Why Do Smartphones Explode & Also Release Harmful Gases

Highlights

• Potential risks related to battery overheating and exploding have led manufacturers to recall devices
• Lithium-ion batteries in smartphones emit more than 100 fatal gases including carbon monoxide (CO)
• Carbon monoxide causes strong irritation to the skin, eyes, and nasal passages

In the new study, the researchers investigated a type of rechargeable battery, known as a “lithium-ion” battery, which is placed in two billion consumer devices every year like smartphones and tablets. Why do these batteries explode and risk lives of consumers. The answer lies in the fact that we as consumers are demanding better, bigger and faster devices and the manufacturers in all their eagerness are making compromises and stretching the limits of safety. It is like stretching a rubber band till it breaks. 

How Do Lithium Batteries Work?

Lithium is a light material and hence a popular material for manufacturing the batteries. A battery consists of two electrodes called cathode and another called anode. When we charge the battery the lithium ions move from the cathode to the anode and when the battery is in use, the lithium ion moves from anode to cathode. In between the electrodes are chemicals called electrolytes that help the charged ions move more easily between the two sides. The anode and cathode are separated by inert material called separators.

Why Do Lithium Batteries Get Heated Up and Catch Fire?

The lithium batteries get heated up and sometimes catch fire due to the following reasons:

• Using and Charging cell phone at the same time - When the cell phone is being used at the same time as it is being charged, there is two simultaneous movement of the charge and this produces more heat.
• Flawed separators - Letting the cathode and anode touch each other – this is what happened with to some of the Samsung Galaxy Note 7, leading it to go up in flames.
• Thermal runaway phenomenon - Can also lead to heating up and combustion. The electrolyte medium for quick ion movement between the electrodes aren’t very stable. Two way movement of charge or touching of electrodes or environmental heat itself can lead to extreme instability and a lot of heat. This also produces toxic gases that further heats it up. This creates a thermal runaway phenomenon when too much heat in one area of the battery can end in a fire.
• Making batteries store more power by increasing the voltage – Competition leads companies to pack more and more power in the batteries. Increasing voltage increases batteries’ power. To increase the power, manufacturer will add elements like nickel to the lithium. But increase in the voltage makes the electrolyte more unstable and makes them catch fire.

Almost 20,000 lithium-ion batteries were heated to the point of combustion in the study, causing most devices to explode and all to emit a range of toxic gases. Batteries can be exposed to such temperature extremes in the real world, for example, if the battery overheats or is damaged in some way

Why Do the Lithium Batteries Produce Toxic Gases?

Dozens of dangerous gases are produced by lithium batteries. The research, published in Nano Energy, identified more than 100 toxic gases released by the batteries, including carbon monoxide.

Dr. Sun and her colleagues identified several factors that can cause an increase in the concentration of the toxic gases emitted. A fully charged battery will release more toxic gases than a battery with 50 percent charge, for example.

The chemicals contained in the batteries and their capacity to release charge also affected the concentrations and types of toxic gases released.

Identifying the gases produced and the reasons for their emission gives manufacturers a better understanding of how to reduce toxic emissions and protect the wider public, as lithium-ion batteries are used in a wide range of environments.

“Such dangerous substances, in particular 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 compartment,” Dr. Sun said.

The researchers now plan to develop this detection technique to improve the safety of lithium-ion batteries so they can be used to power the electric vehicles of the future safely.

"We hope this research will allow the lithium-ion battery industry and electric vehicle sector to continue to expand and develop with a greater understanding of the potential hazards and ways to combat these issues,” Sun concluded.

“Nowadays, lithium-ion batteries are being actively promoted by many governments all over the world as a viable energy solution to power everything from electric vehicles to mobile devices. The lithium-ion battery is used by millions of families, so it is imperative that the general public understand the risks behind this energy source,” explained Dr. Jie Sun, lead author and professor at the Institute of NBC Defence.

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The gases are potentially fatal, they can cause strong irritations to the skin, eyes and nasal passages, and harm the wider environment. The researchers behind the study, from the Institute of NBC Defence and Tsinghua University in China, say many people may be unaware of the dangers of overheating, damaging or using a disreputable charger for their rechargeable devices.

Recall of Lithium Batteries

The dangers of exploding batteries have led manufacturers to recall millions of devices: Dell recalled four million laptops in 2006 and millions of Samsung Galaxy Note 7 devices were recalled this month after reports of battery fires. But the threats posed by toxic gas emissions and the source of these emissions are not well understood.

How to Prevent your Smartphone from Catching Fire

• Don’t use the device while it’s charging.
• Don’t expose device to direct sunlight. Stop charging it the phone becomes too hot
• Don’t overcharge your device
• Don’t use a phone cover while charging
• Don’t fully charge your device. Charge in short bursts. 
• Don’t charge near petrol pumps or when aircraft is refuelling
• Use low voltage charging like via a computer’s USB port.
• Charge in a well-ventilated area or in an Air-conditioned area.
• Direct an AC vent towards the phone when charging in a car.
• Use first-party chargers – Check the optimal recommended voltage and current for your phone. If you’re using USB Type-C port or Quick Charge - stick with the cable that came in the box.

Reference:

1. "Toxicity, a serious concern of thermal runaway from commercial Li-ion battery," by Jie Sun, Jigang Li, Tian Zhou, Kai Yang, Shouping Wei, Na Tang, Nannan Dang, Hong Li, Xinping Qiu and Liquan Chen.

Source-Medindia