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Several state of charge estimation algorithms have been developed and validated in the past. However, due to varying validation methods, the results cannot be compared. This paper presents an approach for a generalised validation and benchmark method for state of charge estimation algorithms. The independence of standardised driving cycles is obtained by developing a synthetic load cycle. To do so, a frequency analysis is performed for 149 different driving cycles and the five major time constants are identified at 55.8 s, 9 s, 5.1 s, 3.8 s and 1 s. Using the synthetic load profile, three validation profiles are created. In addition to low- and high-dynamic behaviour, long-term stability is considered at five different temperatures (−10 °C, 0 °C, 10 °C, 25 °C and 40 °C). During the long-term test, the temperature varies between −10 °C and 40 °C. To ensure comparability, a quantitative rating technique is introduced for estimation accuracy, transient behaviour, drift, failure stability, temperature stability and residual charge estimation to evaluate the performance of different state estimation algorithms. Furthermore, the benchmark can be used to optimise the state estimator, such as a linear and an extended Kalman filter examined within this study.

Local inhomogeneous electrode utilization in recent lithium-ion batteries tends to increase due to larger sizes and/or higher densification, which poses a challenge for accurate, model-based monitoring. Pseudo-two dimensional (p2D) physicochemical models (PCM) can offer such locality via calculating local potentials and concentrations through the thickness of the electrode stack and are numerically reduced for implementation in a microcontroller in this work. Finite difference method combined with solid-diffusion approximations and orthogonal collocation reformulation are applied to generate three MATLAB- and three microcontroller-suitable C -code p2D-PCMs, which are experimentally validated towards constant current charge/discharge and driving cycle loads on a high-energy NMC-811/SiC-18650 lithium-ion battery. Benchmarking to an equivalent circuit model reveals similar mean cell voltage errors below 20 mV for the driving cycle. Reducing spatial elements reveals errors below 1% for local ( i.e. concentrations/potentials) and global states ( i.e. cell voltage/temperature) and is applied to speed-up the C -code p2D-PCMs in the microcontroller (max. 168 MHz with 192 kB RAM) to calculate at least 37% faster than real-time. Real-time computability is investigated via varying processor frequencies and using hardware acceleration schemes. The memory allocation to solve and store the p2D-PCMs on the microcontroller require 115 kB and 213 kB at a maximum, respectively.

Using the metal-insulator transition that takes place as a function of carrier density at the LaAlO$_3$-SrTiO$_3$ interface, oxide diodes have been fabricated with room-temperature breakdown voltages of up to 200 V. With applied voltage, the capacitance of the diodes changes by a factor of 150. The diodes are robust and operate at temperatures up to 270 C.

Experimental results obtained from a 500 Hz, 750 W average output power XeCl laser are presented. The dynamical behavior of the pulse energy and optical investigations of the discharge volume pointed out the limits of the present design. There are strong indications that acoustic perturbations currently prevent the efficient operation of the module at repetition rates higher than 500 Hz. To pass the 1 kW level, further improvements must be made. Increasing the discharge efficiency from 1.1% to date will reduce the creation of shock waves. An aerodynamically designed flow loop will help to shift the ratio of fan power to excitation power (currently 40 kW and 66 kW, respectively) to more reasonable values. The additional use of pulse compression techniques will simplify the choice of adequate high-voltage switching elements.© (1991) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

A historical overview over the development of excimer lasers into the multi-100 Watt range is given. Special emphasis is on efforts in Japan and Europe concerning excimer lasers with an average power exceeding 1 kilowatt. The overview includes a discussion of the different excitation mechanisms.

We report the generation of 80 fs pulses at 248 nm using a hybrid dye-excimer laser system. These pulses are amplified in a wide-aperture amplifier to 900 GW peak power.

Photocurrents in polyvinylcarbarzole were studied over 10 decades in time. An analytical approach is proposed for extracting rate distributions from the measured photocurrents. We find that the trapping-rate distribution is not exponential but ``flat'' and that it shows a cutoff at low rates. This distribution gives rise to the novel feature of a gradual transition from dispersive to nondispersive charge transport during a single transit. The temperature and field dependence of the cutoff rate ${r}_{c}$ was studied in the framework of a Poole-Frenkel model.

We briefly review dispersive transport and treat in more detail the multiple-trapping mechanism. We consider the problem of transient current spectroscopy: Given the experimental current I(t) how does one extract a distribution of rates? Extensive new measurements were made in a well studied polymeric material.

The pulse duration of discharge-pumped excimer lasers in general assumes values between 10 and 40 ns. For several purposes, including pulse transmission through optical fibers, longer pulses are required. This can be accomplished by (i) optimizing the gas mixture aiming at longest possible pulse duration instead of maximum energy, (ii) by modifying the electric circuit of standard excimer lasers, or (iii) by designing special discharge circuits including the prepulse technology.

X-ray preionization is a well-known technique for initiating homogeneous glow discharges in large aperture excimer lasers /1,2/. Here we report on preionization studies in XeCl, KrF and also — to our knowledge for the first time — ArF excimer gas mixtures. These experiments were performed by means of a recently developed industrial-grade X-ray tube.

One approach to influence the current flow through the battery pack is to implement switching circuits. Two switching elements are necessary for each cell-stage to be bypassed or activated. This allows active load management. Thus the utilisation of the battery pack can be maximised in every situation. Adaptive control algorithms allow several kinds of operating strategies. Furthermore, dynamic output voltage can be generated to serve the best output for the downstream voltage level. A battery pack with an additional connection at its central point allows the generation of sine-shaped output voltages. As consequence of individual load management, different types of batteries or even different kinds of energy storages can be interconnected to built serial hybrid electrical energy storages. This novel approach allows precisely tailored battery packs for each application to enhance performance and energy supply.

Knowing the temperature distribution within a battery pack is vital, because of the impact on capacity loss, power degradation and safety. Temperature measurements are usually realized with temperature sensors attached to a limited number of cells throughout the battery pack, leaving the majority of cells in larger battery systems unattended. This work presents a novel sensorless method for determining the temperature of a cell by exploiting the relation of the cell’s overpotential and temperature exemplary using a 18650 nickel-rich/silicon–graphite cell, although the method is basically applicable to any cell. Current changes in the battery load are utilized as pulse excitation for the calculation of a direct-current resistance R DC, Δ t determined after a certain time Δ t . Reference pulses at 10/20/30/40 ° C are recorded to investigate the influence of state-of-charge and pulse rise/fall-time, as well as the pulse-current amplitude and direction on R DC, Δ t . The analysis of the reference pulses shows that a Δ t in the 10 ms to 100 ms regime has the greatest sensitivity to temperature and the least dependence on other parameters. The method is finally validated using a 6s1p-module with an externally constant temperature gradient applied to the serial connection, showing an average estimation error smaller than 1 K for each cell.