Every parent knows all too well how young kids like to try different things for taste. Small items, if swallowed, can often pass through without too much trouble, but some, like tablet batteries and multiple magnets, can cause more serious, even life threatening, troubles. Magnets can stick together, pinching gastrointestinal tissue, while small batteries will conduct and burn tissue, often causing serious perforations within the GI tract. While the fear of magnets has been dealt with in America by making them selectively illegal by decree, tablet batteries can now be made safer thanks to advancements in technology.
Researchers at MIT created a battery that only conducts when squeezed by those little metal blades that are usually found within the battery housing of devices that use them. If swallowed, the battery will be just a metal lump coming through, and considerably safer than a charged conventional battery. They even tested the new battery by having a pig swallow it, and the outcome was great, according to the pig.
Some details from MIT about how the new batteries work:
The research team began thinking about ways to alter batteries so they would not generate a current inside the human body but would still be able to power a device. They knew that when batteries are inside their housing, they experience a gentle pressure. To take advantage of this, they decided to coat the batteries with a material that would allow them to conduct when under pressure, but would act as an insulator when the batteries are not being compressed.
Quantum tunneling composite (QTC), an off-the-shelf material commonly used in computer keyboards and touch screens, fit the bill perfectly. QTC is a rubberlike material, usually made of silicone, embedded with metal particles. Under normal circumstances, these particles are too far apart to conduct an electric current. However, when squeezed, the particles come closer together and start conducting. This allows QTC to switch from an insulator to a conductor, depending on how much pressure it is under.
To verify that this coating would protect against tissue damage, the researchers first calculated how much pressure the battery would experience inside the digestive tract, where movements of the tract, known as peristalsis, help move food along. They calculated that even under the highest possible forces, found in patients with a rare disorder called “nutcracker esophagus,” the QTC-coated batteries would not conduct.
Study in Proceedings of the National Academy of Sciences: Simple battery armor to protect against gastrointestinal injury from accidental ingestion…
