Note the bright white flash, and light colored smoke. That is not a battery fire (don't ask how I know) The metal is magnesium http://www.hydro.com/en/about/history/1946_1977/1
Despite Hydro's leading role in developing magnesium technology, the company decided in 2002 to close its production plant at Porsgrunn and instead concentrate on further developments of its facility in Becancour, Canada, built in the early 1990s. It also established access to metal in China.
http://www.newton.dep.anl.gov/askasci/chem03/chem 0 3547.htm
www.cabrillo.edu/~rroland//CHEM1A/JoshLabManual/1 1 -HeatofCombustion(Magnesium).doc
Bet it was nearly this model: http://laptopmag.com/Review/Dell-Latitude-D620.ht m
Magnesium, a silvery white metal of atomic weight 24.32, ignites at 632C and burns at 1982C, with magnesium oxide (MgO) as its combustion product. In an exothermic reaction, metallic magnesium can ignite to produce magnesium dihydroxide (ie, Mg(OH)2) and hydrogen. Magnesium is used in either powdered or solid form as an incendiary agent for both illumination and antipersonnel purposes. Various alloys of magnesium (eg, aluminum/zinc/magnesium alloy found in US M126 round) are mechanically sturdier but also can be ignited easily.
Thermite is a mixture of powdered or granular aluminum and powdered iron oxide. When combined with other substances, such as binders, the material is termed a "thermate." All such materials react vigorously when heated to the combustion temperature of aluminum. This reaction produces aluminum oxide, elemental iron, and sufficient heat to melt the iron. The reaction temperature is approximately 2200C.