Transferable Electrode Tip for Robust Anode Tab Resistance Welding

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Solution Overview

Problem

Existing resistance welding techniques face challenges in creating robust and consistent welds between dissimilar materials like nickel anode current collector tabs and stainless-steel casings, often resulting in sticking issues and damage during the welding process, especially when welding multiple tabs together.

Innovation Solution

The introduction of a high resistance transferable electrode tip between the welding electrode and the anode tabs helps to concentrate heat and create point-welds, ensuring a robust connection by maintaining a resistive balance and preventing copper contamination on the anode tabs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If copper welding electrodes are used for resistance welding nickel anode tabs to stainless-steel casings, then the welding process is simple and effective, but copper softening causes the electrode to stick to the anode tab and copper contamination is left behind

Engineering Contradiction:
Improvewelding process simplicityVSAvoidcopper contamination and electrode sticking
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

A transferable electrode tip made of high-resistivity material (such as nickel or stainless steel) is introduced as an intermediary between the copper welding electrode and the nickel anode tab. This tip concentrates the heat at the weld point and prevents copper from directly contacting and contaminating the anode tab, while still enabling effective resistance welding of the dissimilar materials.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If resistance welding is used to join dissimilar materials with different thicknesses (thin anode tabs and thick casings), then the joining process is efficient, but the thin tabs are prone to tearing when the electrode is withdrawn

Engineering Contradiction:
Improvewelding efficiencyVSAvoidtab integrity during electrode withdrawal
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The transferable electrode tip creates a localized high-resistance zone at the weld point, concentrating heat generation precisely where needed. This allows the welding energy to be focused on creating a strong bond between the thin tab and thick casing without overheating or weakening the tab material, preventing tab tearing during electrode withdrawal.

Inventive Principle:
Principle #3Local quality

3Reliability

If multiple anode tabs are stacked and welded together, then the electrical connection is improved, but the tabs do not weld robustly to each other and pull tests are required to verify connection strength

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidwelding robustness and verification time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The transferable electrode tip acts as a mediator that distributes heat evenly across the stacked tab interfaces, ensuring consistent welding between multiple tabs. The high-resistivity material maintains thermal concentration at each weld point, creating robust bonds between tabs without requiring pull tests for verification.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 results in consistent and robust welds between the anode tabs and the cell casing, reducing the risk of tab damage and copper contamination, while allowing for reliable connections even when multiple tabs are stacked and welded.

Implementation Method 1

a high resistance transferable electrode tip between the welding electrode and the anode tabs helps to concentrate heat and create point-welds

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Data Source

PatentEP3614461B1A transferable electrode tip for resistance welding an anode tab to the casing of an electrochemical cell
Publication Date: 2023.11.15 GREATBATCH LTD
  • EP3614461B1 patent drawingFigure 1
  • EP3614461B1 patent drawingFigure 2
  • EP3614461B1 patent drawingFigure 3

AI summary

A new weld configuration is used to obtain a robust and consistent resistance weld between the tabs of an anode current collector and the casing of an electrochemical cell. This is done by adding a resistive transferable electrode tip between at least one of the welding electrodes, preferably the movable welding electrode, and the stacked parts that are being joined together. The purpose of the transferable electrode tip is to generate a sufficient amount of heat during the welding process so that the stacked parts are joined together without adding any product functionality. In one embodiment of the present invention, the transferrable electrode tip is a stainless-steel ball, the stacked anode current collector tabs are of nickel, and the cell casing is of stainless-steel.