Transcript Battery Types - Solon City Schools

Batteries
Physics
Power Cell
 Device
for storing chemical
energy and then releasing it
in the form of electricity
when current is needed
Battery
More
than
one power
cell working
together
9 V battery
Inside a 9 V are
6-1.5 V power
cells connected
in a row.
Parts of a Power Cell
1. Anode
– Metal
– High affinity for oxygen
– Draw oxygen from cathode
to become oxidized
Parts of a Cell
2. Cathode
– Metallic oxide
– Lower affinity for oxygen
– Becomes reduced when
oxygen is taken
Parts of a Cell
3.Separator
– Insulator
– Keeps cathode
separated from anode to
control reaction
Parts of a Cell
4.Current Collector
– Connected to anode and cathode
– Good conductor
5.Electrolyte
– Usually liquid (ionized water, acid/base)
– “Domino Effect” of oxygen from cathode
to anode
Operation of Power Cell
 As
anode becomes oxidized, an
electron must be given up
 Electron flows through anode’s
current collector  through circuit
(outside of battery) as electrical
current  back to cathode’s
current collector
Carbon-Zinc (C-Zn)
1.5
volts
Works well if using 100 mA or
less
Low capacity
3 year shelf life
anode and
anode collector
Cathode collector
MnO2
NH4Cl
ZnCl2
Alkaline
 1.5
V: lose voltage gradually
 High Capacity (electrical energy)
– Last
5
longer
year shelf-life
 Better in high drain devices than
C-Zn
steel
MnO2, graphite
Electrolyte
KOH
Zn powder
Metal nail
Lithium
 Started
off as button cell
 Anode: lithium
 Cathode: magnesium dioxide
 3 V: Takes up less space with
more voltage
Lithium
High
Capacity
Low Drain Rate
Toxic: Special disposal
Light Weight
Button Cell
 Anode:
Zinc or Lithium
 Cathode: Silver or Mercury
Oxide
 Compact
 Large Life
Recharging Batteries
A
current from an outside
source is pushed through the
cell in the opposite direction
from the original current
 Oxygen goes from anode to
cathode
Nickel-Cadmium (Ni-Cd)
 1.2
Volts
 Low capacity
 Memory effect (Rechargeable)
– If you re-charge the battery
too soon, you lower its
capacity
Nickel-Metal Hydride
(NiMH)
1.2
V
Best rechargeable battery
High Capacity
Good for high drainage
devices
Lithium-Ion
 3.6
V
 Slow-loss of charge (5% per month)
 Best energy to weight ratio
 No memory effect
 Popular
for portable electronics
(cell phones, IPod)
Ideal Power Cell
 Unlimited
shelf life
 Maximum energy for minimum
space
 Light weight
 Rechargeable (fast and
complete)
Ideal Power Cell (cont.)
 Consumer
proof/Safe
 Resistant to environmental
extremes
 Cost
 Perform in a variety of different
applications
Diode
Made of semi-conducting material
 Only permits current to pass in one
direction
 L.E.D.: light emitting diode
– Longer leg must be connected to
positive side of circuit (cathode)
