TM 10-6140-200-14
separators which are inserted between all plates. A plastic
element protector is positioned on top of the separators
which prevents mechanical damage to the element and
aids in preventing electrical shorts which occur when
particles of active material bridge the space between
plates. Terminal posts are welded to each group and are
used to electrically connect one cell to another. A typical
element is shown in Figure 1-3.
Figure 1-2. Battery cell cutaway view
jar by means of a high impact bridge which consists of a
series of support ribs. These ribs provide sediment space
below the bottom of the element to accommodate
Figure 1-3. Components of a cell
particles of active material, shed by the positive plates
during normal operation of the battery.
d. Group. This is an assembly of plates of like
b. The top of each cell is fitted with a molded rubber or
polarity connected in parallel by welding to a common
plastic cover sealed to the jar at the edges. A vent or filler
strap or busbar. A cell must contain one positive and one
cap is located in the center of the cover. This permits the
negative group. The negative group always has one more
escape of hydrogen and oxygen while the cells are gassing
plate than the positive group. One or more terminal posts
and, when removed, provides an opening through which
are welded to each.
water may be added to the cell. The positive and negative
terminal posts, which are part of the element, fit through
e. Plates. The electrodes or plates are either positive
openings in the cover. Cells prior to being connected
or negative and consist of a cast lead alloy grid and active
material. The grid provides support to the active material
together are so placed that the positive terminal of one
cell is adjacent to the negative terminal of the next. This
and becomes the primary electrical conductor. The active
permits a series connection. On some batteries the cell
materials result from the addition of chemicals to lead
covers are tightened to the terminal posts by seal nuts
oxides which are converted, by electro-chemical process-
and gaskets. On others, lead bushings are molded into the
ing, to lead dioxide in the positive and sponge lead in the
covers and welded to the terminal posts. Both methods
negative. Although negative plates made by all industrial
lead-acid battery manufacturers are pasted and essentially
prevent leakage of acid from the area around the terminal
similar, the positive plates in common use may be either
post.
tubular or pasted type.
c. Element. The element of the cell consists of one
group each of positive and negative plates meshed
(1) Tubular type. The grid of the tubular plate
together. The plates are insulated from each other by
consists of a series of cast lead rods connected at the top.
1-3
