Renata SA 3V Lithium Coin Cells - DESIGNER'S GUIDE - Manual (Page 44)

Influence of temperature on electrical performance
Frequently Asked Questions (FAQ)
The operating temperatures of lithium coin cells
are given on page 7. Below –30°C the pulse
current performance of the cells is significantly
reduced, due to the increased internal resistance.
Ambient temperatures over the given max.
operating temperature may be possible for a short
period of time. Please ask Renata experts for
advice on this matter.
Has high temperature any detrimental
effect on the cell performance?
Increasing temperature to values above room
temperature will increase the rate of self-
discharge, reducing the available cell capacity –
thus shortening both the service-life and the
shelf-life. The self-discharge of a cell is due to
parasitic reactions taking place at the electrodes,
consuming the electroactive material. As for every
reaction, the rate of these processes is function of
temperature. A simple "rule of thumb" to
determine the self-discharge at a given
temperature is the following: the rate of self-
discharge increases of a factor 2 for every 10
degrees Celsius of temperature increase from
room temperature (20°C). Given that at room
temperature the rate of self-discharge of lithium
coin cells is 1% of capacity loss per year, at 40°C
(for example) the self-discharge rate will be:
1% x 2 (40-20)/10 = 1% x 2 2 = 4% of capacity
loss/year.
In addition to self-discharge considerations, the
maximum storing and operating temperature for
the lithium coin cells must not exceed the given
max. operating temperature, in order to avoid any
electrolyte leakages, leading to reductions of cell
functionality.
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Has low temperature any detrimental
effect on the cell performance?
Generally speaking, the performances of a cell at
low temperature are reduced because of the
decreased conductivity of the electrolyte, which
leads to an increase of internal resistance. As a consequence, the ability of the cell to deliver high
power is reduced. Especially when designing an
application with high power demand (high current
consumption, like pulse-loads), this factor must be
carefully taken into account.
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Characteristics
Shelf life (temperature / time)
Storage characteristics (CR2430)
Storage time (years)
Vo
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0.1 0.2 0.3 0.5 1 2 3 5 10
Time (h)
0 200 400 600 800 1000
R
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c
ap
ac
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(
%
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100
80
60
40
20
0
3.5
3
2.5
2
1.5
1
0.5
0
A
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3
m
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s
st
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at
8
0
°C
Fr
es
h
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ll
Vo
lta
ge
(
V
)
Time (h)
0 200 400 600 800 1000
3.5
3
2.5
2
1.5
1
0.5
0
A
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1
y
ea
r
st
or
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at
6
0
°C
Fr
es
h
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ll
Vo
lta
ge
(
V
)
Time (h)
0 200 400 600 800 1000
3.5
3
2.5
2
1.5
1
0.5
0
80°C 60°C 45°C 23°C
8.25 k ⏲
8.25 k ⏲
8.25 k ⏲