This question comes to the minds of many when considering to shift upon or buy an EV vehicle. Unlike vehicles powered by a gasoline engine, an EV is solely powered by a set of rechargeable batteries that drives the motors connected to the wheelset of the car.
In theory, it is a simple machine consisting of few components but when it comes to the practicality of shifting to or driving an EV a number of questions arise in our mind and the most important is the life span of the most important component; the battery.
The general question of How long does Electric car battery lasts can’t simply be answered in one word or numeric number as a number of factors determine the total life span of a battery.
The battery is an active component in an EV, which has active chemistry inside it and a battery management system (BMS) attached to it to observe and keep a track record of chemistry operations for instance charging, discharging, or the temperature point of a specific battery cell.
The life span of an EV battery is first determined by the manufacturer, based on different chemistries, in terms of a number of charges and discharge stable cycles.
For optimum performance the manufacturer lets the battery undergo rigorous testing before determining the usability and commercial viability of certain battery chemistry or its type.
If a battery cell shows stable cycling behavior to a specific cycle number it is considered its stable cycle life, it can be 100 cycles or up to 10000 cycles depending upon battery chemistry and its type.
There are a number of battery chemistries readily available in the market for suitable uses. The most common battery chemistries are lithium-ion and lithium iron phosphate (LifePO4).
As it is clear from the name of these battery chemistry that one is limited to lithium-ion and the other is a composite of lithium, iron, and phosphate metal.
Here comes the important point, both are batteries, why choose one above the other, and how the overall life of a battery is impacted by selecting different battery chemistries for specific purposes.
The answer to this question is the battery has a limited life and it has a limited capacity to power the appliance. When a single charge and a discharge cycle are completed the battery loses some of its ability to store the total charge in the next cycle, usually just a very tiny fraction of overall capacity,
but in long run, this fading behavior has a limiting impact on the battery life. During several hundred cycles of operation the decline in charge storage can be well witnessed and there comes a point when a battery is considered underperforming, usually less than 80% performance, and hence deemed unstable and end of stable working life.
So it is clear now that the number of cycles defines the life span of the battery.
If one whole cycle is done in a single day then a battery having 5000 stable cycles can last up to 5000 days of working life. Now different chemistries have different advantages over one another,
for instance, lithium-ion can deliver excess amounts of power but it is prone to high temperature and it poses a fire threat. Whereas, lithium iron phosphate (LifePO4) has a high capacity retention ability but cannot deliver as much power.
Also, the manufacturing cost and commercial viability are very different for specific battery types. So whenever you wish to buy or upgrade to an EV and are worried about the battery life of the car just remember the simple formulae i.e. to know the number of stable cycles which a battery can deliver and keep in view your usability you can calculate to predict the precise life span of the battery.
How safe are electric car batteries
The most important aspect during the operation of any device or machine is its safety features to protect against accidents and ensure reliable working.
When it comes to car batteries we know that for a long time it has been a part of debate whether car batteries are safe enough for common use or not.
The good news is that modern technology is catching up to the safety standards set by the industry regulators and tremendous improvements with respect to safety standards of car batteries have been made to date.
In general, we can say that batteries are safe enough for common use but nevertheless, this delicate piece of technology has some critical limits that must not be breached in order to stay in the safe zone.
The first and most discussed safety aspect for the batteries is fire safety. In the past, a number of issues related to car battery failures have been documented but the most damaging and up to a life-threatening point is the fire safety in the car batteries.
From the literature review, we have extracted a couple of key points that play a vital role in causing a fire in a battery. You can learn these points and make sure to avoid such conditions and stay in a safe zone for as long as the battery completes its natural life cycle.
As we know the battery has active chemistry going on in between two opposite electrodes of the battery.
This simple chemistry can turn lethal if an external stimulus becomes favorable for an unwanted chemical reaction.
The number one parameter responsible for this unwanted situation is the temperature of the car battery. If the battery temperature exceeds a critical limit because of internal or external conditions the things can go out of control in no time.
All the high concentration of charge is leashed out resulting in a fire. In a minor case, the cells are observed to inflate which is the direct result of unwanted reaction having gaseous by-product.
If still, the reaction goes on there comes a point where the individual cell cannot retain the pressure and it punctures. Highly flammable gases such as hydrogen are released in no time and instantly catch fire.
It is advised that if you observe an abnormality in cells you must go for an inspection.
Another important thing is the uncontrolled charging and discharging or overcharging of battery cells. When uncontrolled discharging is made a tremendous amount of current and voltage flow out of the cells causing great stress on the battery.
This leads to material degradation and inflation inside the cell. Repeated occurrences of such reactions eventually lead to battery failure in long run.
Electric Car Battery Management System
The safety feature added to current batteries in this regard is the addition of intelligent battery management systems.
These systems often called battery management systems or BMS is integrated circuits attached to a number of sensors that monitor not only the temperature variations but also the chemical profile of the battery during the charging and discharging process.
If the battery shows abnormality during any cycle the battery management system instantly gives an alert. In another case, if the temperature rises above a certain preset limit the BMS automatically shuts off the functioning of the battery to ensure minimum impact of the outcome.
As of the year 2020, new car battery systems are well insulated to take minimum effect from external temperature changes.
Moreover, the raw materials being utilized recently are of a more high standard and high purity so as to not provide the necessary elements required to trigger unwanted reactions in a battery cell.
All in all new car battery systems are more insulated, more efficient, and equipped with battery management systems to monitor battery health and working behavior in real time within safe limits.