DC Link Capacitor Cooling System With Integrated Heat Sink
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Solution Overview
Problem
Existing DC link capacitors in electric vehicles face challenges with heat dissipation, leading to sub-optimal lifetime performance due to high thermal impedance caused by the lack of thermally conductive material in the capacitor housing.
Innovation Solution
Integration of a heat sink with a dielectric thermal interface material into the DC link capacitor system, which allows for thermal coupling with an active coolant domain to dissipate heat effectively, thereby reducing thermal hotspots and maintaining the capacitor within the safe operating boundary of the dielectric material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If traditional capacitor housing is used, then manufacturing is simple, but thermal dissipation is insufficient leading to high thermal impedance
Solution Approach 1:
The patent merges the capacitor housing with a heat sink into a single integrated structure. The housing itself is designed with thermally conductive features that act as heat dissipation pathways, eliminating the need for separate heat sink components while improving thermal management.
Solution Approach 2:
The patent introduces a thermally conductive adhesive as an intermediary material between the capacitor body and the housing/heat sink structure. This adhesive serves dual functions: electrical insulation and thermal conduction, facilitating efficient heat transfer from the capacitor to the housing while maintaining electrical isolation.
2Duration of action of stationary object
If higher operating temperatures are allowed, then capacitor lifespan increases, but thermal hotspots may exceed dielectric material boundaries
Solution Approach 1:
The patent incorporates thermal management design that creates a feedback mechanism through the integrated heat sink structure. The heat sink continuously draws heat away from the capacitor, preventing thermal runaway and ensuring that operating temperatures remain within safe boundaries while maximizing lifespan.
Solution Approach 2:
The patent changes the thermal parameters of the system by introducing thermally conductive pathways and materials. This allows the capacitor to operate at higher temperatures without exceeding dielectric material limits, effectively shifting the operating temperature range to optimize lifespan.
3Temperature
If larger capacitance or higher voltage rated capacitor is used, then thermal hotspots are controlled, but device size and cost increase
Solution Approach 1:
The patent extracts the thermal management function from the capacitor core and implements it in the housing structure. By separating the capacitance function from the thermal management function, the capacitor itself can remain compact while the housing provides the necessary heat dissipation capabilities.
Solution Approach 2:
The thermally conductive adhesive acts as an intermediary that enables efficient heat transfer without requiring larger capacitor components. This allows thermal hotspot control to be achieved through the housing rather than through oversized capacitor elements.
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 solution enables the capacitor to function at higher operating temperatures without requiring a larger capacitance or higher voltage rating, thereby extending its lifespan and improving thermal conductivity.
Implementation Method 1
a dielectric thermal interface material is positioned at various locations in the system which may include: between busbars, between the busbar and the heat sink and between the heat sink and the chassis
Implementation Method 2
heat is dissipated from the capacitor through the chassis and into the active flowing coolant passing through a cooling domain in the chassis
Data Source
AI summary
A DC link capacitor cooling system having an integrated heat sink disposed across a bottom surface of a DC link capacitor with a dielectric thermal interface material covering the integrated heat sink, and a chassis contacting the dielectric thermal interface material, wherein the chassis has an active fluid coolant domain therein.