Batteries for IoT – Challenges and key factors in maximizing battery life

With 9.9 billion active device connections worldwide as of 2020 and an expected global market worth of more than $1.5 billion by 2025, IoT devices are certainly catching the eye of major businesses and industries.

From self-driving cars to smart wearables, home appliances, security systems, and large-scale applications such as smart retail, telemedicine, and smart cities, IoT is changing the world.

It is no wonder, then, that having the right batteries for IoT devices is significant. Battery-powered IoT devices are only as reliable as their power supply. Therefore, the ability to ensure the power economy and the battery life of a device is more crucial than ever.

The need becomes more self-evident when you look at the significant amount of diverse IoT applications available in the consumer, medical or industrial segments, ranging from smartphones, high-speed sensors, implantable medical devices, wearables to tracking devices. The common requirement for almost all these device classes is lower power consumption and longer battery life.

Significant IoT Applications in 2020

Consumer IoT

  • By 2020, the number of IoT devices in homes will rise to 12.86 billion. Consumer electronics will account for 63% of all installed IoT units.
  • Consumer IoT focuses on individuals or families and usually works on short-range communication for domestic use.
  • Some applications include light fixtures, home appliances such as air conditioners, televisions, coffee makers, smart wearables, self-driving cars, navigation, voice assistance for the elderly, and more.

Commercial IoT

  • Applications of IoT in commercial places such as offices, healthcare facilities, transportation, retail stores and supermarkets, and hotels.
  • 40% of IoT devices will be used in the healthcare industry by 2020.
  • Smart pacemakers, health monitoring systems, smart offices, intelligent supply chain and asset management, location services, and vehicle-to-vehicle communication (V2V) are key commercial IoT applications.

Industrial Internet of Things (IIoT)

  • This is the large-scale application of IoT in factories and industries, focusing on more automated manufacturing and plant processes for efficiency and productivity improvements. IoT can also be used to manage assets and utilities.
  • Some key applications of IoT include digital control systems, statistical evaluation, smart agriculture, industrial big data, smart robotics, and intelligent utility monitoring systems.

Infrastructure IoT

  • One of the major applications of IoT is the creation and connectivity of smart cities, through the use of infrastructure sensors and actuators, smart management systems, and user-friendly apps. 23% of current large-scale IoT projects are smart cities.

Military Things (IoMT)

  • IoT technologies for military purposes, such as smart robotics for surveillance and monitoring, automated deployment systems, and smart wearable biometrics for combat.

Battery Life: The IoT Challenge

Battery life is critical for IoT systems and is also one of the biggest hurdles while designing batteries. IoT systems work on one key principle- to sense the information and transmit it. If an IoT system’s sensor runs out of battery, information cannot be detected or transmitted further, and the entire system is practically rendered useless until replaced with another battery.

The failure of a battery in an IoT system can have mildly disruptive to catastrophic effects depending on its applications. Industrial processes can come to an abrupt halt, a farmer’s crop harvest can be interrupted, a heart patient’s pacemaker can malfunction, or self-driving vehicles can lose navigational control.

In consumer IoT applications, most device batteries rely on mains power and daily recharges. This is mildly inconvenient. On the other hand, for commercial and industrial IoT applications, inefficient power consumption is a major challenge that significantly affects battery life.

It is essential to have reliable batteries with high capacities and excellent efficiencies in IoT applications to avoid continuity loss. A lot depends on choosing the right battery for your IoT applications.

Choosing Batteries for IoT: What You Should Consider

The following are some factors that you should consider when choosing a battery for an IoT device:

Battery Chemistry

  • Most IoT devices use batteries whose chemistry is almost always primary (for one-time use) or secondary (rechargeable) Lithium-based. Other traditional battery chemistries are Lead Acid, NiCd, and NiMh.
  • Some of the commonly used Lithium-based battery chemistries are Lithium Manganese Dioxide, Lithium Thionyl Chloride, Lithium Cobalt Oxide, Lithium Iron Phosphate.
  • Each of these batteries has its own advantages and drawbacks, and a comparative study will show which is the best battery chemistry for specific application needs.

Charge Cycles

  • While choosing rechargeable batteries, you should know how many times they can be charged and discharged. This charging cycle corresponds to the overall life of an IoT system.
  • Batteries can have charge cycles ranging from a few hundred to a few thousand cycles.

Cell Voltage and Voltage Stability

  • Choosing the optimum cell voltage for an IoT device can significantly impact the device’s efficiency and operating costs.
  • Voltage stability also goes a long way in making IoT systems cost-effective and also maximizes effective battery usage.

Self-Discharge Current

  • Batteries drain even when not in use. Naturally, for long-term use and maximum battery life, the self-discharge current of batteries must be as low as possible.

How to Maximize IoT Device Battery Life

Like any other battery, the battery life of an IoT device is determined using a simple formula – the battery capacity divided by the average rate of discharge. Minimizing the rate of discharge of the battery or maximizing its capacity will maximize its overall life.

This can be achieved by using different processors, communication methods and technologies, and software algorithms.

  • For IoT applications where data collection isn’t frequent, keeping the processor in an appropriate standby mode when not in active use can save essential battery life.
  • Clock frequencies, when minimized, reduce power consumption.
  • Minimizing the number of wake operations and performing maximum operations before entering standby mode can increase the battery’s shelf life.
  • Disabling peripherals, when not required, can reduce power consumption dramatically and improve battery life as well.
  • The use of wireless communications can be minimized. Waking the communications circuits only when they have sufficient data for an effective transmission can tremendously increase battery life as low-power communication systems can drain a battery quickly.
  • Testing your batteries in real-world conditions for signal integrity and power consumption can validate battery performance, efficiency, and lifetime.

The Future of IoT Batteries and Their Alternatives

Developing better IoT batteries is as pivotal as choosing an optimum one for your IoT device. Many current batteries pose challenges for smooth and long-lasting IoT functions regarding power consumption, shelf life, setup and operational costs, and efficiency.

This problem has been addressed, and the solution may not be very far away. Some alternatives for IoT technologies that are being researched are:

  • Solar energy for sensors above the ground
  • Piezoelectric devices that generate power from vibrations
  • Tidal and thermoelectric energy
  • Mechanical or kinetic energy harvesting and RF energy harvesting
  • Zinc as an alternate battery component

Conclusion

With better research for improved battery life and optimum power consumption, IoT devices can improve long-term customer satisfaction, device trustworthiness, and business growth. Increased reliability, higher performance efficiencies, and lower operational costs will incentivize the use of IoT in place of traditional systems to make lives easier and the use of technology convenient.

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