Choosing the right battery for your smart device is not an easy task and depends on many parameters.
Not only does the battery need to be light and small-sized to fit into miniaturized designs, but also remain safe all over a long-life expectancy (thanks to good charge retention). Another crucial point for the battery is to be able to operate in a wide range of temperatures (for both indoor and outdoor usages) while offering a stable output voltage throughout the device’s lifetime.
Before going any further into which parameters to look at, let’s get back to basics: What are the various batteries available to us and what are their specificities?
There are two types of batteries: primary batteries that are single-use and secondary batteries that are rechargeable.
Both generate electricity through electrochemical reactions between two poles, positive (+) and negative (-), and thanks to an electrolyte (solution). Using various materials for the poles and different electrolyte compositions, we can make a huge variety of batteries with different properties and voltages. For example, alkaline batteries are widely found in shops and used in consumer products, lithium batteries, zinc-air batteries, silver-oxide batteries or a mix of these chemistries are examples of batteries available on the market.
Indeed, lithium batteries offer high performance and reliability, feature high voltage thanks to the use of lithium as anode, and deliver an amount of energy per volume that can be ten times more than that of zinc-oxide batteries. Its electrolyte contains no water, allowing for use at low temperatures, and some products with specific electrolytes can sustain high and even very high temperatures.
Lithium batteries come in various forms and sizes.
The result of more than one hundred years of research and innovation in the field of energy storage, our range of miniature lithium-based batteries has been specially designed for connected object (IoT) applications.
We offer 3 main ranges of batteries for IoT devices:
Saft’s LS and LSH cylindrical primary lithium cells ranges are based on Lithium-Thionyl chloride (Li-SOCl2) chemistry, which exhibits the highest nominal voltage among primary battery chemistries (3.6 V).
LS and LSH batteries have also the highest energy density and can restore it for up to 20 years. They are very sturdy and can withstand 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 makes these cells particularly well suited for applications requiring very low continuous or moderate pulsed currents such as metering devices or parking sensor applications.
Their ability to withstand broad fluctuations of pressure, temperature (from - 60°C to + 150°C) and harsh mechanical environments make the LS cells ideal for use in remote locations and extreme environments such as trackers. Combined with a pulse support such as a capacitor, super capacitor, EDLC (Electrochemical Double Layer Capacitor) or Hybrid capacitor, they can even sustain higher pulses and combine “best of both worlds” performances. Saft is currently qualifying several external components to allow applications with higher pulses within the LSP range.
The LSH range has a spiral construction. The cells are designed for applications requiring very high pulses. Some specific ranges can operate at the very high temperatures found in oil and gas applications, for example.
The Saft LM/M cylindrical primary lithium cells are based on lithium-manganese dioxide (Li-MnO2) chemistry – 3V.
LM/M cells have a spiral internal construction like LSH cells but exhibit a lower nominal voltage of 3.0 V vs. 3.6 V. If the electronic design of the application is allowing a cut-off voltage below 2.5 V, this range is probably one of the most economic options with a good trade-off between energy and power. LM/M range features high surface-area spiral electrodes for maximum current pulse capability and an electrolyte formulation for optimized operation from - 40°C to + 85°C.
Their good pulse capability makes them suitable for smart metering devices requiring high pulses, but also parking sensors and smart farming applications.
Saft medium prismatic MP and cylindrical small VL rechargeable cells are based on our unique lithium-ion technology. These batteries can be recharged and used again and again after discharge which makes them very convenient for devices that are frequently used. Saft MP and VL batteries boast very long cycle-life in harsh conditions, as they can be charged and discharged over a wide temperature range. Our lithium-ion batteries are equipped with specific safety features – electronic protection circuit, a built-in circuit breaker in case of a charger fault, shut-down separator, and safety vent - which makes them more expensive than most other batteries, but high cycle count (up to 2 800 times with only a 30% capacity loss) and low maintenance reduce the cost per cycle over many other chemistries. In addition, state-of-charge (SOC) and state-of-health (SOH) indicators may be selected as options to monitor your application. Saft’s Li-ion technologies offer unique performances in unregulated outdoor conditions or in extreme conditions, either hot or cold. They are therefore ideal for demanding applications in industrial and critical environments.
Below is a table of our battery ranges and the applications they can be used for:
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:
Still confused about how to move forward with your choice? Why don’t you submit your use case’s consumption profile to our application engineers for a personalized recommendation?
A quick recap of the webinar recently hosted by EMnify where Saft helped shed some light on how to choose the right battery for your Internet of Things connected objects.
What is the impact of the various communication protocols on your application’s power consumption?
Are you planning on shipping your batteries or your IoT devices by air, sea, rail or road? Read to find out everything you need to know before shipping lithium powered IoT devices.