Stress-Based State of Health and Charge Measurement for Intercalation Batteries

Princeton Docket # 12-2792

The determination of a battery’s state of charge (SOC) and state of health (SOH) are important for the power management system that relies on batteries as a power source, e.g., mobile phones, laptops, electric vehicles, grid level storage, etc. Despite its fundamental importance in battery systems, SOC and SOH measurements are not straightforward and remain an area of active research.

Researchers in the Department of Mechanical and Aerospace Engineering at Princeton University have proposed a novel method of determining SOC and SOH from simple measurements of mechanical stress, which varies predictably with SOC and SOH. Stress-based measurements are particularly attractive because stress is a cell parameter that is relatively sensitive to SOC/SOH, in contrast to other commonly measured cell parameters such as voltage and current. Stress-based measurements can be used to compliment or even replace battery management systems based on more complicated dynamic system models and charge counting algorithms, resulting in higher battery pack performance and longevity.

Applications:

· Measure the state of health (SOH) and state of charge (SOC) of a battery

· Applicable to lithium-ion cells in electric vehicles, portable electronics, medical devices, and grid-scale applications.

Advantages:

· Straightforward stress-SOH/SOC relations do not require complex computations

· SOH/SOC measurements do not require complete discharge

· Able to account for SOC discharge due to self-discharge

Publications

Arnold, C.B.; Cannarella, J. “Mechanical measurement of state of health and state of charge for intercalation batteries.” US Patent 20140107949 A1. 17 April 2014.

J. Cannarella, C. B. Arnold, “State of health and charge measurements in lithium-ion batteries using mechanical stress,” J. Power Sources, 269 (2014) 7-14.

Inventors

Craig Arnold is Associate Professor in the Department of Mechanical and Aerospace Engineering and Associate Director of Academic Affairs in the Princeton Institute for Science and Technology of Materials. His research primarily focuses on laser processing and transport in materials with particular emphasis on shaping laser-material interactions. Among many awards and honors Professor Arnold has won are the NSF Career Award (2006) and ONR Young Investigators Award (2005).

John Cannarella is a 5^th year Ph.D. candidate in the Department of Mechanical and Aerospace Engineering. His research investigates coupled mechanical and electrochemical phenomena occurring in lithium-ion batteries, with a focus on degradation and failure. John was the recipient of the prestigious Wallace Memorial Fellowship from Princeton University in 2014 and the Department of Defense’s NDSEG fellowship in 2010. Prior to attending Princeton, John received a B.S. in Mechanical Engineering from Rensselaer Polytechnic Institute.

Intellectual Property Status

US Patent 20140107949 A1 published 17 April 2014.

Princeton is seeking to identify appropriate partners for the further development and commercialization of this technology.

Contact

Michael Tyerech
Princeton University Office of Technology Licensing • (609) 258-6762• tyerech@princeton.edu

Laurie Bagley
Princeton University Office of Technology Licensing • (609) 258-5579• lbagley@princeton.edu