So much power to go faster, and further, in full-electric mode. Safe lithium batteries that don’t catch fire and miniaturised components. These are the reasons for the success of the e-Motion hybrid system
by Niccolò Volpati
e-Motion features a high-powered system that is very efficient and is designed to ensure electricity is used more often, and diesel engines less often. The e-Motion hybrid technology is genuinely an alternative to traditional propulsion systems. And it is no coincidence that more and more yards are using it, and amongst new clients, there are catamaran producers, both sailing and power.
What are the components in a system of this type and, above all, how is it different from other hybrid systems? Diesel engines, electric motors, and variable speed generators are the essential components. That way, there are at least three ways to recharge the batteries. The advantage is that you need very little time to do so. Essentially a yacht that uses the e-Motion hybrid system, even when at anchor, with a half-hour recharge in the morning and another in the evening will have at least twelve hours of range, traveling in complete silence because there won’t be any need at all to turn the generators on.
THANKS TO THE WAY ITS COMPONENTS HAVE BEEN MINIATURISED,
THE E-MOTION HYBRID SYSTEM IS ALSO SUITABLE FOR SMALL
AND MEDIUM-SIZED BOATS.
«We have opted for high-power electric engines», says Michele Maggi, «both to deliver speed when underway in full electric mode, and also to have an extra power source to recharge the batteries». The difference is that the boats that use this hybrid system can do between 22 and 28 nautical miles, according to size and displacement, using only electric power. The electric motor with a clutch has a 240-kW rating, to which a further 180 can be added from the variable speed generator. The electric motor can also be used as a generator and so it is easy to work out why the batteries recharge so fast. The other essential element in this system is the batteries themselves.
All this power means having a greater range in full-electric mode, to go faster and charge the batteries more quickly.
e-Motion has signed an agreement for battery construction with CATL, the Chinese firm that holds 35% of the global market of lithium accumulators. This has enabled it to use the LFP cells (which have been developed only very recently) and the firm is the only one to do so in the yachting world. These cells are safer because, thanks to the chemicals used in their components, in the event of a thermal runaway, instead of exploding, they increase in temperature and, developing O2 in the chemical reaction, they also develop a very limited and short-lasting flame. The battery pack is built to pass the class register tests that guarantee confinement and the impossibility of causing thermal runaway to other cells of the same pack and the materials together with the cooling guarantee the containment of the phenomenon inside the pack. Furthermore, they are very quick to recharge. The best batteries that Tesla cars use need around ninety minutes for a complete cycle, while batteries with LFP cells and the power that comes from the engines and the generator, only use thirty.
THE LITHIUM BATTERIES ARE BUILT IN-HOUSE THANKS TO A DEAL WITH CATL, AND THEY USE LFP CELLS.
The company has created two battery packs, a 26 kW one and a 39 kW one, to be paired with two different diesel engine outputs: the 440 horsepower from the Yanmars, or the 800 hp developed by the MAN motors. The two systems are on a different scale to fit with the size and power requirements of particular yachts. The battery packs are of the same size as a generator which is normally fitted into an engine room to supply the onboard equipment. It is an option dictated by the need to fulfill the requirements of replacing engines. Indeed, as well as being installed on new boats with engine rooms that have been specially designed, it can also be used in substituting traditional power units.e-Motion has also introduced a series of safety features in addition to the “chemical” factor, which means any battery overheating can be contained.
After having won orders from Sanlorenzo and other producers of large yachts, the system is now to be found amongst Aquila powered-catamarans and also sailing multi-hulls.
The batteries are built from 17-cell modules, with six modules grouped. All that is enclosed in a covering that is fire and impact resistant. The certification tests mean they are exposed to uncovered flames for 150 seconds and they don’t only not have to catch the light but have to not heat up to over 80 °C. This kind of construction guarantees that the batteries are safe. It is no secret that lithium and water do not mix. Indeed, what happens is that the lithium catches the light and, most importantly, cannot be put out. There are no extinguishers, foam, or water cannons that can put out a lithium battery once it has caught fire. And it is easy to imagine that the flames would spread from the battery to the whole boat. The company has worked on miniaturisation.
The batteries, both because of the materials that they use and the way they are constructed are guaranteed and certified as fire resistant and so are safer than normal lithium batteries.
A lot of power and significant energy do not necessarily entail requiring a huge amount of space. There has been a focus on reducing size, to meet the needs of boats where the engine room is not very large. It is no surprise that the e-Motion hybrid system has also been warmly greeted by owners of catamarans, both sailing, and power. The smallest multi-hull that it has been used on is a 15-meter catamaran. And keeping downsize does not just involve power systems, but also control panels, which have been designed precisely so as not to take up too much space on the dashboard.
The Power Management System at the heart of things is similar in size to the black box for a plotter. Finally, customisation has been a reason for its success. The management software has been personalised on two levels. The first customisation involves imposing parameters for the inverters which are used to make all of the equipment in the hybrid system interact. The second is the way that control software is personalised in a way that takes into account the boat’s characteristics. The software works on the engine power curves, on those of the electric motor, on the fluid dynamics of the hull, and even on the propellers. And having customisable software is a further advantage in keeping both new and used boat buyers happy when they decide to move on to a hybrid system.
(e-Motion Hybrid System, High Power Hybrid – Barchemagazine.com – November 2022)
