Li ion batteries general and safety info.indd

LITHIUM-ION BATTERIES
could short-circuit against other items.
VITAL SAFETY/USAGE INFORMATION
9. Although environmentally friendly If you do need to dispose of your Li-ion type battery, discharge fully You MUST only use a charger designed to charge Lithium ion first. You can do this by the use of a light bulb, electric batteries. Never use a nicad or other charger as this is very 10. Keep battery packs away from children! Never attempt to charge at a rate faster than that recom- mended in the instructions. Check that the battery cell count
11. If you should get electrolyte from the cells on your skin, matches the charger cell count switch (if fitted).
wash thoroughly with soap and water. If in your eyes, rinse WARNING re CHARGING - Never charge unattended thoroughly with water. Seek medical assistance. Never leave you battery whilst charging in case of overheat- 12. Only use the recommended charger for Lithium-Ion batteries. WARNING re CHARGING - Use a safe surface/container If you use the wrong charger this will damage the cells and Charge only on non-flammable surfaces, e.g. concrete floor
preferably outdoors, or in a pyrex cooking dish with the bat- tery placed on a bed of sand, or in a fireplace. Never charge LITHIUM-ION BATTERIES
WARNING re CHARGING - Switch off if too hot IMPORTANT CHECKS BEFORE YOU CHARGE
If the battery becomes hot to the touch during charging, dis- 1. Before charging your battery check for any damage i.e. if WARNING re CHARGING - Extinguish fires with sand the battery has expanded or swollen in size and if the battery If something goes wrong and your battery catches fire, cells has been punctured even if this is the first time the always have sand from a fire bucket at hand to douse the battery is going to be charged. If any damage has occurred 2. Always re-check the settings on your charger before you start to charge to ensure you have the correct settings you must carefully inspect the battery for damage and dis- selected. Using the wrong settings can damage your battery card if damaged. Always observe the battery carefully for and in some cases can cause the cells to catch fire! at least 20 minutes after a crash. The pack may look fine
but a perforation or damaged wire means the pack must be 3. Never leave this battery unattended while charging and always place your battery on a non-flammable surface.
LITHIUM-ION BATTERIES
4. Monitor the heat of the battery while charging is in progress IMPORTANT USAGE/SAFETY INFORMATION
(every few min’s!!!). If the battery starts to get very hot quite quickly or has got very hot, stop charging and disconnect 1. Never discharge Li-ion/Li-poly batteries to below 3 volts the power to the charger and remove the battery from the per cell and never charge at greater than 4.2 volts per cell. This is very important as damage will occur if you discharge below 3V or charge above 4.2V and the battery may not re- 5. If your battery has been damaged in any way as listed above, dispose of the battery in the correct way. If the voltage does drop below 3V per cell and you can get your battery to take a charge it may not give its full capacity and deterioration in performance will occur. This will invali- LITHIUM ION - ADVANTAGES
Lithium ion batteries in model aircraft and helicopters can 2. It is recommended that you use a Voltmeter to monitor the give 15 minute to half hour flights where previously 5 to 10 condition of the cells. If you are unsure about this, seek minute flights using nickel cadmium (nicad) or Nickel metal professional advice from your model shop or flying club. hydride NiMH batteries had been the norm.
Lithium ion batteries (Li-ion) are therefore said to have a very 3. Use the correct E.S.C. (electronic speed controller) with your high ‘energy density’ compared with Nicad or NiMH batter- Li-Ion battery pack. This will help prevent your battery from ies – around 5-12 times, approximately.
dropping below 3v per cell and causing irreparable damage. The high energy density means that, for example, a Li-ion 4. Do not modify/change any part of this battery or lead. Do battery might weigh just a quarter of the weight of the same not remove its heat shrink protective covering. Removal or capacity nicad. You can see that small models that once flew modification may damage the battery and will invalidate any for just a few minutes last week can now fly for considerably 5. Do not place this battery near fires or anything with high As most people know, Cadmium is highly toxic and is known to accumulate in biological systems, which is why nicad bat- teries must be disposed of carefully and in the right place.
6. Do not charge batteries while you are driving and do not store batteries in any type of motor vehicle.
7. Do not let this battery get wet or become submerge in any 8. Do not carry loose batteries in your pocket or bag as they LITHIUM ION - DISADVANTAGES
The plusses for modellers come at the expense of the MUCH 2. More precise equipment and monitoring required A more rigorous approach plus a profound awareness of the difference between nicads and Li-ions is vital to the wellbe- ing and SAFETY of users, homes, bystanders and equipment.
Many of these points also apply to nicad/NiMH cells - it’s important to remember that these batteries too will explode Li-ions, however, have additional characteristics, of which See chemistry and energy density below.
LITHIUM ION - DIFFERENT FROM NICADS
Lithium ion batteries can hold between 5 and 12 times the energy - hence greater ‘energy density’ - than similar weight Nicad or NiMH batteries – i.e. a HUGE amount of energy!! Therefore, if a battery is accidentally short circuited, 5-12 times the energy of a nicad will try and escape from the battery AT ONCE!! – the battery may EXPLODE if not discon- Lithium ion batteries are unlike Nicad or Nimh batteries in that they hold FAR MORE energy than those batteries and Please re-read this if you are unclear about any of the above and you plan to use Li-ion batteries in you models.
2. Different chemistry to Nicads/NiMH’s Lithium reacts rapidly with oxygen, will burn skin and is If things go wrong inside a Li-ion battery, elemental Lithium can be deposited internally - and if the battery case be- comes ruptured – Lithium can be ejected from the battery! Further, elemental Lithium is highly reactive when exposed to water, producing flammable hydrogen gas and corrosive Please note that Li-ion batteries contain no elemental Lithi- um and that Lithium metal is only created when the battery goes seriously wrong. Make sure nothing goes wrong! 3. Charging and discharging Li-ions in model applications Were you told any of the above bits of info when you bought your Li-ion powered mobile phone and laptop computer? However, your phone and laptop are probably only ever charged at ‘low’ charge rates, and discharged at similarly ‘low’ discharge rates. Plus, they are most likely equipped with voltage and current regulators/monitors.
Very few model Li-ion cells are equipped with regulators/ On the discharge front, its a fact that most model flight ap- plications demand relatively high (and variable) discharge rates from Li-ion batteries, and worse still – modellers will often demand faster charge times and hence sometime over- You must use the right Li-ion charger and charge at the cor- rect rate. You MUST NOT OVERCHARGE or over-discharge Overcharging and over-discharging can be DISASTROUS. Li-ions could catch fire or explode if overcharged! Lithium ions are relatively new for the model community and do represent a potentially great future for electric modelling But only if used carefully and responsibly.
Copyright J Perkins Distribution 2003. All rights reserved. E&OE.

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