Battery Cell Terminal Structure for External Current Collector Welding

Solution Overview

Problem

Conventional battery cells face defects due to foreign substances and damage from ultrasonic welding of the electrode terminal and current collector, which can affect the internal configuration and rigidity, and make it difficult to confirm welding quality.

Innovation Solution

A battery cell design where the electrode terminal and current collector are welded outside the cell case, using a protrusion and welding space formed between the electrode terminal and a connection terminal, allowing for external welding and improved rigidity, with a cross-sectional reduction portion to control welding heat and prevent foreign substances.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ultrasonic welding is performed through the hollow space of the electrode assembly inside the cell case, then the current collector and electrode terminal can be electrically connected, but welding foreign substances such as fume or spatter are formed inside the battery cell causing defects

Engineering Contradiction:

Improveelectrical connection qualityVSAvoidwelding foreign substances inside cell

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The welding operation is extracted from the internal hollow space of the electrode assembly and relocated to the external environment. The current collector is designed with an exposed portion that extends outside the cell case, allowing welding to be performed externally where fume and spatter can be effectively removed without contaminating the battery interior.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The exposed portion of the current collector acts as an intermediary element that bridges the internal electrical connection requirement and the external welding environment. This mediator allows the welding process to occur outside the cell while still achieving the required electrical connection between the current collector and electrode terminal.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If welding is performed inside the cell case through the hollow space, then electrical connection is achieved, but the electrode assembly is damaged by welding heat

Engineering Contradiction:

Improveelectrical connectionVSAvoidwelding heat damage to electrode assembly

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The welding operation is extracted from the internal hollow space of the electrode assembly and relocated to the external environment. The current collector is designed with an exposed portion that extends outside the cell case, allowing welding to be performed externally where fume and spatter can be effectively removed without contaminating the battery interior.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The exposed portion of the current collector acts as an intermediary element that bridges the internal electrical connection requirement and the external welding environment. This mediator allows the welding process to occur outside the cell while still achieving the required electrical connection between the current collector and electrode terminal.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Volume of stationary object

If the current collector is fully inserted inside the cell case, then space is optimized, but welding quality cannot be easily confirmed and rigidity is reduced

Engineering Contradiction:

Improvecell case space utilizationVSAvoidwelding quality confirmation

Core Design Contradiction:

Volume of stationary objectVSDifficulty of detecting and measuring

Solution Approach 1:

The current collector is segmented into two distinct portions: an inserted portion that fits within the cell case to optimize space utilization, and an exposed portion that extends outside the cell to enable welding quality confirmation and provide structural reinforcement. This segmentation allows both space optimization and welding accessibility to be achieved simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The current collector is pre-designed with a specific structure including the exposed portion before assembly into the cell case. This preliminary design ensures that the welding area is readily accessible and that the rigidity requirements are met before the welding operation is performed, eliminating the need for post-assembly modifications.

Inventive Principle:

Principle #10Preliminary action

4Volume of stationary object

If the current collector is fully inserted inside the cell case, then space is optimized, but the rigidity of the electrode terminal connection is reduced

Engineering Contradiction:

Improvecell case space utilizationVSAvoidelectrode terminal rigidity

Core Design Contradiction:

Volume of stationary objectVSStrength

Solution Approach 1:

The current collector is segmented into two distinct portions: an inserted portion that fits within the cell case to optimize space utilization, and an exposed portion that extends outside the cell to enable welding quality confirmation and provide structural reinforcement. This segmentation allows both space optimization and welding accessibility to be achieved simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The current collector is pre-designed with a specific structure including the exposed portion before assembly into the cell case. This preliminary design ensures that the welding area is readily accessible and that the rigidity requirements are met before the welding operation is performed, eliminating the need for post-assembly modifications.

Inventive Principle:

Principle #10Preliminary action

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 design prevents foreign substances from entering the cell, reduces damage to the electrode assembly, and allows easy confirmation of welding quality, enhancing the cell's integrity and efficiency.

Implementation Method 1

a welding area WA may be formed in the welding space WS by welding performed on an outer side (outside) of the cell case in a state in which the protrusion 133b is inserted into the coupling hole 145

Methodology Applied

Scientific EffectWelding: Welding

Data Source

PatentEP4607661A1Battery cell, manufacturing method thereof and battery module

Publication Date: 2025.08.27 SK ON CO LTD

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AI summary

The present disclosure provides a battery cell including: a cell case including a side wall having an accommodation space and an upper plate having a through-hole; an electrode terminal coupled to the through-hole and having a coupling hole; an electrode assembly disposed in the accommodation space; and a first current collector electrically connecting the electrode terminal and the electrode assembly, where the first current collector includes a connection terminal having a protrusion inserted into the coupling hole, a welding space is formed between an upper end of a side surface of the protrusion and an inner surface of the coupling hole, and a welding area is formed in the welding space by welding performed on an outer side of the cell case in a state in which the protrusion is inserted into the coupling hole.