Speeding up EV adoption through smaller batteries with extreme-fast charge capability

Blog Post
Dr. Dani Aronov, CTO

Even as electric vehicles (EVs) continue to grow their share of the passenger vehicle market, the "early majority" phase of adoption still eludes the industry.

To date, EV owners have largely been drawn from the ranks of affluent, environmentally-conscious consumers, not the typical car buyer who is primarily looking for cost-effective, convenient transportation. Persuading lower-income, single-vehicle households to opt for a more expensive EV, reliant on a limited charging infrastructure is proving difficult.

To attract these consumers and speedup EV adoption, manufacturers have invested a great deal of time and resources to address the most pressing challenges facing the mass rollout of electrified vehicles. Thus, largely through advances in technology, EVs are safer, charge faster, cost relatively less, and travel much further than they did in the early days of electrification.

For instance: 15 years ago, EV pioneers had real range limitations. The first Nissan Leaf offered a battery range of about 100 miles, while the original Smart ForTwo Electric Drive struggled to see even 50 miles on a charge in real-world driving. It was from here that the phrase ‘range anxiety’ evolved as one of the key reasons restricting the mass rollout of electrification.

But, thanks to the latest generation of EVs such as the Lucid Air - that returns over 500 miles - and the Ioniq 6 with its EPA estimated range of 361 miles, range anxiety is gradually becoming less of a concern.

However, this improvement in range has come at a cost. Despite the significant advances in technology – particularly battery chemistry and design – EV manufacturers have mostly gone down the road of fitting larger Li-ion batteries (LiBs) with increased capacity to extend the EV’s range.

Between 2015 and 2020, the average pack capacity for BEV cars increased from 24.2 to 43.9 kWh in China, from 30.1 kWh to 54.6 in Europe, and from 41.2 to 70.5 kWh in the US. In the US where the market demands longer-range vehicles, average battery capacity has been 43 percent higher than that of Europe and 71 percent higher than in China where electric vehicles are mostly used within cities and therefore require less range.

Batteries keep getting larger | Image Source: IDTechX

However, even though large, higher-capacity LiBs have proven a quick-fix to addressing range anxiety the trend has brought with it many unintended negative consequences.

Large Li-ion battery packs exacerbate many consumer concerns regarding EV ownership

While the “just add more battery” approach has certainly played a positive role in alleviating consumers’ anxieties around range, the larger and heavier battery packs aggravate many of the other concerns and challenges EVs need to overcome to achieve mass adoption.

  • High cost for the EV owner: With the high initial purchase price top of the list of barriers to widespread EV adoption, fitting larger batteries hampers meaningful cost-reduction. Typically, Li-ion battery packs account for between 30 and 45 percent of the total vehicle cost. So with a cost of about USD153/ kWh a 2019 Tesla Model S standard range AWD 75 kWh battery pack, at USD11,475, would cost USD3,825 less than the Long Range version. Smaller, cheaper battery packs are particularly important to the survival of the cost sensitive small-car sector.
  • High cost for the car maker: Larger batteries also incur higher warranty expenses for the OEM as well as greater freight and recycling costs.
  • Lack of accessibility of fast charging models: Although premium cars with larger packs are mostly capable of fast charging, smaller models do not have this ability. Fast charging capability is largely available in premium cars (with larger packs).
  • Weight impedes energy efficiency: What is more the full weight of the battery that, unlike an ICE’s fuel tank that is proportional to the fuel level, is omnipresent. Thus, with 4 lbs. of battery mass consuming approximately 1 mile of EV range the heavier Long Range Model S, at 25 kWh/100 miles, is also less energy efficient than the 28 kWh/100 miles achieved by the Standard version.
  • Better weight distribution: At the same time, with weight distribution playing a significant role in the dynamic balance of the EV, the placement of the battery pack is critical to the vehicle's handling. Thus, with a smaller battery easier to position in the vehicle’s structure than a large higher capacity unit, handling is simpler to optimize.
  • Lighter EVs handle better: The additional mass of the larger battery carries over to the dynamic performance of the vehicle. As a result of the increased inertia, the vehicle is not as responsive when changing direction and requires higher performance brake and suspension systems to meet the requirements of the heavier vehicle. The same applies to tires, where, largely due to the weight, EV tires wear 30 percent faster.
  • Safety and thermal management concerns: Researchers at the Insurance Institute for Highway Safety (IIHS) have also voiced concern about the safety implications linked to the increased weight of EVs. According to Raul Arbelaez, vice president of the vehicle research center at IIHS this extra weight poses a danger to other vehicles on the road as well as vulnerable road users like pedestrians and cyclists.

What is more, larger batteries containing more energy require more substantive safety structures and systems. This includes additional impact protection to ensure the safety of the vehicle’s occupants in the event of an accident, as well as more complex thermal management to prevent potential thermal events, aggravated by the increased energy of the higher capacity packs.

Larger Li-ion batteries require robust safety structures | Image source: SSAB

The physical size of these large batteries also dictates the placement of the battery pack, which in turn often impacts the cabin space available for the occupants and their luggage.

  • Long charging times: What is more, even though larger battery packs have made a significant contribution to extending the EV’s range, due to their higher capacity they also take longer to charge.

So, while a AAA survey of EV drivers showed that 77 percent of respondents were less or no longer concerned about range post-purchase, a similar survey conducted in 2023 by the Canadian Automobile Association found that 44 percent of EV owners had the availability of public charging as their top concern. Significantly, these EV owners spent 30 percent of their time charging outside the home, often using fast chargers.

This is a strong indication, that, after more than a decade of exposure to electric vehicles the market is beginning to accept the paradigm shift these vehicles bring to the user experience. This offers manufacturers a window of opportunity to significantly address the remaining consumer concerns obstructing an even quicker uptake of the nascent technology.

Smaller fast-charging batteries, such as StoreDot’s XFC EV battery, are designed to ease EV-buyers’ remaining concerns about going all-electric, thereby speeding up the rollout of clean transportation that will significantly reduce global GHG emissions.

Smaller StoreDot extreme fast charging Silicon batteries are ready to overcome the remaining barriers to mass EV rollout

With the average driver in the US covering less than 50 miles a day an EV with a range of about 143 miles would satisfy most driving needs if supported by fast reliable charging and the necessary infrastructure.

StoreDot’s Extreme Fast Charging (XFC) silicon battery technology capable of charging a LiB to 80 percent in under 10 minutes, and add 100 miles, or 160 km of range in 5 minutes - irrespective of the State of Charge (SoC) of the battery – is a production-ready solution capable of addressing the key remaining concerns potential EV owners may have.

With a growing number of drivers experiencing EV ownership “first-hand,” range-anxiety has largely been relegated to the archives, and by adopting extreme-fast-charging technologies manufacturers can fit cheaper and lighter batteries with the same operational throughput for the vehicle’s lifetime. A shift in focus, from extending range through larger batteries, to radically reducing charging times, offers manufacturers the opportunity to reevaluate their approach to EV development to broaden the owner base.

StoreDot’s XFC technology allows manufacturers to downsize the battery pack | Image Source: StoreDot

Of course, research into increasing energy density in LiBs that could also enable downsized batteries continues, but at a price point that serial production EVs are unlikely to support. However, the improvements brought about by XFC could transform the accessibility of EVs, while better car efficiency, reduced raw material usage, and less recycling at the end of the battery’s in-vehicle life, will boost battery sustainability. XFC in smaller packs also improves the efficiency of regenerative braking by accommodating the high peak currents produced during energy recuperation.

The smaller pack-size also reduces the amount of energy that needs to be controlled in the event of an accident, making the lower capacity battery inherently safer.

Furthermore, unlike many current EV LiBs, StoreDot’s XFC silicon battery is capable of regular extreme fast charging without compromising cyclability or battery life. The XFC battery has achieved over 1250 continuous and consecutive extreme fast-charging cycles at a charge rate more than three times higher than most current LiBs before reaching SoH of 80 percent.

So with range anxiety no longer a significant stumbling block to the rollout of EVs, manufacturers are at a tipping point in the history of electrification. By choosing smaller extreme fast charging batteries the industry can reduce costs, improve safety, and eliminate charge anxiety – all of which are required to stimulate widespread adoption of all-electric transportation.