The Oryu is the eleventh submarine based on the Soryu’s design. Soryu-class vessels, which started being built in 2005, are among the largest diesel-electric submarines in the world.

But the Oryu is a vastly updated version of the Soryu, the biggest change being the replacement of lead-acid batteries with lithium-ion ones. Mitsubishi Heavy tapped GS Yuasa to supply the high-performance batteries, which store about double the power.

Submarine batteries are recharged by the energy generated by Oryu’s diesel engines. The vessel switches to batteries during operations and actual combat in order to silence the engines and become harder to detect. The lithium-ion batteries radically extend the sub’s range and time it can spend underwater.

Source: Japan’s silent submarines extend range with new batteries – Nikkei Asian Review