Safer Electric Vehicles Start with a Fast, Accurate Battery Management System
January 09, 2018
January 9, 2018
|By: Tamer Kira
Automotive Business Management Director, Maxim Integrated
Vehicle manufacturers are increasingly rethinking how they are powering their cars. From concerns about fuel dependency to desires for cleaner air to regulatory rules, there are a variety of reasons driving this change. By 2025, according to industry experts, 25% of cars sold will have electric engines.
Electric vehicles, along with their hybrid and plug-in hybrid counterparts, rely on large lithium-ion battery packs filled with hundreds or even thousands of individual battery cells. To ensure safe, efficient, and lasting operation, it’s critical to precisely manage these battery cells. Voltages between cells must be monitored and balanced. Battery temperature also must be monitored. Doing so can help extend the life of the battery (aligning it with the life of the vehicle) as well as the driving range of the vehicle.
A fast, accurate battery management system can meet these demands. When it comes to battery management systems, you have the choice of different architecture types. The isolated controller area network (CAN) architecture, based on a star configuration, is robust. A break in the communications wire would disrupt only one IC, while the rest of the battery pack remains safe. However, the CAN architecture does come with high bill of materials (BOM) costs, requires a microprocessor and CAN for each IC, and has relatively slow communication speeds. Another option, a daisy-chain architecture, is recognized for delivering reliable communication at a faster rate than an isolated CAN architecture. It is also considerably lower in cost.
A fast and accurate battery management system can help extend the driving range of electric vehicles.
Maxim provides battery management systems that are backed by deep system expertise honed over the past decade as well as an extensive IP portfolio. They enable ASIL D safety compliance. They were developed with a proprietary daisy-chain architecture and fast SAR ADC, which produce fast and accurate measurements. They also are able to function well in noisy vehicle environments, delivering high EMC immunity performance.
The MAX17843, a 12-channel, high-voltage smart sensor data acquisition interface, is one of Maxim’s newest battery management ICs. With its differential UART communication, this robust battery management system IC delivers trustworthy communication for both centralized and distributed architectures. Since the MAX17843 enables both capacitive and transformer isolation, you can opt to replace the costlier transformer with a capacitor. By doing so, you can save up to 90% of your isolation BOM costs and also lower the failure-in-time (FIT) rate.
Maxim’s new battery management system technology, including the MAX17843, offers the industry’s only single-chip solution to achieve ASIL D compliance. To be sure, some OEMs only require ASIL C compliance. However, having an ASIL D-compliant IC makes it easier to implement an ASIL C solution. The MAX17843 has a FIT rate below one. ASIL C requires the FIT rate to be under 100 for the system. Given that an electric vehicle might have eight or more such ICs in their system, you can see how an IC with a lower FIT rate would make it easier to keep the rate under 100 for the system. The MAX17843 also meets ISO 26262 requirements, along with TUV certification in design and management process.
Watch the video below for an overview of this IC. You can read the data sheet, request a sample, or purchase an evaluation kit by visiting the MAX17843 webpage.