Thermal safety management for vehicle battery systems
| Reference number | |
| Coordinator | Chalmers Tekniska Högskola AB - CHALMERS TEKNISKA HÖGSKOLA AKTIEBOLAG, Göteborg |
| Funding from Vinnova | SEK 5 700 000 |
| Project duration | September 2020 - August 2024 |
| Status | Completed |
| Venture | Bilateral call for proposals with China |
| Call | Research, development and innovation in the fields of life science, traffic safety and applied ICT - China collaboration |
Important results from the project
The objectives of this project were to develop methods to detect the root causes of a battery fire before it occurs, which would be a much cheaper solution than adapting vehicles to withstand thermal runaway of battery cells for a short time. In the project, we have developed physically based models that describe the phenomena that precede thermal runaway and what effects they have on temperature and the electrical signals of a battery pack, which are then used to create detection algorithms. Methods to adapt traffic to the detected risk have also been developed.
Expected long term effects
The results include simulation models for (i) intercalation of lithium ions in graphite to describe the growth of lithium dendrites causing internal short-circuiting; (ii) how voltages in a pack are affected when an internal short-circuit is about to occur, when an external short-circuit occurs, and contact problems; (iii) how local temperatures can be estimated from a few sensors in a battery pack, for TR detection. Furthermore, we have developed ways to avoid lithium plating during fast charging. Methods for controlling traffic flows at risk of TR have also been developed.
Approach and implementation
The project was organised with one work package for each cause of TR, i.e. cell internal short circuit, external short circuit, poor contact and overheating, a work package for traffic control in case of increased risk of TR and finally a work package for experimental validation. At Chalmers, the work was carried out by supervised postdocs and PhD students, and at Volvo Cars mainly by PhD staff. All the packages were carried out close to plan except the experimental validation where we did not get access to data from BIT as promised. However, the meetings with BIT were fruitful.