Ah, the sin of early adopters. The consequence from Nissan Leaf's engineers bad choice for their first generation EV battery, is now felt years later: The wrath of increased internal resistance (see UPDATE below)!
So far, my first-gen Leaf (i.e. 2012 built) decreased battery capacity (originally 24kWh) is not my biggest problem, thanks to network of fast chargers. The degrading internal battery resistance is!
My real issue is, instead of being able to 'fill' my battery in 6 minutes for a quick top-up of 5kWh, or roughly 30-ish km of range (so I can quickly get back on the road), the degraded battery has also 'slows' down the quick charge capability considerably. More than twice as long!
Prodding into cells' battery voltage during fast charge, revealed that the BMS deliberately slows down the charger in order to maintain cell battery voltage under 4.1 Volt at any stage. Fair enough. One can expect this 'slowing down' when the battery is closer to fully charged (i.e. 80% SoC or above). Due to massive degradation of 'Hx', this now happens very early on mine (under 50% SoC). Yikes!! (see UPDATE below)
I just never thought the 'Hx' degradation griefs me equally as the 'SoH' degradation. Sad.
Looking at the bright side (so I can feel better), other than batteries, Nissan Leaf is such a good car (said me who treat cars like a fridge, i.e. purely utilitarian). Definitely no disappointment to date (except the battery...)!
My battery history so far:
Nomenclature buster:
BMS:
Battery Management System.
SoH:
State of Health is another indication of the battery's ability to hold and release energy and is reported as a percentage. When the battery is new SOH=100%.
SoC:
State of Charge indicates the amount of charge currently in the battery.
Hx:
The meaning of this number is not fully understood but it appears to be inversely related to the battery internal resistance. As the internal resistance of the battery pack increases it is thought this percentage decreases. As internal resistance increases more energy is lost within the pack and the pack heats up more under load.
UPDATE 24 June 2019:
I had another fast charge session from 20%SoC, and I was expecting the 50kW charge lasted longer. I was wrong. After self-research, I've just found out something called polarisation effect. So, the aging of my Leaf battery grief is mostly due to this, not internal resistance.
Presented below in equivalent circuit. There you go!
So far, my first-gen Leaf (i.e. 2012 built) decreased battery capacity (originally 24kWh) is not my biggest problem, thanks to network of fast chargers. The degrading internal battery resistance is!
My real issue is, instead of being able to 'fill' my battery in 6 minutes for a quick top-up of 5kWh, or roughly 30-ish km of range (so I can quickly get back on the road), the degraded battery has also 'slows' down the quick charge capability considerably. More than twice as long!
Prodding into cells' battery voltage during fast charge, revealed that the BMS deliberately slows down the charger in order to maintain cell battery voltage under 4.1 Volt at any stage. Fair enough. One can expect this 'slowing down' when the battery is closer to fully charged (i.e. 80% SoC or above). Due to massive degradation of 'Hx', this now happens very early on mine (under 50% SoC). Yikes!! (see UPDATE below)
I just never thought the 'Hx' degradation griefs me equally as the 'SoH' degradation. Sad.
Looking at the bright side (so I can feel better), other than batteries, Nissan Leaf is such a good car (said me who treat cars like a fridge, i.e. purely utilitarian). Definitely no disappointment to date (except the battery...)!
My battery history so far:
Nomenclature buster:
BMS:
Battery Management System.
SoH:
State of Health is another indication of the battery's ability to hold and release energy and is reported as a percentage. When the battery is new SOH=100%.
SoC:
State of Charge indicates the amount of charge currently in the battery.
Hx:
The meaning of this number is not fully understood but it appears to be inversely related to the battery internal resistance. As the internal resistance of the battery pack increases it is thought this percentage decreases. As internal resistance increases more energy is lost within the pack and the pack heats up more under load.
UPDATE 24 June 2019:
I had another fast charge session from 20%SoC, and I was expecting the 50kW charge lasted longer. I was wrong. After self-research, I've just found out something called polarisation effect. So, the aging of my Leaf battery grief is mostly due to this, not internal resistance.
Presented below in equivalent circuit. There you go!
