, such as the meaning of terms as defined in a dictionary, can be interpreted taking into account the contextual meaning of related technologies.

[0066] Furthermore, the terminology used in the embodiments of this disclosure is for the purpose of describing the embodiments and is not intended to limit the disclosure.

[0067] In this specification, unless otherwise specified, the singular form may also include the plural form. The expression "at least one (or one or more) of A, B, and C" may include one or more of all combinations formed by combining A, B, and C.

[0068] Additionally, terms such as first, second, A, B, (a), and (b) may be used to describe the constituent elements of embodiments of this disclosure.

[0069] These terms are used only to distinguish one component from another; the nature, sequence, or order of the components are not limited by these terms.

[0070] Furthermore, when a component is described as “connected,” “coupled,” or “attached” to another component, a component may be directly connected, coupled, or attached to another component, or may be connected, coupled, or attached to another component through another component inserted between them.

[0071] Furthermore, the expression "one component is formed or disposed on (above) or below (below) another component" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or disposed between the two components. The expression "on (above) or below (below)" can include meanings based on the downward direction and the upward direction of a component.

[0072] Reference Figures 1 to 9 According to an embodiment of the present disclosure, a fuel cell stack 10 includes: a reaction layer 100 including a membrane electrode assembly (MEA) 110 and a gas diffusion layer (GDL) 120 stacked on the MEA 110; a plate 210 stacked on the GDL 120; a stepped portion 220 disposed on a surface of each plate 210 facing the GDL 120 and disposed in a second direction D2 intersecting a first direction D1 for supplying reactant gases; bosses 230 disposed on the stepped portions 220 and spaced apart from each other in the second direction D2, and contacting each GDL 120; a first channel 240 located between each GDL 120 and the stepped portion 220 and between adjacent bosses 230, and configured to allow reactant gases to flow therein; and a second channel 250 located between the plate 210 and the GDL 120 and communicating with the first channel 240, and configured to allow reactant gases to flow therein.

[0073] For reference, the fuel cell stack 10 can be positioned in a reference direction (e.g., based on...) Figure 1 It is constructed by stacking multiple cell units in the upward / downward direction.

[0074] A fuel cell (unit cell) may include a reaction layer 100 and a membrane 200 stacked on two opposite surfaces of the reaction layer 100. A fuel cell stack 10 may be constructed by stacking multiple fuel cells in a reference direction and then assembling end plates (not shown) at two opposite ends of the multiple fuel cells.

[0075] More specifically, the reaction layer 100 includes a membrane electrode assembly (MEA) 110, which is configured such that a catalyst electrode layer in which an electrochemical reaction occurs is attached to two opposite sides of an electrolyte membrane in which hydrogen ions move. The reaction layer 100 also includes a gas diffusion layer (GDL) 120 in close contact with the two opposite sides of the membrane electrode assembly 110 and configured to uniformly distribute the reactant gases and transfer the generated electrical energy.

[0076] The membrane electrode assembly 110 is used to generate electricity through a redox reaction between a fuel (e.g., hydrogen) as a first reactant gas and an oxidant (e.g., air) as a second reactant gas.

[0077] The structure and materials of the membrane electrode assembly 110 can be varied according to the required conditions and design specifications, and this disclosure is not limited or restricted by the structure and materials of the membrane electrode assembly 110.

[0078] For example, the membrane electrode assembly 110 includes an electrolyte membrane through which hydrogen ions move, and a catalyst electrode layer attached to two opposite surfaces of the electrolyte membrane, in which an electrochemical reaction occurs.

[0079] A gas diffusion layer (GDL) 120 is stacked on two opposite surfaces of the membrane electrode assembly 110 and is used to uniformly distribute the reactant gas and transfer the generated electrical energy.

[0080] GDL 120 can have various structures capable of diffusing reactive gases. For example, GDL 120 can have a porous structure with pores, each pore having a predetermined size.

[0081] The hole size and material of GDL 120 can be varied according to required conditions and design specifications, and this disclosure is not limited or constrained by the hole size and material of GDL 120.

[0082] The diaphragm 200 is used not only to block (separate) hydrogen and air as reactant gases, but also to ensure the flow path of the reactant gases and to transmit current to the external circuit.

[0083] In addition, the diaphragm 200 can also be used to distribute the heat generated in the fuel cell (cell) throughout the fuel cell, and the excess heat can be discharged to the outside by the coolant flowing between the diaphragms 200 along the cooling channel 260.

[0084] In embodiments of this disclosure, the diaphragm 200 may be defined as including an anode diaphragm 200 and a cathode diaphragm 200, the anode diaphragm 200 being configured to define a flow path for hydrogen as fuel, and the cathode diaphragm 200 being configured to define a flow path for air as an oxidant.

[0085] For example, the membrane 200 may be made of a thin-film metallic material (e.g., stainless steel, Inconel, or aluminum). The membrane 200 (anode and cathode membranes) together with the reaction layer 100 can constitute a single fuel cell (cell) and independently define the flow paths for hydrogen, air, and coolant. According to another embodiment of this disclosure, the membrane may be made of another material, such as graphite or a carbon composite material.

[0086] For reference, hydrogen as fuel and air as oxidant are supplied to the anode (not shown) and cathode (not shown) of the membrane electrode assembly 110 through channels 240 and 250 in the diaphragm 200 (cathode diaphragm and anode diaphragm), respectively. Hydrogen can be supplied to the anode and air can be supplied to the cathode.

[0087] Hydrogen gas supplied to the anode is separated into hydrogen ions (protons) and electrons by catalysts in electrode layers located on two opposite sides of the electrolyte membrane. Only hydrogen ions are selectively transported to the cathode through the electrolyte membrane, which serves as a cation exchange membrane, while electrons are transported to the cathode through GDL 120 and membrane 200—both of which are conductors.

[0088] At the cathode, hydrogen ions transported through the electrolyte membrane and electrons transported through the diaphragm 200 meet with oxygen from the air supplied to the cathode via the air supply device, resulting in a reaction that produces water. Due to the movement of hydrogen ions, electrons flow through the external wires, and this flow of electrons generates an electric current.

[0089] For example, refer to Figure 1 A diaphragm 200 for conveying hydrogen (e.g., an anode diaphragm) may be disposed on the upper surface of the membrane electrode assembly 110, and a diaphragm 200 for conveying air (e.g., a cathode diaphragm) may be disposed on the lower surface of the membrane electrode assembly 110.

[0090] More specifically, the diaphragm 200 includes: a plate 210 stacked on one surface of each GDL 120, the GDL 120 stacked on the membrane electrode assembly 110; a stepped portion 220 disposed on one surface of the plate 210 facing the GDL 120 and disposed in a second direction D2 intersecting a first direction D1 for conveying the reactant gas; bosses 230 disposed on the stepped portion 220 to be spaced apart from each other in the second direction D2 and in contact with each GDL 120; a first channel 240 defined between each GDL 120 and the stepped portion 220 and located between adjacent bosses 230 and configured to allow the reactant gas to flow therein; and a second channel 250 located between the plate 210 and each GDL 120 and communicating with the first channel 240 and configured to allow the reactant gas to flow therein.

[0091] Reference Figures 1 to 5 The plate 210 may be provided in the form of a flat film plate, and this disclosure is not limited or constrained by the size, material and structure of the plate 210.

[0092] For example, plate 210 may be provided in the form of a flat quadrilateral plate and made of typical metallic materials such as stainless steel, chromium-nickel-iron alloy or aluminum.

[0093] The stepped portion 220 protrudes from one surface of the plate 210 facing GDL 120 and is positioned in the first direction D1 (e.g., based on) the direction of transporting the reaction gas. Figure 1 The second direction D2 intersects with the left / right direction.

[0094] For reference, in this embodiment of the disclosure, the first direction D1 may be defined as the direction in which the reactant gas is transported from one end of the diaphragm 200 to the interior of the diaphragm 200 (or the other end of the diaphragm 200).

[0095] Furthermore, the second direction D2 can be defined as any direction that intersects the first direction D1 in the same plane. In particular, the first direction D1 and the second direction D2 can be defined as perpendicular (orthogonal) to each other.

[0096] The height (height in the diaphragm thickness direction) and width (width in the first direction) of the step portion 220 can be varied according to the required conditions and design specifications, and this disclosure is not limited or constrained by the height and width of the step portion 220.

[0097] For reference, as the height of the step portion 220 increases, the concentration of the reactant gas acting on the GDL 120 while flowing through the step portion 220 increases. For example, when the height of the step portion 220 increases by 0.1 mm, the concentration of the reactant gas acting on the GDL 120 can increase by approximately 65%.

[0098] Specifically, the step portion 220 can be configured as a plurality of steps, and the plurality of step portions 220 can be spaced apart from each other at a predetermined interval in the first direction D1.

[0099] The step portion 220 can be provided in a variety of ways depending on the required conditions and design specifications. In particular, the step portion 220 can be integrated with the plate 210 by partially processing (e.g., pressing) a portion of the plate 210.

[0100] More specifically, by partially machining a portion of the plate 210, the stepped portion 220 can be configured as an relief on one surface of the plate 210. Furthermore, the stepped portion 220 can have the same thickness as the plate 210.

[0101] Since the step portion 220 is provided by partially machining a portion of the plate 210 as described above, the beneficial effects of reducing costs and simplifying the manufacturing process of the step portion 220 can be achieved.

[0102] According to another embodiment of this disclosure, the stepped portion can be formed on the plate by die casting or cutting. Alternatively, the stepped portion can be manufactured separately from the plate and then attached or coupled to the plate.

[0103] The boss 230 is provided on the outer surface of the step portion 220 and is spaced apart from each other in the second direction D2. The boss surface 230a of the boss 230 can contact the GDL 120.

[0104] The boss 230 can have various structures that can contact the GDL 120, and this disclosure is not limited or restricted by the shape and structure of the boss 230. In addition, the spacing between the bosses 230 and the number of bosses 230 can also be varied according to the required conditions and design specifications.

[0105] For example, the boss 230 may have an approximately quadrilateral block shape and protrude from the outer surface of the step portion 220. The bosses 230 may be arranged to be spaced apart from each other at a predetermined distance in the second direction D2.

[0106] The first width (width in the first direction), the second width (width in the second direction), and the height (height in the diaphragm thickness direction) of the boss 230 can be varied according to the required conditions and design specifications, and this disclosure is not limited or constrained by the height and width (first width and second width) of the boss 230.

[0107] In particular, the multiple protrusions 230 provided on the step portion 220 can be arranged in a regular grid pattern.

[0108] In this case, the multiple bosses 230 are arranged in a regular grid pattern. This can be understood as the following: the multiple bosses 230 are arranged in the same row in the first direction D1, and even in the same row in the second direction D2.

[0109] Since the multiple bosses 230 are arranged in a regular grid pattern as described above, stress concentration at specific locations on the GDL 120 can be minimized when the fuel cell stack 10 is fastened. Therefore, the beneficial effect of minimizing deformation and damage to the GDL 120 caused by stress concentration can be achieved.

[0110] The boss 230 can be provided in various ways depending on the required conditions and design specifications. In particular, the boss 230 can be integrally provided with the plate 210 by partially machining (e.g., pressing) a portion of the plate. In particular, the step portion 220 and the boss 230 can be provided together in a single process.

[0111] Similar to the step portion 220, the boss 230 can be formed as an embossed feature on one surface (the surface facing the GDL) of the step portion 220 by partially machining a portion of the plate body 210. The boss 230 can have the same thickness as the step portion 220 and the plate body 210.

[0112] Since the boss 230 is provided by partially machining a portion of the plate 210, the beneficial effects of reducing costs and simplifying the manufacturing process of the boss 230 can be achieved.

[0113] According to another embodiment of this disclosure, the boss can be provided on the stepped portion by die casting or machining. Alternatively, the boss can be manufactured separately from the plate and then attached or coupled to the plate.

[0114] The first channel 240 is defined between GDL 120 and the step portion 220 and is disposed between adjacent bosses 230, and the reaction gas delivered to the diaphragm 200 can flow along the first channel 240 in the first direction D1.

[0115] As described above, in the embodiments of this disclosure, since the reactant gas supplied to the diaphragm 200 flows along the first channel 240, the flow of the reactant gas in the planar direction (e.g., the first direction) of the diaphragm 200 can be guaranteed, and the flow of the reactant gas in the thickness direction of the diaphragm 200 (e.g., from the diaphragm towards the GDL, see...) can also be guaranteed. Figure 1 The flow on D3 (defined in the text) defines the three-dimensional flow of the reactant gas. Therefore, beneficial effects can be obtained by improving the mass transport performance (reactant gas transport performance) up to GDL 120.

[0116] Specifically, in embodiments of this disclosure, when the reactant gas flows through the step portion 220, the flow GF1 of the reactant gas is confined in the direction from the diaphragm 200 toward the GDL 120. Therefore, a further improvement in the reactant gas delivery performance to the GDL 120 can be achieved.

[0117] The second channel 250 is defined between the plate 210 and the GDL 120, communicates with the first channel 240, and the reaction gas delivered to the diaphragm 200 (the reaction gas through the first channel) can flow along the second channel 250 in the second direction D2.

[0118] In this case, the second channel 250 can be understood as the space between the stepped portions 220 spaced apart from each other in the first direction D1.

[0119] Specifically, the second channel 250 is continuously and uninterruptedly set in the second direction D2.

[0120] More specifically, the step portion 220 and the second channel 250 are alternately arranged in the first direction D1.

[0121] The reactant gas that has passed through the first channel 240 can diffuse in the second direction D2 as it flows along the second channel 250, and the reactant gas flowing along the second channel 250 can flow through multiple first channels 240 again, so that the reactant gas can diffuse evenly throughout the entire area of ​​the diaphragm 200.

[0122] As described above, in the embodiments of this disclosure, since the reactant gas that has passed through the first channel 240 is GF2 diffused in the second direction D2 as it flows along the second channel 250, three-dimensional flow of the reactant gas GF1 and GF2 in the planar directions (e.g., the first and second directions) of the diaphragm 200 can be achieved. Therefore, the beneficial effects of further increasing the reaction area of ​​the reactant gas delivered to the GDL 120 and improving the delivery efficiency of the reactant gas can be obtained.

[0123] Furthermore, in embodiments of this disclosure, since the first channel 240 and the second channel 250 are disposed between the GDL 120 and the plate 210, the flow of the reactant gas in the planar direction (e.g., the first direction and the second direction) of the diaphragm 200 can be guaranteed (see...). Figure 5 (GF1 and GF2 in the membrane), and ensure that the reactant gas flows in the thickness direction of the membrane 200 (from the membrane 200 towards GDL 120, see...) Figure 1 The flow occurs on D3 (in the structure). Therefore, three-dimensional flow of the reactant gas can be achieved. Thus, it is possible to obtain the beneficial effect of improving the mass transport performance (reactant gas transport performance) to GDL 120 without using porous components.

[0124] Reference Figures 1 to 4 According to an exemplary embodiment of the present disclosure, the diaphragm 200 for a fuel cell may include cooling channels 260 disposed on another surface of the plate 210 and configured to allow coolant W to flow through them.

[0125] The cooling channel 260 can have various structures depending on the required conditions and design specifications, and this disclosure is not limited or restricted by the cooling channel 260.

[0126] Specifically, the cooling channel 260 can be continuously arranged along the internal space of the stepped portion 220 (and the boss).

[0127] In this case, the cooling channel 260 is defined as the internal space of the stepped portion 220. This can be understood as a configuration whereby when the stepped portion 220 is provided on the plate 210, the cooling channel 260 is configured as a space (recessed space) in the stepped portion 220.

[0128] Since the stepped portion 220 (with the boss) and the cooling channel 260 are provided on the plate 210 as described above, the beneficial effects of simplifying the structure of the diaphragm 200 and the manufacturing process of the diaphragm 200 can be obtained.

[0129] Specifically, at least two plates 210 are configured to be in close contact with each other, and cooling channels 260 provided on the plates 210 are respectively connected to each other, thereby defining a common cooling channel 260'.

[0130] That is, at least two plates 210 can be in close contact with each other (the plates are in close contact with each other such that the other surface of one plate faces the other surface of the other plate) in order to define different fuel cells (cell cells). Cooling channels 260 provided on the plates 210 are interconnected, thereby defining a common cooling channel 260'.

[0131] Since the two cooling channels 260 are interconnected as described above, a straight common cooling channel 260' with a further enlarged cross-sectional area (e.g., twice the cross-sectional area of ​​the cooling channels) can be provided, thereby improving the flow of the coolant. Therefore, the beneficial effect of maximizing the cooling performance and efficiency achieved by the coolant can be obtained.

[0132] Reference Figure 6 and Figure 7 According to an exemplary embodiment of the present disclosure, the diaphragm 200 for a fuel cell may include an inclined guide portion 270 disposed on a boss 230 and used to guide the reactant gas toward the GDL 120.

[0133] For example, the inclined guide portion 270 may be provided at the edge portion of the boss surface 230a to define the sidewall of the boss 230. In particular, the inclined guide portion 270 may be provided along the entire periphery of the boss 230. According to another embodiment of the present disclosure, the inclined guide portion may be provided only partially in a portion of the entire periphery of the boss.

[0134] The tilt angle of the inclined guide portion 270 (the tilt angle relative to the outer surface of the step portion) can be varied according to the required conditions and design specifications, and this disclosure is not limited or constrained by the tilt angle of the inclined guide portion 270.

[0135] For reference, in the embodiments of this disclosure, the inclined guide portion is illustrated as having a straight shape. However, according to another embodiment of this disclosure, the inclined guide portion may have a curved shape (e.g., an arc) or a combination of a straight shape and a curved shape.

[0136] Since the inclined guide portion 270 is provided on the boss 230 as described above, the movement direction of the reactant gas moving toward the sidewall of the boss 230 can be changed to the thickness direction of the diaphragm 200 of the inclined guide portion 270 (direction D3 from the diaphragm toward the GDL). Therefore, the inclined guide portion can impart a velocity component to the reactant gas moving toward the GDL 120 and guide the reactant gas to flow toward the GDL 120. Thus, the beneficial effect of further improving the delivery efficiency of the reactant gas to the GDL 120 can be obtained.

[0137] Reference Figure 7 and Figure 8 According to an exemplary embodiment of the present disclosure, the diaphragm 200 for a fuel cell may include a circular portion 280 disposed at the boundary between the inclined guide portion 270 and the boss surface 230a of the boss 230, the boss surface 230a being in contact with the GDL 120.

[0138] Since the circular portion 280 is disposed at the boundary between the boss surface 230a and the inclined guide portion 270 as described above, the reactant gas guided to the GDL 120 along the inclined guide portion can flow more smoothly and gently. Therefore, the repulsive force caused by the inclined guide portion can be minimized, and the delivery efficiency of the reactant gas to the GDL 120 can be further improved.

[0139] Furthermore, since the circular portion 280 is located at the boundary between the boss surface 230a and the inclined guide portion 270, stress concentration in the edge region of the boss surface 230a can be suppressed when the fuel cell stack 10 is fastened. Therefore, the beneficial effect of minimizing deformation and damage to the GDL 120 caused by stress concentration can be achieved.

[0140] Furthermore, in the embodiments of this disclosure illustrated and described above, a boss 230 in the form of a quadrilateral block with a quadrilateral cross-section is used as an example. However, according to another embodiment of this disclosure, the boss may have other cross-sectional shapes.

[0141] Reference Figure 8 According to an exemplary embodiment of the present disclosure, the boss 230 may have a circular cross-sectional shape.

[0142] In particular, the boss 230 may have a cross-sectional area that gradually decreases from one end adjacent to the terminal to the other end adjacent to the GDL 120.

[0143] For example, the boss 230 can be an approximately truncated cone shape (circular truncated cone shape) with a circular cross-section that gradually decreases from one end (the end adjacent to the terminal) to the other end. Alternatively, the boss 230 can be a truncated pyramid shape (flat truncated pyramid) with a polygonal cross-section that gradually decreases from one end (the end adjacent to the terminal) to the other end.

[0144] Since the cross-sectional area of ​​the boss 230 gradually decreases from one end (the end adjacent to the terminal) to the other end as described above, the inclined guide portion 270 can be provided on the side wall of the boss 230. In particular, the circular portion 280 can be provided at the boundary between the boss surface 230a and the inclined guide portion 270.

[0145] Furthermore, in the embodiments of this disclosure illustrated and described above, the example is given by having a plurality of protrusions 230 on the diaphragm 200 arranged in the same row in the first direction D1. However, according to another embodiment of this disclosure, the plurality of protrusions may be arranged in different rows in the first direction.

[0146] Reference Figure 9 According to an exemplary embodiment of the present disclosure, a plurality of protrusions 230 on the diaphragm 200 may be disposed in different rows in the first direction D1.

[0147] For example, at least one of the plurality of protrusions 230 disposed on the diaphragm 200 may be disposed on the first row C1 along the first direction D1, and another of the plurality of protrusions 230 disposed on the diaphragm 200 may be disposed on the second row C2 spaced apart from the first row C1 along the first direction D1. Therefore, the protrusions 230 and the first channel 240 may be alternately disposed on the first direction D1, and the second channel 250 is inserted between them.

[0148] Although embodiments have been described above, these embodiments are merely illustrative and not intended to limit the scope of this disclosure. Those skilled in the art will understand that various modifications and applications not described above can be made to these embodiments without departing from their essential characteristics. For example, modifications can be made to the various components specifically described in the embodiments before implementation. Furthermore, it should be understood that differences related to the modifications and applications described above are included within the scope of this disclosure as defined by the appended claims.

Claims

1. A membrane for a fuel cell, stacked on a reaction layer, the reaction layer comprising a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA, the membrane comprising: Plates, which are stacked on the GDL; The step portion is on which the reactant gas flows in a first direction. The step portion is disposed on a first surface of the plate, the first surface facing the GDL, and the step portion is disposed in a second direction intersecting the first direction of the reactant gas flow. A boss is provided on the stepped portion and spaced apart from each other in the second direction. The boss is in contact with the GDL. Each boss has a frustoconical shape with a circular cross-section that gradually decreases from one end of each boss to the other end of each boss. The one end of each boss is adjacent to one of the stepped portions and the other end is adjacent to the GDL. The first channel, through which the reactant gas flows, extends between the GDL and the stepped portion and is disposed between adjacent bosses in each of the bosses; and The second channel, through which the reactant gas flows, extends between the plate and the GDL and communicates with the first channel.

2. The diaphragm according to claim 1, wherein, The second channel extends continuously in the second direction.

3. The diaphragm according to claim 1, wherein, The stepped portion and the second channel are alternately arranged in the first direction.

4. The diaphragm according to claim 3, wherein, The bosses are arranged in the same row in the first direction.

5. The diaphragm according to claim 3, wherein, The bosses are arranged alternately in a serrated shape along the first direction.

6. The diaphragm according to claim 3, wherein, The protrusions are arranged in a grid pattern.

7. The diaphragm according to claim 1, wherein, The first direction and the second direction are orthogonal to each other.

8. The diaphragm according to claim 1, wherein, The stepped portion is disposed on the first surface of the plate, and each stepped portion is configured as an relief on a part of the plate.

9. The diaphragm according to claim 8, comprising a cooling channel through which coolant flows, the cooling channel being disposed on the second surface of the plate.

10. The diaphragm according to claim 9, wherein, The cooling channel extends along the interior space of the stepped portion.

11. The diaphragm according to claim 10, wherein, When there are multiple plates, at least two of the plates are arranged adjacent to each other, and the cooling channels on the at least two plates are interconnected as a common cooling channel.

12. The diaphragm according to claim 1, wherein, Each of the bosses is configured as an embossing on one surface of each of the stepped portions on a portion of the plate, the one surface facing the GDL.

13. The diaphragm according to claim 1, comprising an inclined guide portion disposed on each of the protrusions, the inclined guide portion being configured to guide the flow of the reactive gas toward the GDL.

14. The diaphragm of claim 13, comprising a circular portion disposed at the boundary between the inclined guide portion and the boss surface of each of the bosses, the boss surface being in contact with the GDL.

15. A fuel cell stack, comprising: The reaction layer includes a membrane electrode assembly (MEA) and a gas diffusion layer (GDL) stacked on the MEA. Plates, which are stacked on the GDL; The stepped portion, on which the reactant gas flows in a first direction, is disposed on the surface of the plate, the surface facing the GDL, and the stepped portion is disposed in a second direction intersecting the first direction of the reactant gas flow; A boss is provided on the stepped portion and spaced apart from each other in the second direction. The boss is in contact with the GDL. Each boss has a frustoconical shape with a circular cross-section that gradually decreases from one end of each boss to the other end of each boss. The one end of each boss is adjacent to one of the stepped portions and the other end is adjacent to the GDL. The first channel, through which the reactant gas flows, extends between the GDL and the stepped portion and is disposed between adjacent bosses in each of the bosses; and The second channel, through which the reactant gas flows, extends between the plate and the GDL and communicates with the first channel.

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