In the current study, a LiNi0.8Co0.15Al0.05O2/graphite cell has been tested to evaluate its thermal behavior during charge and discharge with constant and dynamic current profiles. For each current input condition, the irreversible heat has been calculated using the cell overpotential during the test, and the reversible heat has been determined using the entropy coefficient at different depth of discharge levels. The irreversible and global (sum of irreversible and reversible heats) heats obtained have been used to reestimate the cell skin temperature. Compared with the skin temperature measured during tests, the temperatures calculated with irreversible heat show an underestimation of the temperature for the charge State and an overestimation of the temperature for the discharge state. The temperature profiles obtained with global heat show good agreement with the experimental data. Therefore, the reversible heat has been found to be a significant portion of the total heat generated and should not be neglected in lithium ion battery thermal management. (C) 2013 The Electrochemical Society. All rights reserved.