Solar Cell IV Characterization Using High-Intensity Light Pulses
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Solution Overview
Problem
Current methods for measuring the current-voltage characteristics of solar cells and modules are time-consuming, limiting production line throughput due to the slow response time of solar cells when switching between voltage conditions.
Innovation Solution
The technique involves supplementing incident light with short, high-intensity pulses to rapidly ramp up the voltage of solar cells or modules, allowing for faster measurement of steady-state voltage and current characteristics by applying higher intensity light during voltage transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional measurement apparatus is used to measure solar cell characteristics at different voltages, then measurement accuracy is maintained, but measurement time increases significantly
Solution Approach 1:
The patent applies periodic pulsed illumination instead of continuous illumination. A control circuit switches the light source between illuminated and non-illuminated states in periodic cycles, allowing the solar cell to reach steady-state voltage quickly during each pulse while maintaining measurement accuracy through synchronized detection during the illuminated phase.
Solution Approach 2:
The patent uses preliminary action by pre-charging the solar cell with a light pulse before actual measurement. The control circuit illuminates the solar cell for a predetermined time to ensure it reaches steady-state voltage conditions before the measurement phase begins, eliminating the need to wait for voltage ramp-up during each measurement cycle.
2Stability of the object's composition
If continuous illumination is used to maintain steady-state voltage, then voltage stability is achieved, but power consumption increases
Solution Approach 1:
The patent implements periodic illumination where the light source is switched on and off in cycles. During the illuminated phase, the solar cell generates voltage and current for measurement. During the non-illuminated phase, power consumption is eliminated while the cell retains sufficient voltage memory to allow rapid re-establishment of steady-state conditions when illumination resumes.
Solution Approach 2:
The patent maintains continuity of useful action by ensuring that measurements are taken during the illuminated phase when the solar cell is actively generating power. The control circuit synchronizes detection with the illumination cycles, ensuring that no useful measurement opportunity is lost while minimizing total illumination time to reduce power consumption.
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 approach significantly reduces measurement time, enabling faster production throughput and lower power consumption, with total measurement time reduced by a factor of three, while avoiding circuit ringing issues associated with abrupt current changes.
Implementation Method 1
the solar cell (or module) is placed into a short-circuit condition and is illuminated at one sun intensity
Implementation Method 2
a higher intensity light pulse is also applied to the solar cell or module, for example, a light pulse at three suns intensity
Data Source
AI summary
A solar cell or module is illuminated at one sun intensity and is placed into short circuit. Current and voltage measurements are taken. Control circuitry commands a second, higher terminal voltage of the solar cell such as a maximum power voltage. A higher intensity light pulse (for example, three suns) is applied to the solar cell or module when the second voltage is commanded. Voltage ramps more quickly because of the high-intensity light pulse. When the second terminal voltage is reached the light pulse terminates and measurements are taken while the solar cell remains illuminated at one sun intensity. The solar cell is placed into open circuit conditions and in conjunction with that action another high-intensity light pulse is applied. When the steady-state open circuit voltage for one sun is reached the pulse terminates. Characteristics are measured including current and voltage at the terminals of the solar cell or module.