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Guidance on the safe use, handling, storage and disposal of
Lithium Polymer batteries
It is strongly recommended that before charging and/or using a Lithium polymer battery, you should read and follow this guidance. Failure to do so may result in a fire, leading potentially to personal injury and damage to, or loss of, assets.
1. General safety instructions and warnings
1.1. When charging, only use a Lithium Polymer battery charger. Do not use a Nickel Metal Hydride or Nickel Cadmium charger. Failure to do so may a cause fire.
1.2. Never charge batteries unattended. When charging Lithium Polymer batteries you should always observe and monitor the charging process so that you can react to potential problems that may occur.
1.3. Some Lithium Polymer chargers on the market may have technical deficiencies that may cause the Lithium Polymer batteries to be charged incorrectly or at an improper rate. It is the users responsibility to ensure that the charger works properly and is PAT tested. Always monitor the charging process to ensure batteries are being charged properly. Failure to do so may result in fire.
1.4. If at any time you witness a battery starting to balloon or swell up, discontinue the charging process immediately, disconnect the battery, remove it to a safe area and leave it, preferably under observation, for approximately 15 minutes. This swelling may cause the battery to leak, and the reaction with air may cause the chemicals to ignite, resulting in a fire.
1.5. Since delayed chemical reaction can occur, it is best to continue to observe the battery as a precaution. This should only be undertaken in a safe area outside of any building or vehicle and away from any combustible material.
1.6. Wire lead shorts can cause fires. If you accidentally short the wires, the battery must be placed in a safe area for observation for approximately 15 minutes. Additionally, if a short occurs and contact is made with metal (such as a ring on a finger), severe injuries may occur due to the conductibility of electric current.
1.7. If for any reason you need to cut the terminal wires, it will be necessary to cut each wire separately, ensuring the wires do not touch each other causing a short, potentially causing a fire.
1.8. Always ensure that appropriate fire fighting equipment is available and close to hand in the battery charging area or in the place where damaged or swollen batteries are placed for observation. (For further advice on fire safety issues, contact the University Fire Officer on 2182).
1.9.Lithium Polymer batteries are volatile and can react to extremes of temperature. Never store, transport or charge battery packs inside your car in extreme temperatures, since these can cause a battery to ignite.
2. Charging Process
2.1. Never leave batteries charging unattended.
2.2. Charge in an isolated area, appropriately signed and away from other flammable materials.
2.3. Let the battery cool down to ambient temperature before charging.
2.4. Do not charge battery packs in series. Charge each battery pack individually. Failure to do so may result in incorrect battery recognition and charging functions. Overcharging may occur and a fire may result.
2.5. When selecting the cell count or voltage for charging purposes, select the cell count and voltage as it appears on the battery label. As a safety precaution, please confirm the information printed on the battery is correct.
a. Example: The label on a 2-Cell battery pack in series will read – “Charge as 2-Cell (7.4V), or may cause fire” – You must select 2-Cell for charging.
b. Example: The label on a 3-Cell battery pack in series will read – “Charge as 3-Cell (11.1V), or may cause fire” – You must select 3-Cell for charging.
2.6. Selecting a cell count other than the one printed on the battery (always confirm label is correct), can cause a fire.
2.7. You must check the pack voltage before charging. Do not attempt to charge any pack if open voltage per cell is less than 3.3v Examples:
a. Do not charge a 2-cell pack if below 6.6v
b. Do not charge a 3 cell pack if below 9.9v
2.8. You must select the charge rate current that does not exceed 1C (one times the capacity of the battery). A higher setting may cause a fire. The examples below are calculated at 1 x capacity of pack.
Examples:
a. 730 mAh: charge below 730 mA
b. 860 mAh: charge below 860 mA
c. 1320 mAh: charge below 1.32 Amps
d. 2100 mAh: charge below 2.1 Amps
e. 8000 mAh: charge below 8 Amps
First Discharge: Keep to 6 minute sessions with 15 minute breaks.
3.Storage & Transportation
3.1. Store batteries at room temperature between 40 and 80 degrees F, (4 and 27 degrees C)for best results.
3.2. Do not expose battery packs to direct sunlight (heat) for extended periods.
3.3. When transporting or temporarily storing in a vehicle, the temperature range should be greater than 20 degrees F, (-7 degrees C) but no more than 150 degrees F, (66 degrees C).
3.4. Storing batteries at temperatures greater than 170 degrees F, (77 degrees C) for extended periods of time (for more than 2 hours), may cause damage to the battery and possibly cause a fire.
4.Caring For Your Lithium Polymer Battery
4.1. Charge batteries using a good quality Lithium Polymer charger. A poor quality charger can be dangerous.
4.2. Make sure the voltage and current are set correctly, as failure to do so can cause a fire.
4.3. Please check cell voltage after the first charge.
Examples:
• 1-Cell: 4.2V (4.15 - 4.22)
• 2-Cell: 8.4V (8.32 - 8.44)
• 3-Cell: 12.6V (12.48 - 12.66)
• 4-Cell: 16.8V (16.64 - 16.88)
• 5-Cell: 18.5V (18.30 - 18.60)
4.4. Do not discharge the battery to a level below 3V per cell under load. Deep discharge below 3V per cell can deteriorate battery performance.
4.5. Use caution when handling lithium Polymer batteries to avoid puncturing the cells as this may cause a fire.
Operating Temperature:
• Charge:
• 32 - 113 degrees F (0 - 45 degrees C)
• Let the battery cool down to an ambient temperature before charging.
• Discharge:
• 32 - 140 degrees F (0 - 60 degrees C)
• During discharge and handling of batteries, do not exceed 160 degrees F (71 degrees C).
• Battery Life
• Batteries that lose 20% of their capacity must be removed from service and disposed of
properly.
• Discharge the battery to 3V/Cell, making sure output wires are insulated, then wrap the battery in a bag for disposal.
5. Safe disposal of Lithium Polymer batteries
Lithium Polymer batteries are used in a wide variety of both scientific equipment and personal electrical equipment. There are several types of Lithium batteries but they are all high energy power sources and all are potentially hazardous.
For safety reasons, it’s best that Lithium Polymer cells be fully discharged before disposal. However, if physically damaged, it is NOT recommended to discharge Lithium Polymer cells before disposal, (see below for details). The batteries must also be cool before proceeding with disposal instructions. To dispose of Lithium Polymer cells and packs the instructions below should be followed:- 5.1. If any Lithium Polymer cell in the pack has been physically damaged, resulting in a swollen cell or a split or tear in a cell’s foil covering, do NOT discharge the battery. Go to Step 5.5.
5.2. Place the Lithium Polymer battery in a fireproof container or bucket of sand.
5.3. Connect the battery to a Lithium Polymer discharger. Set the discharge cut-off voltage to the lowest possible value. Set the discharge current to a C/10 value, with “C” being the capacity rating of the pack. For example, the “1C” rating for a 1200mAh battery is 1.2A, and that battery’s C/10 current value is (1.2A / 10) 0.12A or 120mA. Or, a simple resistive type of discharge load can be used, such as a power resistor or set of light bulbs as long as the discharge current doesn’t exceed the C/10 value and cause an overheating condition. For Lithium Polymer packs rated at 7.4V and 11.1V, connect a 150 ohm resistor with a power rating of 2 watts to the pack’s positive and negative terminals to safely discharge the battery. It’s also possible to discharge the battery by connecting it to an ESC/motor system and allowing the motor to run indefinitely until no power remains to further cause the system to function.
5.4. Discharge the battery until its voltage reaches 1.0V per cell or lower. For resistive load type discharges, discharge the battery for up to 24 hours.
5.5. Submerge the battery into a bucket or tub of salt water. This container should have a lid, but it does not need to be air-tight. Prepare a bucket or tub containing 3 to 5 gallons of cold water, and mix in 1/2 cup of salt per gallon of water. Drop the battery into the salt water. Allow the battery to remain in the tub of salt water for at least 2 weeks.
5.6. Remove the Lithium Polymer battery from the salt water and dispose of as hazardous waste. (Contact the Chemistry Department on ext 4130). Written confirmation that the batteries have been fully discharged and soaked for the appropriate length of time, should accompany the batteries to the hazardous waste storage facility.
Health, Safety and Environment officeJune 2009

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