Thermal runaway hazard characteristics and influencing factors of Li‐ion battery packs under high‐rate charge condition

Abstract

In a special environment such as a high-rate charge or discharge one, the positive and negative electrode materials of a lithium ion battery may undergo a chemical exothermic reaction with an electrolyte and a binder and release a large amount of heat to cause thermal runaway, resulting in harmful consequences. In this paper, high-rate charging experiments of different types of 18650 Li-ion battery packs were performed to study the behavior and influencing factors of Li-ion battery packs when thermal runaway occurred. Automatic test equipment with battery comprehensive parameters was adopted, and a Li-ion battery thermal runaway test device was designed and used to test a series of Li-ion battery packs under high-rate charging conditions. The series of tests were conducted under different conditions of different cell spacing, pick-up point positions and connection modes. Results showed that under the above three different conditions, the initial time and the initial temperature of the thermal runaway of the Li-ion battery packs, the maximum temperature of thermal runaway and the position where the first thermal runaway battery occurred showed some regular changes. K E Y W O R D SLi-ion battery packs, thermal runaway, influencing factors, high-rate charge

Li-ion Battery Failure Warning Methods for Energy-Storage Systems

“…positive electrode-electrolyte reactions [42] , separator melting [43] , and electrolyte decomposition, generate a significant amount of gas and heat, leading to battery expansion [44] and a rapid increase in the internal pressure exceeding atmospheric pressure. Changes in the internal pressure detected by the pressure sensor can serve as an early warning signal for thermal runaway [45] .…”

Experimental Study of a Passive Thermal Management System Using Expanded Graphite/Polyethylene Glycol Composite for Lithium-Ion Batteries

“…In this experiment, the batteries in the second row and column of the 4 × 4 battery matrix were selected for temperature measurement. To monitor the operating temperature of the battery, thermocouples were affixed at three different positions: the uppermost, middle, and lowermost sections [30][31][32][33]. The starting temperature of all batteries was approximately 27 • C.…”

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“…A large amount of heat is released in a short time after that. These rapidly generated heat and gas cause LIB to expand and may eventually lead to thermal runaway (TR) 12–14 . Ouyang et al 4 divided the overcharging process into four stages: (1) 100% ≤ state of charge (SOC) < 120%, the LIB performance almost did not decline; (2) 120% ≤ SOC < 140%, loss of lithium‐ion (LLI), loss of active material (LAM) of cathode and increase for internal resistance are caused by negative lithium deposition; and (3) 140% ≤ SOC < 150%, cathode and anode underwent LAM, and gas is generated after electrolyte oxidation.…”