Biomedical Engineering Reference
In-Depth Information
batteries are the most common approach, they are discussed in terms of
capacity and service life.
Battery capacity is usually expressed in terms of energy in Joules (J)
or more commonly in watt-hours (Wh). Power is the rate of energy use
(energy/time, where time is expressed in seconds), watt-hours or more
commonly kilowatt-hours (kWh, 1,000 Wh
5
1 kW) is a unit of energy
(for instance, 10 h of regular use of a home appliance rated at 1,500 W
will consume 15,000 Wh or 1.5 kWh). Batteries are also rated for spe-
cific energy (energy/mass or Wh/kg) or energy density (energy/volume
or Wh/L), the amount of energy available per mass or per volume
depending on the intended application.
Table 2.2
summarizes the bat-
tery ratings of primary cells (disposable batteries), while
Table 2.3
summarizes the ratings for secondary cells (rechargeable batteries).
The nominal voltage depends exclusively on the chemical reactions of
its components. Common types of batteries are the zinc
carbon and
alkaline (sizes AAA, AA, C, D, 9V), as well as zinc
air and
Table 2.2 Ratings of Primary Cells (Disposable Batteries)
Battery Type
Specific Energy
(Wh/kg)
Energy Density
(Wh/L)
Nominal
Voltage (V)
Service Life
Zinc
carbon (Zn/C)
36
60
120
1.5
2 years
Alkaline (zinc
manganese
dioxide, Zn/MnO
2
)
110
210
320
1.5
7 years
Zinc
air (Zn
air)
470
1480
1.35
1.65
3 years shelf life;
3
12 weeks use
Silver-oxide (silver
zinc)
130
500
1.55
5 years
Lithium (lithium
manganese
330
550
650
2.8
5 years
dioxide, LiMnO
2
)
Lithium (lithium-thionyl
chloride, LiSOCl
2
)
760
800
1420
3.6
10
20 years
Lithium (lithium
iodine,
Li
I
2
)
150
250
900
2.8
10 years
Lithium (lithium
silver
150
410
2.75
6 years
vanadium oxide,
Li
Ag
2
V
4
O
11
,Li
SVO)
Adams (1995)
Drews et al. (2001)
Chen et al. (2006)
