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Keynote speakers

Electrical and acoustic properties of solid-state glass electrolytes

Francisco Muñoz, Peter Hockicko

Abstract: Solid-state electrolytes have become of a notable interest in a number of applications of electrical systems for energy storage and harvesting, and all solid-state rechargeable batteries, in particular. They possess key advantages with respect to liquid electrolytes such that they are non-contaminant and do not have flammable organic compounds, thus reducing toxicity and the risk of explosions, and they may also work as an effective separator between the electrode materials. An ideal electrolyte must have a pure ionic conductivity and high chemical and thermal stability under the conditions of operation and, within the inorganic solid electrolyte materials, glasses may offer additional improvements due to their inherent nature, without grain boundaries and great variability in both chemical composition and shape. There are well-known efficient ways to improve the performance of glasses as solid electrolytes through their chemical composition, e.g. by increasing the amount of charge carriers, introducing highly polarizable anions or through the use of secondary glass former elements. However, the study of the mechanisms of conduction for each system becomes a critical issue when optimizing the properties of the researched materials.
We will present here a review on the application of electrochemical impedance spectroscopy and acoustic attenuation spectroscopy for the study of a series of glass systems showing ionic conductivity, and which combination may allow one to establish appropriate links between the atomic glass structure and the different mobile species that contribute to the conduction mechanism. We will summarize the results obtained in phosphate glasses1 , oxynitride glasses (LiPON)2 and mixed-former glasses (Li2O-Na2OB2O3-P2O5), where in all cases we found strong correlations between the acoustic relaxation phenomena and the energetics of ionic conduction as well as with the strength of the glass network. Meanwhile impedance data in bulk amorphous systems only provide an activation energy value related to the average mobility of the conducting species, the use of acoustic attenuation does also allow for the distinction of several relaxation processes that may well be associated different ionic species or structural environments of the glass network.

Effect of optimized wireless energy transfer system on human cells

Henrieta Škovierová, Barbara Tóthová, Miroslav Pavelek, Pavol Špánik, Erika Halašová, Michal Frivaldský

 Abstract: Wireless power transfer and issues relevant to wireless charging of various types of electronic devices are still important and emerging trends in electrical engineering (1). Regarding wireless power transfer, each application requires several self-specific operational properties or transfer characteristics. A possible way to influence these parameters lies in the configuration of the main circuit of compensation network of wireless energy transfer (WET) system (2). A very important parameters of the WET system is (i) the efficiency of the entire charging system as well as (ii) the effect of optimized WET systems on living organisms.
Human fibroblasts are morphologically heterogeneous population of cells with diverse appearances depending on their location in the body and their activity. Injury of tissue displays a proliferative stimulus for fibroblasts and induces them to produce wound healing proteins. Therefore, fibroblasts are well suited for wound healing studies.
In our project, we evaluated the late effect of optimized WET system, 350 kHz and 1.3 mT electromagnetic field applied continuously on human dermal fibroblasts. After 20 min of EMF exposition, cells were incubated for another 48 h at the standard cultivation conditions (37°C; 5% CO2). The cell morphology was monitored microscopically. No differences in cell morphology and proliferation rate were determined in exposed neither in control samples. Additionally, the cell viability was determined by quantitative colorimetric MTT assay. The cell proliferation was not influenced by the presence of EMF exposition in the exposed either in control samples possessing comparable percentage of cell viability. It is important to mentioned that further designed studies, including genotoxicity and different types of cells (hematopoietic cells, neuronal cells) should be important to evaluate the positive (healing) or negative (suppression of cell division) effects of EMF exposition on living cells.

Large Lithium-Ion Battery-Powered Electric Vehicles – From Idea to Reality

Helmut Weiss

Abstract: Lithium-Ion Batteries have become the standard for powerful electrical energy supply at mobile applications. Safety is a decisive issue, not only energy per mass or cost. Moving up to the multi kWh energy range we have to keep in our mind the general destruction effects that could emerge from the basic Lithium-ion battery design. Thermal run-away with heavy impulse fire is the final result that needs some initialization as external mechanical destruction, exposure to external heat, battery terminal short-circuit, or overcharging. External measures are taken and are considered being sufficient for achieving safety. Employment of a battery management system is standard. However, an internal battery failure is possible, too. Statistics may be a nice approach to explain correct safety of our high energy battery application as long as we are not directly involved as passengers in such a hot case of a burning battery. However, a defined step beyond is definitely necessary for large Lithium-ion battery usage in ranges beyond 100 kWh and this is also highly recommended for lower ratings: Failure handling design. While standard electric cars exhibit about 20 to 50 kWh of stored energy in the Lithium-ion batteries we consider definitely larger amounts for future mobile usage, e.g. 200 kWh up to 1000 kWh on a single and, therefore, rather heavy vehicle.
Creating something new is generally done in several steps. Feasibility and design studies in paper or computer environment are a first step but do not deliver the experience of a real system tested in practical operation. In a new approach, the first step can be a demonstrator created with low costs from a running system without batteries. The experience from the demonstrator shall lead to a prototype. Definitely higher expenditure in the prototype yields a system that can be used like the prospective series vehicle. Final test of such a vehicle goes to up the limits of the design and material. This provides the way towards a field test small series where cost and fabrication is considered strongly.
Unfortunately, all problems found out only at later steps require high expenditures through re-design and re-test. Safety is a decisive issue, thus consequences in limiting the effects of burning batteries must be considered as early as possible. New approaches in drive train design and battery management are necessary for large Lithium-ion powered electric vehicles. In 2017, a 200 kWh-battery containing hybrid locomotive demonstrator was completed and tested (OeBB 1063.038 as a design of 1980). The original locomotive is running on catenary employing rectifier, voltage source DC-link and 4 PWM inverters supplying induction motors at 1600 kW total peak power. 4 units of 50 kWh each of Lithium-ion batteries became part of the DC-link and can be charged when the locomotive operates with catenary. The final design shall include at least 400 kWh of energy. This internally new locomotive involves state-of-the-art inverters, auxiliary supply system and recuperative braking while keeping the main components (mechanical case and drive, motors, transformer). In design state is a 100 tons payload mining truck. Such trucks generally use Diesel engines (about 1000 horse power) and impressive full-load-capable switchgear and a powerful retarder. One can imagine the amount of hot air created when this truck moving downslope, and also the amount of Diesel burnt and carbon dioxide produced. The innovation step employs fully electric operation only. Electric energy is directly used from a special catenary for certain and limited up-slope routes. Hereby, this e.g. 500 kWh Lithium-ion battery (subdivided into some strands) is charged up to the required level. Limited up-slope movement and horizontal driving discharges the batteries. Down-slope driving charges the batteries by active braking. Efficiency of recuperation (=active braking) is about 75%.

A new era in simulation

Tibor Bachorec, Tomáš Sedlář

Abstract: The finite element method in conjunction with advanced material models, circuit simulators and control systems enhanced with power of current computers and numerical methods brings new possibilities for digital prototypes. Combining on-line operational data from working products with digital information about those products enables the digital twin and promises to take simulation into a new era. The paper introduces the ANSYS software tools designed for complex digital real-time prototypes.

MATLAB Total Academic Headcount – features & experience

Martin Foltin, Martina Mudrová

Abstract: At almost every university around the world, MATLAB system is used extensively in teaching, research, and student projects in all fields of engineering, science, economics, and finance. More than 1 000 of these universities has already upgraded to a Total Academic Headcount (TAH) license. This type of license provides a full suite of MATLAB products to all students and university staff for use in the classroom or lab, as well as for use in off-line work in the field research or at home. There are 3 universities with the TAH license in Slovakia and the Czech Republic till now. Our goal is to provide information about TAH features and our experience arising from 1 year of TAH usage.

The current trends in IoT Technologies for customer and industrial segment

Peter Gergély

Abstract: Make designing simple and accelerate time-to-market with the On Semi IoT Kit. It offers a comprehensive portfolio of sensors, connectivity and actuator devices including new shields like low-cost RFID reader and Bluetooth Low Energy.
Examples which are available in the integrated development environment can be easily adapted to multiple applications and use cases.
Learn more about the our IoT Kit to be ready for a fast turnaround from concept to production.