This wireless BMS concept car, developed by Linear’s design partner LION Smart, combines Linear’s 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.
According to the company this demonstration of a fully wireless BMS car represents a significant breakthrough that offers the potential for improved reliability, lower cost and weight, and reduced wiring complexity for large multi-cell battery stacks for electric and hybrid/electric vehicles.
The company's high voltage battery stack monitors have been developed to deliver accuracy and reliability, enabling battery management systems to maximise both the battery pack’s performance and longevity.
The LTC6811 from Linear is a complete battery measuring device for hybrid/electric vehicles and is able to measure up to 12 series-connected battery cell voltages with better than 0.04% accuracy. However, by combining the LTC6811 with Linear’s SmartMesh wireless mesh networking system the company believes that it has been able to address the persistent reliability issues that are associated with automotive wiring harnesses and connectors.
Field-proven in industrial Internet of Things applications, SmartMesh embedded wireless networks deliver >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.
By using wireless connectivity it will be possible for more flexible placement of battery modules, making it possible to install sensors in locations previously unsuitable for a wiring harness. Wireless sensors integrated into the SmartMesh network, such as current and temperature monitors, offer the potential for synchronizing these measurements with cell voltages.
“One of our goals in this project was to demonstrate the improvement in range and charging time that can be achieved by using the latest technologies in partnership with leading global players,” explained Daniel Quinger, CEO of LION Smart. “Combining Kreisel Electric’s laser welded 18650 modules with direct liquid cooling and Linear’s SmartMesh IP wireless mesh and its LTC6811 battery monitoring IC, along with LION Smart’s Open BMS, has enabled a battery system with charge time of just 15 minutes, an energy capacity of over 55kWh, with a range of over 400km.”