Ricardo develops new model-based EV battery control technology; evaluating new cell chemistries
12 July 2017
Ricardo has developed a new Battery Management System (BMS) for EVs that is scalable to a wide range of applications. The new BMS enhances the use of advanced model-based control methods to optimize the performance of both existing and next-generation cell chemistries.
One of the most significant impediments to an increased market share for plug-in vehicles is the high cost of rechargeable energy storage. This can represent a very significant cost element of a typical battery electric vehicle (BEV); manufacturers need to strike a balance between product affordability and available range between recharges. For BEVs to break out of this paradigm it is likely to require the development and refinement of battery technologies based on entirely new, more affordable, and lighter weight cell chemistries than those used in today’s lithium-ion based battery packs.
To operate effectively, such new cell chemistries are also likely to require a more intensive level of model-based management and control than today’s technology, delivered through a much more sophisticated BMS, Ricardo notes.
Depending on the requirements of the battery pack and vehicle application on which it is deployed, the new Ricardo BMS provides a scalable increase in processing power from approximately 90 to 800 million instructions per second in comparison with its predecessor.
This increase in capacity enables the adoption of sophisticated model-based battery management and control enabling, for example, the BMS to estimate the state of the cells based on parameters that might be impractical or impossible to measure, such as instantaneous internal cell temperature.
The additional processing power and model-based capability of the new Ricardo BMS is particularly suited to the evaluation of new and innovative cell chemistries, where the careful monitoring and close control of every aspect of battery cell and pack performance can be essential for effective development and evaluation.
The new BMS was part-developed through, and deployed for the first time on, the Revolutionary Electric Vehicle Battery (REVB) project, which set out to evaluate a new Lithium-Sulfur cell technology developed by OXIS energy. The new cell and BMS are intended to achieve 400Wh/kg cell energy density with practical cycle life and performance metrics. This project was led by OXIS and part-funded by Innovate UK.
The results of Ricardo’s work on this project—including the design and manufacture of proof-of-concept battery module samples for testing and development—will be presented later this year at the CENEX Low Carbon Vehicle Event 2017.