Power Storage Cell Control Device Voltage Measurement
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Solution Overview
Problem
Existing power storage module technologies face challenges in measuring the voltage of multiple connected power storage cells simultaneously with high accuracy, leading to inaccuracies in state of charge (SOC) and state of health (SOH) determination, particularly in on-vehicle applications where sequential measurement increases error and reduces the ability to understand cell states accurately.
Innovation Solution
A power storage cell control device is designed with multiple first ADCs, first reference voltage portions, a selector, a voltage value acquirer, and a voltage value corrector, allowing for parallel voltage measurement across multiple cells using highly accurate reference voltages from a second ADC, which corrects measurement errors and enables simultaneous high-accuracy voltage measurement without increasing circuit complexity or shipment work steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sequential voltage measurement using a single ADC is used, then device complexity is reduced, but measurement precision and productivity deteriorate due to inability to measure multiple cells simultaneously
Solution Approach 1:
The patent divides the voltage measurement function into multiple independent ADCs, with each ADC dedicated to measuring a specific power storage cell. This segmentation allows simultaneous measurement of multiple cells without requiring complex multiplexing or sequential switching, thereby improving measurement precision while keeping each measurement channel simple and independent.
Solution Approach 2:
The patent introduces a single second ADC that serves a universal function by measuring reference voltages from multiple first reference voltage portions. This second ADC corrects measurement errors for all first ADCs, providing a multi-functional error correction capability that improves overall measurement precision without requiring separate correction mechanisms for each cell.
2Productivity
If multiple first ADCs are provided for parallel measurement, then productivity and measurement precision improve, but device complexity increases
Solution Approach 1:
The measurement system is segmented into multiple independent first ADCs, each handling one cell's voltage measurement. This segmentation enables parallel operation where each ADC works independently on its designated cell, achieving simultaneous measurement of multiple cells and improving productivity without requiring complex coordination or switching between channels.
Solution Approach 2:
The second ADC acts as an intermediary that measures reference voltages from multiple first reference voltage portions and provides correction data to all first ADCs. This intermediary correction mechanism enables the first ADCs to operate in parallel with improved accuracy, as the second ADC mediates the error correction for the entire system without interfering with the parallel measurement process.
3Measurement precision
If reference voltage accuracy is improved for high-precision measurement, then measurement precision improves, but device complexity and manufacturing cost increase
Solution Approach 1:
The system uses itself to correct measurement errors. The second ADC measures the actual reference voltages used by the first ADCs and generates correction data based on these measurements. This self-service approach allows the system to compensate for reference voltage inaccuracies without requiring external calibration equipment or highly precise reference voltage sources, thereby improving measurement precision while avoiding increased circuit complexity.
Solution Approach 2:
The second ADC provides feedback about the actual reference voltage levels to the control device, which then generates correction data. This feedback mechanism allows the system to dynamically adjust for reference voltage variations, improving measurement precision without requiring the reference voltage sources to be inherently highly accurate, thus avoiding the need for complex reference voltage circuits.
Data Source
AI summary
There are provided a plurality of first ADCs that respectively have voltages of a plurality of power storage cells of a power storage module as inputs. There are provided first reference voltage portions that are provided to respectively correspond to the first ADCs and supply reference voltages VRn used as a criterion for a conversion operation. A selector selects any one of the reference voltages VRn and supplies the selected reference voltage to a second ADC. A voltage value corrector corrects a voltage value of the power storage cell obtained by a voltage value acquirer on the basis of correction data obtained by using a digital signal output from the second ADC.