Reconditioning instead of recycling of damaged solar cells

Fig. 1: ITS uses reconditioned solar cells to fabricate new PV modules which have been certified by TÜV Rheinland according to IEC standards; Pictures:ITS

The company upgrades off-spec-solar cells to full efficiency by a laser-supported process. This is a win-win situation for manufacturers, customers, and the environment. Close to the German Solar Valley in Halle, Germany, the Norwegian company Innotech Solar (ITS) has opened its second European  cell processing facility in Halle, Germany. Local PV cell-producing companies, such as Q-Cells and Bosch, cooperate with ITS. The Initial plans are to process up to 4,000 solar cells from different manufacturers per hour.
Even in a well-operated production process, a considerable number of cells fail to pass demanding quality tests. Given the tight margins, the energy and material expenditure involved in manufacturing cells, it is certainly beneficial to use 100% of the cells produced. ITS technology offers a way to increase the overall efficiency of the production process. After processing, the cells are used to make ITS solar modules. These modules have the same performance and quality as conventional high-power modules. They are environmentally friendly, since initially rejected cells regain their full performance capacity.

Thermal imaging exposes the culprit

Fig. 2: The surface area isolated by the process is generally less than 0.05% of the overall solar cell surface area Facts for Decision Makers Increase the overall efficiency Close to the German Solar Valley in Halle, Germany, the Norwegian company Innotech Solar (ITS) has opened its second production facility in Europe. The company upgrades non-prime solar cells to full efficiency by a laser-supported process. After processing the cells are used to make solar modules. This reconditioning increases the overall efficiency of the production process.

One of the origins of faults is seen in so-called shunts caused by impurities in the silicon used to manufacture poly- and monocrystalline solar cells, among other factors. These shunts can be detected with an infrared camera because the shunt areas of the cells become warm on passage of an electric current. Once found, the second step is to deactivate the shunts with laser technology. One of the greatest challenges facing researchers was to find the right laser-parameters. All cells with major impurities which could not be handled by the main laser process formerly had to be rejected, even if a considerable part of the cell was fully functional.
New production steps have made it possible to deal with even larger impure zones: a laser cuts off the non-functional parts of the cell so that only the fully-functioning remaining halves or thirds are further used. Even more cells that recently would have been rejected can now be used for the production of high-quality modules, consequently making cell and module production even more efficient and environmentally friendly. Multi-stage testing and optimization processes guarantee a high performance level comparable to that of conventional modules.

Fig. 3: Adjustment and processing the solar cells

Close to the cell manufacturers
If cell manufacturers were to sell the unprocessed cells elsewhere, there is a risk that the cells would end up being installed in low-quality modules, which, in turn, would harm the image of the manufacturer if they reached the market. ITS makes sure that unprocessed cells are not distributed in an uncontrolled manner. It is not profitable for individual manufacturers to develop their own cell optimization capacities, because the volume of cells requiring optimization is too low. An example of cooperation is the long-term strategic partnership with Q-Cells and Bosch. At Halle ITS has invested around € 20m and created 80 jobs. Another 50 jobs will be added in the course of further expansion. The production facility will have a total floor space of 7,000 m2.

“The ITS facility at Halle is located right at the centre of European -solar competence. Strong local -support for ITS was also a key -factor favoring our choice of Halle”, says Tommy Strömberg, Managing Director of ITS Halle

At the foundation stone laying ceremony, Thor Christian Tuv, CEO of ITS, explained the choice of Halle as a location: “Our decision was based on the infrastructure, such as the direct connection to the highway, state and municipal funding, availability of trained personnel, and the efficient solar competence network in the region.”  The whole process of investment – starting with the search of site to the phase of implementation – has been assisted by Investment and Marketing Corporation of Saxony-Anhalt (IMG). But ITS is not only entering markets in Europe, as in Italy, Spain, and Great Britain. The company is also planning to open a location in the USA in the second half of this year. In Asia, it has meanwhile opened a logistics center in Hong Kong, in addition to its existing sales and purchasing office in Shanghai. In China, the company is not only purchasing large quantities of off-spec solar cells to be optimized at its European production sites in Narvik and Hallebut is also processing and selling customized cells whose properties preclude their use in grid-connected solar modules.
These cells are cut with a laser procedure and then used in modules for off-grid solar power supply, or they are sold to customers in Asia to be used in solar consumer applications. These include small applications such as cell phone chargers, solar toys, solar street lights, and garden lights.

EU PVSEC 2011: ITS Hall B6 – C28
EU PVSEC 2011 IMG Hall B6 – A37