Zinc Air Batteries - PowerPoint Presentation

Slide1

Zinc Air Batteries

By: Ana BrarSlide2

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 airOxygen diffused directly into batteryElectrolyte that catalytically promotes the reaction of oxygen, but is not depleted or transformed at discharge

Oxygen from air

Zinc and alkaline electrolyte

Button cellSlide3

Advantages

Weight - not necessary to carry a second reactant

High energy densityCompetitive 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 sizesRechargeable high power fuel

cells in the process of development Environmental benefits

Have high volumetric energy density compared to most primary batteries Slide4

Disadvantages

Sensitive to extreme temperature and humid conditions

Carbon dioxide from the air forms carbonate which reduces conductivityHigh 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 outputWhen zinc turns it into zinc oxide it expands, spaceSlide5

Common uses

Hearing Aids

WatchesMobile phonesDigital CamerasPagersPower sources for electric fences

Recharging Li-Ion batteries

Transportation:

Cars - EVs

BusesSlide6

Rechargeability

Zn/Air Batteries – not rechargeable

Zn/Air Fuel Cells – rechargeableReVolt has developed rechargeable Zinc/Air batteriesIn 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 timeSlide7

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

RegenerationSlide8

Revolt

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 problemsRechargeabilityCompact

sizeCan manage the humidity within the cellSlide9

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 electronsSlide10

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 engineLonger life span - from 2,000 to 10,000 cyclesAs with fuel cells, may need to be paired with another type of battery for bursts of acceleration or regenerative braking Slide11

Zn/air vs. al/air

Al/Air: produces electricity from the reaction of oxygen in the air with aluminumHas 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 applicationsAn electric vehicle with aluminum batteries could have potentially ten to fifteen times the range of lead-acid batteries with a far smaller total weightSlide12

Mg/air Li/Air

High energy density

SafeInexpensiveNot been widely used - self-discharge in neutral solutionReaction mechanism of magnesium alloy anodeEffects 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 lifeSlide13

conclusion

Many promising metal-air batteries:

Zinc/AirAluminum/AirMagnesium/AirLithium/AirStill mostly in developmental stages

Hope for use in electric vehicles in the futureSlide14

References

http://news.cnet.com/8301-11128_3-10388553-54.html

http://www.technologyreview.com/energy/22926/http://www.treehugger.com/files/2009/10/zinc-air-battery-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.html

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/