Fuel cell separator with 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 condensed water can be smoothly transferred and discharged, and the overlapping portions of the fuel electrode separators and the air electrode separators on both sides are in point contact to have the minimum area, thereby minimizing the occurrence of water accumulation due to the pressing of the gas diffusion layer and the decrease in 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 supply industrial, household, and vehicle power, and can also be used to supply power to 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 consists of a solid polymer electrolyte membrane capable of transferring hydrogen ions, and cathode and anode electrode layers 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 are formed to form channels for supplying hydrogen and air.

[0005] In this configuration, channel ribs are provided on each anode separator and cathode separator, as shown in the following patent document, forming multiple passages through which hydrogen and air flow, respectively. However, as shown in Figure 1(b), the gas diffusion layer is compressed by the channel ribs on both sides, causing water to accumulate. When water accumulates, the gas supply is cut off, reducing the reactive electrode area and resulting in a decrease in performance. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Korean Registered Patent Publication No. 10-2131702 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention was devised to solve the aforementioned problems, and its objective is to provide a fuel cell separator that minimizes the pressure on the gas diffusion layer, the formation of water accumulation, and the deterioration of electrode performance by shaping the channel structure of the separator to be inclined to facilitate the transfer and discharge of condensed water, and by ensuring that the overlapping portions of the fuel electrode separator and air electrode separator on both sides are in point contact and have the smallest possible surface area. [Means for solving the problem]

[0008] To achieve the above objectives, the present invention is realized by embodiments having the following configuration.

[0009] According to one embodiment of the present invention, the fuel cell separator according to the present invention includes a fuel electrode separator and an air electrode separator, each formed on both sides of a membrane electrode assembly, forming passages for the flow of fuel and air, respectively, wherein the fuel electrode separator includes a first channel that protrudes toward the membrane electrode assembly and is formed in multiple quantities to be separated by a certain distance, forming a plurality of passages for the flow of fuel, and the air electrode separator includes a second channel that protrudes toward the membrane electrode assembly and is formed in multiple quantities to be separated by a certain distance, forming a plurality of passages for the flow of air, wherein the first channel and the second channel are each formed at a certain angle inclined along the longitudinal direction of the electrode and are formed to be inclined at different angles to each other and to be in point contact.

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

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

[0012] According to another embodiment of the present invention, the fuel cell separator according to the present invention is characterized in that the area over which the first channel and the second channel make point contact is in the range of 10 to 20% of the total electrode area.

[0013] According to another embodiment of the present invention, in a fuel cell separator according to the present invention, the fuel electrode separator includes a first spatial separation portion formed at regular intervals along the first channel, where the linearly formed first channel is divided into a plurality of parts to form a certain space, and a first fluid space portion formed between a plurality of rows of first channels through which fuel and condensed water flow, and the air electrode separator includes a second spatial separation portion formed at regular intervals along the second channel, where the linearly formed second channel is divided to form a certain space, and a second fluid space portion formed between a plurality of rows of second channels through which air and condensed water flow, and the first and second spatial separation portions are closed by the first and second channels, respectively, in a direction perpendicular to the direction in which fuel or air flows. [Effects of the Invention]

[0014] The present invention can achieve the following effects through the above-described embodiment and the configuration, combination, and usage relationship described later.

[0015] The present invention has the effect of minimizing the pressure on the gas diffusion layer, which can cause water to accumulate and degrade electrode performance, by forming the channel structure of the separator inclined to facilitate the transfer and discharge of condensed water, and by ensuring that the overlapping portions of the fuel electrode separator and air electrode separator on both sides are in point contact and have the smallest possible surface area. [Brief explanation of the drawing]

[0016] [Figure 1] This is a reference diagram to explain the problems with conventional fuel cell stack structures. [Figure 2] This is a plan view showing a fuel cell separator according to one embodiment of the present invention. [Figure 3] Figure 2 is a reference diagram illustrating the point contact structure using a separator. [Figure 4] This is a reference diagram showing the state in which the fuel electrode separator and the air electrode separator intersect. [Figure 5]This is a reference diagram showing the detailed structure of the separator. [Figure 6] This is a diagram showing the structures of a conventional fuel electrode separator (a), an air electrode separator (b), and the formation position of a moisture condensation part (c). [Figure 7] This is a diagram showing a fuel electrode separator with another conventional structure and the process of forming flooding thereby. [Figure 8] This is a diagram showing a fuel electrode separator with another conventional structure and the process of alleviating flooding thereby. [Figure 9] This is a diagram showing the problems of FIG. 8.

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 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 water accumulation, and there is a problem that performance reduction occurs 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 forms 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 condensed water without accumulation. A detailed description of the first channel 11 and the second channel 31 will be described later.

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

[0024] Therefore, the fuel and air supplied through the space provided by the first channel 11 and the second channel 31 can be uniformly supplied across the entire electrode, enabling efficient power generation, while also reducing performance degradation due to point contact.

[0025] Furthermore, as shown in Figure 4, the length α and angle β of the first channel 11 and the second channel 31 can be appropriately adjusted to minimize the overlapping area of ​​the first channel 11 and the second channel 31 while maintaining the support effect.

[0026] In this case, it is preferable that the area where the first channel 11 and the second channel 31 overlap is in the range of 10 to 20% of the total electrode area, and more preferably, the first channel 11 and the second channel 31 are formed inclined at the same angle as the length direction L of the electrode and have a symmetrical shape with respect to each other, thereby enabling a more uniform supply of fuel and air and minimizing the contact area.

[0027] To describe the fuel electrode separator 1 and air electrode separator 3 in more detail, as shown in Figure 5, the fuel electrode separator 1 is formed by dividing a linearly formed first channel 11 into multiple sections, and forming multiple first spatial separation sections 12 at regular intervals in the divided spaces, and forming a first fluid space section 13 through which fuel and condensed water flow between the multiple rows of first channels 11. The air electrode separator 3 can be formed with a shape symmetrical to that of the fuel electrode separator 1, and can include a second spatial separation section 32 and a second fluid space section 33, similar to the fuel electrode separator 1. The second channel 31, second spatial separation section 32, and second fluid space section 33 of the air electrode separator 3 have the same function and effect as the first channel 11, first spatial separation section 12, and first fluid space section 13, except that their orientation is different. Therefore, in the following, only the first channel 11, first spatial separation section 12, and second spatial separation section 32 will be described, and the description of the second channel 31, second spatial separation section 32, and second fluid space section 33 will be omitted.

[0028] Conventional fuel electrode separators 200 are formed in a flat plate shape as shown in Figure 6. Due to the low temperature on the air inlet side, a water condensation zone is formed where moisture condenses, and a flooding phenomenon occurs due to the stagnation of the water condensation zone. In such cases, not only is the movement of hydrogen blocked, but the increase in current density due to the reduction in reaction electrodes causes a hot spot to form at the air outlet where the temperature rises rapidly, damaging the electrodes.

[0029] Therefore, as shown in Figure 7, it is conceivable to form a partition wall 201 in the fuel electrode separator 200 to create a hydrogen flow direction perpendicular to the air flow direction on the air electrode separator 100 side. In this case, the flooding phenomenon can be mitigated compared to Figure 6, but because the hydrogen flow path is formed to be long in the direction of the electrode, water easily accumulates in the cold zone, causing the flooding phenomenon as shown in Figure 6. Furthermore, the fuel electrode separator 200, which is formed to be long in the length direction of the electrode, is prone to deformation due to the stacking of structures, and condensed water can accumulate in the deformed parts, which further exacerbates the problem of the flooding phenomenon.

[0030] Furthermore, in order to mitigate the stagnation phenomenon caused by condensed water, the partition wall 201 can be formed to separate and have a pattern shape for a certain period of time, as shown in Figure 8. This allows for the flow of hydrogen and water perpendicular to the electrode, thereby mitigating the flooding phenomenon. However, as shown in Figure 9, the gas diffusion layer (GDL) 300 is pressed by the protrusion 101 of the air electrode separator 100, causing deformation, and the condensed water stagnates in the cross section. As a result, cooling remains difficult in the high-temperature area (air outlet), leading to a dry-out phenomenon, which degrades the performance of the fuel cell.

[0031] Therefore, as shown in Figure 5, the present invention creates a space in which condensed water can be forcibly transported together with fuel and air in a direction inclined with respect to the length of the electrode, thereby minimizing the stagnation of condensed water and allowing the high-temperature section (air outlet section) to be cooled by the transport of condensed water, thus mitigating the dry-out phenomenon. Furthermore, even when the temperature of the external air rises, the cooling effect can be maintained by the transport 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, thereby partitioning the hydrogen transfer path. In particular, as shown in Figure 2, the first channel 11 can be formed at an angle greater than 0° but less than 90° with respect to the length L of the electrode, so that condensed water at the inlet side can be transferred to the outlet side along the first fluid space 13 between the first channels 11. Furthermore, multiple first channels 11 can be formed in a line separated by a certain distance, and a first spatial separation section 12 can be formed between the first channels 11 formed in a line so that the fuel and condensed water can flow.Therefore, multiple first channels 11 can be formed in a line, with multiple rows running parallel to each other, to have a fine pattern shape, thereby preventing stagnation of condensed water and minimizing flooding and dry-out phenomena through forced transfer. Furthermore, by forming the first channel 11 with a fine pattern shape that separates them at a certain distance, the rigidity of the separator can be ensured, thereby preventing structural damage.

[0033] The first spatial separation section 12 is a space formed by dividing the linear first channel 11, and is formed in a line along the first channel 11 at regular intervals. Therefore, fuel and condensed water can be transferred between adjacent first fluid space sections 13 via the first spatial separation section 12, thereby minimizing stagnation of fuel and condensed water flow, and effectively ensuring smooth fuel supply and cooling and prevention of dry-out by transferring condensed water to the high-temperature section. Furthermore, the first spatial separation section 12 is closed by the first channel 11 in the direction of fuel flow, i.e., in the direction perpendicular to the direction in which the first fluid space section 13 is formed, so that condensed water moving towards the high-temperature section can be transmitted throughout the entire first fluid space section 13 between the first channels 11, thereby further effectively blocking flooding due to condensed water stagnation and dry-out due to high temperatures. In other words, if multiple rows of first spatial separation sections 12 are formed to communicate with each other on a straight line perpendicular to the direction of fuel travel, condensed water passing through the first spatial separation section 12 can flow to the next row of first spatial separation section 12 and escape. In this case, condensed water cannot be properly transported between the first channels 11 in the direction of fuel travel, causing condensed water to stagnate and resulting in a flooding phenomenon. Furthermore, if condensed water cannot be properly transported to the high-temperature section, a dry-out phenomenon occurs as in conventional designs. Therefore, by arranging the first spatial separation section 12 to be closed by the first channels 11 in a direction perpendicular to the direction of fuel travel, condensed water passing through the first spatial separation section 12 can flow through the space between the first channels 11 along the direction of fuel travel, thereby effectively blocking condensed water stagnation and the dry-out phenomenon.

[0034] The first fluid space 13 is formed between parallel, inclined first channels 11 to form a space through which fuel and condensate flow. Since the first channels 11 have an angle greater than 0° but less than 90°, the first fluid space 13 is also formed with an inclination so that it has the same angle greater than 0° but less than 90°. Therefore, the condensate can be transported towards the high-temperature side along the first fluid space 13, mitigating the stagnation phenomenon, and since flow also occurs through the first space separation section 12, the stagnation phenomenon can be further minimized. Accordingly, the first fluid space 13 is formed in multiple rows on the overall separator, parallel to each other in an inclined state, allowing for a smooth supply of fuel to the overall electrode, thereby maximizing the reaction area of ​​the electrode and increasing power production efficiency.

[0035] Although the applicant has described various embodiments of the present invention, these embodiments are merely one way of realizing the technical idea of ​​the present invention, and any modifications or alterations should be interpreted as falling within the scope of the present invention as long as they realize the technical idea of ​​the present invention. [Explanation of Symbols]

[0036] *Explanation of symbols used in drawings 1. Fuel electrode separator 11. Channel 1 12 First spatial separation part 13. First fluid space section 3. Air electrode separator 31 Second Channel 32 Second space separation part 33 Second Flow Space Section *Explanation of symbols related to prior art 100 Air electrode separator 101 Protrusion 200 Fuel electrode separator 201 Bulkhead 300 Gas diffusion layer

Claims

1. The membrane electrode assembly includes a pair of fuel electrode separators and an air electrode separator, each formed on both sides of the electrode assembly, which form passages for the flow of fuel and air, respectively. The aforementioned fuel electrode separator is, It includes a first channel that protrudes toward the membrane electrode assembly and is formed in multiple locations to be isolated from each other for a certain period of time, forming multiple passages through which fuel flows. The aforementioned air electrode separator is, It includes a second channel that protrudes toward the membrane electrode assembly and is formed in multiple locations to isolate it from the surrounding area for a certain period of time, forming multiple passages through which air flows. The first channel and the second channel are each formed at a constant angle inclined along the longitudinal direction of the rectangular fuel electrode separator and the air electrode separator, and are formed to be inclined at different angles to each other and to make point contact. The aforementioned fuel electrode separator is, The first channel, which is formed in a straight line, is divided into a plurality of parts to form a certain space, and the first spatial separation portion is formed at a certain interval along the first channel, It includes a first fluid space formed between a plurality of rows of first channels through which fuel and condensed water flow, The aforementioned air electrode separator is, The second channel, which is formed in a straight line, is divided to form a certain space, and the second spatial separation portion is formed at a certain interval along the second channel, It includes a second fluid space formed between multiple rows of second channels through which air and condensed water flow, The first and second spatial separation sections are, A fuel cell separator characterized in that, by first and second channels, respectively, prevent the flow of fuel or air in the direction perpendicular to the direction in which the fuel or air flows.

2. The first channel is, The rectangular fuel electrode separator and the air electrode separator are formed inclined to have an angle greater than 0° and less than 90° with respect to the longitudinal direction of the fuel electrode separator and the air electrode separator, The fuel cell separator according to claim 1, characterized in that the second channel is formed inclined to have an angle greater than 90° and less than 180° with respect to the same longitudinal direction.

3. The first channel and the second channel are, The fuel cell separator according to claim 1, characterized in that it has the same angle and is formed to be tilted in opposite directions.

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

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