Long-haul and high-payload vehicles are responsible for approximately a quarter of C02 emissions from road transport in the EU. In light of this, there is a great incentive to electrify the freight transport industry moving into a sustainable future.
The design and development of high-payload electric vehicles (EVs) comes with a range of challenges that are greater than that of their smaller counterparts. Battery efficiency, charging speed and battery degradation are hurdles in the way of mass electrification. That said, new electronic systems are being developed to improve these factors to meet the 2025 and 2030 C02 emissions targets.
But why are these challenges preventing heavy-duty fleets from transitioning to EV alternatives, and what are the systems that can help achieve this?
One of the most significant differentiators between smaller commercial EVs and high-payload EVs is the impact of weight on battery capacity. Greater energy is required to transport multiple tonnes worth of cargo long distances, so they have greater demands of battery capacity as a result. Moreover, the weight of the battery packs themselves have an additional impact on capacity; Volvo’s heavy-duty EV trucks have 5-6 battery packs with a total of 450-540 Kwh, but account for an additional 2.5-3 tonnes in weight. This leads to a challenge of balancing power capacity for charge range with available weight for cargo.
The greater battery capacity demands of high-payload EVs directly results in the challenge of charging speed and efficiency. Standard and easily accessible commercial charging solutions such as AC are sufficient for overnight charging, taking approximately 10 hours to reach a full charge for standard EV truck capacity. That said, the long distances and around-the-clock use of many long-haul EVs demand regular charging that can negatively affect efficiency. For example, a DC charging solution takes approximately 2 hours to charge a high-payload EV; EU regulations require drivers to take a 45 minute break every 4 ½ hours, which is a potential loss of 75 minutes on the road when the charge is fully depleted.
The three most significant factors that influence lithium-ion battery degradation are temperature, state of discharge and load profile. State of discharge refers to the amount of power that is used before the battery is recharged, and load profile is the variations of power that is demanded during its use. Out of these three, temperature is the most significant stress factor, which is a challenge for long-haul EVs that are in regular use, driving at varying speeds and over vast distances. Battery maintenance and replacement costs can become a real problem in the long-term.
Battery management systems (BMS) not only protect from performance degradation and thermal runaway, but continually optimise battery performance via advanced systems. BMS monitors the state of discharge and load profile of batteries in real-time, ensuring it is within safe operating range by controlling charging and discharging. Moreover, BMS allows optimum battery capacity to be realised when cell-to-cell balancing is employed to equalise the state of charge. The result is long-haul EVs that can travel safely, further, and for longer.
As temperature is the most significant factor in terms of li-ion battery performance, efficiency and degradation, controlling these parameters is vital in maximising the potential of long-haul EVs. Thermal management systems are holistic technologies that control the temperature environment of EV batteries. These can range from air, liquid and refrigerant cooling, and help extend the lifespan and driving efficiency of long-haul EVs that generate significant heat from the number of battery cells in use at one time.
Like with any EV, charging infrastructure is what dictates their application in specific places. In regards to high-payload applications, they demand high power charging throughout their route to maximise efficiency and limit stationary charging times. Megawatt Charging Systems (MCS) are a revolutionary technology specifically designed for the ultra-fast charging of high capacity vehicles. They are still very much under development, but pose a promising future for the design of long-haul EVs.
The need for road freight electrification is clear when looking at their C02 emissions. Because of this need, the constant development and optimisation of EV systems are seeing regular advancements in battery efficiency, charging, and lifespan; a zero emission in long-haul vehicles is gradually becoming realised.
In order to be ahead of EV competitors, Dalroad’s team of independent engineers can advise you on your EV design to optimise specific systems and components. You can have a more sustainable approach to vehicle production and design without losing efficiency with your fleets. Contact a member of our team today to realise the benefits of fleet electrification.
