Summary of the 6th workshop on metallization and interconnection for crystalline silicon solar cells

Summary of the 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells 1876 6102 © 2016 The Authors Published by Elsevier Ltd This is an open access article under the CC[.]

Available online at www.sciencedirect.com ScienceDirect Energy Procedia 98 (2016) – 11 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, 2016 Summary of the 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells Guy Beaucarne*a, Gunnar Schubertb, Loïc Tousc, Jaap Hoornstra b a Dow Corning, Parc Industriel, Zone C, Rue Jules Bordet, 7180 Seneffe, Belgium BW Cooperative State University Ravensburg, Fallenbrunnen 2, 88045 Friedrichshafen, Germany c imec, kapeldreef 75, 3001 Leuven, Belgium Abstract The 6th Metallization Workshop took place in Constance, Germany on and May 2016 At the workshop the latest progress in the understanding and application of metallization and interconnection was presented Screen printed metallization continues to dominate Material and application technologies are constantly further improved, with sub-40 μm fingers with high cell performance and low Ag consumption demonstrated Cu plating technology is further perfected in anticipation of large scale industrial implementation, with improvements on adhesion and long term reliability In interconnection, alternatives to the traditional ribbon soldering technology are proposed Among them, the multi-wires interconnection schemes are shown to have a dramatic impact on metallization design and technology © 2016 The Authors Published by Elsevier Ltd This is an open access article under the CC BY-NC-ND license © 2016 The Authors Published by Elsevier Ltd (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the organizing committee of the Metallization Workshop 2016 Peer-review under responsibility of the organizing committee of the Metallization Workshop 2016 Keywords: Metallization; Silicon solar cells ; Interconnection Introduction The Metallization Workshop series started in 2008 At the time, the EU-funded Integrated Project Crystal Clear was running, which included a sub-project on dissemination of knowledge and integration of the European PV R&D community Recognizing the special technological and scientific importance of solar cell metallization, the project coordinator approved and sponsored an open workshop devoted to the topic The purpose was to offer a forum for * Corresponding author Tel.: +32-64-889-294; fax: +32-64-888-950 E-mail address: guy.beaucarne@dowcorning.com 1876-6102 © 2016 The Authors Published by Elsevier Ltd This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer-review under responsibility of the organizing committee of the Metallization Workshop 2016 doi:10.1016/j.egypro.2016.10.089 Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 experts in solar cell metallization and foster interaction between them Although this was meant as a one-time event, the success of the first event led us, the Metallization Workshop organizers, to organize a second workshop, one and a half year later, without any public funding Other editions followed and were also successful, and by now, the Metallization Workshop series is established and recognized as the prime specialized event in the field, attracting a steady number of experts from R&D institutes, universities and industry and made largely possible by private sponsors The 6th Metallization Workshop was held in Konstanz, Germany on 2-3 May 2016 Compared to previous editions, the scope of the Workshop was expanded to cover both cell metallization and interconnection There were several reasons for this First there is a clear trend towards optimizing cell metallization and interconnection simultaneously in order to reach best performance and lowest cost at module level Moreover, there is a clear interaction between cell metallization and interconnection, and today neither can be designed nor developed independently Although the topic of interconnection had been touched upon in several talks at the previous workshops, it was explicitly included in the 6th Workshop to give it the right attention and time The Workshop’s full name has accordingly been modified to ‘Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells’, while the short name remains ‘Metallization Workshop’ The Workshop was this time again a success Around 145 experts, from 21 different countries around the world, attended, and the program consisted of 31 selected presentations The slides and posters are freely accessible at the Workshop website: www.metallizationworkshop.info This paper attempts to give an overview of the Workshop and at the same time to provide a snapshot of the present status and understanding of the science and technology of solar cell metallization and interconnection Screen printed metallization Screen printed metallization (Ag for front contacts, Al for most of the rear surface, and Ag or AgAl for the solderable contacts at the rear) is by far the most dominant technology for crystalline Si solar cells and receives accordingly a lot of attention 2.1 Formation of Ag screen printed contacts The general morphology of screenprinted contacts, featuring Ag crystallites and/or Ag nanocolloids in intimate contact with the silicon surface and an intermediate glass layer has been revealed by many studies in the past ([1-3] and many others) but the formation mechanism is not so well understood At the Workshop, it was proposed that the reactions occurring during Ag contact firing are electrochemical in nature, where the molten glass acts as a liquid electrolyte containing mobile Ag+ and O2- ions [4] Experimental evidence for this mechanism was given, involving electroluminescence imaging, contact resistance measurements and direct measurement of the potential difference between contact and silicon during firing 2.2 Improvement of Ag screen printing pastes Over the last twenty years or so, there has been a constant improvement of Ag screen printing pastes Structures that were deemed impossible at one time, such as contacting a homogeneous emitter with sheet resistance exceeding 60 ohm/sq., not only became possible but also routinely practiced in the industry This was achieved through constant R&D and fast commercialization efforts by paste manufacturers Their astonishing and repeated breakthroughs have been a large contributor to solar cells constant efficiency increase over the years At the Workshop it was shown that these efforts are continuing, with emphasis on understanding and lowering recombination losses underneath Ag contacts [5, 6] and achieving narrow and tall contacts with paste formulation that enable an industrially feasible process [7] Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 A useful technique to help understand the impact of recombination under fingers was introduced, namely the Suns-Photoluminescence, which enables to distinguish between recombination and resistive losses [8] 2.3 Improvement of traditional Ag printing technology It is however not only progress in paste technology that is driving efficiency up and cost down Better and cleverer application of those pastes is also playing a role Two 2-steps technologies enabling thinner fingers and higher aspect ratios than traditional single screen printing have been introduced in the industry over the last few years: dual printing, which involves using a meshed screen to print the busbars and a stencil for the finger print [9] and fine-line double printing (two fine-line prints on top of each other [10]) or FLDP The market adoption of FLDP has been significant over the last few years, whereas the use of stencils has remained limited At the Workshop a further improvement on FLDP was presented It involves decoupling busbars printing from fingers printing The whole front side printing sequence now consists of three consecutive prints, one for the busbars, a first print for fingers and then a second print for fingers on top using the same screen This sophisticated process sequence enables to reduce paste consumption (through reduced paste consumption by applying thin busbars) while achieving narrower linewidths (down to 33 μm) and improved morphology [11] Stencil printing technology is also being improved A stencil-based process was presented featuring a special two layers metal foil stencil, enabling the same high performance as dual printing with only one print instead of two [12, 13] The achievable linewidths, aspect ratios and print variability, along with production data for fill factors and efficiencies, are used by manufacturers as input for detailed modelling to determine the optimal finger pattern and busbar design, taking into account average cell performance and total Ag cost [14, 15] 2.4 Screen printed front contacts for n-type solar cells With the emergence of solar cell technologies where n-type wafers are used instead of the traditional p-type wafers, a new challenge arises to obtain good front contacts That is because such cells use B-doped emitters instead of the usual P-doped emitters for p-type wafers, and it is more difficult to create a good contact by screen printing on such emitters Therefore, contact formation on B-doped surfaces has been an important topic at the previous Workshops, and it was true this time again Particular interest goes into the use of Al in the Ag paste It was shown in the past that introducing a small amount of Al in the Ag paste is effective in reducing contact resistance [16] However, formation of Al-spikes, as a result of an alloying process between the Al and the Si, which are deeper than the junction depth, has been suspected of limiting cell performance A study was presented at the Workshop which studied this aspect with a ‘floating contact’ approach indicated that those spikes not induce significant shunting of p-n junction and carrier recombination [17, 18] However, new generation pastes that have been designed to contact shallow P-doped emitters were shown to lead to better contacts and higher performance than previous generation (Al-containing) Ag front side pastes even on high sheet resistance B-doped emitters [19, 20] 2.5 Screen printed contacts for silicon heterojunction solar cells Another topic at the Workshop relating to an emerging solar cell type is low temperature screen printed contacts for silicon heterojunction solar cells Heterojunction solar cells can reach extremely high efficiencies but cannot be subjected to temperatures higher than ~ 250 °C, otherwise they degrade [21] As a result, such cells have been manufactured using low temperature Ag pastes, which are more expensive and less performant than high temperature screen printing Ag pastes The contributions at the Workshop dealt with the development of novel low Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 temperature pastes [22, 23], and on the interaction between the low temperature Ag contacts and the transparent conductive oxide that is commonly used on such cells [24] 2.6 Snail tracks While Ag screen printing is generally considered to result in reliable contacts, metallization degradation has been observed in some PV systems One important degradation mode is the so-called ‘snail tracks’, a discoloration of the Ag contacts as a result of local surface corrosion At the Workshop, a comprehensive study of the phenomenon was presented, including analysis of modules exposed outdoors and showing snail tracks, but also samples exposed to accelerated aging in climate chambers The study revealed that there is not just one, but four different mechanisms that can lead to snail tracks formation, each with different chemical causes and reaction products [25, 26] Fig Summary of the detailed study of snail tracks presented at the Workshop, showing the reaction products that are formed depending on the degradation mechanism [25] Reproduced with permission from the authors 2.7 Disruptive printing technologies Although screen printing is still clearly the dominant printing technology, some progress was reported on alternative printing methods Dispensing has been under development for several years and is attractive because it can achieve narrow fingers with very high aspect ratios in a single pass At the Workshop, a multi nozzle print head for 156 mm wafers was presented and shown to achieve high printing speeds and high cell performance [27, 28] Progress was also reported for flexographic printing for front side metallization This very high throughput printing technique is very common in the publishing industry, but the low lay-down per pass has been a barrier for implementation in solar This may change with the adoption of multi-wires interconnection schemes, where low metal lay-down is actually desired At the Workshop, first cell results with flexo-printed front side metallization were presented, as well a multi-wires mini-module with an efficiency of 15.8 %, demonstrating the feasibility of the concept [29, 30] Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 2.8 Rear local contacts Although much of R&D attention is going to front contact metallization, rear side metallization is also very important, especially since industrial manufacturing of PERC solar cells has recently started on a large scale Most of those cells make use of locally Si-Al alloyed contacts, and the parameters impacting the morphology and properties of the local contacts are being investigated in detail At the Workshop, a study on the impact of the firing profile on local contacts was presented It was shown that by selecting the right profile, voids formation in the contact areas can be avoided [31] Ni/Cu plated metallization Using an electrochemical metal deposition process instead of screen printing has long been an attractive alternative to Ag paste screen printing, as it enables higher performance and the use of metals with much lower cost than silver, such as nickel and copper Technology adoption however has been slow because of a few technological issues For a long time, it was a challenge to achieve good adhesion between the plated fingers and the cell At the Workshop, a phenomenon was highlighted that plays an important role in finger (lack of) adhesion: plated Cu can self-anneal at room temperature, transitioning from fine-grained to coarse-grained material (Fig 1) This creates stress and is detrimental for adhesion It was reported that appropriate annealing can avoid this effect and result in good finger adhesion [32] Fig Self-annealing effect of Cu-plated fingers [32], reproduced with permission from the authors Several other aspects of plated metallization have been improved such as the laser ablation process, the exact plating sequence and the metallization pattern [33-36] Similarly to screen printed Ag contacts, a transition from to or busbars is taking place resulting in lower total cost of ownership Specific for plated contact however is that this transition also improves finger adhesion [33, 36] An aspect that has long been regarded as a high risk is the lack of long term stability of solar cells metallized by Cu plating This is because Cu diffuses fast in silicon and can drastically decrease lifetime Several studies by now indicate that the risk can be mitigated by the implementation of an appropriate diffusion barrier At the Workshop Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 evidence was given that plated Ni is an effective diffusion barrier, and degradation rates on tests structures were so low that no significant Cu-related degradation is projected to occur for more than 100 years of cell operation [37] It was also reported that, when sputtering is used for the seed layer instead of electroless Ni, special attention needs to be given to avoiding lifetime degradation [38] A non-technical barrier that was discussed intensively at the Workshop is the legal limitation to implementation of large scale electrochemical processes In China, in particular, a license for a plating manufacturing line is required and that was reported not to be easily granted to PV manufacturers However some initial manufacturing indicates that it may not be a showstopper[39] Interconnection The topic of solar cell interconnection was more important in this Workshop than in previous editions of the Workshop, confirming the trend that had resulted in the modification in the Workshop title 4.1 Interconnection with ribbons The dominant technology for solar cell interconnection is to solder flat Cu ribbons coated with solderable alloys onto the Ag electrodes on the cells Although the process may look simple, the phenomena and material aspects taking place during and after soldering are in fact complex One talk at the Workshop introduced the topic of intermetallic compounds (IMCs) These are metallic phases consisting of several metals, which are formed during soldering A detailed study was presented, involving a metallurgical study of soldered and artificially aged soldered joint structures It was shown that, although thin and uniform IMCs are necessary in soldered joints, some compositions and aging conditions may lead to excessive growth and ultimately to failure [40, 41] A disadvantage of traditional soldered interconnection is the multi-step, sequential process : tabbing stringing cell per cell, lay-up followed by lamination A project was presented that explores the concept of assembling all components in one step and achieving interconnection during one lamination/reflow step Early results showed mini-module passing damp heat and thermal cycling tests [42] For some cell structures, traditional soldered interconnection is inappropriate or ineffective In that case, electrically conductive adhesives (ECAs) may be considered An example is the interconnection of heterojunction solar cells cSi/a-Si:H, which cannot sustain conventional soldering temperatures At the Workshop, a study was presented where heterojunction cells metallized with PVD Al were bonded to ribbons using ECAs It showed that, even with a thin intermediate PVD Ag layer, the PVD Al under the ECAs oxidized and resulted in voids and loss of contact after aging [43, 44] A careful design of the electrode metal stack is therefore needed for the formation of reliable interconnection at low temperatures (both soldering with low temperature solder and ECAs) 4.2 Multi-wires interconnection schemes New interconnection schemes radically depart from the traditional structure and no longer use flat Cu ribbons Recently, interconnection based on arrays of parallel Cu wires have received a lot of attention, the so-called Smartwire [45] or Multibusbars [46] approaches They are attractive because they enable in principle higher efficiency (through lower shading) and lower cost (through the lower Ag consumption for the fingers, which can be very thin) In a presentation at the Workshop it was shown that fairly efficient mini-modules could be made with very little Ag consumption per cell, with Cu-paste based metallization, or even without any metallization [47] Not all schemes lead to reliable modules, but some of these new approaches show encouraging accelerated aging test Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 results at mini-module level To reduce cost, it was shown that there are workable alternatives to the low temperature InSn solder alloy which is often used to connect the wires to the metallized fingers A challenge for technologies such as multi-wires based modules that use busbarless cells is to achieve adequate cell measurements in mass production in spite of the absence of busbars This was shown at the Workshop to be achievable using an array of small contacting probes, one for each finger [48] 4.3 Interconnection with conductive backsheets Another alternative interconnection technology, which is applicable for back-contact cells and has been around for several years, makes use of a patterned Cu foil To connect the cells to the foil, the established method is to apply an ECA An alternative for ECAs are low temperature solder pastes, which typically contain Bi instead of Pb At the Workshop, some tests with a low temperature solder paste made with a semi-automated assembly unit were presented [49, 50] The mini-modules made with this approach could pass 400 thermal cycles and 10 humidity freeze cycles 4.4 Shingled cells interconnection A radically different interconnection technology is the so-called shingled cells interconnection, where narrow cells are placed in a module in such a way that they overlap a little with each other In the overlap region the busbar on the rear side of one cell is connected through a joint material to the busbar on the front side of the next cell This structure enables in principle high efficiency modules because there is no shading losses at busbars or ribbons, and the active area is close to 100 % of the total area At the workshop, it was pointed out that the thermomechanical aspects posed challenges to the joint material, and that a material with low elasticity modulus and a high shear strength was preferred [51, 52] Conclusion The 6th Metallization Workshop highlighted great progress in the field of solar cell metallization and interconnection Screen printing is still by far the dominant technology, and further progress towards thinner fingers with high aspect ratio and low Ag consumption was presented The last remaining barriers to large scale implementation of Ni/Cu plating are being removed through intensive development and larger scale industrial demonstration trials For cell interconnection, the traditional technology of soldering flat Cu ribbons is dominating but alternative technologies are emerging, such as multi-wires technologies, which enable in principle efficiency gains and cost decrease via lower cell metallization costs Acknowledgements We thank ISC Konstanz for the great support in the organization of the Workshop, in particular Michaela Schubert and Radovan Kopecek We are grateful to the presenters and authors for their contributions at the 6th Metallization Workshop, and also the participants for their active involvement, especially those who moderated the debates Our gratitude also goes to the sponsors for making this Workshop again possible Further, we would like to thank all members of the Scientific Committee for their involvement in ensuring a high scientific quality of the Workshop: Pietro Altermatt, Jonas Bartsch, Evert Bende, Guy Beaucarne, Thomas Buck, Aba Ebong, Stefan Glunz, Giso Hahn, Jaap Hoornstra, Jörg Horzel, Jooyoul Huh, Alison Lennon, Richard Russell, Andreas Schneider, Loïc Tous and Gunnar Schubert Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 References [1] Ballif C, Huljic.DM, Willeke G, Hessler-Wyser A, Silver thick-film contacts on highly doped n-type silicon emitters: Structural and electronic properties, Applied Physics Letters, 82 (2003) 1878-1880 [2] G Schubert, F.Huster, P Fath Current transport mechanism in printed Ag thick film contacts to an n type emitter of a crystalline silicon solar cell Proceedings 19th European Photovoltaic Solar Energy Conference, (2004) 813-816 [3] Cheng L K, Liang L, Li Z, Nano-Ag Colloids Assisted Tunneling Mechanism for Current Conduction in Front Contact of Crystalline Si Solar Cells, Proceedings 34th IEEE Photovoltaic Specialists Conference, (2009) 2344-2348 [4] Hee-Soo Kim, Sung-Bin Cho, Joo-Youl Huh, Miki Dovrat, Guy Eytan Electrochemical nature of contact firing reactions for front-side Ag metallization of crystalline Si solar cells, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [5] D Inns, Understanding recombination losses from screen printed silver contacts, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [6] D Inns, Understanding recombination losses from screen printed silver contacts, This issue of Energy Procedia, (2016) [7] V Dua, E.Kook, L Jiang, Yi Zhang, Lixin Song, and G Berube, Organic systems to improve finger line shape and transfer for high performance front side metallizations, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [8] Ankit Khanna, Vinod Shanmugam, Johnson Wong, Shubham Duttagupta, Thomas Mueller, Armin Aberle, Rolf Stangl, Advanced characterisation of recombination at metal contacts in silicon wafer solar cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [9] B Heurtault, Jaap Hoornstra, Stencil print applications and progress for crystalline silicon solar cells, 24th European Photovoltaic Solar Energy Conference, (2009) [10] B.Raabe, F Huster, M McCann, P Fath, High aspect ratio screen printed fingers, 20th European Photovoltaic Solar Energy Conference, (2005) 930-933 [11] M Galiazzo, M Bertazzo, A.Maccarrone, A.Querci O Borsato, E Bortoletto, G.Cellere Fine Line Double Printing for Today and Tomorrow Cell Metallization and Module Interconnection Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [12] H Hannebauer, T.Falcon, J Cunnusamy, T Dullweber, Single print metal stencils for high-efficiency PERC solar cells, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [13] H Hannebauer, T.Falcon, J Cunnusamy, T Dullweber, Single print metal stencils for high-efficiency silicon solar cells, This issue of Energy Procedia, (2016) [14] Y Chen, W Deng, A Ali, P.P Altermatt, P.J Verlinden Shape and homogeneity of front metal fingersࡳ impact on cell efficiency and its distribution in production lines Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [15] Y Chen, Y.Yang, W Deng, A Ali, P.J Verlinden, P.P Altermatt, , Front metal finger inhomogeneity: its influence on optimization and on the cell efficiency distribution in production lines, This issue of Energy Procedia, (2016) [16] S Riegel, F.Mutter, T Lauermann, B Terheiden, G Hahn, Review on screen printed metallization on p-type silicon, Energy Procedia, 21 (2012) 14-23 [17] Takayuki Aoyama, Mari Aoki, Isao Sumita, Yasushi Yoshino, Yoshio Ohshita, Atsushi Ogura, Effect of Aluminum in Metallization Paste on the Electrical Losses in Bifacial N-type Crystalline Silicon Solar Cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [18] Takayuki Aoyama, Mari Aoki, Isao Sumita, Yasushi Yoshino, Yoshio Ohshita, Atsushi Ogura, Effect of aluminum in metallization paste on the electrical losses in bifacial n-type crystalline silicon solar cells, This issue of Energy Procedia, (2016) [19] J Engelhardt, S.Fritz, S Riegel, G Hahn, Metallization Techniques–Contact Formation with Al-free Ag Pastes on p+ Layers Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [20] E Kossen, Contacting high ohmic boron emitters with a screen print paste on n-Pasha, Presentation at 6th 10 Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [21] De Wolf S, Descoeudres A, Holman ZC, Ballif C , High-efficiency silicon heterojunction solar cells: a review., Green, (2012) 7-24 [22] S Körner, A.Waltinger, U Partsch, M Eberstein, High performance silver polymer pastes for SHJ cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [23] S Körner, A.Waltinger, M Eberstein Transparent front side contact pastes for high efficiency SHJ-solar cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [24] Ming-Shiou Lin, Kuang-Yang Kuo, Yong-Han Lin, Yueh-Lin Lee, Liang-Pin Chen, Chi-Chun Li, Investigation of metal contacts via thermal treatment at Interfaces between low temperature Ag pastes and TCO layer for HIT solar cell, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [25] I Duerr, J.Bierbaum, J Metzger, J Richter, D Philipp, H Wirth, Silver grid finger corrosion on snail track affected PV modules ϋ Investigation on degradation products and mechanisms Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [26] Ines Duerr, Joerg Bierbaum, Jens Metzger, Jannik Richter, Daniel Philipp, Silver grid finger corrosion on snail track affected PV modules ϋ investigation on degradation products and mechanisms, This issue of Energy Procedia, (2016) [27] M Pospischil, M Klawitter, M Kuchler, M Jahn, R Efinger, R Schwarz, L Wende, M König, F Clement, D Biro High speed dispensing with novel 6’’ print head, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [28] M Pospischil, M Klawitter, M Kuchler, M Jahn, R Efinger, R Schwarz, L Wende, M König, F Clement, D Biro High speed dispensing with novel 6’’ print head, This issue of Energy Procedia, (2016) [29] A Lorenz, A Senne, S Beyer, Y Yao, P Papet, J Ufheil, H Reinecke, F Clement Flexo-printed busbarless solar cells for multi-wire interconnection, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [30] A Lorenz, C Gredy, A Senne, S Beyer, Y Yao, P Papet, J Ufheil, H Reinecke, F Clement Rotational Printing Technology for the Metallization of Highly Efficient Busbarless Solar Cells, This issue of Energy Procedia, (2016) [31] S Mack, P.Richter, S Werner, F Clement, A Wolf Impact of Firing Temperature Profiles on Local BSF Formation in PERC Solar Cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [32] Ning Song, Pei-Chieh Hsiao, Wei Zhang, Xi Wang, Jack Colwell, Zhongtian Li, Alison Lennon, Post-plating annealing of light-induced plated copper fingers: implications for reliable metallisation, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [33 N.Bay, J.Burschik, A.DeRose, A.Hoffmann, H.Kühnlein, M.Passig, D.Pysch, M.Sieber, K.Vosteen, Y.Shengzhao, P.Verlinden, K.Crouse, B.Lee, A.Letize, Transition to and BB designs for Ni/Cu/Ag plated cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [34] S Y Liu, M S Lin, C M Wei, K C Lai, C C Chuang, C C Li Electrical Properties of Forward Bias Plated Ni-Cu Contacts on N-type PERT Solar Cells Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [35] Y L Lee, S.Y.Liu, M S Lin, K C Lai, C C Chuang, C C Li Forward bias plated nickel-copper-tin contacts for crystalline silicon solar cells, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [36] J Burschik, Y Shengzhao, N Bay, K Crouse, A De Rose, A Hoffmann, H Kühnlein, B Lee, A Letize, M Passig, D Pysch, M Sieber, P Verlinden, K.Vosteen Transition to and BB designs for Ni/Cu/Ag plated cells, This issue of Energy Procedia, (2016) [37] S Kluska , J.Bartsch, A Kraft, L Ni, C Wolf, F Schindler, J Schön, M Glatthaar, S W Glunz, Long-Term Stability Evaluation of Copper Contacts on Cell and Module Level, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [38] Sukhvinder Singh, Barry O'Sullivan, Shruti Jambaldinni, Maarten Debucquoy and Jef Poortmans Investigation of radiation damage of Cu plated IBC cells caused by Sputtering of seed layer Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) Guy Beaucarne et al / Energy Procedia 98 (2016) – 11 [39] Webpage 'RENA receives order for copper plating equipment from “Tier 1” solar maker', 2016, http://www.pvmagazine.com/news/details/beitrag/rena-receives-order-for-copper-plating-equipment-from-tier-1-solarmaker_100024713/#axzz4LAiz3F5A [40] T Geipel, M.Moeller, A Kraft, U Eitner, Comprehensive study of intermetallic compounds in solar cell interconnections and their growth kinetics Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [41] T Geipel, M.Moeller, A Kraft, U Eitner, A comprehensive study of intermetallic compounds in solar cell interconnections and their growth kinetics, This issue of Energy Procedia, (2016) [42] Jonas Buddgård, TorgnyLagerstedtand, Andrew Machirant, Accelerated Lifetime Tests of Solution for Production of Photovoltaic Solar Cells Modules at a Reduced Cost Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [43] T Geipel, J.Kumm, M Moeller, L Kroely, A Kraft, U Eitner, A Wolf, Z Zhang, P Wohlfahrt, Low Temperature Interconnection of PVD Aluminium Metallization Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [44] T Geipel, J.Kumm, M Moeller, L Kroely, A Kraft, U Eitner, A Wolf, Z Zhang, P Wohlfahrt, Lowtemperature interconnection of PVD-aluminium metallization, This issue of Energy Procedia, (2016) [45] A Faes, M Despeisse, J Levrat, J Champliaud, N Badel, M Kiaee, T Söderström, Y Yao, R Grischke, M Gragert, J Ufheil, P Papet, B Strahm, G Cattaneo, J Cattin, Y Baumgartner, A Hessler-Wyser, C Ballif, Smartwire solar cell interconnection technology, 29th European Photovoltaic Solar Energy Conference, (2014) [46] Stefan Braun, Giso Hahn, Robin Nissler, Christoph Pönisch, Dirk Habermann, The multi-busbar design: an overview, Energy Procedia, 43 (2013) 86-92 [47] A Faes, M Despeisse, J Levrat, J Champliaud, A Lachowicz, J Geissbühler, N Badel, H Watanabe, T Söderström, Y Yao, J Ufheil, P Papet, B Strahm, J Hermans, A Tomasi, Y Baumgartner, J Cattin, M Kiaee, A Hessler-Wyser, J Fleischer, P.V Fleischer, A Tsuno, C BallifS, Advanced metallization enabled by smart-wire interconnection for silicone heterojunction cell, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [48] S Dauwe, K Ramspeck, T Horn, S Schenk, A Metz, Precise IV measurement of busbarless solar cells including process control methods for production, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [49] Tobias Meßmer, Fatih Demiralp, Andreas Halm, Low cost semi automated assembly unit for small size back contact modules and low cost interconnection approach Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [50] Tobias Meßmer, Fatih Demiralp, Andreas Halm, Low Cost Semi Automated assembly unit for small size back contact modules and low cost intercennection approach, This issue of Energy Procedia, (2016) [51] G Beaucarne, Materials challenge for shingled cells interconnection Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, (2016) [52] G Beaucarne, Materials challenge for shingled cells interconnection This issue of Energy Procedia, (2016) 11 ... nature of contact firing reactions for front-side Ag metallization of crystalline Si solar cells, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, ... Advanced metallization enabled by smart-wire interconnection for silicone heterojunction cell, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells, ... C Li Forward bias plated nickel-copper-tin contacts for crystalline silicon solar cells, Presentation at 6th Workshop on Metallization and Interconnection for Crystalline Silicon Solar Cells,