EV Inverter Power Module Substrate Layout for Thermal Isolation
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Solution Overview
Problem
Inverters for electric vehicles face challenges with thermal management due to heat generation by power modules, which can lead to incorrect operation and overheating, compromising the inverter's performance.
Innovation Solution
A power module design incorporating a first and second substrate with an electrically conductive spacer and a flex circuit to manage thermal characteristics and electrical connections, using materials like silicon nitride and metal for improved heat dissipation and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If power modules are used to generate high power in inverter, then power output is improved, but heat generation increases causing thermal management issues
Solution Approach 1:
The power module is divided into multiple semiconductor dies (e.g., IGBTs and diodes) mounted on separate substrates, allowing heat to be distributed across multiple mounting points and thermal paths rather than concentrated in a single location, thereby improving thermal management while maintaining high power output
Solution Approach 2:
Thermal interface materials and heat sinks are introduced as intermediary components between the semiconductor dies and the external environment, facilitating efficient heat transfer from the power-generating components to the cooling system, thus managing thermal load while preserving power generation capability
2Volume of moving object
If substrates are placed close together to reduce module size, then compactness is improved, but thermal interference between substrates increases
Solution Approach 1:
The first and second substrates are positioned asymmetrically with non-uniform spacing, where the spacing varies in different regions to create optimized thermal pathways. This asymmetric configuration allows compact overall dimensions while maintaining sufficient thermal separation in critical areas to prevent thermal interference between substrates
3Reliability
If electrically conductive spacers are used to connect substrates, then electrical connectivity is improved, but thermal conduction between substrates increases causing heat transfer
Solution Approach 1:
The electrically conductive spacers are designed with non-uniform cross-sectional areas along their length, featuring a larger cross-section in regions where electrical connectivity is prioritized and a smaller cross-section in regions where thermal isolation is needed. This local variation in geometry allows the spacers to provide adequate electrical connection while limiting thermal conduction between substrates
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
The design enhances thermal management and electrical connectivity, preventing overheating and ensuring reliable operation of the inverter by maintaining optimal temperature conditions.
Implementation Method 1
an electrically conductive spacer connecting the first substrate to the second substrate
Implementation Method 2
the middle section includes a ceramic, and the outer surface and the inner surface of the first substrate includes a metal
Data Source
AI summary
A power module includes: a first substrate having an outer surface and an inner surface; a semiconductor die coupled to the inner surface of the first substrate; a second substrate having an outer surface and an inner surface, the semiconductor die being coupled to the inner surface of the second substrate; and a first electrically conductive spacer coupled to inner surface of the first substrate and to the inner surface of the second substrate.