NETW 1010
Internet of Things:
Batteries
A Short Review
Dr. Eng. Amr T. Abdel-Hamid
Fall 2013
Eradio Calculations
Internet of Things
Eradio = (P(per Bit)* Number of Bits)+ (I sleep* V * T)
Total Energy used for this module
What kind of a battery needed then?!
Dr. Amr Talaat
NETW 1010
Battery (Short Review)
Internet of Things
Duracell batteries
Two cells
9v battery
A real battery
6v dry cell
Another battery
Dr. Amr Talaat
More precisely
NETW 1010
Batteries
Internet of Things
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Dr. Amr Talaat
Cheap
Easy to use
Rechargeable batteries available
Lithium Ion batteries with high capacity
Charging is simple and easy
Size of batteries is a problem
AA battery defines the size of many devices
Environment (temperature) has influence on the capacit
y
NETW 1010
Battery Characteristics
Internet of Things
 Size
 Physical: button, AAA, AA, C, D, ...
 Energy density (watts per gram or cm3)
 Longevity
 Capacity (Ah, for drain of C/10 at 20°C)
 Number of recharge cycles
 Discharge characteristics (voltage drop)
Dr. Amr Talaat
NETW 1010
Further Characteristics
Internet of Things
 Cost
 Behavioral factors
 Temperature range (storage, operation)
 Self discharge
 Memory effect
 Environmental factors
 Leakage, gassing, toxicity
 Shock resistance
Dr. Amr Talaat
NETW 1010
Battery Organization
Internet of Things
Dr. Amr Talaat
NETW 1010
Battery Connections
Internet of Things
Dr. Amr Talaat
NETW 1010
Primary (Disposable) Batteries
Internet of Things
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Zinc carbon (flashlights, toys)
Heavy duty zinc chloride (radios, recorders)
Alkaline (all of the above)
Lithium (photoflash)
Silver, mercury oxide (hearing aid, watches)
Zinc air
Dr. Amr Talaat
NETW 1010
Alkaline Battery Discharge
Internet of Things
Dr. Amr Talaat
NETW 1010
Secondary (Rechargeable) Batteries
Internet of Things
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Nickel cadmium
Nickel metal hydride
Alkaline
Lithium ion
Lithium ion polymer
Lead acid
Dr. Amr Talaat
NETW 1010
Nickel Cadmium Batteries
Internet of Things
 Chemistry
Cadmium (-), nickel hydroxide (+)
Potassium hydroxide aqueous electrolyte
 Features
+ Rugged, long life, economical
+ Good high discharge rate (for power tools)
 Relatively low energy density
 Toxic
Dr. Amr Talaat
NETW 1010
NiCd Recharging
Internet of Things
 Over 1000 cycles (if properly maintained)
 Fast, simple charge (even after long storage)
C/3 to 4C with temperature monitoring
 Self discharge
10% in first day, then 10%/mo
Trickle charge (C/16) will maintain charge
 Memory effect (Medium Effect over time)
Dr. Amr Talaat
NETW 1010
NiCd Memory Effect
Internet of Things
Dr. Amr Talaat
NETW 1010
NiMH Battery Discharge
Internet of Things
Dr. Amr Talaat
NETW 1010
NiMH Recharging
Internet of Things
 Less prone to memory than NiCd
 Shallow discharge better than deep
Degrades after 200-300 deep cycles
Need regular full discharge to avoid crystals
 Self discharge 1.5-2.0 more than NiCd
 Longer charge time than for NiCd
To avoid overheating
Dr. Amr Talaat
NETW 1010
NiCd v NiMH Self-Discharge
Internet of Things
Dr. Amr Talaat
NETW 1010
Secondary Alkaline Batteries
Internet of Things
 Features
 50 cycles at 50% discharge
 No memory effect
 Shallow discharge better than deeper
Dr. Amr Talaat
NETW 1010
NiCd v Alkaline Discharge
Internet of Things
Dr. Amr Talaat
NETW 1010
Lithium Ion Batteries
Internet of Things
 Chemistry
Graphite (-), cobalt or manganese (+)
Nonaqueous electrolyte
 Features
+ 40% more capacity than NiCd
+ Flat discharge (like NiCd)
+ Self-discharge 50% less than NiCd
 Expensive
Dr. Amr Talaat
NETW 1010
Lithium Ion Recharging
Internet of Things
 300 cycles
 50% capacity at 500 cycles
Dr. Amr Talaat
NETW 1010
Lithium Ion Polymer Batteries
Internet of Things
 Chemistry
Graphite (-), cobalt or manganese (+)
Nonaqueous electrolyte
 Features
+ Slim geometry, flexible shape, light weight
+ Potentially lower cost (but currently expensive)
+ Higher discharge
 Lower energy density, fewer cycles than Li-ion
Dr. Amr Talaat
NETW 1010
Battery Capacity
Internet of Things
Type
Dr. Amr Talaat
Capacity
(mAh)
2850
Density
(mWh/g)
124
1600
80
NiCd AA
750
41
NiMH AA
1100
51
Lithium ion
1200
100
Lead acid
2000
30
Alkaline AA
Rechargeable
NETW 1010
Discharge Rates
Internet of Things
Type
Alkaline
Voltage
Peak Optimal
Drain
Drain
1.5 0.5C < 0.2C
Dr. Amr Talaat
NiCd
1.25
20C
1C
Nickel metal
1.25
5C
< 0.5C
2
5C
0.2C
3.6
2C
< 1C
Lead acid
Lithium ion
NETW 1010
Recharging
Internet of Things
Type
Alkaline
NiCd
Cycles Charge Discharge Cost per
(to 80%)
time per month
kWh
50 (50%) 3-10h
0.3% $95.00
Dr. Amr Talaat
1500
1h
20%
$7.50
NiMH
300-500
2-4h
30%
$18.50
Li-ion
500-1000
2-4h
10%
$24.00
300-500
2-4h
10%
Lead acid 200-2000
8-16h
5%
Polymer
$8.50
NETW 1010
Energy harvesting
Internet of Things
Dr. Amr Talaat
 Capacity of battery limits the lifetime of the device
 Battery depletion -> Device cannot work -> (Sensor) network cann
ot work
 Idea: recharge the batteries during operation
 Use energy from the environment
 Current approaches
 Photovoltaics: Solar modules for sensor nodes
 Thermoelectric generators
 Conversion of temperature differences to energy
 Kinetic energy conversion
 Piezo-electric principle already tested for shoes
 MEMS gas turbines
 Convert air- or fluid streams
NETW 1010