Consumer Batteries
Derrick Chou
Derek Juang
Jed Kim
Julia Wang
EE164, Fall 2002: with Dr. Ybarra
Chemistry of Batteries
• Galvanic Cells
• Daniell Cell
• Rechargeable
Batteries
Nickel Cadmium(NiCd)
• NiCd batteries are the most commonly used
rechargeable batteries
• Used where long life, high discharge rate and
economical price are important
• Cadmium anode, nickel-hydroxide cathode,
alkaline electrolyte
• High currents at relatively constant voltage
• Low capacity (450-900 mAh)
• Low energy density (40-60 Wh/kg)
• Low shelf life, discharges quickly (20% per month)
• High cycle life (1550)
• Moderate overcharge tolerance
• Very sensitive to memory effect
• Low cost
• Contains toxic material, need special disposal
http://http://www.nlectc.org/txtfiles/batteryguide/ba-type.htm
Nickel Metal Hydride (NiMH)
• Provides incremental improvements in capacity
over the NICAD at the expense of reduced
cycle life and lower load current
• Hydrogen storage metal alloy anode, nickel
oxide cathode, potassium hydroxide electrolyte
• 30-40% greater capacity than NiCd
(1100-1600 mAh)
• Moderate energy density (60-80 Wh/kg)
• Low shelf life, discharges quickly (30% per month)
• High cycle life (500-600)
• Low overcharge tolerance
• Moderate cost
Lithium Ion (Li Ion)
• Fragile technology requiring protector circuit for
overcharge (when charged, voltage still rises)
• Used where very high energy density is needed
and cost is secondary
• High capacity(50% more than NiCd)
• Light weight (20-35% less than NiMH)
• Long shelf life (won’t discharge)
• Memory-effect resistant
• Expensive
• Lifespan is 12-18 months
• Environmentally Friendly
Lithium Polymer (Li Poly)
• Most advanced battery technology
• Only hybrid versions are available in today’s
market
• More resistant to overcharge (less chance
for electrolyte leakage)
• Currently no cost advantage over Li Ion, but potential for
lower cost
• Can be made into any shape, any size (ultra slim
geometry for cell phones)
Rechargeable Battery Comparison
NICAD NiMH Li-Ion Li-Polymer Reusable Alkaline
Energy Density (Wh/kg) 40-60 60-80 100 150-200 80 (initial)
Capacity (mAh) 450-900 1100-1600 750+ 1800
Cycle Life
(capacity decrease from 100% to 80%)
1550 500 500-1000 100-150 10 (to 65%)
Fast charge time 1-1h 2-4h 3-4h 8-15h 2-3h
Overcharge tolerance moderate low very low N/A moderate
Self-discharge per month
20% 30% 10% N/A 0.30%
(room temperature)
Cell voltage
(nominal)
1.25V 1.25V 3.6V 2.7V 1.5V
040º to -20º to +60º -20º to
Operating Temperature N/A 0º to +65º C
+60º C C +60º C
Maintenance requirement
30 days 90 days not req. not req. not req.
(to obtain max. service life)
Typical Battery Cost
$50.00 $70.00 $100.00 $90.00 $5.00
(Cost by US prices)
In commercial use since 1950 1990 1997 Not released 1992
http://www.computerhope.com/battery.htm
Rechargeable Battery Qualitative Comparison
Attribute Ni-Cd Ni-MH Li-Ion Li Polymer
Energy Density Low Medium High High
Energy Storage Low Medium Medium Medium
Cycle Life High High High High
Cost Low Medium High High
Safety High High Medium High
Environment Low Medium Medium Medium
Lead Batteries
• The battery industry is the largest consumer of lead in the
world.
• 98 percent of a lead battery is recyclable.
• Lead emissions from battery manufacturing account for
less than one percent of the country's total estimated
lead emissions, even though battery manufacturing
accounts for more than 80 percent of lead usage in the country.
• Body takes in lead in two ways:
– 1. Ingestion
– 2. Inhalation
Recycling Chart
2002 Battery Council International
Lead Acid Battery
• Closed Loop Life Cycle
– 60 to 80 percent recycled lead and
plastic
• Indefinite Cycle
Recycling Process
• Hammermill breaks it apart.
• Plastic – melt then make small pellets.
• Lead – melt and remove impurities.
• Sulfuric Acid
– 1. Neutralized
– 2. Convert to Sodium Sulfate
Federal Hazardous Waste
Requirement
• Ignitability, Corrosivity, Reactivity,
Toxicity.
• Hazardous if one or more of the above
characteristics are present.
RBRC
• Rechargeable Batteries Recycling
Corporation
• Nickel Cadmium (Ni-Cd)
• Nickel Metal Hydride (Ni-MH)
• Lithium Ion (Li-ion)
• Small Sealed Lead (Pb)*
Nickel-Cadmium
• Highly toxic, carcinogenic
• Can accumulate up marine food webs
• Therefore affect people who eat seafood
• It may lead to potentially fatal kidney and liver
problems, brittle bones, and reproductive
disorders
Lithium Ion/Lithium Polymer
• Completely discharged lithium batteries
can be safely disposed of in the landfills.
Beyond Batteries
• Fuel Cells (Micro-Fuel Cells)
– Endlessly Rechargable
– Hydrogen reacting with oxygen in air
– Water as waste product