Power bank have been designed to hold four battery(Li-ion 18650).
The power bank have one USB-A as output, and one USB-Micro-A as input (charging).
I have designed it for TP4056 module (with protection against too low battery discharging).
I have used one MT3608 to raise battery voltage to 5.1V.
I decided to not add any switch before MT3608 because, the module is consuming only 0.2mA while is no load on output.
Wall thickness was set to 2 mm.