Battery Insulation Monitoring Circuit for Measurement Failure Detection
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Solution Overview
Problem
Existing insulation resistance detection apparatuses cannot detect insulation resistances when the measurement portion is broken down, posing a risk of electric shock from high voltage batteries used in electric vehicles.
Innovation Solution
A failure detection apparatus with a first switch connected to the positive electrode and a second switch connected to the negative electrode of a battery, along with detection resistances and a measurement circuit, which forms a failure-detection series-connected circuit by turning both switches on to detect failures based on measured voltage, allowing for the detection of measurement portion breakdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If one switch is turned on and the other is turned off to measure insulation resistance, then insulation resistance can be detected, but the measurement portion breakdown cannot be detected
Solution Approach 1:
The system performs a preliminary check by turning on both switches to verify the measurement portion is functioning before proceeding with insulation resistance measurement. This preliminary action detects measurement portion breakdowns preventively, ensuring reliable subsequent measurements.
Solution Approach 2:
The measurement process is segmented into two distinct operational modes: a failure detection mode where both switches are on to check measurement portion integrity, and a normal measurement mode where one switch is on and the other is off to measure insulation resistance. This segmentation allows independent verification of system health.
2Reliability
If both switches are turned on to detect measurement portion failure, then failure detection is enabled, but insulation resistance measurement becomes impossible
Solution Approach 1:
The system employs periodic action by alternating between failure detection mode (both switches on) and insulation resistance measurement mode (one switch on, one off). This periodic switching allows the system to regularly verify measurement portion health while maintaining the capability to perform insulation resistance measurements at appropriate intervals.
Solution Approach 2:
The switch states are made dynamic rather than static, allowing the system to transition between different operational configurations. The controller dynamically adjusts switch states based on the current operational phase, enabling both failure detection and insulation resistance measurement capabilities to be accessed as needed.
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 the detection of measurement portion failures, ensuring the insulation resistances of high voltage batteries can be accurately monitored, preventing electric shocks and ensuring safe operation of electric vehicles.
Implementation Method 1
a measurement circuit that measures a voltage of the detection resistances
Data Source
AI summary
A failure detection apparatus includes: a first switch configured to be connected to a positive electrode of a battery; a second switch configured to be connected to a negative electrode of the battery; detection resistances that are connected in series between the first switch and the second switch; and a measurement circuit that measures a voltage of the detection resistances, wherein (i) both the first switch and the second switch are turned on to form a failure-detection series-connected circuit consisting of the battery and the detection resistances, and (ii) a failure detection mode is provided to detect a failure based on the voltage measured by the measurement circuit.