FY2010 - Oak Ridge National Laboratory

Director’s R&D Fund—
Energy Storage
performed to simulate the pinch test on a solid aluminum brick. Second, deformation during the pinch test
on a prismatic lithium-ion battery cell was simulated using the validated procedure.
Mechanical and thermophysical properties. The cells were opened and the thermal diffusivity of the
“jelly-rolls” was tested in the through-thickness and in-plane directions. Mechanical properties of the cell
materials were also tested. Components such as the separator, copper, and aluminum current collectors
were taken from the jelly-roll, and the stress-strain curves of the materials were generated. Other
characterizations carried out include optical microscopy and scanning electron microscopy for imaging
and analyzing the damaged layers.
Test rig design and setup. The test setup consists of a servo-hydraulic mechanical testing machine
equipped with digital controllers for load and displacement and full feedback control; an environmental
chamber with IR-transparent windows to contain gases and by-products from lithium-ion battery thermal
runaway events; sets of spheres of different diameter and materials; and attachment rods to transfer
compressive loads into prismatic batteries.
Internal short circuit testing. A series of ISC tests were performed to create internal shorts with controlled
size and volume: 800 mAh prismatic cell phone cells were subjected to the pinch test using balls with
diameter ranging from 0.25 to 3 in. in diameter. In order to achieve control of the initial short size, the
loading speed, the short detection threshold, and stop mode were studied. Five 1.5 Ahr lithium-polymer
cells were tested. The pinch tests were clearly able to distinguish regular cells and cells with special
separators.
Mesoscale simulation of internal short circuit. A phase field simulation tool was developed for a model
electrode-electrolyte system that couples the evolution of the potential field and the concentration fields.
The model is capable of tracking the spatial variation of the electrode potential and the concentration
within the electrode as a function of discharge time. The simulations are also able to capture the overall
discharge kinetics as a function of the current. The mesoscale simulations will be used to predict the
electrochemical heat source that contributes to thermal runaway.
Information Shared
Maleki, Hossein, Hsin Wang, Edgar Lara-Curzio, and Wei Zhang. 2010. “Internal Short Circuit Test
Design for Li-Ion Cells.” 2010 IMLB Conference, Montreal, June 27–July 2.
05506
Achieving Rechargeable Lithium-Air Batteries through Metal Oxide
Electrocatalysts
Ye Xu, William A. Shelton, Gabriel M. Veith, Nancy J. Dudney, Jane Y. Howe, and Jason P. Hodges
Project Description
Lithium–oxygen has one of the largest theoretical energy densities of any practical electrochemical
couple at nearly 12 kWh/kg. Prototype lithium-oxygen cells based on carbon cathodes suffer substantial
overpotentials in both discharging and charging and rapid capacity loss with cycling. Several recent
studies have reported improved overpotentials and capacity by including organometallic compounds,
metals, and metal oxides to carbon cathodes. The improvements nonetheless remain quite insufficient,
and these studies are very limited in the mechanistic understanding that they provide of the cathode ORR
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