Electrode Piece Recessed Tab Coating for Thinner Battery Cells
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Solution Overview
Problem
Conventional lithium-ion batteries face issues with excessive thickness near the tab of the electrode piece, leading to increased internal resistance, reduced safety, and impaired charging and discharging rates due to the need for adhesive tapes and other structural factors.
Innovation Solution
The electrode piece design incorporates a recessed area near the tab with a thinner functional layer, comprising a bottom coating layer and an active material layer, where the binder content in the bottom coating layer is higher than in the active material layer, and the thickness of the recessed area is less than that of the normal area, enhancing adhesion and reducing thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional electrode piece with uniform thickness is used, then the battery structure is simple and easy to manufacture, but the cell thickness near the tab becomes excessive, causing safety issues and poor charging/discharging performance
Solution Approach 1:
The electrode piece implements local quality by creating a recessed area near the tab with different thickness characteristics compared to the normal area. Specifically, the functional layer in the recessed area has a smaller thickness than in the normal area, allowing the tab region to have reduced overall thickness while maintaining uniform thickness in other regions. This local differentiation resolves the contradiction by enabling safe tab region thickness without compromising overall manufacturing simplicity.
2Reliability
If the electrode piece thickness is reduced near the tab to improve safety and performance, then charging and discharging rate improve, but the manufacturing process becomes more complex
Solution Approach 1:
The functional layer is segmented into different regions with different thickness characteristics: a normal area with standard thickness and a recessed area near the tab with reduced thickness. This segmentation allows the electrode piece to have optimized local thickness distribution without requiring complete redesign of the entire structure, thus improving safety and performance while limiting the increase in manufacturing complexity to only the specific tab region.
3Strength
If adhesive tape is attached to the tab to secure the electrode, then the electrode is firmly fixed, but the cell thickness near the tab increases further, exacerbating the thickness problem
Solution Approach 1:
The recessed area is pre-formed in the functional layer at the tab region before assembly, creating a localized thickness reduction. This preliminary action ensures that when adhesive tape is subsequently attached to the tab for fixation, the tape adds minimal additional thickness because it is applied to an already thinned region, thereby maintaining both strong fixation and controlled overall thickness.
Data Source
AI summary
The present disclosure provides an electrode piece and a battery. The electrode piece includes a current collector and a functional layer located on a first surface of the current collector, the first surface is provided with a tab, and the functional layer is composed of a normal area away from the tab and a recessed area near the tab, and a thickness of the recessed area is less than a thickness of the normal area. The present disclosure can effectively prevent problems such as excessive thickness of part of a cell near the tab, thereby improving battery qualities such as safety and charging/discharging rate.