​​​​FAQ – Back-Contact solar modules​​

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What are the advantages of BC modules?

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• Appearance: no silver busbars on the front.

• ​Output: More light reaching the active cell area means higher yield.

• Lower series resistance means higher electrical efficiency.

• Better heat dissipation: reduces cell temperature and power loss in hot conditions.

• Robust against partial shading: no hotspot formation and no additional power losses.​

• Lower thermal load when individual cells are shaded.​

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What is the difference between HBC, IBC, BC and xBC?

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​BC (Back Contact) is the umbrella term for solar modules in which all electrical contacts are located on the rear side of the solar cells. This keeps the front free of metallic grid lines and busbars. The result is more power per m², a homogeneous appearance and increased shading tolerance.

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• IBC (Interdigitated Back Contact) is a special BC variant in which the positive and negative contacts interlock on the rear side.

• HBC, TBC, HPBC and xBC are further BC variants that differ in cell technology, material or passivation – for example Heterojunction, TOPCon or Hybrid Passivated.

• Technically, all of them belong to the back-contact technologies – the difference lies in the details of the cell design, not in the basic function.

 

Why do Back-Contact solar modules perform better than conventional solar modules under partial shading?

Back-contact modules carry the current exclusively via the rear side of the cell. As a result, current flow is not directly interrupted by surface shading from leaves, branches or chimneys.
 

• BC modules have lower yield losses compared with front-contact modules.

• During brief or partial shading, the energy yield remains more stable.

• BC modules only switch to bypass once 6 half-cells in the module string are shaded.

• Fewer yield losses from everyday interfering factors mean more electricity.

• Less stress on the PV modules from hotspots increases the service life of your PV system.

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Which roofs are ideal for Back-Contact modules?

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​In principle, all roofs – whether with no shading or only slight shading. Unlike conventional, front-contact solar modules, BC modules are ideal for:

• Roofs with chimneys, dormers or antennas.

• East/west orientation with changing light incidence

• Roofs located near trees (foliage, cast shadows)

• Buildings with temporary shading from adjacent structures

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Are Back-Contact solar modules the solution for shaded locations?

They are not a miracle cure for full shading – but they offer a clear advantage under partial shading, which occurs regularly on most roof areas. It is precisely there that they make a difference to the annual yield.

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Can Back-Contact modules be bifacial?

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Yes, SOLYCO Back‑Contact modules are bifacial. The SOLYCO 108nBC.6 / 485, for example, uses light from both the front and rear side and can therefore generate up to 30 % more yield.

 

What disadvantages does back-contact technology have?

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Due to the elaborate manufacturing process, Back‑Contact modules are somewhat more expensive, which results from the more complex production. BC cells require more process steps and the latest production standards.