Experimental analysis of dynamic charge acceptance test conditions for lead-acid cells

© 2016 IEEE.This paper presents the results of a series of tests to determine the Dynamic Charge Acceptance (DCA) performance of small form-factor 2 V, 6 Ah, carbon-enhanced VRLA cells designed for Hybrid Electric Vehicle (HEV) applications. A test procedure has been written for a battery test system, based on a modified DCA Short Test profile. Results have been obtained for a batch of cells, tested at various temperatures, rest periods and states of charge. These conditions have been chosen to mimic a range of real-life scenarios which could potentially be encountered during HEV operation. The resulting analysis demonstrates clear variations and trends in DCA performance which may be used to inform conditions for future testing regimes. The same test procedure is then applied to standard lead-acid cells and the results compared

An analysis of the influence of high-frequency ripple currents on dynamic charge acceptance in lead-acid batteries

This paper presents the results of an experimental analysis of the influence of high-frequency injected ripple currents on the Dynamic Charge Acceptance (DCA) performance of lead-acid batteries. A wide-bandwidth battery model, derived from real-world data is described, this being a hybrid of the standard Randles model and a high-frequency model previously presented in literature. A bespoke test procedure is introduced, based on the existing DCA Short Test profile (EN50342-6). The results demonstrate that the injection of ripple currents can significantly improve charge acceptance, whilst having no appreciable effect on the State of Charge (SoC) of the battery. This study further demonstrates the importance of knowledge of the impedance spectrum of the battery if the improvements in DCA performance are to be achieved with maximum efficiency and effectiveness

An analysis of the influence of high-frequency ripple currents on dynamic charge acceptance in lead-acid batteries

This paper presents the results of an experimental analysis of the influence of high-frequency injected ripple currents on the Dynamic Charge Acceptance (DCA) performance of lead-acid batteries. A wide-bandwidth battery model, derived from real-world data is described, this being a hybrid of the standard Randles model and a high-frequency model previously presented in literature. A bespoke test procedure is introduced, based on the existing DCA Short Test profile (EN50342-6). The results demonstrate that the injection of ripple currents can significantly improve charge acceptance, whilst having no appreciable effect on the State of Charge (SoC) of the battery. This study further demonstrates the importance of knowledge of the impedance spectrum of the battery if the improvements in DCA performance are to be achieved with maximum efficiency and effectiveness

Millimeter wave transmission spectroscopy of gated two-dimensional hole systems

We developed a differential transmission to study cyclotron resonance of GaAs/AlxGa1 xAs two-dimensional hole samples. The technique utilizes a modulated AuPd gate isolated by a Si3N4 dielectric from the sample, which is irradiated opposite the gate by millimeter waves ranging from 2 to 40GHz. This technique effectively removes the background signal and yields a hole effective mass of 0:41me with a cyclotron scattering time of 20 ps, consistent with the previous results using different techniques

Evaluation of Agents Interactions in a Context-Aware System

The evaluation of Multi-Agent Systems (MAS) is a complex problem and it does not have a single form. Much effort has been spent on suggesting and implementing new architectures of MAS. Often these new architectures are not even compared to any other existing architectures in order to evaluate their relative benefits. The present work focuses on interactions, the most important characteristic of any complex software as autonomous agents according to [25], as a problematic of evaluation. So, in this paper, we describe the assignment of evaluation values to Agents interaction in a specific MAS architecture. This evaluation is based on the weight of the messages brought by an interaction.Funded by projects CICYT TIN2008-06742-C02-02/TSI,CICYT TEC2008-06732-C02-02/TEC, SINPROB, CAM MADRINET S-0505/TIC/0255, and DPS2008-07029-C02-02.Publicad

An experimental analysis of the effect of cell degradation on dynamic charge acceptance in lead-acid cells

Dynamic Charge Acceptance (DCA) is an important consideration for battery performance, particularly when batteries are used as power buffers within larger systems. This paper presents an experimental analysis of the effects of cycle-related degradation on the DCA performance of lead-acid cells. The results show that capacity loss due to degradation does not provide a reliable indication of the cells DCA performance, in fact for the typical lifetime of the cell DCA performance remains broadly constant, independent of degradation. Only at very severe levels of degradation is DCA performance seen to appreciably reduce. The results show that the more rapid degradation of lead cells need not be such a concern in applications where DCA performance is key. The results also have implications for second-life uses of cells in similar applications

Experimental Analysis of the Influence of High-Frequency Ripple Currents on Dynamic Charge Acceptance in Lead-Acid Batteries

This paper presents the results of a series of tests to determine the influence of high-frequency injected ripple currents on the Dynamic Charge Acceptance (DCA) performance of lead-acid batteries. A wide-bandwidth battery model is described, this being a hybrid of the standard Randles model and a high-frequency model previously described in literature. A bespoke test procedure is described, based on the existing DCA Short Test profile. The results demonstrate that the injection of ripple currents can significantly improve charge acceptance

Observation of audio-frequency edge magnetoplasmons in the classical two-dimensional electron gas

The electric admittance of a two-dimensional electron gas on liquid helium measured at audio frequencies ¿ is observed to oscillate as a function of magnetic field at strong magnetic fields. The oscillations can be attributed to the propagation of very-low-frequency (¿t~10-6, t scattering time; ¿/¿c~10-8, ¿c cyclotron frequency) edge magnetoplasmons. The directly determined dispersion relation agrees with theory and quantitatively with measurements in the collisionless regime (¿t»1). The attenuation, theoretically obtained by incorporating the screening in a simple local-capacitance model, agrees well with experiments

Generic theory of colloidal transport

We discuss the motion of colloidal particles relative to a two component fluid consisting of solvent and solute. Particle motion can result from (i) net body forces on the particle due to external fields such as gravity; (ii) slip velocities on the particle surface due to surface dissipative phenomena. The perturbations of the hydrodynamic flow field exhibits characteristic differences in cases (i) and (ii) which reflect different patterns of momentum flux corresponding to the existence of net forces, force dipoles or force quadrupoles. In the absence of external fields, gradients of concentration or pressure do not generate net forces on a colloidal particle. Such gradients can nevertheless induce relative motion between particle and fluid. We present a generic description of surface dissipative phenomena based on the linear response of surface fluxes driven by conjugate surface forces. In this framework we discuss different transport scenarios including self-propulsion via surface slip that is induced by active processes on the particle surface. We clarify the nature of force balances in such situations.Comment: 22 pages, 1 figur

Nonlinear Transport in a Quantum Point Contact due to Soft Disorder Induced Coherent Mode Mixing

We show that the coherent mixing of different transverse modes, due to forward scattering of carriers by soft impurity- or boundary potentials leads to a nonlinear, asymmetric current response of quantum point contacts (QPC). The oscillating contribution to the current is sensitive both to driving voltage and to gate voltage in direct analogy to the electrostatic Aharonov-Bohm effect. Our calculations are in a good agreement with recent experimental data showing small-scale conductivity nonlinearities and asymmetry in QPC.Comment: 4 pages, 2 figures (availiable upon request), REVTEX, Applied Physics Report 93-4