Hybrid cars: differences between light, full and plug-in hybrids

Hybrid cars were the best-selling cars in Italy in 2024. If until a decade ago hybrid was synonymous with "Toyota" with the technology brought to debut first by the Prius and then by the compact Yaris, today the situation has drastically changed. It is therefore important to know the difference between the various technologies in order to make the right choice when purchasing.

Mhev (Mild Hybrid Electric Vehicle) systems, often christened 'light hybrids', are the first step in electrification. Although there is no difference in type approval, Mild Hybrid versions have a parallel electric system, powered by 12 or 48 volt batteries working in conjunction with a small electric motor. Capable of recovering energy during braking, the 12-volt Mhev system is not able to move the tyres independently but provides energy during vehicle restart, thus reducing fuel consumption and pollutant emissions. This is different for the 48-volt mild hybrids, which are now capable of moving the car in full electric mode for a few kilometres.

The second step of electrification sees the presence of Hev (Hybrid Electric Vehicle) models, increasingly christened as full hybrids, where the electric motor works together with the Ice (Internal Combustion Engine) and is able to travel 100% in electric mode for more kilometres than 48-volt mild hybrids. The electric motor contributes more to lower fuel consumption and emissions than Mhev systems, but it takes up more space and involves higher costs and weight. The batteries are recharged during braking and thanks to the presence of the combustion engine, while there is no socket to connect to charging stations.

For 'plug-in' models, one has to switch to the Phev (Plug-In Hybrid Electric Vehicle) where there is a combustion engine and the electric motor is also recharged from the wall socket. The zero-emission range can reach over 100 kilometres and petrol consumption is significantly reduced when travelling with a charged battery. Completely opposite situation when the battery is empty, where plug-in cars become anything but economical and environmentally friendly.

Hybrid range extenders are vehicles where the internal combustion engine is only used as a current generator to recharge the traction battery when the charge level is low. Erevs include the Nissan X-trail e-Power, where there is no power plug but the petrol-powered internal combustion engine is only used to generate power to charge the electric motor battery and not to generate traction for the tyres. Another range extender application comes from the Mazda Mx-30 R-Ev, and it is recharged, unique among production cars, by an 830 cc, 75 hp Wankel-type rotary engine. There is an electric motor to drive the front wheels and it can also be recharged from the charging stations.