Battery Management System Voltage Measurement Error Correction
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Solution Overview
Problem
Voltage measurement errors in battery cell management systems accumulate due to low impedance bus bar connections, leading to inaccuracies in SOC calculations and reduced battery pack capacity and cycle-life.
Innovation Solution
A battery management system that includes cell groups connected in parallel between bus bars, measurement terminals for cell voltage and error voltage measurement, and a battery management unit to calculate corrected cell voltage by accounting for bus bar resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If bus bar impedance is reduced to minimize voltage drop, then power loss is reduced, but measurement accuracy of battery cell voltage deteriorates due to accumulated errors in multi-cell systems
Solution Approach 1:
The patent introduces measurement terminals as intermediary elements that are directly connected to battery cells, bypassing the bus bar impedance path. These terminals serve as mediators to acquire voltage signals without the interference of bus bar resistance, thereby eliminating the accumulation of voltage measurement errors in multi-cell battery systems while maintaining low bus bar impedance for power efficiency.
2Productivity
If bus bar impedance is reduced to improve charging/discharging efficiency, then power transmission is improved, but SOC calculation accuracy deteriorates due to voltage measurement errors
Solution Approach 1:
The measurement terminals act as intermediary connection points that directly interface with battery cells, providing accurate voltage measurement paths independent of bus bar impedance. This allows the bus bar to maintain low impedance for efficient power transmission while the measurement terminals ensure accurate voltage readings for SOC calculation.
Solution Approach 2:
The patent segments the measurement function from the power transmission function by introducing separate measurement terminals. The bus bar remains dedicated to low-impedance power transmission, while the measurement terminals provide high-precision voltage sensing paths, allowing both functions to optimize their respective performance without compromise.
3Device complexity
If standard measurement terminals are used on bus bars, then device complexity is minimized, but voltage measurement accuracy deteriorates due to impedance-induced voltage drops
Solution Approach 1:
The patent introduces measurement terminals as intermediary components that directly connect to battery cells, providing accurate voltage measurement without requiring complex compensation algorithms. This simple structural addition eliminates measurement errors caused by bus bar impedance while maintaining minimal 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
Improves measurement accuracy of battery cell voltages, enabling better monitoring and control of battery packs, thereby enhancing efficiency and extending cycle-life.
Implementation Method 1
the impedance of the bus bar causes a voltage drop due to a battery current
Implementation Method 2
voltage drop measuring unit configured to measure an error voltage corresponding to a resistance value of the first bus bar
Data Source
AI summary
The present invention relates to a battery management system, which includes: at least one cell group configured to include first and second battery cells connected in parallel between first and second bus bars; a plurality of first and second measurement terminals positioned on the first and second bus bars; a plurality of third and fourth measurement terminals positioned at positions on the first bus bar, which correspond to one of ends of each of the first and second battery cells, respectively; a cell voltage measuring unit configured to measure a cell voltage of the cell group by using the first and second measurement terminals; a voltage drop measuring unit configured to measure an error voltage corresponding to a resistance value of the first bus bar by using the third and fourth measurement terminals; and a battery management unit configured to calculate a corrected cell voltage by using the cell voltage and the error voltage.