Battery Management Cell Swapping for Fault-Tolerant Voltage Sensing
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Solution Overview
Problem
Existing battery management systems in electric and hybrid electric vehicles face challenges in accurately measuring battery cell voltages due to electromagnetic interference from vehicle components, leading to potential inaccuracies that affect battery longevity and performance, and existing redundancy measures increase circuit complexity and semiconductor area.
Innovation Solution
A battery management system with a secondary processing chain using a single ADC multiplexed over cells and a cell swapping mechanism to maintain accurate UV/OV detection and voltage measurement even in the presence of faults, reducing circuit complexity and semiconductor area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary processing chain with redundant ADCs is implemented to maintain accurate UV/OV detection in the presence of faults, then reliability is improved, but device complexity increases
Solution Approach 1:
A single ADC is designed to perform multiple functions: normal voltage measurement, fault detection, and swapped cell measurement. The ADC is multiplexed to measure different cell configurations based on operational needs, eliminating the requirement for separate redundant ADCs while maintaining detection reliability
Solution Approach 2:
The system uses its own existing ADC and measurement infrastructure to detect and respond to faults. When a fault is detected in a primary measurement path, the system automatically swaps to alternative cell configurations using the same ADC, making the system self-diagnosing and self-correcting without additional dedicated redundancy hardware
2Reliability
If a secondary processing chain with redundant ADCs is implemented to maintain accurate UV/OV detection in the presence of faults, then reliability is improved, but semiconductor area increases
Solution Approach 1:
A single ADC is designed to perform multiple functions: normal voltage measurement, fault detection, and swapped cell measurement. The ADC is multiplexed to measure different cell configurations based on operational needs, eliminating the requirement for separate redundant ADCs while maintaining detection reliability
Solution Approach 2:
The patent merges the functions of primary measurement and redundancy into a single ADC unit. The same hardware resource is shared between normal operation and fault tolerance modes through time-multiplexing, consolidating what would traditionally require separate physical components into one integrated unit
3Measurement precision
If differential voltage amplifiers with high CMRR are placed at each cell to improve measurement accuracy, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Multiple measurement functions (normal voltage measurement, differential measurement, and swapped cell measurement) are combined into a single ADC unit. The system uses one ADC to perform all measurement tasks by switching between different cell configurations, eliminating the need for separate measurement circuits for each function
Data Source
AI summary
A method can be used to control a battery management system. A first voltage drop is sensed between a first terminal of a first battery cell and a second terminal of the first battery cell and a second voltage drop is sensed between a first terminal of a second battery cell and a second terminal of the second battery cell. A faulty condition is detected in the first battery cell or the second battery cell based on the first voltage drop or the second voltage drop. The first voltage drop is swapped for a first swapped voltage drop between a common terminal and the second terminal of the second battery cell.