Heat-Shrink Insulating Sleeve for Electrode Laminate Stability

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Solution Overview

Problem

Existing secondary battery technologies face issues with lamination dislocation between positive and negative electrodes, leading to reduced energy density and durability due to uneven stress distribution and deformation during impact or temperature changes.

Innovation Solution

A battery cell design utilizing a tube-shaped insulating member with controlled heat shrinkage properties to uniformly hold the electrode laminate, ensuring uniform distance between electrodes and preventing deformation, by aligning the main shrinkage direction with the lamination direction and applying a uniform compressive stress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If a porous sheet is wound around the laminate to hold it, then the laminate is held together, but a level difference arises at the winding end part causing stress distribution and durability degradation

Engineering Contradiction:

Improvelaminate holdingVSAvoiddurability

Core Design Contradiction:

Stability of the object's compositionVSReliability

Solution Approach 1:

The patent uses a heat-shrinkable film to wrap around the electrode laminate, forming a flexible shell that holds the laminate uniformly. The film is heated to shrink and conform to the laminate shape, eliminating level differences at winding ends and distributing stress evenly, thus improving durability while maintaining laminate stability.

Inventive Principle:

Principle #30Flexible shells and thin films

2Stability of the object's composition

If the dimensional difference between positive and negative electrodes is increased to prevent electrodeposition, then lamination dislocation is prevented, but energy density decreases

Engineering Contradiction:

Improvelamination dislocation preventionVSAvoidenergy density

Core Design Contradiction:

Stability of the object's compositionVSQuantity of substance

Solution Approach 1:

The patent changes the physical state of the holding mechanism from rigid (wound porous sheet) to thermally responsive (heat-shrinkable film). By controlling the heat shrinkage parameters, the film adapts to the actual dimensions of the laminate, providing uniform holding force without requiring excessive dimensional differences between electrodes, thus maintaining energy density while preventing lamination dislocation.

Inventive Principle:

Principle #35Parameter changes

3Stability of the object's composition

If only the laminate surface in heat shrinkable film is shrunk by heating, then lamination dislocation is prevented, but the unheated surface shrinks due to temperature rise causing uneven electrode distance

Engineering Contradiction:

Improvelaminate holding uniformityVSAvoidelectrode distance uniformity

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

The patent applies preliminary heating to the entire heat-shrinkable film before final assembly, causing uniform shrinkage of all surfaces including both heated and unheated areas. This preliminary action ensures that when the battery operates and temperature rises, all surfaces shrink uniformly, maintaining consistent electrode distance and preventing deformation.

Inventive Principle:

Principle #10Preliminary action

4Stability of the object's composition

If a sheet-shaped body is wound around the laminate to hold it, then the laminate is held, but stress distribution is generated in the laminate

Engineering Contradiction:

Improvelaminate holdingVSAvoidstress distribution

Core Design Contradiction:

Stability of the object's compositionVSStress or pressure

Solution Approach 1:

The patent utilizes the phase transition of the heat-shrinkable film from a relaxed state to a shrunk state through thermal heating. This phase transition allows the film to gradually conform to the laminate shape, distributing stress uniformly across the entire laminate surface rather than concentrating stress at specific points, thus improving both holding stability and reducing stress distribution.

Inventive Principle:

Principle #36Phase transitions

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 prevents lamination dislocation and enhances electrode durability, maintaining energy density and structural integrity under external forces and temperature variations.

Implementation Method 1

the insulating member is heat-shrinkable mainly in a direction parallel to the lamination direction of the electrode laminate

Methodology Applied

Scientific EffectHeat shrinkage: Thermal Contraction

Data Source

PatentUS12620629B2Battery cell and manufacturing method of the same

Publication Date: 2026.05.05 HONDA MOTOR CO LTD

AI summary

A battery cell capable of holding an electrode laminate uniformly and improving lamination dislocation as well as the durability of an electrode is provided. A battery cell includes an electrode laminate in which a positive electrode and a negative electrode are alternately laminated via an electrolyte layer. The battery cell includes a tube-shaped insulating member that holds the electrode laminate, and the insulating member is heat-shrinkable mainly in a direction parallel to the lamination direction of the electrode laminate. The insulating member preferably has a heat shrinkage percentage of to −5% to 5% in a direction in which the current collector tab of the electrode laminate extends.