Battery Pack Staged Venting Structures for Pressure Management

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Solution Overview

Problem

Existing battery pack venting systems are inadequate in managing heat and pressure buildup, as they often rely on passive membranes that cannot vent heat rapidly or in large volumes, and movable valves may allow water ingress and fail to provide sufficient venting under extreme conditions.

Innovation Solution

The integration of multiple venting structures within the battery pack walls, including fixed plug valves, movable umbrella valves, and deformable vents, which allow for staged venting at different flow rates to manage heat and pressure effectively while preventing water ingress, with deformable vents mechanically failing to rapidly release excess pressure and heat.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If passive membranes are used for venting, then the battery pack maintains a sealed environment, but the venting capability is insufficient for rapid heat and pressure release

Engineering Contradiction:

Improvesealed environmentVSAvoidventing capability

Core Design Contradiction:

ReliabilityVSProductivity

Solution Approach 1:

The venting system is divided into multiple independent venting structures with different capabilities: passive membranes for low-flow sealed venting, movable valves for medium-flow controlled venting, and deformable vents for high-flow emergency venting. Each segment handles specific pressure/temperature ranges, resolving the contradiction between maintaining seal integrity and providing rapid venting capability.

Inventive Principle:

Principle #1Segmentation

2Productivity

If movable valves are used for venting, then the venting flow rate increases, but water ingress risk increases

Engineering Contradiction:

Improveventing flow rateVSAvoidwater ingress

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The movable valves utilize flexible membrane structures that can deform to open venting passages while maintaining fluid tight seals. The thin film membranes allow controlled movement for venting while preventing water ingress, resolving the contradiction between increased venting flow rate and water protection.

Inventive Principle:

Principle #30Flexible shells and thin films

3Productivity

If multiple venting structures are integrated, then the venting effectiveness improves, but the device complexity increases

Engineering Contradiction:

Improveventing effectivenessVSAvoidstructure integration

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

Multiple venting structures (passive membranes, movable valves, deformable vents) are merged into a single integrated battery pack enclosure wall system. They share common mounting structures and work together as a unified venting hierarchy, reducing overall system complexity while maintaining enhanced venting effectiveness.

Inventive Principle:

Principle #5Merging (Combining)

4Productivity

If deformable vents are designed to mechanically fail, then rapid pressure release is achieved, but the visual indicator function is lost after use

Engineering Contradiction:

Improvepressure release rateVSAvoidvisual indicator

Core Design Contradiction:

ProductivityVSLoss of information

Solution Approach 1:

The mechanical failure of the deformable vent is converted into a beneficial visual indicator function. The rupture or deformation of the vent structure after pressure release serves as a permanent visual marker that thermal or pressure events have occurred, transforming what appears to be a loss into a useful diagnostic feature.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution enables efficient venting of heat and pressure at various flow rates, addressing different thermal and pressure events without requiring battery pack servicing, while maintaining a sealed environment to prevent water and contaminant ingress, and provides visual indicators for thermal or pressure events.

Implementation Method 1

The enclosure is substantially sealed, such that a temperature increase causes excess pressure within the enclosure

Methodology Applied

Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

each of which is configured to vent from the enclosure to reduce the excess pressure

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS20230026302A1Battery pack venting

Publication Date: 2023.01.26 RIVIAN HOLDINGS LLC

AI summary

Systems are presented herein for venting pressure and heat from a battery pack. The system may include a set of walls encompassing a plurality of battery cells. Embedded in the walls may be a plurality of venting structures, which may be configured to release pressure and/or temperature building within the battery pack. The plurality of venting structures may include a plurality of valves, including a fixed valve configured to vent at a first flow rate, and a movable valve configured to vent at a second flow rate exceeding the first flow rate. The plurality of venting structures may also include a deformable vent structure configured to physically deform to provide a third flow rate exceeding the second flow rate.