Preparation And Electrochemical Performances Of Phosphate-Based Lithium-ion Batteries

As power lithium ion battery marketing,phosphate power lithium ion batteries due to widely attention has long cycle life and high security,the performance of the monomer,the corresponding cell system also getting more and more application in electric vehicles,but the consistency of monomer battery and environmental adaptability(discharge performance in high temperature and low temperature discharge performance)still needs to be improved.Based on this,the preparation technology and electrochemical properties of lithium iron phosphate and lithium vanadium phosphate batteries are studied in this paper.Study of lithium iron phosphate material,conductive agent,electrolyte and diaphragm effect the performance of the flexible packaging full battery,get material selection principle,the results showed that the moderate D 50 smaller particle size,specific surface area and carbon content is more than 2% of the lithium iron phosphate material has better circulation and ratio performance;The electrolyte with high lithium concentration has better circulation,magnification and low temperature discharge performance.The composite conductive agent containing nanotubes has better circulation,multiple discharge performance and more stable discharge platform.The membrane with large porosity and large water contact Angle has better discharge efficiency,and the thermal effect of the battery is smaller.Preferred battery materials,bulk soft packing batteries,lithium iron phosphate was prepared more than 8000 battery test results show that the standard deviation by 133 mAh capacity to reduce to 86 mAh,internal resistance standard deviation by 0.191 m ? reduce to 0.082 m ?,significantly improve the flexible packaging battery consistency;The cycle life increased from 2000 times to 3600 times(the capacity decreased to 80% at 1C multiplier),and the 10 C times discharge capacity reached 99% of the 1C discharge capacity.55 ? environment,charge at 1.0 C,1.0 C discharge 100% DOD deep cycle life reached more than 1000 times;At 20 ? and current density of 0.5 C to devolve electricity,can emit 65% of capacity at room temperature;Also by using XRD and SEM analysis after the cycle sheet material structure and morphology,the results show that the circulation after the lithium iron phosphate material crystal structure did not collapse,did not appear impurity phase,morphology change is small,the capacity of the battery drop the main reason is that the cathode and electrolyte.Through optimizing vanadium lithium phosphate materials,optimization of the anode paste formula,and the research on the properties of vanadium phosphate lithium battery electrolyte,get soft packing lithium vanadium phosphate battery preparation technology,active substances: binder,conductive agent 91.5:5:3.5 best proportion,VC,PS additive of high voltage improved significantly the cycle of vanadium phosphate lithium battery electrolyte performance.Using lithium vanadium phosphate preparation technology,bulk soft packing batteries,lithium vanadium phosphate was prepared by more than 4000 battery test results show that the standard deviation by 125 mAh capacity drops to 86 mAh,internal resistance standard deviation by 0.125 m ? reduce to 0.078 m ?,significantly improve the flexible packaging battery consistency;The deep cycle life of DOD reaches 800 times(the capacity decreases to 80% at 1C multiplier).At the same time,the vanadium phosphate lithium battery has more excellent low temperature performance than lithium iron phosphate battery,in-30 ? and 0.5 C,the current density of discharge can still emit 71.40% of capacity at room temperature.Using XRD and SEM analysis of circular pole piece after material structure and the morphology,the results show that the vanadium lithium phosphate material circulation process is not easy to produce stress,but not completely transition metal REDOX capacity losses may be caused.