Which Types of Batteries for Your IoT devices?
Sep. 12, 2025
Choosing the Right Battery for Your Smart Device
Selecting the right battery for a smart device is not an easy task, as it depends on multiple parameters. The battery must not only be compact and lightweight to fit into miniaturized designs, but also remain safe over a long lifespan, thanks to good charge retention. Another critical requirement is the ability to operate across a wide temperature range—suitable for both indoor and outdoor use—while providing a stable output voltage throughout the device’s lifetime.
Before diving into the specific parameters to consider, let’s revisit the basics: What types of batteries are available, and what are their characteristics?
Types of Batteries for IoT Devices and Their Specificities
There are two main types of batteries:
· Primary batteries, which are single-use and not rechargeable.
· Secondary batteries, which are rechargeable and can be used multiple times.
Both types generate electricity through electrochemical reactions between two electrodes, a positive (+) and a negative (−), facilitated by an electrolyte solution. By using different materials for the electrodes and varying electrolyte compositions, manufacturers can produce a wide range of batteries with different properties and voltages.
For example:
· Alkaline batteries are commonly available in stores and widely used in consumer products.
· Lithium batteries, zinc-air batteries, silver-oxide batteries, or combinations of these chemistries are also available, each with unique characteristics suited for specific applications.
Wireless Connected Devices and Lithium Batteries
Wireless connected devices require light and compact batteries with very high energy density and high voltage. For this reason, lithium batteries are best suited.
Lithium batteries offer high performance and reliability. They feature high voltage thanks to the use of lithium as the anode and can deliver an amount of energy per volume up to ten times greater than that of zinc-oxide batteries. Their electrolyte contains no water, allowing use at low temperatures, and some products with specific electrolytes can withstand high or even very high temperatures.
Lithium batteries come in various forms and sizes.
SUNJ’s Lithium Batteries Dedicated to the Internet of Things
Built on over a century of research and innovation in energy storage, SUNJ’s range of miniature lithium-based batteries has been specially designed for connected devices and IoT applications.
We offer three main ranges of batteries for IoT devices:
· LS, LSH, and LSP: Cylindrical primary lithium cells and batteries
· LM/M: Cylindrical primary lithium cells
· MP and VL: Medium prismatic MP and small cylindrical VL rechargeable cells
LS, LSH, and LSP Cylindrical Primary Lithium Cells – 3.6 V
SUNJ’s LS, LSH, and LSP cylindrical primary lithium cells are based on Lithium-Thionyl Chloride (Li-SOCl₂) chemistry, which provides the highest nominal voltage among primary battery chemistries at 3.6 V.
These batteries also feature the highest energy density and can maintain it for up to 20 years. They are extremely robust, capable of withstanding very high temperatures and strong vibrations.
Two types of lithium thionyl chloride cells are available: bobbin and spiral constructions.
· The bobbin construction of the LS range is particularly well-suited for applications requiring very low continuous currents or moderate pulsed currents, such as metering devices or parking sensors.
· LS cells can endure wide fluctuations in pressure and temperature (from -60°C to +150°C) as well as harsh mechanical environments, making them ideal for remote locations and extreme conditions, such as trackers.
When combined with pulse support components like capacitors, supercapacitors, EDLCs (Electrochemical Double Layer Capacitors), or hybrid capacitors, LS cells can handle even higher pulses and temperatures, offering “best of both worlds” performance.
To further enhance performance, SUNJ launched the LSP range, which pairs reliable, low self-discharge Li-SOCl₂ technology with a carefully selected Lithium-ion Capacitor (LiC).
The LiC chosen by SUNJ exhibits very low self-discharge and equivalent series resistance (ESR) across most temperatures, along with high capacitance during pulses. This ensures that the LSP range can meet the 10+ year lifetime required by the new generation of connected devices. In short, the LSP range delivers an optimal balance of pulse-sustaining capability, operating temperature range, and long-term performance stability.
The LSH range features a spiral construction, specifically designed for applications requiring very high pulse currents. Certain models within this range can operate at extremely high temperatures, such as those encountered in oil and gas applications.
LM/M Cylindrical Primary Lithium Cells – 3 V
The LM/M cylindrical primary lithium cells are based on lithium-manganese dioxide (Li-MnO₂) chemistry, with a nominal voltage of 3 V.
LM/M cells feature a spiral internal construction, similar to LSH cells, but with a lower voltage of 3.0 V compared to 3.6 V. If the application’s electronic design allows a cut-off voltage below 2.5 V, this range offers an economical option with a good balance between energy and power. The LM/M range has high surface-area spiral electrodes for maximum current pulse capability and an electrolyte optimized for operation from -40°C to +85°C.
Thanks to their strong pulse capability, LM/M cells are suitable for smart metering devices requiring high pulses, as well as parking sensors and smart farming applications.
Medium Prismatic MP and Cylindrical Small VL Rechargeable Cells – 3.6 V to 3.75 V
The medium prismatic MP and small cylindrical VL rechargeable cells are based on SUNJ’s unique lithium-ion technology. These batteries can be repeatedly recharged after discharge, making them ideal for frequently used devices.
MP and VL batteries offer long cycle life even under harsh conditions, capable of charging and discharging across a wide temperature range. They are equipped with multiple safety features, including an electronic protection circuit, built-in circuit breaker for charger faults, shut-down separator, and safety vent. While this makes them more expensive than most other batteries, their high cycle count (up to 2,800 cycles with only 30% capacity loss) and low maintenance reduce the cost per cycle compared to other chemistries.
Optional state-of-charge (SOC) and state-of-health (SOH) indicators are available to monitor battery performance in your application. Lithium-ion technology provides reliable performance in unregulated outdoor or extreme conditions, both hot and cold, making these batteries ideal for demanding industrial and critical environments.
Which Battery for My IoT Application?
As you will have understood by now, there is no simple answer to that question.
Here are the parameters you must consider when listing all the options for your use case:
· Nominal and cut-off voltage of your electronics: Different technologies and chemistries have different output voltages. You should choose one that will keep your device above the cut-off voltage throughout its lifetime.
· Environment’s temperature: Consider where your IoT device will be deployed to ensure an optimal and continuous power supply.
· Consumption profile and maximum pulse current and frequency:
Li-SOCl₂ bobbin technology is more relevant for limited pulse values and long lifetime.
Li-SOCl₂ spiral, Li-SOCl₂ bobbin with pulse support devices, and Li-MnO₂ are particularly suited for high pulse applications.