Many DIY projects such as Robot, DIY Car, Drone need 18650 Rechargeable Li-ion battery. There are many reasons to use recycle 18650 battery instead of buying new one. Some of them are as following:
1) Discarded battery is extremely harmful to our environment. Reusing 18650 battery instead of throwing it into garbage can protect the Earth for our children.
2) 18650 battery has bigger power capacity and therefore much more expensive than regular AA or AAA rechargeable battery. Using free recycle battery can save you a lot of money.
3) Li-ion battery is dangerous to airline safety and therefore has very high shipping cost.
4)Laptop factories normally will use high quality 18650 batteries to make laptop working for long time. So recycled battery from laptop normally means bigger capacity and higher quality than those cheap batteries sold online.
The main recycle source of 18650 battery is from old laptops. Many cities have electronics recycle depot. You can go to these recycle depot and find wasted laptop. Some depot might put laptop battery bar into battery trash area. So if you find laptops there have no battery,you should check the battery trash area and collect the laptop battery bar.
Following instruction will guide you dismantle the battery bar and recycle 18650 battery step by step:
Material and tools: Hammer, Flat Head Screw Driver, Pliers and Garden Glove(to protect your hand from metal burr) and old laptop
Step 2)Remove the battery bar from laptop
Step 3)Break the battery bar with hammer,screw driver and pliers, then take out the batteries.
Don't forget to take the glove before removing the circuit metal burrs, otherwise your finger might be hurt.
Step 4)Distinguish the polarity of the battery as per following picture:
Step 5)Charge the battery with 18650 battery charger
Step 6)After the battery is fully charged, put the battery into your device and see if it works.
I use a Osoyoo Arduino Robot car ( http://osoyoo.com/2017/08/06/osoyoo-robot-car-diy-introduction/ ) to make the test. After the battery is installed in the car, my car voltage meter read as 8.4V, the car runs very well.
Congratulations! You have done great job to save our environment and your money.