Sensing & Self-healing
The sensors developed in the B 2030+ projects are mainly embedded and have self-healing functionalities triggered via the BMS-system. It is particularly the detection of critical degradation electrochemical processes and chemical ageing one strives to measure. The sensors must also be capable of continuous, long-term operation and not interfere or interact with the battery.
Sensors by themselves are of no use – they must communicate with the surrounding, in this case the battery management system. To get a better hold of the internal conditions one needs to measure battery temperature, pressure, strain and some other parameters. Aspects of ease to manufacture and recycle must also be considered in the projects.
The self-healing mechanisms differs between the projects. It can be a thermally activated polymer network that support the re-binding of silicon nanoparticles. It can be removing manganese ions from the cathode that else would degrade the cell. It can also be things like mimicking natural healing mechanisms, and/or different methods to prevent dendrite growth.
Safety first
In line with this is also to develop safer materials for high-performing cells by targeted modification in cell components like the cathode, anode, separator and electrolyte. The higher the capacity of a battery cell, the more likely it is to burn. Strategies to avoid overheating can be some kind of doping, to apply more robust surface coating materials, to design high-capacity, high-voltage cathodes materials based on safer chemistries. For the anodes and electrode design the quest is to develop new stable non-swelling materials, high resistance to Li-dendrite formation. New electrolyte formulations with flame retardant properties and measurements to avoid over-charge and discharge is also part of building a broad electrochemical stability.