This paper presents an overview of heat and mass transfer issues in advanced rechargeable batteries such as nickel-metal hydride (Ni-MH) and lithium-ion (Li-ion) batteries. These batteries are important power sources for ultra-clean, fuel-efficient vehicles and modern portable electronics. Recent demands for environmentally responsible vehicles and strong portable power have prompted fundamental studies of heat and mass transport processes in battery systems in conjunction with electrochemistry and materials science. In this paper, discussions are presented on what are the critical heat and mass transfer issues present in advanced batteries and how these issues affect the battery performance, safety, life cycle, and cost. A theoretical framework describing the transport phenomena with electrochemical reactions is provided. Selected results are presented to illustrate the importance of coupled electrochemical and thermal modeling for advanced batteries. The recent progress is also reviewed in developing and validating battery models at Penn State GATE Center for Advanced Energy Storage.