Using electric cars as buffer storage for solar power

Infineon Technologies AG and Delta Electronics have developed a three-in-one system that combines solar, energy storage and EV charging. Thanks to bidirectional inverters, the electric car is not only charged but can also be utilised as a buffer storage or as household emergency backup power. More and more cars are equipped for this. Bidirectional energy flows could also be employed to realise new vehicle-to-home (V2H) and vehicle-to-grid (V2G) solutions.

"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," says 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 use an average of 10-15kWh of energy per day. A fully charged car battery with a capacity of 30kWh to 100kWh could theoretically bridge a few days as an emergency power solution. Homeowners could secure inexpensive electricity as well as more independence in power supply.

The new system provided by Delta enables a maximum continuous current of 34A and attains peak efficiencies of more than 97.5%. Energy-efficient power semiconductors made of SiC from Infineon are employed to increase power density. Compared to silicon-based semiconductors, the compound material SiC lowers energy losses when converting current by around half. The size of charging stations can also be decreased by about 30%. With SiC, photovoltaic systems become more powerful, charging times at fast-charging stations and wallboxes are shorter, and the range of electric cars is 5-10% higher.