Most lithium ion batteries are safe, provided they come from a reputable source. Overall lithium-ion system is safe, providing certain precautions are met when charging and discharging. A review of the main safety issues is outlined.
Sony introduced the first lithium-ion battery in 1991 and overall the safety record has been good, certainly better than the predecessor rechargeable metallic lithium battery which was associated with safety concerns. A lithium-ion battery is a type of rechargeable battery in which lithium ions move from the negative electrode to the positive electrode during discharge and back when charging.
Any energy storage device carries a risk. With lithium ion batteries the most significant was in 2006 when a recall, by Sony, of almost six million lithium-ion packs occurred. This was due to the risk that microscopic metal particles could come into contact with other parts of the battery cell, leading to a short circuit within the cell.
There are several factors that can cause lithium ion batteries to failure, according to the U.K. standards organization UL. These are:
Lack or shortcoming of safety features.
Lack of stringent cell and battery manufacturing and quality control.
Mismatch of battery and charger performance capabilities. For example, the charger may fit your device, but may not be compatible with the battery. This practice may lead to overheating.
Device performance and environmental issues (temperature, vibration, shock, impact, and so on).
It is important to avoid crushing or bending a device and charger during use. Severe impact such as dropping a device and/or charger can damage any type of battery. The impact can affect a pre-existing flaw or it could create new damage by causing an internal short circuit
Another safety risk is with using electrical products in highly damp or humid environments, which presents an electrical shock hazard. This is particularly so for battery powered devices with or without an external charger.
There are also risks from counterfeit devices, which are especially prone to defects that could cause safety concerns. Purchasing batteries over the Internet from unknown sources, the advice runs, at exceptionally discounted prices is an indication the product may not be authentic.
