eTrailers, eTrucks and battery swapping
Long-distance transport and electrification: challenges and opportunities presented by battery replacement infrastructure
Introduction:
The need to decarbonize road freight transport
As we all know, road freight transport is facing fundamental change. In view of rising transport volumes – according to the German Federal Ministry of Transport's transport forecast, freight transport volumes will increase by around a third by 2040 – climate targets cannot be achieved without phasing out diesel in the truck sector. The decarbonization of heavy-duty transport has therefore been given top priority. The European Union, for example, stipulates that CO₂ emissions from newly registered heavy-duty trucks must be reduced by 45% by 2030, 65% by 2035, and 90% by 2040 compared to 2019 levels.
Against this backdrop, battery-electric drives are currently considered the most promising solution for zero-emission long-haul transport. Other technologies such as hydrogen fuel cells or overhead line trucks are being investigated, but the battery-electric option offers clear advantages, as outlined below in three key arguments.
Battery-electric trucks as the best solution: Three key arguments
Falling battery costs thanks to new technologies: Modern battery technologies are leading to a dramatic drop in costs. A concrete example is the upcoming transition from lithium-ion to sodium-ion batteries. Sodium is a raw material that is available in almost unlimited quantities and is inexpensive (it can be extracted from table salt, for example), which reduces dependence on scarce resources. Studies estimate a cost advantage of 30–40% over today's lithium-ion batteries. In addition, sodium-ion batteries do not require lithium or cobalt, which alleviates supply chain problems and increases sustainability. This development is likely to significantly reduce the acquisition costs for electric trucks and e-trailers in the coming years.
Increasing battery longevity: New battery generations have a significantly longer service life. Improved cell chemistries (e.g., single-crystal cathodes) and higher-quality materials enable significantly more charging cycles before capacity noticeably declines. Current research shows cell types that complete over 20,000 charging cyclesbefore capacity drops to 80% SOH – compared to approximately 2,400 cycles for conventional cells. Currently, 8,000 full cycles can be guaranteed. This corresponds to a potential mileage of around 4 million kilometers for an e-truck eTrailer combination with a range of 500 km per full cycle. In practice, manufacturers are now also aiming for batteries with a service life of 15 years or over 1.5 million km, which roughly corresponds to customer expectations for diesel vehicles today. This increased longevity is further enhanced by optimized battery control and adapted load profiles. For freight forwarders, this means long-term usability of the batteries over several years, which reduces total operating costs and significantly improves depreciation planning.
Superior efficiency across the entire energy chain: Battery-electric drives use the energy they consume much more efficiently than other technologies. From a well-to-wheel perspective (from power generation to the wheel), e-trucks and eTrailers achieve efficiencies of around 70–75%, while hydrogen fuel cell trucks only achieve around 25–30%. The reason: in electric trucks and eTrailers, the electricity is stored directly in the battery and then used by the electric motor – this process is comparatively low-loss. In contrast, hydrogen first requires generation by electrolysis (with large conversion losses), then transport and storage of the H₂, and finally reconversion into electricity in the fuel cell, which in turn loses about half of the energy. In practical terms, this means that a hydrogen-powered vehicle requires around three times more energy per kilometer than a battery truck with a connected eTrailer to cover the same distance. This efficiency advantage of battery technology is reflected in lower operating costs (energy consumption) and a better carbon footprint.
Limits of battery electrification in long-distance transport
Despite the advantages mentioned above, battery-electric trucks have certain limitations, especially over long distances. The limited gravimetric and volumetric energy density of batteries is one of the biggest challenges. Current lithium-ion batteries store around 150–250 Wh of energy per kilogram of mass – diesel, on the other hand, contains the equivalent of approx. 12,000 Wh/kg. This means that batteries for long ranges are very heavy and bulky. A calculation example: For a range of around 800 km, an electric truck (40 t total weight) requires a battery of ~1,000 to 1,150 kWh. Even at an optimistic 200 Wh/kg, this battery weighs around 2,000 kg per 100 kWh, or a total of approx. 10 tons. If additional reserves are taken into account (oversizing to avoid deep discharges), the battery weight comes to almost 11 tons. By comparison, a hydrogen truck with a range of 800 km requires only about 1.4 tons, including tanks, fuel cell, and buffer battery. In this scenario, battery electrification therefore results in a good 5–6 tons less payload or a correspondingly higher total weight.
Batteries also take up space in terms of volume. Although battery packs for electric trucks can usually be accommodated in the frame and on the vehicle floor, very large battery capacities reach the space limits of the towing vehicle. One solution is to relocate additional battery storage to the trailer (trailer/semi-trailer) or to equip the trailer itself with drive modules. This approach was already demonstrated in 2022 at the same conference as today, and these vehicles are already on public roads. Today, KRONE is building such powertrains into its semi-trailers with Trailer Dynamics, and other trailer manufacturers will follow KRONE's example very soon. Such an eTrailer supports the tractor unit (whether diesel or electric) and provides additional energy. This increases the total range without the tractor unit having to carry the entire battery load on its own. At the same time, the weight is distributed more evenly between the tractor unit and the trailer. However, this outsourcing makes the vehicle technology more complex and will require significantly better integration of the eTrailer into the tractor unit in the future.
Remaining challenges: infrastructure and operating costs
Even if the vehicles are technically suitable, a number of practical challenges still need to be overcome before battery-electric long-haul trucks can be used across the board. The most important points are:
Lack of availability of a powerful charging infrastructure: There are currently far too few public fast charging points for heavy trucks and eTrailers. Industry studies and manufacturers are calling for the rapid installation of thousands of charging points along Europe's highways. The head of Daimler Truck estimates that around 50,000 standard and fast charging points will be needed across the EU by 2030, while the EU's current plans only provide for around 17,000. This discrepancy jeopardizes the achievement of registration targets for electric trucks. The status quo is that fast charging stations for trucks are currently hardly available along important routes – a stumbling block for freight companies that depend on reliable route planning.Insufficient charging capacity for huge amounts of energy: Today's charging systems are reaching their limits when it comes to the amounts of energy required. Fast chargers for passenger cars typically deliver 150–450 kW at 1,000 V. An e-truck-eTrailer combination with an 800–1,000 kWh battery would therefore need several hours to fully charge. For acceptable charging times of, for example, ~30 to 45 minutes (corresponding to a driving break), charging capacities in the megawatt range are required. Technically, this is already being prepared as the Megawatt Charging Standard (MCS), but despite announcements, such 1–3 MW charging technology is not yet in practical use. This means that the infrastructure must not only be expanded, but also brought up to significantly higher performance classes. Until then, battery charging on long journeys will either remain time-consuming or require more charging stops with partial charges, which complicates logistics and makes the whole concept extremely expensive.
High costs of intermediate charging at public infrastructure: The energy costs for electricity charged on the road are currently often high – not least due to the investment costs for high-performance stations and grid connections, which are passed on to the price. In Germany, electricity tariffs at public fast-charging stations are now averaging around €0.75 per kWh for customers without a provider contract, and the trend is rising. In some cases, prices of over €1.30 per kWh are even being charged. By way of comparison, household electricity costs around €0.30–0.40/kWh, and for businesses as much as €14/kWh, while diesel costs around €1.20–1.50 per liter. This means that a spontaneous stop to recharge while on the road can reduce the cost advantage of electric trucks and e-trailers or even make them more expensive than diesel, especially if high power charges apply. In addition, operators have to make massive investments in transformers, grid connections, and buffer storage, which means that the infrastructure costs per location run into the millions. These expenses are indirectly passed on to operating costs in the form of charging fees and/or government subsidies.
These challenges show that, in addition to the vehicle itself, the ecosystem surrounding it must also be mature in order for battery-electric long-haul trucks to succeed in the market. The following slides highlight a technical solution that was already presented at last year's IAA and addresses many of these issues at once: battery swapping infrastructure.
Battery swapping infrastructure: opportunities for long-haul applications
In view of long charging times, insufficient charging points, and high costs, the concept of battery swapping is coming into focus. This involves replacing an empty vehicle battery with a fully charged one at a station within a few minutes. This concept offers several opportunities to overcome the above-mentioned hurdles:
Minimal downtime and flexible energy supply: A battery swap typically takes only 3–10 minutes, depending on the system. For trucks and eTrailers, the aim is to achieve a swap time of around 5 minutes, as demonstrated by Chinese manufacturer CATL for trucks. Trailer Dynamics emphasizes that fast swapping drastically reduces downtime and gets vehicles back on the road as quickly as possible. A truck or eTrailer would therefore not have to charge for hours, but could continue its journey after just a few minutes, almost like refueling with diesel. This allows driving breaks to be used optimally without additional waiting times. The number of kilometers that can be driven each day increases, which is extremely attractive for logistics companies. Ultimately, a semi-truck earns money when it is on the road – a battery replacement system maximizes this operating time.
Relieving the power grid and using energy more efficiently: Battery exchange stations can serve as a buffer between vehicles and the power grid. The removed batteries are charged at different times and in a controlled manner, which smooths out peak loads in the grid. According to Trailer Dynamics, the grid load can be better distributed because the stations regulate power consumption throughout the day, thus using energy more efficiently. Unlike direct charging of many trucks and e-trailers at the same time (which requires enormous simultaneous peaks), a swap station can manage with comparatively moderate connection power, as only a few batteries are charged in parallel at any one time. Companies benefit from a centralized charging system that saves high investments in numerous distributed fast chargers and significantly reduces the required grid connection power. This load shifting also makes it possible to use cheaper electricity (e.g., at night when there is a surplus), which can reduce operating costs. The bottom line is that battery swapping infrastructure reduces peak loads on the power grid while enabling more e-trucks and eTrailers to operate smoothly.
Reduction of operating and investment costs: Higher vehicle utilization and the elimination of expensive fast-charging breaks improve the total cost of ownership (TCO) for electric semi-trailers. Swap stations bundle the charging infrastructure, which brings economies of scale: Instead of equipping every rest stop with expensive high-performance chargers, central swap hubs can cover multiple routes. The initially high investment costs of an automated battery exchange system (including the replacement batteries provided) are amortized more quickly when many vehicles use it. In addition, logistics companies could flexibly “book” battery capacity: a smaller battery is swapped for short trips and a larger one for long trips, so the electric semi-trailer truck does not have to constantly carry the maximum weight of batteries. This modular concept saves energy and costs, as only as much battery power is used as is actually needed.
Pilot projects already underway and success stories: Battery swapping is no longer just theory. In China, the concept has become established in the passenger car sector – manufacturer NIO operates over 3,000 swap stations and recorded more than 100,000 battery swaps in a single day on January 23, 2025. Around 80% of the energy that NIO drivers obtain on highways now comes from battery swap stations. China is also leading the way in the commercial vehicle sector: by 2022, almost 50% of new electric trucks sold in China were battery-swappable – especially in applications such as port and construction site logistics, where time savings and predictability are essential. The swap process there takes only a few minutes (approx. 3–6 minutes) per truck. Europe is following suit: A pilot project by Trailer Dynamics and DB Schenker will test an eTrailer with interchangeable batteries in long-distance transport in 2025. The swap technology is designed to take around 5 minutes and maximize the operating time of the semi-trailers. DB Schenker sees battery swapping as “a key role in overcoming the challenges of charging infrastructure” and an important accelerator for the market ramp-up of zero-emission heavy-duty vehicles in Europe. Battery manufacturer CATL is also investing in such concepts and contributing its expertise in battery and station technology. This practical experience and these projects underscore the feasibility and advantages of the swap infrastructure.
Concluding slide:
The electrification of long-haul truck transport is technically and economically challenging, but at the same time indispensable for climate-friendly logistics. Battery-electric trucks and trailers offer enormous opportunities thanks to falling costs, long-lasting energy storage and superior efficiency. At the same time, range, charging infrastructure, and charging times still pose hurdles—this is where the battery swapping infrastructure can act as a game changer. It supplies e-trucks and e-trailers with energy in minutes, reduces downtime, protects the power grid through intelligent charging, and makes operations more predictable and cost-efficient. Initial studies and pilot projects are showing promising results, meaning that battery swapping could become particularly important for heavy-duty long-distance transport. If industry, energy suppliers, and politicians work together to drive forward the standardization and development of such systems, new opportunities will open up for rapidly decarbonizing road freight transport – without sacrificing the flexibility and efficiency that the logistics industry needs today.
The change has begun, and battery swapping stations could prove to be a key infrastructure for the climate-neutral logistics of tomorrow. The coming years offer the opportunity to turn this vision into reality with decisive action.
Sources: This paper is based on current studies, specialist articles, and pilot reports, including those from EnBW, Fraunhofer, electrive.net, InsideEVs, Klimareporter, ICCT, and industry projects (DB Schenker/Trailer Dynamics), as referenced in the text.
