CN2491969Y

CN2491969Y - Baffler able to increase fuel battery work properties

Info

Publication number: CN2491969Y
Application number: CN01246227U
Authority: CN
Inventors: 胡里清
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: Shanghai Shenli Technology Co Ltd
Priority date: 2001-06-29
Filing date: 2001-06-29
Publication date: 2002-05-15
Anticipated expiration: 2011-06-29

Abstract

The utility model relates to a deflector which can promote the operation performance of the fuel batteries, which comprises a deflector body, a deflecting slot arranged on the deflector body, and an air inlet and an air outlet communicating with the deflecting slot, wherein the air inlet and the air outlet are arranged on the upper end and the lower end of the deflector body, and the air inlet which is arranged on the upper end or the lower end of the deflector body passes through at least on deflecting slot and is communicated with the air outlet which is arranged on the lower end or the upper end of the deflector body. The fuel batteries which adopt the deflector has excellent battery humidification performance, compact structure, and low cost.

Description

Guide plate capable of improving working performance of fuel cell

The utility model relates to a can improve fuel cell working property's guide plate.

An electrochemical fuel cell is a device that is capable of converting hydrogen fuel 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, suchas 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 end react 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 Assembly (MEA) is typically placed between two conductive plates, and the surface of each conductive plate in contact with the MEA is die-cast, stamped, or mechanically milled to form at least one or more channels. The conductive plates can be plates made of metal materials or plates made of graphite materials. The flow guide pore canals and the flow guide grooves on the conductive 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 arranged, and a flow guide polar plate of anode fuel and a flow guide polar plate of cathode oxidant are respectively arranged on two sides of the membrane electrode. The flow guide polar plates are used as current collector plates and mechanical supports at two sides of the membrane electrode, and the flow guide grooves on the flow guide polar 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 canbe 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) cooling fluid (such as water) is uniformly distributed into cooling channels in each battery pack through an inlet and an outlet of the cooling fluid and a flow guide channel, and heat generated by 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.

In order to make the pem fuel cell operate in a high performance state, it is necessary to keep the pem in a state of humidification and no water loss. Because the protons need to be hydrated when passing through the proton exchange membrane and the hydrated protons carry a lot of water molecules when passing through the proton exchange membrane, if the proton exchange membrane is in a dehydrated dry state, the resistance of the protons when passing through the proton exchange membrane is large, which means that the working performance in the fuel cell is reduced and the current can not be output when the performance is serious.

In order to keep the proton exchange membrane in the proton exchange membrane fuel cell in a non-dehydrated state or in a humidified state, the following technologies are available:

1. external humidification technology: the fuel hydrogen and oxidant such as oxygen and air are humidified firstly, so that the fuel hydrogen and oxidant gas contain certain water vapor (reach certain relative humidity), and then enter the fuel cell for reaction, such as: as described in us patent 6,106,964 (8 months 2000).

2. Internal humidification technology: the basic principle of the internal humidification technology is the same as that of the external humidification, but the fuel cell stack is divided into a humidification section and an active section, and two stages are fused in one cell stack to enhance the compactness of the cell and improve the energy utilization efficiency. Thus, the fuel hydrogen and the oxidant air are humidified firstly through the humidifying section of the cell stack and then enter the active section of the cell stack for reaction.

However, both of the above techniques have the following disadvantages:

the first technique additionally adds an external humidifying device of the fuel cell, which not only additionally increases the weight and volume of the peripheral system of the fuel cell, but also wastes a large amount of material and labor cost.

The second technique has similar disadvantages in that although the overall compactness is higher than that of the first technique, the volume and weight of the entire stack are increased, and a large amount of manufacturing materials and labor costs are wasted.

The utility model aims to overcome the defects of the prior art and provide a guide plate capable of improving the working performance of a fuel cell, and the fuel cell made by the guide plate has good humidifying performance, compact structure and lower cost.

The purpose of the utility model can be realized through the following technical scheme: the utility model provides a can improve guide plate of fuel cell working property, includes the guide plate body, establishes the guiding gutter on this guide plate body, with the gas inlet and the gas outlet of this guiding gutter intercommunication, its characteristics are, gas inlet establish the upper and lower both ends at the guide plate body, gas outlet also establish the upper and lower both ends at the guide plate body, establish the gas inlet of guide plate body upper end through at least one guiding gutter with establish the gas outlet intercommunication at the guide plate body lower extreme, establish the gas inlet of guide plate body lower extreme also through at least one guiding gutter with establish the gas outlet intercommunication at the guide plate body upper end.

The gas inlet is an oxidant gas inlet or a fuel hydrogen inlet.

The oxidant gas inlet is an oxygen or air inlet.

The utility model discloses owing to adopted above technical scheme, make fuel hydrogen or oxidant (oxygen, air) can admit air at two imports simultaneously, nevertheless according to reverse walking on the guide plate, can merge unified giving vent to anger at last, this kind of reverse walking has following advantage:

the first path of gas is in a dry state when entering the electrode, so that water in a proton exchange membrane in the electrode is easy to take away; along with the electrochemical reaction, a large amount of water is generatedinto the lower half part of the dewetting membrane when reaching the middle part and the lower half part of the electrode; the second path of gas is just opposite, enters the electrode from the lower half part of the electrode and is in a dry state when entering the electrode, water in the membrane in the electrode is easy to be taken away, and a large amount of water generates the upper half part of the humidifying removing membrane when reaching the middle part and the upper half part of the electrode along with the generation of electrochemical reaction, so that the proton exchange membrane is always humidified, and the performance of the fuel cell is kept in a better state.

Fig. 1 is a schematic structural diagram of embodiment 1 of the present invention;

fig. 2 is a schematic structural diagram of embodiment 2 of the present invention.

The present invention will be further described with reference to the accompanying drawings and specific embodiments.

Example 1

Referring to fig. 1, a (hydrogen) flow guiding plate capable of improving the working performance of a fuel cell includes a flow guiding plate body 1, flow guiding grooves 2 disposed on the flow guiding plate body 1, and a hydrogen inlet a and a hydrogen outlet B communicated with the flow guiding grooves 2, wherein the hydrogen inlet a is disposed at the upper and lower ends of the flow guiding plate body 1, the hydrogen outlet B is also disposed at the upper and lower ends of the flow guiding plate body 1, the hydrogen inlet a disposed at the upper end of the flow guiding plate body 1 is communicated with the hydrogen outlet B disposed at the lower end of the flow guiding plate body 1 through the two flow guiding grooves 2, and the hydrogeninlet a disposed at the lower end of the flow guiding plate body 1 is also communicated with the hydrogen outlet B disposed at the upper end of the flow guiding plate body 1 through the two flow. Hydrogen coming from a hydrogen inlet A at the upper end of the flow guide plate body is called a first path of hydrogen, hydrogen coming from a hydrogen inlet A at the lower end of the flow guide plate body is called a second path of hydrogen, the first path of hydrogen and the second path of hydrogen travel along respective flow guide grooves in a relatively reverse direction and then respectively go out from hydrogen outlets B at the upper end and the lower end of the flow guide plate body, the hydrogen coming from the hydrogen inlets at the upper end and the lower end of the flow guide plate body come from the same gas source Q to be uniformly fed, and the hydrogen going out from the hydrogen outlets at the upper end and the lower end of the; the hydrogen coming from the hydrogen inlet at the upper end of the guide plate body is in a dry state when entering the electrode, so that water in a proton exchange membrane in the electrode is easy to take away, a large amount of water is generated when the hydrogen reaches the middle part and the lower part of the electrode along with the occurrence of electrochemical reaction, so that the lower part of the proton exchange membrane is humidified, the hydrogen coming from the hydrogen inlet at the lower end of the guide plate body is also in a dry state when entering the electrode, so that the water in the proton exchange membrane in the electrode is easy to take away, a large amount of water is generated when the hydrogen reaches the middle part and the upper part of the electrode along with the occurrence of electrochemical reaction, so that the upper part of the proton exchange membrane is humidified, the comprehensive effect enables the whole proton exchange membrane to be in a uniform water distribution state, and the.

Example 2

Referring to fig. 2, a flow guide plate (air) capable of improving the working performance of a fuel cell includes a flow guide plate body 1, flow guide grooves 2 formed on the flow guide plate body 1, and an air inlet a and an air outlet B communicated with the flow guide grooves 2, the air inlet a is formed at the upper and lower ends of the flow guide plate body 1, the air outlet B is also formed at the upper and lower ends of the flow guide plate body 1, the air inlet a formed at the upper end of the flow guide plate body 1 is communicated with the air outlet B formed at the lower end of the flow guide plate body 1 through three flow guide grooves 2, and the air inlet a formed at the lower end of the flow guide plate body 1 is also communicated with the air outlet B formed at the upper end of the flow guide plate body 1 through three flow guide grooves 2. The air coming from the air inlet A at the upper end of the air deflector body is called a first path of air, the air coming from the air inlet A at the lower end of the air deflector body is called a second path of air, the first path of air and the second path of air travel along respective guide grooves in a relatively reverse direction and then respectively go out from the air outlets B at the upper end and the lower end of the air deflector body, the air coming from the air inlets at the upper end and the lower end of the air deflector body comes from a same air source Q to be uniformly fed, and the air going out from the air outlets at the upper end and the lower end of the air deflector; the air coming from the air inlet A at the upper end of the guide plate body is in a dry state when entering the electrode, so that water in a proton exchange membrane in the electrode is easy to take away, along with the occurrence of electrochemical reaction, a large amount of water is generated when the air reaches the middle part and the lower part of the electrode, so that the lower part of the proton exchange membrane is humidified, the air coming from the air inlet A at the lower end of the guide plate body is also in a dry state when entering the electrode, so that the water in the proton exchange membrane in the electrode is easy to take away, along with the occurrence of electrochemical reaction, a large amount of water is generated when the air reaches the middle part and the upper part of the electrode, so that the upper part of the proton exchange membrane is humidified, and the comprehensive effect ensures that the whole proton exchange membrane is in a uniform water distribution state.

Claims

1. The utility model provides a can improve fuel cell working property's guide plate, includes the guide plate body, establishes the guiding gutter on this guide plate body, with the gas inlet and the gas outlet of this guiding gutter intercommunication, its characterized in that, gas inlet establish the upper and lower both ends at the guide plate body, gas outlet also establish the upper and lower both ends at the guide plate body, establish the gas inlet of guide plate body upper end through at least one guiding gutter with establish the gas outlet intercommunication at the guide plate body lower extreme, establish the gas inlet at the guide plate body lower extreme also through at least one guiding gutter with establish the gas outlet intercommunication in the guide plate body upper end.

2. The fluidic plate for improving the operating performance of a fuel cell according to claim 1, wherein the gas inlet is an oxidant gas inlet or a fuel hydrogen inlet.

3. A flow guide plate for improving the operating performance of a fuel cell as claimed in claim 2, wherein the oxidant gas inlet is an oxygen or air inlet.