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/LiCoO2:2.7-4.35 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 degrees 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 degrees C, on the cells internal heat propagation under internal short circuit condition that leads to localized meltdown of the separator. (C) 2014 Elsevier B.V. All rights reserved.