Pouch Cell Edge Pressing for Low-Voltage Short-Circuit Inspection

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Solution Overview

Problem

Current methods for detecting low-voltage defective secondary battery cells, particularly pouch-type cells, are inefficient due to weak pressing in existing inspection devices, leading to incomplete short-circuit detection and separate equipment requirements for pressurizing short-circuit inspection and cell pressurizing processes, which increase costs and reduce productivity.

Innovation Solution

A pressurizing short-circuit inspection apparatus with compression plates and a movable pressurizing short-circuit inspection assembly that includes a cell pressing unit with balls for intense pressure on the cell edges and a power supply unit to apply a test voltage, allowing for integrated pressurizing short-circuit inspection and cell pressurizing processes using a single device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a jig in the shape of `[+]' is used to press the cell body for short-circuit inspection, then the inspection can be performed, but the pressing force is too weak to properly induce temporary short-circuit in defective separator areas

Engineering Contradiction:
Improvedetection accuracyVSAvoidpressing force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent applies local quality by using multiple pressing rollers that can independently apply pressing force to specific edge areas of the cell where separator defects are most likely to occur. Instead of uniform weak pressing across the entire cell body, the system concentrates pressing force at critical locations (edge areas) to induce temporary short-circuit in defective regions, thereby improving detection accuracy without requiring excessive overall pressing force.

Inventive Principle:
Principle #3Local quality

2Reliability

If separate equipment is used for pressurizing short-circuit inspection and cell pressurizing processes, then each process can be optimized independently, but costs increase and productivity decreases

Engineering Contradiction:
Improveprocess optimizationVSAvoidproduction efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent merges the pressurizing short-circuit inspection process and the cell pressurizing process into a single integrated apparatus. The same pressing rollers and pressurization mechanism used for cell pressurizing are also utilized for short-circuit inspection by applying test voltage during the pressurizing operation. This eliminates the need for separate inspection equipment, reduces costs, increases productivity by combining two processes into one operational sequence, and maintains process optimization through coordinated control of pressing force and voltage application.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If separate equipment is used for pressurizing short-circuit inspection and cell pressurizing processes, then each process can be optimized independently, but device complexity and space requirements increase

Engineering Contradiction:
Improveprocess optimizationVSAvoidequipment structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing the pressurizing apparatus to serve dual functions: cell pressurizing and short-circuit inspection. The pressing rollers, pressurization mechanism, and control system are configured to perform both processes using the same hardware infrastructure. This multi-functional design reduces device complexity, minimizes space requirements, and eliminates redundant components while maintaining the ability to optimize both processes through coordinated operation.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If uniform pressing is applied across the entire cell body, then the structure is simple, but it fails to effectively induce short-circuit in edge area defects

Engineering Contradiction:
Improvepressing structureVSAvoiddefect detection capability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies local quality by using multiple pressing rollers that can independently apply pressing force to specific edge areas of the cell where separator defects are most likely to occur. Instead of uniform weak pressing across the entire cell body, the system concentrates pressing force at critical locations (edge areas) to induce temporary short-circuit in defective regions, thereby improving detection accuracy without requiring excessive overall pressing force.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by making the pressing rollers movable along the cell body, allowing the pressing locations to be dynamically adjusted to target specific edge areas where defects are suspected. The system can adaptively position and apply pressing force at different locations based on defect probability maps or inspection requirements, enhancing detection capability while maintaining a relatively simple overall structure.

Inventive Principle:
Principle #15Dynamics

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 solution enables reliable detection of defective cells by inducing a temporary short-circuit state and applying a test voltage, improving inspection accuracy and reducing costs and space requirements by integrating two processes into one device.

Implementation Method 1

a power supply unit provided in contact with an electrode lead (6a) of the secondary battery cell (6) to apply a test voltage

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Implementation Method 2

a cell pressing unit configured to press a predetermined region of a body of the secondary battery cell (6)

Methodology Applied
Scientific EffectMechanical compression: Compression

Data Source

PatentEP3907809B1Pressurizing short-circuit inspection apparatus for detecting low-voltage defective pouch-type secondary battery cell
Publication Date: 2024.02.07 LG ENERGY SOLUTION LTD
  • EP3907809B1 patent drawingFigure 1
  • EP3907809B1 patent drawingFigure 2~3
  • EP3907809B1 patent drawingFigure 4

AI summary

Disclosed is a pressurizing short-circuit inspection apparatus, which includes compression plates arranged with a predetermined separation distance therebetween so that at least one of secondary battery cells is inserted therein, the compression plates being moved in ±X-axis direction to adjust the separation distance; and a pressurizing short-circuit inspection assembly having a cell pressing unit configured to press a predetermined region of a body of the secondary battery cell and a power supply unit provided in contact with an electrode lead of the secondary battery cell to apply a test voltage, the pressurizing short-circuit inspection assembly being respectively mounted to the compression plates to be movable along ±Y-axis direction.