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Kuchera Defense Systems (Kuchera), a Windber, PA-based defense contractor, has developed the ODIS unmanned ground vehicle (UGV), which is currently in use by law enforcement and the military (Figure 1). However, the company received some interesting feedback. Customers were impressed with the operational performance of the platform, but there was one significant problem. Because ODIS was battery operated, the run-time capacity was depleted in less than an hour, which was unacceptable for many anticipated deployment scenarios. A new alternative to batteries was quickly needed to make the ODIS fully mission ready. Commercially available fuel cell technology from Jadoo Power proved to be the solution for this engineering challenge, and serves as an example of how fuel cells can serve as a viable option in the power design of military systems.

In less than one month, Jadoo retrofitted one of the ODIS robots with a fuel cell system. There was no impact to the external appearance or robotic functionality in the new plat-form powered by fuel cells. However, ODIS now ran for more than double the time when previously powered by batteries.

Jadoo has developed its fuel cell technology through a strategy of focusing on applications that can take immediate advantage of the benefits of predictable, portable, efficient power. Most initiatives for fuel cell design are in the area of automotive power (several kilowatts), and a small amount of development focuses on micro applications of less than 20 W. However, there is limited fuel cell development in the portable space (Jadoo's area of focus), yet this power regime has proven highly valuable for emergency preparedness and first responders who need off-grid power support. Battery replacement represents another application for fuel cell technology, but is primarily an opportunity within the military, where weights vs. runtime trade-offs are critical.

One military application where the limitations of battery technology are apparent, due to the relatively high power levels required, is in UGVs. In an ongoing effort to minimize the risk of human injuries or casualties, UGVs are becoming increasingly popular with military and law enforcement agencies. They are now being used to perform a multitude of tasks including:

• chemical weapons detection;
• vehicle security checkpoint inspection;
• search and identify sniper situations inside buildings;
• safely identify key targets; and
• assist in bomb disposal.

Therefore, the UGVs may become a key component of the U.S. Army's Future Combat System (FCS). FCS is the Army's modernization program consisting of manned and unmanned systems. The two are connected through a common network providing communications and functionality that allow soldiers and commanders the capability to execute successful campaigns in complex environments. As the military develops the FCS to become a more information- and communications-centric force, they are beginning to realize that supplying electrical power to military systems of the future will be a major challenge.

At present, the U.S. military solves this dilemma by deploying a combination of batteries, solar panels and generators. In small unmanned aerial vehicles (UAVs) used for tactical reconnaissance, batteries are the most common choice for power. Cost, reliability and weight issues surrounding the use of batteries has led the military to seek alternative power solutions. An example of the runaway cost associated with battery technology can be seen with the deployment of a single UAV in theater. It could cost as much as $25,000 per month in batteries, not including the logistics and related costs involved in shipping the batteries to the field. The first step is to replace the current solution with rechargeable batteries instead of the standard primary BA5590 batteries. Unfortunately, rechargeable batteries suffer from the memory effect, self-discharge and other forms of degradation. These are essentially the same failure mechanisms that can be found in a notebook computer battery: these batteries will hold a charge and provide operating power for hours when new, but slowly loose the capability to deliver the same runtimes over their operational lifetime, sometimes requiring replacement.

Over the past decade there have been significant advancements in the capabilities of electronic communication devices and applications. Unfortunately, there has not been a similar growth within the technologies of battery power sources. The military has now identified that fuel cells could be the necessary answer to solving this significant demand for energy storage. Jadoo has also developed a laptop docking station that can be powered from one of its fuel cell systems, and it may be possible for designers to adapt this configuration into a dedicated power system for ruggedized data terminals.

Inside a fuel cell, hydrogen from a fuel canister and oxygen from the air combine to produce electricity and water vapor. No fuel is burned in this simple electrochemical process, so no polluting byproducts like carbon dioxide are emitted. As long as there is a supply of hydrogen, electricity is produced in a fuel cell. Scaling the runtime of a fuel cell system is directly related to the amount of hydrogen that can be stored in a small volume.

Jadoo has also commercialized hydrogen storage using metal hydrides as a medium to store hydrogen in a component called the N-Stor. These units (Figure 2) are filled with a metal hydride that soaks up the hydrogen gas like a sponge, tripling the amount of hydrogen that can be packed into the same small canister. The significant benefit of this storage technology is the fact that metal hydride-based fuel storage devices do not suffer from self-discharge, memory effect or other degradation in day-to-day to use. They can also be rapidly refilled from a pressurized source of hydrogen.

There are more than 3000 companies, universities and organizations working on fuel cell technology research, components and products. The issue is that while this effort will be ultimately beneficial, the most important aspect of fuel cells to the military designer is the ability to package the technology into commercialized, cost-efficient components. For the contract with Kuchera, Jadoo simply repackaged its commercially available N-Gen fuel cell system (Figure 3) to fit within the housing of the ODIS (Figure 4). The N-Gen is then supplied with hydrogen from the N-Stor, which can be inserted into the ODIS through an external port.

The N-Stor is a unique fuel storage device. It uses a digital intelligent interface that acts as a fuel gauge, communications port and safety mechanism. The N-Stor is engaged to the N-Gen through a twist-action mechanical interface, and can produce 100 W of power at 12 Vdc. The N-Stor's electronic interface passes critical information between the storage canister and the fuel cell regarding the type and amount of fuel it contains, the serial number, the date of manufacture, operating algorithms, etc. When an N-Stor canister has been depleted of hydrogen, it can be recharged with a Fill Point station (Figure 5) connected to a supply of hydrogen.

Additionally, the repackaged N-Gen used for the ODIS UGV was hybridized with a set of supercapacitors that allowed the platform to have access to increased power needed to accelerate rapidly to its full operating speed from a total standstill. The hybrid circuit also allowed ODIS to deal with changes in power demand during normal operation.

Many current and emerging military applications are in need of a power solution that is better than what modern battery technology can provide. As fuel cell technology develops, it is becoming evident that alternative power products cannot only replace current batteries, but that they can do it with the added benefits of longer runtimes, no degradation, no memory effect or special maintenance; they can even offer multiple fueling options. Fuel cells systems are defining the next generation of portable power technology.

Muralidharan (Lee) Arikara, co-founder and vice president of business development at Jadoo Power, has 13 years of experience in the fuel cell industry and an MSEE. He led the market research and product introduction strategies for Jadoo's surveillance and professional video products. Arikara is also a co-recipient of the Entrepreneur of the Year award.