While Li-ion batteries offered similar endurance to an AIP system combined with lead-acid batteries at low speeds, their advantage was found in longer endurance at higher speeds (e.g. during an approach or evasion) thanks to their higher capacity.
Furthermore, Li-ion batteries can be recharged at sea by snorkeling.
They also have a shorter indiscretion time due to a high charge current, whereas lead-acid batteries take a long time to restore their electrical capacity. Additionally, Li-ion batteries have a long life, are maintenance-free, enjoy simple operation and result in a simpler power structure.
That’s why they choose Li-ion batteries.