Solar Cell Assembly Front-Side Contact Automation

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Solution Overview

Problem

Existing solar cell assemblies for space use face challenges in efficient manufacturing due to the need for manual handling and complex processes, especially with electrical contacts on opposite sides requiring cumbersome interconnection and protection against radiation damage.

Innovation Solution

The solution involves placing electric contact points on the rear portion of the substrate to make both polarities accessible from the front side, allowing for easier contact bonding and testing, and using a cover glass with cut-outs to protect against radiation and mechanical damage, while interconnectors are designed to be completely protected and flexible to accommodate thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If electrical contacts are placed on opposite sides of the solar cell (front and rear), then the cell structure is simple and manufacturing is straightforward, but the assembly process becomes complex requiring manual handling and cumbersome interconnection

Engineering Contradiction:
Improvesolar cell fabricationVSAvoidassembly process
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent moves the second electrical contact from the rear surface to the front surface of the solar cell, changing the spatial dimension of contact placement. This allows both contacts to be accessed from the same side, enabling automated pick-and-place assembly processes and eliminating the need for complex manual interconnection procedures.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If a cover glass is used to protect against radiation damage, then protection against radiation and mechanical damage is improved, but the manufacturing process becomes more complex and handling more difficult

Engineering Contradiction:
Improveprotection against radiationVSAvoidmanufacturing process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The cover glass is bonded to the solar cell in advance during the cell fabrication process, creating a pre-assembled unit with integrated protection. This preliminary bonding eliminates the need for separate cover glass installation steps during assembly, reducing manufacturing complexity and enabling automated handling of complete, protected units.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If interconnectors are designed to be flexible to accommodate thermal expansion, then reliability under thermal stress is improved, but the interconnector design becomes more complex

Engineering Contradiction:
Improvethermal expansion accommodationVSAvoidinterconnector design
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent designs interconnectors with inherent flexibility to accommodate thermal expansion and contraction of solar cells during temperature cycles. The interconnector geometry and material selection allow for controlled deformation, maintaining electrical connection reliability while absorbing thermal stresses without requiring complex active compensation mechanisms.

Inventive Principle:
Principle #37Thermal expansion

4Extent of automation

If both electrical contacts are made accessible from the front side, then automated assembly and testing are simplified, but the solar cell design becomes more complex requiring additional processing steps

Engineering Contradiction:
Improveassembly and testingVSAvoidsolar cell structure
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

Instead of the conventional approach where contacts are on opposite sides, the patent inverts the design by placing both electrical contacts on the front surface. This inversion enables automated pick-and-place assembly machines to access both contacts from a single side, and allows testing equipment to probe both contacts simultaneously, dramatically simplifying automation while the added processing steps are confined to the cell fabrication stage.

Inventive Principle:
Principle #13The other way round (Inversion)

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 simplifies the manufacturing process, reduces handling steps, and provides effective protection against radiation and mechanical damage, enabling faster and more reliable assembly of solar cell arrays with improved reliability and flexibility.

Implementation Method 1

provides effective protection against radiation and mechanical damage

Methodology Applied
Scientific EffectRadiation protection:

Implementation Method 2

solar cell assembly and method of fabrication of solar cell assembly

Methodology Applied
Scientific EffectPhotovoltaic effect: Photovoltaic Effect

Data Source

PatentEP2546889B1Solar cell assembly and method of fabrication of solar cell assembly
Publication Date: 2020.06.17 AIRBUS DEFENCE & SPACE GMBH
  • EP2546889B1 patent drawingFigure 1~2
  • EP2546889B1 patent drawingFigure 3~4
  • EP2546889B1 patent drawingFigure 5~6

AI summary

A solar cell with a semiconductor substrate (4) having a front surface (4') and a rear surface (4"), wherein a first p-n-junction (3) is provided in the substrate (4) close to the front surface (4') thereof, said p-n-junction separating the substrate into a front portion (306) having a first doping and a rear portion (303) having a second doping; wherein a front layer (1') comprising a further p-n-junction (1) is provided on the front surface (4') of the substrate (4), said p-n-junction separating the front layer into a front portion (1') having said first doping and a rear portion having said second doping and wherein said front layer front portion is averted from said substrate front portion (306); wherein at least one first electric contact (9) is provided on the front side (C') of the solar cell and electrically connected to the front portion of said front layer (1'); wherein at least one second electric contact (8) which is provided on the rear side (C") of the solar cell (C) is electrically connected to a contact point (304) provided on the front side (C') of the solar cell (C) is characterized in that said at least one second electric contact (304) is placed on the bottom surface of a groove (305) which opens to the front side (C') of the solar cell (C) and which extends to the rear portion (303) of the substrate (4) and said electrical connection between the second electric contact (8) and the contact point (304) is provided by the rear portion (303) of the substrate (4).