21 supsi workshop_indoor_para_v3_1

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ACCURATE INDOOR DATA FOR ENERGY RATING

J. Hohl-Ebinger, I. Geisemeyer, B. Müller, C. Reise, A. Schmid

Fraunhofer Institute for Solar Energy Systems ISE

PVPMC Workshop

Supsi Canobbio-Lugano, 31.03.2017

www.ise.fraunhofer.de

© Fraunhofer ISE

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Angle-of-incidence (AOI) effects

Spectral response

Absolute module temperature

Irradiance and temperature coefficients

PV MODULE RATINGS

STC

Nominal power 1

+ = $$$

Realistic

conditions

Standardized testing for energy rating (e.g. IEC 61853)

?

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PV Modules


Angle-of-incidence (AOI) measurement

PV Cells (Lower the uncertainty)

Temperature coefficients

Angle-of-incidence (AOI) measurement -

A Study on front texturization

OUTLINE

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Power Rating Matrix:

mandatory (dark green)

at CalLab PV Modules (light green)

on request (grey)

Characterization of PV Modules Power Rating measurements in accordance to IEC 61853

Temperature in °Ct Irradiance in W/m²

15 25 NOCT 50 75

1100

1000 (incl. TC) STC HTC

900

800 NOCT

700

600

500 LTC

400

300

200 LIC

100

CalLab PV Modules:

IV(T) 15-75°C in 1K

steps

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Power Rating is characterization of modules by …

…determination of the irradiance dependency

…evaluation of the temperature coefficients

…determination of incident angle dependency


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Characterization of PV Modules Angular Response Measurement

Part of standard IEC 61853-2

Test set up to rotate module in fixed steps (~7° increments)

Measurement on one single cell, either with electrical connection or by shading this cell

Measured short circuit current is normalized to relative transmittance 𝜏(𝐴𝑂𝐼), which is the „incidence angle modifier (IAM)“ used e. g. in PVSyst

Measured and normalized angular response of a typical PV module

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Characterization of PV Modules Angular Response Measurement

View from inside of the simulator on the tilted module

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PV Modules


Angle-of-incidence (AOI) measurement

PV Cells (Lower the uncertainty)

Temperature coefficients

Angle-of-incidence (AOI) measurement -

A Study on front texturization

OUTLINE

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Temperature Coefficient Determination on Cells T-Dependent Spectral Response

400 600 800 1000 12000

2

4

6

8

10

12

14

16

18

15 °C

25 °C

50 °C

75 °C

Spectr

al R

espon

se [m

A*m

²/W

]

Wavelength [nm]

200 400 600 800 1000 1200-2

0

2

4

6

8

10

12

14

TC

(SR

) [%

/K]

Wavelength [nm]

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Temperature Coefficient Determination on Cells T-Dependent Spectral Mismatch

0.0 0.2 0.4 0.6 0.8 1.0 1.20

20

40

60

80

Co

un

t

MM [%]

MM Max-Min

*Osterwald et al., Temperature-Dependent Spectral Mismatch Corrections, IEEE JOURNAL OF PHOTOVOLTAICS

MM Change (T 15°C->75°C) Class A Simulator Spectrum

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Temperature Coefficient Determination on Cells MM(T) vs MM(const)

Assumtion: 1% MM Change (T 15°C->75°C)

10 20 30 40 50 60 70 803600

3800

4000

4200

4400

4600

4800

5000

P [m

W]

T [°C]

Pmpp(Ti, MM(const)) [mW] -> -19.6mW/K; 0.413%/K

Pmpp(Ti, MM(T)) [mW] -> -18,96mW/K;0.400%/K

9200

9250

9300

9350

9400

9450

Isc [

mA

]

MM(const) -> 2.1mA/K; 0.023%/K

MM(T) -> 3.7mA/K; 0.040%/K

0 100 200 300 400 500 600 7000

2000

4000

6000

8000

10000

Curr

ent

[mA

]

Voltage [mV]

15°C

25°C

50°C

75°C

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Texturization Study

Angular spectral response

Measurement setup

Uncertainty analysis

Test samples (cells & modules)

Different front surface textures

Energy rating

Cells Modules

*Geisemeyer et al., Angle Dependence of Solar Cells and Modules: The Role of Cell Texturization, DOI: 10.1109/JPHOTOV.2016.2614120

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Measurement of AOI Effects Integral vs. Spectrally Resolved

Why spectrally resolved?

Understand differences

Validate simulation models

Low measurement uncertainty


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Angular Spectral Response (SR) Measurement Setup

Filter monochromator

Two light sources

Lock-in procedure

Fully illuminated sample

Cells Modules

Rotary measurement unit

T-control

Rotating bias light

Separates injection-dep.

One axis of rotation


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Angular Spectral Response (SR) Uncertainty Analysis

Based on measured data

Spectral content

Polarization

Uniformity

Angular response of different cells and modules


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400 600 800 1000 120010

-1

100

101

102

U9

5(S

R/S

R0)

/ %

1%

wavelength / nm

AOI = 30°

400 600 800 10000

25

50

75

100

wavelength / nm

Unce

rtain

ty /

%

AOI = 30°

Change in Angular SR Uncertainty Analysis

AOI = 30°: 95% confidence level typically below 1%

UV: Out-of-band radiation, bandwidth, etc…

Visible/: Position of sample and NIR associated uniformity correction

NIR: Temperature

Cells

Uniformity

Temperature

OOB etc.

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NIR: Temperature

AOI = 60°: Increasing influence of adjustment of rotating frame (AOI adjustm.)

10-1

100

101

102

400 600 800 1000 120010

-1

100

101

AOI = 60°

1%

U9

5(S

R/S

R0)

/ % AOI = 30°

1%

U9

5(S

R/S

R0)

/ %

wavelength / nm

Cells

0

25

50

75

100

Unce

rtain

ty /

%

AOI = 30°

400 600 800 10000

25

50

75

100

AOI = 60°

Unce

rtain

ty /

%

wavelength / nm

Uniformity

Temperature OOB etc.

AOI adjustment

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400 600 800 1000 120010

-1

100

101

102

U9

5(S

R/S

R0)

/ %

1%

wavelength / nm

AOI = 30° Cells





NIR: Temperature


400 600 800 10000

25

50

75

100

wavelength / nm

Unce

rtain

ty /

%

AOI = 30°

Uniformity

Temperature

OOB etc.

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10-1

100

101

102

10-1

100

101

400 600 800 1000 120010

-1

100

101

AOI = 75°

AOI = 60°

1%

U9

5(S

R/S

R0)

/ % AOI = 30°

1%

U9

5(S

R/S

R0)

/ %

U9

5(S

R/S

R0)

/ %

wavelength / nm

1%





NIR: Temperature


AOI = 75°: AOI adjustment dominates

Cells

0

25

50

75

100

Unce

rtain

ty /

%

AOI = 30°

0

25

50

75

100

AOI = 60°

Unce

rtain

ty /

%

400 600 800 10000

25

50

75

100

AOI = 75°

Unce

rtain

ty /

%

wavelength / nm

Uniformity

Temperature OOB etc.

AOI adjustment

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Differences in measurement uncertainty for cells and modules

AOIs > 60°: angle adjustment more critical

UV: low signal due to EVA

10-1

100

101

102

1%

U9

5(S

R/S

R0)

/ %


10-1

100

101

102

1%

U9

5(S

R/S

R0)

/ %

AOI = 30°

10-1

100

101

AOI = 60°

1%

U9

5(S

R/S

R0)

/ %

400 600 800 1000 120010

-1

100

101

AOI = 75°U

95(S

R/S

R0)

/ %

wavelength / nm

1%

400 600 800 1000 120010

-1

100

101

102

U9

5(S

R/S

R0)

/ %

wavelength / nm

10-1

100

101

102

1%

U9

5(S

R/S

R0)

/ %

Cells

400 600 800 1000 120010

-1

100

101

102

wavelength / nm

Modules

AOI / °

15 30 45 60 67.5 75 80 85

1)

2)


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Differences in measurement uncertainty for cells and modules

AOIs > 60°: angle adjustment more critical

UV: low signal due to EVA

Change in JSC:

Monte Carlo simulation

Random walks for correlations w.r.t wavelength

Lowest measurement uncertainty reported for relative measurement


400 600 800 1000 120010

-1

100

101

102

U9

5(S

R/S

R0)

/ %

wavelength / nm

Cells

400 600 800 1000 120010

-1

100

101

102

wavelength / nm

Modules

1)

2)

0 15 30 45 60 75 90

0.4

0.6

0.8

1.0

JS

C/J

SC

,0

AOI / °

0 15 30 45 60 75 900.1

1

10

U95 / %

0.5

AOI / °

15 30 45 60 67.5 75 80 85


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Samples Cells and Modules

Six cells

Small area 5 x 5 cm²

p-type Al-BSF

Contacted via micromanipu-lators with Kelvin probes


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Samples Cells and Modules

Six cells

Small area 5 x 5 cm²

p-type Al-BSF

Contacted via micromanipu-lators with Kelvin probes

Modules

Planar glass

Dummy half cells

Open rear

El. conductive tape

Th. conductive gray pad

Side view

Front view Rear view


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Texture Substrate

PLANAR (chemically polished)

Cz-Si

RANDOM PYRAMIDS (alkaline-textured)

Cz-Si

ISOTEXTURE (acidic-textured)

mc-Si

NIL-HC (nano-imprinted honeycombs) *Volk et al., IEEE JPV 5, 1027-1033, 2015

mc-Si

LW-HC (laser-structured honeycombs) *Volk et al., 28th EUPVSEC, 1024-1028, 2013

mc-Si

NANO (shallow nano-textured) *Kafle et al., Solmat 152, 94-102, 2016

mc-Si

Samples Front Surface Textures


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0.6

0.8

1.0

1.2

400 600 800 1000 1200

0.6

0.8

1.0

1.2

SR

/SR

0S

R/S

R0

wavelength / nm

RANDOM PYRAMIDS

PLANAR

Results Change in Angular SR

AOI / °

15 30 45 60 67.5 75 80 85

MODULES CELLS


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0.6

0.8

1.0

1.2

400 600 800 1000 1200

0.6

0.8

1.0

1.2

0.6

0.8

1.0

1.2

400 600 800 1000 1200

0.6

0.8

1.0

1.2

SR

/SR

0S

R/S

R0

wavelength / nm wavelength / nm

RANDOM PYRAMIDS

PLANAR

Results Change in Angular SR

MODULES CELLS

AOI / °

15 30 45 60 67.5 75 80 85 Module level

More similar characteristics

Effects of texture still observable


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CELLS

MODULES

SIMULATION

Results Change in JSC

Cells

PLANAR: Stronger decrease for AOI > 60°

RP: Distinct near-linear decrease for AOI > 15°

Modules

Differences in the range of 1%

RP: Stronger AOI dependence

0.4

0.6

0.8

1.0

0 20 40 60 80

0.4

0.6

0.8

1.0

0 20 40 60 80

20 30 40 50 60

0.92

0.94

0.96

0.98

1.00

1.02

0 20 40 600.85

0.90

0.95

1.00

1.05

JS

C/J

SC

,0

PLANAR

RANDOM PYRAMIDS

JS

C/J

SC

,0

AOI / °

PLANAR

RANDOM PYRAMIDS

AOI / °

EXPERIMENT


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Energy Rating with Measured Data Change in JSC

Three different climate zones

SolarGIS weather data

10 years

15 min resolution

Separated direct and diffuse (AOI 55°) irradiation

Three module orientations

Three inclination angles

0

1

2

3

4

5

6

Rafah, Egypt

Breisach, Germany

Inclin

atio

n

SOUTH

AO

I lo

ss / %

/a

PLANAR

ISO-TEXTURE

RANDOM PYRAMIDS

EASTO

rient

atio

n

Norwich, UK

0

1

2

3

4

5

6

AO

I lo

ss / %

/a

20° 40° 90° 20° 40° 90°0

1

2

3

4

5

6

AO

I lo

ss / %

/a


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Energy Rating with Measured Data Change in JSC

Typically 2-4 % annual loss due to AOI dependence

Up to 1.5 % difference due to front texture

0

1

2

3

4

5

6

Rafah, Egypt

Breisach, Germany

Inclin

atio

n

SOUTH

AO

I lo

ss / %

/a

PLANAR

ISO-TEXTURE

RANDOM PYRAMIDS

EASTO

rient

atio

n

Norwich, UK

0

1

2

3

4

5

6

AO

I lo

ss / %

/a

20° 40° 90° 20° 40° 90°0

1

2

3

4

5

6

AO

I lo

ss / %

/a


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Energy Rating with Measured Data Cell-to-Module Losses in JSC

Convolution of SR with AM1.5g (before and after encapsulation)

Simulated annual AOI loss (based on measured data)

Cell-to-module:

NIL-HC: -4.0 %

RP: -2.7 %

ISO: -1.1 %

AOI losses:

RP loses initial advantage over ISO almost completely

NIL-HC LW-HC RP ISO PLANAR

32

33

34

35

36

37

38

JS

C / m

A/c

m2

JSC

cell

JSC

module

JSC

module with annual loss AOI

Norwich (UK), Orientation: South, Inclination: 40°

-4.0%

-2.7%

-1.1%

Small area laboratory cells and mini modules!

-2.3%

-2.7%

-2.2%

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Conclusion

Measurement setup for angular SR: Bias light rotating with the sample

400 600 800 1000 120010

-1

100

101

102

U9

5(S

R/S

R0)

/ %

wavelength / nm

0 15 30 45 60 75 90

0.4

0.6

0.8

1.0

JS

C/J

SC

,0

AOI / °

0 15 30 45 60 75 900.1

1

10

U9

5 /

%

0.5

Results for cells and modules: Modules: Differences ≈ 1%

Combination of CTM and AOI losses: Random pyramids lose initial advan-tage over isotexture

Uncertainty analysis: Change in SR: U95(AOI < 75°) < 1% Change in JSC: U95(AOI < 60°) ≈ 0.5%

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Acknowledgment

This work was partly funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (Contract Number 0325447 OHM) and the EMRP ENG55 project “Towards an energy-based parameter for photovoltaic classifi-cation”. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.

Jochen Hohl-Ebinger www.ise.fraunhofer.de [email protected]

Thank You Very Much for Your Attention!

21 supsi workshop_indoor_para_v3_1

Technology