What are the disadvantages of overcharge and undercharge of electric vehicle batteries?
Overcharge means that the charging current of the battery is greater than the acceptable current of the battery, and the excess part is the overcharge amount. Overcharge mainly produces the side reaction of electrolytic water. As the oxygen generated by the positive electrode of the battery is transferred to the negative electrode to produce oxygen compound reaction, heat will occur. Therefore, the overcharge amount is actually converted into heat to increase the battery temperature. If it is not controlled, it will cause a large amount of water loss, In serious cases, it will cause "heat out of control", sharp reduction of capacity, and even deformation.
Generally speaking, under charging means that when the battery is not fully charged and is often under charged, it will gradually form a kind of thick and hard lead sulfate, which is almost insoluble, that is, the so-called "irreversible sulfation", which can not be charged by ordinary methods, so the capacity will decay rapidly time by time.