Cell Balancing Circuit Abnormality Diagnosis
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Solution Overview
Problem
Existing methods for diagnosing abnormalities in cell balancing circuits are inefficient, requiring additional circuit configurations and comparators, leading to increased manufacturing costs and inability to accurately identify the cause of abnormalities across multiple cell balancing circuits.
Innovation Solution
An apparatus and method that utilize a diagnosis resistor and voltage sensing circuit to calculate inter-node voltage differences, determining abnormalities by analyzing changes in these differences between cell balancing circuits, with a control unit classifying circuits into groups and using a diode to limit reverse voltage application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate diagnosis circuit with additional comparators is installed at each battery cell to detect abnormalities, then the ability to detect abnormalities in the cell balancing circuit is improved, but the manufacturing cost and device complexity increase
Solution Approach 1:
The patent combines the diagnosis function with the existing cell balancing circuit by reusing the discharge resistor and switching element. The same physical components serve dual purposes: cell balancing operation and abnormality diagnosis, eliminating the need for separate diagnosis circuits and comparators at each cell
Solution Approach 2:
The discharge resistor and switching element in the cell balancing circuit are made multi-functional by enabling them to perform both their original cell balancing function and the additional function of abnormality detection. The control unit selectively activates these components for different purposes based on operational mode
2Measurement precision
If traditional diagnosis methods are used, then individual cell abnormalities can be detected, but the ability to identify the correct cause of abnormalities across multiple cell balancing circuits is insufficient
Solution Approach 1:
The patent segments the battery pack into multiple groups based on the connection positions of cell balancing circuits. By applying different control strategies to different groups and analyzing the patterns of voltage changes across groups, the system can identify whether an abnormality is localized to a specific circuit or affects multiple circuits, thereby determining the correct cause
Solution Approach 2:
The control unit measures voltage values during cell balancing operations and uses this feedback information to diagnose abnormalities. By monitoring voltage changes before and during switching operations and comparing expected versus actual behavior, the system can accurately identify the cause of abnormalities across multiple circuits
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 allows for more accurate and cost-effective diagnosis of abnormalities in cell balancing circuits, reducing false positives and identifying issues correctly across multiple circuits.
Implementation Method 1
a voltage sensing circuit to output a voltage corresponding to a voltage difference between the high potential node and the low potential node
Implementation Method 2
a diode to limit the application of voltage in reverse direction
Data Source
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AI summary
Disclosed is an apparatus and method for diagnosing an abnormality in a cell balancing circuit in a battery pack including a plurality of cells corresponding to each cell balancing circuit. The present disclosure turns off cell balancing switches included in a cell balancing circuit to be diagnosed and an adjacent cell balancing circuit among the cell balancing circuits. Also, the present disclosure stores a voltage value between nodes of the cell (hereinafter referred to as a 'diagnosis voltage value') by turning on the cell balancing switch of the cell balancing circuit to be diagnosed. Also, the present disclosure calculates a difference value between adjacent cell voltage values (hereinafter referred to as a 'cell difference value') and a difference value between adjacent diagnosis voltage values (hereinafter referred to as a 'diagnosis difference value'). The present disclosure determine whether an abnormality is present in the cell balancing circuit by analyzing a change pattern of a difference value between the cell difference value and the diagnosis difference value (hereinafter referred to as a 'determination value').