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Title: Thermal stability studies of Li-ion cells and components

Abstract

A Li-ion cell consists of a carbon-based negative electrode (NE); a porous polymer membrane separator (high density polypropylene and/or polyethylene); and positive electrode (PE) containing lithium transition metal oxides (LiMo{sub 2}, M = Co, Ni, or Mn); and a mixture of lithium salt and organic solvents provides an electrolytic medium for Li-ions to shuttle between the PE and NE. Electrodes are produced by coating slurries of active PE or NE material, polymer binder, most commonly polyvinylidene difluoride (PVDF), and small amounts of high surface area carbon onto a metallic current collectors. Thermal stability of fully charged 550 mAh prismatic Li-ion cells (Sn-doped LiCoO{sub 2}/graphitic carbon) and their components are investigated. Accelerating rate calorimetry (ARC) is used to determine the onset temperature of exothermic chemical reactions that force the cell into thermal runaway. Differential scanning calorimetry (DSC) and thermogravimetry analysis are used to determine the thermal stability of the cell's positive electrode (PE) and negative electrode (NE) materials from 35 to 400 C. The cell self-heating exothermic reactions start at 123 C, and thermal runaway occurs near 167 C. The total exothermic heat generation of the NE and PE materials are 697 and 407 J/g, respectively. Heat generations of the NEmore » and PE materials, washed in diethyl carbonate (DEC) and dried at {approx}65 C under vacuum, are significantly lower than unwashed samples. Lithium plating increases the heat generation of the NE material at temperatures near the lithium melting point. Comparison of the heat generation profiles from DSC and ARC tests indicates that thermal runaway of this cell is close to the decomposition temperature range of the unwashed PE material. The authors conclude that the heat generation from the decomposition of PE material and reaction of that with electrolyte initiates thermal runaway in a Li-ion cell, under thermally or abusive conditions.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Motorola Energy Systems Group, Lawrenceville, GA (US)
OSTI Identifier:
20003174
Resource Type:
Journal Article
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 146; Journal Issue: 9; Other Information: PBD: Sep 1999
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 25 ENERGY STORAGE; METAL-NONMETAL BATTERIES; CARBON; LITHIUM OXIDES; STABILITY; COBALT OXIDES; NICKEL OXIDES; MANGANESE OXIDES; BATTERY SEPARATORS

Citation Formats

Maleki, H., Deng, G., Anani, A., and Howard, J. Thermal stability studies of Li-ion cells and components. United States: N. p., 1999. Web. doi:10.1149/1.1392458.
Maleki, H., Deng, G., Anani, A., & Howard, J. Thermal stability studies of Li-ion cells and components. United States. doi:10.1149/1.1392458.
Maleki, H., Deng, G., Anani, A., and Howard, J. Wed . "Thermal stability studies of Li-ion cells and components". United States. doi:10.1149/1.1392458.
@article{osti_20003174,
title = {Thermal stability studies of Li-ion cells and components},
author = {Maleki, H. and Deng, G. and Anani, A. and Howard, J.},
abstractNote = {A Li-ion cell consists of a carbon-based negative electrode (NE); a porous polymer membrane separator (high density polypropylene and/or polyethylene); and positive electrode (PE) containing lithium transition metal oxides (LiMo{sub 2}, M = Co, Ni, or Mn); and a mixture of lithium salt and organic solvents provides an electrolytic medium for Li-ions to shuttle between the PE and NE. Electrodes are produced by coating slurries of active PE or NE material, polymer binder, most commonly polyvinylidene difluoride (PVDF), and small amounts of high surface area carbon onto a metallic current collectors. Thermal stability of fully charged 550 mAh prismatic Li-ion cells (Sn-doped LiCoO{sub 2}/graphitic carbon) and their components are investigated. Accelerating rate calorimetry (ARC) is used to determine the onset temperature of exothermic chemical reactions that force the cell into thermal runaway. Differential scanning calorimetry (DSC) and thermogravimetry analysis are used to determine the thermal stability of the cell's positive electrode (PE) and negative electrode (NE) materials from 35 to 400 C. The cell self-heating exothermic reactions start at 123 C, and thermal runaway occurs near 167 C. The total exothermic heat generation of the NE and PE materials are 697 and 407 J/g, respectively. Heat generations of the NE and PE materials, washed in diethyl carbonate (DEC) and dried at {approx}65 C under vacuum, are significantly lower than unwashed samples. Lithium plating increases the heat generation of the NE material at temperatures near the lithium melting point. Comparison of the heat generation profiles from DSC and ARC tests indicates that thermal runaway of this cell is close to the decomposition temperature range of the unwashed PE material. The authors conclude that the heat generation from the decomposition of PE material and reaction of that with electrolyte initiates thermal runaway in a Li-ion cell, under thermally or abusive conditions.},
doi = {10.1149/1.1392458},
journal = {Journal of the Electrochemical Society},
number = 9,
volume = 146,
place = {United States},
year = {1999},
month = {9}
}