Problem
The best-known lithium-ion battery model whose parameters can be calibrated entirely from a battery’s manufacturer-provided specifications (ie. internal resistance, nominal capacity, voltage at full charge, etc) was proposed by Tremblay et al and is widely use. However, it has some shortcomings. For instance, it has low fidelity at high charge and discharge rates. Moreover, it only models a cell, and does not model the battery management system. This makes it unsuitable for evaluating practical storage systems.

Solution
We propose an alternative, the Power-based Integrated (PI) model, whose parameters can also be calibrated entirely from manufacturer specifications, but has much higher fidelity across a wide range of charge/discharge rates. This model is freely available in the public domain as a Matlab system block compatible with Simulink simulation software. Access the block here.

Evaluation
We suggest using our model when:

• Simulating an energy system with storage by modeling its power flows. In this case, it is desirable to have a battery model that uses power as input because power is conserved (note that the Tremblay model uses current as input). The PI model uses power as input.
• Modeling the battery management system (BMS) – the BMS protects the cells in a battery from being damaged due to improper use such as under/over-charging. Modelling the BMS in the PI model prevents the simulated battery from being used in unrealistic ways.
• Low error – based on validation performed in the experiment, we see that the PI model has a mean absolute voltage error of less than 0.1V across a wide range of C-rates.

Citation
F. Kazhamiaka, S. Keshav, C. Rosenberg, and K.-H. Pettinger,  ”Simple Spec-Based Modelling of Lithium-Ion Batteries, ” IEEE Transactions on Energy Conversion, Vol 33, No. 4, December 2018.