Composite Tab Adhesive Structure for Bendable Thick Battery Tabs
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Solution Overview
Problem
The use of thick tab adhesives in batteries results in reduced energy density due to their inflexibility, which occupies significant space and affects packaging reliability.
Innovation Solution
A composite tab adhesive structure with two layers, where the second layer is made of polyethylene, polypropylene, or polyethylene terephthalate, with a thickness less than or equal to 70 µm, allowing for bending and insulating properties, while the first layer meets packaging requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the tab adhesive is increased to meet packaging requirements for thick tabs, then packaging reliability is improved, but the adhesive becomes too thick to bend and occupies excessive space, resulting in reduced energy density
Solution Approach 1:
The tab adhesive is divided into two distinct layers: a first layer with thickness of 70-150 μm that provides packaging reliability and gap filling, and a second layer with thickness of 30-70 μm that provides bending flexibility. This segmentation allows each layer to optimize for its specific function, resolving the contradiction between packaging reliability and bendability.
Solution Approach 2:
Different regions of the tab adhesive structure are assigned different thicknesses and properties. The first layer near the packaging interface has greater thickness for reliable sealing, while the second layer extending outward has reduced thickness for flexibility. This local differentiation enables the adhesive to simultaneously satisfy both packaging and bending requirements in different spatial zones.
2Power
If a thick tab is used to increase current-carrying capacity, then electrical performance is improved, but the required tab adhesive thickness increases, leading to reduced energy density
Solution Approach 1:
The segmented adhesive structure allows the first layer to be optimized for thick tab packaging (70-150 μm thickness) while the second layer maintains flexibility with reduced thickness (30-70 μm). This enables thick tabs to be used for high current carrying without proportionally increasing the space occupied by the adhesive.
3Loss of energy
If the tab adhesive thickness is reduced to improve energy density, then space utilization is improved, but packaging reliability deteriorates due to insufficient gap filling capability
Solution Approach 1:
The first layer of the tab adhesive (70-150 μm thick) is specifically designed to provide sufficient gap filling capability for packaging reliability, while the overall adhesive structure maintains reduced total thickness (with the second layer being 30-70 μm) to preserve energy density. The segmentation allows the critical packaging function to be fulfilled without requiring the entire adhesive to be thick.
Solution Approach 2:
The adhesive structure concentrates its thickness where it is most needed for packaging reliability (first layer at the packaging interface), while reducing thickness in regions where flexibility is more important (second layer extending outward). This local optimization ensures packaging reliability is maintained while minimizing overall space occupation.
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 solution increases energy density by reducing the overall length of the battery and enhances packaging reliability by ensuring the adhesive can bend without occupying excessive space.
Implementation Method 1
A material of the second adhesive body comprises one or more selected from the group consisting of polyethylene, polypropylene and polyethylene terephthalate
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A tab assembly (100) includes a tab (1) and a tab adhesive (2). Along a thickness direction (X) of the tab (1), the tab (1) includes a first surface (11) and a second surface (12) opposite to each other. Both the first surface (11) and the second surface (12) are provided with the tab adhesive (2). The tab adhesive (2) provided on the first surface (11) and the tab adhesive (2) provided on the second surface (12) jointly wrap the tab (1). Along a length direction (Y) of the tab (1), the tab (1) includes a first end (1a) and a second end (1b) opposite to each other. The tab adhesive (2) includes a first layer (21) and a second layer (22). The first layer (21) and the second layer (22) are stacked along a direction from the first end (1a) to the second end (1b). The first layer (21) includes a first adhesive body (211). The second layer (22) includes at least one layer of a second adhesive body (221). A material of the second adhesive body (221) comprises one or more selected from the group consisting of polyethylene, polypropylene and polyethylene terephthalate. A thickness of the tab (1) is Ti, and a thickness of the second adhesive body (221) is T2, Ti ≥ 80 µm, and T2 ≤ 70 µm.