Ternary lithium batteries are lithium salt batteries with nickel salt, cobalt salt, or manganese salt/lithium aluminate as the positive electrode material, graphite as the negative electrode material, and lithium hexafluorophosphate as the electrolyte. They possess excellent electrochemical characteristics such as high energy density, good safety and stability, and support for high-rate discharge, as well as economical cost advantages. They are widely used in small and medium-sized lithium batteries for consumer digital electronics, industrial equipment, and medical equipment, and are also used in power lithium batteries for intelligent robots, AGV logistics vehicles, drones, and new energy vehicles.
Lithium iron phosphate (LFP) batteries are lithium-ion batteries that use lithium iron phosphate as the positive electrode material. The negative electrode is also graphite. The electrolyte is also based on lithium hexafluorophosphate. Regardless of the battery's state, it can be charged and used at any time without needing to be discharged before charging. It is currently the safest lithium battery. Even if damaged internally or externally, the battery will not burn or explode, offering the best safety profile.
Comparison of data between ternary lithium batteries and lithium iron phosphate batteries
In the field of power batteries, lithium iron phosphate (LFP) batteries and ternary lithium batteries are technologically leading. While LFP batteries have a significantly lower energy density than ternary lithium batteries, their safety is generally considered superior. Due to the different performance characteristics and application scenarios of LFP and ternary batteries, both technologies will be supported simultaneously. LFP batteries offer advantages in high safety and long cycle life, meeting safety requirements. In the commercial vehicle sector, where operating frequencies are higher and space and weight constraints are more stringent, high-energy-density ternary lithium batteries can achieve longer driving ranges, meeting the needs of individualized consumers.
1. While lithium iron phosphate batteries are resistant to high temperatures, ternary lithium batteries have better low-temperature performance. This is the main technological route for manufacturing low-temperature lithium batteries. At -20°C, ternary lithium batteries can release 70.14% of their capacity, while lithium iron phosphate batteries can only release 54.94%. Furthermore, because the discharge platform of ternary lithium batteries is much higher than that of lithium iron phosphate batteries at low temperatures, their start-up speed is faster. The poor winter performance of lithium iron phosphate batteries is actually determined by their inherent characteristics.
The main reasons are:
Lithium iron phosphate (LFP) materials inherently possess low electrical conductivity, coupled with corresponding inherent low-temperature properties. The conductivity of (pure) LFP materials at room temperature can be at least four orders of magnitude lower than that of ternary materials. Although it is well known that LFP can achieve good room-temperature performance through carbon coating, this modification is not very effective, and LFP's performance at low temperatures remains excellent—therefore, in winter, ternary materials are inherently superior to LFP due to their superior conductivity.
The charge/discharge curves of lithium iron phosphate (LFP) materials are extremely flat, making them difficult for battery management systems (BMSs) to manage. This necessitates a large margin or production limits. While typical BMS current-capacity calibration is achieved through ampere-hour integration, it also requires calibration using the open-circuit voltage (OCV) versus capacity curve at the start/end of charge/discharge. However, the problem arises because LFP's curve is very flat, with a large, broad capacity range in the middle corresponding to a plateau around 3.2V. It's difficult to understand why current corrections are applied at 30/50/70% SOC. Therefore, our BMS engineers are forced to leave even more margin to handle potential extreme conditions (limiting the operating window), which further reduces the usable energy/power range of LFP…
2. Ternary lithium batteries have higher charging efficiency. Lithium battery charging uses a current-limiting and voltage-limiting method. In the first stage, constant current charging is performed, where the current is high and efficiency is high. After the constant current charging reaches a certain voltage, it enters the second stage of constant voltage charging. At this stage, the current is low and efficiency is low. Therefore, the ratio of constant current charging power to the total battery capacity is called the constant current ratio, used to measure the charging efficiency of the two. Experimental data shows that there is little difference between the two when charging below 10C, but the difference becomes significant above 10C. At 20C charging, the constant current rate of ternary lithium batteries is 52.75%, while that of lithium iron phosphate batteries is 10.08%, with the former being five times that of the latter.
3. In terms of cycle life, lithium iron phosphate batteries are superior to ternary lithium batteries. The theoretical lifespan of ternary lithium batteries is 2,000 cycles, but their capacity basically decays to 60% after 1,000 cycles; even the best brand in the industry, Sla, can only retain 70% of its capacity after 3,000 cycles, while lithium iron phosphate batteries retain 80% of their capacity after the same number of cycles.
