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| Primary
batteries are
used once, and then can’t be recharged to replenish chemical
energy. The common Carbon-Zinc battery, Alkaline battery and Mercury
battery are primary batteries. There are various applications (refer to comparison
table). However,
because of single use and the toxic mercury as a component, it causes a
huge burden on the environment and our body (pollution). |
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| Carbon-Zinc
Batteries
(Dry Batteries) |
 The
anode is made of zinc, and the cathode is made of carbon rod. Its
electrolyte is Ammonium chloride or Zinc chloride. The operation
voltage is about 1.5V. The main use is for small current production
because hydrogen can accumulate on carbon rod to reduce energy
efficiency and durability. The larger working current, the lower
electricity capacity. If the storage temperature is over 39℃, it
reduces working life by 50%. That’s why the dry batteries
must be
kept in a cool place. The normal durability of dry batteries is about 3
years. |
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| Alkaline
Batteries |
 Alkaline
batteries mainly improve the shortage of carbon-zinc batteries. The
anode is made of zinc and the cathode is made of manganese dioxide. Its
electrolyte is high concentration Potassium-hydroxide. Its working life
is about 10 times of carbon-zinc batteries’ at high c-rate
condition and the voltage can be maintained at 1.5V after long-time
working. The normal durability of alkaline batteries is about 5 years. |
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|
Mercury
Batteries
|
 The
anode is made of zinc-mercury alloy, and the cathode is made of
mercuric oxide. The electrolyte is potassium hydroxide. The typical
products are coin batteries and cylindrical batteries. The operation
voltage is 1.35V (for industry equipments) or 1.4V (for general use).
Because the voltage keeps constant with various ampere output, it keeps
good performance under shock or high-speed conditions. That’s
why
cameras and many communication devices are adapted for mercury
batteries. The difference between mercury batteries and carbon-zinc and
alkaline batteries is; the former seldom has a leakage problem, and the
time of storage is more than 10 years. |
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| Comparison
of Primary
Batteries |
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| Operation Voltage |
1.5V |
1.5V |
1.35
or 1.4V |
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| Working Life |
3 yrs |
5 yrs |
>10 yrs |
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| Purpose |
Apply to low energy,
low c-rate and short-time working required application |
Apply
to high c-rate and long-lasting required application. Operation voltage
is more stable than dry batteries’, and the capacity is
higher as
well. |
Stable operation
voltage. It keeps good performance under shock or high-speed condition. |
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Pollution
|
Mercury
causes the most
serious pollution in all components of primary batteries. Among all of
them, mercury batteries contain the highest level of mercury. Even in
the so-called eco-friendly carbon-zinc or alkaline batteries, there is
still a bit of mercury required in the production process.
Without proper recycling and through landfill or incineration, mercury
will be exposed to the environment. When people eat the polluted
seafood or drinking polluted ground water, mercury is stored in the
body and causes nervous system, kidney and liver damage. During the
17th century, animal skins were rinsed in an orange solution of mercury
in the making of felt hats. After the hatters were poisoned, they acted
strangely. People thought those hatters were mad or cursed by factory
which inspired the phrase “mad as a hatter”. Today,
we know
it was caused by mercury poisoning. |
| How
serious a pollution
problem can mercury batteries cause? According to the research, an
improperly recycled coin battery can pollute 6million tons water, the
amount equals a person’s lifetime requirement. |
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