SoftBank Launches Gigawatt-Hour Battery Business to Power AI Data Centers in Japan

SoftBank said in a press release that it will use its Osaka Sakai AI Data Center as the core hub for its AX Factory and GX Factory. The center is being developed on the former Sharp Corporation site in Sakai City. At the GX Factory, SoftBank "plans to begin manufacturing battery cells and energy storage systems from the fiscal year ending March 31, 2028 (FY2027), with the aim of achieving mass production on a gigawatt-hour (GWh)-per-year scale by around FY2028."

The initiative is being developed in collaboration with two technology partners, the company said. For battery cells, SoftBank is working with COSMOS LAB to jointly develop "innovative battery cells that combine highly safe and non-flammable characteristics with superior energy storage performance." The zinc-halogen batteries use pure water as their electrolyte, and their "key feature is its ability to eliminate fire risks associated with the currently dominant lithium-ion batteries." SoftBank and COSMOS LAB aim to "establish technology for mass production at an early stage, and commence mass production around FY2027."

For energy storage systems, SoftBank has partnered with DeltaX Co., Ltd. to develop and manufacture a system that achieves "world-class energy density." DeltaX's Cell Connecting System design and Cell to Pack technology "make it possible to maximize the performance of each individual battery cell," and SoftBank will integrate these with its AI-based energy management system for power demand forecasting. The goal is to reach "mass production on a GWh-per-year scale."

SoftBank plans to deploy the Japan-produced batteries at its large-scale AI data centers and also "provide them sequentially for grid applications in Japan, as well as for factories and other industrial uses, as well as for residential use, with a view to expanding into global markets over the medium term." The company is targeting "annual revenue of over 100 billion JPY for its domestic battery business by FY2030."

The innovative battery cells are described as "the world's first to integrate the technologies of two types of next-generation batteries" by using a halogen-based cathode and zinc anode. SoftBank noted that because the cells "do not use a flammable organic electrolyte and instead use pure water as the electrolyte, the risk of ignition does not arise in principle," while key raw materials like halogen and zinc can be "procured locally in Japan, helping to strengthen the supply chain."

For BESS, SoftBank said it will leverage DeltaX's proprietary technologies to achieve a storage capacity of 5.37 MWh in a standard containerized unit and aims for comparable or greater capacity with the new cells. By incorporating AI-driven EMS, the system will enable "optimal control of charging and discharging" for efficient and stable operation amid fluctuating electricity demand and renewable generation.

- ANI