Battery Electrode Binder Composition for Heat-Stable Adhesion
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Solution Overview
Problem
Existing binder materials for electrical storage devices lack sufficient high-temperature durability and adhesiveness, which is critical for applications in electric vehicles where temperatures can exceed 50°C, leading to reduced charge-discharge characteristics and increased internal resistance.
Innovation Solution
A binder composition comprising a polymer with specific repeating units derived from conjugated diene, aromatic vinyl, and unsaturated carboxylic acid compounds, optimized to improve adhesiveness and reduce internal resistance under high temperatures, is developed. This composition includes 15-60 parts of repeating unit (a1) from conjugated diene, 35-75 parts from aromatic vinyl, and 1-10 parts from unsaturated carboxylic acid, with a dynamic viscoelasticity peak top at 0-60°C and a tanδ(100°C) of 0.1 or less.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional binder materials are used, then basic binding function is achieved, but high-temperature adhesiveness and charge-discharge durability are insufficient
Solution Approach 1:
The invention changes the chemical composition parameters of the binder by specifying precise ratios of conjugated diene units (15-60 parts), aromatic vinyl units (35-75 parts), and unsaturated carboxylic acid units (1-10 parts) per 100 parts of total repeating units. This compositional parameter optimization enables the binder to maintain adhesiveness at high temperatures while ensuring charge-discharge durability, directly resolving the contradiction between reliability and strength under thermal stress.
Solution Approach 2:
The invention creates a composite polymer structure combining three types of repeating units with complementary functions: conjugated diene provides elasticity and adhesion, aromatic vinyl provides structural stability and high-temperature resistance, and unsaturated carboxylic acid provides polar interactions for enhanced bonding. This composite material approach achieves both high-temperature adhesiveness and charge-discharge durability simultaneously.
2Strength
If binder material is increased to improve adhesiveness, then binding ability improves, but internal resistance increases
Solution Approach 1:
The invention optimizes the chemical composition parameters rather than simply increasing binder quantity. By adjusting the ratios of different repeating units (conjugated diene 15-60 parts, aromatic vinyl 35-75 parts, unsaturated carboxylic acid 1-10 parts), the binder achieves high adhesiveness with improved molecular structure that facilitates ion transport, thereby maintaining low internal resistance while enhancing binding strength.
Solution Approach 2:
The invention introduces local quality differences through the unsaturated carboxylic acid units (1-10 parts per 100 parts total), which provide polar groups for enhanced local bonding interactions with active material surfaces. This localized functional enhancement improves adhesiveness without requiring increased overall binder content, thus avoiding internal resistance increase.
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
The binder composition enhances charge-discharge durability and reduces internal resistance of electrical storage device electrodes, particularly when using high-capacity materials like silicon or graphite, improving battery performance and longevity under high-temperature conditions.
Implementation Method 1
an adhesive ability between the active material and the current collector
Implementation Method 2
reduces internal resistance of a battery resulting from the binder material
Data Source
AI summary
A binder composition for an electrical storage device, may enable production of an electrical storage device electrode excellent in charge-discharge durability characteristic under high temperature by improving adhesiveness under high temperature and reducing internal resistance. Such a composition may include: a polymer (A) and a liquid medium (B), wherein, with respect to 100 parts by mass of total repeating units in the polymer (A), the polymer (A) contains: 15 to 60 parts by mass of repeating unit (a1) derived from a conjugated diene; 35 to 75 parts by mass of repeating unit (a2) derived from an aromatic vinyl compound; and 1 to 10 parts by mass of a repeating unit (a3) derived from an unsaturated carboxylic acid, and wherein, when, in dynamic viscoelasticity measurement of the polymer (A), a peak top of tanδ (loss/storage elastic modulus) is tan8(Tp), and tanδ at 100° C. is tan8(100° C.), satisfies equation (1):tanδ100°C/tanδTp×100≤10(1)