[DigitalToday reporter Hyunwoo Choo] China's CATL rechecked lithium iron phosphate (LFP) battery cells it operated for 14 years and found about 85 percent of their initial capacity remained. InsideEVs reported on Sept. 26 that the cells were recovered from the Zhangbei project, the world's first large-scale lithium-ion battery energy storage project.

The Zhangbei project's 63 megawatt-hour battery system started operating in 2011 and ran through June 2025. It supplied eco-friendly power during the 2022 Winter Olympics. Despite repeated charging and discharging for about 14 years, all cells continued to work and none were replaced.

After the project ended, CATL sent more than 50 prismatic LFP cells to a lab to check for damage and remaining life. It assessed that the 14-year-old cells could be used for about 10 more years in small or auxiliary energy storage systems and could handle about 1,000 charge-discharge cycles.

There were interim inspection results as well. CATL took out some samples and tested them nine years after start-up, confirming at the time that the cells were in a condition to withstand 6,000 more cycles. The latest assessment confirmed the final condition after the end of actual operation.

The battery's internal structure also remained relatively stable. The anode and cathode stayed aligned and lithium insertion was satisfactory. No clear signs of aging were found in the graphite.

CATL viewed these results as due to a safety-focused design and characteristics of LFP. LFP cells have lower energy density than nickel-manganese-cobalt (NMC) types, but can better withstand repeated use and harsh operating conditions. Lower production costs are also expanding their use across electric vehicles and energy storage systems.