Japan launches 12th Soryu-class submarine, second fitted with Litium-Ion batteries

The Toryu during launching. Photo c/o KHI.

Japanese shipbuilder Kawasaki Heavy Industries (KHI) launched the second Soryu-class diesel-electric submarine fitted with lithium-ion batteries for the Japan Maritime Self Defense Force (JMSDF), in ceremonies held in KHI’s yard in Kobe on 6 November 2019.

The submarine was named Toryu (SS-512), meaning “Fighting Dragon”, is also the 12th and most likely the final Soryu-class submarine to be built for the JMSDF. It is also the sixth ship of the class to be built by KHI, as the other six were built by Mitsubishi Heavy Industries (MHI).

The Soryu-class are the first submarines in the world to be equipped with lithium-ion batteries, which is said to store more energy than lead-acid batteries mounted on ten of the submarines of the class.

The Toryu had its keel laid in January 2017, and is expected to enter service with the JMSDF by March 2021.

The Soryu-class submarines are 84 meters long, has a beam of 9.1 meters, and a displacement of 2,950 tons surfaced and 4,100 tons submerged. 

They are armed with six 533mm bow mounted torpedo tubes which employs the Japanese Type 89 heavyweight torpedo and the American UGM-84C Harpoon submarine-launched anti-ship missiles. 

They are powered by two Kawasaki 12V 25/25 diesel generators, four Kawasaki Kockums V4-275R Stirling air-independent propulsion (AIP) engines, in addition to the lead-acid or lithium-ion batteries. This allows the submarine to be propelled to a maximum speed of 12 knots when surfaced and 20 knots when submerged.


[1] Jane’s Defence Weekly
[2] Naval News