Surge Protector Deterioration Diagnosis Using Switched Voltage Monitoring
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Solution Overview
Problem
Existing surge protectors in secondary batteries lack effective methods to predict the failure of metal oxide varistors, leading to potential unprotected exposure to external surges due to the time difference between varistor instability and thermal disconnector contact changes.
Innovation Solution
A diagnostic apparatus and method involving a first and second switch to form closed circuits with diagnostic resistors, measuring diagnostic voltages across protection elements, and periodically assessing voltage changes to diagnose surge protector deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thermal disconnector (TD) is used to detect MOV failure, then the surge protector can indicate failure status, but there is a time delay between MOV instability and RC contact change
Solution Approach 1:
The diagnostic circuit performs preliminary detection of MOV deterioration by measuring voltage across the MOV before complete failure occurs. The processor continuously monitors the voltage signal from the diagnostic resistor, enabling early warning of MOV degradation and allowing preventive action before the thermal disconnector activates, thus eliminating the time delay in failure detection.
2Loss of information
If the RC contact is used to monitor MOV operation, then the failure status can be detected, but the user may not be aware of MOV failure until after it has occurred
Solution Approach 1:
The diagnostic circuit establishes a feedback mechanism where the processor continuously monitors the voltage across the MOV through the diagnostic resistor and provides real-time information about MOV health status. This feedback loop enables the system to detect deterioration trends and alert users before complete failure occurs, ensuring timely awareness and response to surge protection status changes.
3Reliability
If a diagnostic circuit with switches and resistors is added, then early detection of surge protector failure is enabled, but the device complexity increases
Solution Approach 1:
The diagnostic circuit is designed to share existing components in the surge protector system. The processor that already controls the thermal disconnector and RC contact is also used to measure diagnostic voltages. The diagnostic resistor is integrated into the existing circuit topology, allowing the same hardware to serve both protective and diagnostic functions, thereby minimizing the increase in device complexity while maintaining high diagnostic 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
Enables early detection of surge protector failures, ensuring timely protection against external surges by monitoring voltage changes through controlled circuit formations and threshold comparisons.
Implementation Method 1
measure a diagnostic voltage applied to the diagnostic resistor according to the opening and closing operations of the first switch and the second switch
Data Source
AI summary
An apparatus for diagnosing a surge protector connected to a battery includes a first switch configured to open and close a line that connects the first line to the second line by being directly connected to one end of each of the first line and the second line, a second switch configured to open and close a line that connects the second line to the third line by being directly connected to one end of each of the second line and the third line, and a processor configured to control opening/closing operations of the first switch and the second switch, measure a diagnostic voltage applied to the diagnostic resistor according to the opening/closing operation of the first switch and the second switch, and diagnose the surge protector based on the diagnostic voltage. A corresponding method and non-transitory computer-readable medium are also disclosed.