As EV battery voltage increases, so does the potential for damage. The software in battery management systems becomes key for diagnosing battery health and ensuring the vehicle’s functionality.
Auto electronics supplier Visteon has developed a wireless battery management system with General Motors that will launch on the GMC Hummer electric pickup this year.
The system monitors the health and state of charge of battery packs — critical metrics to observe as the fleet becomes more electrified. The design is also modular so the system can be used in different electric vehicle platforms, said Visteon CEO Sachin Lawande.
Lawande: Critical to manage well
It also reduces the chance of battery failure, maximizes vehicle performance and cuts materials costs.
"A battery management system is a critical element of the battery pack itself," Lawande told Automotive News. "If you do not manage them well, it could cause a fairly significant impact to the health of other electronics and health of the vehicle."
To Lawande, a management system is "the brains of the entire powertrain of the EV."
Visteon wanted to improve on current wired systems, which face reliability issues and require heavy and costly wiring harnesses. Most have a central box with copper wires that go to each of the battery's cells, in some cases as many as 1,000.
With the wireless system, each set of modules within a pack has a wireless transmitter connected to its individual cells. The module communicates wirelessly with the central unit about the state of the cells, ultimately reducing the copper, weight and cost typical of wired systems.
"It makes little sense in today's era to build a wired solution because of all of the limitations," Lawande added.
Another benefit of the wireless system is its flexibility.
"You can come up with a modular battery concept that you can then arrange in different formats without redesigning the battery management system every time," Lawande said. "When you think of building a battery pack, it would be a shame if every time you needed to build a vehicle model, you have to build a battery pack to exactly fit that model. That would be a very expensive proposition."
Visteon has historically been a supplier of vehicle electronics, cluster displays and connected experiences. But over the past few years, the company has considered ways to capitalize on the growing EV space.
"We looked at the trend that was happening with EVs and looked at where we could play, and the battery management system required similar electronics capabilities and software as our cluster business," Lawande said.
The company first partnered with GM on a wired battery management system. The two have since evolved their partnership to include the wireless technology, which also uses components from Analog Devices Inc.
The system — which Visteon says reduces time to market given its scalability and modularity — will be made standard on all GM models powered by Ultium batteries. It's manufactured at Visteon facilities in Reynosa and Chihuahua, Mexico, and Shanghai.
As EV batteries become higher-voltage, the potential for damage becomes greater. That's where the software in battery management systems is key: for coordinating the needs of the motor with the capability of the battery, diagnosing battery health and ensuring an EV's overall stability and functionality.
"How does temperature play a role or factor in the life of the battery or the performance of the battery? When does it make sense to maintain the temperature at a certain level, or within a certain range, for maximizing the life and performance?" Lawande posed. "All of these things, based on experience, become the responsibility of the battery management system."
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