Battery Pack Thermal Spread Inhibition With Melt-Open Coolant Injection

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Solution Overview

Problem

Existing battery pack technologies struggle to effectively extinguish ignited battery cells and prevent the spread of flames without increasing size, weight, or requiring additional space, while maintaining energy density.

Innovation Solution

A battery pack design featuring a water tank above battery module housings with a heat sink below, a flow path for coolant, and a sealing member that melts to allow coolant injection into ignited cells, minimizing thermal runaway and flame spread.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bag containing water is used with low melting point material, then the bag melts and discharges water to the battery when temperature increases, but the water cannot be injected into the battery cell when the bag is disposed under the battery cell, limiting the bag to specific directions only

Engineering Contradiction:

Improvefire extinguishing functionVSAvoidinstallation direction flexibility

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The sealing member is divided into a first sealing member and a second sealing member positioned at opposite ends of the through-hole. This segmentation allows the sealing members to melt and open the through-hole in any orientation, enabling the battery pack to function effectively regardless of installation direction.

Inventive Principle:

Principle #1Segmentation

2Reliability

If a fire extinguishing agent is disposed inside or outside the battery module, then heat transfer between battery cells is interrupted or the ignited cell is cooled, but the fire extinguishing agent is not exactly spread to the point at which fire breaks out since it is disposed in an empty space

Engineering Contradiction:

Improvefire extinguishing functionVSAvoidcoolant delivery accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

A coolant guide member is introduced as an intermediary component that channels the coolant from the water tank directly to the battery cell. This ensures the coolant is delivered precisely to the point of ignition rather than being dispersed in empty space, improving fire extinguishing effectiveness.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If facilities and space for a watering device are required, then fire can be extinguished, but facilities and space are required and fire may spread due to time difference between sensing time and watering time

Engineering Contradiction:

Improvefire extinguishing capabilityVSAvoidresponse time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The sealing member automatically melts and opens the through-hole when exposed to high temperature from battery thermal runaway, triggering coolant discharge without requiring external sensing or control systems. This self-activating mechanism eliminates response time delays associated with sensing and actuation systems.

Inventive Principle:

Principle #25Self-service

4Reliability

If the entirety of the bag is made of material that has a low melting point, then the bag melts and water is discharged when battery temperature increases, but the water is not discharged from a specific portion but the entirety of water is discharged while the bag is melted

Engineering Contradiction:

Improvethermal response functionVSAvoidcontrolled water discharge

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The sealing member is positioned locally at the through-hole rather than making the entire water tank from low melting point material. This localized approach allows controlled discharge of coolant through the through-hole when the sealing member melts, preventing uncontrolled discharge from the entire tank structure.

Inventive Principle:

Principle #3Local quality

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

Rapid cooling and extinguishing of ignited cells, preventing thermal runaway, and maintaining pack size and energy density without additional space or weight, while reducing production costs.

Implementation Method 1

a sealing member (220) added to the through-hole, when fire breaks out in the battery cell, the sealing member (220) melts to open the through-hole (230)

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

coolant received in the water tank (200) is introduced into the battery cell (120) through the through-hole (230), thereby rapidly cooling the ignited battery cell (120)

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentUS12609376B2Battery pack including thermal spread inhibition structure

Publication Date: 2026.04.21 LG ENERGY SOLUTION LTD

AI summary

A battery pack includes a battery module housing configured to receive a plurality of battery cells, a battery pack case configured to receive one or more of battery module housings, a water tank located above the battery module housings, and a heat sink located under the battery module housings. At least a portion of the surface of the battery module housing that faces the water tank is open, whereby, when fire breaks out in the battery cell, it is possible to rapidly and accurately prevent spread of flames of the ignited battery cell.