Building Integration of CIGS ThinFilm Solar Modules

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Building Integration of CIGS Thin-Film Solar
Modules

• A Presentation of the FP5 Project HIPERPB
• by Johann Springer
• Zentrum für Sonnenenergie- und Wasserstoff-Forschu
  ng Baden-Württemberg
• (Centre for Solar Energy and Hydrogen Research)
  ZSW
• Hessbruehlstr. 21C
• D 70565 Stuttgart
• Germany
• tel. [phone]
• www.zsw-bw.de
• johann.springer_at_zsw-bw.de

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The Project
HIPERPB High Performance Photovoltaics in
Buildings ERK6-CT1999-00009 01.04.2000 to
30.09.2003
Specific aspects of building integration of the
emerging, auspicious thin-film PV-technology with
Cu(In,Ga)Se2 absorber (CIGS or CIS)
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The Consortium
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Statements and Motivation

• Often PV is added to the buildings
• Often PV is not part of the building
• Often PV disturbs the appearance of the
  building
• PV on Buildings instead of PV in Buildings

• PV should be an integrated part of the building
• more than one function of the PV elements
• PV should beautify the building
• better acceptance, higher value

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And The differences between c-Si modules and
CIGS-thin-film modules need to be considered and
offer advantages
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Objectives of the project
CIGS Module
Façade
Roof
Building
General
Photovoltaics
Hot spots
Design
Safety
Acceptance
Shading
Standards
Fixing
Module design
Costs
Wiring
Monument prot.
Stability
Semi-transparency
Struct. glazing
System comp.
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Project Structure
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Roles of the partners
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State of the art PV in Roofs
Si-modules for roof integration Braas Schweiz
er
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Examples of PV in Buildings
c-Si modules in a rooflight - historic building
in Bern, CH (Atlantis Solarsysteme AG)
Atlantis SUNSLATES TM roof integration of c-Si
modules (Bern, CH)
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CIS-Solar Modules Background

• Thin-Film Solar modules with absorber CIGS
  -Cu(In,Ga)Se2
• Development in several institutions
• Siemens Solar, USA, D
• ZSW and IPE, Stuttgart
• NREL, Denver
• Ångström Solar Center, Uppsala
• Matsushita, Showa-Shell, Japan
• Pilot plants and beginning manufacturing
• Siemens Solar, USA
• Würth Solar, Germany
• ISET, USA
• Global Solar Energy, USA
• EPV, USA
• Japan, ...............

Cell efficiency lt19 Modules lt12
Competitors CdTe, a-Si, c-Si
Actual market share lt 1
Advantages low manufacturing costs due to
materials saving and large area processing
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Structure of a CIGS Thin-Film Solar Module
Front Glass
Encapsulation
Hot melt
PV layers
ZnOAl
i-ZnO
CdS
Zelle n
Zelle n1
CIGS
Mo
Glass
Substrate
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Specific Aspects of CIGS Thin-Film PV for
Building Integration

• Homogeneous Appearance
• Uniform black colour, pinstripe suit design
• Preferred size (e.g. 120 cm x 60cm), but also
  wide range of other formats
• Larger sizes made as patch-work modules
• Glass-(EVA)-glass composite
• Semi-transparency possible
• Shading and hot-spot behaviour different from
  crystalline modules
• Substrate structure allows choice of front
  glass
• Relatively high voltages favour parallel
  interconnection

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Building regulations and PVIB
A very critical issue, some provoking questions

• Main problem
• A lot of national, regional and local building
  regulations
• Nearly no European regulations existing (one
  for structural sealant glazing systems but
  applicable for PV???)
• PV in Buildings architectural glazing?
• Rules for glass products valid for PV modules?
• Question of product definitions
• PV module laminated glass, safety glass ?
• Impact of lamination material (EVA, PVB, ..)
• Any type approval of solar modules for facades ?
• If not, approval for the individual case required
  (ZiE)?
• If not, who assumes liability if anything
  happens?
• Urgent call for action!

PVIB, a legal grey area?
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Fixing Technology (mech.)

• Wall-mounting of facade elements (glass, stone,
  brick, PV, ...)
• Transom-mullion (Pfosten-Riegel) construction
• Bolt-hook systems (Bolzen-Agraffe)
• Structural sealant glazing systems (SSGS)

New WBS (Welded Bond System) Glaswerke Arnold , D

• Principle
• A stainless-steel tape is laminated to the back
  of the glass-glass module (or other laminated
  glass)
• Bolts, screws or other fixing elements are welded
  to the tape
• Can be combined with all standard wall systems
• Developed for glass, well suited for PV

Type approval pending
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Fixing Technology - Use of existing facade
systemsMounting of frameless façade plates /
Ventilated façade
A system with agrafes, suited for WBS
A system with clips
BWM
BWM
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Electrical Interconnection

• Development of a junction box especially suited
  for CIGS-modules
• low-cost
• small-size
• parallel or series interconnection
• bypass diode(s) possible

Lab model
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Hot spots and shading
Objective To avoid damage of CIS-modules in
buildings in the case of partial
shading. Approach Performance tests of
CIS-modules subject to shading Analysis of
IV-curves Prototype fabrication and verification
tests Preliminary result CIS-modules seem to
have good shading tolerance
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IV curves of CIS module (60x120 cm²) subject to
partial shading
shaded (different sets of 3 cells)
unshaded
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RESULTS - Roof
Atlantis SUNSLATETM with CIS-modules
Traditional SUNSLATE with c-Si cells
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CIGS generator at ZSWs solar test field
Not a roof, but gives a visual impression of a
roof with integrated CIGS modules
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Option for PV integration the
Rheinzink-Treppendach Quickstep
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Result CIS Solar Tower in Heilbronn (Würth Solar)
40 kW CIGS modules
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Further Perspectives of CIGS in Buildings

• Large area modules
• Semitransparent modules in warm façades and glass
  roofs
• Integration of thermal insulation, cooling,
  heating, noise barrier (e.g. in railings of
  window façades)
• Solar massive roof with CIS modules
• Combination with load bearing parts (concrete
  panels, ..)
• Combination with solar thermal
• Flexible modules
• 3-D modules
• Tayloring of electrical parameters and
  geometrical shapes
• Combination with solar cooling
• Shading with semitransparent CIGS modules
• Concentration

NEW FP5 PROJECTS??
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CONCLUSION

• CIGS thin-film solar modules are an emerging
  technology
• CIGS modules are very suitable for building
  integration
• Conversion efficiency is about 10
• Standard sizes (120 cm x 60 cm) and special
  smaller sizes available
• Larger sizes with patchwork modules possible
• Use of standard facade elements combined with new
  mounting technology
• Replacement of c-Si in Sunslate roof shingles
• Combination of electrical interconnection and
  mechanical fixing in development