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In modern warfare, the reliance on advanced electronics and portable devices has made power management a critical factor in ensuring mission success. From communications equipment and surveillance tools to wearable technology and autonomous systems, the demand for reliable, long-lasting, and secure power sources has never been greater. At the heart of this power management challenge lies the Battery Management System (BMS), a sophisticated electronic system that oversees the operation of rechargeable batteries. For military applications, BMSs must go beyond the capabilities of commercial systems, offering fault-tolerance and robust cybersecurity measures to meet the unique demands of the battlefield.
The Challenge of Military Power
The modern soldier is a highly equipped warrior, with an array of devices designed to enhance combat effectiveness, mobility, and situational awareness. This gear includes night-vision goggles, radios, smartphones, GPS systems, infrared sights, and laptops. Some of the missions the soldiers perform can take weeks, rather than days, without any ability to recharge; therefore he carries many spare batteries. Such technology demands significant power, with infantry platoons carrying about 700 pounds of batteries (17 pounds per soldier) 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. This load not only slows down soldiers but also poses risks of muscular and skeletal injuries due to excessively heavy packs.
As military platforms and systems such as land vehicles are fitted with more electronic equipment, their electrical energy demands will continue to increase and it is anticipated that their limited electrical energy storage capabilities (i.e. their batteries) will present issues during the vehicles’ life of type. Furthermore, the development of hybrid electric vehicles (HEV) and electric vehicles (EV) has introduced new performance requirements on the batteries used in land vehicles.
The military’s evolving needs require batteries that are not only lightweight and long-lasting but also resilient under extreme conditions.
Because the rate at which chemicals within a battery react is dependent on temperature, reactions proceed more quickly as temperature increases. This means that, for military batteries, great care has to be taken to ensure that the power generated in a cold-weather environment is sufficient to meet a soldier’s needs.
On the other hand missions in high-temperature regions face overheating challenges. It is well known that certain battery cell chemistries, lithium-ion for example, are susceptible to overcharging and to over-discharging operational problems. Occurrences of these conditions and other events can cause a reduced useful battery life. In the extreme, destructive mishaps involving intense heat, fire, and even explosion can occur. Because a battery is an energy storage device, by definition a good battery contains large amounts of energy in a confined space.
Key challenges include:
- Temperature Sensitivity: Batteries must perform reliably in both cold and hot environments. Reactions within batteries are temperature-dependent, affecting performance in extreme weather conditions.
- Overheating Risks: High temperatures can cause certain battery chemistries, like lithium-ion, to overcharge or over-discharge, leading to reduced lifespan or even catastrophic failures.
- Safety Concerns: The flammability and risk of explosions associated with current lithium-ion batteries necessitate safer alternatives.
The reliance on batteries comes with substantial financial and logistical costs. According to the U.S. Army Research Laboratory, a typical infantry battalion spends over $150,000 annually on batteries, making it the second-highest expense after munitions. The high demand for power, coupled with the limitations of current battery technologies, necessitates innovative solutions.
Emerging Solutions for Military Power
Addressing the power challenges faced by modern soldiers is critical to enhancing their agility and effectiveness on the battlefield. Military organizations are actively pursuing innovative strategies to reduce the logistical burden of power management while increasing operational efficiency. These emerging solutions focus on creating smaller, lighter, and more versatile power sources tailored to the unique demands of military operations.
Smaller, Lighter Power Sources: One of the primary goals is to develop compact and efficient batteries that can provide the necessary power without adding significant weight to the soldier’s load. Advances in battery chemistry, such as solid-state batteries and lithium-sulfur batteries, are promising in this regard, offering higher energy densities and longer lifespans in smaller, lighter packages.
Renewable Energy Options: To further reduce dependence on traditional power supplies, the military is incorporating renewable energy solutions, such as flexible solar panels, into the soldier’s gear. These lightweight, portable panels can be easily deployed in the field, providing a continuous source of energy for charging batteries and powering devices, even in remote locations.
Wearable Energy Solutions: Wearable technology is another area of focus, with the integration of conformal wearable batteries (CWBs) that can be seamlessly incorporated into uniforms and gear. These batteries are designed to be flexible and lightweight, allowing soldiers to carry power sources without sacrificing mobility or comfort.
Integrated Soldier Power and Data Systems (ISPDS): ISPDS technology combines power and data management into a single system. It enables efficient connectivity and control over multiple wearable devices, using intelligent power management to prioritize energy supply and extend battery life.
Integrated Soldier Power and Data Systems (ISPDS) are advanced technologies designed to enhance the operational efficiency of dismounted soldiers by providing centralized power management and data connectivity. ISPDS enables soldiers to manage multiple wearable devices simultaneously, ensuring seamless data transmission and power management. This technology significantly improves situational awareness on the battlefield, allowing soldiers to make informed decisions quickly and enhancing mission effectiveness.
ISPDS functions as a versatile hub, connecting various devices through a personal area network (PAN) using USB, Ethernet, and other ports. These hubs not only facilitate data exchange but also power or recharge devices via a centralized lithium-ion battery. This approach reduces the need for each device to have its own battery, thereby lightening the load soldiers must carry.
The system employs intelligent power management to prioritize energy supply based on mission-critical needs, optimizing battery life and device usage. Soldiers can monitor and manage power through integrated mission software, enabling them to conserve energy and focus on essential tasks.
ISPDS addresses the challenge of “battery fatigue” by integrating data and power management into a single lightweight device, reducing the burden on soldiers and ensuring that wearable technologies enhance rather than hinder their effectiveness on the battlefield.
Nuclear Batteries: In pursuit of long-lasting and reliable power, the military is also exploring the potential of nuclear batteries. These power sources, based on radioactive decay, can provide energy for years without the need for recharging or replacement, making them ideal for long-term missions and remote operations.
Thermal Management Systems: Efficient cooling methods, such as active air and liquid cooling, are crucial for maintaining battery performance and safety. Air cooling, while simple, is less efficient than liquid cooling, which offers better thermal management but adds complexity.
Advanced Battery and Power Management:
To ensure that all these power sources are used as efficiently as possible, advanced Battery Management Systems (BMS) are being developed. These systems not only optimize the use of available power but also enhance safety by monitoring and managing the health and performance of batteries in real-time.
These emerging solutions are set to revolutionize how soldiers manage power in the field, reducing the need for frequent resupply missions and enabling greater operational autonomy. By integrating these technologies, military forces can ensure that their personnel remain agile, well-equipped, and ready to face the challenges of modern warfare.
Current lithium-ion batteries (LIBs) pose significant safety risks due to their reliance on flammable and combustible materials, making them prone to catastrophic fire and explosion incidents—often without any prior warning. This vulnerability was starkly highlighted when Samsung Galaxy Note 7 phones were banned from airlines and the U.S. Navy prohibited the use of e-cigarettes on ships and submarines. These measures underscore the urgent need to reduce the flammability of power sources widely used in portable electronics, electric vehicles, and other applications.
To enhance energy distribution and accessibility for troops, the Army and industry are developing Conformal Wearable Batteries (CWBs) and wearable power generation devices that can be integrated into a soldier’s vest or body armor. Future CWBs are expected to offer higher energy densities, which, while beneficial for operational efficiency, also raise safety concerns. When soldiers equipped with these high-capacity batteries engage in combat, the proximity of these power sources to their bodies becomes a critical safety issue. A battery puncture or crush injury could lead to a rapid release of energy, generating intense heat that could ignite or even explode the battery pack. To prevent such incidents, engineers are focusing on creating anti-thermal propagation systems that incorporate chemical, mechanical, and electrical safeguards. These include placing thermal blocks between cells to prevent heat transfer or integrating anti-flame suppression mechanisms that release substances to inhibit ignition. Ensuring that Soldier Portable Batteries (SPBs) fail gracefully under extreme conditions—without causing harm to soldiers or damaging other equipment—requires rigorous testing for explosive decompression, submersion, thermal and mechanical shocks, and other environmental hazards encountered in the field.
Key Functions of a BMS
Battery Management Systems (BMS) are essential for the safe and efficient operation of battery-powered systems because they provide critical oversight and control over the various functions of a battery. A BMS monitors key parameters like voltage, current, temperature, and the State of Charge (SOC) to ensure that each cell within a battery pack operates within safe limits. Additionally, BMS systems balance the charge across cells, prevent dangerous conditions such as thermal runaway, and communicate with other components to optimize energy usage. This comprehensive management not only protects the battery but also enhances the overall reliability and longevity of the energy storage system, making BMS indispensable in applications ranging from electric vehicles to large-scale energy storage solutions.
A Battery Management System (BMS) monitors various critical parameters to ensure the safe and efficient operation of a battery. Key parameters include voltage, where the BMS tracks the total voltage of the battery, the voltage of individual cells, or specific points along the battery pack. Temperature monitoring is equally crucial, as the BMS measures average temperature, coolant intake and output temperatures, and individual cell temperatures to prevent overheating or undercooling. For systems utilizing cooling mechanisms, the BMS also monitors coolant flow, whether air or fluid-based, to maintain optimal thermal conditions. Additionally, the BMS tracks the current entering or leaving the battery, ensuring that it stays within safe operating limits.
A BMS serves several vital roles in managing battery systems:
- State of Charge (SOC) Estimation: Accurate SOC estimation is crucial for understanding the remaining energy in a battery. Advanced algorithms and real-time data processing allow BMSs to provide precise readings, which help optimize battery usage and prevent unexpected power loss.
- State of Health (SOH) Monitoring: SOH monitoring evaluates the overall condition of the battery, including its capacity and degradation over time. This function helps in predicting battery life and scheduling maintenance or replacements.
- Cell Balancing: Effective cell balancing ensures that all cells within a battery pack are charged and discharged evenly. This process prevents certain cells from becoming overcharged or deeply discharged, which can lead to premature failure and reduced battery lifespan.
- Temperature Monitoring: Battery temperature significantly impacts performance and safety. BMSs continuously monitor temperature to prevent overheating or overcooling, both of which can affect the efficiency and safety of the battery system.
- Safety Protection: BMSs implement various safety features to prevent critical issues such as overcharging, overdischarging, short circuits, and thermal runaway. These protections are essential to maintaining the integrity and safety of the battery.
- Communication: BMSs communicate with other system components, including the battery pack, inverter, and control systems. This integration is crucial for coordinated operation and performance optimization across the entire system.
Beyond monitoring, the BMS actively manages the battery’s charging process, particularly in systems with regenerative capabilities like electric vehicles. It controls the recharging process by redirecting recovered energy—such as that generated during regenerative braking—back into the battery pack, which typically consists of multiple modules, each containing several cells. This precise management helps maximize the battery’s efficiency, longevity, and safety
Without a BMS, batteries are at risk of overcharging, overheating, or over-discharging, which can lead to safety hazards, reduced performance, and shortened lifespan. 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.
The Role of BMS in Military Systems
A Battery Management System (BMS) is essential for managing the health, efficiency, and safety of batteries in military devices. It monitors various parameters such as voltage, temperature, current, and state of charge (SOC) to ensure optimal performance. In military applications, where the stakes are high, a BMS must also account for harsh environmental conditions, potential system failures, and cybersecurity threats.
Military operations rely on a wide range of battery-powered devices, each requiring a specialized BMS to ensure reliable and secure operation:
- Wearable Technology: Soldiers equipped with wearable electronics for communication, navigation, and health monitoring depend on BMSs to manage the power supply, ensuring that all devices function without interruption during critical missions.
- Unmanned Systems: Drones, robots, and other unmanned systems used in reconnaissance, bomb disposal, and supply delivery rely heavily on BMSs for energy management. The BMS ensures that these systems have a stable power supply, even in the most challenging conditions.
- Portable Power Solutions: Field-deployed units often carry portable power sources to charge various devices. BMSs in these systems manage charging and discharging cycles, optimize battery life, and ensure safety in rugged environments.
- Vehicle Power Management: Military vehicles, including armored personnel carriers and tanks, use BMSs to manage the complex battery systems that power communication, navigation, and weapon systems. These BMSs must handle the high demands of vehicle operation while ensuring safety and reliability.
Thermal management
Battery thermal management systems are critical for maintaining the optimal temperature of battery packs, and they can be designed as either passive or active systems. The cooling medium used in these systems can be air, liquid, or a phase change material. Air cooling, while simple and cost-effective, comes with certain limitations. Passive air cooling relies on natural convection, while active air cooling uses fans to enhance airflow. Vehicles like the Honda Insight and Toyota Prius employ active air cooling for their battery systems. However, air cooling is often inefficient, requiring substantial power to operate and adding extra weight due to the additional cooling components. This inefficiency can reduce the overall energy efficiency, particularly in transportation applications where weight and power consumption are critical factors.
Liquid cooling offers a more effective thermal management solution compared to air cooling, primarily because liquids have higher thermal conductivities than air. In liquid cooling systems, batteries can be either directly immersed in the coolant or cooled indirectly by having the coolant circulate through the system without direct contact. Direct liquid cooling is more efficient but can be complex and risky, while indirect cooling can result in uneven temperature distribution across the battery pack due to the longer coolant pathways. To mitigate these thermal gradients, increasing the coolant flow rate can help, but this introduces a tradeoff between maintaining consistent thermal conditions and the energy consumption required to pump the coolant faster.
Fault-Tolerance in BMS for Military Use
Fault-tolerance is a critical requirement for military-grade BMSs. In the battlefield, the failure of a battery system can have catastrophic consequences, potentially compromising missions and putting lives at risk. A fault-tolerant BMS is designed to continue functioning even when certain components fail.
This is achieved through redundancy, where multiple sensors, processors, and communication channels are used to monitor and control the battery system. If one component fails, the BMS seamlessly switches to a backup, ensuring uninterrupted operation. For example, in an Unmanned Aerial Vehicle (UAV) used for reconnaissance, the BMS must maintain power to the UAV’s systems even if some sensors or connections fail. This redundancy is vital in preventing total system failure and ensuring that the mission can continue as planned.
A fault-tolerant BMS typically consists of two independent sets of electronic circuits, each responsible for redundantly monitoring and managing the same set of interconnected battery cells. This dual-circuit architecture allows for seamless data collection and command execution, even if one set of circuits encounters a fault.
The BMS is engineered with distinct fault domains, isolating critical functions such as control, monitoring, and cell balancing from the circuits responsible for built-in real-time testing. These fault domains ensure that any issue in one area does not compromise the system’s overall functionality. Built-in tests are conducted within these isolated domains, providing unique test stimuli for each cell measurement to verify the system’s integrity. Cell balancing, a key function of the BMS, is also designed to be fault-tolerant, requiring at least two independent faults in separate fault domains to disrupt balancing or impede the operation of redundant circuits. This robust design ensures that the BMS can maintain optimal performance and safety, even in the most demanding military environments.
Wireless battery management system (BMS)
Recently, Texas Instruments unveiled a groundbreaking wireless battery management system (BMS) for electric vehicles (EVs), offering a significant departure from traditional wired systems. Unlike conventional BMS architectures, which rely on physical control lines and sensing on power cables, this innovative system utilizes a wireless connection between the vehicle and its charging station to transmit vital information. The specially designed communication protocol allows for rapid data transmission, enabling the system to provide real-time information on more than 100 battery cells within milliseconds. Texas Instruments highlights that the power consumption of the wireless chips is remarkably low, with the main node consuming just 294 µW and individual devices consuming 200 µW, making the system both energy-efficient and effective.
One of the primary advantages of this wireless BMS is the reduction in the number of cables required, which enhances both reliability and vehicle efficiency. Fewer cables mean fewer points of potential failure due to physical strain or breakage, thereby improving overall system reliability. Additionally, reducing the number of wires in an EV decreases its weight, which is a crucial factor in extending the vehicle’s range. Every kilogram saved translates to less energy needed to move the vehicle, directly contributing to improved efficiency. The wireless system also simplifies vehicle construction by eliminating the complexity associated with traditional series-wired cell monitors and communication cables. Texas Instruments notes that this system facilitates the implementation of time-synchronized data, likely due to its ability to read all cell voltages within a few milliseconds, further streamlining the battery management process.
However, the adoption of wireless BMS technology also introduces new challenges, particularly in terms of safety and cybersecurity. Unlike wired systems, wireless BMS lacks a direct physical connection between the transmitter and receiver, making it more susceptible to data loss due to noise or external interference. If the wireless connection between the BMS and individual cells fails, the system’s ability to monitor critical parameters like voltage, temperature, and current draw could be compromised, posing significant safety risks.
Furthermore, wireless systems are inherently more vulnerable to cyberattacks. An attacker who gains access to the wireless network could potentially inject false data or take control of the system, leading to dangerous scenarios, such as the car shutting down unexpectedly for safety reasons. Despite these concerns, Texas Instruments has taken significant steps to ensure the safety of their system, as confirmed by TÜV Süd, an independent safety testing service in Germany. Nonetheless, the balance between the convenience of wireless technology and the need for robust cybersecurity will be a critical factor in the widespread adoption of wireless BMS in the automotive industry.
Cybersecurity in Military BMS
The integration of the Internet of Things (IoT) and cloud computing technologies is set to revolutionize battery management systems (BMSs), offering enhanced scalability, cost efficiency, and real-time visibility for lithium-ion battery energy storage systems. By leveraging IoT wireless networks, advanced computing power, and cloud support, these next-generation BMSs can deliver unprecedented levels of performance and monitoring. However, this shift towards interconnected systems also introduces significant cybersecurity risks, as IoT devices are continuously connected to networks, making them prime targets for cyberattacks. A compromised BMS could lead to unauthorized control of battery systems, potentially disabling critical equipment or causing dangerous malfunctions. Therefore, cybersecurity is a paramount concern in the design of military BMSs.
Electric Vehicles (EVs), like all modern vehicles, rely heavily on electronic devices and networked systems for operation, making them increasingly vulnerable to cyber threats. This vulnerability is particularly concerning when it comes to EV battery packs, where the consequences of a cyberattack can be severe. A compromised BMS, for example, could lead to malicious control over the voltage regulator, resulting in either overdischarge or overcharge of the battery pack. Overdischarge can cause rapid internal shorts, potentially damaging the battery within minutes by exploiting energy-intensive subsystems like auxiliary components. On the other hand, overcharging the battery pack can drastically reduce its lifespan, potentially shortening it to less than a year. Even more alarming, such attacks could trigger thermal events, leading to fires or explosions, thereby posing significant physical safety risks to both the vehicle and its occupants.
To mitigate these risks, it is essential to implement robust cybersecurity measures in BMS design and operation. This includes the use of encryption, secure communication protocols, real-time monitoring for anomalous behavior, and regular software updates to patch vulnerabilities. Additionally, developing a layered security approach that integrates both hardware and software defenses can help protect against potential cyber threats.
These systems are designed to protect against hacking attempts, data breaches, and other forms of cyberattacks that could compromise the integrity of military operations. For instance, a BMS in a soldier’s wearable tech gear may be equipped with encryption to protect data transmission between the battery and the control system. If an unauthorized attempt to access the system is detected, the BMS can initiate a lockdown, preventing further intrusion and alerting operators to the potential threat. As EV adoption continues to grow, ensuring the cybersecurity of BMS will be critical in safeguarding both the functionality and safety of these vehicles in an increasingly connected world.
CSIRO Defense-Grade, Cybersecure BMS software
The partnership between an Australian lithium-ion battery manufacturer and CSIRO to develop a defense-grade, cybersecure Battery Management System (BMS) represents a critical advancement in the security and reliability of battery-powered military equipment. This collaboration aims to ensure that batteries, which are integral to various military technologies, remain secure, reliable, and safe, even in the most challenging environments. This advanced software will incorporate a robust cybersecurity layer, featuring end-to-end encryption to protect data exchanges between the battery, its clients, and monitoring services.
A key focus of the project is to determine which cybersecurity threats are worth guarding against, ensuring that the BMS remains both affordable and secure. The system will communicate through an inverter, enabling secure real-time data transmission, analytics, and remote management. This will reduce the risk of battery failure and lower operating costs for users of grid-scale energy storage, ultimately supporting the transition to a more stable and secure renewable energy grid.
A defense-grade, cybersecure BMS offers several key benefits. Enhanced security is paramount, as the BMS will incorporate advanced encryption and cybersecurity measures to prevent unauthorized access and cyberattacks that could disrupt military operations. Improved reliability is another critical advantage; the robust design of the BMS ensures the consistent and efficient operation of battery-powered equipment, even under extreme conditions. Additionally, the cybersecure BMS significantly increases safety by minimizing the risk of battery failures, which could otherwise lead to catastrophic safety hazards, such as thermal events.
This partnership has the potential to impact various applications within the military. For instance, the development of more secure and reliable batteries for electric vehicles (EVs) used by the military could enhance the operational capabilities of these vehicles. The same technology could be applied to Unmanned Aerial Vehicles (UAVs) and other unmanned systems, ensuring their continued functionality in hostile environments. Moreover, portable electronic devices such as radios, GPS systems, and night vision equipment could benefit from the improved security and reliability offered by this advanced BMS technology.
Challenges and Future Directions
Developing fault-tolerant and cyber-secure BMSs for military applications is not without challenges. The complexity of modern battery systems, coupled with the need for advanced features like real-time monitoring and adaptive control, requires continuous innovation. Additionally, the ever-evolving landscape of cyber threats means that BMS cybersecurity measures must be regularly updated and tested to stay ahead of potential adversaries.
Looking forward, the integration of artificial intelligence and machine learning into BMS technology holds promise for further enhancing fault tolerance and cybersecurity. AI-driven BMSs could predict and mitigate potential failures before they occur and adapt to new threats in real-time, providing an even higher level of reliability and security for military operations.
Conclusion
In the context of modern military operations, where power management can make the difference between success and failure, the importance of fault-tolerant and cyber-secure Battery Management Systems cannot be overstated. These advanced systems ensure that soldiers and their equipment remain powered, safe, and connected, even in the most challenging environments. As technology continues to evolve, so too will the capabilities of BMSs, paving the way for more resilient and secure military operations in the future.
References and Resources also include:
https://www.aerodefensetech.com/component/content/article/adt/features/articles/38538
