Battery Safety 2012 – December 6 – 7, LasVegas, NV
- Advancements in System Design, Integration & Testing for Safety & Reliability
"Characterizing Crash Safety of Cylindrical and Pouch Li-ion Batteries using Computational Modeling"- By Elham Sahraei, PhD and Tomasz Wierzbicki, PhD, Massachusetts Institute of Technology
Mechanical integrity of Lithium-ion batteries is one of the most important issues on safety of electric cars, but the least studied topic.
As these batteries are not limited to stationary applications anymore, and are being used in vehicle battery packs, this aspect of their safety is more urgent to be characterized and quantified.
The automotive industry has realized that no battery pack could be rigid enough to ensure zero deformation to battery pack in severe enough crash conditions.
In this research, two common form factors of cylindrical and pouch batteries are characterized for several scenarios of deformation applied to these cells.
A comprehensive testing program was used to characterize the material properties of the cells under combined tension and predominantly compression and shear loading.
Then, computational models of the cells were developed.
The models successfully predict load-deformation trajectory and kinematics of the cell under various types of tests.
Additionally, the models are capable of predicting failure in the jelly-roll of the cell, indicating an internal short-circuit under mechanical deformation.
To compare the pouch and cylindrical cells tested in this research, the cylindrical cell tolerated a load of 5,500N and a deformation of about 7 mm before reaching short circuit,
while the pouch cell tolerated a load of 7,500N and a deformation of 3 mm before failure.
Predicting onset of electric short circuit is a necessary condition for possible thermal runaway.
>> More
- Advancements in System Design, Integration & Testing for Safety & Reliability
"Characterizing Crash Safety of Cylindrical and Pouch Li-ion Batteries using Computational Modeling"- By Elham Sahraei, PhD and Tomasz Wierzbicki, PhD, Massachusetts Institute of Technology
Mechanical integrity of Lithium-ion batteries is one of the most important issues on safety of electric cars, but the least studied topic.
As these batteries are not limited to stationary applications anymore, and are being used in vehicle battery packs, this aspect of their safety is more urgent to be characterized and quantified.
The automotive industry has realized that no battery pack could be rigid enough to ensure zero deformation to battery pack in severe enough crash conditions.
In this research, two common form factors of cylindrical and pouch batteries are characterized for several scenarios of deformation applied to these cells.
A comprehensive testing program was used to characterize the material properties of the cells under combined tension and predominantly compression and shear loading.
Then, computational models of the cells were developed.
The models successfully predict load-deformation trajectory and kinematics of the cell under various types of tests.
Additionally, the models are capable of predicting failure in the jelly-roll of the cell, indicating an internal short-circuit under mechanical deformation.
To compare the pouch and cylindrical cells tested in this research, the cylindrical cell tolerated a load of 5,500N and a deformation of about 7 mm before reaching short circuit,
while the pouch cell tolerated a load of 7,500N and a deformation of 3 mm before failure.
Predicting onset of electric short circuit is a necessary condition for possible thermal runaway.
>> More
