ECN replaces silver by copper in solar module

Friday December 6, 2013 21:12

ECN has designed and tested integrated Metal-Wrap-Through (MWT) solar modules with solar cells that use copper instead of silver. They perform well and they are more sustainable and affordable compared to solar panels that use solar cells with silver.

A smalls-scale MWT module. At the front, flat wires are soldered onto the cell. At the rear, copper lines are attached to the cell. They make contact with a conductive copper foil by means of a conductive adhesive.

Not enough silver

There is enough sun to supply the entire globe with solar energy, but there is not enough silver. Silver is the scarcest material that is used in solar modules for the conductive lines on the cells. It is expected that, along with the increasing scarcity, the price of silver will increase and hence the price of solar cells and modules. Instead of silver threads on silicon wafers, ECN applied conductive copper foil on the MWT solar modules. The technology can also be used in traditional modules, but the MWT cells and panels developed by ECN offer a higher efficiency. The result is an integrated design of an MWT module with cells that no longer use silver.

Mechanical adhesion

What is special about the ECN study is not only that copper is applied in the solar cell, as this has already been done before, but that the mechanical adhesion of the copper solar cell in the module and the connections inside have been designed and tested. The lab-scale model performs well and has a capacity that is comparable to MWT cells with silver. Moreover, the design is sustainable and strong. Even after having been subjected to 200 thermal cycles of -40 to +85°C , the model hardly showed any deterioration in performance.

Industrial production

The study was conducted for the Seventh Framework Programme of the European Union. ECN published an article on the topic in Photovoltaics International, on the occasion of the EPV-SEC conference, which was held in Paris last September. ECN will now scale up the model together with solar cell manufacturers abroad and with Dutch manufacturers of production equipment for solar panels (e.g. MECO, Tempress and Eurotron). The ultimate goal is to realise industrial production of MWT solar modules in which silver is replaced by copper. Depending on how the silver price evolves, ECN expects industrial production to be feasible within two to five years. This means that more affordable solar modules become available to the consumer, that there will be more market opportunities for businesses and less depletion of the environment.

Read the article in Photovoltaics International.

Are you interested in the deployment of copper in solar modules? Jan Bultman will gladly tell you more about it. Give him a call at +31 (0)88 515 4786.

Category: November, Solar Energy, Corporate