BMS Circuit Board Capacitor Open-Fault Detection by Voltage Timing
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Solution Overview
Problem
Current automated optical inspection methods cannot accurately detect open-circuit faults in capacitors mounted on circuit boards within battery management systems.
Innovation Solution
An apparatus and method that utilize a voltage source, voltage sensors, and a control unit to apply a test voltage and analyze diagnosis voltages across capacitors, determining open-circuit faults based on elapsed time for the voltages to reach a threshold, allowing for detection of faults in capacitors without imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If automated optical inspection (AOI) is used to inspect mounted components, then inspection speed is improved, but detection accuracy of capacitor open-circuit faults deteriorates
Solution Approach 1:
The patent replaces the optical inspection system with an electrical measurement system. Instead of using cameras and image processing to detect capacitor faults, the invention applies test voltages and measures electrical responses (currents or voltages) at test points to determine open-circuit conditions. This substitution of optical detection with electrical measurement resolves the contradiction by achieving both fast inspection speeds and high detection accuracy for capacitor faults.
2Measurement precision
If electrical testing methods are implemented, then detection accuracy of capacitor faults is improved, but device complexity increases
Solution Approach 1:
The patent segments the capacitor bank into individual capacitors by applying test voltages to specific test points and measuring responses at designated locations. The control unit divides the detection task into discrete measurement steps, testing each capacitor independently through controlled voltage application and current measurement. This segmentation approach maintains detection accuracy while managing system complexity through structured, modular testing procedures.
Solution Approach 2:
The testing apparatus is designed with multi-functionality to reduce overall complexity. The voltage source can apply different test voltages to different test points, and the measurement unit can measure responses at various locations. The control unit orchestrates these operations to detect faults in multiple capacitors using a single integrated system, rather than requiring separate dedicated testers for each capacitor, thus reducing device complexity while maintaining high detection accuracy.
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
Accurately detects open-circuit faults in capacitors on circuit boards without imaging, enabling efficient fault detection in battery management systems.
Implementation Method 1
a voltage source configured to selectively generate a test voltage... The control unit is configured to command the voltage source to apply the test voltage onto the third test point
Implementation Method 2
a first voltage sensor configured to detect a first diagnosis voltage generated between the first test point and the fourth test point, a second voltage sensor configured to detect a second diagnosis voltage generated between the second test point and the fourth test point
Implementation Method 3
a first capacitor; a second capacitor... determine whether at least one of the first capacitor and the second capacitor has an open-circuit fault based on at least one of the first diagnosis voltage and the second diagnosis voltage
Data Source
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AI summary
Provided is an apparatus and method for testing a circuit board included in a battery management system. The circuit board includes a first test point connected in common to one end of a first resistor, one end of a first capacitor and one end of a second resistor; a second test point connected in common to the other end of the second resistor and one end of a second capacitor; a third test point connected to the other end of the first resistor; and a fourth test point connected in common to the other end of the first capacitor and the other end of the second capacitor. The apparatus determines an open-circuit fault of at least one of the first capacitor and the second capacitor based on a first diagnosis voltage between the first and fourth test points and a second diagnosis voltage between the second and fourth test points.