Technicians assess the battery’s health using specialized diagnostic tools to check for capacity, voltage, and overall performance.
Visual Inspection
Physical Damage:
Check for any signs of physical damage, such as dents, swelling, or leaks.
Corrosion:
Look for signs of corrosion on terminals and connections.
Diagnostic Tools:
Use specialized diagnostic software and tools to gather data on the battery’s performance metrics.
Capacity Testing:
Measure the battery’s current capacity compared to its original specifications. This can involve fully charging and then discharging
the battery to determine its usable capacity.
Voltage and Current Measurement:
Check the voltage of individual cells and modules to identify any imbalances. Cells with significantly lower voltages may indicate degradation. Monitor current draw during charging and discharging cycles.
Internal Resistance Testing:
Measure the internal resistance of individual cells. Higher resistance can indicate aging or degradation, affecting performance and efficiency.
Cycle Count Assessment:
Analyze the number of charges cycles the battery has undergone. Higher cycle counts typically correlate with reduced capacity and efficiency.
Thermal Imaging:
Use thermal imaging to detect hot-spots during charging and discharging, which can indicate cell failure or degradation.
Data Analysis:
Review historical data, such as charging patterns and performance over time, to assess how the battery has been used and its overall health.
Battery Management System (BMS) Review:
Evaluate the functionality of the BMS, which monitors cell voltages, temperatures, and overall battery health.
Data Analysis:
Analyze historical data, such as charge cycles and usage patterns, to determine the battery’s life-cycle and potential issues.
Historical Performance Data
Charge Cycles:
Analyze the number of complete charge and discharge cycles the battery has undergone. More cycles generally indicate greater wear and reduced capacity.
Depth of Discharge (DoD):
Evaluate how deeply the battery has been discharged during use. Frequent deep discharges can accelerate degradation.
Capacity Trends:
Compare current capacity metrics against the original specifications to track performance degradation over time. Identify patterns in capacity loss, which may help predict future performance.
Voltage Data:
Review historical voltage readings of individual cells and modules. Look for trends in voltage drop or fluctuations that might indicate issues. Analyze the state of charge (SoC) data to understand how well the battery is performing across its range.
Temperature Data:
Monitor temperature readings during charging and discharging cycles. Consistent overheating can suggest problems with individual cells or the battery management system (BMS). Analyze thermal performance over time to identify any potential hot-spots or cooling issues.
BMS Logs:
Evaluate logs from the battery management system to assess cell balancing, charging rates, and any error codes or alerts that have been logged. Identify any anomalies or recurring issues that may need to be addressed.
Usage Patterns:
Assess how the battery has been used, including typical driving conditions, frequency of fast charging, and environmental factors (e.g., extreme temperatures). Understanding the usage context can provide insights into why certain performance characteristics are observed.
Comparison with Manufacturer Data:
Compare the evaluated data against manufacturer specifications and industry benchmarks to determine if the battery is performing within acceptable limits.
Predictive Modelling:
Use statistical models or machine learning techniques to predict future performance based on historical data. This can help anticipate when a battery might need replacement or re-manufacturing.
Disassembly:
Carefully disassemble the battery pack to access individual cells and modules. This step requires specialized tools and safety precautions due to the high voltage involved.
Cell Inspection and Testing:
Inspect individual cells for damage, swelling, or other defects. Cells that do not meet performance standards are typically replaced.
Test remaining cells for capacity and internal resistance.
Reconditioning or Replacement:
Reconditioning: Some cells may be reconditioned to improve performance, depending on their condition.
Replacement: Damaged or low-performing cells are replaced with new or refurbished cells that match specifications.
Reassembly:
The battery pack is reassembled with the inspected, reconditioned, or replaced cells. All components, including the battery management system (BMS), are reconnected and tested.
Testing and Calibration:
After reassembly, the battery undergoes extensive testing to ensure safety and performance standards are met.
Calibration of the BMS is crucial to ensure proper monitoring and balancing of the cells.
Quality Control:
Final checks are performed to ensure the battery meets manufacturer specifications and safety standards before being returned to service.
