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Battery Glossary
A B C D E F G H I J
K L M N O P Q R S T U V W X Y Z
A ………………………………………………………………………………………………………………………….
Alkaline: A primary battery (non-rechargeable) often used in electronics applications
requiring heavy currents for long periods of time (i.e.: CD players, radios,
etc.). Alkaline batteries can deliver 50-100% more total energy than
conventional Carbon/Zinc batteries of the same size, hence their popularity in
consumer applications.
Ampere-Hour: It is an
unit to measure battery capacity of at different current for different
durations.
Ampere-Hour Capacity: It measures the electricity stored in a battery.
Anode: The electrode in an electrochemical cell where oxidation takes place. During
discharge, the negative electrode of the cell is the anode. During charge, the
positive electrode is the anode. In a primary or secondary cell, the metal
electrode that gives up electrons to the load circuit and dissolves into the
electrolyte.
Available Battery Capacity: The
available capacity from a battery at working conditions. It depends on several
factors such as usage history, discharge rate, using condition, and end-point
voltage.
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Battery: A energy storage device that
can turn chemical energy into electrical energy.
Battery Capacity: The total electric output of a battery can deliver. It is usually expressed in
ampere-hours or watt-hours. You can convert the ampere-hours capacity into
watt-hours by multiplying the former by battery voltage.
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C …………………………………………………………………………………………………………………………..
C-Rate (also see Hourly Rate):
Discharge or charge current, in amperes, expressed in multiples of the rated
capacity. For example, C/10 discharge current for a battery rated at 1.5 Ah is:
1.5 AH/I 0 = 150 mA (A cell's capacity is not the same at all discharge rates
and usually increases with decreasing rate.)
Capacity: The total
number of ampere-hours or watt-hours that can be withdrawn from a fully charged
cell or battery under specified conditions of discharge.
Capacity Offset:
A correction factor applied to the rating of a battery if discharged under
different C-rates from the one rated.
Capacity Retention (or Charge Retention):
The fraction of the fall capacity available from a battery under specified
conditions of discharge after it has been stored for a period of time
Carbon/Zinc:
A primary battery (non-rechargeable) commonly used in low drain consumer
applications (i.e.: clocks, calculators, garage door openers, etc.). Available
in the same sizes as the Alkaline and Manganese Dioxide (“AA”, “AAA”, 9 volt,
“C”, “D”) the Carbon/Zinc is one of the most widely used dry primary batteries
because of its low cost and reliable performance.
Charge: The process of converting electrical energy into chemical energy.
Charge Rate: The charging current applied to a rechargeable battery. Expressed as a multiple of the rated capacity of the
Battery. For example,
a C5 charge rate of a 50 Ah cell is expressed as, C5 rate = 50 Ah / 5 h
= 10 A.
Cathode:
The electrode in an electrochemical cell where reduction takes place. During
discharge, the positive electrode of the cell is the cathode. During charge in a
rechargeable battery, the negative electrode is the cathode.
Cell:
The basic electrochemical unit used to generate or store electrical energy.
Cell Mismatch:
Cells within a battery pack that contain different capacity and voltage levels.
Cell Reversal:
The stronger cells of a battery (several cells connected in series) impose a
voltage of reverse polarity across a weaker cell during a deep discharge.
Charger: A device capable of supplying electrical energy to a battery.
Charge Control:
Technique for effectively terminating the charging of a rechargeable battery.
Conditioning:
A process that utilizes a series of heavy discharges and recharges on a battery
to assure optimum performance.
Constant Current:
A battery discharge regime whereby the current drawn during the discharge
remains constant.
Constant Power: A battery discharge regime whereby the current during the discharge increases as
the battery voltage decreases.
Constant Resistance: A battery discharge regime whereby the resistance of the equipment load remains
constant throughout discharge.
Continuous Test: A test in which a battery is discharged to a prescribed end point voltage
without interruption.
Coulomb:
The amount of electricity transported by a current of one ampere flowing for one
second.
Current Collector:
An inert structure of high electrical conductivity used to conduct current from
or to an electrode during discharge or charge.
Current Density:
The current per unit active area of the surface of an electrode.
Current Drain:
The current withdrawn from a battery during discharge.
Current Limiting Chargers:
A charger that keeps the charge current constant during the charge process but
allows the voltage to Fluctuate (typically used on NiCd and NiMH chargers).
Cutoff Voltage: The
battery voltage at which the discharge is terminated. The cutoff voltage is
specified by the battery manufacturer and is generally a function of discharge
rate.
Cycle:
A sequence where a charged battery is discharged and recharged.
Cycle Life: The number of cycles under specified conditions that are available from a
secondary battery before it fails to meet specified criteria as to performance.
Cylindrical Cell:
The positive and negative plates are rolled up and placed into a cylindrical
container (as opposed to stacking the plates in a prismatic cell design).
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D …………………………………………………………………………………………………………………………..
Deep Discharge: Withdrawal of all electrical energy to the end-point voltage before the cell or
battery is recharged.
Depth of Discharge:
The ratio of the quantity of electricity (usually in ampere-hours) removed from
a battery to its rated capacity.
Direct Current:
Electrical current that flows in one direction only. Batteries produce direct
current as the current flows from a negative to a positive source.
Discharge:
The conversion of the chemical energy of a battery into electrical energy, and
the withdrawal of the electrical energy into a load.
Discharge Rate:
The rate, usually expressed in amperes, at which electrical current is taken
from the battery.
Drain:
The current withdrawn from a battery during discharge.
Dry Cell:
A cell with immobilized electrolyte.
Dumb Battery:
Straight battery pack without internal circuits enabling communication between
the battery and the user.
Duty Cycle:
The operating regime of a battery including factors such as charge and discharge
rates, depth of discharge, cycle duration, and length of time in the standby
mode.
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E …………………………………………………………………………………………………………………………..
E-Rate:
Discharge or charge power, in watts, expressed as a multiple of the rated
capacity of a cell or battery that is expressed in watt-hours. For example, the
E/10 rate for a cell or battery rated at 17.3 watt-hours is 1.73 watts. (This is
similar to the method for calculating C-Rate.)
Electric Current:
The movement of electrons along a conductor.
Electrochemical Equivalent:
Weight of a substance that is deposited at an electrode when the quantity of
electricity which is passed is one coulomb
Electrolyte:
The medium which provides the ion transport mechanism between the positive and
negative electrodes of a cell.
End-point Voltage:
The prescribed voltage at which the discharge (or charge, if end-of-charge
voltage) of a battery may be considered complete.
End Voltage Cutoff:
same as End Point Voltage.
Energy Density:
The ratio of the energy available from a battery to its volume (Wh/L) or weight
(Wh/kg).
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F …………………………………………………………………………………………………………………………..
Fast Charge:
Typical fast charge time for a NiCd is 1 to 3 hours. The fast-charger detects
the state of charge and switches to trickle charge when full-charge is reached.
Final
Battery Voltage: Same as Cutoff voltage,
it the bottom limit voltage when the battery is completely discharged. It
depends on battery types, discharge rate and other use conditions.
Float:
The use of batteries in which they are charged by an application to be ready for
use if the primary power to the application fails. Also called standby or
backup.
Float Charge:
Similar to trickle charge. Compensates for the self-discharge on a SLA
battery
Forced Discharge:
Discharging a cell in a battery, by the other cells or an external power source,
below zero volts into voltage reversal.
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G …………………………………………………………………………………………………………………………..
Gravimetric Energy:
The ratio of the energy output of a cell or battery to its weight (Wh/kg). This
term is used interchangeably with specific energy.
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H …………………………………………………………………………………………………………………………..
High-rate Discharge: Withdrawal of large currents for short intervals of time, usually at a rate that
would completely discharge a cell or battery in less than one hour.
Hourly Rate:
A discharge rate, in amperes, of a battery which will deliver the specified
hours of service to a given cutoff voltage.
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I …………………………………………………………………………………………………………………………..
Impedance Intermittent Test:
Used in terms of the battery's internal resistance a test during which a battery
is subjected to alternate periods of discharge and rest according to a specified
discharge regime.
Internal Impedance:
The opposition exhibited by a circuit element (cell or battery) to the flow of
an alternating current (a/c.) of a particular frequency as a result of
resistance, induction and capacitance.
Internal Resistance (IR):
The opposition exhibited by a circuit element to the flow of direct current
(D.C.). In a cell, the internal resistance is the sum of the ionic and
electronic resistances of the cell components.
IR Drop:
A voltage drop associated with the electrical resistance (R) of a battery or
current flow (I). The voltage drop is the product of the current (in amperes)
and the resistance (in ohms).
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L …………………………………………………………………………………………………………………………..
Limiting Current:
The maximum current drain under which the particular battery will perform
adequately under a continuous drain. The rate is based on whatever drain rate
reduces the running voltage to 1.1 volts.
Lithium Ion (Li Ion):
One of the newer rechargeable battery technologies, Li Ion batteries can deliver
40% more capacity than comparably sized NiCd batteries and are one of the
lightest rechargeable batteries available today. Li Ion batteries are the
batteries of choice in notebook computers, wireless telephones and many
camcorder models. They are also one of the more expensive rechargeable
technologies.
Lead Acid:
Still the most popular battery used today its main application is for the
automobile industry, although it has a growing number of other applications. Its
advantages are low cost, high voltage per cell and good capacity life.
Disadvantages are poor low temperature characteristics, it is relatively heavy,
and it cannot be left in a discharged state for too long without being damaged.
Related Batteries: Absorbent Glass Matt (AGM) Gel/Gel Cell Sealed Lead Acid
Lithium:
A primary battery (non-rechargeable) that is quickly entering mainstream
electronic designs, particularly in consumer, portable equipment and
non-volatile memory back up applications where small size, long life and low
cost are the primary requirements. Lithium batteries have superior cold
temperature performance and a shelf life of 5-10 years.
Lithium Ion (Li Ion):
One of the newer rechargeable battery technologies, Li Ion batteries can deliver
40% more capacity than comparably sized NiCd batteries and are one of the
lightest rechargeable batteries available today. Li Ion batteries are the
batteries of choice in notebook computer, wireless telephones and many camcorder
models. They are also one of the more expensive rechargeable technologies.
Load Current:
The discharge current provided by a battery, or drawn by a battery powered
device.
Low-rate Discharge: Withdrawal of small currents for long periods of time, usually longer than one
hour.
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M …………………………………………………………………………………………………………………………..
Manganese Dioxide:
A primary battery (non-rechargeable) similar to that of the alkaline battery
though not as strong in total energy. Available in the same size as Alkaline and
Carbon/Zinc ("AA", "AAA", "C", "D", 9volt) the Manganese Dioxide chemistry is
noted for its ability to retain its charge while being stored at high
temperatures and operates well at temperatures as low as -40°C with little loss
of capacity.
Memory Effect:
Typically only seen in Ni-Cd batteries. It refers to the fact if a rechargeable
battery is used in successive cycles, but not to the full capacity at each
cycle, can lose rest of its capacity at normal voltage level.
Metal Hydride:
An inter-metallic compound or alloy in which hydrogen has been absorbed-, also,
the negative electrode in a nickel-metal hydride battery.
Midpoint Voltage:
The voltage of a battery midway in the discharge between the start of the
discharge and the end voltage.
mAh:
Refers to battery capacity. A 1/1000th of an amp-hour, e.g.: 1.0Ah = 1000mAh.
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N …………………………………………………………………………………………………………………………..
Nickel Cadmium (NiCd):
One of the most proven and historically most widely used rechargeable batteries.
Very dependable and "robust" but contain cadmium and have relatively low
capacity when compared to other rechargeable systems. Very good high rate
discharge capabilities make them very popular in high drain applications such as
power tools.
Nickel Metal Hydride (NiMH): Interchangeable with most NiCd batteries, nickel metal hydride (NiMH) batteries
generally deliver 10-25% greater capacity than NiCds and are environmentally
friendlier than NiCds since they do not contain cadmium. Used in many wireless
phone and camcorders.
Nominal Voltage: The characteristic operating voltage or rated voltage of a battery.
Non-aqueous Batteries: Cells that do not contain water, such as those with molten salts or organic
electrolytes.
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O …………………………………………………………………………………………………………………………..
Open Circuit: Condition of a battery which is neither on charge nor on discharge (i.e.,
disconnected from a circuit).
Overcharge:
The
forcing of current through a cell after all the active material has been
converted to the charged state that is, continued charging after reaching 100
percent state-of-charge.
Overdischarge:
The process of discharging a cell or battery beyond its cutoff voltage and
possibly into voltage reversal.
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P …………………………………………………………………………………………………………………………..
Passivation:
The phenomenon by which a metal, although in conditions of thermodynamic
instability, remains indefinitely unattacked because of modified or altered
surface conditions.
Polarization:
The
lowering of the potential of a cell or electrode from its equilibrium value
caused by the passage of an electric current.
Positive:
A terminal or electrode which has a shortage of electrons.
Positive Temperature:
A thermally reactive device which becomes highly resistive at a specific
Coefficient (PTC) temperature or current.
Primary
Battery:
A battery which is not intended to be recharged and is discarded when the
battery has delivered all of its electrical energy.
Prismatic Cell:
The positive and negative plates are stacked rather than rolled as done in a
cylindrical cell.
Pulse Current:
A periodic current drain of higher than normal drain rates.
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R …………………………………………………………………………………………………………………………..
Rapid Charge:
A charge time that is between slow charge and fast charge (typically 3 to 6
hours for a NiCd).
Rated Capacity:
The number of ampere-hours a battery can deliver under specific conditions such
as rate of discharge, end voltage, temperature. It is usually specified by the
battery manufacturer.
Rechargeable battery:
A galvanic battery which, after discharge, may be restored to the fully charged
state by the passage of an electrical current through the cell in the opposite
direction to that of discharge.
Recondition:
One or more deep discharge cycles below 1.0 volt/cell at a very low, controlled
current. Recondition helps to revert large crystals to small desirable sized,
often restoring the battery to its full capacity.
Recombination: State in which the gasses normally formed within the battery cell during its
operation, are recombined to form water.
Reversal:
The changing of the normal polarity of a battery due to over discharging.
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S …………………………………………………………………………………………………………………………..
Safety Vent:
A venting mechanism designed into a cell which activates under specific
conditions of abuse to relieve internal pressure.
Seal: The structural part of a galvanic cell that restricts the escape of solvent or
electrolyte from the cell and limits the ingress of air into the cell (the air
may dry out the electrolyte or interfere with the chemical reactions).
Secondary Battery:
A battery that can be recharged and reused many times.
Self Discharge:
The loss of useful capacity of a battery on storage due to internal chemical
action (local action).
Service Life:
The period of useful life of a battery before a predetermined end-point voltage
is reached.
Shelf Life:
The duration of storage under specified conditions at the end of which the
battery still retains the ability to give a specified performance.
Slow Charge:
Typically an over-night charge lasting abut 14 hours at a charge current of
0.1C. Battery
does not require instant removal when fully charged.
Smart Battery:
Battery with internal circuit enabling some communication between the battery
and the user. Some batteries feature a capacity indicator only, others offer an
external bus to interface with the equipment the battery power and the
intelligent charger.
Soft Cell:
A cell whose voltage rises above its defined boundaries during charging. This
voltage rise may be caused by high cell impedance as a result of prolonged
battery storage, very cold battery temperature or lack of electrolyte.
Spiral Wound:
An electrode structure of high surface area created by winding the electrodes
and separator into a spiral-wound jelly-roll configuration.
Standby:
The use of batteries in which they are charged by an application to be ready for
use if the primary power to the application fails. Also called float or backup.
Starting Lighting Ignition (SLI)
Battery: A battery designed to start internal combustion engines and to power the
electrical systems in automobiles when the engine is not running. SLI batteries
can be used in emergency lighting situations.
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T …………………………………………………………………………………………………………………………..
Taper Charge: Changing charge current depends
on the status of battery charging. Closer the battery to its full capacity,
lower the charging current.
Temperature Cutoff:
A protective or safety device (e.g., thermostat, PTC, etc.) which senses
temperature in a battery and opens or cuts off the electrical circuit if the
specified temperature is exceeded, thus preventing a further rise in temperature
due to the charge or discharge of a battery.
Thermal Runaway: A phenomena that generate lots of internal heat, caused by high rate charging,
overcharging or other conditions, which can hurt or destroy a battery.
Thermistor:
A temperature sensitive resistor usually made from specially processed oxides
that are used to sense end of charge temperature rises and terminates high rate
charging.
Thermostat:
A temperature sensitive switch.
Top Up Charge:
A low rate charge following the main charge, designed to ensure maximum
capacity.
Trickle Charge:
A charge at a low rate, balancing losses through local action and/or periodic
discharge, to maintain a cell or battery in a fully charged condition.
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V …………………………………………………………………………………………………………………………..
Vent: A sealed mechanism that allows the escape of gases produced during charging and
discharging to escape the battery.
Voltage:
A unit of measuring electrical pressure, all batteries is rated in volts DC
(Direct Current).
Voltage Depression:
An abnormal drop in voltage below expected values during the discharge of a
battery.
Voltage Delay:
Time delay for a battery to deliver the required operating voltage after it is
placed under load.
Voltage-Keyed:
A system that incorporates a mechanical identifier on batteries and devices to
ensure only batteries of the correct voltage are connected to the device.
Voltage Regulator:
A device that regulates the output of a generator or alternator by controlling
the current and voltage.
Voltage Reversal:
The changing of the normal polarity of a battery due to over discharging.
Volumetric Energy Density: The ratio
of the energy output of a cell or battery to its volume (Wh/L).
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W …………………………………………………………………………………………………………………………..
Wall-less Design:
A battery design where the structural support for the cells is formed by an open
plastic framework.
Watt Hours:
A common measurement of energy produced in a given amount of time, arrived at by
multiplying the voltage by the amp hours.
Wet Cell: A cell, the electrolyte of which is in liquid form and free to flow and move.
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Z …………………………………………………………………………………………………………………………..
Zinc/Air:
A primary battery (non-rechargeable) that was commonly used for applications
such as watches and hearing aids. In relation to their physical size, Zinc/Air
batteries store more energy per unit of weight (in terms of 220 Wh/kg) than any
other primary type.
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