In 2022, global Electric Vehicle (EV) sales exceeded 10 million units, marking a threefold surge in sales over three years, from 4% in 2019 to 14% in 2022. The United States reached a significant milestone in 2023, with 1.19 million EVs sold domestically.
While soaring sales are encouraging for EV car makers, potential new EV buyers may be deterred by concerns about lower temperatures impacting performance of EV batteries. Cold weather diminishes the range (distance an EV can travel on a single charge) of EV batteries.
EV manufacturers must confront these technical challenges to ensure that EVs can be a reliable and efficient transportation option regardless of weather conditions.
How does cold weather affect batteries?
EVs can lose anywhere from 10% to 40% of their range in frigid temperatures, and charging can take longer in extreme cold. These declines can be due to the following factors:
- Cold temperatures and slower battery reactions: When it is cold, the movement of lithium ions slows down. This results in decreased energy release and reduced efficiency in generating electricity. Consequently, this leads to a notable decline in the overall performance of the EV’s battery technology.
- Energy consumption of EV climate control systems: Cabin heating that ensures passenger comfort relies on heaters that draw power from the high-voltage battery. Climate control diminishes the available energy capacity for driving.
Range loss in EVs: Model-dependent but persistent
According to AAA’s testing in -6.7° C (20°F) weather, temperature alone could reduce range by 10-12%. However, the utilization of in-vehicle climate control could exacerbate the loss of power, potentially reaching up to 40%.
Source: Recurrent
As seen in the image above, a recent comparative analysis by Recurrent of 12 popular EV models (Winter 2022/2023) reveals some differences in winter range loss compared to optimal conditions (Analysis based on 10,000+ vehicles). Although the message indicates that some models might be better than others in addressing power loss, EV owners still face the same power loss challenge.
Addressing EV battery challenges in cold weather:
As we look into the challenges that cold weather presents to Electric Vehicle (EV) battery performance, it’s imperative to consider the words of Dr. Sofiane Boukhalfa, Technical Director at PreScouter: “As electric vehicle sales surge globally, executives at automotive F500 companies must heed the call to tackle cold weather challenges head-on. By investing in R&D partnerships and innovative solutions, they can lead the charge towards reliable and efficient EVs in any weather condition, securing a competitive edge in the evolving automotive landscape.”
Without further ado, let’s explore the recent developments aimed at addressing these challenges.
Finding the optimal electrolyte 
A recent breakthrough designed soft solvating electrolytes capable of enhancing the performance of a 4.5V NMC811||graphite battery cell.
Tests showed that:
- coin cells (areal capacity >2.5 mAh/cm²) retained 75% of their capacity at room temperature when charged/discharged at -50 °C.
- practical pouch cells can maintain > 83% of their capacity after being charged and discharged 300 times at very cold temperatures (-30 °C).
- battery cells showed an average charging efficiency of more than 99.9%.
This discovery opens up possibilities for making more powerful batteries that charge faster, and work in extreme conditions.
Improving fast-charging batteries in any weather condition
Researchers at Penn State University have developed a method that uses a controllable cell structure to improve low-temperature fast charging capability without sacrificing battery cell durability.
The Lithium Plating-Free (LPF) fast charging at 9.5 Ah 170 Wh/kg can achieve an 80% state of charge in 15 minutes under any temperature condition, including extreme cold (-50°C). Moreover, batteries can maintain exceptional cycle longevity (4,500 cycles, equivalent to >12 years and more than 280,000 miles of electric vehicle lifespan).
Harnessing electric current pulses from the car’s motor
In cold temperatures, heating EV batteries can involve polarizing the battery cells using pulse currents. A recent study proposed an adapted EV circuitry that remains compatible with existing setups. Moreover, the method optimizes operational conditions to facilitate fast battery heating.
The modified circuit allows electricity transfer between cells through a motor, resulting in significantly higher battery currents than conventional circuits. From 1.41C to 4C (C represents the magnitude of the pulse current in terms of the cell’s capacity), which leads to a rapid rise in battery temperature of 8.6°C/min in cold conditions.
This heating technique offers low cost, high efficiency, and negligible impact on battery degradation (0.5% after 5,000 cycles). This makes it a practical and promising solution for heating EV batteries.
Utilizing microwave energy
University of Birmingham researchers are developing an innovative energy storage system, the e-Thermal bank. The system combines a chemical heat pump with microwave energy to provide heating or cooling as an additional energy source for EVs.
The e-Thermal bank could be charged at EV charging stations using microwave energy to separate a solid-vapor working pair and convert the vapor into liquid. The charging process stores microwave energy inside the car.
During discharge, the stored energy generates heat through an exothermic reaction and cooling through a liquid-gas phase change process. The e-Thermal bank aims to alleviate thermal management tasks and can potentially extend the driving range by up to 70%.
Improving battery thermal management systems (BTMS)
The BTMS regulates the temperature of the EV battery pack, ensuring it operates within an optimal temperature range. Some solutions for dealing with frigid temperatures include the use of heat pipes and cooling liquids which have the potential to conserve energy in electric vehicles.
Incorporating heaters directly into batteries can help manage the temperature in EVs and therefore maintain optimal battery function. These heaters are integrated into the BTMS and are part of new designs for battery setups in vehicles.
Two companies, Caliente LLC and SINOMAS, offer innovative solutions for heating EV batteries:
Caliente LLC provides ModuleDirect Heater Pads and PTC Fluid Heaters designed to ensure faster heating, uniformity, and can serve as a discharge resistor as necessary.
SINOMAS offers flexible heating elements that can be tailored to fit between battery cells, wrap around them, or adhere to cold plates beneath modules. These heaters distribute heat evenly, shorten heating time, and enhance energy efficiency for EVs during winter.
These heating solutions are critical for improving battery efficiency, extending battery lifespan, reducing charging duration, and ensuring consistent performance in cold climates. By preheating batteries before rapid charging in cold weather, these systems help maintain ideal battery temperature for enhanced EV operation.
Designing 3D electrode structures
Three-dimensional electrode architectures enable faster ion movement, especially crucial for lithium-based batteries which solve problems such as reduced charge-transfer efficiency and lithium-ion desolvation issues.
Benefits of using 3D electrode architectures
- Increased surface area: A larger surface area for electrochemical reactions can boost the overall battery capacity and performance.
- Enhanced ion transport: 3D structures can facilitate faster ion movement, vital for maintaining battery performance in cold conditions.
- Improved power and energy density: 3D architectures separate power and energy density, allowing for batteries with high energy capacity and rapid charging or discharging rates.
Advantages of 3D electrodes in cold weather conditions
- Improved heat dissipation: The enhanced heat transfer and dissipation of 3D electrodes help prevent cold-induced performance degradation by ensuring uniform temperature distribution and minimizing the risk of freezing.
- Better thermal uniformity: The ability of 3D electrodes to disperse heat evenly helps counteract the uneven performance and potential damage to the battery. This ensures a consistent performance, even in cold conditions.
- Enhanced mechanical stability: The more robust structural stability of 3D electrodes helps to withstand mechanical stress on battery components. This reduces the risk of damage and maintains reliable operation in low temperatures.
- Reduction in dendrite formation: 3D electrode structures enhance safety and reliability by minimizing dendrite formation.
- Handling of shrinking and expansion: Cold temperatures can exacerbate the expansion and contraction of battery materials during charge and discharge cycles. 3D electrode materials allow them to accommodate these temperature-induced changes, extending battery lifespan even in low-temperature conditions.
Advances by Addionics and Enovix
Addionics has developed smart 3D electrodes aimed at enhancing rechargeable battery performance. While current battery collectors typically utilize 2D metal foils, which have remained unchanged for decades, Addionics has redesigned battery architecture aiming to achieve higher capacity, improved safety, reduced charging time and cost, and longer lifespan of EV batteries.
Enovix has devised a 3D cell structure and high-capacity silicon anode. This architecture allows for a fully active silicon anode, resulting in a battery with superior energy density, extended cycle life, and rapid charging capabilities while maintaining safety standards.
Who’s racing to fix the problem?
Geographies with harsh winter climates, such as the northern regions of North America, Europe, and Asia, regularly experience below-freezing temperatures. Extreme cold weather often spans across a significant portion of the year (~100 days annually). At the same time, countries within these regions are among the highest in EV sales. For EV sales to remain strong, EV manufacturers need to find a solution. Here’s what some industry players are working on.
Tesla
Tesla has developed an innovative heat pump, featuring advancements like the “super manifold” and “octo-valve.” The design enhances efficiency and adaptability, particularly in extreme cold conditions. This system can generate its own heat to maintain cabin warmth and prioritize power when necessary.
Tesla combined two valves into one and utilized the super manifold (two layer PCB assembly that manages the flow of coolant in the vehicle), significantly reducing the number of components. This approach enhances reliability by minimizing potential points of failure.
Greater Bay Technology
Greater Bay Technology (GBT) has created an innovative EV battery, the Phoenix cell. It charges from 0 to 80% in 6 minutes and is claimed to work under extreme temperatures, heating up quickly from -4°F to 32°F. With a high-energy density of 260 Wh/kg, it can power a car for over 620 miles and lasts for ten years or 497,000 miles.
GBT plans to build a factory in Guangzhou, China, to make enough batteries for around 120,000 vehicles. The company is partnering with GAC to put the Phoenix cell in their electric cars, which could make EVs more popular with faster charging and reliable performance in any weather.
Amprius Technologies
Amprius Technologies has developed innovative lithium-ion battery technology using silicon anode technology, which offers remarkable improvements in energy density and performance (a 100% silicon anode has ~10X capacity compared to graphite). Their latest lithium-ion cell has an energy density of up to 500 Wh/kg and 1,300 Wh/L. This provides extended run time and potential industry-changing performance. These batteries can charge up to 80% in under 6 minutes and operate effectively in a wide temperature range from -30°C to 55°C.
Valeo
Valeo’s Smart Heat Pump technology improves energy efficiency for EV batteries, particularly in cold weather. The solution helps preserve battery life and can extend an electric vehicle’s range by up to 30% in winter. The system efficiently utilizes ambient energy to heat, cool, and demist car cabins.
Lexus
The Lexus RZ 450e incorporates a radiant heating system inspired by household heating systems. The radiant heating directly warms objects rather than the surrounding air, which makes it highly efficient and consumes less energy.
In the RZ 450e electric crossover, Lexus utilizes this technology in the higher trims to warm the front occupants. Two panels positioned under the dashboard emit infrared radiation, effectively heating solid objects in their line of sight. These panels are designed to automatically reduce surface temperature if touched, ensuring passenger comfort and safety. The process consumes 8% less energy, reducing workload and extending the vehicle’s range.
As these companies push the boundaries of what’s possible, they are not just enhancing the appeal of electric vehicles in colder geographies; they’re also setting new standards for the automotive industry at large. This effort is critical for EV adoption at a global scale, as noted by Dr. Sofiane Boukhalfa, Technical Director at PreScouter: “In the race towards sustainable mobility, executives in automotive F500 companies must prioritize innovation in battery technology and thermal management systems to ensure optimal performance, especially in cold climates, thereby bolstering consumer confidence and driving global EV adoption.”
What’s next?
Manufacturers can invest in R&D to discover innovative solutions. Some options include forming alliances with top academic institutions who are already focused on enhancing battery endurance at low temperatures. This may result in a more cost-effective research yielding viable solutions, and offering original designs with higher ROI.
Progress in battery technology and thermal management systems presents promising avenues for overcoming cold weather challenges and expediting sustainable mobility. EV manufacturers should signal customers their ongoing pursuit of maintaining optimal battery performance regardless of weather conditions. This will enhance consumer confidence and promote the global adoption of electric vehicles.
