Ingestible Button Batteries

Technology #15945

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FIG 1. A new coated battery still conducts electricity when compressed, but not if accidentally ingested.  Illustration: Christine Daniloff/MITFIG 2. At left, a typical button battery; at right, a button battery coated with quantum tunneling composite (QTC).  Image: Bryan Laulicht
Professor Robert Langer
Department of Chemical Engineering, MIT
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Professor Jeff Karp
Harvard-MIT Division of Health Sciences and Technology, MIT
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Bryan Laulicht
Institute for Medical Engineering & Science, MIT
Janet Freilich
Harvard University
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Ben Rockney
MIT Technology Licensing Officer
Patent Protection

Safely ingestible batteries

US Patent Pending US 2016-0020436
Simple battery armor to protect against gastrointestinal injury from accidental ingestion
PNAS, (2014) Vol.111:46, pp. 16490-16495


Safer button batteries for use in consumer electronics and children’s toys

Problem Addressed

Every year in the United States, thousands of children accidently ingest button batteries.  In addition to children, an increasing number of seniors ingest button batteries after mistaking them for pills. Approximately 4,000 cases of emergency room visits from inadvertent battery ingestion are reported each year. Countless pets accidentally ingest them as well. 

Ingested batteries generate external electrolytic current and produce hydroxide ions which cause tissue damage.  Additionally, the short circuit current in conductive bodily fluids damages the battery gasket, releasing toxic metals such as cadmium, lead, mercury and lithium.  Once the batteries reach the stomach, corrosive and conductive gastrointestinal fluids further facilitate the release of the harmful battery contents, which poses both the acute and long-term health risks associated with heavy metal ingestion

Most severe damage occurs when the battery is lodged in the esophagus due to its anatomy of several narrowing areas and weak peristalsis.  The resulting tissue damage leads to serious complications, such as vocal cord paralysis, esophageal strictures, esophageal perforation, tracheoesophageal fistula, aortoesophageal fistula, and possibly death.

Recognizing this mounting health concerns associated with the button battery ingestion, the Consumer Product Safety Improvement Act of 2008 and the Button Cell Battery Safety Act of 2011 were implemented.  Although some progress has been made by these safety regulations, improving the safety of battery themselves has not been addressed.  Hence, in the hands of young children, ingestion of current button batteries remains a major health concern.


This invention presents a button battery coating consisting of a waterproof, pressure-sensitive quantum tunneling composite (QTC) that is non-conductive when immersed in conductive fluid environments but conducts when pressed upon by the electrode in a battery housing.

Standard button batteries in conductive fluids form electrolytic currents that cause tissue damage and breakdown of the gasket separating the anode and cathode.  Within hours of immersion, they begin to release the harmful contents.  In contrast, quantum tunneling composite coated (QTCC) button batteries show no signs of damage or current loss.  Immersion of QTCC button batteries in a simulated intestinal environment does not produce electrolysis and does not release the harmful battery contents.  Hence, these new batteries, when swallowed, prevent generation of an external current responsible for tissue injury and leakage of harmful battery contents. 

Electromechanical characterization demonstrates that QTCC button batteries remain sealed from contact with conductive bodily fluids and require approximately twice the pressure supplied by the adult esophagus and gastrointestinal tract to conduct.  QTCC button batteries should drastically lesson or even prevent the button battery from short circuiting after ingestion. 


  • Can power most battery-operated devices without modification of standard battery housings 
  • Markedly reduces the ingestion hazard of button batteries