SoftBank Plans Battery Business to Power AI Data Centers

SoftBank Corp. on Monday said it will start manufacturing battery cells and energy storage systems in Japan, adding a power-storage business to support rising electricity demand from artificial intelligence data centers.

The telecom arm of SoftBank Group will use the AI data center it is developing on the former Sharp Corp. factory site in Sakai City, Osaka Prefecture, as the core hub for the new business, the company said in a 11 May press release.

The site will house an AX Factory for AI data center operations and AI infrastructure hardware manufacturing, and a GX Factory for next-generation batteries, solar panels and related products.

SoftBank plans to begin manufacturing battery cells and energy storage systems in the fiscal year ending 31 March 2028, with mass production targeted at a gigawatt-hour-per-year scale around fiscal 2028.

The batteries will first be deployed at SoftBank’s large-scale AI data centers in Japan, before being supplied for grid applications, factories, other industrial uses and homes. The company said it may expand into global markets over the medium term.

The move reflects a broader shift in the AI economy, where access to power, cooling and data center capacity is becoming as important as access to chips and software models.

SoftBank said the battery business is aimed at building next-generation power infrastructure as AI adoption drives electricity demand.

SoftBank is partnering with South Korea’s COSMOS LAB to jointly develop zinc-halogen battery cells. The company said the cells use pure water as an electrolyte and do not use flammable organic electrolyte, reducing the fire risk associated with lithium-ion batteries.

SoftBank and COSMOS LAB aim to establish mass-production technology at an early stage and begin mass production around fiscal 2027.

For energy storage systems, SoftBank is working with DeltaX Co. to develop and manufacture systems that it says can achieve world-class energy density.

DeltaX’s cell-connection and cell-to-pack technologies are intended to reduce components, limit unused space and improve storage performance. SoftBank said DeltaX has achieved 5.37 MWh of storage capacity in a standard containerized lithium-ion battery energy storage system and aims for comparable or higher capacity using the new battery cells.

SoftBank also plans to integrate an energy management system with AI-based power demand forecasting developed through its electricity business. The system will control charging and discharging to match electricity demand and renewable-energy generation, the company said.

The battery push builds on SoftBank’s earlier plan to turn part of Sharp’s Sakai LCD panel plant into a large-scale AI data center. In June 2024, SoftBank and Sharp said the planned data center would cover about 750,000 sq m of floor area, start with more than 150 MW of power capacity and potentially expand to more than 400 MW.

SoftBank said then that it would use the center for its own generative AI development and other AI-related businesses, while also providing capacity to universities, research institutions and companies.

The new domestic battery business is expected to generate more than ¥100 billion in annual revenue by fiscal 2030, SoftBank said.

SoftBank Corp. reported record revenue of ¥7.04 trillion and record net income attributable to owners of ¥550.8 billion for the fiscal year ended 31 March 2026, giving the telecom unit earnings momentum as it steps deeper into AI infrastructure.

The business also fits into SoftBank Group’s larger AI strategy. Masayoshi Son’s investment company has been increasing exposure to AI through OpenAI, Arm, data centers and other infrastructure-linked assets.

Reuters reported that SoftBank Group’s OpenAI-related financing and other AI commitments are drawing investor scrutiny, including its planned investments tied to Stargate data centers and other infrastructure projects.

The battery plan shows how that AI strategy is reaching into physical infrastructure. As data centers require more reliable electricity, companies are moving beyond software and model development into power systems, storage, cooling and grid integration.

“We will actively promote initiatives to ensure a stable supply of electricity and enable efficient energy utilization while contributing to the development of next-generation power infrastructure in Japan,” SoftBank said.