as mentioned here: How about 18650 Li-Ion battery pack over the Li-Po packs? , I was thinking to build a battery pack out of 18650 cells.
Since we need 48 Volts and the maximum discharge current is around 300A, I needed batteries that support this rather high discharge current. I found the LG 18650 HG2 cell that can handle 20A constant discharge per cell. To reach 300A I need to put 15 of them in parallel (15P).
To have 48Volts, I need to put 13 of them in series, that makes it a 13S15P Pack, a total of 195 cells with a capacity of 45Ah (3000 mAh per cell) total.
I am going to add plastic cell holders and a battery management system for charging and discharging. I will be spot welding the batteries with pure nickel strips.
This thread is to document the build.