Can a swollen and overheated battery still be used?
2 Answers
If it only gets slightly hot and shows minor swelling during normal charging, there should be no immediate issue, but it's best to replace it with a new battery to ensure safety. Many electric vehicle fires are related to this. If the battery is swollen, it should not be used further as charging can be dangerous. Reasons for lead-acid battery swelling include: 1. Charger parameters: Mismatched charger parameters causing thermal runaway during charging, leading to battery swelling. 2. Quality issues: Problems with the internal battery cell groups, such as micro-shorts or lack of acid, can also cause thermal runaway and swelling.
I once encountered a swollen car battery. During a long drive, I suddenly smelled a sour odor. After pulling over, I found the battery was scalding hot and bulging like a balloon, which gave me quite a scare. Honestly, it absolutely cannot be used anymore because this indicates internal damage, likely caused by overcharging, a short circuit, or aging. Continuing to use it could lead to electrolyte leakage corroding car parts at best, or at worst, an explosion or fire—extremely dangerous. I immediately pulled over and called for roadside assistance, towing it to a repair shop for a new battery. The mechanic discovered the alternator had unstable voltage and fixed that too, solving the problem. Since then, I always ask technicians to check battery temperature and voltage during maintenance to prevent future issues. Remember, driving safety always comes first—don’t risk it to save money. A new battery costs just a few hundred bucks, far cheaper than repairing the whole car. Regularly cleaning terminal connections and checking electrolyte levels can also prevent this situation.
