Adaptive On-line State-of-available-power Prediction of Lithium-ion Batteries

Fleischer, Christian,Waag, Wladislaw,Bai, Ziou,Sauer, Dirk Uwe The Korean Institute of Power Electronics 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.

Adaptive On-line State-of-available-power Prediction of Lithium-ion Batteries

Christian Fleischer,Wladislaw Waag,Ziou Bai,Dirk Uwe Sauer 전력전자학회 2013 JOURNAL OF POWER ELECTRONICS Vol.13 No.4

This paper presents a new overall system for state-of-available-power (SoAP) prediction for a lithium-ion battery pack. The essential part of this method is based on an adaptive network architecture which utilizes both fuzzy model (FIS) and artificial neural network (ANN) into the framework of adaptive neuro-fuzzy inference system (ANFIS). While battery aging proceeds, the system is capable of delivering accurate power prediction not only for room temperature, but also at lower temperatures at which power prediction is most challenging. Due to design property of ANN, the network parameters are adapted on-line to the current battery states (state-of-charge (SoC), state-of-health (SoH), temperature). SoC is required as an input parameter to SoAP module and high accuracy is crucial for a reliable on-line adaptation. Therefore, a reasonable way to determine the battery state variables is proposed applying a combination of several partly different algorithms. Among other SoC boundary estimation methods, robust extended Kalman filter (REKF) for recalibration of amp hour counters was implemented. ANFIS then achieves the SoAP estimation by means of time forward voltage prognosis (TFVP) before a power pulse occurs. The trade-off between computational cost of batch-learning and accuracy during on-line adaptation was optimized resulting in a real-time system with TFVP absolute error less than 1%. The verification was performed on a software-in-the-loop test bench setup using a 53 Ah lithium-ion cell.

Powder Metallurgy for Light Weight and Ultra-Light Weight Materials

Kieback, B.,Stephani, G.,Weiβgarber, T.,Schubert, T.,Waag, U.,Bohm, A.,Anderson, O.,Gohler, H.,Reinfried, M. The Korean Powder Metallurgy Institute 2003 한국분말재료학회지 (KPMI) Vol.10 No.6

As in other areas of materials technology, the tendency towards light weight constructions becomes more and more important also for powder metallurgy. The development is mainly driven by the automotive industry looking for mass reduction of vehicles as a major factor for fuel economy. Powder metallurgy has to offer a number of interesting areas including the development of sintered materials of light metals. PM aluminium alloys with improved properties are on the way to replace ferrous pars. For high temperature applications in the engine, titanium aluminide based materials offer a great potential, e.g. for exhaust valves. The PM route using elemental powders and reactions sintering is considered to be a cost effective way for net shape parts production. Furthermore it is expected that lower costs for titanium raw materials coming from metallurgical activities will offer new chances for sintered parts with titanium alloys. The field of cellular metals expands with the hollow sphere technique, that can provide materials of many metals and alloys with a great flexibility in structure modifications. These structures are expected to be used in improving the safety (crash absoption) and noise reduction in cars in the near future and offer great potential for many other applications.

Powder Metallurgy for Light Weight and Ultra-Light Weight Materials

Kieback B.,Stephami G.,Weibgarber T.,Schubert T.,Waag U.,Bohm A.,Andersen O.,Gohler H.,Reinfried M. 한국분말야금학회 2003 한국분말야금학회 학술대회논문집 Vol.2003 No.1

Studies of N-Doped p-ZnO Layers Grown on c-Sapphire by Radical Source Molecular Beam Epitaxy

S. V. Ivanov,A. El-Shaer,M. Al-Suleiman,A. Bakin,A. Waag,O. G. Lyublinskaya,N. M. Shmidt,S. B. Listoshin,R. N. Kyutt,V. V. Ratnikov,A. Ya. Terentyev,B. Ya. Ber,T. A. Komissarova,L. I. Ryabova,D. R. Kh 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

We report on the fabrication of p-type ZnO:N layers using radical-source molecular beam epitaxy and post-growth annealing of the samples. Plasma-activated oxygen and nitrogen fluxes are supplied via a single plasma cell. The combination of low growth temperature (350 − 400 ℃), slightly O-rich conditions, and post-growth annealing in the range of 650 − 800 ℃ results in efficient nitrogen pdoping with Hall hole concentration 3 × 1017 cm−3. The details of the structural and the electrical characterizations of the films are discussed. We report on the fabrication of p-type ZnO:N layers using radical-source molecular beam epitaxy and post-growth annealing of the samples. Plasma-activated oxygen and nitrogen fluxes are supplied via a single plasma cell. The combination of low growth temperature (350 − 400 ℃), slightly O-rich conditions, and post-growth annealing in the range of 650 − 800 ℃ results in efficient nitrogen pdoping with Hall hole concentration 3 × 1017 cm−3. The details of the structural and the electrical characterizations of the films are discussed.

Structural and Spectroscopic Properties of a 2 Inch ZnO-on-Sapphire Epiwafer Grown by Using Molecular Beam Epitaxy

I. C. Robin,C. Tavares,J. Rothman,G. Feuillet,A. H. El-Shaer,A. Bakin,A. Waag,Le Si Dang 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

The structural and the spectroscopic properties of a 2-inch ZnO epilayer grown by using molecular beam epitaxy are investigated. A 500-nm-thick substrate was grown on c-sappire by using a MgO buffer. In spite of the high dislocation density in the epilayer, temperature-dependent photoluminescence measurements show only a small decrease in the luminescence intensity between 4 K and 300 K. Time-resolved photoluminescence measurements reveal a decay time independent of temperature. Cathodoluminescence presents an inhomogeneous emission on a micrometric scale: a stronger emission is measured in small nanometric areas. A tentative explanation of this behavior is proposed.

Electrical Properties of ZnO-Based Nanostructur

Eva Schlenker,Andrey Bakin,Hergo-Heinrich Wehmann,Augustine Che Mofor,Arne Behrends,Andreas Waag 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

Single ZnO nanowires grown by vapor phase transport were contacted by Ti/Au electrodes patterned by using e-beam lithography. The current-voltage characteristics display a rectifying behavior, likely due to an interfacial insulating layer between the metal and the semiconductor. The contact resistance was determined to 85 M , the deduced carrier concentration yields 1015 cm-3 which is low and hints towards Fermi-level pinning at surface states. Spectrally-resolved photoconduction measurements reveal an increase in current only for illumination with light at an energy above the band gap energy. Scanning electron micrographs of the metal-nanowire interface show a smearing of the electrodes; however, energy dispersive X-ray element maps could not expose the elemental composition of the blurry regions. Single ZnO nanowires grown by vapor phase transport were contacted by Ti/Au electrodes patterned by using e-beam lithography. The current-voltage characteristics display a rectifying behavior, likely due to an interfacial insulating layer between the metal and the semiconductor. The contact resistance was determined to 85 M , the deduced carrier concentration yields 1015 cm-3 which is low and hints towards Fermi-level pinning at surface states. Spectrally-resolved photoconduction measurements reveal an increase in current only for illumination with light at an energy above the band gap energy. Scanning electron micrographs of the metal-nanowire interface show a smearing of the electrodes; however, energy dispersive X-ray element maps could not expose the elemental composition of the blurry regions.

Microscopic Origin of the Near-Band-Edge Emission in Aqueous Chemically-Grown ZnO Nanorods

C. Bekeny,T. Voss,B. Hilker,J. Gutowski,R. Hauschild,H. Kalt,B. Postels,A. Bakin,A. Waag 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.5

The microscopic origin of the near-band-edge emission in low-temperature aqueous chemicallygrown ZnO nanorods is analyzed. For the as-grown nanorods, a broad and almost featureless main emission band at 3.366 eV is observed due the presence of a high donor and defect density. After the nanorods have been annealed at 800 ℃ for 1 hour in an oxygen atmosphere, a remarkable reduction of the linewidth of the near-band-edge emission from 10 meV to 4 meV is observed. Sharp and distinguishable excitonic transitions are visible. Time-resolved photoluminescence measurements show very fast recombination times of 11 ps for the as-grown sample while the radiative recombination time increases to 80 ps after the sample is annealed in oxygen atmosphere.

Dye-Sensitized Solar Cells on the Basis of ZnO Nanorods

Bianca Postels,Anna Kasprzak,Tobias Buergel,Andrey Bakin,Eva Schlenker,Hergo-Heinrich Wehmann,Andreas Waag 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

We report on the fabrication of solid-state dye-sensitized solar cells with ZnO nanorods as n-type material and CuSCN as p-type material. The ZnO nanorods were grown on ITO-coated glass by using a low-temperature aqueous chemical growth approach employing dierent growth times. If the growth time is changed, the nanorod morphology can be varied in lentgh and diameter. CuSCN was deposited on the dye-coated ZnO nanorods from a solution in di-n-propyl sulphide, so that the nanorods are fully embedded in CuSCN. The ZnO/dye/CuSCN solar cells show photocurrents of 0.26 mA/㎠, an open circuit voltage of 0.34 V and an energy conversion efficiency of 0.1 %. We report on the fabrication of solid-state dye-sensitized solar cells with ZnO nanorods as n-type material and CuSCN as p-type material. The ZnO nanorods were grown on ITO-coated glass by using a low-temperature aqueous chemical growth approach employing dierent growth times. If the growth time is changed, the nanorod morphology can be varied in lentgh and diameter. CuSCN was deposited on the dye-coated ZnO nanorods from a solution in di-n-propyl sulphide, so that the nanorods are fully embedded in CuSCN. The ZnO/dye/CuSCN solar cells show photocurrents of 0.26 mA/㎠, an open circuit voltage of 0.34 V and an energy conversion efficiency of 0.1 %.