Charge Discharge Principle Of Lithium Iron Phosphate Battery

Lithium iron phosphate battery is a kind of lithium ion battery that uses lithium iron phosphate (LiFePO4) as cathode material and carbon as cathode material. The rated voltage of the single battery is 3.2V, and the charging cutoff voltage is 3.6V~3.65V.
During the charging process, some lithium ions in lithium iron phosphate are removed and transferred to the negative electrode through the electrolyte, which is embedded in the negative electrode carbon material; At the same time, electrons are released from the positive electrode and reach the negative electrode from the external circuit, maintaining the balance of chemical reactions.
During the discharge process, lithium ions detach from the negative electrode and reach the positive electrode through the electrolyte. At the same time, the negative electrode releases electrons, which reach the positive electrode from the external circuit and provide energy to the outside world.
The charge discharge reaction of lithium iron phosphate battery is carried out between LiFePO4 and FePO4. During the charging process, LiFePO4 gradually separates from lithium ion to form FePO4. During the discharge process, lithium ion is embedded in FePO4 to form LiFePO4.
When the battery is charged, lithium ions migrate from the lithium iron phosphate crystal to the surface of the crystal, enter the electrolyte under the action of electric field force, pass through the separator, and then migrate to the surface of the graphite crystal through the electrolyte, and then embed into the graphite lattice.
At the same time, electrons flow through the conductive body to the aluminum foil collector of the positive electrode, through the electrode ear, battery positive pole, external circuit, negative pole pole, and negative pole ear to the copper foil collector of the negative electrode of the battery, and then through the conductive body to the graphite negative electrode, so that the charge of the negative electrode reaches equilibrium. After lithium ions are removed from lithium iron phosphate, lithium iron phosphate is converted into iron phosphate.
When the battery is discharged, lithium ions detach from the graphite crystal, enter the electrolyte, pass through the separator, migrate to the surface of the lithium iron phosphate crystal through the electrolyte, and then re embed into the lattice of the lithium iron phosphate crystal.
At the same time, electrons flow through the conductive body to the copper foil collector of the negative electrode, through the electrode ear, battery negative pole, external circuit, positive pole, and positive pole ear to the aluminum foil collector of the positive electrode of the battery, and then through the conductive body to the lithium iron phosphate positive electrode, so that the charge of the positive electrode reaches equilibrium. After lithium ions are embedded into iron phosphate crystals, iron phosphate is converted into lithium iron phosphate.