Safety Performance of 5 Ah Lithium Ion Battery Cells Containing the Flame Retardant Electrolyte Additive (Phenoxy) Pentafluorocyclotriphosphazene

Abstract

Investigations on the effect of flame retardant additives (FRs) on the abuse tolerance of large scale lithium ion battery (LIB) cells (5 Ah) are of high relevance in battery science and industry but rarely performed as they are cost and time consuming. In addition, even though FRs are frequently investigated, their positive effect on the safety properties of larger full LIB cells under abusive condition has not been proven yet. The promising FR (phenoxy) pentafluorocyclotriphosphazene (FPPN) is known to exhibit excellent flame retardant-and electrochemical properties at the same time.Therefore, FPPN is investigated towards abuse tolerance in 5 Ah LIB cells in this study. Calorimetric investigations show that a mass percentage of 5 wt % FPPN mixed to a standard electrolyte, significantly reduces the self-heating rate of 5 Ah cells in the temperature range from 80°C to 110°C. While nail penetration and external short circuit experiments provide no significant difference between standard and FPPN-containing cells, an increased overcharge tolerance and a favorable thermal stability at � 120°C in overcharge and oven experiments could be shown. [a] T. . Nail penetration experiment of 5 Ah cells containing electrolyte with (blue) and without (black) 5 wt % FPPN. a) scheme showing the position of the thermocouples. b) Voltage over time of two cells per additive mixture. Temperature over time of two cells per electrolyte mixture are presented in c) for thermocouple position 1 and in d) for thermocouple position 2. . Overcharge experiment of 5 Ah cells containing electrolyte with (blue) and without (black) 5 wt % FPPN. a) Voltage and b) temperature (position 1) vs. time diagrams of two cells per additive mixture are presented.

Thermal Effect and Mechanism Analysis of Flame-Retardant Modified Polymer Electrolyte for Lithium-Ion Battery

“…However, high-energy-density lithium-ion batteries generate substantial heat when releasing energy, which leads to a high risk of thermal runaway. In recent years, accidents involving the spontaneous combustion of electric vehicles have occurred frequently [ 1 , 2 , 3 ]. On 7 January 2021, a workshop operated by a subsidiary company of Contemporary Amperex Technology Co. exploded due to the thermal runaway of battery waste, resulting in a giant mushroom cloud.…”

High‐Throughput Experimentation and Computational Freeway Lanes for Accelerated Battery Electrolyte and Interface Development Research

“…Discovery and development of novel functional materials with targeted properties traditionally involves a large number of trial tests following a series of procedures, see, e.g., on flame retardants for liquid electrolytes. [14][15][16][17] However, these efforts are inevitably far from time-efficient considering the near infinite chemical space. Current materials design approaches are still mostly based on human knowledge and intuition, as well as on low throughput experiments.…”

Abuse‐Tolerant Electrolytes for Lithium‐Ion Batteries

“…Besides, phenoxy (pentafluoro) cyclotriphosphazene (FPPN, Figure 14a) showed better FR performance and excellent electrochemical properties as well. Dagger et al [73] studied the thermal abuse resistant properties of a 5 Ah battery with a standard electrolyte containing fire retardant additives. The electrolyte containing 5 wt% phosphazene composited FR (I: PFPN, II: FPPN) could completely suppress the flammability for around 11s (Figure 14b).…”

“…c,d,f) Reproduced with permission [72]. Copyright 2018, Elsevier B.V. e) Reproduced with permission [73]. Copyright 2018, Wiley-VCH.…”