In this study, an analytical model is represented for evaluation of remaining charge state of commercial automotive-grade lithium batteries. The model is elaborated for evaluation of battery remaining charge state under dynamic loads and various temperature conditions, which is typical for operation of batteries being parts of electric or hybrid electric vehicles. It is proved that use of the Peukert equation as a part of an analytical model leads to a restriction of field-of-use for those models as the Peukert equation is not applicable under small discharge rates. It has been also shown that in modern analytical models, the usually used temperature dependencies are not applicable at extremely low and extremely high temperatures of battery discharge. The reason is that they do not take into account neither the presence of a negative thermal critical point, under which the battery capacity output becomes equal to zero, nor a limitation of a capacity growth in conditions of a temperature increase. The represented analytical model solves such problems to a large extent and provides with a good prediction accuracy for battery remaining state of charge (relative error is not more than 4% Nowadays in connection with wide spread distribution of electric vehicles and hybrid electric vehicles, -the acute need has emerged in evaluation possibility of battery residual capacity. This problem matters a great deal both for the modern lithium batteries, which at the moment are mainly used ones as parts of electric vehicles, and for traditional batteries, for example nickel-cadmium or lead-acid ones, which are widely used in area of aviation, railway vehicles, monitoring systems, electric-light services, etc.
1-4For battery residual capacity evaluation, it is possible to use the most precise electrochemical models. They take into account a transport-component (of ions, electrons, neutral particles) as well as all the kinetic electrochemical processes. 5,6 Those models contain very many hardly defined battery characteristics such as electrode geometries, electrolyte concentration, diffusion coefficients, transfer coefficients, reaction rate coefficients, and other low-level phenomena.
5-11So while the existing electrochemical models would be likely more exact in their predictions and able to provide with better results, the creation, calibration and implementation of such models requires significant computational capabilities. This makes these simulations less suitable for on-road vehicular battery prediction. Additionally, despite of the extensive efforts having been spent on such models, they can quickly become inapplicable if the system in question requires a change in battery chemistry or configuration since calibration of the models is going on for a specific battery and pack configuration. As a result, the majority of these models requires either widespread calibration, exhaustive computational resources, or fails to tune the models for dynamic discharge conditions. Both factors limit their effectiveness in mobile applica...