tailieunhanh - Chapter 15: Batteries, an Overview and Outlook

Some terms, which will be repeated throughout this book, shall be defined more precisely: . . . . ‘‘Portable batteries’’ are understood to be all kinds of electrochemical energy-storing devices used in portable appliances regardless of whether they are rechargeable or not. Non-rechargeable batteries are called primary cells (batteries) or dry cells (batteries). Rechargeable batteries are called secondary batteries or accumulators. Also the terms ‘‘galvanic primary’’ and ‘‘galvanic secondary’’ cells are common. . | 15 Batteries an Overview and Outlook H. A. KIEHNE D. SPAHRBIER D. SPRENGEL and W. RAUDZSUS TERMS DEFINITIONS AND CHARACTERIZING MARKS Some terms which will be repeated throughout this book shall be defined more precisely Portable batteries are understood to be all kinds of electrochemical energy-storing devices used in portable appliances regardless of whether they are rechargeable or not. Non-rechargeable batteries are called primary cells batteries or dry cells batteries . Rechargeable batteries are called secondary batteries or accumulators. Also the terms galvanic primary and galvanic secondary cells are common. According to the electromotive series of the elements there are innumerable pairs which will yield electrochemical energy accumulators. For instance take a metal and a metallic oxide and immerse them in a liquid electrolyte. These are the main parts of a cell as Figure demonstrates. All batteries are chemical energy-storage devices and they are energy converters. A primary cell releases chemical energy while being discharged. Secondary cells have a reversible energy conversion characteristic Discharge Chemical energy Electric energy Charge Copyright 2003 by Expert Verlag. All Rights Reserved. Figure Scheme of an electrochemical cell. Preconditions for the adoption of a storage system are its stable long-term durability a reasonable voltage range cheap raw materials as well as controllable substances regarding production techniques and also a regard for possible environmental damage. The nominal voltage is a value that characterizes the system Un f system The off-load voltage is dependent on the system and temperature Uo f system d and is calculable. The discharge voltage is dependent on the current UD f system d ID For secondary cells the charging voltage is dependent on the current Ul f system d Il The capacity of a battery is dependent on the system the temperature and the discharge voltage C f system d ID Us Copyright 2003 by Expert .