Battery bulging is a common irreversible fault caused by overcharging, which seriously affects battery service life and use safety of electric tricycles. During the overcharging process, the continuous input of electric energy makes the internal chemical reaction of the battery excessive and out of control. For lead-acid batteries commonly used in tricycles, overcharging will cause electrolysis of water in the electrolyte, producing a large amount of hydrogen and oxygen gas. These gases cannot be discharged in time in the sealed battery shell, resulting in continuous increase of internal air pressure. Meanwhile, excessive charging current will cause the battery temperature to rise sharply, further accelerating gas generation and thermal expansion, ultimately pushing the battery shell to bulge and deform.

For slightly swollen batteries with minor deformation and normal voltage output, targeted maintenance and corrective measures can be taken to restore partial performance and prevent further deterioration. First, stop using and charging the battery immediately, place it in a cool and ventilated environment to cool down completely, and avoid high-temperature exposure which will aggravate bulging. After cooling, use a professional battery detector to check the open-circuit voltage and capacity of each cell to confirm whether the internal plates are severely damaged. Then replace the original ordinary charger with an intelligent automatic power-off charger with overcharge protection, constant current and constant voltage functions, to avoid repeated overcharging caused by inaccurate charging voltage of inferior chargers.

For severely swollen batteries with obvious deformation, unstable voltage or bulging shell gaps, direct replacement is the only safe solution, as such batteries have internal plate deformation, electrolyte loss and potential short-circuit risks, and cannot be repaired completely. To prevent overcharging and bulging again in daily use, users must standardize charging habits. The charging time of tricycle lead-acid batteries should be controlled within 8 to 10 hours, and do not charge overnight or for more than 12 hours for a long time. In addition, regularly check the charger’s operating status, replace aging and faulty chargers in time, and avoid charging the battery in high-temperature environment, so as to fundamentally eliminate overcharging-induced bulging failure.