LIONIC® Energy Systems: a technology that keeps its word
The use of lithium batteries in tugger trains is convincing at the Wolfsburg automotive plant.
For several years the vehicle production plant in Wolfsburg used tugger trains to supply the production line. These e-trac- tors with trailers run on fixed routes be- tween the production stations and pro- vide them with the necessary material. From time to time they are stocked up with new material in the “supermarket” and their batteries are recharged.
The e-tractors used in the factory are equipped with 24 V/620 Ah lead acid batteries (PzS). To make use of the vehicles’ downtime in the “supermarket”, high-current charging technology for lead acid batteries is used to ensure the vehicle batteries are always charged when the tugger trains receive new material. At the end of 2013 an idea arose to equip 9 vehicles with modern lithium-ion batteries that bring significant advantagesfor this application. These include intermediate load capacity without compromising superior service life, extremely short charging times, no formation of gas duringcharging and high energy efficiency.
Easy handling in practice
The benefits during handling are particularly noteworthy: during charging with lead-acid batteries the battery cover must be opened and the vehicle battery connector must be plugged into the charger. With use of lithium batteries there is an additional charging socket in the trough at the side of the vehicle. The driver only needs to insert the charging plug. The battery automatically switches from discharging to charging mode and vice versa. Opening of the battery cover is no longer necessary because no gases are formed.
Simple conversion, convincing results
In order to achieve the minimum battery weight prescribed by the vehicle manufacturer, with the lighter lithium batteries BENNING fitted the original trough with extra weights. For dimensioning the new batteries, significant analysis was required in advance. BENNING had an excellent overview of the energy and the Ah-throughput based on the final charge data of the lead systems used to date. For this application 24 V/120 Ah lithium batteries would have been able to replace the 24 V/620 Ah lead acid batteries. For safety's sake, however, 24 V/240 Ah lithium batteries were used. In order to make charging during downtimes as effective as possible, the batteries are charged with 120 A. In this way, a completely flat battery can be completely recharged within a max. of 2 hours. This is impossible for lead-acid batterie even with high current charging technology. For this project the LIONIC® systems were leased for 1 year to test whether the modern technology proved its worth. It did -and with flying colours: all the predicted benefits were seen in practice. In addition, the systems run smoothly and without any unforeseen issues. The vehicle manufacturer is reviewing the use of using lithium-ion batteries in other areas of the operation.
Short amortisation period
The decision to go for BENNING lithium systems was all the easier as, despite higher input costs, they quickly pay for themselves due to their multiple benefits. This is especially true when battery changing is not possible during operations: in this case LIONIC® energy systems are the ideal solution due to their effective interim charging and troublefree handling.
contact: Manfred Wies
telephone: +49 (0) 28 71 / 93-233