Wanted: More Batteries for Defence

Batteries come in many shapes and sizes: big and small; heavy and lightweight; rectangular and round. Whatever the form, they share one key trait: these devices have quietly become one of the most important technology enablers of the 21st century. Hardly a week goes by without a claim of a breakthrough set to reshape the world of energy, or a reminder of their strategic place in the evolving balance of power.

While the importance of batteries for civilian use is widely recognised, their military role is less understood. As Allied defence spending increases, the demand for batteries is expected to follow suit. This creates an opportunity to bolster supply chains, build up domestic production and push innovation forward – all while making warfighting capabilities stronger.

A Relentless Pace of Innovation

First invented in 19th century, batteries have gone a long way from being a niche technology, traditionally associated with remote controls and Walkman players. In recent years, they have assumed a much greater role, particularly in areas like electric vehicles and energy storage. Going forward, batteries are expected to provide the bedrock of an increasingly electrified economy.

The ascent of batteries has been nothing short of remarkable over the past decade. In 2015, the global lithium battery manufacturing capacity stood at around 60 gigawatt hours (GWh). By 2024, it had surged to 3 terawatt hours (TWh) – a whopping 50-fold increase. While most of this capacity remains concentrated in Asia, other regions are slowly catching up. The International Energy Agency estimates that if announced projects come online, global capacity could triple within five years.

Rapidly decreasing costs and quality improvements are driving this battery boom. According to the Rocky Mountain Institute (RMI), battery costs have fallen by a dramatic 99% over the past 30 years. Meanwhile, the energy density – the amount of energy a battery cell can store – has increased fivefold, making top-tier cells cheaper and more efficient than ever before.

This has triggered what some call the battery ‘domino effect.’ As batteries get cheaper and more capable, they unlock new business models and use cases, allowing the technology to go from one sector to the next. That, in turn, attracts more investment and leads to further innovation. The RMI estimates that each doubling of battery deployments has cut costs by 19% and boosted energy density by 7%.

Looking ahead, this trend shows no signs of slowing down. Costs are projected to continue declining, while energy density is set to rise. In fact, battery density might quickly accelerate in the 2030s due to technological breakthroughs, including advanced chemistries and solid-state batteries.

Batteries on the Battlefield

While battery use is well understood in a civilian context, their defence applications often fly under the radar. Yet batteries play a crucial role across all four physical military domains: land, sea, air and space.

On land, batteries enable everything from portable devices – radios, night-vision goggles, GPS units – to microgrids and directed energy weapons. At sea, they are used not only in submarines, but also in surface ships, torpedoes and autonomous underwater vehicles (AUVs). In the air, batteries are found in missiles, unmanned aerial vehicles (UAVs) and even fighter jets. And in space, they work alongside solar panels to power military satellites, enabling surveillance, positioning and communications.

Even in cyberspace – the so-called fifth domain – batteries are used in COMSEC devices and play an important, if indirect, role by providing backup power to data centres and supercomputers.

Of course, there is no one-size-fits-all battery suitable for all these different applications. Battery types and chemistries vary depending on performance requirements. These include: energy and power density, longevity and safety, just to name a few.

For example, single-use thermal batteries, commonly found in missiles such as the Patriot or guided munitions, share little in common with the multi-use batteries used in F-35 fighter jets. Meanwhile, the relatively heavy lithium-iron phosphate batteries, often used in microgrids for energy storage, are ill suited for portable devices, where every gram matters and very-high energy density is key.

Military batteries also face more extreme operational demands than civilian ones. They must endure heat, cold, shock and vibration. All this while delivering constant performance.

Yet despite these differences, there is significant overlap between civilian and military battery supply chains. That is because most suppliers to the defence sector also produce for the consumer market. This allows the military benefit from learning curves and economies of scale, which are fuelling advances in the civilian domain. Going forward, as battery technologies continue to improve, more high-performance batteries will find their way into military applications – potentially reshaping the way future wars are fought.

More Batteries, More Urgency

At the 2025 NATO Summit in The Hague, Allies made a commitment to invest 5% of GDP in defence by 2035. Of that, up to 1.5% can be allocated to initiatives that, inter alia, ‘innovate and strengthen the defence industrial base.’ The overall decision to ramp up defence spending will have a transformative effect. More funding will flow into hardware and that will inevitably push battery demand forward.

While it is too early to speculate how many batteries will be needed – or what kinds – it is safe to say that demand will be huge.

Take UAVs, for example. Russia’s unprovoked full-scale war against Ukraine has provided critical lessons in modern warfare. Chief of them: UAVs have transformed the conduct of war. According to some estimates, airborne UAV attacks could have accounted for as much as 70% of frontline casualties on both sides. Though it is difficult to say how future conflicts will be waged, there is little doubt that UAVs will play an integral role in future multi-domain operations.

Unsurprisingly, this has led to a flurry of announcements across Europe and North America about plans to scale the manufacturing of UAVs. Ukraine alone has said that it plans to procure some 4.5 million first-person-view (FPV) UAVs in 2025, mostly from domestic suppliers. Crucially, each of these UAVs will need a battery – and millions more will be needed across the Euro-Atlantic area.

At first glance, this battery demand for UAVs may seem trivial. But the reality is more complex given China’s dominance over the battery industry. By some estimates, Beijing controls some 70-90% of the battery market, across all stages of the value chain – from mineral extraction, processing to the manufacturing of cells.

China’s strong presence also extends to the commercial UAV market, including the production of lithium polymer batteries that power most FPV UAVs. As a result, if no remedial steps are taken, there is a risk that certain types of military UAVs built in Europe and North America could, in the coming years, end up running on batteries or battery components from China.

This could raise at least two security concerns. First, when it comes to defence enablers such as batteries, it is risky to rely on a single supplier. If anything, the COVID-19 pandemic has demonstrated the importance of diversification. Second, Beijing has already shown a willingness to weaponise trade. In 2024, it banned exports of critical materials like antimony, gallium and germanium to the United States. This year it placed export restrictions on battery technologies and limited the flow of critical materials to defence manufacturers.

More generally, there is also the concern about overreliance. The more critical systems depend on Chinese components, the greater the potential risks for the Alliance’s technological and energy independence.

Seizing the Moment

Greater defence spending offers a chance to drive innovation, bolster domestic battery industries and strengthen military capabilities. But as the Northvolt bankruptcy demonstrated, this is easier said than done. Building a battery ecosystem requires strong policy support, robust public-private partnerships, close collaboration with academia, a tolerance for risk and – above all – funding, lots of it.

The civilian sector will take the lead in battery innovation – simply because its market size dwarfs the military’s. But the defence sector can still play an important supporting role. Four concrete steps could help.

First, clearly communicate defence battery needs. A weak demand signal and complex specifications makes it tough for the defence sector to secure high-performance, low-cost batteries. From a supplier’s perspective, it is difficult to justify large-scale investment in a market seen as small or risky. This issue could be addressed by aggregating demand and procurement, simplifying and clarifying requirements and working toward multinational agreements on form factors used in defence applications. First steps to implement these actions are being taken by facilitating multinational cooperation between Allies under the umbrella of NATO’s High Visibility Projects (HVPs).

Second, support early-stage battery start-ups. DIANA, the Defence Innovation Accelerator for the North Atlantic, offers a good model for accelerating dual-use innovation, including in batteries. It supports start-ups not just with funding, but also with mentorship, access to testing facilities and connections to end-users and investors.

Third, test and validate new battery solutions. NATO’s recently announced Rapid Adoption Action Plan can support efforts to experiment with emerging battery solutions and accelerate their integration. Multinational exercises, such as the Capable Logisticians series, also help. Field trials can build confidence, improve interoperability and speed up adoption.

Fourth, help address shortfalls and vulnerabilities by scaling the most promising battery technologies. Moving from pilot projects to mass production is costly and high-risk, especially when early outputs remain low and the operational costs remain high. Public financing can help bridge the ‘valley of death’ – whether from the 1.5% of GDP allocated to defence- and security-related investments, or through entities like the NATO Innovation Fund.

Conclusion

Ukraine has demonstrated the critical role of technology innovation and adoption in strengthening its defence. At the NATO Summit in June, the Alliance committed to step up its defence investment and innovation. For many defence applications, batteries are central to technology advancement. By acknowledging the existing gaps and by investing in advanced battery solutions, Allies can hit two birds with one stone – reducing supply chain vulnerabilities and ensuring their competitive edge for tomorrow.

The views expressed in this article are the author’s own, are contributed in a purely personal capacity, and may not represent those of NATO.

© Lukas Trakimavicius, 2025, published by RUSI with permission of the authors.

The views expressed in this Commentary are the authors', and do not represent those of RUSI or any other institution.

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