Extend Vehicle Driving Range with Accurate Battery Management System
March 27, 2018
|By: Tamer Kira and Daniel Miller
Automotive Business Management Director, and Principal Member of the Technical Staff,
Automotive Business Unit, Maxim Integrated
Industry experts project that by 2025, 25% of cars sold will have electric engines. To extend the life of the lithium-ion battery packs inside these vehicles, as well as vehicle driving range, proper management of these packs is critical.
Battery packs powering electric, hybrid, and plug-in hybrid vehicles must be able to operate in a rather tough environment, while withstanding potentially long periods of inactivity. The hundreds or even thousands of individual battery cells that comprise each pack must be precisely managed and the voltages between cells carefully monitored and balanced.
Here are some important guidelines to follow to encourage a long lifecycle for lithium-ion batteries:
- Avoid charging any cell to 100% of its state-of-charge (SOC) or discharging it to 0% SOC, as both will degrade capacity
- Maximize battery pack capacity and minimize degradation by accurately controlling the SOC for each cell
- Ensure that the charge level of all of the cells stays within the recommended SOC range via cell balancing
- Keep a close watch on battery temperature
Lithium-ion battery packs in EVs must be precisely managed for lasting performance
Clearly, a close watch on the battery packs is important, and one easy way to do this accurately is to integrate a fast and accurate battery management system (BMS) into your design. In addition to monitoring battery packs, a BMS also provides real-time diagnostics to ensure proper operation.
Choosing a Good BMS Architecture
There are various BMS architecture types to consider:
- Isolated controller area network (CAN), based on a star configuration
- A UART daisy chain
- Daisy chain with a fast SAR ADC
Learn more about the pros and cons of each BMS architecture type in our article in Electronic Specifier, "Battery Management System Yields Safer EVs." The article notes how the MAX17843 12-channel, high-voltage smart sensor data-acquisition interface benefits applications such as 48V vehicle battery modules or systems, battery packs, high-voltage EVs, hybrid EVs, and super-cap backup systems.