The Indian Navy was looking for a technology that had the potential to improve the performance of its conventional submarines – submarines that do not carry nuclear weapons.
In October the Indian Navy issued a request for information (RFI) looking for the development of a lithium-ion battery system with “high capacity.” The Navy is interested in having the capability to retrofit the technology onto their existing fleet of submarines that use lead-acid batteries. The lithium-ion battery project would have a timeframe of twenty months, beginning with the awarding of the contract, according to the timeline that the Indian Navy established.
The Indian Navy’s submarine fleet modernisation programme primarily emphasises learning from the experiences of other navies, namely those of Japan and South Korea. In March 2020, the Japan Maritime Self-Defense Force was the first to adopt lithium-ion battery technology on its submarines. More precisely, this innovation was implemented on the Soryu-class JS Ouryo submarine. Lithium-ion batteries are going to be installed in all of the submarines of the Soryu class as well as the upcoming Taigei class. South Korea subsequently took the same path. The KSS
Last year it was reported that the Korean shipbuilders would offer the Indian Navy an upgraded version based on the KSS III programme for the P75I submarine building programme. During the Indian competition for the P-75I submarine project, South Korea suggested offering lithium batteries as an alternative to the more conventional lead-acid batteries. According to a spokesman of the South Korean shipbuilding business DSME, the vessel stays submerged for a longer period than was previously thought. He said that the company had replicated the submarine’s battery system and had already completed quality control testing. The company had also announced its plans to integrate this system into the second batch of Dosan Ahn Changho-class submarines. According to reports South Korean lithium batteries are more efficient than traditional lead-acid batteries.
The Chinese also intend to equip their submarines with lithium-ion batteries. In the event of a military attack against Taiwan to seize control of the island that has been autonomous since 1949, the Chinese Navy’s submarine force will be called upon to play a strategic role, especially in repelling any US or NATO fleets that may come to Taiwan’s aid. People’s Liberation Army Navy (PLAN) submarines would be required to identify and assign targets to China’s long-range anti-ship systems, such as the DF- 21D and DF-26, as well as direct attacks by Chinese long-range bombers, in the absence of sufficient aircraft carriers and tanker aircraft to provide a naval and air blockade capable of withstanding Western powers. The Chinese fleet can only rely on its Type 09-III Shang and Shang-G class nuclear submarines for this job, which is not ideal because they are needed for other roles.
Consequently, it must rely on its fleet of conventionally powered submarines. Even the 20th Yuan of the Type 039A class, which is equipped with an AIP (Air Independent Propulsion) system derived from the Stirling system, will be in a perilous position due to AIP’s poor speed. According to the Hong Kong-based publication South China Morning Post (SCMP), the Chinese Navy may soon begin installing lithium-ion batteries instead of the nearly century-old lead-acid batteries in its conventionally-powered submarines.
The same holds true for the submarines of the Indian Navy. Cutting apart the current submarines and installing an AIP module would worsen the dearth of submarines and slow them down. Due to the AIP condition, the schedule for the P75I submarine project was also pushed back. Lithium-ion batteries are simpler to install in the present and future submarines than the cumbersome and slow AIP systems. AIP systems are more suitable for navies with coastal operations than for the Indian Navy, which must operate its submarines for extended periods and as far as the Strait of Malacca, some 2900 kms from India.
In addition to Japan and South Korea, Germany and France have evaluated and studied the benefits of lithium-ion batteries, but they have yet to be implemented in submarines in service.
The Naval Science and Technological Laboratory (NSTL), Visakhapatnam, a Research & Development Laboratory under DRDO, has also developed a High Power Li-ion Battery Technology and possesses the knowledge of numerous technologies relevant to its creation. According to DRDO rules, it is planned to convey the base technology to interested manufacturing industrial partners via the Transfer of Technology. NSTL has recently solicited Expressions of Interest (EOI) from Indian battery manufacturers with sufficient experience, expertise, and willingness to absorb technology transfer and undertake production, certification, and supply of Lithium-ion (Li-ion) battery systems based on the High Power Lithium-ion Battery Technology (HPLBT). According to the EOI, 25 Ah Li-ion cells must be manufactured, tested, and evaluated to certify their safe operation in Defense applications.
Li-ion batteries for Submarines
There are indications that the adoption of lithium-ion batteries has allowed the Japanese 29CC Soryu class submarine to reduce charging time to less than one hour and double its range. According to reports, both high and low-speed performance has been significantly boosted. However, no verified data is available on the performance of the Li-ion batteries on submarines.