Transcript Zn/air final

By: Ana Brar
Oxygen from air
 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
Zinc and alkaline
electrolyte
Button cell
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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 lithiumion 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
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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
 Hearing
Aids
 Watches
 Mobile phones
 Digital Cameras
 Pagers
 Power sources for electric fences
 Recharging Li-Ion batteries
 Transportation:
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Cars - EVs
Buses
 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
 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
 Swiss
Company
 Opened U.S. center of operations - Portland
Disadvantages:
•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
 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
 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
 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
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
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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
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promising metal-air batteries:
Zinc/Air
Aluminum/Air
Magnesium/Air
Lithium/Air
 Still
mostly in developmental stages
 Hope for use in electric vehicles in the future
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http://news.cnet.com/8301-11128_3-10388553-54.html
http://www.technologyreview.com/energy/22926/
http://www.treehugger.com/files/2009/10/zinc-airbattery-revolt-3-times-more-energy-lithium-ion-batteryelectric-cars.php
http://www.mpoweruk.com/zinc_air.htm
http://news.cnet.com/8301-11128_3-10388553-54.html
http://www.duracell.com/oem/primary/Zinc/zinc_air_tec
h.asp
http://www.revolttechnology.com/technology/revoltintroduction.php
http://www.technologyreview.com/business/23812/page2
/