Battery Cell Terminal Threaded Joint to Eliminate Weld Spatter

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Solution Overview

Problem

Ultrasonic welding of the current collector and electrode terminal in battery cells leads to the formation of foreign substances like fumes and spatter, causing defects and potential damage to the battery cell.

Innovation Solution

A screw-coupling method is employed to electrically connect the electrode terminal and current collector, using a connection terminal with a protrusion that engages a screw thread in a coupling groove, eliminating the need for welding and reducing the formation of foreign substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultrasonic welding is used to connect the current collector and electrode terminal, then electrical connection is achieved, but foreign substances (fumes and spatter) are formed inside the battery cell causing defects

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidforeign substances (fumes and spatter)
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent removes the welding process entirely from the battery cell assembly. Instead of welding the current collector to the electrode terminal, the invention uses a mechanical insertion structure where the current collector is inserted into a groove of the electrode terminal, eliminating the source of harmful welding fumes and spatter that contaminate the battery interior.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the ultrasonic welding process (thermal/mechanical system) with a pure mechanical insertion and fitting system. The current collector features an insertion end that fits into a groove of the electrode terminal, creating electrical connection through direct mechanical contact rather than welding, thus avoiding foreign substance generation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If ultrasonic welding is performed through the hollow portion of the electrode assembly, then the current collector and electrode terminal are electrically connected, but the electrode assembly may be damaged by welding heat

Engineering Contradiction:
Improveelectrical connectionVSAvoidelectrode assembly integrity
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent extracts the welding process from the battery assembly sequence and replaces it with a mechanical insertion method. The current collector is inserted into the electrode terminal's groove without any thermal processing, completely avoiding welding heat that could damage the electrode assembly structure.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The electrode terminal is pre-formed with a groove structure before assembly. This preliminary preparation allows the current collector to be directly inserted and connected without requiring any subsequent welding or thermal processing, preventing heat damage to the electrode assembly.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If welding is used to connect the current collector and electrode terminal, then electrical connection is established, but the process complexity and cost increase due to dust collection requirements

Engineering Contradiction:
Improveelectrical connectionVSAvoiddust collection system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the welding process and associated dust collection systems from the battery manufacturing line. By using mechanical insertion instead of welding, there is no welding dust or spatter to collect, eliminating the need for complex dust collection equipment and reducing overall system complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses simple, inexpensive mechanical components (insertion ends and grooves) that can be easily manufactured and replaced if needed, compared to expensive welding equipment and dust collection systems. The mechanical fitting is a simple, cost-effective solution that achieves the same electrical connection function.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP4607638A1Battery cell, method of manufacturing same and battery module
Publication Date: 2025.08.27 SK ON CO LTD
  • EP4607638A1 patent drawingFigure 1~2
  • EP4607638A1 patent drawingFigure 3
  • EP4607638A1 patent drawingFigure 4

AI summary

A battery cell includes a cell case including a side wall forming an accommodation space therein and a top plate having a through-hole formed therein, an electrode terminal coupled to the through-hole and having a coupling groove formed in a bottom portion of the electrode terminal, an electrode assembly disposed in the accommodation space of the cell case, and a first current collector electrically connecting the electrode terminal and the electrode assembly. The first current collector includes a connection terminal having a protrusion screw-coupled to the coupling groove, and the coupling groove includes a second screw thread coupled to a first screw thread formed on an outer peripheral surface of the protrusion.