Fuel Cell Stack Voltage Correction via Channel Segmentation
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Solution Overview
Problem
Existing stack cell voltage measurement systems in vehicles face errors due to the resistance differences between modules and the difficulty in measuring each unit cell voltage accurately, especially when a large number of cells are stacked, leading to inaccurate performance management of battery cells.
Innovation Solution
A system comprising a stack voltage measuring unit, a correction variable calculating unit, and a stack voltage value correcting unit that calculates and applies correction variables based on measured stack voltage values during test drives to correct for deviations, ensuring accurate voltage measurements by averaging and storing deviation values for each interval.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If unit cells are stacked in large numbers (300-400 cells) to form a battery pack, then the battery capacity and power output are improved, but measurement errors occur due to resistance differences between modules and connection points
Solution Approach 1:
The battery pack is divided into multiple channels, with each channel containing a subset of unit cells (e.g., 3-4 cells tied together form one channel). This segmentation allows individual measurement of each channel's voltage, enabling identification and correction of measurement errors at the channel level rather than requiring measurement of every single cell.
Solution Approach 2:
The system measures stack voltage under different operating conditions (different current intervals) and calculates correction variables based on these varying parameters. By changing the measurement conditions and comparing results across different current levels, the system identifies and corrects resistance-related measurement errors.
2Ease of operation
If channels are formed by tying unit cells in groups of 3-4 cells for measurement purposes, then the measurement process becomes feasible, but voltage measurement errors occur at connection points due to contact resistance
Solution Approach 1:
The system continuously monitors stack voltage across multiple channels and uses the measured data to calculate correction variables. These correction variables are fed back into the measurement system to compensate for connection resistance errors, creating a closed-loop feedback mechanism that improves measurement accuracy over time.
Solution Approach 2:
The system performs test drives after manufacturing to measure stack voltage under various conditions before actual operation. During this preliminary phase, correction variables are calculated and stored for future use, allowing the system to pre-compensate for measurement errors before normal operation begins.
3Adaptability or versatility
If multiple modules are used in the stack voltage monitoring device to handle large battery packs, then the monitoring capability is improved, but measurement errors occur due to resistance value differences between modules
Solution Approach 1:
The monitoring system is designed to handle multiple channels and modules with a unified measurement and correction approach. The same measurement methodology and correction variable calculation process is applied universally across all channels, allowing the system to scale to large battery packs while maintaining consistent measurement accuracy through the correction mechanism.
Data Source
AI summary
A system for measuring a stack cell voltage of a fuel cell according to the present invention comprises: a stack voltage measuring unit which measures a stack voltage of a stack cell battery for each channel; a correction variable calculating unit which calculates a correction variable by using the stack voltage value measured by the stack voltage measuring unit; and a stack voltage value correcting unit which corrects the stack voltage measured by the stack voltage measuring unit on driving by using the correction variable.