Wound Electrode Assembly Flags for Better Battery Tab Welding

Solution Overview

Problem

Existing secondary batteries face challenges in improving welding quality and minimizing height differences due to bending of uncoated portions, which affect performance.

Innovation Solution

The electrode assembly design includes a first electrode with a coated portion and an uncoated portion featuring cut portions and flags, where the length of cut portions increases in radial directions, and the uncoated portion is structured to minimize height differences and facilitate even welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the uncoated portion is made longer to facilitate electrode assembly, then the ease of manufacture is improved, but the height difference due to bending increases, worsening the welding quality

Engineering Contradiction:

Improveease of electrode assemblyVSAvoidwelding quality

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The uncoated portion is divided into multiple segments by forming cut portions that extend from the end toward the coated portion. This segmentation creates multiple flags that can bend independently, reducing the height difference at the tip while maintaining the overall length for easy assembly. The cut portions are arranged in multiple rows with different lengths, allowing progressive bending control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the uncoated portion are given different properties through varying cut portion lengths. The cut portions are arranged in multiple rows where inner row cut portions are shorter and outer row cut portions are longer, creating local variations in bending characteristics. This allows the tip region to have reduced height difference while maintaining overall flexibility for assembly.

Inventive Principle:

Principle #3Local quality

2Manufacturing precision

If additional welding steps are added to improve welding quality, then the manufacturing precision is improved, but the device complexity and manufacturing time increase

Engineering Contradiction:

Improvewelding qualityVSAvoidnumber of welding steps

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The electrode structure is pre-configured with cut portions and flags that automatically reduce height difference during assembly. This preliminary structural design eliminates the need for additional welding steps to correct height differences, as the flags are designed to naturally align and minimize gaps before welding occurs.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The uncoated portion with cut portions serves a dual function: it facilitates electrode assembly through its flexibility while simultaneously reducing height difference through its bending characteristics. The structure is self-adjusting, requiring no additional corrective welding steps.

Inventive Principle:

Principle #25Self-service

3Ease of operation

If the uncoated portion is made longer to facilitate assembly, then the ease of manufacture is improved, but the height difference due to bending increases, worsening the welding quality

Engineering Contradiction:

Improveease of assemblyVSAvoidconnection performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The uncoated portion is divided into multiple segments by forming cut portions that extend from the end toward the coated portion. This segmentation creates multiple flags that can bend independently, reducing the height difference at the tip while maintaining the overall length for easy assembly. The cut portions are arranged in multiple rows with different lengths, allowing progressive bending control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the uncoated portion are given different properties through varying cut portion lengths. The cut portions are arranged in multiple rows where inner row cut portions are shorter and outer row cut portions are longer, creating local variations in bending characteristics. This allows the tip region to have reduced height difference while maintaining overall flexibility for assembly.

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20260066330A1Electrode Assembly and Battery Cell Including the Same

Publication Date: 2026.03.05 SK ON CO LTD

AI summary

An electrode assembly includes a first electrode, a second electrode, and a separator located between the first electrode and the second electrode. The first electrode, the second electrode, and the separator are wound in a roll shape. The first electrode includes a first coated portion in which a first active material is coated on a first current collector, and a first uncoated portion adjacent to the first coated portion and formed at one side of the first current collector. The first uncoated portion includes a plurality of cut portions each open to an outside and a plurality of flags partitioned by the plurality of cut portions. A length of each of the plurality of cut portions increases in at least one or more sections in a radial direction from a winding center.