Li-ion Battery Pack Holder 21700-6S1P

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

INTRODUCTION:

This project aims to update and make existing battery container models more efficient. The redesigned supports allow power cables to be more securely attached to the nickel strips used to connect the Li-Ion cells. The structure is light 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; in the future, I will update designs for other pack configurations (e.g., 4S1P, 6S2P) and the other classic 18650 size. This is a basic support, requiring the use of tape and heat shrink to keep the pack intact. It also requires a fair familiarity with batteries, soldering, and wiring. Regarding the space for the strips, the groove is 2mm so a sandwich can be made without the strips protruding excessively from the holder.

AVAILABLE MODELS:

There are currently two models available:

1. 21700 Battery Pack type 6S1P - Hole 21.8 mm
2. 21700 Battery Pack type 6S1P - Hole 21.15 mm

21700 6S1P BATTERY PACK - 21.8MM HOLE:

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

Made of TPU, the model has precise tolerances and fits perfectly with Li-Ion “dummy” cells used for testing and practicing spot welding skills and 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 actual use with Reliance INR21700-RS50 cells, currently the best cells available with 5000mAh capacity and a discharge current of 70A. They are slightly narrower than the “dummy” cells, so I adapted the hole to them. I attach a link with the specifications:

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

DESIGN:

Arrangement of 21700 cell holders in Fusion360.

For modifying and designing the supports, I use Fusion360, a software that is very intuitive and easy for me to use. I don't have in-depth knowledge of the program yet, but I'll get there little by little. For what I usually do, it's more than enough :)

ASSEMBLY MATERIALS:

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 links to purchase them will follow soon:

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

                                                                                                           ⚠️ MOMENT OF CAUTION⚠️                                                                                                            

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