A metal alloy (e.g., LaNi5) capable of undergoing a reversiblehydrogen absorption/desorption reaction as the battery is chargedand discharged, respectively. This is the most popular electrodeused in nickel metal hydride batteries.
The taking up or retention of one material by another by chemicalor molecular action.
A primary battery (non-rechargeable) often used in electronicsapplications requiring heavy currents for long periods of time(i.e.: cd players, radios, etc.). Alkaline batteries can deliver50-100% more total energy than conventional Carbon/Zinc batteriesof the same size, hence their popularity in consumerapplications.
A mixture of several other metals or a metal and a non-metal.
A type of generator used in automobiles to produce electriccurrent.
The average humidity of the surroundings.
The average temperature of the surroundings.
The quantity of electricity measured in ampere-hours (Ah) that maybe delivered by a cell or battery under specified conditions.
The electrode in an electrochemical cell where oxidation takesplace. During discharge, the negative electrode of the cell is theanode. During charge, the positive electrode is the anode.
Two or more electrochemical cells electrically interconnected inan appropriate series/parallel arrangement to provide the requiredoperating voltage and current levels. Under common usage, the term"battery" is often also applied to a single cell.
A cylindrical cell design utilizing an internal cylindricalelectrode and an external electrode arranged as a sleeve inside thecell container.
C-Rate (also see Hourly Rate)
Discharge or charge current, in amperes, expressed in multiples ofthe rated capacity. For example, C/10 discharge current for abattery rated at 1.5 Ah is: 1.5 AH/I 0 = 150 mA (A cell's capacityis not the same at all discharge rates and usually increases withdecreasing rate.)
The total number of ampere-hours or watt-hours that can bewithdrawn from a fully charged cell or battery under specifiedconditions of discharge.
A correction factor applied to the rating of a battery ifdischarged under different C-rates from the one rated.
Capacity Retention (or Charge Retention)
The fraction of the fall capacity available from a battery underspecified conditions of discharge after it has been stored for aperiod of time
A primary battery (non-rechargeable) commonly used in low drainconsumer applications (i.e.: clocks, calculators, garage dooropeners, etc.). Available in the same sizes as the Alkaline andManganese Dioxide (“AA”, “AAA”, 9volt, “C”, “D”) the Carbon/Zinc isone of the most widely used dry primary batteries because of itslow cost and reliable performance.
The electrode in an electrochemical cell where reduction takesplace. During discharge, the positive electrode of the cell is thecathode. During charge in a rechargeable battery, the negativeelectrode is the cathode.
The basic electrochemical unit used to generate or storeelectrical energy.
Cells within a battery pack that contain different capacity andvoltage levels.
The stronger cells of a battery (several cells connected inseries) impose a voltage of reverse polarity across a weaker cellduring a deep discharge.
The conversion of electrical energy, provided in the form ofelectrical current from an external source, to restore the chemicalenergy in a cell or battery.
Technique for effectively terminating the charging of arechargeable battery.
The potential or voltage of a battery when it is discharging orcharging.
A process that utilizes a series of heavy discharges and rechargeson a battery to assure optimum performance.
A battery discharge regime whereby the current drawn during thedischarge Discharge remains constant.
A battery discharge regime whereby the current during thedischarge increases as the battery voltage decreases.
A battery discharge regime whereby the resistance of the equipmentload remains constant throughout discharge.
A test in which a battery is discharged to a prescribed end pointvoltage without interruption.
The amount of electricity transported by a current of one ampereflowing for one second.
An inert structure of high electrical conductivity used to conductcurrent from or to an electrode during discharge or charge.
The current per unit active area of the surface of anelectrode.
The current withdrawn from a battery during discharge.
Current Limiting Chargers
A charger that keeps the charge current constant during the chargeprocess but allows the voltage to Fluctuate (typically used on NiCdand NiMh chargers).
The battery voltage at which the discharge is terminated. Thecutoff voltage is specified by the battery manufacturer and isgenerally a function of discharge rate.
A sequence where a charged battery is discharged andrecharged.
Cycle Life The number of cycles under specified conditionsthat are available from a secondary battery before it fails to meetspecified criteria as to performance.
The positive and negative plates are rolled up and placed into acylindrical container (as opposed to stacking the plates in aprismatic cell design).
Depth of Discharge
The ratio of the quantity of electricity (usually in ampere-hours)removed from a battery to its rated capacity.
The opposite of absorption, whereby the material retained by amedium or another material is released.
Electrical current that flows in one direction only. Batteriesproduce direct current as the current flows from a negative to apositive source.
The conversion of the chemical energy of a battery into electricalenergy, and the withdrawal of the electrical energy into aload.
The rate, usually expressed in amperes, at which electricalcurrent is taken from the battery.
The current withdrawn from a battery during discharge.
A cell with immobilized electrolyte. The term "dry cell" is oftenused to describe the Leclanche cell.
Straight battery pack without internal circuits enablingcommunication between the battery and the user.
The operating regime of a battery including factors such as chargeand discharge rates, depth of discharge, cycle duration, and lengthof time in the standby mode.
Discharge or charge power, in watts, expressed as a multiple ofthe rated capacity of a cell or battery that is expressed inwatt-hours. For example, the E/10 rate for a cell or battery ratedat 17.3 watt-hours is 1.73 watts. (This is similar to the methodfor calculating C-Rate.)
The movement of electrons along a conductor.
Weight of a substance that is deposited at an electrode when thequantity of electricity which is passed is one coulomb
The site, area or location at which electrochemical processes takeplace.
The medium which provides the ion transport mechanism between thepositive and negative electrodes of a cell.
Negatively charged particle that orbits the nucleus of anatom.
End Voltage Cutoff
The prescribed voltage at which the discharge (or charge, ifend-of-charge voltage) of a battery may be considered complete.
The output capability of a cell or battery, usually expressed inwatt-hours.
The ratio of the energy available from a battery to its volume(Wh/L) or weight (Wh/kg).
Typical fast charge time for a NiCd is 1 to 3 hours. Thefast-charger detects the state of charge and switches to tricklecharge when full-charge is reached.
The use of batteries in which they are charged by an applicationto be ready for use if the primary power to the application fails.Also called standby or backup.
Similar to trickle charge. Compensates for the self-discharge ona SLA battery
Discharging a cell in a battery, by the other cells or an externalpower source, below zero volts into voltage reversal.
Device used for cutting off an electrical current in the event ofan abusive condition.
The evolution of gas from one or more of the electrodes in a cell.Gassing commonly results from local action (self-discharge) or fromthe electrolysis of water in the electrolyte during charging.
A device that produces an electric current through magnetism.
The ratio of the energy output of a cell or battery to its weight(Wh/kg). This term is used interchangeably with specificenergy.
To connect to the earth or some conductor which takes the place ofthe earth.
Waste which is classified as "hazardous" (i.e.. potentiallyharmful to the environment) by the government.
The standard unit of frequency. A frequency of one complete cycleper second is a frequency of one hertz.
A discharge rate, in amperes, of a battery which will deliver thespecified hours of service to a given cutoff voltage.
A device used to measure the specific gravity of the electrolytein a cell.
Impedance Intermittent Test
Used in terms of the battery's internal resistance a test duringwhich a battery is subjected to alternate periods of discharge andrest according to a specified discharge regime.
The opposition exhibited by a circuit element (cell or battery) tothe flow of an alternating current (a/c.) of a particular frequencyas a result of resistance, induction and capacitance.
Internal Resistance (IR)
The opposition exhibited by a circuit element to the flow ofdirect current (D.C.). In a cell, the internal resistance is thesum of the ionic and electronic resistances of the cellcomponents.
A voltage drop associated with the electrical resistance (R) of abattery or current flow (I). The voltage drop is the product of thecurrent (in amperes) and the resistance (in ohms).
The maximum current drain under which the particular battery willperform adequately under a continuous drain. The rate is based onwhatever drain rate reduces the running voltage to 1.1 volts.
Lithium Ion (Li Ion)
One of the newer rechargeable battery technologies, Li Ionbatteries can deliver 40% more capacity than comparably sized NiCdbatteries and are one of the lightest rechargeable batteriesavailable today. Li Ion batteries are the batteries of choice innotebook computers, wireless telephones and many camcorder models.They are also one of the more expensive rechargeabletechnologies.
Still the most popular battery used today its main application isfor the automobile industry, although it has a growing number ofother applications. Its advantages are low cost, high voltage percell and good capacity life. Disadvantages are poor low temperaturecharacteristics, it is relatively heavy, and it cannot be left in adischarged state for too long without being damaged. RelatedBatteries: Absorbent Glass Matt (AGM) Gel/Gel Cell Sealed LeadAcid
A primary battery (non-rechargeable) that is quickly enteringmainstream electronic designs, particularly in consumer, portableequipment and non-volatile memory back up applications where smallsize, long life and low cost are the primary requirements. Lithiumbatteries have superior cold temperature performance and a shelflife of 5-10 years.
Lithium Ion (Li Ion)
One of the newer rechargeable battery technologies, Li Ionbatteries can deliver 40% more capacity than comparably sized NiCdbatteries and are one of the lightest rechargeable batteriesavailable today. Li Ion batteries are the batteries of choice innotebook computer, wireless telephones and many camcorder models.They are also one of the more expensive rechargeabletechnologies.
The discharge current provided by a battery, or drawn by a batterypowered device.
A primary battery (non-rechargeable) similar to that of thealkaline battery though not as strong in total energy. Available inthe same size as Alkaline and Carbon/Zinc ("AA", "AAA", "C","D",9volt) the Manganese Dioxide chemistry is noted for its ability toretain its charge while being stored at high temperatures andoperates well at temperatures as low as -40癈 with little loss of capacity.
A phenomenon in which a cell or battery operated in successivecycles to the same, but less than full, depth of dischargetemporarily loses the rest of its capacity at normal voltagelevels.
An intermetallic compound or alloy in which hydrogen has beenabsorbed-, also, the negative electrode in a nickel-metal hydridebattery.
The voltage of a battery midway in the discharge between the startof the discharge and the end voltage.
Refers to battery capacity. A 1/1000th of an amp, e.g.: 1.0Ah =1000mAh.
A terminal or electrode which has an excess of electrons.
One of the most proven and historically most widely usedrechargeable batteries. Very dependable and "robust" but containcadmium and have relatively low capacity when compared to otherrechargeable systems. Very good high rate discharge capabilitiesmake them very popular in high drain applications such as powertools.
Nickel Metal Hydride (NiMh)
Interchangeable with most NiCd batteries, nickel metal hydride(NiMh) batteries generally deliver 10-25% greater capacity thanNiCds and are environmentally more friendly than NiCds since theydo not contain cadmium. Used in many wireless phone andcamcorders.
The characteristic operating voltage or rated voltage of abattery.
A measure of resistance that causes one volt to produce a currentof one ampere.
The difference in potential between the terminals of a cell whenthe circuit is open (no-load condition).
The forcing of current through a cell after all the activematerial has been converted to the charged state, that is,continued charging after reaching 100 percent state-of-charge.
The process of discharging a cell or battery beyond its cutoffvoltage and possibly into voltage reversal.
Term used to describe the interconnection of cells or batteries inwhich all the like terminals are connected together. Results inincreased capacity.
The phenomenon by which a metal, although in conditions ofthermodynamic instability, remains indefinitely unattacked becauseof modified or altered surface conditions.
In electricity, the condition of being positive or negative.
The lowering of the potential of a cell or electrode from itsequilibrium value caused by the passage of an electric current.
A terminal or electrode which has a shortage of electrons.
A thermally reactive device which becomes highly resistive at aspecific Coefficient (PTC) temperature or current.
A battery which is not intended to be recharged and is discardedwhen the battery has delivered all of its electrical energy.
The positive and negative plates are stacked rather than rolled asdone in a cylindrical cell.
A periodic current drain of higher than normal drain rates.
A charge time that is between slow charge and fast charge(typically 3 to 6 hours for a NiCd).
The number of ampere-hours a battery can deliver under specificconditions (e.g., rate of discharge, end voltage, temperature);usually specified by the battery manufacturer.
A galvanic battery which, after discharge, may be restored to thefully charged state by the passage of an electrical current throughthe cell in the opposite direction to that of discharge.
One or more deep discharge cycles below 1.0 volt/cell at a verylow, controlled current. Recondition helps to revert large crystalsto small desirable sized, often restoring the battery to it's fullcapacity.
The degree to which the flow of electrons is opposed by thematerial the electrons must pass through. Resistance is expressedin OHMS.
The changing of the normal polarity of a battery due toOverdischarge.
A venting mechanism designed into a cell which activates underspecific conditions of abuse to relieve internal pressure.
A battery that can be recharged and reused many times.
Secure Waste Landfill
A landfill designed for disposal of normal household trash butwhich meets government standards designed to protect theenvironment.
The loss of useful capacity of a battery on storage due tointernal chemical action (local action).
An ionic permeable electronically non-conductive spacer ormaterial which prevents electronic contact between electrodes ofopposite polarity in the same cell.
The interconnection of cells in such a manner that the positiveterminal of the first is connected to the negative terminal of thesecond, and so on, resulting in increased voltage.
The period of useful life of a battery before a predeterminedend-point voltage is reached.
The duration of storage under specified conditions at the end ofwhich the battery still retains the ability to give a specifiedperformance.
An unwanted electrical connection between a negative and positivesource. Short circuits can damage the battery and equipment and cancause sparks or fire.
The initial value of the current obtained from a battery in acircuit of negligible resistance.
A primary battery (non-rechargeable) it is a major contribution tominiature power sources, and is well suited for hearing aids,instruments, photoelectric exposure devices and electronic watches.These cells are primarily made in the smaller “button” sizes.
Typically an over-night charge lasting abut 14 hours at a chargecurrent of 0.1C. Battery does not require instant removal when fully charged.
Battery with internal circuit enabling some communication between thebattery and the user. Some batteries feature a capacity indicatoronly, others offer an external bus to interface with the equipmentthe battery power and the intelligent charger.
A cell whose voltage rises above its defined boundaries duringcharging. This voltage rise may be caused by high cell impedance asa result of prolonged battery storage, very cold batterytemperature or lack of electrolyte.
The ratio of the energy output of a cell or battery to its weight(Wh/kg). This term is used interchangeably with gravimetric energydensity.
The weight of the sulfuric acid electrolyte compared to water.
An electrode structure of high surface area created by winding theelectrodes and separator into a spiral-wound jelly-rollconfiguration.
The use of batteries in which they are charged by an applicationto be ready for use if the primary power to the application fails.Also called float or backup.
State of Charge
The capacity remaining in a battery.
Growth of lead sulfate crystals in Lead-Acid batteries whichinhibits current flow. Sulfation is caused by storage at low stateof charge.
A protective or safety device (e.g., thermostat, PTC, etc.) whichsenses temperature in a battery and opens or cuts off theelectrical circuit if the specified temperature is exceeded, thuspreventing a further rise in temperature due to the charge ordischarge of a battery.
A device at the end of a cell or wire for making a connection toan adjoining cell or wire.
A temperature sensitive resistor usually made from speciallyprocessed oxides that are used to sense end of charge temperaturerises and terminates high rate charging.
A temperature sensitive switch.
A low rate charge following the main charge, designed to ensuremaximum capacity.
A charge at a low rate, balancing losses through local actionand/or periodic discharge, to maintain a cell or battery in a fullycharged condition.
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A unit of measuring electrical pressure, all batteries are ratedin volts DC (Direct Current).
An abnormal drop in voltage below expected values during thedischarge of a battery.
Time delay for a battery to deliver the required operating voltageafter it is placed under load.
A system that incorporates a mechanical identifier on batteriesand devices to ensure only batteries of the correct voltage areconnected to the device.
A device that regulates the output of a generator or alternator bycontrolling the current and voltage.
The changing of the normal polarity of a battery due tooverdischarge.
Volumetric Energy Density
The ratio of the energy output of a cell or battery to its volume(Wh/L).
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A battery design where the structural support for the cells isformed by an open plastic framework.
A measurement of energy, arrived at by multiplying the voltage bythe amperage.
A common measurement of energy produced in a given amount of time,arrived at by multiplying the voltage by the amp hours.
What battery has the longest life, NiMH orLi-Ion?
Lithium-ion (Li-Ion) batteries tend to offer the longest talktimes and standby times in a lightweight package-and tend to be themost expensive. Nickel Metal Hydride (NiMH) batteries are thereliable standard that offer average talk times (2 to 5 hours) andstandby times (24 to 48 hours).
A primary battery (non-rechargeable) that was commonly used forapplications such as watches and hearing aids. In relation to theirphysical size, Zinc/Air batteries store more energy per unit ofweight (in terms of 220 W h/kg) than any other primarytype.