Another recent article has demonstrated how these thermodynamic calculations are in general agreement with a wide range of literature calorimetry data. This calculator implements methods described in a recent review 2 for cathodes of the form Li xMO 2, where x is the degree of lithiation, (1-x) is the degree of delithiation that determines the amount of reactive material, and M is a metal or mixture of metals in the layered metal oxide. This web-based calculator estimates heats of reaction associated with thermal runway of layered metal oxide cathode materials based on the underlying thermodynamics for specific metal compositions, degrees of delithiation, and coexisting organic material (e.g. 1 However, the heat of reaction associated with layered metal oxide cathodes is a more complicated multi-step process associated with a wider variety of materials. When lithiated graphite reacts with liquid ethylene carbonate (EC) from the electrolyte to form a solid coating and gases, the predicted exothermic heat of reaction from thermodynamics is -281.4 kJ/mol of lithium in the graphite.
Thermodynamics calculator for driver#
The amount of chemical heat that can be released via these thermal runaway reactions increases with state of charge (SOC) because the heat release is proportional to the quantities of reactive electrode materials, namely lithiated graphite in the anode (LiC 6) and delithiated layered metal oxide in the cathode (MO 2).ĭetailed thermal runaway models indicate that rapid heat release from the cathode in the presence of organic electrolytes is the principal driver of thermal runaway, but heat release from the lithiated anode reacting with electrolyte must also be accounted for to accurately predict the maximum temperature of the cell, which is required for reasonable predictions of cascading cell-to-cell failure in large battery systems. The largest contributions to thermal runaway heat release within cells originate from reactions of these electrode materials with the organic solvents. Backgroundįrom the early 1990s up to the time this calculator was developed in the early 2020s, most commercial Li-ion batteries have used a graphite negative electrode (anode) with a layered metal oxide positive electrode (cathode) and an organic electrolyte composed of a mixed carbonate solvent and a salt (typically LiPF 6). Here we use thermodynamic properties of materials involved to provide a heat of reaction for bounding the potential heat release and for use in thermal runaway models to predict consequences of abuse scenarios.
An estimate of the quantity of heat that can be released is required to assess the potential severity of thermal runaway in lithium-ion batteries.
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