Prismatic Winding Core Geometry for Faster Li-Ion Transport
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Solution Overview
Problem
The mismatch between the core forming structure and lithium ion transmission rates in lithium-ion batteries results in slow Li ion transmission, affecting overall rate performance and energy density.
Innovation Solution
A quadrangular prismatic battery design with a winding core having a specific ratio of corner region to middle region areas, controlled between 0.015 and 0.1, ensures appropriate compression and ion transmission rates, preventing issues like slow ion release and safety concerns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the winding core is formed by conventional winding and thermoforming, then the battery structure is simple and easy to manufacture, but the lithium ion transmission rate is slow and rate performance is affected
Solution Approach 1:
The winding core is divided into distinct structural zones: a middle region with uniform thickness for efficient ion transmission, and corner regions with different thickness characteristics. This segmentation allows different parts of the winding core to optimize for their specific functions, resolving the contradiction between manufacturing simplicity and ion transmission efficiency.
Solution Approach 2:
Different regions of the winding core are designed with different thickness characteristics - the middle region maintains uniform thickness while corner regions have specific thickness variations. This local quality differentiation enables optimized lithium ion transmission in each region without compromising overall manufacturability through conventional winding and thermoforming processes.
2Device complexity
If the winding core has uniform structure, then manufacturing is simple, but the mismatch between core structure and Li ion transmission rates in different regions affects energy density
Solution Approach 1:
The winding core structure is segmented into a middle region and corner regions with distinct geometric characteristics. This segmentation creates the necessary structural complexity to match different Li ion transmission requirements in different regions, thereby improving energy density without significantly complicating the manufacturing process.
Solution Approach 2:
The winding core transitions from a uniform symmetric structure to an asymmetric structure where corner regions differ from the middle region in thickness and geometry. This asymmetry allows the core structure to better match the non-uniform Li ion transmission rates that occur naturally in wound battery structures, improving overall energy density.
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 the energy density and rate performance of lithium-ion batteries while ensuring safety and preventing issues like lithium precipitation and short circuits, thereby improving the battery's overall performance and service life.
Implementation Method 1
The process of charging and discharging is achieved by lithium ions in the electrolyte moving back and forth between the positive electrode piece and the negative electrode piece
Data Source
Figure 1~2
Figure 3
AI summary
A single battery (100) includes a casing (10) having an accommodating cavity (11) and at least one winding core (20) accommodated in the accommodating cavity (11). The winding core (20) includes positive and negative electrode pieces and a separator (23). After being laminated, the winding core (20) is formed with flat surfaces (24) opposite to each other and corner regions (22) connected to two sides of the opposite flat surfaces (24). Distance between the flat surfaces (24) opposite to each other is h. Four endpoints connecting the opposite flat surfaces (24) and the corner regions (22) and the opposite flat surfaces (24) surround and form a middle region (21). The middle region (21) has rectangular structure. Length of the middle region (21) in winding direction is d, and maximum thickness of each of the corner regions (22) in the winding direction is a, where 0.015≤2a2/dh≤0.1.