For most e-bike users who ride in the city or over short distances, a shorter range and therefore a smaller battery than is currently standard on most e-bikes is sufficient. This saves costs and protects the environment. However, in order to be able to cover longer distances, this battery must be able to be charged as quickly as possible. However, it currently takes two to four hours to charge a conventional e-bike battery. This makes it difficult to start quickly once the battery is fully discharged. "That's why we want to develop a fast-charging system for e-bikes that is compact and powerful, but also user-friendly and environmentally friendly," explains Nicolaus Lemmertz, scientist at the Electrotechnical Institute (ETI) at KIT and head of the project.

The new fast-charging process is to be based on lithium-ion cells with a long service life, have a comparatively strong charging current of up to ten amps and can be charged in less than an hour at normal 230-volt sockets. The battery management system should also offer a diagnostic function: The data measured while the e-bike is in use is recorded via an Internet-of-Things (IoT) solution, analyzed and streamed in the internal Coboc cloud. They provide information about the State of Charge (SOC), i.e. the battery's state of charge, and the State of Health (SOH), i.e. its overall condition compared to a new battery. Both parameters are interdependent.

The results of the data analysis are to be made available to manufacturers and users in graphical form. This enables continuous optimization of the e-bike, corresponding adjustment of the overall system and, in terms of predictive maintenance, always up-to-date information on the battery status. "By selling e-bikes with a smart system like this, we can not only increase our market share, but also ensure greater sustainability," emphasizes Coboc Managing Director David Horsch. Within the project alliance, KIT is responsible for selecting and evaluating the lithium-ion cells in question, testing the service life of selected cells, developing the fast charging process and a diagnostic system that includes the SOC and SOH. Coboc is primarily responsible for the requirements analysis and development of the operations management system, the implementation of the IoT system with the associated server back end as well as the hardware and its integration in the electric bicycle. The project is being funded as part of the Central Innovation Program for SMEs of the German Federal Ministry for Economic Affairs and Energy (BMWi) and will run until the end of September 2021.