Cells on the back of double-glass modules

Dual-glass type modules (also called double glass or glass-glass) are made up of two glass surfaces, on the front and on the rear with a thickness of 2.0 mm each. Some manufacturers, in order to reduce the weight of the modules, have opted for a thickness of 1.6 mm. DualSun has chosen to stay with a thickness of 2.0 mm for reasons explained below.

The double glass module design offers not only much higher reliability and longer durability but also significant Balance of System cost savings by eliminating the aluminum frame of conventional modules and frame-grounding requirements. The application of double-glass modules covers multiple markets including utility, residential and commercial.

Mechanical constraints on cells: the fact that the structure of the double glass modules is symmetrical implies that the cells are located on a so-called neutral line, the upper part of the module being in compression during a downward mechanical load and the lower glass surface being in tension.

Recently several double-glass (also called glass–glass or dual-glass modules) c-Si PV modules have been launched on the market, many of them by major PV manufacturers. These modules use a sheet of tempered glass at the rear of the module instead of the conventional polymer-based backsheet. There are several reasons why this structure is appealing.

The thickness of the front glass generally used for this type of structure is 3.2 mm. Dual-glass type modules (also called double glass or glass-glass) are made up of two glass surfaces, on the front and on the rear with a thickness of 2.0 mm each.

In the case of a glass-backsheet module, not only is the upper glass layer thicker (3.2 mm versus 2.0 mm) but also this layer is fully tempered glass, whereas in the case of a thickness of 2.0 mm, the glass is only semi-tempered due to technical limitations of the tempering process.