It is not recommended to fully charge ternary lithium batteries.
Many people online say that lithium iron phosphate batteries should be fully charged, while ternary lithium batteries only need to be charged to around 90% and not fully charged. The reason given is that a fully charged lithium battery will have a higher voltage, which affects the activity of the electrolyte and the positive and negative electrode materials, leading to a decrease in battery capacity. At the same time, ternary lithium batteries are also not suitable for over-discharging; it's best to recharge them when the remaining charge is around 30%.
Advantages and disadvantages of ternary lithium batteries
The advantage of ternary lithium batteries is that their energy density per unit volume is higher than that of lithium iron phosphate batteries. With the same energy density as lithium iron phosphate batteries, ternary lithium batteries are smaller in size, and the same size ternary lithium batteries can provide longer driving range.
In addition, ternary lithium batteries have better cycle charge and discharge performance, and can be cycled more than 2,000 times under normal conditions. In addition, ternary lithium batteries have high energy density, so the charging frequency is relatively lower, which means that the service life is longer.
Another advantage is that ternary lithium batteries are not afraid of the cold, so their battery life does not drop as much as that of lithium iron phosphate batteries in winter.
In ternary lithium batteries, the active lithium reacts with the electrolyte, releasing heat. Therefore, a drawback of this type of battery is its tendency to overheat. However, as long as the charging current is not too high, and the battery has a cooling system, the heat released from the reaction does not pose a significant threat.
However, the current obsession with shortening charging time and the ever-increasing charging power of fast charging have led to a situation where the rate at which the battery generates heat far exceeds the rate at which it dissipates heat. High temperatures cause lithium ions to precipitate too quickly, forming dendritic crystals. These crystals can pierce the separator between the positive and negative electrodes, creating a short circuit and generating high temperatures within a short period, potentially leading to spontaneous combustion.
Currently, the biggest factor restricting the use of ternary lithium batteries is the high production cost, including the high cost of raw materials and thermal management systems, which leads to a higher price for the entire vehicle. Coupled with limited subsidies, the cost is passed on to consumers, meaning that ternary lithium batteries are currently mainly used in mid-to-high-end pure electric vehicles.
