KR100700073B1 - Fuel cell with drain structure of condensate - Google Patents

Abstract

Provided is a fuel cell to allow the condensed water generated at the inside to be discharged to the outside easily and to prevent flooding of an electrode and the clogging of a channel. The fuel cell comprises a plurality of unit cells(180) which comprises a membrane electrode assembly comprising a polymer electrolyte membrane and an electrode, a cathode separator(110) arranged at the one side of the membrane electrode assembly and having an oxidant channel, and an anode separator(120) arranged at the other side of the membrane electrode assembly and having a fuel channel; and a condensed water discharge plate(150) which is arranged at any one of the unit cells and has a condensed water channel to discharge condensed water to the entrance manifold hole(161,163) connected to the oxidant channel or the fuel channel.

Description

FUEL CELL WITH DRAIN STRUCTURE OF CONDENSATE}

1 is a partial cross-sectional view showing a fuel cell according to a first embodiment of the present invention.

2 is an exploded perspective view showing a fuel cell according to a first embodiment of the present invention.

3 is a front view illustrating the oxidant side condensate discharge plate of the fuel cell according to the first embodiment of the present invention.

4 is a front view illustrating the fuel side condensate discharge plate of the fuel cell according to the first embodiment of the present invention.

5A and 5B are partial sectional views showing a fuel cell according to a first embodiment of the present invention.

6 is a partial cross-sectional view showing a fuel cell according to a second embodiment of the present invention.

7 is a front view illustrating a condensate discharge plate of a fuel cell according to a third embodiment of the present invention.

8 is a front view illustrating a condensate discharge plate of a fuel cell according to a fourth embodiment of the present invention.

9 is a front view illustrating a condensate discharge plate of a fuel cell according to a fifth embodiment of the present invention.

10 is an exploded perspective view showing a polymer electrolyte fuel cell according to a sixth embodiment of the present invention.

The present invention relates to a fuel cell, and more particularly to a fuel cell that can easily discharge condensate.

A fuel cell consists of a pair of electrodes and separators formed on both sides of a hydrogen ion conductive polymer electrolyte membrane, and in particular, electricity and heat by electrochemically reacting a fuel gas containing hydrogen and an oxidant gas containing oxygen such as air. A battery that simultaneously generates a polymer electrolyte fuel cell is called a polymer electrolyte fuel cell. The polymer electrolyte fuel cell has excellent output characteristics compared to other fuel cells, has a low operating temperature, has fast startup and response characteristics, and is used for mobile power sources such as automobiles, as well as distributed power supplies and electronic devices such as houses and public buildings. There is a wide range of applications such as small power supply such as dragon.

The electrode comprises a catalyst layer mainly composed of carbon powder carrying a metal catalyst such as platinum group metal, and a diffusion layer formed on the outer surface of the catalyst layer and having air permeability and electron conductivity. The diffusion layer is generally made of carbon species or carbon nonwoven fabric. As such, the polymer electrolyte membrane and the electrodes formed on both sides are referred to as a membrane electrode assembly or a MEA (Membrane Electrode Assembly).

On the outside of the MEA, a mechanical separator is fixed and a conductive separator for electrically connecting adjacent MEAs to each other is provided to form a unit cell. In the part where the separator contacts the MEA, a flow path for supplying the reaction gas to the electrode surface and for carrying the surplus gas and the reaction product is formed. The flow path may be installed separately from the separator plate, but is generally formed in a groove shape on the surface of the separator plate.

In addition, since the conductive separator requires electrical conductivity, gas tightness, and corrosion resistance, conventionally, a graphite plate impregnated with resin is formed by forming a groove by cutting, or pressing a carbon composite powder or pressing a metal plate. The method is then applied by applying a corrosion resistant coating on the surface.

A typical fuel cell has a structure in which a plurality of unit cells including the MEA and an anode separator and a cathode separator disposed on both sides of the MEA are stacked, and the current is extracted at the outermost side of the stacked plurality of unit cells. The current collector plate and an insulation plate for insulation from the outside are sequentially stacked on the outer side of the current collector plate, and have a structure fixed by applying a compressive force through the fastening plate and the fastening means.

Since a fuel cell generates heat due to irreversibility during normal operation, a cooling unit in which a cooling medium flows is installed every one to three unit cells in order to efficiently discharge such heat.

The cooling unit includes a fuel gas separation plate having a fuel gas flow path at one side and a cooling flow path for a cooling medium on the opposite side, and an oxidant gas flow path at one side and a cooling flow path for the cooling medium on the opposite side. Many methods are used in which an oxidant gas separation plate provided is stacked so as to be in contact with surfaces having cooling passages.

In another method, a fuel gas separation plate having a fuel gas flow path on one side and a flat plate on which the flow path is not formed, and an oxidant gas flow path on one side and a cooling medium on the opposite side. Also used is a method in which a separator plate for oxidant gas having a cooling flow passage is formed by overlapping the cooling flow passage side and the flat plate side.

In order to supply the reaction gas and the cooling medium to the gas flow path formed on the surface of the separator plate outside the fuel cell, and to discharge the surplus gas, the reaction product and the cooling medium, at least two fuel gas, the oxidant gas and the cooling medium in the separator plate The above-described through holes are formed, and the inlet and outlet of the gas flow paths are connected to their through holes, respectively, to supply the reaction gas or the cooling medium from each of the through holes to the respective flow paths, and the surplus gas and the reaction product or the other through holes. Draining the cooling medium is a common method.

A through hole for supplying the reaction gas and the cooling medium and discharging the surplus gas, the reaction product and the cooling medium is commonly referred to as a manifold hole.

The manifold hole formed in the separator plate forms a manifold in the stacking direction in stacking a plurality of fuel cells, and this reaction gas and cooling medium supply method is called an internal manifold method.

In addition to the internal manifold method, a pipe or structure for gas distribution is formed outside the separator plate without forming a manifold hole in the separator plate to supply reaction gas or cooling medium to each unit cell, and surplus outside the separator plate. A method of forming a pipe or a structure for discharging a gas, a reaction product or a cooling medium is also used. Such a reaction gas and a cooling medium supply method are called external manifold methods.

A gasket is arranged around the electrode and the manifold so that the supplying reaction gas and the cooling medium do not leak out or mix with each other. The gasket may be integrated with the MEA to be assembled, or may be formed and assembled on a separator plate, or after the stack is assembled, a gasket may be formed by injecting a sealing agent.

As the electrolyte membrane of the polymer electrolyte fuel cell, a material of perfluorosulfonic acid type is usually used. Since the polymer electrolyte membrane shows high proton conductivity in the state of containing water, it is necessary to humidify the fuel gas or the oxidant gas and supply it to the electrode.

On the other hand, since water is generated by the reaction on the cathode side, when oxidant gas moistened at a dew point condition higher than the operating temperature of the battery is supplied, condensation of water vapor occurs in the gas flow path inside the electrode or inside the electrode to supply the reaction gas to the electrode. There is a problem that the performance is degraded by interfering.

This phenomenon is called flooding, and in the related art, a method of humidifying and supplying a dew point temperature of a reactant gas slightly lower than a fuel cell operating temperature in order to prevent flooding and to stabilize fuel cell performance has been used.

However, even when the dew point temperature of the reaction gas is humidified and lower than the fuel cell operating temperature, the insulation of the reaction gas inlet pipe cannot be perfect, and the temperature of the inlet manifold is lower than that of the electrode where heat is generated. , There is a problem that condensate occurs in the inlet pipe and the manifold during long time operation.

This condensate accumulates in the manifold, and over time, the condensate accumulates in the manifold and mixes with the fuel gas or oxidant gas into the gas flow path.

The condensate entering the gas channel blocks the flow channel and obstructs the flow of the reaction gas into the gas channel, which causes the fuel cell to run out of gas. In addition, the electrode in the vicinity of the condensed water is further accelerated condensation of the water vapor, the reaction product, deepening the flooding phenomenon.

In particular, when the clogging phenomenon of the gas oil by the condensate occurs on the anode side, it causes a deficiency of fuel gas, which causes irreversible damage of the electrode.

This is because when the load current is forcibly applied due to the lack of fuel gas, the carbon carrying the catalyst of the anode reacts with water to make electrons and protons in the absence of fuel. As a result of this reaction, a loss of the anode side catalyst occurs and a reduction in the effective electrode area leads to a decrease in fuel cell performance.

In order to solve the clogging and flooding of the gas flow path by the water condensed in the reaction gas inlet pipe and the manifold, a method of discharging the condensed water by increasing the flow rate in the flow path of the separation plate of the feed gas is used. .

However, in order to increase the feed gas flow rate, it is necessary to supply gas at a high pressure, and for this purpose, an auxiliary device power such as a gas supply blower or a compressor must be extremely increased, resulting in a problem of deterioration of system efficiency.

In addition, the water accumulated in the manifold does not flow evenly into each unit cell gas channel stacked in the fuel cell stack, but tends to be concentrated in any unit cell due to the characteristics of two-phase flow. It is known. In this situation, even if the flow rate of the reaction gas is increased, the effect of draining the water blocking the channel is not so large.

In addition, in a system equipped with a fuel cell stack, not only the stack is operated under the rated output condition, but also a low load operation in which the output is suppressed in accordance with power demand is required. In such low load operation, in order to maintain efficiency, it is necessary to make the utilization rate of fuel gas and oxidant gas into the same conditions as a rated operation.

For example, when the load is suppressed to 1/2, unless the flow rate of fuel gas or oxidant gas is also reduced to about 1/2, extra fuel gas or oxidant gas is used, so power generation efficiency is lowered.

However, if the gas utilization in the gas flow path is kept constant under low load operation, the gas flow rate in the gas flow path decreases, and condensate or reaction product water cannot be discharged to the outside of the separator plate, and the flooding phenomenon as described above occurs, resulting in stack performance. There is a problem that this decreases or becomes unstable.

The present invention has been made to solve the above problems, an object of the present invention is to prevent the condensate accumulated in the inlet pipe and inlet manifold to flow into the flow channel of the fuel gas and oxidant, and to facilitate the condensate It is to provide a fuel cell that can be discharged.

In order to achieve the above object, a fuel cell according to the present invention includes a membrane electrode assembly including a polymer electrolyte membrane and an electrode, a cathode separator disposed adjacent to one side of the membrane electrode assembly, and formed with an oxidant flow path, and the membrane electrode. A plurality of unit cells each disposed adjacent to the other side of the assembly and including an anode separation plate having a fuel flow path, and installed adjacent to at least one of the unit cells, and communicating with the oxidant flow path or the fuel flow path. And a condensate discharge plate in which a condensate flow path for discharging condensed water condensed in the inlet manifold opening is formed.

The condensate discharge plate may be installed at one or both outermost ends of the unit cells, and the condensate discharge plate may be installed between the unit cells. In addition, a plurality of condensate discharge plates may be installed in the fuel cell at predetermined intervals.

The cathode separator plate, the anode separator plate, and the condensate discharge plate may be provided with an oxidant inlet manifold hole through which an oxidant is distributed, an oxidant outlet manifold hole, a fuel inlet manifold hole through which a fuel is distributed, and a fuel outlet manifold hole. .

The oxidant inlet manifold aperture may be formed to be located above the oxidant outlet manifold aperture in the direction of gravity, and the fuel inlet manifold aperture may be formed above the fuel outlet manifold aperture in the gravity direction.

The condensate flow path may be connected to an oxidant inlet manifold aperture and an oxidant outlet manifold aperture.

In the oxidant inlet manifold hole, the oxidant flow path is connected above in the gravity direction than the condensate flow path, and in the oxidant outlet manifold hole, the oxidant flow path may be connected below in the gravity direction than the condensate flow path. .

The condensate flow path may be connected to a fuel inlet manifold hole and a fuel outlet manifold hole.

At the fuel inlet manifold aperture, the fuel passage may be connected above in the gravity direction than the condensate passage, and at the fuel outlet manifold aperture, the fuel passage may be connected below in the gravity direction than the condensate passage.

The condensate flow path may include a section in which the width gradually decreases as the inlet flows to the outlet.

The condensate flow path may have a structure in which a pressure drop is greater than that of the oxidant flow path and the fuel flow path.

The condensate flow path may be formed at a horizontal or downhill slope.

The condensate flow path may be formed so that the condensate flows in a direction not against gravity.

A porous member may be installed in the condensate flow path.

The unit cells may be stacked in a direction horizontal to the ground.

The unit cells may be stacked in a direction perpendicular to the ground, and in this case, the condensate discharge plate may be installed below the unit cell located at the bottom thereof.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a partial cross-sectional view showing a fuel cell according to a first embodiment of the present invention, Figure 2 is an exploded perspective view showing a fuel cell according to a first embodiment of the present invention.

Referring to the drawings, the fuel cell according to the present embodiment includes a plurality of unit cells 180 including the membrane electrode assembly 100 and the anode separator 120 and the cathode separator 110 on both sides thereof. It is made of a laminated structure repeatedly.

In the following description, a polymer electrolyte fuel cell in which fuel is introduced into the fuel cell in the form of a gas by means of a reformer (not shown) separately installed will be described as an example. However, this is exemplary and the present invention is not limited thereto.

The membrane electrode assembly 100 is composed of a polymer electrolyte membrane 101, an anode electrode 103, and a cathode electrode 102, and a gasket for preventing fuel and oxidant from mixing with each other outside the membrane electrode assembly 100. 104 is installed.

A fuel flow passage 121 for supplying fuel to the anode electrode 103 is formed at one side of the anode separation plate 120. An oxidant flow path 111 for supplying an oxidant to the cathode electrode 102 is formed at one side of the cathode separation plate 110, and a cooling medium flow path 112 is used at the opposite side to cool the reaction heat by the electrochemical reaction. ) Is formed.

The structures of the anode separator 120 and the cathode separator 110 are exemplary, but the present invention is not limited thereto. Therefore, the cooling medium flow path 112 may be formed on the cathode separator plate 110, but may be formed on the anode separator plate 120, or may be simultaneously formed on the cathode separator plate 110 and the anode separator plate 120. have.

An end cathode separator plate 115 is installed in the unit cell 180 provided at the outermost side. The end cathode separator plate 115 is in contact with the membrane electrode assembly 100 and the opposite side of the current collector 131a. 2, the flow path of the cooling medium is not formed. However, the anode separation plate 120 according to the present embodiment has a structure in which a fuel flow passage 121 is formed on one side and a structure in which the flow passage 121 is not provided on the opposite side, and thus the terminal anode separation plate constituting the last unit cell 180. Is made of the same structure as the general anode separator (120).

As illustrated in FIG. 2, current collector plates 131a and 131b for extracting current and insulating plates 132a and 132b for electrical insulation from the outside are sequentially stacked on the outermost sides of the unit cells 180. Fastening plates 133a and 133b are installed in the unit cells 180 to fix the unit cells 180 at a constant pressure. The fastening plates 133a and 133b are tie rods 171 inserted into holes (not shown) formed in the fastening plates 133a and 133b and nuts 172 fastened to ends of the tie rods as shown in FIG. 1. And are fixed through a fastening mechanism such as a leaf spring 173 installed between the nut 172 and the fastening plates 133a and 133b.

In addition, the fastening plate 133a has an oxidant inlet port 134a, a fuel inlet port 135a and a cooling medium inlet port 136a through which fuel gas, an oxidant gas, and a cooling medium are supplied from the outside, and an oxidant outlet from which they are discharged. A port 134b, a fuel outlet port 135b and a cooling medium outlet port 136b are formed.

Meanwhile, the anode separation plate 120 and the cathode separation plate 110 include an oxidant inlet manifold hole 161 and a fuel inlet manifold hole 163 for supplying the introduced fuel gas, the oxidant gas, and the cooling medium to a corresponding flow path. And a cooling medium inlet manifold hole 165, a fuel gas and an oxidant gas discharged from the flow path, an oxidant outlet manifold hole 162 for discharging the cooling medium, and a fuel outlet manifold hole 164 And cooling medium outlet manifold aperture 166.

In addition, the inlet manifold holes 161, 163, and 165 and the outlet manifold holes 162, 164, and 166 are disposed at the same position and have the same shape, and the unit cells 180 are stacked. When arranged, the oxidant inlet manifold holes 161 serve as an oxidant inlet passage for supplying oxidant to the oxidant flow path 111, and the oxidant outlet manifold holes 162 communicate with the oxidant flow path 111 so that It acts as an oxidant discharge passage.

In this manner, the fuel inlet manifold apertures 163 also overlap each other when the unit cells 180 are stacked and communicate with the fuel passage 121 to serve as a fuel inflow passage, and the fuel outlet manifold apertures 164. These are in communication with the fuel flow passage 121 to serve as a fuel discharge passage. In addition, the cooling medium inlet manifold holes 165 are also stacked to abut each other to serve as a cooling medium inlet passage, and the cooling medium outlet manifold holes 166 also serve as a cooling medium discharge passage.

When the unit cells 180 are stacked to form a stack, condensate formed in the oxidant inlet manifold hole 161 and the fuel inlet manifold hole 163 may be discharged at both outermost sides of the stack. The condensate discharge plates 140 and 150 having the condensate flow paths 141 and 151 (shown in FIG. 1) are installed.

The condensate discharge plates 140 and 150 have oxidant inlet manifold holes for supplying the introduced fuel gas, the oxidant gas, and the cooling medium to the corresponding flow paths, such as the anode and cathode separator plates 110 and 120 at both edges thereof. 161, fuel inlet manifold hole 163 and coolant inlet manifold hole 165 and oxidant outlet manifold hole 162 for fuel gas, oxidant gas and cooling medium discharged from the corresponding flow path, fuel outlet manifold Holes 164 and cooling medium outlet manifold holes 166 are formed.

The condensate discharge plates 140 and 150 are connected to the oxidant inlet manifold hole 161 and the oxidant inlet manifold hole 162 to discharge the condensate formed in the oxidant inlet manifold hole 161. The oxidant side condensate discharge plate 140 and the condensate flow path 151 are connected to the fuel inlet manifold hole 163 and the fuel outlet manifold hole 164 to discharge the condensate formed in the fuel inlet manifold hole 163. A fuel side condensate outlet plate 150.

Accordingly, the oxidant side condensate discharge plate 140 and the fuel side condensate discharge plate 150 are disposed at each end of the stack, respectively, so that the condensed water accumulated in the oxidant inlet manifold hole 161 is discharged. Guide condensate accumulated in fuel inlet manifold aperture 163 to fuel outlet manifold aperture 164 to allow condensate to flow into fuel passage 121 or oxidant passage 111. Essentially, it is possible to prevent the blockage of the fuel passage 121 or the oxidant passage 111 or flooding of the electrode.

And the oxidant inlet manifold aperture 161 and the fuel inlet manifold aperture 163 are formed at both upper ends of the anode separator 120, the cathode separator 110 and the condensate outlet plates 140, 150, respectively. The oxidant outlet manifold aperture 162 and the fuel outlet manifold aperture 164 are formed at both lower ends of the anode separator 120, the cathode separator 110, and the condensate outlet plates 140, 150.

Therefore, the inlet manifold holes 161 and 163 are formed higher in the gravity direction than the outlet manifold holes 162 and 164, and oxidant, fuel, and condensate are caused by gravity in the inlet manifold holes 161 and 163. It can be easily moved in the direction of the outlet manifold holes 162 and 164.

As shown in FIG. 3, the oxidant side condensate outlet plate 140 has one side of the condensate outlet plate 140 to direct condensate accumulated in the oxidant inlet manifold aperture 161 to the oxidant outlet manifold aperture 162. A condensate flow path 141 is formed on the surface, and the condensate flow path 141 includes a plurality of flow path channels 142 and ribs 143.

That is, a groove connecting the oxidant inlet manifold hole 161 and the oxidant outlet manifold hole 162 is formed in the surface of the condensate discharge plate 140, and a plurality of ribs 143 are formed in the groove in the longitudinal direction of the groove. Is formed, the groove is formed with a plurality of flow channel (142).

As shown in FIG. 4, the fuel side condensate discharge plate 150 also has a condensate flow path on one side of the condensate discharge plate to guide the condensate accumulated in the fuel inlet manifold hole 163 to the outlet manifold hole 164. A 151 is formed and the condensate flow path 151 is formed through a plurality of flow channel channels 152 and ribs 153.

When the unit cells 180 are stacked in the horizontal direction, the oxidant inlet manifold hole 161 and the fuel inlet manifold hole 163 are each an oxidant outlet manifold hole 162 and a fuel outlet manifold hole. It is formed in the upper direction in the gravity direction than 164, and the oxidant and fuel side condensate flow paths 141 and 151 connect the inlet manifold holes 161 and 163 and the outlet manifold holes 162 and 164, respectively. The condensate flow path is formed so that the discharge direction is from top to bottom.

That is, the condensate flow paths 142 and 152 are formed at a horizontal or downhill slope along the direction in which the condensed water proceeds so that the condensed water naturally proceeds to the outlet manifold holes 162 and 164 by gravity. Therefore, the condensate can naturally proceed to the outlet manifold holes 162 and 164 along the gravity without traveling in the direction against gravity.

5A and 5B, in forming the oxidant inlet manifold hole 161 and the oxidant outlet manifold hole 162, the longitudinal length L1 of the manifold holes 161 and 162 is the total width of the oxidant flow path. It is formed larger than (L2). Similarly, although not shown in the drawing, the longitudinal lengths of the manifold holes 163 and 164 are equal to the total width of the fuel flow paths in the formation of the fuel inlet manifold hole 163 and the fuel outlet manifold hole 164. It is largely formed.

The oxidant flow path 111 of the cathode separator 110 is connected to the upper portion of the oxidant inlet manifold hole 161 in the longitudinal direction and is connected to the lower portion of the oxidant outlet manifold hole 162 in the longitudinal direction.

In addition, the condensate flow path 141 of the cathode side condensate discharge plate 140 is connected to the longitudinal bottom of the oxidant inlet manifold hole 161 and is connected to the longitudinal top of the oxidant outlet manifold hole 162. The fuel flow path 121 of the anode separation plate 120 and the condensate flow path 151 of the anode side condensate discharge plate 150 are also formed in the same structure.

Therefore, the oxidant flow path 111 is located above the condensate flow path 141 in the gravity direction in the oxidant inlet manifold 161, and is located below the condensate flow path 141 in the outlet manifold 162. do. In addition, the fuel passage 121 is positioned above the condensate passage 151 in the direction of gravity in the fuel inlet manifold 163 and lower in the gravity direction than the condensate passage 151 in the fuel outlet manifold 164. Done.

In this structure, the water condensed in the oxidant or fuel inlet manifold holes 161 and 163 is heavy and accumulates at the lower end of the manifold holes 161 and 163. The fuel and oxidant are light and circulated upwards. Since the fuel passages 111 and 121 are connected to the manifold holes 161 and 163, the condensed water may be prevented from flowing into the oxidant or the fuel passages 111 and 121.

Furthermore, the condensate flow paths 141 and 151 are connected to the lower ends of the manifold holes 161 and 163 so that the accumulated condensate is led to the outlet manifold holes 162 and 164 through the condensate flow paths 141 and 151, thereby condensed water inherently. It can block the flow into the flow path.

6 is a cross-sectional view illustrating a fuel cell according to a second embodiment of the present invention.

The condensate discharge plate may be disposed at both edges of the stacked unit cell stacks as shown in FIG. 1, but a plurality of condensate discharge plates may be disposed at predetermined intervals in the unit cell stack as shown in FIG. 6.

6, the oxidant side condensate discharge plate 140 is first disposed after the current collector plate 131a, followed by the termination cathode separator 115, the membrane electrode assembly 100, the anode separator 120, and the fuel side. The condensate discharge plate 150 is disposed. Subsequently, the cathode separation plate 110, the membrane electrode assembly 100, and the anode separation plate 120 are disposed for a predetermined period, and the oxidant side condensate discharge plate 140 is next disposed. Subsequently, the cathode separation plate 110, the membrane electrode assembly 100, and the anode separation plate 120 are disposed for a predetermined period, and the fuel side condensate discharge plate 150 is next disposed. After laminating periodically in this manner, the fuel-side condensate discharge plate 150 is placed in contact with the current collector plate 131b. Through the above-described periodic arrangement method, the condensed water accumulated in the inlet manifold holes 161 and 163 can be discharged to the outlet manifold holes 162 and 164 more smoothly.

7 is a front view showing a condensate discharge plate according to a third embodiment of the present invention.

In the condensate discharge plate 240 according to the present embodiment, a condensate flow path 241 is formed such that a pressure drop largely occurs along the direction in which the condensate proceeds. That is, the condensate flow path 241 is formed with a relatively small cross-sectional area, the flow path is formed in a zigzag form across the condensate discharge plate a plurality of times to form a relatively long length of the flow path.

It is most preferable that only the condensate is discharged through the flow path 241 of the condensate discharge plate 240, but a part of the reaction gas may be mixed with the condensate and discharged together. When the amount of the reaction gas discharged to the outlet manifold without participating in the reaction through the condensate discharge plate 240 is large, the power loss increases and the efficiency decreases because the flow rate of the reaction gas must be increased.

However, when the cross-sectional area of the condensate flow path 241 is made small and the length of the flow path 241 is formed as in the present embodiment, a pressure drop occurs largely so that the reaction gas does not flow into the condensate flow path.

At this time, the amount of pressure drop is more preferably greater than the pressure drop of the oxidant flow path of the cathode separation plate. By doing so, it is possible to selectively discharge only the condensate while greatly reducing the amount of reaction gas discharged through the condensate flow path 241.

8 is a front view showing a condensate discharge plate according to a fourth embodiment of the present invention.

The condensate discharge plate 340 according to the present embodiment is connected to the inlet manifold hole and the outlet manifold hole by a condensate flow path formed in a straight line shape. In this case, the width of the flow path 341 may be formed to become narrower toward the exit direction. As the width of the flow path 341 is gradually narrowed along the traveling direction, the ability to guide the condensate to the outlet is further accelerated by the capillary pressure as well as gravity.

9 is a front view showing a condensate discharge plate according to a fifth embodiment of the present invention.

Condensate discharge plate 440 according to the present embodiment is inserted into the wick or porous material 442 that can promote the capillary action inside the condensate flow path (441). In this case too, the ability to direct condensate to the outlet is further accelerated by capillary pressure as well as gravity. In addition, the porous material inserted into the flow path serves as a resistance to the flow of the reaction gas to prevent the reaction gas from bypassing through the condensate flow path can be more effectively achieved.

10 is an exploded perspective view illustrating a fuel cell according to a sixth embodiment of the present invention.

The fuel cell according to the present exemplary embodiment has a structure in which unit cells are stacked in a vertical direction with respect to the ground. The membrane electrode assembly 500 and the unit cells composed of the cathode separator 510 and the anode separator 520 are sequentially stacked on both sides thereof are the same as in the first embodiment of the present invention, except that the stacking direction is relative to the ground. It is made in the direction perpendicular to the ground, such as gravity, not horizontal.

At this time, the condensate discharge plate (540, 550) is installed in the lower portion than the unit cell in order to facilitate the discharge of the condensate in the inlet manifold hole. That is, the fastening plate 533b is positioned at the bottom end, and the insulating plate 532b and the current collecting plate 531b are sequentially disposed thereon, and then the anode side condensate discharge plate 550 and the cathode side condensate discharge plate 540 are disposed. The unit cells are stacked thereon.

However, the stacking order of the anode side condensate discharge plate 550 and the cathode side condensate discharge plate 540 is not limited.

The reaction gas and the cooling medium are introduced into the stack through the oxidant inlet port 534a, the fuel inlet port 535a and the cooling medium inlet port 536a, respectively, attached to the fastening plate 533a located at the top of the fuel cell. It is discharged to the outside through the oxidant outlet port 534b, the fuel outlet port 535b and the cooling medium outlet port 536b attached to the fastening plate 533b located at the bottom.

Water condensed in the oxidant inlet manifold or fuel inlet manifold through the above-described configuration is accumulated at the lower end of the stack by gravity, and the oxidant outlet manifold or fuel outlet manifold through the condensate outlet plates 540 and 550 installed at the bottom end. It is induced to be discharged to the outside.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

As described above, according to the present invention, a condensate discharge plate is formed inside the fuel cell to guide the condensate generated in the inlet pipe and the inlet manifold to the outlet manifold so that the condensate flows into the oxidant or the fuel flow path and blocks the flow channel. Flooding phenomenon can be easily prevented.

In addition, the condensate flow path in the inlet manifold can be connected below the fuel and oxidant flow path to prevent condensate from entering the fuel and oxidant flow path.

In addition, the condensate flow path formed in the condensate discharge plate is formed so that the condensate is discharged in a direction not against gravity can easily discharge the condensate formed in the inlet manifold to the outlet manifold.

In addition, the condensate flow path is formed in a structure in which a pressure drop is greatly increased as it proceeds downstream, it is possible to easily prevent the oxidant or fuel flow through the condensate flow path.

Claims (18)

A membrane electrode assembly comprising a polymer electrolyte membrane and an electrode; A cathode separator disposed adjacent to one side of the membrane electrode assembly and in which an oxidant flow path is formed; A plurality of unit cells each including; an anode separation plate disposed adjacent to the other side of the membrane electrode assembly and having a fuel flow path formed therein; And A condensate discharge plate disposed adjacent to at least one of the unit cells and having a condensate flow path configured to discharge condensed water condensed at an inlet manifold hole communicating with the oxidant flow path or the fuel flow path; Fuel cell comprising a. The method of claim 1, The condensate discharge plate is installed to be adjacent to the outermost one or both ends of the unit cells. The method of claim 1, The condensate discharge plate is installed between at least one pair of adjacent unit cells. The method of claim 1, The plurality of unit cells are stacked to form a stack structure, wherein the condensate discharge plate is spaced apart in the stack structure spaced apart a plurality of fuel cells. The method of claim 1, The cathode separator plate, the anode separator plate, and the condensate discharge plate include an oxidant inlet manifold hole and an oxidant outlet manifold hole through which an oxidant is distributed, and a fuel inlet manifold hole and a fuel outlet manifold hole through which fuel is distributed. battery. The method of claim 5, And the oxidant inlet manifold aperture is formed so as to be located above the oxidant outlet manifold aperture in the direction of gravity and the fuel inlet manifold aperture is formed so as to be located above the fuel outlet manifold aperture in the gravity direction. The method of claim 5, And the condensate flow path of the condensate discharge plate is connected to the oxidant inlet manifold aperture and the oxidant outlet manifold aperture. The method of claim 7, wherein At the oxidant inlet manifold aperture, the oxidant passage is connected above in the gravity direction than the condensate passage, and at the oxidant outlet manifold aperture, the oxidizer passage is connected below in the gravity direction than the condensate passage. The method of claim 5, The condensate flow path of the condensate discharge plate is connected to the fuel inlet manifold aperture and the fuel outlet manifold aperture. The method of claim 9, At the fuel inlet manifold aperture, the fuel passage is connected above in the gravity direction than the condensate passage, and at the fuel outlet manifold aperture, the fuel passage is connected below in the gravity direction than the condensate passage. The method of claim 1, The condensate flow path of the condensate discharge plate comprises a section in which the width gradually decreases along the progress direction of the condensate. The method of claim 1, And the condensate flow path has a larger pressure drop than the oxidant flow path and the fuel flow path. The method of claim 1, The condensate flow path of the condensate discharge plate is formed in a horizontal or downhill slope. The method of claim 1, And the condensate flow path of the condensate discharge plate is formed such that the condensate flows in a direction not against gravity. The method of claim 1, And a porous member in the condensate flow path of the condensate discharge plate. The method of claim 1, The unit cell is a fuel cell stacked in a direction horizontal to the ground. The method of claim 1, The unit cell is stacked in a direction perpendicular to the ground. The method of claim 17, The condensate discharge plate is installed under the unit cell located at the bottom of the fuel cell.

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