Reasons for the decrease in battery capacity:

1. Batteries are aging and declining.

2. The self-discharge rate is different, resulting in unbalanced battery cells in series, which ultimately leads to a decrease in battery capacity and durability.

3. During the battery use and charging and discharging process, the phenomenon of "vulcanization" will affect the battery capacity.

The vulcanization performance of the battery is: the battery itself is low in voltage, it will be full after charging, and it will be gone after discharge.

The battery softening performance is: the liquid inside the battery is turbid and black. The battery capacity decreases, and the lead powder falls off after a long time.

4. Improper charging in summer and winter. The battery charging voltage is inversely proportional to the ambient temperature, so the summer temperature is high, and the battery overcharge causes the battery to lose water, causing the battery to swell and deform. In winter, the driving mileage decreases due to undercharge.
Battery repair method:

There are generally two methods, repair machine repair and battery refurbishment. Batteries with broken grids, broken poles, perforations, etc. cannot be repaired with a repair machine, and can only be repaired through refurbishment.

1. The battery is aging, and there is no way to repair it at the end of its life.

2. The battery pack has different self-discharge rates and inconsistent voltages. Then first detect which battery is of a different voltage, and then replace the battery with the normal battery pack capacity, voltage, self-discharge, battery internal resistance, etc. and use it together.

3. For vulcanization problems, use "high current, high voltage" equipment to remove vulcanization.

4. In summer, charging cannot be placed in an exposed location or overcharged. In winter, when not in use for a long time, the electric vehicle should be charged regularly, usually at least once a month.