Life Cycle Assessment And Cascade Utilization Research Of Vehicle Power Batteries

As the core components of new energy vehicles,clarifying the resource and environmental impacts during the life cycle of power batteries can provide an effective reference for the establishment of an energy conservation and emission reduction assessment system for the whole life cycle of power batteries.At the same time,with the increase of the number of new energy vehicles,power batteries have entered a large-scale retirement period.Evaluating the resource and environmental benefits of the cascade utilization of retired power batteries can provide a scientific basis for the improvement of the management system for retired power batteries and related standards for reuse.Therefore,based on the life cycle assessment method and power battery assessment model,this paper carries out research on the whole life cycle assessment and cascade utilization of vehicle power batteries,with the specific contents as follows:Firstly,based on the perspective of "cradle to rebirth",this paper analyzes the life cycle assessment method,and makes clear the content framework and practical significance of the life cycle assessment method.Four types of power batteries are selected as the research objects,namely,lithium iron phosphate battery(LFP),nickel-cobalt-manganese lithium battery(NCM),lithium manganese battery(LMO)and lithium titanate battery(LTO).The four power batteries are divided into four stages: raw material acquisition,production and manufacturing,assembling,and recycling.Based on the mathematical assessment models of the four power batteries,a list of materials and energy consumption datas required for modeling each life cycle assessment stage of the power batteries is sorted out and obtained,and four life cycle Ga Bi assessment models for LFP,NCM,LMO,and LTO power batteries are established.Secondly,on the basis of the life cycle assessment method and assessment model,the results of life cycle resource depletion and environmental impact of four power batteries are compared and analyzed,and the potential resource depletion ranking and potential environmental impact ranking(LFP<LMO<NCM<LTO)of four power batteries are obtained.At the same time,the power batteries are matched with battery electric vehicles respectively,and the life cycle assessment results of pure electric vehicles under different clean energy power generation ratio,different power battery charging efficiency and different power battery recycling technology are compared and analyzed.It is found that increasing the ratio of clean energy power generation and optimizing the charging efficiency of power batteries can effectively reduce the potential of resource consumption and environmental emissions in the life cycle of battery electric vehicles.Compared with the LFP-physical recycling,NCM-hydrometallurgical recycling and NCM-pyrometallurgical recycling,the life cycle resource consumption potential and environmental emission potential of battery electric vehicles by LFP-hydrometallurgy recycling are the smallest.Finally,retired lithium iron phosphate battery is selected as the research object.Based on the 50% cell conversion rate(CCR),the life cycle mathematical assessment model and Ga Bi assessment model of reconstituted lithium iron phosphate batteries and replacement lithium iron phosphate batteries are established respectively.The characterization assessment results show that the cascade utilization stage of lithium iron phosphate batteries can generate the positive benefits of 76% of ADP(e)and 83% of ADP(f),as well as 94% of GWP,93% of AP,84% of EP,92% of POCP,98% of HTP,and 33% of ODP.Considering the sensitivity of life cycle assessment indicators and their benefit percentages to cell conversion rates(30%,40%,50%,60%,70%),it was found that ODP has the highest sensitivity to CCR,while assessment indicators such as HTP,AP and GWP have relatively low sensitivity to CCR,and HTP,AP and GWP have high benefit percentages at different CCR.