Quality Assurance and Production Optimization for PV Module Production - Killing two Birds with one Stone

Transcription

1 Quality Assurance and Production Optimization for PV Module Production - Killing two Birds with one Stone Dr. Ilka Luck and Dr. Steffen Schuler

2 Outline 1. PICON Solar introduction 2. The quality issue 3. Examples for the costs of not doing quality assurance and quality management 4. How QA and QM automatically results in production optimization 5. Conclusion

3 About PICON Solar PICON Solar worldwide consulting at the crossing point where technology and client s features translate into unique strategy. Services: i. quality assurance, bankability issues ii. production optimization iii. technology and process development iv. strategic business development iv. custom-made studies on technologies and products Typical clients: We have no typical clients! Financial institutions as well as government institutions. Module and component producers, raw material suppliers as well as equipment manufacturers. Technology start-ups as well as multi billion turn-over corporations.

4 About PICON Solar Dr. Ilka Luck 2008 Founding of PICON Solar as managing partner Managing director of Global Solar Energy Deutschland GmbH 2006 Co-founding partner of PI Berlin among other companies in the renewable energy sector, business angel Founder and managing director of Sulfurcell Solartechnik GmbH, today Soltecture Dr. Steffen Schuler since 2011 Principal Consultantwith PICON Solar Head of Technology, Global Solar Energy Deutschland Team Leader Product Engineering for Fab-Cluster Technology Transfer, QimondaAG, Dresden Product Engineer for DRAM Component Yield Enhancement, Infineon Technologies / Qimonda AG, Dresden Post Doctoral Researcher, Hahn-Meitner-Institut Berlin, Dept. of Solar Energy

5 The Quality Issue PV, especially c-si based PV used to be considered a well established technology coming with the corresponding long-term stability. More and more PV plants show a life time of 20 years and beyond. When the German EEG and other subsidies triggered the tremendous demand for PV modules availability was all that mattered. Industrial productions often run by companies that have not yet accumulated long-term experience with PV module reliability superseded the former manufactures. The need for profit, later the enormous cost pressure introduces new materials and processes no long-term experience available and with IEC standards insufficient for life time projections. Failures in the field occur some completely new, some long thought overcome. Investors, financing and insuring institutions have become concerned about the safety of their project profitability. The quality issue is back!

6 Yellowing a failure long thought gone yellowing appeared within months after installation coming with significant power degradation. the use of uncertified material turned out to be the origin of this failure. violation of product warranty! Replacement costs as high as 450 k per MWp. power warranty to be violated within 2 4 years after installation financial loss for PV plant owner per MWp as high as * in year 2 alone that will further accumulate! Degradation will not stop at 90 % of the initial power after 2 years! Consequences Investor: Manufacturer: substantial financial loss loss of reputation, significant additional replacement costs * Assuming 0,45 /Wp, 1000 MWh/MWp, FIT 0,25 ct/kwh

7 How to ensure Module Quality Check before installation (e.g. PI s quality test-packages, PI China s pre-shipment checks, PICON s factory inspections)! Advantages: Disadvantage: you get what you pay for (power at STC) first impression of potential module performance (EL, PID, Peel, Weak Light, sometimes LID and Hot-Spot) probe size often not of statistical relevance long term stability not addressed due to lack of time (long-term climate chamber testing, UV) Better have the module manufacturer check for quality as well! Quality assurance and quality management in PV module production Manufacturers comment: Too expensive! Are you aware of the cost pressure out there? People don t pay for quality. Sadly right in the past years. However, it is changing. But is QA and QM really too expensive? Let s have a look at the costs of not doing QA and QM.

8 Inexact power determination Manufacturer C is perfectly fine*. Satisfying customer expectations and not over delivering. Manufacturer A is losing** almost 50 k due to downgrading of 1 % production volume and almost 140 k by not upgrading 3 % of production volume. Manufacturer B underperforms. He loses** 1.6 Mio due to downgrading and weakening his reputation. Manufacturer D is clearly not in control of his process which does not help his reputation. He loses 936 k due to downgrading and almost 1.3 Mio by not upgrading. within error margin of measurement Counteraction: Continuous referencing and calibration of sun simulator. * assuming a -0% / +5% sorting ** assuming 500 MWp annual production, 240 W/module and 0,45 /Wp

9 Inprecisely cured EVA Manufacturer B and D are obviously not in control of their lamination process. EPCs are likely to stop PV power plant projects facing such results. Expected loss: 450 k per planned MWp as modules will not be sold plus handling and transportation. Overcuringcompared to EVA gel content eats up precious equipment time. An additional 5 10% gel content needs easily 1 2 min additional curing. Adjusting cycle time* accordingly will increase capacity by 7 %(14%)or spare every 14th (7th) shift. range of recommended EVA gel contents Counteraction: Close monitoring of lamination process and EVA gel content determination procedure. * Initially 15 minutes per lamination

10 Inadequate long-term DH stability Performance of manufacturer C (purple) is impressive, that of manufacturer A (green) just fine enough. The dramatic drop in performance puts a slight question mark behind manufacturer B (yellow). For modules from manufacturer E (pink) the probability of failing after 10 years in the field is very high. The investor faces a loss of 50 % of the expected turn-over of 20 years (2.5Mio / MWp). The manufacturer faces 450 k per MWp replacement costs plus handling and transport. But what is wrong with manufacturer D (blue)? One module performs just fine, the other fails after 2000 h DH. Unstable production process, different materials, outsourced production? Counteraction: thorough material qualification, tight production monitoring, no outsourcing. today s minimum requirement for DH stability

11 Microcracks and broken cells The client s point of view: Modules with broken cells are usually not accepted by clients as they imply poor craftsmanship in module production. Financial loss: no sales at all Clients typically only accept modules with a very low number of microcracks as they do not know which microcrack will evolve into a safety hazard or power loss. Financial loss: no sales at all. The manufacturer s point of view: Typically internal pass criteria for number of broken cells and microcracks exist for PV modules. A module that does not pass the final inspection does cost the manufacturer 0,5 /Wp or 120 /module. A cell that does not pass incoming goods control does cost the manufacturer 0,38 /Wp or 1,6 /cell. The earlier a failure is detected the less expensive it is! Counteraction: incoming goods inspection, continuous quality assurance in production.

12 Production optimization as a result of QA and QM We have seen that QA and QM involves at least the check for non-conforming materials and processes, monitoring and tightening of process parameters and long-term reliability testing. We have also shown that these activities result in increase of yield, through-put and turnover. And this is basically what production optimization is all about. And tools to do so already exists. They have been developed e. g. in the automotive and semiconductor industry and can be easily adapted for the use in solar: Non conforming material or product disposition by MRB (Material Review Board) Process distribution can be tightened by e.g. L6S methods (Lean Six Sigma) Process change requests and their roll-out needs to be reviewed and documented by PCRB (Process Change Review Board) Standardized problem solving processes (like 8D) Introduction of accelerated ageing conditions with acceleration factors beyond DH like HAST (Highly Accelerated Lifetime Testing) to allow short feedback cycles in case of material, process or product changes With more tools available (e. g. DoE, SPC, CP/Cpk) Prerequisite: Production optimization starts with a well developed MES (Manufacturing Execution System) and an appropriate data base storing process for Key Input/output Variables (KIV/KOV), materials (batches), process revisions, operators, equipment, maintenance, etc.

13 Conclusion Failures long thought overcome also include broken cells, microcracks and finger interruptions apart from yellowing. New phenomena have evolved. We have derived the financial losses for investors and manufacturers for yellowing, inexact STC determination, insufficiently cured EVA, inadequate long-term DH stability and broken cells /microcracks. They can amount to more than a million Euro. Counteraction to prevent these quality issues to occur are standard quality assurance and quality management tools. Their costs may amount to several ten thousand Euro, hardly more than 10 % of the above mentioned financial losses without counteractions. Costs for QA and QM are easily financed by the savings due to avoided failures and additional production capacities. They are not too high! QA and QM automatically result in production optimization with its increased yield, through-put and turnover. The tools are available and ready for adaptation! Thank you for your attention! PICON looks forward to supporting the implementation and optimization of QA and QM.