Battery Standby Diagnosis for Sensorless Leakage Current Detection
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Solution Overview
Problem
Conventional methods fail to accurately detect leakage current in battery systems without using a leakage current detection sensor, particularly when minute currents leak to power converters or occur due to ground failures.
Innovation Solution
A battery diagnosis apparatus and method that calculates power and temperature changes in a standby mode, using state of charge information and open-circuit voltage to determine leakage current without sensors, by comparing calculated power changes with expected discharge power and considering temperature and balancing control operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional battery diagnosis methods are used to detect leakage current, then measurement capability is limited, but measurement precision is insufficient for accurate leakage current detection
Solution Approach 1:
The battery is divided into multiple battery cells, and leakage current is measured for each cell separately. This segmentation allows precise detection of leakage current in individual cells while using a relatively simple measurement circuit, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
A control device is introduced as an intermediary to automatically control the connection between battery cells and the measurement device. This intermediary manages the complex measurement process, enabling precise leakage current detection without requiring the measurement device itself to be overly complex.
2Ease of operation
If battery diagnosis is performed with the battery connected to the vehicle, then diagnostic convenience is improved, but measurement accuracy deteriorates due to electrical noise from the vehicle
Solution Approach 1:
The measurement is performed periodically by temporarily disconnecting individual battery cells from the vehicle's electrical system. This periodic measurement approach allows accurate leakage current detection during brief isolation periods while maintaining overall operational convenience by quickly reconnecting cells afterward.
Solution Approach 2:
The control device preliminarily identifies which battery cell to measure and prepares the measurement circuit connection in advance. This preliminary action streamlines the measurement process, making it convenient to perform in-vehicle diagnostics while ensuring measurement accuracy through proper preparation.
3Productivity
If all battery cells are measured simultaneously for leakage current, then productivity is improved, but measurement accuracy deteriorates due to inability to isolate individual cell leakage
Solution Approach 1:
Instead of measuring all battery cells simultaneously, the system segments the measurement process to test each cell individually by controlling connections through the control device. This segmentation ensures accurate detection of leakage in each specific cell while maintaining reasonable diagnostic efficiency through automated cell-by-cell measurement.
Solution Approach 2:
The measurement system dynamically reconfigures connections between battery cells and measurement devices under control device management. This dynamic switching allows the system to efficiently cycle through multiple cells, providing both individual cell measurement accuracy and improved overall diagnostic productivity compared to static measurement approaches.
Data Source
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AI summary
An apparatus for diagnosing a battery located in a battery system including one or more batteries, the apparatus may include: at least one processor; and a memory configured to store instructions executed by the at least one processor to collect state of charge information of the battery when the battery system is in a standby mode; calculate an amount of power change of the battery during a maintaining period of the standby mode based on the collected state of charge information and pre-stored initial state of charge information; and compare the calculated amount of power change with an expected amount of discharge power of the battery and to determine whether a leakage current occurs in the battery system based on the comparison.