Title: Preventing thermal run-away using shape memory alloy
Rini Reginald, Ashish Chauhan, Saswat Rout, Venkatesh Muthukrishnan
Mercedes-Benz Research and Development, India
Key words: Thermal Runaway, Active and Passive Safety, Shape Memory Alloy, Nitinol, Literature Survey, Structural Simulation
Abstract
The present disclosure pertains to advancements in battery modules for electric vehicles (EVs). Addressing the critical issue of thermal runaway in high-voltage battery packs, this invention introduces a novel battery module designed to enhance safety of the vehicle. The battery module comprises a plurality of battery cells housed within an enclosure, electrically connected to the vehicle's circuit via busbars and innovative connectors made of Shape Memory Alloy (SMA). These connectors are engineered to transition between two states: a first state where they facilitate electrical coupling and a second state where they isolate the battery cells upon detecting temperatures exceeding a predefined threshold. This mechanism ensures rapid response to prevent thermal runaway, thereby mitigating fire risks and enhancing passenger safety. Additionally, the module includes a cell monitoring system that alerts users and service engineers to temperature anomalies and battery isolation events, ensuring timely maintenance and intervention. This configuration is easily implementable and retrofittable into existing battery systems, offering a robust solution to the challenges posed by prolonged vehicle electrification.
Methodology
Through literature survey it is observed, SMAs are metals that, even if they become deformed at below a given temperature (Martensite phase), they will return to their original shape before deformation (Austenite phase), just by being heated. Upon thermal propogation, the cell will pass on the heat to the SMA, making it deform, inturn disconnecting the charging circuit.
Conclusion
The innovative battery module with SMA connectors effectively prevents thermal runaway, enhancing EV safety and offering a cost-effective solution for existing systems, ensuring timely maintenance and intervention.