EMCORE receivers for CPV system development

Abstract

High-efficiency solar cells used in Concentrator Photovoltaic (CPV) Systems require reliable, high-performance electrical, thermal and optical interfaces. EMCORE has developed standard CPV receivers that provide these interfaces. These standard designs provide a tool for CPV system developers to validate their novel system designs without the cost and schedule impact associated with custom receiver design. Standard receivers based on EMCORE's 1cm × 1cm and 0.5cm × 0.5cm triple junction solar cells will be reviewed. The standard receivers incorporate design rules developed by EMCORE's CPV system development team and are implemented using Curamik's aluminum oxide direct-bond-copper (dbc) substrates. The designs include Curamik's dimple technology for stress relief. The dbc substrates provide the high electrical stand-off and low resistance required for CPV applications. EMCORE's designs incorporate box connectors for wire interconnection to the receivers and a bypass diode that allows for string operation during partial shadow conditions. All components are attached using a solder reflow process that provides low void content bonding and excellent thermal conductivity between the solar cell and its substrate. Data gathered during receiver assembly, including x-ray data showing void content, will be reviewed. Methods and results for thermal resistance measurements will be presented. In addition we will review features included in the dbc that allow for component placement control. Receiver performance data as measured by HIPSS (High-Intensity Pulsed Solar Simulator) at 1000X concentration will also be reviewed. EMCORE is currently providing pre-qualification samples of these receivers to CPV system developers while qualification of the receivers is completed. The qualification test plan for the receivers will be reviewed and preliminary data from the qualification tests will be presented.