Five benefits of ultracapacitors for Automated Guided Vehicles

In distribution centers, production lines, warehouses and other industrial settings, automated guided vehicles (AGVs) increase efficiency and reduce costs. However, the poor performance of their battery-based systems diminishes these cost-savings and efficiencies.

By Jeff Colton, Ioxus September 17, 2012

Manufacturers and users of AGVs are improving their applications by incorporating ultracapacitors with batteries for optimized energy storage. By using a hybridized system, AGV users receive the following benefits:

1. Continued power

The frequent bursts of high power AGVs need for lifting or dumping and their continuous energy use to travel throughout the facility drain battery life. With batteries, AGV users constantly switch out or recharge their batteries every six hours, making for an inefficient process. Given a typical work shift lasts eight hours, AGV owners lose resources by having to stop operations mid-shift to replace or recharge batteries, not to mention the 20 to 30 minutes it takes to swap batteries – time that could be used more productively.

Ultracapacitors provide peak power, and because they charge quickly, they allow an AGV to operate for a full eight-hour work shift. Plus, with in-floor inductive charging, ultracapacitors can not only charge within seconds, but also extend the overall lifespan of the energy storage system to 10 years, releasing manufacturers from constant battery replacements. Pairing an ultracapacitor with batteries improves battery performance and allows continuous AGV operation for 24 hours a day, seven days a week without the hassle of swapping batteries.

2. Free energy

AGV users can take advantage of ultracapacitors’ ability to charge quickly for regenerative braking. The ultracapacitor captures energy that otherwise would be lost when an AGV stops to load or unload its payload. The AGV then uses this recaptured energy as power to accelerate and move from one inductive charging location to the next station.

Regenerative energy is useful in forklifts, which are widely used in warehouses and distribution centers. Batteries and other energy storage options are not ideal for forklift performance since most forklift duty cycles accelerate multiple times within seconds. Because ultracapacitors charge quickly, they capture the regenerative energy of these frequent accelerations, improving forklift operating performance.

Regenerative braking increases fuel efficiency, which decreases the carbon footprint of AGVs. This also improves productivity at both the individual machinery level and the plant level, which boosts overall profits.

3. Reliability

AGVs benefit from enhanced efficiency and optimal performance by using a hybridized power source. Since ultracapacitors function well in a wide temperature range (-40 to 70 degrees Celsius), they can offset batteries’ weak performance in harsh temperatures and ensure AGVs operate properly, regardless of environmental conditions. This extends the battery’s lifespan, which in turn increases the life and performance of the AGV as a whole.

Further proving their dependability, ultracapacitors are rugged and reliable in emergency situations. Having passed multiple crash tests, ultracapacitors can withstand the demanding plant environment. And in the event of emergencies, ultracapacitors can provide enough energy to reposition the AGV to a safe location or for peak shaving to lower the power to a safe, manageable level to prevent accidents.

4. Smaller size

Pairing ultracapacitors with batteries reduces the size of the overall energy storage system and decreases vehicle weight. Manufacturers can select a smaller, high energy density battery to complement the ultracapacitor’s power density based on the AGV’s energy requirements.

5. Extended value

Ultracapacitors are designed for a high cycle life. Compared to batteries, ultracapacitors have a 1,000 times greater cycle life, which means they can operate for 10 or more years without replacement. Batteries, on the other hand, typically last about two years. Implementing ultracapacitors in AGVs results in an extended lifespan for the vehicle; an AGV energy storage system with an ultracapacitor has up to four times longer life than one operated on batteries alone. This long life also means cutting replacement costs, which improves the total cost of ownership of the AGV.

Since ultracapacitor costs have dropped 90 percent in the last decade, more and more manufacturers are using this technology. With a payback period of just 18 months and no required maintenance, manufacturers receive a positive return on investment during the ultracapacitor system’s long lifespan, which will further boost demand for AGVs equipped with ultracapacitor technology.

Jeff Colton is vice president of sales, North America at Ioxus. Jeff can be contacted at jcolton@ioxus.com or 858-663-1609.