Thread by @jpr007

DATELINE 2009

Porsche Announces Starter Battery in Lithium-Ion Technology - News

Porsche AG is claiming that it is the first car maker in the world to offer a starter battery in lithium-ion technology
eepower.com/news/porsche-a…

The Li-ion battery has a nominal capacity of 18 Ah at 12 v = 0.216 kWh and weighs less than 6 kg or 13 lb

Porsche's conventional Lead-Acid battery has a nominal capacity of 60 Ah at 12 v = 0.720 kWh and weighs about 16 kg or 35 lb

The primary reason for developing and introducing the new battery was its lower weight

The new battery is more than 10 kg or 22 lb lighter

In sports cars built for consistently superior driving dynamics such as the two versions of the 911 GT3 and the Boxster Spyder, less weight naturally means even greater agility and driving dynamics

With its nominal capacity of 18 Ah, the lithium-ion battery through its specific features offers a level of practical output and performance not only comparable to that of a 60 Ah lead battery, but it can be even better in many cases

On a conventional car battery only about 30% of the total capacity is actually available for practical use due to the configuration of the system

- but this restriction does not apply to the lithium-ion battery

On the contrary - through its characteristic structure and the independence of the chemical composition of the electrolytes from the charge status – a lithium-ion battery consistently offers almost 100% of its current-flow capacity

Delivery of power by the lithium-ion battery throughout its useful charge range is likewise significantly better, providing its full power, for example, when starting the engine almost independently of the current charge level

After the engine has started the new Porsche battery shows further benefits in the charging process, with its smaller internal resistance allowing it to take more current than a conventional battery and thus re-charge more quickly

A lithium-ion battery has a number of other advantages over a lead-acid battery :

- it allows a significantly greater number of charging and discharging cycles

- self-discharging effect is lower

- the service life of the battery longer

The lithium-ion battery being introduced by Porsche is made up of a wound film of carbon and iron phosphate with a ceramic film serving as a separating layer in between that is moisturised by the electrolyte

Compared with other types of lithium-ion batteries using a combination of manganese oxide, cobalt oxide or nickel, this lithium-iron-phosphate LFP battery, as it is called, offers advantages when used as a starter battery

It is robust and consistently guarantees the required voltage of 12V in the car’s on-board network

The lightweight battery is made up of four cells and integrated control electronics or battery management system

This battery management system protects the battery from major discharge and guarantees a consistent charge level within the individual cells

Once battery voltage drops below a certain threshold, a warning signal reminds the driver to re-charge the battery either simply by driving the car through the power of the engine running or by means of a conventional battery charger

In its length and width the lithium-ion battery comes in the same dimensions as the regular battery, but is approximately 70 millimetres or 2.8" lower

The fastening points, electrical connections and voltage range are fully compatible with the respective models, allowing simple and quick replacement of the standard lead battery by the lightweight unit, for example when racing on the track

The new lithium-ion battery will be available as of January 2010 for the 911 GT3, 911 GT 3 RS, and Boxster Spyder as an option delivered with the car, selling at a price in the German market of €1,904 including 19% value-added tax

The battery is delivered as a separate unit together with the car and may subsequently be fitted as an alternative to the regular conventional starter battery

The cars are delivered with both batteries so they are ready for use throughout the whole year

While the lightweight battery offers a very high standard of everyday driving qualities, its starting capacity is limited at temperatures below 0°C or 32°F due to its specific features

The new lithium-ion battery will also be available for retrofitting from February 2010 on the three models mentioned from Porsche Tequipment

The sales price in Germany when retrofitted after delivery of the car is €2,499 including 19% value-added tax