NOVELTY - Health assessment method involves determining states of charge of electrochemical cell (115) for each of the selected electrochemical cell compositions; identifying the states of charge and thermodynamic functions including changes in Gibbs free energy set as Delta G, changes in entropy set as Delta S and/or changes in enthalpy set as Delta H corresponding to event or condition of electrochemical cell; and comparing thermodynamic functions corresponding to event or condition of electrochemical cell to reference thermodynamic functions corresponding to event or condition of reference electrochemical cell.    USE - Health assessment method for characterizing state of health of electrochemical cell in mobile electronic device. Uses include but are not limited to lithium ion batteries, zinc-carbon (Leclanche and saline) batteries, zinc-manganese oxide alkaline batteries, lithium ion polymer batteries, lithium batteries, nickel cadmium batteries, nickel-metal hydride batteries, lead acid batteries, nickel hydrogen batteries, and other types of electrochemical cells such as fuel cells, photovoltaics cells and electrochemical capacitors and supercapacitors, and double-layer capacitors.    ADVANTAGE - Allows very accurate measurement of thermodynamic parameters, including state functions such as the Gibbs free energy, enthalpy and entropy of electrode/electro-chemical cell reactions, that enable prediction of important performance attributes of electrode materials and electrochemical systems, such as energy, power density, current rate and the cycle life of electrochemical cell due to enhanced sensitivity combined with measurement conditions that reflect thermodynamically stabilized electrode conditions. Measurement of open circuit voltages for thermodynamically stabilized conditions enables determination of state functions such as Gibbs free energy, enthalpy and entropy of electrode/electrochemical cell reactions. The use of way for measuring open circuit voltages providing good accuracy and temporal resolution provides measurements enabling accurate thermodynamic analysis of the electro-chemical cell and enhances the systems ability to correctly identify open circuit voltages representative of thermo-dynamically stabilized conditions. Provides highly versatile thermodynamic measurement system that provides information for predicting wide range of performance attributes for virtually any electrochemical system having electrode pair.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) a method of charging an electrochemical cell in a mobile electronic device; and    (2) a system for charging an electrochemical cell.    DESCRIPTION OF DRAWING(S) - The drawing shows a schematic diagram of an electrochemical thermodynamic measurement system.    Measuring unit (110)    Electrochemical cell (115)    Composition controller (120)    Temperature controller (130)    Open circuit voltage analyzer (140)