lamination technology pv panels€¦ · benefits of the sl-process 50 % reduced lamination time...

18.09.2019 Lamination Technology – PV Panels CONFIDENTIAL

Lamination Technology – PV Panels

Presented By:

Sraisth (M.Sc.-Eng.)

Process Engineer

Research & Development (PV Lamination)

Robert Buerkle GmbH


Agenda

Motivation

Lamination Technology

Glass-Backsheet Lamination

Glass-Glass Lamination

Other Technologies

Summary


Motivation for Glass-Backsheet and Glass-Glass


Module Layers

1 Backsheet

2 EVA Foil

3 Strings with cSi Cells

4 EVA Foil

5 Glass Panel 2.8 – 4 mm

1 Top Tempered Glass: 2 - 3 mm

2 e.g. PVB, POE, EVA Foil

3 Strings with cSi Cells

4 e.g. PVB, POE, EVA Foil

5 Bottom Tempered Float Glass

Panel: 2 - 3 mm

Glass-Backsheet

Glass-Glass


Principle of Lamination Process

Pupper chamber = atmospheric pressure

Plower chamber = atmospheric pressure

1) Transfer of the cold module sandwich into the laminator (with Bürkle Laminator on lifted pins)

Steps of Lamination Cycle

Pupper chamber = vacuum with <1 mbar

Plower chamber = vacuum with <1 mbar

2b) Evacuation of modules without pressure, on lifted pins

2a) Evacuation of modules with low pressure, on lowered pins (not for conventional process)

Pupper chamber = vacuum with approx. 20 mbar

Plower chamber = vacuum with <1 mbar


Principle of Lamination Process

Pupper chamber = process pressure

Plower chamber = vacuum

4) Lamination/Curing



5) Transfer of the laminated module sandwich to the subsequent station



3) Transfer of the pre-curing module sandwich to the subsequent station


Glass-Backsheet Lamination By Buerkle


Principle of Short Lamination (SL-Process)

Step 1 (Lamination)

Vacuum Membrane

Lamination

Step 2 (Cooling)

Flat Press

(top + bottom cooling)e.a.sy.-lam 2141-1 SL


process = 7,5 min

Conventional Process

Temperature

process= 15 min

150

1000

SL- Process

Pressure

Temperature

Pressure

SL-Process against Conventional Process

SL- Process Technology

Reduction of evacuation time

Higher operating temperature allows increase of cross linking speed

(10 °C more operating temperature double the cross linking speed).

Higher pressure ( > atmospheric pressure) avoids emerging of gasses

out of the material and thus no formation of bubbles. (possible

<1700mbar


Heating Plates Lifting Pins

Pneumatic controlled lifting pins ensure homogeneous Temperature within module

Module sandwich heated

on pins to prevent warping;

simultaneous evacuation

Cold module sandwich

(lay-up) on infeed conveyor

Lift up of module sandwich

(lay-up) on heating platen

Module sandwich

pressing module on

heating platen


21.000 mm

3.7

00 m

m

Workflow

Lamination

with vacuum

Final Lamination

Cooling Unit LoadingUnloading

(by using of a cooling press)

26.000 mm

6.7

00 m

m

Pre-Lamination

with vacuumCooling Unit

e.a.sy Lam 2141-1SL

e.a.sy Lam 2141-1VV

Unloading Loading

16.000 mm


Glass-Backsheet Process Development


Gel Content Test Results

y = 1.34x + 84.04

70.0

80.0

90.0

100.0

5.50 5.75 6.00 6.25 6.50

Cro

ss-l

inki

ng

(%)

Process Time (min)

175°C

170°C

165°C

160°C

Linear (165°C)

y = 0.7x + 87

70.0

80.0

90.0

100.0

5.50 5.75 6.00 6.25 6.50

Ge

l Co

nte

nt

(%)

Process Time (min)

175°C

170°C

165°C

160°C

Linear (165°C)

DSC Test Results Soxhlet Chemical Test Results

Encapsulant EVA (Fast Cure)

Backsheet (PPE based)


Electroluminescence Test

Before

Lamination

After

Lamination


Findings from the GB with EVA trials

The temperature uniformity achieved is <±2°C

Process time achieved: 6-7 minutes

Temperature up to 175°C is feasible to use

Pressure should be more than 1000mbar

Process time

6 min

Temp 165⁰C

159

160

161

162

163

164

06:33 06:43 06:53 07:03

Tem

pe

ratu

re (

°C)

Time (minutes)

Temperature Uniformity Measurement

#1 (°C)

#2 (°C)

#3 (°C)

#4 (°C)

#5 (°C)

#6 (°C)


Benefits of the SL-Process

50 % Reduced lamination time

Reduced evacuation time

Small footprint

Reduction of investment costs

Reduction of Operation cost compare to 2 Step lamination system

• only 1 heating unit and 1 Press used


Glass-Glass Lamination By Buerkle


Problems Associated with GG Lamination

Cell/String shifting Bubbles on the corner and on the edges

• High pressure in membrane press without frames cause edge pinching.

• However, using such supports will lead to longer cycle time and adds up NVA operations.

Reasons:



• Incorrect recipe, improper handling of pressure and temperature.

• Basically the incorrect first step (evacuation) of the lamination can lead to such defects

Reasons:

EVA overflow

BubblesCell breakage


→ Bad edge sealing – cosmetics & quality

→ Induced stress – potential reduced life time

→ Higher glass breakage rate – especially with thinner glass

“Edge Pinching” due to higher pressure on the edges

Glass

ΔGlass

Encapsulation & Cells

Membrane



Lamination Solutions for Glass-Glass Modules Overview

Vacuum

+

Frame

Vacuum

+

Autoclave

Vacuum

+

Flat Press

Edge

Treatment

Lamination

Tact Time

Symmetrical

Heating

Others

Frame handling

(loading and

unloading) and

cleaning

Disruption of

inline processing

Small Scale

Production

Proven Mass

Production

Technology by

Bürkle


The e.a.sy-Lam VFF Process Technology for Glass-Glass

Modules

Step 1 (Pre-lamination)

Vacuum Membrane

Lamination

Step 2 (Final lamination)

Flat Press

(top + bottom heating)

Step 3 (Cooling)

Flat Press

(top + bottom cooling)

123


Glass-Glass Process Development


DSC Measurements for Glass-Glass for Different POE

Materials

70%

75%

80%

85%

90%

95%

155°C 160°C 165°C

Cro

ss

-lin

kin

g i

n %

Temperature in Hot-Press 2

Passing Criteria: Gel

content >80%

Passing Criteria:

recommended Gel

Contnet range:

83%~92%

POE Supplier X

POE Supplier Y


Edge Pinching in Glass-Glass Modules

Flat Press Membrane Press


Edge Thickness Measurement

3.2

3.6

4

4.4

4.8

5.2

0

a

1

b

c

d

2

e

f

g

3

h

i

j

4

k

Edge thickness measurement

Outside

Inside 3cm

Max: 0.389mm

Min: 0.086mm

(0.4mm - 0.6mm,

[Cattaneo G. et al.])


Findings from the GG with POE trials

The temperature uniformity achieved is <±2°C

Process time achieved: 6-7 minutes

Temperature up to 165°C is feasible to use

Pressure should be less than atmospheric

161

162

163

164

165

166

13:22 13:32 13:42 13:52 14:02

Tem

pera

ture

(°C

)

Time (minutes)

Temperature Uniformity Measurement

#1 (°C)

#2 (°C)

#3 (°C)

#4 (°C)

#5 (°C)

#6 (°C)

Process time

6 min

Temp: 165⁰C

in HP2


Latest Test Pictures


Controlled and uniform heating and pressure

Thermal oil heating

Split lamination process

• Cycle time reduction

Flat press avoids “edge pinch” effect

• No support frames around the module.

Glass thicknesses of 1 mm are possible.

Controlled and uniform cooling

• minimize internal stress and bowing of the module.

Advantages of VFF Lamination Process


• Pre-lamination step and final lamination step are controlled

independently

• Glass-backsheet modules can be laminated as well

Advantages of VFF Lamination Process


Multi-Stack Laminators


6-level Ypsolar® for GB Modules


6-level Ypsolar® Capacity

8 minutes of cycle time

Per hour 7.5 cycles

Per day = 22h x 7.5 = 165 cycles

Per cycle 12 modules (6 levels x 2 modules)

Per day = 12 x 176 = 1980 modules

1 module = 300W

Per day = 1980 x 300 = 594000 W = 594kW

Per year = 350 x 594kW = 207,900kW = 208MW


Lab Laminator


References

▪ Sraisth, Master Thesis “Achieving higher quality and lower manufacturing cost of solar modules by

improving the lamination process”. TU berlin, March 2017.

▪ ASTM, 2016. Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked

Ethylene Plastics, ASTM D2765 - 16. [Online] Available at: https://www.astm.org/Standards/D2765.htm.

▪ Cattaneo, G. et al., 2015. Lamination process and encapsulation materials for glass–glass PV module

design. PV-tech, March. pp.1-8.

▪ Chen, B.-M., Peng, C.-Y., Cho, J.-L. & Porter, G.A., 2015. Optimization of solar module encapsulant

lamination by optical constant determination of Ethylene-Vinyl Acetate. International Journal of

Photoenergy, 2015(Article ID 276404, 7 pages, 2015. doi:10.1155/2015/276404).

▪ ITRPV, 2019. International Technology Roadmap for Photovoltaic (ITRPV): Results 2018. (10th Edition)

▪ Fraunhofer ISE, 2016. Photovoltaics Report, updated: 17 November 2016. Freiburg: n.pu.

▪ Li, H.-Y. et al., 2013. The effect of cooling press on the encapsulation properties of crystalline

photovoltaic modules: residual stress and adhesion. Progress in Photovoltaics Research and

Applications, DOI: 10.1002/pip.2409.

▪ Perret-Aebi, L.-E. et al., 2010. Insights on EVA lamination process: Where do the bubbles come from?

Valencia, Spain, 2010. 25th European Photovoltaic Solar EnergyConference.

▪ Robert Bürkle GmbH, 2016. Photovoltaikindustrie. [Online] Available at: http://www.buerkle-

gmbh.de/photovoltaikindustrie.html [Accessed 14 December 2016].


Thank You.

Have a good show!

Questions?


The information contained in this presentation is for background propose only and is subject to amendment, revision

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DISCLAIMER


Robert Bürkle GmbHStuttgarter Str. 123

D-72250 FreudenstadtPhone: +49-74 41-58 0Fax: +49-74 41-58 115

Burkle North America, Inc.11105 Knott Avenue

Cypress, CA 90630Phone: +1714-379-50 90

Fax: +1714-379-50 92

Bürkle Machinery (Shanghai) Co., Ltd.

Building 5 & 6, No. 2715, Ledu Road (W)

Songjiang District Shanghai, 201614 - P.R. China

Phone: +86-21-5785 02 88Fax: +86-21-5785 02 58

lamination technology pv panels€¦ · benefits of the sl-process 50 % reduced lamination time...

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