FUEL CELL

Abstract

Fuel cell, comprising: a catalyst layer (100) wherein hydrogen gas or air is introduced therethrough through a first surface and a second surface thereof; a first separator (200) disposed on a first side of the catalyst layer (100) and comprising a plurality of first channels (210) such that a first reactant can flow beneath the hydrogen gas and the air; and a second separator (300) arranged on the second side of the catalyst layer (100) and comprising a plurality of second channels (310) arranged in a direction perpendicular to the first channels (210), wherein each of the second channels (310) comprises a plurality of vents (320) such that a second reactant can flow under the hydrogen gas and the air in a direction perpendicular to the second channels (310), and wherein the second reactant flows under the hydrogen gas and the air parallel to a longitudinal direction of the first channels (310) through the vents (320).

Description

TECHNICAL FIELD

[0001] The present invention relates to a fuel cell, and more particularly to a fuel cell capable of improving diffusion of a reaction gas and generating a more uniform surface pressure of a reaction surface by changing a channel structure of a fuel cell separator. BACKGROUND

[0002] Typically, a metal separator is applied to a fuel cell, wherein the metal separator comprises channels for a reactant and cooling water, a pair of gas diffusion layers (GDLs) 12 for facilitating the diffusion of the reactant, and a membrane electrode assembly (MEA) 11 in which a chemical reaction takes place and which is disposed between the pair of gas diffusion layers (GDLs) 12. In the metal separator, channel portions 41 in which the reactant gas flows in the same direction as a flow direction of the reactant gas and land portions 42 in contact with the GDLs 12 are repeatedly arranged, and passages of an anode separator 30 and a cathode separator 20 are symmetrical to each other, so that a space between the anode separator 30 and the cathode separator 20 is used as a cooling channel, as shown in Fig. 1 is shown.

[0003] Furthermore, to maximize fuel cell performance, a tight channel spacing of separators 20 and 30 may be required to improve surface pressure on the GDL 12 and MEA 11, and then the GDL 12 may be able to maintain a constant permeability across the entire reaction surface. However, a decrease in the channel spacing of separators 20 and 30 may be limited due to a defect such as a crack or pop that occurs during manufacturing, and other performance-degrading factors may occur due to such defects.

[0004] For example, the diffusion of reaction gas and the discharge properties of generated water may deteriorate. If the channel pitch is substantially large, stress may be directed to the land portion 42 where the separator and the GDL 12 come into contact with each other, so that surface pressure cannot be applied sufficiently uniformly. As a result, a porous structure of the GDL 12 may be destroyed, so that the permeability of the GDL 12 may deteriorate, and the diffusion of the reaction gas and a discharge property of generated water may deteriorate. Furthermore, if the stress in the channel portion 41 is reduced, the GDL 12 may penetrate into the channel portion 41 to deteriorate the fluidity of the reactant flow.

[0005] Furthermore, damage to a membrane may occur if the web portion 42, where the structure of the GDL 12 is destroyed, and carbon fibers may penetrate into a membrane, causing membrane damage. Furthermore, non-uniformity in electrical conductivity may occur. In the channel portion 41 where the GDL 12 is exposed, the reaction gas can be uniformly supplied to cause an active chemical reaction. However, if the surface pressure between the GDL 12 and the MEA 11 is insufficient, contact resistance may increase, inhibiting the movement of electrons generated by a reaction.

[0006] Regarding the prior art, reference can also be made to US Pat. No. 6,296,964 B1, which shows a fuel cell with uniformly shaped separators, comprising molded channels with evenly spaced perforations. In stacked separators, the channels are offset by 90 degrees from each other, with the channels of all separators having perforations.

[0007] The items described as prior art are provided merely to promote an understanding of the background of the present invention and should not be considered as corresponding to the prior art known to one of ordinary skill in the art. SUMMARY

[0008] The invention is defined by independent claim 1. Advantageous embodiments are subject to the dependent claims. In one aspect, the present invention provides a fuel cell in which a channel is formed in a direction perpendicular to a flow direction of a reaction gas; opening portions penetrating each channel are formed at regular intervals in wall surfaces of the channels to form flow paths of the reaction gas; and separators corresponding to an anode and a cathode may be formed in each channel to overlap with each other.

[0009] According to the present invention, there is provided a fuel cell comprising: a catalyst layer wherein hydrogen gas or air is introduced thereinto through both surfaces thereof; a first separator disposed on a first side of the catalyst layer and comprising a plurality of first channels for allowing a first reactant to flow among the hydrogen gas and the air; and a second separator disposed on a second side of the catalyst layer and comprising a plurality of second channels arranged in a direction perpendicular to the first channels.Each of the second channels includes a plurality of vents to allow a second reactant to flow beneath the hydrogen gas and air in a direction perpendicular to the second channels, wherein the second reactant flows beneath the hydrogen gas and air through the vents parallel to a longitudinal direction of the first channels.

[0010] The first separator and the second separator may be bent in a zigzag shape, and their end portions may be formed on first side surfaces thereof, respectively. The bent portions may contact the catalyst layer to form closed circuits between the respective separators and the catalyst layer, thereby creating the first and second channels. The vent holes may be formed in inclined surfaces of the second separator connecting a first end and a second end of the second separator that are bent, and the vent holes may be formed at predetermined intervals along a longitudinal side of the second channel.

[0011] The vents formed in any one of a plurality of inclined surfaces may be selectively arranged with the vents formed in an inclined surface adjacent to any one of the inclined surfaces. Each of the vents formed in any one of a plurality of inclined surfaces may be formed at a position corresponding to a substantially central portion between two vents formed in the inclined surface adjacent to any one of the inclined surfaces.

[0012] The fuel cell may further comprise an airtight plate covering the second side surface of at least one of the first separator and the second separator. A contact area between the first side surface of the first separator and the catalyst layer may be larger than a contact area between the second side surface of the first separator and the airtight plate. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows a structure of an exemplary fuel cell in the prior art; Fig. 2 shows a structure of an exemplary fuel cell according to an embodiment of the present invention; Fig. 3 shows a fluid flow of an exemplary fuel cell according to an embodiment of the present invention; Fig. 4 shows a sectional view of an exemplary fuel cell according to an embodiment of the present invention; and Fig. 5 shows output voltages according to an air equivalent ratio of the fuel cell according to an embodiment of the present invention and the fuel cell in the prior art. DETAILED DESCRIPTION

[0013] The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the invention. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It is further understood that the terms "comprise" and / or "comprising," when used in this specification, describe the presence of the specified features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more features, integers, steps, operations, elements, components, and / or groups thereof. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0014] Hereinafter, a fuel cell according to an embodiment of the present invention will be described with reference to the accompanying drawings.

[0015] Fig. 2 shows an exemplary fuel cell according to an embodiment of the present invention. The fuel cell is configured to include: a catalyst layer 100 having hydrogen gas or air introduced therein through both surfaces thereof; a first separator 200 disposed on a first side of the catalyst layer 100 and including a plurality of first channels 210 such that a first reactant can flow among the hydrogen gas and the air; and a second separator 300 disposed on the second side of the catalyst layer 100 and including a plurality of second channels 310 arranged in a direction perpendicular to the first channels 210. Each of the second channels 310 includes a plurality of vents 320 such that a second reactant can flow among the hydrogen gas and the air in a direction perpendicular to the second channels 310.The first reactant may be different from the second reactant.

[0016] Furthermore, cross sections of the first separator 200 and the second separator 300 may be bent in a zigzag shape to form bent first ends 201 and 301 and second ends 203 and 303, respectively, first side surfaces of the first separator 200 and a second separator 300 may come into contact with the catalyst layer 100, and the first ends 201 and 301 that are bent may come into contact with the catalyst layer 100 to form closed circuits between the respective separators 200 and 300, thereby forming the first and second channels 210 and 310.

[0017] Furthermore, the catalyst layer 100 may be an assembly formed from a membrane electrode assembly (MEA) 110 of the fuel cell and a pair of gas diffusion layers (GDLs) bonded to both surfaces of the membrane electrode assembly, as shown in Fig. 2. In particular, the first and second channels 210 and 310 may contact outer surfaces of the gas diffusion layer 120. Hydrogen gas may flow in the first channels 210 as the first reactant, and oxygen gas may flow in the second channels 310 as the second reactant. Without being bound to any particular examples, materials or reactants flowing in the first and second channels 210 and 310 may be changed depending on various embodiments of the invention.

[0018] The first and second channels 210 and 310 may be arranged to overlap with each other so that uniform surface pressure can be applied to the catalyst layer 100 and stress can be distributed across a contact surface to prevent stress concentration, thereby preventing damage to the catalyst layer 100 and deteriorating reactivity. The vent hole 320 may be formed in the inclined surfaces of the second separator 300 connecting the first end 301 and the second end 303 of the second separator 300, which are bent toward each other. The vent hole may be formed at predetermined intervals along a longitudinal side of the second channel 310.The ventilation openings 320 formed in any one of a plurality of inclined surfaces 302 may be arranged alternately with the ventilation openings 320 formed in an inclined surface 302 adjacent to one of the inclined surfaces 302.

[0019] Fig. Figure 3 shows a fluid flow of an exemplary fuel cell according to an embodiment of the present invention and is a plan view of Fig. 2. The hydrogen gas or oxygen gas may be introduced into any one of the plurality of vents 320, and the introduced hydrogen gas or oxygen gas may be introduced into the respective second channels 310 or spaces between the second channels 310. The introduced hydrogen gas or oxygen gas may be repeatedly introduced into the spaces between the second channels 310 and the respective second channels 310 through the vents 320.

[0020] The introduced hydrogen gas and oxygen gas can move in a direction perpendicular to a longitudinal direction of the second channels 310, that is, in a direction parallel to a longitudinal direction of the first channels 210, through the vent holes 320, and can move a predetermined distance within the second channels because the respective vent holes 320 are arranged at predetermined intervals and are arranged with the vent holes 320 formed adjacent thereto in the inclined surface 302. As a result, a reaction area and reaction time with the catalyst layer 100 can increase. Furthermore, increased diffusion of the hydrogen gas or oxygen gas can improve the reaction efficiency to the introduced hydrogen gas or oxygen gas.

[0021] Specifically, each of the vent holes 320 formed in any one of the plurality of inclined surfaces 302 may be formed at a position corresponding to a substantially central / middle portion between two vent holes 320 formed in the inclined surface 302 adjacent to any one of the inclined surfaces 302. Since the introduced hydrogen gas or air can equalize the distances between the vent holes 320 with respect to all of the vent holes 320 as the gases move through the plurality of vent holes 320, uniform diffusion can be maintained, and uniform reactivity can be generated throughout the catalyst layer 100.

[0022] An effect of the diffusion of the fuel cell separator in the present invention can be clearly seen from Fig. 5 can be taken. Fig. Figure 5 shows a graph illustrating the diffusion of introduced air when the air is introduced into the second channels 310 and the output voltages according to the amount of supplied air in the prior art and in an embodiment of the invention. Since the diffusion of the reaction gas in an embodiment of the present invention, and thus the fluidity of fuel supplied to the fuel cell, can be improved, the performance may not be reduced even if a reduced amount of fuel is supplied. Furthermore, as shown in Fig. As shown in Figure 5, although an air equivalent ratio is reduced, the reduction width in the voltage output by the fuel cell according to an embodiment of the present invention can be smaller than that of the prior art fuel cell. Thus, the diffusion of the reaction gas can be improved in the present invention.

[0023] Meanwhile, as in Fig. As shown in Fig. 2, the fuel cell according to an embodiment of the present invention may further include an airtight plate 400 covering the second side surface of at least one of the first separator 200 and the second separator 300. The airtight plate 400 may come into contact with the second side surface of the first separator 200 or the second separator 300, particularly the bent second end 203 or 303. Accordingly, closed circuits may be formed in a space between the first separator 200 and the airtight plate 400 and a space between the second separator 300 and the airtight plate 400, thereby forming a path for a coolant to flow between the first channels 210 but preventing the coolant from being introduced into the spaces between the second channels.

[0024] The airtight plate 400 may be provided on one of the second side surface of the first separator 200 and the second side surface of the second separator 300. The airtight plate 400 may be configured so that the second side surface of the first separator 200 can contact the first side surface of the airtight plate 400, and the second side surface of the second separator 300 can contact the second side surface of the airtight plate 400 when a plurality of fuel cells are stacked. Alternatively, the airtight plate 400 may be arranged on the second side surfaces of the first separator 200 and the second separator 300, respectively, so that they contact each other when the plurality of fuel cells are stacked.

[0025] The assembly of the catalyst layer 100, the first separator 200, the second separator 300, and the airtight plate 400 described above can be pressed by an external force so that they can be kept in close contact, and can further be fully or partially bonded to each other so that the fuel cell can be formed integrally with the catalyst layer 100, the first separator 200, the second separator 300, and the airtight plate 400. Various bonding methods, such as a welding method, an adhesive method, a screwing / bolting method, a riveting method, and the like, can be used to connect the components.

[0026] Fig. 4 shows a sectional view of an exemplary fuel cell along the line AA of Fig. 2. In particular, a contact area between the first side surface of the first separator 200 and the catalyst layer 100 may be larger than a contact area between the second side surface of the first separator 200 and the airtight plate 400, as shown in Fig.4. Meanwhile, the second separator 300 may have a structure in which a coolant cannot flow, since inner and outer portions of the second channels 310 may communicate with each other due to the plurality of vents 320. Accordingly, to compensate for a limited flow of the coolant, the sizes of passages through which the coolant flows may be increased.Accordingly, the contact area between the first side surface of the first separator 200 and the catalyst layer 100 may be configured to be larger than the contact area between the second side surface of the first separator 200 and the airtight plate 400 to increase an amount of coolant flowing in the space between the first separator 200 and the airtight plate 400 and to increase an area of ​​the catalyst layer 100 supported by a separator 200, thereby applying a more uniform surface pressure to the catalyst layer 100.

[0027] According to various embodiments of the fuel cell having the structure described above, the surface pressure applied to the catalyst layer 100 can be increased and the diffusion of the reaction gas can be improved, thereby improving the performance of the fuel cell. Furthermore, the first and second channels 210 and 310 can be arranged perpendicular to each other, thereby improving the structural stability of the fuel cell.

[0028] Although the present invention has been illustrated and described with reference to various embodiments, it will be apparent to one of ordinary skill in the art that the present invention may be modified and varied in various ways without departing from the spirit and scope of the present invention as defined by the following claims.

Claims

[1] Fuel cell, comprising: a catalyst layer (100) wherein hydrogen gas or air is introduced therethrough through a first surface and a second surface thereof; a first separator (200) disposed on a first side of the catalyst layer (100) and comprising a plurality of first channels (210) such that a first reactant can flow beneath the hydrogen gas and the air; and a second separator (300) arranged on the second side of the catalyst layer (100) and comprising a plurality of second channels (310) arranged in a direction perpendicular to the first channels (210), wherein each of the second channels (310) comprises a plurality of vents (320) such that a second reactant can flow under the hydrogen gas and the air in a direction perpendicular to the second channels (310), and wherein the second reactant flows under the hydrogen gas and the air parallel to a longitudinal direction of the first channels (310) through the vents (320). [2] The fuel cell according to claim 1, wherein the first separator and the second separator (300) are bent in a zigzag shape and first and second end portions are formed on first side surfaces thereof, respectively, and are bent to come into contact with the catalyst layer (100) to form closed circuits between the first and second separators (200, 300) and the catalyst layer (100), thereby forming the first and second channels (310). [3] The fuel cell according to claim 2, wherein the vent holes (320) are formed in inclined surfaces of the second separator (300) connecting a first end and a second end of the second separator (300) which are bent, and the vent holes (320) are formed at predetermined intervals along a longitudinal side of the second channel. [4] The fuel cell according to claim 3, wherein the vent holes (320) formed in any one of a plurality of inclined surfaces are selectively arranged with the vent holes (320) formed in an inclined surface adjacent to any one of the inclined surfaces. [5] The fuel cell according to claim 3, wherein each of the vent holes (320) formed in any one of a plurality of inclined surfaces is formed at a position corresponding to a substantially central portion between two vent holes (320) formed in the inclined surface adjacent to any one of the inclined surfaces. [6] The fuel cell according to claim 2, further comprising an airtight plate (400) covering a second side surface of at least one of the first separator (200) and the second separator (300). [7] The fuel cell according to claim 6, wherein a contact area between a first side surface of the first separator and the catalyst layer (100) is larger than a contact area between the second side surface of the first separator (200) and the airtight plate (400).

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