Immersion-Cooled Battery Module for Dense Pack Thermal Runaway Control

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Solution Overview

Problem

Existing battery cooling technologies face challenges in maintaining effective cooling performance, preventing thermal runaway, and optimizing energy density due to space and weight constraints, particularly in densely packed battery modules and packs.

Innovation Solution

An immersion-cooled battery module design that directly contacts battery cells with a cooling liquid, utilizing insulating blocks and connection members to enhance cooling efficiency and integrate fire extinguishing capabilities, while minimizing module volume and weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If heat sink contacts only the lower edge portion of battery cells, then device complexity is reduced, but cooling performance deteriorates

Engineering Contradiction:
Improvecooling system structureVSAvoidbattery cell cooling performance
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent uses liquid cooling instead of solid heat sink contact. A cooling liquid circulates through channels formed by the case and battery cell arrangement, providing superior cooling performance without complex heat sink structures. The liquid flow paths are defined by the spatial relationship between battery cells and case walls, eliminating the need for separate heat sink components.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Temperature

If independent insulating oil pipes are provided for each battery cell stack case, then cooling performance is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvebattery cell cooling performanceVSAvoidcooling system structure
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the cooling functions of multiple battery cell stacks into a single integrated cooling system. The cooling liquid circulates through a common path that serves all battery cell stacks sequentially, eliminating the need for independent pipes for each stack. This reduces system complexity while maintaining effective cooling through the shared liquid cooling circuit.

Inventive Principle:
Principle #5Merging (Combining)

3Temperature

If independent insulating oil pipes are provided for each battery cell stack case, then cooling performance is improved, but weight and volume increase

Engineering Contradiction:
Improvebattery cell cooling performanceVSAvoidbattery pack weight
Core Design Contradiction:
TemperatureVSWeight of moving object

Solution Approach 1:

The patent combines multiple cooling circuits into a single integrated cooling loop that serves all battery cell stacks. This eliminates redundant piping, insulation materials, and associated components for each individual stack, significantly reducing the overall weight of the battery pack while maintaining effective thermal management across all cells.

Inventive Principle:
Principle #5Merging (Combining)

4Quantity of substance

If battery cells are densely placed in limited space, then energy density is improved, but thermal runaway prevention becomes difficult

Engineering Contradiction:
Improvebattery cell densityVSAvoidthermal runaway prevention
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent employs liquid cooling channels formed by the case and battery cell arrangement to provide intensive cooling to densely packed cells. The cooling liquid flows through paths that maximize heat extraction from each cell, preventing thermal runaway even in high-density configurations. The liquid cooling system provides superior heat removal capability compared to air cooling or heat sinks.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The cooling liquid acts as an intermediary between the battery cells and the external environment, facilitating efficient heat transfer. The liquid absorbs heat from the battery cells through the case walls and transports it to external cooling components, enabling thermal management of densely packed cells without direct thermal coupling between adjacent cells.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 cooling performance, prevents thermal runaway, reduces manufacturing costs, and enhances energy density by optimizing space utilization and integrating fire safety features.

Implementation Method 1

battery cells that can be cooled by direct contact with a cooling liquid

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

a moving passage for the cooling liquid to move along both ends of the battery assembly in the third direction

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP4418443B1Immersion-cooled battery module, and battery pack and vehicle comprising same
Publication Date: 2026.01.28 LG ENERGY SOLUTION LTD
  • EP4418443B1 patent drawingFigure 1
  • EP4418443B1 patent drawingFigure 2
  • EP4418443B1 patent drawingFigure 3

AI summary

An immersion-cooled battery module according to one aspect of the present disclosure includes a battery assembly including a plurality of battery units; a module case extending in a first direction, having an opening at least at one end in the first direction, and accommodating the battery assembly and a cooling liquid in an internal space connected to the opening; and a sealing cover airtightly covering the opening.