rechargeable batteries with conductive polymer
TRANSCRIPT
Rechargeable Batteries
Presented byDevansh GuptaM.Sc Polymer
ScienceSemester 1
Contents IntroductionWhy Do We Need Batteries?Electrodes & ElectrolytesBrief History About BatteriesTypes Of BatteryWhat If We Use Conducting
Polymer In Rechargeable Batteries
Safety Issues Reference
IntroductionBattery Is Nothing But A Device Which
Converts Stored Chemical Energy Into Electrical Energy.
It Is Made Up Of Two Electrodes (Anode & Cathode) And Electrolyte Solution.
Here Oxidation & Reduction Reactions Are Simultaneously Happens Between These Two Electrodes, Which Create The Current Flow.
When A Battery Is Supplying Current, It’s +Ve Terminal Is Denoted As ‘Cathode’ & It’s –Ve Terminal Is Denoted As ‘Anode’ Symbol of battery
in a circuit diagram
Why Do We Need Batteries?
4
Electrodes & ElectrolytesCathode– Positive terminal – Electrochemical reduction occurs (gain electrons)
Anode– Negative terminal– Electrochemical oxidation occurs (lose electrons)
Electrolytes – Allow Ions to move between electrodes and
terminals– Allows Current to flow out of the battery to
perform work
Brief History About Batteries
In 1749, Benjamin Franklin first used the term “battery” to describe a set of linked capacitors he used for his experiments with electricity.
In 1800, Alessandro Volta invented the first true battery, which came to know as the voltaic pile.
The voltaic pile consist a pair of silver and zinc discs placed on each other which is separated by a layer of cloth soaked in brine (Brine as Electrolyte) Unlike the Leyden Jar, the voltaic pile produced a stable & continuous current, and lost little charge over time when not in use.
Early models of voltaic pile can’t produce strong current to generate sparks.
C o n t i n u e d
1800 Voltaic Pile: Silver Zinc1836 Daniell Cell: Copper Zinc1859 Planté: Rechargeable Lead-acid Cell1868 Leclanché: Carbon Zinc Wet Cell1888 Gassner: Carbon Zinc Dry Cell1898 Commercial Flashlight, D Cell1899 Junger: Nickel Cadmium Cell1946 Neumann: Sealed Ni-Cd1960 Alkaline, Rechargeable Ni-Cd1970 Lithium, Sealed Lead Acid1990 Nickel metal hydride (NiMH)1991 Lithium ion1992 Rechargeable alkaline1999 Lithium ion polymer
Voltaic Pile
Types Of BatteryBasically batteries can be classifieds as two
types as primary batteries and secondary batteries.
Primary Battery(disposable) In primary batteries, the electrochemical reaction is
not reversible. Used when long periods of storage are required.During discharging the chemical compounds are
permanently changed and electrical energy is released until the original compounds are completely exhausted.
Lower discharge rate than secondary batteries.Thus the cells can be used only once.
Examples Of Primary Batteries
Zinc Carbon – Used in flashlights, toys
Heavy Duty Zinc Chloride – Used in radios, recorders
Alkaline – Used in all of the aboveLithium – Used in photoflashSilver Mercury Oxide – Used in
Hearing aid, watches, calculators
Zinc Carbon Battery This kind of batteries are generally used in
flashlights and toys
ChemistryZinc (-ve), Manganese Dioxide (+ve)Zinc Chloride and Ammonium Chloride paste as
electrolyteFeatures
+Inexpensive, widely available.– Inefficient at high current drain.– Poor discharge curve (sloping).– Poor performance at low temperatures.
Zinc Carbon Battery
Heavy Duty Zinc Chloride Batteries
This kind of batteries are generally used in radios and recorders.
Chemistry Zinc (-ve), manganese dioxide (+ve) Zinc chloride aqueous electrolyte
Features (compared to Zinc Carbon)+Better resistance to leakage.+Better at high current drain.+Better performance at low temperature.
Alkaline Batteries This kind of batteries are generally used in
toys, radios, recorders and flashlights.
Chemistry Zinc (-ve), manganese dioxide (+ve)Potassium hydroxide aqueous electrolyte
Features +50-100% more energy than carbon zinc+Low self-discharge (10 year shelf life)±Good for low current (< 400mA), long-life
use– Poor discharge curve
Alkaline Battery
Secondary Battery(Rechargeable)
In secondary batteries, the electrochemical reaction is reversible.
Used when short periods of storage are required.During discharging the chemical compounds
which are changed can be reconstituted by the application of an electrical potential between the electrodes.
Higher discharge rate than primary batteries.Thus such cells can be Rechargeable and used
many times.
Some Examples Of Secondary Batteries
Nickel Cadmium BatteryNickel Metal Hydride BatteryLead Acid BatteryLithium Ion Battery
Nickel Cadmium Batteries
ChemistryCadmium (-ve), nickel hydroxide (+ve)Potassium hydroxide aqueous electrolyte
Features+Rugged, long life, economical+Good high discharge rate (for power tools)– Relatively low energy density– Toxic
Cell Reaction Of Ni-Cd Battery
The half-reactions are:Cd+2OH- → Cd(OH)2+2e-
2NiO(OH)+Cd+2e- →2Ni(OH)2+2OH-
Overall reaction:2NiO(OH) + Cd+2H2O→2Ni(OH)2+Cd(OH)2
Advantages Of Ni-Cd Batteries
Available in different size and shapes.Have ability to deliver full power output
until end of cycleVery low internal resistanceSimple and fast to recharge Over 1000
cycles (if properly maintained)Operate in a range of temperatures.Tolerates abuse well and performs well
after long periods of storage.
Disadvantages Of Ni-Cd Batteries
It is three to five times more expensive than lead-acid
Self discharge up to 10% in a day. Its materials are toxic and the recycling
infrastructure for larger nickel-cadmium batteries is very limited.
Uses Of Ni-Cd BatteryNi-Cd batteries may be used individually or
assembled into battery packs containing two or more cells.
Specially Ni-Cd batteries are used in cordless and wireless telephones, emergency lighting and other applications.
With a low internal resistance, they can supply a high surge current. This makes them a favourable choice for remote controlled model airplanes, boats, cars and camera flash units.
Lead Acid BatteryChemistry
LeadSulfuric acid electrolyte
Features+Least expensive+Durable– Low energy density– Toxic
Cell Reaction Of Lead Acid Battery
Discharging(+) electrode: PbO2(s) + 4H+
(aq) + SO42-
(aq) + 2e- → PbSO4(s) + 2H2O(L)
(-) electrode: Pb(s) + SO42-
(aq) → PbSO4(s) + 2e-
Charging(+) electrode: PbSO4(s) + 2H2O(L) → PbO2(s) + 4H+
(aq) + SO42-
(aq) + 2e-
(+) electrode: PbSO4(s) + 2e- → Pb(s) + SO42-
(aq)
Advantages Of Lead Acid Batteries
Low maintenance requiredAvailable in all shapes and sizes.Best in terms of reliability & working
capabilities.Withstand slow, fast & overcharging.Capable to withstand long term inactivity
with or without solvent.Have the longest life cycle and a large
environmental advantage.97% of the lead is recycled and reused in
new batteries.
Disadvantages Of Lead Acid Batteries
Limited number of full discharges.Danger of overheating during charging.In some cases it may releases acid
fumes, which can cause numerous health issues in terms of long time exposure.
Corrosion may decrease battery life, so must be avoided through proper maintenance.
Lead Acid Battery UsesThe lead-acid cells in automobile
batteries are wet cells.Deliver short burst of high power, to
start the engine.Battery supplies power to the starter
and ignition system to start the engine.Supplies the extra power necessary
when the vehicle's electrical load exceeds the supply from the charging system.
Lithium Ion BatteryChemistry
Graphite (-ve), Lithium cobalt dioxide (+ve) Non aqueous electrolyte
Features+40% more capacity than Ni-Cd+Flat discharge (like Ni-Cd)+Self-discharge 50% lesser than Ni-Cd– Expensive
Charging Phenomena
AL CurrentCollector
Cu CurrentCollector
Electrolyte
LiCoO2Graphite
Lithium-Ion Battery Charging
AL CurrentCollector
Cu CurrentCollector
Electrolyte
LiMO2Graphite
Lithium-Ion Battery Discharging
Advantages Of Lithium Ion Battery
The most distinct advantage is high energy density.
Lower self discharge rate. (In comparison with Ni-Cd Battery)
No maintenance.No memory effect.No requirement for priming.Variety of types available.
Disadvantages Of Lithium Ion Battery
Require protection from overcharge & fully discharge.
Shows ageing.Transportation by air is sometimes
difficult.40% more costly than Ni-Cd batteries.No established system for recycling
large lithium-ion batteries.
Uses Of Lithium Ion Batteries
What If We Use Conducting Polymers In
BatteriesAdvantagesLonger cyclic timehigh discharge timeLess self discharge timeFlexible shapeEasy fabrication of component in film formDisadvantageCost
The Safety Issue
Referencewww.wikipedia.orgwww.doityourself.comwww.mcabatteries.comwww.Batteryuniversity.comwww.radioelectronics.comwww.duracell.com/OEMdata.energizer.comwww.rayovac.com/busoem/oemT. R. Crompton, Battery Reference Book,
Newnes, 2000D. Berndt, Maintenance-Free Batteries, Wiley,
1997C. Vincent & B. Scrosati, Modern Batteries,
Wiley, 1997