Abstract
The impact of elevated temperature charge-discharge cycling on thermal conductivity (K-value) of Lithium Ion Polymer (LIP) cells of various chemistries from three different manufacturers was investigated. These included high voltage (Graphite/LiCoO2:3.0-4.35 V), wide voltage (Si:C/LiCoO 2:2.7-4.35 V) and conventional (Graphite/LiCoO2:3.0-4.2 V) chemistries. Investigation results show limited variability within the in-plane and through-plane K-values for the fresh cells with graphite-based anodes from all three suppliers. After 500 cycles at 45 °C, in-plane and through-plane K-values of the high voltage cells reduced less vs. those for the wide voltage cells. Such results suggest that high temperature cycling could have a greater impact on thermal properties of Si:C cells than on the LIP cells with graphite (Gr) anode cells we tested. This difference is due to the excess swelling of Si:C-anode based cells vs. Gr-anode cells during cycling, especially at elevated temperatures. Thermal modeling is used to evaluate the impact of K-value changes, due to cycles at 45 °C, on the cells internal heat propagation under internal short circuit condition that leads to localized meltdown of the separator.
Original language | English |
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Pages (from-to) | 223-230 |
Number of pages | 8 |
Journal | Journal of Power Sources |
Volume | 263 |
DOIs | |
State | Published - Oct 1 2014 |
Funding
Authors would like thank Inna Kerzhner-Haller (Motorola Mobility Products Safety) for testing the cells cycle-life at 45 °C. This work was supported in part by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy.
Funders | Funder number |
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U.S. Department of Energy | |
Office of Energy Efficiency and Renewable Energy | |
Vehicle Technologies Office |
Keywords
- High voltage Li-Ion polymer cells
- Si:C Li-Ion polymer cells
- Thermal conductivity
- Thermal modeling
- Thermal properties