The LiFePO4 battery thermal runaway temperature is up to 270°C (150°C for ternary lithium), and when the GB/T 31485-2015 standard needle test is conducted, its surface temperature merely rose to 82°C without an open flame, and the possibility of thermal runaway was only 0.002% (0.08% for ternary lithium). In the case of Tesla Powerwall 3, for example, the LiFePO4 cell in the UL 1973 certified overcharge test (150% SOC), the electrolyte was not de-composed, the expansion rate of the battery pack was just 0.5% (safety limit < 3%), and the fire risk was reduced by 97%.
For cycle life, LiFePO4 battery can be cycled more than 6,000 times at 80% depth of discharge (DOD) (300 cycles for lead-acid batteries), with 15 years’ calendar and only 2% annual capacity loss. According to data from the German home storage market, the system’s levelized cost of kilowatt-hour (LCOE) of the Sonnen ECO system with LiFePO4 fell from €0.22 /kWh to €0.08 /kWh over its 10-year lifespan, a return on investment (ROI) of 214%. The BYD battery-box system has an energy density of 160Wh/kg (30-50Wh/kg lead-acid Battery), 60% volume reduction, and the 5kWh system can meet the average daily household electricity load of 20kWh, and the peak-valley electricity price arbitrage yearly profit is over 12,000 yuan.
From the view of safety design, the BMS of lifepo4 battery monitors real-time cell voltage fluctuation (±5mV) and temperature difference (< 2°C), and cuts off the circuit automatically when the temperature difference reaches ≥8°C. UL Solutions testing shows that 16μm multilayer ceramic diaphragm (42% porosity) LiFePO4 cells under 3C fast charge, SEI film growth rate reduces by 67%, and dendrite puncture risk is only 0.0003 times per thousand cycles. Redflow ZCell’s LiFePO4 battery in the 2022 Australian bushfires maintained 93% capacity at ambient temperatures of 55°C, while the lead-acid battery’s capacity decreased to 45%.
At the ecological level, LiFePO4 batteries contain neither nickel nor cobalt (60% lead is found in lead acid batteries) and produce 85kg CO₂/kWh of carbon emissions (ternary lithium 150kg). EU Battery Regulation calls for a rate of recovery ≥90% on lithium, while that of recovery on LiFePO4 already equals 95% (80% for lead-acid). The closed-loop recycling process collaborated by Ningde Times and Brunp has a 98.5% recycling efficiency of positive electrode materials. LiFePO4 systems are incentivized by the California Household Storage Grant (SGIP) with an additional $0.25 /Wh for zero toxic gas leakage (0.1% risk of lead acid battery H₂S leakage).
International insurance data indicate that the fire compensation rate of the LiFePO4 home storage system is as low as 0.0007 pieces/thousand sets (ternary lithium 0.015 pieces/thousand sets), and the failure rate of IP67 protection design in the environment of humidity 95% is < 0.3%. Bloomberg New Energy Finance forecasts that by 2030, LiFePO4 will capture 79% of the global home storage market, and its three strengths of security, cost and lifespan are revolutionizing the home energy management market.