Unlocking the Safety Issues Caused By Internal Short Circuits in Lithium-Ion Batteries

Abstract

Lithium-ion batteries (LIBs) have been attracting tremendous focuses and fundamental impetus for the fast development of electric vehicles, computers, cellphones and among others . Mechanical loading may catastrophically cause battery internal short-circuit (ISC) and then usually lead to irreversible and chain reaction until the dead of the cell. Possible hazards such as excessive heat, gas/smoke, fire and explosion of LIBs triggered by ISC greatly refrains further wide application of LIBs as well as developing higher energy density LIBs. However, a clear picture of the LIB’s electrochemical safety behavior triggered by mechanical loading is still uncovered. Here we systematically show that there are three modes of electrochemical behavior for LIBs after ISC, i.e. fast voltage drainage with no thermal runaway (TR), several cycles of voltage drop-recovery followed by TR, and a significant voltage-drop followed by TR, triggered by mechanical abusive loading. By highly repeatable tests, detailed characterization and computation modeling, we found that electrochemical safety behavior of LIBs is dominated by SOC, ISC area and resistance. Our results demonstrate the safe boundary and electrochemical behavior map for LIBs after ISC. We anticipate that this discovery will lead to new opportunities for LIB safety design, manufacturing, assembling, evaluation and protection.