EV Power Unit Layout for Centered Weight Distribution

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Solution Overview

Problem

The weight distribution of heavy components such as the inverter in electric vehicles affects vehicle handling, necessitating optimal mounting positions to improve handling.

Innovation Solution

The electric vehicle is configured with front and rear motors, each integrated with a power control device, where the battery is positioned underneath and the power control devices are disposed closer to the center of gravity, with motors and drive shafts overlapping to minimize size and maximize space for the battery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the inverter is mounted on the upper surface of the transaxle case, then the device complexity is reduced, but the weight distribution deteriorates and vehicle handling worsens

Engineering Contradiction:
Improvemounting structure complexityVSAvoidweight distribution
Core Design Contradiction:
Device complexityVSStability of the object's composition

Solution Approach 1:

The inverter is relocated from a horizontal mounting position on the transaxle case to a vertical mounting position on the lower surface of the battery case. This dimensional change in mounting orientation allows the heavy inverter to be positioned lower in the vehicle, improving weight distribution and lowering the center of gravity while maintaining integration with the drive system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The battery case serves as an intermediary mounting structure for the inverter. Instead of mounting the inverter directly on the transaxle case, the battery case acts as a mediator that provides a mounting surface on its lower surface, enabling optimal weight distribution while maintaining system integration.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the battery is positioned underneath the floor between the drive wheels, then the weight distribution and handling are improved, but the space availability for other components is reduced

Engineering Contradiction:
Improveweight distributionVSAvoidavailable space
Core Design Contradiction:
Stability of the object's compositionVSArea of stationary object

Solution Approach 1:

The inverter is mounted on the lower surface of the battery case, utilizing the vertical dimension below the battery assembly. This allows the inverter to be positioned in the vertical space underneath the floor, alongside the battery, without requiring additional horizontal space that would conflict with the battery placement.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The inverter is nested within the vertical space defined by the battery case structure. By mounting the inverter on the lower surface of the battery case, the system effectively nests two heavy components (battery and inverter) within the same vertical envelope, maximizing space utilization.

Inventive Principle:
Principle #7Nested doll (Nesting)

Data Source

PatentEP4663442A1Electric vehicle
Publication Date: 2025.12.17 TOYOTA JIDOSHA KK
  • EP4663442A1 patent drawingFigure 1~2
  • EP4663442A1 patent drawingFigure 3~4
  • EP4663442A1 patent drawingFigure 5~6

AI summary

An electric vehicle (30) includes a first integrated electromechanical unit (37) including a first motor (35) and a first power control device (34), and a second integrated electromechanical unit (41) including a second motor (39) and a second power control device (38). The first integrated electromechanical unit (37) is configured to drive front wheels (31) via first drive shafts (36). The second integrated electromechanical unit (41) is configured to drive rear wheels (32) via second drive shafts (40). A battery (33) is disposed underneath a floor and between the front wheels (31) and the rear wheels (32). The first integrated electromechanical unit (37) is disposed forward of the battery (33). The second integrated electromechanical unit (41) is disposed rearward of the battery (33). The first power control device (34) is disposed rearward of the first motor (35). The second power control device (38) is disposed forward of the second motor (39).