By Tom Jowitt
Scientists have come up with a potentially very useful development for parents to help make batteries safer if they are accidentally swallowed or ingested.
In the United States alone, it is estimated that nearly 4,000 children a year have to go to the hospital after swallowing the flat disc-like batteries commonly found in toys, watches, and other devices.
Hard to Swallow
Swallowing a battery can be potentially life threatening, as it can cause severe internal burns, damage to esophagus, tears in the digestive tract, and in some cases, even death.
If ingested, batteries interact with water or saliva, which then produces hydroxide, a caustic ion that damages tissue.
But now researchers at MIT, Brigham and Women's Hospital, and Massachusetts General Hospital have devised a new coating that prevents batteries from conducting electricity after being swallowed. When tested on animals, it found that such batteries did not damage the gastrointestinal (GI) tract at all.
"We are all very pleased that our studies have shown that these new batteries we created have the potential to greatly improve safety due to accidental ingestion for the thousands of patients every year who inadvertently swallow electric components in toys or other entities," said Robert Langer, the David H. Koch Institute Professor at MIT.
According to the researchers, roughly five billion button batteries are produced every year. To make matters worse, batteries are becoming even more powerful, which apparently makes them even more dangerous if swallowed.
The researchers took action over the issue because whilst there are regulations surrounding how batteries are stored in toys, package labels, etc., there were no technological innovations to make the batteries themselves safer.
"Disc batteries in the esophagus require [emergency] endoscopic removal," said Giovanni Traverso, a research fellow at the Koch Institute and a gastroenterologist. "This represents a gastrointestinal emergency, given that tissue damage starts as soon as the battery is in contact with the tissue, generating an electric current [and] leading to a chemical burn."
Researchers quickly realized that batteries generate a current when they are in their housing, because they are under a gentle pressure. Thus they developed a coating that would still allow batteries to conduct when under pressure, but that would act as an insulator when the batteries are not being compressed.
They opted for quantum tunneling composite (QTC), an off-the-shelf material commonly used in computer keyboards and touch screens. QTC is a rubberlike material, usually made of silicone, embedded with metal particles.
Batteries are of course highly toxic items full of nasty chemicals, but last year scientists from the University of East Anglia claimed to have made a significant discovery which they said could lead to efficient generation of clean electricity from bacteria.
They found that just by lying on the surface of a metal or mineral, bacteria can transfer electrical charge through their cell membranes, meaning they could be used, if hooked up to electrodes, as "microbial fuel cells," otherwise known as bio-batteries.