Negative Electrode Pore Distribution for Power Output

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Solution Overview

Problem

Existing nonaqueous electrolyte cells face challenges in enhancing power output, as increasing the specific surface area of the negative electrode layer can lead to the formation of excessively fine pores, which may decrease performance.

Innovation Solution

A negative electrode with a layer containing amorphous carbon particles capable of occluding and releasing alkali or alkaline earth metals, featuring a specific surface area ratio of micropores to mesopores within a controlled range, and a binder, which is formed using a process that regulates pore distribution to improve power output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the specific surface area of the negative electrode layer is increased to obtain high energy density, then the energy density is improved, but excessively fine pores with diameter of 1 nm or smaller are formed which causes a decrease in power output

Engineering Contradiction:
Improvespecific surface areaVSAvoidpower output
Core Design Contradiction:
Quantity of substanceVSPower

Solution Approach 1:

The invention utilizes porous amorphous carbon particles with a controlled pore size distribution (micropores of 0.3-2 nm and mesopores of 2-50 nm) to achieve both high specific surface area and adequate power output. The porous structure allows sufficient surface area for high energy density while the controlled pore size prevents excessive fine pore formation that would harm power characteristics.

Inventive Principle:
Principle #31Porous materials

Solution Approach 2:

The invention changes the pore size distribution parameters by controlling the ratio of micropore specific surface area (S1) to mesopore specific surface area (S2) to be within 0.05 to 0.5. This parameter control allows optimization of both energy density and power output by balancing the surface area contribution from different pore size ranges.

Inventive Principle:
Principle #35Parameter changes

2Power

If the power output is improved by optimizing pore distribution, then the power output is enhanced, but the specific surface area may be reduced which affects energy density

Engineering Contradiction:
Improvepower outputVSAvoidspecific surface area
Core Design Contradiction:
PowerVSQuantity of substance

Solution Approach 1:

The invention uses composite amorphous carbon particles containing both micropores and mesopores in a controlled ratio. This composite pore structure combines the high surface area benefit of micropores with the power output benefit of mesopores, achieving both high energy density and high power output simultaneously.

Inventive Principle:
Principle #40Composite materials

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 solution effectively enhances power output by optimizing the pore distribution in the negative electrode layer, maintaining high performance while preventing electrolyte decomposition and ensuring sufficient conductivity.

Implementation Method 1

an active material containing an amorphous carbon particle capable of occluding and releasing at least one of an alkali metal and an alkaline earth metal

Methodology Applied
Scientific EffectIntercalation: Absorption (physical)

Implementation Method 2

ensuring sufficient conductivity

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2479821B1Negative electrode, electrode assembly and electric storage device
Publication Date: 2019.01.09 GS YUASA INT LTD
  • EP2479821B1 patent drawingFigure 1
  • EP2479821B1 patent drawingFigure 2
  • EP2479821B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide a negative electrode, an electrode assembly and an electric storage device. The negative electrode has a negative electrode layer containing: an active material containing an amorphous carbon particle capable of occluding and releasing at least one of an alkali metal and an alkaline earth metal; and a binder, the negative electrode layer having a plurality of pores; and the ratio S1/S2 of the specific surface area (S1) of micropores having a pore diameter of 1 nm or larger and 3 nm or smaller in the pores to the specific surface area (S2) of mesopores having a pore diameter of 20 nm or larger and 100 nm or smaller therein being 0.3 or higher and 0.9 or lower.