The Ins and Outs of Lithium-ion Batteries
Rechargeable lithium-ion (Li-ion) batteries are used to power many portable electronic devices, including barcode scanners, mobile computers and smart phones. Li-ion batteries are renowned for their high energy density, minimal memory effect and slow self-discharge.
How do they work?
Lithium-ion (Li-ion) batteries are comprised of two electrodes (one negative, one positive) and an electrolyte that acts as the electrical conduit between the electrodes. When a lithium-ion battery discharges, lithium ions transfer from the negative to the positive electrode (the opposite occurs when the battery is recharging).
Advantages of Li-ion batteries
- Higher energy density - Li-ion batteries pack more “punch” than other rechargeable batteries, making them lighter and smaller.
- Minimal memory effect – Li-ion batteries seldom lose their “maximum energy capacity” over the course of their life (even if they’re frequently recharged following partial discharge).
- Low self-discharge rate – When not in use, Li-ion batteries don’t self-discharge as quickly as NiCd and NiMH batteries.
- Faster charging – Li-ion batteries charge faster than other rechargeable batteries.
- Longevity – Good-quality Li-ion batteries should provide between 400 and 1,200 complete charge/discharge cycles – provided they’re maintained properly.
Tips for maintaining Li-ion batteries
- Ideally, Li-ion batteries should be stored and recharged at room temperature (20-25 degrees Celsius).
- Use the right charger; in other words, the one supplied by the manufacturer. Non-genuine or generic chargers can potentially damage a Li-ion battery or the device it powers.
- Li-ion batteries are sensitive to heat, which can shorten battery life. Be careful not to overcharge or leave Li-ion batteries in the sun for too long.
- When it comes to long-term storage, Li-ion batteries should be partially charged (50% is a commonly-quoted level) and stored at room temperature to reduce the aging effect. Avoid storing Li-ion batteries in a fully charged or totally discharged state.
- Always recharge a fully-discharged Li-ion battery ASAP, as a prolonged “deep discharge” can kill the battery.
- Avoid dropping or rough-handling Li-ion batteries, as they can leak internally.
When should a Li-ion battery be replaced?
Put simply, a Li-ion battery should be replaced when its overall performance starts to drop. An end-of-life Li-ion battery typically loses its charge quickly, and warms up whilst recharging (a sign of high internal resistance and cell degradation). Given the potentially volatile nature of old Li-ion batteries, they should be disposed of quickly (MobileMuster – www.mobilemuster.com.au - provides a free recycling service).