Battery Pack Venting Channels Mitigate Thermal Runaway

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Solution Overview

Problem

Lithium ion battery cells can unexpectedly enter thermal runaway, causing flammable and corrosive gas release, which can lead to thermal propagation, pressure increases, and damage to seals and electrical contacts, posing risks of further cell failures and corrosion.

Innovation Solution

A ventilation assembly for battery cells featuring a matrix with lateral sides, channel assemblies, and outlets that direct venting gas outwardly, using low-strength, low-flammability plastic cover layers and lids to contain and divert corrosive and flammable materials away from electrical components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If battery cells are vented directly without channel assemblies, then venting speed is fast, but thermal propagation and corrosion damage to electrical contacts occur

Engineering Contradiction:

Improveprevention of thermal propagationVSAvoidstructure complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The venting system is segmented into multiple independent channel assemblies, each handling venting from specific battery cells. The channels are separated by walls that extend from lateral sides, creating isolated venting paths that prevent thermal propagation between adjacent cells while maintaining individual venting capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Channel assemblies act as intermediary structures between battery cells and the external environment. These channels provide a controlled pathway for venting gases, separating the hot corrosive venting materials from direct contact with electrical contacts and other battery cells, thus preventing damage and thermal propagation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If venting outlets are positioned close to battery cells, then venting efficiency is high, but damage to seals and structure occurs due to pressure and heat

Engineering Contradiction:

Improveventing efficiencyVSAvoidpressure and heat damage

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The venting outlets are positioned in three-dimensional space away from the battery cell array, extending laterally and vertically to redirect venting paths. This spatial arrangement allows efficient venting while maintaining safe distances from heat-sensitive components and structural elements.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The channel assemblies serve as intermediary conduits that extend the venting path away from battery cells. By routing venting through these channels before discharge to the external environment, the system maintains venting efficiency while protecting seals and structure from direct exposure to high pressure and heat.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Reliability

If multiple channel assemblies are added to handle venting from all lateral sides, then thermal propagation is prevented, but device complexity increases

Engineering Contradiction:

Improveisolation of venting between cellsVSAvoidnumber of channel assemblies

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The channel assembly design is universal and can be applied to all lateral sides of the battery pack. Each channel assembly performs the same multi-function: containing venting gases, directing flow away from cells, and preventing thermal propagation. This modular universal design simplifies the overall system compared to custom solutions for each side.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The channel assemblies are integrated within the battery pack structure, with channels nested within the housing and walls extending from lateral sides. This nesting approach allows multiple channel assemblies to coexist in a compact arrangement, reducing overall complexity while maintaining isolation between venting paths.

Inventive Principle:

Principle #7Nested doll (Nesting)

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

Effectively manages thermal runaway by safely venting gases and preventing damage to battery cell packs by routing venting gases outwards through one-way ports and channel assemblies, reducing the risk of thermal propagation and corrosion.

Implementation Method 1

Both the channel assembly and the outlet are configured to cause venting to propagate to and out of the outlet

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS11394079B2Battery cell pack thermal runaway mitigation

Publication Date: 2022.07.19 RIVIAN HOLDINGS LLC

AI summary

Systems and methods are described herein for venting battery cells in a battery cell pack assembly. An assembly includes a matrix configured to hold battery cells and channel assemblies that each include a venting channel for venting materials (e.g., flammable gas and conductive particulates) from the interior of the matrix to an outlet. Battery cells, particularly lithium ion battery cells, have a chance of entering a thermal runaway condition that causes the production of flammable gas. The assembly is configured such that battery cells are allowed to vent such flammable gas out of the assembly. A ventilation opening and channel in the assembly cause venting materials to be routed through and out of the assembly.