Rechargeable Batteries

By: Tolaz Hewa

Chemistry behind Batteries

O A battery is a package that consist of one or more galvanic cells used for the production and storage of electric energy. The power is generated because of the reaction that happens between the anode and the cathode in the galvanic cells.

O Each half cell contains an electrode and an electrolyte solution. The electrolyte solution usually has ions of the electrode in them.

O A Galvanic Cell is also known as voltaic cell which produces electrical energy spontaneously and

Chemistry behind BatteriesO Rechargeable batteries are

batteries that store electrical power. These batteries can be used multiple times and recharged.

O They are cheaper, more durable, and better for our environment than disposable batteries.

O Batteries have two half cells and the electricity current runs because of the difference in voltage between each electrode.

O The voltage runs through the electrolyte.

Chemistry behind Batteries

O Batteries are made up of plates with the help of reactive chemicals that are separated by barriers/seperators.

O These plates are polarized so that all the electrons are collected on one side of the plates.

O When a device is connected, a pathway is created to allow the flow of electricity from negative terminal to positive terminal.

O When current happens there is also electrochemical reaction that causes the electrons to replenish

Chart of Information on Battery Types

Chemistry Cell Voltage Energy Density (MJ/kg) Comments

NiCd 1.2 0.14

Inexpensive.High/low drain, moderate energy density.Can withstand very high discharge rates with virtually no loss of capacity.Moderate rate of self discharge.Reputed to suffer from memory effect (which is alleged to cause early failure).Environmental hazard due to Cadmium - use now virtually prohibited in Europe.

Lead Acid 2.2 0.14

Moderately expensive.Moderate energy density.Moderate rate of self discharge.Higher discharge rates result in considerable loss of capacity.Does not suffer from memory effect.Environmental hazard due to Lead.Common use - Automobile batteries

NiMH 1.2 0.36

Cheap.Not usable in higher drain devices.Traditional chemistry has high energy density, but also a high rate of self-discharge.Newer chemistry has low self-discharge rate, but also a ~25% lower energy density.Very heavy. Used in some cars.

Lithium ion 3.6 0.46

Very expensive.Very high energy density.Not usually available in "common" battery sizes (but see RCR-V3 for a counter-example).Very common in laptop computers, moderate to high-end digital cameras and camcorders, and cellphones.Very low rate of self discharge.Volatile: Chance of explosion if short circuited, allowed to overheat, or not manufactured with rigorous quality standards.

The advantages and disadvantages of using rechargeable batteries.

O CostO Besides the high initial cost of the battery, rechargeable

batteries can recharged up to 500 times which comes to be much more efficient than buying multiple non- rechargeable batteries.

O PerformanceO Even though at first rechargeable batteries had much

lower performance then standard alkaline batteries (non-rechargeable), the technology has grown very much to a point where major companies advertise that they perform better than standard batteries.

O ChargingO Charging rechargeable batteries can be a pain

sometimes. Especially if it forces the device to be off when charging. Some has very high discharging rate which means they need to be charged once more after not being used for a while.

The advantages and disadvantages of using rechargeable batteries.

O UsesO Some batteries depending their type, they

are only useful for some specific devices. Older devices may warn you not to you use Lithium-Ion which means it will not work well with them. Also because Lithium-Ion batteries are expensive, they are mainly used in computers, camera, and portable electronic devices.

O HazardsO Some of the rechargeable batteries have

chemicals in the that are more dangerous than alkaline batteries (especially Nickel-Cadmium). This makes them a very big threat to our environment. Some countries ban the usage of too many nickel-cadmium batteries.

More about batteriesBattery Type Total Capacity

Self-Discharge Rate

Use Characteristics

Nickel-Metal Hydride(NiMH)

Up to 1,000, AAA.Up to 2,700 mAh, AA.Available capacities vary widely. Check

the mAh rating before you buy.

Does not hold charge well over long

periods.Loses 4 percent

per day1, much more in warm

temperatures.

Works well in devices that require sudden

high amperage discharge, such as

digital cameras. Also works well in most

other devices.

Low Self DischargeNickel-Metal Hydride(LSD NiMH)

Up to 800, AAA.Up to 2,000, AAAlmost all LSD

batteries sold have close to these

capacities.

Holds charge well over long periods.Loses 15 percent per year2, very

slightly more in warm temperatures.

Works well in devices that require sudden

high amperage discharge, such as

digital cameras. Also works well in most

other devices.

Nickel-Cadmium(NiCd)

Up to 350 mAh, AAA.Up to 1,000 mAh, AA.Available capacities vary widely. Check

the mAh rating before you buy.

Loses 1 percent per day3, slightly

more in warm temperatures.

Does not work well in devices that require

sudden high amperage

discharges. Does not work well in digital cameras, but does work well in most

other devices.

What methods should be used for disposing batteries

O DISPOSING OF GENERAL PURPOSE & ALKALINE BATTERIESO Alkaline batteries can be safely disposed of with normal household

waste. But do not expose it to fire, there is a chance it will explode.O Companies like Duracell has stopped using mercury due to its danger

on the environment since 1993. Now they are made of other non-harmful metals such as steel, zinc, and manganese.

O Do not dispose too many of these batteries together at once. Because if the dead batteries have contact with each other there is a chance of reaction.

O RECYCLING BATTERIES WITH OTHER CHEMISTRIESO Because of the chemical inside rechargeable, lithium, lithium ion, and

zinc air batteries they should always be recycled. This included batteries for electronics such as cameras, music players, and other portable devices.

O Always look for the recycle symbol on your batteries.O Car batteries should be brought back to waste management centers

where they would be taken care of properly. Also there is a chance a auto worker would want your battery.

References:

O Christophe Derderian retrieved from http://www.des.pf/itereva/disciplines/sti/prod/apsecondes/FTP/TP%20HnD%20-%20Week%203/files/Docs/Rechargeable_battery_chemistries.pdf

O Ben, H. (2003, 23 05). uwaterloo. Retrieved from http://www.science.uwaterloo.ca/~cchieh/cact/c123/battery.html

O Moore, C. (2007). Advantages and disadvantages of rechargeable batteries. Retrieved from http://www.ehow.com/about_5397626_advantages-disadvantages-rechargeable-batteries.html

O Duracell. (n.d.). Retrieved from http://www.duracell.ca/en-CA/battery-care-disposal.jspx

O Calrecycle. (27 0). Retrieved from http://www.calrecycle.ca.gov/ReduceWaste/power/rechbattinfo.htm

Impacts of Rechargeable batteries in portable devices on

societyO It has allowed for many developments

in the portable electronics industry.O It has allowed us to make electronics

that will be live a longer age and will not need constant change of batteries.

O It has helped with the development of companies in the video game industries (Sony, Microsoft, Nintendo, Atari, etc.), portable MP3 player industries (Apple, Sony, SanDisk, etc.), and Cell phone industries (Apple, Samsung, Blackberry, etc.)

O It is been a great push towards the modern convenient life we live today with the electronics.

THE END