Wound Battery Cell Tab Ring Layout for Flat Collector Welding

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Solution Overview

Problem

Existing lithium-ion battery technologies suffer from inconsistent tab layer thickness and poor flatness due to overlapping and stacking issues, leading to inefficiencies in welding and manufacturing yield.

Innovation Solution

The tab ring of an outer electrode ring covers the tab ring of an inner electrode ring, with isosceles trapezoidal tabs and controlled included angles, ensuring a flat tab plane without holes or uneven thickness, enhancing welding yield and foil utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of tab rings is increased to improve energy density, then the energy density of the lithium-ion battery is significantly increased, but the number of tab layers stacked on inner and outer rings becomes inconsistent, causing poor flatness of the entire flattened plane of the tabs

Engineering Contradiction:
Improveenergy densityVSAvoidflatness of tab plane
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The patent implements a nested arrangement where outer tab rings are positioned to cover inner tab rings in the radial direction. This nesting configuration ensures that tabs from multiple rings align properly when flattened, creating a uniform thickness profile across the entire tab plane while accommodating an increased number of tab rings for higher energy density

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent applies different positioning strategies to different tab rings based on their radial positions. Outer tab rings are specifically designed to cover inner tab rings, creating localized overlapping regions that ensure uniform thickness distribution across the flattened tab plane, rather than applying a uniform arrangement to all rings

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If tabs are flattened after winding to improve assembly, then partially overlapped regions exist at positions on both sides, resulting in stacking of tabs with inconsistent thickness and poor flatness

Engineering Contradiction:
Improveassembly convenienceVSAvoiduniformity of tab thickness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent performs preliminary positioning of tabs during the winding process, ensuring that tabs from outer rings are pre-aligned to cover tabs from inner rings. This preliminary action prevents the formation of overlapped regions and stacking issues that would otherwise occur after flattening, maintaining uniform thickness throughout the tab plane

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4683097A1Battery cell and battery
Publication Date: 2026.01.21 BYD CO LTD
  • EP4683097A1 patent drawingFigure 1~2
  • EP4683097A1 patent drawingFigure 3~4
  • EP4683097A1 patent drawing

AI summary

Disclosed is a battery. The battery includes a battery cell. The battery cell includes: positive electrode sheets, negative electrode sheets and separators. The positive electrode sheets, the negative electrode sheets and the separators are mutually stacked, the battery cell is formed by winding the positive electrode sheets, the separators and the negative electrode sheets, and the positive electrode sheets, the negative electrode sheets and the separators form a plurality of electrode rings in a radial direction. The positive electrode sheets and the negative electrode sheets each include a sheet body, a bare foil region and a plurality of tabs. The bare foil region is arranged on one side of the sheet body in a height direction, and the plurality of tabs are spaced apart on one side of the bare foil region facing away from the sheet body. A tab ring of an outer one of the electrode rings covers a tab ring of an inner one of the electrode rings. A relatively complete plane is obtained after the tabs of each ring are flattened, thereby forming a flat tab plane internally having no hole caused by stacking of the tabs or an uneven thickness of the tabs.