Sloped Electrode Lead Structure for Swelling-Stable Battery Tabs
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Solution Overview
Problem
The disconnection of electrode tabs in secondary batteries due to volume shrinkage and swelling, particularly in silicon-based anode materials, leads to lithium precipitation and reduced battery lifespan and storage performance.
Innovation Solution
An electrode lead structure with varying thicknesses and slopes is introduced, featuring a first lead portion thicker than a second lead portion, and a third lead portion with increasing thickness from the second to the first, accompanied by a lead film for enhanced sealing and reduced tension on the electrode tab.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If silicon-based anode materials are used to increase energy density, then battery capacity is improved, but volume shrinkage and swelling during charging and discharging increases, causing electrode tab disconnection
Solution Approach 1:
The electrode lead structure employs varying thickness parameters along its length, with the first lead portion having a greater thickness than the second lead portion. This parameter change allows the structure to accommodate volume variations in silicon-based anode materials during charging and discharging, reducing stress on the electrode tab while maintaining high battery capacity
Solution Approach 2:
The electrode lead structure combines multiple portions with different thicknesses (first lead portion with greater thickness, second lead portion with lesser thickness, and third lead portion with slope) to create a composite structure that provides both mechanical strength and flexibility, enabling it to handle the expansion and contraction of silicon-based anode materials
2Productivity
If continuous charging and discharging cycles are performed, then battery usage is maintained, but repeated shrinkage and swelling apply pressure to electrode tabs, causing disconnection
Solution Approach 1:
The third lead portion with its sloped structure acts as a cushioning element that anticipates and absorbs the stress from repeated shrinkage and swelling during charging and discharging cycles. This beforehand cushioning prevents stress concentration at the electrode tab connection point, maintaining connection reliability during continuous battery usage
Solution Approach 2:
The electrode lead structure with its varying thickness and sloped third lead portion provides dynamic flexibility to accommodate the continuous changes in volume during charging and discharging cycles, allowing the structure to adapt to repeated shrinkage and swelling without causing electrode tab disconnection
3Reliability
If electrode tab disconnection is prevented through thicker lead portions, then connection stability is improved, but battery assembly space is reduced
Solution Approach 1:
The electrode lead structure applies local quality by having the first lead portion with greater thickness only where needed for connection stability, while the second lead portion has lesser thickness to conserve space. The third lead portion with its slope provides a gradual transition, ensuring mechanical strength is concentrated where required without unnecessarily reducing overall battery assembly space
Data Source
AI summary
Provided are an electrode lead structure for a secondary battery and a secondary battery including the same. The electrode lead structure includes an electrode lead and a lead film, wherein the electrode lead includes a first lead portion to which an electrode tab is bonded, a second lead portion, having a thickness less than that of the first lead portion, and a third lead portion formed between the first lead portion and the second lead portion and having a slope in which a thickness increases in a direction from the second lead portion to the first lead portion, and the lead film is positioned on the third lead portion.