NMC Batteries: properties and usage
NMC stands for Lithium Nickel Manganese Cobalt Oxide battery. (LiNiMnCoO2)
The cathode combination of NMC (nickel-manganese-cobalt) is among the most successful Li-ion systems. The NMC systems can serve as a Power Cell or an Energy Cell.
Lithium-ion batteries and concept
The most popular technology of the battery sector currently is the lithium ion battery. Relative to other types of batteries, lithium ion batteries have better energy, power density and higher cycling ability. These qualities are extremely important in the use in modern applications like electrical and hybrid vehicles and most importantly energy storage systems which are used in the renewable energy applications.
The lithium ion batteries chemistry is the same across the different lithium-ion battery types; during discharge, Lithium-ions move to the positive cathode from the negative anode through the organic electrolyte. The anodes in all various technologies of lithium ion are all made from graphite. The differences are the cathode which contains changing cobalt, nickel or manganese concentrations. All various cathode types allow high lithium insertion and intercalation levels which result in large energy storage quantities. The name Lithium-ion is after the active materials; it can be either expressed by words or shortened by the chemical symbols.
NMC batteries technology and applications
NMC (Nickel Manganese Cobalt Oxide) battery was invented in the year 2008. Its anode material is LiaC6, the cathode material is LibNi1–x–yCoxMnyO2 and the carrier is Li+. They commonly use it in different applications like Energy Systems and electric cars.
NMC combines the best of nickel and manganese. Nickel has high specific energy but poor stability; manganese can form a spinel structure so as to achieve low internal resistance yet provides a low specific energy. Joining the metals increases the strengths from both parts.
NMC batteries are widely used for power tools, energy storage systems (EES) which need frequent cycling and electrical power-trains like automotives. The cathode combination typically used is 1-1-1 which means one third nickel, one third manganese and one third cobalt. This reduces the raw material cost due to lowered content of cobalt. Another known combination for NCM is 5-3-2 (5 parts nickel, 3 parts cobalt and 2 parts manganese). Other combinations are also possible
Advantages and disadvantages of NMC batteries
The main advantages of the NMC batteries are:
- NMC cells provide longer life cycle
- Lower cost
- Higher energy density
- NMC cathodes contain the most energy amount by weight and volume.
The main disadvantages of the NMC batteries are:
- Adding silicon to graphite has the downside of making the anode grow and shrink through charging and discharging, leading to mechanical instability of the cell.
- Slightly lower voltage than cobalt systems