Temperature Estimation of Lithium-Ion Battery Based on an Improved Magnetic Nanoparticle Thermometer

Lithium-ion batteries are widely used in new energy vehicles, especially electric vehicles. Temperature estimation is very important for battery life and safety. However, current temperature measurement methods cannot accurately measure the battery internal temperature. In this paper, a new method for battery temperature estimation based on an improved magnetic nanoparticle thermometer (MNPT) is proposed. The influence of dc magnetic field on temperature accuracy of a MNPT is firstly studied, the optimal dc magnetic field is found out under limitation of maximum temperature sensitivity and minimum temperature error, a new model of an improved MNPT is also established based on the ratio of first and second harmonics, and then the Lithium-ion battery temperature is estimated by use of the improved MNPT, the simulation and experiment results show that the improved MNPT can accurately estimate the battery internal temperature, which provides a new method for monitoring battery temperature of a new energy vehicle.