Your Questions Answered: Insights into Battery Degradation
With the increasing popularity of EVs, it is vital for both current owners and potential buyers to understand battery degradation. This article will explore the lifespan of EV batteries, the factors influencing their durability, and how various vehicle makes and models compare regarding battery health over time.
How Long Can You Expect EV Batteries to Last?
According to research from Geotab, EV batteries generally demonstrate impressive longevity. On average, these batteries degrade at a rate of around 1-2% per year. This suggests that the majority of EV batteries are likely to last throughout the vehicle's usable life without the need for replacement.
While it is true that EV batteries will ultimately wear down, this usually occurs long after the vehicle itself is no longer in service. For example, if you buy an EV with a range of 150 miles, you might see a reduction of approximately 17 miles in range after five years. Although this loss might not significantly affect daily driving, it is an important consideration for fleet managers looking to maximise the efficiency of their investments.
Key Factors Affecting Battery Lifespan
Several important elements can influence how long lithium-ion batteries in battery electric vehicles (BEVs) and plug-in hybrid electric vehicles (PHEVs) remain effective:
- Age: Battery performance typically declines as they age.
- Temperature: Extreme heat or cold can hasten the degradation process.
- State of Charge: The charge level can significantly impact battery health.
- Charging Method: AC versus DC charging can lead to different outcomes for battery longevity.
- Usage Patterns: How often and in what conditions the battery is operated matters.
- Vehicle Make and Model: Different manufacturers may have varying levels of battery technology.
Examining Battery Degradation Across Different Vehicles
An in-depth analysis of 6,300 electric vehicles by Geotab reveals that battery performance varies across different models and makes. This variation is largely determined by factors such as the chemical composition of the battery and the effectiveness of its thermal management system.
The Impact of Cooling Systems: Liquid vs. Air
For instance, the 2015 Tesla Model S, which employs a liquid cooling system, has an average degradation rate of 2.3%. In contrast, the 2015 Nissan Leaf, which uses passive air cooling, shows a higher degradation rate of 4.2%. This comparison highlights how superior thermal management can play a crucial role in maintaining battery health.
Understanding State of Health (SOH)
Battery degradation is a natural phenomenon that results in a decrease in the amount of energy a battery can store. The condition of a battery is often referred to as its State of Health (SOH), which starts at 100% and diminishes over time. For example, a 60 kWh battery with a SOH of 90% would function similarly to a 54 kWh battery.
To help ensure longevity, manufacturers often implement mechanisms that limit the maximum and minimum charge levels, protecting the battery's overall health. Many vehicles also allow users to set their own maximum charge limits.
Usage and Environmental Factors
Interestingly, our data indicates that EVs that are used frequently do not necessarily experience higher levels of battery degradation. This finding is encouraging for fleet operators, as it means they can confidently deploy their EVs without significant concerns about battery life.
However, temperature is a key factor. EVs operating in hotter climates tend to degrade more quickly than those in more temperate regions. For example, vehicles in areas with many days exceeding 27°C may face a heightened rate of battery decline.
Charging Types
The method of charging can also impact battery health. Charging stations are typically divided into three categories:
Here’s the simplified breakdown
- AC Charging
- Slow: 3 kW, 6-12 hours.
- Fast: 7 kW, 4-6 hours; 22 kW, 1-2 hours.
- DC Charging
- 50 kW: 20-60 mins.
- 100 kW: 20-30 mins.
- 150 kW: 20-30 mins.
- 200 kW: 20 mins.
- 250 kW: 15-20 mins.
- Summary
- AC: Slow, for home.
- DC: Fast, for quick stops.
Conclusion
In summary, while some battery degradation in EVs is unavoidable, various factors influence the lifespan of these batteries. On average, EV batteries are expected to endure longer than the vehicle itself, especially when good charging practices are followed. The combination of reliable warranties and decreasing battery prices should encourage potential buyers to consider EVs with confidence.
For those interested in ensuring the longevity and health of their EV batteries, battery testing options are available through Altelium. To discuss battery testing further, please reach out to Alex Johns at alex.johns@altelium.com.
Understanding battery health is crucial for making informed decisions about electric vehicles.
