Double Bus Bar Electrochromic IGU Voltage Control
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Solution Overview
Problem
Existing electrochromic devices in insulated glazing units (IGUs) exhibit varied performance characteristics, making it challenging to achieve consistent and efficient control over tint levels, as applying a voltage profile to one IGU does not guarantee a similar tint level in another, and there is a need for quicker switching between tint profiles with reduced energy consumption.
Innovation Solution
The implementation of a double bus bar design in electrochromic devices, where the first and second bus bars are strategically located and configured to optimize voltage distribution across the electrochromic stack, allowing for precise control of tint levels and efficient energy use by varying the bus bar locations and configurations to achieve desired transmission states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a voltage profile is applied to an electrochromic device to achieve a desired tint level, then the tint level can be controlled, but the performance varies between different IGUs making consistent control difficult
Solution Approach 1:
The patent modifies the electrical parameters by introducing a double bus bar configuration with specific resistance values. The first bus bar has a first resistance and the second bus bar has a second resistance, allowing different voltage distributions across the electrochromic device. This parameter change enables consistent tint level control by compensating for variations between different IGUs through optimized electrical resistance distribution.
Solution Approach 2:
The patent applies local quality by creating non-uniform electrical resistance distribution through the double bus bar design. The bus bars are positioned at specific locations (e.g., top and bottom edges or opposite sides) with different resistance values, allowing different regions of the electrochromic device to receive optimized voltage profiles. This local optimization ensures consistent performance across varying IGU characteristics.
2Productivity
If traditional single bus bar configuration is used, then the device structure is simple, but switching between tint profiles is slow and energy consumption is high
Solution Approach 1:
The patent segments the electrical connection system into two separate bus bars instead of using a single bus bar. This segmentation allows independent optimization of voltage distribution paths, enabling faster switching between tint profiles by simultaneously applying voltage through multiple paths. The divided configuration reduces the time constant for voltage application while distributing energy more efficiently across the electrochromic device.
3Manufacturing precision
If bus bar locations are fixed, then manufacturing is simplified, but voltage distribution across the electrochromic stack is suboptimal
Solution Approach 1:
The patent designs the double bus bar configuration to serve multiple functions simultaneously: achieving optimal voltage distribution, accommodating variations in IGU manufacturing, and maintaining ease of assembly. The bus bars are positioned at standard locations (edges or corners) that work across different IGU sizes and configurations, making the solution universally applicable while maintaining manufacturing simplicity through standardized positioning.
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 enables consistent and rapid switching between tint profiles across the electrochromic device, ensuring uniform transmission states while minimizing energy consumption, thereby addressing the inconsistencies in existing technologies.
Implementation Method 1
An electrochromic device can reduce the amount of sunlight entering a room or passenger compartment of a vehicle. Conventionally, an electrochromic device can be at a particular transmission state.
Data Source
AI summary
An apparatus is disclosed. The apparatus can include a first conductive layer, a second conductive layer, and an active stack between the first conductive layer and the second conductive layer. The active stack can include an electrochromic material. The apparatus can further include a first bus bar electrically coupled to the first conductive layer and a second bus bar electrically coupled to the second conductive layer, where the active stack, the first bus bar, and the second bus bar are completely between the first conductive layer and the second conductive layer.