Cable Battery Sheet Electrodes Reduce Resistance

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Solution Overview

Problem

Current secondary batteries face limitations in shape adaptability, electrolyte permeation, and performance due to their cylindrical or prismatic shapes, leading to reduced capacity and cycle characteristics, especially in cable-type batteries with non-uniform gaps and high resistance wire-type current collectors.

Innovation Solution

A cable-type secondary battery design featuring a sheet-type inner and outer electrode structure spirally wound on an inner electrode support with an open structure, allowing for easy electrolyte permeation and reduced resistance, using a sheet-type current collector and polymer film layers for improved flexibility and capacity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If a wire-type current collector is used in cable type secondary battery, then the battery can be formed with linear structure, but the line resistance is higher than sheet resistance causing higher resistance characteristics and degraded battery performance

Engineering Contradiction:
Improvelinear structureVSAvoidbattery performance
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies this principle by using a sheet-type current collector instead of a wire-type current collector. The sheet-type structure provides lower resistance characteristics while maintaining the flexibility needed for linear cable battery formation, directly resolving the contradiction between linear shape and battery performance

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent changes the physical form parameter from wire-type to sheet-type current collector. This parameter change reduces the resistance characteristics from high (wire-type) to low (sheet-type), thereby improving battery performance while maintaining linear structure capability

Inventive Principle:
Principle #35Parameter changes

2Shape

If non-uniform gap is created between inner electrode and outer electrode with separation layer, then the battery structure can be formed, but the electrolyte solution feeding into outer electrode active material layer is not smooth causing degraded battery performance

Engineering Contradiction:
Improvebattery structureVSAvoidbattery performance
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies this principle by ensuring uniform gap distribution between the inner electrode and outer electrode throughout the battery structure. This local uniformity in gap quality enables smooth electrolyte solution feeding into the outer electrode active material layer, resolving the performance degradation issue

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent creates a uniform gap structure that ensures equipotential distribution of electrolyte flow paths. This uniformity allows smooth and consistent electrolyte solution feeding across the entire outer electrode active material layer, improving battery performance

Inventive Principle:
Principle #12Equipotentiality

3Shape

If polymer electrolyte is used to form electrolyte layer in linear battery, then the battery can be formed with linear structure, but it is difficult for electrolyte to permeate into active material of electrode resulting in increased battery resistance and reduced capacity and cycle characteristics

Engineering Contradiction:
Improvelinear structureVSAvoidcapacity and cycle characteristics
Core Design Contradiction:
ShapeVSReliability

Solution Approach 1:

The patent applies this principle by using a liquid electrolyte solution instead of a polymer electrolyte layer. The liquid electrolyte provides superior permeation into the electrode active material through capillary action and fluid flow, dramatically reducing battery resistance and improving capacity and cycle characteristics while maintaining linear structure

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design enhances battery performance by reducing internal resistance, improving electrolyte access to active materials, and maintaining stability under external forces, resulting in superior capacity and cycle characteristics while allowing for flexible shape adaptation.

Implementation Method 1

an inner electrode including a sheet-type first inner electrode formed such that it is spirally wound on an exterior of the inner electrode support, a sheet-type inner separation layer formed such that it is spirally wound on an exterior of the first inner electrode, and a sheet-type second inner electrode formed such that it is spirally wound on an exterior of the inner separation layer

Methodology Applied
Scientific EffectSpiral winding: Helix

Data Source

PatentEP3244476B1Cable type secondary battery
Publication Date: 2019.12.11 LG CHEM LTD
  • EP3244476B1 patent drawingFigure 1
  • EP3244476B1 patent drawingFigure 2
  • EP3244476B1 patent drawingFigure 3

AI summary

Provided is a cable type secondary battery comprising: an inner electrode support; and a sheet-like inner electrode - separation layer - outer electrode complex which is spirally wound around the outer side of the inner electrode support, wherein the inner electrode - separation layer - outer electrode complex is formed such that an inner electrode, a separation layer which prevents an electrode from shorting, and an outer electrode are compressed integrally. According to one embodiment of the present invention, an electrode and a separation layer are bonded integrally so that the separation layer in close contact with the electrode absorbs electrolyte so as to induce a uniform supply of the electrolyte to an outer electrode active material layer, thereby increasing the stability and performance of a cable type secondary battery. In addition, the cable type secondary battery has a sheet-like electrode, excluding a wire type current collector having a high resistance, whereby the resistance of the cable type secondary battery is reduced and the performance of the battery may be improved. Further, since the cable type secondary battery has an inner electrode support with an open structure and a sheet-like electrode-separation layer complex is wound spirally like a spring structure, it is possible to maintain a linear shape and mitigate stress caused by external forces.