Battery Cell Balancing Circuit Open Fault Detection
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Solution Overview
Problem
Existing battery systems fail to detect open circuit conditions in cell balancing circuits due to similarities in cell voltage readings under normal and open circuit conditions, making it difficult to differentiate between the two.
Innovation Solution
Incorporating first and second resistors with different resistance values in cell balancing circuits to pre-bias cell voltage inputs, allowing a microcontroller to determine open circuit conditions by comparing measured voltages against threshold values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cell voltage is measured through a cell balancing circuit with physical circuit hardware limitations, then cell voltage values can be read by the microcontroller, but open circuit conditions cannot be detected because the read values are similar to normal cell voltage values
Solution Approach 1:
The patent applies parameter changes by utilizing resistors with different resistance values (first resistance greater than second resistance) in different cell balancing circuits. This creates distinct voltage divider ratios that pre-bias the cell voltage inputs to different known values. When an open circuit occurs, the microcontroller can detect the anomaly by comparing the measured voltages against expected patterns, enabling reliable open circuit detection while maintaining accurate cell voltage measurement.
2Reliability
If resistors with different resistance values are used in cell balancing circuits to pre-bias cell voltage inputs, then open circuit conditions can be detected, but circuit complexity increases
Solution Approach 1:
The patent implements universality by designing cell balancing circuits where resistors serve dual functions: they provide the balancing function during normal operation and simultaneously enable open circuit detection through their specific resistance values. The same physical components (resistors, transistors, sense lines) are used for both cell balancing and fault detection, eliminating the need for separate detection hardware and reducing overall system complexity.
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
Effectively detects open circuit conditions in cell balancing circuits by utilizing the resistance pattern to differentiate between normal and open circuit scenarios, enhancing fault detection and system reliability.
Implementation Method 1
the microcontroller utilizes resistors (129, 229, 329) having a specific resistance pattern (e.g., resistor 129 has a different resistance than 229, and resistor 229 has a different resistance than resistor 329) to detect open circuit conditions in the cell balancing circuits (31, 32, 33)
Data Source
AI summary
A battery system includes a first cell balancing circuit electrically coupled to first and second sense lines and to a first battery cell. The battery system includes an integrated circuit measuring a first cell voltage between first and second sense lines at a first time while a first cell balancing circuit is turned off, and a second cell voltage between second and third sense lines at the first time while the second cell balancing circuit is turned off, and determining first and second cell voltage values based on the first and second cell voltages, respectively. A microcontroller receives the first and second cell voltage values and determines that an open circuit condition exists in the first balancing circuit if the first cell voltage value is greater than a first threshold voltage value, or the second cell voltage value is less than a second threshold voltage value.