Electrode Plate Slope Coating Near the Tab for Safer Li-Ion Batteries
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Solution Overview
Problem
Conventional lithium-ion batteries face issues with high internal resistance due to the height difference between the functional coating layer and the current collector near the tab, leading to electrolyte enrichment, lithium precipitation, and reduced safety and rate capability.
Innovation Solution
The electrode piece design incorporates a functional layer with a slope area near the tab, ensuring the adhesive tape can adhere tightly, reducing the height difference and preventing electrolyte enrichment, thereby improving safety and rate capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional aluminum foil collector is used, then the battery structure is simple and manufacturing is easy, but the collector deforms due to volume expansion of the negative electrode during charging, causing contact loss and reduced reliability
Solution Approach 1:
The collector is divided into a body portion and a protruding portion that extends into the expansion space. This segmentation allows the collector to accommodate volume expansion of the negative electrode while maintaining electrical contact, resolving the contradiction between reliability and structural simplicity.
Solution Approach 2:
The collector extends in the thickness direction of the battery by creating a protruding portion that protrudes from one surface of the body. This dimensional extension provides accommodation space for electrode expansion while maintaining contact reliability without significantly increasing overall structural complexity.
2Reliability
If the collector is made larger to accommodate expansion space, then contact reliability is maintained, but the battery volume increases and energy density decreases
Solution Approach 1:
The collector has different structures in different regions: a body portion with standard dimensions and a localized protruding portion that extends into the expansion space. This local quality change allows the collector to maintain contact reliability only where needed (at the protruding end) while minimizing the overall volume increase of the battery.
3Reliability
If the collector protrudes into the expansion space, then volume expansion is accommodated and contact is maintained, but the collector may contact the positive electrode causing short circuits
Solution Approach 1:
A separator is positioned between the protruding portion of the collector and the positive electrode, acting as an intermediary that prevents direct contact and potential short circuits while allowing the collector to maintain its protruding structure for reliable contact with the negative electrode.
4Reliability
If the collector has a large protruding portion to ensure contact, then contact reliability is maintained, but the amount of collector material increases and manufacturing cost rises
Solution Approach 1:
The collector has a protruding portion that extends only partially into the expansion space, just enough to maintain contact reliability during electrode expansion. This partial action approach avoids using excessive collector material while still achieving the required contact reliability, thus reducing manufacturing costs.
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 design enhances the protection of the tab area, preventing lithium precipitation and improving the safety, stability, and use life of the electrode and battery.
Implementation Method 1
a separator between the positive electrode and the negative electrode, thereby preventing direct contact between the positive and negative electrodes
Data Source
Figure 1~2
AI summary
The present invention provides an electrode piece and a battery. The electrode piece includes a current collector and a functional layer arranged on a first surface of the current collector, a tab is further arranged in middle of the first surface, and the functional layer on the first surface has a first slope area near the tab and a first normal area away from the tab, and a thickness of the first slope area gradually decreases along a direction towards the tab. The present invention can improve performances of the battery, such as rate capacity, safety and the like.