Battery Cell Exterior With Localized Venting for Swelling Pressure
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Solution Overview
Problem
Lithium secondary batteries face a swelling phenomenon during repeated charging and discharging, leading to increased internal pressure, heat generation, and potential explosion or fire, necessitating improved internal pressure control and stability.
Innovation Solution
A battery cell design featuring an exterior material with a variable tensile strength, including a notch portion with lower tensile strength than the surrounding region, allows for controlled internal pressure adjustment by opening the notch portion when internal pressure exceeds a fracture point.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the exterior material has high tensile strength throughout, then the structural integrity of the battery cell is improved, but the internal pressure cannot be released when swelling occurs
Solution Approach 1:
The exterior material is designed with non-uniform tensile strength distribution, where the first region has lower tensile strength than the second region. This local quality variation allows the first region to act as a pressure release zone while the second region maintains overall structural integrity, resolving the contradiction between strength and pressure control.
Solution Approach 2:
The exterior material is segmented into multiple regions with different tensile strengths. The first region (with lower tensile strength) and second region (with higher tensile strength) are divided based on their functional requirements, allowing differential response to internal pressure while maintaining overall cell integrity.
2Reliability
If a notch portion is added to the exterior material for pressure release, then internal pressure control is improved, but the manufacturing complexity increases
Solution Approach 1:
The notch portion is merged with the exterior material as an integrated structure rather than a separate component. The first region including the notch portion forms a unified exterior material with the second region, simplifying manufacturing by eliminating the need for separate assembly steps while still providing pressure release functionality.
3Reliability
If the tensile strength is reduced in one region, then the notch portion can open for gas release, but the overall strength of the exterior material decreases
Solution Approach 1:
The exterior material exhibits local quality variation where the first region has reduced tensile strength to enable notch opening and gas release, while the second region maintains high tensile strength to preserve overall structural integrity. This localized strength reduction resolves the contradiction between gas release capability and overall strength.
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 battery cell achieves improved internal pressure control and stability, reducing the risk of explosion or fire by allowing controlled gas release through the notch portion, while maintaining the structural integrity of the battery cell.
Implementation Method 1
the tensile strength of the first region is provided to be lower than the tensile strength of the second region... when internal pressure exceeds a fracture point
Data Source
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AI summary
A battery cell of the present disclosure includes: an electrode assembly including a cathode, an anode, and a separator disposed between the cathode and the anode; and an exterior material accommodating the electrode assembly therein, wherein the exterior material includes: a first region including a notch portion provided on an outer surface; and a second region surrounding the first region, wherein the tensile strength of the first region is provided to be lower than the tensile strength of the second region.