Battery Charge Estimation for Solar-Powered Window Shading
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Solution Overview
Problem
Existing shading or sun protection devices powered by batteries charged from photovoltaic cells face challenges in determining battery charge levels accurately, especially when energy generation is intermittent or reduced, leading to unpredictable charging and discharging, and voltage hysteresis issues with Ni-Mh batteries.
Innovation Solution
A method and device for determining battery charge level by measuring temperature and voltage, using multiple thresholds to account for hysteresis, and integrating this with a control system to provide accurate charge information without complex calculations, including a computer program for implementation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple temperature-dependent charge thresholds are used to improve measurement precision, then charge level determination accuracy is improved, but device complexity increases
Solution Approach 1:
The patent applies parameter changes by establishing multiple charge thresholds that vary with temperature. Instead of using a single fixed voltage threshold, the system adjusts the threshold values based on measured temperature conditions, thereby improving charge level determination accuracy across different environmental conditions without requiring complex calculation algorithms.
2Measurement precision
If complex calculations are used to determine charge level, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex calculation algorithms with temperature-dependent threshold parameters. By pre-establishing multiple voltage thresholds corresponding to different temperature conditions, the system achieves accurate charge level determination through simple comparison operations rather than complex real-time calculations, thus reducing device complexity while maintaining precision.
3Productivity
If charging continues during motor operation to maintain battery level, then productivity is improved, but loss of energy increases due to charge/discharge currents
Solution Approach 1:
The patent implements periodic action by interrupting the charging process during motor operation. The control device pauses battery charging when the motor is active and resumes charging when the motor stops, thereby preventing energy loss from simultaneous charge/discharge currents while still maintaining overall charging efficiency through periodic charge accumulation.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the charging process during periods when the motor is not operating. The system continuously accumulates battery charge during idle periods to ensure the battery is fully charged and ready for the next motor operation, thereby maximizing productivity while minimizing energy loss during actual use periods.
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
Enables simple and accurate determination of battery charge levels, reducing the impact of charge and discharge currents, and ensuring efficient operation of shading devices by maintaining optimal battery state through maintenance charging modes.
Implementation Method 1
the battery being supplied with electrical energy by photovoltaic elements
Implementation Method 2
means for measuring a temperature in a housing including the power supply control device
Implementation Method 3
means for measuring a voltage across the battery terminals
Data Source
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AI summary
The invention relates to a method for determining the charge level of a battery supplying electrical energy to a device for obscuring an opening in a room of a building or to providing solar protection, the battery being supplied with electrical energy by photovoltaic elements. A control device: - measures a temperature in a box including the power supply control device, - checks if the measured temperature is less than or equal to a single predetermined temperature, - determines a plurality of battery charge threshold values based on the check, - measures (E402) a voltage across the battery terminals, - compares (E403, E406, E407, E410, E411, E414, E415, E419) the measured voltage to at least some of the battery charge thresholds and/or discharge thresholds, - determines a battery charge level (E410, E404, E408, E412, E416) based on the comparisons.