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Importance of Design Validation and Testing for BMS
Sep 28, 2023
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Why Design Validation and Testing is Critical for Battery Management Systems (BMS)?
Raja Ramachandran
Manager - DVT
Electric vehicles (EVs) have revolutionized the automotive industry with their promise of environmentally friendly transportation. The shift towards EVs introduces new challenges, especially in testing and validating battery management systems (BMS).
The journey towards efficient BMS testing begins during the specification and development stages. Simultaneously identifying verification activities allows designers to ensure that specifications are verifiable. Test engineers can then create detailed test plans and procedures, maintaining flexibility to accommodate specification changes. This parallel process aids in early issue identification, ensuring that the design meets user requirements.
How does the V model enhance the testing process?
The V-Model, also known as the Validation and Verification Model, is a software development and testing framework that enhances the testing process by emphasizing the importance of testing throughout the entire software development lifecycle. It is called the “V-Model” because its graphical representation resembles the letter “V.
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Enhances Quality:
From the outset, the V-model guarantees quality integration into the development process, reducing code defects and creating high-quality software.
Mitigates Risks:
The V-model establishes a well-defined path for the entire development process, enabling improved management and reduction of risks.
Boosts Efficiency:
The V-model promotes collaboration among various teams and stakeholders, resulting in more efficient development and testing procedures.
Facilitates Communication:
Prioritizing stakeholder communication, the V-model ensures everyone understands the requirements and objectives.
Strengthens Testing: The V-model emphasizes comprehensive and effective testing throughout development.
Enhances Documentation:
At each stage of development, the V-model mandates thorough documentation, leading to improved record-keeping and simplified code maintenance.
Image Source: Researchgate
Planning
Efficient verification planning is an ongoing process throughout the project lifecycle. Collaborating with development teams, the verification plan undergoes continuous refinement as design inputs evolve. Comprehensive documentation of the software or system under test helps outline the scope. A well-crafted test plan is a crucial milestone, mitigating project risks and enhancing productivity.
Developing
Test case development parallels the software development life cycle (SDLC) methodology. During this phase, precise design inputs are crafted, incorporating unambiguous and verifiable verification activities. Employing sequential testing of similar concepts reduces verification time and optimizes output utilization. Traceability links establish connections between test cases and corresponding design inputs, ensuring comprehensive coverage.
Execution
Execution of meticulously developed test procedures follows the test plan’s guidelines. Adherence to the plan is crucial to maintaining verification accuracy. Documenting deviations, invalid results, or modifications is vital for future reference. Defect identification and logging are integral during this stage, capturing and addressing issues early. A tractability matrix confirms that all design inputs outlined in the verification test plan have undergone testing, culminating in a pass ratio determination.
Reports
Verification execution’s culmination involves generating comprehensive reports summarizing the results and findings. These reports encapsulate design verification details, including configuration management, test outcomes, and identified issues. Design verification traceability reports establish connections between requirements and corresponding test results, guaranteeing comprehensive coverage. Any non-conformances are documented for proper resolution. The verification activity is concluded with reviews and approvals, ensuring adherence to quality standards.
Challenges in BMS Integration with Battery Pack
Electric vehicles’ battery pack designs present unique testing and validation challenges as they gain prominence. Battery packs store and can release much higher energy for short periods, demanding rigorous safety measures to prevent hazardous events. Thermal runaway events are no alien to the industry. The role of the BMS is to enhance the maximum use of battery and its safety, making BMS testing a critical aspect of EV development.
Components Inside an EV Battery Pack
Battery packs are composed of intricate mechanical and electrical systems. Cells and modules, safety components and contactors, temperature, voltage, current sensors, and a battery management unit (BMU) constitute the key components. Modules, incorporating cells and sensors, contribute to efficient assembly, monitoring, and safety. Safety components include fuses, interlock circuits, and relays, ensuring operational safety. Sensors enable accurate voltage, temperature, and current monitoring, facilitating BMU operation.
Battery Management System (BMS) Functionality
Battery Management System (BMS) is crucial in managing and safeguarding performance, health, and safety, including State of Charge (SOC) and State of Health (SOH), continuous monitoring, and diagnostics.
The BMS serves as the electronic brain of the battery pack, overseeing its performance and safety. It monitors cell voltage, temperature, state of charge, and health, making crucial decisions to ensure optimal performance. The BMS also communicates with external systems, providing data for vehicle operation. A distributed topology, often using CAN communication, facilitates BMS functions.
Testing Strategies for EV Battery Packs
Battery packs are complex assemblies that require a systematic approach to ensure their reliability and safety. One valuable tool is Design Failure Mode and Effects Analysis (DFMEA).
DFMEA is a methodical approach to identify and mitigate potential risks introduced in a new or changed product or service design. When applied to EV battery packs, DFMEA is a comprehensive framework for addressing design functions, failure modes, and their effects on the product and the customer.
Moreover, testing EV battery packs necessitates a strategic approach, considering the complexity of the assembly. The testing process encompasses BMS development, pack development, module production, and pack production stages.
BMS Development Testing involves Hardware-in-the-Loop (HIL) testing, simulating real-world conditions. This phase ensures the BMS responds as intended, identifying potential failures before implementation.
Pack Development Testing validates the assembly’s performance under various environmental stresses, such as temperature cycling and vibration, ensuring reliability under diverse conditions.
Module Production Testing focuses on robustness and current handling, verifying proper cell connections, balancing, and monitoring sensor accuracy.
Pack Production Testing, performed at the end of the assembly line, encompasses comprehensive tests to verify proper functioning, including high voltage interlocks, safety systems, and BMS communication.
Efficient Testing Solutions
Off-the-shelf testing solutions, such as charge/discharge cycles, cater to standardized testing requirements. However, customized, modular approaches offer flexibility and cost-effectiveness. The DMC Battery Testing Platform exemplifies this approach, integrating proven hardware and software to create tailored, automated test systems.
Efficient testing and validation of BMS for electric vehicle battery packs are paramount to ensuring EVs’ safety, reliability, and performance. Manufacturers can accelerate EV development by following structured processes, identifying key testing points, and leveraging advanced testing platforms while adhering to rigorous quality standards.
AMP BMS
Our Battery Management System (BMS) is an innovation designed to unlock maximum driving range. Its solid-state architecture delivers substantial current and power capabilities while reducing system costs. Our BMS solutions are characterized by exceptional flexibility, configurability, and scalability, tailored precisely to meet our clients’ unique specifications. By applying our proprietary BMS algorithms and software, we achieve unparalleled battery optimization while reducing development expenses and addressing the needs of low-voltage (LV) and high-voltage (HV) BMS requirements.
The testing process for our BMS encompasses multiple stages, beginning with Hardware-in-the-Loop (HIL) testing during BMS development to simulate real-world conditions and identify potential failures. Subsequently, during pack development testing, the BMS’s performance is validated under diverse environmental stresses to ensure its reliability. Module production testing focuses on robustness, current handling, and monitoring sensor accuracy, while pack production testing at the assembly line verifies proper functioning, including safety systems and BMS communication.
ABOUT AMP
With its perfect blend of software and hardware, AMP is revolutionizing electrification. Headquartered in Los Angeles, with offices in Detroit, Bengaluru, and Shanghai, AMP is a global leader in energy management solutions for e-mobility. Since 2017, AMP has advanced battery management technology, through industry-leading software and hardware. AMP continues to push mobility further from intelligent battery management platforms to robust fast-charging systems and complete cloud solutions for e-mobility.
To learn more, visit AMP at www.amp.tech and follow on LinkedIn@amp-energy-management.
