The Dawn of a New Age in Naval Submarine Propulsion
On Thursday 5 th March 2020 the Japanese Maritime Self-Defense Force (JMSDF) commissioned the 11 th Soryu-class diesel-electric attack submarine (SSK), the JS Oryu (SS-511). The JS Oryu is the world’s first operational naval attack submarine to be equipped with lithium-ion (LIB) main batteries, replacing the lead acid (LAB) main batteries and air independent propulsion (AIP) systems fitted to earlier Soryu-class submarines. A second Soryu-class submarine equipped with LIB main batteries, the JS Toryu , was launched in November 2019 and is expected to enter service in March 2021. There is very little published technical detail about the JS Oryu’s LIB main batteries, but it is understood that they have approximately double the capacity of the earlier Soryu-class LAB main batteries. This would give JS Oryu about twice the submerged patrol endurance (battery-only), and around three times the endurance when running submerged at full speed. Notwithstanding the lack o