Caterpillar testing new battery electric LHD
A proof-of-concept battery electric LHD (load-haul-dump) machine developed by Caterpillar will soon be moving muck in a Canadian underground mine, continuing the validation of a Cat R1300G test unit that began in early 2017 at the Caterpillar Peoria Proving Ground.
While the test unit itself does not represent the final design, the prototype machine is a proof of concept for packaging and performance of a lithium-based energy storage solution Caterpillar plans to bring to the LHD market.
“Our customers are planning for deeper mines with very high ambient rock temperatures where ventilation costs are pivotal to making the mine viable,” said Jay Armburger, a Caterpillar product manager with responsibility for underground technology. “One means of reducing ventilation demand is through electrification of the mining equipment.”
Caterpillar has successfully integrated electric drive train technology and components in a number of surface machines and will bring this knowledge to the underground market. The company has over 250 patents in the electric drive and energy storage fields, and has developed products like the D7E dozer, F-Series Asphalt Pavers, 794 AC and 795F AC large mining trucks, the recently introduced 988K XE wheel loader, and even microgrid technology.
Setting high performance standards
The program started with a full production study and data analysis of the diesel machine in order to set a baseline. Once this was accomplished, the transformation of the R1300G to a battery electric proof of concept began. Modifications included removing the engine, transmission and torque converter, and then reconfiguring the engine end frame to accommodate the battery boxes and electric motors. The result is a battery electric powertrain driving a conventional and mechanical drivetrain (drive shafts and axles).
The R1300G proof of concept is an older machine without the benefit of efficient electro-hydraulics. As a result, it will drive worst case scenario loads on the batteries. The design of the new loader will enhance battery life through the use of load-sensing hydraulics driven by piston pumps such as those on the new Cat R1700 underground loader. The less-refined proof of concept machine will yield solid understanding of heat generation and cooling needs, performance criteria, space claim, and safety considerations in the day-to-day operation of the machine.
With the help of several customers who have visited the proof of concept and operated it at the proving ground, Caterpillar is getting feedback to help drive the program forward. All of the customers who have visited the machine have indicated to Caterpillar that pursuing a system that is rechargeable on the machine is the right path forward. Recharging prevents the mine from incurring additional infrastructure costs or from having to manage or store replaceable battery packs. Instead, Caterpillar is focusing on fast charging of the batteries on the machine such that an operator can take a quick break and come back to a charged machine. In addition to developing the LHD itself, the program has been prototyping a robust charging station. The technology behind the charging station is unique to Caterpillar and uses Cat components and technology.
Caterpillar recognizes that the chemistries and technologies behind battery development are evolving rapidly, and the development team will continue to evaluate these changing technologies to better serve underground mining customers.
“We tried hard to break this machine and technology before sending it to Canada in September,” Armburger said. “With the results we’ve seen so far, we’re confident this R1300G proof of concept is giving us the answers we need to develop a machine that is safe and lives up to the Cat brand promise of durability and reliability.”
“In the end, Caterpillar is well positioned with deep expertise to develop the most optimized solution—from power generation to tire rotation,” he said.