CN103618092A - A fuel cell bipolar plate with enhanced reaction gas distribution - Google Patents

Abstract

A fuel cell bipolar plate for enhancing reaction gas distribution is characterized in that an anode plate and a cathode plate are respectively composed of two layers, the lower layer is a metal thin plate, the upper layer is a flow field, the flow field is a porous flow field, the porous flow field is arranged on the metal thin plate, the porous flow field is formed by molding a net material, and the aperture of the convex part of the porous flow field is between 10 mu m and 1 mm. The reactor has the advantages that the concentration of reaction gas of the membrane electrode corresponding to the flow field bulge under the condition of the galvanic pile assembly can be obviously improved, the effective area of the electrode in the running process of the galvanic pile is improved, and the output power and the specific power density of the galvanic pile are greatly improved; defects, stress and the like caused by a corrugated flow field and the like at the stamping part of the metal plate can be avoided, and the bipolar plate has high flatness; the thickness of the bipolar plate can be controlled to be very low, so that the thickness of the galvanic pile is reduced, and the volume specific power is improved; the material is simple, the process is mature, and a new material or a new process does not need to be developed; the structure is simple, the conventional structure is simply improved, and the large influence on the assembly and the structure of the electric pile is avoided.

Description

A fuel cell bipolar plate with enhanced reaction gas distribution

technical field

The invention belongs to the technical field of fuel cells, in particular to a bipolar plate for high current density operating fuel cells.

Background technique

Proton exchange membrane fuel cell bipolar plates are mainly divided into three categories: 1. Bipolar plates that mechanically engrave a flow field on a hard graphite plate; 2. Bipolar plates that punch out a flow field from a thin metal plate; 3. Carbon powder , resin, etc. are mixed and then molded to form a bipolar plate. In addition, there are expanded graphite impregnated with resin and then stamped into bipolar plates.

The disadvantage of the bipolar plate in the prior art is: the reaction gas concentration on the membrane electrode corresponding to the bipolar plate flow field protrusion is very small, and this part of the battery area contributes little to the overall performance, which affects the effective improvement of battery performance . The reason for this shortcoming is that the protruding steps of the flow field of the bipolar plate are airtight, and the reactant gas flows in the flow field groove and is transferred to the corresponding membrane electrode surface, and passes through the membrane electrode at the flow field bulge. Deformation occurs under the action of the fastening force of the stack, resulting in a very low concentration of reactant gas, or even blocked by liquid water, without reactant gas.

Contents of the invention

The object of the present invention is to provide a fuel cell bipolar plate with enhanced reaction gas distribution, which overcomes the disadvantages of the existing bipolar plate.

The technical solution of the present invention is: a fuel cell bipolar plate that strengthens the distribution of reaction gases, including an anode plate and a cathode plate with a flow field, which is characterized in that: the anode plate and the cathode plate are two-layer structures, and It is a thin metal plate, the upper layer is a flow field, the thin metal plate is a flat plate, the flow field is a porous flow field, and the porous flow field is placed on the thin metal plate.

A fuel cell bipolar plate for enhancing reaction gas distribution according to the present invention is characterized in that: the porous flow field plate is a flow field plate made by molding a mesh material, and the pore diameter of the protrusion of the porous flow field plate is between 10 μm and between 1mm.

A fuel cell bipolar plate for enhancing reaction gas distribution according to the present invention is characterized in that: the mesh material includes metal mesh material and non-metal mesh material, and the metal mesh material is nickel foam, stainless steel mesh, titanium mesh or titanium alloy Net, the non-metallic net material is a net with gold, silver or carbon conductive material on the non-metallic net.

A fuel cell bipolar plate for enhancing reaction gas distribution according to the present invention is characterized in that: the flow channel width of the porous flow field plate is 0.2-2.0 mm, the flow channel depth is 0.1-2.0 mm, and the width of the protrusion is 0.2-2.0 mm. 0.1-1.5mm, the height of the protrusion is 0.1-2.0mm, and the total thickness of the flow field is 0.2-3.0mm.

The fuel cell bipolar plate for enhancing reaction gas distribution according to the present invention is characterized in that the thickness of the thin metal plate is 0.05-1.5 mm.

The beneficial effects of the present invention are;

1. It can significantly increase the reaction gas concentration of the membrane electrode corresponding to the flow field protrusion under the stack assembly condition, increase the effective area of the electrode during the operation of the stack, and greatly increase the output power and specific power density of the stack ;

2. It can avoid defects and stress caused by the corrugated flow field at the stamping part of the metal plate, and the flatness of the bipolar plate is high, and the reliability of the stack structure is good;

3. The thickness of the bipolar plate can be controlled at a very low level, thereby reducing the thickness of the stack and increasing the volume specific power;

4. The material is simple and the process is mature, so there is no need to develop high-tech materials or new processes;

5. The structure is simple, only a simple improvement on the conventional structure of the existing fuel cell is enough, and it does not have a great impact on the assembly and structure of the stack

Description of drawings

Figure 1 is a schematic diagram of a conventional metal bipolar plate and the concentration distribution of reaction gases.

Fig. 2 is a schematic diagram of highly integrated metal bipolar plate and reaction gas concentration distribution.

Among the figure, 1. conventional bipolar plate; 2. the reaction gas concentration of conventional bipolar plate corresponding membrane electrode surface; 3. thin metal plate; 4. porous flow field plate; Reactive gas concentration

Detailed ways

The present invention will be further described below in conjunction with drawings and embodiments.

The fuel cell bipolar plate that strengthens the distribution of reaction gas, the anode plate and the cathode plate are composed of two layers, the lower layer is a thin metal plate 3, the upper layer is a flow field plate, the flow field is a porous flow field plate 4, and the porous flow field plate 4 is placed On the thin metal plate 3, the porous flow field plate 4 is molded from a mesh material, and the hole diameter of the protrusion of the porous flow field plate 4 is between 10 μm and 1 mm. The porous flow field plate 4 is molded from a titanium alloy mesh, and the specific preparation method is as follows:

1) The titanium alloy mesh with a thickness of 2.0mm and a pore diameter of 600μm is stamped into a reactive air flow field plate through a grinding tool under a pressure of 1.0MPa. The height is 0.5mm, and the overall thickness of the flow field plate is 1.0mm;

2) Gold plating on the surface of the reaction gas field plate;

3) Gold plating on the surface of 0.08mm thick 316L stainless steel;

4) Place the gold-plated reaction gas field plate on the gold-plated stainless steel plate to form the anode plate and the cathode plate respectively. A single cell or stack can be assembled with components such as anode plate, cathode plate, electrode and end plate.

Claims (5)

1. strengthen the fuel battery double plates that reacting gas distributes for one kind, comprise the positive plate and the minus plate that are furnished with flow field, it is characterized in that: described positive plate and minus plate are by two-layer formation, lower floor is sheet metal (3), upper strata is flow-field plate, described sheet metal is dull and stereotyped, and described flow-field plate is porous flow field plate (4), and porous flow field plate (4) is placed on sheet metal (3).

2. a kind ofly according to claim 1 strengthen the fuel battery double plates that reacting gas distributes, it is characterized in that: described porous flow field plate (4) is the flow-field plate that net materials mold pressing is made, the aperture of porous flow field plate (4) high spot is between 10 μ m～1mm.

3. a kind ofly according to claim 2 strengthen the fuel battery double plates that reacting gas distributes, it is characterized in that: described net materials comprises wire netting material and nonmetal net materials, wire netting material is nickel foam, stainless (steel) wire, titanium net or titanium alloy reticulated, and nonmetal net materials is the net at nonmetal online plating gold, silver or carbonaceous conductive material.

4. a kind ofly according to claim 1 strengthen the fuel battery double plates that reacting gas distributes, it is characterized in that: the width of flow path of described porous flow field plate (4) is 0.2～2.0mm, flow channel depth is 0.1～2.0mm, high spot width is 0.1～1.5mm, high spot height is 0.1～2.0mm, and flow-field plate gross thickness is 0.2～3.0mm.

5. a kind ofly according to claim 1 strengthen the fuel battery double plates that reacting gas distributes, it is characterized in that: described sheet metal (3) thickness is 0.05～1.5mm.

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