Solar Power 2.0 (Development of Cost-Effective, High-Efficiency N-Type Concentrator Solar Cells for Low-Concentrated CPV)

  • Funding institution: DLR, German Federal Ministry of Education and Research (BMBF, as part of the "Eurostars 2" programme, Horizon 2020)
  • Support code: 01QE1511
  • Total funding: € 800,000.00 
  • Duration: 06/2015 to 09/2016
  • Consortium: LineSolar and ISC Konstanz
     

Starting Point

The goal of technological developments in the photovoltaics industry is to reduce costs in order to achieve grid parity. This is becoming ever more urgent, as incentives on the different leading PV markets are continuously decreasing – the consequence being that existing technologies will completely disappear from the market within the next two to three years. However, if the production costs accompanying the ever more complex cell and module processes can be kept low, the pursuit of higher cell performance will lead to lower PV module costs in euro per kilowatt peak. The savings from the so-called "cost of balance of systems" then permit lower electricity generation costs (€/kWh).

Currently, the solar cells themselves still account for over 50% of the module costs. Therefore, concentrator photovoltaics is a promising concept that could reduce module costs at a high efficiency level. In this concept, light that radiates onto the front of the module is focused onto small solar cells optimised for high light intensity through lenses, which ideally cover the entire surface of the module. This significantly reduces the number (and total surface) of solar cells required for each module surface. In addition to the reduced silicon consumption, more complex process sequences can thus be used for solar cell production without driving module costs higher.
 

Objectives

With this in mind, we want to develop and implement the following innovations with Solar Power 2.0:

  • a more cost-effective process for thin n-type IBC solar cells with an efficiency of 23% for simple and 26% for 40-fold concentration,
  • a simple lens system that can concentrate the light 40-fold,
  • reflectors that are able to make even diffused light usable, and
  • a cost-effective module with efficiency of 26% and production costs of 0.22 €/Wp.
     

Description

As part of project Solar Power 2.0, innovative concentrator solar cells will be developed from monocrystalline n-type silicon (c-Si). An IBC cell concept based exclusively on industrial processes (the ZEBRA concept developed at ISC Konstanz) serves as a starting point for this.

When it comes to solar cells, all their relevant elements will be optimised as part of the project in terms of their requirements in concentrated sunlight. Aside from optimising the doping of the emitter and back surface field, particular attention will also be paid to investigating different technologies for producing the metal contacts (e.g. screen printing and bonding). The additional laser process steps required for the solar cell concept that is being devised here will also be developed and optimised as part of the project.

The other main work package addresses the elements required for producing a cost-effective concentrator module with a high efficiency level. The central issues for this are developing a simple lens system and cost-effective process for connecting the cells to one another electrically, whilst at the same time ensuring the highest efficiency possible.

With efficiency of up to 26% and module production costs reduced to 0.22 €/Wp, the concentrator modules being developed in project Solar Power 2.0 will enable a significant reduction in electricity generation costs (€/kWh), thereby making an important contribution to the wider dissemination of photovoltaics.