3D Modelling and Study of Electrochemical Characteristics and Thermal Stability of Commercial Accumulator by Simulation Methods

Lithium-ion batteries are one of the most expanding types of batteries on the market these days. They are widely used in recent years not only in portable devices but also increasingly in the automotive industry (BMW i3, Tesla S) or in aerospace (Boeing 787, Lockheed F-35) because of their very high capacity and energy density. Demands on safety of these batteries grow with their use in more and more devices. Safety is an important issue particularly in the case of Li-Ion batteries because of the large amount of energy stored inside them and also because of their great sensitivity to the conditions in which these batteries are used. One possibility to verify the battery behaviour under different conditions (current load, temperature), is the creation of a physical-mathematical model of the battery and by using the simulation to predict its behaviour. These methods can save time when we test batteries in a real device such as in a car for example. It is equally possible to set up a model of the real battery and implement parameters of a new type of electrode material which is tested only in the laboratory into the model. Then we can, thanks to the simulation, predict the behaviour of the battery with this advanced material. Compilation of the physical-mathematical model of a real battery and verification of the model by using electrochemical testing of a real battery are discussed in this article. The real battery was discharged by different currents and its discharge characteristics were measured by a potentiostat. At the same time, this cell was scanned with a thermographic camera in order to verify its heating. Discharge characteristics and battery heating were subsequently simulated by using a physical-mathematical model. Deviations between the simulation and the measurement results obtained during heating by high current flow were very small - between 1 and 5 %.