The rise in popularity of battery management systems (BMS) is undeniable, but it can be challenging. According to a Mordor Intelligence report, the BMS market will be nearly 12 billion dollars by 2029. The reason is relatively straightforward. As the industry grapples with sustainability, modes of transportation turn to electrical power sources, and renewable energies must store what they produce in batteries.
Even niche markets like industrial applications, medical devices, telecommunication, or data centers increasingly rely on batteries and their management systems for their operations. Hence, for many, understanding how a BMS works and how to design it is no longer optional.
What most people know about BMS
It’s complicated, and it’s about power
In essence, a battery management system monitors, among other things, the state of charge (SoC), meaning how much battery life the cells can still provide before being depleted, and the state of health (SoH), which represents the overall capacity of the battery compared to when it was new. However, many often underestimate the intricate nature of a great BMS.
Beyond tracking the SoC and SoH, a battery management system ensures the cells wear out evenly by distributing the charge and discharge cycles, thus ensuring a longer total lifespan. It also provides safety features, like disconnecting the battery to prevent a fire in case of a fault or switching to a different cell or pack when one fails.
Interestingly, while BMS can have a wide range of applications and offer complex features, many engineers approach their design with a set of very standard questions. In many instances, teams will determine things like the peak and average power consumption they hope to get out of their battery, the safety requirements of their industry, and the peripherals they will use to communicate with the host microcontroller, such as SPI or CAN. While these questions and considerations are necessary, we wanted to share three questions that too few ask at the early stages of development but are crucial when designing a BMS.
3 questions many forget to ask before they get started
1. How easy is it to daisy chain battery modules?
Connecting battery packs in a daisy chain is common yet often overlooked. In numerous instances, using multiple packs instead of a giant one can help reduce costs, provide redundancies, extend the overall lifespan, and more. However, connecting them in a daisy chain is quite the engineering challenge. The BMS must ensure that communication with all the cells is quick and safe.
That means providing a direct line with the cells and their sensors and electrically isolating the boards used in the daisy chain and the host MCU. Moreover, the reduced battery pack space creates a lot of challenges to place the electronics and the required sensors, e.g. temperature ones.
2. What BMS software features are already in the ecosystem?
Software developers know all too well that an ecosystem can make the application creation a breeze or a bust. Consequently, knowing what features are available out of the box is crucial. Indeed, too often, teams set a list of features, like SoC and SoH, but seldom ask how they will create an application that can rapidly and reliably implement these functionalities in software.
In many cases, a company can save a lot of time and resources when it adopts an ecosystem that offers these features ready or nearly ready out of the box. Put simply, a BMS is complex enough as it is without having to design everything from scratch.
3. How can I create a proof-of-concept in minutes?
A proof-of-concept can be a team’s best starting point because it provides a clear path to the final design. That’s why ST released the AEK-POW-BMS63EN, a development board that features our L9963E battery management IC. Additionally, we offer the AEK-COM-ISOSPI1, which helps isolate the connection to the host MCU like the SPC58 on the AEK-MCU-C4MLIT1 platform. ST even designed the AEK-POW-BMSHOLD to connect batteries to our development kits easily.
Hence, engineers can connect up to 31 packs in a daisy chain in a few minutes, set them up using an example application within AutoDevKit Studio, and experiment with all the software features.
How to get started
On top of putting a proof-of-concept together in minutes, users will also get to experiment with our graphical user interface, which will help them better understand notions like coulomb counting or cell balancing. Moreover, a Getting Started Guide can ensure teams get on the right track. Indeed, it’s easy to overlook the early stages of development when everyone is thinking about the final design. However, these first steps are critical for a company to reach production rapidly and efficiently. That’s why we don’t only provide a hardware and software platform but also the documentation to make this first step a breeze.
