Vascular Cooled Capacitor Assembly with Sacrificial Channel Network
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Solution Overview
Problem
Capacitors face challenges in high-temperature environments due to their temperature sensitivity, particularly in applications like automotive traction power inverters, where solid electrolytic capacitors have high equivalent series resistance, limiting their effectiveness, and increasing heat removal capacity through larger busbars adds size, mass, and cost.
Innovation Solution
A vascular cooled capacitor assembly with a network of channels formed by deflagration of a sacrificial material, which allows for efficient cooling fluid flow through the capacitors and busbars, providing effective heat management without increasing size or cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If solid electrolytic capacitors are used in high-temperature environments, then cost and capacitance per unit volume are improved, but equivalent series resistance increases and effectiveness is limited
Solution Approach 1:
The cooling system is segmented into multiple channels distributed across the capacitor assembly, with individual channels positioned inside central axial passages, around outer peripheries, and between capacitors. This segmentation allows efficient heat removal from different regions without increasing equivalent series resistance.
Solution Approach 2:
A cooling fluid intermediary is introduced to transfer heat from the capacitors and busbars to the external cooling system. The fluid circulates through the channel network, absorbing heat from high-temperature regions and transporting it away, thereby maintaining capacitor performance in high-temperature environments.
2Temperature
If larger busbars are provided to increase heat removal capacity, then heat management is improved, but size, mass and cost increase
Solution Approach 1:
The cooling solution transitions from increasing busbar cross-sectional area to creating a three-dimensional network of cooling channels. Channels are positioned inside central axial passages, around outer peripheries, and between capacitors, utilizing spatial dimensions rather than simply enlarging busbar mass to achieve heat removal.
Solution Approach 2:
The patent employs a liquid cooling system where cooling fluid flows through the channel network to remove heat. This hydraulic approach replaces the need for larger solid busbars, using fluid dynamics to efficiently transport heat away from capacitors and busbars without increasing their mass.
3Temperature
If a network of cooling channels is formed by deflagration of sacrificial material, then heat management efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
Sacrificial material components are pre-positioned within the encapsulant at specific locations corresponding to desired channel paths. These pre-placed components are then ignited to create the cooling channels, eliminating the need for complex post-manufacturing channel formation operations.
Solution Approach 2:
The deflagration of sacrificial material, which could be considered a destructive process, is converted into a beneficial manufacturing step. The controlled combustion creates the desired cooling channel network within the encapsulant, simplifying what would otherwise require complex drilling or machining operations.
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 vascular cooled capacitor assembly effectively manages heat in high-temperature environments, enhancing the performance and reliability of capacitors in applications like automotive traction power inverters by maintaining efficiency and reducing thermal stress without adding size or cost.
Implementation Method 1
a network of channels enveloped within the encapsulant and formed by deflagration of a sacrificial material
Implementation Method 2
efficient cooling fluid flow through the capacitors and busbars, providing effective heat management
Implementation Method 3
cooling fluid supply and return system in fluid communication with the at least two cooling fluid interfaces
Data Source
AI summary
A vascular cooled capacitor assembly includes a plurality of capacitors having respective first and second leads, first and second busbars disposed in electrical contact with the first and second leads, an encapsulant enveloping the capacitors and a respective major portion of each of the first and second busbars, and a network of channels enveloped within the encapsulant and formed by deflagration of a sacrificial material. The network has at least one network inlet and at least one network outlet, each of which is configured for sealable engagement with a cooling fluid system. A branch of each channel is positioned inside a central axial passage of a capacitor, around an outer periphery of a capacitor, and/or between two capacitors. A housing may enclose the capacitors, the channels and major portions of the first and second busbars.