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This paper presents a three dimensional model that simulates the operation of two particular configurations of a lithium iron phosphate (LiFePO4) battery – spirally wound and prismatically wound. Understanding how these batteries operate is important for the design, optimization, and control of their performance, safety and durability. While 1D approximations may be sufficient for small scale or single cell batteries, these approximations are limited when scaled up to larger batteries, where significant three dimensional gradients might develop including lithium ion concentration, temperature, current density and voltage gradients. The model presented here accounts for all of these gradients in three dimensions by coupling an electrochemical model with a thermal model. This coupling demonstrates how electrochemical performance affects temperature distribution and to a lesser extent how temperature affects electrochemical performance. Results generated include temperature influences on current distribution and vice versa, an exploration of various cooling environments’ effects on performance, design optimization of current collector thickness and current collector tab placement, an analysis of lithium plating risk, and a comparison of energy density between the two configurations.

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A novel, flexible lead-free piezoelectric nanogenerator was developed using a uniform BaTiO3 film; synthesized by in situ conversion of titanium oxide nanotubes in a low temperature hydrothermal process.

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