Wound Battery Tab Layout to Prevent Separator Burning

Solution Overview

Problem

Current secondary batteries face challenges in balancing the number of stacked layers of positive and negative electrode tabs during welding, which can lead to separator burning or reduced energy density.

Innovation Solution

The design includes a wound structure where the number of turns of the positive electrode tab stack layer number stable region exceeds that of the negative electrode tab stack layer number stable region, ensuring sufficient unwelded tab layers while minimizing the negative electrode tab layers to prevent separator burning and maintain energy density.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of stacked layers of positive electrode tab is increased to prevent separator burning during welding, then the reliability of welding process is improved, but the energy density of the battery decreases due to excessive tab layers occupying active material space

Engineering Contradiction:

Improvewelding process reliabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies asymmetry by intentionally creating an unequal number of stacked tab layers between positive and negative electrodes. Specifically, the positive electrode tab stack layer number stable region is designed to have more layers than the negative electrode tab stack layer number stable region. This asymmetric design ensures sufficient unwelded tab layers are reserved in both regions to prevent separator burning during welding, while minimizing the negative electrode tab layers to maintain high energy density.

Inventive Principle:

Principle #4Asymmetry

2Reliability

If the number of stacked layers of negative electrode tab is increased to ensure sufficient unwelded tab layers, then the reliability of welding process is improved, but the energy density of the battery decreases due to excessive tab layers

Engineering Contradiction:

Improvewelding process reliabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent applies asymmetry by intentionally creating an unequal number of stacked tab layers between positive and negative electrodes. Specifically, the positive electrode tab stack layer number stable region is designed to have more layers than the negative electrode tab stack layer number stable region. This asymmetric design ensures sufficient unwelded tab layers are reserved in both regions to prevent separator burning during welding, while minimizing the negative electrode tab layers to maintain high energy density.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent applies parameter changes by optimizing the specific number of stacked tab layers in each region. The positive electrode tab stack layer number stable region is designed with a greater number of layers compared to the negative electrode tab stack layer number stable region. This parameter optimization ensures that both regions have sufficient unwelded tab layers to prevent separator burning during welding, while the negative electrode tab layers are minimized to maintain high energy density.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If equal number of turns are provided for both positive and negative electrode tabs, then the manufacturing simplicity is maintained, but the separator may be burned during welding due to insufficient unwelded tab layers

Engineering Contradiction:

Improvemanufacturing simplicityVSAvoidwelding process reliability

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by intentionally creating an unequal number of stacked tab layers between positive and negative electrodes. Specifically, the positive electrode tab stack layer number stable region is designed to have more layers than the negative electrode tab stack layer number stable region. This asymmetric design ensures sufficient unwelded tab layers are reserved in both regions to prevent separator burning during welding.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The patent applies parameter changes by optimizing the specific number of stacked tab layers in each region. The positive electrode tab stack layer number stable region is designed with a greater number of layers compared to the negative electrode tab stack layer number stable region. This parameter optimization ensures that both regions have sufficient unwelded tab layers to prevent separator burning during welding.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20260088465A1Secondary battery, battery assembly, and electronic device

Publication Date: 2026.03.26 AESC JAPAN LTD

AI summary

A secondary battery, a battery assembly, and an electronic device are provided. The secondary battery includes: a housing and an electrode assembly accommodated in the housing. The electrode assembly includes a wound structure formed by stacking and winding a positive electrode sheet, a separator, and a negative electrode sheet. Along an axial direction of the wound structure, a positive electrode current collector of the positive electrode sheet includes a positive electrode coated region and a positive electrode uncoated region. A negative electrode current collector of the negative electrode sheet includes a negative electrode coated region and a negative electrode uncoated region. A part of the positive electrode uncoated region is bent to form a stacked positive electrode tab region. A part of the negative electrode uncoated region is bent to form a stacked negative electrode tab region.