CN2735553Y

CN2735553Y - An improved fuel battery pack compressing arrangement

Info

Publication number: CN2735553Y
Application number: CNU2004200908687U
Authority: CN
Inventors: 夏建伟; 胡里清; 章波
Original assignee: Shanghai Shen Li High Tech Co Ltd
Current assignee: Shanghai Shenli Technology Co Ltd
Priority date: 2004-10-11
Filing date: 2004-10-11
Publication date: 2005-10-19
Anticipated expiration: 2014-10-11

Abstract

The utility model provides an improved fuel battery pack compressing apparatus, comprising at least a set of single batteries which is composed of a diversion polar plate and a proton exchanging membrane electrode, a front afflux master blank, a back afflux master blank, a jacket plate with uniformly ejected pressure, a front end plate, and a back end plate. The front and the back afflux master blanks are clamped on the both ends of a set of single batteries; the jacket plate with the uniformly ejected pressure is arranged between the afflux master blanks and the end plates; the front and the back end plates are clamped on the outer side of the front afflux master blank and the jacket plate with the uniformly ejected pressure; the front and the back end plates are provided with at least two pull rods, the both ends of which are provided with a fastening cap nut; through regulating the fastening cap nut, the front and the back end plates are compacted, and thus the fuel battery pile is fastened. Compared with the prior art, the utility model has the advantages of uniform pressure, etc.

Description

Improved fuel cell stack pressing device

Technical Field

The utility model relates to a fuel cell especially relates to an improved generation fuel cell stack closing device.

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 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:

anodeReaction:

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 and 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 portable, movable and fixed power generation device.

Proton exchange membrane fuel cells are generally assembled by several single cells in series or parallel to form a fuel cell stack.

Fig. 1 shows a flow guide plate in a single cell of a conventional fuel cell, which includes an air inlet 1a, a water inlet 2a, a hydrogen inlet 3a, a flow channel 4a, an air outlet 5a, a water outlet 6a, and a hydrogen outlet 7 a; fig. 2 is a three-in-one membrane electrode in a single cell of a conventional fuel cell, which includes an air inlet 1a, a water inlet 2a, a hydrogen inlet 3a, an electrode active region 8a, an air outlet 5a, a water outlet 6a, and a hydrogen outlet 7 a; fig. 3 shows a conventional fuel cell stack, which includes a fuel cell stack 9a, collector motherboards 10a, 10b, end plates 11a, 11b, metal tie rods 12a, and nuts 13 a.

The existing fuel cell stack is generally composed of a plurality of monocells (the monocells are composed of a flow guide polar plate and a three-in-one membrane electrode), a front end plate and a rear end plate of a flow collection motherboard are assembled, a plurality of pull rods are arranged on the front end plate and the rear end plate, and the front end plate and the rear end plate are compressed into a fuel cell stack by using fasteners generally; the fastener tie-rod plus screw method is the usual fastening method.

The fuel cell stack must be fully compressed by the fasteners, but must be uniformly compressed within a certain proper pressure range, so as to ensure the safe and efficient operation of the fuel cell stack.

Currently, the conventional fastening method using tie rods has the following technical drawbacks:

1. the requirement for fastening and assembling the tie rods of the fuel cell stack is particularly high, and it is necessary to achieve that each area on the front end plate and the rear end plate of the whole fuel cell stack is subjected to basically consistent and same fastening force, which is very difficult, and practical operation often causes that a certain area on the front end plate and the rear end plate of the whole fuel cell stack is subjected to smaller fastening force, and a certain area is subjected to larger fastening force, so that certain areas on the fuel cell polar plates are subjected to insufficient pressing force, so that the contact resistance of the electrodes and the guide polar plates is too large, and the pressing force of certain areas is too large, so that the polar plates are deformed or cracked, or the electrodes are damaged.

2. When the fuel cell stack is tightly assembled by the pull rod, when the fuel cell expands or contracts due to heat, the front end plate and the rear end plate of the fuel cell stack are stressed differently, and the pole plates or the electrodes can be damaged in serious cases.

Further, Chinese patent (patent No. 97228898.8, 1999) discloses a fuel cell stack having rubber cushions placed inside the pressure plates. Chinese patent No. 02265903.X discloses another fuel cell stack with uniform fastening pressure, which is characterized in that an air cushion bag is arranged in front of an end plate of the fuel cell stack, and the air cushion bag is inflated to reach 2-5 atmospheric pressures, so that each area of an electrode plate of the fastened fuel cell stack bears uniform fastening pressure. The above two patent technologies also have the following technical defects:

1. the first technique employs rubber cushions to secure the front and rear end plates of the fuel cell stack. In fact, the rubber plate will deform greatly after receiving the fastening pressure, and the deformation will also be larger in the area where the fastening pressure is larger. Over time, the regions with large deformation are likely to age, lose elasticity first, and finally, the fastening force applied to each region of the electrode and the polar plate of the fuel cell stack is not uniform.

2. The second patent technology needs an air cushion bag, which is inconvenient to manufacture and inflate, and is easy to cause accidents such as air leakage after inflation.

SUMMERY OF THE UTILITY MODEL

The present invention is directed to overcoming the above-mentioned deficiencies of the prior art and providing an improved fuel cell stack compression device with uniform pressure.

The purpose of the utility model can be realized through the following technical scheme: an improved fuel cell stack compressing device comprises at least one group of monocells formed by a flow guide polar plate and a proton exchange membrane electrode, a front collecting mother plate, a rear collecting mother plate, a front end plate and a rear end plate, wherein the front collecting mother plate and the rear collecting mother plate are clamped at two ends of the at least one group of monocells, the front end plate and the rear end plate are clamped at two outer sides of the front collecting mother plate and the rear collecting mother plate, at least two pull rods are arranged on the front end plate and the rear end plate, fastening nuts are arranged at two ends of each pull rod, the front end plate and the rear end plate are compressed through adjusting the fastening nuts, and therefore a fuel cell stack is fastened.

The pressure uniform ejection jacket plate comprises an inner clamping plate and springs, one surface of the inner clamping plate is tightly attached to the flow collection mother plate, and a plurality of springs are uniformly distributed on the other surface of the inner clamping plate.

One side of the inner clamping plate, which is close to the spring, is provided with a plurality of concave rings, and the spring is arranged in the concave rings.

The inner clamping plate can be plastic with little deformation or rubber plate with high hardness and difficult aging.

The inner side of the end plate is provided with a plurality of concave rings for the spring to be arranged.

The end plate is a metal plate.

The pressure uniform popping jacket plate comprises an inner clamping plate, springs and an outer clamping plate, one surface of the inner clamping plate is tightly attached to the flow collecting mother plate, the other surface of the inner clamping plate is uniformly provided with the plurality of springs, one surface of the outer clamping plate is tightly attached to the springs, and the other surface of the outer clamping plate is tightly attached to the end plate.

And a plurality of concave rings for the spring to be arranged are arranged on one surfaces of the inner clamping plate and the outer clamping plate, which are close to the spring.

The four pull rods are respectively arranged at the four corners of the front end plate and the rear end plate in a penetrating way.

And a gasket is arranged between the fastening nut and the end plate.

The utility model discloses owing to adopted above technical scheme, set up a pressure promptly and evenly popped out the clamp cover at fuel cell pile (as figure 4), consequently the utility model discloses can compensate fuel cell pile because of the inconsistent inhomogeneous defect of end plate atress that leads to of each pull rod pulling force when the assembly, make polar plate and electrode atress more even to the normal operating of fuel cell pile has been ensured and its life can be improved.

Drawings

FIG. 1 is a schematic structural diagram of a current-guiding plate of a fuel cell stack;

FIG. 2 is a schematic structural diagram of a three-in-one membrane electrode of a conventional fuel cell stack;

FIG. 3 is a schematic diagram of a conventional fuel cell stack;

FIG. 4 is a schematic structural view of the present invention;

fig. 5 is a schematic structural view of the spring-loaded surface of the inner clamping plate of the uniform pressure ejection clamp sleeve of the present invention;

fig. 6 is a schematic diagram of the structure of the outer splint (end plate) against the spring surface of the uniform pressure ejection clamp sleeve of the present invention;

fig. 7 is a schematic structural view of the pressure-equalizing pop-up jacket of the present invention.

In the drawings:

314, 341: placing a spring concave ring (concave round hole);

31:an inner clamping plate with a uniform pressure ejection jacket;

34: an outer clamping plate with a pressure uniform ejection jacket, which is also used as a rear end plate of the fuel cell stack;

32: a spring;

342: a pull rod hole.

Detailed Description

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

Examples

As shown in fig. 4, a fuel cell stack compressing apparatus with uniform fastening pressure comprises a plurality of groups of single cells 1 composed of guide plate and proton exchange membrane electrode, front and rear current collecting mother plates 2, a pressure uniform ejecting jacket 3, a front end plate 4, a rear end plate 34; the front and rear current collecting mother boards 2 are clamped at two ends of a plurality of groups of single batteries 1; the pressure-equalizing ejection jacket 3 is approximately in the shape of a flow guide plate and a rear end plate 34 of the fuel cell stack 1 (in the embodiment, the shape is approximately square), the pressure-equalizing ejection jacket 3 is clamped between the rear current collecting mother plate 2 and the rear end plate 34 (as shown in fig. 7), and the rear end plate 34 also has an outer clamping plate with the pressure-equalizing ejection jacket 3.

The front end plate 34 and the rear end plate 34 are respectively clamped outside the front collecting mother plate 2 and the ejection jacket 3 with uniform pressure; four pull rods 5 are arranged at four corners of the front end plate 34 and the rear end plate 34 in a penetrating manner (two pull rods can be arranged, the two pull rods are respectively arranged in the middle of the left side and the rightside or in the middle of the upper side and the lower side of the front end plate and the rear end plate in a penetrating manner so as to ensure pressure balance), fastening nuts 6 are arranged at two ends of each pull rod 5, gaskets 7 are arranged between the fastening nuts 6 and the end plates 4, the front end plate and the rear end plate 4 are tightly pressed by adjusting the fastening nuts 6, and therefore the fuel cell stack 1 is fastened.

In the above embodiments, the height and width dimensions of the fuel cell plates and electrodes are 206mm and 206mm, respectively, as shown in fig. 5-7. The ejection collet 3 with uniform pressure therein is composed of an inner clamping plate 31 and an outer clamping plate (rear end plate) 34, wherein the outer clamping plate doubles as the fuel cell stack rear end plate. The fuel cell stack has 100 individual cells with dimensions of 206mm x 450mm, the inner clamping plate dimensions of the clamping sleeve plate of 206mm x 8mm and the rear end plate dimensions of 210mm x 245mm x 6mm, a total of 25 springs are used, each spring having a length of about 3cm and generating a force of about 50 kg when each spring is contracted by 1cm, so that the whole clamping sleeve generates a force of 1250 kg. When the tie rods are tightened, the entire jacket is tightened 1cm and a uniform spring-out pressure is applied to the collector mother plate and all the electrodes and plates on the fuel cell stack.

Claims

1. An improved fuel cell stack compressing device comprises at least one group of monocells formed by a flow guide polar plate and a proton exchange membrane electrode, a front collecting mother plate, a rear collecting mother plate, a front end plate and a rear end plate, wherein the front collecting mother plate and the rear collecting mother plate are clamped at two ends of the at least one group of monocells, the front end plate and the rear end plate are clamped at two outer sides of the front collecting mother plate and the rear collecting mother plate, at least two pull rods are arranged on the front end plate and the rear end plate, fastening nuts are arranged at two ends of each pull rod, the front end plate and the rear end plate are compressed through adjusting the fastening nuts, and therefore a fuel cell stack is fastened.

2. An improved fuel cell stack compressing device as claimed in claim 1, wherein the pressure-equalizing ejection jacket plate comprises an inner clamping plate and a plurality of springs, one surface of the inner clamping plate is tightly attached to the current-collecting mother plate, and the other surface of the inner clamping plate is uniformly provided with a plurality of springs.

3. An improved fuel cell stack compression device as claimed in claim 2, wherein the spring-loaded side of said inner clamp plate is provided with a plurality of recessed rings in which said springs are disposed.

4. An improved fuel cell stack compression device as in claim 3, wherein said inner clamping plate is a slightly deformable plastic or a harder, less aging-resistant rubber plate.

5. An improved fuel cell stack compression device as in claim 1, 2, 3 or 4, wherein the end plate is provided with a plurality of spring receiving pockets on the inside.

6. An improved fuel cell stack compression device as in claim 5, wherein the end plate is a metal plate.

7. An improved fuel cell stack compressing device as claimed inclaim 1, wherein the pressure-uniform ejection jacket plate comprises an inner clamping plate, a spring, and an outer clamping plate, one surface of the inner clamping plate is tightly attached to the current-collecting mother plate, the other surface of the inner clamping plate is uniformly provided with a plurality of springs, one surface of the outer clamping plate is tightly attached to the spring, and the other surface of the outer clamping plate is tightly attached to the end plate.

8. An improved fuel cell stack compression device as claimed in claim 7, wherein the inner and outer clamps have a plurality of recessed rings on the sides thereof that are adjacent to the springs.

9. The improved fuel cell stack pressing device according to claim 1, wherein the four tie rods are respectively inserted into four corners of the front and rear end plates.

10. An improved fuel cell stack compression device as in claim 1, wherein a washer is disposed between the clamping nut and the end plate.