There are many ways to repair electric car battery, here are some common repair methods:

Hydration repair method. If the battery is short of water, you can use a dropper to inhale distilled water to be injected into the battery by the vent.
Particle generator repair method. Connect the particle generator in parallel to the battery to repair the battery, which can completely remove the possibility of battery sulfation and repair more thoroughly.
Activation repair method. Add appropriate amount of dilute electrolyte in the battery, change the distance between the two plates to get different discharge current, and then use the activation instrument for activation repair.
Re-assembling repair method. In the series battery group, the battery charge and discharge test, the battery discharge time difference of 5 minutes or less can be repaired by re-grouping.
Charging repair method. Leave the battery fully charged for 2 to 3 hours, then discharge it and leave it fully charged for another 2 to 3 hours, and repeat this process several times to help activate the active substances inside the battery and restore its performance.
In addition, there are also methods such as checking the electrolyte, charging with a small charge, activating with a fast charger and equalizing the charge can also repair the battery.

It should be noted that if the battery has been seriously aged or damaged, the above methods may not be able to repair it completely, and it is recommended to replace the battery with a new one to ensure the normal use of the electric vehicle. At the same time, we should also pay attention to the correct use and maintenance of the battery to extend its service life.