Power Conversion Device Wire Harness Thermal Isolation
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Solution Overview
Problem
Existing power conversion devices for hybrid and electric vehicles face challenges in heat dissipation and space conservation due to the use of bus bars to connect capacitors and discharge resistors, leading to increased manufacturing costs and reduced heat dissipation efficiency.
Innovation Solution
The connection of capacitors and discharge resistors is simplified by using wire harnesses instead of bus bars, with the capacitors and resistors being connected via first, second, and third wire harnesses, which have higher thermal resistance than bus bars, thereby reducing heat transfer and improving heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bus bars are used to connect capacitor and discharge resistor, then electrical connection is reliable, but heat is transferred to capacitor and heat dissipation becomes inefficient
Solution Approach 1:
The patent introduces wire leads as an intermediary component between the discharge resistor and capacitor. These wire leads have higher thermal resistance compared to bus bars, acting as thermal barriers that prevent heat transfer from the discharge resistor to the capacitor while maintaining electrical connectivity. This resolves the contradiction by mediating between reliable connection and heat isolation requirements.
2Stability of the object's composition
If bus bars are used to connect capacitor and discharge resistor, then electrical connection is stable, but manufacturing complexity and costs increase due to welding requirements
Solution Approach 1:
The patent replaces the welding-based mechanical connection system with a terminal block-based electrical connection system. Instead of welding bus bars to the capacitor and discharge resistor, the invention uses terminal blocks with wire leads that can be mechanically connected and electrically connected separately, eliminating the need for welding operations and reducing manufacturing complexity.
3Loss of energy
If bus bars are used with large developed area for heat dissipation, then heat dissipation capacity increases, but device volume increases and space conservation becomes difficult
Solution Approach 1:
The wire leads serve as thermal intermediaries with inherent thermal resistance that limits heat transfer from the discharge resistor to the capacitor. This natural thermal barrier reduces the need for large heat dissipation surfaces, allowing compact design without sacrificing heat dissipation capacity.
Solution Approach 2:
The patent extracts the heat dissipation function from the connection structure itself. Instead of relying on large bus bar surfaces for heat dissipation, the invention separates the electrical connection function (performed by wire leads and terminal blocks) from the heat dissipation function (performed by dedicated cooling passages and heatsinks), enabling more efficient space utilization.
4Loss of energy
If cooling passages are made more complex to dissipate heat from bus bar, then heat dissipation efficiency improves, but device complexity and space requirements increase
Solution Approach 1:
The wire leads act as built-in thermal intermediaries that naturally limit heat transfer to the capacitor. This reduces the thermal load on the cooling system, allowing for simpler cooling passage designs that are less complex and require less space while still achieving effective heat dissipation.
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 enhances heat dissipation by minimizing heat transfer from the discharge resistor to the capacitor, reduces manufacturing costs, and conserves space, while allowing for easier assembly and quality inspection.
Implementation Method 1
a first wire harness 21 that is connected to a first terminal portion 1a of the capacitor 1 and connects the capacitor 1 and the discharge resistor 2
Implementation Method 2
which have higher thermal resistance than bus bars, thereby reducing heat transfer and improving heat dissipation
Data Source
AI summary
A capacitor and a discharge resistor can be connected using a simplified configuration without using a bus bar. A connection of a capacitor and a discharge resistor of a power conversion device are carried out using wire harnesses that form positive and negative lines. The capacitor and the discharge resistor are integrated by being directly connected using a first wire harness. A second wire harness is drawn out from a terminal portion electrically separated from a first terminal portion of the capacitor; and a third wire harness is drawn out from the discharge resistor, where the second wire harness and the third wire harness are fastened.