The vision for the future soldier is to be combat effective and also highly mobile, adaptive, networked, sustainable with total battle space situation awareness and information assurance. Therefore, he is equipped with night- vision goggles, radios, smartphones, GPS, infrared sights, a laptop as well as batteries to power them. Some of the missions the soldiers perform can take weeks, rather than days, without any ability to recharge; therefore he carries many spare batteries.
Powering all of this equipment is vital for success on the battlefield, however, they also add up to the weight, an infantry platoon currently carries about 700 pounds of batteries (17 pounds per soldier) for a 72-hour mission, according to the Army. Take, for example, the PRC-154 Rifleman Radio. The radio has a battery life of seven hours, and each battery weighs 0.8lb (0.36kg), so a 72-hour mission requires 8.8lb (3.99kg) of batteries just for that one radio.
Sometimes soldier carry seven types of batteries weighing up to 16 pounds for a 72-hour mission. All that weight slows down soldiers on foot, tethers them to constant resupply, and contributes to muscular and skeletal injuries caused by excessively heavy packs. However, it is important to consider ergonomics that go beyond weight, e.g. balancing the placement of batteries over the human body over the chest armor in addition to hips.
Resupplying this number of batteries effectively is a logistical nightmare, especially for fragile military infrastructures. In addition it is expensive, according to the U.S. Army Research Laboratory; a typical infantry battalion spends more than $150,000 on batteries alone each year, the second-highest expense next to munitions. Such high demand of power may not be fulfilled by batteries alone.
The major military organizations in the world are devising various ways for meeting enhanced power requirements, while also reducing the logistical load thereby enhancing soldier’s agility on the battlefield. Some of the solutions are developing smaller, lighter, cost-effective power sources, switching to renewable energy options, flexible solar panels, wearable energy solutions, nuclear batteries, low power electronics, battery and power management.
Another attractive emerging solution is that of Energy harvesting technology that is capable of replacing or supplementing a battery with the development of various mobile electronics. In environments where stable electrical supply is not possible, energy harvesting technology can guarantee an increased leisure and safety for human beings.
Developing better batteries
Rechargeable lithium batteries are now becoming more viable as power densities have increased and costs reduced and they can be recharged from a variety of power sources, including portable and wearable solar panels and other energy-harvesting sources.
Military-grade primary lithium batteries specified to meet temperature extremes are becoming available. They are proving particularly useful in the increasing number of portable military electronic systems now deployed, such as night vision equipment, emergency locator beacons and GPS-based trackers, as well as portable tactical computers and communications systems.
“Right now the next focus for us is for lithium-sulfur and lithium-air chemistries,” Michael Brundage, chief of the tactical power branch at the Army’s Communications-Electronics Research, Development and Engineering Center (CERDEC) said. “You’re always going to be dealing with lithium because … it’s the lightest” metal and “we have to focus on maintaining that lowest weight solution that we can.” Although the energy density of traditional batteries is improving, it is not keeping up with demand for more power, officials said.
Power surge: developing the next generation of nuclear batteries
One of the technologies that the military is looking at for soldier power is betavoltaics. Betavoltaic sources generate power from beta particles emitted by radioactive materials. “They can last a long time [and] you can make them very small,” said Tom Adams, an engineer at Naval Surface Warfare Center Crane division, which has contributed to Army-applicable R&D. “A betavoltaic incorporated into a flight data locator could signal to search teams for years instead of months.”
“Several teams are pursuing nuclear battery research at the University of Missouri,” says Patrick J Pinhero, professor in the chemical engineering department and the nuclear engineering programme. “Much of this work is focused on pushing the frontiers of nuclear battery technology by employing power sources using alpha or beta-particle decay based on a radioactive isotope that can be produced, separated and refined at the University of Missouri Research Reactor (MURR).”
“Our idea is to focus on tritium, an isotope of hydrogen that possesses two neutrons in addition to the single proton and electron inherent to its common hydrogen form.” Tritium is a radioactive isotope that reduces its overall population by one-half every 12.32 years by the pure emission of a beta-particle, which is essentially an electron, an advantage over many other solutions, which produce harmful gamma radiation. There are other qualities of tritium that are appealing: it is the third lightest isotope, it possesses properties and reactivity similar to hydrogen, its path for production is very well-known and simple, and its hazards are well-known.
“The first betavoltaic batteries were developed during the 1950s and the basic design – an electron emitter coupled to a collector – remains the same to this day,” says Alan K Wertsching, senior staff scientist formerly with the Idaho National Laboratory Commercially available betavoltaic chipsets are low voltage and amp products for niche markets, such as the military, and in order to produce greater performance from betavoltaics, we looked at producing layered stacked arrays as a means of building to the needs of potential customers.
“Unfortunately, traditional materials were unsuitable for large stacked arrays because the mass and volume of a final battery would be excessive. Much thinner, lighter emitters and collectors were needed for an array design.” “Recent advances in the material science of graphene have yet to be incorporated into betavoltaic architecture, which, when incorporated into thin stacked betavoltaic arrays, would allow greater overall performance and wider utilization,” he further says.
“There are many situations where betavoltaic power generation can provide superior performance over traditional chemical batteries and solar cell systems, including poor light conditions, physical extremes, inaccessible locations, disaster areas and irradiated locations.”
DARPA’s Propane generator to Charge Batteries for War
With the support of DARPA’s Trans App program, a team of engineers from Ultra Electronics have built a lightweight, 350-watt propane generator that’s capable of charging batteries in the field.The developed generator is far quieter than gasoline-powered generator, thus reducing the risk of giving away their position to their enemies. 3000 US soldiers were killed or wounded from 2003 to 2007 during attacks on fuel and water convoys to Iraq and Afghanistan.
The propane generator weighs just 11 pounds, and the tank weighs an extra 20, has the potential to replace 100 batteries weighing over three pounds each thus allowing soldiers to carry in a few batteries and recharge them on the fly.
Fuel cells for soldiers
Fuel cells are also designed to provide power to future soldiers. Thampan modeled, designed, and developed a Soldier wearable power system that can cut a Soldier’s weight burden by up to four times. He did this by using a fuel cell membrane made of Aluminum hydride, or AlH3, which provides a better energy density than the common Li-on battery used today.”Now that these solutions have increased energy density systems, you can go out on longer missions and keep the weight manageable,” Thampan said.
“Today’s challenge for our dismounted infantry Soldier is basically weight, so we have situations where some Soldiers are carrying in excess of 100 pounds. Ideally you want to be at a thirty percent body weight, so you want to carry like 30 pounds,” Dr. Tony Thampan, a chemical engineer in the Army’s Communications-Electronics Research, Development and Engineering Center, or CERDEC, said. “Before they would just limit the missions, and that takes away capability.”
The wearable power system powers individual Soldier devices or all of a Soldier’s ensemble devices — such as worn radios and end user devices — through a power distribution system. It consists of a power unit with an internal starting battery, fuel gauge and fuel cartridges.The system is flexible and can be worn in a pouch on the side of a Soldier’s vest. It has passed government ballistic testing requirements and is rated safe for Soldier’s to wear.
(“Advent”) and its subsidiary, UltraCell, announced in March 2021 that UltraCell’s 50 W Reformed Methanol Wearable Fuel Cell Power System (“Honey Badger”) has been selected by the U.S. Department of Defense’s National Defense Center for Energy and Environment (“NDCEE”) to take part in its demonstration/validation program for 2021. Some of the many features of the Honey Badger 50 system include: Fueled by a NSN 6850-00-926-2275 Cleaning Compound, Windshield (CCW) which is ~70% methanol and water; Its material is already in the arsenal with proven supply chain and minimal safety concerns, compared to JP8 fuel; Compared to generators, the Honey Badger is very quiet at only 40-45 dBA vs. 90+ dBA.
In June 2021, Advent Technologies subsidiary UltraCell was awarded a contract to advance its 50W Reformed Methanol Wearable Fuel Cell Power System (Honey Badger) for US Army integration. SAFCell and UltraCell have commenced the design and fabrication of a 50 watt, propane-fueled power unit based on the use of SAFCell’s proprietary Solid Acid Fuel Cell stacks in UltraCell’s world-leading military portable power systems. This first-of- its-kind ultra-light power unit will reduce by half the total battery weight burden on the modern soldier, up to 44 pounds for a three-day mission, enabling them to carry more mission critical equipment and ammunition.
Its small size and virtually silent operation makes it inconspicuous for highly remote or covert surveillance applications. It can run continuously off the grid for up to two weeks with a single BBQ propane fuel canister. Because it’s a solid state fuel cell with minimal moving parts, it requires minimal trips for servicing. Our system is ideally suited for a wide variety of higher-power electronic applications including radio and satellite communication gear, remote or mobile surveillance systems, soldier worn anti-IED and mine devices, laptop computers, and battery charging.
Ultralife Corp. and EaglePitcher Technologies Inc. have developed lithium carbon mono-fluoride manganese dioxide “hybrid” batteries, which utilize the advantages of each type of chemistry to enhance performance when it comes to capacity, energy density, discharge rate, shelf life and temperature range functionality. The technology will lighten troops’ loads because fewer batteries will be required to perform the mission, officials and members of industry said.
Phil Robinson, vice president of defense power systems at Protonex, a Massachusetts-based fuel cell company, said there are several potential “double hybrid” system combinations, including battery-battery, battery-lithium-ion capacitor and fuel cell-battery. “Triple hybrid” systems are also in the works, he said.
UK Dstl’s ‘Solar Soldier’
The UK’s Defence Science and Technology Laboratory (Dstl), in 2011 under project called ‘Solar Soldier’, looked to use a combination of wearable solar photovoltaic cells and thermoelectric devices to provide a ’round-the-clock’ power supply for soldiers. The study found that solar panels have advantages under sunny conditions and for non critical equipments; however they have limited advantages in short missions as the added weight of associated charger and cables, outweighed the benefits, as there is little time to harness such energy. However for mission critical equipment there is little justification for reducing number of spare batteries, according to Dstl spokesman while speaking to Army-technology.com.
Wearable energy solutions
According to research conducted by Markets and Markets (Northbrook, IL), the military wearables market is projected to grow from $4.2 billion in 2019 to $6.4 billion by 2025. That’s a 7.2% growth from 2019 in six short years. Soldier modernization programs that increase soldier coordination, rising asymmetric warfare, and potential geopolitical conflicts are all factors fueling the growth of this market.
Several companies are working on wearables that integrate communication, sensors and energy sources. Kinetic energy would create energy, the clothing would store it and then recharge devices as needed. While the concept sounds great, unfortunately the reality is that this solution is still off in the future.
Conformal wearable battery (CWB)
The CWB provides solutions to two core challenges faced by the overloaded soldier: weight and power source. Today’s CWB products solve these challenges by offering a high-powered but ergonomic battery that soldiers can comfortably wear next to their chest.
The conformal batteries are virtually invisible and transparent to the soldier, while providing efficient space utilization by allowing the soldier to hang his magazine, grenades or flashlight over the battery.US Army engineers have developed conformal wearable battery (CWB) that is flexible enough to be integrated into body armor and and serves as a single source of power for all worn electronic devices. The CWB provides more power, enabling 72 hours of continuous operation thus reduces the need for battery recharging and spares.
To facilitate access and energy distribution for troops on the move, the Army and industry are working on “wearable” power generation devices that could be attached to a soldier’s vest or body armor. Army Maj. Ronald Schow, assistant program manager for soldier power at program executive office soldier said a conformable wearable battery (CWB) and power management system have been developed to simplify things for soldiers on the go.
“Our power distribution system will triple charge all those other batteries that are on the ends of those radios, so all the soldier has to worry about is managing his conformable wearable battery in order to meet his mission requirements,” he said. The CWB and the connected power distribution system would result in a 17 percent net weight reduction for troops because they would need to carry fewer batteries, Schow said.
In the near future, soldiers will be carrying CWBs with a higher energy density than current models, However, the rise of higher-capacity cells raises another consideration, and that centers on preserving the safety of the soldiers. 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.
Mini solar cells could transform wearable energy
Solar energy is currently being harvested in the battlefield. Solar blankets and panels have been integrated into platoon set ups, which can produce and store power for recharging. However, the limitation here is that soldiers need to stop and recharge —an almost impossible task during a mission. Current fielded solar technology proves good for backup, and the power management introduced with the technology allows soldiers to transfer power from partially depleted disposable batteries to rechargeable batteries and devices. This helps get the most out of the power supplies on hand. But solar technology doesn’t completely deliver the power and agility required.
Nottingham Trent University has developed a way to embed miniaturised solar cells into yarn that can then be knitted and woven into textiles. The researchers found that an array of 200 mini solar cells embedded into a 5cm² section of fabric can generate up to 80 milliwatts of power, enough to charge a Fitbit wearable device or a basic mobile phone. Scaled up to 2,000 cells, the researchers say the system could charge a modern smartphone.
The project makes use of solar cells that measure 3mm long and 1.5mm wide. These flea-sized powerhouses are too small to be felt by a wearer, and each cell is laminated in a waterproof resin to allow them to survive the laundry process unharmed.
“The clothing would look and behave like any other textile, but within the fibres would be a network of miniaturised cells which are creating electricity,” said project lead Professor Tilak Dias of NTU’s School of Art & Design. “This could do away with the need to plug items into wall sockets and reduce the demand on the grid while cutting carbon emissions. The electrical power demand for smart e-textiles has always been its Achilles heel and this technology will allow people to use smart textiles while on the move.”
“With the availability of miniaturised solar cells we can generate power in a range of new ways, by utilising things like clothing, fashion accessories, textiles and more,” said NTU researcher Achala Satharasinghe, who developed the proof-of-concept textile square. “It will allow mobile devices to be charged in environmentally friendly ways which are more convenient for consumers than ever before.”
U.S. Military selects ASTL’s MilPak(TM) E as finalist for R&D award
Ascent Solar Technologies, Inc. ASTI’s newest rugged fully-integrated photovoltaic power solution, the MilPak(TM) E, has met the MIL-STD-810G testing which includes, but not limited to, dropping onto concrete, blowing rain, temperate extremes and random vibration.
The MilPak(TM) E is a fully integrated mobile power solution that includes a foldable photovoltaic blanket with an attached waterproof battery case that houses a maximum peak power tracker, 86.5 watt hours of power storage with battery management circuitry, a 55 watt 24 volt power circuit, and two high-current USB circuits.
In keeping with the ruggedized requirements, all switchgear, protection circuit, and the 24V and USB connectors are all rated IP-67 or better, and the case is constructed from a military-grade plastic. Most important, the entire unit weighs in at less than 8.5 pounds (3.8 kg) which makes it extremely portable by military or other users
U.S. Marine Corps’s Marine Austere Patrolling System or MAPS
The U.S. Marine Corps Expeditionary Energy Office (E2O), has developed an ultra lightweight vest, Marine Austere Patrolling System, or MAPS, consisting mainly of a solar- energy harvesting and storage system and water-purification unitIt uses ultra light weight 9 x 14–inch photovoltaic panel and a rechargeable battery, weighing less than 3 pounds, upto 20 pounds less than the batteries that soldier now carries.
The panel works, whether it’s stashed in a transparent sleeve on the vest or taken out for maximum exposure to the sun. An additional pack can be swapped in to feed rechargeable AA batteries, which power weapon-mounted devices such as night-vision scopes. However in extreme cold the water-purification unit freezes and the batteries fail to hold a charge, and in heavy shade the panels don’t operate, New solutions are being developed like adding power-generating knee braces to provide electricity in the absence of sunlight. Over the next two years MAPS will undergo bulletproofing and joint Army– Marines testing to prepare it for use in battle.Recent projects have looked to introduce photovoltaic solar cells onto the soldier’s personal kit and uniform to improve soldiers’ agility on the battlefield while meeting the demands of an increased power burden stemming from new networked electronic devices providing situational awareness and mission command capabilities.
A recent solar technology breakthrough reported in March 2022 from UK scientists brings “wearable solar” one step closer to commercial production and could greatly expand the amount of solar power generated by weaving the microscopic technology into daily living.
According to developers, the solar cell is “a hundred times thinner than a human hair” and “could be put on clothing to power wearable electronics, such as smart watches and Fitbits.” The breakthrough augments the cell’s efficiency and puts the technology on the brink of commercial manufacturability. Its developers aim to double its efficiency within five years. But even if they miss that target, they say they’re confident the cell will be commercially available within a decade.
The research, funded by the UK government, the European Research Council, and the European Union’s Horizon 202 programme, used complex computer modelling to increase the cell’s efficiency to 9%, from an average 1-2% a decade ago. The developers generated more power by applying an even, 50/50 spread of silver and bismuth atoms across the material to increase the amount of light the nanocrystals absorbed.
Because the cells are cheap to manufacture and thin and flexible enough to be unnoticeable, their development lays the groundwork for what the research team describes as a “winning by numbers” strategy, i newspaper says. “So while the power generated in a given area mightn’t be as high as a dedicated solar farm in the Sahara, the fact they are everywhere—and invisible—means we could still be capturing large amounts of energy with a vast ‘effective surface area,’” said Kavanagh.
Solar-Powered Wearable Batteries for Military and Civilian Uses
UCF scientist who has developed filaments that harvest and store the sun’s energy — and can be woven into textiles. According to the university’s website, Thomas’ research team developed filaments in the form of copper ribbons that are thin, flexible and lightweight. The ribbons have a solar cell on one side and energy-storing layers on the other. The team wove the ribbons into a square of yarn.
The proof-of-concept shows that the filaments could be laced throughout jackets or other outwear to harvest and store energy to power phones, personal health sensors, and other tech gadgets. It’s an advancement that overcomes the main shortcoming of solar cells: The energy they produce must flow into the power grid or be stored in a battery that limits their portability.
“A major application could be with our military,” Thomas said. “When you think about our soldiers in Iraq or Afghanistan, they’re walking in the sun. Some of them are carrying more than 30 pounds of batteries on their bodies. It is hard for the military to deliver batteries to these soldiers in this hostile environment. A garment like this can harvest and store energy at the same time if sunlight is available.”
Australian National University (ANU) SILVER solar cells
Australian National University (ANU), Centre for Sustainable Energy Systems has worked with Australia’s Defence Science and Technology Organisation (DSTO) to develop SLIVER solar cell modules for military use.These are extremely thin and flexible solar cells have high power-to-weight ratios and can be conformed to complex surfaces such as helmets. They have the same thickness of a sheet of paper or a human hair with energy to weight ratio of more than 200 watts per kilogram.
Wireless Power transfer for Soldiers
WPT has the unique potential to transform war fighting of the future and alleviate the battlefield battery burden for soldiersWireless power transfer (WPT) or wireless energy transmission is the transmission of electrical energy from a power source to a consuming device, without the use of discrete man-made conductors. WPT use wireless transmitter that uses any of time-varying electric, magnetic, or electromagnetic fields to convey energy to one or wore receivers, where it is converted back to an electrical current and then used.
Some recent examples are charging of Soldier’s central battery from vehicle seat back as they sit in vehicles, charging of handheld devices through vests, powering helmet-mounted devices through Soldier vest-to-helmet WPT, Soldier helmet-to-goggle WPT to power devices such as night vision, radio devices and defog optics.
Rise of the iSoldier
BAE Systems has created its Broadsword range of devices that revolve around a vest called Spine. Spine uses so-called e-textiles to wirelessly charge military equipment – and this energy use can be monitored using a smartphone app. Eight devices can be plugged in and charged at any one time, and the vest’s electrically conductive yarns can also be used to charge other gadgets wirelessly. BAE’s inductive seat charger transfers energy from a vehicle to the vest and all of this energy use can be monitored using a smartphone app.
Spine was developed by the London-based defence firm with Surrey-based Intelligent Textiles Design. It can power up and transfer data to and from equipment such as radios, cameras, smart helmets and torches, as well as smart weapons – effectively working as a portable hotspot.
Smart Energy, Power and Battery management
In military applications, battery and power management is also critical, partly because, unlike in many commercial applications, the batteries are often required to deliver specific power levels for short periods of time rather than a steady supply of power.
Reducing the energy consumption of our armed forces, or enhancing the Energy efficiency in the military is called smart energy. BrigGen Steve Anderson (Ret.), Chief of Logistics in Iraq, said that there is a direct relationship between energy efficiency and military effectiveness.” The aim of Smart Energy is to develop a self-sufficient, sustainable and modular energy system structure instilled with novel technologies using efficiently vital resources with increased combat effectiveness allowing troops to travel lighter and faster.
Sophiticated managers are designed to deliver the required power to any load from a variety of sources. These power managers also act as intelligent energy storage controllers, directing solar energy to battery charging for later use, or switching to alternative power sources if there is insufficient energy in the solar-based system. Similarly in the future advancements in wireless energy transfer will enable distribution of power amongst power sources, multimodal energy harvesters, and loads to occur wirelessly on the Soldier as a platform, so that all carried equipment will be powered and ready for operation at all times without thought to replacing individual equipment power sources.
Integrated Soldier Power and Data Systems (ISPDS): ISPDS is a technology that is available today to help lighten the load (both weight and power) and make power management a more controlled, agile routine for dismounted soldiers. An ISPDS enables simultaneous connectivity and control over data transmission and power management of multiple wearable devices. This technology makes sure that soldiers have unequaled situational awareness on the battlefield to make better decisions on-the-spot in combat and thereby increase mission efficacy.
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