Rectangular Battery Can Tubular Structure With Tight Thickness Tolerance

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Solution Overview

Problem

Conventional methods for manufacturing rectangular battery cans for electric vehicles face challenges in achieving high dimensional accuracy and uniform thickness, leading to issues with electrolyte charging capacity and increased process complexity, resulting in defects and high costs.

Innovation Solution

A method involving hot-extrusion of aluminum alloy materials at high temperatures with a pressure of 200 bar or more, followed by skin pass drawing using a drawing mold with a plug mold curvature greater than or equal to the die mold curvature, to achieve a thickness tolerance of ±0.07 mm or less, reducing the number of manufacturing processes and enhancing productivity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If conventional extrusion methods are used to manufacture rectangular battery cans, then manufacturing simplicity is maintained, but thickness uniformity and dimensional accuracy deteriorate (tolerance ±0.15 mm)

Engineering Contradiction:
Improvethickness uniformityVSAvoidprocess complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by modifying the extrusion temperature to a specific range (400-500°C) and controlling extrusion speed (0.5-2.0 mm/s) to achieve uniform thickness and high dimensional accuracy (±0.07 mm or less) while maintaining process simplicity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The manufacturing process is segmented into specific controlled stages: heating the extruded material to a predetermined temperature range, then extruding at a controlled speed. This segmentation allows precise control over thickness uniformity without increasing overall process complexity

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If thicker battery can walls are used to ensure dimensional accuracy, then manufacturing precision improves, but the volume available for electrolyte decreases

Engineering Contradiction:
Improvedimensional accuracyVSAvoidelectrolyte capacity
Core Design Contradiction:
Manufacturing precisionVSQuantity of substance

Solution Approach 1:

The patent uses hydraulic pressure control during extrusion (200-500 bar) to achieve precise dimensional control with thin walls, allowing maximum electrolyte volume while maintaining the required thickness uniformity of ±0.07 mm or less

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Manufacturing precision

If multiple manufacturing processes are used to achieve high precision, then manufacturing precision improves, but productivity decreases and costs increase

Engineering Contradiction:
Improvethickness toleranceVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent combines heating and extrusion operations into a single integrated process step, where the extruded material is heated to a predetermined temperature and extruded at a controlled speed in one continuous operation. This merging achieves ±0.07 mm thickness tolerance while improving productivity by eliminating separate processing steps

Inventive Principle:
Principle #5Merging (Combining)

4Manufacturing precision

If conventional extrusion pressure is used, then energy consumption is reduced, but thickness uniformity deteriorates

Engineering Contradiction:
Improvethickness uniformityVSAvoidextrusion energy
Core Design Contradiction:
Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent optimizes extrusion pressure to a specific range (200-500 bar) combined with controlled extrusion speed (0.5-2.0 mm/s) to achieve uniform thickness distribution. This parameter optimization ensures adequate material flow control for precision while avoiding excessive energy consumption

Inventive Principle:
Principle #35Parameter changes

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

This approach enables the production of thin, high-accuracy tubular structures that can contain more electrolyte within a limited size, reducing material loss, process failures, and manufacturing costs while minimizing defects and the need for additional welding processes.

Implementation Method 1

hot-extrusion of aluminum alloy materials at high temperatures

Methodology Applied
Scientific EffectThermal energy input: Heating

Implementation Method 2

hot-extruding a material prepared using the aluminum alloy at a high temperature such that the extruded material has a rectangular cross-section while having a thickness tolerance of ±0.07 to 0.10 mm

Methodology Applied
Scientific EffectPressure application: Pressure Increase

Implementation Method 3

drawing the hot-extruded material using a drawing mold such that the drawn material has a thickness tolerance of ±0.07 mm or less

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP4336628A1Tubular structure for rectangular battery can for electric vehicle and method of manufacturing the same
Publication Date: 2024.03.13 ALUTEC CO LTD
  • EP4336628A1 patent drawingFigure 1
  • EP4336628A1 patent drawingFigure 2
  • EP4336628A1 patent drawingFigure 3

AI summary

A tubular structure for a rectangular battery can for an electric vehicle, which is thin and has very high dimensional accuracy in order to contain as much electrolyte as possible within a limited size, and a method of manufacturing the same are disclosed. In particular, extrusion of a material to a predetermined thickness is performed, and drawing of the extruded material to a thickness desired by a final product is performed. Accordingly, desired thickness uniformity of the final product is maintained.