A fuel cell stack collector plate surface local composite coating treatment structure

Abstract

The utility model relates to hydrogen fuel cell stack technical field, and disclose a kind of fuel cell stack current collecting plate surface local composite coating treatment structure, this processing structure is composed of upper end plate, upper insulating plate, upper current collecting plate, bipolar plate and membrane electrode assembly, lower current collecting plate, lower insulating plate, lower end plate, wherein bipolar plate and membrane electrode assembly are arranged between upper current collecting plate and lower current collecting plate, the upper insulating plate is located between upper end plate and upper current collecting plate, the lower insulating plate is installed between lower current collecting plate and lower end plate.The fuel cell stack current collecting plate surface local composite coating treatment structure disclosed in the utility model, Teflon spraying process has confirmed that it can reduce 90% metal ion pollution, local coating technology is applied to fuel cell end plate insulation treatment, withstand voltage strength reaches 3kV / mm, gradient coating structure has production verification, and contact resistance is reduced to 0.5mΩ level.

Description

Technical Field

[0001] This utility model relates to the field of fuel cell stack technology, specifically to a structure for partial composite coating treatment on the surface of a fuel cell stack current collector. Background Technology

[0002] A hydrogen fuel cell stack is a device that converts chemical energy into electrical and thermal energy through an electrochemical reaction of hydrogen and oxygen. The performance of the hydrogen fuel cell stack directly affects the energy conversion efficiency of the hydrogen fuel cell engine system. A hydrogen fuel cell system includes an air system, a hydrogen system, a cooling system, the stack, current collectors, and gas distribution components. The current collectors, as crucial components for the positive and negative electrode outputs of the stack, are primarily responsible for collecting and discharging the current from the positive and negative electrodes.

[0003] Currently, the durability of the current collector installed between the insulation plate and the bipolar plate is a problem that cannot be ignored, especially the oxidation reaction that may occur in high-temperature environments and the easy corrosion in acidic reaction environments. Therefore, it is necessary to use surface modified coatings for protection. Thus, there is an urgent need for a local composite coating treatment structure on the surface of the current collector of fuel cell stack to solve the above-mentioned technical problems. Utility Model Content

[0004] The purpose of this invention is to provide a local composite coating treatment structure on the surface of the current collector plate of a fuel cell stack, so as to solve the problems mentioned in the background art.

[0005] To achieve the above objectives, this utility model provides the following technical solution: A partial composite coating treatment structure for the surface of a fuel cell stack current collector plate is disclosed. This structure comprises an upper end plate, an upper insulating plate, an upper current collector plate, a bipolar plate and a membrane electrode assembly, a lower current collector plate, a lower insulating plate, and a lower end plate. The bipolar plate and the membrane electrode assembly are disposed between the upper and lower current collector plates. The upper insulating plate is located between the upper end plate and the upper current collector plate. The lower insulating plate is installed between the lower current collector plate and the lower end plate. The top of the upper and lower current collector plates forms the current collector plate inlet / outlet area, and below this area is the flow channel area. The middle portion of the upper and lower current collector plates is the conductive contact area. The upper two sides of the composite coating treatment structure are current conduction areas.

[0006] The bipolar plate in the bipolar plate and membrane electrode assembly consists of two anode plates and cathode plates of the same shape and size.

[0007] The anode plate is mainly responsible for contacting fuel hydrogen or methanol and generating charged particles protons and electrons through catalytic decomposition. The protons then pass through the anode plate and combine with the oxidant on the cathode plate to generate current and water. The cathode plate is used to catalyze the reaction with the oxidant, also generating current and water.

[0008] In particular, Teflon spraying is used in the air inlet and outlet areas and the flow channel area of ​​the manifold to form an insulating and anti-corrosion layer of 30-100μm. This insulating and anti-corrosion layer is a composite coating structure, and the conductive contact area and the current conduction area are treated with gold plating, silver plating or nickel plating.

[0009] The insulating and anti-corrosion layer is a gradient structure composed of a metal plating layer and a Teflon coating. The metal plating layer is the bottom layer, which is a 10μm silver plating layer with a contact resistance ≤0.5mΩ·cm². The Teflon coating layer is the top layer, which is a 100μm nano-modified Teflon and contains 10% silicon carbide particles to enhance adhesion.

[0010] Compared with the prior art, the present invention has the following advantages: The present invention has a local composite coating treatment structure on the surface of the current collector of the fuel cell stack. The Teflon spraying process has been proven to reduce metal ion pollution by 90%. The local coating technology is applied to the insulation treatment of the fuel cell end plate, with a withstand voltage strength of 3kV / mm. The gradient coating structure has been verified in mass production, and the contact resistance is reduced to the 0.5mΩ level. Attached Figure Description

[0011] Other features, objects, and advantages of this application will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a front view of the partial composite coating treatment structure on the surface of the current collector plate of the fuel cell stack of this utility model; Figure 2 This is a reverse view of the partial composite coating treatment structure on the surface of the current collector plate of the fuel cell stack of this utility model; Figure 3 This is a schematic diagram of the overall structure of the fuel cell stack of this utility model; In the diagram: 1-Upper end plate, 2-Upper insulating plate, 3-Upper current collector, 4-Bipolar plate and membrane electrode assembly, 5-Lower current collector, 6-Lower insulating plate, 7-Lower end plate, 8-Inlet and outlet area of ​​current collector, 9-Flow channel area, 10-Conductive contact area, 11-Current discharge area. Detailed Implementation

[0012] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the utility model. Furthermore, it should be noted that, for ease of description, only the parts relevant to the utility model are shown in the accompanying drawings. In the embodiments of the present utility model, the different types of cross-sectional lines are not labeled according to national standards, nor do they specify material requirements for the components; they are used to distinguish the cross-sectional views of the components in the drawings.

[0013] Please see Figure 1-3A partial composite coating treatment structure for the surface of a fuel cell stack current collector plate is disclosed. This structure comprises an upper end plate 1, an upper insulating plate 2, an upper current collector plate 3, a bipolar plate and a membrane electrode assembly 4, a lower current collector plate 5, a lower insulating plate 6, and a lower end plate 7. The bipolar plate and the membrane electrode assembly 4 are disposed between the upper current collector plate 3 and the lower current collector plate 5. The upper insulating plate 2 is located between the upper end plate 1 and the upper current collector plate 3. The lower insulating plate 6 is installed between the lower current collector plate 5 and the lower end plate 7. The top of the upper current collector plate 3 and the lower current collector plate 5 forms a current inlet / outlet region 8, and below the current inlet / outlet region 8 is a flow channel region 9. The middle part of the upper current collector plate 3 and the lower current collector plate 5 is a conductive contact region 10. The upper two sides of the composite coating treatment structure are current outflow regions 11.

[0014] Among them, the bipolar plate and membrane electrode assembly 4 consists of two anode plates and cathode plates of the same shape and size.

[0015] The anode plate is mainly responsible for contacting the fuel hydrogen or methanol and generating charged particles protons and electrons through catalytic decomposition. The protons then pass through the anode plate and combine with the oxidant on the cathode plate to generate current and water. The cathode plate is used to catalyze the reaction with the oxidant, also generating current and water.

[0016] In particular, the air inlet and outlet areas 8 and flow channel areas 9 of the manifold are both coated with Teflon to form an insulating and anti-corrosion layer of 30-100μm. This insulating and anti-corrosion layer is a composite coating structure. The conductive contact area 10 and the current output area 11 are treated with gold plating, silver plating or nickel plating.

[0017] The insulating and anti-corrosion layer is a gradient structure composed of a metal plating layer and a Teflon coating. The metal plating layer is the bottom layer, which is a 10μm silver plating layer with a contact resistance ≤0.5mΩ·cm². The Teflon coating layer is the top layer, which is a 100μm nano-modified Teflon and contains 10% silicon carbide particles to enhance adhesion.

[0018] It should be noted that the local composite coating treatment structure on the surface of the fuel cell stack current collector plate uses Teflon spraying process in the gas inlet / outlet area 8 and flow channel area 9 of the current collector plate to form an insulating and anti-corrosion layer of 30-100μm. Other conductive contact areas 10 (such as the core contact part) are treated with gold / silver or nickel plating. The coating boundary control with a precision of 0.1mm is achieved by photolithography mask or laser positioning technology to avoid mutual interference between the conductive area and the anti-corrosion area.

[0019] The table below compares the structure of the fuel cell stack current collector with the traditional structure, showing a partial composite coating treatment:

[0020] The fuel cell stack current collector surface local composite coating treatment structure is the first of its kind with a gradient structure of "metal coating (bottom layer) + Teflon coating (top layer)": The bottom layer consists of a 10μm silver plating layer (contact resistance ≤0.5mΩ·cm²). Surface layer: 100μm nano-modified Teflon (containing 10% silicon carbide particles to enhance adhesion) Meanwhile, plasma activation technology (argon environment, power 500W) is introduced in the pretreatment stage to improve the coating bonding strength by 40%, and pulse spraying process (frequency 20kHz, temperature 380℃) is adopted to achieve a coating porosity of <0.5%.

[0021] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

[0022] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of the utility model involved in this application is not limited to the technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the inventive concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. A structure for partial composite coating treatment on the surface of a fuel cell stack current collector plate, characterized in that: The processing structure consists of an upper end plate (1), an upper insulating plate (2), an upper current collector (3), a bipolar plate and a membrane electrode assembly (4), a lower current collector (5), a lower insulating plate (6), and a lower end plate (7). The bipolar plate and the membrane electrode assembly (4) are disposed between the upper current collector (3) and the lower current collector (5). The upper insulating plate (2) is located between the upper end plate (1) and the upper current collector (3). The lower insulating plate (6) is installed between the lower current collector (5) and the lower end plate (7). The top of the upper current collector (3) and the lower current collector (5) is the current collector inlet / outlet area (8). Below the current collector inlet / outlet area (8) is the flow channel area (9). The middle part of the upper current collector (3) and the lower current collector (5) is the conductive contact area (10). The upper two sides of the composite coating processing structure are current outflow areas (11).

2. The structure for partial composite coating treatment on the surface of a fuel cell stack current collector plate according to claim 1, characterized in that: The bipolar plate in the bipolar plate and membrane electrode assembly (4) consists of two anode plates and cathode plates of the same shape and size.

3. The structure for partial composite coating treatment on the surface of a fuel cell stack current collector plate according to claim 1, characterized in that: In the inlet and outlet areas (8) and flow channel areas (9) of the manifold, Teflon spraying process is used to form an insulating and anti-corrosion layer of 30-100μm. The insulating and anti-corrosion layer is a composite coating structure. The conductive contact area (10) and the current output area (11) are treated with gold plating, silver plating or nickel plating.

4. The structure for partial composite coating treatment on the surface of a fuel cell stack current collector plate according to claim 3, characterized in that: The insulating and anti-corrosion layer is a gradient structure composed of a metal plating layer and a Teflon coating. The metal plating layer is the bottom layer, which is a 10μm silver plating layer with a contact resistance ≤0.5mΩ·cm². The Teflon coating layer is the top layer.

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