Battery pack tests to detect unbalancing effects in series connected Li-ion cells

In this work main unbalancing effects and causes in series connected lithium ion cells are analyzed. Literature and research papers are analyzed regarding manufacturing process and environmental issues, detecting main unbalancing aspects. There is not much work in the literature focused in unbalancing effects and causes; due to insufficient knowledge a test procedure to detect unbalancing effects and causes is presented in this work. Main unbalancing causes are detected and their effect in battery pack performance has been tested. Main factors and their influence in battery pack unbalancing and performance are presented as conclusions.