KR100533008B1 - Fuel cell system having water trap apparatus - Google Patents

Abstract

A fuel cell system having a water collecting device of the present invention comprises a generator in which power generation is performed by electrochemical oxidation at an anode and electrochemical reduction at a cathode, a fuel tank in which fuel is stored, and an anode of the fuel tank and the generator. A fuel supply line to communicate with, an air supply line communicating with the cathode inlet of the generator, a fuel discharge line communicating with the anode outlet of the generator and discharging the fuel after the reaction, and a cathode outlet of the generator Air discharge lines for discharging air after the reaction, gas-liquid separators connected to the fuel discharge line and the air discharge line to separate the fuel and air after the reaction into liquid and gas, and installed in the air supply line In the fuel cell system comprising a humidifier for humidifying, the humidifier is installed after the humidifier of the air supply line Standing the humidified air that is being configured to include a water trap for trapping H ₂ O of the liquid contained in the air supplied to the cathode of the generator through the air supply line, and supplied to the cathode of the generator through the air supply line H ₂ O in the liquid state contained in the water trap is trapped in the water trap so that only air and water vapor H ₂ O are supplied to the cathode of the generator, so that the air supplied to the cathode and H ₂ O in the water vapor state are active with the catalyst. As it progresses, the power generation performance of the system is improved.

Description

FUEL CELL SYSTEM HAVING WATER TRAP APPARATUS}

The present invention relates to a fuel cell system that generates electricity through an electrochemical reaction between fuel and air supplied from the outside, and particularly, collects H ₂ O in a liquid state contained in air supplied to the cathode to the cathode. The present invention relates to a fuel cell system having a water collecting device in which only H ₂ O in an air and steam state is supplied to enable an active reaction to a catalyst by H ₂ O in an air and steam state.

In general, a fuel cell system is a device that directly converts the energy contained in the fuel into electrical energy, and the generator of such a fuel cell system usually has an anode and a cathode on both sides of a polymer electrolyte membrane. ), Electrochemical oxidation of hydrogen as a fuel at the anode (anode or anode), and electrochemical reduction of oxygen as oxidant at the cathode (reduction electrode or cathode). Energy is generated.

Hydrogen supplied to such a fuel cell is purified by purifying only hydrogen (H ₂ ) from a hydrocarbon-based (CH-based) fuel such as LNG, LPG, CH ₃ OH, and gasoline through a desulfurization process → reforming reaction → hydrogen purification process. PEMFC (Proton Exchange Membrane Fuel Cell) used in the form, and BFC (Boron Fuel Cell) which directly uses BH ₄ ^- in the form of an aqueous solution and uses it as a fuel are introduced.

A schematic configuration of a conventional BFC is illustrated in FIG. 1, which will be briefly described as follows.

As shown, the conventional fuel cell 1 is provided with a fuel tank 2 for storing BH ₄ ⁻ in an aqueous state on one side of the generator 10 generating electricity, the fuel tank (2) And the anode of the generator 10 is connected to the fuel supply line 3 and the fuel discharge line 4, the fuel supply line 3 is provided with a fuel pump 5 for pumping fuel.

In addition, an air supply line 6 and an air discharge line 7 are installed at the cathode of the generator 10. The air supply line 6 has an air filter 8 for pumping the supplied air and air. The compressor 9 and the humidifier 11 are provided.

Further, gas-liquid separators 12 and 12 'are respectively installed in the fuel discharge line 4 and the air discharge line 7, and the fuel and water separated from the gas-liquid separators 12 and 12' are fuel. A collection line 13 is connected to the tank 2 so that the fuel or water after the reaction separated in the gas-liquid separator 12 and 12 'is connected to the fuel tank 2. A circulation pump 14 for pumping is installed.

In the drawings, reference numerals 15 and 15 'denote valves.

In the conventional fuel cell system configured as described above, when the operation switch of the device is turned on, the fuel pump 5 pumps BH ₄ ⁻ in an aqueous state stored in the fuel tank 2 through the fuel supply line 3. The air compressor 8 is operated at the same time as supplying to the positive electrode (fuel electrode) of the generator 10 so that air is supplied to the negative electrode (air electrode) of the generator 10 through the air supply line 6.

As described above, the BH ₄ ⁻ and the air in the aqueous solution state supplied to the generator 10 are supplied to the anode and the cathode installed so that the catalyst is wrapped with carbon cloth on both sides with the polymer electrolyte membrane interposed therebetween. The electrochemical oxidation of, the electrochemical reduction of oxygen occurs at the cathode, the electricity is generated by the movement of the electrons generated at this time, the electricity generated at this time is collected in a current collector (not shown) to use as an energy source do.

The reaction formula at this time

The anode BH ₄ ^- + 8OH ^- → BO ₂ ^- (liquid) + 6H ₂ O (group) + 8e ^-

As a side reaction, 2H ₂ O + NaBH ₄ → NaBO ₂ (liquid) + 4H ₂ (group)

In the negative electrode 2O ₂ + 4H ₂ O (humidified ^{air) + 8e - → 8OH - +} H 2 O ( liquid), NaOH, to Air (group), a liquid and a gas generated from the positive electrode and the negative electrode after the reaction each of the gas-liquid separator The fuel and water after the reaction separated in (12) and (12 ') are circulated again by the circulation pump 14 and sent to the fuel tank 2 for reuse.

However, in the conventional fuel cell as described above, as well as H ₂ in the vapor state O in the cathode air and H ₂ O supplied to the generator 10 includes a H ₂ O in a liquid state, the liquid H ₂ O Since it surrounds the catalyst of the negative electrode to inhibit the reaction of H ₂ O in the air or steam state with the catalyst had a problem of lowering the power generation performance of the generator.

The object of the present invention devised in view of the above problems is to prevent the H ₂ O in the liquid state is supplied to the cathode of the generator so that the active catalyst proceeds by the H ₂ O in the air and water vapor state by the catalyst of the cathode The present invention provides a fuel cell system having a water collecting device to improve the power generation performance of a generator.

In order to achieve the object of the present invention as described above, the generator is generated by the electrochemical oxidation at the anode and the electrochemical reduction at the cathode, the fuel tank in which the fuel is stored, and the anode of the fuel tank and the generator A fuel supply line to communicate with, an air supply line communicating with the cathode inlet of the generator, a fuel discharge line communicating with the anode outlet of the generator and discharging the fuel after the reaction, and a cathode outlet of the generator Air discharge lines for discharging air after the reaction, gas-liquid separators connected to the fuel discharge line and the air discharge line to separate the fuel and air after the reaction into liquid and gas, and installed in the air supply line A fuel cell system comprising a humidifier to humidify,

It is installed after the humidifier of the air supply line is humidified in the humidifier and comprises a water trap for trapping the liquid H ₂ O contained in the air supplied to the cathode of the generator through the air supply line A fuel cell system having a water collecting device is provided.

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Hereinafter, with reference to the embodiment of the accompanying drawings a fuel cell system having a water collecting device of the present invention configured as described above in detail as follows.

Figure 2 is a schematic configuration diagram of a fuel cell system having a water collecting device of the present invention, as shown, the fuel cell system 100 of the present invention is generated by the electrochemical reaction of BH ₄ and air in an aqueous solution state A fuel tank 102 for storing BH ₄ in an aqueous state supplied to the anode 132 of the generator 101 at a predetermined distance from the generator 101 is provided. .

The lower portion of the fuel tank 102 and the inlet portion of the anode 132 of the generator 101 are connected to the fuel supply line 103 so as to supply fuel, and the outlet portion of the anode 132 is fueled. A discharge line 104 is connected, and the fuel supply line 103 is provided with a fuel pump 105 for pumping fuel.

In addition, an air supply line 109 is installed at the inlet of the cathode 133 of the generator 101 so that air can be supplied, and an outlet of the cathode 133 after reacting. The air discharge line 110 is installed so that air can be discharged.

The air supply line 109 includes an air filter 111 for filtering air supplied to the generator 101, an air compressor 112 for blowing air, and a humidifier for humidifying air ( Humidifier (113) is provided in sequence, and the rear of the humidifier 113 to collect the H ₂ O in the liquid state contained in the air supplied from the humidifier 113 to the cathode 133 of the generator 101. Water trap (150) is provided for.

In addition, the liquid H ₂ O collected in the water trap 150 is recovered to the humidifier 113 through a water recovery line 151 connected between the water trap 150 and the humidifier 113 to the water for humidification. It can be used.

In addition, the fuel and air discharged from the fuel discharge line 104 and the air discharge line 110 are connected to the respective gas-liquid separators 120 and 120 ', and the gas-liquid separators 120 and 120'. And the fuel tank 102 is connected to the water recycling line 122, the water recycling line 122, the circulation pump to pump the fuel and water separated from the gas-liquid separator 120 to the fuel tank 102 123 is provided.

The generator 101 may have a form in which a plurality of single cells are continuously stacked or a single cell. A single cell structure is described with reference to FIGS. 3 and 4, and an electrolyte membrane 131. A membrane-electrode assembly (MEA) formed by bonding the anode 132 and the cathode 133 for diffusing a gas to both sides of the electrode, and the membrane-electrode assembly 134 closely adheres to both sides of the membrane-electrode assembly 134. A separator 136 which is assembled so as to form a flow path 135 of fuel gas and oxygen-containing gas at the anode 132 and the cathode 133, and disposed on both sides of the separator 136. 132 and a collector plate 137 serving as a collector electrode of the cathode 133.

 The electrolyte membrane 131 of the membrane-electrode assembly 134 is an ion exchange membrane made of a polymer material, and the commercially available electrolyte membrane 131 includes a Nafion membrane of DuPont, which serves as a carrier of hydrogen ions, As shown in FIG. 4, the anode 132 and the cathode 133 serve as a support for supporting the platinum (Pt) catalyst layer 141, and the porous carbon cloth 142 is electrolyte. It has a structure bonded to both sides of the film 131.

The separating plate 136 is made of a dense carbon plate, and a plurality of flow path grooves are formed in the fluid to flow therein.

It is preferable that the current collector plate 137 is excellent in electrical conductivity, excellent in corrosion resistance, and does not generate hydrogen embrittlement. Specifically, any one of the current collector plate 137 may be satisfied as long as the required performance is satisfied.

In the fuel cell system having the water collecting device of the present invention configured as described above, when the operation switch of the device is turned on, power supplied from the battery is supplied to the fuel pump 105 through the power converter to supply the fuel pump 105. By operating the pump BH ₄ in the aqueous solution state stored in the fuel tank 102 is supplied to the anode 132 of the generator 101 through the fuel supply line 103.

In addition, the air compressor 112 supplies air to the cathode 133 of the generator 101 through the air supply line 109. The air supplied as such is humidified after being filtered by the air filter 111. At 113, humidified to the appropriate humidity is supplied.

As described above, the BH ₄ in the aqueous state supplied into the generator 101 flows along the flow path 135 formed on the outer surface of the positive electrode 132 with the electrolyte membrane 131 interposed therebetween, and the air is negative. Diffusion flows along the flow path 135 formed on the outer side of the 133, the electrochemical oxidation proceeds at the anode 132, the electrochemical reduction proceeds at the cathode 133, the electricity is generated by the movement of electrons In this case, the electricity generated at that time is collected in the current collector plate 137 and used as a power source.

The reaction formula of the reaction generated in the generator 101 is

_{^{Anode: BH 4 - + 8OH -}} → BO 2 - + 6H 2 O + 8e - E 0 = 1.24 V

_{Cathode: 2O 2 + 4H 2 O} + 8e - → BOH - E 0 = 0.4 V

Total: BH ₄ ^- + 2O a _{2 → 2H 2 O + BO 2} E 0 = 1.64 V.

As above, BH ₄ ^- in aqueous solution used as fuel is mixed with a certain amount of Na to make a stable solution.

Anode: 2H ₂ O + NaBH ₄ + 4H ₂ The reaction proceeds.

Then, the air and water discharged after the reaction in the anode and the fuel and gas and the cathode as described above is discharged to the gas-liquid separator (120, 120 ') through the fuel discharge line 104 and the air discharge line (110). The fuel and water after the reaction separated in the gas-liquid separators 120 and 120 'are pumped to the fuel tank 102 by the circulation pump 124 and reused, and the gas is discharged as it is.

In addition, when the power generation is made as described above, the air supplied through the air supply line 109 is humidified in the humidifier 113, the air and H ₂ O is supplied to the cathode 133 of the generator 101, At this time, the air supplied to the cathode 133 through the air supply line 109 and H ₂ O of the liquid state of H ₂ O is separated from the water trap 150 is collected in the inner bottom of the water trap 150, air And only H ₂ O in the steam state is supplied to the cathode 133 of the generator 101 is to actively react with the catalyst of the catalyst layer 141.

In addition, the liquid H ₂ O collected in the water trap 150 as described above is recovered to the humidifier 113 through the water recovery line 151 to be used as water for humidification.

As described in detail above, the fuel cell system having the water collecting device of the present invention is installed in the air supply line for supplying air to the cathode of the generator to install a water trap for collecting the liquid H ₂ O, the air in the humidifier Water supplied to the cathode of the generator through the supply line and H ₂ O in the liquid state contained in H ₂ O are collected in the water trap so that only air and steam H ₂ O are supplied to the cathode of the generator, thereby supplying it to the cathode. The active reaction of the H ₂ O in the air and water vapor state with the catalyst proceeds to improve the power generation performance of the system.

In addition, the liquid H ₂ O collected in the water trap as described above is recovered by the humidifier through the water recovery line to be used as water for the humidification, there is an effect that does not need to frequently supplement the water in the humidifier.

1 is a schematic configuration diagram showing a conventional fuel cell system.

2 is a schematic configuration diagram of a fuel cell system having a water collecting device of the present invention.

3 is a cross-sectional view showing a unit cell structure according to the present invention.

4 is an enlarged view illustrating a portion A of FIG. 3.

Explanation of symbols on the main parts of the drawings

101: generator 102: fuel tank

103: fuel supply line 104: fuel discharge line

109: air supply line 110: air discharge line

120,120 ': Gas-liquid separator 132: Anode

133: cathode 150: water trap

151: water recovery line

Claims (2)

A generator that generates power by electrochemical oxidation at the anode and electrochemical reduction at the cathode, a fuel tank in which the fuel is stored, a fuel supply line communicating the anode of the fuel tank with the generator, and a cathode inlet of the generator An air supply line communicating with the unit, a fuel discharge line communicating with the anode outlet of the generator and discharging the fuel after the reaction, an air discharge line communicating with the cathode outlet of the generator and discharging the air after the reaction; A fuel cell system comprising a gas-liquid separator connected to a fuel discharge line and an air discharge line, respectively, to separate the fuel and air after the reaction into a liquid and a gas, and a humidifier installed at the air supply line to humidify the air. It is installed after the humidifier of the air supply line is humidified in the humidifier and comprises a water trap for trapping the liquid H ₂ O contained in the air supplied to the cathode of the generator through the air supply line A fuel cell system having a water collecting device. The method of claim 1, And a water collection line connecting the water trap and the humidifier to supply the water trapped in the water trap to the humidifier to be used as water for humidification.