Vehicle Underbody Battery Tray With Integrated Refrigerant Cooling

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Solution Overview

Problem

Existing vehicle underbodies face challenges in accommodating large-capacity battery modules due to space constraints, and conventional cooling methods are inefficient, requiring additional space and components, which complicates assembly and reduces space efficiency.

Innovation Solution

An underbody structure that directly fastens to the vehicle body frame, incorporating a tray member with an open lower surface and a cover member featuring a refrigerant flow path, irregularities, and layers for enhanced cooling and rigidity, allowing for direct battery module integration and efficient space utilization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a large-capacity battery module is mounted on the vehicle body to increase driving distance or power, then the vehicle performance is improved, but the mounting space requirement increases making it difficult to find sufficient space

Engineering Contradiction:
Improvevehicle power and driving distanceVSAvoidmounting space
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent utilizes the vertical space under the vehicle body by creating a recessed receiving portion in the underbody structure. This allows the battery module to be mounted in the downward direction (vertical dimension) rather than only in the horizontal plane, effectively using three-dimensional space to accommodate large-capacity batteries without increasing the vehicle's footprint.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If a conventional air-cooling method is used for the battery module, then the cooling system is simple, but the cooling efficiency is insufficient and additional space for air flow paths is required

Engineering Contradiction:
Improvecooling system complexityVSAvoidbattery module temperature control efficiency
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent replaces the air-cooling method with a liquid cooling system by introducing a refrigerant flow path within the cover member. The liquid refrigerant circulates through the flow path to absorb heat from the battery module, providing superior cooling efficiency compared to air cooling while maintaining a relatively simple system structure.

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The patent integrates the refrigerant flow path directly into the cover member structure, merging the cooling system with the battery mounting structure. This combination eliminates the need for separate cooling components and additional space for air flow paths, achieving efficient cooling while simplifying the overall system.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the cover member is made as a simple flat plate, then the manufacturing is simple, but the structural rigidity is insufficient

Engineering Contradiction:
Improvecover member manufacturing simplicityVSAvoidcover member rigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent introduces irregularities (protrusions and recesses) into the cover member structure, creating a non-flat, curved surface geometry. This curved structure increases the moment of inertia and provides anti-vibration properties, significantly improving rigidity and strength while maintaining manufacturing feasibility through standard forming processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 solution provides sufficient space for battery modules, reduces assembly complexity, enhances cooling efficiency, and improves structural rigidity while minimizing space waste, facilitating easy repair and replacement.

Implementation Method 1

the cover member includes a flow path to circulate a refrigerant fluid

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 2

the irregularities of the cooling layer have protrusions that are formed along the flow path on a surface of the plate-shaped panel, wherein the irregularities of the cover layer have recessed portions that are formed on the surface of the plate-shaped panel to correspond to the protrusions of the cooling layer, and wherein the cooling layer and the cover layer have a structure in which the protrusions of the cooling layer are inserted into the recessed portions of the cover layer to be in close contact

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP3984865B1Underbody for vehicle
Publication Date: 2025.10.01 LG ENERGY SOLUTION LTD
  • EP3984865B1 patent drawingFigure 1
  • EP3984865B1 patent drawingFigure 2
  • EP3984865B1 patent drawingFigure 3

AI summary

Discussed is an underbody for a vehicle including a tray member fastened to a lower portion of a vehicle body frame and including a receiving portion having a structure with an open lower surface to accommodate a battery module; and a cover member to cover the open lower surface of the receiving portion, wherein the cover member includes a flow path to circulate a refrigerant fluid.