Opportunity Charging

What is opportunity charging? 
Opportunity charging supplies electric vehicles with small energy packages at regular intervals, often during operation. 

Opportunity charging is mainly used for electric commercial vehicles such as buses, vans and lorries that have regular breaks and defined routes. The concept is predestined for use in public transport. For example, city buses that stop at fixed stops can be charged efficiently at these points. 

This charging option is also ideal for commercial and industrial vehicles that have fixed delivery or service routes. These include, in particular, electric industrial trucks such as forklift trucks and driverless transport vehicles. In addition to public transport, the technology is particularly useful for vehicles in logistics centres and factories, where constant operational readiness is required and regular, short stops provide the ideal opportunity for recharging. 

Opportunity charging - ideal for the continuous charging of lithium-ion batteries 

Lithium-ion batteries are particularly suitable for opportunity charging as their chemical structure allows frequent partial charges to be carried out without any negative effects on battery life. In contrast to lead-acid batteries, which lose capacity with frequent partial discharges, lithium-ion batteries can be partially charged repeatedly without their energy level dropping significantly. 

This property makes them ideal for application scenarios in which regular, short charging intervals are possible, while at the same time protecting them from the risks of overcharging and overheating. 

The combination of opportunity charging and lithium-ion battery technology helps to overcome the biggest challenge of electromobility - limited range and long charging times - by enabling fast and efficient recharging during operating hours. 

Opportunity charging can be implemented in various forms. Which of these methods is best suited to the respective application depends on the specific requirements of the application area and the existing infrastructure. In general, opportunity charging can be realised in the following variants: 

• Static charging systems: Fixed charging stations at bus stops or terminals where vehicles regularly charge for short periods of time 
• Mobile charging systems: Portable or temporary charging solutions that can be used flexibly at different locations 
• Automated charging systems: Advanced systems such as automated pantographs or inductive charging systems that enable fast and automatic charging without human intervention 
• Dynamic charging: Technologies such as charging while driving through inductive charging points embedded in the road 
• On-route charging: Installation of charging infrastructure along routes that enable fast, high-current charging

How opportunity charging is technically realised 

But how exactly does charging work on a technical level during operation or during short breaks? Three scenarios are possible for the realisation of opportunity charging: charging via plug connections, charging with sliding contacts or the use of inductive point charging systems. 

Opportunity charging with plug connections 

With conventional plug-in charging, the electric vehicle is connected to a power source using a charging cable. This method could theoretically be used for opportunity charging during short work breaks. In practice, however, it is often the case that the manual effort involved in connecting and disconnecting the charging cable means that not every possible charging opportunity is utilised. 

Opportunity charging with sliding contacts 

Charging with sliding contacts has traditionally been used for the automated charging of automated guided vehicles (AGVs). Here, permanently installed sliding contacts on the route interact with a corresponding mating contact on the vehicle. 

Opportunity charging via inductive point charging systems 

Inductive point charging systems enable contactless energy transfer and offer a safe and reliable solution for opportunity charging. This system utilises magnetic fields to transfer energy wirelessly, eliminating the risk of connection errors and simplifying maintenance. 

Inductive charging is particularly suitable for environments where a fast and efficient supply of energy is required without vehicles being out of service for long periods. By automating the charging process, problems such as discharged batteries or vehicle breakdowns are avoided, making this technology a key component in opportunity charging.