概括單體蓄電池充放電的平均壽命

概括單體蓄電池充放電的平均壽命鑒于相同原材料、同批次的單體電池，容量、內(nèi)阻、壽命等性能參數(shù)符合正態(tài)分布并且離散程度有限；鑒于在相同的電流激勵條件下，單體電池電壓變化過程的一致性漸進(jìn)逼近其它性能參數(shù)的一致性,其中最重要的參數(shù)是荷電程度;鑒于電池在未曾歷經(jīng)過過充、過放的損害，在其生命期里不容易提前失效，可以推斷,如果在充放電過程中通過能量變換的辦法實(shí)施電池組中單體電壓的均衡控制,使單體電壓趨于一致,以單體電池為動力源如移動通訊，電源管理技術(shù)已經(jīng)十分完善，但在蓄電池組中,單體之間的差異總是存在的,以容量為例,其差異性永不會趨于消失，而是逐步惡化的。組中流過同樣電流，相對而言,容量大者總是處于小電流淺充淺放、趨于容量衰減緩慢、壽命延長，而容量小者總是處于大電流過充過放、趨于容量衰減加快、壽命縮短,兩者之間性能參數(shù)差異越來越大，形成正反饋特性，小容量提前失效,組壽命縮短。Asrawmaterials,withthesamebatchofmonomerbattery,thecapacity,internalresistance,servicelifeandotherperformanceparametersconformtonormaldistributionanddiscretedegreeislimited;Givenundertheconditionofsamecurrentincentive,ofmonomerbatteryvoltagechangeprocessconsistency,graduallyapproachingotherperformanceparametersofthedegreeofoneofthemostimportantparameteristhecharged;Lightneverafterhavethechargerandabatterydamage,initslifetimeisnoteasytoearlyfailure,canbeconcludedthatifintheprocessofcharginganddischargingthroughthewayofenergyconversionimplementationofmonomerinthebatterypackvoltagebalancingcontrol,leadtotheagreementmonomervoltage,monomerbatteryaspowersource,suchasmobilecommunications,powermanagementtechnologyhasbeenveryperfect,butinthebattery,alwaysexistdifferencesbetweenmonomer,capacity,forexample,thedifferenceswillnevertendtodisappear,butgraduallydeteriorating.Groupthroughthesamecurrent,incontrast,capacityisalwaysinsmallcurrentshallowfilllightput,capacityofslowattenuation,longevity,andsmallbreastsarelargecurrentchargedischargecapacity,capacityattenuationspeed,shortentheservicelife,performanceparametersofthedifferencesbetweenthetwoismoreandmorebig,theformationofthepositivefeedbackfeatures,smallcapacityfailureaheadoftime,groupshortenedlifespan.2、蓄電池組的充電過程thebatterychargingprocess2.1、充電2.1,charging目前充電主要是限壓限流法,初期恒流(cc)充電,電池接受能力最強(qiáng)，主要為吸熱反應(yīng)，但溫度過低時，材料活性降低，可能提前進(jìn)入恒流階段,因此在北方冬天低溫時,充電前把電池預(yù)熱可以改善充電效果。隨著充電過程不斷進(jìn)行,極化作用加強(qiáng)，溫升加劇,伴隨析氣，電極過電位增高，電壓上升，當(dāng)荷電達(dá)到約70~80%時，電壓達(dá)到最高充電限制電壓，轉(zhuǎn)入恒壓(cv)階段。理論上并不存在客觀的過充電壓閾值，若理解為析氣、升溫就意味著過充，則在恒流階段末期總是發(fā)生不同程度的過充，溫升達(dá)到40~50攝氏度，殼體形變?nèi)菀赘袦y，部分逸出氣體還可以復(fù)合,另一些就作為不可逆反應(yīng)的結(jié)果，損失了容量，這可以看作電流強(qiáng)度超出電池接受能力。在恒壓階段,有稱涓流充電,大約花費(fèi)30%的時間充入10%的電量，電流強(qiáng)度減小，析氣、溫升不再增加，并反方向變化。Chargingatpresentismainlypressurelimitingcurrentlimitmethod,theinitialconstantcurrent(cc)charging,thebatterytoacceptabilityisstrongest,mainlyfortheendothermicreaction,butthetemperatureistoolow,materialactivitydecreased,maybeinadvanceintotheconstantcurrentphase,socoldinwinterinthenorth,thebatterybeforechargingpreheatimprovesthechargingeffect.Withconstantchargingprocess,thepolarizationeffectstrengthen,temperaturerise,alongwithgaschromatography,electrodeoverpotentialincreases,thevoltagerise,whenchargedtoabout7080%,reachedthehighestvoltagelimitingvoltage,chargingintoconstantvoltage(CV)phase.Intheorythereisnoobjectiveofchargingvoltagethreshold,ifunderstoodasanalysis,gasheatingmeansovercharge,theendalwayshappenduringtheconstantcurrentphasevaryingdegreesofovercharge,4050degreesCelsiustemperature,sensorshelldeformationeasily,partoftheescapinggascanalsobecompound,theotherisasaresultofirreversiblereaction,lossofcapacity,itcanbeseenascurrentstrengththanbatterycapacities.Atconstantpressurestage,hassaidatricklecharge,thecostabout30%into10%ofthetime,currentintensitydecreases,gasanalysis,temperaturenolongerincreases,andchangesintheoppositedirection.2.2過充電2.2aftercharging上述過程考慮電池組總電壓或平均電壓控制，其實(shí)總有單體電壓較高者，相對組內(nèi)其它電池已經(jīng)進(jìn)入過充電階段。過充電時，若在恒流階段發(fā)生,由于電流強(qiáng)度大,電壓、溫升、內(nèi)壓持續(xù)升高，若繼續(xù)過充，氣閥打開、溫升繼續(xù)升高、不可逆反應(yīng)加劇。恒壓階段，電流強(qiáng)度較小，過充癥狀不如恒流階段顯著。釀酒設(shè)備只要溫升、內(nèi)壓過高,就伴隨副反應(yīng),電池容量就會減少,而副反應(yīng)具有慣性，發(fā)展到一定程度，可能在充電中也可能在充電結(jié)束后的短時間里使電池內(nèi)部物質(zhì)燃燒,導(dǎo)致電池扌報廢。過充電加速電池容量衰減、導(dǎo)致電池失效，百害而無一利。Consideringaboveaveragetotalbatteryvoltageorvoltagecontrol,actuallythereisalwaysamonomervoltagehigh,relativetoothercellsinthegrouphasenteredthestageofcharging.Beforecharging,exceptintheconstantcurrentphase,duetothecurrentintensity,voltage,temperature,innerpressurecontinuedtorise,ifcontinuetoovercharge,thevalveopens,andirreversiblereactiontemperaturecontinuestorise.Constantpressurestage,thecurrentstrengthissmall,overchargesymptomsthanconstantcurrentphaseisremarkable.Aslongasthetemperaturerise,highinternalpressure,isassociatedwithsideeffects,batterycapacitywillbereduced,andtheadverseeventhasinertia,developmenttoacertainextent,mayinchargemayalsobeinchargeofthebatteryinashorttimeafterthematterinsideburning,leadtodeadbatteries.Chargingspeedbatterycapacityattenuation,leadtobatteryfailure,vileindeed.3、蓄電池組的放電過程thebatterydischargeprocess3.1放電3.1discharge導(dǎo)線電阻和觸點(diǎn)電阻，電壓繼續(xù)下降，經(jīng)過一段時間以后,到達(dá)新的電化學(xué)平衡,進(jìn)入放電平臺期,電壓變化不明顯，放熱反應(yīng)加電阻釋熱使電池溫升較高。放電電壓曲線近似單體放電曲線,持續(xù)放電,電壓曲線進(jìn)入馬尾下降階段，極化阻抗增大，輸出效率降低,熱耗增大,接近終止電壓時停止放電。Wireresistanceandcontactresistance,voltagecontinuestofall,afteraperiodoftime,reachnewelectrochemicalbalance,intothedischargeplateau,voltagechangeisnotobvious,theexothermicreactionandresistanceheatreleasethebatterytemperatureriseishigher.Dischargevoltagecurveapproximationmonomerdischargecurve,continuetodischarge,thevoltagecurveintohorsetaildeclinephase,polarizationimpedanceincreases,theoutputefficiencyisreduced,heatconsumptionincreases,closetotheendstopdischargevoltage.3.2過放電3.2afterdischarge考慮組內(nèi)單體電池，必有相對的過放電情況。在放電后期，電壓接近馬尾曲線，組中單體容量正態(tài)分布，電壓分布很復(fù)雜,容量最小的單體電壓跌落得也就最早、最快，若這時其它電池電壓降低不是很明顯，小容量單體電壓跌落情況被掩蓋,已經(jīng)被過度放電。Considersinglecellsinthegroup,therewillbeaturnhadrelativedischargecondition.Lateinthedischarge,thevoltageisclosetomaweicurve,singlecapacityofnormaldistribution,thevoltagedistributioniscomplex,thesmallestcapacitymonomervoltagesagsaretheearliest,thefastest,ifthebatteryvoltageislowerwhentheotherisnotveryobvious,monomervoltagedropwerehidesmallcapacity,hasbeenexcessivedischarge.觀察單體過放情況，進(jìn)入馬尾曲線以后，若電流持續(xù)較大，電壓迅速降低,并很快反向，這時電池被反方向充電,或稱被動放電,活性物質(zhì)結(jié)構(gòu)被破壞,另一種副反應(yīng)很快發(fā)生,過一段時間，電池活性材料接近全部喪失，等效為一個無源電阻,電壓為負(fù)值,數(shù)值上等于反充電流在等效電阻上產(chǎn)生的壓降，停止放電后,原電池電動勢消失，電壓不能恢復(fù)，因此，一次反充電足以使電池報廢。Observemonomerthroughput,toenterafterhorsetailcurve,ifcontinuedlargecurrent,thevoltagedecreaserapidly,andquicklyreversed,theoppositedirectionofthebatteryischarging,dischargeorpassive,activematerialstructureisbroken,anothersideeffectshappenquickly,overaperiodoftime,batterylossofactivematerialisclosetofull,equivalenttoapassiveresistance,voltageisnegative,thevalueisequaltoreversechargeflowonequivalentresistanceofpressuredropandstopafterdischarge,batteryelectromotiveforcedisappears,thevoltagecan'trecovery,therefore,arevers