Pouch Battery Cell Sealing Structure for Venting and Corrosion Control
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Solution Overview
Problem
Conventional pouch battery cells experience venting and electrical corrosion issues due to gas generation, leading to dimensional instability and performance degradation.
Innovation Solution
The pouch battery cell design features recessed and bent sealing portions within the battery case, allowing for improved dimensional stability and preventing electrical corrosion by containing gas and maintaining electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pouch battery cell is sealed with conventional sealing portions, then the battery case can be sealed to contain electrolyte solution, but gas generated during charging and discharging causes swelling and venting due to high internal pressure
Solution Approach 1:
The sealing portion is divided into multiple sections: a first sealing portion that seals the battery case, and a second sealing portion that extends from the first sealing portion to seal the exposed metal plate. This segmentation allows different parts of the sealing structure to perform different functions, with the second sealing portion specifically protecting against venting by covering the metal plate that would otherwise be exposed during swelling.
Solution Approach 2:
The second sealing portion is formed in advance to cover the metal plate before any swelling or venting occurs. This preliminary sealing action prevents gas from escaping through the metal plate during subsequent charging and discharging cycles, thereby maintaining dimensional stability and preventing venting.
2Ease of operation
If the metal plate is exposed at the sealing portion, then electrical connections can be maintained, but electrical corrosion occurs when negative potential is generated during charging and discharging
Solution Approach 1:
The sealing structure is segmented into a first sealing portion for sealing the battery case and a second sealing portion for protecting the metal plate. The second sealing portion specifically addresses the electrical corrosion problem by covering the exposed metal plate while allowing electrical connections to be maintained through the sealed structure.
Solution Approach 2:
The second sealing portion acts as an intermediary barrier between the exposed metal plate and the external environment. It prevents direct contact between the metal plate and corrosive elements while maintaining the electrical connection function, thus protecting against electrical corrosion.
3Device complexity
If the sealing portion is exposed to the outside, then the battery structure can be simplified, but electrical corrosion occurs and moisture blocking function is lost
Solution Approach 1:
The sealing portion is segmented into a first sealing portion for sealing the battery case and a second sealing portion for protecting the metal plate and maintaining moisture blocking function. This segmentation adds minimal complexity while significantly improving reliability by preventing moisture ingress and electrical corrosion.
Solution Approach 2:
The second sealing portion serves multiple functions: it seals the exposed metal plate, prevents electrical corrosion, maintains moisture blocking function, and protects against venting. This multi-functionality addresses multiple reliability issues with a single structural element, minimizing the increase in device complexity.
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 effectively delays venting and prevents electrical corrosion, enhancing stability and manufacturing ease by containing gas within the battery case and maintaining electrical connections.
Implementation Method 1
the upper case and the lower case include a sealing portion formed by heat-sealing the outer peripheral surfaces of the upper case and the lower case
Data Source
Figure 1
Figure 2(a)~2(b)
Figure 3
AI summary
A pouch battery cell according to one embodiment of the present disclosure includes an electrode assembly including a cathode, an anode and a separator interposed between the cathode and the anode; and a battery case to which the electrode assembly is attached, wherein the battery case comprises an upper case, a lower case, and a receiving portion formed between the upper case and the lower case, wherein the battery case is formed with sealing portions in which outer peripheral surfaces of the upper case and the lower case are heat-sealed to each other, and wherein one end of at least a part of the sealing portions is recessed in the inside of the battery case.