Xiaomi SU7 Max Passes High-Temperature, Fully Charged NMC Battery Nail Penetration Test

On April 5, Xiaomi announced that its SU7 Max variant successfully passed a high-temperature, fully charged needle penetration test on its ternary lithium-ion battery. The test was conducted under more stringent conditions than the current national standard—specifically at a battery temperature of 55°C and 100% state of charge, compared to the standard requirement of 22±5°C and ≥95% state of charge. Using the industry-recognized needle penetration method to trigger thermal runaway, the test directly damaged the structure of a single cell, causing an instantaneous short circuit and localized high temperatures. During the test, although one cell experienced thermal runaway, it did not propagate to adjacent cells; the battery pack neither caught fire nor exploded. The vehicle’s internal and external alarm systems, cloud-based alerts, and door-unlocking functions all activated normally, and no visible smoke was observed inside the cabin, marking a successful completion of the test.