All the power banks I’ve disassembled had all of the cells in parallel, and a single small PCB that has both the buck charging circuit to get down to 4.2V, and the boost output circuit to get ...

According to India Dry Cell Battery & Flashlight Market Outlook, 2021, The dry cell market constituted a cumulative growth of 12.72% in the period of five years from 2010 to 2015.