Battery Cell Exterior Notch Venting for Internal Pressure Relief

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Solution Overview

Problem

Existing battery cells face challenges in controlling internal pressure, which can lead to swelling, heat generation, and potential explosions or fires during repeated charging and discharging cycles.

Innovation Solution

The battery cell design incorporates a groove-shaped notch portion on the inner surface of the exterior material, which is integrated with a protrusion portion on the outer surface. This design allows for controlled venting of internal pressure when it exceeds a certain threshold, thereby maintaining stability and preventing explosions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the internal pressure of the battery cell is increased during charging and discharging cycles, then the energy density and power output are improved, but the safety and stability deteriorate due to swelling, heat generation, and potential explosions

Engineering Contradiction:
Improvepower outputVSAvoidsafety and stability
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The notch portion is pre-formed in the exterior material before the battery cell is assembled and before any pressure buildup occurs. This preliminary structural feature is positioned and sized to ensure that when internal pressure reaches a critical threshold during charging/discharging, the notch will open at the predetermined location to release pressure, preventing catastrophic failure while allowing normal operation under lower pressures

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention converts the harmful effect of internal pressure buildup (which causes swelling, heat, and potential explosion) into a beneficial pressure-release mechanism. The notch portion is designed to open under excessive pressure, transforming the dangerous pressure accumulation into a controlled venting action that protects the battery cell while allowing the cell to operate at high power levels

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

2Reliability

If a venting mechanism is added to control internal pressure, then the safety is improved, but the device complexity increases

Engineering Contradiction:
ImprovesafetyVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The venting function is merged into the exterior material itself through the notch portion, rather than being a separate component. The notch is formed as an integral feature of the exterior material structure, combining the structural housing function with the pressure-release function in a single element, thereby improving safety without adding device complexity

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The notch portion serves itself as both a structural feature and a pressure-release mechanism. When internal pressure exceeds the threshold, the notch automatically opens without requiring external control systems, sensors, or additional mechanical components. The exterior material itself performs the venting action through its pre-designed geometric feature, eliminating the need for complex active pressure control systems

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If the notch portion is formed separately and then attached to the exterior material, then the manufacturing flexibility is improved, but the production efficiency and manufacturing cost deteriorate

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidproduction efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The notch portion is merged with the exterior material as an integral feature, formed in the same molding or fabrication process that creates the exterior material itself. This eliminates separate manufacturing steps for creating the notch and separate assembly steps for attaching it, thereby dramatically improving production efficiency while maintaining the ability to position the notch at various locations by simply adjusting the mold design

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The exterior material is designed to serve multiple functions: it provides structural housing, contains the electrode assembly, and incorporates the pressure-release function through the integrated notch portion. This multi-functional design eliminates the need for separate components and assembly operations, improving production efficiency while maintaining manufacturing flexibility through modular design approaches

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 proposed design effectively controls internal pressure, enhancing the stability and safety of battery cells by allowing for the safe discharge of gases and preventing damage from excessive pressure.

Implementation Method 1

When the internal pressure of the exterior material increases, the notch portion and the protrusion portion may be opened

Methodology Applied
Scientific EffectPressure-driven opening: Pressure Gradient

Data Source

PatentEP4521517A1Battery cell and manufacturing method of the same
Publication Date: 2025.03.12 SK ON CO LTD
  • EP4521517A1 patent drawingFigure 1
  • EP4521517A1 patent drawingFigure 2
  • EP4521517A1 patent drawingFigure 3

AI summary

A battery cell of the present disclosure includes an electrode assembly including a cathode, an anode, and a separator; an exterior material accommodating the electrode assembly therein; a notch portion recessed from an inner surface of the exterior material toward an outside and defined in the form of a groove; and a protrusion portion corresponding to the notch portion on an outer surface of the exterior material disposed in an opposite direction of the inner surface and protruding toward the outside.