Exponent recently completed a testing report comparing selected lithium-ion battery chemistries. The comparative testing included three primary tests performed on the batteries. The Crush Test showed that Valence lithium iron magnesium phosphate cells did not reach temperatures sufficiently high enough to cause melting or ejecting, flaming and/or burning debris. In addition, the peak external temperature of the Valence lithium iron magnesium phosphate cells was more than 100°C below the temperature required to initiate thermal runaway. The External Heat Test showed that the peak temperature reached by the Valence lithium iron magnesium phosphate cells was several hundred degrees lower than the cells of the other chemistries tested, and no ignition of nearby combustible material was observed during venting. The Accelerating Rate Calorimetry (ARC) Test was conducted to determine the rate of temperature increase and evaluates a material's reactivity/instability under elevated temperature conditions to assess any potential hazards for such material. Valence lithium iron magnesium phosphate chemistry showed a much lower self-heating rate, more than 100 times slower, compared to either commercially available lithium cobalt oxide or mixed metal oxide cell chemistry tested.
Based on these results, it is the opinion of Exponent that it is "improbable" that Valence's lithium iron magnesium phosphate batteries will incur the thermal runaway that causes other batteries to burst into flames or explode.