How often do you think about how much power the device you use gives you? Electricity is an innovation that we take for granted, but it has an interesting and controversial past, and for the first time in history it will undergo major changes. Everything we do depends on electricity, and our dependence on it is only getting stronger. Ensuring sufficient power supply to a wide range of smart devices for Industry 5.0 and the evolutionary transition to Society 5.0 (S5.0) will require smarter energy consumption and energy harvesting through the use of energy management and new energy harvesting and distribution methods. 

Industrial Smart Wearable (ISW) is essential to Industry 5.0 since the human worker will play an ever-more essential role in value creation under this paradigm. The proliferation of more intelligent and advanced industrial wearables would allow workers to perform their tasks safer, faster, and more productively. There is a diverse and growing range of emerging ISW available to businesses, which offer various functionalities in line with Industry 5.0 objectives. Bio-inspired protective gears and exoskeletons can improve industrial workers’ capabilities, strength, productivity, and stability. Head-worn ISWs can enhance human operators’ navigation and information-sharing capabilities, whereas clothing ISWs can use conductive or optical sensors to monitor and track the vitals of the workforce. Experts even pursue embedded tracking ISW that monitors workers’ mental and physical strain and stress. Within the Industry 5.0 context, ISW operates under C-CCP and relies on CAI and Industrial Internet of Things (IIoT) to communicate and interact with other facilitating and emerging technologies such as 3D printers, adaptive-collaborative bots, and autonomous vehicles. Various types of batteries, accumulators and fuel cells are suitable for Industrial Smart Wearable (ISW).

Design Explosion-Proof Ex Batteries for Wearable Devices in Hazardous Environments

Designing explosion-proof (intrinsically safe) batteries specifically designed for wearable devices operating in hazardous environments. electronic devices, requires the use of special technologies. Unique technical and ergonomic challenges that arise when developing such power supplies for compact, wearable electronic devices. The future of explosion-proof wearables depends on advances in batteries, thermal management solutions, and wireless technology with Internet ecosystems, while balancing safety, performance, and user comfort.

Battery Chemistries for Ex Wearables

The selection of battery chemistry for explosion-proof wearables is a critical design decision, balancing energy density, power delivery, safety, and form factor. The most common chemistries considered are Lithium-ion (Li-ion), Lithium-Polymer (Li-poly), Lithium Iron Phosphate (LFP or LiFePO4) and Lithium Thionyl Chloride (Li-SOCl2).

Lithium-Ion (Li-ion) batteries

Lithium-ion batteries are widely used due to their high energy density (100–265 Wh/kg and 250–693 Wh/L) and long cycle life, making them a popular choice for portable electronics like smartphones, laptops, and electric vehicles. They are rechargeable and rely on the movement of lithium ions between electrodes during charge and discharge cycles.   

Despite their advantages, Li-ion batteries pose safety risks, including potential fires or explosions if damaged, misused, or improperly handled. They contain active chemicals that can exhibit thermal instability, leading to overheating and, in some cases, thermal runaway. To mitigate these risks, Li-ion batteries typically incorporate built-in protection circuits that monitor temperature, voltage, and current, preventing overcharging, over-discharging, and excessive temperature rise. They are often sealed in rigid and bulky packages for protection, which can conflict with the miniaturization and flexibility requirements of wearables.

Lithium-Polymer (Li-poly) batteries

Lithium-polymer batteries, often referred to as Li-poly or LiPo, utilize a gel-like or solid polymer electrolyte instead of a liquid one, which eliminates the need for a porous separator and allows for greater flexibility in form factor. This characteristic makes them ideal for integration into curved or irregularly shaped devices, such as smartwatches and wearable health trackers. 

Li-poly batteries have similar electrode compositions to Li-ion but offer enhanced safety due to their more stable electrolyte, which reduces the risk of leakage or combustion. Their flexible packaging materials also contribute to better mechanical stability, reducing the likelihood of physical damage or puncture. While generally having a lower energy density compared to Li-ion, Li-poly batteries can handle higher charging currents and exhibit lower self-discharge rates, improving overall efficiency. However, their manufacturing costs are generally higher due to the more complex production process.

Lithium Iron Phosphate (LFP or LiFePO4) batteries

Lithium Iron Phosphate (LFP or LiFePO4) batteries is a new type of lithium battery with a unique chemical composition. Unlike traditional lithium-ion batteries, this type does not contain nickel and cobalt. A lithium iron phosphate (LFP) battery, also known as a lithium iron phosphate battery, is a type of lithium-ion battery that uses iron phosphate as the cathode material. One important advantage over other lithium-ion chemistries is thermal and chemical stability, which improves battery safety. The stable chemical structure of LFP batteries reduces the risk of thermal runaway. This means they are less susceptible to sudden temperature changes that can lead to fires or explosions. LFP batteries remain stable under a variety of conditions. They do not react as easily to heat or physical stress as some other types of batteries. This stability means that LFP batteries are less likely to leak or swell. LFP batteries can operate from approximately -4°F to 140°F (-20°C to 60°C). Even in extreme temperatures, LFP batteries retain their efficiency better than many other types.

LFP batteries typically have a lower energy density compared to some other lithium-ion chemistries, meaning they store less energy per unit of weight or volume. They have a lower nominal voltage (typically 3.2V or 3.3V) compared to other lithium-ion batteries, which might require adjustments in charging systems. They require specific charging protocols to optimize their performance and lifespan. While stable at high temperatures, they can have reduced performance in extremely cold temperatures. 

Lithium Thionyl Chloride (Li-SOCl2) batteries

Lithium Thionyl Chloride (Li-SOCl2) batteries are primary (non-rechargeable) cells known for their exceptional energy density (up to 500 Wh/kg, with some reaching 730 Wh/kg) and remarkably long shelf life, often exceeding 10 years with a self-discharge rate as low as 1% per year. They maintain a stable nominal voltage of 3.6V throughout approximately 90% of their discharge cycle, making them suitable for long-term, low-power applications where consistent power is crucial and recharging is not feasible.

These batteries can operate in extreme temperatures, typically ranging from -60°C to 85°C, with some capable of -80°C to 125°C, making them suitable for harsh industrial and military environments. While the thionyl chloride electrolyte is corrosive and toxic, proper handling and disposal mitigate safety concerns. Their high internal resistance can sometimes lead to a delay in producing high voltage, but this can be addressed by incorporating a capacitor in the battery pack design to provide peak current.

Comparative Suitability for Wearables in Hazardous Environments

The choice among these battery chemistries for explosion-proof wearables involves a careful balance of performance, safety, and integration requirements.

• Rechargeability vs. Lifespan: Li-ion and Li-poly offer rechargeability, which is vital for frequently used wearables requiring continuous operation over shifts. This allows for repeated use and reduces waste. Conversely, Li-SOCl2, being primary cells, are ideal for wearables in remote monitoring or long-term, low-power applications where battery replacement is infrequent or challenging. The long shelf life of Li-SOCl2 batteries (10-20 years) can significantly reduce maintenance costs and logistical complexities in such scenarios.

• Energy Density and Form Factor: Li-ion batteries offer high energy density, which is crucial for maximizing runtime in compact wearable devices where space and weight are limited. However, their rigid construction and the need for robust, bulky protective packaging for intrinsic safety can constrain wearable design. Li-poly batteries, with their flexible form factor and enhanced inherent safety due to the gel electrolyte, are particularly well-suited for integration into ergonomically designed, body-conforming wearables like smartwatches. This flexibility directly addresses the challenge of creating comfortable and unobtrusive wearable devices.

• Safety and Temperature Range: While all lithium batteries require careful design and management for safety, Li-SOCl2 batteries are noted for containing non-flammable electrolytes, which can be advantageous in certain hazardous environments. Their wide operating temperature range also makes them robust for extreme conditions. Li-ion and Li-poly batteries rely heavily on sophisticated Battery Management Systems (BMS) and protection circuits to mitigate thermal runaway risks. The inherent safety features of Li-poly, combined with its flexible design, offer a compelling solution for many wearable applications where mechanical stress and deformation are common, as these factors can increase the possibility of mechanical damage to the battery and subsequent safety hazards. 

The selection process for an Ex-certified wearable battery involves a nuanced evaluation of these trade-offs, prioritizing the specific operational requirements, environmental conditions, and user experience for the intended application.

Design Principles and Protection Methods for Intrinsically Safe Battery Packs

The design of intrinsically safe (IS) battery packs for hazardous environments is a specialized engineering discipline focused on preventing ignition by rigorously controlling electrical and thermal energy. This involves a combination of fundamental principles and specific protection methods. The battery design meets IECEx standards including Intrinsic safety «i», Increased safety «e», Flameproof enclosures «d», Encapsulation «m», Special Protection "s" and Dust ignition protection by enclosure «t». Our experience in hazardous areas allows us to quickly complete projects in accordance with current standards. IECEx batteries are designed to use the IECEx protection concept, making them safe for use in the required zone. Zone 0 typically uses intrinsic safety or encapsulation, but zones 1 and 2 may use less sophisticated concepts.

IECEx battery design requires special technologies to prevent combustion when used in hazardous locations.

Core Principles of Intrinsic Safety Design

The core principle of intrinsic safety is to limit electrical and thermal energy to levels insufficient to ignite surrounding hazardous substances, even under fault conditions.9 This is achieved through:

• Energy Limitation: Devices are designed to restrict electrical energy and thermal output below the ignition thresholds of flammable gases or dusts. This involves careful selection of components, circuit design, and operating parameters to prevent energy storage or release above certain thresholds. Typical IS designs operate at low voltages (under 30V) and limited current (mA range).

• Protection Measures: Integration of components such as current-limiting resistors, Zener barriers, and isolators to prevent excessive energy transmission into hazardous areas. These components are selected to fail in a safe manner, preventing sparks or excessive heat.

• Redundancy and Reliability: Designs often incorporate redundancy and fail-safe mechanisms to minimize the likelihood of failure and ensure continuous, safe operation. For instance, intrinsically safe barriers typically include at least two Zener diodes in parallel to ensure protection if one fails.

The architectural design of the system is paramount; attempting to limit energy after the design is complete can be very costly. Understanding energy constraints and product requirements from the outset is essential for a successful project.

Encapsulation and Potting (Ex m)

Encapsulation and potting involve enclosing electrical components within a solid, electrically insulating, and thermally conductive compound. This method aims to separate potential ignition sources from explosive atmospheres and to dissipate heat effectively.

• Mechanism: The compound, typically epoxy or silicone, completely fills the enclosure or forms a thick layer around the components. This prevents the ingress of flammable gases or dust and contains any potential sparks or heat generated within the battery, ensuring they do not reach the external hazardous atmosphere.

• Materials: Materials like silicones and epoxies are chosen for their flame retardancy (e.g., UL 94V-0 rating), high dielectric strength, thermal stability, and resistance to moisture, vibration, mechanical shock, and chemicals. Silicones are particularly valued for their flexibility, which helps damp vibrations and reduces internal strain, and their inherent fire-retardant properties.

• Contribution to Intrinsic Safety: Encapsulation and potting contribute to intrinsic safety by:

Preventing Ignition: By sealing components, they prevent sparks or hot surfaces from coming into contact with the explosive atmosphere.

Thermal Management: The compounds can aid in dissipating heat generated by the battery cells, maintaining temperatures within safe limits and preventing thermal runaway. This is particularly important for compact wearables where heat can build up quickly.

Mechanical Protection: They provide robust protection against physical shocks, vibrations, and external pressures, which can cause internal damage and short circuits in batteries.

Electrical Insulation: The compounds offer excellent electrical insulation, preventing unintended current paths or short circuits within the battery pack itself.

While effective, encapsulation can make servicing equipment difficult or impossible.

Current Limiting Circuits (Ex i)

Current limiting circuits are fundamental to intrinsic safety, ensuring that the electrical energy available for sparking or heating is below the ignition threshold of the hazardous atmosphere.

• Components: These circuits typically involve resistors, Zener diodes, and fuses.

Resistors: Limit the current to a specific value, known as the short-circuit current (Isc).

Zener Diodes: Limit the voltage to a safe level, referred to as open-circuit voltage (Voc). At least two Zener diodes are typically used in parallel for redundancy.

Fuses: Act as a fail-safe mechanism, blowing to interrupt the circuit if the Zener diode conducts excessively, preventing the diode from burning and allowing excess voltage to reach the hazardous area. A temperature-sensitive three-terminal fuse can open due to prolonged overcurrent or overtemperature, or be forced open by redundant protection.

• Integration in Battery Packs: For battery packs, current limiting is essential to prevent uncontrolled discharge or short circuits that could lead to ignition. A battery protector IC or eFuse can handle overvoltage, undervoltage, discharge overcurrent, and short circuits more effectively than a simple resistor. These circuits are typically placed between the battery electronics ground connection and the negative pack terminal. The design must also account for voltage drops across current-limiting components to ensure the circuit functions properly under normal conditions.

Explosion-Proof Valves

Explosion-proof valves are a critical safety feature primarily found in prismatic (rectangular) lithium-ion battery cells.

• Function: These valves are designed to safeguard the battery against thermal runaway by releasing internal pressure that builds up due to electrolyte vaporization during thermal events or internal short circuits. Without such a valve, the accumulated gas would lead to excessive internal pressure, potentially causing the battery to explode.

• Operation: The valve monitors internal pressure changes and opens rapidly when pressure exceeds a preset threshold, quickly venting trapped gases and lowering internal pressure. This rapid discharge of excess pressure helps protect users from catastrophic outcomes.

• Requirements: Explosion-proof valves must maintain a consistent working pressure throughout their lifecycle and pass airtight cycling tests to ensure durability under stress. Their design and integration, often involving welding to the battery case, require careful consideration.

Battery Management Systems (BMS)

Battery Management Systems (BMS) are integral to the safe and reliable operation of intrinsically safe battery packs, particularly for rechargeable chemistries like Li-ion and Li-poly.

• Monitoring and Control: A BMS continuously monitors critical battery parameters, including voltage, current, and temperature, as well as the state of charge (SOC).

• Safety Functions: The BMS ensures that the battery remains within safe operating limits, preventing hazardous conditions such as:

Overcharging: Excess voltage can lead to thermal runaway and fire. The BMS prevents this by regulating charge current and voltage.

Over-discharging: Deep discharge can damage the battery and reduce its lifespan.

Overcurrent/Short Circuit: The BMS can open switches (e.g., FETs) to protect the pack against fault conditions, preventing excessive current flow that could lead to overheating or fire.

Over-temperature: High temperatures accelerate battery degradation and increase the risk of thermal runaway. The BMS helps maintain the battery within its optimal operating temperature range (e.g., 25–40 °C for Li-ion).

• Communication and Balancing: In multi-cell or expansion battery systems, the BMS facilitates communication between units to ensure synchronized operation and efficient energy transfer. It can balance cell voltages and regulate current flow to optimize charging and discharging, even when there are differences in state of charge.

By integrating a sophisticated BMS, the overall safety and efficiency of the explosion-proof battery system are significantly enhanced, mitigating risks that could arise from electrical or thermal abuse.

Technical and Ergonomic Considerations for Wearable Integration

Integrating explosion-proof batteries into wearable devices presents a unique set of technical and ergonomic challenges. The inherent requirements for intrinsic safety often conflict with the demands for miniaturization, comfort, and prolonged use in compact, body-worn electronics.

Size, Weight, and Form Factor

Wearable technologies fundamentally require batteries that are smaller, lighter, and more adaptable in form factor than conventional power sources. This is paramount for user comfort and device aesthetics. However, achieving intrinsic safety typically necessitates robust and often bulky protective packaging or enclosures to contain potential hazards. This creates a direct tension:

• Rigid vs. Flexible: Traditional Li-ion batteries are often sealed in rigid packages, which are ill-suited for flexible wearable devices or smart apparel. The need for materials that can withstand impact, temperature fluctuations, and environmental factors without compromising safety adds to the size and weight.

• Conformal Designs: To address this, advancements in battery design, such as conformal wearable batteries (CWBs), are emerging. These are thin, lightweight batteries designed to conform to the user's body or protective plates. Such designs, exemplified by military-grade CWBs, aim to meet stringent performance and safety standards (e.g., MIL-PRF 32383) while minimizing bulk.

• Material Innovation: The development of lightweight battery enclosures using advanced composites like carbon fiber reinforced polymers (CFRPs) and high-performance thermoplastics offers superior strength-to-weight ratios and enhanced protection, crucial for optimizing wearable weight and energy consumption. However, the choice of material involves trade-offs between strength, weight, thermal conductivity, and cost.

The challenge lies in engineering a battery solution that meets the stringent safety requirements of hazardous environments without compromising the portability, comfort, and discreet nature expected of wearable technology.

Power Density vs. Energy Density

When selecting batteries for wearables, both energy density and power density are critical, but they represent fundamentally different characteristics.

• Energy Density: Measured in Watt-hours per kilogram (Wh/kg) or Watt-hours per liter (Wh/L), energy density indicates how much energy a battery can store relative to its size or weight. High energy density batteries are ideal for applications where long run time is paramount, such as devices that need to operate for extended periods before recharging. For wearables, where weight and volume are limited, higher energy density translates directly to longer operational periods. Different types of Lithium-ion batteries typically have high energy density, making them a common choice for long-term use.

• Power Density: Measured in Watts per kilogram (W/kg) or Watts per liter (W/L), power density measures how quickly a battery can deliver energy. High power density batteries excel at rapid energy discharge or recharge, making them suitable for applications requiring quick bursts of power or fast charging.

• Trade-offs for Wearables: For intrinsically safe wearables, a balance between these two densities is often sought.6 While high energy density is crucial for extended battery life, certain wearable functionalities (e.g., real-time tracking, push-to-talk communication, emergency alerts) might demand rapid power delivery. The challenge is that batteries with high flexibility or safety features often have lower energy densities, while high-energy-density batteries may lack mechanical flexibility and inherent safety. Designers must make trade-offs based on the specific application's needs, prioritizing energy density for long-range operation or power density for high-performance, rapid-response functionalities.

Operating Temperature and Thermal Management

Temperature is a critical factor influencing battery performance, lifespan, and safety. Lithium-ion batteries, in particular, are highly sensitive to temperature fluctuations.

• Optimal Range and Risks: Lithium-Ion (Li-ion) batteries and Lithium-Polymer (Li-poly) batteries perform best within a narrow temperature range, typically 25–40 °C. Operating outside this range can have adverse effects: low temperatures reduce capacity and accelerate aging, while high temperatures can lead to performance loss and, critically, thermal runaway. Thermal runaway is an uncontrollable exothermic process where internal battery temperature escalates rapidly (potentially to 600–1000 °C), often accompanied by the emission of flammable gases, smoldering, and combustion. This risk is exacerbated in densely packed battery systems, where heat from a failing cell can trigger a chain reaction (thermal runaway propagation) in adjacent cells.

• Challenges in Wearables: For sealed, explosion-proof wearable devices, thermal management is particularly challenging. The compact design and robust enclosures, while crucial for intrinsic safety, can impede heat dissipation, leading to localized overheating. The battery's proximity to the user also necessitates careful control of surface temperatures to ensure comfort and prevent burns.

• Strategies: Effective battery thermal management systems (BTMS) are essential to prevent thermal runaway and suppress its propagation. This can involve:

Material Selection: Using thermally conductive encapsulation materials (e.g., specific silicones and epoxies) to dissipate heat away from critical components.

Internal Design: Optimizing the internal architecture of the battery pack to allow for better heat distribution.

Monitoring Systems: Advanced BMS actively monitor battery temperature in real-time, with automatic shutdown features if unsafe conditions are detected.

Passive Thermal Management: Exploring materials with high latent heat or high thermal conductivity to absorb or exchange heat with the surroundings. However, passive methods might transfer heat even when not desired or reduce breathability.

The goal is to ensure the battery operates within safe temperature limits, even under continuous use and in varying ambient conditions, without requiring bulky heat sinks that would compromise the wearable form factor.

Ergonomics and User Comfort

For wearable devices, user comfort and practicality are paramount for adoption and sustained use. This becomes a significant design constraint for explosion-proof batteries.

• Weight and Bulk: Intrinsically safe designs, with their robust enclosures and internal safety components, inherently add weight and bulk to the battery pack. This can lead to discomfort, restrict movement, and reduce overall user satisfaction, especially during long shifts in industrial environments. For example, a battery for a radio weighs 200g, while a smartwatch battery can be as light as 50g for the entire device. The design must balance the need for safety with the practical considerations of devices worn directly on the body.

• Form Factor and Flexibility: Wearables are increasingly expected to be flexible and conform to the body. Rigid battery packs, even if compact, can cause irritation or discomfort following extended use. The development of flexible battery chemistries and conformal designs, like Li-poly and CWBs, directly addresses this by allowing thinner, lighter batteries that can integrate seamlessly into various shapes.

• Practicality and Adoption: Workers are more likely to use wearables that are comfortable and convenient for their jobs. If the explosion-proof battery design makes the wearable cumbersome or impractical, its adoption and effectiveness in improving safety and productivity will be limited. 

Consumers prefer comfort and ergonomic design for long-term wear in challenging conditions.

The successful integration of explosion-proof batteries into wearables requires a holistic design approach that considers not only technical safety standards but also the human factors of comfort, wearability, and practicality for the end-user.

IECEx Specific Tests

For IECEx certification, batteries must be "intrinsically safe," meaning they must not produce sparks or release electrical or thermal energy, even when abused (e.g., short-circuited).

Key aspects of IECEx testing for batteries include:

• Energy Limitation Verification: Tests confirm that the electrical and thermal energy levels remain below the thresholds required for ignition, even under fault conditions.

• Short Circuit Testing: Batteries are subjected to external short-circuit tests, often under the most onerous conditions (e.g., specific temperatures that yield the highest currents). The cells must not show signs of leaking or venting, and only a very limited skin temperature increase is permitted. There are ongoing discussions within IECEx regarding the specifics of spark tests for single cells, especially those with high short-circuit currents.

• Thermal Performance Evaluation: Testing is conducted across the specified operating temperature range to ensure safety and performance. This includes evaluating thermal control systems to prevent overheating.

• Mechanical Integrity: While not explicitly detailed for batteries in the provided material, general intrinsically safe equipment undergoes tests to ensure robust housing and resistance to physical damage that could compromise safety.

• Material and Component Verification: The latest standards, such as IEC 60079-11 Edition 7, have increased test requirements for batteries, cells, and supercapacitors, and mandate routine verification with stricter requirements for encapsulation and conformal coatings.

UN 38.3 Transport Testing

The UN 38.3 regulation outlines specific tests for lithium-ion cells and batteries to ensure their safe transport, which directly relates to preventing hazardous events, including explosions. These tests are crucial for any battery, including those destined for explosion-proof wearables, as they address fundamental safety under various stressors.

The eight specific tests (T1-T8) and their pass criteria are:

• T1: Altitude Simulation: Simulates low-pressure conditions during air transport. Batteries are stored at low pressure for at least six hours. Pass criteria: No leakage, venting, disassembly, rupture, or fire; open circuit voltage (OCV) remains at least 90% of initial.

• T2: Thermal Test: Assesses seal integrity and internal electrical connections under rapid and extreme temperature changes (-40°C to 72°C for 10 cycles). Pass criteria: No leakage, venting, disassembly, rupture, or fire; OCV remains at least 90% of initial.

• T3: Vibrations: Simulates vibration during transport. Batteries are subjected to sinusoidal vibrations across a frequency range for three hours in each of three perpendicular positions. Pass criteria: No leakage, venting, disassembly, rupture, or fire; OCV remains at least 90% of initial.

• T4: Shocks: Assesses robustness against cumulative shocks. Batteries are subjected to calculated peak accelerations. Pass criteria: No leakage, venting, disassembly, rupture, or fire; OCV remains at least 90% of initial.

• T5: External Short Circuit: Simulates an external short circuit. Batteries are heated to 57°C and then short-circuited for at least one hour after case temperature stabilizes. Pass criteria: External temperature does not exceed 170°C; no disassembly, rupture, or fire during or within six hours after the test.

• T6: Impact/Crush: Simulates mechanical abuse. Cylindrical cells are impacted by a steel bar, while prismatic, pouch, or smaller cylindrical cells are crushed between flat plates. Pass criteria: External temperature does not exceed 170°C; no disassembly or fire during or within six hours after the test.

• T7: Overcharge (Rechargeable Batteries Only): Evaluates ability to withstand overcharge. Batteries are charged at twice the recommended maximum continuous charge current for 24 hours. Pass criteria: No disassembly or fire during or within seven days after the test.

• T8: Forced Discharge (Cells Only): Evaluates ability to withstand forced discharge. Cells are forced discharged at ambient temperature by connecting in series with a 12V DC power supply. Pass criteria: No disassembly or fire during or within seven days after the test.

These UN 38.3 tests, particularly those prohibiting fire, rupture, or disassembly, directly contribute to the explosion-proof requirements by ensuring the battery's integrity under abusive conditions, thereby mitigating the risk of uncontrolled energy release that could lead to an explosion.

Most common type of intrinsically safe wearable device

Smartwatches: Revolutionizing real-time communication, safety monitoring (e.g., man-down detection, SOS buttons, geofencing), and productivity through digital workflows.

Head-mounted Cameras and Smart Glasses: Used for remote collaboration, inspections, and accessing essential information through voice-first, hands-free solutions.

Wearable Gas Detectors: Critical for identifying potential gas leaks and ensuring worker safety.

Bodycams and Communication Headsets: Facilitate seamless communication, especially when workers are wearing PPE or engaged in tasks requiring both hands.

These devices provide frontline workers with hands-free communication, real-time monitoring, and enhanced productivity, all while complying with stringent safety certifications. These wearables significantly reduce response times to worker emergencies (25–30%), decrease lone worker incidents (20%), and improve compliance accuracy (20%).

Emerging Trends

The field of explosion-proof wearable batteries is continuously evolving, driven by advancements in materials science, connectivity, and artificial intelligence.

• Integration with IoT and AI: Future wearables are expected to become integral parts of broader Industrial Internet of Things (IIoT) ecosystems. This integration will enable predictive maintenance, smart alerts, and automated safety protocols, allowing for smarter, faster workflows and seamless communication between field workers and command centers. AI-enabled solutions are already empowering frontline workers to access productivity gains and reduce error rates.

• Augmented Extended reality (XR): The use of XR in hazardous environments is expanding, requiring robust power solutions that can support complex visual and processing demands while maintaining intrinsic safety.

• Balancing Performance, Safety, and User Experience: A significant ongoing challenge is to balance the competing demands of high energy density, mechanical flexibility, and safety. Batteries with high flexibility or safety often have lower energy densities, and vice versa.6 Designers must make strategic trade-offs based on specific application requirements, for example, by appropriately reducing energy density requirements for electronic textiles where flexibility and safety are paramount.

The trajectory of explosion-proof wearable batteries points towards increasingly sophisticated, integrated, and user-friendly solutions that will further enhance safety and efficiency in the world's most challenging industrial environments. The development and deployment of explosion-proof (intrinsically safe) batteries for wearable devices represent a critical advancement in industrial safety and operational efficiency. The future of explosion-proof wearable batteries is intertwined with the broader trends of the Industrial Internet of Things (IIoT) and artificial intelligence. The seamless integration of these power sources into smart ecosystems will enable enhanced real-time monitoring, predictive maintenance, and augmented reality applications in hazardous areas. The challenge remains to find the optimal balance between maximizing energy density, ensuring mechanical flexibility and maintaining the highest level of intrinsic safety, while prioritizing user comfort and practicality. Continued advancements in battery materials, thermal management solutions, and intelligent design will be pivotal in realizing the full potential of intrinsically safe wearables, further enhancing worker safety and operational efficiency in the most demanding environments.

HydITEx will design explosion-proof (intrinsically safe) batteries to suit your requirements, specifically designed for a wide range of wearable devices operating in hazardous environments.