Battery Pack Connection Diagnosis Using Cell Voltage Convergence
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Solution Overview
Problem
Existing methods for testing electrical connections in battery packs fail to detect intermittent connections, which can lead to battery failures and downtime due to their partial conductivity.
Innovation Solution
A computer system that diagnoses electrical connections by measuring voltage drops or rises during discharge or charge events, identifying larger voltage differences between subsets of cells, and confirming convergence of voltages to detect intermittent connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact resistance measurements and pull force tests are used to assess connection quality, then connection quality can be evaluated, but intermittent connections cannot be detected
Solution Approach 1:
The system performs preliminary voltage measurements during normal charge/discharge operations before intermittent connections cause complete failures. By continuously monitoring voltage drops during regular pack operation, the system can detect emerging connection issues before they lead to battery failures or downtime.
Solution Approach 2:
The system implements feedback by comparing voltage measurements from different cell groups and using this information to detect intermittent connections. The voltage drop comparisons during charge/discharge cycles provide continuous feedback about connection health, enabling real-time detection of problematic connections.
2Reliability
If voltage drop measurements are taken during charge/discharge events, then intermittent connections can be detected, but additional measurement complexity is introduced
Solution Approach 1:
The voltage measurement system serves multiple functions: it monitors cell voltages for normal battery management, detects intermittent connections through voltage drop comparisons, and provides data for state of charge estimation. By making the measurement system multi-functional, the patent avoids adding dedicated complex hardware solely for intermittent connection detection.
Solution Approach 2:
The system uses the battery pack's own charge/discharge operations to generate the measurement conditions needed for detection. Normal operational currents create the voltage drops that reveal connection issues, eliminating the need for separate test equipment or external power sources for diagnostics.
3Loss of time
If voltage measurements are continuously monitored during operation, then intermittent connections can be detected in real-time, but energy consumption increases
Solution Approach 1:
The system performs voltage drop measurements periodically during charge/discharge events rather than continuously. By utilizing the natural periodic charge/discharge cycles of the battery pack, the system obtains detection opportunities without requiring continuous active measurement, thereby minimizing additional energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables detection of intermittent connections during operation, reducing downtime and prolonging the lifetime of electrical energy storage systems by providing accurate diagnostics and adjusting charging/discharge protocols.
Implementation Method 1
determine a voltage drop during a discharge event or a voltage rise during a charging event for at least a first subset and a second subset of the multiple of the electrical energy storage cells
Data Source
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AI summary
A computer system (100) for diagnosing an electrical connection within an electrical energy storage pack (108) comprising multiple electrical energy storage cells (110), the computer system comprises processing circuitry (102) configured to: determine a voltage drop (114a/b) during a discharge event or a voltage rise (116a/b) during a charging event for at least a first subset (106) and a second subset (107) of the multiple of the electrical energy storage cells (110), determine that the voltage drop (114a) for the first subset (106) of the electrical energy storage cells during the discharge event is larger than the voltage drop (114b) of the second subset (107) of electrical energy storage cells of the multiple electrical energy storage cells or that the voltage rise (116a) for the first subset (106) of the electrical energy storage cells (110) during the charging event is larger than the voltage rise (116b) of second subset (107) of multiple electrical energy storage cells, determine that the voltage of the first subset (106) of electrical energy storage cells converges with the voltage of the second subset (107) of electrical energy storage cells, and provide an output (120) that the first subset of electrical energy storage cells has an intermittent connection (113) to a voltage link (109a).