With the wide application of the CLLC converters in bidirectional electric vehicle (EV) chargers, it becomes more important to improve their performance through proper parameter design. Compared with the frequency domain model, the time domain model can significantly improve the accuracy of converter design. However, the currently generalized operation mode analysis (OMA) method requires complicated operating mode judgment and solving systems of transcendental equations, which limits its practicality. To address this issue, a discrete event-driven piecewise analytic model (DEPAM) of CLLC converter is proposed in this paper. DEPAM obtains the transient and steady-state waveforms without the need for operating mode judgment and solving transcendental equations. Relying on DEPAM, a design methodology of the CLLC converter is introduced in this paper, which applies the lookup table method to the normalized parameters and achieves a complete traversal of all possible parameter combinations of the CLLC converter. This traversal considers gain range, soft-switching, capacitor voltage stress, and RMS current simultaneously. Finally, the design methodology is demonstrated through a 1 kW prototype with 98.8% peak efficiency.