Page 54 - Battery Reference Book

Effect of cell layout in batteries on battery characteristics 1/39

Table 1.13 Derrionstrating that maximum current is obtained when total internal resistance of battery equals total external resistance
Internal resistance per cell, R, = 0.01 C2
External resistance of battery, R,,t = 0.05 Q
Voltage per cell, E, = 2V
Duration of discharge of each cell, h = 4 h
Number of strings of
cells, n 1 2 3 4 6 8 12 16 24 48
Number of cells in series
per string, m 48 24 16 12 8 6 4 3 2 1
mln 48 12 5.333 3.000 1.330 0.750 0.330 0.190 0.083 0.021
(mln )&(a) 4.800 1.200 0.533 0.300 0.133 0.075 0.033 0.019 0.0083 0.0021
RTOT = (m/n)R, + RCxt 4.850 1.250 0.583 0.350 0.183 0.125 0.083 0.069 0.0583 0.0521
a
(m/n)R,
log (e;) 6 2.66 0.176 -0.180 -0.420 -0.778 -1.377
1.50
0.380
0.167
0.042
-
16
24
0.660
96
Rext
0.05
0.778
0.425
1.982
1.028
1.380
ETOT = mEc 96 48 32 23 16 12 8 6 4 2
Current, [TOT
- mEc
- (A) 19.79 38.40 54.89 68.57 87.43 96.00 96.03 86.95 68.61 38.39
(m/n)R, x Rext
Capacity, CTO.:
3800 3686 3512 3291 2798 2304 1537 1043 549 153
Table 1.14 Effect of cell configuration on e.m.f. and current achieved in arrangements of 48 two-volt cells
Internal resistance per cell, R, = 0.1
External resistance, Rext = 0.05
Voltage per cell, 2V
Number of strings of
cells, n 1 2 3 4 6 8 12 16 24 48
Number of cells in series
per string, m 48 24 16 12 8 6 4 3 2 1
mln 48 12 5.333 3.000 1.330 0.750 0.330 0.190 0.083 0.021
log mln 1.681 1.072 0.727 0.477 0.124 -0.125 -0.523 -0.721 -1.081 -1.678
Current, [TOT
- mE, A
- 19.79 38.40 54.89 68.57 87.43 96.00 96.03 86.95 68.61 38.39
Wr)& + Rext
Totzl resistance, I?,
= (rn/n)R, + Rex 4.850 1.250 0.583 0.350 0.183 0.125 0.083 0.069 0.583 0.0521
Voltage, V = TOT x R 96 48 32 24 16 12 8 6 4 2
Wattage, V x ITOT 1899 1843 1756 1645 1400 1152 768 522 274 76.8
Joule heating
454 440 420 393 335 275 183 124.8 64.9 18.4
Current* as % of I,,
18.8 36.6 52.2 65.3 83.3 91.4 91.4 82.8 65.3 36.6