Dual Trap Battery Venting System for Spark and Electrolyte Containment

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Solution Overview

Problem

Existing battery packs face challenges in preventing the propagation of thermal runaway, which can occur due to the scattering of sparks and electrolyte solution when a gas vent valve opens, potentially leading to unsafe conditions within the battery pack.

Innovation Solution

The implementation of a dual trap system, where the first trap is a mesh material with an adjustable aperture ratio to capture sparks and the second trap is a non-flammable material like spongy, mineral wool, or fibrous material, positioned further outward to contain the electrolyte solution, both designed to prevent the scattering of sparks and electrolyte solution when the gas vent valve opens.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a gas vent valve is provided on the battery case to release gas, then gas pressure relief is improved, but sparks and electrolyte solution may scatter outward causing safety hazards

Engineering Contradiction:

Improvegas pressureVSAvoidscattering of sparks and electrolyte solution

Core Design Contradiction:

Stress or pressureVSObject-affected harmful factors

Solution Approach 1:

A mesh material is introduced as an intermediary component between the gas vent valve and the external environment. This mesh material allows gas to pass through while intercepting and containing sparks and electrolyte solution that would otherwise scatter outward, thus resolving the contradiction between pressure relief and safety hazards

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The safety mechanism is segmented into multiple functional layers: the gas vent valve for pressure relief, the mesh material for spark and droplet containment, and the non-flammable liquid retaining material for electrolyte absorption. This segmentation allows each component to address specific aspects of the problem independently

Inventive Principle:

Principle #1Segmentation

2Object-affected harmful factors

If a mesh material is used to trap sparks, then spark containment is improved, but gas flow resistance increases

Engineering Contradiction:

Improvespark containmentVSAvoidgas flow rate

Core Design Contradiction:

Object-affected harmful factorsVSSpeed

Solution Approach 1:

A mesh material with controlled porosity is used to trap sparks while maintaining adequate gas flow. The porous structure allows gas molecules to pass through while the physical mesh architecture intercepts larger particles like sparks and electrolyte droplets, balancing containment effectiveness with flow performance

Inventive Principle:

Principle #31Porous materials

3Reliability

If non-flammable liquid retaining material is added to contain electrolyte solution, then fire safety is improved, but device complexity increases

Engineering Contradiction:

Improvefire safetyVSAvoidtrap system structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Different materials with specific properties are applied at different locations: mesh material for spark containment and non-flammable liquid retaining material for electrolyte absorption. Each material is strategically placed where it provides the most effective local protection, optimizing fire safety without requiring uniform complex structures throughout

Inventive Principle:

Principle #3Local quality

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

This dual trap system effectively reduces the risk of thermal runaway propagation by containing sparks and electrolyte solution, enhancing safety within the battery pack by allowing controlled gas discharge while preventing internal spraying and ignition.

Implementation Method 1

The first trap (12) includes a mesh material disposed outside the battery case (11a) so as to oppose and cover the gas vent valve (11a1)

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 2

The second trap (13) includes a liquid retaining material made of a non-flammable material and disposed further outward of the first trap (12) so as to oppose and cover the gas vent valve (11a1)

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 3

The second trap (13) includes a liquid retaining material made of a non-flammable material

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS11502371B2Battery unit, battery module, and battery pack

Publication Date: 2022.11.15 TOYOTA JIDOSHA KK

AI summary

A battery unit includes a secondary battery, a first trap, and a second trap. The secondary battery includes a battery case provided with a gas vent valve, and an electrolyte solution enclosed in the battery case. The first trap includes a mesh material disposed outside the battery case so as to oppose and cover the gas vent valve. The second trap includes a liquid retaining material made of a non-flammable material and disposed further outward of the first trap so as to oppose and cover the gas vent valve.