What is that component ?

[Laval]

This is a standby power supply that was in a UPS. It works perfectly fine but I'm curious as to what the component shown on the picture is. I'm talking about the aluminium block just beside the DC-DC switching IC.

This is only connected to the ground plane and to the solder lines on the other side of the board. Its designation is HS5 which would suggest a heat sink but there is no component mounted on it. If it is a heat sink, is it there to dissipate heat from that area of PCB ?

[coromonadalix]

i think they added thermal mass dissipation with this part,  to help the smps  ic  to dissipate

[Psi]

Probably cheaper than solving the heat issue with thicker copper PCB tracks.

Bit odd that its a solid block, be better to add some fins to it. But i guess that is an extra step that adds cost and was not required to get the thermal performance.

It may have been more about lowering a concentration of heat to keep the electrolytic caps at a safer temp. Rather than dissipating heat from anything in particular. Electrolytic cap lifespan falls like a rock at higher temps.