EV Batteries do degrade due to many different reasons, we consider two common aspects that happen in Sri Lankan conditions and how a battery exercise may help. Please note that the content is still under discussion among specialists, so you may need personal/professional supervision.
There are many wrong usage practices of the EV s in Sri Lanka causing battery degradation and even wrong calibrations. We have spoken of battery preserving tips, ere is a link: https://mobility.lk/2019/05/12/use-ev-battery-for-long/
But the ones which have not being used well and/charged will undergo degradation. Follow this too: https://mobility.lk/2019/10/03/mandatory-battery-tip/
The main reason we experience a capacity loss with aging is due to SEI thickening and electrolyte consumption. This process consumes lithium ions and electrons irreversibly hence, capacity degradation.
Another major reason behind the capacity loss is the loss of electron movement. This is called lithium plating. Simply the electrons get collected onto the anode preventing its travel which causes capacity loss (not the only).
Lithium plating happens mostly during the fast charge at high SOC which means simply lithium ions deposit in metal form on the graphite surface. Lithium metal reacts with electrolytes hence you lose capacity. This process is much faster. Therefore, you should experience a rapid capacity loss.
The longer a battery stays at high SOC, the more lithium plating occurs, and the more capacity is lost.
What can you do to recover?
Leave the SOH between 20% to 40% for a month or two. Let the ions get detached and back in action
Tough? you may run if it’s a must, but give only the bare minimum charge.
Do either a deep discharge, rapid discharge, and/or a fast discharge at a reasonably high temperature. Normally a fast charge should be done only up to reasonable SOC (below 80 %) to avoid lithium plating.
The recovery effect is not fully understood and needs further research. And we do not take any responsibility for success or failure.
Atop the degradation, the smart batteries (digital) may release erroneous data, where your BMS will interpret and CAN will display differently.
To correct this error, we advise a re-calibration.
Discharge the battery from 100% to 10% at a gradual and even pace. Then go for an L2 charge. Measure now.
Also try discharge the battery from 100% to 10% on a gradual and an even pace. Then go for a L3 charge.
We may try this for multiple times, under the observation and monitoring with the instrument cluster data on efficiency, temp and also the leaf spy data on internal resistance, temperature, SOH and more.
You got to understand that these procedures may result differently based on your type of EV, usage, cause/s of error, battery status. So please proceed with your own discretion.
The conditions are different in Sri Lanka although we referred several technical papers done overseas.
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