Lithium battery charging and discharging test

The so-called overdischarge means that the battery continues to discharge after discharging the internal stored electricity and the voltage drops to a certain value, which causes overdischarge. Usually, the discharge cut-off voltage is determined according to the discharge current, that is, the critical voltage value for judging whether it is overdischarged or not. For a 3.7V lithium battery, 0.2C-2C discharge is generally set to 3.0V, and for those discharged above 3C, such as 5C or 10C discharge, it is set to 2.4V.

Overdischarge of batteries often brings disastrous consequences to batteries, especially over-discharge of large current or repeated over-discharge, which has a greater impact on the electrical performance of batteries. This is just like a person who loses three or five hundred milliliters of blood at a time, which will not affect his health, but once he loses too much blood, his normal body function will not be maintained, and if it reaches a certain level, he will die. As far as the battery is concerned, overdischarge will increase the internal pressure of the battery, and the reversible function of the positive and negative active materials will be destroyed. Even if it is remedied by charging, it is difficult to fully recover. Naturally, the capacity is obviously attenuated to a certain extent, and the battery "dies", and there is no way to bring it back to life.

In order to avoid excessive consequences, we should set the protection parameters in the early stage according to the characteristics of the battery, and in the later stage, we should strictly follow the "Regulations on the Use" of the battery in the instruction manual, and implement it with good quality and quantity. It is best to leave "residual charge" for the battery, just like "leaving a line for doing things so that we can meet again in the future". Laying a "foundation" for recharging is just like doing things. It is difficult to start from "zero" after all. We have been emphasizing that rechargeable battery is an applied science, and it is particularly important to use it. If it is used well, it will obey your orders, do its duty for you and serve you until you are satisfied, especially the highly active lithium-ion battery, which should be treated with care, otherwise, it will abandon you to a fierce horse that is difficult to tame, making you laugh and cry.