PCB Flame Barrier Between Battery Modules to Limit Thermal Runaway

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Solution Overview

Problem

Existing battery packs face issues with flame propagation and chain thermal runaway between battery modules, requiring a solution that prevents fire spread and simplifies assembly while reducing costs.

Innovation Solution

A battery pack design featuring cylindrical battery cells, a pack case, and a flame propagation prevention member using a printed circuit board (PCB) with electric connection pins to connect battery modules, allowing for simple assembly and replacement of components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If battery modules are connected using conventional methods, then electrical connection is achieved, but flame propagation between modules cannot be prevented

Engineering Contradiction:
Improveflame propagation preventionVSAvoidassembly structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The PCB serves dual functions: it provides electrical connection between battery modules through its conductive traces and connection pins, while simultaneously acting as a flame propagation prevention barrier due to its flame-retardant material properties. This multi-functionality eliminates the need for separate connection components and fire prevention barriers, thereby reducing assembly complexity while ensuring reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The PCB is made from flame-retardant composite materials (such as FR-4) that combine electrical conductivity with fire resistance properties. This composite material approach allows the single component to provide both electrical connection and flame propagation prevention, resolving the contradiction between reliability and device complexity.

Inventive Principle:
Principle #40Composite materials

2Reliability

If multiple components are used for electrical connection and flame prevention, then reliability is improved, but manufacturing cost and process complexity increase

Engineering Contradiction:
Improvebattery module connection reliabilityVSAvoidmanufacturing process simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention merges the electrical connection function and flame propagation prevention function into a single integrated component (the PCB). Instead of using separate connection wires or busbars combined with separate fire-resistant barriers, the PCB combines both functions, simplifying the manufacturing process and reducing the number of assembly steps while maintaining high reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The PCB is designed as a universal component that performs multiple functions: electrical connection, mechanical support, and flame propagation prevention. This multi-functionality reduces the total component count and simplifies manufacturing processes, directly addressing the ease of manufacture parameter while preserving reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Reliability

If complex assembly structures are used to prevent flame propagation, then safety is improved, but ease of repair and component replacement is reduced

Engineering Contradiction:
Improvechain thermal runaway preventionVSAvoidcomponent replacement ease
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The PCB's multi-functional design allows it to provide chain thermal runaway prevention through its flame-retardant properties while maintaining simple, standardized connection interfaces. The use pins and standard PCB mounting holes enable tools to be easily removed and replaced without complex disassembly procedures, thus preserving ease of repair while ensuring safety.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The battery pack is divided into modular battery modules, each with its own PCB. This segmentation allows individual modules to be independently replaced if needed, and the standardized PCB design within each module simplifies the replacement process. The flame propagation prevention is achieved at the module level through each PCB, maintaining safety while enabling easy repair.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4718619A1Battery pack, and electric bicycle and vehicle including same
Publication Date: 2026.04.01 LG ENERGY SOLUTION LTD
  • EP4718619A1 patent drawingFigure 1
  • EP4718619A1 patent drawingFigure 2
  • EP4718619A1 patent drawingFigure 3

AI summary

Disclosed is a battery pack, and an electric bicycle and a vehicle including the same. The battery pack includes a plurality of battery modules having a plurality of cylindrical battery cells; a pack case configured to accommodate the plurality of battery modules; and a flame propagation prevention member arranged between a first battery module among the plurality of battery modules and a second battery module adjacent to the first battery module to prevent propagation of a flame generated from any one battery module, wherein the flame propagation prevention member is configured to electrically connect the first battery module and the second battery module.