Internal resistance variances in lithium-ion batteries and implications in manufacturing
Name
815725069-MIT.pdf
Description
Full printable version
Size
17.12 MB
Format
Adobe PDF
Checksum (MD5)
7c49378f982a7e5b2a9ef590c0ca13ee
Author(s)
Gogoana, Radu
Advisor(s)
Sanjay E. Sarma.
Date Issued
2012
Publisher
Massachusetts Institute of Technology
Abstract
This thesis addresses issues in manufacturing that lead to cell DC internal resistance (DCIR) variance, provides an overview of generally accepted cell degradation mechanisms and modeling techniques associated with IR as a function of cycling, models the cycle life of a simple battery pack of two parallel-connected cells that start off as unbalanced, and validates it with experimental data from cycle life testing of parallel-connected LiFePO₄ cell groups. Experimental results from samples of commercially available cells show that variance in the thickness of the electrode layer is correlated to differences in capacity and DCIR. In cycle-life testing, parallel-connected cell groups with larger differences in DCIR between the cells experienced faster cycle life degradation. The proper matching of DCIR values within a battery pack, relative to the designed C-rate capability of the pack, is important to ensuring maximum useful life of the battery pack. This is especially important for parallel-connected cell groups, where the current distribution to each cell is typically not monitored in order to reduce battery management system complexity.
Description
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2012.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 80).
Subjects
Mechanical Engineering.
MIT Department
Massachusetts Institute of Technology. Department of Mechanical Engineering
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