Flexible Lithium Ion Cell Non-Bound Electrode Design

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Solution Overview

Problem

Lithium ion cells face challenges in achieving both flexibility and high power density or large capacity while maintaining mechanical durability, as existing technologies struggle with deformation-induced gaps in active material layers, which disrupt charge and discharge characteristics.

Innovation Solution

A lithium ion cell design featuring a non-bound positive and negative electrode active material layer, where the active material particles are not bound by a binder, allowing for flexibility and maintaining contact during deformation, with a stacked structure of positive electrode current collector, separator, negative electrode active material layer, and negative electrode current collector in an exterior cell container.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a thin film type cell using a specific film exterior body is used to achieve flexibility, then the cell can be deformed, but gaps or defects occur within the active material layer when significantly deformed, blocking conductive paths and reducing charge and discharge characteristics

Engineering Contradiction:

ImproveflexibilityVSAvoidcharge and discharge characteristics

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent uses a flexible film exterior body to enable cell deformation while maintaining structural integrity. The film exterior body is specifically designed to accommodate bending and deformation without causing gaps or defects in the active material layer, thus preserving charge and discharge characteristics while achieving flexibility.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The patent applies a coating layer to the active material layer before deformation occurs. This coating layer acts as a protective cushion that prevents gaps and defects from forming during deformation, maintaining the conductive paths and ensuring reliable charge and discharge characteristics even when the cell is significantly deformed.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Quantity of substance

If the amount of electrode active material is increased to achieve large capacity, then capacity increases, but the cell becomes less flexible and more prone to deformation-induced defects

Engineering Contradiction:

ImprovecapacityVSAvoidflexibility

Core Design Contradiction:

Quantity of substanceVSAdaptability or versatility

Solution Approach 1:

The flexible film exterior body allows the cell to maintain flexibility even with increased amounts of electrode active material. The film's flexibility compensates for the reduced flexibility caused by larger amounts of active material, enabling the cell to be deformed without causing gaps or defects in the active material layer.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The coating layer on the active material layer provides protective cushioning that prevents deformation-induced defects even when large amounts of active material are used. This allows the cell to achieve large capacity while maintaining flexibility and preventing gaps or defects during deformation.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Power

If a stack type bipolar cell structure is used to achieve high power density, then power density increases, but the active material layer becomes less flexible and more susceptible to gaps and defects under stress

Engineering Contradiction:

Improvepower densityVSAvoidmechanical durability

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The flexible film exterior body is designed to accommodate the stack type bipolar cell structure while maintaining flexibility. It allows the cell to be deformed without causing gaps or defects in the active material layer, thus preserving mechanical durability while achieving high power density through the stacked configuration.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The coating layer on the active material layer provides protective cushioning that prevents gaps and defects from forming during deformation. This is particularly important for stack type bipolar cells under stress, as it maintains the conductive paths and ensures mechanical durability while preserving the high power density achieved through stacking.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentUS10211462B2Lithium ion cell

Publication Date: 2019.02.19 SANYO CHEM IND LTD

AI summary

Provided is a lithium ion cell having a power generation part provided with a single cell obtained by stacking a positive electrode current collector, a positive electrode active material layer, a separator, a negative electrode active material layer, and a negative electrode current collector in the order, and an exterior cell container for accommodating the power generation part, in which the positive electrode active material layer is a non-bound material of a positive electrode active material particle, the negative electrode active material layer is a non-bound material of a negative electrode active material particle, and the single cell has flexibility.