Internal temperature prediction of Lithium-ion cell using differential voltage technique

The performance of a Lithium-ion cell is strongly dependent on cell operating temperature. However, the measured temperature is often obtained from thermocouples attached to the surface of the cell. These measurements may not be representative of the internal temperature of the cell especially for lower ambient temperatures and high C-rates. A novel method utilizing differential voltage to predict the internal temperature of a 40 Ah Lithium-ion pouch cell is proposed. The difference between internal and measured external temperatures depends upon the C-rate and ambient temperature. For a continuous-rate discharge, the difference, between surface and measured temperatures, rises at beginning of discharge before peaking in the middle region and reducing towards the end-of-discharge. The outcome of this study could positively support control strategies within a battery management system (BMS).