Battery Capacity Estimation via Lookup Table and Aging Compensation
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Solution Overview
Problem
Existing battery capacity estimation methods, such as the OVC lookup table method, are inaccurate due to voltage fluctuations and inability to account for battery aging, leading to incorrect remaining and full charge capacity estimates.
Innovation Solution
A method that corrects recorded battery capacity estimates by using a lookup table and self-consumable capacity adjustments during charging and discharging processes, employing coulomb counting to calculate offset capacities and account for physical aging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the OVC lookup table method is used to estimate battery capacity, then the estimation process is quick and simple, but the estimation accuracy deteriorates due to voltage fluctuations and battery aging
Solution Approach 1:
The patent divides the capacity estimation process into two distinct phases: a quick lookup phase using the OVC table for immediate estimation, and a correction phase that applies aging compensation and voltage fluctuation adjustments. This segmentation allows the system to maintain both speed and accuracy by combining the advantages of different methods at appropriate stages.
Solution Approach 2:
The patent implements feedback mechanisms where the estimated capacity from the lookup table is continuously refined based on voltage fluctuation detection and aging history. The system monitors voltage changes during charge/discharge cycles and feeds this information back to adjust the capacity estimation, thereby compensating for the inaccuracies introduced by voltage instability and battery degradation.
2Device complexity
If the lookup table method is used, then the estimation process is simple, but it cannot account for battery aging which worsens estimation accuracy over time
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing capacity values in the lookup table for various voltage and state of charge conditions. This pre-computed data structure allows the system to quickly retrieve baseline capacity estimates without performing complex real-time calculations, while still maintaining the ability to refine these estimates through aging compensation algorithms that use historical battery performance data.
3Speed
If voltage-based lookup table estimation is used, then the method responds quickly to capacity queries, but voltage fluctuations cause sudden drops and rises in estimated capacity
Solution Approach 1:
The patent applies beforehand cushioning by implementing damping mechanisms that smooth out sudden capacity estimates caused by voltage fluctuations. The system detects abnormal voltage changes and applies correction factors that cushion the impact of these fluctuations on the final capacity reading, preventing the sharp drops and rises that would otherwise occur with pure voltage-based lookup methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method provides accurate remaining and full charge capacity estimates by adjusting for voltage fluctuations and aging, ensuring precise battery capacity calculations.
Implementation Method 1
counting an electric charge capacity discharged by the battery by a coulomb counting method to obtain a count capacity of discharging
Data Source
AI summary
The invention provides a method for estimating a battery capacity of an electronic device. When a current or an average current of the battery is zero, a reference capacity is inquired from a look-up table based on a voltage of the battery. When a previously remaining capacity is greater than a reference capacity, a deduction process of a self-consumable capacity is performed one or more times for a previously recorded remaining capacity to obtain a new recorded remaining capacity smaller than the reference capacity. When the current of the battery is less than zero, a deduction process of a count capacity of discharging is performed one or more times for the previously recorded remaining capacity until a power of the battery is exhausted to obtain a first offset capacity. The first offset capacity is deducted from a previously recorded full charge capacity to estimate a new full charge capacity.