Pouch Cell Sealing Layout With Weak-Section Venting Path
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Solution Overview
Problem
Conventional pouch-type secondary batteries face issues with uncontrolled venting of internal gas due to swelling, leading to safety hazards such as electrolyte leakage and potential explosions, as the entire pouch case is thermally fused, preventing controlled gas discharge.
Innovation Solution
A battery cell design with a pouch case featuring a strong and weak sealing section and a venting path, allowing controlled venting of internal gas in a specific direction through a venting path formed in the sealing portion, which includes an inlet and outlet, and a layered structure with varying sealing strengths to manage gas discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the entire pouch case is thermally fused for sealing, then strong bonding of the pouch case is achieved, but internal gas cannot be properly vented and accumulates inside
Solution Approach 1:
The sealing portion is divided into different regions with different sealing strengths: a first sealing portion with strong bonding for structural integrity, and a second sealing portion with weak bonding that forms a venting path for controlled gas discharge. This local differentiation allows simultaneous achievement of strong overall sealing and localized gas venting capability.
2Reliability
If the pouch case is made completely sealed, then battery protection is improved, but uncontrolled bursting occurs when internal pressure exceeds withstand capacity
Solution Approach 1:
A venting path is pre-formed in the second sealing portion during the sealing process, creating a predetermined weak path for gas discharge before any swelling or pressure buildup occurs. This preliminary preparation ensures that when internal gas is generated, it will discharge through the controlled venting path rather than causing uncontrolled bursting.
3Stability of the object's composition
If thermal fusion is applied to the entire pouch case, then sealing integrity is enhanced, but gas venting capability is eliminated
Solution Approach 1:
The sealing portion is segmented into multiple functional areas: a first sealing portion extending in a first direction with strong thermal fusion for maintaining sealing integrity, and a second sealing portion extending in a second direction with weak thermal fusion that forms the venting path. This segmentation allows the sealing structure to simultaneously provide both integrity and gas venting 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 design enables controlled venting of internal gas, increasing the accumulated flow rate and delaying venting time, improving safety by preventing uncontrolled discharge and maximizing battery capacity without additional volume, thus enhancing the safety and efficiency of the battery cell.
Implementation Method 1
a thermal fusion process is performed on the entire upper and lower cases of the pouch case, resulting in strong bonding of the entire pouch case
Data Source
AI summary
A battery cell includes an electrode assembly and a pouch case for sealing the electrode assembly together with an electrolyte, wherein the pouch case includes a receiving portion in which the electrode assembly is accommodated; and a sealing portion disposed on the perimeter of the receiving portion to seal the electrode assembly, wherein the sealing portion includes a strong sealing section and a weak sealing section, wherein the weak sealing section forms a venting path in the sealing portion, and wherein the venting path includes an inlet located on the inner surface of the sealing portion connected to the receiving portion and an outlet located on the outer surface of the sealing portion integrally connected to the inlet.