The “Tiny Power Box 2” is the world’s thinnest bidirectional 11-kW onboard charger for electric vehicles, measuring just five centimeters in height according to Die Presse.
No electric car operates without an onboard charger tucked away in its underframe, managing the transfer of electricity from a standard socket into the vehicle battery. Research teams led by Silicon Austria Labs in Graz transformed this essential component into a versatile power unit that extends beyond standard vehicle charging.
“[T]he Tiny Power Box 2” supplies the onboard electronics—including the radio and headlights—with energy while driving, project manager Christian Mentin told Die Presse.
Achieving this required careful engineering because the vehicle’s onboard electronics operate at a different voltage than the main propulsion system. The standout feature of the hardware allows the vehicle battery to function as a home energy storage system.
When a residential photovoltaic system fails to generate electricity at night for water heating, a parked electric car plugged into a home charging station steps in as a power source. The car battery automatically switches to power delivery once fully charged.
“With this, we succeed in using renewable energies even more efficiently,” Mentin told Die Presse.
“[O]ne hurdle, however, is that the various network operators in Europe do not have uniform standards for feeding electricity back in,” Mentin told Die Presse. Because of this regulatory fragmentation, an international rollout of the technology is not in sight.
The project focused primarily on miniaturizing the charger, reducing its weight, and maximizing charging efficiency. The resulting device measures roughly five centimeters in height, making it thinner than all currently available conventional models worldwide.
Advanced semiconductor technologies enabled this compact volume while supporting extra functionalities. Managing thermal output proved to be one of the primary engineering obstacles during development.
“[W]e have achieved an efficiency of 96 percent, which is better than conventional chargers,” Mentin told Die Presse. He said that the predecessor model achieved 98 percent efficiency, but engineers made compromises to fit upgraded functions into a smaller housing.
This efficiency rate means roughly four percent of energy converts to heat during charging, requiring precise thermal design to prevent overheating across more than one hundred internal components. Research teams built simulation models to calculate thermal interactions across the hardware.
“[T]he creation of the simulations was an essential part of the project,” Mentin told Die Presse.
Industrial partners contributing to the development include Austrian firms such as Infineon, Fronius, AVL List GmbH, and TDK Electronics, alongside companies from Germany and Italy.
Silicon Austria Labs has researched onboard chargers since 2019, building a repository of expertise utilized by international automotive manufacturers.
