Fast charging of an electric vehicle lithium-ion battery at the limit of the lithium deposition process

Abstract

When charging a lithium-ion cell, the deposition of metallic lithium on the negative electrode surface, known as lithium plating, must be avoided. In this paper, the charging process of a commercial high energy lithium-ion pouch cell is investigated. Three-electrode test cells are assembled using electrode materials from the high energy lithium-ion pouch cell together with lithium metal as reference electrode to acquire the potential at the negative electrode-electrolyte interface. During charging, the cells’ current is controlled in a way that the negative electrode potential is maintained constantly slightly above 0 V vs. Li/Li+.The resulting current map depending on temperature and state of charge is used to control the charging process of the pouch cell. Following this new charging procedure, a state of charge of 80% is reached in 15 min at 25°C ambient temperature. Different cycle life tests are performed to examine iteratively an approach to how the charging current has to be reduced over the lifetime in order to avoid accelerated aging. To prove the practicability, the method is tested at the battery pack level.