Thermal Imaging of a Li-Ion Battery for the Estimation of the Thermal Parameters and Instantaneous Heat Dissipated

The electrochemical performance of a lithium-ion

battery is strongly affected by the temperature.

During charge and discharge cycles, batteries are

subjected to an increment of temperature that can accelerate

aging and loss of efficiency if critical values are reached.

Knowing the thermal parameters that affect the heat

exchange between the battery surface and the surrounding

environment (air, cooling fins, plates, etc.) is fundamental

to their thermal management. In this work, thermal imaging

is applied to a laminated lithium-polymers battery as a noninvasive

temperature-indication method. Measurements are

taken during the discharge phase and the following cooling

down until the battery reaches the ambient temperature.

The 2d images are used to analyze the homogeneity of the

temperature distribution on the battery surface. Then, experimental

results are coupled with mathematical correlations.

The derivation of the instantaneous heat generated in the

battery and Newton's cooling law in transient conditions are

used to estimate two main thermal parameters, as the

convective heat transfer coefficient and the specific heat

capacity, and then to calculate the heat generated by the

battery. The experimentally-based derivation of the abovementioned

thermal parameters will be useful in advanced

thermal models for the design of batteries and battery

cooling systems.