Electric Vehicle High Voltage Unit Mount Structure

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Solution Overview

Problem

High voltage units in electric vehicles, when arranged vertically, experience increased moment of inertia during collisions, leading to higher impact loads and a higher likelihood of breakage due to their barycenter being farther from the vehicle body fixing point.

Innovation Solution

The solution involves arranging a first high voltage unit with vehicle body fixing parts at both ends in the width direction and a second high voltage unit above it vertically, with heavy components in the second unit positioned closer to the lowermost surface, reducing the distance between the barycenter and the vehicle body fixing point, thereby lowering the moment of inertia and impact load.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the inverter case and motor case are arranged in the vertical direction to secure space in the motor room, then the space utilization is improved, but the moment of inertia increases and impact load during collision becomes greater

Engineering Contradiction:
Improvespace utilizationVSAvoidimpact resistance
Core Design Contradiction:
Volume of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by strategically positioning heavy components (inverter case, capacitor, cooling fan) at the lower portion of the vertical arrangement. This creates a non-uniform mass distribution where the lower section has higher density, thereby lowering the barycenter and reducing moment of inertia during collision while maintaining the vertical space-efficient configuration.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the vehicle body fixing part is provided on the motor case to fix the electromechanical integrated unit, then the mounting simplicity is improved, but the distance between the fixing part and barycenter increases, leading to greater moment of inertia

Engineering Contradiction:
Improvemounting simplicityVSAvoidcollision resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent uses the motor case as a counterweight structure. By positioning the heavy inverter case and other high-voltage components on the upper side of the motor case (which serves as the base), the system creates a counterbalancing effect where the motor case's mass helps stabilize the overall structure during collision, reducing the effective moment of inertia around the vehicle body fixing part.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Data Source

PatentEP2899046B1Power electric unit mount structure for electric vehicle
Publication Date: 2018.02.21 NISSAN MOTOR CO LTD
  • EP2899046B1 patent drawingFigure 1A~1B
  • EP2899046B1 patent drawingFigure 2A~2B
  • EP2899046B1 patent drawingFigure 3A~3C

AI summary

A mounting structure of a high voltage unit for an electric vehicle includes a first high voltage unit that has vehicle body fixing parts to be fixed to a vehicle body at both ends in a width direction, and a second high voltage unit that is arranged on an upper side of the first high voltage unit in a vertical direction of the vehicle, in which, in the second high voltage unit, a high voltage heavy component included in the second high voltage unit is arranged closer to a lowermost surface in the vertical direction of the vehicle.