HEAT-ABSORBING POUCHES

Described herein are devices and methods for mitigating thermal runaway in electrical energy storage batteries. A pouch includes a seal and a sealed opening. Within the pouch are a porous support material (such as concrete, glass, cellulous, etc.) and a heat absorbing material (such as water, hydrogel, an organic liquid, etc.) For example, water may be a heat absorbing material and a glass framework may be used as a support material. For example, a pouch may be placed on either side of a lithium battery in a battery pack, and when the lithium battery enters thermal runaway, the heat absorbing material my change phase from a liquid to a vapor, and the vapor pressure causes the sealed opening to open, and the vapor to escape the pouch. This allows the heat to be released from the battery pack and protects the neighboring batteries from an increase in temperature.