Alternating-current impedance analytical method of electrochemical energy storage device and analytical method of working state of electrochemical energy storage device

Abstract

The invention discloses an alternating-current impedance analytical method of an electrochemical energy storage device. The method comprises steps as follows: an integrated DC / DC converter is provided and comprises a first DC / DC converter, a disturbance source and a controller, and the first DC / DC converter is connected with the disturbance source in parallel; the controller switches on the disturbance source and controls the disturbance source to generate a current disturbance signal simultaneously; the output current of the electrochemical energy storage device is disturbed by the current disturbance signal; the disturbed output current and the output voltage of the electrochemical energy storage device are detected; the impedance corresponding to the frequency of the current disturbance signal is calculated according to the current disturbance signal as well as the disturbed output current and the output voltage, the frequency of the current disturbance signal is changed, and the output current of the electrochemical energy storage device is disturbed again to obtain the alternating-current impedance spectrum of the electrochemical energy storage device.

Description

technical field [0001] The invention relates to an AC impedance analysis method of an electrochemical energy storage device and a monitoring method for its working state. Background technique [0002] Hydrogen-oxygen proton exchange membrane fuel cell (Proton Exchange Membrane Fuel Cell, referred to as PEMFC) is an electrochemical device that directly converts chemical energy into electrical energy. The energy conversion of traditional internal combustion engines is limited by the Carnot cycle, while hydrogen-oxygen proton exchange membrane fuel cells Energy conversion is not limited by the Carnot cycle, and theoretically its energy conversion efficiency is higher. Because the substances involved in the reaction are hydrogen and air, the reaction product is water, and no harmful emissions are produced, so it is favored by people and gradually used in backup power stations, transportation, and mobile power supplies. [0003] The output characteristic of the proton exchange m...

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Problems solved by technology

In order to obtain the resistance and capacitance parameters in the equivalent circuit of the fuel cell, it is necessary to carry out AC impedance research. The commercialized AC impedance analysis equipment currently on the market, such as the products developed by Japan's KIKUSUI Kikusui Company and the UK's Solarton Company, have a price of 100,000 yuan. Its operating voltage range and current range cannot meet the requirements of the existing fuel cell bus system, and it is naturally difficult to achieve large-scale real vehicle applications

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