December 01, 2023
Battery degradation in EVs
Ever tried squeezing a sponge that’s been used and wrung out countless times? You will notice it doesn’t hold or absorb water like it once did. Over time, much like that weary sponge, batteries in our electric cars can’t retain their charge as robustly as when they were brand new.
Battery degradation in EVs
Table of contents
This phenomenon is referred to as battery degradation, and it’s an essential topic every EV owner should be familiar with. Understanding it is crucial because it directly affects both the performance and longevity of your electric car.
As your EV’s battery degrades over time, it gradually reduces the distance it can travel on a single charge, diminishing its range. This, in return, can lead to more frequent stops at charging points and a longer charging process, extending your travel time.
Learning about battery degradation empowers you with strategies to minimise its impact. By implementing measures to preserve battery health, you not only enhance your EV’s resale value but also reduce the environmental footprint associated with battery replacement or extended electricity consumption.
This article will explore the two main culprits behind battery degradation: calendar ageing and cyclic ageing. And if you’re wondering how to keep an eye on your EV battery’s health, our EV Health Checker is designed to offer you a clear picture of the condition of your battery.

The science behind degradation

On the scientific front, lithium batteries are made up of individual cells, each containing a positive electrode (cathode) and a negative one (anode). During charging and discharging, lithium ions move between the anode and cathode, hence producing the power needed for your vehicle.
Throughout this process, various chemical reactions and physical changes occur inside the battery that lead to a loss in lithium ions and reshaping of the battery’s chemical structure. It’s akin to our sponge becoming damaged, filled with tiny bits of dirt and small parts breaking off.

Calendar ageing

One unavoidable aspect of EV battery degradation is calendar ageing. Just like humans, lithium batteries can’t stand the test of time: they have a lifespan and grow old naturally, losing the capacity to hold as much power. And as our lifestyle choices can affect how quickly we age, the same is true for your electric car battery.

1. The effect of temperature

During operation, an EV battery ideally needs an ambient of 20-30 degrees Celsius. But let’s be real - without the powers to control the weather, providing such consistent conditions is a challenge. Luckily, electric car technologies have come up with some smart solutions like advanced thermal management systems to prevent accelerated degradation.
Now, when your battery isn’t in use, it actually prefers cooler temperatures. It might not be practical to build a refrigerated garage for your electric car, but choosing a shaded parking spot is a simpler step you can take to prolong your battery’s health.

2. The effect of storage charge level

Storage habits also matter. Keeping your battery fully charged during long periods of inactivity puts unnecessary strain on it. Imagine your battery as if it were your stomach after a big meal. It will make you feel uneasy if you do not do any physical activity and do not give your stomach a break from eating after small digestion. Instead, allowing your battery to rest at a lower state of charge, typically around 30%, is similar to how your body feels better after eating in moderation.
However, the practicality of maintaining a lower state of charge (SoC) depends on your usage patterns. If you plan to leave your EV unused for an extended period, such as a holiday, keeping it at 30% charge is feasible and beneficial for the battery’s health.
But for short periods of inactivity, like overnight parking, you might want to be prepared for your next drive. Still, even in that case, avoiding overnight charges and optimising your battery’s health by maintaining the charge level at 80% maximum would prolong the battery life.

Cyclic ageing

Working alongside calendar ageing to wear out your EV battery is cyclic ageing, which is the story of how we use and recharge our electric cars. Although EV batteries were designed to last longer compared to other electronic devices like smartphones, some charging habits we’re accustomed to can decrease their lifespan.

1. The effects of rapid charger:

The impacts of fast charging can be likened to sprinting instead of taking a steady jog - it gets the job done quicker, but it’s a lot harder on the battery. When we opt for fast charging, the battery heats up rapidly. And just as consistent high stress can wear us down, repeated fast charging can wear your EV’s battery down more rapidly, leading to faster degradation.

2. The effects of charging to full:

Additionally, charging your electric car’s battery to full capacity might feel reassuring, but it’s not always necessary. It’s better to charge to 100% only when you’re planning to use your EV for long distances and occasionally fully discharge to prevent memory generation on the battery. Instead, keeping your battery’s charge between 20% and 80% is a smart way to maintain its health and ensure it lasts as long as possible.


Given the complex nature of lithium-ion batteries used in EVs, questions like “How do you prevent battery degradation?” or “How do you check battery degradation?” emerge. Here are some key recommendations:
  • Practice charging your EV to 100% only when necessary, and try to keep it between 80% and 20% in ordinary use.
  • Whenever possible, park in shaded or cool areas, especially during hot days.
  • When going away for prolonged periods of time, try to leave your vehicle at 30% charge to reduce calendar ageing.
  • Embrace smart charging strategies by scheduling charge times.
  • Just as regular health check-ups can help us stay in good shape, our EV Battery Health Checker can be an indispensable tool for your battery condition without the need for any extra hardware. With its ability to deliver an accurate assessment of your battery’s range and performance, making informed decisions about your EV’s maintenance and usage has never been easier.
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