Come along for Part 2 of our BMS Series! This week we’re exploring the BMS development process with a focus on Acculon’s BMS design & development process, providing more detail about the intersection between the specific requirements of your commercial or industrial application & the BMS that provides the brains of the entire system.
Contact: Betsy Barry
Communication Manager
706.206.7271
betsy.barry@acculonenergy.com
In this installment, we are going to focus on Acculon’s product development process with respect to creating a BMS, covering key aspects related to designing for safety, application requirements, and overall optimized performance. It is worth reiterating from last week’s discussion that the number one priority of any BMS is safeguarding the human operator of the equipment, machinery, or EV that is powered by a lithium-ion battery. Any well-designed BMS begins with safety, as it is much more efficient and less expensive to proactively design for safety rather than to reactively incorporate safety features once the design process is underway. Beginning with safety necessitates beginning with the application itself; thus, the commercial or industrial application is the centerpiece of the planning phase, creating a smooth transition to the design process.
The Development Process.
We ended last week’s discussion with a set of considerations accompanied by various questions that are critical when evaluating the core capabilities of a BMS. Many of those considerations and questions can be addressed with a thorough understanding of the application and its requirements and specifications. The BMS is specified around a core set of requirements identified during the application requirements review, including essentials such as Functional Safety. To accommodate diverse customer applications, scalability in terms of voltage, current, and capacity is prioritized during the design planning process. Additionally, the system should be architected to withstand demanding operating environments characterized by varying temperature, pressure, humidity, and electromagnetic interference (EMI) exposure levels. This foundational approach guarantees the BMS can adapt to evolving customer needs while maintaining a safe and robust performance and reliability across a wide range of applications and commercial/industrial market segments.
Acculon approaches customer-specific requirements by breaking down the problem into a set of core system requirements. These requirements cover attributes such as battery chemistry, capacity, current, and voltage without requiring fundamental changes to the core system architecture. By leveraging a modular approach and utilizing reference designs for key components, the BMS can be tailored to meet a diverse set of needs. This focus on modularity and reference designs streamlines development efforts, reduces costs, and accelerates time-to-market while ensuring product quality and reliability without sacrificing safety.
There are, however, several key considerations that impact the design for specific customer applications. For example, when considering the charging ecosystem, there are several questions that need to be addressed, such as: What type of chargers will be used? Will there be support for single or multi-charger configurations? Is there a need for communication between the device and the charger? Identifying and planning for these requirements in the system architecture is key to providing seamless integration into customer products.
Developing the System Architecture
The BMS system architecture is developed by dividing the core requirements into distinct subsystems. By grouping requirements based on similarities, our process prioritizes system functionality and efficiency, while also considering both physical and data interfaces, ensuring seamless integration and performance. Physical interfaces, such as wiring, power, and component placement and sizing, are optimized for scalability and accessibility. Similarly, data interfaces are designed to handle varying volumes and velocities while maintaining data integrity and redundancy. This architectural approach enables system scalability and adaptability, with a particular focus on customer-facing components to facilitate customization and seamless integration.
The most important aspect of choosing the right BMS begins with thoroughly understanding your commercial or industrial application’s requirements, making sure that the BMS is able to handle your specific voltage, current, & energy demands.
At Acculon, we develop our BMS to meet the specific safety, performance, & application requirements for our client’s needs.
The development process is an iterative interplay between system architecture and subsystem design. Once the core requirements are divided into subsystems, additional requirements can be defined for each specific subsystem. This detailed understanding paves the way for hardware component selection, where trade-offs between hardware and software implementations are carefully evaluated. To accelerate this process and explore design concepts efficiently, we employ a model-based design approach utilizing tools such as Simulink, ANSYS, and our custom data platform for data analysis and reporting. This powerful combination enables efficient design, simulation, and analysis, allowing for rapid iterative development of the system. By continuously refining the system architecture and subsystem designs, we optimize the BMS for performance, cost-effectiveness, and adaptability.
To ensure development efficiency and system flexibility, our BMS has three primary components. The Module Monitoring Unit (MMU) and Battery Management Unit (BMU) are designed to be common across almost any low-voltage application, whereas the Power Distribution Unit (PDU) is meant to be customizable to meet the specific needs of the application, highlighting the system’s adaptability. The MMU serves as the primary sensor interface, collecting critical data such as cell string voltages, module temperatures, module current, and total module voltage. It also implements cell balancing to optimize cell performance and health by ensuring uniform cell states. The BMU, acting as the system’s central intelligence, aggregates data from MMUs, executes safety protocols, calculates critical system parameters, and conducts communication via various protocols including CAN, RS-485. The PDU functions as both actuator and sensor hub, measuring pack-level parameters, controlling high-voltage components, and accommodating additional sensors as required by specific applications.
By carefully allocating requirements to these subsystems and iteratively refining their designs, the BMS is both robust and flexible. This approach enables us to efficiently address diverse customer needs while maintaining a high level of system performance and reliability. The points below highlight key features of our hardware and software design and testing processes, with an additional mention of our collaboration with external partners to ensure quality throughout design, prototyping, and testing.
Hardware Development
Our in-house electrical and electronics development and testing capabilities are essential to the successful realization of our BMS components.
Design:
- Component Selection: Rigorous component selection processes guarantee safety, compatibility, performance, and long-term reliability.
- Circuit and PCB Design: Critical components such as the MMU, BMU, and PDU, are designed and developed with a special focus on optimizing performance, reliability, and cost-effectiveness.
Testing:
- Functional Testing: Comprehensive functional testing verifies component behavior under various operating conditions, ensuring adherence to design specifications.
- Reliability Testing: Accelerated life testing and failure analysis are conducted to predict component lifespan and identify potential weaknesses.
- Safety Testing: Electrical safety testing is performed to ensure compliance with relevant safety standards and protect end-users.
Software Development
To ensure rigorous development and validation of BMS subsystems, we employ a model-based design (MBD) approach centered around Simulink.
Design:
- Simulink Requirements Toolbox: This is instrumental in managing and tracing software requirements throughout the development lifecycle. By linking requirements directly to Simulink models, we establish a clear and traceable relationship between system behavior and its intended functions.
Testing:
- Simulink Test: Leveraging Simulink Test, we generate comprehensive test cases derived from requirements, enabling thorough verification of subsystem performance. This automated test generation significantly enhances development efficiency and improves boundary condition coverage. Furthermore, Simulink Embedded Coder facilitates the seamless translation of Simulink models into production-quality code, which is then deployed to our Hardware-in-the-Loop (HiL) testing environment for rigorous validation under real-world conditions. This integrated MBD workflow ensures that software requirements are accurately implemented, tested, and verified, ultimately leading to a robust and reliable BMS system.
Collaboration with External Partners:
PCB Design and Fabrication: We partner with specialized PCB design and fabrication houses to ensure optimal board layout and production quality.
- Prototyping: External prototyping services are utilized to rapidly translate designs into physical hardware for initial evaluation.
- Environmental Testing: Components are subjected to rigorous environmental tests, including temperature extremes to assess their durability and robustness.
- EMC Testing: To ensure compliance with regulatory standards, we collaborate with accredited EMC testing laboratories for comprehensive evaluation.
By leveraging our in-house expertise and collaborating with external partners, we achieve an efficient and effective product development process. This approach allows us to focus on core competencies while accessing specialized capabilities for PCB design, prototyping, and EMC testing.
The most important aspect of choosing the right BMS for your system begins with a thorough understanding of your commercial or industrial application’s requirements, making sure that the BMS is able to handle the specific voltage, current, and energy demands of your system. Additionally, the BMS should be capable of providing the necessary safety features, such as overcharge protection, thermal management, and fault detection. It’s also crucial that the BMS integrates seamlessly with your existing system architecture, supporting communication protocols and data logging needs. By ensuring that the BMS is tailored to these critical parameters, you can optimize the performance, reliability, and lifespan of your battery-powered system, ultimately leading to reduced downtime and lower operational costs.
Next week, we will explore the next aspect of the development process, integrated system testing. Acculon relies on in-house testing capabilities via our world-class battery testing laboratory as a crucial step for ensuring product quality and reliability, as well as providing valuable insights for design optimization and risk mitigation. Plus, our testing lab is the heart of our testing and validation-centered research and development environment at Acculon, enabling our model-based approach to our BMS by leveraging over a decade of providing Tier 1 support to some of the world’s largest automotive and battery OEMs. So be sure to check out next week’s installment in the series. In the meantime, if you’d like to learn more about Acculon’s BMS, we invite you to download our spec sheet.