CN108134109B - A bipolar plate structure of a fuel cell - Google Patents

Abstract

The invention relates to a bipolar plate structure of a fuel cell, which includes a first reaction gas inlet and outlet main pipe (1), a second reaction gas inlet and outlet main pipe (2), a cooling liquid inlet and outlet main pipe (3) provided at both ends of the bipolar plate, and Connect the flow field of each inlet and outlet main pipe. The flow field includes an active zone flow channel (4), an active zone flow channel overlap zone (5) and an inactive zone flow channel overlap zone (6). The active zone flow channel (4 ) is higher than the height of the active area flow channel overlap area (5) or the inactive area flow channel overlap area (6). Compared with the existing technology, the fuel cell bipolar plate designed in the present invention enables the fuel cell to have better performance output and stability, which is beneficial to improving the power density and life of the fuel cell.

Description

A bipolar plate structure of a fuel cell

Technical field

The present invention relates to fuel cells, and in particular to a flow channel structure of a fuel cell bipolar plate.

Background technique

Fuel cells are known as the fourth generation power generation device after hydraulic, thermal and nuclear energy due to their many advantages such as high efficiency, low pollution, high reliability and easy maintenance. The proton exchange membrane fuel cell (PEMFC) is currently a relatively mature technology that can combine hydrogen with oxygen in the air to synthesize clean water and release electrical energy. Because it uses hydrogen, a renewable energy resource, and the generated reactant is water, it achieves zero emissions.

The single cell of a fuel cell is mainly composed of three major components: a membrane electrode assembly (MEA), a bipolar plate, and a sealing material. The bipolar plate has multiple functions, including: separating the reaction gas and passing the flow through it. The field introduces reaction gases into the fuel cell, collects and conducts current, supports the membrane electrodes, and undertakes the heat dissipation and drainage functions of the entire fuel cell. In order to meet the application power requirements, the actual fuel cell is composed of multiple single cells connected in series. It is stacked and pressed and packaged. The reasonable size matching of each component has become the core issue that determines the performance and reliability of the stack.

Both the authorized invention patent CN101262063 of General Motors Company (GM) and the authorized invention patent CN103119771 of Johnson Matthey Fuel Cell Company (JM) disclose an MEA structure, which considers the overlap of the active area and the inactive frame area design part. MEA performance and stability will be greatly improved. However, the overlap of this multi-layer material makes the thickness of this area 0.01mm to 0.1mm thicker than the non-overlapping active area, which leads to problems in the matching of the MEA and the bipolar plate.

The authorized invention patent CN104051772 of General Motors Company (GM) discloses a stamped bipolar plate structure. It is believed that the bipolar plate can be divided into three major areas: active area, overlap area and sealing area. The core of this patent is to The shape of the flow channel in the overlapping area is designed so that this area can form a seal between the various cavities (hydrogen, air and coolant) without affecting their respective flow characteristics.

The above-mentioned patent does not involve the matching problem of the overlapping area bipolar plate and the MEA in the thickness direction. Since the thickness of the overlapping area in the above-mentioned MEA structure is higher than that of the active area, stress is more likely to be concentrated here during the assembly process of the stack, resulting in this problem. Damage to the Gas Diffusion Layer (GDL) in the area and poor contact between the bipolar plate and the MEA in the active area, thus affecting the performance and reliability of the stack.

Contents of the invention

The purpose of the present invention is to provide a bipolar plate structure for a fuel cell with high efficiency and long life in order to overcome the above-mentioned shortcomings of the prior art.

The object of the present invention can be achieved through the following technical solutions: a bipolar plate structure of a fuel cell, including a first reaction gas inlet and outlet main pipe arranged at both ends of the bipolar plate, a second reaction gas inlet and outlet main pipe, a cooling liquid inlet and outlet main pipe, and The flow field connecting each inlet and outlet main pipe includes an active zone flow channel, an active zone flow channel overlap area and an inactive zone flow channel overlap area. It is characterized in that the height of the active zone flow channel is higher than that of the active zone flow channel. The height of the channel overlap area or inactive area flow channel overlap area.

The height of the active area flow channel is 0.01 mm to 1 mm higher than the height of the active area flow channel overlapping area or the inactive area flow channel overlapping area.

The overlapping area of the active area flow channel means that the corresponding MEA in this area is the active area for reaction.

The overlapping area of the active area flow channel is located at the inlet and outlet of the fluid at both ends of the active area flow channel. The MEA corresponding to this area is the overlap between the GDL (gas diffusion layer) and the frame.

The overlapping area of the inactive area flow channel means that the corresponding MEA in this area is an inactive area for reaction.

The overlapping area of the inactive area flow channel is located at the outermost flow channel on both sides of the active area flow channel, and the MEA corresponding to this area is the overlap between the GDL (gas diffusion layer) and the frame.

A sealing groove is provided around the flow field and each inlet and outlet main pipe, and a sealing material is placed in the sealing groove. Its function is to form a seal between the reactants and between the reactants and the cooling liquid when the sealing material is compressed.

The first reaction gas inlet and outlet main pipe and the second reaction gas inlet and outlet main pipe refer to the common channels through which different reaction gases of the fuel cell enter and exit the fuel cell from the outside.

The reaction gas includes hydrogen and air.

The cooling liquid inlet and outlet main pipe refers to a common channel for cooling fluid to enter and exit the fuel cell.

MEA is composed of a proton exchange membrane and a gas diffusion layer GDL and a catalyst layer set on both sides of it. There is a frame around the MEA, which clamps and fixes the periphery of the MEA to form an MEA component. The MEA component is assembled with a bipolar plate to form a single cell. , multiple single cells are stacked to form a fuel cell stack. Since the frame must generate overlapping areas around the MEA when clamping the MEA, the present invention weakens the height of the flow channel on the bipolar plate corresponding to these overlapping areas, so as to ensure that the height of each area is consistent when the MEA assembly is assembled with the bipolar plate. .

Compared with the prior art, the advantages of the present invention are:

1. During the assembly process of the stack, the compression force on the MEA in this area is reduced, ensuring that the MEA only withstands normal compression in the stack without causing damage caused by stress concentration.

2. The degree of MEA encroachment on the flow channel in this area is reduced, thereby ensuring that the gas flow in the bipolar plate will not be affected. Therefore, using the fuel cell bipolar plate designed in the present invention enables the fuel cell to have better performance output and stability, which is beneficial to improving the power density and life of the fuel cell.

Description of the drawings

Figure 1 is a schematic structural diagram of the bipolar plate of the present invention;

Figure 2 is a schematic diagram of the usual MEA structure;

Figure 3 is a B-B cross-sectional view of Figure 2;

Figure 4 is a plan structural view of the bipolar plate of the present invention;

Figure 5 is a cross-sectional view along line A-A of Figure 4;

FIG. 6 is an enlarged view of part A in FIG. 5 .

Detailed ways

In order to make the objectives, solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, and Not all are examples. Based on the embodiments of the present invention, those skilled in the art can understand its intention and obtain other embodiments, which all fall within the protection scope of the present invention.

Example 1

As shown in Figures 1 and 4, a bipolar plate structure of a fuel cell includes a first reactant gas inlet and outlet manifold 1, a second reactant gas inlet and outlet manifold 2, a cooling liquid inlet and outlet manifold 3 provided at both ends of the bipolar plate, and connections The flow field of each inlet and outlet of the main pipe, the flow field includes the active zone flow channel 4, the active zone flow channel overlap area 5 and the inactive zone flow channel overlap area 6, the first reaction gas enters and exits the main pipe 1, and the second reaction gas enters and exits The main pipe 2 refers to the common channel through which different reaction gases (hydrogen and air) of the fuel cell enter and exit the fuel cell from the outside. The cooling liquid inlet and outlet main pipe 3 refers to a common channel for cooling fluid to enter and exit the fuel cell.

The described active zone flow channel overlapping area 5 means that the corresponding MEA in this area is the active area of the reaction, specifically located at the fluid inlet and outlet at both ends of the active area flow channel 4. The corresponding MEA in this area is the overlap of GDL10 and frame 8. At 9.

The inactive zone flow channel overlapping area 6 refers to the inactive zone where the corresponding MEA in this area is the reaction, specifically located at the outermost flow channels on both sides of the active area flow channel 4. This area corresponds to the area corresponding to The MEA is the overlap of GDL10 with bezel 89.

As shown in Figure 2-3, MEA is composed of a proton exchange membrane and a gas diffusion layer GDL10 and a catalyst layer set on both sides of it. There is a frame 8 around the MEA, which clamps and fixes the periphery of the MEA to form an MEA component. MEA component It is assembled with a bipolar plate to form a single cell, and multiple single cells are stacked to form a fuel cell stack. Since the frame is clamped around the GDL 10 when clamping the MEA, there must be an overlapping area around the GDL 10. The present invention weakens the height of the flow channel on the bipolar plate corresponding to these overlapping areas 9, so that when the MEA assembly is assembled with the bipolar plate When doing this, ensure that the height of each area is consistent.

As shown in Figure 4-6, a sealing groove 7 is provided around the flow field and each inlet and outlet main pipe, and a sealing material is placed in the sealing groove.

Among them, the height of the active area flow channel 4 is higher than the height of the active area flow channel overlap area 5 or the height of the inactive area flow channel overlap area 6, with a height of 0.01 mm ~ 1 mm, which is consistent with the overlap height of the MEA and the frame in the MEA assembly, ensuring double When the plate is assembled with the MEA, the height of each area is consistent.

During the stack assembly process, the compression force on the MEA in this area is reduced, ensuring that the MEA can only withstand normal compression in the stack without damage caused by stress concentration. The degree of MEA encroachment on the flow channel in this area is reduced, thus ensuring that the double The gas flow in the plates is not affected.

Claims (3)

1. A bipolar plate structure of a fuel cell, comprising a first reaction gas inlet and outlet header pipe (1), a second reaction gas inlet and outlet header pipe (2), a cooling liquid inlet and outlet header pipe (3) and a flow field connected with each inlet and outlet header pipe, wherein the flow field comprises an active area flow channel (4), an active area flow channel overlapping area (5) and a non-active area flow channel overlapping area (6), and the bipolar plate structure is characterized in that the height of the active area flow channel (4) is higher than that of the active area flow channel overlapping area (5) or the non-active area flow channel overlapping area (6);

the height of the active region runner (4) is 0.01 mm-1 mm higher than that of the active region runner overlapping region (5) or the inactive region runner overlapping region (6);

the active region runner overlapping region (5) refers to an active region of the corresponding MEA in the region which is reacted;

the active region runner overlapping region (5) is positioned at the fluid inlet and outlet positions at two ends of the active region runner (4), and the MEA corresponding to the region is the overlapping position (9) of the GDL and the frame;

the inactive region runner overlapping region (6) refers to an inactive region in which the corresponding MEA is reacted;

the non-active region runner overlapping region (6) is positioned at the outermost runners at two sides of the active region runner (4), and the MEA corresponding to the region is the overlapping position (9) of the GDL and the frame;

the first reaction gas inlet and outlet header pipe (1) and the second reaction gas inlet and outlet header pipe (2) refer to common channels for different reaction gases of the fuel cell to enter and exit the fuel cell from the outside;

the cooling fluid inlet and outlet header pipe (3) refers to a common channel for cooling fluid to enter and exit the fuel cell.

2. A bipolar plate structure for a fuel cell according to claim 1, wherein the flow field and the inlet and outlet manifolds are provided with sealing grooves (7) around the periphery thereof, in which sealing material is placed.

3. The bipolar plate structure of claim 1 wherein said reactant gases comprise hydrogen and air.