The principle of aluminum electrolytic capacitor lids
Release date:
2025-11-13
The lid of an aluminum electrolytic capacitor is a critical sealing component in its structure. Its core principle lies in protecting the internal core assembly—composed of anode aluminum foil, cathode aluminum foil, electrolyte, and separator paper wound together—through a robust sealing mechanism, while simultaneously ensuring electrical connectivity.
The lid of an aluminum electrolytic capacitor is a critical sealing component in its structure. Its core principle lies in protecting the internal core assembly—composed of anode aluminum foil, cathode aluminum foil, electrolyte, and separator paper wound together—and ensuring electrical connectivity through a robust sealing mechanism. Typically made from rubber plugs (such as EPDM or butyl rubber) or resin lids (like phenolic resin or polyphenylene sulfide), the lid works in conjunction with the aluminum casing to create a hermetically sealed environment, preventing electrolyte leakage and blocking external contaminants from entering. Additionally, the lid may incorporate an integrated pressure relief valve that safely releases excess gas when internal pressure rises abnormally, thus averting potential explosions.
Expansion of the cover plate's functionality
In modern technology, the functionality of cover plates has been further enhanced. For instance, the "aluminum electrolytic capacitor with pressure detection," developed by Aiwa Group, features a pressure detector embedded in the cover plate, enabling real-time monitoring of internal pressure changes and providing early warnings before potential failures occur. This innovative design significantly improves the safety and reliability of the capacitor.
The Relationship Between the Cover Plate and Capacitor Performance
The sealing performance of the cover directly affects the lifespan and stability of the capacitor. If the seal is inadequate, the electrolyte will gradually dry out, leading to reduced capacitance or even complete failure. Therefore, automotive-grade aluminum electrolytic capacitors have even higher requirements for the temperature resistance (-55°C to +125°C) of the cover material and the sealing process, ensuring they can withstand harsh environments such as the engine compartment of a vehicle.
In summary, the aluminum electrolytic capacitor lid ensures the safe operation of the capacitor through physical sealing and functional integration—such as pressure detection—while its design must balance material weather resistance, sealing reliability, and electrical connection stability.
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