Positive Electrode Copolymer Dispersant for High-Voltage Stability
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Solution Overview
Problem
Existing dispersants for positive electrodes in power storage devices tend to decompose at high voltages, leading to battery degradation due to gas generation.
Innovation Solution
A copolymer dispersant is used, comprising a constitutional unit A and at least one constitutional unit B, which improves the dispersibility of conductive materials and reduces decomposition even at high voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional dispersants are used in positive electrode paste, then conductive materials can be dispersed, but the dispersant decomposes at high voltages causing battery degradation
Solution Approach 1:
The patent changes the chemical composition parameters of the dispersant by using a copolymer with specific constitutional units (unit A with general formula (1) and unit B with general formula (2) or (3)). This compositional parameter change enables the dispersant to maintain stability at high voltages while retaining dispersing capability, thus preventing decomposition and gas generation.
Solution Approach 2:
The patent employs a copolymer dispersant composed of multiple constitutional units (unit A and unit B) with different functional characteristics. Unit A provides dispersing functionality while unit B contributes to voltage stability. This composite structure at the molecular level allows the dispersant to simultaneously achieve dispersion and high-voltage stability, preventing decomposition.
2Quantity of substance
If battery voltage is increased to improve energy density, then energy density improves, but dispersant decomposition is accelerated
Solution Approach 1:
The patent modifies the chemical structure parameters of the dispersant by incorporating constitutional units with specific molecular formulas. Unit A (with general formula (1)) and unit B (with general formula (2) or (3)) are designed to withstand high voltage conditions, enabling the battery to operate at higher voltages for improved energy density without causing dispersant decomposition.
3Reliability
If copolymer dispersant with specific constitutional units is used, then high voltage stability is achieved, but dispersibility of conductive materials must be maintained
Solution Approach 1:
The copolymer dispersant combines constitutional unit A (providing dispersing functionality through its molecular structure with general formula (1)) and constitutional unit B (providing voltage stability through its structure with general formula (2) or (3))). This composite molecular structure enables the dispersant to simultaneously achieve excellent dispersibility of conductive materials and high voltage stability without compromising either function.
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 use of this copolymer dispersant enhances the stability of the positive electrode, reducing direct current resistance and maintaining battery capacity over time.
Implementation Method 1
a first constitutional unit A represented by the following general formula (1)... which is adsorbed on a conductive material
Implementation Method 2
reducing direct current resistance
Data Source
Figure 1~2
AI summary
The present invention relates to a dispersant for a positive electrode of a power storage device. The dispersant is a copolymer that contains a constitutional unit A represented by the following general formula (1) and at least one constitutional unit B selected from the group consisting of a constitutional unit B1 represented by the following general formula (2) and a constitutional unit B2 represented by the following general formula (3). The total content of the constitutional unit A and the constitutional unit B in the copolymer is 80% by mass or more. The content of the constitutional unit A in all constitutional units of the copolymer is 35% by mass or more.