Smaller batteries mean cheaper and cleaner EVs, and no range anxiety for most drivers

It turns out that bigger is not necessarily better when it comes to battery size and dealing with range anxiety for the owners of  electric vehicles.

Range anxiety remains one of the biggest barriers to the uptake of electric vehicles, with a study published at the end of 2023 by Australia’s Evie Networks and a study by BMW Group published earlier in the year which both found that range anxiety, along with price, were two of the leading concerns.

The International Council for Clean Transportation says the median driving range of EV passenger cars in Europe is 419km, a 10% increase over the previous two years. But it notes that nearly 60% of Europeans say they would require a minimum driving range of 500km before they would consider for purchasing a battery powered EV.

But the ICCT is challenging the notion that bigger batteries are the best solution to range anxiety. They may add more range to the vehicle, but bigger batteries actually increase energy consumption, result in higher costs for purchase and operating expenses, and more greenhouse emissions.

To demonstrate the benefits of smaller batteries with more frequent fast charging during longer-distance trips, the ICCT simulated driving profiles for three generic user types over the course of one year – an urban commuter, a rural commuter, and a frequent long-distance driver.

The ICCT simulation modelled the compact Volkswagen ID.3 (pictured above) over a period of one calendar year with four different battery sizes (28, 58, 87, and 116 kWh) as driven by these three generic driver profiles to determine the most effective combination of battery size and charging behaviour.

The ICCT’s analysis took into account the effect of the battery capacity on vehicle mass, the type of charging used, and the energy consumption of the thermal management system for the cabin and battery, while driving in the annual ambient temperature variability of Berlin, Germany.

While a larger battery size may provide greater peace of mind for those concerned with what they understand to be range anxiety, therefore reducing the number of charging stops, the ICCT’s simulation demonstrated that a larger battery size increases the energy consumption for all users.

Only regular long-distance drivers benefited from a notable decrease in charging stops along their regular route.

“Using a 116-kWh battery instead of a 28-kWh battery increases energy consumption between 13.4% and 16.9% for the three driver types” the report finds.

“For long-distance drivers, en-route charging stops per year decrease by 260. However, urban and rural commuters will only save 35 additional stops because the range of the smaller battery capacity covers most of their trips.”

Similarly, doubling the EV driving range from 250km to 500km raises the total cost of ownership by anywhere from 15% to 23% – a figure which is more pronounced for rural and urban driver types, with 20% and 23% higher costs, respectively.

Conversely, “the lower energy consumption and purchase price of a vehicle with a smaller battery results in substantially lower expenses despite the higher electricity cost associated with more frequent fast charging.”

Finally, the report demonstrates that using a smaller battery and reducing electric energy consumption contributes to lower vehicle life-cycle greenhouse gas emissions for all users.

In relative terms, the ICCT study found that urban commuter experiences the biggest increase in emissions when doubling the battery size (20%) due to the more frequent and shorter trips of this user type, “which requires more frequent cooling or heating of the cabin and battery and thereby increases the energy consumption of the thermal management system.”

The ICCT’s study concluded that, for most of the year, a larger battery does not affect the number of charging stops en route for the urban and rural driver types, given that long-distance trips represent less than 2% of those taken during a year.

Double the range from 250km to 500km will therefore not decrease the number of days where en route charging is required but does reduce the number of charging stops per long-distance trip to only two.

On the flip side, however, the long-distance driver simulated in the study does benefit from a longer range with one charging stop less per commute day, but at the expensive of 15% higher costs.

“Due to the frequent long-distance trips, the long-distance driver benefits most from a vehicle with a 500-km range compared to a vehicle with a 250-km range,” the authors concluded.

“However, for the urban and rural commuter user types, the larger battery comes at a considerably higher cost than a smaller battery combined with fast charging.”