Rechargeable Battery Polymer Core Buffer
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Solution Overview
Problem
Rechargeable lithium batteries with non-carbon-based negative active materials face substrate expansion issues during charge and discharge, leading to misshapen electrode assemblies and increased manufacturing complexity due to the need for additional processes like center pin insertion, which affects cycle-life characteristics and costs.
Innovation Solution
The battery design features a spirally wound electrode assembly with partially coated positive and negative electrodes, including uncoated regions without active materials at the core, which can expand or shrink, and a polymer layer on these regions to prevent misshapen cores, using materials like Si, SnO2, and transition element oxides, eliminating the need for a center pin and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-carbon-based negative active materials (Si, Sn, etc.) are used to achieve high capacity, then battery capacity is improved, but substrate expansion during charge and discharge causes the electrode assembly core to become misshapen, deteriorating cycle-life characteristics
Solution Approach 1:
The electrode assembly is divided into an inner core region (without active materials) and an outer active region (with active materials). The inner core acts as an expansion buffer that can accommodate substrate expansion without affecting the overall structure, while the outer region maintains electrochemical functionality. This segmentation allows high-capacity materials to be used while preventing core misshaping.
Solution Approach 2:
A buffer layer is introduced between the active materials and the current collector in the inner core region. This buffer layer serves as an intermediary that absorbs expansion stress, preventing direct transmission of expansion forces to the current collector and maintaining structural integrity during charge-discharge cycles.
2Stability of the object's composition
If a center pin is inserted to prevent substrate expansion and maintain core shape, then structural stability is improved, but the manufacturing process becomes complicated and manufacturing cost increases
Solution Approach 1:
The center pin is completely removed from the electrode assembly design. Instead of using an external support structure, the patent creates an self-supporting inner core structure composed of current collectors and buffer layers that inherently maintains shape stability without requiring insertion of additional components.
Solution Approach 2:
The electrode assembly structure serves its own support function through the designed inner core region with buffer layers. The structure is self-sufficient in maintaining shape stability during expansion, eliminating the need for external center pins or additional support mechanisms.
3Shape
If a center pin is inserted to prevent expansion, then core misshaping is prevented, but additional manufacturing steps are required, increasing manufacturing cost
Solution Approach 1:
The support function previously requiring a separate center pin is merged into the electrode assembly structure itself through the inner core region design. The current collectors and buffer layers in the inner core collectively provide the shape-maintaining function, eliminating the need for separate support components and simplifying manufacturing.
Solution Approach 2:
The center pin component and its associated insertion process are completely extracted from the manufacturing system. The patent achieves core shape stability through the inherent structure of the electrode assembly, requiring no additional components or steps beyond standard electrode fabrication.
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 enhances cycle-life characteristics by preventing core distortion and simplifies the manufacturing process, reducing costs and improving productivity while maintaining high capacity and structural stability.
Implementation Method 1
the positive and negative uncoated regions are coated with a polymer
Implementation Method 2
Rechargeable lithium batteries generate electrical energy through an oxidation/reduction reaction during the intercalation/deintercalation of lithium ions
Data Source
AI summary
A rechargeable lithium battery including an electrode assembly having a positive electrode including a positive current collector partially coated with a positive active material to form a positive coated region and a positive uncoated region, a negative electrode including a negative current collector partially coated with a negative active material to form a negative coated region and a negative uncoated region and a separator between the positive electrode and the negative electrode. The electrode assembly is spirally wound a plurality of times with the positive uncoated region and the negative uncoated region together forming a core central to the spirally-wound electrode assembly and wound from 3 to 15 times.