Agilent Technologies AN 372-2 manual Introduction

Introduction

Increasing demand for portable DC power has risen from improvements in battery and motor design technol- ogy. More than ever before, portable DC powered products have become available in many diverse applications. Rechargeable batteries appear in all types of products from analytical electronic equipment to power tools and toys. In some instances, these diverse applications pose different requirements on the source of DC Power. Fortunately, availability of many types of battery chemistries yield unique characteristics. Table 1 contains just some of the different battery types and their advantages.

Whether testing batteries in R&D or production environments, the test requirements for each of the different battery types are basically the same. Figure 1 shows a common test config- uration. In general, the testing of a battery involves discharging it over

a period of time to determine several specifications. This application note will concentrate on the test of second-

ary batteries because they require Figure 1. Common Test Configuration additional tests involving recharging.

Nickel-cadmium batteries, in partic- ular, are discussed because they are the most universally used type of secondary battery in today’s demand- ing applications.

Table 1. Characteristics and Applications of Different Battery Types

	Nickel-	Gelled Lead	Lithium	Carbon	Alkaline	Silver	Mercuric
	Cadmium	Acid		Zinc		Oxide	Oxide
Volts/Cell	1.2	2.0	1.5 to 1	1.5	1.5	1.5	1.4
Applications	portable	standby service,	memory backup,	average use	good general	button-sized	button-sized cells
	equipment,	rechargeable	pacemakers,		purpose battery	cells for watches	for watches and
	rechargeable		electronic			and hearing aids	hearing aids
			door locks,
			emergency
			locator
			transmitters
Charge	CC	CV, float charge	N/A	N/A	N/A	N/A	N/A
Method
Cycle Life	500+ cycles	200 cycles	N/A	N/A	N/A	N/A	N/A
Life	3 mos.	1 year	5 to 10+ years	1 to 5 years	5% loss/yr.	6% loss/yr.	4% loss/yr.
(Charged)	(–2%/day)
Operating	20°C to 70°C	–20°C to 65°C	–55°C to 75°C	–5°C to 55°C	–30°C to 55°C	–20°C to 55°C	–10°C to 55°C
Temp.
Performance	high discharge	high capacity	flat discharge,	low cost,	good energy	flat discharge,	flat discharge
Comments	rate, quick		long life, wide	sloping	density,	more energy
	charge rate		temperature	discharge,	sloping	per unit
			range, good	low energy	discharge	volume than
			energy density	density		mercuric oxide

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