Secondary Battery Electrode Layout for Fast-Charge Electrolyte Permeation

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Solution Overview

Problem

The rapid charge and discharge characteristics of secondary batteries deteriorate due to the close contact between the insulator and separator at the exposed portion of the core, which impedes electrolyte permeation and increases the risk of internal short circuits.

Innovation Solution

The electrode design includes a longitudinal-direction-side exposed portion covered with an insulator and a lateral-direction-side exposed portion separated from the core ends, allowing electrolyte permeation while preventing internal short circuits, with a thinner mixture layer thickness in specific regions to enhance charge and discharge efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the exposed portion at the end in the longitudinal direction of the core is covered with an insulator, then internal short circuits are suppressed, but the electrolytic solution permeation is impeded and rapid charge and discharge characteristics deteriorate

Engineering Contradiction:
Improveinternal short circuit suppressionVSAvoidrapid charge and discharge characteristics
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The insulator is segmented into two distinct parts: a first insulator covering the exposed portion at the longitudinal end, and a second insulator covering the exposed portion at the lateral end. This segmentation allows each insulator to perform its specific function independently - the first insulator prevents internal short circuits while the second insulator maintains electrolyte permeation pathways, thereby resolving the contradiction between reliability and productivity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different insulating properties are applied to different locations of the core. The first insulator is positioned at the longitudinal end where internal short circuit prevention is critical, while the second insulator is positioned at the lateral end where electrolyte permeation is essential. This local differentiation of insulator placement and configuration allows simultaneous optimization of both reliability and rapid charge-discharge characteristics

Inventive Principle:
Principle #3Local quality

2Stability of the object's composition

If the insulator is provided at the end in the longitudinal direction on the core, then peeling-off of the mixture layer is suppressed, but the close contact with the separator impedes electrolyte permeation

Engineering Contradiction:
Improvemixture layer stabilityVSAvoidelectrolyte permeation
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The insulating function is segmented between two insulators positioned at different locations. The first insulator at the longitudinal end provides mechanical support to prevent mixture layer peeling-off, while the second insulator at the lateral end is configured to maintain electrolyte permeation pathways, thus resolving the contradiction between mixture layer stability and electrolyte permeation

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The second insulator acts as an intermediary element between the lateral exposed portion and the separator. By positioning and configuring this insulator appropriately, it mediates the interaction to prevent direct close contact that would block electrolyte permeation, while still providing necessary insulation and structural support

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4718508A1Electrode for secondary batteries, and secondary battery
Publication Date: 2026.04.01 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
  • EP4718508A1 patent drawingFigure 1
  • EP4718508A1 patent drawingFigure 2~3
  • EP4718508A1 patent drawingFigure 4~5

AI summary

Provided is an electrode for secondary batteries, which is capable of suppressing deterioration of rapid charge and discharge characteristics. An electrode (30) for secondary batteries constitutes a winding-type electrode body provided with a band-like core body (32) and a mixture layer (34) disposed on the core body (32), and is characterized in that: a longitudinal-direction-side first exposed portion (36), in which the mixture layer (34) is not disposed, is provided at one end part in the longitudinal direction of the core body (32); the longitudinal-direction-side first exposed portion (36) is covered with a first insulating portion (38); and a short-direction-side first exposed portion (44), in which the mixture layer (34) is not disposed, is provided at a position separated from both end parts in the longitudinal direction of the core body (32) at one end part in the short direction of the core body (32).