Environmental Engineering Reference
In-Depth Information
Source:
Gretsch, 1978
Figure 4.44
Gretsch Equivalent Circuit of a Lead-Acid Battery
Figure 4.44 shows the
equivalent circuit
for one cell of a lead-acid battery.
Most of the resistances of the equivalent circuit depend on temperature
ϑ
,
state of charge
SOC
and the battery current
I
. The equation
(SOC)
(4.97)
considers these influences.
R
0
is a constant base resistance that is modified by
the three factors r depending on the operating conditions.
Table 4.10 describes the different elements of the equivalent circuit.
Gretsch has found the parameters
L
= 1-10
µ
H,
R
I0
= 50 m
Ω
,
R
P
=1.4
Ω
,
C
P
=1
µ
F,
R
G0
= 765 m
Ω
,
V
G
= 2.4 V,
R
S
=5-10kW,
R
DC0
=25m
Ω
,
Table 4.10
Elements of the Lead-Acid Battery Equivalent Circuit
Symbol
Component
Chemical-physical description
L
Inductance
Filamentary current separation across
plates
R
I
Transient internal resistance
Metallic and ionic conductance
R
P
Polarization resistance
Re-orientation losses of dissociation
product
C
P
Polarization capacity
Displacement current without chemical
conversion
R
G
Gassing resistance
Inhibition of water decomposition
V
G
Gassing voltage
Start of water decomposition
R
S
Self-discharge resistance
Minor reaction, soiling
R
DC
Discharge conversion
Inhibition of forming PbSO
4
resistance
R
CC
Charge conversion resistance
Inhibition of dissolving PbSO
4
R
DD
Discharge diffusion resistance Acid concentration gradient
R
CD
Charge diffusion resistance
Acid concentration gradient
C
W
Work capacity
Direct convertible acid volume in pores
C
R
Rest capacity
Acid volume between plates, convertible
mass
