This invention relates generally to battery device mechanical design. More specifically, the invention relates to prevention of thermal run-away in batteries through the use of an endothermic reaction.
The battery industry is continually expanding to meet the increasing energy needs of the portable equipment, transportation, and communication markets. Lithium-ion is becoming the industry standard battery chemistry due to its high energy density, sealed design and high availability in world markets.
Lithium-ion batteries are produced in a number of variations; the most popular lithium-ion batteries, which have the highest energy density, use a cobalt or nickel-cobalt oxide anode. These batteries have the ability to create their own internal supply of oxygen when overheated. More specifically, oxygen is liberated from the oxide material of the anode at elevated temperatures, which can occur due to a variety of causes, such as an internal short circuit, overcharging, or other cause. Since both oxygen and fuel are internally available to the cells, a fire can start within a single battery cell, and can be difficult to extinguish with conventional methods. In some cases, the fire will continue until all the flammable materials in the battery, i.e., in all of the cells, have been exhausted.