Assessment of Second Life of Lithium Iron Phosphate Based Batteries

Relevant international standards such as IEC 61982-2 and the forthcoming IEC 62660-1 specify that the end-of-life of a battery is attained when the actual battery capacity is reduced to 80% of its initial capacity. Instead of being scrapped for recycling, it may be interesting to recover the remaining value of these batteries by using them in other applications at the end of their automotive service life, such as in grid energy storage, renewable power management, vehicle applications for which the residual capacity of the battery is suitable, as well as UPS batteries. In this paper, the different options for the second life of lithium iron phosphate based batteries are investigated and presented. From figure 1, it is clear that the reduction of the discharge capacity has a linear gradient until a certain point (about 100 cycles). Moreover, the results show that the cell capacities maintain a stable character in the region between 100 -600 cycles, with exception cell number 3.
In this paper a full analysis, whereby a number of innovative proposals concerning the energy efficiency (in a second life stage) will be included taking into account the Peukert effect and proposomg new load profiles for second life phase. The latter issue can be considered as a key consideration in the field of battery standardization. Finally, the impact of the second life usage on the effective price on the battery electric vehicles and hybrid electric vehicles is studied.