The charge and discharge reaction of the lithium iron phosphate battery is carried out between the two phases of LiFePO4 and FePO4. During the charging process, LiFePO4 gradually breaks away from lithium ions to form FePO4, and during the discharging process, lithium ions intercalate into FePO4 to form LiFePO4.
When the battery is charging, lithium ions migrate from the lithium iron phosphate crystal to the surface of the crystal, enter the electrolyte under the action of the electric field force, then pass through the diaphragm, migrate to the surface of the graphite crystal through the electrolyte, and then embed in the graphite lattice.
At the same time, electrons flow through the conductor to the aluminum foil collector of the positive electrode, through the tab, the positive pole of the battery, the external circuit, the negative pole, and the tab of the negative pole to the copper foil current collector of the negative pole of the battery, and then through the conductor to the graphite negative electrode , so that the negative charge balance. After lithium ions are deintercalated from lithium iron phosphate, lithium iron phosphate is converted into iron phosphate.
When the battery is discharged, lithium ions are deintercalated from the graphite crystal, enter the electrolyte, then pass through the diaphragm, migrate to the surface of the lithium iron phosphate crystal through the electrolyte, and then re-intercalate into the lattice of lithium iron phosphate.
At the same time, electrons flow through the conductor to the copper foil collector of the negative electrode, through the tab, the negative pole of the battery, the external circuit, the positive pole, and the positive tab to the aluminum foil collector of the positive pole of the battery, and then through the conductor to the iron phosphate The lithium positive electrode balances the charge of the positive electrode. After lithium ions are intercalated into the iron phosphate crystal, the iron phosphate is converted into lithium iron phosphate.