Vernie Everett, Andrew Blakers, Klaus Weber, Evan Franklin Handling, Assembly, and Electrical...

Vernie Everett, Andrew Blakers, Klaus Weber, Evan Franklin

Handling, Assembly, and Electrical Interconnection of 2nd Generation

SLIVER Solar Cells

3D

2D

Silicon wafer • single crystal• 150mm Ø• 1-3mm thick

100mm

Grooves formed through the wafer

Following grooving, wafer processing proceeds:Diffusions, oxidations, depositions, metallisation.

0.04 to 0.1mm pitch

0.1mm

2mm

100mm

Illu

min

atio

nIll

um

ina

tion

~1,000 completed bifacial SLIVER solar cells, each ~ 2 cm2

Cuts

Sliver Solar Cell

Cross-Section

Illumination

Illum

inat

ion

Perfectly bifacial

Metal (n-electrode)

Metal (p-electrode)

Boron diffusion

Phosphorus diffusion

Surface texturing Phosphorus diffusion AR coating

20-50m 1-2mm

A 2nd Generation SLIVER Technology

Reduce Grooving Pitch and SLIVER Thickness• Strong cost driver• Major challenges• Advantage: with 40 micron pitch, 2.5X surface area increase over 100 micron

pitch, at near-zero cost increase.

Reduce SLIVER Cell Fabrication Complexity• 1st Generation SLIVER cell fabrication required 59 steps• 2nd Generation SLIVER cell fabrication requires only 32 steps• Simplify texturing, improve light-trapping and AR-coating

Broaden Process Windows and Improve Yield and Efficiency• Robust processes with broad process windows• Improve yield: essential for simplified handling and assembly• Improve efficiency. Long term, efficiency will be the deciding factor

1. SLIVER cell fabrication

A 2nd Generation SLIVER Technology

A fundamental change in handling philosophy• Abandoned individual, sequential linear processes.• Moved to group handling modular parallel processes.• Improved yield through simplified separation, “bulk” handling, and a simplified

structure.• Improved throughput with modular process line, with input and output buffers.

Modular sub-assemblies• Conventional cell “analogues”• Avoid individual testing and binning

Versatility through modularity• Two main sub-assembly types: “Rafts”, and “Sheets”.• Separation and handling processes are common for both.• Applications are common for both: cost and efficiency are the only differences.• Rafts and Sheets can be the building blocks of all SLIVER applications.

2. SLIVER handling and assembly

A SLIVER Raft

A Flexible SLIVER Raft

Flexible SLIVER Raft Assembly

SLIVER cells

Soldered electrical interconnections

Simplified process• Eliminated stencilling • Eliminated dispensing• Eliminated cleaning and waste• Eliminated machine vision• Eliminated complex automation Robust process• Simplified alignment requirements• “Automatic” solder volume and location and distribution Conventional materials• reliability, durability, warranty

A 2nd Generation SLIVER Technology 3. SLIVER electrical interconnections

Equipment: low-cost, low-tech, industry-standard. Process: robust, modular, buffered. Materials: conventional, low-cost, reliable. Throughput: 500 – 1,000 connections per second.

Advantages:

A 2nd Generation SLIVER Technology 3. SLIVER electrical interconnections (ctd.)

A 2nd Generation SLIVER Technology

A SLIVER module constructed using Raft Sub-module Technology

A 2nd Generation SLIVER Technology

Reduces silicon consumption by a factor of 10 - 20 Reduces wafer starts by a factor of 20 – 40 Reduces cell fabrication steps from 59 to 32 Simplifies cell fabrication equipment requirements Exceeds 20% cell efficiency [world first for thin production

cells] Reduces assembly equipment cost by a factor of 10 Increases assembly line throughput by a factor of 10 Increases rate of electrical connection by factor of 100 Modularises the entire assembly process Establishes an entire assembly process using only conventional

materials

A 2nd Generation SLIVER Technology Conclusion

Reduce present PV costs by two-thirds Rapidly grow market share Play a significant role in ameliorating

climate change

Mature SLIVER Technology can:

Thank You!