Given the same price, should you choose a ternary lithium battery or a lithium iron phosphate battery? Generally, ternary lithium batteries are preferred due to their better range and low-temperature resistance. However, this isn't a common choice under normal circumstances because there's a significant difference in manufacturing costs between lithium iron phosphate and ternary lithium batteries. Typically, mid-to-high-end electric vehicles use ternary lithium batteries, while mid-to-low-end electric vehicles use lithium iron phosphate batteries. The following details the differences between ternary lithium batteries and lithium iron phosphate batteries:
1. Ternary lithium has high energy density
The energy density of ternary lithium batteries is generally 180-230 Wh/kg, while high-nickel ternary lithium batteries can easily reach 250 Wh/kg. However, high nickel content increases battery instability. Lithium iron phosphate batteries, on the other hand, generally have an energy density of 140-160 Wh/kg, with the highest currently reaching 180 Wh/kg. Blade batteries also belong to the lithium iron phosphate category; for example, the first generation of blade batteries had an energy density of 140 Wh/kg, while the second generation may achieve 180 Wh/kg.
To be precise, battery energy density is divided into gravimetric energy density and volumetric energy density. The former is what we usually refer to, while the latter receives less attention but is equally important. For example, the innovative structure of the blade battery increased the volumetric energy density from 251Wh/L to 320Wh/L. Although its gravimetric energy density is not high, its driving range has caught up with that of ternary lithium batteries.
2. Ternary lithium batteries are more resistant to low temperatures.
Lithium-ion batteries become less effective at low temperatures. The low-temperature limit for lithium iron phosphate batteries is generally -20℃, while ternary lithium batteries can withstand temperatures as low as -30℃. Between 0 and -20℃, lithium-ion batteries experience a degradation of approximately 10%-30%, while ternary lithium batteries generally exhibit a degradation rate about 10% lower than lithium iron phosphate batteries. Currently, many automakers and battery manufacturers are developing more advanced thermal management technologies to improve the low-temperature performance of power batteries.
3. Lithium iron phosphate has a longer lifespan.
Ternary lithium batteries typically have a charge-discharge cycle life of 2000 cycles, while lithium iron phosphate batteries typically have 3000, about 1.5 times that of ternary lithium batteries. Battery life is not expressed in years, but rather in the number of charge-discharge cycles. For example, 2000 cycles means that the battery capacity decreases by less than 20% after 2000 charge-discharge cycles. In other words, after 2000 cycles, the battery capacity is equivalent to only 80% remaining; continued use will result in further capacity degradation.
4. Lithium iron phosphate is safer.
Through needle penetration tests, traditional lithium iron phosphate batteries produce no open flame but smoke, with surface temperatures reaching 200℃~400℃, while ternary lithium batteries experience an instantaneous temperature rise exceeding 500℃ after being punctured and begin to burn violently.
5. Lithium iron phosphate has a lower cost.
Previously, the average cost in the battery industry was 0.6 yuan/Wh for lithium iron phosphate batteries and 0.8 yuan/Wh for ternary lithium batteries. Based on a 60kWh battery, the cost of a ternary lithium battery was 48,000 yuan, while the cost of a lithium iron phosphate battery was 36,000 yuan, a difference of 12,000 yuan. Entering 2022, due to supply chain disruptions, particularly the significant price increases of nickel and cobalt, the cost of ternary lithium batteries surged, while the cost increase of lithium iron phosphate batteries was relatively smaller. Tesla even purchased blade batteries to reduce overall vehicle costs.
