Compressed Pouch Cell Battery with Thermal Isolation and Heat Sinks

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Solution Overview

Problem

Batteries face thermal runaway issues due to heat propagation from failing cells, leading to catastrophic failures of adjacent cells, and existing solutions either compromise on performance or do not adequately address heat dissipation during normal operation.

Innovation Solution

A battery design featuring a metal can with compressed pouch cells, layered insulation, and thermal conductors with fins that apply pressure to cells, preventing heat spread and enhancing heat dissipation through the use of aerogel insulation and thermally conductive materials, while vent holes and intumescent paint further mitigate thermal runaway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal insulators are used to prevent heat propagation between cells, then thermal runaway prevention is improved, but heat dissipation during normal operation deteriorates

Engineering Contradiction:
Improvethermal runaway preventionVSAvoidheat dissipation
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The patent divides the thermal management system into two distinct segments: thermal insulators positioned between adjacent cells to prevent heat propagation during thermal runaway, and thermal conductors (heat sinks) attached to individual cells to facilitate heat dissipation during normal operation. This segmentation allows each component to perform its specialized function without interfering with the other.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces thermal conductors as intermediary components that act as heat sinks between the battery cells and the surrounding environment. These intermediaries absorb excess heat from individual cells during normal operation and transfer it to the environment, while the thermal insulators between cells prevent heat from propagating to adjacent cells during thermal runaway events.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of moving object

If compression force is applied to extend cycle life, then durability is improved, but structural integrity under stress deteriorates

Engineering Contradiction:
Improvecycle lifeVSAvoidstructural integrity
Core Design Contradiction:
Duration of action of moving objectVSStrength

Solution Approach 1:

The patent applies compression force locally and uniformly to each individual cell within the battery pack, rather than applying uneven stress to the entire structure. This localized compression extends the cycle life of each cell by maintaining optimal contact and electrical connection, while the distributed nature of the compression across multiple cells prevents any single point from experiencing excessive stress that would compromise overall structural integrity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent incorporates thermal insulators and structural supports as cushioning elements that are pre-positioned within the battery pack design. These elements provide mechanical support and stress distribution before failure can occur, allowing the compression force to be applied safely over extended periods to extend cycle life without compromising structural integrity during abnormal stress conditions.

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

3Temperature

If thermal conductors are added to dissipate heat, then heat dissipation is improved, but device complexity increases

Engineering Contradiction:
Improveheat dissipationVSAvoidstructure complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The patent merges the functions of thermal management and structural support into a single integrated design. The thermal conductors (heat sinks) are attached directly to the battery cells and serve dual purposes: dissipating heat during normal operation and providing structural support within the battery pack. This merging eliminates the need for separate structural framework components, thereby reducing overall device complexity while maintaining effective heat dissipation.

Inventive Principle:
Principle #5Merging (Combining)

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 effectively prevents thermal runaway by slowing heat propagation between cells, extends cycle life through applied pressure, and ensures reliable operation by maintaining structural integrity and heat dissipation capabilities.

Implementation Method 1

Each cell is surrounded by a layer of insulation to prevent heat from one cell from propagating to another cell

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

thermal conductors with fins that apply pressure to cells, preventing heat spread and enhancing heat dissipation through the use of aerogel insulation and thermally conductive materials

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

thermal conductors with fins that apply pressure to cells, preventing heat spread and enhancing heat dissipation

Methodology Applied
Scientific EffectConvection: Convection

Implementation Method 4

at least two opposing sides of the metal can are biased inward (e.g., by compressing at least two sides of the metal can with the stacked layers inside) against the cells to provide compression. The cells are stacked with layers of insulation so that if one cell fails catastrophically, the released heat will not cause a neighboring cell to also fail.

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 5

The lid is painted with intumescent paint

Methodology Applied
Scientific EffectIntumescent materials: Intumescent Materials

Data Source

PatentEP3497731B1Battery with compression and features for the prevention of thermal runaway propagation
Publication Date: 2024.07.31 WISK AERO LLC
  • EP3497731B1 patent drawingFigure 1
  • EP3497731B1 patent drawingFigure 2
  • EP3497731B1 patent drawingFigure 3

AI summary

A battery includes a metal can having a bottom, a top opening, and four sides. The battery also includes a plurality of cells stacked inside the metal can, wherein at least two opposing sides of the four sides of the metal can are biased inward against the plurality of cells to provide compression.