Current research on this topic is still in its infancy. Future developments look into multi-sensing approaches compatible with the battery environment that ideally can be integrated into existing battery components. By measuring various relevant parameters (including temperature, volume expansion, intercalation strain, cell pressure and other optical and acoustic parameters) that are linked to the degradation mechanisms (such as dendritic growth, metals dissolution and interface dynamics) the state of the entire battery and its components can be deducted.

Special focus will be on the miniaturisation and integration of these stable sensing technologies in a cost-effective way, compatible with the current manufacturing processes. Finally, efficient communication between the BMS and the sensors needs to be established, which will act upon the readings. Approaches currently being investigated are wireless sensors, which don’t add to the weight but add the wireless communication redundancy, or optic fibre cabling, which adds to the weight slightly, but typically has higher reliability.

Self-healing materials can be intrinsically self-healing, meaning the material itself recombines networks through reversible chemical bonds, or extrinsic, where the self-healing capability depends on healing agents such as pre-embedded microcapsules into the material.

Current research is looking into both autonomous (automatic activation of self-healing capabilities) and non-autonomous or on-demand self-healing functionalities (activation of self-healing capabilities through external trigger from the BMS). The implementation of these self-healing functionalities in the battery can be achieved in multiple ways:

• Modifying existing electrodes or separators to accommodate microcapsules that include self-healing additives e.g. using surface grafting.
• Developing new electrodes and separators with elements that provide inherent self-healing functionalities
• Developing protective layers or coatings for electrodes or separators that contain self-healing functionalities.
• Development of new electrolytes incorporating self-healing functionalities e.g. using glyme and ionic liquid-based electrolytes