In this paper, we perform 3D CFD simulations to understand the thermal operation of a High Breaking Capacity (H.B.C.) electric fuse within a Li-ion battery pack. The main focus is on evaluating the thermal behavior of a commercially available H.B.C. fuse containing four notched silver fuse elements through a numerical and experimental study that investigates the effect of the magnitude of electric current. For the numerical analysis we perform time-accurate, conjugate heat transfer-based 3D CFD simulations on high spatial resolution grids with commercial CFD software STAR-CCM+. Specifically, we utilize an electrodynamic potential model to calculate current density and the corresponding Ohmic heat generation of the fuse. The results of the numerical simulations with temperature dependent fuse material properties are validated against the experimental temperature measurements. The spatial distribution of temperature, and current in the fuse and its connected components are also compared for various input current values to evaluate the thermal performance of the fuse under a range of operating conditions.