Battery Voltage Measurement Channel Calibration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing battery management systems face challenges in achieving high accuracy in voltage measurements due to errors in sampling capacitor values and conversion factors, which can lead to inaccuracies in state of charge (SoC) calculations and require larger, more costly systems.
Innovation Solution
Implementing a two-step channel calibration procedure within the battery management system, where each channel is connected to a reference voltage source to calibrate and correct for errors in sampling capacitor values and conversion factors, thereby reducing the need for high-voltage switches and minimizing the impact of capacitor voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high accuracy voltage measurement is pursued without calibration, then measurement precision requirements increase system complexity and cost, but calibration errors in sampling capacitor values and conversion factors still cause measurement inaccuracies
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements before actual voltage measurements. The system conducts a two-step calibration procedure where sampling capacitors are charged to known reference voltages, and conversion factors are determined in advance. These pre-determined calibration values are then used to correct subsequent measurements, eliminating the need for continuous high-precision components and reducing overall system complexity while maintaining measurement accuracy.
2Ease of manufacture
If traditional voltage measurement methods are used without channel calibration, then system design is simpler, but errors in sampling capacitor values and conversion factors lead to inaccurate SoC calculations
Solution Approach 1:
The patent implements feedback by using measured calibration data to correct subsequent voltage measurements. The system determines calibration factors through initial measurements against known reference voltages, then applies these factors to correct all subsequent cell voltage measurements. This feedback mechanism ensures accurate SoC calculations while maintaining a simple system design that uses standard components rather than requiring high-precision components throughout.
3Ease of operation
If standard voltage measurement channels are used without calibration, then implementation is more straightforward, but capacitor voltage variations impact measurement accuracy
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting measurement parameters based on calibration data. The system changes the operating parameters of the voltage measurement channels by applying correction factors derived from calibration measurements. These parameter changes compensate for variations in sampling capacitor values and conversion factors, maintaining measurement precision while keeping the implementation straightforward using standard components and procedures.
Data Source
AI summary
A first step of a calibration procedure is be performed to obtain a first set of voltage measurements by causing each mode switch of a first set of mode switches of a voltage management subsystem to be placed in a first position and each mode switch of a second set of mode switches of the voltage management subsystem to be placed in a second position. Each mode switch is included within a channel of the voltage management subsystem. A second step of the calibration procedure is performed to obtain a second set of voltage measurements by causing each mode switch of the first set of mode switches to be placed in the second position and each mode switch of the second set of mode switches to be placed in the first position.