Low-Voltage Battery SOC Correction Using Charge Time and Voltage
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Solution Overview
Problem
Conventional methods for calculating the state of charge (SOC) of low-voltage batteries in electric vehicles inaccurately account for charging efficiency, leading to a growing discrepancy between calculated and real SOC values.
Innovation Solution
An apparatus and method that utilize a table correlating SOC values with charging voltage and time, and a controller to correct the SOC based on this data, reducing the discrepancy by periodically updating the SOC value when the number of charges exceeds a reference threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the SOC is calculated without considering charging efficiency, then the calculation process is simple, but the accuracy of SOC value deteriorates over time
Solution Approach 1:
The patent pre-calculates and stores correction values in a table during the design phase, corresponding to different charging voltages and charging times. During actual operation, the controller only needs to lookup the pre-stored correction value based on measured charging parameters, avoiding complex real-time calculations while maintaining high accuracy.
Solution Approach 2:
The patent introduces a correction value as an intermediary element between the simple IBS calculation and the accurate real SOC. This correction value, stored in a table and derived from charging efficiency considerations, mediates the discrepancy between calculated and actual SOC without requiring complex real-time computation.
2Measurement precision
If the SOC is corrected frequently, then the accuracy of SOC value is improved, but the computational burden increases
Solution Approach 1:
The correction values are pre-calculated and stored in a table during system design, eliminating the need for frequent complex computations. The controller simply retrieves the appropriate correction value from the pre-populated table based on measured charging voltage and time, significantly reducing computational burden while maintaining accuracy.
Solution Approach 2:
The patent implements periodic correction by counting charging events and applying correction only when the count exceeds a reference value. This periodic approach balances accuracy improvement with computational efficiency, avoiding excessive corrections while maintaining SOC accuracy over multiple charging cycles.
Data Source
AI summary
An apparatus for correcting a state of charge (SOC) of a low-voltage battery inside a vehicle and a method for the same are provided. The apparatus includes a storage storing a table having an SOC value corresponding to a charging voltage and a charging time of the low-voltage battery inside the vehicle, a voltage sensor to measure the charging voltage of the low-voltage battery, and a controller to measure the charging time of the low-voltage battery, determine, from the table, the SOC value corresponding to the measured charging time and the measured charging voltage, and correct the SOC value of the low-voltage battery, based on the determined SOC value.