CN1567629A

CN1567629A - Fuel cell cleaning device taking boron compounds as fuel

Info

Publication number: CN1567629A
Application number: CNA031300782A
Authority: CN
Inventors: 金铁焕; 李明浩; 曺泰熙; 朴明硕; 黄龙俊; 高承兑; 许成根; 崔鸿
Original assignee: LG Electronics Tianjin Appliances Co Ltd
Current assignee: LG Electronics Tianjin Appliances Co Ltd
Priority date: 2003-06-17
Filing date: 2003-06-17
Publication date: 2005-01-19

Abstract

The invention provides a fuel cell, using a fuel supply pipe to supply B compound stored in a fuel tank to the anode of a cell pile, using an air supply pipe to supply the air to the cathode of the cell pile, using the chemical reaction of the B compound with the air to obtain electromotive force (emf), and its characteristic: it is provided with a fuel cell cleaner using the B compound as a fuel and including connection pipe and three-way valve. The connection pipe connects the fuel and air supply pipes and the three-way valve is arranged at the vertical intersection of the connection and fuel supply pipe, and thus, as it is necessary, by changing the flow of the fluid, it uses the air to clean the insides of the fuel supply pipe and the cell pile.

Description

Fuel cell cleaning device using boron compound as fuel

Technical Field

The present invention relates to a FUEL CELL that generates electricity by electrochemical reaction using FUEL and air supplied from the outside, and more particularly, to a FUEL CELL cleaning device (PURGE APPARATUS FOR FUEL CELL) using a boron (B) compound as a FUEL, which can prevent clogging of a transfer line or corrosion of the line due to chemical action when unnecessary FUEL is accumulated in a CELL stack or a transfer line.

Background

In general, a fuel cell is a device for directly converting energy of fuel into electric energy, and such a fuel cell system generally includes a polymer electrolyte membrane as a center, an ANODE (ANODE) and a CATHODE (CATHODE) closely attached to both sides of the polymer electrolyte membrane, an electrochemical oxidation reaction of hydrogen as fuel is performed on the ANODE (an oxidation electrode or a fuel electrode), an electrochemical reduction reaction of oxygen as an oxidant is performed on the CATHODE (a reduction electrode or an air electrode), and electric energy is generated by movement of electrons generated at this time.

In a Proton semi-permeable Membrane fuel cell (PEMFC system), hydrogen gas supplied to the fuel cell is Liquefied Natural Gas (LNG), Liquefied Petroleum Gas (LPG), or methanol CH₃Hydrogen (H) extracted from hydrocarbon (CH series) fuel such as OH, gasoline, etc. in the course of desulfonation engineering → conversion reaction → hydrogen refining in the conversion furnace₂) In gaseous form; alternatively, in Boron Fuel cells (BFC, Boron Fuel Cell), solid-state tetrahydroboron anions (BH)₄ ^-) And converting into an aqueous solution state, and directly using the aqueous solution as fuel.

The Boron Fuel Cell (BFC) type fuel cell described above does not use a reformer, but supplies the aqueous solution state BH directly to the anode of the power generation device STACK (STACK)₄ ^-Thereby realizing the conversion reaction generated on the electrode, and therefore, the method has the advantages that a converter is not needed, and the whole system can be simplified.

However, the fuel cell using a boron (B) compound as a fuel in the related art as described above has the following problems:

BH in an aqueous solution state remains on the line during long periods of inactivity of the fuel cell₄ ^-Thus precipitating the B compound and precipitating boron dioxide (BO) when the aqueous solution is dried₂ ^-) The gel state causes clogging of the piping and corrosion of the fuel supply pipe.

And also BH₄ ^-When the catalyst is retained in the cell stack for a long time, the catalyst may be degraded by an unwanted reaction.

Disclosure of Invention

The object of the present invention is to provide a fuel cell using a boron compound as a fuel, which does not have the above-mentioned problems.

It is another object of the present invention to provide a cleaning device for a fuel cell which prevents occurrence of clogging of piping or degradation of catalyst performance. That is, when the system is not operated for a long time, the inside of the piping and the stack is cleaned with air,so that the clogging of the piping or the deterioration of the catalyst due to the occurrence of the deposition of compounds and unwanted reactions can be prevented.

In order to achieve the above object, the present invention provides a fuel cell which supplies a boron (B) compound stored in a fuel tank to an anode of a cell stack through a fuel supply pipe, supplies air to a cathode of the cell stack through an air supply pipe, and obtains an electromotive force from a chemical reaction between the supplied boron (B) compound and the air, characterized in that a fuel cell cleaning apparatus using the boron (B) compound as a fuel is provided, which includes a connection pipe and a three-way valve. The connecting pipe connects the fuel supply pipe and the air supply pipe, the three-way valve is arranged at the vertical intersection position of the connecting pipe and the fuel supply pipe, and the fuel supply pipe and the inner part of the cell stack are cleaned by air by changing the flow of fluid when needed.

The cleaning device for a fuel cell using a boron (B) compound as a fuel according to the present invention has the following effects:

the cleaning device of the fuel cell is provided with a connecting pipe which connects the fuel supply pipe and the air supply pipe, and a three-way valve is arranged at the vertical intersection position of the connecting pipe and the fuel supply pipe, so that when the fuel cell does not operate for a long time, due to the action of the three-way valve, under the state of cutting off the fuel supplied to the cell stack, a part of the air supplied to the air supply pipe is supplied to the fuel gas flow channel groove of the cell stack through the fuel supply pipe, and the inside of the cell stack is cleaned, thereby preventing the problems of flow channel blockage caused by the deposition of compounds caused by the long-time retention of the fuel in the fuel supply pipe andthe cell stack or reducing the service life of the catalyst.

Drawings

FIG. 1 is a schematic diagram showing the structure of a fuel cell of the present invention having a cleaning device and using a boron (B) compound as a fuel.

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

Fig. 3 is a piping diagram showing the start-up of the fuel cell of the invention.

Fig. 4 is a piping diagram showing the fuel cell of the present invention when it is not started for a long time.

Description of the reference numerals of the main components

10: the cell stack 22: anode

23: cathode 30: fuel supply pipe

50: air supply pipe 100: fuel tank

200: connecting pipe 201: three-way valve

Detailed Description

Hereinafter, an embodiment of a fuel tank of a fuel cell using a boron (B) compound as a fuel according to the present invention will be described in detail with reference to the accompanying drawings, in which:

As shown in the figure, the overall configuration of the fuel cell 1 is: one side of the cell stack 10 for generating electricity is provided with a state BH for storing an aqueous solution₄ ^-The fuel tank 100 of (1) is connected to the fuel tank 100 and the anode of the cell stack 10 via a fuel supply pipe 30 and a fuel recovery pipe 40, and the fuel supply pipe 30 is provided with a fuel pump 300 for sucking fuel. In addition, an air supply pipe 50 and an air discharge pipe 60 are provided at the cathode of the stack 10, and an air pump 70 for sucking the supplied air is provided at the air supply pipe 50.

The cell stack 10 may be a single cell (SINGLE CELL) in which electrochemical reactions occur or a combination of multiple single cells stacked in series and screwed together. The structure of a single battery is explained with reference to fig. 2, the single battery including: a Membrane-Electrode Assembly (MEA) 24, a Separator 25, and

collector plates

26, 27. An anode 22 and a cathode 23 for diffusing gas are attached to both sides of the electrolyte MEMBRANE 21, thereby forming a MEMBRANE-ELECTRODE ASSEMBLY (MEA) 24; SEPARATORs (SEPARATOR)25 closely attached to both sides of the membrane-electrode assembly 24 and forming flow paths for the fuel gas and air in the anode 22 and the cathode 23;

current collector plates

26 and 27 provided on both sides of the separator 25 and forming collector electrodes of the anode 22 and the cathode 23.

The electrolyte membrane 21 of the membrane-electrode assembly 24 is an ion exchange membrane made of a polymer material, a typical commercial electrolyte membrane 21 is a Nafion membrane of dupont, which has a function of a hydrogen ion conductor and a function of blocking contact between oxygen and hydrogen, and the anode 22 and the cathode 23 are carriers supporting a platinum Pt catalyst layer and are formed by attaching porous CARBON PAPER (CARBON PAPER) or CARBON cloth (CARBON cloth) to both sides of the electrolyte membrane 21.

The separator 25 is a carbon plate made of a dense material and has a plurality of ribs formed thereon, so that a fuel gas channel groove 31 is formed on the surface of the anode 22 and an oxygen gas channel groove 32 is formed on the surface of the cathode 23 during assembly.

The material of the

current collector plates

26 and 27 is required to have high conductivity and high corrosion resistance without weakening hydrogen gas, and specifically, any material satisfying the above requirements, such as titanium, stainless steel, or copper, is used.

Further, a connection pipe 200 for connecting the fuel supply pipe 30 and the air supply pipe 50 is provided, and a three-way valve 201 for air-cleaning a part of the fuel supply pipe 30 and the flow path in the stack is provided at a position where the connection pipe 200 and the fuel supply pipe 30 perpendicularly intersect, as necessary.

The fuel cell with the purging device according to the present invention will be described below with respect to the case where fuel is supplied and the case where fuel is not supplied.

Fig. 3 is a piping diagram showing the operation of the fuel cell of the invention.

As shown in the drawing, when the operator operates the switch of the fuel cell 1, the fuel pump 300 is operated according to a control program preset in a control unit (not shown), and thus the state BH of the aqueous solution stored in the fuel tank 100 is supplied through the fuel supply pipe 30₄ ^-While the fuel of (b) is supplied to the anode of the stack 10, the air pump 70 is driven to supply air to the cathode of the stack 10 through the air supply pipe 50.

BH in the state of the aqueous solution supplied to the cell stack 10 as described above₄ ^-Flows along the fuel gas flow path groove 31, and electrochemically oxidizes the fuel while diffusing over the entire surface of the anode 22 of the membrane-electrode assembly 24, and air flows along the oxygen flow path groove 32, electrochemically reduces the oxygen while diffusing over the entire surface of the cathode 23 of the membrane-electrode assembly 24, and the electrons generated at this time move to generate electricity, which is collected by the

current collecting plates

26 and 27 and used as an energy source.

The reaction equation at this time is as follows:

E₀＝1.64V

fig. 4 is a piping diagram showing the fuel cell of the present invention when it is not operated for a long time.As shown in the figure, when the fuel cell is not operated for a long time, the fuel supplied to the stack 10 by the action of the three-way valve 201 is cut off, and a part of the air supplied through the air supply pipe 50 is supplied to the fuel supply pipe 30 and the stack 10 through the connection pipe 200 as indicated by an arrow, the air supplied to the stack 10 makes BH present on the inside of the fuel gas flow path groove 31₄ ^-，BO₂ ^-And 2H₂The O-mixed liquid is discharged to the outside of the stack 10, and the air cleans the inside of the fuel gas flow channel 31, thereby preventing deposition of unnecessary compounds occurring in the pipe or the stack 10 and deterioration of the catalyst performance caused by the above reaction.

Claims

1. A fuel cell using a boron compound as a fuel, which supplies a boron compound stored in a fuel tank (100) to an anode of a cell stack (10) through a fuel supply pipe (30), supplies air to a cathode of the cell stack (10) through an air supply pipe (50), and obtains an electromotive force by a chemical reaction between the supplied boron compound and the air, characterized by further comprising:

a fuel cell cleaning device including a connection pipe and a three-way valve; the connecting pipe connects the fuel supply pipe and the air supply pipe; the three-way valve is disposed at a position where the connection pipe and the fuel supply pipe vertically intersect, and further, the fuel supply pipe and the inside of the stack are cleaned with air by changing the flow of fluid as needed.

2. The fuel cell fueled with a boron compound according to claim 1, wherein: the boron compound is a tetrahydroboron anion.