Automotive Engineer is the magazine of the EAEC

Automotive Engineer

Porsche moves flywheels to the back of the grid

Batteries better suited to passenger cars

James Scoltock in News.
  • Published in News.

In a spin: Flywheels don't offer enough energy density for passenger vehicle applications

Porsche won't introduce flywheel hybrid technology to its passenger vehicles. The firm says flywheel systems – as used in its concept GT3 RS and 918 RSR race cars – don't provide enough energy to improve efficiency and performance. Instead Porsche will continue to develop its battery technology.

The firm has already brought hybrid versions of the Cayenne SUV to the market which uses a nickel-metal hydride battery and a plug-in Panamera sedan which uses lithium-ion technology.

Porsche's member of the board for research and development, Wolfgang Hatz said: “The amount of energy in a flywheel isn't enough, the GT3 RS has 0.2kWh and considering the average electric consumption you can run it for 1km in electric mode. This system is interesting for a race car and it's really power dense, but to fulfil efficiency targets you need energy density.”

Porsche's latest vehicle, the 918 Spyder, uses a 6.8kWh lithium battery pack and 210kW electric motor which gives the plug-in hybrid an electric range of up to 31km. Combined with its 4.6 litre V8 gasoline engine the vehicle can reach 345km/h and can hit 100km/h in 2.8 seconds.