Despite their high efficiency, concentrator solar cells have one major issue: they
produce a significant amount of waste heat. This leads to excessive temperatures inside
the cell, which reduces the efficiency of the electrical conversion and shortens the
life of the cell. Therefore, efficient cooling solutions are needed. In this paper,
a novel approach for the cooling of concentrator solar cells is proposed. Compared
to the solutions found in the literature, the proposed solution incorporates microchannels
into the backside metal contact layer of the solar cell. This way, there are no restrictions
regarding the semiconductor material, no decrease in mechanical stability, and no
thermal interface material is required. First, the appropriate channel geometry and
theoretical performance were determined for a 2 × 2 cm2 solar cell using Siemens FloTherm
computational fluid dynamics and an in-house analytical modelling tool written in
ANSI C. The paper describes the step-by-step iterations of the design and the manufacturing
process that were necessary to reach the theoretically calculated ideal performance.
Hydrodynamic and thermal measurements were performed generation by generation, taking
into account the results obtained from simulation results. For the latest generation,
comparing the hydrodynamic properties at a flow rate of 80 cubic centimeters per minute,
the difference between the simulated and the average difference of measured pressure
drop values is 2.29 %. The measured data confirms that the partial thermal resistance
of the microchannel-based cooling device is 0.32 K/W at a maximum applied pressure
drop of 1 bar. This means that the temperature increment for a solar cell with a surface
area of 4 cm2 exposed to a concentration level of 100 suns is only 11.5 K.
