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    Multi-scale short circuit resistance estimation method for series connected battery strings
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    In order to integrate a ferroelectric-based device into a larger circuit, one must create an equivalent circuit model for the device. Ferroelectric materials contain a number of complicated parameters that make this task far from trivial. In a Ba0.5Sr0.5TiO3-based capacitor, for example, the capacitance and leakage current vary with applied voltage, temperature and frequency. In addition, at high frequencies the equivalent series inductance and resistance (ESL and ESR) become non-negligible. All of these factors must be understood and quantified in order to create a working circuit. Such an analysis is reported for capacitors fabricated from Pt/BST/Pt films.
    Equivalent series resistance
    Equivalent series inductance
    Film capacitor
    Ceramic capacitor
    Citations (6)
    Safety of lithium-ion battery (LIB) has become a major concern for many large-scale energy storage systems. Particularly, collision-induced internal short circuit (ISC) can trigger thermal runaway of LIB cells in electric vehicles. Our previous study on LIB coin cells suggested that with an appropriate microstructure, the current collector might favorably modify the failure mode of electrodes and drastically reduce the heat generation rate of ISC. In the current study, we scaled up the technique of microstructured current collector and applied it to LIB pouch cells. Through debossing, surface patterns were rapidly generated on large current collector sheets in a controlled manner. Impact tests demonstrated the high effectiveness of the processed current collectors for thermal runaway mitigation.
    Thermal Runaway
    Current collector
    Citations (1)
    An alternative thermal runaway initiation method for Li-ion cells has been developed based on the principles of inductive heating. Thermal runaway has been successfully triggered for different battery types, such as 3.1 Ah 18650 cylindrical cells, 39 Ah pouch and 94 Ah hard casing prismatic cells. A short burst of heat (few seconds) corresponding to only 1% of the electric energy of the cell is injected into the cell. The alternating electric field induces eddy current which heats up locally the conductive parts of the cell. Then through heat transfer the separator melts which results in internal short circuit. The initial short circuit develops to a hard internal short which triggers thermal runaway 10–20 s after the heater is switched off. The propagation of the initial internal short to thermal runaway can be observed visually by sparks and as open circuit voltage fluctuations. This newly discovered internal propagation may provide further insights into the failure mechanism of a single cell upon internal short and hence allow the development of new concepts to mitigate thermal propagation.
    Thermal Runaway
    Separator (oil production)
    Internal heating
    Formulae relating equivalent series resistance and capacitance of the traditional capacitor equivalent circuit, to frequency and the physical parameters of a capacitor are demonstrated. Spiral-wound cylindrical capacitors without schooping end-spray connections were used to model metallized film disconnected from direct connection to the schooping in corroded capacitors. The simple formulae for equivalent series resistance and capacitance, derived empirically from the diffusion equation modeling, were found to accurately reproduce experimental results for model experimental capacitors. Source or connection impedance was found to accurately model a rise in dissipation factor at higher frequencies. Application of the formulae to a new power capacitor effectively modeled the performance of the capacitor including the self-resonance peak. Best fit values for external inductance and source resistance were used in this modeling. Inclusion in the discrete model of a series resistance inversely proportional to frequency effectively modeled the flat low-frequency dissipation factor of the commercial polypropylene capacitor
    Equivalent series resistance
    Equivalent series inductance
    Filter capacitor
    Equivalent impedance transforms
    Tantalum capacitor
    Film capacitor
    In commercial solar cells, the pattern of the front electrode is critical to effectively assemble the photo generated current. The power loss in solar cells caused by the front electrode was categorized as four types. First, losses due to the metallic resistance of the electrode. Second, losses due to the contact resistance of the electrode and emitter. Third, losses due to the emitter resistance when current flows through the emitter. Fourth, losses due to the shading effect of the front metal electrode, which has a high reflectance. In this paper, optimizing the number of finger on a 4 × 4 solar cell is demonstrated with known theory. We compared the short circuit current density and fill factor to evaluate the power loss from the front metal contact calculation result. By experiment, the short circuit current density(Jsc), taken in each pattern as 37.61, 37.53, and 37.38 mA/cm2 decreased as the number of fingers increased. The fill factor(FF), measured in each pattern as 0.7745, 0.7782 and 0.7843 increased as number of fingers increased. The results suggested that the efficiency(Eff) was measured in each pattern as 17.51, 17.81, and 17.84 %. Throughout this study, the short-circuit current densities(Jsc) and fill factor(FF) varied according to the number of fingers in the front metal pattern. The effects on the efficiency of the two factors were also investigated.
    Equivalent series resistance
    Contact resistance
    Open-circuit voltage
    Power density
    A new technique is developed for the precise determination of the equivalent circuit parmeters of a quartz crystal resonator: the series resonance frequency, the series resistance, the series inductance, and the capacitance ratio. This technique is unique in that the parameters are determined from the measured data of the crystal admittance by means of computer processing.
    Admittance
    Equivalent series resistance
    Crystal (programming language)
    Equivalent series inductance
    RLC circuit
    Crystal oscillator
    Citations (5)
    The analysis of the solar cell characteristics, including series resistance using a mixed-level simulation technique, is presented. Device analysis is carried out by the transmission line equivalent circuit approach and the effect of series resistance to the device is obtained using circuit-level simulation.
    Equivalent series resistance
    Network Analysis
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