Non‐Destructive Monitoring of Internal Temperature Distribution in Prismatic Li‐Ion Battery Cells with Ultrasound Tomography

Abstract Large prismatic cells are increasingly being used as the primary power source in transportation applications. Effective online thermal management of these cells is crucial for ensuring safety and maximizing performance. However, significant discrepancies between surface and internal temperatures make it difficult to detect internal thermal anomalies promptly, which hinders effective thermal management and increases the risk of irreversible thermal hazards. This paper introduces an innovative technology for thermal management in prismatic Li‐ion batteries. By exploiting the temperature sensitivity of ultrasound velocity and applying tomographic reconstruction based on surrounding measurements, the technology enables detailed cross‐sectional thermal imaging. This allows for non‐destructive, real‐time visualization of internal temperatures. Furthermore, with its compact design and cost‐effectiveness, this technology is suitable for in‐situ deployment, offering a precise feedback mechanism for online thermal management. Demonstrations conducted during continuous discharging scenarios have shown that the system can identify high‐temperature regions near the tabs that remain undetected by surface thermocouples. This advancement has the potential to significantly reduce the risk of fires or explosions while enhancing battery performance in electric vehicles and other applications involving battery cells.