Negative Electrode Orientation for Battery Resistance

Solution Overview

Problem

Lithium ion secondary batteries for vehicles face challenges in achieving low reaction resistance and improved input and output properties, particularly in retaining the orientation of graphite material with (002) planes perpendicular to the negative electrode current collector during compaction, leading to deterioration of performance.

Innovation Solution

A non-aqueous electrolyte secondary battery design featuring a negative electrode with a conductive base accumulated layer and a negative electrode active material layer where at least 50% of the charge carriers are oriented at an angle of 45° to 90° relative to the current collector, using a minute conductive material with a smaller average particle diameter than the active material, and applying a magnetic field to maintain orientation during production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If graphite material is oriented with (002) planes perpendicular to the current collector to improve lithium ion insertion/extraction, then charge and discharge capacity is improved, but orientation is difficult to retain during compaction treatment

Engineering Contradiction:

Improvecharge and discharge capacityVSAvoidorientation retention during compaction

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies magnetic field orientation to the graphite material before compaction treatment to establish the desired perpendicular orientation of (002) planes. This preliminary orientation action ensures that the graphite crystallites are properly aligned prior to the compaction process, allowing the orientation to be retained during subsequent manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical compaction methods with a combination of magnetic field application and controlled compaction. By using magnetic fields to orient the graphite material before compaction, the system substitutes mechanical orientation attempts with a magnetic field-based approach that achieves and maintains the desired orientation more effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If magnetic field orientation is applied to graphite material to improve lithium migration, then charge and discharge capacity is improved, but input and output properties deteriorate due to orientation loss during compaction

Engineering Contradiction:

Improvecharge and discharge capacityVSAvoidinput and output properties

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The patent applies magnetic field orientation to the graphite material before compaction treatment to establish the desired perpendicular orientation of (002) planes. This preliminary orientation action ensures that the graphite crystallites are properly aligned prior to the compaction process, allowing the orientation to be retained during subsequent manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical compaction methods with a combination of magnetic field application and controlled compaction. By using magnetic fields to orient the graphite material before compaction, the system substitutes mechanical orientation attempts with a magnetic field-based approach that achieves and maintains the desired orientation more effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Quantity of substance

If compaction treatment is applied to increase electrode density, then energy density is improved, but graphite material orientation is lost leading to increased resistance

Engineering Contradiction:

Improveelectrode densityVSAvoidresistance increase due to orientation loss

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The patent applies magnetic field orientation to the graphite material before compaction treatment to establish the desired perpendicular orientation of (002) planes. This preliminary orientation action ensures that the graphite crystallites are properly aligned prior to the compaction process, allowing the orientation to be retained during subsequent manufacturing steps.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces purely mechanical compaction methods with a combination of magnetic field application and controlled compaction. By using magnetic fields to orient the graphite material before compaction, the system substitutes mechanical orientation attempts with a magnetic field-based approach that achieves and maintains the desired orientation more effectively.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 battery with low resistance and enhanced input and output properties, maintaining high orientation of the negative electrode active material and achieving improved capacitance characteristics.

Implementation Method 1

applying a magnetic field to maintain orientation during production

Methodology Applied

Scientific EffectMagnetic field orientation: Magnetic Field

Data Source

PatentUS9911972B2Non-aqueous electrolyte secondary battery and method for manufacturing negative electrode for secondary battery

Publication Date: 2018.03.06 TOYOTA JIDOSHA KK

AI summary

The non-aqueous electrolyte secondary battery 10 provided by the present invention comprises a positive electrode 30, a negative electrode 50 and a non-aqueous electrolyte. The negative electrode 50 includes a negative electrode current collector 52 and a negative electrode active material layer 54 formed on the current collector 52, the negative electrode active material layer 54 containing a negative electrode active material 55 capable of storing and releasing charge carriers and having shape anisotropy so that the charge carriers are stored and released along a predefined direction. The negative electrode active material layer 54 includes, at a bottom thereof contacting the current collector 52, a minute conductive material 57 with granular shape and/or minute conductive material 57 with fibrous shape having an average particle diameter that is smaller than that of the negative electrode active material 55, and includes, at the bottom thereof; a part of the negative electrode active material 55. At least 50% by number of the total amount of the negative electrode active material 55 is oriented so that the direction of storage and release of the charge carriers is at an angle of 45° or more and 90° or less relative to the surface of the current collector 52.