CATL aviation battery passes two-cell thermal runaway test for eVTOLs
CATL says its 350 Wh/kg aviation battery is the world's first prismatic-cell system to survive simultaneous two-cell thermal propagation triggers, clearing a key hurdle for eVTOL use.
- 350 Wh/kg
- 2,000 aircraft
- 242.7 GWh
- 39.9%
What Happened
CATL, the biggest maker of power batteries, said its passenger-eVTOL aviation pack cleared a verification test with no thermal-runaway spread when two neighbouring cells were set off at once. Testing covered several spots in the pack, the middle and the corners among them, and CATL said no other prismatic-cell aviation pack at a 350 Wh/kg energy density had cleared the test before. Appointed observers from China's Civil Aviation Administration oversaw the build, inspection and testing, a step toward letting eVTOL aircraft meet civil-aviation safety rules.
High-energy-density batteries carry an inherent danger in thermal runaway propagation, and that risk only sharpens in an aviation context. Industry practice has long been to confirm no propagation follows a single triggered cell — CATL raised the bar by setting off two adjacent cells at once, a tougher and more realistic stress test. Clearing it, the company argues, shows the pack can survive a failure mode closer to what could actually happen in service.
350 Wh/kgWh/kg
World's first prismatic-cell aviation battery to pass a two-cell thermal propagation test.
CATL agrees to take a strategic stake in Shanghai-based Autoflight, its sole investor putting in hundreds of millions of dollars - CATL's first eVTOL investment made public.
The two show a floating vertiport, essentially a battery-powered boat carrying an eVTOL take-off and landing pad plus solar storage and charging, which they call the eVTOL sector's first combined sea-and-air setup.
CATL's aviation pack passes the two-cell thermal-propagation test and is declared ready for volume production.
According to CATL, the battery system has cleared the bar for mass production and is slated to debut in passenger eVTOLs built by Autoflight, a startup the battery maker backs financially. Founded in 2017, Autoflight ranks among China's earliest eVTOL entrants and had racked up 2,000 aircraft in cumulative commercial orders as of November 2025. From its base in Ningde, Fujian province, CATL is angling to push its technology well past EVs, into electric vessels and aviation as well.
CATL fitted 242.7 GWh of EV batteries worldwide in the first half of 2026, a 25.3% year-on-year gain that gave it a 39.9% share, on figures from South Korean research house SNE Research. Its aviation-battery drive is part of a wider move beyond ordinary EV use, following the floating vertiport and the Autoflight stake as earlier steps in the same direction.
Why this matters
Thermal runaway is one of the biggest risks in high-energy-density batteries, and aviation is especially sensitive to it. Passing a test that triggers two adjacent cells at once — far stricter than the industry's usual single-cell check — brings the battery closer to meeting civil aviation safety standards. That makes mass production for Autoflight's passenger eVTOLs more credible and could help push electric vertical takeoff and landing aircraft toward c…
Terms in This Story
- eVTOL
- Electric vertical takeoff and landing aircraft, often used for urban air mobility.
- thermal runaway
- A chain reaction inside a battery cell that causes rapid overheating and can lead to fire or explosion.
- prismatic cell
- A battery cell with a flat, rectangular shape, often used in automotive and aviation packs.
- energy density
- The amount of energy stored per unit of weight (or volume), commonly measured in Wh/kg.
A brief summary; details can be imperfect — always verify against the original source.