Stacked Leadframe Assembly for CPV Thermal Dissipation and Voltage Isolation
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Solution Overview
Problem
Current concentrated photovoltaic (CPV) receiver packages struggle to achieve high thermal dissipation and voltage isolation while maintaining low manufacturing costs and high reliability.
Innovation Solution
A leadframe assembly with multiple stacked frames is used, where the top frame provides electrical interconnects and a connection for hook-up wires, the middle frame maintains alignment and electrical connections, and the bottom frame incorporates thermally conductive but electrically isolating material, all encapsulated to reduce electrical resistance and enhance thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic substrate is used to provide thermal dissipation and voltage isolation, then thermal performance and electrical isolation are improved, but manufacturing complexity and cost increase
Solution Approach 1:
The leadframe is divided into multiple separate frames (first frame, second frame, third frame) that are stacked and soldered together. Each frame performs specific functions: the first frame provides electrical interconnects, the second frame maintains alignment and provides additional thermal path, and the third frame provides thermal dissipation with electrical isolation. This segmentation allows manufacturing using standard PCB and soldering processes rather than requiring complex ceramic substrate fabrication.
Solution Approach 2:
The invention uses a composite structure combining multiple metal frames with different properties. The leadframe materials (copper, copper alloy, or aluminum) provide both thermal conductivity and structural integrity, while the stacked configuration creates a composite thermal management system that achieves ceramic-like performance through assembly rather than material substitution.
2Reliability
If multiple frames are stacked to provide thermal dissipation and voltage isolation, then thermal performance and electrical isolation are improved, but device complexity increases
Solution Approach 1:
Multiple functions are merged into the stacked frame structure: electrical interconnection, mechanical alignment, thermal conduction, and electrical isolation are all achieved through the same assembly. The solder joints between frames simultaneously provide electrical connection and mechanical bonding, while the frame geometry provides both structural support and thermal pathways, reducing the need for separate components.
Solution Approach 2:
The leadframe structure serves multiple purposes: it provides electrical interconnects for the photovoltaic cell, acts as a mechanical support structure, conducts heat away from the cell, and provides voltage isolation between different electrical potentials. This multi-functionality reduces the overall component count and simplifies the assembly process compared to using separate specialized components for each function.
3Ease of manufacture
If traditional leadframe solutions are used, then manufacturing cost is reduced, but thermal dissipation and voltage isolation performance are insufficient
Solution Approach 1:
The invention transitions from a traditional single-plane leadframe to a three-dimensional stacked configuration. By adding the vertical dimension with multiple stacked frames, the thermal dissipation capacity is significantly increased while maintaining compatibility with standard planar manufacturing processes. The stacked frames create additional thermal pathways and increase the effective heat sink area without requiring complex manufacturing techniques.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration achieves superior electrical and thermal performance, supporting high voltage isolation and efficient power output while reducing manufacturing complexity and costs.
Implementation Method 1
Photovoltaic cells or dies are a well known means for producing electrical current from electromagnetic radiation
Implementation Method 2
the bottom frame incorporates thermally conductive but electrically isolating material
Data Source
AI summary
In accordance with the present invention, there is provided a CPV package which comprises a leadframe assembly, such leadframe assembly including multiple frames stacked on top of each other. A top frame of the leadframe assembly provides the electrical interconnect between the top or front surface of the receiver die and the bypass diode required to complete the circuit. The top frame also provides hook up wire interconnect pads for the completed CPV package. An exposed bottom surface of a bottom frame of the leadframe assembly defines a heat spreader which assists in thermal management. The fabrication of the CPV package to include multiple frames stacked on top of each other provides high thermal dissipation and high voltage isolation, while at the same providing a high level of reliability with a comparatively low manufacturing cost.