KR20040000566A - Humidification device for fuel cell - Google Patents

Abstract

PURPOSE: A humidifying device for a fuel cell using a B compound as fuel is provided, to simplify the structure of a humidifier and to allow the humidifier to be operated without the supply of electric power. CONSTITUTION: The fuel cell supplies the B compound stored at a fuel tank to the anode of stack, supplies the air in steam state from a humidifier(100) to the cathode of stack, and obtains the electromotive force from the chemical reaction of the B compound and the air, wherein the humidifier(100) comprises a water tank(101); a humidifying chamber(102) which is communicated with the top part of the water tank and has an air entrance hole(102a) at one side and an air exit hole(102b) at the other side; and a water absorbent(103) which is placed inside the humidifying chamber to allow its under part to be submerged under the water of the water tank for humidifying the air passing through. Preferably the B compound is BH4- in aqueous solution state. The water absorbent is a porous material, and preferably sponge.

Description

Humidifier for fuel cells, fueled by compounds

The present invention relates to a fuel cell that generates electricity through an electrochemical reaction between fuel and air supplied from the outside, and more particularly, a humidifier of a fuel cell using a B compound having a simple structure as a fuel without power consumption. It is about.

In general, a technique related to a fuel cell is known as a device for directly converting energy contained in a fuel into electrical energy, and such a fuel cell generally has a porous anode (ANODE) and a cathode (CATHODE) on both sides of a polymer electrolyte. Is attached, the electrochemical oxidation of hydrogen as a fuel occurs at the anode (anode or anode), and the electrochemical reduction of oxygen as an oxidant at the cathode (reduction electrode or cathode). 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. It is used in the form of BFC or solid state BH ₄ ^- which is supplied as an aqueous solution and used directly as a fuel.

The BFC fuel cell does not require a reformer, and thus reformulates the electrode in a manner of directly supplying BH ₄ ^- in aqueous solution to the anode of the stack, which is a power generation device, so that the reformer is unnecessary, thereby simplifying the entire system. It has a big advantage.

However, the BFC fuel cell using the conventional BH ₄ ^- as the fuel is supplied in a vapor state generated by a humidifier using ultrasonic heating when air is supplied to the cathode of the stack. The humidifier installed as such Power should always be used, the configuration is complicated, and long-term use had a problem that the cleaning is not good.

The object of the present invention devised in view of the above problems is to provide a humidification device of a fuel cell, which is composed of a simple structure and has no power consumption of B compound as a fuel.

1 is a schematic configuration diagram showing a fuel cell fueled with compound B having a humidification device of the present invention.

Figure 2 is a cross-sectional view showing a single cell structure of the stack according to the present invention.

Figure 3 is a longitudinal sectional view showing a humidifier according to the present invention.

Explanation of symbols on the main parts of the drawings

10: stack 20: fuel tank

22: anode 23: cathode

100: humidifier 101: water tank

102: humidification chamber 102a: air inlet

102b: air outlet 103: water absorbing material

W: water

In order to achieve the object of the present invention as described above, the B compound stored in the fuel tank is supplied to the anode of the stack, and the air of the vapor state in the humidifier is supplied to the cathode of the stack, and from the chemical reaction of the supplied B compound and air In a fuel cell obtaining an electromotive force,

The humidifier is formed to communicate with the water tank containing the water, the upper side of the water tank, the air inlet is formed on one side and the air outlet is formed on the other side, and the lower end is submerged in the water of the water tank There is provided a humidification apparatus of a fuel cell using B-compound as a fuel, characterized in that it is composed of a water absorbent for humidifying the air passing through the inside of the humidification chamber.

Hereinafter, with reference to the embodiment of the accompanying drawings, a fuel cell using the B compound as a fuel having the humidifying apparatus of the present invention configured as described above will be described in more detail.

1 is a schematic configuration diagram showing a fuel cell fueled with compound B equipped with a hydrogen gas removing apparatus of the present invention.

As shown, the overall configuration of the fuel cell 1 is provided with a fuel tank 20 for storing BH ₄ ⁻ in an aqueous solution state on one side of the stack 10 generating electricity. The anode of the tank 20 and the stack 10 is connected to the fuel supply line 30 and the fuel recovery line 40, the fuel supply line 30 is provided with a fuel pump 50 for pumping the fuel It is.

In addition, the cathode of the stack 10 is connected to the air supply line 60 and the air discharge line 70, the air supply line 60 is installed with an air pump 80 for pumping the supplied air A humidifier 100 is provided between the air pump 80 and the stack 10 to humidify the air supplied to the air supply line 60 by the air pump 80.

The stack 10 may be a single cell in which an electrochemical reaction occurs or a plurality of single cells may be sequentially stacked and assembled into bolts. Referring to FIG. 2, a single cell structure will be described. 11, a membrane-electrode assembly (MEA: MEMBRANE-ELECTRODE ASSEMBLY) 14 formed by bonding the anode 12 and the cathode 13 for diffusing a gas to both sides, and both sides of the membrane-electrode assembly 14. It is assembled so as to be in close contact with the bipolar plate (BIPOLAR PLATE) 15 to form a flow path of fuel gas and oxygen-containing gas in the anode 12 and the cathode 13, and disposed on both sides of the bipolar plate 15 12 and current collector plates 16 and 17 serving as collector electrodes of the cathode 13.

The electrolyte membrane 11 of the membrane-electrode assembly 14 is an ion exchange membrane made of a polymer material, and the commercially available electrolyte membrane 11 includes a Nafion membrane of DuPont, which serves as a carrier for hydrogen ions, The anode 12 and the cathode 13 serve to support the platinum (Pt) catalyst layer, and porous carbon paper (CARBON PAPER) or carbon cloth (CARBON CLOTH) is formed on both sides of the electrolyte membrane 11. It is a bonded structure.

The bipolar plate 15 is a dense carbon plate, and a plurality of flow path grooves 15a formed at a predetermined depth are formed on an inner side thereof, and the bipolar plate 15 is in close contact with the positive electrode 12 and the negative electrode 13. BH ₄ ^-, BO is _2, the mixture of air and 2H ₂ O are to flow respectively.

It is preferable that the current collector plates 16 and 17 have excellent electrical conductivity, excellent corrosion resistance, and do not generate hydrogen embrittlement. Specifically, any of the collector plates 16 and 17 may satisfy the required performance such as titanium, stainless steel, and copper. Also good.

The humidifier 100 is formed so as to communicate with the water tank 101 in which the water (W) is contained, the upper side of the water tank 101, the air inlet (102a) is formed on one side and the air outlet (102b) on the other side Is provided in the humidification chamber 102 and the water absorbing material 103 for humidifying the air passing through the inside of the humidification chamber 102 so that the lower end is immersed in the water (W) of the water tank 101. Consists of.

The water absorbing material 103 is a porous material that can be absorbed by the capillary principle, is a kind of sponge-like material.

The effect of the fuel cell having the humidification device of the present invention configured as described above will be described.

When the operator operates the switch of the fuel cell 1, the fuel pump 50 is operated in accordance with a control program preset by an electronic controller (not shown) to fuel BH ₄ ^- in an aqueous state stored in the fuel tank 20. By supplying the anode 12 of the stack 10 through the supply line 30 and operating the air pump 80, the air humidified in the humidifier 100 through the air supply line 60 is transferred to the stack 10. Supply to the cathode (13).

As described above, BH ₄ ⁻ in an aqueous solution state supplied to the stack 10 flows along the flow path formed by the flow path grooves 15a and diffuses to the entire surface of the anode 12 of the membrane-electrode assembly 14 to electrochemically hydrogen Oxidation proceeds, and air flows along the oxygen-containing gas flow path groove 15a and diffuses to the front surface of the cathode 13 of the membrane-electrode assembly 14 to cause electrochemical reduction of oxygen. The electricity is generated, and the generated electricity is collected at the current collector plates 16 and 17 and used as an energy source.

The reaction scheme at this time is as follows.

_{^{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 2}} → 2H 2 O + BO 2 E 0 = 1.64 V

In the humidifier 100, the dry air introduced into the humidification chamber 102 through the air inlet 102a passes through the water absorbent 103 where water is absorbed, and is changed to humidified air. Since the air is discharged through the air outlet 102b and supplied to the cathode 13 of the stack 10, it does not need electric power to operate like a conventional humidifier, its structure is simple, and manufacturing cost is reduced, Very easy.

As described above in detail, the humidification apparatus of a fuel cell fueled by the compound B of the present invention includes a humidification chamber above the water tank, and a water absorbent material in the humidification chamber so that the lower end is immersed in the water of the water tank. Since the air introduced into the humidification chamber passes through the water absorbent and is humidified and then supplied to the cathode of the stack, the structure of the humidifier is simply configured, thereby reducing the manufacturing cost and providing very good cleaning. It works.

In addition, since the power supply to the humidifier is not made, there is an effect of preventing unnecessary power consumption.

Claims (4)

In a fuel cell that supplies the B compound stored in the fuel tank to the positive electrode of the stack, the humidifier supplies air in the vapor state to the negative electrode of the stack, and obtains an electromotive force from the chemical reaction of the supplied B compound and air. The humidifier is formed to communicate with the water tank containing the water, the upper side of the water tank, the air inlet is formed on one side and the air outlet is formed on the other side, and the lower end is submerged in the water of the water tank A humidifier of a fuel cell comprising B compound as a fuel, characterized in that it is composed of a water absorbing material for humidifying air passing through the inside of the humidification chamber. 2. The hydrogen gas removal apparatus of a fuel cell according to claim 1, wherein the compound B is BH ₄ ^- in an aqueous solution. The hydrogen gas removal apparatus of a fuel cell of claim 1, wherein the water absorbing member is a porous material for absorbing water. 4. The humidifier of a fuel cell of claim 3, wherein the porous material is a sponge.