Cone Calorimetry as a Tool for Thermal Hazard Assessment of Li-Ion Cells 2014-01-1838

The emergence of Plug-in hybrid electric vehicles (PHEVs) and electric vehicles (EVs) as a viable means of transportation has been coincident with the development of lithium-ion (Li-ion) battery technology and electronics. These developments have enabled the storage and use of large amounts of energy that were previously only possible with internal combustion engines. However, the safety aspects of using these large energy storage battery packs are a significant challenge to address. In addition, the rapid advances in electrode and electrolyte materials for Li-Ion batteries have made comparisons and ranking of safety parameters difficult because of the substantial variations in cell designs. In this work, we outline a method for quantifying the thermal safety aspects of Li-ion battery technologies using a Cone Calorimeter.

The Cone Calorimeter is a suitable tool to measure and quantify critical information such as the heat release rate and total energy released from the combustion of organic material. Such techniques cannot be directly applied to study the energy release characteristics, during combustion, of non-organic and energetic material like Li-ion cells. Combining data from the Cone Calorimeter with compositional analysis of the Li-ion cell components, we have adapted a calorimetric procedure to better quantify the heat release rate and the total energy released from cells when they undergo a combustion event. Using these tests, thermal hazard parameters of cells with different chemistries, sizes and form-factors can be compared directly in a quantifiable and repeatable manner. Data generated from these tests can be used in the design and implementation of fire risk mitigation strategies for battery modules and packs that are used in EVs and PHEVs. This information can also be used in developing and improving computational and analytical models for analyzing thermal runaway and cascading thermal failures in modules and packs.