Battery management software (BMS) is a critical application for electric vehicles that monitors an EV’s battery to achieve the highest possible performance, increase the battery’s longevity and provide essential safety functions.
The battery is the largest, heaviest, and most resource-intensive and expensive component of an electric vehicle, and sophisticated BMS is required to optimize that investment. The traditional BMS has three primary functions:
- Monitoring state of charge: The BMS attempts to report how much usable capacity the battery has remaining, which can be a complex function affected by a variety of factors, including ambient temperature and the age of the battery.
- Reducing degradation: Every charge and discharge cycle impacts the health of the battery. However, there are several variables that can be controlled to mitigate battery degradation. Managing charging speed and balancing the charge among individual cells go a long way toward optimizing charging performance and battery health.
- Issuing anomaly alerts: In the event of overheating within a battery cell, the BMS detects the temperature change and makes a split-second decision about whether to shut down the battery and alert the vehicle operator to the issue.
While all battery management software performs many of these same essential functions, that does not mean that all BMS applications are created equal.
Reactive versus predictive BMS
Traditionally, OEMs have relied on a reactive approach to battery management that utilizes phenomenological measurements — measuring physical characteristics such as voltage or temperature — to gauge the state of a battery. To achieve optimal battery performance, a predictive approach based on electrochemical models is more effective. Predictive BMS improves upon each function of traditional BMS:
- Monitoring state of charge: Predictive BMS is able to achieve more accurate state-of-charge estimates by simulating the state of the cell’s lithium ions, enabling it to predict — instead of react to — physical changes, such as fluctuations in temperature.
- Reducing degradation: Predictive approaches are more effective at combating battery degradation, fighting common aging phenomena such as lithium plating and SEI thickening.
- Issuing anomaly alerts: Predictive BMS improves battery safety by identifying potential warning signs earlier, thus reducing incidents.
Containerized BMS offers flexibility
While BMS is sometimes implemented in a device on the battery pack itself, it does not have to be located there. Software containerization provides the flexibility to abstract BMS from the underlying hardware and run it anywhere — including on a centralized compute platform. A less sophisticated battery-monitoring integrated circuit can be located at the battery pack to gather data (usually voltage, current and temperature). It can then feed the data to the BMS, which would use the expanded processing and memory resources of the centralized compute to perform real-time analytics, thus achieving greater performance optimization and better integration with other vehicle systems.
As BMS evolves, a data-driven DevOps toolchain will enable the creation of a cloud-based digital twin of the vehicle. Algorithms will be able to leverage the experiences of other vehicles all over the world in a variety of driving scenarios to learn and help extend the life of EV batteries and the vehicles they power. Cloud connectivity will enable vehicles to utilize offboard processing power to run more powerful algorithms, allowing for the analysis of long-term vehicle data and the aggregation of fleet-level insights.
As the only provider of both the brain and the nervous system of the vehicle, Aptiv is uniquely positioned to deliver predictive BMS solutions that can optimize the performance of the battery and coordinate everything it interacts with, including the onboard charger, while meeting automotive functional safety requirements. Additionally, in 2022 Aptiv acquired Wind River, a leading provider of intelligent-edge software solutions, which provides a robust and flexible operating system to power Aptiv’s battery management software.
