Secondary Battery Electrode With Piercing Active Material

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Solution Overview

Problem

Existing secondary battery electrodes face challenges in achieving high capacity density and output while maintaining thinness, as increasing the volume ratio of the current collector decreases electrical conduction properties and capacity density.

Innovation Solution

The electrode design includes a current collector with a particulate active material that pierces through both faces, increasing the contact area and reducing the volume ratio of the current collector, using lithium composite metal oxides with specific particle diameters for improved lithium ion conduction and a metal or electrically conductive resin material for reduced resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the positive electrode is thinned to achieve high output and capacity density, then the volume of the current collector increases relative to the positive electrode, but the capacity density decreases

Engineering Contradiction:

Improvecapacity densityVSAvoidvolume ratio of current collector

Core Design Contradiction:

ProductivityVSQuantity of substance

Solution Approach 1:

The active material is positioned to protrude from both surfaces of the current collector, transitioning from a planar configuration to a three-dimensional structure. This dimensional change allows the active material to occupy space extending beyond the current collector boundaries, effectively increasing the active material volume while maintaining a thin current collector, thereby resolving the contradiction between thin electrode design and sufficient active material content for high capacity density

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If the content ratio of binder or fluorine-based polymer is increased to prevent peeling, then adhesion improves, but electrical conduction property decreases

Engineering Contradiction:

Improveadhesion between current collector and active material layerVSAvoidelectrical conduction property

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The invention extracts the active material from the conventional planar layer configuration and positions it to protrude from both surfaces of the current collector. This extraction allows the active material to be in direct contact with the current collector over a larger surface area, reducing the dependency on binder and fluorine-based polymer for adhesion. Consequently, the content ratio of these non-conductive materials can be reduced, thereby maintaining or improving electrical conduction property while still ensuring reliable adhesion

Inventive Principle:

Principle #2Taking out (Extraction)

3Loss of energy

If electrical conduction aid is added to ensure electrical conduction property, then conduction improves, but the volume ratio of active material decreases, ending up with decreased capacity density

Engineering Contradiction:

Improveelectrical conduction propertyVSAvoidcapacity density

Core Design Contradiction:

Loss of energyVSProductivity

Solution Approach 1:

By positioning the active material to protrude from both surfaces of the current collector, the invention creates a three-dimensional configuration that increases the volume of active material without requiring additional electrical conduction aids. This dimensional change allows the active material to extend into the space beyond the current collector planes, effectively increasing capacity density while maintaining electrical conduction through direct contact with the current collector, eliminating the need to add non-active electrical conduction aids that would reduce active material volume ratio

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration results in a thinner, high-capacity-density secondary battery with improved output and reduced internal resistance, while also ensuring chemical stability and adhesion between components.

Implementation Method 1

an active material in a particulate form which pierces the current collector and is exposed from the first face and the second face

Methodology Applied

Scientific EffectPhysical penetration and contact:

Implementation Method 2

a positive electrode active material which pierces the current collector and is exposed from the first face and the second face... lithium composite metal oxides with specific particle diameters for improved lithium ion conduction

Methodology Applied

Scientific EffectLithium ion conduction: Conduction (electrical)

Data Source

PatentUS10756329B2Electrode for secondary battery, secondary battery, and electronic apparatus

Publication Date: 2020.08.25 SEIKO EPSON CORP

AI summary

A lithium battery as a secondary battery has a battery cell including a first current collector which has a first face and a second face, a positive electrode active material particle which pierces the first current collector and is exposed from the first face and the second face, an electrolyte layer which covers the positive electrode active material particle exposed from the first face and the second face of the first current collector, a negative electrode as an electrode which is in contact with the electrolyte layer, and a second current collector which is in contact with the negative electrode. The battery cell is hermetically enclosed in a package in a state where one end portion which is a portion of the first current collector is exposed.