Kirill Murashko

Three-Dimensional Thermal Model of a Lithium Ion Battery for Hybrid Mobile Working Machines: Determination of the Model Parameters in a Pouch Cell

Effective heat transfer and protection against high operating temperatures are important, lifetime-affecting items in the design and operation of batteries, especially those intended for hybrid mobile working machines, where the peak power and current demands are high. This paper describes a methodology for the modeling of the electrical and thermal behavior of lithium ion pouch cells for hybrid mobile working machines. The model is produced by coupling the equivalent electrical circuit of the pouch cell and the 3-D pouch cell thermal model. The temperature dependence of the battery operation parameters is added to the model in order to analyze the influence of temperature on heat generation during battery operation. Determination of the parameters of the thermal model is carried out empirically based on the presented methodology, which allows the construction of a 3-D thermal model of a pouch cell without requiring detailed information about the battery chemistry. The validity of the modeling procedure is demonstrated experimentally for a 60 Ah lithium titanate pouch cell.

Thermal Analysis of the Laminated Busbar System of a Multilevel Converter

Laminated busbar systems are commonly used in power electronic converters because of their low stray inductance. While the electromagnetic analysis of a busbar system is widely presented in the literature, there is a lack of accurate thermal modeling. In this paper, the thermal analysis of the busbar system is presented. An analytical lumped parameter thermal model (LPTM) of the busbar system is developed. The LPTM is applied to the fast estimation of the mean temperature and temperature-dependent power losses of the busbars by the proposed algorithm. Joule losses produced by nonsinusoidal currents flowing through the busbars in the converter are estimated. The skin and proximity effects, which have a strong influence on the ac resistance of the busbars, are considered in the loss estimation. Thus, a comprehensive electrothermal model of the busbar system is developed, which is of practical use in the converter design. It allows optimizing the stray inductance, material consumption, and cost of the busbar system as long as the specified temperature limits are not exceeded. The finite-element method thermal modeling validates the developed LPTM. Laboratory measurements in two operating points of the converter have been performed, and they show good correlation with the simulation results.

Towards a better energy efficiency through a systems approach in an industrial forklift system

The purpose of this study is to improve the potential energy recovery to electric energy in an electrohydraulic forklift system. The initial result achieved for the energy saving ratio after structural optimization is 40%. Component optimization is applied to the tested drive; this consists of an electric servomotor with direct torque control which is directly running a reversible hydraulic pump. According to the study, the energy efficiency and the energy recovery from the electrohydraulic forklift system can be increased by 11%. New ideas and directions for further research were obtained during the study.

Carbon nanotube supercellulose supercapacitor

Supercellulose gel and single-wall carbon nanotubes (SWCNTs) were used for the creation of binder-free electrode for supercapacitor application and the properties of the electrode were investigated in aqueous electrolyte. Two layers of the formed composite material were inserted on graphite current collectors and separated from each other by a separator to create a supercapacitor prototype for measurements. Different concentrations of SWCNTs were studied and 65% concentration of SWCNTs resulted in the highest specific capacitance.

Natural cellulose ionogels for soft artificial muscles

Rapid development of soft micromanipulation techniques for human friendly electronics has raised the demand for the devices to be able to carry out mechanical work on a micro- and macroscale. The natural cellulose-based ionogels (CEL-iGEL) hold a great potential for soft artificial muscle application, due to its flexibility, low driving voltage and biocompatibility. The CEL-iGEL composites undergo reversible bending already at ±500mV step-voltage values. A fast response to the voltage applied and high ionic conductivity of membranous actuator is achieved by a complete dissolution of cellulose in 1-ethyl-3-methylimidazolium acetate [EMIm][OAc]. The CEL-iGEL supported cellulose actuator films were cast out of cellulose-[EMIm][OAc] solution via phase inversion in H2O. The facile preparation method ensured uniform morphology along the layers and stand for the high ionic-liquid loading in a porous cellulose scaffold. During the electromechanical characterization, the CEL-iGEL actuators showed exponential dependence to the voltage applied with the max strain difference values reaching up to 0.6% at 2 V. Electrochemical analysis confirmed the good stability of CEL-iGEL actuators and determined the safe working voltage value to be below 2.5V. To predict and estimate the deformation for various step input voltages, a mathematical model was proposed.

Modelling of the battery pack thermal management system for Hybrid Electric Vehicles

The Lithium-ion batteries are widely used as energy sources in different hybrid systems, however, the operation characteristics of the battery in such systems are strongly dependent on the operation temperature and therefore, with purpose to improve these characteristics a good thermal control system should be utilized. This paper describes the modelling thermal management system for the battery pack in Hybrid Electric Vehicles (HEVs), which gives opportunity to control the operation temperature of the pack for different load cycles and ambient temperatures. The thermal model of the battery pack is created by using an equivalent electrical circuit with lumped parameters. The thermal control system is created as a combination of the cooling system of the internal combustion engine and the battery pack thermal control system. The heat transfer between these systems is performed by a plate heat exchanger where the inlet flow is controlled by a three-way valve with an electric actuator. Artificial intelligent algorithms together with estimator are applied in control system, with purpose to obtain suitable control properties.

Optimization of the passive thermal control system of a lithium-ion battery with heat pipes embedded in an aluminum plate

In the design and operation of batteries, effective heat transfer and protection against high operation temperatures are significant issues affecting the lifetime of the battery. This is particularly the case for batteries intended for hybrid machines, where the peak power and current requirements are high. This paper introduces a structure of the thermal protection system for the high-power lithium-ion batteries to be applied to hybrid machines and a methodology for their optimization. The proposed structure is based on the use of metal plates and heat pipes, providing an opportunity to decrease the nonuniform temperature distribution in pouch-type cells. The efficiency of the proposed thermal control system is verified by modeling in Comsol Multiphysics, which is connected to MATLAB for the optimization of the placement and number of heat pipes. Multidimensional unconstrained nonlinear minimization is applied during the optimization in MATLAB.