Ce Cell Engineering Gmbh

Fraunhofer-gesellschaft Zur Foerderung Der Angewandten Forschung E.v.

Hongming Zhao

Christian Hagendorf

Eckehard Hofmüller

Eve Krassowski

Stephan Grosser

Stefan Stöckel

Marko Turek

The invention relates to a method for improving the ohmic-contact behaviour between a contact grid and an emitter layer of a silicon solar cell, in which, in a treatment step, a treatment current flow having a current density of 200 A/cmto 20,000 A/cmin relation to the treatment section is induced while biasing and illuminating the silicon solar cell. The object of the invention is to improve the method for improving the ohmic-contact behaviour between a contact grid and an emitter layer of a silicon solar cell. In particular, it should be possible to quantify the improvement achieved by the method while implementing the method. Furthermore, any damage resulting from the application of unfavourable process parameters should be detected while the method is being implemented. This object is achieved in that a measurement step is carried out before and/or after the treatment step, and, in said measurement step, a measurement current flow having a current density of 1 mA/cmto 500 mA/cmis induced by illuminating the sun-facing side of the silicon solar cells and biasing, and a current strength of said measurement current flow is sensed using an ammeter and stored assigned to the respective measurement section.

Method for improving the ohmic contact behavior between a contact grid and an emitter layer of a silicon solar cell

The invention relates to a method for improving the ohmic-contact behaviour between a contact grid and an emitter layer of a silicon solar cell. The object of the invention is to propose a method for improving the ohmic-contact behaviour between a contact grid and an emitter layer of a silicon solar cell, in which the effects on materials caused by irradiation of the sun-facing side are further minimized. In addition, the method should also be applicable to silicon solar cells in which the emitter layer has a high sheet resistance. This object is achieved by first providing the silicon solar cell with the emitter layer, the contact grid and a rear contact, and electrically connecting the contact grid to one pole of a voltage source, then a contacting device that is electrically connected to the other pole of the voltage source is connected to the rear contact, and with the voltage source, a voltage is applied directed contrary to the forward direction of the silicon solar cell that is less than the breakdown voltage of the silicon solar cell and, when applying this voltage, a point light source is guided over the sun-facing side of the silicon solar cell and thereby a section of a subsection of the sun-facing side is illuminated and thus a current flow is induced in the subsection where the current flow relative to the section has a current density of 200 A/cmto 20,000 A/cmand acts on the subsection for 10 ns to 10 ms.

Method for improving ohmic-contact behaviour between a contact grid and a emitter layer of a silicon solar cell

Method for improving the ohmic-contact behaviour between a contact grid and an emitter layer of a silicon solar cell

Growing community of inventors

Halle/Saale, Germany

Hongming Zhao