Lithium battery overcharged and discharged

The rated voltage of a lithium ion battery is generally 3.7V due to material changes, while the positive electrode of lithium iron phosphate (hereinafter referred to as ferrophosphate) is 3.2V. The international standard for terminating charging voltage when fully charged is 4.2V and 3.6V for ferrophosphate. The termination discharge voltage of lithium ion batteries is 2.75V to 3.0V (domestic battery manufacturers provide a working voltage range or a termination discharge voltage, with slightly different parameters, generally 3.0 to 2.75V, and 2.5 V for ferrophosphate.). Continued discharge below 2.5 V (2.0 V for ferrophosphate) is called overdischarge (the international standard is a minimum of 3.2 V for ferrophosphate 2.8 V). Overdischarge or self-discharge reactions at low voltages can lead to decomposition and destruction of lithium ion active substances, which may not necessarily be reducible. Any form of overcharging of lithium ion batteries can cause serious damage to battery performance, even explosion. During the charging process of lithium ion batteries, it is necessary to avoid overcharging the batteries.