Negative Electrode Coating for Battery Heat Resistance and Outflow

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Solution Overview

Problem

Existing methods for manufacturing negative electrodes for non-aqueous electrolyte secondary batteries face challenges in simultaneously providing a heat-resistant film and an outflow suppression film, requiring different materials for the planar and side-surface regions, which complicates the manufacturing process.

Innovation Solution

A method involving the use of a common application material containing heat-resistant particles and thermoplastic resin particles, where the planar coating film is heated above the melting point of the thermoplastic resin particles to create a porous heat-resistant film, and the side-surface coating film is dried without melting the thermoplastic resin particles to prevent electrolyte outflow, thereby simplifying the process and reducing the number of drying steps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different materials are used for planar coating film and side-surface coating film to provide both heat-resistant film and outflow suppression film, then both heat resistance and electrolyte outflow suppression are achieved, but manufacturing process complexity increases

Engineering Contradiction:

Improveelectrolyte outflow suppressionVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by using a single application material containing both heat-resistant particles and thermoplastic resin particles for both the planar region and side-surface region coatings. This multi-functional material allows the same coating composition to serve different purposes in different regions after differential processing, eliminating the need for separate materials and reducing manufacturing complexity while maintaining both heat-resistant and outflow-suppression functions

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent applies local quality by implementing different thermal processing conditions for different regions: the planar coating film is heated above the melting point of thermoplastic resin particles to form a porous heat-resistant film, while the side-surface coating film is dried at a temperature below the melting point to maintain particle integrity for electrolyte outflow suppression. This regional differentiation in processing temperature creates the desired functional differences from a uniform material composition

Inventive Principle:

Principle #3Local quality

2Reliability

If multiple drying steps are used to process both planar and side-surface coating films differently, then functional differentiation is achieved, but manufacturing time increases

Engineering Contradiction:

Improvefilm function differentiationVSAvoidmanufacturing time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies parameter changes by utilizing the melting point of thermoplastic resin particles as a critical threshold parameter. By controlling the drying temperature to be below this melting point, the process achieves functional differentiation between planar and side-surface coating films in a single drying step, eliminating the need for multiple sequential drying operations and reducing manufacturing time while maintaining film function differentiation

Inventive Principle:

Principle #35Parameter changes

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 approach effectively suppresses electrolyte outflow and maintains charge exchange efficiency, reducing the rate of resistance increase in high-rate cycles, making it suitable for applications like hybrid and electric vehicles.

Implementation Method 1

heating the planar coating film at a temperature not lower than a melting point of the thermoplastic resin particles; Melting at least some of the thermoplastic resin particles into a melt

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

drying the planar coating film containing the melt and the side-surface coating film containing the thermoplastic resin particles at a temperature lower than the melting point of the thermoplastic resin particles

Methodology Applied

Scientific EffectEvaporation: Evaporation

Data Source

PatentUS10566610B2Method of manufacturing negative electrode for non-aqueous electrolyte secondary battery, and method of manufacturing non-aqueous electrolyte secondary battery

Publication Date: 2020.02.18 TOYOTA JIDOSHA KK

AI summary

A method of manufacturing a negative electrode for a non-aqueous electrolyte secondary battery includes the following. A negative electrode composite material layer including a planar region and a side-surface region is formed. An application material is prepared by mixing heat-resistant particles, thermoplastic resin particles, and a solvent. A planar coating film is formed by applying the application material to the planar region and a side-surface coating film is formed by applying the application material to the side-surface region. At least some of the thermoplastic resin particles are molten into a melt by heating the planar coating film at a temperature not lower than a melting point of the thermoplastic resin particles. A negative electrode is manufactured by drying the planar coating film containing the melt and the side-surface coating film containing the thermoplastic resin particles at a temperature lower than the melting point of the thermoplastic resin particles.