The rise of electric vehicles will create millions of retired lithium-ion batteries, requiring fast diagnostics for second-life use. This work proposes a cost-effective electrochemical impedance spectroscopy (EIS) method that uses a broadband pseudo-random binary sequence (PRBS) and time-resolved frequency analysis, enabling module-level EIS measurements from 10 Hz down to 10 mHz with a standard battery cycler. An RMSE of 0.79% was achieved.