a pid model: ensuring 25 years of service life1 a pid model - ensuring 25 years service life | pvmrw...

A PID model - ensuring 25 years service life | PVMRW 2015 | M.B. Koentopp et al. | R&D | Golden, CO 24.02.2015 1

A PID model ensuring 25 years of service life

PVMRW 2015, Feb 24th, 2015, Golden, Colorado Max B. Koentopp, Christian Taubitz, Matthias Schütze, Marcel Kröber


I Introduction II PID-s modeling: How do we ensure a 25 year service life with respect to PID-s ? need to have reproducible tests

need to understand progression of PID-s in the field PID-s model need to derive parameters for tests

need to establish process control in production

III Conclusion and Outlook

CONTENTS


INTRODUCTION PID-s CHARACTERISTICS

0 200 400 600

0

3000

6000

Spannung [mV]Voltage V [mV]

solar-cell characteristics

ohmic characteristics

degradation

electroluminescence image

Curr

ent I

[mA]

PID-s Potential induced degradation by shunting of solar cell

Schütze et al., 37th IEEE PVSC, 2011


How do we ensure a 25 year service life with respect to PID-s ? need to have reproducible tests



PID-s MODELING FOR 25 YEARS SERVICE LIFE


LABORATORY PID TEST METHODS

reproducible, but continuous PID stress

Al foil test

HV A

Al foil

climate chamber test (DH)

temperature: 60 °C voltage: -1 kV contacting: indirect via humidity

temperature: 25 °C voltage: -1 kV contacting: Al-foil


common PID-tests represent only one part of PID-s kinetics in the field

Mod

ule-

perf

orm

ance

PROGRESSION OF PID-s LABORATORY ENVIRONMENT VS FIELD CONDITIONS

Laboratory PID-stress

PID

-str

ess

time

Field PID-stress


MODELLING PID-s

Environmental data


MODELLING PID-s

Measured

irradiation ambient temperature relative humidity rain data

module temperature humidity at module surface

Computed

Environmental data


MODELLING PID-s

Environmental data

Rsh-kinetics from lab

measurements


Measurement of shunt resistance (Rsh)

MODELLING PID-s


MODELLING PID-s

shunting (S)-, transition (T)- and regeneration (R)-phase

Taubitz et al., 27th EU PVSEC, 2012

Rsh-kinetics


MODELLING PID-s

Environmental data


measurements

Classification


MODELLING PID-s

bias voltage on? (IRmod > 0 ?)

RHmod > 85 % ? OR

rain ?

S-phase T-phase

yes

yes

no

no

conditions for T-phase

fulfilled?

R-phase

yes

no

Classification


MODELLING PID-s

Environmental data

Rsh simulation


measurements

Classification


MODELLING PID-s Rsh simulation


MODELLING PID-s

ln(b

R) [h

]

6

5

4

3

2

3.103.053.002.952.902.852.80x10-3

1000/TPIS [1/K]

Rsh simulation


Measurement of shunt resistance (Rsh)

COMPARISON TO OUTDOOR MEASUREMENTS



STC power decrease

; resistant samples ; prone samples (type A) ; prone samples (type A) prone sample (type B)

calculation h

calculation min

— — — — --- --- --- ---



STC power decrease


calculation h

calculation min

— — — — --- --- --- ---



good qualitative agreement


calculation h

calculation min

— — — — --- --- --- ---

STC power decrease



Results for full size modules: “Valletta” test site (Thalheim, Germany) test setup

positive grounded

prone modules



1

10

100

1000

0 500 1000 1500 2000 2500 3000 3500 4000

-100

-80

-60

-40

-20

0

20

40

60

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26

Rsh

[kΩ

cm2 ]

time [h]

— calculation h — calculation h, meas. temp. — calculation min — calculation min, meas. temp.

time [week]

— PID prone module string — reference module string

Ys [k

Wh/

kWp]

re

l. de

v. [%

]

STC power decrease

CALCULATION

FIELD MEASUREMENT (Valletta)


How do we ensure a 25 year service life with respect to PID-s ? Need to have reproducible tests

Need to understand progression of PID-s in the field PID-s model Need to derive parameters for tests

Need to establish process control



LONG TERM PREDICTION POSSIBLE

parameters necessary for 25 years service life can be derived

resistant cell-type

prone cell-type

Thalheim, Germany weather data of 2012 used

1.00

10.00

100.00

1000.00

0 100 200 300

Rsh

[kΩ

cm2 ]

time [days]

STC power decrease


PROCESS CONTROL: PRODUCTION MONITORING

module level monitoring (Al-foil test, 168h) weekly sampling: random cells from production are tested on module level monthly sampling: random modules from every conversion site cell level testing (PID cell tester, 24h) weekly sampling: PID-test on cell level (feedback < 48h) fast reaction possible


PROCESS CONTROL: MONITORING DATA CELL PRODUCTION

new test on cell-level


How do we ensure a 25 year service life with respect to PID-s ? Need to have reproducible tests

Need to understand progression of PID-s in the field PID-s model Need to derive parameters for tests

Need to establish process control



I Introduction II PID-s modeling: How do we ensure a 25 year service life with respect to PID-s ? need to have reproducible tests



III Conclusion and Outlook

CONTENTS


CONCLUSION reproducible PID tests are available (Al-foil, climate chamber) laboratory PID-tests represent only part of PID-s kinetics in field studying regeneration properties is essential PID-s model based on laboratory tests and meteorological data can describe long term progression allows for prediction of time of PID-s onset in specific location good qualitative agreement with outdoor measurements continuous production monitoring is essential


OUTLOOK new PID test sites in different climates planned

improvement of model calculations: detailed investigation of interplay between meteorological conditions and PID-s


OUTLOOK

-500

500

1500

2500

3500

4500

5500

0

10

20

30

40

50

60

70

0 100 200 300 400 500 600 700 800 900 1000

21.04.2014, 5 am – 9 pm

new PID test sites in Malaysia and USA planed

improvement of model calculations: detailed investigation of interplay between meteorological conditions and PID-s revision of model equations

temp. measured — temp. calculation (old) — ambient temp. temp. calculation (new) — radiation

radi

atio

n [W

/m2 ]

time [min]

tem

pera

ture

[°C]


Thank you

Golden, 24.02.2015 Max B. Koentopp, Christian Taubitz, Matthias Schütze, Marcel Kröber


ACKNOWLEDGEMENT

This work was partly supported within the Spitzencluster Solarvalley project xμ-Clip (FKZ 03SF0452) by the German Federal Ministry of Research and Technology.

Thanks to co-authors: Christian Taubitz Matthias Schütze Marcel Kröber


PROCESS CONTROL: MONITORING DATA MODULE PRODUCTION

calendar week / Year 2012

Pow

er L

oss

[%]




Pow

er L

oss

[%]

-7-5-3-11

33 44 47 48 61 83 75 77 102 108 106

Mono

-7-5-3-11

119 122 128 136 134 137 147 146 150 152 155 156


Pow

er L

oss

[%]

Mono

-7-5-3-11

167

164

172

171

175

182

180

188

207

198

201

202

203

217

212

221

224

225

227

230Po

wer

Los

s [%

]


Mono

-7-5-3-11

36 34 54 67 57 59 68 71 64 80 65 72 82 74 76 88 78 93 90 98 95 85 87 97 104 99 107

110

113

115

♦ Multi

-7-5-3-11

112

117

118

120

121

126

123

124

125

129

127

130

133

131

132

135

140

141

138

143

142

144

145

148

149

153

151

154

159

160

158

156

157

161Po

wer

Los

s [%

]

♦ Multi

-7-5-3-11

165

163

168

170

177

192

176

195

183

193

187

190

197

199

205

204

208

215

213

219

222

228Po

wer

Los

s [%

]

♦ Multi


ENCAPSULANT INFLUENCE ON PID-s R

sh [Ω

cm2 ]

time after PID-s start [h]

- sheet A - sheet B - sheet C

- sheet A - sheet B - sheet C

Rsh

[Ωcm

2 ]

time after PID-s stop [h]

Decrease in shunting can also lead to a decrease in regeneration

Investigation of degradation and regeneration behavior


INFLUENCE ON PROGRESSION

Simulation of Rsh-kinetics during shunting and regeneration at 49°C

Sheet A: fast shunting + fast regeneration Sheet B: decreased shunting + decreased regeneration


Model-calculations of Rsh-kinetics using weather data measured for Thalheim 2012 .

INFLUENCE ON LONG TERM PROGRESSION

sheet A: fast shunting + fast regeneration sheet B: decreased shunting + decreased regeneration

A module performing better in PID testing might actually fail earlier in the field

a pid model: ensuring 25 years of service life1 a pid model - ensuring 25 years service life | pvmrw...

Documents