Charging ahead

Louise Smyth

Alexander Heilmann details some innovative automatic battery charging systems

Although electric vehicles for private local use are mostly ‘refuelled’ by hand with a charging plug, automatic charging systems are gaining more and more acceptance for utility vehicles and in industrial applications. Here, we explain the various facts and advantages.

The most important advantage of automatic charging systems for use in a wide variety of utility vehicles is that vehicle operation and workflows are not affected. The charging schedule is usually adapted to the application. For example, a bus for local passenger traffic charges its batteries during stops at bus stops. Since this does not require a person, use in driverless vehicles is also possible.

Regular, brief charging with high-charging power (up to 900A) helps to keep the batteries small, which has positive consequences on vehicle weight, costs and space requirements. Furthermore, brief intermediate charging is better for the batteries than complete charging. The amount of energy that can be transferred within the duration of a normal stop is sufficient to recharge the drive battery. This allows emissions-free transport of goods or persons to be implemented quietly and economically

Robust solution 

Multi-Contact systems are designed on the basis of high-quality contact technology for over 100,000 mating cycles. Their waterproof design enables use in outdoor areas. Furthermore, it is possible to integrate an automatic self-cleaning system that removes foreign objects such as leaves with compressed air. This increases the service life and reduces the maintenance intervals and costs. 

Flexibility in the use of automatic charging systems is ensured through interfaces allowing precise adaptation to the requirements of the application and also integration into battery management systems. In automated logistics processes the automatic charging system communicates with the vehicle as well as with the higher-level software that controls and monitors the entire charging process.

Multi-Contact systems make it possible to integrate charging stations into the existing infrastructure without immense expense. The whole contact unit does not require much space and blends into existing stops in a visually attractive way. Elaborate electronic positioning and guidance systems are not necessary. The mechanical guidance also compensates for positional inaccuracies of the bus. The flexible plug comes out of the charging station and finds its way into the funnel-shaped charging socket installed on the bus completely automatically.

Great importance is placed on safety: all live parts are protected against contact in every situation, whether plugged in or not. The power and signal contacts are not laid open until the connection is completely plugged in; the electronic activation then occurs to start the charging process. Furthermore, there are no exposed live parts such as overhead lines or power rails that can be touched.

Concerning environmental protection, it should be emphasised that the use of locally generated energy in combination with the latest storage technology and battery management systems allows efficient emission-free operation. Thanks to their intelligent features, automated charging systems can relieve the burden from the power grid, supporting the energy revolution. Therefore battery-operated buses with such charging systems are becoming a serious alternative to the combustion engine vehicles used previously.

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Alexander Heilmann is with Multi-Contact

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