Battery Pack Flame-Retardant Paper Wrap for Flame Leakage Suppression

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Solution Overview

Problem

Existing battery packs face challenges in enhancing safety without using expensive flame-retardant fire-resistant caps, which are costly and increase weight and size due to resin molding processes.

Innovation Solution

A battery pack design that incorporates flame-retardant paper folded to cover secondary battery cells from the end face to the side face, forming a multilayered structure to prevent flame leakage, using inexpensive materials and flexible folding methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fire-resistant cap made of flame-retardant resin is used to cover the secondary battery cell, then flame leakage is prevented and safety is improved, but manufacturing cost increases due to expensive mold and molding processes

Engineering Contradiction:
Improveflame leakage preventionVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent replaces the expensive fire-resistant resin cap with a disposable flame-retardant paper wrap that can be easily applied and discarded after use, significantly reducing manufacturing costs while maintaining flame leakage prevention functionality

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent uses a flexible flame-retardant paper wrap instead of a rigid resin cap, allowing the wrapping material to conform to the battery cell shape and provide effective flame protection through its flame-retardant properties

Inventive Principle:
Principle #30Flexible shells and thin films

2Reliability

If a fire-resistant cap made of flame-retardant resin is used to cover the secondary battery cell, then flame leakage is prevented and safety is improved, but the weight and size of the battery pack increase

Engineering Contradiction:
Improveflame leakage preventionVSAvoidbattery pack weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent employs a thin flame-retardant paper wrap that provides adequate flame protection with minimal added weight, compared to the bulky resin cap that would significantly increase battery pack weight

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent transitions from a three-dimensional rigid cap structure to a two-dimensional wrapped paper configuration, reducing material usage and overall weight while maintaining protective functionality

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Reliability

If the flame-retardant paper is folded to cover the secondary battery cell from end face to side face with partial double-overlap, then flame leakage is suppressed effectively, but the manufacturing process complexity increases

Engineering Contradiction:
Improveflame leakage suppressionVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent divides the flame-retardant paper into specific folding sections with defined overlap regions, allowing systematic assembly that ensures complete coverage while maintaining manageable manufacturing complexity through standardized folding patterns

Inventive Principle:
Principle #1Segmentation

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 suppresses flame leakage from battery packs, enhancing safety and reducing costs by utilizing affordable flame-retardant paper, while maintaining compactness and weight efficiency.

Implementation Method 1

a flame-retardant material interposed between the outer case and an end face of a secondary battery cell. The flame-retardant material is provided so that flame-retardant paper is folded to cover the secondary battery cell from an end face to a side face

Methodology Applied
Scientific EffectFlame retardation:

Data Source

PatentEP4683065A1Battery pack and method for manufacturing same
Publication Date: 2026.01.21 PANASONIC ENERGY CO LTD
  • EP4683065A1 patent drawingFigure 1
  • EP4683065A1 patent drawingFigure 2
  • EP4683065A1 patent drawingFigure 3~4

AI summary

Provided are a battery pack and a manufacturing method therefor, in which safety is enhanced without using an expensive flame-retardant fire-resistant cap. A battery pack 100 includes one or more secondary battery cells 1, an outer case 10 that stores the one or more secondary battery cells 1, and a flame-retardant material 30 interposed between the outer case 10 and an end face of a secondary battery cell 1. The flame-retardant material 30 is provided so that flame-retardant paper 31 is folded to cover the secondary battery cell 1 from an end face to a side face thereof and partially double-overlap at least the side face. This configuration in which the secondary battery cells 1 are covered by folding the inexpensive flame-retardant paper 31 can suppress leakage of flames to the outside of the outer case 10 even in the event that the secondary battery cells 1 catch fire.