We often talk about NCM batteries or LFP batteries, which are named according to anode materials. This article summarizes 4 common types of lithium batteries and their main performance parameters. As we all know, the same technology line of the cell, the specific parameters are not the same. This paper shows the current parameters of the general level. 4 types of lithium batteries specifically include LCO, NCM, LFP, and LTO titanate battery.
Its high specific energy density makes lithium cobalt a popular choice for mobile phones, laptops, and digital cameras. The battery consists of a cobalt oxide cathode and a graphite carbon anode. The Cathode has a layered structure, during discharge, lithium ions move from anode to cathode and flow in the opposite direction during charging.
The disadvantages of lithium cobalt oxide are its relatively short life, low thermal stability, and limited load capacity (specific power). Like other cobalt lithium-ion batteries, lithium cobalt oxide uses graphite anode, and its cycle life is mainly limited by the conductor interface (Sei), mainly manifested by the gradual thickening of Sei film, and fast charging or low temperature charging process anode lithium plating problem. Newer material systems have added nickel, manganese, and/or aluminum to improve life, load capacity, and reduce costs.
Lithium Cobalt Oxide performs well in terms of high energy density, but only provides general performance in terms of power characteristics, safety, and cycle life. Because of the high cost of cobalt and the obvious performance improvement by mixing with other active cathode materials, lithium cobalt oxide is gradually replaced by NCM.
The secret of the NCM is the combination of nickel and manganese. Similarly to table salt, the main ingredients, sodium, and chloride are themselves toxic, but they are mixed as flavoring salts and food preservation agents. Nickel is famous for its high specific energy, but its stability is poor; manganese spinel structure can realize low internal resistance but low specific energy. The two active metals complement each other.
The NMC is the preferred battery for electric tools, electric bikes, and other electric power systems. The cathode combination is usually five parts nickel, three parts cobalt, and two parts Manganese (5-3-2). Different combinations of cathode materials can also be used.
Because of the high cost of cobalt, battery makers have shifted from cobalt to nickel cathodes. Nickel-based systems have a higher energy density, lower cost, and longer cycle life than cobalt-based batteries, but their voltages are slightly lower.
The new electrolytes and additives allow a single battery to charge to more than 4.4 v, increasing the charge.
Lithium Iron Phosphate (LIFEPO4)
In 1996, the University of Texas discovered phosphate as a cathode material for rechargeable lithium batteries. Lithium phosphate has good electrochemical properties and low resistance. This is done by means of nanoscale phosphate cathode materials. The main advantages are high rated current and long cycle life; good thermal stability enhanced security and tolerance to abuse.
If kept at a high voltage for a long time, lithium phosphate is more resistant to all charging conditions and has less stress than other lithium-ion systems. The downside is that the lower nominal voltage of the 3.2 v Battery makes the specific energy lower than that of the cobalt doped lithium-ion battery.
For most batteries, low temperatures reduce performance, and higher storage temperatures shorten life, and lithium phosphate is no exception. Lithium phosphate has a higher self-discharge rate than other lithium-ion battery, which may cause aging and lead to equalization problems, although this can be remedied by selecting high-quality batteries or using advanced battery management systems, both methods add to the cost of the battery pack. Battery life is very sensitive to impurities in the manufacturing process, can not withstand water doping, due to the existence of water impurities some batteries only have the shortest life of 50 cycles.
Lithium phosphate has good safety and long life, moderate specific energy, self-discharge ability.
Lithium Titanate Battery (Li4ti5o12)
Lithium titanate batteries have been known since the 1980s. Lithium titanate replaces graphite in the typical lithium-ion battery anode, and the material forms a spinel structure. The Cathode can be either lithium manganate or NMC. The lithium titanate battery has a nominal voltage of 2.40 V and can be charged quickly, providing a high discharge current of 10C. It is said that the number of cycles is higher than that of the conventional lithium-ion battery, can reach 10,000~20,000 cycles. Lithium titanate is safe, has excellent low-temperature discharge characteristics, and can achieve 80% capacity at-30 ° C (- 22 ° F).
LTO thermal stability at high temperatures is better than that of other Lithium-ion Systems; however, batteries are expensive. Low specific energy, only 65 wh/kg, equivalent to NICD. Lithium titanate is charged to 2.80 V and discharged to 1.80 v.
Lithium titanate performs well in terms of safety, low-temperature performance, and cycle life. Efforts are being made to increase specific energy and reduce costs.
SmartPropel Original Work Writer:Nancy