Tractors a good fit for next-gen batteries

In the construction, agriculture, and mining (CAM) industries, electrification is an uphill battle, says IDTechEx senior technology analyst Dr James Jeffs.

“In these industries, if a machine runs out of battery, the operators will soon start losing money,” he says.

“Moreover, these industries have a broad spectrum of machines, each with unique use cases.”

IDTechEx’s new report Battery Markets in Construction, Agriculture and Mining Machines 2024-2034 shows CAM machines require a diverse range of battery solutions to cater to their individual needs, especially in agriculture such as tractors.

New Zealand “electric cherry orchardist”, Rewiring Aotearoa chief executive and NZ Zero’s Mike Casey has introduced the Monarch electric tractor to Kiwis and was at the recent Mystery Creek Fieldays with one.

“For the most part, the purpose of a tractor is to drag machinery through a field,” says Jeffs.

“Sometimes, this work is low intensity, such as mowing grass in large fields. Here, the mower attachment isn’t too heavy and creates little resistance with the ground. On the other hand, ploughing a field creates lots of resistance and, therefore, uses lots of energy. Additionally, if a field has soft mud, the tractor will lose energy due to the tyres slipping.”

A 14-tonne tractor would typically use an engine with around 220kW (300hp) and it can expect to burn around 50L/hr in fuel, says Jeffs, adding that for comparison a 14-tonne excavator would typically use an engine with nearly 90kW (120hp) and expect to burn around 10-12L/hr in fuel.

“Both machines have hard and similar workloads; the tractor could be pulling a plough through the mud while the excavator is removing large quantities of material with its bucket,” says Jeffs.

“The key difference is that the excavator is at its peak load only momentarily as it breaks through the ground. The rest of the time is spent raising the bucket above the ground, twisting, dumping the load, then repositioning.

“The tractor, on the other hand, is working at a constant near-peak capacity. From a battery standpoint, this means that the tractor needs substantially more storage to give the same run time.”

Jeffs says the second challenge for electrifying tractors is chassis size.

“While large construction machines have large chassis to incorporate the battery, tractor chassis are a little more compact, even large 14-tonne ones.

“Additionally, large excavators can handle the weight of the battery, with many already having concrete ballasts for balance.

“Excessive weight could be an issue for tractors, especially when operating in wet mud. Moreover, tractors are more sensitive to the location of the weight, preferring an even weight distribution across the wheels for the best stability in the mud,” he says.

“So, not only do tractors need more battery power per hour than other similarly sized CAM machines, but they also have tighter constraints on where that battery can go. “

The third challenge with electrifying tractors is their uptime, says Jeffs.

“Again, this is an area where tractors are particularly unusual.

“Construction and mining machines tend to be in almost constant use, but many tractors have very seasonal work. They could sit dormant for large portions of the year, but come harvesting time on a large farm, they could be running 24/7 for days at a time.” Jeffs says high uptime in peak season means the battery needs to be capable of rapid charging to minimise downtime.

Sporadic usage means fewer cycles are needed over a vehicle’s lifetime, he says.

“Many tractors have life expectancies of around 2000-5000 hours, whereas large excavators might operate more than 10,000 hours over their life span.

A shorter life expectancy, with fewer cycles required, opens up battery options to more cutting-edge and emerging technologies.”

Battery technologies NMC and LFP are used almost ubiquitously throughout the automotive industry, says Jeffs.

“NMC offers good energy density but typically recharges slower compared to LFP.

“LFP has compromised energy density but is cheaper and can be recharged more quickly.

“Both have plenty of cycle life for agricultural applications, but IDTechEx suggests that other emerging options with higher energy density could offer a better fit.”

Solid-state batteries (SSBs) and silicon anode batteries are two emerging technologies that might work well in tractors.

“Both offer improvements in energy density when compared to NMC and LFP, making it easier to put more kWh of battery capacity onto the tractor, and both offer good to high recharging performance, minimising downtime.

“Finally, both offer the equivalent or higher safety than LFP and NMC. Unfortunately, both technologies are also very new, still in the early stages of commercialisation, and therefore are very expensive.”

IDTechEx says it has seen batteries as large as 1000kWh proposed for electric tractors.

The battery would likely exceed the cost of a regular diesel tractor of the same size, says Jeffs.

IDTechEx’s report forecasts that SSB and silicon anode will have a small market share of battery demand for agricultural vehicles once they are more mature, but demand will still be dominated by NMC and LFP, even in 2034.

The report considers 15 machine types across construction, agriculture, and mining, evaluating the needs of each and matching them up against 10 existing and emerging battery technologies.