Battery Management Voltage Correction for Wiring Resistor Error
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Solution Overview
Problem
Existing battery management systems (BMS) face challenges in accurately measuring battery cell voltages due to voltage errors caused by wiring resistors in the electrical connection paths, which affect the efficiency of balancing operations.
Innovation Solution
The BMS includes a processor that measures a first cell voltage and corrects it using stored resistance values of wiring resistors to estimate an actual cell voltage, applying correction factors to account for voltage drops and adjust balancing switch duty cycles based on resistor values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage measurement is performed directly through wiring resistors in the electrical connection path, then the measurement process is simple, but voltage measurement accuracy deteriorates due to voltage drops across the wiring resistors
Solution Approach 1:
The resistance values of the wiring resistors are measured and stored in advance before actual battery cell voltage measurements are performed. This preliminary measurement of the wiring resistor characteristics enables subsequent compensation calculations to accurately determine the battery cell voltage by subtracting the voltage drop across the wiring resistors from the terminal voltage measurements.
2Productivity
If balancing operations are performed using uncorrected voltage measurements, then the balancing control is simple to implement, but balancing efficiency deteriorates due to inaccurate voltage data
Solution Approach 1:
The system continuously monitors the terminal voltages of battery cells, compensates for wiring resistor voltage drops using stored resistance values and measured currents, and uses the corrected voltage information to control the balancing operations. This feedback mechanism ensures that balancing decisions are based on accurate battery cell voltage data, improving balancing efficiency.
3Measurement precision
If correction factors are applied to compensate for wiring resistor effects, then voltage measurement accuracy is improved, but calculation complexity increases
Solution Approach 1:
Correction factors or resistance values of the wiring resistors are measured and stored in advance in the memory of the battery management system. During normal operation, the system retrieves these pre-stored values and combines them with real-time current measurements to calculate voltage drops, rather than performing complex iterative calculations during each measurement cycle.
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 improves voltage measurement accuracy and balancing efficiency by accurately estimating cell voltages and compensating for wiring resistor effects, ensuring precise control and protection operations.
Implementation Method 1
the processor is configured to calculate a voltage drop amount due to a current flowing in the electrical connection path based on the resistance value of the wiring resistor stored in the memory and to add the calculated voltage drop amount to the first cell voltage to remove the voltage error
Data Source
AI summary
A battery management system (BMS) including a memory in which a resistance value of a wiring resistor of an electrical connection path between a battery cell and the BMS is stored, and a processor configured to measure a first cell voltage of the battery cell and to remove a voltage error due to the wiring resistor reflected in the measured first cell voltage based on the resistance value of the wiring resistor stored in the memory to estimate a second cell voltage that is an actual voltage of the battery cell.