Many works [2][3] make use of high frequency battery models and Printed Circuit Board (PCB) models for EMC emission characterization. This work proposes those models in addition to a Battery Management System (BMS) impedance to show the effect on the noise received by the BMS under Direct Power Injection (DPI) simulations with different external components configurations. Furthermore, in order to ease some of the first design stages of the BMS and its external components, a straightforward analytical model to estimate the noise levels and its maximum coupling frequencies during DPI simulations is also elaborated and validated by simulations.