Batteries in a Portable World 2nd Ed.A Handbook on Rechargeable Batteries for Non-Engineers
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2.2 The Nickel Cadmium (NiCd) Battery
Alkaline nickel battery technology originated in 1899, when Waldmar Jungner invented the NiCd battery. The materials were expensive compared to other battery types available at the time and its use was limited to special applications. In 1932, the active materials were deposited inside a porous nickel-plated electrode and in 1947, research began on a sealed NiCd battery, which recombined the internal gases generated during charge rather than venting them. These advances led to the modern sealed NiCd battery, which is in use today.
The NiCd prefers fast charge to slow charge and pulse charge to DC charge. All other chemistries prefer a shallow discharge and moderate load currents. The NiCd is a strong and silent worker; hard labor poses no problem. In fact, the NiCd is the only battery type that performs best under rigorous working conditions. It does not like to be pampered by sitting in chargers for days and being used only occasionally for brief periods. A periodic full discharge is so important that, if omitted, large crystals will form on the cell plates (also referred to as 'memory') and the NiCd will gradually lose its performance.
Among rechargeable batteries, NiCd remains a popular choice for applications such as two-way radios, emergency medical equipment, professional video cameras and power tools. Over 50 percent of all rechargeable batteries for portable equipment are NiCd. However, the introduction of batteries with higher energy densities and less toxic metals is causing a diversion from NiCd to newer technologies.
Advantages and Limitations of NiCd Batteries
Advantages
Fast and simple charge — even after prolonged storage.
High number of charge/discharge cycles — if properly maintained, the NiCd provides over 1000 charge/discharge cycles.
Good load performance — the NiCd allows recharging at low temperatures.
Long shelf life – in any state-of-charge.
Simple storage and transportation — most airfreight companies accept the NiCd without special conditions.
Good low temperature performance.
Forgiving if abused — the NiCd is one of the most rugged rechargeable batteries.
Economically priced — the NiCd is the lowest cost battery in terms of cost per cycle.
Available in a wide range of sizes and performance options — most NiCd cells are cylindrical.
Limitations
Relatively low energy density — compared with newer systems.
Memory effect — the NiCd must periodically be exercised to prevent memory.
Environmentally unfriendly — the NiCd contains toxic metals. Some countries are limiting the use of the NiCd battery.
Has relatively high self-discharge — needs recharging after storage.
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The original Batteries in a Portable World book was written by Isidor Buchmann and is Copyright © Cadex Electronics Inc. (www.cadex.com). All rights reserved. No part of this publication may be reproduced, transmitted, transcribed, stored in a retrieval system or translated into any language or computer language in any form or by any means without written permission of Cadex Electronics Inc., 22000 Fraserwood Way, Richmond, BC, V6W 1J6, Canada. Tel: 604-231-7777, Fax: 604-231-7755, Toll free (US & Canada) 1-800-565-5228 email: info@cadex.com The 300-page book is available from Cadex Electronics Inc. through book@cadex.com, tel. 604-231-7777 or most bookstores. For additional information on battery technology visit www.buchmann.ca. This is an original HTML version of Batteries in a Portable World reproduced by permission. |
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