Pouch Battery Tab Welding to Side Surface
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Solution Overview
Problem
Conventional pouch-type secondary batteries have a low internal spatial utility due to the large non-electrode region required for surface-wise direction welding of electrode tabs and leads, which limits the battery's capacity and efficiency.
Innovation Solution
The battery design involves welding the electrode tab to the side surface of the electrode lead in a thickness-wise direction, reducing the welding width to less than 1 mm, and using friction stir welding to form a thicker electrode lead, allowing for increased capacity and improved cooling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface-wise direction welding is used to join electrode tab and electrode lead, then reliable electrical connection is achieved, but internal spatial utility is reduced due to large non-electrode region
Solution Approach 1:
The patent transitions from surface-wise direction welding (2D plane welding) to thickness-wise direction welding (3D depth welding). By welding the electrode tab to the side surface of the electrode lead in the thickness direction, the welding area moves from the surface plane to the thickness dimension, significantly reducing the required surface area for welding while maintaining connection reliability.
Solution Approach 2:
Instead of welding the electrode tab to the top/bottom surface of the electrode lead (conventional approach), the patent inverts the welding direction to join the electrode tab to the side surface of the electrode lead. This inversion of the welding orientation reduces the surface area occupied by the welding zone and minimizes the non-electrode region.
2Strength
If welding width is increased to ensure connection strength, then joint strength is improved, but non-electrode region size increases reducing battery capacity
Solution Approach 1:
The patent increases joint strength by utilizing the thickness dimension for welding rather than expanding the surface welding width. By welding through the thickness of the electrode lead to the side surface, the connection strength is enhanced in the depth direction while keeping the surface footprint minimal, thus preserving battery capacity.
3Temperature
If electrode lead thickness is increased to improve cooling performance, then cooling performance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The patent combines two functions into the electrode lead: electrical conduction and thermal management. By increasing the electrode lead thickness and utilizing it as a heat dissipation pathway, the cooling function is integrated into the existing electrical component, eliminating the need for separate cooling structures and simplifying the overall manufacturing process.
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
This design reduces the non-electrode region, increases the electrode assembly size, and enhances cooling performance by minimizing the welding width and increasing the thickness of the electrode lead, thereby maximizing spatial utility and battery capacity.
Implementation Method 1
welding the electrode tab to the side surface of the electrode lead in a thickness-wise direction, and a width of the welded part is less than or equal to 1 mm in the length-wise direction of the electrode lead
Data Source
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AI summary
Provided is a pouch-type secondary battery which can increase spatial utility by reducing the length of a non-electrode region and a method for fabricating the same. The secondary battery according to the present disclosure is a secondary battery having a sealed structure such that an electrode assembly of positive electrode plate/separator/negative electrode plate is embedded in a pouch case and an electrode tab of the electrode assembly is joined to an electrode lead and juts outside, wherein the electrode tab is welded to a side surface perpendicular to a surface-wise direction of the secondary battery on the electrode lead arranged parallel to the surface-wise direction of the secondary battery, to form a welded part in a thickness-wise direction of the electrode lead between the electrode lead and the electrode tab.