CATL claims 500 watt hours per kilogram for aircraft and 350 for cars under its condensed battery brand, and no outside lab has checked either number

What CATL announced in 2023

Energy density measures how much energy a battery holds for each kilogram it weighs. A higher number means a lighter battery, or a longer range. In April 2023, CATL, a Chinese battery maker, announced a battery it branded the condensed battery, aimed first at electric aircraft, claiming an energy density of up to 500 watt hours per kilogram. Condensed matter is a term borrowed from physics, the branch covering solids and liquids. CATL is the only one of the 5 sources that uses the term as a product name, and has not disclosed what material sits inside the cell.

What an outside scientist calls it

A week after the announcement, an independent assessment from the Helmholtz Institute Ulm for Electrochemical Energy Storage, a public research institute in Germany, gave the technology a different name.

The Condensed Battery from CATL is a so-called Almost Solid State Battery, ASSB.

Maximilian Fichtner, battery researcher at the Helmholtz Institute Ulm for Electrochemical Energy Storage, independent of CATL. Source 3.

An Almost Solid State Battery, the term the institute uses, differs from a true solid state battery, a design with no liquid or gel inside the cell. An anode is the electrode a cell charges into. The institute names 4 chemistries it considers possible without confirming any, a lithium metal battery, a silicon anode design, an anode less design, and a lithium sulphur design. CATL has not said which, if any, is correct.

A 2023 promise not kept on time

In 2023, CATL said an automotive version of the condensed battery would enter mass production that same year. No source reports that happening. The next dated statement CATL made about a car focused condensed battery came 3 years later, in April 2026, describing the technology only as unveiled, not yet shipping in a named car.

The number attached to the condensed battery brand moved from 500 to 350, but the 2 figures describe 2 different products, an aircraft cell and a car cell, not the same cell measured twice.

A different battery for cars, introduced in 2026

At an event CATL calls Tech Day, the company unveiled the Qilin Condensed Battery, its first condensed design for passenger cars, stating a cell energy density of 350 watt hours per kilogram. A cathode is the electrode opposite the anode, releasing charge while a battery is in use. CATL says a new high nickel cathode combined with a silicon carbon anode adds 50 watt hours per kilogram, and a titanium alloy case, the metal shell around the cell, adds a further 20, while cutting case thickness by 60% and case weight by 30%.

CATL states the design could give a sedan a range of 1,500 kilometers, and a large sport utility vehicle more than 1,000 kilometers, with the finished pack under 650 kilograms. No outside test confirms any of these figures.

The only named aviation user is not an independent customer

CATL also states that 500 watt hour per kilogram aviation grade cells completed flight validation in 2026 on a 4 tonne aircraft, with more validation underway on aircraft above 8 tonnes. The aircraft belongs to AutoFlight, a maker of electric vertical take off and landing aircraft that CATL has itself invested in, so the company flying it has no independent reason to report a failure.

No outside test yet

Across all 5 sources, 2 newsroom statements from CATL, 1 assessment from an independent research institute and 2 pieces of independent news coverage, not 1 reports an outside laboratory measuring the 500 or the 350 figure. That absence, not a failed test, is the finding.