When the battery is charged, the lithium atoms on the positive electrode are ionized into lithium ions and electrons (deintercalation). Lithium ions move to the negative electrode through the electrolyte and obtain electrons. The electrons are reduced to lithium atoms and inserted into the micropores of the carbon layer (penetration).
When the battery is discharged, the lithium atoms inserted in the carbon layer of the negative electrode lose electrons (delamination) and become lithium ions, and then return to the positive electrode (intercalation) through the electrolyte.
The charging and discharging process of a lithium ion battery is a process of continuous insertion and stripping of lithium ions between the positive electrode and the negative electrode, accompanied by the insertion and stripping of equivalent electrons. The more lithium ions, the stronger the charge and discharge capacity.
Due to the difference in positive electrode data, lithium ion batteries are mainly divided into lithium iron phosphate (LFP), lithium nickel oxide (LNO), lithium manganese oxide (LMO), lithium cobalt oxide (LCO), lithium NCM (NCM), and nickel nickel aluminate Lithium (NCA).
Let's take a look at the different types of lithium ion batteries on the market.
First of all, lithium cobalt oxide, as a pioneer of lithium ion batteries, can also be used as a power lithium battery to test water. This is the first time a Tesla sports car has been used, but due to its low cycle life and safety, it is not suitable as a Power lithium battery. In order to make up for this shortcoming, Tesla used the world's best battery management system to ensure battery stability. Lithium cobalt oxide is now an important player in the 3C market.
The second type is lithium manganate, originally proposed by the battery company AESC. AESC is a joint venture between Nissan and NEC. The representative model of lithium manganese oxide is Nissan leaf. Because of its low price, medium energy density and general safety, it has the so-called better sensing function. Because of its tepid nature, it is gradually being replaced by new skills.
In addition, BYD’s flagship product, li-ironphosphate, has stable performance, long life, and cost advantages, especially for plug-in hybrid vehicles that need to be continuously charged and discharged, but its energy density is not high.
The final result is a ternary lithium-ion battery, which is a new star with the highest energy density but relatively poor safety. Regarding the scope of requirements for pure electric vehicles, its vision is broader, which is the mainstream direction of power lithium batteries.
The following is the MODEL3 announced by Tesla in July, which uses 21,700 ternary (NCA) cylindrical batteries from Panasonic.
In fact, in the power lithium battery market, there is a technology path competition among the three giants of my country, Japan and South Korea. In the so-called Romance of the Three Kingdoms, they are all recruiting, expanding their territories, and fighting to reach the top of the mountain. Our next article will focus on this issue, so please stay tuned.