Influence Of Carbon Additive On The Performance Of Lead-acid Battery Negative Plate

In view of the insufficient resources and the worrying environment, people paymore attention to the hybrid electric vehicle(HEV), which can lead to energyconservation and emission reduction. The lead-acid battery is one of the mostpotential energy storage for its high technical maturity, steady performance, low cost,great cycling performance under the High-rate partial-state-of charge(HRPSoC)operation with adding carbon materials to the negative plate.Firstly, we found that graphite has best conductivity, the carbon black hasbiggest special surface area, thus the performance carbon additive has the biggestpore volume and best capacitance properties. Then we studied the infuence ofdifferent carbon on the cycling performance of lead-acid battery under the HRPSoCregime. The results showed that0.5mass%graphite improves the life to3807times,a little longer than commercial battery whose life is3342times.1.0mass%carbonblack improves the life to9094times and1.0mass%performance carbon additiveimproves the life to8285times. What’s more, carbon black and performance carbonadditive can improve batteries’ dynamic charge acceptance obviously, whileaccelerate the hydrogen evolution of nagetive plate.Then we mixed two of the three types of carbon together to study the mixedcarbon materials’ influence on the performance. The results showed that whenadding0.3mass%graphite and0.7mass%performance carbon additive, the batteryhas the longest life, which is up to13991times. The mixture of three carbonmaterials can improve battery’s cycling life up to11435timesTo reduce hydrogen evolution, Sn and the mixture of Sn and Pb were depositedon the carbon materials using NaH2PO2as reducing agent before adding to thenagetive plate. The results showed that Sn can reduce the rate of hydrogen evolutionand improve cycling life to16435times. The mixture of Sn and Pb can significantlyreduce the hydrogen evolution rate, inhibite the sulfation of the nagetive plate，andthe cycling life is increased to28847times. The charging voltage is as low as2.3Vand the dynamic charge acceptance is great.The quality of Sn is about0.070mass%of PbO, while the quality of Pb is about0.072mass%of PbO.Lastly, we analysised the mechanism of the graphite/performance carbonadditive. Graphite can improve the conductivity of performance carbon additive toform a good conductive network. Performance carbon additive’s big special surfacearea and porous structure can supply more electrochemical reaction area. When thebattery is discharging, the generated PbSO4can attach to the carbon surface moreeasily to suppress the growth of PbSO4. When the battery is charging, carbon materials transfer electrons to PbSO4, reduced to Pb easily. What’s more, thegenerated Pb attach to the carbon surface, keeping the nagetive active materials inloose structure to maintain high electrochemical activity. What’s more, thecapacitance properties of performance carbon additive can share a part of currentwhen the battery is charged under the HRPSoC regime to improveperformance.With the additon of Pb and Sn, the hydrogen evolution rate of carbon isdepressed effectively, and the cycle life of lead-acid battery is improved to28847times, which meets the requiement of HEV to energy storage.