Analog Devices Expands its BMS Offering with Continuous Battery Monitoring Technology
Analog Devices’ BMS solution achieves ASIL-D rating to meet the toughest requirements posed by regulatory agencies
The expanded battery management systems (BMS) support the major battery chemistries, including zero-Cobalt LFP (lithium iron phosphate), being utilized in EVs and in the energy storage systems (ESS) employed in the reuse and recycling of battery packs.
Image courtesy of Analog Devices
Analog Device’s (ADI) BMS products are optimized for 6-18 cell modules, with the new ADBMS6817 able to measure 8 battery cells in series and the ADBMS6815 able to handle 12. The units allow for continuous battery monitoring even when the vehicle is shut off. This not only conserves power, allowing for more travel on a single charge, but by keeping the closest possible watch on the battery system, maximum safety is assured.
ADI’s Commitment the Electric Vehicle Battery Technology
Some months ago, we reported on ADIs collaboration with Volvo. And now, according to China’s SAIC Motors, “Collaborating with Analog Devices has allowed us to scale our electric vehicle range to meet increasingly strict regulations and the growing demands of today’s EV owners.” He goes on to state that “These new BMS solutions will enable us to advance our commitment to safety and at the same time continue to make EVs accessible for mass market consumers.”
And, as per Patrick Morgan, Vice President of Automotive at Analog Devices. “Our customers have come to rely on ADI as the performance leader for BMS, especially as they are challenged to scale their EV fleets and stay ahead of new market requirements.” He also asserts that “Our latest BMS products not only enable new features such as continuous battery monitoring, but also support battery recycling and reuse in energy storage systems to support the circular economy.”
The ADBMS6817 and the ADBMS6815
Both battery monitors feature a total maximum lifetime measurement error of 1.5 microvolts. For high voltage battery packs, the units feature a stackable architecture.
They offer a built-in isoSPI interface allowing for 2 Mb of isolated serial communication through a single twisted pair of up to 20 meter length. The interface can be coupled via capacitor or via transformer and is bidirectional for broken wire protection. This communications link resists the heavy EMI characteristic of the tough automotive environment and emits scant EMI itself.
The image below depicts a typical application of multiple ADBMS6817 8-channel battery monitors in a battery management system. Each ADBMS6815 handles 12 battery cells, rather than 8.
Image courtesy of ADBMS6817 Datasheet
As depicted above, multiple devices can be connected in a daisy chain with one host processor connection controlling all devices. This daisy chain can be operated bidirectionally, serving to ensure continued communication in the event of a fault along the communication path.
Other Important Features
- Using either of the battery monitors, it is possible to measure all the cells in a system in 304 μs.
- Passive cell balancing is possible with up to 300 mA per channel via a programmable PWM duty cycle for each cell.
- In sleep state, the supply current is spec’d at 5.5 μA
- The units feature a 16-bit ADC with a programmable noise filter
- There are 7 GPIO or analog inputs
- Configurable as an I2C or SPI master
- Electric and hybrid EVs
- Grid energy storage
- Large portable power banks
- Backup battery systems
- Both of the new devices are available in 48-lead LQFP packages with exposed pads
Regulatory and Safety Concern
- The units are AEC-Q100 qualified