The recent controversy involving Samsung Galaxy Note 7 was a harbinger of the various hazards Lithium-ion (Li-Ion) batteries, used in billions of smartphones, can expose users to. Most of these Samsung phones started leaking out smoke and eventually caught fire, causing first degree burns to several users across the world. Samsung isn’t the first phone maker facing the battery issue. Nokia phones powered by Li-Ion battery started exploding in 2007, forcing the Finnish company to replace batteries in over 46 million devices. US based Dell had to recall some 4.1 million laptops in 2006 for similar reasons.
The risk of exposure to hazardous gases
A recent study carried out by researchers at NBC Defence and Tsinghua University, China claims that fire caused by overheating, damage or using a disreputable charger with Li-Ion battery can produce more than 100 toxic gases including carbon monoxide. The study was published in international journal Nano Energy Volume 27.
Researchers exposed two types of commercially used Li-Ion batteries to high temperature in a combustion chamber made of steel glass panel. A hole was created at the top to provide an outlet to the gases. A chemical identification system was used to separate and identify the gases that were released due to the combustion. Besides carbon monoxide, the researchers found traces of sulphur dioxide, naphthalene and propylene oxide in the fumes.
Researchers point out that in real life usage overheating or damage to Li-Ion batteries can expose it to such high temperatures.
It was also found that a fully charged battery is more likely to release more toxic gases compared to a battery with 50% charge. The capacity of a battery to release charge can also affect the concentrations and release more toxic gases. This means batteries with bigger capacity pose greater risk than smaller batteries.
Lead researcher Dr. Jie Sun said, “Dangerous gases such as Carbon Monoxide have the potential to cause serious harm within a short period of time if they leak inside a small, sealed environment, such as the interior of a car or an airplane.” Read more here.
The issue with Li-Ion batteries
Part of the problem lies with Li-Ion battery itself. The liquid inside a lithium ion battery is highly inflammable. Any damage to the outer layers of the battery can cause a short circuit which in turn can cause fire and explosion. While the Li-Ion technology is not the safest it is the most convenient and compact option available to phone manufacturers right now. A single charge lasts a day, while the usable life is 2 years or 1000 charge and discharge cycles.
Solar cells, Aluminium ion and Fuel Cells are some of the alternatives that have been considered by manufacturers. However, they have not been able to make them small enough so they can fit into a smartphone.
US company Apple is working on bringing fuel cells into mainstream. It applied for a patent for a portable Fuel Cell system from US Patent and Trademark office in March 2015 and was awarded the patent in September 2015. What has caught Apple’s attention is the ability of Fuel Cells to hold charges longer than Li-Ion batteries. A single charge is likely to last 4 to 5 days. It is also clean and more eco-friendly. It is widely used as APUs (Auxiliary Power Units) in electric cars, such as Toyota Prius. A Fuel Cell generates power through a chemical reaction involving hydrogen and oxygen
A British company Intelligent Energy is working on a Fuel Cell powered smartphone. In February 2016, it announced that its working with an OEM to develop an embedded hydrogen fuel call system that can keep a smartphone backed up for a week. However, initially it will co-exist with the smartphone’s Li-Ion battery.