In a major leap for India's push towards self-reliance in the defence sector, the Indian Navy and Mazagon Dock Shipbuilders Limited (MDL) have successfully replaced foreign-made submarine batteries with domestically produced alternatives.
Moving away from imported German technology, the fleet's critical energy systems are now being supplied by Mumbai-based Exide Industries.
Records indicate that the initial three vessels of the Project-75 Scorpene class—INS Kalvari, INS Khanderi, and INS Karanj—were powered by battery banks acquired from Hagen Batteries in Germany.
However, driven by a strict commitment to equipment indigenisation, MDL shifted its procurement strategy.
Starting with the fourth submarine, INS Vela, and continuing with subsequent vessels like INS Vagir and INS Vagsheer, the Navy awarded contracts to Exide Industries to supply these essential power systems.
For conventional diesel-electric submarines, the main battery bank is one of the most vital and technologically complex components.
Comprising roughly 360 individual cells per vessel, this massive energy storage framework serves as the sole source of power for both propulsion and vital onboard electronics when the submarine is completely submerged.
Consequently, the performance, endurance, and safety of these batteries directly dictate the vessel's underwater range, acoustic stealth capabilities, and overall combat readiness.
The Scorpene fleet, constructed at MDL under Project-75 through a technology transfer agreement with France’s Naval Group, serves as the modern backbone of India’s conventional submarine arm.
Historically, the highly specialized batteries required for these vessels were manufactured by only a handful of international firms.
Relying on overseas suppliers introduced long-term strategic vulnerabilities, ranging from unpredictable lifecycle costs and limited spare parts to potential supply chain bottlenecks during geopolitical tensions.
Shifting battery production to Indian soil effectively neutralizes these foreign dependencies while delivering notable economic benefits.
Official data reveals that sourcing these heavy-duty systems from Exide Industries has saved the national exchequer approximately ₹18.80 crore in foreign exchange.
Beyond the immediate financial advantages, domestic manufacturing ensures that the Indian Navy benefits from rapid battery replacement cycles, dedicated local technical support, and a highly secure supply chain that remains resilient during international crises.
Engineering submarine batteries is an exacting scientific process.
The units must function flawlessly under extreme and unforgiving maritime conditions.
This requires robust resistance to intense vibrations, advanced thermal management to prevent overheating, and strict gas emission controls to avoid hazardous buildups inside the sealed hull.
Furthermore, the batteries must endure frequent, deep power discharge cycles without any compromise in reliability during prolonged patrol missions.
Mastering this specialized manufacturing process marks a prominent milestone in India’s broader naval self-sufficiency campaign, which increasingly targets critical technologies like combat management systems, sonars, and electronic warfare suites.
Looking ahead, this achievement establishes a robust industrial foundation for upcoming domestic shipbuilding initiatives, such as the ambitious Project-75I.
Furthermore, India's growing domestic battery ecosystem is expected to play a crucial role in future fleet upgrades, paving the way for next-generation battery chemistries and seamless integration with the indigenous Air Independent Propulsion (AIP) system currently being developed by the Defence Research and Development Organisation (DRDO).
