Battery parameters

Electromagnetic Telemetry. The electromagnetic telemetry is usually powered downhole with batteries. Parameters such as gamma ray, resistivity and temperature, can be transmitted while tripping up or down. Since a two-way communication is possible, the system can be switched to a logging only mode to transmit only the logging information. 

In DC-based systems, the battery bank acts like a power damper, smoothing any short-term or long-term fluctuations, resulting from the renewable power units or the demand side. Regulation is mainly based on a few battery parameters such... 

Monitoring systems measure and display key battery parameters. The main objective is to detect cell or battery module failures at an early stage. The replacement of a cell or module can then be accomplished with a short system downtime as and when necessary. Monitoring systems normally measure cell/module voltages, current and temperature, and estimate cell/module state-of-charge (SoQ and/or state-of-health (SoH). Such systems have been used in UPS applieations for many years. 

Internal battery parameters can only be measured by the use of speeial sensors [5], which leads to high costs. Most of the known methods are based on eleetrolyte measurements. According to the cell reaction of the lead-acid battery, the eleetrolyte is not only necessary for the ionic transport but is also necessary for the charge and discharge reactions. The ions of the electrolyte take part in the reactions. This results in a linear relation between the SoC and the ionic concentration of the electrolyte. Other electrolyte parameters vary approximately linearly with concentration. The relationship between acid rel. dens, and these other parameters is given in Table 8.2. 

In general, SoC describes the short-term changes of battery parameters whereas SoH describes the long-term changes. SoH determination does not need to be carried out continuously. Periodic measurements (e.g., once a week) are adequate for most applications. The period of measurement depends on the application. Extrapolation of SoH measurements allows a prediction of battery life. Sudden battery failures, however, also occur, e.g., cracking of a faulty weld. Failures such as these are very difficult to predict. To determine the SoH, it is necessary to know the actual SoC or to measure the SoH, always at the same SoC (i.e., full SoC). 

In order to extract thermal battery parameters from a measured impedance spectrum, a thermal model of the battery is necessary. This model reproduces the effects of heat capacity, thermal conductivity, heat exchange with environment, and internal losses generation. Transient simulation is then used to calculate an impedance spectrum for the battery model which is subsequently employed for parameter identification. 

Physico-chemical modelling of Li-ion batteries Parameter analysis in the frequency domain... 

Table 21.1 Battery Parameters Modeled in this Study...

Selection of the lithium-ion battery parameters for use in the fiiel-cell/battery hybrid system must start from the analysis of the predicted usage profile. The analysis includes estimates of the expected power and energy requirements for the battery within the hybrid system and selecting the most effective cell formulation and/ or chemistry for the task. The optimization of the hthium-ion cell characteristics... 

Simplex optimization was used for conductivity optimization but, of course, will be useful for the optimization of all battery parameters, e.g., aging of the battery due to unstable composition of the additives and electrolyte. The method can also be used for improving the power or energy density of the cell, if it is applied to the electrode composition. Because the simplex method is not only suitable for optimizing problems of one single outcome variable, this method can be used for the optimization of the total battery. By defining the desired parameters and their importance for the performance... 

The peak power during discharge, defined as the power at 2/3 OCV, is independent of SOC so that the vehicle performance and dynamic is constant over the whole SOC range [6]. Obviously this is important for practical reasons. Typical battery parameters are summarized in Figure 10.8. 

Battery Parameters. The key battery parameters of the flat battery are similar to those of the cylindrical one. The flat configuration provides low resistance by virtue of the geometry. The thin layers need to stay in intimate contact to maintain the low resistance and gassing... 

Table 3. Battery Parameters for Lithium-Manganese Spinel/Lithium-Titanate Batteries for HEVs and PHEVs.

Battery Parameters HEV 10-Mile PHEV 20-Mile PHEV... 

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