KR20140075249A - Fuel Mixing tank with Preventing Device of Fuel Surging for Direct Methanol Fuel Cell System And Direct Methanol Fuel Cell System Comprising The Same - Google Patents

Abstract

The present invention relates to a fuel mixing tank for a direct methanol fuel cell system having a fuel flow preventing device installed thereon and a direct methanol fuel cell system including the same. The fuel mixing tank of the present invention receives raw liquid methanol fuel, cathode discharged material, and anode discharged material respectively from a fuel tank, a cathode, and an anode and provides the anode with mixed fuel that is made by mixing the same. The fuel mixing tank comprises a top chamber and a bottom chamber that are separated into a top and a bottom by means of a separation plate. The top chamber comprises: a cathode discharged material inlet through which the cathode discharged material is supplied; and a gas outlet through which gas is discharged to the outside. The bottom chamber comprises: an anode discharged material inlet through which the anode discharged material is supplied; a raw liquid methanol inlet through which the raw liquid methanol fuel is supplied from the fuel tank; and a fuel supply hole through which the mixed fuel is supplied to the anode. The separation plate comprises: a water supply channel that is installed as a pipe for penetrating through the separation plate in order to have the top disposed in the top chamber and the bottom disposed in the bottom chamber; and a gas transferring unit for transferring the gas in the bottom chamber to the top chamber, wherein a flow preventing plate is installed inside the bottom chamber and has a moving hole so that the mixed fuel can be moved up and down.

Description

TECHNICAL FIELD [0001] The present invention relates to a fuel tank for a direct methanol fuel cell system equipped with a fuel flow prevention device, and a direct methanol fuel cell system including the methanol fuel cell. }

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel tank for a direct methanol fuel cell system equipped with a fuel flow prevention device and a direct methanol fuel cell system including the fuel tank, A fuel mixing tank for a direct methanol fuel cell system in which a flow preventing plate having a moving hole serving as a fuel flow preventing device is provided in order to prevent residual methanol and generated water in a fuel mixing tank having a fuel tank ≪ / RTI >

Fuel cells are electrochemical generation systems that directly convert chemical energy contained in hydrocarbon fuels such as gaseous hydrogen and natural gas or liquid methanol and ethanol into electrical energy.

Such a fuel cell power generation system is a clean power generation system that can replace an internal combustion engine generator using fossil energy. The fuel cell power generation system is composed of stacked stacked unit cells, and can output a wide range of output. And it is attracting attention as a compact and portable portable power source because it shows the energy density of ship.

Typical examples of the low temperature type fuel cell include a polymer electrolyte membrane fuel cell (PEMFC) and a direct methanol fuel cell (DMFC).

Direct methanol fuel cell uses methanol, which is liquid, directly as fuel, so it can be applied to portable and mobile fuel cell power generation because of advantages such as storage and transportation of liquid fuel, simple system construction without need of reformer or humidifier, and operation at room temperature .

As shown in FIG. 1, the direct methanol fuel cell system is composed of a stack (MEA, separator, gasket, end plate, etc.) as well as a fuel supply unit, an air supply unit, It becomes a module that can supply actual power only if it is a rather complicated system.

The electrochemical reactions occurring at the electrodes inside the direct methanol fuel cell stack are as follows. In the anode reaction, carbon dioxide, hydrogen cations (protons) and electrons are generated by the catalytic oxidation reaction of methanol and water, and oxygen in the air is reduced by the cathode reaction, and water is generated by reacting with the hydrogen ions migrating from the anode. In the whole reaction, methanol and oxygen react with each other to produce water and carbon dioxide, and electrons move through an external circuit to obtain electricity.

_{CH 3 OH + H 2 O →} CO 2 + 6H + + 6e-

^{_{3 / 2O 2 + 6H + +}} 6e- → 3H 2 O

CH ₃ OH + 3 / 2O ₂ ? 3H ₂ O + CO ₂ (E = 1.21 V)

In the actual fuel cell electrode reaction, the methanol permeability of the cation conductive membrane used as the electrolyte is too high, so that the methanol concentration of the fuel used in the fuel electrode should be adjusted to about 2-5 wt%. That is, when the concentration of methanol in the fuel is too high, the amount of methanol permeated to the air electrode becomes large, and these methanol burns in the air electrode, resulting in a large amount of heat and methanol efficiency reduction. In order to supply 2-5 wt% of fuel to the stack, a fuel mixing tank, a gas-liquid separator and a crude methanol tank are required. Of these, the fuel mixture tank and the gas-liquid separator take the largest volume, They may be interconnected and integrated.

When the direct methanol fuel cell system is operated for the first time, pure methanol is supplied from the methanol tank to the fuel mixing tank in order to adjust the concentration to 2-5 wt% by using the water previously supplied to the fuel mixing tank, When the specified concentration is reached, the fuel is supplied to the stack by the fuel supply pump. After this operation, the concentration is adjusted to a predetermined concentration by using the unreacted material of the fuel electrode and the produced water generated in the air electrode. After starting the system for the first time, the fuel solution of the fuel electrode is continuously circulated, and the deficient water adopts a method of using generated water produced in the air electrode.

When the fuel solution of the fuel electrode is continuously circulated by the evaporation of the reactant due to the temperature of the stack and the water crossover (permeation) from the fuel electrode to the air electrode, water shortage occurs ultimately. Therefore, It is necessary to additionally provide an air and water condenser and a gas-liquid separator on the air electrode side in order to supply the air to the anode as much as necessary.

In the fuel supply system, the circulation of generated water, the rational design of concentration / water level control, the water management control and the operation technique are one of the most important parts for the long-term operation and durability of the direct methanol fuel cell system.

When operating a direct methanol fuel cell system, the theoretically calculated flow rate (assuming that all of the electrical charge is completely oxidized by the feed methanol at the anode) is as follows. Using the Faraday's law, the required amount of methanol and air, the amount of carbon dioxide produced and the amount of generated water can be calculated in a steady state (room temperature (298K), 1 atm) according to the electrochemical equation. When the stored electricity quantity, that is the passage of 96,500C 1F E 1mol (e-), i.e., 6 x 10 ²³ electrons are moved so = 6 x 10 charge having a dog e 1 (e = (96500C) / (6 x 10 23) - ¹⁹ C) is calculated, and if the electric current (1 C) when the current of 1 A flows for 1 second is calculated according to the number of electrons (N _e = 6 _e- ) generated by methanol oxidation in the electrochemical reaction formula, The amount of methanol required is N _MeOH = (5.54 x 10 ^-8 ) / (0.788) = 7.03 x 10 ^-8 L / sec.

When 1 mol of methanol is consumed at the anode by the whole electrochemical reaction formula, 1.5 mol (48 g) of oxygen is needed. Thus 1A the amount of oxygen required for the load current ^{_{N O2 = 8.3x10 -8 kg / sec}} = (22.4L x 8.3 x 10 -8 kg / sec) / (32 x 10 -3 kg) = 5.81 x 10 -5 L / sec. Since the ratio of oxygen in the atmosphere is about 21%, the amount of air to be supplied is N _air = (5.81 x 10 ^-5 ) / (0.21) = 2.77 x 10 ^-4 L / sec.

When 1 mole of methanol is consumed, 1 mole (44 g) of carbon dioxide is produced. The amount of methanol consumed at a load current of 1 A is 1.73 x 10 ^-6 mol / sec, so the amount of carbon dioxide produced is N _{CO 2} = (1.73 x 10 ^-6 mol / sec) x (22.4 L / mol) = 3.87 x 10 ^-5 L / sec.

When methanol is consumed at 1 mol, 2 mol (36 g) of water is produced, and the amount of produced water at a load current of 1 A is N _H2O = (1.73 x 10 ^-6 k) x (36 x 10 ^-3 ) kg / mol = 6.23 x 10 ^-8 L / sec. The amount of generated water considering the density of water is N _H2O = (6.23 x 10 ^-8 kg / sec) x (1 L / kg) = 6.23 x 10 ^-8 L / sec.

The utilization rate of methanol is an important factor that determines the performance of the fuel cell. This is because it determines how much of the fuel and air supplied is involved in the electrochemical reaction. The fuel utilization rate is the ratio of the amount of electricity observed as the ratio of supplied fuel to the fuel used for power generation, and the theoretical output of the fuel cell, that is, the methanol utilization rate = (observed electricity quantity) / (theoretical output of the equivalent methanol). It is generally reported that the utilization of methanol is about 60%. Assuming that the product is taken as 1, the reactant should be supplied as 1 / 0.6 = 1.67. Therefore, the amount of methanol to be fed is F _{O MeOH} = 1.67 x 7.03 x 10 ^-8 L / sec = 1.17 x 10 ^-7 L / sec and the amount of oxygen to be fed is F _O2 = 5.81 x 10 ^-5 x 1.66 = 9.64 x 10 ^-5 L / sec, and the amount of air to be supplied is F _Air = 1.66 x 2.77 x 10 ^-4 L / sec = 4.02 x 10 ^-4 L / sec. At this time, the amount of water produced is P _H2O = 6.23 x 10 ^-8 L / sec and the amount of generated carbon dioxide is P _CO2 = 3.87 x 10 ^-5 L / sec.

The decrease in methanol utilization in the direct methanol fuel cell system is due to the methanol crossover and the loss of unreacted methanol, which is very important for determining the performance and efficiency of the direct methanol fuel cell. That is, it is necessary to use the supplied methanol as much as possible to lower the loss, which can be enhanced by using an electrolyte membrane having little methanol permeation on the stack or by designing and applying a highly efficient gas-liquid separator (fuel mixing tank).

The present invention can simplify the structure of the system by simultaneously performing the mixing function of fuel, the gas-liquid separation of the fuel electrode, and the gas-liquid separation function of the air electrode as one apparatus, and the gas- And to provide a direct methanol fuel cell system including the same, which can minimize the loss of methanol discharged together with the direct methanol fuel cell system.

Further, it is possible to minimize the flow of the mixed fuel even when vibration or shock is applied during the movement, thereby preventing the mixing fuel from being swayed up or down or from side to side. Thus, the fuel tank of the direct methanol fuel cell system having excellent stability and the direct methanol fuel Battery system is provided.

The present invention relates to a fuel tank for a direct methanol fuel cell system in which a fuel tank, an air electrode, and a fuel electrode respectively receive a raw liquid methanol fuel, a cathode effluent and an anode effluent and supply the mixed fuel produced by mixing them to the fuel electrode, Wherein the anode includes a cathode outlet and an anode outlet through which the cathode outlet is supplied and a gas outlet that discharges gas to the outside, And a fuel supply port for supplying the mixed fuel to the fuel electrode, wherein the separator plate is a tube that penetrates the separator plate, and the upper portion is a portion And the lower part is disposed in the upper part And a gas transfer portion for allowing the gas to be delivered to the fuel chamber to be transferred to the fuel chamber is formed on the inner surface of the cylinder, and a flow preventing plate having a moving hole for moving the fuel mixture vertically is formed on the inner side of the cylinder. Thereby providing a fuel mixing tank of the battery system.

The flow prevention plate is preferably formed to have a lower level than the normal level of the mixed fuel.

The flow prevention plate is preferably made of metal or plastic having resistance to methanol. Examples of the flow prevention plate include corrosion resistant stainless steel (STS), polypropylene (PP), polyethylene (PE), or polycarbonate have.

The sum of the areas of the moving holes is preferably 1/2 to 1/20 of the flow-restricting plate area.

The gas outlet is preferably formed of a porous hydrophobic separation membrane.

The porous hydrophobic separation membrane may comprise polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF).

The pore size of the porous hydrophobic separation membrane is preferably 0.001 to 0.05 mm.

The thickness of the porous hydrophobic separation membrane is preferably 0.01 to 0.1 mm.

The fuel mixture tank of the direct methanol fuel cell system includes two or more level sensors for measuring the level of the water to detect the water level so that the water level of the fuel is maintained lower than the fuel electrode effluent inlet .

It is preferable that the ratio of the level of the loss to the level of the above-mentioned level is 1/10 to 1/3.

The cross-sectional area of the water supply channel is preferably 4 to 30 times the area of the gas delivery portion.

The area of the gas delivery portion is preferably 0.5 to 15 mm ² .

The cross-sectional area of the water supply channel is preferably equal to or less than 1/5 of the area of the separation plate.

It is preferable to further include a concentration measuring sensor for measuring the concentration of methanol in the sample.

At least two flow prevention plates may be provided. At this time, it is preferable that one of the flow prevention plates is formed to be higher than the normal level of the mixed fuel.

The present invention provides a direct methanol fuel cell system comprising the fuel mixing tank.

The fuel tank of the direct methanol fuel cell system of the present invention and the direct methanol fuel cell system including the fuel tank of the direct methanol fuel cell system of the present invention minimize the flow of the mixed fuel even when vibration or impact is applied during movement, Stability.

Also, as a single device, it is possible to simultaneously perform a mixing function of fuel, a gas-liquid separation of a fuel electrode, and a gas-liquid separation function of an air electrode, thereby simplifying the configuration of the system. Thereby minimizing the loss of methanol discharged together.

1 is a diagram showing a configuration of a conventional direct methanol fuel cell system.
2 is a schematic diagram illustrating a configuration of a direct methanol fuel cell system according to an embodiment of the present invention.
FIG. 3 is a schematic view of a fuel mixing tank of a direct methanol fuel cell system according to an embodiment of the present invention. Referring to FIG.
4 is a view showing the structure of a separator according to an embodiment of the present invention.
5 is a view showing the structure of a flow-preventive plate according to an embodiment of the present invention.
FIG. 6 is a schematic view showing a configuration of a fuel mixing tank of a direct methanol fuel cell system according to an embodiment of the present invention.
7 is a schematic view showing the configuration of a fuel mixing tank of a direct methanol fuel cell system according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the embodiments according to the present invention, detailed description of known configurations or functions will be omitted. In addition, in adding the reference numerals to the constituent elements of the drawings, the same constituent elements are denoted by the same reference symbols as possible.

The terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary meanings and should be construed in accordance with the technical meanings and concepts of the present invention.

The embodiments described in the present specification and the configurations shown in the drawings are preferred embodiments of the present invention and are not intended to represent all of the technical ideas of the present invention and thus various equivalents and modifications Can be.

2 is a schematic diagram illustrating a configuration of a direct methanol fuel cell system according to an embodiment of the present invention.

Referring to FIG. 2, a direct methanol fuel cell system according to an embodiment of the present invention includes a stack 10, a fuel tank 30, a fuel mixing tank 20, and oxygen supply units 60 and 61.

The stack 10 includes one or more stacked membrane electrode assemblies, which are supplied with fuel from the fuel mixing tank 20 and supplied with oxygen from the oxygen supply unit to produce electricity.

The fuel mixing tank 20 receives methanol fuel from the fuel tank 30, receives unreacted methanol and water discharged from the fuel electrode of the stack 10, and water discharged from the air electrode, and mixes them. Methanol mixed fuel to the fuel electrode.

The water tank 40 stores water that has passed through the polymer electrolyte membrane to the air electrode and water that is generated from the air electrode. Since the cathode exhaust gas discharged from the cathode has a large amount of water discharged in a gaseous state, it may be subjected to a liquefaction process using a condenser. The water in the water tank 40 is supplied to the fuel mixing tank 20 through the pump 63.

The fuel tank 30 stores the methanol fuel solution. As described above, since the reaction in the fuel electrode is used not only methanol but also water as a reactant, the fuel is mixed with water in the fuel mixing tank 20, . The fuel in the fuel tank 30 is supplied to the fuel mixing tank 20 through the pump 64. [

The oxygen supply units 60 and 61 are parts for supplying oxygen used as an oxidant to the air electrode in the reaction of the air electrode, and are composed of an air filter 70 and a pump 61. Although the structure using air is exemplified in this embodiment, it is also possible to supply oxygen itself, and in this case, the air filter 70 is not used.

On the other hand, since the fuel electrode exhaust discharged from the fuel electrode is raised to a high temperature due to the heat of reaction at the fuel electrode, the temperature of the fuel electrode exhaust can be cooled to an appropriate level by using the heat exchanger (50).

A notable part of the present invention is a gas-liquid separator used for the reuse of fuel and water. The fuel, which is the fuel, is also evaporated through the gas-liquid separator for discharging the gaseous carbon dioxide generated by the methanol oxidation reaction in the stack 10, thereby consuming methanol unnecessarily. This leads to a decrease in efficiency of methanol use, that is, a decrease in system efficiency.

According to the direct methanol fuel cell system of the present invention, by designing the fuel mixing tank 20 that integrates the gas-liquid separation of the anode effluent, the gas-liquid separation of the cathode exhaust, and the fuel mixing function, the complex structure of the system is simplified, Thereby minimizing the loss of methanol. In addition, when vibration or shock is applied when the system is moved, the flow of the mixed fuel is prevented, and thus, the system has excellent stability.

Hereinafter, the fuel mixing tank 20 of the direct methanol fuel cell of the present invention will be described in more detail with reference to FIGS. 3 and 4. FIG. FIG. 3 is a schematic view showing the construction of a fuel mixing tank 20 of a direct methanol fuel cell system according to an embodiment of the present invention, and FIG. 4 is a schematic view showing the structure of a direct methanol fuel cell system according to an embodiment of the present invention. FIG. 2 is a view showing a structure of a separator plate 120 included in the mixing tank 20; FIG.

Referring to FIGS. 3 and 4, the fuel mixing tank 20 according to an embodiment of the present invention includes a loss chamber 230 and a freezing chamber 210 separated by a separation plate 220.

The cathode 230 has a cathode outlet 231 through which a cathode discharge discharged from the cathode is supplied and a cathode outlet 232 through which a gas is discharged to the outside. There are formed a fuel electrode outlet 213, a raw liquid methanol inlet 211 for supplying methanol fuel from the fuel tank 30, and a fuel supply port 212 for supplying mixed fuel to the fuel electrode. In addition, a flow preventing plate 260 having a moving hole 261 is formed on the inner side of the freezing face so that the mixed fuel can be moved up and down.

A water supply channel 240 is formed in the separating plate 220 separating the fuel mixing tank 20 into the upper chamber 230 and the lower chamber 210. The water supply channel 240 penetrates the separating plate 220 The upper portion is disposed in the upper chamber 230 of the fuel mixing tank 20 and the lower portion is disposed in the lower chamber 210 of the fuel mixing tank 20.

The gas distribution unit 250 is a passage through which the gas such as carbon dioxide, which is filled in the chamber 210, is transferred to the chamber 230. The gas transmission part 250 may be formed by bored one or more than two holes in the separating plate 220.

The fuel mixing tank 20 further includes a level sensor (not shown) for measuring the level of water 210 to be maintained at a level lower than the fuel electrode discharge inlet 213 and higher than the fuel supply port 210 Or more.

The concentration sensor 270 may further include a concentration measuring sensor 270 for measuring the concentration of methanol. When the concentration of methanol in the concentration measuring sensor 270 is less than a suitable range, the methanol is supplied from the fuel tank 30.

5 is a view showing the structure of a flow-preventive plate 260 according to an embodiment of the present invention.

The flow prevention plate 260 is formed on the inner side of the freezing plate 260 so as to have a moving hole 261 so that the mixed fuel can move up and down. When the fuel mixing tank 20 receives vibrations or external shocks through the structure, the mixed fuel can move up and down and right and left through the moving holes 261. However, Can be prevented. The sum of the areas of the moving holes 261 is preferably 1/2 to 1/20 of the area of the flow preventing plate 260. When the lower limit is not satisfied, the moving holes 261 are small, The mixing fuel is excessively moved up and down. When the upper limit is exceeded, the size of the moving hole 261 is increased, so that the mixed fuel moves too freely through the moving hole 261 So that the object of flow prevention can not be sufficiently attained, which is not preferable.

(STS), polypropylene (PP), polyethylene (PE), or polycarbonate (PC), for example, may be used as the flow prevention plate 260. The flow prevention plate 260 is preferably made of metal or plastic having resistance to methanol. .

The flow prevention plate 260 is formed with a water supply channel penetration portion 262 through which the water supply channel 240 can be formed.

One or more of the flow prevention plates 260 may be installed, and it is preferable that the flow prevention plate 260 is formed to be lower than the normal level of the mixed fuel. However, when two or more flow prevention plates 260 are installed, some of them may be formed higher than the normal water level. Here, "normal water level" refers to the average level of the mixed fuel in the fuel tank during operation of the fuel cell.

6, three flow-restricting plates 261, 262, and 263 are provided. The two flow-restricting plates 261 and 262 are disposed below the normal water level of the mixed fuel, Shows that it is higher than that.

On the other hand, the flow prevention plates 260, 261, 262, and 263 are not necessarily provided so as to be in contact with the inner wall of the mouth, but may be disposed side by side. The flow of the mixed fuel can be made more freely to the side where the flow-preventing plates 260, 261, 262, 263 are not formed. When a plurality of flow prevention plates 261, 262 and 263 are provided, as shown in FIG. 7, the regions where the flow prevention plates 261, 262 and 263 are not formed are staggered to prevent a large flow of the fuel mixture, You can make it happen.

The detailed structure of the fuel mixing tank 20 is preferably such that the ratio of the water level of the waste water 230 to the water level of the water tank 210 is maintained at 1/10 to 1/3. In addition, the cross-sectional area of the water supply channel 240 is preferably 1/5 or less of the area of the separator plate 220. When the gas delivery portion 250 is formed by piercing the separation plate 220, the area of the gas delivery portion 250 is preferably 0.5 to 15 mm ^{2. In} this case, the cross-sectional area of the water supply channel 240 Is preferably 4 to 30 times the area of the gas delivery portion 250.

The gas outlet is an outlet through which unreacted air, which is a cathode electrode discharge, and generated carbon dioxide, which is an anode electrode discharge, are discharged outside the fuel cell system. Therefore, the gas outlet should be designed so that only unreacted air and generated carbon dioxide are discharged, and generated water, unreacted methanol and water are not discharged. In order to achieve this purpose, it is possible to prevent water shortage or methanol loss by designing the gas outlet to pass only unreacted air and generated carbon dioxide, and not through methanol or water.

In order to achieve the above object, it is possible to install a porous hydrophobic separation membrane at the gas outlet so that only a gas such as unreacted air or generated carbon dioxide can pass without passing through a liquid such as methanol or water. For this purpose, a hydrophobic membrane such as polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF) may be used as the porous hydrophobic separation membrane. These membranes are porous, 0.001-0.05 mm, and a thickness of 0.01-0.1 mm may be used. Further, in order to impart mechanical strength to these films, a support film having pores larger than pores of the film can be provided on the upper and lower surfaces of the film.

If the pore size of the porous hydrophobic membrane is too large, a liquid such as methanol or water may pass through and be discharged to the outside. If the pore size is too small, it is difficult to pass methanol or water. Therefore, the pore size of the porous hydrophobic membrane is preferably 0.001-0.05 mm, and preferably 0.01-0.03 mm. The porous hydrophobic membrane is preferably hydrophobic, not hydrophilic, in order to prevent clogging of pores by water or methanol.

Hereinafter, a process of supplying methanol fuel, anode discharge, and cathode discharge through a fuel mixing tank 20 of a direct methanol fuel cell system according to an embodiment of the present invention to a fuel electrode will be described in detail.

First, the cathode exhaust discharged from the cathode is supplied through the anode outlet 231 of the cathode 230. The cathode effluent includes water generated from the cathode, water and methanol crossovered to the cathode through the electrolyte membrane, and air supplied for the reduction reaction.

Also, the fuel electrode discharge discharged from the fuel electrode is supplied through the fuel electrode discharge inlet 213 of the discharge electrode 210. The anode effluent includes methanol and water supplied to the anode, and carbon dioxide produced through the oxidation reaction.

At the same time, the methanol fuel stock solution is supplied from the fuel tank 30 through the undiluted methanol inlet 211 of the fuel tank 30.

When the anode effluent and the methanol fuel are supplied to the anode 210, the lower portion of anode 210 is filled with methanol and water, and the upper portion is filled with gas including carbon dioxide. These gases are discharged to the chamber 230 through the gas delivery part 250 due to an increase in the pressure inside the chamber 210 while the anode effluent and the methanol fuel are continuously supplied to the chamber 210.

At this time, not only carbon dioxide but also vaporized methanol is contained in the exhaust gas, and the exhaust gas is transferred to the loss chamber 230 through the gas transmission part 250 and is collected in the water filled in the loss chamber 230.

When the height of the water supply channel 240 is higher than the height of the upper end of the water supply channel 240 as the water level increases, water is overflowed into the water supply channel 240, The water is supplied to the user (210).

The air supplied through the carbon dioxide and air electrode discharge inlet 231 discharged from the gas delivery portion 250 through the discharge port 230 is filled in the upper portion of the chamber 230 and discharged to the outside through the gas discharge port 232.

 The diluted methanol, that is, the mixed fuel filled in the fuel tank 210 is supplied to the fuel electrode through the fuel supply port 212 by using the pump 62.

Through this circulation process, water can be continuously reused, carbon dioxide can be prevented from flowing into the fuel supplied to the fuel electrode, and the loss of methanol discharged to the outside in a vaporized state can be minimized.

Description of the Related Art [0002]
10: stack 20: fuel mixing tank
30: Fuel tank 40: Water tank
50: heat exchanger 61, 62, 63, 64: pump
70: air filter 210: your way
211: undiluted methanol inlet 212: fuel inlet
213: anode effluent inlet 220: separator plate
230: loss 231: cathode effluent inlet
232: gas outlet 240: water supply channel
250: gas delivery portion 260: flow prevention plate
261: moving hole 262: water supply channel penetration part
270: fuel concentration measurement sensor

Claims (18)

1. A fuel tank for a direct methanol fuel cell system in which a fuel tank, an air electrode, and a fuel electrode respectively receive undiluted methanol fuel, a cathode effluent, and an anode effluent,
A loss and a loss separated upwardly and downwardly by the separating plate,
And a gas outlet for discharging the gas to the outside is formed in the discharge space,
Wherein the fuel electrode outlet is provided with the fuel electrode discharge inlet, the raw liquid methanol inlet from which the raw methanol fuel is supplied from the fuel tank, and the fuel supply port that supplies the mixed fuel to the fuel electrode,
Wherein the separating plate is a tube penetrating the separating plate, the upper portion being disposed in the upper chamber, the lower portion being a water supply channel disposed in the lower portion, and a gas delivery portion for allowing the gas in the lower portion to be transferred to the lower chamber,
And a flow preventive plate having a moving hole is formed on the inner side of the hollow body so that the mixed fuel can move up and down.
The method according to claim 1,
Wherein the flow prevention plate is formed to be lower than a normal water level of the mixed fuel.
The method according to claim 1,
Wherein the flow preventer plate is formed of a corrosion resistant stainless steel (STS), polypropylene (PP), polyethylene (PE), or polycarbonate (PC).
The method according to claim 1,
And the sum of the areas of the moving holes is 1/2 to 1/20 of the area of the flow-restricting plate.
The method according to claim 1,
Wherein the gas outlet is formed of a porous hydrophobic separation membrane.
6. The method of claim 5,
Wherein the porous hydrophobic separation membrane comprises polytetrafluoroethylene (PTFE), ethylene tetrafluoroethylene (ETFE), or polyvinylidene fluoride (PVDF).
6. The method of claim 5,
Wherein the pore size of the porous hydrophobic separation membrane is 0.001-0.05 mm.
6. The method of claim 5,
Wherein the porous hydrophobic separation membrane has a thickness of 0.01 to 0.1 mm.
The method according to claim 1,
Further comprising a level sensor for measuring the level of the water to detect the water level so that the water level of the water level is kept lower than the inlet of the anode effluent and is maintained higher than the fuel supply unit, .
The method according to claim 1,
Wherein the ratio of the level of the liquid to the level of the liquid is 1/10 to 1/3.
The method according to claim 1,
Wherein the cross-sectional area of the water supply channel is 4 to 30 times the area of the gas delivery portion.
The method according to claim 1,
Wherein the area of the gas delivery portion is 0.5 to 15 mm < ^{2 &} gt ;.
The method according to claim 1,
Wherein the cross-sectional area of the water supply channel is 1/5 or less of the area of the separation plate.
The method according to claim 1,
Further comprising a concentration measuring sensor for measuring the concentration of methanol in the fuel tank.
15. A direct methanol fuel cell system comprising the fuel mixing tank of any one of claims 1 to 14.
1. A fuel tank for a direct methanol fuel cell system in which a fuel tank, an air electrode, and a fuel electrode respectively receive undiluted methanol fuel, a cathode effluent, and an anode effluent,
A loss and a loss separated upwardly and downwardly by the separating plate,
And a gas outlet for discharging the gas to the outside is formed in the discharge space,
Wherein the fuel electrode outlet is provided with the fuel electrode discharge inlet, the raw liquid methanol inlet from which the raw methanol fuel is supplied from the fuel tank, and the fuel supply port that supplies the mixed fuel to the fuel electrode,
Wherein the separating plate is a tube penetrating the separating plate, the upper portion being disposed in the upper chamber, the lower portion being a water supply channel disposed in the lower portion, and a gas delivery portion for allowing the gas in the lower portion to be transferred to the lower chamber,
Wherein at least two flow-preventing plates having a moving hole are formed on the inner side of the container so that the mixed fuel can move up and down.
17. The method of claim 16,
And one of the flow preventing plates is formed to be higher than a normal water level of the mixed fuel in the fuel tank of the direct methanol fuel cell system.
17. A direct methanol fuel cell system, comprising the fuel mixing tank of claim 16 or 17.

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