How to power your
smartphone for a
week!
What is a battery?
• A device that stores chemical energy in
its active materials and converts it, on
demand, into electrical energy by
means of an electrochemical reaction
-
+
Electron flow
Ion
flow
Cathode
• Batteries are made up of one or more
basic electrochemical units called
cells.
Anode
– Electrochemical reaction is a chemical
reaction involving the transfer of
electrons
– Cells are usually connected in series
to increase the voltage.
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Sentech
Electrolyte
Types of batteries
• Primary batteries are used once and thrown
away, like the alkaline batteries used in
portable CD players
– Electrochemical reactions are not reversible
and active materials cannot be restored to
their original state.
Primary
34%
Secondary
66%
• Secondary (or rechargeable) batteries can be
used many times, like the battery in cell
phones and laptop computers
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Sentech
– The electrochemical reactions are reversible,
and the active materials can be restored to
their original chemical composition.
Widely used rechargeable batteries
Market share
• Lead acid (30-40 Wh/kg, 70-92% eff., 2V)
–
Over 100 years old, and still the most widely used
rechargeable battery in the world.
51%
• Nickel metal hydride (30-80 Wh/kg, 66% eff., 1.2 V)
–
A high power battery chemistry similar to nickel cadmium,
introduced in the 1980s. It is environmentally friendly,
contains no toxic cadmium, and is replacing NiCd in many
applications.
8%
• Lithium ion (160 Wh/kg, 99.9% eff., 3.6-3.7V)
The newest and fastest growing rechargeable battery
technology.
–
Theoretical capacity: 150-275mAh/g
Main concerns: large volumes, liquid
technology, leakage, and toxicity
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31%
Sentech, Wikipedia
–
Real batteries
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Research batteries at ORNL
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Actual technology and materials
Li-Air
Li-S
New chemistries
Pb Acid
Spiral
Wound
Emergency
Aircraft
10000
Where we
need to
Aircraft
go
FCS
Weapons
1000
Vehicle
Mobility
SLI
100
Commercial
Hybrids
BA5590 Soldier Apps
Soldier
Underwater
10
Where we
are today
1
0
20
40
60
80
100
120
140
160
180
Specific Energy, Wh/kg
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BA5347 & BA5123
Soldier Apps
© Ming Au, SRNL
Specific Power, W/kg
100000
200
220
240
Cell potential
© pinkmonkey.com
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© Maxim Integrated Products
Cell capacity
It C
F    N Ae
n n
zF
C
M
LiC 6  Li   1e   C6
Li22 Si5  22 Li   22e   Si5
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z  1; M (C )  6 12.01
 C  0.372
g
mol
Ah
g
z  22; M ( Si )  5  28.09
 C  4.200
Ah
g
g
mol
Cell energy
• Capacity x voltage
Overcharge
• Cut off voltage is
controlling available
energy but also
limiting access for
safe operation
Overdischarge
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Lithium ion battery principle
Discharge
reaction:
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Cathode
Anode
Li+ + e- + MeO2 → LiMeO2
LiC6 → Li+ + e- + C6
Development targets and accomplishments
Plug-in Hybrid electric
vehicles (PHEV)
Hybrid electric
vehicles (HEV)
• D. Howell, Energy Storage Research and Development, Annual
Progress Report 2006
• FreedomCAR and Fuel Partnership and United States Advanced
Battery Consortium, Electrochemical Energy Storage Technical
Team Technology Development Roadmap (Southfield, MI:
USCAR, 2006).
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Fruit battery – Natural galvanic
element
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Have fun and stay safe!
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