Winchester, UK - International automotive supplier, Continental AG, has become the world's first manufacturer to start series production of lithium-ion batteries for use in hybrid drive cars.

Continental's Powertrain Division has invested more than three million euros in developing a manufacturing capacity at the Nuremberg site.

Compared with nickel-metal hydride battery technology currently in use in hybrid vehicles, lithium-ion batteries, the latest generation energy storage units, offer significantly greater storage capacity. The battery which Continental has developed weighs around 25 kg and requires an installation volume of some 13 liters. These characteristics allow the electric motor to boost the combustion engine by up to 19kW, making fuel savings during acceleration or when starting off. The battery is charged when the vehicle brakes or decelerates.

The regenerative braking or recuperation is controlled by the power electronics. Like the integral automatic start-stop function which automatically switches off the engine when the vehicle comes to a standstill and switches it on again when starting off, recuperation is included as part of Continental's hybrid modular system which combines all the hybrid technology expertise in a single package.

The lithium-ion battery produced in Nuremberg, including the hybrid technology, is to be installed as standard in the new Mercedes S400 BlueHYBRID, which will be available from the middle of 2009. By adopting the battery technology, the luxury class sedan with its six-cylinder gasoline engine will achieve a consumption rate of 7.9 liters of super gasoline per 100 kilometers, equating to carbon dioxide emissions of 190 grams per kilometer.

"The battery has to operate safely and reliably for the whole of the life cycle stipulated by the vehicle manufacturer, and that's at least ten years", stresses Jorg Grotendorst, head of the Hybrid Electric Vehicles Business Unit in Continental's Powertrain Division.

The reliability performance is achieved by a battery management system which monitors the battery so that it is always within the optimum working range. The electronics compare the battery's overall condition, temperature and energy reserves against its age; and safety circuits prevent the energy storage unit from becoming too hot.

A Cell Supervision Circuit (CSC) monitors the individual cells and ensures their optimum interaction. The CSC balances the charge levels of all the cells in the battery to ensure the cells are not permanently subjected to uneven loads. The battery management system guarantees that the lithium-ion batteries will last - with unimpaired functionality, power and safety - for the required ten years or 160,000 to 240,000 kilometers. Batteries produced since last year as part of the preproduction series have been artificially aged in the course of exhaustive text cycles in order to simulate their use in vehicles over many years.

Continental is also developing innovative recycling procedures that will allow at least 50 percent of the content of lithium-ion cells to be recycled.

Continental started pre-series production of lithium-ion batteries in Berlin during 2007. Since last year the series production equipment was planned and installed in the Nuremberg plant involving an investment of 3.3 million euros with 23 new jobs being created in the Production Department and related areas. 15,000 lithium-ion batteries can be produced annually in the production facility covering 300m2 with capacity for volumes to be doubled at short notice.