Table of Contents

Harvesting Lithium Ion cells from Tool Battery Packs

WIP do not use

Warnings

Lithium Ion cells may catch fire if punctured, heated or short circuited

Lithium Ion cells may explode if over heated due to another neighboring cell being on fire, or due to heat generated due to a short circuit

Lithium Ion cells on fire may release a toxic gas, Hydrofluoric acid, which can enter the body either through contact with the skin or inhalation. Hydrofluoric acid is colourless and causes deep burns when in contact with skin

Use eye protection

In Case of Fire

This section needs additional details and procedures

A Lithium Ion cell fire is notoriously difficult to put out and even if flames are not visible, the fire may still be going internally

Lithium Ion cells do not contain metallic Lithium. This means that it is safe (but not optimal) to use water to put out a Lithium Ion cell fire. Lithium Ion cell fires are of class “B” which means any “ABC” or “BC” fire extinguisher will work. Do not use a “D” rated fire extinguisher as those are meant to put out flammable metal fires.

  1. Place cell(s) on fire in a fire-proof container and take the container to a well ventilated area outside the building
  2. Using a fire extinguisher or water, put out the fire
  3. If you are not able to put the fire out, call 9-1-1
  4. Even if the fire is out, keep an eye on the batteries from a safe distance in case the fire restarts
  5. Report event to VHS BoD

Dangers of the Positive Terminal

The 18650 cell positive terminal is an area of high risk for external short circuits due to the proximity between the negative and positive terminals. When working near the positive terminal keep in mind the following:

In this picture you can see that the distance between the negative and positive terminals of the cell is less than 2 mm

Red → positive terminal

Green → insulating plastic washer

Blue → negative terminal
The battery pack manufacturers include a layer of non-conducting cardboard between the cell and the inter-connecting strips

In the second picture you can see how a light amount of pressure caused a short circuit that melted some of the insulating plastic away. This could have welded the tool to the cell causing the short circuit to over-heat the cell and trigger a fire or explosion

Tools

Procedure

Using a #10 Torx screw driver remove four screws from bottom of battery pack and remove cover and spring
Cut six wires at the solder points marked with X, then lift and remove connector from battery pack

The connector has an easy to use, self-contained, battery level indicator
Using Lineman's pliers grab the battery carrier by the plastic ridge and pull it straight out of the battery case
Remove padding foam from end of battery pack

Note picture indicating cell terminal polarities
Using the picture above as reference, mark the red lines on both cardboard sides

Green lines are given for reference only and they represent the metal strip that interconnects the cells

The red lines are meant to indicate where there is no connection between the metal strips
Steps are in process of being reviewed for increased safety

More to come
You will end up with five pairs of Lithium Ion cells that are still connected at the positive terminals
Due to the risk of short circuits when working near the positive terminals, for this step you will use your hands (preferably gloved to protect them from sharp edges on the metal strips)

Using your thumbs as lever points, pull the cells away from the metal strips
Using the needle-nose pliers, grab onto any parts of the metal strip that are still attached to the cell and using your thumb as a lever point (Do not use the cell for leverage as you could damage the plastic insulation and cause a short-circuit) pull the remaining metal away from the cells

Once done, cover the positive terminal with some tape to prevent accidental short circuits