Visualizing two-dimensional internal temperature distribution in cylindrical Li-ion cells

Temperature is one of the most important parameters in the safety issues of Li-ion batteries. Generally, the temperature distribution inside the cell is not uniform, and the observation and mechanism of the heat generation inside the batteries has not been fully understood. For well addressing this problem, here we have developed a new in-situ measurement setup to visualize the two-dimensional internal temperature field distribution of the internal cross-section in the cylindrical cells. Owing to the non-destructed advantage, this technology allows for well observing the 2D temperature field distribution at various discharge rates, which suggests the maximum temperature difference ~4.73 °C(3C rate) on the internal cross-section. The observation indicates the presence of remarkable temperature gradient inner the cylindrical cells, and such visualized inhomogeneous temperature features are more pronounced for fundamentally understanding heat generation and distribution. The technology opens a novel platform for acquiring solid evidence in studying the mechanism of thermal behaviors and designing safe Li-ion batteries.