Panasonic NCA Li-ion battery cells: the PTC switch

 

Left side: NCR18650PF and NCR18650B | Right side: NCR18650GA and NCR20700B

Unlike NCR18650PF and NCR18650B cells used in e-bikes, laptops, portable scientific or medical devices, the NCR18650GA and NCR20700B / NCR20700A haven’t built-in a PTC switch. Without this are truly bare-bones cells releasing all power for the drone!

Note: A PTC switch (positive temperature coefficient) adds internal resistance (Ω), thus reducing performance.

Inside cell view. Credit: NASA JPL

NCR18650GA
Panasonic NCR18650GA 10A
NCR18650B
Panasonic NCR18650B 6.7A