Fuel-cell bipolar plate with nitrified and enhanced surface and preparation method thereof

A fuel cell, nitriding enhanced technology, applied in the direction of battery electrodes, circuits, electrical components, etc., can solve the problems of affecting the catalyst activity in the battery, the contact resistance becomes larger, and the coating bonding force is small, so as to improve the coating bonding force , reduce the potential difference, reduce the effect of coating internal stress

Active Publication Date: 2015-04-29
CHANGZHOU INST OF DALIAN UNIV OF TECH
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  • Application Information

AI Technical Summary

Problems solved by technology

[0008] If the thickness of the film is too thin, the oxygen distributed in the cathode can diffuse through the pores and directly reach the bipolar plate substrate, making it passivated, resulting in an increase in the overall contact resistance, which directly leads to an increase in the internal resistance of the battery and a decrease in the output voltage of the battery, which affects the use, and The greater the contact resistance of the bipolar plate, the more ohmic heat will be generated during the battery operation, and the temperature rise of the battery will also affect the activity of the catalyst in the battery; in addition, the pore defects of the vacuum coating will cause the substrate to be exposed In the external environment, galvanic corrosion occurs where it acts as an anode, leading to premature failure of the coating
[0009] In addition, the existing technology is to directly coat the carbon-chromium film on the metal substrate. This treatment method will cause the coating bonding force between the carbon-chromium film and the substrate to be weak, resulting in the phenomenon of film peeling during use.
[0010] Therefore, the main problem currently facing is how to enhance the corrosion resistance of the fuel cell bipolar plate surface film on the premise of ensuring a thinner film thickness when preparing the carbon chromium film of the fuel cell bipolar plate.

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  • Fuel-cell bipolar plate with nitrified and enhanced surface and preparation method thereof

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Embodiment 1

[0037] The method for nitriding enhanced surface modification of bipolar plates for fuel cells is characterized in that the method comprises the following process steps:

[0038] This embodiment is implemented according to the following steps under the following implementation conditions and technical requirements:

[0039] (1) Nitriding layer preparation

[0040] Put the stainless steel plate or titanium alloy plate substrate 1 into the ultrasonic cleaning equipment for cleaning, and after drying in the vacuum drying furnace, install it into the vacuum chamber of the pulse bias arc ion plating equipment with a special fixture, and put the vacuum in the vacuum system. After vacuuming the chamber to 0.5Pa, heat the vacuum chamber to 400°C, and control the flow meter to feed 3000SCCM of nitrogen and 1500SCCM of hydrogen to maintain the pressure in the vacuum chamber at 3pa, and apply a pulse bias of -500V on the bipolar plate. The duty cycle is 90%, the working frequency is 5KH...

Embodiment 2

[0049] The method for nitriding enhanced surface modification of bipolar plates for fuel cells is characterized in that the method comprises the following process steps:

[0050] This embodiment is implemented according to the following steps under the following implementation conditions and technical requirements:

[0051] (1) Nitriding layer preparation

[0052] Put the stainless steel plate or titanium alloy plate substrate 1 into the ultrasonic cleaning equipment for cleaning, and after drying in the vacuum drying furnace, install it into the vacuum chamber of the pulse bias arc ion plating equipment with a special fixture, and put the vacuum in the vacuum system. After vacuuming the chamber to 0.3Pa, heat the vacuum chamber to 250°C, and pass 3000SCCM of nitrogen and 800SCCM of hydrogen through the control flowmeter to maintain the pressure in the vacuum chamber at 1.5Pa, and apply a pulse of -750V on the bipolar plate Bias voltage, the duty cycle is 50%, the working fre...

Embodiment 3

[0060] The method for nitriding enhanced surface modification of bipolar plates for fuel cells is characterized in that the method comprises the following process steps:

[0061] This embodiment is implemented according to the following steps under the following implementation conditions and technical requirements:

[0062] (1) Nitriding layer preparation

[0063] Put the stainless steel plate or titanium alloy plate substrate 1 into the ultrasonic cleaning equipment for cleaning, and after drying in the vacuum drying furnace, install it into the vacuum chamber of the pulse bias arc ion plating equipment with a special fixture, and put the vacuum in the vacuum system. After vacuuming the chamber to 0.001Pa, heat the vacuum chamber to 100°C, and control the flow meter to feed 20SCCM of nitrogen and 10SCCM of hydrogen to maintain the pressure in the vacuum chamber at 0.1Pa, and apply a pulse of -1000V on the bipolar plate Bias voltage, the duty cycle is 10%, the working frequen...

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Abstract

The invention discloses a fuel-cell bipolar plate with a nitrified and enhanced surface and a preparation method thereof and belongs to the technical field of fuel cells. The bipolar plate is prepared by the following steps of: preparing a nitrified layer, a chromium-nitride thin film and a carbon-based nano composite conductive thin film on the two side surfaces of a matrix of a stainless-steel plate or a titanium-alloy plate in sequence, cleaning and drying the matrix of the stainless-steel plate or the titanium-alloy plate, then putting the matrix in vacuum-arc ion-plating equipment, introducing nitrogen and hydrogen under the vacuum condition, starting bias voltage and hot wires, and preparing the nitrified layer; and introducing argon-nitrogen mixed gas, preparing the chromium-nitride thin film, opening a carbon target and preparing the carbon-based nano composite conductive thin film. The fuel-cell bipolar plate disclosed by the invention has the advantages that an ion nitrification technology is introduced into the field of surface modification of the fuel-cell bipolar plate, and the nitrified layer is prepared on the surface, so that the passivation of the matrix can be avoided, the condition that a coating fails due to corrosion can be effectively prevented; and a stepped transition method is adopted for multi-element composition of the chromium-nitride thin film and the nano composite conductive thin film, so that the peeling of the coating in the use process due to overlarge internal stress and oversmall bonding force is prevented.

Description

technical field [0001] The invention belongs to the technical field of fuel cells, in particular to a fuel cell bipolar plate with enhanced surface and a preparation method thereof. Background technique [0002] Due to its high energy conversion efficiency, high power density, safety and environmental protection, fuel cells have attracted the attention of governments and research institutions in various countries. It is considered to be a high-efficiency energy device that can alleviate the depletion of resources and environmental pollution. Among them, the proton exchange membrane fuel cell (PEMFC) has the advantages of high energy conversion efficiency (40% to 60%), zero emission, fast start-up and high specific power, and is considered to be used in vehicle power supplies, distributed power stations and portable power supplies. ideal device. With the application of proton exchange membrane batteries in vehicles such as automobiles, as a new generation of energy technolog...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/88H01M4/86H01M4/96
CPCH01M4/86H01M4/8817H01M4/8896H01M4/96Y02E60/50
Inventor 林国强韩治昀魏科科
Owner CHANGZHOU INST OF DALIAN UNIV OF TECH
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