Next-generation interdigitated back-contacted silicon heterojunction solar cells and modules by design and process innovations

www.nextbase-project.eu

NextBase Project Horizon 2020 projects: Backing the European PV industry

EU-funded actions from material research to market deployment

Parallel event at the European Photovoltaic Solar Energy Conference

The Square, Brussels, Belgium

13:30-18:30, Thursday 27 September 2018

Kaining Ding, JÜLICH

This project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 727523

NextBase

NextBase | PresentationSlide 2

(TU Delft)

(EPFL)

(CSEM)

(Meyer Burger)

(IMEC)

(FZU)

(CEA)

General Information

NextBase | PresentationSlide 3

European effort to bring IBC-SHJ technology to ahigher TRL by developing cost competitive andhigh efficiency IBC-SHJ technologies

Project acronym: NextBase

Grant agreement number: 727523

Work programme: LCE-07-2016-2017

Starting date: 01.10.2016

End date: 30.09.2019

Budget: 5,7M€

Grant: 3,8M€

Consortium

NextBase | PresentationSlide 4

14 partners from 8 European countries: 4 industry, 9 research, 1 support

Slide 5 NextBase | Presentation

Objectives

� Demonstrate IBC-SHJ solar cells with efficiency > 26.0%.� Production of highest quality wafers with lifetime over resistivity ratio > 2 ms/Ohmcm.� Introduction of transparent front stack and advanced light management for Jsc > 42 mA/cm²� Development of novel contact materials and contact designs for fill factor (FF) > 82% and Voc > 740 mV.

� Demonstrate IBC-SHJ solar modules with efficiency > 22.0%. � Development of 60-cell interconnection and anti-reflection coating (ARC) for cell-to-module (CTM) ratio > 95%.� Implementation of encapsulation with relative power decrease <5% after degradation.

� Develop an industrial prototype PECVD reactor for IBC-SHJ solar cells. � Production of 6-in wafer with lifetime > 2ms with patterned doped layer.� Demonstration of minimum throughput of 10 wafers per hour.

� Develop processes that allow IBC-SHJ solar module cost of <0.35 €/Wp. � Development of high quality n-type wafers by low-cost multi-pulling process.� Development of various cost competitive patterning and interconnection techniques.

Workpackage Structure

NextBase | PresentationSlide 6

(TU Delft)

(EPFL)

(CSEM)

(Meyer Burger)

(IMEC)

(FZU)

(CEA)

Fabrication of high quality wafer

Slide 7 NextBase | Presentation

NC production of highest quality n-type wafers with lifetime over resistivity ratio > 2 ms/Ohmcm.

� Ingot growth by NC, wafering at MB, testing at imec/CEA/CSEM

� High quality achieved after testing of trial ingots at partners site

� Testing of multi-pulling process to reduce ingot fabrication cost

NextBase’s efficiency chart

Slide 8 NextBase | Presentation

Steady progress of cell efficiency for various patterning techniques since NextBase start

� Contact stack design:

NextBase’s efficiency path

Slide 9 NextBase | Presentation

� Nano-crystalline Si doped layers

(low Eact) improve transport for n-

and p- contact stack

� Only for p-contact: wide bandgap

improve transport selectivity p-contact

Project goal: η > 26 % ↔ FF > 83.5 %

[1] P. Procel, et al., Sol. Energ. Mater. Sol. Cells (2018)

� Patterning design:

NextBase’s efficiency path

Slide 10 NextBase | Presentation

� Optimal n- & p-contact stack

� 200 µm c-Si n-type bulk

� Full TCO/metal coverage on n & p

� 60 % p-finger coverage

� Small pitch

[1] P. Procel, et al., Sol. Energ. Mater. Sol. Cells (2018)

Project goal: η > 26 % ↔ FF > 83.5 %

Cell add-on option 1

Slide 11 NextBase | Presentation

Modulated surface texture

Lifetime above 1ms achieved after damage remove etch (DRE)!

Cell add-on option 2

Slide 12 NextBase | Presentation

CSEM/EPFL* imec FZJ HZB TUD0

1

2

3

4

5

6

* extracted from measured R& EQE

Tota

l Loss

es

(mA

/cm

2)

Front side Rear side TOTAL

Stoichiometric µc-SiC:H

Highly transparent andanti-reflective front stack

Simulated results

Tool development

Slide 13 NextBase | Presentation

90.25 cm²

Upscaling to full size M2 wafer ongoing

eta (%) FF (%)Jsc

(mA/cm2)Voc (V)

HJT (149cm2) 23.7% 81.9% 39.5 0.733 IBC (90.25cm2) 23.8% 79.6% 40.6 0.735 IBC (90.25cm2); x2 ARC 24.2% 79.8% 41.3 0.735

Module interconnection

Slide 14 NextBase | Presentation

Hybrid woven fabric interconnection � Upgraded to: 3D Weave interconnection� Liquid encapsulation tests

Smartwire contacting technology

Anti reflective coating

Slide 15 NextBase | Presentation

Cost analysis

Slide 16 NextBase | Presentation

� IBC is competitive with SHJ� Chance for EU PV manufacturing

1GW scenario:

SHJ Module @ 22.5%Cell Eff. : 0.35 €/Wpk

IBC Module @ 24%Cell Eff.: 0.34 €/Wpk

0

10

20

30

40

50

SHJ SHJ-IBC SHJ SHJ-IBC SHJ SHJ-IBC

Co

O (

c€/W

pk)

Wafer Cell Module

35 c€/Wpk

Simulation #1 Simulation #2 Simulation #3

Progress summary

Slide 17 NextBase | GA04 Jülich

� Wafer target (lifetime over resistivity ratio > 2 ms/Ohmcm) reached

� Jsc target (> 42 mA/cm²) reached

� FF above 81 % achieved

� Laser and shadow mask patterning very promising to reduce cost.

� One-cell module and 2 x 2 dummy module demonstrated.

� Industrial prototype PECVD reactor built.

� Higher throughput 156 x156 mm² IBC-SHJ for module to be targeted.

� Calculation show comparable IBC-SHJ cost at cell and module level.

� Device simulation for IBC-SHJ established.