A wireless BMS concept car, developed with Linear’s design partner LION Smart, combines Linear’s highly accurate battery stack monitors with its SmartMesh wireless mesh networking products in a BMW i3, replacing the traditional wired connections between the battery packs and the battery management system. This addresses the persistent reliability issues associated with automotive wiring harnesses and connections in electric and hybrid/electric vehicles, and simplifies the BMS design and manufacture.
“Linear’s innovations in two critical industry leading technologies enables wireless battery management at automotive reliability levels,” said Erik Soule, Vice President, Signal Conditioning Products for Linear Technology, which is part of Analog Devices. “New designs of electric and hybrid/electric vehicles are increasing rapidly and all of the major automotive manufacturers are searching for ways to improve the performance and reliability of their battery management systems as they move into higher volume production. The wireless BMS concept car, realized through the expertise of LION Smart’s BMS design, showcases our product vision.”
The LTC6811 battery stack monitor is a complete battery measuring device for hybrid/electric vehicles that can measure up to 12 series-connected battery cell voltages with better than 0.04% accuracy. Combining the LTC6811 with the SmartMesh wireless mesh networking acquired from Dust Networks addresses the persistent reliability issues associated with automotive wiring harnesses and connectors.
Field-proven in industrial Internet of Things applications, SmartMesh is based on the 6LoWPAN and IEEE 802.15.4e standards and provides over 99.999% reliable connectivity in harsh environments by employing path and frequency diversity. In addition to improving reliability by creating multiple points of redundant connectivity, the wireless mesh network enables additional BMS capability. The SmartMesh wireless network enables flexible placement of battery modules and improves battery state of charge and state of health calculations. Additional data can be gathered from sensors installed in locations previously unsuitable for a wiring harness. SmartMesh also provides time-correlate measurements from each node, allowing for more precise data collection.
A reference design to enable customers to demonstrate wireless BMS capability, including the LTC6811 battery stack monitor and SmartMesh wireless sensor network, will be available in the first half of 2017.