Li-Ion 21700-6S2P Battery Pack Holder

LI-ION BATTERY PACK FOR FPV DRONES, RC AND ROBOTS

INTRODUCTION:

This project aims to update and make existing battery holder models more efficient. The supports I redesigned allow for a more secure attachment of power cables to the nickel strips used to connect the Li-Ion cells. The structure is lightweight yet very robust; thanks to tight tolerances, the batteries fit snugly and cannot rub against each other, ensuring proper spacing. The 3D model is currently based on 21700 cells. It's a basic holder, requiring the use of tape and heat shrink to keep the pack intact, and also requires decent familiarity with batteries, soldering, and wiring. Regarding space for the strips, the groove is 2mm so it's possible to make a sandwich without the strips protruding excessively from the holder.

AVAILABLE MODELS:

There are currently two models available:

1. 21700 Battery Pack type 6S2P - 21.8 mm Hole
2. 21700 Battery Pack type 6S2P - 21.15 mm Hole

21700 6S1P BATTERY PACK - 21.8MM HOLE:

The hole size refers to the diameter of the circumference that accommodates the battery.

Made of TPU, the model has precise tolerances, perfectly fitting "dummy" Li-Ion cells used for testing and training spot welding skills and for studying battery pack dimensions. I attach a link to the website with the cells in question:

https://www.nkon.nl/en/21700-empty-cell.html

21700 6S1P BATTERY PACK - 21.15MM HOLE:

The hole in this model is for real use with Reliance INR21700-RS50 cells, currently the best cells available with 5000mAh capacity and 70A discharge current. They are slightly narrower than the "dummy" cells, so I adapted the hole to them. I attach a link with the characteristics:

https://www.reliance-battery.com/en/products-solutions/products###

DESIGN:

Layout of 21700 cell holder in Fusion360.

For modifying and designing the holders, I use Fusion360, a software that is very intuitive and easy for me to use.

MATERIALS FOR ASSEMBLY:

Below is a list of the few materials needed to build the pack; for now, a simple list, a video tutorial and a list with purchase links will be available soon:

• Spot welder
• 0.15x10mm Pure Nickel or Nickel Plated Strip
• 10mm and 30mm Kapton Tape
• Automotive fabric tape
• Heat shrink sleeve to enclose the entire pack
• 12 AWG cable with XT60 connector
• 6S balancer cable
• Paper insulator for 21700 cells
• Patience and steady hand :)

                                                                                                           ⚠️ MOMENT OF ATTENTION⚠️                                                                                                            

Battery packs and the batteries themselves, especially Li-Ion cells, are not a toy. Make sure to follow the general usage rules for these products in a suitable location. The risk of fire is around the corner, equip yourselves accordingly and store the product as suggested by your cell manufacturer. It is good practice to keep them in a dry place away from combustibles, heat sources, and potential ignition sources. Assemble this at YOUR OWN RISK AND DANGER. Any responsibility for incorrect assembly is excluded.