CN101241994A - Method for improving contact between bipolar plate of flat plate type fuel cell and proton exchange membrane - Google Patents

Abstract

The invention relates to a method for improving the contact between a bipolar plate and a proton exchange membrane of a flat plate type fuel cell. The invention utilizes the thickness variation of the metal layers on the upper and lower surfaces of the bipolar plate and provides a conductive raised structure and other methods to solve the problem of poor contact when the bipolar plate is pressed with the proton exchange membrane.

Description

Method for Improving Contact Between Bipolar Plate and Proton Exchange Membrane of Flat Fuel Cell

The present invention is a divisional application with the application number 200410074771.1, the filing date is September 14, 2004, and the title of the invention is "Method for Improving Contact between Bipolar Plate and Proton Exchange Membrane of Flat Fuel Cell".

technical field

The invention relates to a flat fuel cell, in particular to a method for improving the contact between the bipolar electrode plate (or bipolar plate, bipolar plate) of the flat fuel cell and the proton exchange membrane.

Background technique

Direct Methanol Fuel Cell (DMFC) is a power generation device that uses liquid dilute methanol aqueous solution or pure methanol as fuel to convert chemical energy into electricity through an electrochemical process. Compared with traditional power generation methods, direct methanol fuel cells have the advantages of low pollution, low noise, high energy density, and high energy conversion efficiency. Products, vehicles, military equipment, space industry, etc.

The operating principle of the direct methanol fuel cell is that the methanol aqueous solution is oxidized on the anode catalyst layer to generate hydrogen ions (H ⁺ ), electrons (e ^- ) and carbon dioxide (CO ₂ ), in which the hydrogen ions are transferred to the cathode through the electrolyte, and the electrons It is transmitted to the load through an external circuit and then transmitted to the cathode. At this time, the oxygen supplied to the cathode will undergo a reduction reaction with hydrogen ions and electrons in the cathode catalyst layer to produce water.

Fuel cells are generally composed of several basic units. Since the voltage that each basic unit can provide is relatively small, many basic units must be connected in series in order to achieve the required operating voltage output.

Contents of the invention

The main purpose of the present invention is to provide a method for improving the contact between the bipolar plate and the proton exchange membrane of the flat fuel cell, so as to solve the disadvantages of the prior art.

In order to achieve the above object, the present invention provides a method for improving the contact between the bipolar plate of the flat fuel cell and the proton exchange membrane, comprising the following steps:

Provide a first bipolar plate, a proton exchange membrane member, a second bipolar plate and at least one junction piece, wherein the proton exchange membrane member is placed on the first bipolar plate, and the junction piece has a The opening of the membrane, and the second bipolar plate is placed on the proton exchange membrane, wherein the first bipolar plate has a first proton exchange surface in contact with the proton exchange membrane and a fuel surface contacting the fuel, the second The bipolar plate has a second proton exchange surface in contact with the proton exchange membrane and an air surface in contact with air, wherein the fuel surface is provided with a first metal layer, the first proton exchange surface is provided with a second metal layer, the A third metal layer is provided on the second proton exchange surface and a fourth metal layer is provided on the air surface, wherein the thickness of the second metal layer is greater than the thickness of the first metal layer, and the thickness of the third metal layer is greater than the thickness of the the thickness of the fourth metal layer;

Wherein, the first bipolar plate includes a first substrate on which the first metal layer and the second metal layer are formed; the second bipolar plate includes a second substrate on which the third metal layer and the second metal layer are formed. The fourth metal layer; the proton exchange membrane in the proton exchange membrane is a solid proton exchange membrane;

Then press the first bipolar plate, the proton exchange membrane element, the second bipolar plate and the joining piece to form a bipolar plate/proton exchange membrane assembly.

The present invention provides another method for improving the contact between the bipolar plate and the proton exchange membrane of a flat fuel cell, comprising the following steps, providing a bipolar plate and a proton exchange membrane, wherein the bipolar plate includes at least one electrode region The proton exchange membrane is to be placed on the electrode area of the bipolar plate, a plurality of conductive protrusion structures are provided on the electrode area, and the proton exchange membrane is in contact with the plurality of conductive protrusion structures.

Description of drawings

Fig. 1 shows the schematic diagram of the bipolar plate/proton exchange membrane assembly of the planar fuel cell of prior art;

Fig. 2 shows the schematic diagram after pressing the bipolar plate/proton exchange membrane assembly of the flat fuel cell of the prior art;

Fig. 3 shows the schematic diagram of the bipolar plate/proton exchange membrane assembly of the planar fuel cell of preferred embodiment of the present invention;

Fig. 4 shows the schematic diagram after pressing the bipolar plate/proton exchange membrane assembly of the flat fuel cell of the preferred embodiment of the present invention;

Fig. 5 shows the schematic diagram of the bipolar plate/proton exchange membrane assembly of the flat fuel cell of another preferred embodiment of the present invention;

FIG. 6 shows a schematic diagram of a bipolar plate/proton exchange membrane assembly of a flat-plate battery according to another preferred embodiment of the present invention after lamination.

Symbol Description:

300 bipolar plate/proton exchange membrane module 320 first bipolar plate

322 first substrate 324 first metal layer

326 second metal layer 330 bonding piece

340 Proton Exchange Membrane 350 Second Bipolar Plate

352 second substrate 354 third metal layer

356 fourth metal layer 400 bipolar plate/proton exchange membrane module

420 first bipolar plate 422 first substrate

424 first metal layer 426 second metal layer

430 splicing piece 440 proton exchange membrane

450 second bipolar plate 452 second substrate

454 third metal layer 456 fourth metal layer

500 bipolar plate/proton exchange membrane module 520 first bipolar plate

522 first substrate 524 electrode area

526 lower surface 528 conductive raised structure

530 bonding piece 540 proton exchange membrane

550 second bipolar plate 552 second substrate

554 electrode area 556 upper surface

558 conductive bump structure

Detailed ways

Please refer to FIG. 1 and FIG. 2 . FIG. 1 and FIG. 2 respectively show schematic diagrams before and after lamination of the bipolar plate and the proton exchange membrane of the flat fuel cell. As shown in Figure 1, the bipolar plate/proton exchange membrane assembly 300 of flat fuel cell comprises the first bipolar plate (Bipolar Plate) 320, at least one bonding sheet (Bonding sheet) 330, a proton exchange membrane ( Membrane Electrode Assembly, Membrane Electrode Assembly, MEA) 340 and a second bipolar plate (BipolarPlate) 350. Wherein, the first bipolar plate 320 includes a first substrate 322, a first metal layer 324 covering the upper surface of the first substrate 322 and a second metal layer 326 on the lower surface, and the second bipolar plate 350 includes a The second substrate 352 , the third metal layer 354 covering the upper surface of the second substrate, and the fourth metal layer 356 covering the lower surface of the second substrate, wherein the metal layers mentioned above have the same thickness. The aforementioned first metal layer 324 , second metal layer 326 , third metal layer 354 and fourth metal layer 356 may be composed of a metal copper layer.

Then carry out the pressing process, as shown in Figure 2, wherein the second metal layer 326 and the third metal layer 354 are in contact with the proton exchange membrane member 340, but due to the influence of the stress of the metal layer, the second metal layer 326 and the third metal layer Between the layer 354 and the proton exchange membrane member 340 there is a gap and poor adhesion, and even the proton exchange membrane member 340 is not uniform in thickness due to different degrees of pressure, ripples are generated on the surface, and expansion or contraction is caused by heating or cooling. Separation of bipolar plates, etc. occurs. Due to the phenomena that occur after the aforementioned bipolar plate/proton exchange membrane module 300 is pressed together, the process cost increases and the yield rate decreases.

Therefore, the present invention provides a manufacturing method for improving the contact between the bipolar plate and the proton exchange membrane of the flat fuel cell, so as to solve the aforementioned problems.

Please refer to FIG. 3 and FIG. 4 . FIG. 3 and FIG. 4 show a manufacturing method for improving the contact between the bipolar plate and the proton exchange membrane of a flat fuel cell according to a preferred embodiment of the present invention. As shown in Figure 3, the bipolar plate/proton exchange membrane assembly 400 of the planar fuel cell comprises a first bipolar plate (BipolarPlate) 420, at least one bonding sheet (Bonding sheet) 430, a proton exchange membrane (membrane electrode) Components, Membrane Electrode Assembly, MEA) 440 and a second bipolar plate (Bipolar Plate) 450. Wherein, the first bipolar plate 420 includes a first substrate 422 with a first metal layer 424 on its upper surface and a second metal layer 426 on its lower surface, and the second bipolar plate 450 includes a second substrate 452, A third metal layer 454 is provided on the upper surface and a fourth metal layer 456 is provided on the lower surface. The aforementioned first metal layer 424 , second metal layer 426 , third metal layer 454 and fourth metal layer 456 may be composed of a metal copper layer. Wherein, the thickness of the second metal layer 426 is greater than the thickness of the first metal layer 424, the thickness of the third metal layer 454 is greater than the thickness of the fourth metal layer 456, and the first substrate 422 and the second substrate 452 can be glass fiber reinforced high Molecular material (Glass Fiber Reinforced Polymeric Material), such as ANSI grade FR-1, FR-2, FR-3, FR-4, FR-5, CEM-1 or CEM-3, etc., and proton The proton exchange membrane in the exchange membrane can be used such as DuPont's Nafion proton exchange membrane, or other solid proton exchange membranes with the same function. In addition, the bonding piece can be part of the polymerization stage (B-stage) used in the double circuit board process. "PREPREG" resin film and other materials.

Then a pressing process is performed. As shown in FIG. 4 , the first bipolar plate 420 , the proton exchange membrane element 440 , the second bipolar plate 450 and the bonding piece 430 are pressed together to form the bipolar plate/proton exchange membrane assembly 400 .

Please refer to FIG. 5 and FIG. 6 . FIG. 5 and FIG. 6 show another preferred embodiment of the present invention, a manufacturing method for improving the contact between the bipolar plate and the proton exchange membrane of the flat fuel cell. As shown in Figure 5, the bipolar plate/proton exchange membrane assembly 500 of the flat fuel cell comprises a first bipolar plate (Bipolar Plate) 520, at least one bonding sheet (Bonding sheet) 530, a proton exchange membrane (membrane) Electrode assembly, Membrane Electrode Assembly, MEA) 540 and a second bipolar plate (Bipolar Plate) 550. The first bipolar plate 520 includes a first substrate 522 and at least one electrode region 524, and then provides a plurality of conductive bump structures 528 on the lower surface 526 of the electrode region 524, and the second bipolar plate 550 includes The second substrate 552 and at least one electrode region 554 are provided with a plurality of conductive protrusion structures 558 on the upper surface 556 of the electrode region 554 . Wherein, the conductive protruding structures 528, 558 can be made of tin, lead, tin-lead or copper, and the outermost layer is covered with a gold-plated layer, and the height of the conductive protruding structures 528, 558 can be greater than 0.1 mm. The proton exchange membrane element 540 is intended to be placed between the electrode area 524 of the first bipolar plate 520 and the electrode area 554 of the second bipolar plate 550 . Wherein the first substrate 522 and the second substrate 552 can be made of glass fiber reinforced polymer material (Glass Fiber Reinforced Polymeric Material), such as ANSI grade FR-1, FR-2, FR-3, FR-4, FR- 5. Composed of CEM-1 or CEM-3, etc. In addition, the proton exchange membrane in the proton exchange membrane can be used such as DuPont Nafion proton exchange membrane, or other solid proton exchange membranes with the same function, and the joint piece can be Due to the partial polymerization stage (B-stage) "PREPREG" resin film and other materials used in the double circuit board process.

Then a pressing process is performed. As shown in FIG. 6 , the first bipolar plate 520 , the proton exchange membrane element 540 , the second bipolar plate 550 and the bonding sheet 530 are pressed together to form the bipolar plate/proton exchange membrane assembly 500 .

In summary, compared with the prior art, the method for improving the contact between the bipolar plate and the proton exchange membrane of the flat fuel cell of the present invention at least includes the following advantages:

The bipolar plate of the flat fuel cell adopts upper and lower metal layers of different thicknesses or adopts a conductive convex structure on the surface of the electrode area facing the proton exchange membrane unit, which can not only reduce the uneven thickness of the proton exchange membrane unit itself, but also The thickness will be reduced after lamination, so that the bipolar plate and the proton exchange membrane unit cannot be fully contacted, and the proton exchange membrane unit can also be properly pressured to increase the power generation.

Claims (7)

1. A method for improving the contact between a double-electrode plate of a flat fuel cell and a proton exchange membrane, comprising: providing a bipolar plate and a proton exchange membrane element, wherein the bipolar plate includes at least one electrode region, and the proton exchange membrane element is to be placed on the electrode region of the bipolar plate; providing a plurality of conductive protrusion structures on the electrode area; The proton exchange membrane is in contact with the plurality of conductive protrusion structures. 2. A method for improving the contact between the double-electrode plate and the proton exchange membrane of a flat fuel cell according to claim 1, wherein the height of the plurality of conductive protrusion structures is not less than 0.1 mm. 3. A method for improving the contact between the double-electrode plate and the proton exchange membrane of a flat fuel cell according to claim 1, wherein the conductive protrusion structure is made of materials including tin, lead, and tin-lead. 4. A method for improving the contact between the double-electrode plate of the flat fuel cell and the proton exchange membrane according to claim 1, wherein the proton exchange membrane in the proton exchange membrane is a solid proton exchange membrane. 5. A method for improving the contact between a bipolar plate of a flat fuel cell and a proton exchange membrane according to claim 1, wherein the bipolar plate comprises a substrate on which the electrode region is formed. 6 . The method for improving the contact between the double-electrode plate and the proton exchange membrane of a flat fuel cell according to claim 5 , wherein the substrate is made of glass fiber reinforced polymer material. 7. A kind of method for improving the double-electrode plate of flat-plate fuel cell according to claim 5 and proton exchange membrane part contacts, and wherein this substrate is the FR-1 of ANSI level, FR-2, FR-3, FR- 4. Made of FR-5, CEM-1 or CEM-3 glass fiber reinforced polymer materials.

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