12 Years experience on PV module testing -testing Services · IEC 61646, Ed. 2 (2008) Thin-film...

1 PV essentials from standards to testing

12 Years experience on PV module testing- testing Services -

TÜV Rheinland Group

C.DreierTÜV Rheinland JapanPhotovoltaicEnergy and Environment TechnologyIndustrial ServicesTel.:+ 81 45 914 [email protected]

W.Vaassen, W.Herrmann, J.Althaus, TÜV Immissionsschutz und Energiesysteme GmbHAm Grauen Stein, 51105 Köln, GermanyTel.:+ 49 221/ 806 2870, Fax + 49 221/806 1350


�Facilities

• TÜV Rheinland, Cologne

• TÜV Rheinland Japan, Yokohama

• TÜV Rheinland Shanghai, Shanghai

• TÜV Rheinland North America, Phoenix

• TÜV Rheinland Taiwan, Taipei


�Type approval qualification of Photovoltaic-ModulesStandards

EN IEC 61215 (1993): Crystalline silicon terrestrial photovoltaic (PV)

modules – Design qualification and type approval

IEC 61215 (2005): Crystalline silicon terrestrial photovoltaic (PV)

modules – Design qualification and type approval

Edition 2

IEC 61646 (2008): Thin-film terrestrial photovoltaic (PV) modules –

Design qualification and type approval

Edition 2

IEC 61730 (2004): Photovoltaic (PV) module safety qualification

- Part 1: Requirements for construction

- Part 2: Requirements for testing


Visual Inspection, Performance, Insulation, Wet leakage

� IEC 61215, Ed. 2 (April 2005) Crystalline silicon terrestrial PV modules - Design qualification and type approval

Preconditioning (5 kWh/m²)

Thermal cycling(200 cycles)

ElectricalParameters

OutdoorTest

Bypass Diode Test

Hot-Spot Test

UV preconditioning


Humidity freezeTest

TerminationsTest

Damp Heat Test

Hail Test

Mech.Load




� IEC 61646, Ed. 2 (2008) Thin-film terrestrial PV modules - Design qualification and type approval


ElectricalParameters

OutdoorTest

Bypass Diode Test

Hot-Spot Test

UV preconditioning


Humidity freezeTest

TerminationsTest

Damp Heat Test

Hail Test

Mech.Load


Light soaking


� IEC 61215Pass Criteria

Extract from IEC 61215:


�Measurement of modulesSteady state solar simulator


�Measurement of modulesFlash type solar simulator (long pulse 800ms) AAA


�Measurement of modulesspectral response equipment


�Measurement of modulesFlash type solar simulator (3m x 3m surface AAA (<1% uniformity))


�Outdoor Test

Outdoor exposure dose:

60 60 kWh/mkWh/m²²NOCT:


�Bypass diode thermal testPossible problem in field installation

3,8°C

37,0°C

10

20

30

Active by-pass diode (closed connection box)

24,7°C

84,1°C

40

60

80

Active by-pass diode (connection box with open lid)


�Bypass diode thermal testExample of test performance

38,0°C

163,0°C

40

60

80

100

120

140

160

Diode type: 80 SQ 045 Tj max = 175°C

CurrentCurrentCurrentCurrent[A][A][A][A]

Box Temperature[[[[°°°°C]C]C]C]

Junction TemperatureJunction TemperatureJunction TemperatureJunction TemperatureTTTTJJJJ [ [ [ [ °°°°C]C]C]C]

4.88 (ISC) 128.2 135.2

6.1 (1.25*ISC) 144.2 151.2


�Hot-Spot endurance testProblem

Cell Voltage

Cell Current

Reverse-Voltage

Module Current

Forward-Voltage

Forward-Voltage

Solar-cellIV-curves

ReducedIrradiationIrradiation

Infraredimages


�Hot-Spot endurance testTest failure

182 °C

326 °C

200

250

300

Hot-Spots can produce severe visible defects on module front and rear side (temperatures > 300 °C !)


�UV-preconditioning testTÜV test chamber Browning effects of EVA

- Dose UV (280 nm - 400 nm): > 15 kWh/m²

- Dose UV-B (280 nm - 320 nm): =3 to 10 % of total UV

- Module temperature: 60 °C


�Climatic-TestsTÜV test facilities


�Climatic-TestsThermal cycling test

200 (50) temperature cycles from -40 °C to 85 °C

Edition 2:

Current flow (IMPP ± 2%) through modules (t > 25 °C)


�Climatic-TestsHumidity-Freeze test


�Climatic-TestsDamp heat test

Test temperature: 85 °C ± 2 °C

Relative Humidity: 85% ± 5%

Test duration: 1000 hours

Module temperature/ °C

Time / h

85

0 500 1000


�Climatic-TestsTest failures I: Module delaminations


�Climatic-TestsTest failures II: Boxes and connectors

Crumbled junction box

Broken and shrunken plugs

Crumbled junction box

Zinc dust


�Climatic-TestsTest failures III: Solar cells

Corrosion of cell interconnector

Cracking of cells

Shifting ofcells

Cell delamination


�Climatic-TestsTest failures IV: Other

Browning of string-connector

Shrinking of foil

Come off of the foil

Glass-corrosion


�Climatic testsTest failure – IV-curves

Reduction of Fill-Factor due to increasement of series resistance

Power loss of strings due to interrupted interconnects


�Climatic testsDamp Heat test, test experience last 5 years


�Mechanical load testTest performance

3 load-tension cycles:

2400 Pa, 1 hour

Optional: 5400 Pa


�Mechanical load testTest failures


�Hail impact testTest performance

Hail impact shots on 10 different locations:

Iceball speed: 23 m/s

Iceball diameter: 2.5 cm


�Light soakingTÜV test facilities


�Summary Test statistic

Measurement of different PV- module typestest results (last 8 years)

0 20 40 60 80 100

%

All Tests

Passed

Fault


�Summary Test statistic of new certification processes

Failure, Module typenot accepted

Certificationwithout anyproblems

Certification with problems(Repeat of tests)

30 %20 %

50 %


� Test failuresHow to continue?

• If the test samples fail in several different qualification tests (i. g. damp-heat, thermal-cycling and hot-spot) we have to reject the complete module design!

The manufacturer can then reapply with an improved design.

• If one qualification test is failed, the following procedure applies:

• The failed test sample(s) will be shipped back to the manufacturer for investigation.

• The manufacturer provides us with a detailed failure analysis report:

• What exactly was the reason for the failure?

• What measures will be taken to avoid such failures?

• With this evaluation report at hand, TÜV decides what tests have to be repeated with new test samples.

• If the repetition of the selected tests is passed, TÜV will issue the certificate.

If the test-repetition is failed again, the module design has to be rejected!


�SummaryConclusion

• Although PV-modules have reached a sophisticated level of technology, a lot of different test-failures occur in laboratory testing

• Manufacturing a PV-Module that is able to pass all qualification tests is a difficult task. All materials, components and process parameters

have to be chosen carefully.

• Even small design changes can effect the suitability of the module design and therefore may require a retesting program to maintain type

approval certification.


Thank you for your kind attention

If you have additional questions:Christian Dreier,

TÜV Rheinland JapanPhotovoltaicEnergy and Environment TechnologyIndustrial ServicesTel.:+ 81 45 914 3888

[email protected]

12 Years experience on PV module testing -testing Services · IEC 61646, Ed. 2 (2008) Thin-film...

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