NMC batteries for commercial vehicles: high-performant and safe

29 Oct 2024

The safety of NMC and LFP batteries is often compared. MAN has opted for NMC cells – they’re not only safe, but also extremely high-performance.

The batteries of commercial vehicles are subjected to considerable demands: they need to store as much energy as possible, in the smallest space possible, at the lowest cost possible, in addition to being lightweight, high-performance, quick to charge, long-lasting and safe in every situation. In its electric vehicles such as the new eTruck, MAN relies on battery systems which are especially suited to use in commercial vehicles, and which best meet the often contradictory demands on energy storage.

They are based on battery cells in which energy is stored using lithium ions. When the battery is charged, the lithium ions in the cell take on electrons, which they then give up again as the battery discharges – so that those electrons can flow through the electric motor and so drive the vehicle. Lithium-ion batteries can store more energy per kilogramme than other types of battery and therefore make a great choice due to their high energy density.

Complex energy store: The properties of a battery can be significantly influenced by the cell chemistry.

NMC cells optimised for commercial vehicles

The individual properties of a lithium-ion battery can be influenced by the use of different materials for the positive and negative electrodes (cathodes and anodes). In this context, experts speak of “cell chemistry”. MAN uses NMC cell chemistry (nickel-manganese-cobalt) in its batteries. The cathode is made of a blend of nickel, manganese and cobalt. This combination offers high energy density, stability and safety. The anode is made of graphite, a form of carbon.

Other batteries use LFP cell chemistry, which uses lithium and iron phosphate for the cathode. This material is also thermally stable, safe and durable, although it offers a lower energy density than NMC batteries. MAN has carried out intensive comparisons of the two technologies and has made a considered decision to use NMC cells for the current generation.

“We have developed, adapted and optimised the NMC cell chemistry,” reports Dr Michael Bernath, head of battery development at MAN. “We have been able to develop a battery that stands up to the tough conditions of day-to-day use in commercial vehicles. It offers high energy content at an economical price with low weight and compact size – and all without compromising on operational safety.” Every MAN battery is subjected to stringent testing to ensure its durability in every conceivable scenario. These tests are often stricter than legally required.

Expert: Dr Michael Bernath is a senior developer at MAN Batterie.

Stress test: MAN batteries are pushed to their limits in numerous tests - for road safety.

Meticulously monitored: the battery electronics immediately detect whether everything is in order or whether there is a fault.

Smart BMS and extensive testing guarantee safety

However, the safety of a vehicle battery depends on more than just the cell chemistry. The control electronics surrounding the energy storage also play an important role. At MAN, a battery management system (BMS) constantly monitors the condition of the cells. If, for example, an unexpected event occurs, the BMS takes internal measures to ensure a safe state. In the event of an accident, the BMS immediately disconnects the battery from the rest of the vehicle (high-voltage emergency cut-off).

In addition, the BMS uses an intelligent heating and cooling system to keep the battery within an optimum temperature range at all times – too high temperatures could damage the battery, while too low and performance is affected. The BMS also predicts how the battery is ageing on the basis of the individual usage profile. This means that its lifetime can be optimised and, if necessary, repairs or replacements can be undertaken. To summarise, we can say that the BMS improves efficiency and safety, reduces ageing and extends the lifetime of the battery.

All-round protection: there are many external influences that can pose a risk to the battery, but the MAN safety concept provides comprehensive protection for the components.

Expertise from the VW Group network

When it comes to cell chemistry, as well as battery software and hardware, MAN can make use of the knowledge of all the experts within the Volkswagen Group. And for maximum “Made in Germany” quality, the company is building a mass production facility in Nuremberg with a capacity of more than 100,000 battery systems per year. This enables MAN to keep its battery expertise in-house.

The results of developments over the last few years are plain to see: the useful life of the MAN BatteryPack in MAN eTrucks is up to 1.6 million kilometres, or up to 15 years, depending on usage. Furthermore, the MAN BatteryPack meets all the typical demands of commercial vehicles in terms of charging cycles, mechanical robustness, vibration resistance and lifetime. The combination of innovative technology and targeted safety measures means that MAN batteries are in no way inferior to LFP systems. What’s more, their high energy density and performance means that they offer advantages that make them especially suitable for use in commercial vehicles.