Lightweight garage #1 Lithium-iron-phosphate starter battery @ Porsche 911 GT3 RS (997.2)

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Lightweight garage, News

The vehicle

We parked the Porsche 911 GT3 RS, also known as the 997.2, behind the first garage door. The car weighs around 1,445 kg and its six-cylinder boxer engine produces a maximum of 450 hp and delivers up to 430 Nm of torque.

This manual transmission was built from 2009 to 2011 in order to obtain homologation for the racing car. In addition to the use of carbon fiber, aluminum struts and polycarbonate windows, it was also the first car with a lithium-ion starter battery as of February 2010.

The technology

For the starter battery, Porsche used a positive electrode made of lithium iron phosphate for selected models for the first time. This is special because lead-acid batteries have been established since their introduction at Cadillac over 100 years ago and are still the state of the art. Whereas in conventional starter batteries, disordered chemical reactions build up or break down the electrode, lithium is stored in or removed from the grid structure in lithium batteries.

Although the lithium iron phosphate technology used at the time was still very temperature-sensitive and could not provide the required starting power below 0° C, it was charged more quickly during operation and offered a longer service life.

The new starter battery also met the usual installation standards and could be retrofitted or replaced for the racetrack only. The cost of the battery was around €2,000 or €2,500 for retrofitting.

The lightweight aspect

The special feature of this solution from a lightweight construction point of view was that the overall height was reduced by around 70 millimeters and the weight was reduced by around 10 kg to 6 kg compared to the 60 Ah reference starter battery.

Due to the higher energy density and the advantageous discharge behaviour, this technology opens up the possibility of using the available installation space for other purposes or optimizing the installation position, for example to improve the centre of gravity. Reducing the weight of a sports car also has an effect on driving performance. A low mass enables higher acceleration and tighter cornering.

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