Electric Vehicle Underbody with Segmented Battery Mounting

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Solution Overview

Problem

Electric vehicles face limitations in travel range due to heavy underbody structures, which compromise strength and increase maintenance costs, and existing solutions either reduce underbody strength or incur high environmental impact.

Innovation Solution

A lightweight underbody design with a multiply divided battery mounting portion and reinforcing underbody structure, featuring upper and lower floor members with cross members, allowing selective battery mounting and replacement, and incorporating shaped steel members for strength and reduced weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the underbody material is replaced with plastic or aluminum to reduce weight, then the underbody weight is reduced, but the CO2 discharge increases, recycling difficulty increases, strength maintenance becomes difficult, and cost increases

Engineering Contradiction:
Improveunderbody weightVSAvoidCO2 discharge
Core Design Contradiction:
Weight of moving objectVSObject-generated harmful factors

Solution Approach 1:

The underbody is divided into multiple components: steel floor members (12, 14) for structural integrity, floor cross members (16) for additional support, and battery packs (B) as removable modules. This segmentation allows the use of steel materials that are recyclable and have lower CO2 discharge compared to plastic or aluminum alternatives, while still achieving weight reduction through optimized structure and removable battery packs.

Inventive Principle:
Principle #1Segmentation

2Weight of moving object

If portions of the steel underbody are made high-strength to reduce material thickness, then the underbody weight is reduced, but the overall underbody strength against bending and twisting deteriorates

Engineering Contradiction:
Improveunderbody weightVSAvoidunderbody strength against bending and twisting
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The underbody structure is segmented into floor members (12, 14) and floor cross members (16) that work together as a composite framework. This segmentation allows the use of standard-strength steel materials throughout while maintaining overall structural strength through the distributed framework design, avoiding the need for high-strength materials that would compromise recyclability and increase cost.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The underbody employs a composite structure combining floor members and floor cross members made of steel materials. This composite framework approach allows the use of conventional steel with good recyclability and lower CO2 discharge, while the combined structure provides sufficient strength against bending and twisting without requiring high-strength alloys.

Inventive Principle:
Principle #40Composite materials

3Ease of operation

If the battery mounting structure is simplified to enable easy replacement, then the ease of operation is improved, but the underbody strength may be compromised

Engineering Contradiction:
Improvebattery replacement easeVSAvoidunderbody strength
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The battery mounting system is segmented into removable battery packs (B) that can be independently mounted and removed from the underbody. The battery packs are designed as separate modules that interface with the floor members and cross members through standardized mounting points, allowing easy replacement without requiring complex tools or procedures, while the distributed mounting points maintain structural integrity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The floor members (12, 14) and floor cross members (16) serve multiple functions: they provide structural support for the underbody, serve as mounting structures for battery packs, and maintain overall vehicle strength. This multi-functionality allows the same structural components to enable easy battery replacement while preserving underbody strength against bending and twisting.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2658768B1Underbody for electric vehicle
Publication Date: 2017.09.27 POHANG IRON & STEEL CO LTD
  • EP2658768B1 patent drawingFigure 1
  • EP2658768B1 patent drawingFigure 2
  • EP2658768B1 patent drawingFigure 3

AI summary

An underbody for an electric vehicle configured as an electric vehicle lower body includes a multiply divided battery mounting portion and an underbody portion. The multiply divided battery mounting portion enables multiply divided and selective mounting of batteries, and forms a portion of the underbody. The underbody portion is connected to the battery mounting portion and forms another portion of the underbody.