Mercedes-Benz is researching a new type of solar module that could be seamlessly applied to the bodywork of electric vehicles – similar to a wafer-thin layer of paste. At 5 micrometers, the paste is significantly thinner than a human hair, weighs just 50 grams per square meter (less than half an ounce per square foot) and is packed full of energy. The active photovoltaic surface can be applied to any substrate, Mercedes-Benz said, and the solar cells have an efficiency of 20%.

The energy generated by the solar cells is used to drive or feed directly into the high-voltage battery. The photovoltaic system is permanently active and also generates energy when the vehicle is switched off. In the future, Mercedes-Benz said this could be a highly effective solution for increased electric range and fewer charging stops.

The yield depends on levels of shade, the intensity of the sun and geographical location. Statistically, Mercedes-Benz drivers in Stuttgart, Germany cover an average of 52 kilometers (approx. 32 miles) a day. Around 62% of this distance would be covered using solar energy, the company said. In Los Angeles, Mercedes-Benz said there could even be a surplus of energy from solar radiation. The driver could cover 100% of their driving distance on average by solar energy. The surplus achieved could be fed directly into the home network via bidirectional charging.

The solar paint contains no rare earths and no silicon, only non-toxic and readily available raw materials, Mercedes-Benz said. The company also claims the paint will be “easy to recycle” and “considerably cheaper” to produce than conventional solar modules. The Mercedes-Benz research department is currently working to use the new solar paint on all exterior vehicle surfaces – regardless of their shape and angle.

Power converter increases battery efficiency through control at the cell level

Mercedes-Benz said it is also working on a programmable micro-converter that would go beyond the limits of current electrical inverter systems. The basis for this is the integration of these micro-converters directly at the battery-cell level, which could enable individual control of battery-cell pairs as well as communication between cells.

To realize this, a power converter consisting of several micro-converters is connected directly to any number of cell pairs. This power converter makes it possible to regulate cells individually and also the level of output voltage. The manufacturer said current research results show it is possible to provide a constant HV output of 800 volts, regardless of the state of charge and the state of health of the individual cells. The output voltage of this vehicle battery is no longer dependent on the number of cells connected in series. The number is determined purely by the desired performance and capacity class.

This technological approach could also increase electric range and optimize energy flow for bidirectional charging, Mercedes-Benz said, and it could deliver new levels of freedom in the modularisation of electric drives.

The new technology has the potential to enable the integration of several power electronics functions into the HV battery. This means various power components could be realized by the HV battery itself, achieving a whole new level of integration in electric vehicles, the company said. The improved use of space as well as a reduction in the number of variants would open up entirely new freedoms in the layout and design of electric vehicles, Mercedes-Benz said.