Battery Pack Cover and Venting Layout for Thermal Propagation

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Solution Overview

Problem

Lithium secondary batteries are vulnerable to thermal events, which can lead to thermal propagation and potential accidents such as fire or explosion, especially in concentrated battery packs used in electric vehicles, due to the diffusion of venting gas.

Innovation Solution

A battery pack design featuring a case with protrusions and a pack cover that guides and accommodates venting gas, coupled with a venting device to quickly discharge gas outside, and partition walls to manage gas flow and suppress thermal propagation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a plurality of battery cells are concentrated in a narrow space to increase output and capacity, then productivity and energy density are improved, but thermal safety deteriorates due to increased risk of thermal chain reaction

Engineering Contradiction:
Improveoutput and capacityVSAvoidthermal safety
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The battery pack is divided into multiple battery modules, each module containing a plurality of battery cells. This segmentation allows thermal events to be contained within individual modules, preventing chain reactions across the entire battery pack while maintaining high density through optimized module arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A venting device is introduced as an intermediary component between battery modules. When thermal runaway occurs in one module, the venting device captures and directs venting gas away from adjacent modules, serving as a protective mediator that prevents thermal propagation while allowing safe pressure release.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Volume of moving object

If battery modules are arranged densely to reduce pack size, then volume efficiency is improved, but thermal propagation risk increases due to closer proximity of cells

Engineering Contradiction:
Improvepack sizeVSAvoidthermal propagation risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

Different regions of the battery pack are designed with different characteristics. High-density cell arrangements are used within individual modules to maximize energy density, while modules themselves are spaced with sufficient clearance and equipped with venting devices. This local differentiation allows dense packing overall while maintaining safety zones between modules.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The venting device acts as an intermediary safety mechanism that enables closer module spacing. By actively managing venting gas flow and directing it away from adjacent modules, the venting device allows modules to be positioned more closely together than would be safe without such intervention, thus reducing overall pack size while maintaining safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stress or pressure

If venting gas is allowed to diffuse freely during thermal events, then pressure relief is achieved, but thermal propagation occurs through gas diffusion to adjacent cells

Engineering Contradiction:
Improvepressure reliefVSAvoidthermal propagation
Core Design Contradiction:
Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The venting device serves as an intermediary component that intercepts venting gas before it can diffuse to adjacent battery modules. It captures the hot gas and directs it through a controlled path to a safe discharge location, thereby maintaining pressure relief functionality while preventing thermal propagation through gas diffusion.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The harmful venting gas is extracted from the battery module environment and redirected to a safe location. The venting device separates the venting gas from the battery modules, removing the propagation risk while preserving the necessary pressure relief function. This extraction prevents the gas from contacting adjacent cells.

Inventive Principle:
Principle #2Taking out (Extraction)

4Device complexity

If traditional battery pack design without dedicated venting structure is used, then device complexity is reduced, but thermal event control capability is insufficient

Engineering Contradiction:
Improvestructure complexityVSAvoidthermal event control
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The venting device is designed to perform multiple functions: pressure relief, thermal propagation prevention, and venting gas direction. By consolidating these functions into a single integrated component, the design achieves improved thermal safety without proportionally increasing overall system complexity. The same structure that provides pressure relief also serves as a thermal barrier and flow director.

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

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

Improves thermal safety by preventing gas dispersion and quickly discharging venting gas, thereby suppressing thermal events and reducing the risk of accidents.

Implementation Method 1

a pack cover that covers the upper surface of the case and has a flat plate portion and a protrusion protruding upward from the flat plate portion

Methodology Applied
Scientific EffectGas flow guidance:

Implementation Method 2

a venting device to quickly discharge the venting gas outside the case when a thermal event occurs

Methodology Applied
Scientific EffectPressure-driven gas discharge: Pressure Gradient

Implementation Method 3

partition walls to manage gas flow and suppress thermal propagation

Methodology Applied
Scientific EffectThermal barrier: Thermal Insulation

Data Source

PatentEP4675817A1Battery pack
Publication Date: 2026.01.07 LG ENERGY SOLUTION LTD
  • EP4675817A1 patent drawingFigure 1
  • EP4675817A1 patent drawingFigure 2
  • EP4675817A1 patent drawingFigure 3~4

AI summary

Disclosed is a battery pack. A battery pack according to an embodiment of the present disclosure may include a case having an open upper surface and providing an internal space; a plurality of battery cells accommodated inside the case; and a pack cover that covers the upper surface of the case and has a flat plate portion and a protrusion protruding upward from the flat plate portion.