Battery Pack Pressure Relief Valve With Low-Resistance Gas Venting

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Solution Overview

Problem

Existing pressure relief valves for battery packs face challenges in maintaining high sealing capability when the port diameter is enlarged to accommodate increased gas release, leading to potential bending and seal failure of the sheet member.

Innovation Solution

A pressure relief valve design featuring a casing with a discharge hole, a valve mechanism, and a biasing portion that ensures the valve member closes the discharge hole, along with a cover and passage formation between the casing and cover to facilitate smooth gas discharge, while using fastening portions and seal members to enhance sealing and reduce flow resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the port diameter is enlarged to accommodate increased gas release, then the gas discharge capability is improved, but the sheet member may bend and adversely affect the seal of the pressure relief valve

Engineering Contradiction:
Improvegas discharge capabilityVSAvoidsealing capability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The pressure relief valve is divided into multiple functional components: a rigid body (casing) that maintains structural integrity, a separate sheet member (flexible diaphragm) that provides sealing, and a reinforcement plate that supports the sheet member. This segmentation allows each component to perform its specific function optimally without compromising the others.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure relief valve employs a composite structure combining a rigid casing material with a flexible sheet member material. The rigid casing provides structural stability and maintains the enlarged port geometry, while the flexible sheet member provides conformal sealing. This composite approach resolves the contradiction between maintaining large port dimensions for high gas discharge capability and ensuring adequate sealing performance.

Inventive Principle:
Principle #40Composite materials

2Area of stationary object

If the sheet member is enlarged to match the enlarged port, then the gas discharge area is increased, but the sheet member may bend and adversely affect the seal

Engineering Contradiction:
Improvedischarge areaVSAvoidsealing capability
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The sheet member is designed as a flexible diaphragm that can conform to the port geometry and provide effective sealing. The flexibility of this thin film component allows it to adapt to the enlarged port dimensions while maintaining sealing integrity, preventing the bending and seal failure that would occur with a rigid enlarged component.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

A reinforcement plate is introduced as an intermediary component between the sheet member and the port structure. This reinforcement plate provides structural support to the enlarged sheet member, preventing excessive bending while still allowing the sheet member to maintain contact with the port surface for effective sealing. The reinforcement plate mediates between the need for large discharge area and the need for sealing reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 maintains high sealing capability and reduces flow resistance, allowing for efficient gas discharge even with an enlarged port diameter, preventing seal failure and ensuring reliable operation.

Implementation Method 1

a biasing portion that biases the valve member to a closed position where the valve member closes the discharge hole

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

A passage is formed between the cover and the casing to release gas that is discharged from the discharge hole

Methodology Applied
Scientific EffectGas flow: Pressure Gradient

Data Source

PatentEP3979353B1Pressure relief valve for battery pack
Publication Date: 2025.07.30 NIFCO INC
  • EP3979353B1 patent drawingFigure 1
  • EP3979353B1 patent drawingFigure 2
  • EP3979353B1 patent drawingFigure 3

AI summary

A pressure relief valve for a battery pack is attached to a port formed in a pack case of a battery pack. The pressure relief valve has a casing including a discharge hole and a valve mechanism configured to open and close the discharge hole. The discharge hole is connected to the port when the pressure relief valve is attached to the port. The pressure relief valve includes a cover attached to the casing. A passage is formed between the cover and the casing to release gas that is discharged from the discharge hole. The valve mechanism includes a valve member configured to close the discharge hole and a biasing portion that biases the valve member to a closed position where the valve member closes the discharge hole.