This battery pack is made from a old battery pack and a old laptop battery.
Step 1: Extracting the Charger Circuit.
Get your old battery bank and pry it open to reveal the charger circuit.
If you do not have a battery bank on hand you can buy a battery bank from the dollar store for $3(like i did)
Step 2: Getting 18650 Cells
Get a old lithium ion laptop battery pack and pry it open, inside you would find some lithium ion cells.
if you do not have a old battery pack then you can order some 18650 cells online, be sure not to get a cheap cell as most of them are used or counterfit.
Step 3: Battery Cells
Hot glue the cells together. Then glue a stripped down wire onto one end of the battery. You can put any amount of cells you want, as commenters suggested leave the tabs on the battery
Step 4: Soldering
solder the wire into one end of the battery, then repeat the proccess for the other side
Step 5: Pcb
hot glue the pcb onto the battery, then solder positive to positive and negative to negative.
wrap electrical tape around the terminals and make sure the contacts don't touch.
Step 6: Finished
Wrap it in electrical tape and you are done.