Vehicle Drive Cooling Circuit Isolation for Short-Circuit Prevention
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Solution Overview
Problem
In vehicle drive devices, the risk of a short circuit occurs when conductive temperature-control media enters non-conductive media, potentially causing electrical conductivity issues in electric motors.
Innovation Solution
A vehicle drive device with a temperature-control circuit that includes separate circuits for non-conductive and conductive media, featuring a heat exchanger and a protection cover to prevent the conductive medium from reaching the live parts, ensuring safe temperature control without electrical shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a heat exchanger is used to exchange heat between conductive and non-conductive temperature-control media, then temperature control efficiency is improved, but the risk of conductive medium entering the non-conductive medium and causing short circuits increases
Solution Approach 1:
The temperature control system is segmented into separate conductive and non-conductive media circuits with independent circulation paths. The heat exchanger enables thermal coupling while maintaining physical separation of the media, preventing contamination and electrical shorts while achieving efficient temperature control.
Solution Approach 2:
The heat exchanger acts as an intermediary device that transfers thermal energy between the conductive and non-conductive media without allowing direct contact between the two fluids. This mediator enables heat exchange while maintaining the electrical insulation properties of the non-conductive medium.
2Reliability
If separate temperature-control circuits for conductive and non-conductive media are used, then electrical safety is improved, but device complexity increases
Solution Approach 1:
While maintaining separate circulation paths for conductive and non-conductive media, the system merges the temperature control function through a common heat exchanger. This integration allows independent media circuits to work together efficiently, achieving electrical safety without excessive complexity.
Solution Approach 2:
The heat exchanger serves multiple functions simultaneously: it cools the non-conductive medium, provides thermal coupling between circuits, and acts as a physical barrier preventing media mixing. This multi-functionality reduces the need for additional components, managing system complexity.
3Temperature
If cooling water flows through a circulation path to cool the inverter, then inverter temperature control is improved, but the risk of water entering the oil circulation path and causing short circuits increases
Solution Approach 1:
The circulation system is segmented into distinct water and oil pathways with no direct connection points. The heat exchanger creates isolated zones where water and oil exchange heat but cannot mix, eliminating the risk of water contamination in the oil system while maintaining effective inverter cooling.
Solution Approach 2:
The heat exchanger serves as an intermediary that enables thermal interaction between the water cooling system and oil temperature control system without allowing fluid mixing. This mediator ensures the inverter is effectively cooled by water while the electric motor remains protected from water contamination.
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 effectively prevents short circuits by isolating conductive media within the temperature-control circuit, maintaining efficient temperature management and electrical safety.
Implementation Method 1
a heat exchanger configured to exchange heat between the first temperature-control medium and the second temperature-control medium
Implementation Method 2
a dropping pipe that is disposed inside the electric machine housing and above the first electric machine, extends in an axial direction of the first electric machine, and from which the first temperature-control medium drops onto the first electric machine
Data Source
AI summary
A vehicle drive device includes: a first electric machine; an electric machine housing accommodating the first electric machine; a live part that is provided inside the electric machine housing and is electrically connected to the first electric machine; and a temperature-control circuit for temperature control for the first electric machine. The temperature-control circuit includes: a first temperature-control circuit through which a non-conductive first temperature-control medium circulates; a second temperature-control circuit through which a conductive second temperature-control medium circulates; and a heat exchanger configured to exchange heat between the first temperature-control medium and the second temperature-control medium. A protection cover including a first protection wall is provided inside the electric machine housing.