Portable Power Products
Written by Matthew Cox
SOTECH 2010 Volume: 8 Issue: 6 (August)
Lightweight Battery Alternatives for the Grunt.
Infantrymen may soon carry a juice box-sized gadget that will eliminate the need for multiple batteries on the battlefield. The Protonex soldier power manager is designed to draw wattage from a common battery source and convert it to feed the different power needs of squad and platoon-sized radios, GPS units and other vital gear.
The SPM-611 power manager is one of several new power-related products that are the result of a push by the U.S. Army and Marine Corps in recent years to lighten the heavy loads ground troops struggle to carry in Afghanistan’s rugged mountainous terrain.
Infantry and special operations units often carry more than 100 pounds of equipment when patrolling on foot. In addition to weapons and body armor, ground troops have to haul extra bullets, fragmentation grenades, mortar rounds, weapons, food, water and extra batteries up and down Afghanistan’s steep, rocky terrain.
As a partial solution to this, the Army ordered tens of thousands of lightweight body armor plate carriers last October as an alternative to the service’s standard body armor vest, which can weigh around 30 pounds.
Another weight burden has always come from the amount of batteries grunts must carry to power all their high-tech gear. These can range from small AA batteries for night vision devices and GPS units to larger batteries such as the 2.6 pound BA-5390 that’s needed to power the Multiband Inter/Intra Team Radio and other communications gear. Troops can easily carry 10 pounds of batteries for a multi-day mission.
To combat the problem, the defense industry has focused its research toward finding new ways to help soldiers and Marines shed painful pounds of battery weight from their combat kit.
The Protonex SMP-611, which weighs just under a pound, can reduce the number of batteries needed by managing the power from one or two batteries to power up to six pieces of combat kit, said Greg Cipriano, vice president of marketing and business development at Protonex.
“You can hook any piece of equipment up to any power source with this box,” he said.
The SMP-611 measures 1.6 inches high, 4 inches wide and 2.3 inches deep. It has a two-port “energy scavenger” that can harvest power from solar panels, primary batteries, car batteries and battery chargers. It also protects against power surges and short-circuiting.
The devices features high-efficiency power conversion, Cipriano said, explaining that typical power converters use a portion of the available power to perform the conversion.
“For every 100 watts you use, you lose [approximately] 15 watts in the conversion,” he said. “With us you lose [approximately] two watts. Power is precious when you are carrying it.”
Protonex began working on the SPM-611 about three years ago and it is now ready for military testing.
“The system is smart,” Cipriano said. “This has really been quite a development effort on our part. We expect this product to be very widely deployed in the field over time.”
BATTERIES OF A NEW SHAPE
Some companies have moved away from traditional blockshaped batteries and designed prototypes shaped like the body armor plates soldiers and Marines wear against their bodies.
The concept involves better weight distribution to make the load easier to carry.
The BAE Systems Integrated Power Source (IPS) is designed to slide in front of the Enhanced Small Arms Protective Inserts that soldiers and Marines carry in their body armor vests.
“We did that because that is an area the U.S. soldier is used to carrying weight,” said Sean Martin, director of business development at BAE’s Personal Protection division.
The lithium-based system can power an MBITR, a GPS and two other devices at the same time.
The IPS is part of a larger effort know as Ultra Lightweight Warrior, a complete set of soldier equipment, from body armor to load-carrying pouches, designed to reduce weight wherever possible.
BAE is making the IPS available separately because the military personnel continue to call for this type of power source, Martin explained. “This is the single technology that has received the highest level of interest” at major defense shows such as the recent 2010 International Special Operations Forces Exhibition & Conference in Amman, Jordan.
In its current form, the IPS consists of two ESAPI-shaped power panels, a power-distribution module that controls the flow of power to each device and a power meter that lets the wearer monitor how many devices are connected.
When both power sources are in use, the system can power up to eight pieces of soldier kit, Martin said. The IPS is not limited, however, to the ESAPI shape. “We can reconfigure it to a certain degree,” Martin said, adding that they can be carried in the top panel of a rucksack.
Each power source holds several grids of circuitry that store power. The design allows the system to keep working even if a portion of it is damaged, Martin said. “We did a lot of the destructive testing to see how they responded to punctures. If you have a puncture in one area it will shut down that string and you will still have the energy to utilize.”
The IPS will supply enough power for a 72-hour mission, and its 100 watt hours can be restored in less than two hours. The system is still undergoing testing but should be ready by early next year.
Ultralife Corporation is also developing an ESAPI-shaped power source known as their “conformal” battery. The highcapacity, lithium-ion 18650 battery conforms to the shape of a soldier’s torso when it is placed behind an ESAPI plate.
“It disperses the load,” said David Modeen of Ultralife. “The thought behind it is how the soldier is carrying the load. It’s easier on the solder’s frame to carry it behind the chest plate rather than have a dedicated pouch on the hip.”
Over the past two years, Ultralife tested two versions of the battery—one made with lithium-ion 18650 and lithium-ion polymer technology.
The Army “wanted to assess a round going through the battery and what the reaction would be,” Modeen said.
In ballistic tests, the polymer version fared better. It merely smoked when shot with a 7.62 mm bullet. The same type of bullet caused a fully-charged 18650 version to catch on fire.
Despite the reaction, the company is pushing forward with a version of the lithium-ion 18650 battery. “Our take on it is, if the battery is sitting behind a chest plate and a round goes through the battery—the battery is not the problem,” Modeen said.
The high capacity version will have 11.6 amp hours and power any gear item that requires up to 16.8 volts. “This would be roughly about 20 percent increase capacity or run-time over the Li-145 battery,” Modeen said. The Li-145 is used in Land Warrior, the Army’s wearable computerized command and control ensemble.
The prototype is less than an inch thick and is designed to fit behind a medium-sized ESAPI in the Army’s improved Outer Tactical Vest. It’s in a rugged casing that is fully waterproof.
Ultralife officials said they are confident that there will be a market for the technology.
“We are not taking a wait-and- see approach on what the Army wants to do,” Modeen said. “We believe we have customers and there are markets out there. We are seeing this requirement come up over and over again.”
SMALLER BATTERIES AND CHARGERS
Ultralife is also trying to perfect a battery that’s half the size of its popular BA-5390 and delivers nearly the same power.
For the past three years, the company has been trying to move beyond its expertise in lithium-manganese dioxide, or MnO2, and work with carbon monofluoride or CFx, a material used in small button-style cells such as hearing-aid batteries.
The material has never been used in military applications because it’s expensive and it also tends to overheat, Modeen said.
“While it provides about a 50 percent increase in energy density over manganese dioxide, it runs extremely hot,” he explained. “There are heat management issues that have to be dealt with when ever you replace MnO2 with CFx.”
As a solution, Ultralife combined the two materials to “get the best of both worlds” in a smaller battery. “The soldier gets half the volume, half the weight and almost identical capacity of a 5390,” Modeen said, describing how the new battery weighs about 1.3 pounds compared to the 2.6 pound 5390.
Cost is another challenge with this new style of nonrechargeable battery that still has to be overcome. “The one hurdle we currently still face is the price of CFx is extremely high compared to MnO2.” Ultralife is working with companies that sell CFx to enter into negotiations on large-scale production that could bring the price down.
The program has received funding from U.S. Army Communications- Electronics Research, Development and Engineering Center to deliver 25 of these half-90 batteries for testing this fall, Modeen said.
In the world of multi-battery rechargers, Protonex is introducing a portable recharging system that uses methanol fuel cell technology. The M300-CX is designed to withstand the extreme conditions of the battlefield and support platoon-size units.
“This device was created specifically to support the recharging of batteries in the field by dismounted soldiers,” Cipriano said. “This is the state-of-the-art … it has a capability to charge six batteries” at a time. “The previous version was twice as big.”
The M300 measures 11.5 inches high, 14.5 inches and 9 inches deep. Despite its compact size, it weighs about 36 pounds without the 2-liter fuel cell cartridges needed for recharging.
“The idea is to support a platoon,” Cipriano said. “One guy carries this thing and other guys carry the fuel cells. Is it extremely portable? No. But it is portable, so we are definitely getting there. This is the first kind of breakthrough product in this area.”
A unit would dismount from vehicles or aircraft and carry the M300 for a short distance to where it could be stowed away in a patrol-base setting, Modeen said. “It’s not something you would carry all over with you,” he said.
The M300 produces 300 watts of power and will charge up to six BB-2590 or six Li-80 or Li-145 batteries simultaneously, he said. It can also be set up to power several pieces of equipment in a static position using a common power source.
The system will last for about 2,000 recharging hours, which dramatically reduces the logistics trail associated with disposable batteries, Cipriano said. “Just to get a battery out to where you are in Iraq or Afghanistan costs a lot of money.” ♦