Disclosed herein is a multi-cell battery pack having optimal temperature distribution throughout the battery pack and optimal air flow through the battery pack. Disclosed herein is a battery pack which provides optimal temperature distribution throughout the battery pack, wherein maximum cell temperature (Tmax) and temperature differential amongst all cells in the battery pack (ΔTcell) are optimized for efficient thermal management providing safety, improved performance and extended life of the battery pack and electrochemical cells. Also disclosed herein is a battery pack which provides optimal flow through the battery pack and minimal pressure drop (ΔP) throughout the battery pack.