Photovoltaic Busbar Trenches for Paste Confinement

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Solution Overview

Problem

The manual fabrication of solar panels is time-consuming and error-prone, leading to high costs and reduced reliability due to the complexity of cascaded cell arrangements and the need for precise alignment and bonding of electrodes, which can result in increased internal resistance and contact resistance issues.

Innovation Solution

The use of a specially designed electrode grid with features such as trenches and alignment pads on the busbars to confine conductive paste and prevent overflow, combined with electroplated copper electrodes for reduced resistance and improved tolerance to micro-cracks, allowing for more efficient cascading and bonding of solar cell strips.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If manual fabrication methods are used for solar panels, then flexibility in assembly is maintained, but production time increases and error rates increase

Engineering Contradiction:

Improveproduction throughputVSAvoidfabrication process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The solar cell fabrication process is segmented into distinct functional zones: active areas for light conversion, busbar regions for electrical connection, and trenches for paste containment. This segmentation allows automated processing while maintaining functional integrity, resolving the contradiction between productivity and process complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Trenches and alignment pads are pre-formed on the busbars before conductive paste application. This preliminary structuring enables automated paste deposition with precise confinement, eliminating manual alignment steps and reducing errors while increasing throughput.

Inventive Principle:

Principle #10Preliminary action

2Reliability

If conductive paste is applied without confinement structures, then application process is simple, but paste overflow occurs increasing contact resistance

Engineering Contradiction:

Improveelectrical connection reliabilityVSAvoidelectrode structure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The busbar structure incorporates local quality variations through trenches and alignment pads at specific locations. These localized features confine paste precisely where needed on the busbar surface, ensuring reliable electrical connections without requiring complex overall electrode designs.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Trenches serve as intermediary structures between the conductive paste and the busbar substrate. They physically confine the paste during assembly, preventing overflow onto adjacent cells and reducing contact resistance, thereby improving connection reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Ease of manufacture

If electrode structures are simplified without trenches, then manufacturing is easier, but paste confinement is poor leading to overflow

Engineering Contradiction:

Improveelectrode fabrication easeVSAvoidpaste alignment precision

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

Trenches and alignment pads are integrated into the electrode fabrication process itself, formed during the same electroplating or screen-printing steps that create the busbars. This preliminary formation of confinement structures does not require separate manufacturing steps, maintaining ease of manufacture while achieving precise paste alignment.

Inventive Principle:

Principle #10Preliminary action

4Reliability

If cascaded cell arrangements are implemented, then internal resistance is reduced, but alignment precision requirements increase

Engineering Contradiction:

Improveelectrical performanceVSAvoidcell alignment precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Alignment pads with trenches provide self-aligning features during cascaded cell assembly. The trenches physically guide paste placement and cell positioning, enabling precise alignment through the paste confinement mechanism itself rather than requiring external alignment tools or complex positioning systems.

Inventive Principle:

Principle #25Self-service

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 reduces internal resistance, increases the throughput of solar panel production, and enhances the reliability and durability of the panels by ensuring proper electrical coupling and mechanical bonding while minimizing paste overflow and contact resistance.

Implementation Method 1

electroplated copper electrodes for reduced resistance and improved tolerance to micro-cracks

Methodology Applied

Scientific EffectElectroplating: Electroplating

Data Source

PatentUS9899546B2Photovoltaic cells with electrodes adapted to house conductive paste

Publication Date: 2018.02.20 TESLA INC

AI summary

One embodiment of the present invention provides an electrode grid positioned at least on a first surface of a photovoltaic structure. The electrode grid can include a number of finger lines and an edge busbar positioned at an edge of the photovoltaic structure. The edge busbar can include one or more paste-alignment structures configured to facilitate confinement of conductive paste used for bonding the edge busbar to an opposite edge busbar of an adjacent photovoltaic structure.