The widespread adoption of electric vehicles (EVs) hinges on the efficiency and reliability of their battery systems. However, EV batteries still have many issues, mostly in terms of quantity, storage efficacy, charging speed, lifespan, and security, particularly, temperature variations, which can cause accidents that can lead to losses of products and persons. Hence, any advancement in the field of EV batteries would improve their performance and thus, boost daily usage of EVs that would reduce the pollution caused by traditional cars. Therefore, the main objective of this study focuses on improving the thermal and mechanical stability, energy storage efficiency, and safety of electric vehicle batteries by incorporating multifunctional materials, particularly phase-change materials (PCM) and shape memory alloys (SMA). By incorporating PCM, the thermal regulation of batteries is enhanced, resulting in better charge-discharge cycles, extended battery life, and reduced overheating risks, all of which contribute to increased safety. SMA integration, on the other hand, offers mechanical protection, flexibility in heat management, and resilience against thermomechanical fatigue, further improving battery longevity. Moreover, the incorporation of these adaptive materials not only boosts battery performance but also ensures that the materials can be seamlessly integrated without affecting the overall design or significantly increasing the weight of the battery. Thus, a systematic numerical study was conducted in order to adapt the multifunctional materials with each other and with EV battery systems. The study demonstrated a significant improvement in battery thermomechanical stability, leading to better storage performance, quality, and charging speed. Particularly, the findings showed a remarkable increase around 23: % in thermal stability duration, preventing excessive temperature variations, and an important reduction in mechanical vibrations around 79 %, which minimizes fatigue and enhances durability. Finally, the results revealed that the proposed adaptable materials are the most stable for car batteries even during fast charging while driving. These materials can also support alternative ways of charging, such as using solar sources.