Electrochromic Device Voltage Ramp Calibration
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Solution Overview
Problem
Existing electrochromic devices face challenges in controlling charging/discharging conditions without external sensors, particularly in varying temperatures and configurations, which can lead to reduced lifespan and increased complexity.
Innovation Solution
A method and device that use only electrical measurements, such as open circuit voltage and charging current, to calibrate and control the charging/discharging process, eliminating the need for temperature and transmittance sensors by intermittently ramping voltage and adjusting based on measured conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a high voltage is applied across the electrochromic device to achieve rapid transmittance change, then the transition time is reduced, but the device may be damaged and its lifetime is significantly reduced
Solution Approach 1:
The patent applies dynamic voltage adjustment by ramping the voltage gradually over time rather than applying a fixed high voltage. The voltage ramp rate is calibrated based on initial measurements of the electrochromic device, allowing the system to adapt the charging profile to the specific device characteristics. This dynamic approach enables faster transitions while preventing damage by avoiding excessive voltage spikes.
Solution Approach 2:
The patent changes the voltage parameter dynamically during the charging process. Instead of using a constant high voltage, the system ramps the voltage from an initial level to a final level over a calibrated time period. The ramp rate and final voltage are adjusted based on initial device measurements, optimizing both speed and reliability by matching the voltage profile to the specific electrochromic device characteristics.
2Adaptability or versatility
If temperature sensors and transmittance sensors are included to optimize charging conditions, then the charging control is improved, but the complexity and cost increase and the risk of component failure increases
Solution Approach 1:
The patent implements a self-calibration system that uses the electrochromic device itself to provide calibration information. By measuring the voltage ramp response and transmittance change of the device under test, the system automatically determines the optimal charging parameters without requiring external temperature or transmittance sensors. The device serves its own calibration purpose, eliminating the need for additional sensing components.
Solution Approach 2:
The patent extracts the calibration information directly from the electrochromic device's electrical and optical response during voltage ramping, rather than relying on separate sensor measurements. By taking out the calibration function from external sensors and embedding it in the device's own response characteristics, the system reduces complexity while maintaining adaptability.
3Measurement precision
If sensors are mounted on or near the active area to measure transmittance and temperature, then the measurement accuracy is improved, but the available active area is reduced and the sensitivity to damage during mounting increases
Solution Approach 1:
The patent replaces mechanical sensor mounting systems with an electrical measurement approach. Instead of physically mounting sensors on the active area, the system uses electrical measurements of voltage and current during the voltage ramping process to infer device characteristics. This substitution eliminates the need for physical sensor installation, preserving the full active area and reducing mounting-related damage risks.
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 allows for effective and efficient control of electrochromic devices across different sizes, ages, and configurations, reducing the risk of damage and complexity while maintaining optimal performance.
Implementation Method 1
Electrochromic devices, able to control their light transmittance... By changing an electric potential between the electrochromic layer and the counter electrode layer, ions or electrons are caused to pass the electrolyte layer and the result is a changing or a discharging of the electrochromic layered structure, resulting in a colouring or bleaching of the electrochromic layer
Implementation Method 2
A measure of an initial open circuit voltage between electrodes of the electrochromic device is obtained
Data Source
AI summary
A method for controlling an electrochromic device comprises obtaining (210) of a target colouring level and a measure of an initial colouring level. A measure of an initial open circuit voltage between electrodes of the electrochromic device is obtained (220). A voltage applied between the electrodes is calibration ramped (230). A calibration charging current is measured (232) during the calibration ramping of the voltage. The calibration ramping of the voltage is interrupted (236), intermittently and temporarily and a calibration open circuit voltage is measured (238). The calibration ramping is stopped (240) when a calibration condition is met. A constant main charging/discharging voltage between the electrodes of the electrochromic device is applied (250). The voltage is selected in dependence of the ramped voltage when stopped. Application of a voltage between the electrodes is removed (270) when target colouring level is reached. An electrochromic device capable of performing such procedure is disclosed.