German electronics company Infineon and Taiwanese power and energy management firm Delta have developed a system that integrates solar, energy storage and charging of electric vehicles.

Thanks to bidirectional inverters, the electric car is not only charged, but can also be used as a buffer storage or as household emergency backup power. More and more cars are equipped for this. Looking ahead, bidirectional energy flows could also be used to realise vehicle-to-home (V2H) and vehicle-to-grid (V2G) technologies.

On hot summer days, the share of solar power in the energy mix reaches record levels, but not when the sun is not shining. With bidirectional charging, solar power from the photovoltaic system is stored in electric cars and home batteries and fed back into the home grid in the evening hours or when needed to operate household appliances.

This protects the environment, saves money and creates incentives for switching to emission-free electromobility.

“To make a sustainable contribution to decarbonisation, we must think electromobility holistically: from green power generation to a stable, efficient grid infrastructure to storage and consumption,” said Peter Wawer, head of Infineon’s industrial power control division. “With our solutions for bidirectional charging, the electric car can be charged inexpensively with solar power at home and also serves as a buffer storage.”

A single-family home can consume an average of 10 to 15kWh of energy per day. A fully charged car battery with a capacity of 30 to 100kWh could therefore theoretically bridge a few days as emergency power. Homeowners thus secure inexpensive electricity as well as more independence in power supply.

The system provided by Delta allows a maximum continuous current of 34A and achieves peak efficiencies of more than 97.5 per cent. To increase power density, energy-efficient power semiconductors made of silicon carbide (SiC) from Infineon are used. Compared with silicon-based semiconductors, SiC reduces energy losses when converting current by around half. The size of charging stations can also be reduced by about 30 per cent. With SiC, photovoltaic systems become more powerful, charging times at fast-charging stations and wall boxes are shorter, and the range of electric cars five to ten per cent higher.

By the end of this decade, more than half of all newly registered vehicles are expected to be partially or fully electric. Green mobility can only be achieved if both vehicles and energy are carbon neutral. One key therefore lies in the use of wind and solar energy. The fluctuating availability of these energy sources though must be balanced by electrical storage systems to stabilise the grids.

Almost every second electric or hybrid car produced in 2021 used Infineon semiconductors in the inverter. Infineon power semiconductors are also setting standards in charging stations: the 50kW Hypercharger from Alpitronic is the first wall-mounted charging station that allows two cars to be charged simultaneously.