SoftBank Joins Forces With Cosmos Lab and DeltaX to Build 1 GWh Battery Production Line in Japan for AI Data Centers by FY2027

SoftBank Group Corp. is moving to manufacture next-generation battery cells at scale inside Japan, partnering with South Korean firms Cosmos Lab and DeltaX to produce energy storage systems designed specifically for data centers running AI workloads. The three companies aim to reach annual output of one gigawatt-hour (GWh) by fiscal year 2027, targeting the surging power demands of artificial intelligence infrastructure. SoftBank's mobile unit will lead the initiative from its existing Sakai, Osaka facility.

What makes this move notable is its direct alignment between telecom infrastructure, AI power requirements, and sovereign battery manufacturing. Neither SoftBank nor the South Korean partners are newcomers to energy storage, but the specific focus on data center demand — rather than consumer electronics or electric vehicles — signals a deliberate pivot. The Sakai plant, already operational for other production lines, will be retooled for the new battery line, suggesting a faster-than-anticipated ramp given the facility's existing footprint.

The deal reflects intensifying competition across Asia to secure domestic battery supply chains for AI-driven power needs. Data centers consuming gigawatts continuously require energy storage that traditional lithium-ion packs may not efficiently address at scale, raising questions about which chemistry or form factor Cosmos Lab and DeltaX bring to the partnership. SoftBank's move places it alongside a broader regional push — including similar investments in South Korea and Taiwan — to reduce reliance on imported battery cells as AI compute demand accelerates.