Your Guide How to Choose Rechargeable Batteries for IOT Devices

IOT is very common in our daily life for GPS trackers, wearable devices, and medical sensors, but people are struggling with the IOT battery’s limited life,  fast power decay, high maintenance, and non-compliant certification. This article gives a complete guide on how to choose the right batteries for IOT devices and helps you to make the right decision.

What is an IOT battery?

An IOT battery is a power supply specially designed for Internet of Things(IOT) devices, which are connected in a special network enabling data collection and communication.

IOT batteries are widely used in sensors, trackers, wearables, and gadgets, delivering stable power for various functions, such as temperature control, positioning, and health monitoring. 

What Are the Key Factors When Choosing IOT Battery?

When choosing the right battery for IOT devices, you need to know the power consumption, lifespan, temperature, to choose the right battery for  IOT devices.

Power consumption

First,you need to identify whether your IOT devices are low-power IOT devices or high-power IOT devices. Generally, there are two methods to identify that.

        Method 1: Follow the video below to get the detailed power consumption value.

        Method 2:Refer to the table below of power consumption benchmarks.

 For low-power IOT devices, mostly coin cell batteries of CR2032, CR2450 are suitable. For high-power IOT devices and a 10-year lifespan, rechargeable large battery packs such as Li-ion battery or lithium polymer battery are suitable.

Lifespan

 -Low-power IOT devices require a short lifespan of 1-2 years to choose LiMnO2 battery.

 -Low-power IOT devices require a long lifespan of 10 years to choose LiSoci2 battery.

-High-power IOT devices normally use rechargeable batteries, such as li-ion battery or lithium polymer battery.

Follow the steps below to measure the primary IOT battery life.

Battery Type & Nominal Voltage

            –Alkaline battery:AA/AAA typical size. 1.5V nominal voltage and non-rechargeable.It’s mainly used for low-cost, 1-year life and low-power consumption IOT devices for consumer applications.

          – Lithium Primary battery (LiMnO2 Battery):CR2032, CR123A typical model 3.0V nominal voltage. It’s mainly used for low-power consumption and short lifespan IOT devices, such as a meter, data sensor,temperture sensor.

         –Lithium Primary battery(LiSoci2 battery): ER14505 and ER14250 typical model. 3.6V nominal voltage. It’s mainly used for low-power consumption and 10-year-long-life IOT devices, such as sensors, smart meters, and asset tracking.

       –Li-ion battery:18650 and 21700 typical models. 3.7V nominal voltage. It’s mainly used for high-power IOT devices, such as industrial IOT, GPS trackers, wearable devices, and solar-powered devices.

       –Li-Polymer battery: Flexible and customised size. 3.7V nominal voltage. It’s mainly used for line-powered or frequently charged devices, such as gateways, smart homes, and video cameras.

       –Lifepo4 battery:18650,26650 and 32700 typical model. 3.2V nominal voltage. It’s mainly used for safe and long cycle life IOT devices, such as solar-powered devices, and industrial     IOT.

      –NiMh battery: AA, AAA typical size. 1.2V nominal voltage. It’s mainly used for rechargeable consumer devices, such as a remote controller.

Capacity, Size &Energy Density

–Capacity: The IOT battery capacity depends on its size, based on a certain chemistry. The IOT battery must contain enough capacity to deliver the current draw meeting the device’s power demand.

–Size: Considering the size limits, the lithium polymer battery is the perfect choice for a customised size for any IOT devices without space limits and output the maximum energy.

–Energy Density: Both Lipo battery and Li-ion battery feature a high energy density of around 250Wh/kg, which can maintain more capacity than other battery types in the same size.

Temperature condition

 –Low Temperature: Some IOT devices are used under extreme -40℃ low temperatures, so only low temperature battery can power the IOT devices normally.

–High Temperature: Some IOT devices are used under 80℃ high temperature applications, so only high temperature battery can power the devices normally.

–Wide temperature: If the IOT devices both need low and high temperature operation, wide temperature battery can support the operation.VTCBATT Lisoci2 battery and 18650 Li-ion battery are wide temperature battery types, supporting -40℃ to 85℃ extreme temperature operation. VTCBATT’s special zero temperature charging solution enables the low temperature battery to charge under 0℃.

Electromagnetic Interference

Some IOT devices of RF radio have very strong EMI interference in signaling, which can disrupt the working of a normal battery PCB. Some battery manufacturers like VTCBATT specially design the PCB circuit protection against electromagnetic.

Even under strong electromagnetic interference, the VTCBATT IOT battery can work normally without a power failure.

Part 4:Why Rechargeable Batteries Are the Smart Choice for IoT?

       Due to low cost and simplicity, non-rechargeable batteries such as alkaline and LiMnO2 batteries are the former dominant in IOT applications. But now rechargeable batteries are the winner in the table below:

Non-rechargeable battery VS rechargeable battery in IOT devices

Rechargeable battery solution will become the main trend in IOT applications, driven by the technological factors of multiple energy densities, safer, longer cycle life,fast-charging capability, and wireless charging.

Part 5:How can battery life in IOT devices be optimized?

Commonly, all people want a long-life battery IoT device to save costs. Below are five effective measures to prolong the battery life in the IOT devices.

–Power Management: Adjust the workload voltage and frequency to avoid overcharging and overdischarging, and set the sleep mode in idle status to save power consumption.

-Efficient communication protocols: Use lightweight protocols of MQTT-SN, CoAP, and set fast connections like BLE, LoRaWan.

-Hardware optimization: Select energy-saving sensors and maximum power switches and converters.

-Software optimization: Use local data processing to minimize transmission frequency and maximize sleep modes.

-Charging Speed and Convenience: Use 0.2C-0.5C charging current to prolong the battery life.

–System&Network Optimization: Adopt edge computing to allow local data processing to reduce power consumption.

Part 6:What’s the safe operation and maintenance for IOT battery?

6.1 Safe Operation Caution

    – Discharge the battery at a maximum 1C current to balance the demand of high power consumption and extended lifespan.

    – Use the specified charger at the correct voltage and CC/CV mode till the end current at 0.01C to avoid overcharging.

  – Integrate the battery with the power management system and communication protocol to control the power consumption effectively.

  – Operate under -20℃ to 60℃  to avoid temperature aging for a normal battery. 

 6.2 Battery Maintenance and Storage Tips

    –  For long-term storage, take the battery from the IOT devices.

    –  Keep the rechargeable battery voltage around 3.7V-3.8V before storage.

    –  Check the voltage periodically for longer storage.

    –  Keep the battery in cool and dry places.

    –   Keep the battery away from heat and fire.

   6.3 Maintenance of IOT batteries

       Remote IOT devices are mostly lithium battery-powered to allow long-distance working of IOT network, which is integrated with a battery management system supporting battery data monitoring and reporting to avoid power failure. TI BQ40Z50 IC is commonly used in rechargeable IOT battery solutions for real-time data monitoring. Fully integrated in 1-Series, 2-Series, 3-Series, and 4-Series rechargeable IOT  Li-Ion or Li-Polymer battery packs, this chip can report the accurate record of available capacity, voltage, current, temperature, and other critical parameters to the IOT system host controller over an SMBUS v1.1 compatible interface.

Part 7: What are the Applications for IOT Battery?

        IOT devices are widely used in different fields to bring great convenience and comfort in our homes and work, empowered by technological strength and revolution.

• Smart Home 

In a smart home, the IOT curtain can open and close the curtain automatically as the brightness of the sunlight. All the electrical appliances are connected via a mobile APP for button switching, and everything is under your control from anywhere.   

• Industrial IOT 

Industrial IOT includes temperature logging, air quality sensors, asset tracking, and beacon detectors, which are integrated with a software system to collect and report data for our industrial usage.

• Wearable Devices

  Wearable devices, such as a smartwatch and health monitor, can collect our body’s health data during sleep and sports, which helps people know their health situation and facilitates doctors’ diagnosis quickly.

• Logistics

Benefited by IOT technology, now people can trace their parcels and packages via the network easily. The IOT technology also boosts the online purchase services and transportation convenience.

Part 8: What are the common challenges and solutions for battery solutions for IoT devices in the future?

In the future, the IOT devices will be scaled up to trillions, deployed in our environment to bring great convenience. As the core part of IOT devices, IOT lithium battery seriously constrains the IOT devices revolution and upgrade.

There are future challenges to be solved with urgency.

– Resource limits: IOT lithium battery manufacturing is restricted by the key materials of lithium and cobalt mining, which fluctuate greatly due to political policy and limited natural resources.

– Waste and Recycling: After 5-10 years, millions of IOT batteries end their lifespan. It

  It will be a huge and tough task to recycle the devices, which are currently in use, without a clear and effective solution.

–Maintenance: It’s not economic and logistical to replace billions of IOT batteries at the end of life. 

–Power Constraints: With the AI telecommunication rise, more and more power-intensive tasks are required for data transmission over long distances, demanding more powerful IOT batteries.IOT devices are deeply integrated into security, with computationally expensive cryptography draining the IOT battery quickly and creating an attack vector.

–Environment: With the deep exploration in space, the deep sea, the Volcano, and the Glacier, new battery solutions for IOT devices demand chemistry and physical revolution in wide temperature performance, pressure-resistant, and radiation-free.

A multi-pronged approach for future IOT applications.

-High-Power New Battery Technology: New battery technology chemistry, like solid-state or lithium-sulfur battery, has high-density and high-power.

–Solar-Harvesting IOT devices: Use a rechargeable battery for IOT devices integrated with solar harvesting to reduce the battery consumption and prolong the lifespan of IOT batteries.

–Battery-Free IOT devices: Super-capacitor or micro-batteries will be the ideal hybrid harvesting for battery-free IOT devices.

 Part 9: What’s the Market Dynamics & Supply Chain of IOT Lithium battery?

Since battery solutions for IOT devices are a complete application-specific ecosystem, the market dynamics depend on IOT’s longevity and power, which means rechargeable batteries will be the main trend in IOT devices.

Giant Asian countries like China, Japan, and Korea are the dominant players in IOT lithium battery manufacturing for rechargeable batteries. Chinese manufacturers for rechargeable battery like VTCBATT, are on the fast track to shape the future by offering customization, high power, long lifespan, wide-temperature operation, and AI management for IOT applications.

Part 10: FAQ

1. What type of rechargeable battery is best for IoT sensors?

A: There are several different factors to choose the best rechargeable battery for IOT sensors.

• Size: For a flexible and compact size, a lithium polymer battery is the best choice for customization in various sizes and shapes to maximize energy output in limited spaces.

• Lightweight: Most IOT sensors are portable and taken to different places. Formed by soft aluminum film, the lithium polymer battery is much lighter than other rechargeable batteries.

• Cost: Cost is a key factor in determining the IOT batteries. Thanks to automated mass production in standard models, Li-ion batteries are much cheaper than rechargeable batteries like lipo batteries and LiFePO4 batteries.

•  Longevity: Featuring 6000+ cycles, the Lifepo4 battery can power the IOT devices for 10+ years.  Even under solar harvesting installation, it can be extended to multiple lifespans.

• High Power: All the rechargeable batteries can support high power discharge capability and large capacity, which depends on the battery models you choose and the size allowed.

• Temperature: All the rechargeable batteries have low-temperature and high-temperature batteries for IOT.But only li-ion and lifepo4 battery currently has wide temperature type.

2.How long do rechargeable batteries typically last in IoT devices?

A: There are two meanings of last: runtime and lifespan.

   –Runtime: The runtime depends on the battery capacity and power consumption.

 It follows the formula below: Runtime=(Battery Capacity/power consumption）*0.9

  –Lifespan: For li-ion battery and lithium polymer battery,the lifespan is 5-6 years based on daily usage calculation.

For lifepo4 battery,the lifespan is 10+ years based on daily usage calculation.

3.Are rechargeable batteries safe for outdoor IoT applications?

A: Yes. Normally, rechargeable batteries are safe for operation. But you need to choose the right battery type first. Some outdoor IOT devices are used in extreme high temperatures or low temperatures,if you use a normal battery, the battery is in risk of fire and explosion. 

4.Can I use regular rechargeable batteries in all types of IoT devices?

  A: No.It’s wrong to use regular rechargeable batteries in all types of IOT devices.

    You need to consider the factors of size, lightweight, cost, longevity, high power, and temperature to choose the right one.

5.What does IoT mean?

A: IOT is a short name for the Internet of Things. Simply, it means connecting different physical objects like electrical appliances at home to the internet and controlling all the appliances on the internet. Take an example, you can switch off the TV, refrigerator, and air-conditioner when you are outside. 

    Examples of IOT Benefits In Daily Life:

   – IOT benefits people’s lives in environmental monitoring, such as a temperature IOT sensor to report the exact temperature.

   -IOT allows logistics to report the position and trace the parcel’s status, boosting the online purchase and goods transportation.

  – IOT devices are widely installed in smart cities to control the solar street lights, monitor the traffic flow, and guard public security. 

6.What are the signs of a failing battery in an IoT device?

A: There are several signs of battery decay in IOT devices.

    –Reduced runtime: Even under a fully charged status, the IOT devices have obviously less runtime than normal operation. 

    – Low working voltage: Even after being fully charged, the battery still shows low voltage or low power indication in IOT devices.

    – Long charge time: The battery takes much longer to charge than normal, and even in high temperatures, which means that the battery has aged.

    – Physical Check for bulge, high internal resistance.

7. What factors affect the performance of IoT batteries?

A: There are many factors to affect the performance of IOT batteries.

• Temperature: A Normal battery can only allow discharge at -20℃ to 60℃ and 0℃-45℃ charging. High temperatures will age the battery and even cause a fire.

                                          It’s extremely dangerous to charge a normal battery under 0℃.

• Current: Some IOT devices require high burst current in sending data, which will drain the battery quickly and shorten the lifespan.

• Use frequency: When an IOT device is in sleep mode with less use frequency, it can reduce the power consumption and prolong the lifespan.

• EMC（Electro Magnetic Compatibility）: Some IOT devices have very strong EMI while signaling, which could interrupt the normal working of the battery PCB and cause the battery to stop charging and discharging normally. 

8. Can I customize the battery specifications for my IOT device?

A: Yes.VTCBATT can help you customize the battery specification specifically designed for your IOT devices. Whether you need a specific IOT lithium battery featuring long lifespan, high power, customized size, or lightweight and wide temperature operation, VTCBATT can fully customize for you exactly as per your demands.

Dr. Emily Li

Principal Scientist

Graduated from Peking University,Dr. Emily Li has 10 years of experience in lithium battery material research and over 10 years of background in new materials application. She is experienced in the lithium battery materials specific application and performance.