Lehman Marine — a Sunlight Group company with marine engineering operations in Germany — has secured its first commercial order for AQUBE, a newly developed liquid-cooled battery energy storage system, after shipbuilder Lloyd Werft in Bremerhaven awarded it a contract for a research vessel being built for Germany's national aerospace and transport research centre, the German Aerospace Center (DLR).

The vessel — a 48-metre-long, 11.5-metre-wide seagoing technology platform — is scheduled for delivery in 2027 and will be used by DLR to test next-generation climate-neutral propulsion technologies, including hydrogen, hybrid and fully electric systems, under real-world maritime conditions in the North and Baltic Seas. The vessel will accommodate up to 20 researchers and industry partners and is designed to conduct multi-day test voyages.

The AQUBE system is described by Lehman Marine as a high-power energy storage platform built around three key technical features. The battery is rated at 2C peak discharge performance — meaning it can discharge its full capacity within 30 minutes — with a continuous discharge rate of 1.5C. The system uses a liquid-cooling architecture, in which fluid is circulated directly around the battery modules to regulate operating temperatures, in contrast to conventional air-cooled designs. The chemistry used is lithium iron phosphate (LFP), which the company says offers thermal stability, is free of cobalt and is non-toxic.

Lehman Marine explained that by pairing its German marine engineering operations with Sunlight Group's manufacturing and R&D facilities in Xanthi, Greece, this allows it to offer European shipbuilders a localised supply chain.

Matthias Schubert, Head of Sales and Marketing, commented: "Building on the success of our air-cooled CUBE platform and the proven liquid-cooling heritage of COBRA, AQUBE takes our technology to the next level for demanding marine applications. Securing our first AQUBE contract for a national floating lab of this calibre is a major validation. It proves that our battery architecture is ready to power not just research vessels, but the broader commercial fleet — from ferries and offshore vessels to cargo ships and tankers."

The DLR vessel is intended to bridge the gap between land-based laboratory testing and open-water trials, providing a testbed for propulsion technologies that shipping companies and researchers are exploring as the industry faces pressure to reduce carbon emissions. Shipping is estimated to carry over 80% of world trade by volume.