Secondary Battery Tab Structure for Weld Zone Isolation

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Solution Overview

Problem

Secondary batteries face performance issues due to weld zones causing damage to the electrode assembly during assembly and operation, and existing isolating plates have poor stability and complex installation processes.

Innovation Solution

A secondary battery design featuring a cap plate with electrode terminals, electrode tabs, and connecting pieces, where insulating adhesives cover weld zones and are securely adhered to prevent damage, combined with welding protecting pieces for enhanced stability and safety, and optimized bending angles to minimize space usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If an isolating plate is provided between the weld zones and the electrode assembly, then the weld zones are isolated from the electrode assembly, but the isolating plate shakes easily during working process and has poor stability

Engineering Contradiction:
Improveweld zones damaging electrode assemblyVSAvoidstability of isolating plate
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a bending portion as an intermediary element between the weld zone and the electrode assembly main body. This bending portion acts as a mediator that absorbs mechanical stress and prevents direct contact between the rigid weld zone and the electrode assembly, thereby eliminating the shaking problem of traditional isolating plates while maintaining effective isolation.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The electrode tab is segmented into multiple functional portions: a connecting portion for welding, a bending portion for isolation and stress absorption, and other structural portions. This segmentation allows each part to perform its specific function optimally, with the bending portion specifically designed to prevent damage to the electrode assembly while maintaining stability.

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If an isolating plate is provided between the weld zones and the electrode assembly, then the weld zones are isolated from the electrode assembly, but the installing process becomes complex

Engineering Contradiction:
Improveweld zones damaging electrode assemblyVSAvoidcomplexity of installing process
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the isolating function with the electrode tab structure itself by adding a bending portion to the electrode tab. This integration eliminates the need for separate isolating plates and their complex installation processes, while still achieving effective isolation between weld zones and the electrode assembly main body.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The electrode tab's bending portion serves dual purposes: it provides structural connection and simultaneously performs the isolating function. The structure is self-sufficient, eliminating the need for additional isolating components and simplifying the overall assembly process.

Inventive Principle:
Principle #25Self-service

3Object-affected harmful factors

If insulating adhesive is used to cover weld zones, then the weld zones are isolated from the electrode assembly, but the thickness of insulating material increases

Engineering Contradiction:
Improveweld zones damaging electrode assemblyVSAvoidthickness of insulating adhesive
Core Design Contradiction:
Object-affected harmful factorsVSVolume of moving object

Solution Approach 1:

The patent employs a thin film approach by using a bending portion with minimal thickness to achieve effective isolation. This thin film structure provides sufficient insulating and protective functionality while occupying minimal space, thereby avoiding the volume increase associated with thicker insulating materials.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The bending portion is designed with specific local geometric characteristics (curvature radius, thickness, and shape) that are optimized for the isolation function at the specific location of the weld zone. This localized design provides effective protection with minimal material usage, avoiding the need for thick uniform insulation throughout.

Inventive Principle:
Principle #3Local quality

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

The solution improves safety performance by isolating weld zones, simplifies the assembly process, enhances stability, and increases energy density by preventing short circuits and reducing the thickness of insulating materials.

Implementation Method 1

a first insulating adhesive adhered on weld zones which are formed during welding of the first connecting portion and the first connecting piece and face the main body of the electrode assembly

Methodology Applied
Scientific EffectAdhesion: Adhesive

Implementation Method 2

The first welding protecting piece, the first connecting portion and the first connecting piece are securely connected together by ultrasonic welding

Methodology Applied
Scientific EffectUltrasonic welding: Ultrasonic Vibration

Data Source

PatentEP3331062B1Secondary battery
Publication Date: 2024.05.29 CONTEMPORARY AMPEREX TECHNOLOGY (HONG KONG) LIMITED
  • EP3331062B1 patent drawingFigure 1
  • EP3331062B1 patent drawingFigure 2~3
  • EP3331062B1 patent drawingFigure 4~5

AI summary

The present invention provides a secondary battery which comprises: a cap plate provided with a first electrode terminal and a second electrode terminal; an electrode assembly comprising a main body, a first electrode tab provided to the main body and a second electrode tab provided to the main body; a first connecting piece connected between the first electrode tab and the first electrode terminal. The second electrode tab is connected with the second electrode terminal. The first electrode tab includes a first connecting portion welded with the first connecting piece and a first bending portion bent downwardly and connected between the main body of the electrode assembly and the first connecting portion. A first insulating adhesive is adhered on weld zones which are formed during welding of the first connecting portion and the first connecting piece and face the main body of the electrode assembly.