Introduction to the production process of aluminum electrolytic capacitors

　　Aluminum foil is the main material of aluminum electrolytic capacitors. In order to increase the contact area between aluminum foil and electrolyte, the surface of aluminum foil is electrolytically etched to form pits and pits, which can increase the surface area of aluminum foil about seven or eight times. After galvanic etching, the aluminum foil is chemically oxidized to a dense aluminum trioxide (the dielectric of aluminum electrolytic capacitors).

　　Cutting aluminum foil

　　Depending on the size and capacity of the aluminum electrolytic capacitor, the aluminum foil is cut to the size required for the next step in the manufacturing process.

　　Riveting leads/guide pins

　　The aluminum electrolytic capacitors are not connected to the inside of the capacitor, but to the aluminum foil inside the capacitor through the lead/guide pin, which is usually made of copper inside and tin outside in order to reduce the resistance.

　　Winding electrolytic paper

　　Electrolytic paper is inserted between the cathode foil and the anode foil and then wound into a cylindrical shape. Electrolytic paper mainly serves to equalize the distribution of electrolyte and to keep the cathode foil and anode foil apart and to prevent short circuits caused by contact between the positive and negative foils of the capacitor. The electrolytic paper has a different formulation from ordinary paper, and its surface is microporous. The surface of the electrolytic paper should not have impurities, otherwise it will affect the composition and performance of the electrolyte.

　　Impregnation

　　Immersion is the process of dipping the coiled foil into the electrolyte. The electrolyte is an ion-conducting liquid, which is the real cathode (the cathode foil/negative foil of aluminum electrolytic capacitor is actually used only for leading out the cathode, so the real cathode/negative electrode is the electrolyte). The electrolyte has a very important influence on the capacitor characteristics, temperature characteristics, frequency characteristics, and service life, etc.

　　Forming and Sealing

　　The aluminum electrolytic capacitor is assembled with the outside aluminum case and the element, plugged with black rubber tip/gel, and then sealed with a girdle to block the volatility and leakage of the aluminum electrolyte.

　　Casing

　　After cleaning the dirt and oil on the surface of the bare product, the aluminum electrolytic capacitor case is covered with a plastic sleeve printed with the logo of the capacitor manufacturer, rated working voltage, capacity, working temperature, positive and negative pole identification, product series and production period, etc. This is the appearance of the finished product that you usually see.

　　Common leaded electrolytic capacitors

　　After charging, aging test, parameter check and screening out unqualified products, the finished aluminum electrolytic capacitors are processed into the lead shape required by customers and then can be packaged, warehoused and shipped.

　　Electrolytic capacitors processed and shaped as required