October 27, 2020

Wireless Battery Management System for Electric Vehicles

5 min read
General Motors (GM) will use a wireless battery management system (wBMS) in its electric vehicles...

General Motors (GM) will use a wireless battery management system (wBMS) in its electric vehicles (EVs). The system was developed together with Analog Devices and should be the main driver to power other solutions in e-mobility.

Many market analysts identify the wireless battery management system as one of the key enablers for the wider deployment of electric vehicles, helping auto OEMs avoid the need to redesign complex wiring diagrams for each new vehicle and helping to ensure battery scalability. A robust, reliable and secure system that works well and is protected with the latest IT security measures is critical.

The wBMS can be wirelessly upgraded with new software-based functionality through GM’s over the air Vehicle Intelligence Platform. The wireless system is used for data and diagnostic needs with all the required FCC and CCC certifications to ensure compatibility and cybersecurity provisions to protect our customers’ vehicles from outside tampering.

Battery Management System (BMS)
Electric cars continue to evolve and so does the battery management system.  The adoption of batteries in electric vehicles has directed the electronic design towards a new generation of electric charge monitoring devices.  In addition to calculating the accumulation of electric charge as a performance parameter, monitoring ensures long battery life and avoids situations that could damage the cells and the electric vehicle itself.

The BMS manages the entire array of lithium cells (single cells or entire battery packs), determining a safe operating area, i.e. a safety area within which the battery pack guarantees the best technical and energy performance. The BMS is in practice an electronic system for the complete control of all diagnostic and safety functions for the management of high voltage on board the vehicle and the balancing of the electric charge.

ADuC7039 is a complete system solution for battery monitoring in 12 V automotive applications (Source: ADI)

Wireless BMS
The battery management system is a critical factor in e-mobility. The addition of wireless makes it very attractive but requires a lot of care.  ADI’s wBMS implementation eliminates traditional wired connections, saving wiring and volume in the battery pack, as well as improving design flexibility and simplifying production without compromising the battery.

ADI’s wBMS includes all essential hardware and software parts for power, battery management, RF communication and ASIL-D and module-level safety functions on a single chip. The system enables maximum power utilization per cell, for the best range of the vehicle and supports safe and sustainable zero cobalt battery chemistry, such as lithium iron phosphate (LFP).

In an interview with EE Times, Gina Aquilano, Technology Director for Automotive at Analog Devices (ADI) and Tao Wang, PhD, Battery System Electronics at General Motors have highlighted how wireless technology offers flexibility and modularity that simplifies battery pack design. “This allows OEMs to scale the adoption of EVs more easily. Among the many benefits, wireless batteries weigh less and take up less space than harnessed batteries and this can support vehicle range goals. Unlike wired/harnessed batteries, wireless battery performance can be continuously monitored, helping to inform and optimize future pack design and assembly as well as performance while in-use, including failure detection. One challenge – and significant opportunity – with EV batteries is ensuring second life use and our wBMS provides usage data and intelligence throughout the battery lifecycle, helping to maximize second life use,” added Aquilano.

Wang said that the wireless battery management system will be a primary driver of GM’s ability to ultimately power many different types of electric vehicles from a common set of battery components. “We expect it will help drive GM’s Ultium-powered EVs to market faster, as time won’t be needed to develop specific communications systems or redesign complex wiring schemes for each new vehicle. It also ensures the scalability of Ultium batteries across GM’s future lineup, encompassing different brands and vehicle segments, from heavy-duty trucks to performance vehicles.”

Wireless Battery Management System in EV (Source: ADI)

GM’s new Ultium batteries can be stacked vertically or horizontally inside the batteries. This technical choice allows manufacturers to optimize the layout of the battery packs according to the needs of each individual model. These batteries will have a capacity between 50 kWh and 200 kWh. This means that the brand’s future electric cars will have a range of over 640 km.

He added, “Being a full-line vehicle manufacturer, we had to make several provisions to ensure that the wireless battery monitoring system would be robust enough to cover all of the corner cases in the different segments we currently build in. We are confident that we’ve come up with a solution that’s scalable across our entire future EV lineup.”

The system allows batteries to measure their performance, thus increasing early detection of faults and enabling optimized battery pack assembly. Data can be monitored remotely throughout the battery life cycle: from assembly, transport, through installation, maintenance and second life.

The measurement parameters are the same as with a wired system: voltage, temperature and current. Aquilano emphasized the fact that, with a wBMS , you can manage the batteries more precisely and better understand performance with access to these measurements across its lifecycle.

Aquilano stated how the wireless network is based on 2.4GHz technology and optimized for the battery management application in terms of reliability, availability and scalability while also minimizing power dissipation when not in use. She said: “In a wBMS we are removing the wired communication between the BMS controller and the BMS monitors and replacing it with wireless. BMS data and commands are now communicated wirelessly. We have jointly designed and rigorously tested the system to ensure consistent reliability given the coexistence with other wireless activity in and around 2.4GHz. The system also has industry-leading protocols to secure these transmissions.”

The new wireless battery management system is remotely upgradable with OTA release and can be easily used on all GM electric models; because it has no cables, it will adapt to different vehicles without the need to be redesigned. This should speed up the time and get the first GM electrics on the market earlier. The goal is to launch as many as 20 electric vehicles, using all its brands, by 2023.

wBMS can also be designed for all those uses that involve the use of large cells, such as powering houses or other facilities. In terms of “scalability”, wBMS and Ultium will enable GM to implement batteries on a wide range of electric vehicles, from high-performance sports cars to crossovers, SUVs and heavy trucks.

The post Wireless Battery Management System for Electric Vehicles appeared first on EETimes.

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