Preperation Of New Expanders And The Influence On The Performance Of Lead–acid Battery

In recent years,it is accepted that the key technology of electric vehicles is power supply.Lead-acid battery is one choice of commercial power source for EV,because of its mature in technology,low price and high safety.Battery for EV usually operated under high rate partial state of charge.Large PbSO₄ crystals will be accumulated on the surface of the negative plate under such conditions with the traditional lead-acid battery.The hard PbSO₄ crystals layer of the negative plate will reduce the charging efficiency,shorten the cycle life,and finally lead to the failure of battery.The mode of failure is known as"negative plate sulfation effect".Developing new types of negative expander suitable for lead-acid battery is the key in research.Three aspects work has been completed in present article which is introduced as following.1.Bamboo shoots shell biomass as raw material,was treated by pre-carbonization,grinding,sieving and activated with zinc chloride at800℃under N₂ atomosphere.Bamboo shoots shell charcoal（BS-C）was prepared.The BS-C/Pb（II）composite was then prepared by in situ impregnation precipitation method.The phases composition and microstructure were characterized by XRD,SEM,EDS and laser particle size analyzer.The results showed that BS-C/Pb（II）were formed evenly with the size of PbSO₄ crystals being 50¹00nm.The mass fraction of Pb in the composite was 25.47%.The BS-C and BS-C/Pb（II）electrodes were tested by cyclic voltammetry and LSV with tri-electrode cell.0.2（m）%BS-C and BS-C/Pb（II）was added to the lead-acid battery negative plate respectively.The battery was prepared by conventional paste mixing,paste coating,plate curing and cell formation.The cycle life of battery with BS-C/Pb（II）was 80 cycles longer than BS-C and the discharge time increased 2.5 min under 1C discharge mode.2.Carbon nanotubes（CNTS）was provided by Advance Nanopower INC（ANP）which was used as the raw materials for Pb（PbO）/CNTS.CNTS was treated by Pb（II）adsorption,in situ deposition and reductive decomposition.XRD,EDS,SEM techniques were adopted to identify the phase composition and microstructure.The results showed that nanoscale Pb,PbO particles were dispersed uniformly on the surface and inner pipe clusters of CNTS.CNTS and Pb（PbO）/CNTS were used to prepare tested electrodes respecctively.The result of test showed that CNTS had good electrical conductivity.The mass fraction of 0.2%CNTS and Pb（PbO）/CNTS was added to the lead-acid battery negative plate respectively.The battery was prepared by conventional paste mixing,plate coating,plate curing and cell formation.The cycle life of battery with Pb（PbO）/CNTS is 40 cycles longer than that of battery with CNTS and the time of discharge increased 3min under 1C discharge mode.3.The lignin sulfonate provided by Jilin Yanbian Shixian Bai Lu Paper Co.Ltd.was used as the raw material which was treated further by sulfonated methylation modification and a kind of modified lignin sulfonate was prepared.SEM and IR spectrometry were adopted to identify the microstructure and composition.The results showed that the amount of sulfonic group of modified lignin sodium sulfonate was increased significantly.The sulfonic degree of modified lignin sodium sulfonate is 0.82mmol/g,tested by ion exchange and electrical conductance titration technique.0.2（m）%lignin sulfonate and modified lignin sulfonate was added to the paste of lead-acid battery negative plate respectively.The battery was prepared by conventional paste mixing,plate coating,plate curing and cell formation.The cycle life of battery with modified lignin sulfonate was 80 cycles longer than that of battery with lignin sulfonate and the low temperature capacity was increased12%.The time of discharge increased 2.1 min.under 1C discharge mode.