Voltage of alkaline batteries usually ranges between 1.55 and
1.65 Volt (open circuit voltage (OCV)), whereas 1.5 is consi
de red to be the nominal voltage. The speed of voltage
drop during use is determined by the type of appliance
and the load (drain) which is put onto the battery.
Measuring the OCV of a battery is giving only a very rough and
highly inefficient idea of battery capacity and/or freshness.
The CCV (closed circuit voltage) where for a few seconds a
load (depending on battery size) is put on the battery is giving
a much better view on the status of the measured battery. (If
the voltage is still close to 1.5 the battery is still in relatively
fresh condition, if the voltage is closer to 1.0 V, the battery is
almost at the end of it’s useful life.)
Every kind of appliance needs a minimum voltage to operate
and the level at which the appliance will stop is usually
refered to as the “cut off voltage”. Even if several batteries are
needed to operate an appliance, for battery test purposes the
cut off voltage will be translated as cut off voltage per cell.
(Example: a portable CD player which uses 2 cells and needs
min. 2 volts to operate, so we will say the cut off voltage is
1.0 V per cell.)
is usually expressed in mAh (milli
Ampere hour), whereas the actual drain in combination with
the cut off voltage will determine the capacity in mAh for each
individual use or appliance. It is not as simple as giving only
1 figure to know the actual capacity and/or behaviour of a
battery for different ways of discharge. In order to have
a clear view on battery capacity, one should give specific
parameters at which the batteries can be tested or have a
wider range of different discharge conditions to view the
behaviour of battery performance.
Maximum battery capacity is limited by the weight and
volume of the two main raw materials: zinc and manganese
dioxide. Therefore an LR20 battery will last much longer
than an LR6 battery just because there is much more active
material inside.
Some batteries, like the 9 volt alkaline battery, aredesigned
with 6 cylindrical batteries in series and are spotwelded
together in order to assure a reliable performance during
discharge.
is also important to determine the capacity and
performance of a battery. Alkaline batteries are best suited
to be used in temperature ranges from –10°C to +45°C. In
some cases the batteries can be reliable to deliver small
currents at lower or higher temperatures as well, but this
should be suspect to individual and careful testing. At higher
temperatures the internal resistance of the battery will
increase at a lesser speed, which will provide a better high
drain performance.
As different ways of discharge we mainly consider:
The appliance keeps it’s resistance constant in Ohm
The appliance keeps running on constant drain in A or mA
As the power should remain constant, the drain in Ampère
will increase gradually during discharge as the voltage will
decrease.
For this kind of discharge the increasing internal
resistance towards the end of useful battery life will also
largely determine the actual useful capacity of the batteries.
Total capacity will of course also be strongly influenced by
the cut off voltage.
The various discharge ways (continuous or intermittent) and
loads (light or heavy) determine in a large way the actual
performance one can draw out of a battery.
Shelf life is the ability of batteries to keep more or less the
same performance over a certain period in time. Alkaline
batteries nowadays carry a freshness date of about 5 years
from the moment of production. This means that service
life on a specific discharge compared to a fresh battery
of the same generation is expected to be over 70% versus
initial capacity testing. (If the necessary precautions have
been taken in order to store the batteries in an acceptable
and controlled environment with regard to constant
temperature and humidity.)
The shelf life will be influenced by temperature, humidity and
internal construction:
High temperature & high humidity will speed up the degrada
tion of chemicals which will lead to greater capacity loss at
shorter time.
Poor quality internal construction might also influence the
degradation of chemicals, but mainly as a potential risk for
internal short circuit and leakage over time.
Another, yet more unpredictable factor is the way in which
the electrolyte might cause to deteriorate over time the
nonmetallic parts inside the battery and result in leakage.
Though, there is a very little chance of this happening, it is
always recommended to use up alkaline batteries within the
first half of the expected shelf life.
Panasonic offers a comprehensive family of Alkaline batteries.
This extensive range of products ensures power solutions for
nearly all battery requirements. Whenever your portable device
needs power, You can rely on our high quality battery technology
solutions.
- Smoke detectors
- Marine devices
- Medical torches
- Blood pressure measurements
- Portable audio devices
- High energy flashlights
- Door lock systems
- Scales
- Handheld Meters
- Gas meter devices
- Seismic sensors
- Sanitary devices
- Home monitoring
- Two way radio etc.
Capacity loss estimation at lowmedium drain
20°C
30°C
20°C
30°C
Capacity loss estimation at high drain
%
120
100
80
60
40
20
0
%
120
100
80
60
40
20
0
Fresh 1 Year 2 Years 3 Years 4 Years 5 Years 6 Years 7 Years
Medium drain
Fresh 1 Year 2 Years 3 Years 4 Years 5 Years 6 Years 7 Years
High drain
Various applications can be powered such as: