Battery Module Strap Assembly for Cell Expansion Control

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Solution Overview

Problem

Lithium-ion batteries expand due to heating or overheating, affecting the operation of the battery module and surrounding equipment, and traditional modules held together by fasteners or welding do not effectively manage this expansion.

Innovation Solution

A lithium-ion battery module assembly featuring a cell stack with spacers, compression pads, and a strap assembly that includes a case with end caps and straps to maintain alignment and control expansion, using materials like anodized aluminum and silicone foam for thermal and electrical insulation, and tensile steel or polymer straps to manage expansion loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If traditional fasteners or welding are used to hold battery modules together, then structural strength is improved, but the ability to manage battery expansion is worsened

Engineering Contradiction:

Improvestructural strengthVSAvoidexpansion management capability

Core Design Contradiction:

StrengthVSAdaptability or versatility

Solution Approach 1:

The battery module is divided into individual cells with spacing between them, allowing each cell to expand independently while maintaining overall module integrity. The compression pads are segmented elements that distribute compression force across multiple contact points.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The module structure transitions from a rigid fixed configuration to a dynamic system that can accommodate dimensional changes. The spacing and compression mechanism allow the module to adapt its internal geometry in response to thermal expansion during operation.

Inventive Principle:

Principle #15Dynamics

2Productivity

If cells are placed close together to increase energy density, then productivity is improved, but the harmful effects of expansion are worsened

Engineering Contradiction:

Improveenergy densityVSAvoidexpansion impact on surrounding equipment

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

Compression pads are installed beforehand to preemptively manage expansion forces. These pads act as cushioning elements that absorb and distribute the stresses generated during battery operation, preventing damage before it occurs.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

Spacing elements and compression pads serve as intermediary components between adjacent cells and between cells and surrounding equipment. These intermediaries absorb expansion forces and prevent direct contact that would transmit harmful stresses to neighboring components.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If spacing elements are added to manage expansion, then expansion control is improved, but device complexity is worsened

Engineering Contradiction:

Improveexpansion controlVSAvoidmodule structure complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

Compression pads function as flexible elements that can deform under compression while maintaining contact with expanding cells. This flexibility allows the system to accommodate dimensional changes without requiring complex mechanical adjustment mechanisms.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The system manages expansion by changing the compression parameter applied to cells. By adjusting the pre-compression force on the pads, the module can accommodate varying expansion rates during different operational conditions without structural modification.

Inventive Principle:

Principle #35Parameter changes

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 assembly effectively manages lithium-ion battery expansion by maintaining alignment and controlling swelling forces, ensuring reliable operation and easy decommissioning of the battery module.

Implementation Method 1

using materials like anodized aluminum and silicone foam for thermal and electrical insulation

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

Methodology Applied

Scientific EffectCompression: Compression

Data Source

PatentUS20230318115A1Lithium-ion battery module strap assembly

Publication Date: 2023.10.05 STEWART & STEVENSON LLC

AI summary

An assembly includes a cell stack, the cell stack including a plurality of cells, the cells separated by cell spacers. The assembly also includes a compression pad at each end of the cell stack and a lithium-ion battery module strap assembly, the cell stack and compression pads positioned within the lithium-ion battery module strap assembly. The lithium-ion battery module strap assembly includes a case, the case including a bottom and two sides, end caps at each end of the case, and at least one strap, the strap positioned around the cell stack and connected to each end cap.