Page 61 - Battery Reference Book

1/46 Introduction to battery technology
to select the desired combination of the various para- Capacity (Ah)
meters that would be required in battery service. X
Figures 1.27 - 1.29 illustrate the interrelationship of 26
discharge time with discharge current, end-point e.m.f.,
Ah capacity and energy density. Thus, if 2min and 1 6oo
30 min discharges are adopted, the effect of this on the - 500 -
a
above parameters would be as illustrated in Table 1.2 1. - 400 E
I
Information of this kind enables trade-offs to be made discharge current 430 A, E!
in the various aspects of battery performance. 2.4 min discharge - 300 2
Another aspect of battery performance can be stud- 10 - 200 ;
P
ied by preparing plots of discharge current against 8
end-point e.m.f. and electrical resistance (Figure 1.30) 6
and Ah capacity and energy density (Figure 1.31). , - 100
Again considering the effect of carrying out the
discharge at two different currents lOOA and 600A 0 4 8 12 16 20 24 28
on battery operating parameters, we have the effects Discharge time (min)
illustrated in Table 1.22.
Figure 1.25 2V lead-acid battery: relationship of discharge time
with Ah capacity and current

30
0.03 r Resistance /
24
1600
- 500 2
'ii 16
I
14 -400 E
0 12 t
10 - 300 $
:
-200 5
6
- 100
0 2 4 6 8 10 12 14 16 18 20
Discharge rate (X C\ 0
0 4 8 12 16 20 24 28
Figure 1.23 2V lead-acid battery: influence of discharge rate on Discharge time (min)
capacity
Figure 1.26 2 V lead-acid battery: relationship of discharge time
with electrical resistance and discharge current

-600
--x-X
- 500 -
Optimum 430 A at 1.44 V, a - 500
I 4
-400 '$ I
E - 400 E
3 E
-300 - 300 $
F
P
-200 $ - 200 ;
.-
n Y)
Current - 100 - 100 6
0
1 . 0 3 10 -0
0 4 8 12 16 20 24 28
Discharge time (min) Discharge time (rnin)
Figure 1.24 2V lead-acid battery: relationships of discharge time Figure 1.27 2V lead-acid battery: relationship of discharge time
with end-point e.m.f. and discharge current with energy density and discharge current