Objective
In this innovation-oriented project, SUNCAR and KTEG collaborated on the development and market testing of a 15-ton class battery-electric mobile excavator. These machines are primarily used for inner-city construction sites, as they are permitted to operate on public roads with the appropriate certification.
The project’s goal was to electrically optimize the mobile excavator’s efficiency through a fundamentally redesigned drive concept and to create a resource-saving and environmentally friendly alternative to diesel-powered machines. Local emission-free operation and significant noise reduction are key advantages that make urban use particularly attractive. Furthermore, electrification has a positive impact on the user experience, as full power is always available for every movement. The reduced energy requirement is also reflected in even lower operating costs and reduced maintenance efforts compared to diesel excavators.
Approach and Technological Methods
As part of the project, SUNCAR and KTEG developed two prototypes with different electrical configurations. This allowed for the comparison of various drive concepts: a fully hydraulic, an electro-hydraulic, and a quasi-fully electric system. A key component of the optimization was improving the drive concept to use energy more efficiently and enable recuperation into both hydraulic and electrical storage systems. This presents a variety of new challenges, particularly because the remaining hydraulics must continue to function as usual.
Furthermore, special attention was paid to battery technology. The choice of battery influences not only the excavator’s range and performance but also the charging times and the overall service life of the system. Therefore, various battery types and their potential applications were analyzed.
Challenges and Solutions
One of the greatest challenges was the limited availability of electrical and mechanical components. Long lead times and immature product lines led to a complex selection process. Additionally, a comprehensive redesign of the hydraulic routing was partially required to integrate the new systems without occupying excessive space. The thermal management of the battery was also optimized, as the efficiency of the battery cells depends heavily on operating conditions. Targeted cooling and an improved energy management system were implemented to maximize battery life and ensure consistent performance.
Despite the many new aspects of the project and the associated challenges, a component architecture was ultimately developed that enables a full working day with just one battery charge. This represents a significant advantage over previous electric excavators, which often have shorter operating times. The modular design of the battery unit allows the system to be adapted to different operating conditions, ensuring high flexibility in construction site operations.
Results and Conclusions
Prototype testing has so far shown a significant reduction in energy consumption. In particular, the configuration with the direct electric drive achieved savings of around 40% compared to a purely electro-hydraulic variant. In addition to energy savings, noise measurements were conducted to further investigate the benefits of electric drive technology on urban construction sites. The results showed a significant reduction in noise pollution, which is a decisive advantage, especially in densely populated areas.
Furthermore, field tests were conducted with different driving modes to find the optimal balance between performance and energy efficiency. The collected data was incorporated into the further development of control algorithms to further minimize energy consumption and maximize operational safety. Charging cycles and integration into existing charging infrastructures were also of particular importance. The potential for fast-charging systems and swappable batteries to further improve operations was evaluated.
In conclusion, battery-electric mobile excavators represent a promising solution for the sustainable construction sector. The combination of high energy efficiency, reduced emissions, and improved working comfort makes them an innovative and economical alternative for urban construction site operations. In the long term, demand for such machines is expected to rise as more and more cities demand emission-free construction sites. The insights gained from this project form a solid basis for the further development and series production of this new generation of mobile excavators.
More about KTEG electric excavators: https://kteg-company.com/de/zero-emission
