How the e-cargo bike can last longer New solutions to increase the intensity of use and extend the service life of e-cargo bikes
In search of technical possibilities to use electrically assisted bicycles and cargo bikes more efficiently, researchers at Technische Universität Braunschweig investigated various subsystems of the e-cargo bike product-service system. The aim was to develop technical solutions and concepts in the fields of “business model”, “battery”, “app and service” and “recycling”. Together with their research partners from science and industry, they have now presented their results at the final event of the joint project “LifeCycling²” at the Automotive Research Centre Niedersachsen (NFF) Braunschweig.
No exhaust fumes, less noise: supply chains in which an electric cargo bike takes over the ‘last mile’ instead of a car are a promising alternative on the way to emission-free mobility in cities. But how long does the battery last? Can I influence its lifespan? And what happens to the bike when the battery has reached the end of its life? These are the questions that a research team from TU Braunschweig and TU Clausthal, together with bicycle manufacturers, software developers and service providers from the bicycle industry, have been dealing with in the joint project “Life Cycling²” over the past three and a half years.
“In order to develop product-service systems that are as holistic as possible, we have not only looked at the overall system level, but also the component and material level. Approaches such as reuse and recycling, closing product cycles and second-life uses were combined to develop concepts for the resource-efficient use of e-cargobikes over the entire life cycle,” explains Prof. Thomas Vietor, head of the Institute for Engineering Design at Technische Universität Braunschweig.
From exchangeable batteries to apps: More range and higher utilisation possible
The focus was particularly on the subsystems “business model”, “battery”, “app and service” and “recycling”. The aim was to increase the intensity of use on the one hand and to extend the usage period on the other. In order to measure the acceptance of the various measures in different pilot projects, the individual steps were supported by accompanying research. In the joint project, the researchers developed profiles and so-called user stories of possible users by means of the persona method to cover different user groups and, above all, different use cases. In the course of the project, customer- and user-oriented business cases such as private leasing, commercial leasing (e.g. by craft businesses), sharing, etc. were developed and compared with each other.
In order to make the e-cargobike accessible to as many private and public users as possible, the app “Circles Reallabor-DCE” was prototyped and finally implemented. This app makes it possible to significantly increase the utilisation of the cargo bike by allowing flexible booking every day around the clock. In order to also increase the range, the concept of a “secure charging cabinet” was developed together with Stöbich technology GmbH. According to the principle “exchange empty for fully charged”, users can exchange their batteries at specified locations and thus significantly increase the distance travelled per day.
Analysis of disposed battery systems
A lot of valuable raw materials are needed to manufacture lithium-ion batteries, but so far they have rarely been recycled. The researchers therefore also looked into the question of what concepts look like for recycling individual components or transferring them to secondary uses.
Disposed e-bike batteries could be collected via the project partner ElectroCycling GmbH. “In addition to the question of what condition the disposed battery systems were in, we were particularly interested in their structure. Non-destructive opening is the basic prerequisite for testing the removed cells individually and processing the battery system,” says Bastian Nolte, project manager and research assistant at the Institute for Engineering Design. The analysis of the old batteries showed that the individual cells could not be removed without destroying them. “This currently leads to entire battery systems being taken out of service because of individual, defective cells. This is neither sustainable nor cost-efficient,” says Nolte.
In their search for methods to remove defective cells from discarded batteries or to transfer the entire system to a secondary use, the researchers have developed two different prototypes of a battery system. In contrast to conventional battery systems, which are usually welded or glued, they use detachable connections and special mechanisms to remove cells from the battery system in a non-destructive manner. However, the two prototypes differ in terms of the number of used and new battery cells and dimensions.
In order to ensure comparable dimensions to OEM battery systems, defective cells must be replaced with new ones. Therefore, the researchers developed a second, larger prototype in which used cells could be utilised as replacements and assembled without major effort to achieve the capacity of batteries in first use. In this way, the researchers succeeded in significantly extending the service life of battery systems in the sense of the second-life approach.
About the LifeCycling² joint project
In addition to the Institute of Engineering Design at Technische Universität Braunschweig, the Institute of Social Sciences at TU Braunschweig with Prof. Dr. Dirk Konietzka, the Institute of Software Systems Engineering at TU Clausthal with Prof. Dr.-Ing. Andreas Rausch and the four industrial partners baron mobility service GmbH (Oldenburg), ceconsoft GmbH (Goslar), Stöbich technology GmbH (Goslar) and ElectroCycling GmbH (Goslar) are also involved in the research project. The project was funded over a period of three and a half years with a total sum of 2.5 million euros by the Federal Ministry of Education and Research (BMBF) in the framework programme FONA (Forschung für Nachhaltigkeit) through the funding measure ReziProK (Ressourceneffiziente Kreislaufwirtschaft – Innovative Product Cycles).