Corrugated Flexible Plate for Battery Module Fluid Expansion

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Solution Overview

Problem

Existing immersion cooled battery modules face issues with thermal expansion of the tempering fluid leading to pressure increases, which can damage the module, and require complex and costly solutions like balloons or bellows for pressure equalization.

Innovation Solution

A battery module design with a flexible plate covering openings in the housing, allowing the tempering fluid to expand into a space between the housing and the plate, which deforms to accommodate volume changes without significant pressure increases, using a corrugated shape to facilitate easy production and assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If battery modules are tightly packed to increase energy density, then space utilization is improved, but thermal expansion during charging causes deformation and potential damage

Engineering Contradiction:
Improvespace utilizationVSAvoidmodule deformation
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The battery module is segmented into multiple battery packs arranged in a matrix, with through-holes provided in the side walls between adjacent battery packs. This segmentation allows independent expansion compensation for each battery pack while maintaining overall tight packing, resolving the contradiction between space utilization and deformation prevention

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Electrolyte serves as an intermediary substance that flows through the through-holes to provide lubrication and expansion compensation. The electrolyte mediates between the battery packs and module housing, allowing thermal expansion without direct contact and potential damage, thus maintaining both tight packing and reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If expansion compensation structures are added to prevent deformation, then reliability is improved, but device complexity increases

Engineering Contradiction:
Improvedeformation preventionVSAvoidmodule structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The through-holes serve multiple functions: they provide electrolyte flow paths for expansion compensation, acts as lubrication channels, and maintain structural integrity. This multi-functionality achieves deformation prevention without adding separate dedicated expansion compensation structures, thus improving reliability while minimizing increased complexity

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If lubrication is applied to reduce friction during expansion, then ease of operation is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improveexpansion movementVSAvoidthrough-hole alignment
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The module housing is designed with integrated through-holes that maintain alignment through the housing structure itself rather than requiring separate precision components. The housing acts as a flexible container that can accommodate slight variations, reducing the need for high manufacturing precision while still enabling smooth expansion movement with electrolyte lubrication

Inventive Principle:
Principle #30Flexible shells and thin films

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 ensures efficient temperature control and homogeneous cooling of battery cells, allowing operation in any orientation and under mechanical stress without pressure buildup, while being cost-effective and easy to manufacture.

Implementation Method 1

the electrolyte may be provided with lubrication properties to reduce friction between the battery pack and the module housing

Methodology Applied
Scientific EffectLubrication: Lubrication

Implementation Method 2

the battery pack may expand during charging

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP4643408B1Battery module with thermal expansion compensation
Publication Date: 2026.04.22 WHITEMARK TECH GMBH
  • EP4643408B1 patent drawingFigure 1~2
  • EP4643408B1 patent drawingFigure 3~5
  • EP4643408B1 patent drawingFigure 6~7

AI summary

Provided is a battery module, comprising a housing (10), wherein at least one opening (11) is provided, forming a fluid connection between an inside of the housing and an outside of the housing; a plurality of battery cells (20) arranged in the housing; a tempering fluid included in the housing; a flexible plate (30) arranged on an outside surface of the housing and liquid-tightly covering the at least one opening, wherein the flexible plate is formed of a flexible material allowing for the tempering fluid to expand into a first space (S1) between the outside surface and the flexible plate, and the flexible plate exhibits, in an unstressed state, a corrugated shape.