Publication Date: 2012-Feb-21
The IP.com Prior Art Database
Many devices of varying sizes, shapes and capabilities use batteries as a power source. There are occasions (sometimes involving Lithium-ion/polymer batteries but sometimes involving other kinds of batteries) in which the battery overheats, smokes or catches fire.
There are many potential causes of overheating. Overheating can come from factors external to the battery, internal to the battery, or both.
In the case of Li-ion batteries (for example), there is a potential for serious failure (which may include explosion or fire) due to short circuits. Short circuits cause internal build-up of temperatures that reach a critical limit at which point the electrolyte decomposes and the whole cell cascades toward a thermal runaway situation. Most battery packs have some kind of electronic protection to protect against accidental short circuits, but this protection is of limited use (if not totally useless) if the short circuit is internal to the cell itself. This kind of internal short may be due to repeated mechanical shocks or drops, pinching, punctures etc.
As a general matter, bare cells ought to be (and many indeed are) able to withstand direct short circuits (e.g., where the battery terminals are shorted) without explosions or fires. The difference in the two cases (shorting the terminals and an accidental internal short) is that in the latter case, the conditions produce one or more localized short circuit points that allow the temperatures to reach a high (overheated) point over a small area. Once...