铅酸电池知识.doc

铅酸电池知识.doc铅酸电池知识Standers-byseemorethangamesters・Thesettingsunisinfinitelygood,justneardusk・Greenhillscannothide,afterall,-up・eghosts,angrypoemsseektobundleaknife・Voltageandchargedischargecharacteristicsofleadacidbatteryelectromotiveforceandopencircuitvoltageoflead-acidbatteries1electromotiveforcedefinitionWhenthebatteryisopen,thedifferencebetweenthepositiveelectrodebalancepotentialandthenegativeelectrodebalancepotentialisdeterminedbythereactioninthebattery,:E=Etheta+RT/nFlna(H2SO4)/a(H20)TypeE一一electromotiveforceofbatteries;Etheta一theelectromotiveforceatwhichtheactivityorpressureofallreactantsisequalto1iscalledthestandardelectromotiveforce(V);R一molargasconstant,/(Kmol);T一temperature(K);F-Fala,sconstant(96500C/mol);N-thenumberofelectronslostinelectrochemicalreactions・,thehighertheelectromotiveforce,themoreenergythebatterycantheoreticallyoutput,andthehigherthepracticalvalue・ElectromotiveforceTheelectromotiveforceisalsoequaltothedifferenceoftheequilibriumpotentialofthetwoelectrodesthatmakeupthebattery,thatis,E二,Phie,+Phie,・Ametalelectrodeisinsertedintoasolutioncontainingthemetalion,becausetheioninthemetalisdifferentfromthechemicalpotentialinthesolution,sothatthemetalionistransferredbetweentheelectrodeandthesolution・Understaticelectricity,thistransferrapidlyreachesdynamicequilibrium・hargeofoppositesign,equaltothenumber,sotheformationofelectricdoublelayerattheinterfacebetweenelectrodeandsolution,correspondingtotheestablishmentofelectricdoublelayer,electrodedndsolutionisproducedbetweenapotentialdifference,calledequilibriumelectrodepotentiaLThesignandvalueoftheelectrodepotentialdependonthetypeofmetalandtheconcentrationofio