Battery Leakage Current Sensing Using Floating Capacitor
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Solution Overview
Problem
Conventional methods fail to accurately and simply sense leakage current in batteries, which can lead to unexpected discharge, malfunctions, and safety hazards in electric vehicles and other battery-powered devices.
Innovation Solution
A battery leakage current sensing apparatus using a floating capacitor, terminal selection switching unit, charge switching unit, polarity reverse switching unit, and leakage current determining unit to calculate leakage resistance and compare it with a criterion insulation resistance, with a simple circuit configuration and optional alarming functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods are used to sense leakage current, then the sensing can be performed, but the circuit configuration becomes complex and measurement accuracy is insufficient
Solution Approach 1:
The patent divides the voltage detection process into separate phases for cathode and anode terminals. The terminal selection switching unit separates the detection paths, allowing each terminal to be measured independently through sequential charging of the floating capacitor. This segmentation simplifies the overall circuit design while maintaining measurement accuracy for leakage current detection.
Solution Approach 2:
The patent employs preliminary charging of a floating capacitor with detection voltage before performing leakage current measurement. The charge switching unit pre-charges the capacitor with voltage from selected terminals through the terminal selection switching unit. This preliminary action stores the necessary voltage information in the capacitor, enabling accurate leakage current sensing without requiring complex real-time measurement circuits.
2Reliability
If leakage current sensing is implemented, then safety hazards can be detected, but unexpected discharge and malfunctions may still occur if detection is not early enough
Solution Approach 1:
The patent implements a feedback mechanism where the leakage current determining unit continuously monitors the voltage on the floating capacitor and compares it against threshold values. When leakage current is detected, the system provides feedback by activating an alarming unit to notify users. This continuous monitoring and feedback loop ensures early detection of safety hazards and enables timely response to prevent battery discharge and malfunctions.
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 leakage currents, preventing battery discharge, protecting against device malfunctions and safety risks, while reducing noise interference for more accurate sensing.
Implementation Method 1
a floating capacitor (C5) charged with a detection voltage output from one of the cathode (A) and anode (B) terminals of the battery (200)
Data Source
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AI summary
An apparatus for sensing a leakage current of a battery comprises a floating capacitor charged with a voltage detected from a cathode or anode terminal of a battery; a terminal selection switching unit for selecting a voltage detection path for the cathode or anode terminal; a charge switching unit for charging the floating capacitor with a detection voltage of the cathode or anode terminal, detected through the selected voltage detection path; a polarity reverse switching unit for reversing a polarity of the detection voltage of the anode terminal charged to the floating capacitor; and a leakage current determining unit for sensing the detection voltage of the cathode terminal charged to the floating capacitor and the polarity-reversed detection voltage of the anode terminal charged to the floating capacitor to calculate a leakage resistance, and comparing the calculated leakage resistance with a criterion insulation resistance to determine whether a leakage current occurs.