Christopher Hendricks1,3, Bhanu Sood2, and Michael Pecht3
1 Naval Surface Warfare Center, West Bethesda, MD 20817
2 Quality and Reliability Division, Safety and Mission Assurance Directorate, NASA Goddard Space Flight Center, Greenbelt, MD 20771
3 Center for Advanced Life Cycle Engineering, University of Maryland, College Park, MD, 20742, USA
For more information about this article and related research, please contact Prof. Michael G. Pecht
Lithium-ion battery diagnostics and prognostics rely on measurements of electrical impedance, capacity, and voltage to infer the internal state of the battery. Mechanical changes to the cell structure represent an additional measure of the battery’s state because these changes are related to the overall battery health. As lithium-ion batteries are charged and discharged, lithium ions are inserted or removed from the anode and cathode, a process called intercalation and deintercalation. As lithium ions intercalate and de-intercalate, they can cause changes to the lattice of the electrode particles, resulting in volumetric changes. These volumetric changes cause mechanical stresses and strains on the lithium-ion battery electrodes, and subsequently, the whole cell’s thickness varies as it is charged and discharged. This paper presents a study on the use of surface-mounted strain gauges for in-situ measurement of structural changes to lithium-ion batteries, along with a characterization of the unit-to-unit differences in strain response. A neural network modeling structure is then used to predict the battery’s depth of discharge under dynamic discharge conditions.
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