The effects of heat on battery performance and durability
Accelerated deterioration and reduced capacity
High summer temperatures pose a significant risk to the longevity and efficiency of electric batteries, particularly those used in electric vehicles. Prolonged exposure to heat can accelerate the degradation of essential battery components, such as electrodes and electrolytesresulting in a reduction in energy storage capacity.
What are the impacts on chemical reactions?
At high temperatures, chemical reactions inside battery cells occur more rapidly. This acceleration can be particularly damaging to electrodes, where increased chemical activity can lead to premature degradation. Exposure to temperatures above 30°C can shorten the life of a lithium-ion battery, sometimes by more than 20% compared with normal conditions.
Electrolytes, which facilitate the flow of ions between electrodes, are also vulnerable. High temperatures can cause solvents in electrolytes to evaporate, reducing their efficiency and increasing the risk of internal short-circuiting. Heat can induce microscopic cracks and swelling in electrode materials, compromising the battery's structural integrity.
Understanding the effects of heat on battery components is therefore essential for professionals, and adopting appropriate thermal management strategies and recharging practices is crucial to minimizing these negative impacts and ensuring optimum electric battery life.
The challenges of high-temperature recharging
Charging electric vehicles (EVs) during periods of intense heat raises several issues impacting both battery performance and longevity:
- Increased thermal stress during recharging: in hot weather, this can push the battery's internal temperature beyond safe thresholds, risking thermal runaway.
- Accelerated degradation, reducing its capacity to store energy.
What are our recommendations?
We recommend recharging electric cars during the cooler periods of the day to avoid exposing the battery to extreme temperatures.
In addition, it can be a good idea to use advanced thermal management systems. Indeed, some models incorporate liquid cooling systems that help regulate battery temperature during recharging, keeping it within an optimal range.
By integrating these practices and technologies, professionals can extend the life of their electric vehicle batteries and guarantee constant performance, even in difficult climatic conditions.
Also read → Preconditioning an electric car battery
Battery thermal management systems (BTMS)
Battery Thermal Management Systems play a crucial role in preserving the longevity and efficiency of electric vehicle batteries, especially under extreme climatic conditions. These systems are designed to keep batteries within an optimum temperature range, minimizing the risk of premature degradation and thermal runaway.
How do they work?
BTMS regulate battery temperatures using a variety of cooling and heating methods, including liquid cooling, air cooling and, in some cases, electric heating systems for cold climates. For example, liquid cooling, which is often used in high-end vehicles such as the Teslauses a fluid to absorb heat from the battery cells and dissipate it outside the vehicle. This method is renowned for its ability to evenly maintain battery cell temperatures, even during rapid charging or high outside temperatures.
What are the advantages?
Vehicles equipped with advanced thermal management systems have shown a significant reduction in capacity losses and an increase in battery life. For example, liquid cooling systems can reduce battery temperature peaks by up to 15°C, which is essential during rapid charging or operation in hot environments.
The electric city cars like the Fiat 500e or the Renault Twingo e-Tech use an air-cooling system, which is simpler and less expensive than liquid cooling, but can be less effective in extremely hot climates. On the other hand, more sophisticated systems such as those used by Tesla enable more precise temperature regulation, resulting in better overall performance and greater range.
BTMS are therefore not only essential for performance and safety, but also play a key role in vehicle energy efficiency. By maintaining batteries at their optimum temperature, BTMS enable vehicles to operate more efficiently, reducing energy consumption and increasing the distance vehicles can travel per charge.
What professionals recommend
For professionals operating or managing electric vehicles, adopting effective heat management practices is essential to optimize performance and extend battery life. Here are some strategic tips based on studies and recommendations from experts in the field.
Park in the shade
Parking in the shade or in covered environments can significantly reduce the internal temperature of a vehicle, and consequently of the battery. According to a study by the National Renewable Energy LaboratoryAccording to a study by the National Renewable Energy Laboratory, parking in the shade can reduce a vehicle's internal temperature by up to 6°C compared with parking in direct sunlight. This simple measure can reduce the need for intense cooling when starting the vehicle, thus reducing the load on the battery.
Precondition the battery before setting off
Preconditioning your electric car's battery before starting a journey, especially on hot days, can improve its efficiency. Preconditioning can be activated via a mobile app or settings on the vehicle's dashboard. This practice allows the battery to start operating in its ideal temperature range, improving fuel efficiency and vehicle performance. Preconditioning can improve battery performance by by 10-15%, depending depending on climatic conditions.
Schedule charging during cooler periods
Charging your electric vehicle during the cooler hours of the day, often early in the morning or late at night, can reduce the risk of overheating and thermal runaway. Lower ambient temperatures during these hours help keep the battery at optimum temperature throughout the charging process. Recharging at night can reduce the average charging temperature of the battery by 5-8°C, which is beneficial to the long-term health of the battery.
Also read → What is the purpose of the heat pump on an electric car?
What are the latest innovations and technological advances?
Improving materials and battery design
Advances in battery materials are at the heart of innovations to improve energy density and battery life, especially in high-temperature conditions.
The importance of nickel in modern batteries
Nickel is used to increase the energy storage capacity of batteries, not only improving energy density, but also extending battery life in hot conditions. High-nickel batteries, such as those using NMC (nickel, manganese, cobalt) chemistry, are particularly effective in maintaining good performance even at high temperatures. Research has shown that NMC batteries can retain higher capacity and offer greater resilience to thermal degradation than less nickel-containing options.
Teslafor example, has opted to use high-nickel cathodes in its Model 3 and Model Yrange, improving both energy density and heat resistance. This approach has led to a significant increase in vehicle range and a reduction in the incidence of battery degradation at high temperatures.
In addition to nickel, other material innovations include the use of advanced materials for electrolytes and separators, which are designed to perform optimally over extended temperature ranges. For example, some research is focusing on the development of solid electrolyte batteries which, in theory, could support better thermal performance and reduce the risk of thermal runaway.
These hardware advances not only improve performance and safety, they also pave the way for battery applications in more demanding environments and support the wider adoption of electric vehicle technology, better meeting the needs of professional users in terms of durability and reliability.
Regenerative braking and its impact
Regenerative braking is a key technology that plays a crucial role in improving energy efficiency and extending battery life, especially in summer driving conditions. This function recovers part of the kinetic energy generated during deceleration and converts it into electrical energy, which is then stored in the vehicle's battery.
How does it work?
When a driver lifts off the gas pedal or presses down on the brake pedal, the regenerative braking system transforms the electric motor into a generator, recovering energy that would otherwise be lost as heat by conventional brakes. This recovered energy is then used to recharge the vehicle's battery.
What is the impact on energy efficiency and battery life?
Regenerative braking significantly improves energy efficiency, particularly in urban environments where frequent stops enable optimum energy recovery. For example, regenerative braking can increase the range of electric vehicles by up to 10-25%, depending on driving conditions and vehicle model. This increase in range is particularly beneficial during the summer months, when increased use of air conditioning can otherwise reduce the vehicle's effective range.
What are the other benefits during the summer?
In summer, the regenerative braking system also helps to reduce the thermal load on the battery. By minimizing the use of conventional brakes, which generate heat, and increasing energy recovery, the system helps keep the battery in a lower, safer temperature range. This is crucial in preventing premature ageing of the battery due to excessive heat, prolonging its useful life and reducing maintenance requirements.
Also read → The 10 innovations that promise to revolutionize electric car technology
Conclusion
Understanding and managing the impact of summer heat on electric vehicle batteries is therefore crucial for professionals. Adopting best practices such as regenerative braking, using advanced thermal management systems, and scheduling recharging during the coolest hours can significantly improve battery durability and efficiency. These measures not only extend the useful life of batteries, but also ensure optimum vehicle performance in demanding climatic conditions, contributing to sustainable, efficient mobility.
