Unit Cell Interface Measurement in Stack-Folded Battery Assemblies

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Solution Overview

Problem

It is difficult to analyze the performance of unit cells in a stack/folding type electrode assembly, which is a common configuration in secondary batteries.

Innovation Solution

A method is introduced where counter electrodes with the same polarity as the second electrode are laminated on the outermost sides of the unit cell, with electrode tabs for electrical connection, allowing for the measurement of performance differences between the first and counter electrodes, both at the outer and inner interfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If a stack/folding type electrode assembly is used to achieve compact size and high capacity, then battery energy density is improved, but the ability to analyze unit cell performance deteriorates

Engineering Contradiction:

Improvebattery capacityVSAvoidunit cell performance analysis

Core Design Contradiction:

Quantity of substanceVSDifficulty of detecting and measuring

Solution Approach 1:

The electrode assembly is divided into multiple unit cells, each with its own counter electrode and tabs. This segmentation allows individual unit cells to be measured and analyzed separately while maintaining the compact stack/folding structure, thus resolving the contradiction between high capacity and performance analyzability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Counter electrodes and electrode tabs are introduced as intermediary elements that enable electrical connection and measurement of individual unit cells. These intermediaries facilitate performance analysis without disrupting the compact stack/folding architecture, allowing both high capacity and detailed unit cell characterization.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Quantity of substance

If multiple unit cells are stacked to achieve high capacity, then battery energy density is improved, but measurement complexity increases

Engineering Contradiction:

Improvebattery capacityVSAvoidmeasurement structure

Core Design Contradiction:

Quantity of substanceVSDevice complexity

Solution Approach 1:

Multiple unit cells are merged into a single stack/folding assembly while maintaining individual measurability through shared current collectors and separators. This merging approach achieves high capacity through multiple cells while simplifying the measurement structure by using common components rather than requiring separate measurement systems for each cell.

Inventive Principle:

Principle #5Merging (Combining)

3Difficulty of detecting and measuring

If counter electrodes are added to enable unit cell measurement, then performance analysis capability is improved, but manufacturing complexity increases

Engineering Contradiction:

Improveunit cell performance analysisVSAvoidelectrode assembly manufacturing

Core Design Contradiction:

Difficulty of detecting and measuringVSEase of manufacture

Solution Approach 1:

Counter electrodes and tabs are incorporated during the initial electrode assembly manufacturing process rather than being added later for measurement purposes. This preliminary action integrates the measurement-enabling components into the standard manufacturing workflow, improving performance analysis capability without significantly increasing manufacturing complexity.

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 method enables the analysis of unit cell performance by measuring resistance and current values, improving the understanding and comparison of cell performance across different interfaces, thereby enhancing the evaluation of stack/folding type electrode assemblies.

Implementation Method 1

a separator, and a second electrode provided with a second electrode tab are alternately laminated to be bonded to each other

Methodology Applied

Scientific EffectIonic conduction: Conduction (electrical)

Implementation Method 2

electrically connecting the first electrode tab disposed on the first electrode to the third electrode tab disposed on the counter electrode

Methodology Applied

Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentUS12140638B2Method for measuring cell performance

Publication Date: 2024.11.12 LG ENERGY SOLUTION LTD

AI summary

Disclosed is a method for measuring cell performance. The method for manufacturing performance of a unit cell, in which a first electrode provided with a first electrode tab, a separator, and a second electrode provided with a second electrode tab are alternately laminated to be bonded to each other, comprises an additional lamination step of further laminating counter electrodes, each of which has the same polarity as that of the second electrode and is provided with a third electrode tab, on sides facing the first electrode at the outermost sides of the unit cell with the separator therebetween, and an outer interface analysis step of measuring a different in performance between the first electrode and each of the counter electrodes by electrically connecting the first electrode tab disposed on the first electrode to the third electrode tab disposed on the counter electrode.