fig2

Figure 2. HIs extraction of NASA-B005 battery data. (A) Discharge voltage versus time curve; (B) Charge voltage versus time; (C) Charge current versus time; (D) The extracted H1 represents discharge voltage decay duration; (E) H2 is charge voltage rise duration; (F) H3 represents constant-current charge duration; (G) show the Spearman correlation analysis diagram; (H) The CEEMDAN decomposition curves for the extracted H1 for NASA-B005, where h = 4 is sampling interval. HIs: Health indicators; HI: health indicator; NASA: National Aeronautics and Space Administration; CEEMDAN: complementary ensemble empirical mode decomposition with adaptive noise; IMF: intrinsic mode function.