Portable power storage for the dismounted soldier

The dismounted soldier today relies on an increasingly diverse array of personal equipment, electronic devices and sensors, most of which require a constant power supply for effective operation. That means already over-burdened warfighters must carry enough stored power to perform their mission.

Electric power and dismounted power budgets are crucial for the future of warfare and electrification of the battlefield across all domains. For the dismounted soldier, equipped as never before with electronics, optical and communications equipment, powered sights, night vision goggles and more, most of which requires a constant, steady and managed power supply. This typically means batteries, which have to be carried in quantities appropriate for any mission.

According to Steve Heaword, Technical Director at Crib Gogh and part of the UK MoD’s Jungle Warfare Programme, “Battery burden depends on the operation type and the power budget you need for that operation, and is something that is mission critical to get right, considering that burden can account for as much as 25% of a soldier’s equipment carry. Reducing it is, therefore, a major goal for military and industry vendors, alike, with new technologies, battery chemistries, fuel cells, centralised power units and power management all playing a part in that process. The individual soldier is depending on that burden being lowered. The technologies need to have more AI in them, so they are activated when needed. This would then reduce the cognitive burden that is already impaired by the weight and thermal burdens that the dismount already suffers.”

Companies across the defence industry, including Bren-Tronics, Denchi, Enersys, Epsilor, Lincad, Saft, and many others, are pioneering developments to meet the increasing demands of the military user and to lower the battery burden. ESD spoke with a couple of these companies for some qualified, up-to-data views on man-portable power storage solutions and developments.

Modern soldier, modern demands

Weighing into the man-portable power storage discussion, Peter Slade, joint MD at Lincad, a UK designer and manufacturer of battery and charger technology, told ESD, “Whilst some man-worn equipment can be powered by either primary or secondary batteries, much of the equipment requires significantly-sized battery packs, which are not available as commercial off-the-shelf items.”

Slade said that to avoid battery waste and the logistical burden of supplying large volumes of primary batteries, secondary batteries are used. He added, “The ability to recharge is a fundamental consideration and increasing the charging options available improves the flexibility of military operations. Whilst most batteries tend to be swapped out and recharged back at base in a barracks environment using an AC/DC charger, batteries may also be charged by DC sources directly, such as from a DC vehicle source, or from renewable sources, such as solar PV, or a micro wind turbine.”

In this regard, Slade said that the company’s Harvester system provides exactly this capability to harvest energy from any DC input, and allows the charging of lithium-ion power systems (LIPS), and other battery types. This offering is a flexible solution to mobile power management where reliability, portability and ease of use are critical.

On battery chemistry, Slade said that, “Lithium-ion (Li-ion) tends to be the chemistry of choice for most applications using secondary batteries, as it offers several advantages, including: high energy density, long lifecycle, low self-discharge rate, quick charging, versatility, no memory effect and low maintenance.” He added that several Li-ion battery types are available, each with its own specific characteristics and advantages, with Lincad most commonly using lithium nickel cobalt manganese oxide (NMC), which, he said, offered a good compromise between energy density and power capability. According to Slade, “Most NMC cells that we employ are in a cylindrical format, either 18650s or 21700s, [Note: the numbering system referring to cell dimensions]. More recently, we’ve been using lithium iron phosphate (LFP) batteries, which are known for their long lifecycle, high thermal stability and enhanced safety.”

As for the immediate future for man-portable energy storage, Slade added that this would continue to rely on secondary battery technology. “New developments continue to move at pace, and we are already seeing new chemistries being employed, such as sodium-ion, solid-state lithium-ion and lithium-sulphur; longer term, the energy outlook may be very different compared to today.”

He suggested that whilst society moves away from fossil fuels towards renewable energy resources and energy storage technologies such as batteries, liquid fuels will still have a significant role to play in the energy mix.

“Further into the future,” Slade continued, “There will likely be revolutionary energy technologies that seem hard to comprehend now. Much research is taking place on the development of small-scale nuclear technologies, for example, and, whilst this may currently feel like the stuff of science fiction, who knows where technology may be in 50-, or 100-years’ time.”

Amongst the range of battery products Lincad designs and makes for wearable soldier equipment, are large volumes of non-rechargeable (primary) battery products for military use (such as AAs and AAAs), though it is the rechargeable (secondary) battery types that the company says it specialises in. According to Slade, Lincad’s batteries range in size from relatively simple, single-battery solutions, such as that used on Thales’ SquadNet radio, to their more modestly-sized LIPS range of ruggedised, intelligent batteries.

At the larger end of the man-portable scale, Slade told ESD that the company also produces various battery systems that fall within the uninterruptible power supply system category, providing battery back-up power during power outages and protecting against voltage fluctuations and power spikes.

Man-portable, wearable, hybrid

Reinforcing such views and offering others, a senior spokesperson from Bren-Tronics, which produces primary and secondary rechargeable batteries, chargers and complete energy storage systems, told ESD, “recent years have witnessed significant breakthroughs in energy storage technologies, enhancing the capacity and efficiency of man-portable power systems, with lithium-ion batteries in particular becoming the go-to choice for their high-energy density, longer lifecycle, and reduced weight, all of which offers a lightweight, yet potent, energy source for individuals on the move.”

While this view echoes the lithium-ion sentiments of their industry peers at Lincad, the Bren-Tronics spokesperson noted that beyond lithium-ion, emerging technologies such as solid-state batteries and advanced fuel cells are gaining attention for their potential to further improve energy density, safety, and environmental impact, adding, “As these technologies mature, man-portable power systems will likely see even more compact and powerful energy solutions.”

In the meantime, Bren-Tronics stated that the integration of intelligent power management systems, which leverage algorithms and sensors to optimise energy consumption, monitor battery health, and predict usage patterns, is “transforming the way portable power is used”, adding, “By intelligently managing power resources, users can extend the operational life of their devices, reduce the need for frequent recharging, and enhance overall mission effectiveness.”

Furthermore, the company spokesperson added that the continuing need for versatile charging solutions in the field remains, and has led to the development of multi-modal charging systems, which can harvest energy from various sources, including solar, wind, and kinetic energy. Such solutions ensure that individuals, including special operations forces in remote or dynamic environments, do not have to rely on grid-based charging methods or resupply, and can recharge their secondary batteries using these multi-modal solutions.

On the subject of conformal and wearable battery technologies, Bren-Tronics spoke briefly of recent advances revolutionising how soldiers carry and use power in the field: “Conformal batteries are designed to seamlessly integrate into equipment, reducing the need for bulky external power sources, which not only improves mobility, but also enhances the overall ergonomic design of military gear. Wearable batteries take this concept a step further, providing power solutions that can be integrated into clothing, or worn as accessories”.

Before speaking about the company’s own products, mention was given to the emergence of hybrid solutions that combine both storage and power-generation abilities in the same system, something which meets the needs of highly mobile and ‘independent’ operatives in scenarios way off grid: “Hybrid man-portable power systems combine efficient energy storage with versatile power generation, enabling users to replenish their energy reserves in remote or dynamic environments.”

As for the company’s portfolio, the spokesperson highlighted its BB-2590 rechargeable lithium-ion battery, as “versatile and durable” in the man-portable power storage domain, with a “high energy density that allows it to store a substantial amount of energy in a compact and lightweight form factor”. The unit also has sophisticated safety features, which include protection against overcharging, over-discharging, and short circuits. The former relates to its high number of charge-discharge cycles, which, amongst other things, reduce the need for frequent replacements while its rugged design sees the battery built to withstand extremes of temperature, vibration and mechanical shock, suiting it to the most demanding military operations.

Another Bren-Tronics’ solution highlighted was the conformal wearable battery (CWB), which, according to the company spokesperson, “has a conformal design, enabling it to be seamlessly integrated into a user’s gear, which reduces the burden of carrying external power sources.”. The spokesperson added, “The CWB is customisable, so it can be configured and adapted to specific user needs, whether powering communication devices, sensors, or other equipment. The battery also features hot-swappable modules, enabling users to replace depleted modules without interrupting power to connected devices, thereby ensuring continuous power availability in the field.”

The company stressed that the CWB uses smart battery management technology, to optimise energy usage, monitor performance, and provide information feedback about the system to the user.

Final thoughts

Future warfare is an increasingly tech-dependent, power-hungry affair, with the individual warfighter in danger of becoming overloaded, both physically and mentally, by high-tech devices, sensors, communications and electronics, together with the stored energy systems and batteries required to power them all. While major advances already certainly improve the curse of the battery burden, continued progress in man-portable stored power will help ensure that the valuable asset – namely the individual soldier – will not become an overwhelmed beast of burden.

Tim Guest