An electrochemical kinetic model (EKM) is developed, describing the electrochemical hydrogen stor... more An electrochemical kinetic model (EKM) is developed, describing the electrochemical hydrogen storage in hydride-forming materials under equilibrium conditions. This model is based on first principles of electrochemical reaction kinetics and statistical thermodynamics and describes the complex, multi-stage, electrochemical (de)hydrogenation process. A complete set of equations have been derived, describing the equilibrium hydrogen partial pressure and equilibrium electrode potential as a function of hydrogen content in both solid-solution and two-phase coexistence regions. The EKM has been applied to simulate the isotherms of thin film Pd electrodes of various thicknesses. Good agreement between experiment and theory is found in all cases. Relevant energy and kinetic parameters are obtained from the simulations.
Recent computational simulations of ionic conductivity across the electrolyte of commercial batte... more Recent computational simulations of ionic conductivity across the electrolyte of commercial batteries by Salvadori et al. (2015) have shown that the concentration of ions exceeds half the saturation limit near the electrodes. This observation, which is in agreement with other approaches by Danilov and Notten (2008) , implies that the widespread assumption of infinite dilution far from saturation is questionable. The present contribution is therefore devoted to investigate the role of saturation in modeling ionic transport in the electrolyte of Li-ion batteries. An important result is found, that saturation has no effect on the diffusivity, whereby the condition of electroneutrality is well approximated in the solution. However saturation affects the electric potential up to 40% near the electrodes for all charge rates.
An advanced model is proposed, describing the capacity losses of C 6 /LiFePO 4 batteries under st... more An advanced model is proposed, describing the capacity losses of C 6 /LiFePO 4 batteries under storage and cycling conditions. These capacity losses are attributed to the growth of a Solid Electrolyte Interface (SEI) at the surface of graphite particles in the negative electrode. The model assumes the existence of an inner and outer SEI layer. The rate determining step is considered to be electron tunneling through the inner SEI layer. The inner SEI layer grows much slower than the outer SEI layer. Another contribution to the degradation process is the exfoliation of SEI near the edges of graphite particles during discharging and the formation of new SEI induced by the volumetric changes during the subsequent charging. The model has been validated by storage and cycling experiments. The simulation results show that the capacity losses are dependent on the State-of-Charge (SoC), the storage time, cycle number and graphite particle size. The model can be used to predict both the calen...
ABSTRACT A novel approach in modeling the ionic transport in the electrolyte of Li-ion batteries ... more ABSTRACT A novel approach in modeling the ionic transport in the electrolyte of Li-ion batteries is here presented. Diffusion and migration processes govern the transport of ions in solution in the absence of convection. In the porous electrode theory [1] it is common to model these processes via mass balance equations and electroneutrality. A parabolic set of equations arises, in terms of a non constant electric field which is afflicted by the paradox of being generated without electrical charges. To remedy this contradiction, Maxwell's equations have been used here, coupled to Faraday's law of electrochemical charge transfer. The set of continuity equations for mass and Maxwell's equations lead to a consistent model, with distinctive energy characteristics. Numerical examples show the robustness of the approach, which is well suited for multi-scale analyses [2,3].
ABSTRACT The use of biofuel cells (BFC) is a promising approach to generate electricity. BFC can ... more ABSTRACT The use of biofuel cells (BFC) is a promising approach to generate electricity. BFC can be successfully applied to achieve long-term autonomous operation of miniaturized implantable Body-Area-Network (BAN) devices. BAN devices are important for the development of future healthcare technologies. Glucose-based enzymatic BFC are a good option to power BAN devices due to the high availability of the fuel (glucose) in body fluids. Moreover, it shows excellent catalytic selectivity and good chemical safety. In this paper, the design of a glucose-based enzymatic BFC demonstrator is described and the performance of both the individual electrodes and the complete cell is evaluated. The measured maximum power output of the designed BFC-demonstrator was 5.8 μWcm-2. Additionally, the kinetics of the detailed energy conversion processes, occurring inside the BFC system, have been investigated from both an experimental and theoretical point of view. The proposed model describes the glucose oxidation at the anode of a BFC and includes the diffusion for all (electro-) chemically active species. The modeling results are qualitatively and quantitatively in good agreement with the experimental results.
2011 IEEE Vehicle Power and Propulsion Conference, 2011
ABSTRACT Successful introduction of Plug-in Electrical Vehicles (PEV) increases the requirements ... more ABSTRACT Successful introduction of Plug-in Electrical Vehicles (PEV) increases the requirements for advanced on-board Battery Management Systems (BMS) significantly. Modern BMS provides the driver for a number of important indications, such as remaining operation time, adaptive State-of-Charge and State-of-Health. The core of an advanced BMS is a mathematical model for the battery (pack). However, the high complexity and the large amount of computing power necessary for a proper implementation of such models creates a barrier for their introduction to automotive applications. In the present paper a simple dynamic model, describing the behavior of the battery voltage is therefore proposed. The approach is experimentally validated for 18650-type of Li-ion cells.
An electrochemical kinetic model (EKM) is developed, describing the electrochemical hydrogen stor... more An electrochemical kinetic model (EKM) is developed, describing the electrochemical hydrogen storage in hydride-forming materials under equilibrium conditions. This model is based on first principles of electrochemical reaction kinetics and statistical thermodynamics and describes the complex, multi-stage, electrochemical (de)hydrogenation process. A complete set of equations have been derived, describing the equilibrium hydrogen partial pressure and equilibrium electrode potential as a function of hydrogen content in both solid-solution and two-phase coexistence regions. The EKM has been applied to simulate the isotherms of thin film Pd electrodes of various thicknesses. Good agreement between experiment and theory is found in all cases. Relevant energy and kinetic parameters are obtained from the simulations.
Recent computational simulations of ionic conductivity across the electrolyte of commercial batte... more Recent computational simulations of ionic conductivity across the electrolyte of commercial batteries by Salvadori et al. (2015) have shown that the concentration of ions exceeds half the saturation limit near the electrodes. This observation, which is in agreement with other approaches by Danilov and Notten (2008) , implies that the widespread assumption of infinite dilution far from saturation is questionable. The present contribution is therefore devoted to investigate the role of saturation in modeling ionic transport in the electrolyte of Li-ion batteries. An important result is found, that saturation has no effect on the diffusivity, whereby the condition of electroneutrality is well approximated in the solution. However saturation affects the electric potential up to 40% near the electrodes for all charge rates.
An advanced model is proposed, describing the capacity losses of C 6 /LiFePO 4 batteries under st... more An advanced model is proposed, describing the capacity losses of C 6 /LiFePO 4 batteries under storage and cycling conditions. These capacity losses are attributed to the growth of a Solid Electrolyte Interface (SEI) at the surface of graphite particles in the negative electrode. The model assumes the existence of an inner and outer SEI layer. The rate determining step is considered to be electron tunneling through the inner SEI layer. The inner SEI layer grows much slower than the outer SEI layer. Another contribution to the degradation process is the exfoliation of SEI near the edges of graphite particles during discharging and the formation of new SEI induced by the volumetric changes during the subsequent charging. The model has been validated by storage and cycling experiments. The simulation results show that the capacity losses are dependent on the State-of-Charge (SoC), the storage time, cycle number and graphite particle size. The model can be used to predict both the calen...
ABSTRACT A novel approach in modeling the ionic transport in the electrolyte of Li-ion batteries ... more ABSTRACT A novel approach in modeling the ionic transport in the electrolyte of Li-ion batteries is here presented. Diffusion and migration processes govern the transport of ions in solution in the absence of convection. In the porous electrode theory [1] it is common to model these processes via mass balance equations and electroneutrality. A parabolic set of equations arises, in terms of a non constant electric field which is afflicted by the paradox of being generated without electrical charges. To remedy this contradiction, Maxwell's equations have been used here, coupled to Faraday's law of electrochemical charge transfer. The set of continuity equations for mass and Maxwell's equations lead to a consistent model, with distinctive energy characteristics. Numerical examples show the robustness of the approach, which is well suited for multi-scale analyses [2,3].
ABSTRACT The use of biofuel cells (BFC) is a promising approach to generate electricity. BFC can ... more ABSTRACT The use of biofuel cells (BFC) is a promising approach to generate electricity. BFC can be successfully applied to achieve long-term autonomous operation of miniaturized implantable Body-Area-Network (BAN) devices. BAN devices are important for the development of future healthcare technologies. Glucose-based enzymatic BFC are a good option to power BAN devices due to the high availability of the fuel (glucose) in body fluids. Moreover, it shows excellent catalytic selectivity and good chemical safety. In this paper, the design of a glucose-based enzymatic BFC demonstrator is described and the performance of both the individual electrodes and the complete cell is evaluated. The measured maximum power output of the designed BFC-demonstrator was 5.8 μWcm-2. Additionally, the kinetics of the detailed energy conversion processes, occurring inside the BFC system, have been investigated from both an experimental and theoretical point of view. The proposed model describes the glucose oxidation at the anode of a BFC and includes the diffusion for all (electro-) chemically active species. The modeling results are qualitatively and quantitatively in good agreement with the experimental results.
2011 IEEE Vehicle Power and Propulsion Conference, 2011
ABSTRACT Successful introduction of Plug-in Electrical Vehicles (PEV) increases the requirements ... more ABSTRACT Successful introduction of Plug-in Electrical Vehicles (PEV) increases the requirements for advanced on-board Battery Management Systems (BMS) significantly. Modern BMS provides the driver for a number of important indications, such as remaining operation time, adaptive State-of-Charge and State-of-Health. The core of an advanced BMS is a mathematical model for the battery (pack). However, the high complexity and the large amount of computing power necessary for a proper implementation of such models creates a barrier for their introduction to automotive applications. In the present paper a simple dynamic model, describing the behavior of the battery voltage is therefore proposed. The approach is experimentally validated for 18650-type of Li-ion cells.
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Papers by D. Danilov