Composite Battery Enclosure for Cell-Stack Compression

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Solution Overview

Problem

Existing battery pressure management systems for ultralight aircraft are excessively heavy or complex, making them unsuitable for long-endurance solar-powered aircraft applications.

Innovation Solution

A lightweight battery pack assembly using a composite battery enclosure with primary fibers oriented parallel to the load path, applying predetermined pressure to a cell-stack through end-plates and strapping material, with distributed cell spacers for consistent compression and swelling management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If metallic or plastic structural methods are used to withstand the necessary applied load over time, then the battery pressure management is effective, but the weight becomes excessively heavy and the structure becomes overly complex

Engineering Contradiction:

Improvebattery pressure management effectivenessVSAvoidbattery assembly weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent employs carbon fiber reinforced polymer (CFRP) composite materials to replace traditional metallic or plastic structural methods. The composite battery enclosure is fabricated with carbon fiber reinforcement that provides the necessary mechanical strength to withstand compression loads while significantly reducing the overall weight and structural complexity compared to conventional materials

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The patent changes the material parameters by transitioning from isotropic metallic/plastic materials to anisotropic composite materials with tailored fiber orientations. The primary fibers are oriented parallel to the load path to optimize strength-to-weight ratio, enabling effective pressure management with reduced weight

Inventive Principle:

Principle #35Parameter changes

2Weight of moving object

If carbon fiber reinforcement is used in the battery enclosure, then the weight is reduced and structural efficiency is improved, but the manufacturing complexity increases

Engineering Contradiction:

Improvebattery enclosure weightVSAvoidcomposite enclosure fabrication

Core Design Contradiction:

Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent employs pre-preg carbon fiber sheets that are pre-impregnated with resin before being laid up in the desired configuration. This preliminary preparation of materials simplifies the manufacturing process by eliminating the need for complex resin mixing and application steps during assembly

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces traditional mechanical fastening and assembly methods with automated autoclave curing processes. The composite enclosure is fabricated in a single integrated piece using autoclave processing, which eliminates the need for multiple separate components and fasteners, thereby reducing overall manufacturing complexity despite the advanced material processing required

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 a lightweight, efficient pressure management system that maintains consistent compression on lithium polymer pouch cells, enhancing performance and cycle life while reducing weight and complexity, suitable for ultralight aircraft.

Implementation Method 1

a composite battery enclosure impregnated with a plurality of primary fibers that define a direction of the composite battery enclosure's tensile strength

Methodology Applied

Scientific EffectFiber tension: Tension

Implementation Method 2

the composite battery enclosure applies a predetermined pressure upon the cell-stack to compress the cell-stack in the direction of the composite battery enclosure's tensile strength

Methodology Applied

Scientific EffectComposite material structural properties: Composite Materials

Data Source

PatentUS10566647B2System, method, and apparatus for battery cell-stack compression

Publication Date: 2020.02.18 META PLATFORMS INC

AI summary

The present disclosure relates to the manufacture of battery packs/assemblies and more specifically, the manufacture of battery packs/assemblies for use in aircraft. A lightweight battery assembly with cell compression and/or pressure management system is disclosed herein. The battery assembly can employ a composite battery enclosure impregnated with a plurality of primary fibers that define a direction of the composite battery enclosure's tensile strength. A cell-stack can be positioned in the composite battery enclosure such that the composite battery enclosure applies a predetermined pressure upon the cell-stack to compress the cell-stack in the direction of the composite battery enclosure's tensile strength.