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Unit 14- Assignment 4- P4
A cell is a device that is used to store electrical energy
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Primary cell - A cell in which an irreversible chemical reaction generates electricity; a cell that cannot
be recharges
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Secondary cell - A rechargeable electric cell that converts chemical energy into electrical energy by a
reversible chemical reaction
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Primary cells
These are not rechargeable
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Higher life-cycle cost (£/kWh)
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Disposable
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Higher initial cost
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Regular maintenance required
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Cell type
Simple cell

Leclanche dry cell

Lead acid cell

Zinc-air fuel cell

Description
Simple cell batteries work
similar to any other battery
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A leclanche cell is a dry battery
that uses a moist paste as the
electrolyte solution
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A typical car battery consists of
eight cells each with a nominal
p
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of 1
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A primary battery with very
high energy density that uses
atmospheric oxygen as the

Uses

Clocks
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Remote controls
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Boats
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Watches
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Film
cameras
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A semiconductor device that
convers the energy of sunlight
into electrical energy
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Satellites
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Telescopes
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They produce electricity through a series of
reactions between a anode (which is negatively charged), a cathode (which is positively charged) and
an electrolyte
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The chemical reactions between
the electrolyte and the anode/cathode cause a build up of electrons at the anode and a lack of
electrons at the cathode
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The reactions change the chemicals in the anode and cathode; this will eventually cause
them to stop supplying electrons
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Lead acid batteries
Lead acid batteries are a secondary type of battery
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The
cells are filled with an electrolyte made up of sulphuric acid
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As this occurs, the hydrogen within the acid reacts with the lead dioxide to form water
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As this
occurs, lead oxide builds up on both plates which blocks the reaction
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Leclanche dry cell
Dry cells, normally refer to a primary cell
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The anode is made up of zinc and the cathode is made up of
carbon and manganese dioxide
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Electrons are built up in the zinc metal sleeve and are given off in the carbon
electrode
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These batteries have high energy densities and are relatively inexpensive to make
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Solar cells
Solar cells are not useful for storing energy, it is not a primary or secondary
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When light in incident on electrons near the boundary between the N-type and
P-type silicon, it gives the electrons energy through the photoelectric effect
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Unit 14- Assignment 4- M4
Primary cells
386/301 Energizer watch battery - Zinc-air fuel cell
Chemical System:
Designation ANSI/NEDA

Silver Oxide (Zn/Ag2O)
1133SO/1132SO

Designation IEC
Nominal Voltage
Typical Capacity
Capacity Test
Typical Weight
Typical Volume
Impedance (40 Hz)

SR43
1
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2 volts)
6
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7 grams (0
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)
0
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27 in3)
5 to 15 ohms

This graph shows that as you increase the time you use the battery for, the voltage decreases
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55V to 1V
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Advantages:
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The watch battery has a high energy density
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This means that that there is a
lot of energy stored in 0
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This means that the
battery would last long and would not have to be changed frequently, it would last longer
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This means that the voltage and
current would not rapidly decrease if left on unused for a while
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Watch
batteries are a problem as a great deal of metal is used for their comparatively small size and
they can contain mercury, silver, cadmium, lithium, or other heavy metals as their main
component
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These batteries are also non-toxic
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As they last long, not much money would have to be
spent to power your watch
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Disadvantages:
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There is a certain amount of power that watch batteries can supply
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This means that they would have to
be replaces when the power has ran out
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During use, and especially on overcharge, the water in the electrolyte splits into hydrogen
and oxygen
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In flooded batteries,
water can be added but in sealed batteries, water loss leads to an eventual dry-out and
decline in capacity
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Disposal hazards:
Batteries may produce the following potential problems or hazards:
•
•
•
•
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Pollute the lakes and streams as the metals vaporize into the air when burned
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Expose the environment and water to lead and acid
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May cause burns or danger to eyes and skin
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Dry cell batteries contribute about 88 percent of the total mercury and 50 percent of the cadmium in
the municipal solid waste stream
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When burned, some heavy metals such as mercury may vaporize and escape into the air,
and cadmium and lead may end up in the ash
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Energizer industrial - Alkaline
Capacity - 1
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After
around 9 hours discharges, the voltage begins to fall rapidly, from ~1V to 0
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When the current is
drained, the voltage decreases
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These batteries are very cost effective
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This battery is suitable for a wide range of consumer applications, such as clocks, toys and
remote controls
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Disadvantages:
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These batteries have the propensity to leak a white substance called potassium hydroxide
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Potassium hydroxide can result in chemical burns
and other health-related symptoms if exposed to the skin, mouth or eyes
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Disposal hazards:
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Chemical Burns

Potassium hydroxide can cause mild to severe chemical burns if exposed to bare skin
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Any
skin exposed to potassium hydroxide should be flushed with water immediately
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Poisoning

Potassium hydroxide from a leaking battery may cause poisoning if it is ingested or inhaled
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If ingested, call a physician immediately and follow her instructions
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The industrial applications that they are normally used in are clocks, toys, torches and remote
controls
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9A to 10
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8A to 10
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1Ah
5 hour rate ( 3
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20V ) - 15
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60V ) - 8
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60V ) - 6
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After
it discharges, the voltage begins to fall rapidly, from ~12V to 8V
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During discharge, the lead dioxide (positive plate) and lead (negative
plate) react with the electrolyte of sulphuric acid to create lead sulphate, water and energy
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During charging, the cycle is reversed: the lead sulfate and water are electro-chemically converted to
lead, lead oxide and sulfuric acid by an external electrical charging source
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As they last long, not much money would have
to be spent to power the device
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It is robust and tolerant to abuse and
overcharging, so you would rarely need to purchase a new one
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•

It can be left on charge for long periods of time and it would not damage the battery
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They are also
distributed around the world, which makes them available to anyone
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Disadvantages:
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These batteries are very heavy and bulky, which means that they are not very portable
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This then leads to the dangers of overheating during
charging
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Gassing is the production and release of bubbles of hydrogen and oxygen due to the
breakdown of water in the electrolyte during the charging process, particularly due to
excessive charging, causing loss of electrolyte
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Sulphation may occur if a battery is stored for prolonged periods in a completely discharged
state or very low state of charge, or if it is never fully charged, or if electrolyte has become
abnormally low due to excessive water loss from overcharging and/or evaporation
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In extreme cases the large crystals may cause distortion
and shorting of the plates
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Completely discharging the battery may cause damage beyond repair
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The result is chunks of lead on the bottom of the cell and holes in the
plates which cannot be repaired
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These particular batteries contain lead, a highly toxic metal and sulphuric acid, a corrosive
electrolyte solution
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Standby/Back-up/Emergency power for electrical installations
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iPhone 6 battery - Li-ion polymer battery
Capacity - 3
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91Whr
1810mAh

This graph shows that as you increase the time you use the battery for, the voltage decreases
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25V to -3
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When the
current is drained, the voltage decreases
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It is potential for higher capacities
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This is good for when in emergencies as it would last longer than other batteries
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So this battery is multi-purpose
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This means
the battery last loner than other batteries
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Disadvantages:
•
•

This battery requires protection to maintain voltage and current within safe limits
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These batteries are expensive to manufacture; it is around 40% higher in cost than a nickelcadmium battery
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This graph shows that as you increase the time you use the battery for, the voltage decreases
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2-0
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However, the lithium
battery discharges at a much slower rate, falling rapidly at around 13-14 hours at ~1
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The alkaline
battery discharges at a normal rate falling very rapidly at around 10 hours at ~1V
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5W
P = IV
I = P/V
V = 2 * D size batteries = 3V
Current drain: I = P/V = 0
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16A
If a typical DAB radio drains ~0
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16 = 62
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16 = 93
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7V
Current drain: 450mA
[source: http://www
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com/itm/2200LM-CREE-XM-L-T6-LED-Flashlight-Focus-Torch-light-LampZoom-18650-Charger-/321592843938?pt=LH_DefaultDomain_2&hash=item4ae06d5ea2]
If a typical torch drains 450mA
How long will it last with primary and secondary cells?

Secondary - 6Ah
Primary - 2
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45 = 13
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6/0
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78 Hours
[Primary alkaline battery source: http://en
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org/wiki/List_of_battery_sizes]

A mobile phone - 1900mAh External Pack Backup Battery Charger Protect Case for iPhone 4 4S

Current drain - 500mA = 0
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9Ah
Voltage - 5V
Reference: http://www
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co
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5 * 5 = 2
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5A

Capacity of a primary cell battery:
Primary - 4 * 2
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4Ah
Suppose I attach four AA size alkaline batteries to an iPhone 4s
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wikipedia
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4 * 0
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2 Hours

Capacity of a secondary cell battery:
Capacity = Current * time
Time = Capacity / Current
1
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5 = 0
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The primary battery (which lasts for 93
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5 hours)
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You do not need to be near a socket to use it
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However, for the torch, the secondary battery (which lasts for 13
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The secondary battery last much more longer than the primary batteries
(which only last 5
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Also the secondary battery can be recharged over and over again
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Also,
you would not need to keep buying primary batteries every time they go flat, as long as you charge
the batteries within a reasonable amount of time, they should last very long
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The primary battery lasts much more longer (5
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95 hours)
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But the primary
battery is a long lasting battery; it is useful when in an emergency, as the phone would stay powered
for a longer amount of time
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