KR20030042640A - System for Heating and Moisturing Air Entering into Cathode in Fuel Cell Stack - Google Patents

Abstract

PURPOSE: An air heating and humidifying system in a cathode of a fuel cell stack is provided, to heat or humidify the air flown into a cathode for supplying oxygen used as an oxidizing agent in the cathode by using the gas exhausted from the cathode. CONSTITUTION: The air heating and humidifying system is such that it heats and humidifies air by passing the gas exhausted from a cathode through a humidity membrane exchanger(1) and passing the air flown into the cathode through the humidity membrane exchanger(1), thereby allowing the heat of air to be exchanged by the exhausted gas. Preferably a splitter(2) is installed to separate liquid water contained in the exhausted gas before the gas exhausted from the cathode is flown into the humidity exchanger. Preferably the inner space of the humidity exchanger contains a plurality of membrane units which are layered perpendicularly each other.

Description

System for Heating and Moisturing Air Entering into Cathode in Fuel Cell Stack}

Field of invention

The present invention relates to a fuel cell stack. More specifically, the present invention relates to a system for humidifying or heating air entering the cathode to supply oxygen used as an oxidant at the cathode by using a gas emitted from the cathode of the fuel cell stack.

Background of the Invention

The fuel cell is supplied with hydrogen as the fuel gas to the anode and oxygen as the oxidant to the cathode to supply water to the hydrogen and oxygen to promote ionization to separate electrons from the hydrogen and oxygen. Humidifiers are used.

As a humidifier for fuel cells that has been used up to now, a thin film for supplying water to a fluidized bed of a gas by using a bubbler method and a polymer membrane to supply moisture by passing a late body filled with water into a pressure vessel through a diffuser. There is a humidification method and a direct injection method of supplying water directly to a gas inlet pipe through a slenoid valve by calculating a water content required for a fuel cell reaction. However, the bubbler method up to now has a large energy consumption due to its large size, and the thin film humidification method has difficulty in controlling the water supply amount, and the direct injection method has difficulty in controlling the water supply amount and making the water particles fine. Doing.

Korean Patent Application No. 1999-63739 (filed Dec. 28, 1999) consists of a water storage unit, a sponge, a plate having a plurality of holes, and a porous membrane, which can be mounted on the cathode and anode lines of a fuel cell, respectively. A humidifier for batteries is disclosed. This humidifier is not a device for heating or humidifying the air entering the cathode by using the gas discharged from the cathode.

SUMMARY OF THE INVENTION An object of the present invention is to provide a system for heating and humidifying air in a cathode capable of recovering gas discharged from the cathode of a fuel cell stack and reusing energy and moisture of the discharge gas.

Another object of the present invention is to provide a system for heating and humidifying air at a cathode for improving the performance of a fuel cell system by recovering gas discharged from the cathode to heat and humidify the air flowing into the cathode.

It is still another object of the present invention to provide a system capable of efficiently heating and humidifying air flowing into the cathode by recovering gas discharged from the cathode.

The above and other objects of the present invention can be achieved by the present invention described in detail below.

1 is a schematic view showing a heating system and heating system of air in a cathode according to the present invention.

2 is a schematic diagram showing the air flow of the humidification membrane exchanger according to the present invention.

3 is a perspective view schematically showing the interior of the humidification membrane exchanger according to the present invention.

4 is a perspective view showing a membrane unit installed inside the humidification membrane exchanger according to the present invention.

Brief description of the main symbols in the drawing

1: humidifier exchanger 2: splitter

3: fuel cell stack 11: exhaust gas inlet

12: outlet furniture outlet 13: air inlet

14: air outlet 15: interior space

16: inner partition 17, 18, 19, 20: hole

30: membrane unit 31: membrane

32: support

Summary of the Invention

The air heating and humidifying system at the cathode of the fuel cell stack according to the present invention passes the gas discharged from the cathode to the humidification membrane exchanger 1, and also the air flowing into the cathode is passed to the humidification membrane exchanger, thereby providing the air. Relates to a system in which heat is exchanged by the discharge gas to be heated and humidified. The humidification membrane exchanger is formed by stacking a plurality of membrane units 30 formed of a membrane 31 and a plurality of supports 32 while crossing each other by 90 degrees. Has a structure.

A splitter 2 may be further installed to separate the liquid water contained in the gas before the gas discharged from the cathode flows into the humidification membrane exchanger.

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

Detailed Description of the Invention

The heating and humidifying system of air in the cathode of the present invention is a system for heating and humidifying air entering the cathode by using the gas emitted from the cathode of the fuel cell stack. The gas emitted from the cathode of the fuel cell stack is a high temperature gas heated by the chemical reaction of the cell and contains oxygen, air, steam, high temperature water, and the like. These high-temperature emitters have not been recycled so far and have been discharged to the outside. In addition, oxygen to serve as an oxidant must be supplied to the cathode of the fuel cell stack, mainly air. At this time, the air must be heated in the fuel cell stack to promote the chemical reaction of the cell. Therefore, when the air heated beforehand is introduced into the cathode, the efficiency of the fuel becomes high.

1 is a schematic diagram of a system for heating and humidifying air entering a cathode by using a gas exiting the cathode according to the present invention. Although FIG. 1 shows a splitter 2 for separating a part of steam contained in a gas from a cathode and liquid water, this splitter is not a necessary equipment. That is, in the system without a splitter, gas from the fuel cell stack 3 flows directly into the humidification membrane exchanger 1. Even if the gas contains a small amount of liquid water, there is no problem because it does not affect the operation of the humidifier.

In the humidification membrane exchanger 1, the gas from the cathode and the air flowing into the cathode cross each other by approximately 90 degrees, and moisture and heat are introduced into the air from the hot gas containing the moisture, so that the air is humidified and heated. 2 is a view showing the air flow of the humidification membrane exchanger according to the present invention, Figure 3 is a perspective view showing the inside thereof. The gas from the cathode flows into the internal space 15 of the humidification membrane exchanger 1 through the exhaust gas inlet 11 and is discharged back to the exhaust gas outlet 12. Air is introduced into the internal space of the humidification membrane exchanger through the air inlet 13 and is discharged to the air outlet 14 and flows into the fuel cell stack 1.

As shown in FIG. 3, an inner partition 16 of a tetrahedron is formed in the humidifier membrane exchanger so that an inner space 15 is formed, and holes are formed in each inner partition so that gas and air can pass therethrough. 17, 18, 19, 20) are formed.

In the inner space 15 of the humidification membrane exchanger, the membrane unit 30 shown in FIG. The membrane unit 30 is coupled to a plurality of supports 32 having a predetermined height and width on the membrane 31, a plurality of channels are formed so that air or gas can flow.

The membrane 31 is a processable membrane that is easy to transfer heat and easy to pass steam, and is usually an ultrafiltration membrane, a reverse osmosis membrane, a hydrocarbon membrane, a perfluorosulfonic acid membrane, or a perfluorosulfonic acid membrane. membrane) and the like can be preferably used. In addition, the support 32 is made of a synthetic resin as a raw material, a resin such as PP, PE, PET, nylon may be preferably used.

The plurality of membrane units 30 are stacked while intersecting 90 degrees with the inner space 15 of the humidification membrane exchanger. Typically 10 to 50 membrane units can be stacked, but is not necessarily limited thereto.

Since the membrane units 30 are stacked while crossing each other at 90 degrees, air and gas flow along channels formed in different directions. However, because they are in contact with adjacent channels by the membrane 31, even if air and gas flow in different directions along different channels, heat is transferred through the membrane and moisture is transferred. Therefore, the hot gas containing the moisture released from the cathode raises the temperature of the air and also supplies the moisture to the air. Air heated and humidified in this way enters the fuel cell stack 1 and is used efficiently.

As shown in FIG. 1, a splitter 2 may be provided to allow gas from the fuel cell stack 3 to pass through before entering the humidification membrane exchanger 1. At this time, the splitter serves to remove the liquid high temperature water from the gas. When hot water is removed, the gas consists of hot oxygen, steam, air, and the like, which is introduced into the humidification membrane exchanger to heat and humidify the air. The water separated in the splitter may be discharged outside or recover waste heat in a heat exchanger (not shown).

The present invention recovers the gas discharged from the cathode of the fuel cell stack, recycles the energy and moisture of the discharge gas, efficiently heats and humidifies the air flowing into the cathode, and improves the performance of the fuel cell system. Has the effect of providing a heating and humidifying system of air.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (7)

The gas discharged from the cathode is passed through the humidification membrane exchanger 1, and the air flowing into the cathode is also passed through the humidification membrane exchanger, and the air is heat-exchanged by the discharge gas to heat and humidify the fuel cell. Air heating and humidifying system at the cathode of the stack. According to claim 1, wherein the inner membrane of the tetrahedron 16 is formed so that the inner space 15 is formed inside the humidification membrane exchanger 1, each of the inner partitions to allow the gas and air to pass through (17, 18, 19, 20), wherein the air heating and humidifying system at the cathode of the fuel cell stack. The heating and humidifying system of air at the cathode of the fuel cell stack according to claim 1, wherein a plurality of membrane units (30) are stacked in the internal space of the humidification membrane exchanger while crossing each other by 90 degrees. The method of claim 3, wherein the membrane unit 30 is composed of a membrane 31 and a plurality of supports 32, a plurality of supports having a predetermined height and width on the membrane coupled to the air or gas can flow A system for heating and humidifying air at a cathode of a fuel cell stack, characterized in that a plurality of channels are formed. The method of claim 4, wherein the membrane 31 is from the group consisting of ultra filtration membrane (Ultra filtration membrane, Reverse Osmosis membrane, Hydrocarbon membrane and Perfluorosulfonic Acid membrane) Air heating and humidifying system at the cathode of the fuel cell stack, characterized in that selected. 5. The system of claim 4, wherein the support (32) is selected from the group consisting of PP, PE, PET, and nylon resins. The fuel cell stack of claim 1, further comprising a splitter (2) installed to separate the liquid water contained in the discharge gas before the gas discharged from the cathode flows into the humidification membrane exchanger. And heating system of air at the cathode of the furnace.