Why is there a voltage difference in lithium iron phosphate batteries?

It is normal for the charging and discharging platform of lithium iron phosphate batteries to have a voltage difference. Although it can withstand overcharging, charging to a higher voltage will still damage the battery. The reason is that lithium iron phosphate battery is a lithium-ion battery that uses lithium iron phosphate (LiFePO4) as the positive electrode material and carbon as the negative electrode material. The rated voltage of the single cell is 3.2V, and the charging cutoff voltage is 3.6V~3.65V.

On the left side of the lithium iron phosphate battery is the positive electrode composed of LiFePO4 material with olivine structure, which is connected to the battery positive electrode by aluminum foil. On the right is the negative electrode of the battery composed of carbon (graphite), which is connected to the negative electrode of the battery by copper foil. In the middle is a polymer separator, which separates the positive and negative electrodes. Lithium ions can pass through the separator while electrons cannot. The battery is filled with electrolyte inside and sealed with a metal casing.

The charging and discharging reactions of lithium iron phosphate batteries occur between LiFePO4 and FePO4 phases. During the charging process, LiFePO4 gradually separates from lithium ions to form FePO4. During the discharge process, lithium ions are embedded in FePO4 to form LiFePO4.

Guangzhou Battsys Co., Ltd (NEEQ:837375), was founded in 2006, which is a join-stock high-tech enterprise engaging in ODM and OEM , specially for customized and diverse research&production of lithium-ion battery，BATTSYS annual production capacity is tens of millions battery cells. The products are exported to dozens of countries & regions such as Europe, America & Asia etc.