Post on 31-Mar-2015
ZINC AIR BATTERIES
By: Ana Brar
GENERAL INFORMATION Activated when oxygen is
absorbed into the electrolyte through a membrane
Usually reaches full operating voltage within 5 seconds of being exposed to air
Oxygen diffused directly into battery
Electrolyte that catalytically promotes the reaction of oxygen, but is not depleted or transformed at discharge
Oxygen from air
Zinc and alkaline electrolyte
Button cell
ADVANTAGES Weight - not necessary to carry a second
reactant High energy density Competitive with Lithium-ion Inexpensive materials Flat discharge voltage Safety - don't require volatile materials, so zinc-
air batteries are not prone to catching fire like lithium-ion batteries
Excellent shelf life, with a self-discharge rate of only 2% per year
Available in a range of button and coin cell sizes Rechargeable high power fuel cells in the
process of development Environmental benefits Have high volumetric energy density compared
to most primary batteries
DISADVANTAGES Sensitive to extreme temperature and humid
conditions Carbon dioxide from the air forms carbonate
which reduces conductivity High self discharge (after seal is broken) After activation, chemicals tend to dry out and
the batteries have to be used quickly Although recharging is possible for fuel cells, it’s
also inconvenient and is only suitable for high power types
Zinc air batteries must be larger to satisfy high current needs
High power batteries use mechanical charging in which discharged zinc cartridges are replaced by fresh zinc cartridges—therefore the used cartridges must be recycled
Have flooding potential Limited output When zinc turns it into zinc oxide it expands,
space
COMMON USES Hearing Aids Watches Mobile phones Digital Cameras Pagers Power sources for electric fences Recharging Li-Ion batteries Transportation:
Cars - EVsBuses
RECHARGEABILITY Zn/Air Batteries – not rechargeable Zn/Air Fuel Cells – rechargeable ReVolt has developed rechargeable
Zinc/Air batteries In future: EVs using Zn/Air? Zinc-air batteries can be made for high
rate applications, which have a short life but high output
Or low rate, with low power but last a longer amount of time
TRANSPORTATION Would use Zn/Air Fuel Cells Currently used in Las Vegas Electrical Vehicle Division Contain a central static
replaceable anode cassette To refuel: discharged
zinc-air module removed from the vehicle and is "refueled" by exchanging spent "cassettes" with fresh cassettes Regeneration
REVOLT Swiss Company Opened U.S. center of operations -
PortlandDisadvantages: • They can't deliver sufficient
power• They lose a lot of power very
quickly• The cell dry out, becoming
useless after only a few months
• There is no satisfactory way to recharge them
The solution: • ReVolt's new technology
has a theoretical potential of up to 4x the energy density of Li-Ion batteries at a comparable or lower production cost
• Extended battery life due to stable reaction zone, low rates of dry-out and flooding, and no pressure build-up problems
• Rechargeability• Compact size• Can manage the humidity
within the cell
MORE ON REVOLT ReVolt technology claims to have
overcome the main problem with zinc-air rechargeable batteries--that they typically stop working after relatively few charges (air electrode can become deactivated)
For electric vehicles: plan to use two flat electrodes – one containing zinc “slurry”
Air electrodes in the form of tubes Zinc slurry is pumped through the tubes
where it's oxidized, forming zinc oxide and releasing electrons
REVOLT’S EV BATTERY Plan to increase energy density by
increasing the amount of zinc slurry relative to the amount of material in the air electrode
Much like a fuel cell system or conventional engine – zinc slurry ~ fuel, pumping through the air electrode like gas in a combustion engine
Longer life span - from 2,000 to 10,000 cycles
As with fuel cells, may need to be paired with another type of battery for bursts of acceleration or regenerative braking
ZN/AIR VS. AL/AIR Al/Air: produces electricity from the
reaction of oxygen in the air with aluminum
Has one of the highest energy densities of all batteries
Not widely used - cost, shelf-life, start-up time and byproduct removal, which have restricted their use to mainly military applications
An electric vehicle with aluminum batteries could have potentially ten to fifteen times the range of lead-acid batteries with a far smaller total weight
MG/AIR LI/AIR High energy
density Safe Inexpensive Not been widely
used - self-discharge in neutral solution
Reaction mechanism of magnesium alloy anode
Effects of different additives on performance of Mg alloy in solution
Approach energy density of fuel cells
PolyPlus Single use and
rechargeable lithium metal-air – could power Evs
Theoretically: max energy density 5,000+ watt-hours per kilogram
Lower self discharge rate and longer shelf life
CONCLUSION Many promising metal-air batteries:
Zinc/AirAluminum/AirMagnesium/AirLithium/Air
Still mostly in developmental stages Hope for use in electric vehicles in the
future
REFERENCES http://news.cnet.com/8301-11128_3-10388553-54.ht
ml http://www.technologyreview.com/energy/22926/ http://www.treehugger.com/files/2009/10/zinc-air-bat
tery-revolt-3-times-more-energy-lithium-ion-battery-electric-cars.php
http://www.mpoweruk.com/zinc_air.htm http://news.cnet.com/8301-11128_3-10388553-54.ht
ml
http://www.duracell.com/oem/primary/Zinc/zinc_air_tech.asp
http://www.revolttechnology.com/technology/revolt-introduction.php
http://www.technologyreview.com/business/23812/page2/