The tiny button batteries that light up flameless “tea candles” pose a significant risk to children when swallowed. These lithium batteries, which are commonly used in these candles, account for 14% of all the button batteries swallowed by children during the last two years. Button batteries have higher voltage than other batteries, and they can cause severe burns in the esophagus if they become lodged there. Experts recommend that parents make sure battery compartments are shut on all devices that use batteries. They also recommend choosing devices that have screws to secure the battery compartment or using strong tape to make batteries difficult to access.
National Capital Poison Center, January 2017