F R A U N H O F E R C E N T E R F O R S I L I C O N P H O T O V O LTA I C S C S P

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PERC SOLAR CELLS: PROCESS AND FAILURE ANALYSIS

Passivated Emitter and

Rear Contact Solar Cells

� PERC solar cells entering mass

production

� Modified cell process: additional

rear side passivation and modified

contacting technology

� Advantages: reduced surface

recombination and improved optical

properties

� PERC PV-modules with increasing

market share

PERC-Specific Cell and Module

Diagnostics at Fraunhofer CSP

� Performance parameters: Electrical

and optical characterization of cells

and modules

� Rear-contact voids: identification,

quantification and characterization

� LID: Investigation of light induced

degradation (mono-Si, mc-Si)

� PID: Rapid potential induced degra-

dation testing of PERC cells and new

module materials

� Surfaces: Quantitative determination

of surface contaminations

1 LED solar simulator: illumination

with variable spectrum allowing

rapid EQE tests.

2 Microscopic analysis of solar cells

(µLBIC).

Fraunhofer Center for

Silicon Photovoltaics CSP

Otto-Eissfeldt-Str. 12

06120 Halle (Saale) | Germany

Contact

Dr. Marko Turek

Phone +49 345 5589-5121

marko.turek@csp.fraunhofer.de

www.csp.fraunhofer.de

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Application 1: Cell Degradation

� Quantification of long-time cell stabi-

lity regarding light and temperature

induced degradation

� Physical and chemical root cause

analysis of degradation effects

� Investigation and quantification of

regeneration processes

� Localization of electrical losses,

e.g. surface vs bulk

� Quantification of yield losses during

module operation

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Application 2: Rear Contacts and Voids

� Identification, classification and

quantification of voids

� Rear contact analysis: morphology,

composition and homogeneity

� Microstructure characterization of

voids, contact geometry, back surface

field

� Quantification of reduced rear side

passivation due to voids

Application 3: Mechanics

� Benchmarking of mechanical strength

including statistical analysis

� Prediction of breakage rates during all

processes

� Root cause analysis of cell breakage

(fractography, microstructural analysis)

� Electroluminescence strength mea-

surements of solar cells and modules

with bending setups

1 Spatially resolved

characterization of solar cell

before and after degradation.

2 Void and void free rear

contacts: collage of light

microscopy and scanning electron

microscopy.

3 LID test setup: LIDScope (left) and Light Soaker. 4 PID tester PIDcon.

initial

1 cm 200 μm

20 μm

degradation

(LID)