Battery Pack Venting Structure to Block Oxygen Re-Entry

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Solution Overview

Problem

Battery packs with multiple lithium secondary batteries face increased damage from fires and explosions due to rapid pressure changes during thermal events, leading to uncontrolled venting and oxygen introduction, which can ignite high-temperature gases and sparks.

Innovation Solution

A battery pack design featuring a module assembly with venting gas discharge openings and oxygen introduction preventing members that regulate the flow of venting gases and prevent oxygen re-introduction, using a pack cover and oxygen introduction preventing members to manage pressure and minimize oxygen ingress.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the number of lithium secondary batteries in battery modules is increased to achieve high capacity, then the capacity and power of the battery pack are improved, but the risk of fire and explosion increases due to thermal events

Engineering Contradiction:

Improvenumber of lithium secondary batteriesVSAvoidfire and explosion risk

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The battery pack is divided into multiple battery modules, each with its own venting gas discharge opening. This segmentation allows localized venting of thermal events in individual modules without affecting the entire pack, reducing the risk of widespread fire and explosion while maintaining high capacity through the increased number of batteries.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An oxygen introduction preventing member is introduced as an intermediary component between the venting gas discharge opening and the external environment. This member selectively prevents oxygen from entering the battery pack during negative pressure conditions while allowing venting gas to escape during thermal events, thereby reducing fire risk without compromising safety venting functionality.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Speed

If venting gas is discharged rapidly to relieve high initial venting pressure, then the pressure relief speed is improved, but negative pressure is generated due to rapid pressure decrease

Engineering Contradiction:

Improveventing gas discharge speedVSAvoidpressure stability

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The oxygen introduction preventing member is designed to dynamically respond to pressure changes within the battery pack. During high pressure thermal events, the member opens to allow venting gas discharge. As pressure decreases and negative pressure develops, the member automatically closes to prevent oxygen ingress, thus maintaining pressure stability while allowing rapid initial venting.

Inventive Principle:

Principle #15Dynamics

3Productivity

If the battery pack structure allows rapid venting gas discharge, then the venting efficiency is improved, but oxygen is reversely introduced when venting pressure decreases

Engineering Contradiction:

Improveventing efficiencyVSAvoidoxygen introduction

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The oxygen introduction preventing member acts as a selective intermediary that distinguishes between venting gas flow and oxygen ingress. It allows rapid venting gas discharge during thermal events while blocking oxygen from entering when pressure decreases, thus maintaining both venting efficiency and preventing harmful oxygen introduction.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The oxygen introduction preventing member helps maintain an inert atmosphere within the battery pack by preventing oxygen from entering during negative pressure conditions. This creates a protective environment that reduces the risk of fire even when venting gas is discharged rapidly, as the internal atmosphere remains oxygen-depleted.

Inventive Principle:

Principle #39Inert atmosphere (Inert environment)

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 design allows for controlled venting gas discharge, reducing negative pressure generation and oxygen introduction, thereby preventing fires and enhancing safety by maintaining stable pressure and minimizing oxygen exposure.

Implementation Method 1

configured to prevent oxygen from being reversely introduced after venting gas is discharged in an extension direction of the space

Methodology Applied

Scientific EffectPressure differential: Pressure Gradient

Data Source

PatentUS20240380069A1Battery pack, and ESS and vehicle including the battery pack

Publication Date: 2024.11.14 LG ENERGY SOLUTION LTD

AI summary

A battery pack includes a module assembly including a plurality of battery modules each including, on a side, a module opening through which venting gas is discharged, a pack cover facing the module opening and configured to cover the side of the module assembly, and an oxygen introduction preventing member located in a space formed between the module assembly and the pack cover and configured to prevent oxygen from being reversely introduced after venting gas is discharged in an extension direction of the space.