What are the causes of battery leakage?

[StLilah]

Battery leakage causes: 1. Cracks in appearance, poor sealing between the upper cover and the base tank, or cracking of the sealing glue due to collision, resulting in battery leakage; 2. Acid leakage from the cap valve; 3. Acid leakage from the terminal; 4. Acid leakage from other parts. Inspection and treatment of battery leakage faults: 1. Perform an appearance inspection to identify the acid leakage location; 2. Remove the cover plate to check for traces of acid leakage around the cap valve, then open the cap valve to observe whether there is any flowing electrolyte inside the battery; 3. If no abnormality is found, perform an airtightness test by placing the battery in water and inflating it under pressure, observing whether bubbles are generated and emerge from the battery. Bubbles indicate acid leakage; 4. During the charging process, observe whether any flowing electrolyte is produced. If there is, it indicates a production-related issue. If flowing electrolyte is found during charging, it should be completely drained.

[McEvan]

I've been driving for over twenty years and have seen many cases of battery leakage. The most common cause is battery aging; over time, the internal electrolyte dries up or depletes too quickly, and the separator deforms, leading to leakage. Another reason is overcharging—either the generator voltage is too high or an improper charger is used, causing the battery to overheat, expand, and leak. Last time, my neighbor's car frequently had insufficient charge after short trips, and when parked in a hot parking lot, the electrolyte contracted unevenly and leaked. Physical damage can't be ignored either, such as hitting a hard object on bumpy roads, cracking the casing. To prevent these issues, I recommend regularly checking the battery's fluid level and appearance, using high-quality parts instead of cheap ones. If leakage is spotted, address it immediately—otherwise, corrosion on the car frame is a nightmare. Now, I proactively replace my battery every two years for peace of mind.