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The Lithium ion battery is the preferred source of power for many wireless and portable
consumer products. A typical battery pack with lithium ion cells features a variety of active and
passive safety devices and protection circuitry to prevent or mitigate potential cell failures. One
of the passive safety components in a lithium ion cell is the cell-can's mechanical safety vent,
which is intended to release the internal pressure of the cell when a specified pressure is reached,
but prismatic cells swell and cylindrical cells bulge during pressurization. It is therefore,
desirable to test the cell's venting mechanism in a controlled manner in order to ensure that both
the cell's can and the performance of the safety vent is not compromised and that the results are
not skewed by the
test method. A
suitable test setup
should not inhibit
the natural
expansion of the
cell's can during
the test. This
paper discusses
the various
venting
mechanisms
employed by
prismatic and
cylindrical
lithium ion cells
and test methods
to characterize the mechanical safety vent's opening pressure for both cylindrical and prismatic
cells
Slide-In Battery Contacts
Economical contacts are designed to "slide-in" to the battery compartment of electronic equipment. Coil spring
contacts are designed with a unique spring tension ability and they accurately adjust to variations in battery length.
Snap-In Battery Contacts
Economical and reliable battery contacts, consisting of leaf spring, coil spring and button type designs, is ideal for use
with electronic products having molded-in battery compartments.
Thru-Hole Battery Contacts
Button and Spring contacts are ideal for top-side board mounting in PCB packaging applications
Surface Mount Battery Contacts
Button and Spring contacts are ideal for top-side board mounting in PCB packaging applications. Supplied in Bulk or
on tape and reel
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About Batteries
o
How Do Batteries Work?
o
Battery History
o
Battery Care
o
Battery Leakage
o
FAQ
Ever wonder how that little battery powers your favorite devices? We give you an inside look at
how alkaline batteries work.
You can think of a battery as a small power plant that converts a chemical reaction into electrical
energy. Various dry cell (or alkaline) batteries can differ in several ways, but they all have the
same basic components.
Battery Parts

Container
A steel can housing the cell’s ingredients to form the
cathode, a part of the electrochemical reaction.

Cathode
Manganese dioxide mixture and carbon. Cathodes are the
electrodes reduced by the electrochemical reaction.

Separator
A non-woven, fibrous fabric that separates the electrodes.

Anode
Powered zinc metal. Anodes are the electrodes that are
oxidized.

Electrodes
Where the electrochemical reaction takes place.

Electrolyte
A potassium hydroxide solution in water. The electrolyte
is the medium for the movement of ions within the cell and carries the iconic current inside the
battery.

Collector
A brass pin in the middle of the cell that conducts
electricity to the outside circuit.
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1
2
3
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6
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Constructing The Battery

Container
It all starts with an empty steel can – the battery
container.

Cathode Mix
A cathode mix – finely ground powders of manganese
dioxide and conductors carrying a naturally-occurring electrical charge – is molded to the
inside wall of the empty container.

Separator
A separator paper is inserted to keep the cathode from touching the anode.

Separator
A separator paper is inserted to keep the cathode from
touching the anode.

Anode
The anode, which carries a negative electrical charge, and
potassium hydroxide electrolyte are then pumped into each container.

Collector
The brass pin, which forms the negative current
collector, is inserted into the battery which, is then sealed and capped.
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1
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6
Powering The Device
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Chemical Reacts
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In This Section
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Battery Anodes
Battery Cathodes
Depletion Aggregation
Membranes
BATTERY ANODES
Introduction
The anode is the negative electrode of a primary cell and is always associated with the oxidation or the release of
electrons into the external circuit. In a rechargeable cell, the anode is the negative pole during discharge and the
positive pole during charge.
Lithium
Anode
The anode in the battery deserves an equal say in the overall performance of a battery. For an effective development
of a high energy density battery, the use of high capacity electrode materials (anode& cathode) is an essential
factor. For such systems, alkali metals are perhaps the obvious choice. The most promising types of advanced
batteries currently under production are based on lithium anodes. The choice of the anode material is very much
restricted by the need for a high energy content, which is unavoidably linked, to the use of an alkali metal as the
main anode material.Lithium is generally preferred, since it can be more easily handled (though with care) than other
alkali metals and more significantly, the lightest and the most electropositive among the alkali metal family. Also, the
low density of lithium metal (0.534g/cc) leads to the highest specific capacity value of 3.86Ah/g, which stands
exceptional. Therefore, lithium batteries possess the highest voltage and energy density of all other rechargeable
batteries and are therefore favored in applications related to portable appliances where low weight and small volume
are the major constraints. The advantages of using lithium metal as the anode are as follows:
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Good reducing agent
Highly electropositive(so higher voltage is obtained depending upon the cathode used)
High electrochemical equivalence High capacity (3.82Ah/g) and energy density (1470Wh/Kg)
Good conducting agent
Good mechanical stability
Ease of fabrication/compact design
The essential reaction of metallic lithium anode is very simple:
But, in spite of this simplicity, the practical application of Li metal to a rechargeable anode has been very difficult due
to some crucial issue. The most important one is that Li metal usually will tend to deposit as a dendrite or mossy
structure during charge, and the disordered metallic deposit gives rise to a poor coulombic efficiency. This happens
because such a fine Li metal often acts as an active site inducing reductive decomposition of electrolyte components.
Part of the deposit may become electrically isolated and shedding may also occur. Furthermore, the fine metallic
lithium may easily penetrate into the separator and eventually cause internal short, this resulting in heat generation
and contingent ignition. One of the main reasons for the failure of rechargeable lithium systems lies in the reactivity
of lithium with electrolytes]. Hence the hazardous nature of Li has paved way to identify some other safer anode
materials, possessing comparably the same electrochemical features as that of lithium.
Alternate
anodes
for
lithium
batteries
Carbonaceous materials, which allow the intercalation of Li within the layers, are clearly the most suitable candidates,
leading to the popularly known lithium-ion or shuttlecock or Lithium Rocking Chair Batteries (RCB). Most carbon
varieties including graphite are gaining importance as attractive candidates of anode materials for rechargeable
lithium batteries, because they can accommodate lithium reversibly and offer high capacity, good electronic
conductivity and low electrochemical potential (with respect to Li metal). The maximum amount of lithium that can
be intercalated within the graphite structure is 1 per 6 carbon atoms, yielding a specific capacity of 372mAh/g. The
cost, availability, performance and potential (vs. Li metal) of carbon-based materials are all acceptable and even
preferable when compared to lithium metal anode for practical cells. An important evidence for this is the
commercial availability of LiCoO2/carbon cells manufactured by Sony Inc. There is no significant swelling of, or stack
pressure generation by the carbon electrode on prolonged cycling and therefore Li-ion cells can be constructed as flat
or prismatic cells with thin-walled cases or in any other cell configurations. The shortcomings on the deployment of
different types of anode materials are displayed in Table 1
MATERIAL
REMARK
LITHIUM
DENDRITE GROWTH, EXPENSIVE, TOXIC
CARBON
IRREVERSIBLE CAPACITY LOSS
TIN
INCLUSION OF SOLID ELECTROLYTE PHASE IN THE ELECTRODE
ATCO
COMPLICATED LITHIUM UPTAKE/REMOVEL
M-M ALLOY
LARGER VOLUME CHANGES (MECHANICAL DECRIPITATION)
TERNARY METAL VANADATES
ARGUABLE Li DIFFUSION MECHANISM
METALLOIDS
MOISTURE SENSITIVE
Hollow Fe3O4 Nano materials as anodes
Figure 1.
The current work investigates the potential for hollow nanostructures to mitigate the pulverization problem and fast
capacity fading for anode materials in lithium-ion batteries (LIBs). Hollow Fe3O4 nanoparticles are synthesized via a
template-free solvothermal method using FeCl3, urea and ethylene glycol as starting materials. Temporal XRD and
TEM (Figure 1) studies indicate that the growth follows an inside-out Ostwald ripening mechanism. Higher
concentrations of urea in the starting material result in lower percentages of hollow particles (phi) and this
observation is consistent with the proposed growth mechanism. The performance of the hollow particles as anode
materials in LIBs is tested and shown to be superior to their solid counterparts,
Figure 2.
with higher percentages of hollow particles giving better performance (Figure 2), which provides evidence for the
hypothesis that hollow structures are able to alleviate the pulverization problem. Cyclic voltammograms of Fe 3O4
nanoparticles are analyzed which provides some insight into the reaction mechanism of the lithium-ion
insertion/deinsertion process.
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