The difference between lithium iron phosphate battery and lithium ternary battery

Date:2019-04-01 16:58
After years of development, the current types of lithium batteries include lithium manganese oxide, lithium iron phosphate, lithium titanate, lithium cobalt oxide, ternary materials, etc. Due to energy performance and rare metal costs, lithium manganese oxide, lithium titanate, and lithium cobalt oxide batteries have gradually become niche choices, while lithium iron phosphate and ternary lithium batteries have been more widely promoted and applied. But what is the difference between the two? What kind of battery is your car equipped with? Today we will talk about lithium batteries.

Ternary lithium battery
The full name of ternary lithium batteries is "ternary material batteries", which generally refers to lithium batteries using nickel cobalt manganese oxide (Li (NiCoMn) O2, NCM) or nickel cobalt aluminate lithium (NCA) ternary cathode materials. Nickel salt, cobalt salt, and manganese salt are adjusted in different proportions as three different components, so they are called "ternary" and include many types of batteries with different proportions. From the perspective of shape, it can be divided into soft pack batteries, cylindrical batteries, and square hard shell batteries. Its nominal voltage can reach 3.6-3.8V, with high energy density, high voltage platform, high vibration density, long range, large output power, poor high-temperature stability, but excellent low-temperature performance and high cost.

Lithium iron phosphate battery
Lithium iron phosphate batteries use lithium iron phosphate (LiFePO4) as the positive electrode material. Using iron as the raw material for the battery is cost-effective, does not contain heavy metals, and has less environmental pollution. The working voltage is 3.2V. The P-O bond in lithium iron phosphate crystal is stable, so there will be no leakage during zero voltage storage. It has high safety under high temperature conditions or overcharging, and can be quickly charged. It has high discharge power, no memory effect, and long cycle life. The disadvantages are poor low-temperature performance, low vibration density of the positive electrode material, low energy density, and the product yield and consistency are also questioned.

These two types of batteries each have their own strengths
Under high temperature conditions, the ternary materials of ternary lithium batteries will undergo decomposition at 200 ℃, leading to intense chemical reactions, releasing oxygen atoms, and being prone to combustion or explosion under high temperature conditions. Therefore, for safety reasons, the Ministry of Industry and Information Technology of China temporarily restricted the use of ternary lithium batteries to pure electric buses through special regulations in January 2016. The decomposition temperature of lithium phosphate batteries is at 800 ℃, making them less prone to ignition and relatively safe.

Under low temperature conditions (temperatures below -10 ℃), lithium phosphate batteries decay very quickly. After less than 100 charging and discharging cycles, the battery capacity will decrease to 20% of the initial capacity, which is basically insulated from use in cold regions; The ternary lithium battery has excellent low-temperature performance and can maintain normal battery capacity at -30 ℃, making it more suitable for the use conditions in low-temperature areas in the north.

From the perspective of manufacturing costs, the cobalt element necessary for ternary lithium batteries is relatively scarce in China, and most of it is imported from overseas, which is greatly affected by market fluctuations. Therefore, the cost of ternary lithium batteries is inevitably high, while the raw materials required for lithium iron phosphate batteries do not need to be imported, with sufficient supply, stable prices, and relatively low costs.