NCM Lithium ion Battery Advantages&Disadvantages
The NCM lithium ion battery refers to a lithium battery containing the three elements of nickel cobalt and manganese, which is in line with the positive electrode of the material, and can be expressed as LiMnxNiyCo1-x-yO2 (0<x<0.5,0<y<0.5) by the general formula. This material combines the advantages of three materials such as lithium cobalt acid lithium, lithium nickel and lithium manganate, forming a three phase eutectic system of three materials, which is better than any single compound because of the synergistic effect of three elements. The weight energy density can reach 200Wh/kg.
But the safety of NCM lithium ion battery is poor. The thermal stability of NCM lithium ion battery is poor, and it will break down at 250-300 C. When the battery is combustible and carbon material is on the point, the heat generated will further intensify the positive decomposition, and it will deflagration in a very short time. In a car accident, a force impact will damage the battery diaphragm and lead to a short circuit, and the heat emitted by the short circuit causes the battery to run out of control and rapidly increase the temperature to more than 300 degrees centigrade, and there is a risk of spontaneous combustion. Therefore, for the NCM lithium ion battery, its battery management system and cooling system are very important.
In order to improve the safety of the product, the material with strong heat resistance is used, the pressure relief valve is used to control the pressure in the battery, the current of the battery is controlled actively, and the battery charge state is monitored in real time, and the circuit can be forced to cut off the current circuit to improve the safety. These are feasible measures to improve the safety of NCM lithium ion battery.
For safety reasons, passenger cars with lithium-ion batteries can not enter the Ministry of Industry and Information Technology's new energy vehicle catalogue, while cars and trucks are not affected. Although there is security concerns, but because of the policy on the energy density, NCM lithium ion battery has shown the trend of replacing the lithium iron phosphate battery, becoming the mainstream of passenger cars.
Of the 296 new energy passenger cars announced by the Ministry of Industry and Information Technology in 2017, 221 were made of lithium-ion batteries, while only 33 were made of lithium iron phosphate. BYD has been the leader of the domestic lithium iron phosphate battery, but since 2016, the new energy vehicles under the flag, including all PHEV passenger cars, such as Qin and Tang and so on, have started to match three yuan lithium batteries, only the bus still uses lithium phosphate. Its resources are also inclined to NCM lithium ion battery, NCM lithium ion battery capacity of 6GWh and 8GWh of lithium iron phosphate battery, and NCM lithium ion battery capacity of new Qinghai plant will be 18GWh.
So far, three yuan and lithium phosphate batteries have not yet been able to win or lose, and three yuan lithium batteries take up the upper wind, but both are at least a perfect solution at the present stage, and other alternative energy technologies, such as graphene or fuel cells, are all covetous.