A Alexander Ledovskikh

Modelling of rechargeable NiMH batteries

A new mathematical model has been developed for rechargeable NiMH batteries, which is based on the occurring physical–chemical processes inside. This model enables one to simultaneously simulate the battery voltage, internal gas pressures (both PO2 and PH2) and temperature during battery operation. The model takes into account the thermodynamics, kinetics and diffusion processes occurring at/in both electrodes and in the electrolyte.

Hydride-forming electrode materials seen from a kinetic perspective

A model is proposed which includes the charge transfer reaction and the formation of adsorbed hydrogen at the electrode/electrolyte interface, absorption of hydrogen into the solid-state MH electrode, recombination of adsorbed hydrogen atoms into molecular hydrogen dissolved in the electrolyte and hydrogen in the gas phase. It was found that the rate of the charge transfer reaction, as represented by the exchange current, is dependent on the partial hydrogen pressure (P H2 ) in a rather complex way: a positive linear dependence between log I 0 and log P H2 is found at relatively low partial pressures, which subsequently passes through a maximum, turning into a negative dependence at higher partial pressures. Both the slopes of the lines and the turning points are found to be strongly dependent on the rate constants of the various reactions. The theoretical model has been verified with both switchable mirror MH thin film electrodes and multicomponent MH electrode materials, nowadays widely applied in commercial NiMH batteries. The as-deduced theoretical relationship will form the basis for the modelling of complete NiMH batteries.

Equilibrium kinetics of chemisorption processes

A new approach to describe the equilibrium kinetics of chemisorption is proposed. The description of the system is based on first-principles chemical reaction kinetics and statistical thermodynamics. The rate constants are described by using a novel way of activation energy characterization. General expressions for equilibrium gas pressure isotherms and forward/backward reaction rates are obtained as a function of surface coverage. A strong influence of attraction and repulsion interaction energies between the adsorbed species on the equilibrium kinetics is found.

Modeling of electrochemical hydrogen storage in metal hydride electrodes

Nowadays, modern civilization faces the hazardous global warming, which is a result of consumption of traditional fossil fuels. To decrease CO2 emission, sharp improvements in energy generation technologies are required. Modern society urgently needs more sustainable energy. It is commonly accepted that electricity storage systems are the key element of energy efficient technologies, and hydrogen is considered as one of the most important future energy carriers. High energy density rechargeable nickel metal hydride NiMH batteries, which are based on the principles of electrochemical hydrogen storage, play an important role in modern industrial, automotive, and portable electronics sectors. These batteries are relatively cheap, ecologically friendly, and have advantages over other types of batteries especially in transportation and automotive applications. To control the operation of hybrid electrical vehicles HEVs nowadays and plug-in electrical vehicles PEVs in the future, a new effective generation of battery management systems BMSs is required. 1-5