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The heat generation rate of a lithium ion cell was estimated using a reversible heat generation rate equation. Because the equation is based on the energy conservation law, the influence of kinetically slow processes should be considered. In this analysis, the influence of kinetically slow processes is present but it is small within the domain of the test measurements. This approximation can be of significant usefulness for modeling the thermal response of single cells and multi-cell batteries.

Deep charge and discharge cycling of 24 Volt battery strings composed of two 12 Volt VRLA batteries wired in series affects reliability and life expectancy. This is a matter of interest in vehicle power source applications. These cycles include those specific operational cases requiring the delivery of the full storage capacity during discharge. The concern here is related to applications where batteries serve as a primary power source and the energy content is an issue. It is a common practice for deep cycling a 24 volt battery string to simply add the specified limit voltages during charge and discharge for the individual 12 Volt batteries. In reality, the 12 Volt batteries have an inherent capacity variability and are not identical in their performance characteristics. The actual voltages of the individual 12 Volt batteries are not identical.

The US Army has been pursuing the development of a Smart Battery as part of its on-going efforts for reducing operation and maintenance costs of the Army's ground vehicles. This effort has revealed that the smart battery has a much broader significance beyond that of an operations and maintenance cost reduction exercise. The smart battery is creating a new way of defining what a battery is. The use of smart batteries has a direct bearing on vehicle readiness and enabling system-wide power management.

Evidence has been adduced supporting the existence of induced interfacial stirring associated with the passage of current in flooded lead acid batteries. This interpretation is supported by measurements made under three distinct experimental conditions. First, the effect appears consistent with the modeling of the current response observed during constant voltage charging. Second, Electrochemical Impedance Spectroscopy (EIS) measurements show the effect of transitions between stirring and quiescent environments. Finally, studies using applied voltage pulses at microelectrodes further support this induced mass transfer condition.

The US Army has recently transitioned to using “maintenance free” batteries in its ground vehicles to increase the over-all vehicle readiness. Using lead-calcium alloy grids in place of the “reduced maintenance” design decreases water loss. This loss of water is known to be a measure of the battery self discharge. In this study, the charging of SLI batteries was examined over a range of operating temperatures as a means for characterizing the self-discharge rate as a function of battery voltage and temperature. The battery response was modeled analytically. Current activities are directed toward achieving a better description of the battery self-discharge over extreme environmental conditions.