Engineering topics

Frasch, W.

Publications and source records attributed to Frasch, W..

9 records

NASA NTRS1984

Ultrasonic Bonding of Solar-Cell Leads

Rolling ultrasonic spot-bonding method successfully joins aluminum interconnect fingers to silicon solar cells with copper metalization. Technique combines best features of ultrasonic rotary seam welding and ultrasonic spot bonding: allows fast bond cycles and high indexing speeds without use of solder or flux. Achieves reliable bonds at production rates without damage to solar cells. Bonding system of interest for all solar-cell assemblies and other assemblies using flat leads (rather than round wires).

Frasch, W.↗

NASA NTRS1982

Walking-Beam Solar-Cell Conveyor

Microprocessor-controlled walking-beam conveyor moves cells between work stations in automated assembly line. Conveyor has arm at each work station. In unison arms pick up all solar cells and advance them one station; then beam retracks to be in position for next step. Microprocessor sets beam stroke, speed, and position.

Feder, H.↗

NASA NTRS1982

Vacuum Pickup for Solar Cells

Flexible vacuum cups that handle solar cells conform to shape or cell back surfaces. Cups lift vertically, without tilt that might cause stress on interconnections, inaccurate placement, or damage to cells. Vacuum source is venturi valve mounted on air manifold.

Frasch, W.↗

NASA NTRS1982

Orienting and Applying Flux to Solar Cells

Solar cells are oriented and fluxed automatically at first work station along solar-array assembly line. In under 2 seconds rotary drive rotates cell into proper position for applying solder flux to bus pad on collector side. When contact bus pad is in correct position, capstan drive is disengaged, and vacuum holddown beneath cell is turned on. Flux system lowers and applies preset amount of solder flux to bus pad. Two interconnect tabs are soldered to fluxed areas.

Feder, H.↗

NASA NTRS1982

Work Station For Inverting Solar Cells

Final work station along walking-beam conveyor of solar-array assembly line turns each pretabbed solar cell over, depositing it back-side-up onto landing pad, which centers cell without engaging collector surface. Solar cell arrives at inverting work station collector-side-up with two interconnect tabs attached to collector side. Cells are inverted so that second soldering operation takes place in plain view of operator. Inversion protects collector from damage when handled at later stages of assembly.

Feder, H.↗

NASA NTRS1982

Solar-Cell String Conveyor

String-conveyor portion of solar-array assembly line holds silicon solar cells while assembled into strings and tested. Cells are transported collector-side-down, while uniform cell spacing and registration are maintained. Microprocessor on machine controls indexing of cells.

Frasch, W.↗

NASA NTRS1982

Bonder for Solar-Cell Strings

String bonder for solar-cell arrays eliminates tedious manual assembly procedure that could damage cell face. Vacuum arm picks up face-down cell from cell-inverting work station and transfers it to string conveyor without changing cell orientation. Arm is activated by signal from microprocessor.

Garwood, G.↗

NASA NTRS1982

Transporting Solar-Cell Strings

Vacuum "lance" picks up assembled chain of solar cells from string conveyor without disturbing cells or interconnecting tabs. Lance has 2 vacuum pickups per cell, for total of up to 32 pickups. Positions and number of pickups can be varied. Lance can be adjusted for range of cell sizes, shapes, and spacings.

Bycer, M.↗

NASA NTRS1982

Transfer of Strings to the Module Fixture

Work station for transferring entire strings of solar cells places successive strings alined, with offset, or reversed end for end. Thus, various solar module formats can be accommodated. Two vacuum cups hold each solar cell in string being transferred.

Frasch, W.↗