Attempts to make electric vehicles even more viable than present are ongoing and they basically focus on two factors. One is to enable them with high energy density batteries for a longer range. The other, is to reduce the charging time of these batteries using super chargers. A new research now suggests that the latter might not be a very good practice and can actually kill your car battery much faster.
Engineers from the University of California, Riverside (UCR) have come up with a new research that suggests that the commercial battery fast-charging stations cause the EV batteries to endure high temperatures and resistance. These extremities for the batteries can cause the cells to crack and leak thus losing their storage capacity.
In fact the highlighted potential damage is so much with the industry standard fast charging process that it can reduce a battery¡¯s capacity by as much as 40% after 40 charge cycles. It further stated that within 60 such charge cycles, the cells began to crack, exposing the internal components. In extreme cases, this can be a potential cause of fire.
To validate their research, the engineers designed an experiment around a set of Panasonic lithium-ion cylinder cells, ones that are used in Tesla¡®s power packs. The researchers first charged the set of cells using the method which is used in commercial fast chargers.
Then they charged another set of cells using a new algorithm-based protocol that charges the batteries as fast as possible but only up to a limit. The limit is set as per the internal resistance of the battery, cutting off the charging supply as soon as the internal resistance of the cell gets too high.
For those unaware with the term, internal resistance of a battery resists the current flow when the battery is connected to a circuit. Due to this internal resistance of a cell, some of the electrical energy flowing through it is converted to heat energy. So it is only understandable that a high internal resistance in a battery can cause problems when charging at high speeds.
As per the researchers, it is this internal resistance of a battery that goes unaddressed during fast charging and can potentially lead to permanent damage to the batteries.
To prevent this damage, the team proposed a charging method just as they used in the second round of experiment. The idea is to cut off the charging of a battery as and when its internal resistance gets too high.
This ¡®internal resistance based¡¯ charging method also helped in prolonging the life of the battery cells. In the above experiment, the method only led to a 20% reduction in battery capacity over the same 40 charge cycles.
Other suggestions handed out by the researchers include a minimum use of commercial fast chargers. They even suggest that an EV should be charged before its battery is totally empty and should not be overcharged in any way. An ideal practice is to charge it till 90% of the total capacity.