Monday, February 18, 2013

Lithium Ion Batteries: Fire Hazard For Airsoft?

Despite their light weight – and therefore high power-to-weight ratio are lithium ion / lithium polymer batteries too hazardous for Airsoft use? 

By: Ringo Bones 

With the recent incidents of lithium ion batteries catching fire in the Boeing 787 Dreamliners used by JAL and ANA that lead to their grounding and investigation by the Federal Aviation Administration, many have wondered whether the use of lithium ion / lithium iron phosphate / lithium polymer / Li-Poly storage batteries too hazardous for Airsoft. After all, the compartment in which the Li-Poly battery is stowed in most typical Airsoft AEG weapons systems is surrounded by flammable plastic and burning plastic can cause serious injuries once it drips into unprotected skin. 

Believe it or not, it was in the remote controlled model plane / model helicopter and Airsoft gaming world that the inherent fire hazard of Li-Poly batteries were first observed. These types of batteries can easily build up excess hydrogen gas under less than ideal charge and discharge conditions. The hydrogen gas can usually catch fire when exposed to stray electrical sparks – which there are no shortage of which in remote controlled modeling and Airsoft use. And given its inherent fire hazard, why are lithium ion / Li-Poly batteries still the preferred batteries of choice for Airsoft use? 

Fire hazard or not, the secret of lithium ion / Li-Poly batteries success over nickel cadmium and nickel metal hydride rechargeable batteries is that lithium ion batteries have a lower internal resistance making them have a better power-to-weight ratio compared to nickel cadmium and nickel metal hydride batteries of similar milliampere-hour rating. A typical Airsoft AEG gun upgraded to a much stiffer spring to make its BB pellet muzzle velocity greater won’t function with a fully-charged nickel cadmium or a nickel metal hydride battery rated at 1,600 mA-Hour. And yet a Li-poly battery rated at 1,600 mA-Hour 11.1 volt Li-Poly battery can drive the gun without problems.