Investigation of Geometries and Stability for Increasing the Energy Density in Electromechanical Battery Flywheels

Abstract

This work presents a study on possible geometries in flywheels through finite element modeling (FEM). Flywheels compose a fundamental part of the electromechanical batteries. This study aims to analyze the behavior of flywheels rotating at the highest possible rotational speed to produce the best mass–energy ratio for a certain rotor geometry. For this, different flywheel models were created and simulated through successive changes in their geometry to increase the rotational speed and energy. The geometry obtained with the best performance in the form of a Gaussian solid of revolution and made entirely of the carbon fiber Hexcel UHM 12,000 allows the development of a low cost and high performance flywheel in revolutions of up to ≈279.000 rpm and stored energy density of up to ≈430 Wh/kg. Then the next step was to also increase the total energy interconnecting the solids obtained to create a battery with the highest possible energy and energy–density. Adding the study of rotational stability.