AQUBE Comes Aboard: What the DLR Research Vessel Order Means for Your Next Hybrid Refit

Crew Voices 23 August 2026 Updated 23 August 2026

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Lloyd Werft's Bremerhaven yard has selected the AQUBE liquid-cooled battery platform to power a new seagoing technology platform for the German Aerospace Center (DLR), Germany's national research centre for aeronautics, space, energy and transport ¹. Delivery is set for 2027.

The vessel is 48 metres long with an 11.5 metre beam. It will carry up to 20 researchers on multi-day voyages into the North and Baltic Seas, testing hydrogen, hybrid and fully electric propulsion setups along the way ¹. Anyone specifying a refit or new build in the next few years should read this carefully. This is a real spec sheet, and it tells you something about the systems you'll be expected to run and the training your engine room will need before that gear shows up.

The Battery Backs Up Your Genset, It Doesnt Replace It

AQUBE isn't a standalone propulsion source. It sits inside a hybrid architecture. It takes peak loads off the gensets rather than replacing them.

That's the same logic behind the retrofit AYK Energy delivered on the Ro-Pax ferry Aurora Botnia. That job lifted installed battery capacity from 2.2 MWh to 12.6 MWh, more than fivefold. The battery bank was fitted alongside the ferry's existing dual-fuel engines, not in place of them ².

Understand this before you write a single spec line. The diesel-electric plant stays, sized for cruise load. The battery bank absorbs the spikes.

AQUBE's headline figure is a 2C peak, 1.5C continuous discharge rating ¹. In plain terms, the pack can dump its full stored capacity in as little as 30 minutes ¹. On a working vessel, that's the difference between the genset carrying a flat, predictable load and the battery absorbing manoeuvring surges or a bow thruster spike. For DLR's platform, the manufacturer frames this explicitly as the power needed to manoeuvre the ship through rough North Sea conditions and support onboard experimental loads ¹.

Liquid Cooling Means New Rounds

The other difference from anything you've likely managed before is the cooling. AQUBE circulates liquid directly around the modules rather than relying on air cooling ¹. That's a new maintenance job, not a variation on an old one. Coolant loops, pumps and heat exchangers now sit on your battery room walk-round, alongside your genset jacket water routine, not instead of it.

Chemistry matters too. AQUBE uses Lithium Iron Phosphate (LFP) cells ¹, the same chemistry AYK used in the Aurora Botnia retrofit, where the manufacturer describes LFP as inherently more fire-resistant and thermally stable than cobalt-based alternatives ². Ask Lehmann Marine directly whether that same framing holds for AQUBE's own pack. Don't assume it. The chemistry class is confirmed, and it should shape your fire suppression and containment planning at the design stage, not as a retrofit afterthought.

If you're budgeting a refit, add coolant quality and flow monitoring to your daily rounds now. There's no genset equivalent to fall back on.

Your BMS Data Needs to Be Read Like an Engine Room Log

Genset management runs on hours, oil samples and known wear curves. A lithium battery bank runs on something else entirely: state-of-charge windows, cell balancing, thermal trending, cycle counting. Most of it runs continuous, not scheduled. Expect your battery management system (BMS) data to become part of your daily rounds, checked with the same seriousness as your engine room log.

Thermal runaway in a lithium pack doesn't announce itself the way a genset bearing failure does. There's no rising vibration signature to catch on a walk-round three days out. The failure mode is a cell venting flammable gas before it ever gets hot enough to see on a standard thermal camera. That's why the response drilled into crews on dedicated lithium-ion battery safety courses starts with gas detection, not fire suppression: isolating ventilation, confirming which suppression medium is actually rated for a battery fire (most engine room CO2 systems aren't), and knowing the shutdown sequence for a cell group before the fault propagates to the next one ³.

That's a different drill to anything in a standard engine-room ticket. Train it specifically. Don't rely on general electrical safety awareness to cover the gap.

Your SMS Is Probably Behind the Hardware

The certification pathway hasn't caught up with the hardware rolling onto yards, and most engineering departments are behind as a result. STCW's familiarisation requirements (Section A-I/14, often referred to as Regulation I/14.5) already require companies to make sure seafarers know the ship's arrangements and equipment before they're expected to work on them ³.

In practice, that means your SMS needs to spell out battery response protocols the way it already does genset shutdown, not leave the battery room covered by a generic electrical hazards page written before the pack went in. If your fire plan, muster procedures and crew certification records were all written before batteries were fitted, that's the gap to close. Close it before the system arrives, not after commissioning, when a surveyor asks to see it in writing.

The Retrofit Timeline Might Be Shorter Than You Think

Retrofits like Aurora Botnia's aren't a one-off. AYK Energy describes the project as the world's largest marine battery retrofit to date ². It's a useful reference point if you're arguing for a phased retrofit window rather than a long yard period. The work was carried out during normal operation and finalised at a repair yard, delivered on time and on budget, without gutting the vessel's diesel-electric plant ².

If your board is asking whether a hybrid retrofit means months alongside, that's the number to bring to the meeting.

What to Ask Your Vendor

Ask your battery vendor for the same detail Lloyd Werft got from AQUBE:

Peak and continuous discharge rating
Cooling architecture
Cell chemistry
How the pack is meant to sit alongside your existing plant rather than replace it ¹

Those answers cover most of what your classification society will ask anyway. They're also the same details that will tell you whether your current SMS, fire plan and crew tickets are actually ready for what's coming aboard, or whether they still describe the ship you had before the battery went in.