Thin-Film Insulated Capacitor Module for Compact Inverters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional capacitor modules for electric drive systems in vehicles and industrial applications are excessively thick due to the use of resin cases for insulation, leading to increased size and mountability issues for inverter and motor modules.
Innovation Solution
A capacitor module design featuring a metal case with integrated film capacitor cells and bus bars, utilizing a thin electrical insulating film on the inner surface of the metal case and bus bars, along with resin guards for enhanced insulation and reduced thickness, while maintaining high electrical insulation properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a resin case is used to electrically insulate film capacitor cells, then electrical insulation is achieved, but the thickness of the capacitor module increases
Solution Approach 1:
The patent replaces the conventional resin case with a thin film insulating structure. Specifically, an insulating film is formed on the inner surface of the metal case or on the outer surfaces of the bus bars, providing electrical insulation with minimal thickness. This thin film approach maintains the required insulation properties while dramatically reducing the overall thickness of the capacitor module compared to traditional resin case structures.
Solution Approach 2:
The patent extracts and removes the resin case from the capacitor module structure entirely. By eliminating the resin case and replacing it with thin film insulation integrated into the metal case or bus bars, the design removes the thickness-contributing component while preserving the essential electrical insulation function through more efficient insulating structures.
2Temperature
If thermal interface material is interposed between the resin case and inverter case for heat dissipation, then thermal management is improved, but the thickness and size of the inverter device increase
Solution Approach 1:
The patent removes the resin case that would normally be positioned between the capacitor cells and the inverter case. By eliminating this intermediate structure, the thermal interface material can be applied directly to the metal case, reducing the overall thickness and volume of the inverter device while maintaining effective heat dissipation pathways from the capacitor cells through the metal case to the cooling system.
Solution Approach 2:
The patent merges the functions of the resin case and thermal interface material by integrating insulation and thermal management directly onto the metal case structure. The thin film insulating layer is formed on the metal case surface, allowing thermal interface material to be applied in the same location, combining multiple functions into a compact integrated structure that reduces overall device size.
3Reliability
If a conventional resin case structure is used, then electrical insulation is provided, but the mountability of the inverter device on vehicles deteriorates
Solution Approach 1:
The patent employs thin film insulating structures instead of bulky resin cases, enabling the capacitor module to have a compact form factor that fits better within the spatial constraints of vehicle mounting applications. The thin film insulation provides the necessary electrical isolation while allowing the overall device dimensions to be reduced for improved vehicle integration and installation flexibility.
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 reduces the overall thickness of the capacitor module by 34.5%, enabling a more compact and mountable inverter device and motor module, improving the integration of electric drive systems in vehicles.
Implementation Method 1
an electrical insulating film formed at least on an inner surface of the metal case or each of outer surfaces of the pair of bus bars
Data Source
AI summary
Provided is a capacitor module in which a plurality of film capacitor cells and a pair of bus bars are housed in a metal case to be integrated with a resin added in the metal case, and an electrical insulating film is formed at least on an inner surface of the metal case or each of outer surfaces of the pair of bus bars. The capacitor module is provided in an inverter device including an inverter circuit that converts DC power into AC power. The inverter device is provided in a motor module including an AC motor rotationally driven by AC power supplied from the inverter device, and the motor module is provided in a vehicle including an electric drive system.