WEE Technology Company Limited - WEE are Capacitors Specialist

Today we will go on the topic about Aluminum Electrolytic Capacitors failure mode and cause analysis

3. Break down

The breakdown of aluminum electrolytic capacitor is caused by the rupture of anodic alumina dielectric film, which leads to direct contact between electrolyte and anode. The alumina membrane may be locally damaged due to various materials, processes or environmental conditions. Under the action of external electric field, the oxygen ion supplied by working electrolyte can form oxide film again at the damaged part, which makes the anodic oxide film filled and repaired. However, if there are impurity ions or other defects in the damaged parts, so that the filling and repairing work can not be completed, then there will be micro holes on the anodic oxide film, or even become through holes, which will make the aluminum electrolytic capacitor breakdown.

In addition, with the increase of use and storage time, the solvent in the electrolyte is gradually consumed and volatilized, which makes the acid value of the solution increase, and the oxidation film is corroded during storage. At the same time, due to the aging and drying up of electrolyte, oxygen ion can not be provided to repair the oxide film under the action of electric field, thus the self-healing effect is lost. Once the oxide film is damaged, the capacitor will be broken down. The process defect is also a main reason for the breakdown of aluminum electrolytic capacitor. If the riveting process is not good, the burr on the lead-in chaff will seriously hurt the oxide film, and the leakage current of the stabbed part is very large, and the local overheating will cause thermal breakdown of the capacitor. In use, over temperature, ripple current or mechanical stress may make the capacitor breakdown failure.

4. Burn down

The burning of aluminum electrolytic capacitor is generally caused by the following reasons:

① The positive and negative poles are reversed. Aluminum electrolytic capacitor is a kind of capacitor with positive and negative electrodes. If the positive and negative electrodes are wrongly connected when installing the aluminum electrolytic capacitor, the capacitor will burn out;

② The pressure is not enough. When the voltage exceeds the withstand voltage value of aluminum electrolytic capacitor, the capacitor will burn out;

③ The quality is unqualified. The aluminum electrolytic capacitors produced by some manufacturers are not up to standard, which may lead to the burning of capacitors.