‘Mixed’ Approach to E-truck Manufacturing
Volvo Group CTO details OEM’s “mixed model assembly” strategy for battery and fuel-cell electric vehicles and provides insights on infrastructure and vehicle autonomy.
Electrification for truck, bus and off-highway equipment manufacturers brings more technology hurdles than for carmakers. Some of them are attributable to the issues involved with larger vehicles and the accompanying powertrain demands. Lars Stenqvist, the chief technology officer of the Volvo Group whose products include trucks, buses, construction equipment, as well as marine and industrial engines, recently discussed some of the electrification issues with SAE Europe editor John Kendall.
Volvo Trucks has been gaining experience with electric vehicle (EV) manufacturing through small-scale production of battery-electric versions (BEVs) of its FL medium-duty and FE middleweight truck ranges since 2019. Later in 2022, this experience will be used as the company also begins manufacture of electric variants of the heavy-duty FH and FM truck ranges. Volvo Buses also launched its BZL Electric chassis last fall.
“We made a thorough investigation when it comes to the production setup for electric vehicles, and we have come to the conclusion that we will use what we call ‘mixed model assembly’ on the main line,” Stenqvist shared. “So, if I invited you to the Gothenburg plant, or Ghent in Belgium, we would walk along the line and you would see one truck being built with a combustion engine intended for use with diesel, the next one would be a truck with LNG [liquefied natural gas] assembling the LNG tanks, and the third vehicle on the assembly line would be a battery-electric vehicle.”
To accommodate the mixed assembly, Volvo Group will install a number of new pre-assembly and sub-assembly stations on the lines. Stenqvist says that pre-assembly will be used for the power electronics components and batteries. “So, if we did walk along the lines, where we are normally dropping or installing the engine into the vehicle, on that very station, we would install the unit containing the power electronics,” he explained. “On the station where we are normally installing or assembling the fuel tanks, that’s where we are going to install and assemble the battery units. So that is the setup.”
Volvo is already in series production with the FL and FE. “We have learned a lot,” Stenqvist said. “Of course, it’s about the training of our assembly technicians, because we are introducing high-voltage components on the line.”
Flexibility with fuel cells
Volvo Group signed two important joint venture agreements in 2021, one of them to form cellcentric with Daimler Truck to produce hydrogen fuel cell modules. The company will use the same vehicle assembly techniques for fuel-cell electric models when production of these vehicles begins later in this decade.
Stenqvist believes that using these assembly techniques will provide the company with ample flexibility. “The question is of course, how fast could we ramp up production? It’s very difficult to answer,” he said. “But if you use this concept, you will be super flexible and you can also reuse your installations. You don’t run into those risks of saying that all of a sudden that old factory is completely empty. The intention is to reuse the equipment and to then balance between volumes of the different technologies.”
Late last year, cellcentric also signed a deal with Rolls-Royce Power Systems to supply the company with fuel cell modules that will be used to build emergency back-up power systems for data centers. Stenqvist says that its fuel-cell systems will not use methanol or ammonia as a source fuel.
“What we are looking at is to use hydrogen, directly into the fuel cell. You can have methanol or ammonia, etc., and in the shipping industry you will most likely see methanol and ammonia. Our intention is to store it on the vehicles as pure hydrogen, and it could be in gas or liquid form,” Stenqvist said. “In the long run, we need to work out at least a European standard for this, when it comes to filling stations. But when my engineers are working on the packaging and layout of the vehicles, we’re working on hydrogen storage on board the vehicle.”
Stenqvist would not offer a date when the production of fuel-cell electric vehicles (FCEVs) would start but says that it would be well before 2030. He also thinks that it is important the fuel is completely fossil-free. “We believe that we need three technologies in parallel: battery-electric vehicles, fuel-cell electric vehicles, and we also believe in the combustion engines for certain applications – but then running on renewable fuels, of course,” he said. “For us, it is important to have this in place before the end of the decade. That’s an important piece of the puzzle.”
Considering use cases, infrastructure
There is a general view among truck OEMs that there will be a split between BEVs, which will generally be used for local and regional distribution vehicles, and FCEVs, which will be generally used for long-haul vehicles. That may not always be the case.
“I think we will see national or at least regional differences in this,” Stenqvist reckoned. “There’s not a short line in-between exactly – these specifications will be battery electric and those will be fuel cell – but battery-electric vehicles definitely have advantages when it comes to city distribution and refuse trucks. Those guys come home to the depot every evening and can charge the batteries overnight. They will go battery electric. No reason to go fuel cell for them.
“The long haulers don’t really know where they are charging, where they are filling up,” he continued. “They will most likely be more towards the fuel cells – long haulers and heavy haulers. They can have quick refueling and you will gain payload by going fuel cell instead of battery electric. You will have certain advantages, but you will also have specifications where you’ll see in one region it will be battery electric and in other regions it will be fuel-cell electric because we will have issues when it comes to infrastructure and charging capacity.”
By way of illustration, Stenqvist puts forward an infrastructure issue: “When we’re talking about true long-haul, if you want to charge your battery-electric vehicle when having lunch, for example, after four hours driving, then you need to have a charger with a capacity of say 750 kW. It’s a lot, but if you then imagine that you have 1,000 trucks in parallel charging in a region or a country. We register 300,000 trucks every year in Europe, so charging 1,000 trucks in parallel is not much. Then 1,000 trucks is all of a sudden 750 MW at the same time.
“I compared it the other week to our nuclear reactors in Sweden – it’s the same magnitude as one of the nuclear reactors,” he said. “Every region, every country doesn’t have the capacity and the grid to cope with this. They will be more than happy to combine this with hydrogen re-fueling stations to balance out.”
Customers who purchase a Volvo truck today would be provided with a 43-kW charger, which, as Stenqvist points out, would be dependent on the electrical infrastructure available where the customer would want to install it. “We see national differences, we see regional differences, we even see local differences,” he said. “So here we need to work very closely with our customers, talking about what kind of permissions they might need to obtain, giving them advice, but then also sharing our experience of producing the FL and FE.”
Volvo’s second joint venture, announced late in 2021, is also with Daimler Truck, as well as Traton Group, the Volkswagen-owned commercial vehicle enterprise that includes MAN and Scania. Under the joint venture the partners plan to install and operate 1,700 high-performance, green-energy charging points across Europe within five years of establishing the joint venture.
Views on autonomous vehicles
Volvo is already operating autonomous vehicles (AVs) in confined areas such as closed quarries or mines. “If you start with a confined area, it’s rather easy to solve the use case from a safety perspective,” said Stenqvist, who thinks it is very likely that we will see autonomous trucks in use in the next 20 years.
Stenqvist sees AVs passing through three phases. First, the confined sites, then an expansion on public roads in two phases. He describes the first phase as “first mile” deliveries. “For example, picking up a container at a port terminal, transporting it 10 miles or something like that to a logistical center, and those shuttles driving back and forth, back and forth,” he said. Safety would again be paramount, and operations would be at low speed initially. Detailed mapping could be built up around the routes and infrastructure could be adapted if necessary.
The final phase would be on public roads. Stenqvist acknowledged that it presents a huge engineering challenge to achieve it, involving detailed mapping, designated vehicle lanes, type approval, testing and restricted operations. “Everything we are learning in confined [sites], we bring with us to the port terminals; everything we learn at the port terminals, we bring with us to the highways,” Stenqvist said. “I’m a true optimist, but it is definitely a challenge, and we will not release anything before we feel that it is safe.”