Today's challenge centers around a product you probably have in your house right now:  AA and AAA one-time use batteries (i.e. primary alkaline cells).  We want to improve the reliability of primary alkaline batteries when they are exposed to situations that would cause a rapid increase in their internal temperature.  For example, imagine you are putting two AA batteries into a device, but you insert them both backwards.  This incorrect installation creates a condition that can raise the internal temperature of the battery (i.e. short circuit).

To increase reliability and assure proper usage, it's important for commercial batteries to have methods in place that will reduce or shutdown the power output in the event of a direct short.  We are seeking new methods and technologies that will effect such power reduction / shutdown under the following conditions:

• The reduction / shutdown mechanism initiates when internal temp is above 80 degrees C / 176 degrees F (i.e. it should not add resistance or affect the battery during normal usage below this threshold)
• The mechanism initiates well below 110 degrees C / 230 degrees F (i.e. it will initiate before internal temps reach this threshold)
• The mechanism may be reversible or permanent
• The mechanism must exist inside the cell, and may either be a device or a chemical modification