Study Of Working Electrolyte Of Low Voltage Large Capacitance Wet Tantalum Capacitors

The main content of this project is to prepare working electrolyte for low voltage, large capacitance wet tantalum capacitors.We analyzed the ion distribution at the interface of the electrolyte and the cathode metal, and studied the factors affected the conductivity of electrolyte under the direction of Depolarizing theory, Cathode capacitance theory, and Conductance theory of the electrolyte.When the capacitor is working and with the effect of electric field, double electric layer would be formed at the interface of the electrolyte and the cathode metal. Adding some ions (depolarizer) with higher electrode voltage than hydrogen ion into electrolyte could modify the structure and reduce thickness of double electric layer, raise cathode capacitance and improve the stability of capacitance. Furthermore, depolarizer could suppress hydrogen gas generation, reduce inner pressure and improve reliability and service life of capacitor.Increasing working electrolyte conductivity can effectively decrease capacitor ESR (Equivalent Series Resistance). Besides the factors contributed to conductivity, other features of electrolyte, such as the mending ability for the dielectric film, saturation steam pressure, boiling point and viscosity were considered at the same time to improve the combined performance of capacitor.Orthogonal test was used to select elementary electrolyte batch formula, and then assembled the selected electrolyte into capacitors, measured their performance at room temperature, high and low temperature, 1000h high temperature burden examination were carried out soon afterwards. The results turned out to be good, and achieved the anticipated purpose of study.