CN1815788A

CN1815788A - Fuel cell with high operation stability

Info

Publication number: CN1815788A
Application number: CNA2005100237323A
Authority: CN
Inventors: 夏建伟; 章波; 胡里清
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: State Grid Shanghai Electric Power Co Ltd; Shanghai Shenli Technology Co Ltd
Priority date: 2005-02-01
Filing date: 2005-02-01
Publication date: 2006-08-09
Anticipated expiration: 2025-02-01
Also published as: CN100454633C

Abstract

The disclosed fuel battery includes fuel cell pile, hydrogen storage, hydrogen reducing valve, unit for humidifying hydrogen, air compression supplying device, unit for humidifying air, coolant circulating pump, water-vapor separator for humidified air, water-vapor separator for humidified hydrogen etc. The water-vapor separator for humidified air, or water-vapor separator for humidified hydrogen includes body case. At least two layers of filtering layer are setup inside the body case. One end of the water-vapor separator for humidified air, or water-vapor separator for humidified hydrogen is connected to the outlet of unit for humidifying air or hydrogen, and the other end is connected to inlet of air or hydrogen in fuel cell pile. The invention makes humidified air or hydrogen of taking part in reaction of galvanic pile not containing liquid matter so as to raise stability of operation and prolong service life of fuel battery.

Description

Fuel cell with higher operation stability

Technical Field

The present invention relates to a fuel cell, and more particularly, to a fuel cell having high operation stability.

Background

An electrochemical fuel cell is a device capable of converting hydrogen and an oxidant into electrical energy and reaction products. The inner core component of the device is a Membrane Electrode (MEA), which is composed of a proton exchange Membrane and two porous conductive materials sandwiched between two surfaces of the Membrane, such as carbon paper. The membrane contains a uniform and finely dispersed catalyst, such as a platinum metal catalyst, for initiating an electrochemical reaction at the interface between the membrane and the carbon paper. The electrons generated in the electrochemical reaction process can be led out by conductive objects at two sides of the membrane electrode through an external circuit to form a current loop.

At the anode end of the membrane electrode, fuel can permeate through a porous diffusion material (carbon paper) and undergo electrochemical reaction on the surface of a catalyst to lose electrons to form positive ions, and the positive ions can pass through a proton exchange membrane through migration to reach the cathode end at the other end of the membrane electrode. At the cathode end of the membrane electrode, a gas containing an oxidant (e.g., oxygen), such as air, forms negative ions by permeating through a porous diffusion material (carbon paper) and electrochemically reacting on the surface of the catalyst to give electrons. The anions formed at the cathode endreact with the positive ions transferred from the anode end to form reaction products.

In a pem fuel cell using hydrogen as the fuel and oxygen-containing air as the oxidant (or pure oxygen as the oxidant), the catalytic electrochemical reaction of the fuel hydrogen in the anode region produces hydrogen cations (or protons). The proton exchange membrane assists the migration of positive hydrogen ions from the anode region to the cathode region. In addition, the proton exchange membrane separates the hydrogen-containing fuel gas stream from the oxygen-containing gas stream so that they do not mix with each other to cause explosive reactions.

In the cathode region, oxygen gains electrons on the catalyst surface, forming negative ions, which react with the hydrogen positive ions transported from the anode region to produce water as a reaction product. In a proton exchange membrane fuel cell using hydrogen, air (oxygen), the anode reaction and the cathode reaction can be expressed by the following equations:

and (3) anode reaction:

and (3) cathode reaction:

in a typical pem fuel cell, a Membrane Electrode (MEA) is generally placed between two conductive plates, and the surface of each guide plate in contact with the MEA is die-cast, stamped, or mechanically milled to form at least one or more channels. The flow guide polar plates can be polar plates made of metal materials or polar plates made of graphite materials. The fluid pore channels and the diversion trenches on the diversion polar plates respectively guide the fuel and the oxidant into the anode area and the cathode area on two sides of the membrane electrode. In the structure of a single proton exchange membrane fuel cell, only one membrane electrode is present, and a guide plate of anode fuel and a guide plate of cathode oxidant are respectively arranged on two sides of the membrane electrode. The guide plates are used as current collector plates and mechanical supports at two sides of the membrane electrode, and the guide grooves on the guide plates are also used as channels for fuel and oxidant to enter the surfaces of the anode and the cathode and as channels for taking away water generated in the operation process of the fuel cell.

In order to increase the total power of the whole proton exchange membrane fuel cell, two or more single cells can be connected in series to form a battery pack in a straight-stacked manner or connected in a flat-laid manner to form a battery pack. In the direct-stacking and serial-type battery pack, two surfaces of one polar plate can be provided with flow guide grooves, wherein one surface can be used as an anode flow guide surface of one membrane electrode, and the other surface can be used as a cathode flow guide surface of another adjacent membrane electrode, and the polar plate is called a bipolar plate. A series of cells are connected together in a manner to form a battery pack. The battery pack is generally fastened together into one body by a front end plate, a rear end plate and a tie rod.

A typical battery pack generally includes: (1) the fuel (such as hydrogen, methanol or hydrogen-rich gas obtained by reforming methanol, natural gas and gasoline) and the oxidant (mainly oxygen or air) are uniformly distributed in the diversion trenches of the anode surface and the cathode surface; (2) the inlet and outlet of cooling fluid (such as water) and the flow guide channel uniformly distribute the cooling fluid into the cooling channels in each battery pack, and the heat generated by the electrochemical exothermic reaction of hydrogen and oxygen in the fuel cell is absorbed and taken out of the battery pack for heat dissipation; (3) the outlets of the fuel gas and the oxidant gas and the corresponding flow guide channels can carry out liquid and vapor water generated in the fuel cell when the fuel gas and the oxidant gas are discharged. Typically, all fuel, oxidant, and cooling fluid inlets and outlets are provided in one or both end plates of the fuel cell stack.

The proton exchange membrane fuel cell can be used as a power system of vehicles, ships and other vehicles, and can also be used as a movable and fixed power generation device.

When the proton exchange membrane fuel cell can be used as a vehicle power system, a ship power system or a mobile and fixed power station, the proton exchange membrane fuel cell must comprise a cell stack, a fuel hydrogen supply system, an air supply subsystem, a cooling and heat dissipation subsystem, an automatic control part and an electric energy output part.

Fig. 1 is a fuel cell power generation system, in fig. 1, 1 is a fuel cell stack, 2 is a hydrogen storage bottle or other hydrogen storage device, 3 is a pressure reducing valve, 4 is an air filtering device, and 5 is an air compression supply device; 6. the hydrogen and air separator 6' is the hydrogen and air separator, the water tank 7, the cooling fluid circulating pump 8, the radiator 9, the hydrogen circulating pump 10, and the hydrogen and air humidifier 11, 12.

The operation of the fuel cell requires humidification of the air side and the hydrogen side to ensure the normal operation of the fuel cell. Because the humidifier is located a distance from the fuel cell air or hydrogen side inlet to the fuel cell air or hydrogen side inlet, water droplets tend to separate out of the gas stream, however, the collision between the water droplets creates larger water droplets, even as a water mass suspended in the gas stream, as shown in fig. 2. Once entering the galvanic pile, the large water drops or water mass suspended in the air flow can block the diversion trench on the diversion pole plate in the galvanic pile, and cause starvation of fuel or oxidant to the electrode, thereby causing great influence on the performance of the electrode, reducing the service life of the electrode, and causing the electrode to be scrapped in severe cases.

Disclosure of Invention

The present invention is directed to overcoming the above-mentioned drawbacks of the prior art, and providing a fuel cell with high operation stability, which can make the humidified air or hydrogen entering the stack to participate in the reaction contain no liquid substance, thereby improving the operation stability and prolonging the service life of the fuel cell.

The purpose of the invention can be realized by the following technical scheme: a fuel cell with high operation stability comprises a fuel cell stack, a hydrogen storage device, a hydrogen pressure reducing valve, a hydrogen humidifying device, an air filtering device, an air compression supply device, an air humidifying device, a pile hydrogen gas-steam separator, a hydrogen circulating pump, a pile air gas-steam separator, a water tank, a cooling fluid circulating pump and a radiator.

The filter layer is two layers.

The filter layer is made of porous glass or a porous plastic material membrane.

The humidified air or hydrogen water-steam separator is vertically arranged, the lower side part of the shell is provided with a humidified air or hydrogen inlet, the top of the shell is provided with a humid air or hydrogen outlet, the bottom of the shell is provided with a water outlet, and the water outlet is provided with a normally closed electromagnetic valve capable of controlling timed drainage.

The water outlet extends upwards to form an inverted horn shape.

The shell is cylindrical.

The invention adopts a special material, namely porous glass (or polytetrafluoroethylene porous membrane). When the gas stream flows through the humidified air or hydrogen water-vapor separator, the gas can diffuse away from the first porous glass surface while water molecules are rejected. To enhance the filtering effect, the gas after being filtered by one layer passes through the second layer of porous glass to fully filter the moisture in the gas flow. The filtered water is discharged through a drain pipe, so that the purpose of steam-water separation is achieved. The invention can obviously improve the stability of the fuel cell operation.

Drawings

FIG. 1 is a schematic diagram of a conventional fuel cell;

FIG. 2 is a schematic diagram of the formation of water droplets and suspended water clusters in the conduit between the outlet of the air or hydrogen humidifier and the air or hydrogen inlet of the stack in a prior art fuel cell;

fig. 3 is a schematic structural view of a fuel cell humidified air or hydrogen humidified water-vapor separator of the present invention.

Detailed Description

The invention will be further explained with reference to the drawings.

Example 1

As shown in FIG. 3, a 1-200 KW fuel cell with high operation stability comprises a fuel cell stack 1, a hydrogen storage device 2, a hydrogen pressure reducingvalve 3, an air filtering device 4, an air compression supply device 5, a stack-outlet hydrogen water-vapor separator 6, a stack-outlet air water-vapor separator 6', a water tank 7, a cooling fluid circulating pump 8, a radiator 9, a hydrogen circulating pump 10, a hydrogen humidifying device 11, an air humidifying device 12, and a humidified air or hydrogen water-vapor separator 13.

The humidified air or hydrogen water-vapor separator 13 includes a housing 131, and two filter layers 132 are disposed in the housing 131, wherein the filter layers 132 are made of porous glass.

The humidified air or humidified hydrogen water-vapor separator 13 is vertically arranged, a housing 131 is cylindrical, a humidified air or humidified hydrogen inlet 133 is arranged at the lower side part of the housing 131, a humid air or humid hydrogen (no liquid water) outlet 134 is arranged at the top part of the housing 131, a water outlet 135 is arranged at the bottom part of the housing 131, the water outlet 135 extends upwards to form an inverted trumpet shape, and a normally closed electromagnetic valve 136 is arranged on the water outlet 135 to control opening and drainage at regular time.

One end of the humidified air or hydrogen water-vapor separator 13 is communicated with the outlet end of the air humidifying device 12 or the hydrogen humidifying device 11, and the other end is communicated with the air inlet or the hydrogen inlet end of the fuel cell stack 1.

Referring to fig. 2, in this embodiment, the humidified air or hydrogen gas from the outlet end of the air humidifier 12 or the hydrogen humidifier 11 inevitably condenses some water droplets 122 or suspended water mass 123 after passing through a section of the pipe 121, the humidified air or hydrogen enters the inlet 133 of the humidified air or hydrogen of the water-vapor separator 13 of the present invention, and then passes through the first porous glass filter layer 132 from bottom to top, most of the water droplets 122 and all of the suspended water mass 123 are blocked, and only wet air or wet hydrogen gas passes through, the wet air or hydrogen passes through the second porous glass filter layer 132, where almost all of the liquid water is retained, and only the wet air or hydrogen consisting of water in vapor form and air or hydrogen passes through, the wet air or wet hydrogen gas enters the air or hydrogen inlet of the fuel cell stack 1 to react immediately after coming out of the wet air or wet hydrogen outlet 134. ,

example 2

Referring to fig. 3, a 1-200 KW fuel cell with high operation stability includes a fuel cell stack 1, a hydrogen storage device 2, a hydrogen pressure reducing valve 3, an air filtering device 4, an air compression supply device 5, a stack-out hydrogen water-vapor separator 6, a stack-out air water-vapor separator 6', a water tank 7, a cooling fluid circulation pump 8, a radiator 9, a hydrogen circulation pump 10, a hydrogen humidifying device 11, an air humidifying device 12, and a humidified air or hydrogen water-vapor separator 13.

The humidified air or hydrogen water-vapor separator 13 includes a housing 131, a three-layer filter layer 132 is provided in the housing 131, the filter layer 132 is made of a porous polytetrafluoroethylene film, and the rest of the structure is the same as that of example 1.

Referring to fig. 1 and 2, the present embodiment is applied to a case where the connecting pipe 121 between the outlet end of the air humidifier 12 or the hydrogen humidifier 11 and the air or hydrogen inlet of the fuel cell stack 1 is relatively long, and the generated water droplets 122 and the suspended water mass 123 are relatively large.

By analogy, four, five, and other embodiments of the filter layer 132 can be derived, and these embodiments are all within the scope of the present invention.

Claims

1. A fuel cell with high operation stability comprises a fuel cell stack, a hydrogen storage device, a hydrogen pressure reducing valve, a hydrogen humidifying device, an air filtering device, an air compression supply device, an air humidifying device, a pile hydrogen gas-steam separator, a hydrogen circulating pump, a pile air gas-steam separator, a water tank, a cooling fluid circulating pump and a radiator.

2. A fuel cell having improved operational stability according to claim 1 wherein said filter layer is two layers.

3. A fuel cell with high operation stability according to claim 1 or 2, wherein the filter layer is made of porous glass or a porous plastic material membrane.

4. The fuel cell of claim 1, wherein the humidified air or hydrogen water-vapor separator is vertically disposed, and has a humidified air or hydrogen inlet at a lower side of the housing, a humidified air or hydrogen outlet at a top of the housing, and a water outlet at a bottom of the housing, and the water outlet is provided with a normally closed solenoid valve for controlling timed water discharge.

5. The fuel cell of claim 4, wherein the water outlet extends upward in an inverted trumpet shape.

6. A fuel cell having increased operational stability according to claim 1, wherein said housing is cylindrical.