CATL says 350 Wh/kg aviation battery passed dual-cell safety test

Two battery cells were triggered at once inside CATL’s aviation pack. Nothing happened to the cells beside them: the company says its 350 Wh/kg prismatic-cell system showed no thermal propagation, even when the triggers were placed in the middle and corners. CATL calls it a world first for an aviation battery system at that energy density.

The test targets one of the hardest problems in electric aircraft. Thermal runaway — a battery failure that can generate intense heat and spread from cell to cell — becomes more consequential as packs store more energy. The usual industry check triggers one cell; CATL’s test triggered two adjacent cells simultaneously, raising the bar for containment.

The work was carried out with production, inspection and testing witnessed by designated representatives of China’s Civil Aviation Administration. That does not mean the aircraft are already flying commercially, but it places the battery work inside the civil-aviation approval path. CATL says the system is ready for mass production.

The first customer is expected to be Autoflight, the Chinese electric vertical takeoff and landing, or eVTOL, company backed by CATL. The two companies signed a strategic investment agreement in August 2024, and Autoflight’s cumulative commercial orders reached 2,000 aircraft as of November last year, according to the report.

So what changes in practice? If CATL’s result holds through later verification and real aircraft operations, it could support passenger aircraft ambitions. CATL’s figures are company claims.