Analysis of correct charging of lithium iron phosphate battery

There are many ways to charge lithium iron phosphate batteries, which can be divided into regular charging and fast charging according to the charging efficiency. Among them, the conventional charging methods of lithium iron phosphate batteries include: constant current charging, constant voltage charging, stage charging and intermittent charging, while fast charging includes pulse charging and Reflex charging, and finally the smart charging is decomposed. 1. Constant current charging lithium iron phosphate batteries according to the size of the charging current constant current charging can be divided into fast charging, standard charging and trickle charging. During the whole charging process, generally adjust the charging voltage of the power supply or change the resistance value in series with the battery to maintain the charging current of the battery unchanged. This method has the advantage of simple control and is suitable for charging lithium iron phosphate batteries connected in series with multiple batteries. The disadvantage is that the acceptable charging capacity of the lithium iron phosphate battery will gradually decrease as the charging progresses, and the excessive charging current in the later stage of the charging will cause bubbles to appear in the lithium iron phosphate battery and cause damage to the lithium iron phosphate battery. Therefore, constant current charging is often used as a link in stage charging. 2. Constant voltage charging Constant voltage charging means that during the entire charging process, the charging voltage remains constant, and the charging current is automatically adjusted as the battery status changes. As the lithium iron phosphate battery is charged, the charging current of the lithium iron phosphate battery gradually decreases. Compared with constant current charging, the charging process is closer to the optimal charging curve, and the control is simple and the cost is low. 3. Constant current and constant voltage charging is a constant current and constant voltage charging curve. Before starting charging, first test the voltage of the lithium iron phosphate battery. If the voltage of the lithium iron phosphate battery is lower than the threshold voltage (about 2.5V), trickle charge the battery with a small current of C/10 to make the battery voltage rise slowly; When the voltage of the lithium iron phosphate battery reaches the threshold voltage, it enters constant current charging. At this stage, the battery is quickly charged with a larger current (0.5C ~ 1C). The voltage of the lithium iron phosphate battery rises faster, and the lithium iron phosphate battery The capacity will reach about 85% of its rated value; after the battery voltage rises to the upper limit voltage (4.2V), the circuit switches to constant voltage charging mode, the battery voltage is basically maintained at 4.2V, the charging current gradually decreases, and the charging speed becomes slower At this stage, it is important to ensure that the lithium iron phosphate battery overflows. When the charging current of the lithium iron phosphate battery drops to 0.1C or 0.05C, it is judged that the lithium iron phosphate battery overflows. Disclaimer: Some pictures and content of articles published on this site are from the Internet. If there is any infringement, please contact to delete. Previous: What are the recycling methods for lithium iron phosphate batteries?