Battery Insulation Diagnosis Using External High-Level Voltage
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Solution Overview
Problem
Current methods for diagnosing insulation conditions between battery packs and ground, such as those used in electric vehicles, lack accuracy due to reliance on pack voltage and do not effectively detect potential faults, posing risks of malfunction and electric shock.
Innovation Solution
An apparatus and method that apply a high-level DC voltage between the battery pack's positive or negative terminal and ground using a separate power supply, with a control circuit to measure current and calculate resistance, allowing for more accurate insulation condition diagnosis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only pack voltage is used for measuring insulation resistance, then the measurement system remains simple, but the diagnosis accuracy of insulation condition is low
Solution Approach 1:
The patent introduces a separate power supply as an intermediary device to apply high-level voltage for insulation measurement. This external power supply acts as a mediator between the measurement system and the battery pack, enabling accurate insulation resistance measurement without requiring the battery pack itself to provide the test voltage, thus resolving the contradiction between measurement accuracy and system simplicity
Solution Approach 2:
The patent changes the voltage parameter from using only pack voltage to applying a separate high-level voltage from an external power supply. This parameter change enables more accurate insulation resistance measurement by providing a controlled test voltage that is independent of the battery pack's operating voltage, thereby improving diagnosis accuracy
2Reliability
If insulation measurement uses only pack voltage, then the device structure remains simple, but the ability to detect potential faults is insufficient
Solution Approach 1:
The patent applies high-level voltage from a separate power supply before normal operation to perform preliminary insulation testing. This preliminary action allows potential insulation faults to be detected in advance under controlled test conditions, improving reliability by identifying issues before they cause malfunction or electric shock
Solution Approach 2:
The separate power supply serves as an intermediary that enables comprehensive insulation testing by providing a dedicated test voltage source. This intermediary device allows the system to perform thorough fault detection without complicating the battery pack's internal structure, as the testing function is separated from the power storage function
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
This approach enables more precise diagnosis of insulation conditions, reducing the risk of malfunction and electric shock by applying a high-level voltage and measuring current to determine resistance, thus identifying faults more accurately.
Implementation Method 1
a power supply and a controller operably coupled to the power supply. The power supply includes a first test port electrically connected to the positive terminal and a second test port electrically connected to the ground and is configured to generate a high-level voltage
Implementation Method 2
The controller is configured to record a current flowing through the first test port within the predetermined period from the first time point as a first test current. The controller is configured to diagnose the insulation condition between the battery pack and the ground, based on the first test current
Data Source
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AI summary
An apparatus and method for diagnosing an insulation condition between a battery pack and the ground, and a battery pack including the apparatus are provided. The apparatus includes a first resistor element electrically connected between a positive terminal of the battery pack and the ground; and a control circuit. The control circuit records a current flowing through the first test port as a first test current, while a high-level voltage is being applied between the positive terminal and the ground. The controller diagnoses the insulation condition between the battery pack and the ground, based on the first test current.