Battery Cell Voltage Sensing With Dynamic ADC Range Adjustment
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Solution Overview
Problem
Existing battery devices face challenges in detecting closed circuit voltage, which can become undetectable due to variations in battery cell quality and internal resistance, leading to inaccurate SOC estimation and potential faults.
Innovation Solution
A battery device with a storage unit, calculation unit, level shifter, and AD conversion unit that stores battery information, sets an acquisition range for closed circuit voltage, and converts it into a digital signal, dynamically adjusting the range to prevent undetectability by narrowing or expanding it as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed acquisition range is used for closed circuit voltage, then the device complexity is reduced, but the measurement precision deteriorates when voltage varies outside the fixed range
Solution Approach 1:
The patent implements a dynamic acquisition range adjustment mechanism where the calculation unit automatically changes the voltage acquisition range based on detected battery cell voltage levels. When voltage exceeds the fixed range, the system dynamically expands or shifts the range to maintain accurate measurement, resolving the contradiction between fixed-range simplicity and variable-range precision.
2Measurement precision
If the acquisition range is expanded to cover all possible voltage values, then the measurement precision is maintained, but the quantization errors increase
Solution Approach 1:
The system dynamically adjusts the acquisition range to match the actual voltage levels being measured, ensuring the ADC operates with optimal resolution for the current voltage range. This prevents quantization errors that would occur with a fixed wide range while maintaining measurement precision across varying battery conditions.
Solution Approach 2:
The patent changes the acquisition range parameter based on detected voltage conditions, allowing the system to optimize the voltage-to-digital conversion process. By adjusting the range parameter dynamically, the system maintains high measurement precision without introducing excessive quantization errors.
3Reliability
If the closed circuit voltage is monitored continuously, then the reliability of SOC estimation is improved, but the device complexity increases due to range adjustment mechanisms
Solution Approach 1:
The patent implements a feedback mechanism where the calculation unit continuously monitors closed circuit voltage and automatically adjusts the acquisition range based on the monitored values. This feedback loop ensures reliable SOC estimation while keeping the adjustment mechanism integrated within the existing control unit, minimizing additional device complexity.
Data Source
AI summary
A battery device has a storage unit, a calculation unit, a level shifter, and an AD conversion unit. The storage unit stores battery information including a closed circuit voltage of a plurality of battery cells electrically connected to each other. The setting unit that sets an acquisition range of the closed circuit voltage based on the battery information. The level shifter and the AD conversion unit convert the closed circuit voltage into a digital signal within the acquisition range set by the calculation unit. The calculation unit changes the acquisition range when the closed circuit voltage is outside the acquisition range.