There are inherent safety risks associated with inactive lithium ion batteries leading to greater restrictions and regulations on shipping and inactive storage. Maintaining all cells of a lithium ion battery at near zero voltage with an applied fixed load is one promising approach which can lessen (and potentially eliminate) the risk of a lithium ion battery entering thermal runaway when in an inactive state. However, in a conventional lithium ion cell, a near zero cell voltage can be damaging if the anode electrochemical potential increases to greater than the potential where dissolution of the copper current collector occurs (i.e. ∼3.1 V vs. Li/Li+ at room temperature). Past approaches to yield lithium ion cells that are tolerant to a near zero volt state of charge will be reviewed and their anticipated tradeoffs discussed. Additionally, the present work introduces a novel method to prevent the anode potential from increasing to greater than ∼3.1 V vs. Li/Li+ during near zero volt storage by modifying the amount of reversible lithium in a conventional cell using a pre-lithiated anode. Specifically, LiCoO2/MCMB pouch cells fabricated with a pre-lithiated anode maintained 99% of their original capacity after three, 3 day and three, 7 day storage periods at near zero volts under fixed load. A LiCoO2/MCMB pouch cell fabricated with a pre-lithiated anode also maintained its original discharge performance after three, 3 day storage periods under fixed load at 45 °C. Thus, modifying the amount of reversible lithium in a cell with anode pre-lithiation is a promising concept to achieve lithium ion cells with high tolerance to near zero volt storage without modification to typical cell construction parameters or use of unconventional materials.
