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