<p>In this paper, the peak current optimisation of DAB converter under double phase-shift modulation is investigated to address the problem of accelerated battery aging due to high current stress in DC microgrid energy storage system. Firstly, the commutation process and operating characteristics of the DAB converter under double phase shift modulation are analysed. Then, in order to reduce the current stress when the voltage mismatch occurs, this paper takes the peak current expression as the objective function, uses the KKT condition to construct the mathematical model, and solves the optimal shift ratio for eight operating modes under double phase shift modulation. The optimal shift ratios are substituted into the boundary conditions of the corresponding feasible domains to derive the locally optimal power transfer range of the current stress. By analysing the current stress relationship in different feasible domains, a current stress optimisation strategy for adaptive ZVS mode is proposed to ensure the optimal current stress in the full power range. Finally, it is experimentally verified that the adaptive ZVS mode modulation has less current stress compared with SPS modulation and full ZVS mode modulation during voltage mismatch operation.</p>