The importance of battery technology and its development has become central to the emergence of alternative-powertrain vehicles on a global scale. This includes the micro-hybrid (stop-start) dimension, which is growing rapidly.
Output of Varta AGM (absorbent glass mat) and EFB (enhanced flooded) batteries from Johnson Controls’ plants in Europe is planned for what the company terms a significant expansion to meet market requirements. It says that demand from OEM customers and the aftermarket for AGM batteries is now showing the fastest product growth in the car battery market, driven by CO2 reduction targets and consumer calls for even better fuel economy. Since 2002, more than 7 million AGM batteries have been produced by Johnson Controls at its Zwickau, Germany, plant.
The company estimates that vehicles equipped with start-stop technology will represent some 70% of all those produced in Europe by 2015. From 2012, the car fleet maximum for CO2 will be 130g/km in Europe.
Christian Rosenkranz, Vice President, Product Engineering, Johnson Controls Power Solutions EMEA, said that as the heart of the start-stop system, the battery is becoming an important part of new environmentally responsible technology.
Five new EFB batteries ranging from 6 to 80 A·h have just been launched by the company for cars including the Fiat 500 and Toyota Yaris. EFB technology represents a midway position between a regular starter battery and an AGM. It uses thicker plates, higher-density active material, and polyester fleece within the envelope separators to increase cyclic durability, which is said to be about double that of a standard starter battery.
As well as OEM requirements, Varta stop-start batteries are also experiencing increasing demand in the aftermarket. Johnson Controls has just launched a new range of AGM and EFM types to meet that need. The expanded range features five stop-start branded AGM batteries with capacities of 60 to 105 A·h for micro-hybrid applications incorporating the full range of stop-start benefits, including regenerative braking, intelligent voltage control, and alternator passive boost.
Rosenkranz added that as hybrid technology provides an opportunity for passive boost (when the alternator is switched off to give more power to the wheels), the battery has to provide energy support. Without correct battery technology, these functions would not work, he warned, and the cost and environmental benefits of reduced fuel consumption and emissions would be lost. It would also lead to accelerated failure of the replacement battery, particularly if a non-AGM battery was fitted into an AGM application.
Vehicles with automatic stop-start technology require specific batteries; the wrong battery not only impairs the function with environmental consequences but also reduces the service life of the battery itself. Tests have shown that conventional flooded batteries lose 7 to 16% of their available capacity after just one week of being used in a stop-start vehicle.
Johnson Controls-Saft supplies lithium-ion batteries to the automotive industry; they are used in the Mercedes Benz S-class hybrid and BMW ActiveHybrid 7.