Low-power wide-area networks (LPWAN), such as LoRaWAN and Sigfox, are designed to facilitate long-range communications between sensors and other connected devices at low data rates, while using very little power. There are multiple ways to power LPWAN applications, however the majority will be independent of mains power and will require a battery solution that can last for many years. The first decision in selecting the correct battery will be between a primary (non-rechargeable) or rechargeable technology. In some situations a power source such as solar energy could be used to maintain battery charge, but in most cases the solution will be a primary one.
The choice of primary battery solution will depend on many factors with the most important being:
- Space available
- Application working voltage
- Battery capacity required
- System cut-off voltage
- Background current of the application
- Pulse profile of the application
- Conditions that the device will be used in, especially the temperature conditions
- Life expectancy of the device
- Cost of the battery solution
- Shelf life and self-discharge of the battery technology chosen
There are many primary battery solutions available, each with their own characteristics suiting to different application environments. Find out more about each technology and their technical features below.
|Chemistry / technology||Voltage||Typical energy density||Typical operating temperature range||Typical capacity||Charge retention||Type / Size|
|Alkaline||1.5 V||143 Wh/kg||-18°C - +55°C||1700 - 3000 mAh||Sel-discharge 3% per year at 20°C||AA - D|
|Lithium iron disulfide||1.5 V||297 Wh/kg||-40°C - +60°C||Retains 95% after 20 years at 21°C||AA and AAA|
|Silver oxide||1.6 V||130 Wh/kg||-20°C - +60°C||14 - 180 mAh||Retains 85% after 2 years at 21°C||Button cell|
|Lithium mananese dioxide||3 V||300 Wh/kg||-20°C - +60°C (high temperature variations up to 125°C available)||25 - 1000 mAh||Self-discharge less than 1% per year with a shelf life of 10+ years||Coin cell - 1025 (2.5mm thick x 10mm diameter) to 2477 (7.7mm thick x 24mm diameter)|
|Lithium maganese dioxide cylindrical cell||3 V||300 Wh/kg||-20°C - +60°C (high temperature variations up to 125°C available)||Self-discharge less than 1% per year with a shelf life of 10+ years||Cylindrical cell|
|Lithium Thionyl Chloride||3.6 V||760 Wh/kg||-55°C - +85°C (high temperature variations up to 125°C available)||1200 mAh - 38 Ah||Self-discharge less than 1% per year with shelf life of 10 years||Cylindrical - 1/2 AA to DD|
Alkaline - 1.5 V
Alkaline batteries are commonly used in consumer electronics such as toys, radios ,clocks and remote controls and are easily available from retail outlets. They also have many applications in industrial applications where low cost, easy availability and good pulse capability are important considerations. With a voltage of 1.5V and ranging in size from AAAA to D size they offer good energy density at 143 Wh/kg. Various versions of the technology are suited to low / medium / high drain applications. The recommended temperature range for alkaline batteries is -18 to +55°C. Cylindrical alkaline batteries will lose approximately 3% of their capacity per year when stored at 20°C.
Want to find out more about VARTA alkaline 1.5 V cylindrical cells? Get in touch with our technical specialists to discuss your requirements.
Silver oxide - 1.6 V
Silver oxide primary batteries are widely used in electronic equipment that requires a small compact power source. The high volumetric energy density of the silver oxide button cell (130Wh/kg), and its ability to deliver the energy at relatively high current drains, makes it ideal for miniature devices where space is limited. The silver oxide battery also has an extremely stable discharge voltage, good shelf life, and ability to operate over a wide temperature range. The open circuit voltage of the silver cell is 1.6 V with a typical median operating voltage of 1.2 to 1.5 V. Capacity is typically between 14 mAh and 180 mAh, while charge retention is 85% after two years of storage at 21°C, and temperature range is typically -20° C to +60° C.
Want to find out more about VARTA silver oxide 1.6 V button cells? Get in touch with our technical specialists to discuss your requirements.
Lithium manganese dioxide - 3 V coin cell
Lithium manganese dioxide 3V coin cells range in size from 1025 (2.5mm thick x 10mm diameter) to 2477 (7.7mm thick x 24mm diameter). Capacities range from 25mAh to 1000 mAh and cells have a high energy density of 300 Wh/kg. The bare cell can be installed into a suitable coin cell holder for ease of replacement, or modified with the addition of PCB tags for permanent mounting. Standard CR cells have an operating temperature range of -20° C to +60° C but high temperature variations of these batteries are capable of temperatures up to +125° C. Storage life can be over 10 years with a self discharge of less than 1% per year.
Want to find out more about VARTA lithium manganese dioxide 3 V coin cells? Get in touch with our technical specialists to discuss your requirements.
Lithium manganese dioxide - 3 V cylindrical cell
Lithium manganese dioxide 3 V cylindrical cells are available in two styles – bobbin construction and spiral wound. Each style has particular characteristics with the bobbin style being maximised for long life and the spiral wound for high power. The choice of cell will depend on the power profile required and life expectancy of the battery in the application. A wide variety of diameters, lengths and capacities are available. The bare cell can be installed into suitable spring clips for ease of replacement, or modified by the addition of PCB tags or cable assemblies. Standard CR cells have an operating temperature range of -20° C to +60° C but high temperature variations are capable of temperatures up to +125° C. Storage life can be over 10 years with a self discharge of less than 1% per year and the cells have a high energy density (300Wh/kg).
Want to find out more about VARTA lithium manganese dioxide 3 V cylindrical cells? Get in touch with our technical specialists to discuss your requirements.
Many battery chemistries are available that are suitable for powering LPWAN-enabled IoT sensor nodes. Each has a set of tradeoffs that favour some applications over others. The final choice will depend heavily on the specific requirements of the application. Our pan-European team of technical specialists work closely with VARTA to help you find the right battery solutions for your LPWAN designs. Click here to discuss your battery requirements with a member of the team, or find out more about VARTA here.
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