conformable wearable battery (US ARMY)


Powering today’s soldier: Wearable batteries will be stronger, yet safer for combat

One thing unites every soldier through the continents and across the ages: There’s no escape from hauling gear.

From weapons carried to the fight to the tools service members use to help them navigate and survive in hostile environments, a good piece of gear is everything. Thanks to technology advances in portable electrical systems, today’s soldiers pack capabilities and a level of lethality that was the stuff of science fiction in their grandfather’s era.

That’s where the conformable wearable battery comes in. Since 2011, the CWB has provided portable power that lets soldiers navigate, communicate and designate targets. Though the CWB can last through a three-day mission, it’s contained in a battery pack slim and light enough for soldiers to tuck into their tactical vests. Better yet, the case is flexible, so it moves with the soldier’s body, offering a new level of comfort when it comes to wearable batteries. Plus, it’s tough enough to take a beating.

The CWB provides solutions to two core challenges faced by the overloaded soldier: weight and power source.

The first challenge is weight. As the military adds more devices to help soldiers complete a successful mission, the more important it is to focus on managing the weight they carry. That brings an intense focus on packing only the essentials. Any ounce that doesn’t contribute to the mission or survival must be left behind.

At the same time, soldiers need access to enough watts to last a three-day mission. Just over a decade ago, options for portable power sources were limited. That left warfighters no other option but to find nooks and crannies in which they could stuff the several dozen AA batteries they needed. Or, they might carry a bulky brick battery that bounced uncomfortably in their packs.

Today’s CWB products solve these challenges by offering a high-powered but ergonomic battery that soldiers can comfortably wear next to their chest.

Still, the military of a great nation will never stop pursuing innovation to help soldiers be more successful in their missions and on the battlefield. Envision the warfighters of the coming decades. They will be even more lethal, with greater capabilities to work efficiently, but with better protective gear. That means soldiers will always eventually need access to more power, not less.

The following offers a look at two major areas to look for advancements in CWB: improved capacity and soldier safety.

Higher capacity cells, better run time

In an uncertain world, one thing is sure in the battery-design space: If there’s a way to increase energy capacity in the lithium-ion battery cells of a CWB unit, the military will have a need for it. The standard battery packs of today contain 150 watt hours. For most platoons heading out for a three-day mission, a pair of CWBs per warfighter will suffice to operate their navigation gear and stay in communication with home base.

But it won’t be long before the 150-watt CWB is outdated, and 200-watt packs will be common. As advances in battery chemistry improve, so will the top capacity, so it won’t be long before high-powered 250- and even 300-watt CWB units are in the hands of soldiers.

Within that growing need of power, the core demands will stay the same: More power in the least amount of space, at the lightest possible weight. If engineers could design a bigger battery, their job would be easier. The challenge is that soldiers are getting outfitted with more electronics that require ever more power, but there is still a need to reduce the soldier’s weight load.

As lithium-ion battery chemistry advances, it is possible for battery makers to fulfill the expanding needs of the modern military. However, the rise of higher-capacity cells raises another consideration, and that centers on preserving the safety of the soldiers.

With great power comes great responsibility

In the near future, soldiers will be carrying CWBs with a higher energy density than current models. These higher-powered batteries will meet the military’s ever-burgeoning energy needs without adding bulk or ounces. However, adding energy density does add another wrinkle to CWB engineering. Consider what happens when these soldiers, with battery units worn close to their bodies, are involved in a firefight. If the CWB isn’t designed with the right safety features, it can endanger soldiers. 

When a battery case is punctured or crushed, the energy contained inside escapes. Escaping energy creates high heat in seconds, which transfers to the neighboring cells. Finally, as temperatures of the battery cells reach 800 degrees Celsius, the battery pack will ignite, or worse, explode.

One way to keep battery cells from exploding in combat and other dangerous situations involves applying chemical, mechanical and electrical engineering to create an anti-thermal propagation system that safeguards the soldier from fire.

This can be accomplished by placing a thermal block between the battery cells to prevent the transfer of heat or thermal runaway. Another way is to do it through anti-flame suppression. That’s where the battery releases an anti-flame substance to prevent the escaping gases from reaching that explosion-inducing flashpoint.

Another way is to do it through anti-flame suppression. That’s where the battery releases an anti-flame substance to prevent the escaping gases from reaching that explosion-inducing flashpoint.

Because soldiers take these CWBs to some of the most extreme environments and often highly dangerous situations, there’s no room for letting up on safety for ongoing improvement.

Wearable batteries of the future: Power packed, battle tough

Bottom line, soldiers need a power source that can outlast a multi-day mission, and these needs will only grow as warfighters acquire more and better equipment. Given the dangerous conditions of the battlefield, however, it’s critical wearable batteries don’t put soldiers in harm’s way.

It’s important that military leaders be highly selective with the battery manufacturers they collaborate with. They must partner with firms that are just as committed to innovation as they are to focusing on increased capacity and enhanced safety features. 

About the Author

Wm. Mark Batts is principal system engineer, government programs and support, at Inventus Power.

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