Linear progress: The journey towards efficient EV charging

By Claudio Vittori , Electrification Principal Research Analyst, and Matthew Beecham , AutoTechInsight Research Manager, S&P Global Mobility

As the world races toward electrified transport, electric vehicle (EV) charging speed has become a key concern for consumers, automakers and infrastructure providers.  

But despite headlines touting rapid EV charging and cutting-edge technologies, the reality is more complicated.  

Charging linearity: A key performance metric

Many factors influence EV charging speed, including battery chemistry, thermal management, battery management systems (BMS), charging infrastructure and changing industry standards.  S&P Global Mobility’s latest E-Mobility Technology Module accounts for these variables to forecast real-world range and performance.

A key factor is charging linearity—an EV’s ability to draw power consistently from a charging source. Ideally, charging remains steady, giving drivers a predictable timeline to reach a desired state of charge. In practice, however, charging rates fluctuate based on the battery’s current state of charge, temperature and the charging infrastructure’s characteristics, complicating the process and impacting user experience.

Charging occurs in three phases: constant current (CC), constant voltage (CV) and tapering:

• During the CC phase, the BMS allows high current flow until the battery reaches a set voltage.
• In the CV phase, the current decreases as the battery nears full charge, which can create inconsistencies in charging speed.
• The tapering phase can lead to variability in charging speeds, particularly as the battery nears its maximum capacity. The Tesla Model 3, for instance, maintains a steady charging curve, while the Nissan Leaf tapers off, leaving users guessing about charging times.

To better understand EV charging, we analyzed current models, examining charging curves, battery capacities and BMS capabilities. Chart 1 compares eight EV models, showing which maintain more linear charging profiles. 

Charging linearity for eight EV models (Chart 1)

Advances in technology

Manufacturers are boosting EV charging consistency with innovations like solid-state batteries, which promise faster, more efficient charging. Future BMS will use advanced algorithms for real-time adjustments, while smart charging stations will improve communication between vehicles and chargers. Breakthroughs in thermal management will help maintain safe battery temperatures, ensuring reliable charging.  

The automotive industry trend toward greater linearity is clear, paving the way for a more predictable charging for all drivers. The module provides analytics on charging linearity, helping original equipment manufacturers (OEMs) identify technologies that deliver a more consistent experience.  

Charging infrastructure

Charging infrastructure is critical to the EV user experience, especially as DC fast-charging stations expand, allowing users to reach 80% charge in 20–40 minutes. While Level 1 and Level 2 charging options remain available, the growth of DC fast charging enhances convenience.

As of 2023, there are more than 2.2 million public charging stations worldwide, though home charging remains the most common, particularly in areas with high home ownership. A robust public network of DC fast chargers is essential to ensure equitable access in urban settings.

Smart charging and V2G integration

Smart charging solutions enable real-time communication between vehicles and charging stations, allowing quick adjustments based on grid demand and energy prices. Vehicle-to-Grid (V2G) technology takes this further, letting EVs return energy to the grid during peak demand, stabilizing the grid while putting money back in owners’ pockets.  

Battery swapping 

Battery swapping stations are emerging in urban areas, allowing users to trade depleted batteries for fully charged ones, significantly reducing downtime. Integrating renewable energy into charging stations further boosts sustainability. Central to these advancements is the BMS, which fine-tunes charging rates and prevents overcharging and overheating.  

The module’s automotive forecast and analysis projects charging rates across various conditions, helping OEMs optimize charging systems for predictable performance.

Thermal management strategies

Effective thermal management keeps lithium-ion batteries within their optimal 20–40°C range. High charging rates generate heat, risking thermal runaway, which can cause fires or explosions. In contrast, cold temperatures slow chemical reactions, reducing efficiency.

High-power DC fast chargers also integrate advanced thermal management to maintain safe operating temperatures during rapid charging sessions, helping batteries last longer while improving performance.

The future of EV charging

Charging infrastructure is becoming smarter by the day. Real-time data, dynamic pricing and grid-responsive features allow smart charging systems to optimize charging times based on grid demand, electricity prices and renewable energy availability — boosting grid stability and reducing costs.

V2G technology transforms EVs into distributed energy storage units, supporting the grid during peak demand or outages. Moreover, artificial intelligence analyzes traffic patterns and regional EV adoption to identify the best spots for charging stations and anticipate when maintenance is needed.

Projected charging rates

Chart 2 shows our projected charging rates for five Tesla vehicles, including a 2033 Cybertruck. As manufacturers adopt the advancements mentioned previously, we project a reduction in charging speed variability, leading to a more consistent and user-friendly charging experience. The module’s comprehensive data helps manufacturers understand current charging technologies and develop systems that deliver reliable, predictable charging.

Projected charging curves for Tesla EVs (Chart 2)

Unlocking the full potential of electric mobility

The push for consistent, linear charging is gaining momentum. By understanding factors that influence charging rates and leveraging existing data, EV charging can become more predictable and efficient. Advanced analytics and visualization tools in the module help OEMs evaluate the latest technologies and make informed decisions to improve charging consistency.

As technology evolves, the EV charging landscape is poised for dramatic change, paving the way for wider EV adoption and a more sustainable future. Efforts now extend beyond charging speed to include smart, safe and equitable solutions that work across different regions. Stakeholders must embrace comprehensive strategies that balance speed, efficiency, safety and sustainability to unlock the full potential of electric mobility.

Stay ahead in the journey towards efficient EV charging

To make sense of the evolving charging experience landscape, dive into the E-Mobility Technology Module from S&P Global Mobility. Here, you'll find the latest insights and tools designed specifically for the future of electric mobility, equipping you to stay ahead in this dynamic market.

Explore E-Mobility Technology Module