Automakers are increasingly turning to lithium iron phosphate battery (LFP) for affordable electric vehiclesand packs with that chemistry may benefit from a different charging regime than that typically used for the currently dominant nickel manganese cobalt (NMC) chemistry.
As noted in a recent Engineering Explained video, automakers recommend different best practices for their LFP-equipped electric vehicles. For example, the Ford Mustang Mach-E owner’s manual states that it’s best to set the maximum charge level to 100% and charge to that level at least once a month. Tesla has also Recommended to charge LFP equipped vehicles to 100%This is contrary to normal best practice for NMC equipped vehicles.
2024 Ford Mustang Mach-E Race
That’s because charging an LFP battery to 100% helps calculate the remaining charge, which is usually done based on voltage. LFP batteries have flatter voltage curves, meaning they have roughly the same voltage for different states of charge. But charging to 100% causes a voltage spike that acts as a marker to identify the state of charge.
However, a recent study published in Journal of the Electrochemical Society Note that higher states of charge lead to more battery degradation. State of charge was found to be the “most important factor” influencing capacity loss, with higher states of charge accelerating the process.
That leads Engineering Explained to recommend that EVs with LFP batteries should only be plugged in when necessary. The same study also noted less degradation in LFP batteries charged from 0%-100% compared to 75%-100%. So it’s best to avoid smaller charge cycles with high starting capacities with LFP batteries, which isn’t necessarily the case with NMC cells. But it’s important not to go overboard and let the battery drain to 0%, which can permanently damage the cells.
Such advice will become more relevant as more automakers begin using LFP batteries in electric vehicles in the U.S. market. In addition to Ford and Tesla, for example, Rivian has discussed plans to use LFP batteries in the near future. These batteries are not found in recently launched models. Cheaper versions of R1S and R1T as predicted
