阅读说明：本技术 一种质子交换膜燃料电池膜电极的快速活化方法及其应用 (Rapid activation method and application of membrane electrode of proton exchange membrane fuel cell ) 是由 王峰 李宁 窦美玲 王琨 于 2019-11-04 设计创作，主要内容包括：本发明涉及一种质子交换膜燃料电池膜电极的快速活化方法及其应用,其目的是为了能够使膜电极在更短的时间内达到最佳状态,所述的快速活化方法是电压以恒定速率线性降低的连续高频变电压强制活化。与现有恒电流活化方式相比,本发明提出的活化方式简单易行,可明显缩短活化时间,对提高燃料电池活化效率及节能减排具有重要意义。(The invention relates to a rapid activation method of a membrane electrode of a proton exchange membrane fuel cell and application thereof, aiming at enabling the membrane electrode to reach an optimal state in a shorter time. Compared with the existing constant current activation mode, the activation mode provided by the invention is simple and easy to implement, can obviously shorten the activation time, and has important significance for improving the activation efficiency of the fuel cell and saving energy and reducing emission.)

1. A fast activation method for membrane electrode of proton exchange membrane fuel cell features that the continuous high-frequency voltage variation with linear decrease of voltage at constant speed is used to activate the membrane electrode.

2. The rapid activation method according to claim 1, comprising the specific steps of:

the method comprises the following steps: after leakage testing and purging are carried out on the fuel cell, respectively introducing an oxidant and hydrogen into a cathode and an anode, and then carrying out continuous high-frequency variable pressure braking and activation on the fuel cell, wherein the continuous high-frequency variable pressure braking and activation is to linearly reduce the voltage from the open-circuit voltage to a preset low voltage value at a constant rate, and when the voltage of the cell is reduced to the low voltage value, the current is quickly cut off, and the cell is recovered to the open-circuit voltage;

step two: and repeating the first activation step, recording the polarization curve and the power density curve of the activation process in real time in each activation process, and finishing the activation if the polarization curve and the power density curve are basically superposed after the activation for three times continuously.

3. The rapid activation method according to claim 2, wherein in the first step, the hydrogen gas is pure hydrogen gas with a stoichiometric ratio of 1.0-1.5, the oxidant is pure oxygen gas or air with a stoichiometric ratio of 1.0-2.5, the working pressure is 0-0.2Mpa, and the relative humidity is 50-100%.

4. The rapid activation method according to claim 2, wherein the temperature condition for forced activation in the first step is 50-80 ℃.

5. The rapid activation method according to claim 2, wherein in the first step, the constant voltage variation rate is in the range of 1-50 mV s ^-1。

6. The rapid activation method according to claim 2, wherein in the first step, the low voltage is in the range of 0.15-0.4V.

7. The rapid activation method according to any one of claims 1 to 6 is the use in single cell activation or stack activation.

Technical Field

The invention relates to the technical field of fuel cells, in particular to a rapid activation method of a membrane electrode of a proton exchange membrane fuel cell and application thereof.

Background

A Proton Exchange Membrane Fuel Cell (PEMFC) is an energy conversion device that directly converts chemical energy in fuel into electrical energy through electrochemical reaction, and is considered to be an ideal choice for future vehicle power due to its advantages of high energy conversion efficiency, cleanliness, and the like. PEMFC cells consist of a membrane electrode assembly, bipolar plates, current collectors, and end plates, where the membrane electrode assembly (consisting of a proton exchange membrane, a catalytic layer, and a gas diffusion layer) is the key to the fuel cell. After the initial assembly of the fuel cell is completed, proton conduction is hindered due to water shortage inside the proton exchange membrane and the catalyst layer. Therefore, in order to rapidly construct a reasonable proton, electron and gas-liquid phase conduction network and exert the best performance of the fuel cell, the activation operation of the fuel cell is required.

Chinese patent application 201610519404.0 discloses an activation method of proton exchange membrane fuel cell stack, comprising the steps of: mounting the battery stack after primary assembly on an activation table, and detecting air tightness; introducing N into both the cathode and the anode of the cell stack ₂Purging; setting a working temperature; RH 80% humidified air is introduced into the cathode, and unhumidified H is introduced into the anode ₂The gas pressure is 60-100 Kpa in normal discharge; applying current, air and H to the stack by means of a load ₂The stoichiometric ratios of (a) and (b) are 3.5 and 1.5, respectively; mixing air with H ₂The stoichiometric ratio of (a) was set to 3.0 and 1.5, respectively, and the operation was continued for 30 min at the highest current; the electric current is quickly reduced to 0A, the circuit is disconnected, the cooling water is introduced to cool the cell stack, the cell stack is cooled to the room temperature, then the primarily-installed cell stack is secondarily fastened, the compression amount of the cell stack reaches the set technical index, and the fuel cell stack can be simply, conveniently and quickly activated to the optimal state.

The existing activation mode usually adopts the activation by long-time constant current discharge under fixed current density, and the activation mode needs longer time; in addition, long-term activation consumes a large amount of fuel, wasting resources. Therefore, in order to rapidly reach the optimum state of the membrane electrode in a shorter time, it is necessary to find a rapid activation method of the fuel cell.

Disclosure of Invention

The invention provides a rapid activation method of a membrane electrode of a proton exchange membrane fuel cell and application thereof, aiming at solving the problem of longer activation time of the existing activation mode, and aiming at enabling the membrane electrode to reach an optimal state in a shorter time. Compared with the existing constant current activation mode, the activation mode provided by the invention is simple and easy to implement, can obviously shorten the activation time, and has important significance for improving the activation efficiency of the fuel cell and saving energy and reducing emission.

In a specific embodiment of the present invention, the rapid activation method comprises the following specific steps:

the method comprises the following steps: after leakage testing and purging are carried out on the fuel cell, respectively introducing an oxidant and hydrogen into a cathode and an anode, and then carrying out continuous high-frequency variable pressure braking and activation on the fuel cell, wherein the continuous high-frequency variable pressure braking and activation is to linearly reduce the voltage from the open-circuit voltage to a preset low voltage value at a constant rate, and when the voltage of the cell is reduced to the low voltage value, the current is quickly cut off, and the cell is recovered to the open-circuit voltage;

step two: and repeating the first activation step, recording the polarization curve and the power density curve of the activation process in real time in each activation process, and finishing the activation if the polarization curve and the power density curve are basically superposed after the activation for three times continuously.

In a preferred embodiment of the present invention, in the first step, the hydrogen is pure hydrogen with a stoichiometric ratio of 1.0-1.5, the oxidant is pure oxygen or air with a stoichiometric ratio of 1.0-2.5, the working pressure is 0-0.2Mpa, and the relative humidity is 50-100%.

In a preferred embodiment of the present invention, in the first step, the temperature condition for forced activation is 50-80 ℃.

In a preferred embodiment of the present invention, in the first step, the constant voltage variation rate is in the range of 1-50 mV s ^-1。

In a preferred embodiment of the present invention, in the first step, the low voltage is in the range of 0.15-0.4V.

The invention provides a rapid activation method for protecting a membrane electrode of a proton exchange membrane fuel cell, which is applied to single cell activation or electric pile activation.

Compared with the prior art, the invention has the advantages that: electrode reaction is promoted to be thoroughly carried out by constant-speed continuous high-frequency transformer pressure control activation, a reasonable proton, electron and gas-liquid phase conduction network can be quickly constructed, the time required by the activation mode is only 60-70 min, the time required by the activation mode is shorter than that required by the existing activation mode, the activation efficiency of the fuel cell can be improved, and energy conservation and emission reduction are facilitated.

Drawings

The following is further described with reference to the accompanying drawings:

FIG. 1 is a graph of voltage versus time for the membrane electrode activation process of a fuel cell in example 1;

FIG. 2 is a plot of polarization versus power density for the fuel cell of example 1 before and after activation;

FIG. 3 is a graph showing the change of current with time during the activation of a membrane electrode of a fuel cell in a comparative example;

fig. 4 is a polarization curve and a power density curve before and after activation of the fuel cell in the comparative example.

Detailed Description

The principles and features of this invention are described below in conjunction with the following drawings, which are set forth by way of illustration only and are not intended to limit the scope of the invention.