Extended Data Fig. 9: Hyperparameter sensitivity analysis on a cycle life simulator.
From: Closed-loop optimization of fast-charging protocols for batteries with machine learning
The true cycle life of the best charging protocol as estimated by CLO, averaged over ten random seeds, is plotted as a function of the initial exploration constant (β0), the exploration decay factor (ε) and the kernel bandwidth (γ). The values of all other hyperparameters are consistent with the values indicated in the ‘BO hyperparameter optimization’ Methods section and in Supplementary Table 5. Overall, CLO achieves acceptable performance over a range of hyperparameter combinations; the highest-cycle-life protocols as estimated by the best and worst hyperparameter combinations differ by only 60 cycles. In our real-world CLO experiment, the selected hyperparameters are β0 = 5.0, ε = 0.5 and γ = 1; this combination performed well on a variety of simulated parameter spaces and budgets.
