Current redistribution on hybrid power system combining supercapacitors with lithium-ion batteries for application of the electric drill

Hybrid power modules combining supercapacitors (SCs) with kinds of 18650 lithium-ion batteries (LIBs) for the electric drill is investigated. Specifically, homemade 18650 LIBs with silicon-based negative electrode denoted as 18650-CC-P is examined. Result reveals that in this hybrid power system, SCs recognized as the high power device effectively draw the larger part of current than LIBs recognized as the high energy device at the instant of start-up (23.4 ampere for SCs-P vs. 18.5 ampere for 18650-CC-P) for the electric drill. Compared to sole LIBs power system presenting about 34.9 ampere, hybrid SCs//LIBs power module demonstrates ability to redistribute current to improve impact of high discharging rate on LIBs, resulting in increasing durable usage of LIBs and potential advantage to implement of LIBs with higher capacity. Otherwise, an in-situ measurement platform is developed to examine state of modules for SCs and LIBs, including current distribution, voltage variation profile, resistance as operation of the electrical drill. Moreover, this platform could further evaluate rate capability of active materials upon on high discharging current for SCs and LIBs.