Battery Case Cross Member Structure for Collision Rigidity

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Solution Overview

Problem

Existing battery case designs face challenges in achieving sufficient rigidity and strength without significant increases in weight and manufacturing cost, and often suffer from deformation and poor load-bearing performance during collisions.

Innovation Solution

A battery case design featuring a main body with a bottomed frame, reinforced by an inner cross member and side frame made of steel, which includes specific cross-sectional shapes and configurations to enhance rigidity and strength, while maintaining lightweight and cost-effective construction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a frame-shaped frame is disposed to surround the entire periphery of the tray, then strength is ensured, but the area in which the battery can be housed is limited and weight increases

Engineering Contradiction:
ImprovestrengthVSAvoidbattery housing area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

The invention extracts the frame from the battery housing area by positioning it outside the tray, allowing the battery to be housed in the tray without obstruction while the frame provides protective strength during collisions

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The frame is segmented into multiple members (front frame member, rear frame member, and side frame members) that are positioned at specific locations around the tray, providing strength where needed while minimizing interference with battery housing area

Inventive Principle:
Principle #1Segmentation

2Strength

If the frame is made of metal, then strength is ensured, but weight increases and energy efficiency decreases

Engineering Contradiction:
ImprovestrengthVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The frame members are designed with specific cross-sectional shapes (e.g., U-shaped, C-shaped, or I-shaped sections) that provide high strength-to-weight ratio, ensuring adequate protection while minimizing weight increase

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The frame members utilize three-dimensional cross-sectional geometries that provide structural strength through shape rather than mass, reducing weight while maintaining protective capability

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

3Strength

If the tray main body is made of metal, then deformation can be prevented, but weight increases significantly

Engineering Contradiction:
Improvedeformation resistanceVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The structure is divided into a tray main body and a separate frame, allowing the tray to be made of lighter material while the frame provides the necessary strength and deformation resistance

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery case uses a composite structure combining the tray main body with a metal frame, achieving both weight reduction and adequate strength through material differentiation

Inventive Principle:
Principle #40Composite materials

4Weight of moving object

If resin is used for the tray main body to reduce weight, then weight is reduced, but strength is low and deformation prevention requires increased thickness or reinforcement

Engineering Contradiction:
ImproveweightVSAvoidstrength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The structure separates the lightweight tray main body from the strength-providing frame, allowing resin to be used for the tray while metal frame members provide the necessary reinforcement without increasing tray thickness

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The battery case employs a composite construction with a resin tray main body and metal frame members, achieving weight reduction while maintaining adequate strength through the combination of materials

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP4685960A1Battery case
Publication Date: 2026.01.28 JFE STEEL CORP
  • EP4685960A1 patent drawingFigure 1
  • EP4685960A1 patent drawingFigure 2
  • EP4685960A1 patent drawingFigure 3~4

AI summary

A battery case 1 of the present invention includes an inner cross member 3 extending in the vehicle width direction extend over a pair of side wall portions 12 and 13 in a main body 2. The inner cross member 3 includes a top plate section, a pair of vertical wall portions, and a pair of flange sections, the pair of vertical wall portions includes a front side vertical wall portion and a rear side vertical wall portion facing each other in the vehicle front-rear direction, and a ridgeline portion extending in the vehicle width direction is formed in at least one of the front vertical wall and the rear vertical wall.