Floating measuring station was launched in the Arctic Ocean

In collaboration with a study group at Aarhus University, we have developed a battery pack for a floating measuring station that can operate below freezing and at a depth of 300 meters.

The measuring station was launched in the Arctic Ocean in August and the project has been a success.

"We have just returned from Northeast Greenland with a lot of valuable learning and data in our luggage. The trip went as planned and our measuring instrument was a success. However, we never managed to test for so long that the batteries were completely drained - which is positive. We had the instrument out for a couple of days, both time and money are saved by this instrument compared to the competitors and the Arctic scientists we went with, use it to assess the melting of the ice sheet and how it mixes with the seawater, which can affect the Gulf Stream the global environment. Thank you very much for your help with batteries".

-          Lucas Sandby, Aarhus University College of Engineerin

Tough requirements for a sustainable solution

The study group's project was to develop a floating measuring station for use in the Arctic Ocean. To perform the measurements, the measuring station must dive below the surface - sometimes up to 300 meters. Also special for the task was that the equipment had to be designed to operate below freezing for a minimum of 3 months.

All technology, including the batteries, had to be assembled in a cylinder with a diameter of approx. 250 mm and a height of 300 mm. The total weight also played a role, as the equipment had to be able to dive - and return to the surfac

ACTEC chose, in collaboration with the study group, to produce a total of 4 battery packs for the measuring station. Each battery pack consists of 10 HHR450A battery cells. The individual battery packs were specially welded in the shape of an arc and placed individually around the motor of the measuring station. The battery packs were then connected in series and in parallel, so that the total battery matched the application's requirements for 400Wh and 24V DC.

NiMH over Lithium

NiMH configurations, as above, are a good match for applications that are primarily used in cold - or fluctuating weather conditions.

This is due to the fact that NiMH loses significantly less capacity than e.g., Lithium-ion. This can in some cases already be experienced when the batteries are used in temperatures below 10°C.

NiMH batteries are a lot heavier than Lithium-ion batteries and for this task, it was actually an advantage in that the extra weight ‘assisted’ with reducing buoyancy when the equipment dives.