Effects of hygrothermal environment on PID acceleration

for crystalline Si photovoltaic modules

SAYURI-PV 2016

○Yasushi Tachibana, Takeshi Toyoda, Toshiharu Minamikawa (IRII) Yukiko Hara, and Atsushi Masuda (AIST)

２０１６／１０／５

Venue：Auditorium in AIST Tsukuba Central Campus

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Supported by NEDO

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・Combined test = PID test after DH test → Experiment on p-type multicrystalline silicon cell → PID was accelerated by DH test

・Accelerated test of PID → Elucidation of the PID mechanism → Establishment of high acceleration test method

Purpose

Today’s Topics

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p-type multicrystalline silicon cell 2 models (cell A, B)

cell A : Strong DH resistance cell B : Weak DH resistance

EVA film

Glass

Back sheet

Lamination

One cell module

PV Samples

Cell EVA

Glass

Back sheet

Room temperature

w/o voltage

application 85℃,

Procedure of Combined Test

5

DH

PID test

-1000V

85℃ less than 2%rh

4h X 5 (20h)

One cell modules

DH test

DH test 3000h

DH test 4000h

1000h

2000h

DH test : 85℃,85%rh

4 modules

4 modules

4 modules

4 modules

4 modules

PID 0h PID 5h PID 10h PID 15h PID 20h

DH 0h

DH 1000h

DH 2000h

DH 3000h

DH 4000h

EL Images (cell A)

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Pmax (cell A)

・After DH test for 4000 h Pmax reduced by about 5%.

・Pmax of all modules decreased by PID tests. ・Reduction in Pmax after PID test was larger for modules subjected to longer DH test prior to PID test.

0

0.2

0.4

0.6

0.8

1

1.2

0 5 10 15 20

Normalized Pmax

Time of PID test(h)

DH0

DH1000

DH2000

DH3000

DH4000

1.000

1.000

0.986

0.984

0.949

0

0.2

0.4

0.6

0.8

1

1.2

0 1000 2000 3000 4000

Normalized Pmax

Time of DH test (h)

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EL images (cell B) PID 0h PID 5h PID 10h PID 15h PID 20h

DH 0h

DH 1000h

DH 2000h

DH 3000h

DH 4000h

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1.000

1.002

0.989

0.434

0.238 0

0.2

0.4

0.6

0.8

1

1.2

0 1000 2000 3000 4000

Normalized Pmax

Time of DH test (h)

Pmax (cell B)

・Reduction in Pmax was about 1% after DH test for 2000 h. ・Pmax was less than half, after DH test longer than 3000 h.

・For modules subjected to DH test shorter than 2000 h, Pmax decreased by PID test. ・Surprisingly, Pmax increased by PID test for modules subjected to DH test longer than 3000 h prior to PID test.

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

0 5 10 15 20Normalized Pmax

Time of PID test(h)

DH0

DH1000

DH2000

DH3000

DH4000

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Rsh (cell B) Internal shunt resistance (Rsh) of modules were estimated from the

slope around the origin of the dark I-V curve.

Rsh of all modules decreased with an increase in PID test time.

→ PID progressed.

Degradation by DH test was recovered.

→ Recovery was larger than degradation ( DH test longer than 3000 h )

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1.0E+00

1.0E+01

1.0E+02

1.0E+03

1.0E+04

1.0E+05

1.0E+06

0 5 10 15 20

Rsh(Ω)

Time of PID test(h)

DH0

DH1000

DH3000

DH4000

I-V (cell B)

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8

Current (A)

Voltage (V)

DH4000h→PID DH0

DH2000

DH4000

DH4000-

PID20

0

2

4

6

8

10

0 0.2 0.4 0.6 0.8

Current (A)

Voltage (V)

DH3000h→PID DH0

DH2000

DH3000

DH3000-

PID20

・Fill factor and series resistance were recovered by PID test.

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・For the two models of p-type multicrystalline silicon cell Combined test = PID test after DH test

【Cell A and B】 → PID progressed by PID test after DH test 【Cell B】 → Two types of degradation was confirmed → New phenomena that Pmax increased by PID test were found

・PID may be easy to occur in the area of hygrothermal environment, such as tropical zone. → It is important to estimate anti-PID modules in the hygrothermal environment.

Conclusions