Is the 4680 battery lithium iron phosphate? Overview of the advantages and disadvantages of 4680 batteries
The Tesla 4680 battery started in September 2020, represents the size of the battery, with a diameter of 46 mm and a height of 80 mm，and its specific performance, depends on the internal cell and positive and negative electrode performance. Tesla 4680 battery is currently using the ternary lithium battery technology route, but do not rule out the subsequent launch of lithium iron phosphate battery.
4680 belongs to ternary high nickel battery, cathode material is NCA (nickel cobalt aluminum), high nickel battery of three metals common ratio is 8:1.5:0.5. Nickel cobalt aluminum is three kinds of metal elements, so it is called "ternary lithium", ternary lithium is generally divided into NCA and NCM (nickel cobalt manganese).
4680 battery is also different from the mainstream battery in the cathode material, the mainstream is mainly graphite, 4680 battery uses a silicon-based anode, the material characteristic is higher specific capacity. However, there are some problems, such as easy volume expansion, poor electrical conductivity, and the first charge and discharge loss is large. In order to find a balance between the energy density and the stability, the current practice is to mix silicon and graphite.
In the process of 4680 Battery, the positive and negative electrode added PVDF coating, using more aluminum foil and copper foil to protect the electrode material, the conductivity is more sensitive. And the infinite ear design, the original positive and negative electrode connection of the glue reduced, cost reduction and efficiency, welding using laser technology.
Advantages and disadvantages of the 4680 batteries
It is 5.4 times larger than the previous 2170 cylindrical battery, the battery capacity is increased by 5 times, the vehicle range is increased by 16%, using the infinite ear design, the charging and discharge speed is increased by 6 times, which is expected to reduce the internal resistance of the battery to the original fifth, the heat production is lower and safer.
4680 is used with CTC scheme, that is, the cell is directly integrated into the chassis to improve the energy density of the battery system, reduce the vehicle weight, improve the production efficiency, and have more space for optimization in the ride;
The disadvantage is that it is impossible to determine whether there will be more difficult battery internal heat dissipation, cell expansion, resulting in the shortening of battery life.