Appendix C Definitions of Terms cont'd

DOE-SPEC-3019-96

Gel Cell

The gel cell uses a silica added to the electrolyte to form a gel which

liquifies above some fixed stress level, and converts back into a gel

when left standing. Only the electrolyte between and around the

plates will gel. The electrolyte in the pores of the plates and

microporous separators remains liquid.

Grid Alloy

Material composition of the positive plate, such as lead calcium,

lead antimony, or lead selenium.

Grid Growth

Increase in dimension of lead-battery plates caused by oxidation of

metallic lead grids into lead dioxide, which consumes more volume.

Harmonics

A sinusoidal component of a periodic wave or quantity having a

frequency that is an integral multiple of the fundamental frequency.

For example, a third harmonic is equivalent to three times the

fundamental frequency.

Insulated Tool

A tool or device which has conductive parts and is either coated or

covered with a dielectric material.

Limiting Oxygen Index

The flammability index of the plastic material used in the

(LOI)

construction of the battery jar. LOI ratings of 28 or greater are

desirable due to the plastic's ability to withstand fires rather than

contribute to them.

Pilot Cell

A selected cell whose condition is assumed to indicate the condition

of the entire battery string. The pilot cell is usually selected for

representative measurements for a select period of time. Once this

time period has elapsed, another cell from the battery string is

selected in turn to be the pilot cell.

Positive Plate

The grid and active material from which current flows to the

Construction

external circuit when the battery is discharging. The positive plate

can be composed of pure lead or a lead alloy such as calcium,

antimony, or selenium.

Sealed Valve-Regulated

Cell in which the internal environment is controlled and isolated

Type Battery

from the external atmosphere, often by using some form of vent

valve. Sealed cells often charge at above-ambient conditions to

promote recombination. The electrolyte of a sealed valve-regulated

type cell resembles petroleum jelly, versus a liquid solution as found

in flooded-cell batteries.

C-2