Pouch Battery Tab Anchor Structure for Stronger Seal Integrity
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Solution Overview
Problem
Pouch-type battery cells in electrified vehicles are limited by the weakest region of the seal surrounding the tabs, which restricts the maximum allowable internal pressure.
Innovation Solution
A tab assembly is designed with anchor holes in the tabs, where thermoplastic polymer anchors extend through these holes, bonding to both the tab and the pouch films, providing mechanical anchoring and enhancing the seal integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the seal is strengthened around the tabs to increase maximum allowable internal pressure, then the seal strength is improved, but the device complexity increases due to the need for anchor holes and polymer anchoring system
Solution Approach 1:
The polymer anchors are nested within the anchor holes in the tabs, creating a layered structure where the polymer material is positioned inside the pre-formed holes. This nesting approach allows the anchoring system to be integrated within the existing tab structure rather than adding external components, thereby improving seal strength while minimizing increases in device complexity
Solution Approach 2:
The seal structure combines multiple materials: the metal tabs with anchor holes, the thermoplastic polymer anchors, and the pouch films. This composite material system creates a multi-layered anchoring mechanism where each material contributes its specific properties (metal strength, polymer adhesion, film containment) to achieve enhanced overall seal strength without requiring a completely new complex structure
2Reliability
If polymer anchors are added to improve seal integrity, then the seal strength is improved, but the manufacturing process becomes more complex
Solution Approach 1:
The anchor holes are pre-formed in the tabs before the polymer anchors are inserted. This preliminary action allows the structural preparation to be completed during standard tab fabrication, and the polymer anchoring to be added as a subsequent step. This sequencing improves seal integrity while managing manufacturing complexity by breaking the process into manageable stages rather than requiring simultaneous complex operations
Solution Approach 2:
The polymer material undergoes parameter changes during processing, transitioning from a moldable state during injection to a bonded state when heated and pressed against the tab and pouch films. By controlling temperature and pressure parameters during the bonding step, the manufacturing process achieves reliable seal integrity through a straightforward thermal bonding operation rather than requiring complex mechanical assembly
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 mechanical anchoring improves the seal strength, allowing for higher internal pressure without compromising electrical conductivity, thus enhancing the performance and safety of pouch-type battery cells.
Implementation Method 1
The heating causes the polymer films to bond to one another through the at least one anchor hole to form at least one anchor
Implementation Method 2
The polymer is adhered to inner surfaces of the upper and lower pouch films
Data Source
AI summary
A pouch-type battery cell includes metal tabs that extend outside the sealed envelope. To increase seal durability around these tabs, polymer anchors are formed through anchor holes in the tabs during the fabrication process of the tab assemblies. Manufacturing of such tabs can include placing polymer tab films on each side of an electrically conductive tab, the electrically conductive tab having at least one anchor hole, and heating the electrically conductive tab and the polymer tab films causing the polymer tab films to bond to one another through the at least one anchor hole to form at least one anchor.