Laminated Electrode Body Manufacturing via Curved Wound Cutting

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Solution Overview

Problem

The manufacturing of laminated electrode bodies for nonaqueous electrolyte secondary batteries, such as lithium ion batteries, is complicated and costly, with existing zigzag lamination methods requiring complex devices and risking short circuits, which reduces productivity and increases production costs.

Innovation Solution

A method involving the preparation of a wound body with flat and curved portions, cutting out the curved portions to create a laminate structure, and removing active materials on the cut surfaces using an inactive gas or insulating particles while applying a voltage of 25 V or more, but less than the dielectric breakdown voltage of the separator, to prevent short circuits and simplify the manufacturing process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If electrodes are disposed in a zigzag manner to simplify manufacturing, then manufacturing complexity is reduced, but device complexity increases and productivity decreases

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoiddevice configuration complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The electrode sheets are divided into multiple segments along the width direction, with insulating partitions placed between segments. This segmentation allows the electrodes to be disposed in a zigzag manner while preventing short circuits, thereby simplifying the manufacturing process without requiring complex devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Insulating partitions are introduced as intermediary elements between adjacent electrode sheets in the zigzag configuration. These partitions act as mediators that prevent direct contact between positive and negative electrodes, enabling the simplified zigzag arrangement while maintaining electrical insulation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Volume of moving object

If regions where positive and negative electrode sheets cross are punched out to resolve space efficiency, then space efficiency is improved, but short circuits may occur and yield reduces

Engineering Contradiction:

Improvespace efficiencyVSAvoidshort circuit prevention

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

Insulating partitions are used as disposable insulating elements placed at potential short circuit locations. Rather than punching out electrode regions (which risks creating short circuits), these partitions provide a simple, reliable, and cost-effective solution to prevent short circuits while maintaining space efficiency.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Stability of the object's composition

If multiple positive and negative electrode sheets are laminated one by one to achieve uniform battery reaction, then battery reaction uniformity is improved, but manufacturing complexity increases and productivity decreases

Engineering Contradiction:

Improvebattery reaction uniformityVSAvoidmanufacturing efficiency

Core Design Contradiction:

Stability of the object's compositionVSProductivity

Solution Approach 1:

Multiple electrode sheets are combined into a single laminate structure with insulating partitions integrated throughout. This merging approach allows all electrode sheets to be assembled simultaneously rather than laminated one by one, significantly improving manufacturing efficiency while maintaining uniform battery reaction through the integrated insulating design.

Inventive Principle:

Principle #5Merging (Combining)

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 allows for the use of conventional devices, reduces production costs, prevents short circuits, and shortens manufacturing time, resulting in improved productivity and cost efficiency while maintaining space efficiency and uniform battery reaction.

Implementation Method 1

applying, to the electrode laminate structure, a voltage of 25 V or more and less than a voltage causing a dielectric breakdown of the separator

Methodology Applied

Scientific EffectDielectric breakdown: Avalanche Breakdown

Implementation Method 2

spraying an inactive gas or electrically insulating particles onto the cut surfaces while applying, to the electrode laminate structure, a voltage of 25 V or more

Methodology Applied

Scientific EffectElectrostatics: Electrostatics

Data Source

PatentUS10923771B2Method for manufacturing laminated electrode body

Publication Date: 2021.02.16 TOYOTA JIDOSHA KK

AI summary

Provided is a method for manufacturing a laminated electrode body which is excellent in terms of productivity and production cost. The method for manufacturing a laminated electrode body disclosed herein includes the steps of: preparing a wound body having a flat portion and two curved portions by using a laminate formed of an elongated positive electrode, an elongated negative electrode, and an elongated separator that insulates the positive electrode and the negative electrode from each other; preparing an electrode laminate structure having two cut surfaces by cutting out and removing the two curved portions of the wound body; and removing active materials on the cut surfaces of the electrode laminate structure by spraying an inactive gas or electrically insulating particles onto the cut surfaces while applying, to the electrode laminate structure, a voltage of 25 V or more and less than a voltage causing a dielectric breakdown of the separator.