While the commercial market is moving toward
rechargeable power sources, military users are consuming the
primary power sources (non rechargeable batteries) due to the
simple logistics, long shelf life, readiness and robustness.
Performance requirements for
grade portable power sources are much more demanding than
commercial batteries. Military equipment requires high power
and light weight (more power per volume unit). Weight
consideration is a critical aspect, especially for dismounted operations.
Military specs are also more demanding in the operating
temperature and humidity range, water and salt resistance, as well
as safety. These requirements limited the variations of primary
battery chemistries and designs. In recent years, several armies
have shifted to the use of rechargeable batteries for peacetime,
training and garrison operations, as well as
uses, to save in cost and transportation.
consideration for primary batteries is clear - combat readiness
require immediate response, therefore, immediate availability of
full and consistent power, no charging and priming before use -
dictates the use of primary batteries that have
no voltage delays, even after long storage periods. The
implementation of modern lithium batteries significantly increased
power density and reduced weight, when compared to earlier
alkaline and carbon-zinc technology. One such technology is the
matured Lithium sulfur dioxide (Li/SO2) primary battery
technology. However, one of the major concerns for military users
was the pressurized cylinders that compose the Li/SO2 cell. These
cylinders contain electrolytes stored at high pressure that can
explode if punctured by enemy fire or physical abuse. New
production processes of Li/SO2 batteries have utilized
non-pressurized cells. For example, a lithium-manganese dioxide
(Li/MnO2) cell is constructed as a laminated, aluminized pouch
that offers high energy density. Another concern was the emission
of hazardous gases, in case of short circuit or overheating.
Modern designs, especially those used in night vision equipment,
are now being replaced with Li/MnO2 cells that have safety
features to automatically shut down of the battery, when
overheated. Modern portable electronic equipment is now moving
toward the new Li/MnO2 chemistry, which has higher energy density
than Li/SO2, since the cell utilizes the entire battery cavity.