16 m. joanny ok

Imp 154 D - INESFREE DISTRIBUTIONbifi PV workshop 2014.05.26 ChambéryJoanny, Maryline

1

Cell interconnection challenges for

bifacial modules

M. Joanny, B. Soria, A. Bettinelli, P. Lefillastre, B. Novel, H. Robin, R.

Monna, Y. Veschetti, G. Razongles, E. Gerritsen and CEA team

- [email protected]

Direction of Technological Research

Solar Technologies Department

Laboratory of PhotoVoltaic Modules


2

1) Module architecture

2) Front performance

3) Bifacial performance

4) Conclusion

Cell interconnection challenges for bifacial modules

� Objective :

� Content :

To find the best cell interconnection architecture

for bifacial module


3




4) Conclusion


3 bus

interconnect ribbon

1.5 mm

4


• Interconnection schemes evaluated

� n-type bifacial cells 156 mm pseudo square (INES PERT technology 20% efficiency)

� encapsulant EVA standard / EVA UV clear

� glass-glass structure 36 cm x 36 cm x 3 mm

4 bus

interconnect ribbon

1.2 mm

3 bus - ½ cell

interconnect ribbon

1.5 mm

2) Front performance3) Bifacial performance4) Conclusion

* interconnection material provided by Meyer Burger (smartwire technology)

smartwire*

wires with PET film

x 36


5

• Interconnection schemes evaluated

3 bus

interconnect ribbon

1.5 mm

4 bus

interconnect ribbon

1.2 mm

wires with PET film

x 36

interconnect ribbon

1.5 mm



smartwire*3 bus - ½ cell

� n-type bifacial cells 156 mm pseudo square (INES PERT technology 20% efficiency)

� encapsulant EVA standard / EVA UV clear

� glass-glass structure 36 cm x 36 cm x 3 mm

* interconnection material provided by Meyer Burger (smartwire technology)


6




4) Conclusion


7

• STC performance



mask

same total transparent area for all architectures

→ Isc (A), FF (%), Pmax (W)

⇒ CTMIsc (%), CTMFF (%), CTMPmax (%)


8

• STC performance

EVA standard



EVA UV clear

→ 4 bus STC CTM Pmax is 1 % better than 3 bus

→ 3 bus - ½ cell and smartwire show better STC performance than standard 3 bus (respectively 3 %

and 6 %)

≈ 3 % better

≈ 6 % better

≈ 4,5 % better

≈ 5 % better

Isc (A)


9

• Front performance

→ CTMFF slopes are comparable for 3 bus and 4 bus interconnection schemes

→ The lowest CTMFF slope is obtained for the smartwire module

→ Smartwire then 3 bus - ½ cell show the best CTMFF especially at high irradiance

≈ 3,5 % better

≈ 5,5 % better

EVA UV clear

EVA standard


FFmodule

FFcell @ 1000 W/m²


≈ 6,5 % better

≈ 4 % better

700 W/m²

1000 W/m²

1200 W/m²


10


White

screen




11


4 modules with encapsulant EVA standard



White

screen

1

2

→ Using a white screen enables to reach 1,5 to 2% more on Isc and Pmax performance


12




4) Conclusion


13

• Module bifaciality in Pmax


95,7 %

86,8 %87,9 % 88,3 %

Bifaciality


Smartwire allows an

optimized design of the

rear side

1

2

→ Bifaciality obtained for the smartwire module is 95,7 %

→ Bifacialities of 86,8 to 88,3 % are obtained with the other interconnection schemes


14

• Bifacial indoor characterisation set up

� aluminium mirrors

� self-monitoring of irradiance with Isc

� mesh filters → T ≈ 25% and 50%

reflective mirror



mesh filter


15

• Bifacial performance



Pmax @ 0% albedo

Pmax @ 23% albedo

Pmax @ 47% albedo

Pmax @ 100% albedo


16




y = 0,95 x (R² = 0,9993)

Linear regression

Pmax

Pmax1000 W/m²

- 1


17


EVA UV clear

EVA standard

y ≈ 0,95 x

y ≈ 0,84 x

Y ≈ 0,78 x

y ≈ 0,80 x


Pmax

Pmax1000 W/m²

- 1

→ The gain obtained on bifacial modules can reach 0.95 x albedo (smartwire), 0.84 x albedo (3

bus - ½ cell), 0.80 x albedo (4 bus) and 0.78 x albedo (3 bus)



18




4) Conclusion


19

• Summary and conclusion



→ Foreseen follow up : upscale to real size module and characterisation

→ The best performance have been obtained for smartwire and ½ cell schemes

→ The smartwire technology appears very attractive due to both module higher performance

and lower cell price (lower quantities of Ag deposited on cell front (/3) and back (/2) sides)

20

Alternative Energies and Atomic Energy Commission

INES RDI | Savoie Technolac – BP332 – 50 avenue du Lac Léman

F-73377 Le Bourget-du-Lac - FRANCE

T. +33 (0)4 79 79 23 17

Email : [email protected]

Public establishment with commercial and industrial character | RCS Paris B 775 685 019

Thanks for your

attention

Technological Research Division

Department of Solar Technologies

Photovoltaïc Modules Division

FREE DISTRIBUTION: This document may be distributed to other third parties as the contractors. It must be distributed unchanged

and in its entirety and include the issuer’s attribution and credit. This corresponds to the type of licence aa aaaaaaa defined by

http://creativecommons.org/licenses/. However, recipients are requested to exercise sound judgement when redistributing the

document.

Acknowledgements to MeyerBurger for providing the smartwire

materials

16 m. joanny ok

Presentations & Public Speaking