The lithium-ion battery revolution
Finally, and this is one of its main advantages, Naval Group's new ocean-going submarine is equipped with a new generation of lithium-ion batteries that are revolutionizing the operation of non-nuclear-powered vessels.
Submariners believe that in combat, the robustness and performance of the new batteries will provide an undeniable operational advantage and increased survivability compared to fuel cells, whose performance in the event of depth charges remains unknown, as the situation has never arisen. Furthermore, submarine mobility has become a vital issue in the face of the proliferation of anti-submarine warfare (ASW) capabilities. This leads a former French submarine commander to declare that "the old-fashioned warfare, where submarines behaved like drifting mines, is over."
Far safer than the older lead-acid batteries found in most conventional submarines, they have a 40% longer lifespan and, moreover, offer a significantly higher energy density. Thus, the submarine, capable of reaching speeds of 20 knots submerged, can, at any time, access maximum power for its tactical maneuvers, particularly in dangerous situations, such as when it needs to evade an enemy torpedo or escape an anti-submarine warfare helicopter. This capability is crucial for the survival of the vessel and its crew.
Li-ion battery technology allows the vessel, depending on the mission profile, to remain submerged for up to 14 days. On paper, this is slightly less than some air-independent propulsion (AIP) systems sold by competitors, such as German fuel cells, which, according to their manufacturer, can offer up to three weeks of underwater autonomy. However, this duration is achieved by navigating at very low speeds, just a few knots, when the submarine isn't simply drifting, whereas the Li-ion solution, for example, offers, according to Naval Group, twice the evasive endurance. In short, according to the French manufacturer, the Blacksword Barracuda benefits from strategic mobility and a long-range projection capability that its adversaries lack. This was one of the key arguments that swayed the Dutch bidder, where the choice of the French offer was not initially a given. However, when the Dutch compared the performances, they were convinced by the Li-ion solution.
These batteries also offer other crucial advantages, such as their ability to be used regardless of their charge level and their charging flexibility. Whenever possible, the submarine, which regularly returns to the surface to report its position to headquarters, gather intelligence, and receive orders, can, at periscope depth, deploy its snorkel to draw in fresh air and immediately start its diesel engines to begin recharging its batteries. For this purpose, the Blacksword Barracuda is equipped with a dry air tube system, which allows the engines to start immediately, whereas older tubes were filled with water and had to be drained before use, a process that could take around twenty minutes. The Naval Group submarine is also equipped with two large MTU diesel engines to accelerate the recharging process. A few dozen minutes are enough to recover part of the charge and, if the batteries are totally depleted, it takes less than a night to recharge them to 100%.
