Author/Authors :
Ira Bloom، نويسنده , , Scott A. Jones، نويسنده , , Edward G. Polzin، نويسنده , , Vincent S. Battaglia، نويسنده , , Gary L. Henriksen، نويسنده , , Chester G. Motloch، نويسنده , , Randy B. Wright، نويسنده , , Rudolph G. Jungst، نويسنده , , Herbert L. Case، نويسنده , , Daniel H. Doughty، نويسنده ,
Abstract :
Cells were life-cycled cells using profiles with a 3, 6, or 9% change in state of charge (ΔSOC) at 40, 50, 60, and 70 °C. From the voltage response of the cells to the life-cycle profile at each temperature, we separated the overall impedance rise into two simpler terms, Ro (ohmic) and Rp (polarization), using an equivalent circuit model. The Ro data tend to follow the expected trends (40>50>60>70 °C). Although the Rp data trends show that Rp can either decrease or increase asymptotically with time, the overall temperature-dependent behavior is similar to that of Ro. We illustrate the types of processes that can occur in one lithium-ion cell chemistry. Based on the initial rates, the processes are complex. The Ro term dominates the observable cell impedance, but Rp adds a non-trivial contribution.
