CN1527425A

CN1527425A - Fuel cell pile suitable for mass production and assembling

Info

Publication number: CN1527425A
Application number: CNA031156975A
Authority: CN
Inventors: 胡里清
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: State Grid Corp of China SGCC; Shanghai Municipal Electric Power Co; Shanghai Shenli Technology Co Ltd
Priority date: 2003-03-07
Filing date: 2003-03-07
Publication date: 2004-09-08
Anticipated expiration: 2023-03-07
Also published as: CN100517825C

Abstract

The fuel cell pile suitable for mass production and assembling includes guiding plate, porous diffusion layer material, membrane electrode, front end plate and back end plate. The guiding plate has porous diffusion layer material covering its one side, and the membrane electrode consists of proton exchange membrane and catalyst coated to two sides of the proton exchange membrane. Two opposite guiding plates and one membrane electrode in between are pressurized to laminate and front end plate and back end plate are set on two ends to constitute the fuel cell pile. Compared with available technology, the fuel cell pile of the present invention may be detached into three independent parts, including guide plate, porous diffusion layer material and membrane electrode, which may be mass produced to realize the large scale production of fuel cell pile.

Description

Fuel cell stack suitable for batch production and assembly

Technical Field

The present invention relates to a fuel cell stack, and more particularly, to a fuel cell stack suitable for mass production and assembly.

Background

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, 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 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 (MEA) is generally placed between two conductive plates, and the surface of each guiding plate in contact with the MEA is die-cast, stamped, or mechanically milled to form at least one or more guiding grooves. The guide electrode plates can be plates made of metal materials or plates made of graphite materials. The diversion pore canals and the diversion grooves on the diversion electrode 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 a current flow collection mother plate and mechanical supports at two sides of the membrane electrode, and 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 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 an upper end plate, a lower 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.

The proton exchange membrane fuel cell can be used as a power system of all vehicles, ships and other vehicles, and can also be used as a portable, movable and fixed power generation device. The pem fuel cell power generation system must include fuel cell stack, hydrogen supply, air supply, cooling, automatic control, and power output.

The key of the large-scale industrialized application of the proton exchange membrane fuel cell power generation system is to realize the large-scale production and assembly of the proton exchange membrane fuel cell stack, and the large-scale industrialization and assembly of each part of the auxiliary operation of other fuel cell stacks are easy to realize.

At present, a proton exchange membrane fuel cell stack is formed by overlapping a plurality of flow guide polar plates and a plurality of three-in-one electrodes, and then a complete fuel cell stack is assembled by a mother plate, a front end plate, a rear end plate and a fastener.

As shown in fig. 1, a fuel cell stack is formed by stacking a plurality of such single cells, as shown in fig. 2, in a typical fuel cell structure indicated in U.S. patent 5,863,673.

The guide plate, current mother plate, front and back ends and fasteners in fuel cell stack can be disassembled, but the most key parts of three-in-one electrode is a whole, and the part is pressed successfully by proton exchange membrane and two porous diffusion layer materials with catalyst on the inner surface through hot pressing process. During the large-scale fuel cell stack industrial production, the large-scale flow line production of the three-in-one electrode must be realized. At present, the production process of hot pressing of the proton exchange membrane and two porous diffusion layer materials with catalysts on the inner layer surfaces causes great difficulty and inconvenience to the large-scale flow line production of the three-in-one electrode:

(1) the flow-line production requires a roll-type porous diffusion layer material and the inner layer surface must already be coated with catalyst. However, theporous diffusion layer material is often a relatively brittle carbon paper material, which can be broken when formed into a roll form, and the catalyst is prone to falling off, particularly when the roll is formed after being coated with the catalyst.

(2) The production line of three-in-one electrode has to have a hot-pressing roller for accurately controlling temperature and pressure to ensure the performance consistency of each three-in-one electrode, and the implementation of the hot-pressing roller with high-precision temperature and pressure control is very difficult.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a fuel cell stack which is reasonable in structure, convenient to process and suitable for mass production and assembly.

The purpose of the invention can be realized by the following technical scheme: the utility model provides a fuel cell stack that is fit for batch production and assembly, includes guide plate, porotic diffusion layer material, membrane electrode, front end plate, rear end plate, its characterized in that, guide plate's guiding gutter one side cover and have one deck porotic diffusion layer material, the membrane electrode constitute by proton exchange membrane and this proton exchange membrane two sides coating catalyst layer, guide plate, porotic diffusion layer material and the proton exchange membrane's of taking the catalyst periphery be equipped with sealed elastomer, constitute the monocell with two relative guide plate intermediate lamination that cover porotic diffusion layer material a proton exchange membrane of taking the catalyst, coincide this monocell of multiunit to set up front end plate, rear end plate at both ends, constitute the fuel cell stack that is fit for batch production and assemblypromptly.

The porous diffusion layer is made of porous carbon paper or other porous materials, and a sealing elastomer is arranged on the periphery of the porous diffusion layer.

The sealing elastic body is sealing adhesive or sealing rubber.

The guide plate, the porous diffusion layer material and the proton exchange membrane with the catalyst are three independent assembly components.

The guide plate, the porous diffusion layer material and the proton exchange membrane with the catalyst of the fuel cell stack are three independent components which can be repeatedly disassembled and assembled and have better air tightness after being compressed or bonded, so the mass production and assembly of the fuel cell stack are the production and assembly of the guide plate, the porous diffusion layer material and the proton exchange membrane with the catalyst of the three independent components, thereby avoiding the hot-pressing production process of three-in-one electrodes and easily realizing the mass production and assembly of the fuel cell stack.

Drawings

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

FIG. 2 is a schematic diagram of a conventional fuel cell stack;

FIG. 3 is a schematic diagram of the structure of a single cell of a fuel cell stack according to the present invention;

figure 4 is a schematic diagram of the structure of a fuel cell stack baffle of the present invention;

FIG. 5 is a schematic structural diagram of a porous diffusion layer material of a fuel cell stack according to the present invention;

FIG. 6 is a schematic diagram of a fuel cell stack with a catalyzed PEM according to the present invention;

FIG. 7 is an exploded view of a fuel cell stack cell according to the present invention;

fig. 8 is an exploded view of a fuel cell stack according to the present invention.

Detailed Description

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

As shown in fig. 3, a fuel cell stack suitable for mass production and assembly includes a flow guide plate 1, porous carbon paper 2, a membrane electrode 3, a front end plate (not shown) and a rear end plate (not shown), one side of the flow guide groove 11 of the flow guide plate 1 is covered with a layer of porous carbon paper 2, the membrane electrode 3 is composed of a proton exchange membrane 31 and catalyst layers 32 coated on both sides of the proton exchange membrane, the peripheries of the flow guide plate 1, the porous carbon paper 2 and the proton exchange membrane 3 with catalyst are provided with a sealing elastic body 4, a single cell is formed by pressing and combining two opposite flow guide plates 1 covered with porous diffusion layer materials with a proton exchange membrane 3 with catalyst, a plurality of groups of single cells are stacked, and the front end plate and the rear end plate are provided at both ends, thus forming the fuel cell stack suitable for mass production and assembly.

The parts of the guide plate 1 except the dotted lines are coated with an elastomer or adhesive 4 with good air tightness, as shown in fig. 4, the carbon paper except the dotted lines of the porous carbon paper 2 is filled with the elastomer or adhesive 4 with good air tightness, as shown in fig. 5, the inner parts of the dotted lines of the proton exchange membranes 31 of the membrane electrodes 3 are coated with catalysts 32, the films except the dotted lines are coated with the elastomer or adhesive 4 with good air tightness, as shown in fig. 6, and the fuel cell stack single cell assembled by the components is shown in fig. 7; several such fuel cell stack cells may be assembled into a fuel cell stack as shown in fig. 8.

The fuel cell stack can be repeatedly and completely disassembled into three independent components, namely a guide plate 1, porous carbon paper 2 and a membrane electrode 3 (proton exchange membrane with catalyst), the fuel cell stack can be manufactured by carrying out water flowing assembly on a large number of the three components, and each independent component, namely the guide plate 1, the porous carbon paper 2 and the membrane electrode 3, can be independently processed in a large number, so that the large-scale industrial production of the fuel cell stack can be realized.

Claims

1. The utility model provides a fuel cell stack that is fit for batch production and assembly, includes guide plate, porotic diffusion layer material, membrane electrode, front end plate, rear end plate, its characterized in that, guide plate's guiding gutter one side cover and have one deck porotic diffusion layer material, the membrane electrode constitute by proton exchange membrane and this proton exchange membrane two sides coating catalyst layer, guide plate, porotic diffusion layer material and the proton exchange membrane's of taking the catalyst periphery be equipped with sealed elastomer, constitute the monocell with two relative guide plate intermediate lamination that cover porotic diffusion layer material a proton exchange membrane of taking the catalyst, coincide this monocell of multiunit to set up front end plate, rear end plate at both ends, constitute the fuel cell stack that is fit for batch production and assembly promptly.

2. The fuel cell stack of claim 1, wherein the porous diffusion layer is made of porous carbon paper or other porous material, and the periphery of the porous diffusion layer is provided with a sealing elastomer.

3. The fuel cell stack suitable for mass production and assembly according to claim 1, wherein the sealing elastomer is a sealing adhesive, or a sealing rubber.

4. The fuel cell stack of claim 1, wherein the fluidic plates, porous diffusion layer material, and catalyzed proton exchange membrane are three separate assemblies.