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I am designing battery charger and I want to know how to calculate max charging current for a lithium-ion battery pack. I am using Texas Instrument Chip bq24616 and their evaluation board.
Assumption: Battery pack has- 5 in parallel and 4 in series of 18650 batteries include onboard BMS.
Base on the datasheet of the battery:
Each cell is 3.7V 2500mA
Standard Charge current 500mA
Battery pack = 14.8v 20AH
Is that mean max charging current is 5 x500mA = 2.5A
Yes, according to KCL the charge current splits up into five equal partial currents when five cells are nearly identical and connected in a parallel manner. Therefore you should always create a battery pack consisting out of cells from the same batch.
Currently, you just mentioned only the standard or recommended charging current of the cell (in your case 0.2c), if you need to calculate max charging Current then you need to know the max charging current of the cells in parallel. then multiplication of the max charging current of each cell with the number of parallels will give the max charging current of the battery pack. Addition point to give attention to is that most Battery Management System (BMS) has "charge overcurrent protection" with a tolerance. so your max charging current is as well limited by the lower limit of charge overcurrent protection of your BMS.
