Nickel-cadmium (NiCd) and nickel-metal hydride (NiMH) batteries have long been integral to military operations due to their reliability, ruggedness, and ability to perform under extreme conditions. These nickel-based chemistries are particularly valued in mission-critical applications where failure is not an option, such as military communications and unmanned aerial vehicles (UAVs). Their ability to withstand harsh environments, including extreme temperatures, mechanical stress, and prolonged storage, makes them indispensable in defense applications.

Military communications systems demand power sources that can operate reliably in diverse and challenging environments. NiCd and NiMH batteries are commonly used in portable radios, satellite communication devices, and field equipment. Their robust construction ensures they can endure shocks, vibrations, and rough handling during transport and deployment. Unlike lithium-ion batteries, which may degrade or become unstable under extreme temperatures, nickel-based batteries maintain functionality in both arctic cold and desert heat. For example, NiCd batteries can operate in temperatures as low as -40°C and as high as 60°C, making them suitable for global military operations. Their low self-discharge rates also allow for long-term storage without significant loss of charge, a critical feature for equipment that may remain unused for extended periods before deployment.

In UAVs, power reliability directly impacts mission success. NiCd and NiMH batteries are often chosen for small to medium-sized drones due to their ability to deliver consistent power under high discharge rates. These batteries provide the necessary energy density and cycle life for reconnaissance, surveillance, and short-range tactical missions. Their resistance to voltage depression, a common issue in rechargeable batteries subjected to partial discharge cycles, ensures stable performance over repeated use. Additionally, NiCd batteries are less prone to thermal runaway compared to lithium-based alternatives, reducing the risk of catastrophic failure during flight operations. This safety advantage is crucial in military UAVs, where battery failure could compromise sensitive missions or result in the loss of expensive equipment.

The ruggedness of nickel-based batteries extends beyond temperature tolerance. Military-grade NiCd and NiMH cells are designed with reinforced casings to protect against physical damage from impacts or ballistic threats. Sealed designs prevent electrolyte leakage, even under high mechanical stress, ensuring safe operation in combat scenarios. These batteries are also resistant to electromagnetic interference (EMI), a critical requirement for electronic warfare systems where signal integrity is paramount. Their ability to function in high-vibration environments, such as those encountered in armored vehicles or aircraft, further underscores their suitability for defense applications.

Extreme-temperature performance is a defining characteristic of nickel-based military batteries. In cold climates, lithium-ion batteries suffer from reduced capacity and increased internal resistance, leading to voltage drops under load. NiCd batteries, in contrast, exhibit superior cold-cranking ability, delivering high currents even in sub-zero conditions. This trait is vital for starting engines in military vehicles or powering equipment in arctic operations. At high temperatures, NiMH batteries demonstrate better thermal stability than many alternatives, with slower degradation rates over time. Their ability to endure thermal cycling—repeated exposure to extreme heat and cold—makes them ideal for equipment subjected to fluctuating environmental conditions.

Military specifications often require batteries to meet stringent standards for shock, vibration, and ingress protection. Nickel-based batteries are routinely tested under MIL-STD-810G, a U.S. Department of Defense standard that simulates harsh environmental conditions. These tests include drop tests from significant heights, exposure to salt fog, and immersion in water, all of which NiCd and NiMH batteries must pass to qualify for military use. Their compliance with such rigorous standards ensures they can withstand the demands of battlefield deployment.

Another advantage of nickel-based batteries in military applications is their ease of maintenance and long service life. NiCd batteries, in particular, are known for their ability to recover from deep discharge conditions, a feature that enhances their reliability in field operations. They can endure thousands of charge-discharge cycles with minimal capacity loss, reducing the need for frequent replacements. This longevity is especially valuable in remote or austere environments where logistics support is limited. NiMH batteries, while slightly less durable than NiCd in deep-cycle applications, offer higher energy density, making them suitable for missions requiring extended runtime without recharging.

In terms of logistics, the widespread use of nickel-based batteries across military platforms simplifies supply chain management. Standardized form factors and voltages allow for interoperability between different devices, reducing the need for specialized power sources. This commonality is particularly advantageous in joint operations where multiple branches of the military may rely on the same battery types. Additionally, the mature manufacturing processes for NiCd and NiMH batteries ensure consistent quality and availability, minimizing the risk of supply shortages during prolonged conflicts.

Environmental considerations also play a role in the military's continued use of nickel-based batteries. While cadmium, a key component of NiCd batteries, is toxic, modern sealed designs prevent leakage and allow for safe disposal or recycling. The military has established protocols for handling and recycling these batteries to mitigate environmental impact. NiMH batteries, which do not contain cadmium, offer a more environmentally friendly alternative while retaining many of the performance benefits of NiCd chemistries.

Despite the growing popularity of lithium-ion batteries in consumer and commercial applications, nickel-based batteries remain a cornerstone of military power systems. Their proven track record in extreme conditions, combined with their safety and reliability, ensures their continued relevance in defense technology. As military operations increasingly rely on electronic systems for communication, surveillance, and unmanned missions, the demand for rugged, high-performance power sources like NiCd and NiMH batteries will persist. Their ability to meet the rigorous demands of military use underscores their enduring value in national defense.