1. How do physics-based models help improve the safety and reliability testing of batteries to meet mechanical requirements?
Current methods used to assess the battery system’s safety, performance, reliability, and lifetime are resource-intensive, involving destructive testing and costly infrastructure. In this regard, battery systems must withstand environmental vibration and shock conditions, requiring a mechanical assessment of the structural reliability of the battery module. To improve battery testing, physical testing is being substituted by simulation and physics-based models, including both numerical approaches like finite element modelling and analytical methods, are being applied. Key aspects such as shock and vibrational performance must be evaluated, as they influence the durability of the battery system. In particular, the most sensitive interfaces, connections, and joints are validated, considering factors such as the swelling effect and potential fabrication defects. This includes sensitive components such as laser-welded joints (e.g. terminals), which are prone to fatigue caused by vibration, requiring thorough validation for long-term reliability. Simulations provide useful information to make decisions during the design phase and make trial-and-error procedures much less resource-intensive.
2. How do you confirm that the models developed in the FASTEST project are both accurate and reliable, particularly when predicting battery performance and lifespan?
Physics-based simulations, particularly those based on the finite element method (FEM), play a crucial role in enhancing our understanding of the structural behaviour of battery systems. FEM models allow for detailed theoretical analysis of how these systems perform under various conditions. However, to ensure their accuracy and reliability, the results from FEM simulations must be validated against experimental data.
Mechanical testing of full battery modules offers valuable insights, yet such tests are often costly and resource-intensive. To achieve validation in a more cost-effective manner, small-scale or simplified versions of the battery system can be developed. These scaled-down tests can replicate key mechanical behaviours while reducing overall testing expenses.
Since the lifespan of battery modules is frequently constrained by the most vulnerable components—such as laser-welded joints, which are susceptible to vibration-induced fatigue—the validation effort can be concentrated on these critical areas. Testing at the coupon level, which involves smaller tailored test samples representative of these sensitive regions, can effectively reproduce local behaviours in terms of stiffness, strength, and areas of concentrated damage. This approach allows for targeted validation of the most failure-prone components, ensuring that the results remain representative of the module’s overall structural integrity, without the need for full-scale testing.
In conclusion, by combining physics-based simulations with focused experimental validation at the coupon level, it is possible to achieve reliable predictions about battery system behaviour while minimizing the costs associated with extensive module-level testing.
3. How do you ensure the accuracy and efficiency of the hybrid testing platform in the FASTEST project?
In the development of advanced battery management systems (BMS), it is essential to create robust verification and validation environments. These environments cover various scenarios, from Model-in-the-Loop (MIL) to Hardware-in-the-Loop (HIL), and provide a comprehensive framework for testing and validating BMS developments. We leverage this approach to ensure that the BMS performs optimally under various conditions, such as variations in temperature, load or ageing. The switch from MIL to HIL enables incremental validation, starting with virtual simulations and culminating in real-time hardware integration, which significantly improves the reliability and accuracy of the BMS.
In parallel, the lifecycle analysis of BMS developments from a safety and reliability perspective follows strict industry standards, such as IEC 61508 and ISO 26262. These standards guide the tool chain used throughout the development process, ensuring that each stage – design, implementation, testing and deployment – meets functional safety requirements. By adhering to these frameworks, we can identify and mitigate potential points of failure, assess risks and implement mechanisms to ensure that the BMS maintains security even under fault conditions. This holistic approach to validation and lifecycle management improves system robustness and ensures compliance with global security and reliability standards, laying the foundation for scalable and reliable BMS solutions.