B BATTERIES Contents Nomenclature Capacity Energy Self-Discharge Charging Methods Fast Charging Charge–Discharge Curves Partial-State-of-Charge Adaptive State-of-Charge Determination Dynamics Alternating Currents Parallel and Series Connections Modeling Lifetime Prediction Codes and Standards Nomenclature P Kurzweil, University of Applied Sciences, Amberg, Germany & 2009 Elsevier B.V. All rights reserved. Sign Conventions and Potential Definitions Every electrochemical cell – primary cell, secondary cell, fuel cell, electrochemical capacitor, electrolysis cell, or corrosion element – consists basically of two electrodes, also called the two half-cells, dipping into an electrolyte. At the electrodes, electrochemical reactions take place that involve electrons as reactants. Definitions of Conductors, Reactants, and Cell Polarity Electrode: An electronic conductor e.g. of metal, carbon, graphite, metal oxide (such as PbO 2 ,MnO 2 ), or semi- conducting materials. The polarity of the electrode refers to the charges residing at its surface and its terminal to which the external electric circuit is connected. Electrolyte: An ionic conductor, liquid, solid, or fused, which transports the electric current by the mobility of ions, for example, water-based or organic salt solutions, diluted acids or bases, salt melts, oxide ion conducting ceramics (such as ZrO 2 ), or conducting polymers. Posi- tive charge carriers are referred to as cations; negative charge carriers as anions. The intrinsic conductivity of pure water is too low to be an appropriate electrolyte: k ¼ 0.0635 mScm À1 at 25 1C owing to autoprolysis (2H 2 O"H 3 O þ þ OH À ). At the electrode–electrolyte interface change occurs from conduction by electrons to conduction by ions. Anode: The electrode at which electrochemical oxidation takes place, a chemical reaction that results in the release of electrons by the active material, so that the oxidation 381 . or fused, which transports the electric current by the mobility of ions, for example, water-based or organic salt solutions, diluted acids or bases, salt melts, oxide ion conducting ceramics. B BATTERIES Contents Nomenclature Capacity Energy Self-Discharge Charging Methods Fast Charging Charge–Discharge. Reactants, and Cell Polarity Electrode: An electronic conductor e.g. of metal, carbon, graphite, metal oxide (such as PbO 2 ,MnO 2 ), or semi- conducting materials. The polarity of the electrode refers to