Pouch Cell Tab Sealing Structure for Airtight Clamping Strength
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Solution Overview
Problem
Existing pouch cell technologies face challenges in maintaining airtightness and strength, particularly at the clamping parts where the current collecting tab leads are exposed, leading to potential air intrusion and reduced durability.
Innovation Solution
The implementation of an airtightness maintaining member with a slit and a bent part that covers the clamping part, along with reinforcing features such as extending and fold reinforcing parts, enhances the airtightness and strength by preventing air intrusion and reinforcing the clamping area, using a film material that matches the exterior film for improved adhesion and rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current collecting tab lead is drawn out to the outside through the exterior film, then electrical connection is enabled, but airtightness is compromised at the clamping part
Solution Approach 1:
The airtightness maintaining member is divided into distinct functional parts: a bent part that covers the clamping area, an extending part that contacts the tab lead, and a fold reinforcing part. This segmentation allows each part to address specific airtightness issues at different locations where the tab lead exits the exterior film.
Solution Approach 2:
The airtightness maintaining member acts as an intermediary component between the exterior film and the tab lead. It provides an additional sealing layer that maintains airtightness while allowing the tab lead to pass through, effectively mediating between the conflicting requirements of electrical connection and airtightness.
2Strength
If the clamping part is made thinner to accommodate the tab lead, then flexibility is improved, but strength is reduced
Solution Approach 1:
The airtightness maintaining member adds a third dimension to the clamping part structure. By extending beyond the plane of the exterior film and folding back, it creates a multi-layered reinforcement that increases strength without requiring the base clamping part to be more complex.
Solution Approach 2:
The airtightness maintaining member is made of the same material as the exterior film, creating a composite structure when bonded together. This composite approach increases the overall strength and rigidity of the clamping part while maintaining flexibility and avoiding the need for dissimilar materials that would increase complexity.
3Reliability
If the airtightness maintaining member is made larger to improve sealing, then airtightness is improved, but the slit dimension for tab lead passage must be increased
Solution Approach 1:
The airtightness maintaining member provides localized sealing enhancement at critical areas (clamping part and tab lead contact points) rather than requiring a uniform increase in size throughout. The bent part and fold reinforcing part concentrate sealing action where it is most needed, allowing the slit to remain relatively small.
Data Source
AI summary
A pouch cell includes: a charging and discharging element; a current collecting tab lead configured to be thinner than the charging and discharging element and drawn out of the charging and discharging element to an outside; an exterior film configured to wrap the charging and discharging element in a state in which the current collecting tab lead is drawn out to an outside; a clamping part configured to clamp the current collecting tab lead from the exterior film by front and back surfaces in a thickness direction; and an airtightness maintaining member mounted to cover an end portion of the clamping part, wherein the airtightness maintaining member is separated from the exterior film, has a slit through which the current collecting tab lead is drawn out to the outside and has a bent part which covers an end portion of the clamping part, and a dimension of the bent part in the thickness direction of the clamping part is larger than a width dimension of the slit.