Following in the footsteps of the Japanese and South Korean navies, the Indian Navy has issued a RFI seeking details of Li-ion batteries. These batteries will be fitted in all the future submarines in the Indian Navy which are being designed to use this technology.
Lithium-ion battery development is at an advanced stage with all leading global submarine manufacturers and one could guesstimate that by the end of this decade, all modern SSKs will be powered by Li-ion batteries.
“Indian submarines still do not have Air-independent Propulsion (AIP) even on the latest Kalvari class submarines. India’s DRDO is developing an indigenous fuel cell AIP system but fitment on a submarine is yet some distance away,” Indian Navy veteran Commodore Anil Jai Singh tells Financial Express Online.
Also read | Operational air-independent propulsion for Kalvari submarines: A critical technology for underwater stealth
Financial Express Online has been reporting on India’s exploratory visits to the `Lithium Triangle’ nations (Argentina, Bolivia & Chile) to meet its target of having Electric Vehicles by 2030. And it was for this reason in 2019, the government has formed `KABIL’ consortium which has three state-owned companies: National Aluminum Company (NALCO), Hindustan Copper (HCL) and Mineral Exploration Corp Ltd., (MECL).
The Purpose of this consortium
It has been set up to help in the process of acquiring this most strategic mineral globally. This mineral is required not only for the EVs but is used in other sectors including space launchers, solar panels, mobile phones and laptops and hi-tech military platforms including submarines for the Indian Navy. KABIL will help in processing the mineral once acquired from any of the three countries in South America.
Last year, President Ram Nath Kovind had visited two out of the three ‘Lithium Triangle’ nations and the focus of talks was also on joint manufacturing and facilitating the process of acquiring the rare metal. And, the former President of Argentina Mauricio Marci, had also visited India.
Also read | India looks at South America’s Lithium Triangle to fulfil its increasing clean energy demands
Today, since there is a huge demand for the Li-on batteries and cells due to their high energy density, these are imported 100 per cent. With the ongoing standoff between India and China, the focus has now shifted on setting up R&D and Technology Development Facilities, as the government plans to manufacture the batteries and cells here locally.
While India and Bolivia are in talks about having a joint manufacturing base for the batteries, both Chile and Argentina are in talks about exploration and exports of Lithium.
Submarines of Japan & South Korea
“In March 2020, the JMSDF (Japanese Maritime Self Defence Force) became the first navy in the world to operationalise lithium-ion battery technology on submarines onboard its newest submarine, JS Ouryo, the 11th of the Soryu class submarines commissioned in March 2020. Lithium-ion batteries will also power the 12th and last of the Soryu class and the forthcoming Tiagei class, the first of which was launched in November 2020. Many more navies are expected to follow suit with the South Korean Navy’s new KSS-III submarines, currently under construction also being fitted with this technology,” says Indian Navy veteran Commodore Anil Jai Singh.
According to the former submariner, “The South Koreans are planning to go a step further than the Japanese. While the Japanese have done away with their Stirling engine based Air-independent Propulsion (AIP) system onboard the Ouryo and its successor, the South Koreans are planning to reconfigure their fuel cell AIP system to operate in conjunction with the lithium-ion batteries on board. This will greatly enhance both, the speed and the endurance of diesel-electric submarines (SSK). Most other submarine manufacturers are expected to follow suit with each of them in various stages of developing Li-ion battery systems for their respective designs.”
Also read | Air-Independent Propulsion for Kalvari Class Submarines: Urgent need for the stealth technology
Use of Lithium Batteries & how will it help
According to Commodore Singh, “Li-ion batteries are already being used to power practice torpedoes and unmanned underwater vehicles but there had been a hesitation to incorporate these onboard submarines because of lingering safety concerns. The exploding Samsung -7 Note mobile telephones and the frequent fires on board the Boeing 787 aircraft were both attributed to lithium-ion batteries.”
This breakthrough technology which has begun replacing the traditional lead-acid batteries in use for over one hundred years on submarines greatly reduces the constraints on underwater speed and endurance that limits the options available for their deployment. Lead-acid batteries, because of their high discharge rates required to be charged frequently and even the most conservative operational profile underwater would still require them to be charged at least once in 48-72 hours.
“Doing top speed underwater would discharge them in about a couple of hours. Charging of batteries requires a submarine to operate its diesel generators which then charge the batteries. The diesel generators need fresh air for their operation. Hence the submarine has to expose its ‘snorkel’ mast to take in fresh air and risks detection by the enemy. This complicates the Commanding Officer’s options to attack or evade the enemy in hostile waters. Improvements in lead-acid battery technology over the years has mitigated this to some extent with the endeavour being to minimise the ‘indiscretion rate’ which is the percentage of the time a submarine is exposed in a 24-hour cycle,” he explains to Financial Express Online.
“The introduction of AIP systems which allows a submarine at economical speed to remain underwater for up to a fortnight without charging batteries has reduced indiscretion rates to a negligible value but has not appreciably enhanced the operational profile at higher speeds. Lithium-ion batteries, with their higher energy and longer lifecycle are set to change this by improving the endurance at higher speeds thus providing the submarine commander with a wider range of tactical options and will also facilitate the integration of the submarine into a network-centric force deployment over a larger area of the ocean,” he adds.
In conclusion, he says, “One of the main concerns which inhibited their deployment of submarines was the hazards of thermal runaway, fire and explosion but as development has progressed these have been addressed and the operational deployment of these on submarines is reassuring.”