Safety tests of lithium 9-Volt batteries for navy applications

Commercial-off-the-shelf (COTS) batteries are relatively inexpensive, readily accessible, and extremely versatile. These attributes allow the military to save time and money during the research and development stages. Of these COTS batteries, a 9-Volt (9V) lithium/manganese dioxide battery is the subject of this paper. This 9V battery has the ability to provide a low magnetic signature, which is very important to the Navy for many applications. Also, it is Underwriters Laboratories (UL) listed at the unit level; however, these UL tests can not be directly related to the safety of these 9V batteries when they are combined in various series and parallel configurations. Naval Surface Warfare Center (NSWC) Carderock was tasked to rate the safety of several such specialized battery packs. It was found that packs consisting of two 9V batteries in parallel were relatively safe, experiencing no violent behavior. Battery packs with six 9Vs in parallel vented and deformed the 9V batteries, but no smoke or names were noticed. A battery pack with thirty 9V batteries, 2 in series with 15 legs, experienced venting, smoke and flames under certain circumstances. After testing, the six and thirty 9V packs were required to include the addition of various safety devices.