Join us as we embark on a new series exploring everything to do with battery management systems (BMS). Today we’ll discuss what exactly a BMS is and what it does. Read on for a layperson’s, system-level introduction to the BMS!
Contact: Betsy Barry
Communication Manager
706.206.7271
betsy.barry@acculonenergy.com
The What: (What are we even talking about in the first place?)
Lithium-ion (Li-ion) and Sodium-ion (Na-ion) energy storage systems offer significant advantages for today’s high-demand commercial and industrial applications. High energy density, low self-discharge rate, fast charging, and extended battery life make Li-ion systems an attractive alternative to traditional systems like lead-acid. However, to achieve these advantages Li-ion systems require a Battery Management System, or BMS, to ensure the system remains safe and effective for the full life of the cells. In the next few paragraphs, we’ll look at the guiding principles and core functions of a BMS in an advanced energy storage system so that you can make better, safer choices when selecting a BMS for your specific system.
The Why: (Guiding principles)
Protecting the Human
The primary function of a BMS is to ensure the safety of the operator using the battery-powered system. Batteries, particularly used in high-demand applications like electric vehicles or industrial equipment, can be hazardous if not properly managed and maintained. A BMS monitors critical parameters such as voltage, current, and temperature. By doing so, it can detect and respond to potentially dangerous conditions, such as overheating or overcharging, thereby preventing accidents and ensuring user safety. Protecting the individual using the application is the number one priority of a BMS.
Safeguarding Battery Cells
Battery cells are susceptible to damage from a variety of abuse or failure scenarios. Over-charge, over-discharge, and exposure to extreme temperatures can significantly degrade battery performance and health. The BMS is constantly monitoring the state of each cell within the battery pack. In case of any anomalies, the BMS can take corrective actions, such as disconnecting the load or initiating cooling mechanisms, to protect the battery from damage.
Prolonging Battery Life
Under normal operating conditions, the longevity of a battery is a priority. Advanced battery systems are expensive. Replacing battery packs can be costly and inconvenient, especially in large-scale installations in industries like in construction or mining. The BMS plays a pivotal role in extending the battery’s life by ensuring that it operates within optimal limits. By balancing the charge across all cells and preventing conditions that could lead to premature degradation, the BMS helps extend the lifespan of the battery, maximize the usable energy and provide an optimal return on investment and reliability over time.
By monitoring critical parameters, safeguarding both human operators and battery cells, prolonging battery life, and maintaining functional requirements, the BMS is the brains of the entire advanced energy storage solution.
Maintaining Functional Requirements
For a battery pack to be effective, it must consistently meet its functional design requirements, which are dictated by the application for which the pack will be providing energy. This means that it must deliver the necessary power and performance as intended by its design. The BMS ensures that the battery remains in a state where it can fulfill these requirements. It should efficiently manage charging, balance the cells, and keep the battery pack in optimal condition, ensuring that it performs as expected throughout its operational life.
The How (BMS core functions)
Monitor, Analyze, React, Inform
For any Li-ion system, no matter how large or small, complex or simple, the primary function of the BMS is and must be safety. In order to keep cells safe, the BMS must be able to monitor cell, module, and pack conditions, analyze the current state of the battery, react in order to mitigate out-of-limit conditions, and inform the device and/or operator of any fault or failure conditions. Because the electrochemical reactions occur inside the cell, the BMS monitors the battery by using sensors to measure signals such as voltage, current, and temperature. The BMS analyzes these external signals and leverages model-based strategies to estimate the overall state of the battery system. If the battery is in an undesirable state, the BMS can react to the out-of-limit conditions by informing the application of a reduced operating condition or by disconnecting the battery from the rest of the system. The BMS will then inform the application and operator of any present fault or failure condition resulting in the reduced performance.
How do you choose a BMS for your battery system?
Conclusion
Hopefully, this primer has demonstrated why the BMS is indispensable for ensuring the safety, efficiency, and longevity of lithium-ion energy storage systems. By monitoring critical parameters, safeguarding both human operators and battery cells, prolonging battery life, and maintaining functional requirements, the BMS is the brains of the entire advanced energy storage solution. As we delve deeper into the process of designing an optimal BMS in our next installment, you’ll gain a deeper understanding of why a robust BMS is essential for today’s high-demand applications and how Acculon approaches the development process to meet systems’ requirements and exceed industry safety standards. Stay tuned for more insights in our continuing BMS series!