Battery energy storage systems (BESS) are building up behind the grid to help keep up with the rising demand for power driven by everything from electric vehicles (EVs) to AI data centers. By storing excess energy, including from non-constant sources such as solar and wind, they can deliver electricity to the grid during periods of peak demand. They can also supply backup power to facilities such as factories and data centers, helping the latter manage the highly variable power demands associated with AI workloads.

But increasing the capacity and performance of these big lithium-iron-phosphate (LFP) batteries is only part of the equation. Equally important is maximizing the amount of energy that power electronics can wring out of them.

“At utility scale, even small improvements in power-conversion efficiency can have a meaningful impact on battery energy storage system performance and total cost of ownership,” said Sergio Fissore, vice president and general manager of the IPD power division at onsemi. To that end, the company is working with battery-storage supplier Sungrow to integrate its silicon-carbide (SiC) power-module technology into a new utility-scale BESS.

Sungrow's PowerTitan 3.0 platform incorporates onsemi's power integrated modules (PIMs), optimized for the three-level inverter topologies widely used in grid-connected batteries.

The "hybrid" module combines SiC MOSFETs, used in the high-frequency switching stages to maximize efficiency and power density, with silicon power devices, used in other portions of the design. This dual-material approach balances SiC's higher performance with silicon's cost to improve the “system economics” of energy storage.

Compared with the previous-generation platform, the new architecture improves inverter-level efficiency by 0.4%, according to onsemi. It supports power-conversion units rated up to 450 kW, enabling higher-power storage deployments while maintaining high conversion efficiency. Peak efficiency exceeds 99.3%, helping minimize losses and the associated heat in utility-scale systems that convert DC from the battery to AC for grid delivery.

In a large-scale BESS deployment, even small improvements in efficiency can make a big impact on both performance and cost, said Fissore. onsemi’s analysis revealed that a 0.4% efficiency boost delivered by the hybrid SiC module could add up to more than 475 megawatt-hours (MWh) of energy savings per year in a 100-MW battery energy storage installation compared to the previous module.

These savings can increase the amount of energy available for grid delivery, reduce operating costs, and improve the overall economics of storage assets, according to onsemi.

The same characteristics also enable higher overload capability and improved thermal performance, which helps energy storage systems handle the heavy demands of loads such as AI data centers while maintaining reliability. In these situations, the BESS acts as a shock absorber, supplying extra power to the data center during AI power spikes.

Chen Peng, general manager of energy storage conversion products for Sungrow's Energy Storage business, said the new architecture would help with the "deployment of higher-performance storage solutions that deliver greater value throughout the lifecycle of energy assets. By integrating advanced technologies and collaborating with strategic partners such as onsemi, Sungrow is accelerating the deployment of higher-performance storage solutions that deliver greater value throughout the lifecycle of energy assets."