Battery Pack Thermal Spread Inhibition Using Overhead Water Tank

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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 also maintaining energy density.

Innovation Solution

A battery pack design with a water tank above the battery cells, a heat sink, and a sealing member that melts to allow coolant injection directly into ignited cells, using a low-melting-point material to ensure rapid cooling and flame suppression.

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 cool the battery, but the water cannot be injected into the battery cell when the bag is disposed under the cell, limiting the fire extinguishing function

Engineering Contradiction:

Improvefire extinguishing functionVSAvoidposition flexibility of water tank

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent inverts the conventional approach by placing the water tank above the battery cells instead of below, and uses a sealing member that melts to open a passage for water to flow downward onto ignited cells, enabling effective fire suppression while maintaining structural integrity during normal operation

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a sealing member as an intermediary element that selectively blocks or allows water flow based on temperature conditions. This mediator enables the system to adapt to different operational states (normal vs. emergency) while maintaining a compact structure

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a fire extinguishing agent is disposed in the battery pack, then fire can be suppressed, but additional space is required reducing energy density

Engineering Contradiction:

Improvefire suppression capabilityVSAvoidenergy density

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses water, which is already present in the battery pack cooling system, as the fire suppression agent. This self-service approach eliminates the need for separate fire extinguishing agents, maintaining energy density while providing fire suppression capability through the same coolant infrastructure

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent makes the cooling water serve dual functions: normal thermal management during operation and fire suppression during emergencies. This multi-functionality eliminates the need for additional fire extinguishing agents, preserving energy density while ensuring safety

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Ease of manufacture

If water is used for cooling instead of fire extinguishing agents, then production costs are reduced, but the system must be designed to deliver water rapidly to ignited cells

Engineering Contradiction:

Improveproduction costVSAvoidwater delivery speed

Core Design Contradiction:

Ease of manufactureVSProductivity

Solution Approach 1:

The patent utilizes the phase transition (melting) of the sealing member material as a trigger mechanism. When the sealing member melts due to heat from ignited cells, it automatically opens the water passage, enabling rapid water delivery without complex active control systems, thus maintaining cost-effectiveness while ensuring rapid response

Inventive Principle:

Principle #36Phase transitions

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 enables rapid cooling and containment of ignited cells, preventing thermal runaway and flame spread, while minimizing weight and size increases, and reducing production costs by using water instead of fire extinguishing agents.

Implementation Method 1

a sealing member (220) added to one surface of the water tank (210), and made of a material that is melted by high-temperature gas or sparks discharged from a battery module

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 2

a water tank (210) located above the plurality of battery cells... capable of extinguishing ignition of a battery cell when the battery cell catches fire or explodes and preventing spread of flames to battery cells adjacent thereto

Methodology Applied

Scientific EffectHeat absorption: Absorption (physical)

Data Source

PatentUS12586864B2Battery pack including thermal spread inhibition structure

Publication Date: 2026.03.24 LG ENERGY SOLUTION LTD

AI summary

A battery pack includes a battery module configured to receive a plurality of battery cells, a battery pack case configured to receive two or more battery modules, and a heat sink located under the battery modules, wherein each of the battery modules includes a plurality of battery cells, a water tank located above the plurality of battery cells, and a module case configured to receive the plurality of battery cells and the water tank. When fire breaks out in the battery cell, it is possible to rapidly and accurately prevent spread of flames of the ignited battery cell.