The U.S. Army is working on a flexible battery that soldiers can wear inside their armored vests.

The Conformal Wearable Battery, or CWB, conforms to the body, which Army officials say is a significant upgrade to traditional batteries that are rectangular and bulky.

The CWB provides more power, reduces the need for battery re-charging and spares, and serves as a single source of power for all worn electronic devices, said Christopher Hurley, an electronics engineer who leads the battery development projects team at Army Research, Development and Engineering Command’s Communications-Electronics Research, Development and Engineering Center, in a recent Army press release.

Hurley said the Army's standard batteries, the BA-2590 and BA-5590, were designed to be placed in battery boxes and large communication equipment and not to be worn by the soldier to power his electronics.

The CWB, however, is made specifically to be worn within a tactical vest, said Steve Mapes, product director for Soldier Power at the Army’s Project Manager Soldier Warrior.

"[The conformal battery] allows the warfighter to share space with other equipment that he has to carry on his load carriage," Mapes said. "When you slip a conformal battery into the protective vest and over the [Small Arms Protective Insert] plate, it's virtually invisible and transparent to the soldier. Now the soldier can still hang his magazine, grenades or flashlight over the battery. The conformal battery allows the soldier to share valuable, limited real estate."

Army engineers have developed six CWB prototypes since 2008. The goal has been to demonstrate a battery that is smaller, lighter, provides longer-lasting power and eliminates the need for a separate battery for each electronic device, Hurley said.

"We look to reduce a soldier's load with the number of batteries [soldiers] carry and consolidate that into as few batteries as we can," Hurley explained. "The conformal battery is a centralized power source for all the things that a soldier needs to carry -- GPS, smartphone, radio, other electronics, (and) eliminate the extra batteries for each individual item." "No longer do you need to carry extra radio or GPS batteries," he continued. "You only need to carry spares for the conformal battery."

The target is a battery that can last for 72 hours of continuous operation, but the release doesn’t say how much each battery weighs or costs.

In addition to being too bulky, the Army's conventional batteries can no longer handle the power demands for worn devices such as Nett Warrior, a handheld tool that provides situational awareness and mission command capabilities, Mapes said. These networked systems are always sending and receiving data, similar to leaving a cell phone on during a flight. They continuously search for a signal, which rapidly drains the battery.

"You have a power burden that has never before been imposed upon soldiers, particularly the small-unit leaders,” Mapes said. “The traditional power strategy for the individual warfighter was fast becoming impractical and irrelevant."