Spring-Loaded Battery Module Structure for Cell Expansion Control

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Solution Overview

Problem

Existing battery modules face challenges in minimizing assembly tolerance between battery cells and effectively alleviating cell expansion, which are critical for compact configurations and safety.

Innovation Solution

A battery module design incorporating a mono frame with springs between cell stacks, plates, and a thermistor for temperature monitoring, along with a busbar frame, to minimize assembly tolerance and absorb cell expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If battery cells are tightly stacked to minimize assembly tolerance, then compact configuration is achieved, but cell expansion during charge-discharge cycles causes structural stress and potential failure

Engineering Contradiction:
Improvecell stack volumeVSAvoidstructural reliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by introducing elastic buffering elements (such as elastic sheets or springs) between battery cells before assembly. These elements are pre-installed to compensate for expansion forces that will occur during charge-discharge cycles, preventing structural stress and potential failure while maintaining compact configuration.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs parameter changes by using elastic buffering elements that dynamically change their physical parameters (compression, tension, deformation) in response to cell expansion. This allows the buffering structure to adapt to varying expansion forces during different charge-discharge states, maintaining both compactness and structural reliability.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If rigid fixation is used to minimize assembly tolerance, then compact configuration is achieved, but cell expansion causes increased stress on the fixation structure

Engineering Contradiction:
Improveassembly toleranceVSAvoidstress on fixation structure
Core Design Contradiction:
Manufacturing precisionVSStress or pressure

Solution Approach 1:

The patent applies dynamics by replacing rigid fixation with dynamic buffering structures that can adapt to cell expansion. The elastic buffering elements (sheets or springs) provide a dynamic response to expansion forces, allowing the fixation structure to maintain manufacturing precision while accommodating stress through elastic deformation rather than rigid resistance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs parameter changes by using elastic buffering elements that change their mechanical parameters (stiffness, deformation) in response to expansion forces. This allows the fixation structure to maintain tight assembly tolerance while dynamically adjusting to stress conditions, preventing stress concentration and structural failure.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If elastic buffering elements are added to accommodate cell expansion, then structural reliability is improved, but device complexity increases

Engineering Contradiction:
Improvestructural reliabilityVSAvoidbuffering structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies flexible shells and thin films by using elastic buffering sheets that conform to the cell geometry and provide uniform buffering across multiple cells. This approach achieves structural reliability through a simple, scalable design that avoids complex mechanical structures, as the thin elastic films can be easily installed between cells and automatically adapt to expansion forces.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent employs parameter changes by using elastic buffering elements with carefully selected material parameters (elastic modulus, thickness) that provide sufficient buffering capacity without requiring complex structures. By optimizing these parameters, the patent achieves structural reliability through simple elastic deformation rather than complex mechanical mechanisms.

Inventive Principle:
Principle #35Parameter changes

4Device complexity

If simple fixation without buffering is used, then device complexity is minimized, but cell expansion causes assembly tolerance issues

Engineering Contradiction:
Improvefixation structure complexityVSAvoidassembly tolerance
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent applies flexible shells and thin films by using elastic buffering sheets that maintain assembly tolerance through elastic deformation. These thin films are simple in structure but effective in maintaining precision, as they can be easily installed between cells and automatically compensate for expansion without requiring complex fixation mechanisms.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent applies beforehand cushioning by pre-installing elastic buffering elements that maintain assembly tolerance before expansion occurs. This simple pre-buffering approach prevents tolerance issues during operation without requiring complex active control mechanisms, as the elastic elements passively compensate for expansion forces.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 reduces assembly tolerance and effectively manages cell expansion, enhancing safety through spring-based fixation and temperature detection.

Implementation Method 1

a spring located between the first cell stack and the second cell stack

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3907811B1Battery module and battery pack including the same
Publication Date: 2025.12.10 LG ENERGY SOLUTION LTD
  • EP3907811B1 patent drawingFigure 1
  • EP3907811B1 patent drawingFigure 2
  • EP3907811B1 patent drawingFigure 3

AI summary

A battery module according to an embodiment of the present disclosure includes a first cell stack and a second cell stack including one or more battery cells, a mono frame receiving the first cell stack and the second cell stack. a spring located between the first cell stack and the second cell stack, a first plate located between the first cell stack and the spring, and a second plate located between the second cell stack and the spring, and the compression direction of the spring is parallel to the stack direction of the one or more battery cells.