What are the reasons for battery bulge?

Three minutes will let you understand why the battery is swollen. When many people feel that the battery in their car has a problem, after removing the battery pack and opening it, they will find that the battery is swollen, sometimes even severely deformed. Although some of these batteries have only been used for more than a year, and some are even under warranty, why is this happening? In fact, there are not a few particularly mysterious things in this, don't you believe it? Then look down, two minutes is enough: Reason 1: When the battery is charging, the lead sulfate on the positive and negative plates and the water in the electrolyte are chemically reacted, so that the positive plate is reduced to lead oxide, and the negative plate is reduced. The chemical equation is as follows: (charge reaction) when the battery cell voltage reaches 2.3V or more, the battery will release gas (the gassing voltage of the lead-calcium plate is 2.3V, and the gassing voltage of the lead-antimony plate is 2.3V. 2.35V). Everyone knows that when the water is boiled, the water vapor is very hot, and at the same time it is very powerful, and it can start a train (steam car). This theory is the same for our batteries. When gas is gassed, the temperature of the battery will increase. At the same time, if a large amount of gas is gassed, there will be insufficient space inside the battery to store the gas, which will cause the battery to swell. Reason 2: The internal resistance of the battery is too high. When the internal resistance of a battery is too high, when the current is constant, the voltage will be very high (voltageu003dcurrent*resistance). What we can see is that the battery is very hot before the red light jumps during normal charging, that is, the battery has not reached the charging voltage, and it gassed in advance! Reason three: The electric vehicle charger does not meet the requirements. When the parameters of the electric vehicle charger we use are higher than the rated voltage and current of our battery, it is possible to charge the battery! Disclaimer: Some pictures and content of the articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous article: Which factors will affect the price of 18650 lithium battery pack?