The Advanced Technology Development (ATD) Program is a multilaboratory effort to assist industrial developers of high-power lithium-ion batteries overcome the barriers of cost, calendar life, abuse tolerance, and low-temperature performance so that this technology may be rendered practical for use in hybrid electric vehicles (HEVs). Included in the ATD Program is a comprehensive diagnostics effort conducted by researchers at Argonne National Laboratory (ANL), Brookhaven National Laboratory (BNL), and Lawrence Berkeley National Laboratory (LBNL). The goals of this effort are to identify and characterize processes that limit lithium-ion battery performance and calendar life, and ultimately to describe the specific mechanisms that cause performance degradation. This report is a compilation of the diagnostics effort conducted since spring 2001 to characterize Generation 2 ATD cells and cell components. The report is divided into a main body and appendices. Information on the diagnostic approach, details from individual diagnostic techniques, and details on the phenomenological model used to link the diagnostic data to the loss of 18650-cell electrochemical performance are included in the appendices. The main body of the report includes an overview of the 18650-cell test data, summarizes diagnostic data and modeling information contained in the appendices, and provides an assessment of the variousmore » mechanisms that have been postulated to explain performance degradation of the 18650 cells during accelerated aging. This report is intended to serve as a ready reference on ATD Generation 2 18650-cell performance and provide information on the tools for diagnostic examination and relevance of the acquired data. A comprehensive account of our experimental procedures and resulting data may be obtained by consulting the various references listed in the text. We hope that this report will serve as a roadmap for the diagnostic analyses of other lithium-ion technologies being evaluated for HEV applications. It is our hope that the information contained in this report will lead to the development of new lithium-ion cell chemistries and designs that will meet the 15-year cell calendar-life goal established by DOE's FreedomCar and Fuel Partnership.« less

A baseline cell chemistry was identified as a carbon anode, LiNi0.8Co0.2O2 cathode, and diethyl carbonate-ethylene carbonate LiPF6 electrolyte, and designed for high power applications. Nine 18650-size advanced technology development cells were tested under a variety of conditions. Selected diagnostic techniques such as synchrotron infrared microscopy, Raman spectroscopy, scanning electronic microscopy, atomic force microscopy, gas chromatography, etc., were used to characterize the anode, cathode, current collectors and electrolyte taken from these cells. The diagnostic results suggest that the four factors that contribute to the cell power loss are solid electrolyte interphase deterioration and nonuniformity on the anode; morphology changes, increase of impedance, and phase separation on the cathode; pitting corrosion on the cathode current collector; and decomposition of the LiPF6 salt in the electrolyte at elevated temperature. (C) 2001 The Electrochemical Society.

The Advanced Technology Development (ATD) Program seeks to aid the development of high-power lithium-ion batteries for hybrid electric vehicles. Nine 18650-size ATD baseline cells were tested under a variety of conditions. The cells consisted of a carbon anode, LiNi{sub 0.8}Co{sub 0.2}O{sub 2} cathode and DEC-EC-LiPF{sub 6} electrolyte, and they were engineered for high-power applications. Selected instrumental techniques such as synchrotron IR microscopy, Raman spectroscopy, scanning electron microscopy, atomic force microscopy, gas chromatography, etc. were used to characterize the anode, cathode, current collectors and electrolyte from these cells. The goal was to identify detrimental processes which lead to battery failure under a high-current cycling regime as well as during storage at elevated temperatures. The diagnostic results suggest that the following factors contribute to the cell power loss: (a) SEI deterioration and non-uniformity on the anode, (b) morphology changes, increase of impedance and phase separation on the cathode, (c) pitting corrosion on the cathode Al current collector, and (d) decomposition of the LiPF{sub 6} salt in the electrolyte at elevated temperature.