High drain and extended temperature models for lithium coin cells
Murata has announced the development of two high drain and extended temperature additional ranges for its offering of lithium coin cell batteries. Building on Murata’s standard and heat-resistant ranges of ‘CR’ battery sizes, the high current type, designated suffix ‘R’, has twice the maximum pulsed discharge rating of conventional models at 50mA (three seconds at 2V or higher, at 50 % nominal capacity, 23°C) and three times the discharge time (45mA pulsed for three seconds, 23°C).
These characteristics make the parts suitable for Low-Power Wide-Area (LPWA) communications devices, including LoRa and SIGFOX with their high peak current requirements. Available in CR2032 and CR2450 sizes with 3V nominal rating, the cells have nominal capacities of 200mAh and 500mAh respectively for discharge down to 2V.
New extended temperature types designated suffix ‘X’ are available in package sizes CR2032, CR2450, CR2477 and CR3677 and have an extended operating temperature range of -40 to 85°C compared with standard types rated at -30 to 70°C. The wider temperature range better matches the typical ratings of electronic parts in more challenging environments such as automotive, with a better cost-performance figure compared with types rated to 125°C. Stored charge loss at high temperature is minimal over time and the CR3677X model delivers the highest capacity of any lithium coin cell, enabling smaller and thinner devices.
Although previously lithium cells have been seen as back-up supplies, the new Murata ranges open up applications where the battery is the main power source. Typical uses are in the Internet of things (IoT), automotive and factory automation where LPWA networks are becoming common with sensors requiring local power supplies. The higher temperature range particularly suits outdoor applications such as smart meters, security and automotive, where the cells can replace conventional cylindrical types.
Vivek Mohan, Director of IoT, Semtech Corporation, a member of the LoRa Alliance and a joint developer of LoRaWAN modules with Murata, commented: “Semtech’s LoRa RFIC SX1261 needs an approximately 25mA power supply current at 3V supply voltage and 42mA at 1.8V in order to achieve an output of ARIB-T108-compliant 20mW. The LoRaWAN standard defines the maximum transmit time at 3 seconds. With Murata’s new high current type lithium coin cell battery, up to 50mA and 3 seconds of current can be used, making it a promising solution for LoRaWAN-compatible small sensor nodes."
The new battery range underlines Murata’s commitment to the growth of IoT, leveraging the four decades of technology development of Sony’s battery operations which Murata acquired in September 2017.