The working principle of lithium iron phosphate battery

The full name of lithium iron phosphate battery is lithium iron phosphate lithium ion battery, abbreviated as lithium iron phosphate battery. Because its performance is particularly suitable for power applications, the word "power" is added to the name, that is, lithium iron phosphate power battery. Some people also call it "lithium iron (LiFe) power battery".

significance
In the metal trading market, cobalt (Co) is the most expensive, and there is not much storage, nickel (Ni) and manganese (Mn) are cheaper, and iron (Fe) is the cheapest. The prices of cathode materials are also in line with those of these metals. Therefore, lithium-ion batteries made of LiFePO4 cathode material should be the cheapest. Another feature of it is that it does not pollute the environment.
As a rechargeable battery, the requirements are: high capacity, high output voltage, good charge and discharge cycle performance, stable output voltage, high current charge and discharge, electrochemical stability, and safety in use (not due to overcharge, overdischarge and short circuit) It can cause combustion or explosion due to improper operation), wide operating temperature range, non-toxic or less toxic, and no pollution to the environment. The lithium iron phosphate battery using LiFePO4 as the positive electrode has good performance requirements, especially in terms of large discharge rate discharge (5-10C discharge), stable discharge voltage, safety (non-burning, non-exploding), life (cycle times) ), in terms of no pollution to the environment, it is the best and the best high-current output power battery at present.

Structure and working principle
The internal structure of the LiFePO4 battery is shown in Figure 1. On the left is the peridot structure

LiFePO4 is used as the positive electrode of the battery. It is connected to the positive electrode of the battery by an aluminum foil. The middle is a polymer separator, which separates the positive electrode from the negative electrode, but the lithium ion Li+ can pass through but the electron e- cannot pass through. The right side is composed of carbon (graphite). The negative electrode of the battery is connected to the negative electrode of the battery by copper foil. Between the upper and lower ends of the battery is the electrolyte of the battery, and the battery is hermetically sealed by a metal casing.

When LiFePO4 battery is charged, the lithium ion Li+ in the positive electrode migrates to the negative electrode through the polymer separator; during the discharge process, the lithium ion Li+ in the negative electrode migrates to the positive electrode through the separator. Lithium-ion batteries are named after lithium ions migrate back and forth during charging and discharging.