Page 326 - Handbook of Battery Materials

296 11 Separators

Table 11.2 Automotive lead–acid battery production 1997 (million kilowatt-hour, estimate).

Polyethylene Sintered Cellulosic/glass Synthetic VRLA SLI Total
pocket PVC/rubber separators pulp/GM batteries
separators separators separators

USA–Canada 56.5 1.2 0.6 – 0.7 59.0
Europe 30.0 11.0 3.4 – 0.1 45.4
Asia–Pacific 16.3 11.4 4.5 9.8 0.3 42.3
Latin America 11.7 0.9 3.9 – – 16.5
Total (million kWh) 115.4 24.5 12.4 9.8 1.1 163.2
(%) 70.7 15.0 7.6 6.0 0.7 100.0

Despite additional indisputable advantages such as spill-proofness or flexibility of
position in the car, this design – mostly for reasons of cost – has not yet made a
breakthrough in starter battery applications.
After this stroll through history, let us consider the current markets, split
according separation systems in the various geographic areas (Table 11.2).
The microporous polyethylene pocket has succeeded worldwide; more than 70%
of all starter batteries use this form of separation. Whereas in the USA and
Western Europe the transition is essentially complete, a similar development in
the Asia-Pacific area and Latin America, and in the medium term also in Russia
and China, is expected [3].

11.2.1.3 Industrial Battery Separators
11.2.1.3.1 Stationary Battery Separators As already mentioned, at the beginning
of the twentieth century the electric power supply was still very susceptible to
load changes, requiring the use of stationary lead batteries for load leveling.
As more powerful generators were developed this application diminished, but
from the increasing dependence on general supply of electricity the need for
emergency power batteries developed, for example, for emergency lights. From
the start, the telephone systems required huge battery installations in float service,
on the one hand as buffer batteries filtering interferences from the alternating
current circuits and on the other hand permitting (as least for limited periods) an
uninterrupted service during power outages. The batteries in these applications
are charged continuously with a low current to counteract self-discharge and to
allow discharging at comparably high currents when required. Due to the level of
maintenance necessary, these batteries were initially built in an open construction,
the required electrolyte reservoir being supplied with wide electrode spacing,
frequently without any separators. Later, spacers of hard rubber – initially rods and
then corrugated spacers – were used. With the invention of PVC separators and
their low-cost industrial production process, sintered PVC separators have been
used since around 1950 and some are still employed today.