In any battery, an electrochemical reaction occurs. As a result of this reaction,
electrons move from one pole to the other. The voltage of the cell depends on the
actual metals and electrolytes used in the cell.
For example, in one cell of a car’s lead-acid battery:

The cell is made up of one plate of lead and another plate made of lead dioxide immersed in
a strong sulfuric acid electrolyte.

Lead reacts with SO4 (sulfate) to create PbSO4 (lead sulfate) releasing one electron.

Lead dioxide, hydrogen ions and SO4 ions, plus electrons from the lead plate, create PbSO4
and water on the lead dioxide plate.

As the battery discharges, both plates build up PbSO4 and water accumulates in the acid.
The voltage is about 2 volts per cell, so by combining six cells you get a 12-volt battery.
The principle behind a rechargeable battery is that when electrical energy is applied electrons flow
from positive to negative, opposite to that during discharge, and power is restored.
Alkaline:
Alkaline batteries are based on the conversion of MnO2 and Zn to Mn3O4 and ZnO. Until
recently, alkaline batteries were manufactured only to function as primary cells because it performed
more poorly with each recharge and recharging them was not safe. However, in their rechargeable
form, they allow for an efficient reverse reaction and are safe.
Lithium ion:
In lithium ion cells, the positive electrode is made of Lithium cobalt oxide, or LiCoO2, while the
negative electrode is made of carbon. When the battery charges, ions of lithium move through the
electrolyte from the positive electrode to the negative electrode and attach to the carbon and
during discharge, the lithium ions move back to the LiCoO2 from the carbon.
Nickel Cadmium:
In nickel-cadmium (NiCad) batteries, Cd(OH)2 and Ni(OH)2 are formed during cell discharge
and they readily convert back to their original electrodes, Cd and NiOOH, when the cell is recharged.
Nickel Metal Hydride:
The NiMH battery is made up of NiOOH as the positive electrode, metal H as the negative
electrode and KOH as the elctrolyte.
Zinc:
Zinc batteries consist of granulated powder mixed (zinc) that acts as an anode with an
electrolyte which has an addition of a gelling agent so contact is maintained between the
electrolyte and the zinc granules. The cathode allows contact of oxygen from air so that the reaction
is complete and electricity is produced.
Advantages and Disadvantages
Type of Rechargeable
Battery
Advantages
Disadvantages
Alkaline
 Loses charge gradually (allows
time to notice the need to
change the battery)
 More voltage (1.5V versus 1.2 V,
Alkaline to NiMH) [make light
brighter]
 Lower self-discharge rate=longer
periods of time of non-use
 No toxic metals
 Lower capacity (holds charge
for a shorter time)
 After each recharge, they lose
some of their charge capacity
 Can be recharged a fewer
amount of times
 Laptops, cell phones,
camcorders
 High power to rate ratio
 Not affected by ‘memory effect’
 Simple charging method
 Special batteries for such
devices as laptops, cellphones;
not the generic sizes (eg. AA, B)
 Require special recharger or
part of the device
 Prone to explode
 Specific storing requirements
 Changes in environment (ie
temperature) do not affect its
usage
 Resistant to some amount of
damage
 Long periods of storage do not
affect its usage
 High number of charge cycles
 Lower capacity than NiMH or
Alkaline
 Contain toxic metals
 ‘memory effect’: if battery is
recharged before it is drained,
the battery will recharge only
to that point; never full charge
 Have been replaced by NiMH
http://upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Rechargeable_alka
line_battery.jpg/220px-Rechargeable_alkaline_battery.jpg
Lithium-ion
http://dev.emcelettronica.com/common-rechargeable-battery-types
Nickel-Cadmium
http://dev.emcelettronica.com/common-rechargeable-battery-types
Nickel-Metal Hydride
 Light weight
 Higher capacity (than NiCad)
 No toxic metals
 Used in electric vehicles
 Less chance of ‘memory effect’

 Different capacity choices
 High capacity may not
completely charge
 Less voltage than Alkaline
 Periods of non-use: 2-3 months
 Self-discharge < 25%/month
 Changes in environment (ie
temperature) do not affect its
usage
 Long periods of storage do not
affect its usage
 Expensive
 Life cycle is average
http://dev.emcelettronica.com/common-rechargeable-battery-types
Nickel-Zinc
http://www.cleverandeasy.com/images/stories/powergenix_rechargeable_batteri
es.jpg
Capacities
There are different kinds of rechargeable batteries, and each kind and brand has a different
capacity. The life of a rechargeable battery before needing to recharge can range between a few
days, to a few months, depending on the type and the conditions of its usage.
A batteries life expectancy is usually rated based on when the battery becomes unusable. This
is typically when the batteries life expectancy becomes less than 80% of what it used to be. However
on average the amount of cycles this would take would be roughly between 1500-2000 cycles.
Alkaline
NiCd
NiMH
USBCell
Eneloop
Li-ion
NiZn
Main Brand
Many
Many
Many
USBCell
Sanyo
Li-ion
PowerGenix
Technology
Alkaline
NiCd
NiMH
NiMH
NiMH
Li-ion
NiZn
Power Rating
(AA type, mAh
typical)
2500
2300
2300
1300
2000
N/A
1500
Voltage
1.5
1.2
1.2
1.2
1.2
3.6
1.6
Current
Low
High
High
High
High
High
High
http://www.cleverandeasy.com/Multimedia/rechargeable-battery-comparison-table.html
Social Impact
The rechargeable battery has revolutionized society as we know it
today; this technology makes things we take for granted such as laptops,
mp3s and cell phones, a reality. Lithium ion batteries, most commonly
used in many portable devices today, make them practical to use
because they are cheap, they don’t continually require replacement, as
they could be recharged.
Lithium ion, Nickel-Metal Hydride (NiMH) and alkaline
batteries are used in many consumer electronics such as hand
blenders, electric drills and hair trimmers, and many other
technologies which require a constant supply of electricity.
Previously, these appliances and many others required wired
electrical connections which not only made their usage sometimes
very inconvenient but also dangerous. For example, on
construction site, large wires to provide electricity for drills could
prove to be a tripping hazard. Today, with rechargeable batteries,
these appliances and tools are becoming cordless, making them
more convenient and safe to use.
As a society, as we struggle deal with depleting energy resources such as petroleum,
rechargeable battery technology will play a critical role in providing solutions to these problems.
Advances in this technology will make these rechargeable batteries efficient and powerful enough
to commercially power our cars and even homes.
Disposal
Improperly disposed of batteries are causing many problems: social, environmental and health.
Batteries typically contain harmful chemicals such as mercury, nickel, cadmium, etc. When these
batteries are improperly disposed of, (i.e., thrown in the garbage), they may end up in landfills and
cause hazards:



They may reach lakes or seep through the soil into groundwater,
poisoning the water
May harm wildlife near these landfills
Cause air pollution as some of these metals may be released into
the air when burned.
Due to these and many other negative effects of improper disposal
of these batteries, it is very important to dispose of them safely.
Batteries Disposal Chart
Battery Type
Sizes Available
Examples of Use
Classification
Alkaline
AAA, AA, C, D, 6V,
9V
Flashlights, toys, clocks, remote controls,
etc
Non-Hazardous
Wastes
Lithium
3V, 6V, 3V, button
Cameras, calculators, computers
Non-Hazardous
Waste
Nickel-Cadmium
(NiCad)
Nickel-Metal
Hydride (NiMH)
AAA, AA, C, D, 6V,
9V
AAA, AA, C, D, 6V,
9V
Flashlights, toys, cell phones, power tools,
computers
Flashlights, toys, cell phones, power tools,
computers
Hazardous
Waste
Non-Hazardous
Waste
Alkaline
Manganese
AAA, AA, C, D
Flashlights, toys, clocks, radios
Non-Hazardous
Waste
Sealed Lead
Acid
Lead Acid
Vehicle Batteries
Multiples of 2 Volts:
2V, 6V
12V, 6V
Cameras, power tools, wheelchairs,
cameras
Cars, motorcycles
Hazardous
Waste
Hazardous
Waste
Non – Hazardous Waste: These batteries are legally classified as non-hazardous waste and can legally
be disposed of in the garbage. This is only the case because due to legislations passed in the 1990’s,
mercury is banned from these batteries but the chemicals in these batteries are still semi-toxic (nickel)
and there is the possibility of a fire if some of these chemicals are exposed to water during the
corrosion process (lithium).
As a general rule, rechargeable batteries should be recycled as they all contain recyclable
materials. Batteries classified as both hazardous and non-hazardous can be disposed of at battery
recycling centers, which can be found using the “Dropoff Locator” found at
http://www.call2recycle.ca/drop-off-your-old-batteries.php?c=149&d=486&w=9913.
Batteries classified as hazardous waste can also be disposed of at a Household Hazardous
Waste Collection Sites Located at City of Toronto Solid Waste Drop-off Depots which can be located
using the website http://www.toronto.ca/garbage/depots.htm.
Spent vehicle batteries can be taken back to the
place where they were purchased; slight discounts are also
sometimes offered with the purchase of a new battery when
a spent battery is returned.
Battery Recycling Drop-Off Locations
http://www.call2recycle.ca/drop-off-your-old-batteries.php?c=149&d=486&w=9913
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