Press-Hardened Battery Tray Geometry for Space and Crashworthiness

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Solution Overview

Problem

Existing battery trays for electric vehicles are not optimized for simplified manufacturing, internal receiving space, and crashworthiness, particularly in terms of crash performance and structural integrity.

Innovation Solution

A hot-formed and press-hardened battery tray made from a sheet steel blank, with angled side walls and outwardly shaped corners, optimized for manufacturing efficiency and crash performance, incorporating reinforcing structures and cooling channels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the side walls are made vertical to maximize internal space, then the available installation space for batteries is improved, but the manufacturability in deep-drawing or press-forming process deteriorates due to high forming difficulty

Engineering Contradiction:
Improveinternal receiving spaceVSAvoidmanufacturability
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The side walls are designed with a specific inclination angle (greater than 1° from vertical) rather than being perfectly vertical. This parameter modification resolves the contradiction by making the forming process feasible while maintaining adequate internal space for battery installation.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If the side walls are made less steep (greater angle to vertical) to improve manufacturability, then the ease of manufacture is improved, but the crash characteristics in frontal and side impacts deteriorate

Engineering Contradiction:
ImprovemanufacturabilityVSAvoidcrash characteristics
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The side walls are designed with a specific inclination angle (greater than 1° from vertical) rather than being perfectly vertical. This parameter modification resolves the contradiction by making the forming process feasible while maintaining adequate internal space for battery installation.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If the corner areas are designed with high stretching to achieve compact shape, then the volume efficiency is improved, but the manufacturing process deteriorates due to risk of breakage or tearing

Engineering Contradiction:
Improvevolume efficiencyVSAvoidmanufacturing process
Core Design Contradiction:
Volume of moving objectVSEase of manufacture

Solution Approach 1:

The corner areas are designed with outward offset and curved surfaces instead of sharp angles. This curvature reduces stress concentration and stretching during forming, preventing breakage or tearing while maintaining compact volume efficiency.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Strength

If the battery tray is designed with complex reinforcing structures to improve crashworthiness, then the strength is improved, but the device complexity increases

Engineering Contradiction:
ImprovecrashworthinessVSAvoidstructural complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The reinforcing structures are integrated into the battery tray itself rather than being separate components. This merging approach improves crashworthiness through inherent structural reinforcement while avoiding the complexity of additional parts and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances manufacturing simplicity, improves crashworthiness, optimizes internal space for batteries and electrical connections, and reduces material and weight through efficient structural design.

Implementation Method 1

For hot forming, the blank is first heated to above the austenitizing temperature, i.e., above 900°C, then hot-formed in a press, and subsequently cooled or quenched and hardened.

Methodology Applied
Scientific EffectHot forming: Heating

Implementation Method 2

For hot forming, the blank is first heated to above the austenitizing temperature, i.e., above 900°C, then hot-formed in a press, and subsequently cooled or quenched and hardened.

Methodology Applied
Scientific EffectQuenching and hardening: Cooling

Data Source

PatentEP4631754B1Thermoformed and press-hardened battery tray
Publication Date: 2026.01.21 BENTELER AUTOMOBILTECHNIK GMBH
  • EP4631754B1 patent drawingFigure 1
  • EP4631754B1 patent drawingFigure 2
  • EP4631754B1 patent drawingFigure 3

AI summary

The present invention relates to a battery tray (1) for an electric vehicle, produced as a hot-formed and press-hardened component from a sheet steel blank, comprising a base (2) and side walls (5, 6) rising from the base (2) with a flange (7) running around the top of the battery tray (1) and projecting outwards, characterized in that the side walls (5) on the long sides of the battery tray (1) and the side walls (6) on the transverse sides are oriented at an angle (β) greater than 1° to a vertical, wherein in a respective corner region (8) the base (2) of the battery tray (2) merges into a curved surface (9) in such a way that a transition radius (14) of the curved surface (9) to a transverse side wall (6) results, and a transition radius (11) of the curved surface (9) to a long side wall (11) results.