Uniformly heated cell

In an infrared image, a uniformly heated cell is one whole cell that is clearly warmer than the cells around it. The heat is spread evenly across the cell instead of sitting in one small spot. This hot cell pattern usually shows up in monocrystalline cells. Shading or cracking causes current mismatch and pushes the weak cell into reverse bias, so it dissipates power as heat. A small, localized hotspot points more to multicrystalline cells. Possible causes are shading, a defective or shunted cell, a delaminated cell, or other internal cell problems. Power lost to shading, such as from a leaf or lichen, may not be permanent. If only part of the cell is warm, suspect a broken cell or a disconnected interconnect instead. These usually come with a sharp drop in power and fill factor. Warm cells along the bottom frame or in a patchwork pattern, in modules near the negative end of the string, point to potential induced degradation (PID). Check first: look at the module for shading or soiling and clean it if needed, then take a new IR image to see whether the heating is still there. Gradients of 10 to 20 °C are not a problem for now but can grow over time. Keep these modules on the regular thermography inspection list. If a hot cell is left in place, it can lead to discoloration, interconnection failures, cell cracks, delamination and loss of electrical insulation.

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• sentence 6: support check: partial - u9 says visual inspection and cleaning needed for cell mismatch, but does not state a check-first order or re-imaging after cleaning. -->