Fuel cell separator having a point contact channel structure

Abstract

The present invention relates to a fuel cell separator. More specifically, the channel structure of the separator is formed to be inclined so that the transfer and discharge of condensed water can be smoothly performed. By making the overlapping portion of the fuel electrode separator and the air electrode separator on both sides in point contact with the smallest area, it is possible to minimize the occurrence of water pooling due to the gas diffusion layer being pressed and the degradation of electrode performance. The present invention relates to a fuel cell separator having a point contact channel structure.

Description

Technical Field

[0001] The present invention relates to a fuel cell separator. More specifically, the channel structure of the separator is formed to be inclined so that the transfer and discharge of condensed water can be smoothly performed, and the overlapping portions of the fuel electrode separators and the air electrode separators on both sides are in point contact and have the minimum area, thereby minimizing the occurrence of water pooling due to the pressing of the gas diffusion layer and the reduction of electrode performance. The present invention relates to a fuel cell separator having a point contact channel structure.

Background Art

[0002] A fuel cell is an energy conversion device that electrochemically reacts the chemical energy of a fuel to convert it into electrical energy. It can be used not only to supply industrial, household, and vehicle power but also to supply power for small electrical / electronic products and portable devices.

[0003] There are various types of fuel cells, but polymer electrolyte membrane fuel cells (PEMFCs) with high power density are mainly used. The membrane electrode assembly (MEA) is located in the innermost part. The membrane electrode assembly is composed of a solid polymer electrolyte membrane capable of moving hydrogen ions and electrode layers (cathode and anode) with a catalyst coated on both sides of the electrolyte membrane so that hydrogen and oxygen can react.

[0004] In addition, gas diffusion layers (GDLs) are formed on both sides of the membrane electrode assembly (MEA) to allow hydrogen and oxygen to diffuse to the electrodes. On both sides of the gas diffusion layer, as shown in FIG. 1, anode separators and cathode separators that form passages for supplying hydrogen and air are formed.

[0005] At this time, each anode separator and cathode separator has a channel rib protruding as in the following patent document to form a plurality of passages through which hydrogen and air flow respectively. However, as shown in Fig. 1(b), the gas diffusion layer is compressed by the channel ribs on both sides, resulting in the generation of water accumulation. When water accumulation occurs, the gas supply is blocked, reducing the reactive electrode area and causing a problem of performance degradation.

Prior Art Document

Patent Document

[0006]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0007] The present invention was devised to solve such problems. The purpose is to form the channel structure of the separator to be inclined so that the transfer and discharge of condensed water are smoothly performed, and the overlapping portions of the fuel electrode separator and the air electrode separator on both sides are in point contact with the smallest area, thereby minimizing the occurrence of water accumulation due to the pressing of the gas diffusion layer and the degradation of electrode performance. The present invention aims to provide a fuel cell separator.

Means for Solving the Problems

[0008] To achieve the above object, the present invention is realized by an embodiment having the following configuration.

[0009] According to an embodiment of the present invention, a fuel cell separator according to the present invention includes a pair of fuel electrode separators and air electrode separators formed on both sides of a membrane electrode assembly, each forming a passage through which fuel and air flow. The fuel electrode separator includes a first channel that protrudes toward the membrane electrode assembly side and is formed in a plurality of numbers so as to be spaced apart at regular intervals to form a plurality of passages through which fuel flows. The air electrode separator includes a second channel that protrudes toward the membrane electrode assembly side and is formed in a plurality of numbers so as to be spaced apart at regular intervals to form a plurality of passages through which air flows. The first channel and the second channel are each formed to be inclined at a certain angle along the length direction of the electrode, and are formed to be inclined at different angles and in point contact with each other.

[0010] According to another embodiment of the present invention, in the fuel cell separator according to the present invention, the first channel is formed to be inclined so as to have an angle greater than 0° and less than 90° with respect to the length direction of the electrode, and the second channel is formed to be inclined so as to have an angle greater than 90° and less than 180° with respect to the same length direction.

[0011] According to another embodiment of the present invention, in the fuel cell separator according to the present invention, the first channel and the second channel have the same angle and are formed to be inclined in opposite directions.

[0012] According to another embodiment of the present invention, in the fuel cell separator according to the present invention, the area where the first channel and the second channel are in point contact is in the range of 10% to 20% of the entire electrode area.

[0013] According to another embodiment of the present invention, in the fuel cell separator according to the present invention, the fuel electrode separator forms a certain space while the plurality of linearly formed first channels are divided, and a first space separation part formed at regular intervals along the first channel, and a first flow space part formed between the first channels forming a plurality of columns and through which fuel and condensed water flow. The air electrode separator divides the linearly formed second channel to form a certain space, and includes a second space separation part formed at regular intervals along the second channel, and a second flow space part formed between the second channels forming a plurality of columns and through which air and condensed water flow. The first and second space separation parts are each closed by the first and second channels in a direction perpendicular to the direction in which fuel or air flows, respectively.

Advantages of the Invention

[0014] The present invention can obtain the following effects according to the above-described embodiments and the configurations, couplings, and usage relationships to be described later.

[0015] The present invention has the effect of forming the channel structure of the separator to be inclined so that the transfer and discharge of condensed water are smoothly performed, and making the overlapping portions of the fuel electrode separator and the air electrode separator on both sides in point contact with the smallest area, thereby minimizing the occurrence of water accumulation due to the pressing of the gas diffusion layer and the deterioration of the electrode performance.

Brief Description of the Drawings

[0016]

Figure 1

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Figure 9

Embodiments for Carrying Out the Invention

[0017] Hereinafter, a preferred embodiment of a fuel cell separator having a point contact channel structure according to the present invention will be described in detail with reference to the accompanying drawings. In describing the present invention, when it is determined that a specific description of a known function or configuration may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Throughout the specification, when a certain part includes a certain component, this means that, unless otherwise specified, it does not exclude other components and may further include other components.

[0018] Referring to FIGS. 2 to 5, a fuel cell separator having a point contact channel structure according to an embodiment of the present invention will be described. The fuel cell separator includes a fuel electrode separator 1 and an air electrode separator 3 that are formed in a pair on both sides of a membrane electrode assembly and form passages through which fuel and air flow, respectively. Each of the fuel electrode separator 1 and the air electrode separator 3 includes a first channel 11 and a second channel 31 that are formed so as to have a certain inclination with respect to the length direction of the electrode, thereby forming passages through which fuel and air flow. Here, the fuel can mean hydrogen.

[0019] The first channel 11 and the second channel 31 are formed to be inclined at a certain angle with respect to the length direction L of the electrode, so as to prevent the accumulation of condensed water and enable the smooth transfer and discharge of the condensed water. In particular, the first channel 11 and the second channel 31 are formed to be inclined at different angles, so that a point contact is formed at the overlapping portion of the first channel 11 and the second channel 31 sandwiching the membrane electrode assembly, minimizing the pressing of the gas diffusion layer and preventing the occurrence of water accumulation and performance reduction according to the pressing of the gas diffusion layer.

[0020] As described above in the background art, when the channel ribs of the anode separator and the cathode separator sandwiching the membrane electrode assembly abut against each other and press the gas diffusion layer, as shown in Fig. 1(b), the gas diffusion layer is pressed by the channel ribs on both sides in the vertical direction of the electrode, resulting in the occurrence of water accumulation, and thus there is a problem of performance reduction due to the loss of the electrode area.

[0021] Therefore, in the present invention, as shown in Fig. 2, the first channel 11 of the fuel electrode separator 1 and the second channel 31 of the air electrode separator 3 are formed to be inclined at different angles, and as shown in Fig. 3, the overlapping portion S of the first channel 11 and the second channel 31 is formed to have a point contact, so that the overlapping area of the first channel 11 and the second channel 31 can be minimized.

[0022] At this time, the first channel 11 and the second channel 31 are formed to be inclined with respect to the length direction of the electrode in order to enable the transfer and discharge of the condensed water without accumulation. A detailed description of the first channel 11 and the second channel 31 in this regard will be described later.

[0023] In particular, the first channel 11 can be formed to be inclined at an angle exceeding 0° and less than 90° with respect to the length direction L of the electrode, the second channel 31 can be formed to be inclined at an angle exceeding 90° and less than 180° with respect to the length direction L of the electrode, and the first channel 11 and the second channel 31 can be formed to be inclined in opposite directions to each other.

[0024] Accordingly, it is possible to efficiently generate electric power while the fuel and air supplied by the space formed by the first channel 11 and the second channel 31 are uniformly supplied over the entire electrode, and it is possible to have an effect of reducing the performance degradation due to point contact.

[0025] Also, as shown in FIG. 4, it is possible to appropriately adjust the lengths α and angles β of the first channel 11 and the second channel 31 to maintain the supporting effect while minimizing the overlapping area of the first channel 11 and the second channel 31.

[0026] At this time, the area where the first channel 11 and the second channel 31 overlap is preferably in the range of 10% to 20% of the entire electrode area. More preferably, the first channel 11 and the second channel 31 can be formed to be inclined at the same angle as the length direction L of the electrode and have a symmetrical shape with respect to each other, whereby more uniform supply of fuel and air and minimization of the contact area can be achieved.

[0027] A more detailed description of the fuel electrode separator 1 and the air electrode separator 3 is as follows. As shown in FIG. 5, the fuel electrode separator 1 is formed such that a plurality of first channels 11 formed linearly are divided, and a plurality of first space separation portions 12 are formed at regular intervals in the divided spaces. A first flow space portion 13 through which fuel and condensed water flow can be formed between the plurality of rows of the first channels 11. Further, the air electrode separator 3 can be formed to be inclined in the opposite direction so as to have a shape symmetrical to the fuel electrode separator 1, and can include a second space separation portion 32 and a second flow space portion 33 similar to the fuel electrode separator 1. The second channel 31, the second space separation portion 32, and the second flow space portion 33 of the air electrode separator 3 are only different in direction from the first channel 11, the first space separation portion 12, and the first flow space portion 13, and have the same functions and effects. Therefore, in the following, only the first channel 11, the first space separation portion 12, and the second space separation portion 32 will be described, and the description of the second channel 31, the second space separation portion 32, and the second flow space portion 33 will be omitted.

[0028] The conventional fuel electrode separator 200 is formed in a flat plate shape as shown in FIG. 6, and a moisture condensation portion is formed due to the low temperature on the air inlet side, and a flooding phenomenon occurs due to the stagnation of the moisture condensation portion. In such a case, not only the movement of hydrogen is blocked, but also a hot spot where the temperature rapidly rises is generated at the air outlet portion due to the increase in the current density caused by the reduction of the reaction electrode, damaging the electrode.

[0029] Therefore, as shown in FIG. 7, it is conceivable to form a partition wall 201 in the fuel electrode separator 200 to form a hydrogen flow direction perpendicular to the air flow direction on the air electrode separator 100 side. In such a case, although the flooding phenomenon can be alleviated compared to FIG. 6, since the hydrogen flow path is formed long in the electrode direction, there is a problem that water easily accumulates in the cold zone and the flooding phenomenon occurs as shown in FIG. 6. Further, the fuel electrode separator 200 formed long in the length direction of the electrode is liable to be deformed by the lamination of structures, and condensed water may accumulate in the deformed portion, which may further easily cause the flooding phenomenon.

[0030] Further, in order to alleviate the stagnation phenomenon due to condensed water, as shown in FIG. 8, the partition wall 201 can be formed so as to be separated at regular intervals to have a pattern shape, thereby enabling the flow of hydrogen and water in the direction perpendicular to the electrode and alleviating the flooding phenomenon. However, as shown in FIG. 9, the gas diffusion layer (GDL) 300 is pressed by the protruding portion 101 of the air electrode separator 100 to cause deformation, and a phenomenon occurs in which condensed water stagnates due to the cross section, and thus it is still difficult to cool at the high temperature portion (air outlet portion) and a dry out phenomenon occurs, which causes a problem that the performance of the fuel cell deteriorates.

[0031] Therefore, in the present invention, as shown in FIG. 5, a space is formed so that condensed water can be forcibly transferred together with fuel and air in a direction inclined with respect to the length direction of the electrode, so as to minimize the stagnation of condensed water, and at the same time, cooling of the high temperature portion (air outlet portion) can be performed by the transfer of condensed water, so that the dry out phenomenon can be alleviated. Further, even when the temperature of the external air rises, the cooling effect can be maintained by the cooling by the transfer of condensed water, enabling stable operation.

[0032] The first channel 11 is configured to protrude from the fuel electrode separator 1 toward the anode (electrode) side and partition the hydrogen transfer path. In particular, as shown in FIG. 2, the first channel 11 can be formed to be inclined at an angle greater than 0° and less than 90° with respect to the length direction L of the electrode, so that the condensed water on the inlet side can be transferred along the first flow space portion 13 between the first channels 11 to the outlet side. Also, a plurality of the first channels 11 can be formed in a row at regular intervals, and a first space separation portion 12 can be formed between the first channels 11 formed in a row so that the fuel and the condensed water can flow. Therefore, the first channels 11 can be formed in a plurality of rows parallel to each other in a state where a plurality of them are formed in a row to have a fine pattern shape, thereby preventing the stagnation of condensed water and minimizing the flooding and dry out phenomena by forced transfer. Further, by forming the first channels 11 in a fine pattern shape separated at regular intervals, the rigidity of the separator can be ensured, and thereby structural damage can be prevented.

[0033] The first space separation part 12 is a space formed by dividing the linear first channel 11, and is formed at regular intervals in a row along the first channel 11. Therefore, through the first space separation part 12, fuel and condensed water can be transferred between adjacent first fluid space parts 13, thereby minimizing the stagnation of the flow of fuel and condensed water, and enabling the smooth supply of fuel and the cooling and prevention of dry-out by transferring the condensed water to the high-temperature part effectively. Also, the first space separation part 12 is closed by the first channel 11 in a direction perpendicular to the traveling direction of the fuel, i.e., the direction in which the first fluid space part 13 is formed, so that the condensed water heading towards the high-temperature part can be transmitted to the entire first fluid space part 13 between the first channels 11, further effectively blocking the flooding phenomenon caused by the stagnation of condensed water and the dry-out phenomenon caused by the high-temperature part. In other words, when a plurality of rows of first space separation parts 12 are formed to communicate with each other on a straight line perpendicular to the traveling direction of the fuel, the condensed water passing through the first space separation part 12 can flow out by flowing into the next row of first space separation parts 12. In this case, the transfer of condensed water between the first channels 11 in the fuel traveling direction is not properly carried out, resulting in the stagnation of condensed water and the occurrence of the flooding phenomenon. And when the transfer of condensed water to the high-temperature part is not properly carried out, the dry-out phenomenon occurs as in the conventional case. Therefore, the first space separation part 12 is closed by the first channel 11 in a direction perpendicular to the direction in which the fuel travels, so that the condensed water passing through the first space separation part 12 can flow through the space between the first channels 11 along the fuel traveling direction, effectively blocking the stagnation of condensed water and the dry-out phenomenon.

[0034] The first flow space part 13 is configured to be formed between the parallel and inclined first channels 11 to form a space for the flow of fuel and condensed water. Since the first channel 11 has an angle exceeding 0° and less than 90°, the first flow space part 13 is also inclined to have the same angle exceeding 0° and less than 90°. Thus, the condensed water can be transferred along the first flow space part 13 to the high-temperature part side while the stagnation phenomenon is alleviated. Also, since the flow is carried out through the first space separation part 12, the stagnation phenomenon can be further minimized. Therefore, the first flow space part 13 is formed in a plurality of rows on the entire separator while being parallel and inclined, so that smooth supply of fuel to the entire electrode can be achieved, thereby maximizing the reaction area of the electrode and increasing the power production efficiency.

[0035] As described above, the applicant has explained various embodiments of the present invention. However, such embodiments are merely one embodiment for realizing the technical idea of the present invention, and any modification example or correction example should be interpreted as belonging to the scope of the present invention as long as it realizes the technical idea of the present invention.

Explanation of reference numerals

[0036] *Explanation of reference numerals used in the drawings 1 Fuel electrode separator 11 First channel 12 First space separation part 13 First flow space part 3 Air electrode separator 31 Second channel 32 Second space separation part 33 Second flow space part *Explanation of reference numerals related to the prior art 100 Air electrode separator 101 Protrusion 200 Fuel electrode separator 201 Partition wall 300 Gas diffusion layer

Claims

1. A pair is formed on both sides of the membrane electrode assembly, including a fuel electrode separator and an air electrode separator that respectively form passages through which fuel and air flow. The fuel electrode separator: Includes a first channel that protrudes toward the membrane electrode assembly side and is formed in a plurality of numbers so as to be spaced apart at a certain interval to form a plurality of passages through which fuel flows. The air electrode separator: Includes a second channel that protrudes toward the membrane electrode assembly side and is formed in a plurality of numbers so as to be spaced apart at a certain interval to form a plurality of passages through which air flows. The first channel and the second channel are each formed to be inclined at a certain angle along the length direction of the electrode, and are formed to be inclined at different angles and in point contact with each other. A fuel cell separator, characterized in that.

2. The first channel: Is formed to be inclined so as to have an angle greater than 0° and less than 90° with respect to the length direction of the electrode. The second channel is formed to be inclined so as to have an angle greater than 90° and less than 180° with respect to the same length direction. The fuel cell separator according to claim 1, characterized in that.

3. The first channel and the second channel: Have the same angle and are formed to be inclined in opposite directions. The fuel cell separator according to claim 2, characterized in that.

4. The fuel cell separator according to claim 2, characterized in that the area where the first channel and the second channel are in point contact is in the range of 10% to 20% of the entire electrode area.

5. The fuel electrode separator: The first channel formed linearly is divided into a plurality of numbers while forming a certain space, and a first space separation part formed at a certain interval along the first channel; And a first flow space part formed between the first channels forming a plurality of rows, through which fuel and condensed water flow. The air electrode separator: Divides the second channel formed linearly to form a certain space, and a second space separation part formed at a certain interval along the second channel; And a second flow space part formed between the second channels forming a plurality of rows, through which air and condensed water flow. The first and second space separation parts: Are each closed by the first and second channels in a direction perpendicular to the direction in which fuel or air flows. The fuel cell separator according to claim 1, characterized in that.

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