Cathode Binder and Electrolyte Pairing for Low-Temperature Batteries

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Solution Overview

Problem

Conventional secondary battery binders like polyvinylidene difluoride (PVDF) cause slurry instability and environmental pollution, leading to decreased battery performance and non-compliance with green development requirements.

Innovation Solution

Using polyvinyl butyral in the positive electrode and a specific combination of lithium difluorophosphate and trinitrile compounds in the electrolyte to enhance electrode cohesion and reduce initial resistance and improve low-temperature performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If PVDF is used as the binding material for forming the positive composite material layer, then the binding material provides adequate adhesion, but the slurry stability decreases due to gelation and environmental pollution occurs

Engineering Contradiction:

ImproveadhesionVSAvoidslurry stability

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The patent changes the chemical composition parameters of the binding material from PVDF to polyvinyl butyral, which has different gelation characteristics and environmental properties. This parameter change resolves the contradiction by maintaining adhesion while eliminating slurry instability and environmental pollution

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the expensive and environmentally problematic PVDF with a more economical and environmentally friendly polyvinyl butyral that does not cause gelation issues, effectively substituting a material with shorter environmental persistence and lower cost

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Ease of manufacture

If PVDF is used as the binding material, then the positive composite material layer can be formed, but environmental pollution occurs and green development requirements are not met

Engineering Contradiction:

ImprovemanufacturabilityVSAvoidenvironmental pollution

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent converts the harmful environmental factor of PVDF (fluorine-containing binder pollution) into a beneficial outcome by using polyvinyl butyral, which is environmentally friendly and meets green development requirements while maintaining manufacturing effectiveness

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The patent changes the chemical composition from fluorine-containing PVDF to oxygen-containing polyvinyl butyral, fundamentally altering the environmental impact parameter while preserving the manufacturing function of the binding material

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentEP4708403A1Secondary battery and electronic device

Publication Date: 2026.03.11 NINGDE AMPEREX TECHNOLOGY LTD

AI summary

A secondary battery, including: a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive current collector and a positive active material layer formed on the positive current collector, the positive active material layer includes a positive active material and polyvinyl butyral, and the electrolyte includes lithium difluorophosphate and a trinitrile compound. A shedding resistance of the positive electrode is improved, an initial resistance of the secondary battery is further reduced, and a low-temperature rate characteristic is further improved.