Modular Utility BESS: The Highlight Of Canadian Solar’s Subsidiary At RE+ 2025

e-STORAGE, a part of CSI Solar Co., Ltd., has introduced its modular battery energy storage system (BESS) – FlexBank 1.0 – with a focus on utility-scale storage applications in the US market. An expansion of its BESS portfolio, this product features a modular cabinet-based architecture, which the company calls ‘open frame’. Each cabinet is equipped with Lithium Iron Phosphate (LFP) battery cells, each with a capacity of up to 314 Ah. Each battery unit is built by connecting 104 cells in series. According to the company, in a system configuration of 4*4*1P104S, up to 16 identical battery units can be connected in parallel, resulting in a maximum storage capacity of up to 1,672 kWh. Given its flexible modular design, the storage capacity can be expanded to up to 8.36 MWh of energy by combining 5 cabinets together. 

Among the key advantages, the company emphasized logistics and installation. Each cabinet, acting as an individual building block of the whole storage system, can be transported individually and installed at the site in a simplified manner compared to the so-called ‘all-in-one' cabinet-based alternatives. The cabinet features a skid-mounted design, which supports either a side-by-side or back-to-back layout. e-STORAGE emphasizes that this flexibility can help meet both ends of keeping the EPC cost down and maximizing project energy density. 

With a built-in power conversion system (PCS), the BESS supports an AC-coupled configuration, making it suitable for projects that augment its existing capacity. It is also compatible with a DC-coupled BESS configuration.  

On the safety front, each cabinet, equipped with a liquid-cooling mechanism, features heat barriers at an individual cell level. This system is designed with a 3-level protection system to mitigate potential risks stemming from electrical hazards. The company explained that, in combination with modular design and cabinet-level thermal management, it can limit thermal propagation between cabinets, thereby mitigating potential fire risk. 

Colin Parkin, President of e-STORAGE, said, "FlexBank 1.0 is the strategic evolution of our utility-scale energy storage platform, engineered to address our customers' critical needs for safe, adaptable, and cost-effective solutions. By dramatically simplifying deployment, we are providing a more reliable and adaptable technology that will accelerate the global transition to renewable energy and deliver tangible value for developers and investors." 

This product is expected to be commercially available in 2026.