Battery Pack Venting Assembly With Re-Sealing Piston Control

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Solution Overview

Problem

Existing battery pack venting devices are disposable and cannot be reused, fail to accurately detect pressure abnormalities, and do not maintain a sealed state after venting, posing risks of deformation and damage.

Innovation Solution

A reversible venting device with a piston assembly, magnet unit, and sensing units that allow for controlled gas discharge and re-sealing, along with electromagnetic force to manage internal pressure and detect venting failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a burst disc or gore vent is applied to vent the battery pack, then the internal pressure can be lowered to atmospheric pressure, but the venting element cannot be reused and must be replaced after opening

Engineering Contradiction:
Improveventing functionVSAvoiddevice replacement
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The patent applies a dynamic sealing mechanism where a piston moves between a sealed position (blocking the venting passage) and a venting position (opening the passage). This dynamic structure allows the venting device to be reused multiple times by returning to the sealed position after venting, eliminating the need for replacement after single-use venting events.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent recovers the sealing function after venting by automatically closing the venting passage through the piston's return movement. This recovery mechanism allows the same venting device to be reused for subsequent venting events, converting a disposable element into a reusable component.

Inventive Principle:
Principle #34Discarding and recovering

2Reliability

If a disposable venting element is used, then the internal pressure can be released, but it is impossible to determine whether an abnormality occurs at the battery cells

Engineering Contradiction:
Improvepressure releaseVSAvoidabnormality detection
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent incorporates a sensing unit that detects the piston's position and provides feedback information about venting events. This feedback mechanism enables the system to distinguish between normal pressure changes and abnormal venting events caused by battery cell issues, allowing for accurate abnormality detection and appropriate response actions.

Inventive Principle:
Principle #23Feedback

3Reliability

If the battery pack is manufactured to maintain a sealed state, then protection is provided against pressure rise, but deformation and damage occur when internal pressure rises abnormally high

Engineering Contradiction:
Improvesealed stateVSAvoidpressure damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary anti-action by providing a pressure relief mechanism (venting passage activated by piston movement) that prevents the harmful effect of excessive internal pressure before damage can occur. The sensing unit and electromagnetic coil activate the venting function in advance when abnormal pressure is detected, protecting the battery pack from deformation and damage.

Inventive Principle:
Principle #9Preliminary anti-action

4Stress or pressure

If venting is performed to lower internal pressure, then pressure equalization is achieved, but the battery pack loses its sealed state

Engineering Contradiction:
Improveinternal pressureVSAvoidsealed state
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The patent uses a dynamic piston mechanism that can transition between sealed and venting states. After pressure equalization, the piston returns to the sealed position, automatically restoring the sealed state without requiring manual intervention or device replacement, thus maintaining both pressure control and sealing reliability.

Inventive Principle:
Principle #15Dynamics

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

Enables quick gas discharge and re-sealing, allows for accurate detection of pressure abnormalities, and ensures the battery pack remains sealed, reducing the risk of deformation and damage.

Implementation Method 1

a magnet unit installed in the cylinder block and configured to restrict upward movement of the piston assembly by a magnetic force so that the communication between the venting gas flow path and the inner space of the battery pack is blocked

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 2

an electromagnetic coil configured to surround a part of the piston assembly

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnetic Induction

Data Source

PatentEP4270621B1Battery pack assembly comprising venting device and vehicle including battery pack assembly
Publication Date: 2025.10.15 LG ENERGY SOLUTION LTD
  • EP4270621B1 patent drawingFigure 1
  • EP4270621B1 patent drawingFigure 2
  • EP4270621B1 patent drawingFigure 3

AI summary

Disclosed is a venting device, which is provided at one side of a battery pack to discharge a venting gas generated in an inner space of the battery pack to the outside, and the venting device includes a cylinder block configured to communicate with the inside of the battery pack and have a venting gas flow path for discharging the venting gas to the outside; a piston assembly configured to move upward along an extension direction of the cylinder block by receiving a force caused by the increase of the internal pressure of the battery pack so that the inner space of the battery pack communicates with the venting gas flow path; and a magnet unit installed in the cylinder block and configured to restrict upward movement of the piston assembly by a magnetic force so that the communication between the venting gas flow path and the inner space of the battery pack is blocked.