In 2020, a Request for Information (RFI) of the Indian Navy for the development of a ‘high-capacity’ lithium-ion battery system to be retrofitted on an existing in-service submarine was initiated for Indian vendors to replace older lead-acid batteries for underwater propulsion.

Navy has now selected the vendor and after proof of concept and the technology has now given go-ahead for the development of compact lithium-ion battery pack that will be replacing older lead-acid batteries that will be first equipped on a Russian supplied Kilo-class submarines for user trials purposes and if found satisfactory will be later adapted on the other Kilo-class submarines and later also on the Kalvari class submarines.

Lithium-ion batteries are lighter than lead-acid batteries and also generate less heat due to which underwater endurance of the submarines will be three-time more than the existing 48-72 hour endurance which are provided by the lead-acid batteries. lithium-ion batteries can also provide large output on demand, allowing the boat to dash mush faster while dived and don’t require regular maintenance or water top-ups.

The cost of lithium-ion batteries remains high due to which it is still not widely adopted. has been told each lithium-ion battery pack will make up 25-30% cost of the submarine and, adopting it on older submarines will make it 50-60% of the submarine’s acquired cost.

Japan and South Korea are only two countries that have adopted air-independent propulsion’ (AIP) and Lithium-ion batteries widely on their conventional attack submarines and if implemented successfully on Indian Kilo-class submarines, India will be the first country to have adopted the next-gen battery technology on the older conventional attack submarines.

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