Chemically and performance-wise, lifepo4 batteries’ normal working temperature is -20°C to 60°C, with the optimal working temperature being 15°C to 35°C. Their discharge efficiency is ≥95% in this temperature range, whereas the capacity fading rate is as low as 0.02% per cycle (0.1% for lead-acid batteries). For instance, Tesla Powerwall (based on lifepo4 technology) has a cycle life of up to 6,500 times (capacity retention rate ≥80%) at a constant temperature of 25°C, but its life drops to 5,500 times at 0°C, with a decrease rate of approximately 15%. Tests conducted by the U.S. Department of Energy in 2023 prove that under the condition of temperature higher than 50°C, the capacity decay rate of lifepo4 accelerates to 0.05% per cycle, but still superior to 0.12% per cycle of ternary lithium batteries.
In the low-temperature adaptability aspect, lifepo4 discharge efficiency can still be 90% at -20°C (that of lead-acid batteries is only 40% at 0°C), and the cell temperature can be raised from -30°C to -10°C within 12 minutes by the internal heating film (power consumption ≤5W). The Norwegian Northern Lights Observatory test data in 2022 shows that when lifepo4 battery packs are used to supply power to meteorological equipment (load power 800W) with an ambient temperature of -25°C, voltage fluctuation is ±2% (±8% for lead-acid batteries), and the capacity retention rate is 88% (35% for lead-acid batteries). But in continuous use at below -30°C, its charging efficiency will be reduced to 70%, and it must rely on external insulation measures (e.g., insulation layers or temperature control chambers).
In terms of high-temperature resistance, lifepo4’s 60°C cycle life is 4,000 times (capacity retention rate ≥80%), which is far greater than the 200 times of lead-acid batteries. It complies with the UL 1973 certification standard, its thermal runaway trigger temperature up to 270°C (150°C for ternary lithium batteries) and thermal diffusion probability of less than 0.001%. For instance, in a certain photovoltaic energy storage project in the Australian desert area, the lifepo4 battery was continuously operating at 55°C for 180 days, and the capacity fading rate was only 6% (while lead-acid batteries experienced an attenuation of 47% within the same period of time). But when the temperature is above 60°C for a long time, the decomposition rate of the electrolyte will increase (0.1% per day), and an active cooling system (liquid cooling or air cooling) must be adopted to keep the temperature difference within ±3°C.
In terms of temperature control technology, lifepo4 batteries with smart BMS can broaden the operating temperature range to -30°C to 65°C. For instance, BYD’s Blade Battery, through the application of pulse heating technology (with a frequency of 100 Hz), has improved its charging efficiency from 65% to 85% at -20°C and reduced the charging time by 30%. TUV Rheinland tests in 2023 showed that the lifepo4 battery pack integrated with a liquid cooling system had a cell temperature difference of only 1.5°C when under a high load of 45°C (1C rate) (up to 12°C without a temperature control system), and its cycle life was extended by 18%.
Empirical data prove that the temperature adaptability of lifepo4 has covered 95% of the world population distribution area. According to the statistics of the International Energy Agency, its failure rates in Northern Europe (with an average annual temperature of 5°C) and the equatorial region (with an average annual temperature of 28°C) are 0.8 times per thousand units and 1.2 times per thousand units respectively, which are much lower than the 4.5 times and 6.3 times of lead-acid batteries. For instance, a photovoltaic power station in Saudi Arabia used lifepo4 batteries (average daily temperature 40°C), and the capacity retention rate was still 82% after five years, while the scrapping rate of the lead-acid battery packs had reached 100% within the same period.