The landscape of industrial automation is rapidly evolving, with Autonomous Mobile Robots (AMRs) and Automated Guided Vehicles (AGVs) becoming cornerstones of modern operations. To truly unlock their potential, especially in demanding 24/7 environments, the choice of power source is paramount. This blog post summarizes a recent session featuring Robin Schneider, Director of Marketing at Green Cubes Technology, and John Barrilleaux, Senior Sales Manager at Hubtex, who explored how lithium-ion battery technology is enhancing AMR performance, focusing on advantages in safety, efficiency, and sustainability. A key takeaway emphasized throughout the discussion is that the battery is the true "heart and soul" of the AGV/AMR, and its integration must be considered from the very beginning of the design cycle, not as an afterthought.
The Evolution of Industrial Automation and Electrification
Hubtex, a German sideloader manufacturer, showcases this transformative shift, having transitioned to 100% electric side loaders, moving away from internal combustion engines due to the undeniable benefits of efficiency. Barrilleaux highlighted that advanced features like electric steering can drive average power consumption down to as low as 3 kW per hour, while electric operations significantly enhance safety through features like electric brakes and collision avoidance systems.
True automation for forklifts and AGVs extends beyond simple movement, encompassing complex functions such as:
- Mapping: Translating the real world into a digital environment for navigation.
- Obstacle Avoidance: Detecting and routing around obstructions.
- Intelligent Routing: Adapting paths when routes are blocked and communicating changes across a fleet via a "mother ship" server.
- Load Detection: Identifying load presence, protrusions, damage, and weight.
- Precise Positioning: Accurately placing loads in racks or on assembly lines.
- Lift Capabilities: Managing height and mass deflection in rack systems.
These sophisticated operations require robust supporting systems, including software, on-board Industrial PCs (IPCs), and critically, advanced battery management systems (BMS) to monitor and control power flow, enabling seamless communication with the fleet control. Barrilleaux noted Green Cubes’ BMS has a user-friendly interface, simplifying integration through customizable settings.
Lithium-Ion: The Powerhouse for Modern AMRs
Schneider explained the inherent advantages of the lithium-ion battery: they offer superior energy and power density, making them the closest alternative to internal combustion engines and the default choice for modern electrification, from smartphones to electric vehicles.
Key benefits of lithium-ion technology for AMRs include:
- Superior Performance: Delivering consistent power with a very flat discharge curve, ensuring fast lifting and travel speeds throughout the battery's charge cycle.
- Extended Service Life: Typically offering over 3,000 cycles with warranties often extending to five years, even under 24/7 operation.
- Fast and Opportunity Charging: Enabling charging in under two hours, and in some advanced cases, as low as 45 minutes with multi-voltage technology, allowing for true opportunity charging during short breaks or downtimes.
- Enhanced Safety and Sustainability: Eliminating hazardous fumes, acid spills, and the need for battery watering, common with lead-acid systems, contributing to a lower carbon footprint.
The BMS is vital, performing functions like voltage, current, and temperature monitoring, safety disconnects, state of charge (SOC) and state of health (SOH) calculations, and cell balancing. Cell balancing is crucial for maintaining usable capacity over time and preventing safety risks from overcharge or underdischarge.
Maximizing ROI: Efficiency and Total Cost of Ownership
Lithium-ion batteries significantly impact the total cost of ownership (TCO). They can increase productivity and lower TCO by approximately 30%. With 98% energy efficiency compared to lead-acid's 80%, lithium-ion can reduce utility costs by about 20%. Other TCO benefits include lower maintenance requirements due to the flat discharge curve, 100% asset utilization through continuous opportunity charging, and reduced floor space needs by eliminating battery handling rooms, ventilation, and eyewash stations.
A compelling case study involved Boeing's omnidirectional AGVs, operating 24/7 since 2018 with 48V 200Ah lithium-ion batteries. Despite older cell technology, these batteries, constantly opportunity charged, maintained over 80% of their original capacity after likely 3,500+ cycles, far exceeding their initial 1,000-cycle rating. This stands in contrast to a lead-acid system used for copper coils, which required dedicated charging rooms, acid abatement, and fume management, a decision later regretted by the customer due to the limitations of early lithium-ion adoption.
Navigating Challenges and Ensuring Quality
While the benefits are clear, successful integration requires overcoming challenges and adhering to quality best practices. For instance, Barrilleaux noted the current lack of full standardization in communication protocols for mobile machines, though Green Cubes aims to simplify this with its CANopen-based BMS.
Schneider outlined critical quality best practices for evaluating lithium-ion suppliers:
- Evaluate Power Consumption Needs: A thorough commissioning process is essential to perfectly match the battery to the specific application.
- Prioritize Safety: Quality starts with a culture of safety, driven by management buy-in and employee empowerment.
- Rigorous Product Integration Testing: Includes vehicle-level function tests, CAN communication integration, and climate testing.
- Structured Failure Analysis: Implementing root cause analysis, containment, and corrective actions.
- Advanced Manufacturing: Utilizing computer-automated test equipment, automated laser welding, and computer-controlled torquing to minimize manual error.
- Cohesive Communication: Crucially important is seamless, ongoing communication between the AMR/AGV manufacturer and the battery supplier, spanning service, operations, engineering, and sales, often facilitated by a dedicated account manager.
Regarding battery chemistry, Barrilleaux highlighted Lithium Iron Phosphate (LFP) as the preferred choice for 24/7 industrial AMRs due to its intrinsic safety in environments with high-value equipment or flammable materials. While LFP might be heavier or larger, designing the AMR with this chemistry in mind from the outset makes it a superior option. On end-of-life considerations, Schneider noted that the recycling infrastructure for lithium-ion is still developing, but LFP cells, lacking rare-earth materials, can often be repurposed for secondary applications or safely disposed of.
The Future is Electric and Intelligent
The insights shared clearly demonstrate that lithium-ion battery technology is not just an upgrade but a transformative force in the realm of AMRs and AGVs. Achieving optimal performance, efficiency, and safety in an increasingly electrified future hinges on smart design, collaborative partnerships, and a deep understanding of advanced battery solutions. By embracing these principles, industries can unlock unprecedented levels of productivity and sustainability.