Hydrogen as a future fuel is rapidly becoming popular, and hydrogen energy as a green energy source has been applied to power generation and fuel cell electric vehicles(FCEV)The green hydrogen production method is to use electricity and water to produce hydrogen through electrolysis. Electrolysis is the process of oxidation-reduction reactions occurring on the cathode and anode when current is passed through an electrolyte solution or molten electrolyte. At present, there are several experimental methods for electrolyzing water, including:

In recent years, with the deepening of research on the process of hydrogen production through electrolysis of water by researchers, especially in the electrolysis of solid oxides with high current density(SOEC)In technical research, there is an increasing demand for AC impedance testing.

When conducting AC impedance testing, people may usually think of using the method of scheme one (on the left side of the figure below), which is to directly connect the electrochemical workstation and the electrolytic current source in parallel at both ends of the electrolytic cell. The test results of this testing method will be affected by the internal impedance of the power supply (resistance, capacitance). In addition, during AC impedance testing, some AC signals will enter the electrolytic power supply, and the power supply operating in constant current mode needs to counteract the fluctuations of the AC signal to maintain a constant current state, which will cause corresponding fluctuations in the output of the power supply. Therefore, the AC impedance obtained in scheme one is not the true AC impedance of the electrolysis process, and there will be noise interference signals.

In response to the situation of Scheme 1,ZahnerThe company has provided a testing method for Plan 2 (on the right side of the figure below), which uses a combination of AC electronic loads. Due toZahner EL1002The special design of the AC electronic load prevents AC signals from entering the DC electrolytic power supply, so that DC current and AC current are two independent circuits that do not affect each other even under relatively high current conditions. Therefore, Scheme 2 can accurately test the AC impedance during the electrolysis process.