Aluminum electrolytic capacitor materials and process flow

Aluminum foil etching (enlarges surface area)

Aluminum foil is the main material of aluminum electrolytic capacitor, aluminum foil is set as the anode, after electricity in the electrolyte, the surface of aluminum foil will form oxide film (Al2O3), the function of the oxygen film for the dielectric.

The function of etching is to enlarge the surface area of the aluminum foil. Etching is an electrochemical process in which an AC or DC current is applied to a chloride solution.

To form (a dielectric layer)

Formation is the process of forming a dielectric layer (Al2O3) on the surface of the anode aluminum foil. The aluminum foil that has been formed is generally used as the anode.

In order to enlarge the surface area, the aluminum foil material was electrochemically etched in a chloride solution. Then, after applying a voltage higher than the rated voltage in the ammonium borate solution, the dielectric oxide layer (Al2O3) is formed on the surface of the aluminum foil. The dielectric layer is a very thin and dense oxide film, about.1~1.5nm/vot, and the insulation resistance is about 108 ~ 109Ω/m. The thickness of the oxide layer is proportional to the pressure resistance. In order to increase the efficiency of expanding the surface area, the etching shapes are different depending on the rated voltage.

cutting

Cut aluminum foil (cathode foil and anode foil) and electrolytic paper to the required size according to the size requirements of different products

winding

Insert electrolytic paper between cathode foil and anode foil, then wind into a cylindrical shape, cathode foil and anode foil connect terminals on the winding process.

Electrolytic paper mainly plays the role of balancing the distribution of electrolyte and keeping the spacing of cathode foil and anode foil.

immersion

Immersion is the process of immersing particles in an electrolyte. The electrolyte can further repair the dielectric layer.

The electrolyte, a liquid that conducts electricity by ions, is the true cathode and acts as a connection between the dielectric layer on the surface of the anode aluminum foil. The foil acts like a collector to connect the real cathode to the internal circuit. Electrolyte is the key material that determines the characteristics of capacitor (temperature characteristics, frequency characteristics, service life, etc.).

seal

Sealing is the process of putting the seeds into the aluminum shell and sealing them with sealing materials (rubber, rubber cover, etc.). The main function of the aluminum shell and the sealing material made of rubber is to keep the capacitor air tight.

aging

Aging is the process of applying a voltage to a sealed capacitor at a high temperature. This process can repair some damage to the dielectric layer during cutting and winding.

Full inspection, packing

After aging, all products will be inspected for electrical characteristics. And the terminal processing. Finally, pack.