Equitable Multi Objective Optimization Applied to the Design of a Hybrid Electric Vehicle Battery

Abstract

This work considers the impact of thermal behavior in battery design. The cell performance worsens when the operating temperature falls outside of the ideal range, and evenness of cell temperatures is sought to prevent cell electrical unbalance which may lead to performance fading and premature failure. The heat transfer between the cells and the coolant depends on the cell packaging and layout. A multiobjective optimization model is posed whose Pareto efficient designs minimize cell temperature deviations while maintaining evenness of temperature distribution. The special characteristics of the battery design problem (comparable objectives, anonymity and Pigou–Dalton principle of transfers) make it suitable for the application of the equitability preference, which is a refinement of the Pareto optimality that has not been used in engineering design. The proposed approach based on equitability is applied to compute the spacing of the cylindrical cells in a battery module that yields an optimal thermal behavior.