Battery Run Time Estimation Using Load-Condition Voltage
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Solution Overview
Problem
Conventional battery run time estimation methods face inaccuracies due to varying battery loads and higher costs associated with tracking charge, especially when batteries are replaced or not deeply discharged.
Innovation Solution
A method utilizing load-condition voltage, which includes a voltage-measuring circuit, open-circuit voltage lookup table, load-condition voltage lookup table, and low-voltage-alarm lookup table, to estimate remaining battery run time by monitoring voltage and calculating capacity decline rates, providing accurate estimates regardless of dynamic loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional voltage monitoring systems are used, then device complexity is reduced, but measurement precision deteriorates due to varying load conditions
Solution Approach 1:
The system dynamically adjusts the voltage measurement approach by switching between open-circuit voltage measurements (when no load is applied) and load-condition voltage measurements (when load is applied). This dynamic adaptation allows accurate run time estimation under varying load conditions without requiring a completely complex new system architecture.
Solution Approach 2:
The system performs preliminary open-circuit voltage measurements to establish a baseline battery capacity before normal operation. This preliminary action provides reference data that simplifies subsequent run time calculations during loaded operation, reducing the complexity of continuous monitoring.
2Measurement precision
If charge tracking systems are implemented, then measurement precision improves, but device complexity increases due to battery integration requirements
Solution Approach 1:
The invention extracts the essential measurement function (voltage monitoring) from the complex charge tracking system. By taking out only the voltage measurement capability and combining it with load detection, the system achieves accurate run time estimation without requiring integrated battery tracking hardware or complex charge accounting mechanisms.
Solution Approach 2:
The system creates a simplified model of battery behavior by measuring voltage under known load conditions and using this data to calculate run time. This copying approach avoids the need for actual charge tracking while still providing accurate predictions through mathematical modeling based on voltage measurements.
3Device complexity
If open-circuit voltage measurements are used, then device complexity is reduced, but measurement precision deteriorates when load is applied
Solution Approach 1:
The system dynamically determines whether to use open-circuit or load-condition voltage measurements based on the current operational state. When the device is idle or in low-power mode, open-circuit measurements are used. When load is applied, the system switches to load-condition voltage measurements, maintaining accuracy across different operating conditions without increasing overall system complexity.
Solution Approach 2:
The system changes the measurement parameter from open-circuit voltage to load-condition voltage based on the applied load. By adjusting which voltage parameter is measured and used for calculations, the system maintains measurement precision across varying operational conditions while using a relatively simple voltage monitoring approach.
Data Source
AI summary
A method for accurately estimating a run time of a battery utilized by an electronic device. The method comprises determining a starting battery capacity utilizing an open-circuit voltage of the battery, determining a battery capacity decline rate utilizing a load-condition voltage of the battery, and determining a low-voltage-alarm battery capacity during an active operation of the electronic device. The method further comprises utilizing the starting battery capacity, the battery capacity decline rate, and the low-voltage-alarm battery capacity to estimate the run time of the battery which may be determined by dividing the difference of the starting battery capacity and the low-voltage-alarm battery capacity by the battery capacity decline rate. One embodiment utilizes an open-circuit voltage lookup table, a load-condition voltage lookup table, and a low-voltage-alarm lookup table that are configured for use with a certain type of battery.