Environmental Engineering Reference
In-Depth Information
Electrochemical
storage
1,000
NaS
Li ion
Pb-acid
100
10
Ultra-capacitor
1
2,700 F, 2.5 V
0.1
Film capacitor
0.01
10
100
1,000
10,000
Power density (W/kg)
Figure 10.22 Ragone plot of energy storage systems
constant power discharge experiment. Figure 10.22 is a Ragone plot for some
representative ESS.
Empirical specific energy density versus specific power density trend lines are
depicted in Figure 10.22 for various energy storage technologies. These trends
have been characterized in the laboratory and derived from constant power test data.
The following set of equations gives energy density,
g
E
, as a function of power
density,
g
P
, which will be useful in sizing operations to be described later. The trend
line data fit consists of two parameters:
k
1
the high power rate discharge test and
k
2
the slope derived from high minus low power rate test data:
g
E
¼
k
1
k
2
g
P
ð
10
:
26
Þ
For a sodium-sulphur advanced battery system (flow type battery [6]):
g
E
¼
130
0
:
034
g
P
ð
10
:
27
Þ
For a lithium ion battery system:
g
E
¼
75
0
:
025
g
P
ð
10
:
28
Þ
For an NiMH battery system:
g
E
¼
50
0
:
035
g
P
ð
10
:
29
Þ
For a lead-acid battery system, assuming valve regulated technology:
g
E
¼
50
0
:
2
g
P
ð
10
:
30
Þ
