Center-Tab Secondary Battery Electrode Layout Against Lithium Plating
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In secondary batteries with a center-tab structure, lithium ions bypass protection adhesives and accumulate at local positions on the negative electrode plate, leading to excessive concentration and lithium plating, which can cause short circuits and reduce battery performance.
Innovation Solution
The implementation of grooves and insulation layers with perforations in the positive and negative electrode plates, along with strategically placed holes, to manage lithium ion distribution and prevent excessive accumulation, thereby reducing the likelihood of lithium plating and enhancing energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a center-tab structure is adopted to achieve faster charging speed, then charging speed is improved, but lithium ions bypass the protection adhesive and accumulate at local positions on the negative electrode plate, causing lithium plating
Solution Approach 1:
The negative electrode protection adhesive is segmented into multiple regions: a first protection adhesive region covering the welding area, and a second protection adhesive region with through holes. This segmentation allows different zones to perform different functions - the first region provides comprehensive coverage while the second region with through holes enables lithium ion penetration to prevent plating at the edges.
Solution Approach 2:
The second protection adhesive region is designed as a porous structure with through holes, allowing lithium ions to pass through while the adhesive still provides protection. This porous design resolves the contradiction by enabling both protection and ion transport, preventing lithium ion accumulation at the edges that would otherwise cause plating.
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 effectively reduces the probability of lithium plating and short circuits while maintaining fast charging speeds and energy density by managing lithium ion distribution and improving the bonding force of insulation layers.
Implementation Method 1
The first positive electrode insulation layer covers the first groove, so as to cover welding burrs of the positive tab and the positive current collector exposed by the first groove
Implementation Method 2
a first negative electrode insulation layer is disposed on a surface of the negative electrode plate facing the first positive active material layer. Along a direction perpendicular to a surface of the first negative electrode insulation layer, a projection of the first negative electrode insulation layer on the first positive active material layer covers the first groove
Implementation Method 3
Along a width direction of the first groove, a first hole is provided on one side of the first negative electrode insulation layer, so as to enable lithium ions on one side of the first negative electrode insulation layer to be absorbed by the negative electrode plate through the first hole
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A secondary battery (100) includes a negative electrode plate (22), a positive electrode plate (21), and a separator (23). The positive electrode plate (21) includes a positive current collector (211), a first positive active material layer (212), and a positive tab (213). Along a thickness direction of the positive current collector (211), a surface of the positive current collector (211) is provided with the first positive active material layer (212). The first positive active material layer (212) is provided with a first groove (2121). The positive tab (213) is disposed in the first groove (2121) and is electrically connected to the positive current collector (211). A first positive electrode insulation layer (24) is disposed on a surface of the first positive active material layer (212) facing the negative electrode plate (22). The first positive electrode insulation layer (24) covers the first groove (2121). A first negative electrode insulation layer (24) is disposed on a surface of the negative electrode plate (22) facing the first positive active material layer (212). Along a direction perpendicular to a surface of the first negative electrode insulation layer (25), a projection of the first negative electrode insulation layer (25) on the first positive active material layer (212) covers the first groove (2121). Along a width direction of the first groove (2121), a first hole (2521) is provided on one side of the first negative electrode insulation layer (25).