EV Front Body Structure With Rearward Motor Crash Load Path

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Solution Overview

Problem

In electric vehicles, the absence of an engine and reduced accessory components leads to insufficient absorption of impact loads during collisions, posing a risk of impact loads being exerted on batteries due to the proximity of the traveling motor to the batteries.

Innovation Solution

A vehicle-body front structure with a partition wall portion bulging into the cabin to house the traveling motor and a reinforcement member extending rearward, connected to a battery unit, dispersing impact loads through a rack frame and cross members, and fastening the reinforcement member to the floor panel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If the traveling motor is disposed close to the vehicle rear side, then the crash stroke is sufficiently secured, but the traveling motor approaches the batteries and may exert impact load on the battery during collision

Engineering Contradiction:
Improvecrash strokeVSAvoidimpact load on battery
Core Design Contradiction:
Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a reinforcement member as an intermediary component between the traveling motor and the battery unit. This reinforcement member absorbs and disperses the impact load during collision, preventing the force from being directly transmitted to the battery while allowing the motor to be positioned close to the rear for adequate crash stroke.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent creates a motor arrangement portion that bulges into the vehicle cabin from the partition wall, utilizing the vertical and lateral dimensions to position the motor closer to the rear while maintaining spatial separation from the battery unit through the partition wall structure.

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

2Device complexity

If accessory components are largely decreased in electric vehicles compared to engine vehicles, then the vehicle structure is simplified, but the impact load cannot be sufficiently absorbed during collision

Engineering Contradiction:
Improvevehicle structureVSAvoidimpact load absorption
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The patent segments the partition wall structure by creating a motor arrangement portion that bulges into the cabin, and separately introduces a reinforcement member extending to the battery unit. This segmentation allows the structure to maintain simplicity while providing dedicated zones for motor placement and impact load management.

Inventive Principle:
Principle #1Segmentation

3Length of moving object

If the partition wall portion is made to bulge into the vehicle cabin to create motor arrangement space, then the traveling motor can be positioned rearward, but the structural integrity of the partition wall may be compromised

Engineering Contradiction:
Improvemotor positionVSAvoidpartition wall integrity
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The reinforcement member is pre-installed extending from the motor arrangement portion to the battery unit before collision occurs. This preliminary structural reinforcement ensures that when impact occurs, the force is immediately directed along the reinforcement member's path to the battery unit, preventing structural compromise of the partition wall during the actual collision event.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4234300B1Vehicle-body front structure
Publication Date: 2025.11.05 MAZDA MOTOR CORP
  • EP4234300B1 patent drawingFigure 1
  • EP4234300B1 patent drawingFigure 2
  • EP4234300B1 patent drawingFigure 3

AI summary

[Problem] In an electric vehicle, a traveling motor is disposed as close to a vehicle rear side as possible, and an impact load is thereby inhibited from being exerted on a battery in a collision while a crash stroke in the collision is sufficiently secured in a front-rear direction. [Means for Solution] A vehicle-body front structure A includes a partition wall portion which is provided to extend in a vehicle width direction in a vehicle front portion, a motor arrangement portion 71a which is formed by causing a part of the partition wall portion to bulge to an inside of a vehicle cabin and in which at least a part of a traveling motor M1 is capable of being arranged, and a reinforcement member 94 which extends from the motor arrangement portion 71a to vehicle rear. A rear portion of the reinforcement member 94 is mounted on a inside-unit member 25A which is provided in the battery unit BY.