Battery Pack Capacitor Defect Detection Using Noise Signals
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Solution Overview
Problem
Existing battery pack systems lack an effective method to detect defects in capacitors, leading to inaccurate voltage measurement and potential issues such as overcharging or overdischarging, which can cause swelling, ignition, or explosion.
Innovation Solution
An apparatus and method that measures the capacitance of capacitors in a non-destructive manner by using a voltage measuring unit, a filter unit with a capacitor, a signal output unit, and a control unit to detect defects based on noise signals and preset reference values, allowing for accurate identification of capacitor issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a capacitor is included in the filter to filter high frequency current, then the voltage measurement accuracy is improved, but the reliability deteriorates due to undetected defects causing incorrect SOC calculation
Solution Approach 1:
The system performs preliminary defect detection of the capacitor by injecting a test signal and measuring the impedance before normal operation. This advance inspection identifies potential failures in the capacitor, allowing the system to switch to a bypass path or alert the user, thereby preventing reliability issues while maintaining voltage measurement accuracy through the filter during normal operation
Solution Approach 2:
A test signal injection unit and impedance measurement mechanism are introduced as intermediary components to detect capacitor defects. These intermediaries enable non-destructive testing of the capacitor by measuring its impedance characteristics without affecting the normal filtering function, thus resolving the contradiction between maintaining filter functionality and ensuring reliability
2Measurement precision
If the capacitor is tested by disassembling the battery pack, then the measurement precision is improved, but the ease of operation deteriorates and productivity decreases
Solution Approach 1:
The system performs preliminary capacitor defect detection while the battery pack remains assembled, using a test signal injection unit that can access the capacitor through existing circuit paths. This eliminates the need for disassembly while maintaining accurate impedance measurement, thus improving ease of operation without sacrificing measurement precision
Solution Approach 2:
The battery pack's existing voltage measuring unit and circuit paths are utilized to perform the capacitor defect detection itself, without requiring external specialized equipment or disassembly. The system uses its own resources to conduct the inspection, making the process simple and integrated into normal operation
3Reliability
If a defect detection system is added to the battery pack, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The voltage measuring unit serves dual purposes: it measures the battery voltage during normal operation and measures the impedance of the capacitor during defect detection by switching to a test signal mode. This multi-functionality adds reliability through defect detection capability while minimizing the increase in device complexity by reusing existing components
Solution Approach 2:
A switchable signal path is introduced as an intermediary mechanism that directs either normal voltage measurement signals or test signal injection through the same hardware components. This allows the system to add defect detection functionality without proportionally increasing complexity, as the same physical components serve multiple functions based on signal routing
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 easy detection of capacitor defects in assembled battery packs, reducing costs and providing users with information on degradation trends, thereby preventing potential battery-related problems.
Implementation Method 1
a filter unit having a capacitor provided to correspond to the battery cell and configured to filter a noise included in the voltage measured by the voltage measuring unit through the capacitor
Implementation Method 2
calculate a capacitance of the capacitor included in the filter unit in a non-destructive manner and detects a defect of the capacitor
Data Source
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AI summary
The present disclosure relates to an apparatus and method for detecting a defect of a battery pack, and more particularly, to an apparatus and method for detecting a defect of a capacitor provided in the battery pack. According to the present disclosure, since a defect of a capacitor is detected using a noise signal, the defect of the capacitor in an assembled battery pack may be easily detected. In addition, since the present disclosure includes a compact circuit structure for noise signal output, noise signal filtering and voltage measurement, the cost for detecting a defect of the capacitor may be reduced.