Infineon Technologies is now supplying silicon carbide (SiC) power semiconductors to Fox ESS, a renewable energy solution provider, to enhance the efficiency of its residential energy storage systems (ESS). Leveraging Infineon’s CoolSiC MOSFETs 1200 V G2 in the Q-DPAK package, Fox ESS has reduced switching losses by 70%. As a result, the company’s PQ3-Ultra energy storage system achieves a peak photovoltaic (PV) inverter efficiency of up to 98.78% in grid-tied operation and a peak battery charge/discharge efficiency of up to 98.47%.
“With our SiC MOSFETs in the Q-DPAK package, we are enabling a new level of efficiency, thermal performance and design flexibility for residential energy storage systems,” said Amit Raut, Application Manager Photovoltaic and Residential ESS at Infineon. “Fox ESS is demonstrating how advanced SiC technology can translate into measurable system-level gains and support the broader adoption of clean energy solutions in homes worldwide.”
Compared with conventional bottom-side-cooled designs, the Q-DPAK package supports improved PCB layout, helping to reduce parasitic effects and stray inductance while enabling superior thermal management. Its compact footprint supports space-saving system designs, while compatibility with automated assembly simplifies cost-efficient, scalable manufacturing.
Silicon Carbide Technology for High-Performance Energy Storage Solutions
Within Fox ESS’s energy storage system, Infineon’s CoolSiC MOSFETs 1200 V G2 in the top-side-cooled Q-DPAK package deliver optimised thermal performance, system efficiency and power density. Infineon has specifically designed the devices for demanding applications requiring high performance and reliability. Featuring Infineon’s advanced .XT interconnection technology, they reduce thermal resistance and operating junction temperature, while the trench gate architecture helps lower switching losses.
“The collaboration with Infineon is a major pillar of our strategy to deliver high-performance energy storage solutions,” said Daniel Deng, R&D Director at Fox ESS. “Infineon’s CoolSiC technology offers superior efficiency and outstanding reliability, values that perfectly match our philosophy. By working together, we will further advance the performance of residential energy storage systems and accelerate the adoption of renewable energy.”
For its hybrid ESS solution combining the PQ-H3-Ultra-10.0 inverter with the EQ3300-5 battery, Fox ESS has achieved a System Performance Index (SPI) of 97.0 percent in a recent test by HTW Berlin University of Applied Sciences and AQUU Research. This ranks Fox ESS first in the 10-kW class among all hybrid inverter and storage systems tested in 2026 and marks the highest SPI score recorded since the evaluation was launched in 2018. Over the past three years, Fox ESS has installed more than 890,000 PV inverters and over one million batteries in more than 70 countries.
