Renata SA Safety Guidelines - Manual (Page 4)

UL safety tests
Safety Guidelines
54
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Abnormal Charging Test
The cells were charged by being connected in
opposition with a 12 V dc power supply. The
current was controlled by connecting a resistor of
the appropriate size in series with the cell. The
test duration was based on the applied current
and the capacity oft he cells.
The cells were examined after these tests for any
sign of change.
Five samples each of Models 1000-0, 1000-7
and CR2450N in the as-received condition were
used in these tests.
None of the cells leaked. There were
no fires or explosions as a result of tests at
currents below 100 mA for the abnormal charging
mode.
Results
Crush Tests
The cells were crushed between a flat surface
and a cylindrical surface having a radius of
curvature of 5/16 in. The force was applied by
means of a hydraulic ram and the cells were
crushed until the thickness at the point of
maximum crushing was less than one-fourth of
the original cell thickness. The temperatures on
the exterior surface of the metal cell casing was
monitored by means of an iron-constantan
thermo-couple. The cells were examined after the test for any signs of reaction due to the crushing.
Five fresh Model CR916 cells were used in this
test.
The casings opened and leaked as a
result of this test. There was no temperature
increase or any other adverse reaction as a result
of this test.
Results
Fire Exposure Tests
One sample was placed on a wire screen directly
above a 2 in. diameter laboratory Meker burner
fuelled by methane gas at a pressure of 0.5 psig
and a flow rate of 3.0 ft3/h. The cells were heated
until they exploded or until ultimate results were
obtained. For protection and also to muffle the
sound of any explosions, the cells were tested in a
room separate from the observer. The results of this test were used to determine if further testing
would be needed to evaluate the fire exposure
hazard of these cells. Five fresh cells were used in
this test.
Models 1000-0, 1000-7 and
CR2450N exploded. Based on these results, the
Explosion Test was deemed necessary.
Results
Explosion Test
A cast aluminum chamber, 6 in. in diameter and
12 in. high with a 3/4 in. vent opening, was used
for the test. Iron flanges were attached to both
ends of the chamber. A solid 0.020 in. steel plate
and a second thicker reinforcing steel plate with a
4 in. diameter hole in the center were bolted
together to the bottom flange. Each sample cell
tested was placed in turn in the chamber and
centered on the bottom plate. Steel plates weig-
hing 30 lb. were placed on top of the chamber. A 1-1/2 in. diameter Meker burner was ignited and
placed under the chamber. The chamber
was heated until the test cell exploded. Five Model
1000-0, 1000-7 and CR2450N cells were used in
these tests.
Models 1000-0 and 1000-7 exploded,
however did not lift the lid. Model CR2450N did
not explode, how-ever a fire did occur inside the
explosion chamber.
Results